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
1257 * perf_addr_filters_head::lock
1261 * cpuctx->mutex / perf_event_context::mutex
1263 static struct perf_event_context *
1264 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1266 struct perf_event_context *ctx;
1270 ctx = READ_ONCE(event->ctx);
1271 if (!atomic_inc_not_zero(&ctx->refcount)) {
1277 mutex_lock_nested(&ctx->mutex, nesting);
1278 if (event->ctx != ctx) {
1279 mutex_unlock(&ctx->mutex);
1287 static inline struct perf_event_context *
1288 perf_event_ctx_lock(struct perf_event *event)
1290 return perf_event_ctx_lock_nested(event, 0);
1293 static void perf_event_ctx_unlock(struct perf_event *event,
1294 struct perf_event_context *ctx)
1296 mutex_unlock(&ctx->mutex);
1301 * This must be done under the ctx->lock, such as to serialize against
1302 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1303 * calling scheduler related locks and ctx->lock nests inside those.
1305 static __must_check struct perf_event_context *
1306 unclone_ctx(struct perf_event_context *ctx)
1308 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1310 lockdep_assert_held(&ctx->lock);
1313 ctx->parent_ctx = NULL;
1319 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1324 * only top level events have the pid namespace they were created in
1327 event = event->parent;
1329 nr = __task_pid_nr_ns(p, type, event->ns);
1330 /* avoid -1 if it is idle thread or runs in another ns */
1331 if (!nr && !pid_alive(p))
1336 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1338 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1341 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1343 return perf_event_pid_type(event, p, PIDTYPE_PID);
1347 * If we inherit events we want to return the parent event id
1350 static u64 primary_event_id(struct perf_event *event)
1355 id = event->parent->id;
1361 * Get the perf_event_context for a task and lock it.
1363 * This has to cope with with the fact that until it is locked,
1364 * the context could get moved to another task.
1366 static struct perf_event_context *
1367 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1369 struct perf_event_context *ctx;
1373 * One of the few rules of preemptible RCU is that one cannot do
1374 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1375 * part of the read side critical section was irqs-enabled -- see
1376 * rcu_read_unlock_special().
1378 * Since ctx->lock nests under rq->lock we must ensure the entire read
1379 * side critical section has interrupts disabled.
1381 local_irq_save(*flags);
1383 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1386 * If this context is a clone of another, it might
1387 * get swapped for another underneath us by
1388 * perf_event_task_sched_out, though the
1389 * rcu_read_lock() protects us from any context
1390 * getting freed. Lock the context and check if it
1391 * got swapped before we could get the lock, and retry
1392 * if so. If we locked the right context, then it
1393 * can't get swapped on us any more.
1395 raw_spin_lock(&ctx->lock);
1396 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1397 raw_spin_unlock(&ctx->lock);
1399 local_irq_restore(*flags);
1403 if (ctx->task == TASK_TOMBSTONE ||
1404 !atomic_inc_not_zero(&ctx->refcount)) {
1405 raw_spin_unlock(&ctx->lock);
1408 WARN_ON_ONCE(ctx->task != task);
1413 local_irq_restore(*flags);
1418 * Get the context for a task and increment its pin_count so it
1419 * can't get swapped to another task. This also increments its
1420 * reference count so that the context can't get freed.
1422 static struct perf_event_context *
1423 perf_pin_task_context(struct task_struct *task, int ctxn)
1425 struct perf_event_context *ctx;
1426 unsigned long flags;
1428 ctx = perf_lock_task_context(task, ctxn, &flags);
1431 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1436 static void perf_unpin_context(struct perf_event_context *ctx)
1438 unsigned long flags;
1440 raw_spin_lock_irqsave(&ctx->lock, flags);
1442 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1446 * Update the record of the current time in a context.
1448 static void update_context_time(struct perf_event_context *ctx)
1450 u64 now = perf_clock();
1452 ctx->time += now - ctx->timestamp;
1453 ctx->timestamp = now;
1456 static u64 perf_event_time(struct perf_event *event)
1458 struct perf_event_context *ctx = event->ctx;
1460 if (is_cgroup_event(event))
1461 return perf_cgroup_event_time(event);
1463 return ctx ? ctx->time : 0;
1466 static enum event_type_t get_event_type(struct perf_event *event)
1468 struct perf_event_context *ctx = event->ctx;
1469 enum event_type_t event_type;
1471 lockdep_assert_held(&ctx->lock);
1474 * It's 'group type', really, because if our group leader is
1475 * pinned, so are we.
1477 if (event->group_leader != event)
1478 event = event->group_leader;
1480 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1482 event_type |= EVENT_CPU;
1488 * Helper function to initialize event group nodes.
1490 static void init_event_group(struct perf_event *event)
1492 RB_CLEAR_NODE(&event->group_node);
1493 event->group_index = 0;
1497 * Extract pinned or flexible groups from the context
1498 * based on event attrs bits.
1500 static struct perf_event_groups *
1501 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1503 if (event->attr.pinned)
1504 return &ctx->pinned_groups;
1506 return &ctx->flexible_groups;
1510 * Helper function to initializes perf_event_group trees.
1512 static void perf_event_groups_init(struct perf_event_groups *groups)
1514 groups->tree = RB_ROOT;
1519 * Compare function for event groups;
1521 * Implements complex key that first sorts by CPU and then by virtual index
1522 * which provides ordering when rotating groups for the same CPU.
1525 perf_event_groups_less(struct perf_event *left, struct perf_event *right)
1527 if (left->cpu < right->cpu)
1529 if (left->cpu > right->cpu)
1532 if (left->group_index < right->group_index)
1534 if (left->group_index > right->group_index)
1541 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1542 * key (see perf_event_groups_less). This places it last inside the CPU
1546 perf_event_groups_insert(struct perf_event_groups *groups,
1547 struct perf_event *event)
1549 struct perf_event *node_event;
1550 struct rb_node *parent;
1551 struct rb_node **node;
1553 event->group_index = ++groups->index;
1555 node = &groups->tree.rb_node;
1560 node_event = container_of(*node, struct perf_event, group_node);
1562 if (perf_event_groups_less(event, node_event))
1563 node = &parent->rb_left;
1565 node = &parent->rb_right;
1568 rb_link_node(&event->group_node, parent, node);
1569 rb_insert_color(&event->group_node, &groups->tree);
1573 * Helper function to insert event into the pinned or flexible groups.
1576 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1578 struct perf_event_groups *groups;
1580 groups = get_event_groups(event, ctx);
1581 perf_event_groups_insert(groups, event);
1585 * Delete a group from a tree.
1588 perf_event_groups_delete(struct perf_event_groups *groups,
1589 struct perf_event *event)
1591 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1592 RB_EMPTY_ROOT(&groups->tree));
1594 rb_erase(&event->group_node, &groups->tree);
1595 init_event_group(event);
1599 * Helper function to delete event from its groups.
1602 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1604 struct perf_event_groups *groups;
1606 groups = get_event_groups(event, ctx);
1607 perf_event_groups_delete(groups, event);
1611 * Get the leftmost event in the @cpu subtree.
1613 static struct perf_event *
1614 perf_event_groups_first(struct perf_event_groups *groups, int cpu)
1616 struct perf_event *node_event = NULL, *match = NULL;
1617 struct rb_node *node = groups->tree.rb_node;
1620 node_event = container_of(node, struct perf_event, group_node);
1622 if (cpu < node_event->cpu) {
1623 node = node->rb_left;
1624 } else if (cpu > node_event->cpu) {
1625 node = node->rb_right;
1628 node = node->rb_left;
1636 * Like rb_entry_next_safe() for the @cpu subtree.
1638 static struct perf_event *
1639 perf_event_groups_next(struct perf_event *event)
1641 struct perf_event *next;
1643 next = rb_entry_safe(rb_next(&event->group_node), typeof(*event), group_node);
1644 if (next && next->cpu == event->cpu)
1651 * Iterate through the whole groups tree.
1653 #define perf_event_groups_for_each(event, groups) \
1654 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1655 typeof(*event), group_node); event; \
1656 event = rb_entry_safe(rb_next(&event->group_node), \
1657 typeof(*event), group_node))
1660 * Add an event from the lists for its context.
1661 * Must be called with ctx->mutex and ctx->lock held.
1664 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1666 lockdep_assert_held(&ctx->lock);
1668 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1669 event->attach_state |= PERF_ATTACH_CONTEXT;
1671 event->tstamp = perf_event_time(event);
1674 * If we're a stand alone event or group leader, we go to the context
1675 * list, group events are kept attached to the group so that
1676 * perf_group_detach can, at all times, locate all siblings.
1678 if (event->group_leader == event) {
1679 event->group_caps = event->event_caps;
1680 add_event_to_groups(event, ctx);
1683 list_update_cgroup_event(event, ctx, true);
1685 list_add_rcu(&event->event_entry, &ctx->event_list);
1687 if (event->attr.inherit_stat)
1694 * Initialize event state based on the perf_event_attr::disabled.
1696 static inline void perf_event__state_init(struct perf_event *event)
1698 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1699 PERF_EVENT_STATE_INACTIVE;
1702 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1704 int entry = sizeof(u64); /* value */
1708 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1709 size += sizeof(u64);
1711 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1712 size += sizeof(u64);
1714 if (event->attr.read_format & PERF_FORMAT_ID)
1715 entry += sizeof(u64);
1717 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1719 size += sizeof(u64);
1723 event->read_size = size;
1726 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1728 struct perf_sample_data *data;
1731 if (sample_type & PERF_SAMPLE_IP)
1732 size += sizeof(data->ip);
1734 if (sample_type & PERF_SAMPLE_ADDR)
1735 size += sizeof(data->addr);
1737 if (sample_type & PERF_SAMPLE_PERIOD)
1738 size += sizeof(data->period);
1740 if (sample_type & PERF_SAMPLE_WEIGHT)
1741 size += sizeof(data->weight);
1743 if (sample_type & PERF_SAMPLE_READ)
1744 size += event->read_size;
1746 if (sample_type & PERF_SAMPLE_DATA_SRC)
1747 size += sizeof(data->data_src.val);
1749 if (sample_type & PERF_SAMPLE_TRANSACTION)
1750 size += sizeof(data->txn);
1752 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1753 size += sizeof(data->phys_addr);
1755 event->header_size = size;
1759 * Called at perf_event creation and when events are attached/detached from a
1762 static void perf_event__header_size(struct perf_event *event)
1764 __perf_event_read_size(event,
1765 event->group_leader->nr_siblings);
1766 __perf_event_header_size(event, event->attr.sample_type);
1769 static void perf_event__id_header_size(struct perf_event *event)
1771 struct perf_sample_data *data;
1772 u64 sample_type = event->attr.sample_type;
1775 if (sample_type & PERF_SAMPLE_TID)
1776 size += sizeof(data->tid_entry);
1778 if (sample_type & PERF_SAMPLE_TIME)
1779 size += sizeof(data->time);
1781 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1782 size += sizeof(data->id);
1784 if (sample_type & PERF_SAMPLE_ID)
1785 size += sizeof(data->id);
1787 if (sample_type & PERF_SAMPLE_STREAM_ID)
1788 size += sizeof(data->stream_id);
1790 if (sample_type & PERF_SAMPLE_CPU)
1791 size += sizeof(data->cpu_entry);
1793 event->id_header_size = size;
1796 static bool perf_event_validate_size(struct perf_event *event)
1799 * The values computed here will be over-written when we actually
1802 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1803 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1804 perf_event__id_header_size(event);
1807 * Sum the lot; should not exceed the 64k limit we have on records.
1808 * Conservative limit to allow for callchains and other variable fields.
1810 if (event->read_size + event->header_size +
1811 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1817 static void perf_group_attach(struct perf_event *event)
1819 struct perf_event *group_leader = event->group_leader, *pos;
1821 lockdep_assert_held(&event->ctx->lock);
1824 * We can have double attach due to group movement in perf_event_open.
1826 if (event->attach_state & PERF_ATTACH_GROUP)
1829 event->attach_state |= PERF_ATTACH_GROUP;
1831 if (group_leader == event)
1834 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1836 group_leader->group_caps &= event->event_caps;
1838 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1839 group_leader->nr_siblings++;
1841 perf_event__header_size(group_leader);
1843 for_each_sibling_event(pos, group_leader)
1844 perf_event__header_size(pos);
1848 * Remove an event from the lists for its context.
1849 * Must be called with ctx->mutex and ctx->lock held.
1852 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1854 WARN_ON_ONCE(event->ctx != ctx);
1855 lockdep_assert_held(&ctx->lock);
1858 * We can have double detach due to exit/hot-unplug + close.
1860 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1863 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1865 list_update_cgroup_event(event, ctx, false);
1868 if (event->attr.inherit_stat)
1871 list_del_rcu(&event->event_entry);
1873 if (event->group_leader == event)
1874 del_event_from_groups(event, ctx);
1877 * If event was in error state, then keep it
1878 * that way, otherwise bogus counts will be
1879 * returned on read(). The only way to get out
1880 * of error state is by explicit re-enabling
1883 if (event->state > PERF_EVENT_STATE_OFF)
1884 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
1889 static void perf_group_detach(struct perf_event *event)
1891 struct perf_event *sibling, *tmp;
1892 struct perf_event_context *ctx = event->ctx;
1894 lockdep_assert_held(&ctx->lock);
1897 * We can have double detach due to exit/hot-unplug + close.
1899 if (!(event->attach_state & PERF_ATTACH_GROUP))
1902 event->attach_state &= ~PERF_ATTACH_GROUP;
1905 * If this is a sibling, remove it from its group.
1907 if (event->group_leader != event) {
1908 list_del_init(&event->sibling_list);
1909 event->group_leader->nr_siblings--;
1914 * If this was a group event with sibling events then
1915 * upgrade the siblings to singleton events by adding them
1916 * to whatever list we are on.
1918 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
1920 sibling->group_leader = sibling;
1921 list_del_init(&sibling->sibling_list);
1923 /* Inherit group flags from the previous leader */
1924 sibling->group_caps = event->group_caps;
1926 if (!RB_EMPTY_NODE(&event->group_node)) {
1927 add_event_to_groups(sibling, event->ctx);
1929 if (sibling->state == PERF_EVENT_STATE_ACTIVE) {
1930 struct list_head *list = sibling->attr.pinned ?
1931 &ctx->pinned_active : &ctx->flexible_active;
1933 list_add_tail(&sibling->active_list, list);
1937 WARN_ON_ONCE(sibling->ctx != event->ctx);
1941 perf_event__header_size(event->group_leader);
1943 for_each_sibling_event(tmp, event->group_leader)
1944 perf_event__header_size(tmp);
1947 static bool is_orphaned_event(struct perf_event *event)
1949 return event->state == PERF_EVENT_STATE_DEAD;
1952 static inline int __pmu_filter_match(struct perf_event *event)
1954 struct pmu *pmu = event->pmu;
1955 return pmu->filter_match ? pmu->filter_match(event) : 1;
1959 * Check whether we should attempt to schedule an event group based on
1960 * PMU-specific filtering. An event group can consist of HW and SW events,
1961 * potentially with a SW leader, so we must check all the filters, to
1962 * determine whether a group is schedulable:
1964 static inline int pmu_filter_match(struct perf_event *event)
1966 struct perf_event *sibling;
1968 if (!__pmu_filter_match(event))
1971 for_each_sibling_event(sibling, event) {
1972 if (!__pmu_filter_match(sibling))
1980 event_filter_match(struct perf_event *event)
1982 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1983 perf_cgroup_match(event) && pmu_filter_match(event);
1987 event_sched_out(struct perf_event *event,
1988 struct perf_cpu_context *cpuctx,
1989 struct perf_event_context *ctx)
1991 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
1993 WARN_ON_ONCE(event->ctx != ctx);
1994 lockdep_assert_held(&ctx->lock);
1996 if (event->state != PERF_EVENT_STATE_ACTIVE)
2000 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2001 * we can schedule events _OUT_ individually through things like
2002 * __perf_remove_from_context().
2004 list_del_init(&event->active_list);
2006 perf_pmu_disable(event->pmu);
2008 event->pmu->del(event, 0);
2011 if (READ_ONCE(event->pending_disable) >= 0) {
2012 WRITE_ONCE(event->pending_disable, -1);
2013 state = PERF_EVENT_STATE_OFF;
2015 perf_event_set_state(event, state);
2017 if (!is_software_event(event))
2018 cpuctx->active_oncpu--;
2019 if (!--ctx->nr_active)
2020 perf_event_ctx_deactivate(ctx);
2021 if (event->attr.freq && event->attr.sample_freq)
2023 if (event->attr.exclusive || !cpuctx->active_oncpu)
2024 cpuctx->exclusive = 0;
2026 perf_pmu_enable(event->pmu);
2030 group_sched_out(struct perf_event *group_event,
2031 struct perf_cpu_context *cpuctx,
2032 struct perf_event_context *ctx)
2034 struct perf_event *event;
2036 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2039 perf_pmu_disable(ctx->pmu);
2041 event_sched_out(group_event, cpuctx, ctx);
2044 * Schedule out siblings (if any):
2046 for_each_sibling_event(event, group_event)
2047 event_sched_out(event, cpuctx, ctx);
2049 perf_pmu_enable(ctx->pmu);
2051 if (group_event->attr.exclusive)
2052 cpuctx->exclusive = 0;
2055 #define DETACH_GROUP 0x01UL
2058 * Cross CPU call to remove a performance event
2060 * We disable the event on the hardware level first. After that we
2061 * remove it from the context list.
2064 __perf_remove_from_context(struct perf_event *event,
2065 struct perf_cpu_context *cpuctx,
2066 struct perf_event_context *ctx,
2069 unsigned long flags = (unsigned long)info;
2071 if (ctx->is_active & EVENT_TIME) {
2072 update_context_time(ctx);
2073 update_cgrp_time_from_cpuctx(cpuctx);
2076 event_sched_out(event, cpuctx, ctx);
2077 if (flags & DETACH_GROUP)
2078 perf_group_detach(event);
2079 list_del_event(event, ctx);
2081 if (!ctx->nr_events && ctx->is_active) {
2084 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2085 cpuctx->task_ctx = NULL;
2091 * Remove the event from a task's (or a CPU's) list of events.
2093 * If event->ctx is a cloned context, callers must make sure that
2094 * every task struct that event->ctx->task could possibly point to
2095 * remains valid. This is OK when called from perf_release since
2096 * that only calls us on the top-level context, which can't be a clone.
2097 * When called from perf_event_exit_task, it's OK because the
2098 * context has been detached from its task.
2100 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2102 struct perf_event_context *ctx = event->ctx;
2104 lockdep_assert_held(&ctx->mutex);
2106 event_function_call(event, __perf_remove_from_context, (void *)flags);
2109 * The above event_function_call() can NO-OP when it hits
2110 * TASK_TOMBSTONE. In that case we must already have been detached
2111 * from the context (by perf_event_exit_event()) but the grouping
2112 * might still be in-tact.
2114 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
2115 if ((flags & DETACH_GROUP) &&
2116 (event->attach_state & PERF_ATTACH_GROUP)) {
2118 * Since in that case we cannot possibly be scheduled, simply
2121 raw_spin_lock_irq(&ctx->lock);
2122 perf_group_detach(event);
2123 raw_spin_unlock_irq(&ctx->lock);
2128 * Cross CPU call to disable a performance event
2130 static void __perf_event_disable(struct perf_event *event,
2131 struct perf_cpu_context *cpuctx,
2132 struct perf_event_context *ctx,
2135 if (event->state < PERF_EVENT_STATE_INACTIVE)
2138 if (ctx->is_active & EVENT_TIME) {
2139 update_context_time(ctx);
2140 update_cgrp_time_from_event(event);
2143 if (event == event->group_leader)
2144 group_sched_out(event, cpuctx, ctx);
2146 event_sched_out(event, cpuctx, ctx);
2148 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2154 * If event->ctx is a cloned context, callers must make sure that
2155 * every task struct that event->ctx->task could possibly point to
2156 * remains valid. This condition is satisifed when called through
2157 * perf_event_for_each_child or perf_event_for_each because they
2158 * hold the top-level event's child_mutex, so any descendant that
2159 * goes to exit will block in perf_event_exit_event().
2161 * When called from perf_pending_event it's OK because event->ctx
2162 * is the current context on this CPU and preemption is disabled,
2163 * hence we can't get into perf_event_task_sched_out for this context.
2165 static void _perf_event_disable(struct perf_event *event)
2167 struct perf_event_context *ctx = event->ctx;
2169 raw_spin_lock_irq(&ctx->lock);
2170 if (event->state <= PERF_EVENT_STATE_OFF) {
2171 raw_spin_unlock_irq(&ctx->lock);
2174 raw_spin_unlock_irq(&ctx->lock);
2176 event_function_call(event, __perf_event_disable, NULL);
2179 void perf_event_disable_local(struct perf_event *event)
2181 event_function_local(event, __perf_event_disable, NULL);
2185 * Strictly speaking kernel users cannot create groups and therefore this
2186 * interface does not need the perf_event_ctx_lock() magic.
2188 void perf_event_disable(struct perf_event *event)
2190 struct perf_event_context *ctx;
2192 ctx = perf_event_ctx_lock(event);
2193 _perf_event_disable(event);
2194 perf_event_ctx_unlock(event, ctx);
2196 EXPORT_SYMBOL_GPL(perf_event_disable);
2198 void perf_event_disable_inatomic(struct perf_event *event)
2200 WRITE_ONCE(event->pending_disable, smp_processor_id());
2201 /* can fail, see perf_pending_event_disable() */
2202 irq_work_queue(&event->pending);
2205 static void perf_set_shadow_time(struct perf_event *event,
2206 struct perf_event_context *ctx)
2209 * use the correct time source for the time snapshot
2211 * We could get by without this by leveraging the
2212 * fact that to get to this function, the caller
2213 * has most likely already called update_context_time()
2214 * and update_cgrp_time_xx() and thus both timestamp
2215 * are identical (or very close). Given that tstamp is,
2216 * already adjusted for cgroup, we could say that:
2217 * tstamp - ctx->timestamp
2219 * tstamp - cgrp->timestamp.
2221 * Then, in perf_output_read(), the calculation would
2222 * work with no changes because:
2223 * - event is guaranteed scheduled in
2224 * - no scheduled out in between
2225 * - thus the timestamp would be the same
2227 * But this is a bit hairy.
2229 * So instead, we have an explicit cgroup call to remain
2230 * within the time time source all along. We believe it
2231 * is cleaner and simpler to understand.
2233 if (is_cgroup_event(event))
2234 perf_cgroup_set_shadow_time(event, event->tstamp);
2236 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2239 #define MAX_INTERRUPTS (~0ULL)
2241 static void perf_log_throttle(struct perf_event *event, int enable);
2242 static void perf_log_itrace_start(struct perf_event *event);
2245 event_sched_in(struct perf_event *event,
2246 struct perf_cpu_context *cpuctx,
2247 struct perf_event_context *ctx)
2251 lockdep_assert_held(&ctx->lock);
2253 if (event->state <= PERF_EVENT_STATE_OFF)
2256 WRITE_ONCE(event->oncpu, smp_processor_id());
2258 * Order event::oncpu write to happen before the ACTIVE state is
2259 * visible. This allows perf_event_{stop,read}() to observe the correct
2260 * ->oncpu if it sees ACTIVE.
2263 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2266 * Unthrottle events, since we scheduled we might have missed several
2267 * ticks already, also for a heavily scheduling task there is little
2268 * guarantee it'll get a tick in a timely manner.
2270 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2271 perf_log_throttle(event, 1);
2272 event->hw.interrupts = 0;
2275 perf_pmu_disable(event->pmu);
2277 perf_set_shadow_time(event, ctx);
2279 perf_log_itrace_start(event);
2281 if (event->pmu->add(event, PERF_EF_START)) {
2282 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2288 if (!is_software_event(event))
2289 cpuctx->active_oncpu++;
2290 if (!ctx->nr_active++)
2291 perf_event_ctx_activate(ctx);
2292 if (event->attr.freq && event->attr.sample_freq)
2295 if (event->attr.exclusive)
2296 cpuctx->exclusive = 1;
2299 perf_pmu_enable(event->pmu);
2305 group_sched_in(struct perf_event *group_event,
2306 struct perf_cpu_context *cpuctx,
2307 struct perf_event_context *ctx)
2309 struct perf_event *event, *partial_group = NULL;
2310 struct pmu *pmu = ctx->pmu;
2312 if (group_event->state == PERF_EVENT_STATE_OFF)
2315 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2317 if (event_sched_in(group_event, cpuctx, ctx)) {
2318 pmu->cancel_txn(pmu);
2319 perf_mux_hrtimer_restart(cpuctx);
2324 * Schedule in siblings as one group (if any):
2326 for_each_sibling_event(event, group_event) {
2327 if (event_sched_in(event, cpuctx, ctx)) {
2328 partial_group = event;
2333 if (!pmu->commit_txn(pmu))
2338 * Groups can be scheduled in as one unit only, so undo any
2339 * partial group before returning:
2340 * The events up to the failed event are scheduled out normally.
2342 for_each_sibling_event(event, group_event) {
2343 if (event == partial_group)
2346 event_sched_out(event, cpuctx, ctx);
2348 event_sched_out(group_event, cpuctx, ctx);
2350 pmu->cancel_txn(pmu);
2352 perf_mux_hrtimer_restart(cpuctx);
2358 * Work out whether we can put this event group on the CPU now.
2360 static int group_can_go_on(struct perf_event *event,
2361 struct perf_cpu_context *cpuctx,
2365 * Groups consisting entirely of software events can always go on.
2367 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2370 * If an exclusive group is already on, no other hardware
2373 if (cpuctx->exclusive)
2376 * If this group is exclusive and there are already
2377 * events on the CPU, it can't go on.
2379 if (event->attr.exclusive && cpuctx->active_oncpu)
2382 * Otherwise, try to add it if all previous groups were able
2388 static void add_event_to_ctx(struct perf_event *event,
2389 struct perf_event_context *ctx)
2391 list_add_event(event, ctx);
2392 perf_group_attach(event);
2395 static void ctx_sched_out(struct perf_event_context *ctx,
2396 struct perf_cpu_context *cpuctx,
2397 enum event_type_t event_type);
2399 ctx_sched_in(struct perf_event_context *ctx,
2400 struct perf_cpu_context *cpuctx,
2401 enum event_type_t event_type,
2402 struct task_struct *task);
2404 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2405 struct perf_event_context *ctx,
2406 enum event_type_t event_type)
2408 if (!cpuctx->task_ctx)
2411 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2414 ctx_sched_out(ctx, cpuctx, event_type);
2417 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2418 struct perf_event_context *ctx,
2419 struct task_struct *task)
2421 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2423 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2424 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2426 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2430 * We want to maintain the following priority of scheduling:
2431 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2432 * - task pinned (EVENT_PINNED)
2433 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2434 * - task flexible (EVENT_FLEXIBLE).
2436 * In order to avoid unscheduling and scheduling back in everything every
2437 * time an event is added, only do it for the groups of equal priority and
2440 * This can be called after a batch operation on task events, in which case
2441 * event_type is a bit mask of the types of events involved. For CPU events,
2442 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2444 static void ctx_resched(struct perf_cpu_context *cpuctx,
2445 struct perf_event_context *task_ctx,
2446 enum event_type_t event_type)
2448 enum event_type_t ctx_event_type;
2449 bool cpu_event = !!(event_type & EVENT_CPU);
2452 * If pinned groups are involved, flexible groups also need to be
2455 if (event_type & EVENT_PINNED)
2456 event_type |= EVENT_FLEXIBLE;
2458 ctx_event_type = event_type & EVENT_ALL;
2460 perf_pmu_disable(cpuctx->ctx.pmu);
2462 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2465 * Decide which cpu ctx groups to schedule out based on the types
2466 * of events that caused rescheduling:
2467 * - EVENT_CPU: schedule out corresponding groups;
2468 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2469 * - otherwise, do nothing more.
2472 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2473 else if (ctx_event_type & EVENT_PINNED)
2474 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2476 perf_event_sched_in(cpuctx, task_ctx, current);
2477 perf_pmu_enable(cpuctx->ctx.pmu);
2481 * Cross CPU call to install and enable a performance event
2483 * Very similar to remote_function() + event_function() but cannot assume that
2484 * things like ctx->is_active and cpuctx->task_ctx are set.
2486 static int __perf_install_in_context(void *info)
2488 struct perf_event *event = info;
2489 struct perf_event_context *ctx = event->ctx;
2490 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2491 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2492 bool reprogram = true;
2495 raw_spin_lock(&cpuctx->ctx.lock);
2497 raw_spin_lock(&ctx->lock);
2500 reprogram = (ctx->task == current);
2503 * If the task is running, it must be running on this CPU,
2504 * otherwise we cannot reprogram things.
2506 * If its not running, we don't care, ctx->lock will
2507 * serialize against it becoming runnable.
2509 if (task_curr(ctx->task) && !reprogram) {
2514 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2515 } else if (task_ctx) {
2516 raw_spin_lock(&task_ctx->lock);
2519 #ifdef CONFIG_CGROUP_PERF
2520 if (is_cgroup_event(event)) {
2522 * If the current cgroup doesn't match the event's
2523 * cgroup, we should not try to schedule it.
2525 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2526 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2527 event->cgrp->css.cgroup);
2532 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2533 add_event_to_ctx(event, ctx);
2534 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2536 add_event_to_ctx(event, ctx);
2540 perf_ctx_unlock(cpuctx, task_ctx);
2545 static bool exclusive_event_installable(struct perf_event *event,
2546 struct perf_event_context *ctx);
2549 * Attach a performance event to a context.
2551 * Very similar to event_function_call, see comment there.
2554 perf_install_in_context(struct perf_event_context *ctx,
2555 struct perf_event *event,
2558 struct task_struct *task = READ_ONCE(ctx->task);
2560 lockdep_assert_held(&ctx->mutex);
2562 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2564 if (event->cpu != -1)
2568 * Ensures that if we can observe event->ctx, both the event and ctx
2569 * will be 'complete'. See perf_iterate_sb_cpu().
2571 smp_store_release(&event->ctx, ctx);
2574 cpu_function_call(cpu, __perf_install_in_context, event);
2579 * Should not happen, we validate the ctx is still alive before calling.
2581 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2585 * Installing events is tricky because we cannot rely on ctx->is_active
2586 * to be set in case this is the nr_events 0 -> 1 transition.
2588 * Instead we use task_curr(), which tells us if the task is running.
2589 * However, since we use task_curr() outside of rq::lock, we can race
2590 * against the actual state. This means the result can be wrong.
2592 * If we get a false positive, we retry, this is harmless.
2594 * If we get a false negative, things are complicated. If we are after
2595 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2596 * value must be correct. If we're before, it doesn't matter since
2597 * perf_event_context_sched_in() will program the counter.
2599 * However, this hinges on the remote context switch having observed
2600 * our task->perf_event_ctxp[] store, such that it will in fact take
2601 * ctx::lock in perf_event_context_sched_in().
2603 * We do this by task_function_call(), if the IPI fails to hit the task
2604 * we know any future context switch of task must see the
2605 * perf_event_ctpx[] store.
2609 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2610 * task_cpu() load, such that if the IPI then does not find the task
2611 * running, a future context switch of that task must observe the
2616 if (!task_function_call(task, __perf_install_in_context, event))
2619 raw_spin_lock_irq(&ctx->lock);
2621 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2623 * Cannot happen because we already checked above (which also
2624 * cannot happen), and we hold ctx->mutex, which serializes us
2625 * against perf_event_exit_task_context().
2627 raw_spin_unlock_irq(&ctx->lock);
2631 * If the task is not running, ctx->lock will avoid it becoming so,
2632 * thus we can safely install the event.
2634 if (task_curr(task)) {
2635 raw_spin_unlock_irq(&ctx->lock);
2638 add_event_to_ctx(event, ctx);
2639 raw_spin_unlock_irq(&ctx->lock);
2643 * Cross CPU call to enable a performance event
2645 static void __perf_event_enable(struct perf_event *event,
2646 struct perf_cpu_context *cpuctx,
2647 struct perf_event_context *ctx,
2650 struct perf_event *leader = event->group_leader;
2651 struct perf_event_context *task_ctx;
2653 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2654 event->state <= PERF_EVENT_STATE_ERROR)
2658 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2660 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2662 if (!ctx->is_active)
2665 if (!event_filter_match(event)) {
2666 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2671 * If the event is in a group and isn't the group leader,
2672 * then don't put it on unless the group is on.
2674 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2675 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2679 task_ctx = cpuctx->task_ctx;
2681 WARN_ON_ONCE(task_ctx != ctx);
2683 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2689 * If event->ctx is a cloned context, callers must make sure that
2690 * every task struct that event->ctx->task could possibly point to
2691 * remains valid. This condition is satisfied when called through
2692 * perf_event_for_each_child or perf_event_for_each as described
2693 * for perf_event_disable.
2695 static void _perf_event_enable(struct perf_event *event)
2697 struct perf_event_context *ctx = event->ctx;
2699 raw_spin_lock_irq(&ctx->lock);
2700 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2701 event->state < PERF_EVENT_STATE_ERROR) {
2702 raw_spin_unlock_irq(&ctx->lock);
2707 * If the event is in error state, clear that first.
2709 * That way, if we see the event in error state below, we know that it
2710 * has gone back into error state, as distinct from the task having
2711 * been scheduled away before the cross-call arrived.
2713 if (event->state == PERF_EVENT_STATE_ERROR)
2714 event->state = PERF_EVENT_STATE_OFF;
2715 raw_spin_unlock_irq(&ctx->lock);
2717 event_function_call(event, __perf_event_enable, NULL);
2721 * See perf_event_disable();
2723 void perf_event_enable(struct perf_event *event)
2725 struct perf_event_context *ctx;
2727 ctx = perf_event_ctx_lock(event);
2728 _perf_event_enable(event);
2729 perf_event_ctx_unlock(event, ctx);
2731 EXPORT_SYMBOL_GPL(perf_event_enable);
2733 struct stop_event_data {
2734 struct perf_event *event;
2735 unsigned int restart;
2738 static int __perf_event_stop(void *info)
2740 struct stop_event_data *sd = info;
2741 struct perf_event *event = sd->event;
2743 /* if it's already INACTIVE, do nothing */
2744 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2747 /* matches smp_wmb() in event_sched_in() */
2751 * There is a window with interrupts enabled before we get here,
2752 * so we need to check again lest we try to stop another CPU's event.
2754 if (READ_ONCE(event->oncpu) != smp_processor_id())
2757 event->pmu->stop(event, PERF_EF_UPDATE);
2760 * May race with the actual stop (through perf_pmu_output_stop()),
2761 * but it is only used for events with AUX ring buffer, and such
2762 * events will refuse to restart because of rb::aux_mmap_count==0,
2763 * see comments in perf_aux_output_begin().
2765 * Since this is happening on an event-local CPU, no trace is lost
2769 event->pmu->start(event, 0);
2774 static int perf_event_stop(struct perf_event *event, int restart)
2776 struct stop_event_data sd = {
2783 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2786 /* matches smp_wmb() in event_sched_in() */
2790 * We only want to restart ACTIVE events, so if the event goes
2791 * inactive here (event->oncpu==-1), there's nothing more to do;
2792 * fall through with ret==-ENXIO.
2794 ret = cpu_function_call(READ_ONCE(event->oncpu),
2795 __perf_event_stop, &sd);
2796 } while (ret == -EAGAIN);
2802 * In order to contain the amount of racy and tricky in the address filter
2803 * configuration management, it is a two part process:
2805 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2806 * we update the addresses of corresponding vmas in
2807 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2808 * (p2) when an event is scheduled in (pmu::add), it calls
2809 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2810 * if the generation has changed since the previous call.
2812 * If (p1) happens while the event is active, we restart it to force (p2).
2814 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2815 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2817 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2818 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2820 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2823 void perf_event_addr_filters_sync(struct perf_event *event)
2825 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2827 if (!has_addr_filter(event))
2830 raw_spin_lock(&ifh->lock);
2831 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2832 event->pmu->addr_filters_sync(event);
2833 event->hw.addr_filters_gen = event->addr_filters_gen;
2835 raw_spin_unlock(&ifh->lock);
2837 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2839 static int _perf_event_refresh(struct perf_event *event, int refresh)
2842 * not supported on inherited events
2844 if (event->attr.inherit || !is_sampling_event(event))
2847 atomic_add(refresh, &event->event_limit);
2848 _perf_event_enable(event);
2854 * See perf_event_disable()
2856 int perf_event_refresh(struct perf_event *event, int refresh)
2858 struct perf_event_context *ctx;
2861 ctx = perf_event_ctx_lock(event);
2862 ret = _perf_event_refresh(event, refresh);
2863 perf_event_ctx_unlock(event, ctx);
2867 EXPORT_SYMBOL_GPL(perf_event_refresh);
2869 static int perf_event_modify_breakpoint(struct perf_event *bp,
2870 struct perf_event_attr *attr)
2874 _perf_event_disable(bp);
2876 err = modify_user_hw_breakpoint_check(bp, attr, true);
2878 if (!bp->attr.disabled)
2879 _perf_event_enable(bp);
2884 static int perf_event_modify_attr(struct perf_event *event,
2885 struct perf_event_attr *attr)
2887 if (event->attr.type != attr->type)
2890 switch (event->attr.type) {
2891 case PERF_TYPE_BREAKPOINT:
2892 return perf_event_modify_breakpoint(event, attr);
2894 /* Place holder for future additions. */
2899 static void ctx_sched_out(struct perf_event_context *ctx,
2900 struct perf_cpu_context *cpuctx,
2901 enum event_type_t event_type)
2903 struct perf_event *event, *tmp;
2904 int is_active = ctx->is_active;
2906 lockdep_assert_held(&ctx->lock);
2908 if (likely(!ctx->nr_events)) {
2910 * See __perf_remove_from_context().
2912 WARN_ON_ONCE(ctx->is_active);
2914 WARN_ON_ONCE(cpuctx->task_ctx);
2918 ctx->is_active &= ~event_type;
2919 if (!(ctx->is_active & EVENT_ALL))
2923 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2924 if (!ctx->is_active)
2925 cpuctx->task_ctx = NULL;
2929 * Always update time if it was set; not only when it changes.
2930 * Otherwise we can 'forget' to update time for any but the last
2931 * context we sched out. For example:
2933 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2934 * ctx_sched_out(.event_type = EVENT_PINNED)
2936 * would only update time for the pinned events.
2938 if (is_active & EVENT_TIME) {
2939 /* update (and stop) ctx time */
2940 update_context_time(ctx);
2941 update_cgrp_time_from_cpuctx(cpuctx);
2944 is_active ^= ctx->is_active; /* changed bits */
2946 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2949 perf_pmu_disable(ctx->pmu);
2950 if (is_active & EVENT_PINNED) {
2951 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
2952 group_sched_out(event, cpuctx, ctx);
2955 if (is_active & EVENT_FLEXIBLE) {
2956 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
2957 group_sched_out(event, cpuctx, ctx);
2959 perf_pmu_enable(ctx->pmu);
2963 * Test whether two contexts are equivalent, i.e. whether they have both been
2964 * cloned from the same version of the same context.
2966 * Equivalence is measured using a generation number in the context that is
2967 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2968 * and list_del_event().
2970 static int context_equiv(struct perf_event_context *ctx1,
2971 struct perf_event_context *ctx2)
2973 lockdep_assert_held(&ctx1->lock);
2974 lockdep_assert_held(&ctx2->lock);
2976 /* Pinning disables the swap optimization */
2977 if (ctx1->pin_count || ctx2->pin_count)
2980 /* If ctx1 is the parent of ctx2 */
2981 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2984 /* If ctx2 is the parent of ctx1 */
2985 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2989 * If ctx1 and ctx2 have the same parent; we flatten the parent
2990 * hierarchy, see perf_event_init_context().
2992 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2993 ctx1->parent_gen == ctx2->parent_gen)
3000 static void __perf_event_sync_stat(struct perf_event *event,
3001 struct perf_event *next_event)
3005 if (!event->attr.inherit_stat)
3009 * Update the event value, we cannot use perf_event_read()
3010 * because we're in the middle of a context switch and have IRQs
3011 * disabled, which upsets smp_call_function_single(), however
3012 * we know the event must be on the current CPU, therefore we
3013 * don't need to use it.
3015 if (event->state == PERF_EVENT_STATE_ACTIVE)
3016 event->pmu->read(event);
3018 perf_event_update_time(event);
3021 * In order to keep per-task stats reliable we need to flip the event
3022 * values when we flip the contexts.
3024 value = local64_read(&next_event->count);
3025 value = local64_xchg(&event->count, value);
3026 local64_set(&next_event->count, value);
3028 swap(event->total_time_enabled, next_event->total_time_enabled);
3029 swap(event->total_time_running, next_event->total_time_running);
3032 * Since we swizzled the values, update the user visible data too.
3034 perf_event_update_userpage(event);
3035 perf_event_update_userpage(next_event);
3038 static void perf_event_sync_stat(struct perf_event_context *ctx,
3039 struct perf_event_context *next_ctx)
3041 struct perf_event *event, *next_event;
3046 update_context_time(ctx);
3048 event = list_first_entry(&ctx->event_list,
3049 struct perf_event, event_entry);
3051 next_event = list_first_entry(&next_ctx->event_list,
3052 struct perf_event, event_entry);
3054 while (&event->event_entry != &ctx->event_list &&
3055 &next_event->event_entry != &next_ctx->event_list) {
3057 __perf_event_sync_stat(event, next_event);
3059 event = list_next_entry(event, event_entry);
3060 next_event = list_next_entry(next_event, event_entry);
3064 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3065 struct task_struct *next)
3067 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3068 struct perf_event_context *next_ctx;
3069 struct perf_event_context *parent, *next_parent;
3070 struct perf_cpu_context *cpuctx;
3076 cpuctx = __get_cpu_context(ctx);
3077 if (!cpuctx->task_ctx)
3081 next_ctx = next->perf_event_ctxp[ctxn];
3085 parent = rcu_dereference(ctx->parent_ctx);
3086 next_parent = rcu_dereference(next_ctx->parent_ctx);
3088 /* If neither context have a parent context; they cannot be clones. */
3089 if (!parent && !next_parent)
3092 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3094 * Looks like the two contexts are clones, so we might be
3095 * able to optimize the context switch. We lock both
3096 * contexts and check that they are clones under the
3097 * lock (including re-checking that neither has been
3098 * uncloned in the meantime). It doesn't matter which
3099 * order we take the locks because no other cpu could
3100 * be trying to lock both of these tasks.
3102 raw_spin_lock(&ctx->lock);
3103 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3104 if (context_equiv(ctx, next_ctx)) {
3105 WRITE_ONCE(ctx->task, next);
3106 WRITE_ONCE(next_ctx->task, task);
3108 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3111 * RCU_INIT_POINTER here is safe because we've not
3112 * modified the ctx and the above modification of
3113 * ctx->task and ctx->task_ctx_data are immaterial
3114 * since those values are always verified under
3115 * ctx->lock which we're now holding.
3117 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3118 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3122 perf_event_sync_stat(ctx, next_ctx);
3124 raw_spin_unlock(&next_ctx->lock);
3125 raw_spin_unlock(&ctx->lock);
3131 raw_spin_lock(&ctx->lock);
3132 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3133 raw_spin_unlock(&ctx->lock);
3137 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3139 void perf_sched_cb_dec(struct pmu *pmu)
3141 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3143 this_cpu_dec(perf_sched_cb_usages);
3145 if (!--cpuctx->sched_cb_usage)
3146 list_del(&cpuctx->sched_cb_entry);
3150 void perf_sched_cb_inc(struct pmu *pmu)
3152 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3154 if (!cpuctx->sched_cb_usage++)
3155 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3157 this_cpu_inc(perf_sched_cb_usages);
3161 * This function provides the context switch callback to the lower code
3162 * layer. It is invoked ONLY when the context switch callback is enabled.
3164 * This callback is relevant even to per-cpu events; for example multi event
3165 * PEBS requires this to provide PID/TID information. This requires we flush
3166 * all queued PEBS records before we context switch to a new task.
3168 static void perf_pmu_sched_task(struct task_struct *prev,
3169 struct task_struct *next,
3172 struct perf_cpu_context *cpuctx;
3178 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3179 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3181 if (WARN_ON_ONCE(!pmu->sched_task))
3184 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3185 perf_pmu_disable(pmu);
3187 pmu->sched_task(cpuctx->task_ctx, sched_in);
3189 perf_pmu_enable(pmu);
3190 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3194 static void perf_event_switch(struct task_struct *task,
3195 struct task_struct *next_prev, bool sched_in);
3197 #define for_each_task_context_nr(ctxn) \
3198 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3201 * Called from scheduler to remove the events of the current task,
3202 * with interrupts disabled.
3204 * We stop each event and update the event value in event->count.
3206 * This does not protect us against NMI, but disable()
3207 * sets the disabled bit in the control field of event _before_
3208 * accessing the event control register. If a NMI hits, then it will
3209 * not restart the event.
3211 void __perf_event_task_sched_out(struct task_struct *task,
3212 struct task_struct *next)
3216 if (__this_cpu_read(perf_sched_cb_usages))
3217 perf_pmu_sched_task(task, next, false);
3219 if (atomic_read(&nr_switch_events))
3220 perf_event_switch(task, next, false);
3222 for_each_task_context_nr(ctxn)
3223 perf_event_context_sched_out(task, ctxn, next);
3226 * if cgroup events exist on this CPU, then we need
3227 * to check if we have to switch out PMU state.
3228 * cgroup event are system-wide mode only
3230 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3231 perf_cgroup_sched_out(task, next);
3235 * Called with IRQs disabled
3237 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3238 enum event_type_t event_type)
3240 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3243 static int visit_groups_merge(struct perf_event_groups *groups, int cpu,
3244 int (*func)(struct perf_event *, void *), void *data)
3246 struct perf_event **evt, *evt1, *evt2;
3249 evt1 = perf_event_groups_first(groups, -1);
3250 evt2 = perf_event_groups_first(groups, cpu);
3252 while (evt1 || evt2) {
3254 if (evt1->group_index < evt2->group_index)
3264 ret = func(*evt, data);
3268 *evt = perf_event_groups_next(*evt);
3274 struct sched_in_data {
3275 struct perf_event_context *ctx;
3276 struct perf_cpu_context *cpuctx;
3280 static int pinned_sched_in(struct perf_event *event, void *data)
3282 struct sched_in_data *sid = data;
3284 if (event->state <= PERF_EVENT_STATE_OFF)
3287 if (!event_filter_match(event))
3290 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3291 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3292 list_add_tail(&event->active_list, &sid->ctx->pinned_active);
3296 * If this pinned group hasn't been scheduled,
3297 * put it in error state.
3299 if (event->state == PERF_EVENT_STATE_INACTIVE)
3300 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3305 static int flexible_sched_in(struct perf_event *event, void *data)
3307 struct sched_in_data *sid = data;
3309 if (event->state <= PERF_EVENT_STATE_OFF)
3312 if (!event_filter_match(event))
3315 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3316 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3317 list_add_tail(&event->active_list, &sid->ctx->flexible_active);
3319 sid->can_add_hw = 0;
3326 ctx_pinned_sched_in(struct perf_event_context *ctx,
3327 struct perf_cpu_context *cpuctx)
3329 struct sched_in_data sid = {
3335 visit_groups_merge(&ctx->pinned_groups,
3337 pinned_sched_in, &sid);
3341 ctx_flexible_sched_in(struct perf_event_context *ctx,
3342 struct perf_cpu_context *cpuctx)
3344 struct sched_in_data sid = {
3350 visit_groups_merge(&ctx->flexible_groups,
3352 flexible_sched_in, &sid);
3356 ctx_sched_in(struct perf_event_context *ctx,
3357 struct perf_cpu_context *cpuctx,
3358 enum event_type_t event_type,
3359 struct task_struct *task)
3361 int is_active = ctx->is_active;
3364 lockdep_assert_held(&ctx->lock);
3366 if (likely(!ctx->nr_events))
3369 ctx->is_active |= (event_type | EVENT_TIME);
3372 cpuctx->task_ctx = ctx;
3374 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3377 is_active ^= ctx->is_active; /* changed bits */
3379 if (is_active & EVENT_TIME) {
3380 /* start ctx time */
3382 ctx->timestamp = now;
3383 perf_cgroup_set_timestamp(task, ctx);
3387 * First go through the list and put on any pinned groups
3388 * in order to give them the best chance of going on.
3390 if (is_active & EVENT_PINNED)
3391 ctx_pinned_sched_in(ctx, cpuctx);
3393 /* Then walk through the lower prio flexible groups */
3394 if (is_active & EVENT_FLEXIBLE)
3395 ctx_flexible_sched_in(ctx, cpuctx);
3398 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3399 enum event_type_t event_type,
3400 struct task_struct *task)
3402 struct perf_event_context *ctx = &cpuctx->ctx;
3404 ctx_sched_in(ctx, cpuctx, event_type, task);
3407 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3408 struct task_struct *task)
3410 struct perf_cpu_context *cpuctx;
3412 cpuctx = __get_cpu_context(ctx);
3413 if (cpuctx->task_ctx == ctx)
3416 perf_ctx_lock(cpuctx, ctx);
3418 * We must check ctx->nr_events while holding ctx->lock, such
3419 * that we serialize against perf_install_in_context().
3421 if (!ctx->nr_events)
3424 perf_pmu_disable(ctx->pmu);
3426 * We want to keep the following priority order:
3427 * cpu pinned (that don't need to move), task pinned,
3428 * cpu flexible, task flexible.
3430 * However, if task's ctx is not carrying any pinned
3431 * events, no need to flip the cpuctx's events around.
3433 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3434 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3435 perf_event_sched_in(cpuctx, ctx, task);
3436 perf_pmu_enable(ctx->pmu);
3439 perf_ctx_unlock(cpuctx, ctx);
3443 * Called from scheduler to add the events of the current task
3444 * with interrupts disabled.
3446 * We restore the event value and then enable it.
3448 * This does not protect us against NMI, but enable()
3449 * sets the enabled bit in the control field of event _before_
3450 * accessing the event control register. If a NMI hits, then it will
3451 * keep the event running.
3453 void __perf_event_task_sched_in(struct task_struct *prev,
3454 struct task_struct *task)
3456 struct perf_event_context *ctx;
3460 * If cgroup events exist on this CPU, then we need to check if we have
3461 * to switch in PMU state; cgroup event are system-wide mode only.
3463 * Since cgroup events are CPU events, we must schedule these in before
3464 * we schedule in the task events.
3466 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3467 perf_cgroup_sched_in(prev, task);
3469 for_each_task_context_nr(ctxn) {
3470 ctx = task->perf_event_ctxp[ctxn];
3474 perf_event_context_sched_in(ctx, task);
3477 if (atomic_read(&nr_switch_events))
3478 perf_event_switch(task, prev, true);
3480 if (__this_cpu_read(perf_sched_cb_usages))
3481 perf_pmu_sched_task(prev, task, true);
3484 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3486 u64 frequency = event->attr.sample_freq;
3487 u64 sec = NSEC_PER_SEC;
3488 u64 divisor, dividend;
3490 int count_fls, nsec_fls, frequency_fls, sec_fls;
3492 count_fls = fls64(count);
3493 nsec_fls = fls64(nsec);
3494 frequency_fls = fls64(frequency);
3498 * We got @count in @nsec, with a target of sample_freq HZ
3499 * the target period becomes:
3502 * period = -------------------
3503 * @nsec * sample_freq
3508 * Reduce accuracy by one bit such that @a and @b converge
3509 * to a similar magnitude.
3511 #define REDUCE_FLS(a, b) \
3513 if (a##_fls > b##_fls) { \
3523 * Reduce accuracy until either term fits in a u64, then proceed with
3524 * the other, so that finally we can do a u64/u64 division.
3526 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3527 REDUCE_FLS(nsec, frequency);
3528 REDUCE_FLS(sec, count);
3531 if (count_fls + sec_fls > 64) {
3532 divisor = nsec * frequency;
3534 while (count_fls + sec_fls > 64) {
3535 REDUCE_FLS(count, sec);
3539 dividend = count * sec;
3541 dividend = count * sec;
3543 while (nsec_fls + frequency_fls > 64) {
3544 REDUCE_FLS(nsec, frequency);
3548 divisor = nsec * frequency;
3554 return div64_u64(dividend, divisor);
3557 static DEFINE_PER_CPU(int, perf_throttled_count);
3558 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3560 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3562 struct hw_perf_event *hwc = &event->hw;
3563 s64 period, sample_period;
3566 period = perf_calculate_period(event, nsec, count);
3568 delta = (s64)(period - hwc->sample_period);
3569 delta = (delta + 7) / 8; /* low pass filter */
3571 sample_period = hwc->sample_period + delta;
3576 hwc->sample_period = sample_period;
3578 if (local64_read(&hwc->period_left) > 8*sample_period) {
3580 event->pmu->stop(event, PERF_EF_UPDATE);
3582 local64_set(&hwc->period_left, 0);
3585 event->pmu->start(event, PERF_EF_RELOAD);
3590 * combine freq adjustment with unthrottling to avoid two passes over the
3591 * events. At the same time, make sure, having freq events does not change
3592 * the rate of unthrottling as that would introduce bias.
3594 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3597 struct perf_event *event;
3598 struct hw_perf_event *hwc;
3599 u64 now, period = TICK_NSEC;
3603 * only need to iterate over all events iff:
3604 * - context have events in frequency mode (needs freq adjust)
3605 * - there are events to unthrottle on this cpu
3607 if (!(ctx->nr_freq || needs_unthr))
3610 raw_spin_lock(&ctx->lock);
3611 perf_pmu_disable(ctx->pmu);
3613 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3614 if (event->state != PERF_EVENT_STATE_ACTIVE)
3617 if (!event_filter_match(event))
3620 perf_pmu_disable(event->pmu);
3624 if (hwc->interrupts == MAX_INTERRUPTS) {
3625 hwc->interrupts = 0;
3626 perf_log_throttle(event, 1);
3627 event->pmu->start(event, 0);
3630 if (!event->attr.freq || !event->attr.sample_freq)
3634 * stop the event and update event->count
3636 event->pmu->stop(event, PERF_EF_UPDATE);
3638 now = local64_read(&event->count);
3639 delta = now - hwc->freq_count_stamp;
3640 hwc->freq_count_stamp = now;
3644 * reload only if value has changed
3645 * we have stopped the event so tell that
3646 * to perf_adjust_period() to avoid stopping it
3650 perf_adjust_period(event, period, delta, false);
3652 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3654 perf_pmu_enable(event->pmu);
3657 perf_pmu_enable(ctx->pmu);
3658 raw_spin_unlock(&ctx->lock);
3662 * Move @event to the tail of the @ctx's elegible events.
3664 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
3667 * Rotate the first entry last of non-pinned groups. Rotation might be
3668 * disabled by the inheritance code.
3670 if (ctx->rotate_disable)
3673 perf_event_groups_delete(&ctx->flexible_groups, event);
3674 perf_event_groups_insert(&ctx->flexible_groups, event);
3677 static inline struct perf_event *
3678 ctx_first_active(struct perf_event_context *ctx)
3680 return list_first_entry_or_null(&ctx->flexible_active,
3681 struct perf_event, active_list);
3684 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
3686 struct perf_event *cpu_event = NULL, *task_event = NULL;
3687 bool cpu_rotate = false, task_rotate = false;
3688 struct perf_event_context *ctx = NULL;
3691 * Since we run this from IRQ context, nobody can install new
3692 * events, thus the event count values are stable.
3695 if (cpuctx->ctx.nr_events) {
3696 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3700 ctx = cpuctx->task_ctx;
3701 if (ctx && ctx->nr_events) {
3702 if (ctx->nr_events != ctx->nr_active)
3706 if (!(cpu_rotate || task_rotate))
3709 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3710 perf_pmu_disable(cpuctx->ctx.pmu);
3713 task_event = ctx_first_active(ctx);
3715 cpu_event = ctx_first_active(&cpuctx->ctx);
3718 * As per the order given at ctx_resched() first 'pop' task flexible
3719 * and then, if needed CPU flexible.
3721 if (task_event || (ctx && cpu_event))
3722 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3724 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3727 rotate_ctx(ctx, task_event);
3729 rotate_ctx(&cpuctx->ctx, cpu_event);
3731 perf_event_sched_in(cpuctx, ctx, current);
3733 perf_pmu_enable(cpuctx->ctx.pmu);
3734 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3739 void perf_event_task_tick(void)
3741 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3742 struct perf_event_context *ctx, *tmp;
3745 lockdep_assert_irqs_disabled();
3747 __this_cpu_inc(perf_throttled_seq);
3748 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3749 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3751 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3752 perf_adjust_freq_unthr_context(ctx, throttled);
3755 static int event_enable_on_exec(struct perf_event *event,
3756 struct perf_event_context *ctx)
3758 if (!event->attr.enable_on_exec)
3761 event->attr.enable_on_exec = 0;
3762 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3765 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3771 * Enable all of a task's events that have been marked enable-on-exec.
3772 * This expects task == current.
3774 static void perf_event_enable_on_exec(int ctxn)
3776 struct perf_event_context *ctx, *clone_ctx = NULL;
3777 enum event_type_t event_type = 0;
3778 struct perf_cpu_context *cpuctx;
3779 struct perf_event *event;
3780 unsigned long flags;
3783 local_irq_save(flags);
3784 ctx = current->perf_event_ctxp[ctxn];
3785 if (!ctx || !ctx->nr_events)
3788 cpuctx = __get_cpu_context(ctx);
3789 perf_ctx_lock(cpuctx, ctx);
3790 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3791 list_for_each_entry(event, &ctx->event_list, event_entry) {
3792 enabled |= event_enable_on_exec(event, ctx);
3793 event_type |= get_event_type(event);
3797 * Unclone and reschedule this context if we enabled any event.
3800 clone_ctx = unclone_ctx(ctx);
3801 ctx_resched(cpuctx, ctx, event_type);
3803 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3805 perf_ctx_unlock(cpuctx, ctx);
3808 local_irq_restore(flags);
3814 struct perf_read_data {
3815 struct perf_event *event;
3820 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3822 u16 local_pkg, event_pkg;
3824 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3825 int local_cpu = smp_processor_id();
3827 event_pkg = topology_physical_package_id(event_cpu);
3828 local_pkg = topology_physical_package_id(local_cpu);
3830 if (event_pkg == local_pkg)
3838 * Cross CPU call to read the hardware event
3840 static void __perf_event_read(void *info)
3842 struct perf_read_data *data = info;
3843 struct perf_event *sub, *event = data->event;
3844 struct perf_event_context *ctx = event->ctx;
3845 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3846 struct pmu *pmu = event->pmu;
3849 * If this is a task context, we need to check whether it is
3850 * the current task context of this cpu. If not it has been
3851 * scheduled out before the smp call arrived. In that case
3852 * event->count would have been updated to a recent sample
3853 * when the event was scheduled out.
3855 if (ctx->task && cpuctx->task_ctx != ctx)
3858 raw_spin_lock(&ctx->lock);
3859 if (ctx->is_active & EVENT_TIME) {
3860 update_context_time(ctx);
3861 update_cgrp_time_from_event(event);
3864 perf_event_update_time(event);
3866 perf_event_update_sibling_time(event);
3868 if (event->state != PERF_EVENT_STATE_ACTIVE)
3877 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3881 for_each_sibling_event(sub, event) {
3882 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3884 * Use sibling's PMU rather than @event's since
3885 * sibling could be on different (eg: software) PMU.
3887 sub->pmu->read(sub);
3891 data->ret = pmu->commit_txn(pmu);
3894 raw_spin_unlock(&ctx->lock);
3897 static inline u64 perf_event_count(struct perf_event *event)
3899 return local64_read(&event->count) + atomic64_read(&event->child_count);
3903 * NMI-safe method to read a local event, that is an event that
3905 * - either for the current task, or for this CPU
3906 * - does not have inherit set, for inherited task events
3907 * will not be local and we cannot read them atomically
3908 * - must not have a pmu::count method
3910 int perf_event_read_local(struct perf_event *event, u64 *value,
3911 u64 *enabled, u64 *running)
3913 unsigned long flags;
3917 * Disabling interrupts avoids all counter scheduling (context
3918 * switches, timer based rotation and IPIs).
3920 local_irq_save(flags);
3923 * It must not be an event with inherit set, we cannot read
3924 * all child counters from atomic context.
3926 if (event->attr.inherit) {
3931 /* If this is a per-task event, it must be for current */
3932 if ((event->attach_state & PERF_ATTACH_TASK) &&
3933 event->hw.target != current) {
3938 /* If this is a per-CPU event, it must be for this CPU */
3939 if (!(event->attach_state & PERF_ATTACH_TASK) &&
3940 event->cpu != smp_processor_id()) {
3945 /* If this is a pinned event it must be running on this CPU */
3946 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
3952 * If the event is currently on this CPU, its either a per-task event,
3953 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3956 if (event->oncpu == smp_processor_id())
3957 event->pmu->read(event);
3959 *value = local64_read(&event->count);
3960 if (enabled || running) {
3961 u64 now = event->shadow_ctx_time + perf_clock();
3962 u64 __enabled, __running;
3964 __perf_update_times(event, now, &__enabled, &__running);
3966 *enabled = __enabled;
3968 *running = __running;
3971 local_irq_restore(flags);
3976 static int perf_event_read(struct perf_event *event, bool group)
3978 enum perf_event_state state = READ_ONCE(event->state);
3979 int event_cpu, ret = 0;
3982 * If event is enabled and currently active on a CPU, update the
3983 * value in the event structure:
3986 if (state == PERF_EVENT_STATE_ACTIVE) {
3987 struct perf_read_data data;
3990 * Orders the ->state and ->oncpu loads such that if we see
3991 * ACTIVE we must also see the right ->oncpu.
3993 * Matches the smp_wmb() from event_sched_in().
3997 event_cpu = READ_ONCE(event->oncpu);
3998 if ((unsigned)event_cpu >= nr_cpu_ids)
4001 data = (struct perf_read_data){
4008 event_cpu = __perf_event_read_cpu(event, event_cpu);
4011 * Purposely ignore the smp_call_function_single() return
4014 * If event_cpu isn't a valid CPU it means the event got
4015 * scheduled out and that will have updated the event count.
4017 * Therefore, either way, we'll have an up-to-date event count
4020 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4024 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4025 struct perf_event_context *ctx = event->ctx;
4026 unsigned long flags;
4028 raw_spin_lock_irqsave(&ctx->lock, flags);
4029 state = event->state;
4030 if (state != PERF_EVENT_STATE_INACTIVE) {
4031 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4036 * May read while context is not active (e.g., thread is
4037 * blocked), in that case we cannot update context time
4039 if (ctx->is_active & EVENT_TIME) {
4040 update_context_time(ctx);
4041 update_cgrp_time_from_event(event);
4044 perf_event_update_time(event);
4046 perf_event_update_sibling_time(event);
4047 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4054 * Initialize the perf_event context in a task_struct:
4056 static void __perf_event_init_context(struct perf_event_context *ctx)
4058 raw_spin_lock_init(&ctx->lock);
4059 mutex_init(&ctx->mutex);
4060 INIT_LIST_HEAD(&ctx->active_ctx_list);
4061 perf_event_groups_init(&ctx->pinned_groups);
4062 perf_event_groups_init(&ctx->flexible_groups);
4063 INIT_LIST_HEAD(&ctx->event_list);
4064 INIT_LIST_HEAD(&ctx->pinned_active);
4065 INIT_LIST_HEAD(&ctx->flexible_active);
4066 atomic_set(&ctx->refcount, 1);
4069 static struct perf_event_context *
4070 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4072 struct perf_event_context *ctx;
4074 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4078 __perf_event_init_context(ctx);
4081 get_task_struct(task);
4088 static struct task_struct *
4089 find_lively_task_by_vpid(pid_t vpid)
4091 struct task_struct *task;
4097 task = find_task_by_vpid(vpid);
4099 get_task_struct(task);
4103 return ERR_PTR(-ESRCH);
4109 * Returns a matching context with refcount and pincount.
4111 static struct perf_event_context *
4112 find_get_context(struct pmu *pmu, struct task_struct *task,
4113 struct perf_event *event)
4115 struct perf_event_context *ctx, *clone_ctx = NULL;
4116 struct perf_cpu_context *cpuctx;
4117 void *task_ctx_data = NULL;
4118 unsigned long flags;
4120 int cpu = event->cpu;
4123 /* Must be root to operate on a CPU event: */
4124 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
4125 return ERR_PTR(-EACCES);
4127 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4136 ctxn = pmu->task_ctx_nr;
4140 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4141 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
4142 if (!task_ctx_data) {
4149 ctx = perf_lock_task_context(task, ctxn, &flags);
4151 clone_ctx = unclone_ctx(ctx);
4154 if (task_ctx_data && !ctx->task_ctx_data) {
4155 ctx->task_ctx_data = task_ctx_data;
4156 task_ctx_data = NULL;
4158 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4163 ctx = alloc_perf_context(pmu, task);
4168 if (task_ctx_data) {
4169 ctx->task_ctx_data = task_ctx_data;
4170 task_ctx_data = NULL;
4174 mutex_lock(&task->perf_event_mutex);
4176 * If it has already passed perf_event_exit_task().
4177 * we must see PF_EXITING, it takes this mutex too.
4179 if (task->flags & PF_EXITING)
4181 else if (task->perf_event_ctxp[ctxn])
4186 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4188 mutex_unlock(&task->perf_event_mutex);
4190 if (unlikely(err)) {
4199 kfree(task_ctx_data);
4203 kfree(task_ctx_data);
4204 return ERR_PTR(err);
4207 static void perf_event_free_filter(struct perf_event *event);
4208 static void perf_event_free_bpf_prog(struct perf_event *event);
4210 static void free_event_rcu(struct rcu_head *head)
4212 struct perf_event *event;
4214 event = container_of(head, struct perf_event, rcu_head);
4216 put_pid_ns(event->ns);
4217 perf_event_free_filter(event);
4221 static void ring_buffer_attach(struct perf_event *event,
4222 struct ring_buffer *rb);
4224 static void detach_sb_event(struct perf_event *event)
4226 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4228 raw_spin_lock(&pel->lock);
4229 list_del_rcu(&event->sb_list);
4230 raw_spin_unlock(&pel->lock);
4233 static bool is_sb_event(struct perf_event *event)
4235 struct perf_event_attr *attr = &event->attr;
4240 if (event->attach_state & PERF_ATTACH_TASK)
4243 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4244 attr->comm || attr->comm_exec ||
4246 attr->context_switch)
4251 static void unaccount_pmu_sb_event(struct perf_event *event)
4253 if (is_sb_event(event))
4254 detach_sb_event(event);
4257 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4262 if (is_cgroup_event(event))
4263 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4266 #ifdef CONFIG_NO_HZ_FULL
4267 static DEFINE_SPINLOCK(nr_freq_lock);
4270 static void unaccount_freq_event_nohz(void)
4272 #ifdef CONFIG_NO_HZ_FULL
4273 spin_lock(&nr_freq_lock);
4274 if (atomic_dec_and_test(&nr_freq_events))
4275 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4276 spin_unlock(&nr_freq_lock);
4280 static void unaccount_freq_event(void)
4282 if (tick_nohz_full_enabled())
4283 unaccount_freq_event_nohz();
4285 atomic_dec(&nr_freq_events);
4288 static void unaccount_event(struct perf_event *event)
4295 if (event->attach_state & PERF_ATTACH_TASK)
4297 if (event->attr.mmap || event->attr.mmap_data)
4298 atomic_dec(&nr_mmap_events);
4299 if (event->attr.comm)
4300 atomic_dec(&nr_comm_events);
4301 if (event->attr.namespaces)
4302 atomic_dec(&nr_namespaces_events);
4303 if (event->attr.task)
4304 atomic_dec(&nr_task_events);
4305 if (event->attr.freq)
4306 unaccount_freq_event();
4307 if (event->attr.context_switch) {
4309 atomic_dec(&nr_switch_events);
4311 if (is_cgroup_event(event))
4313 if (has_branch_stack(event))
4317 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4318 schedule_delayed_work(&perf_sched_work, HZ);
4321 unaccount_event_cpu(event, event->cpu);
4323 unaccount_pmu_sb_event(event);
4326 static void perf_sched_delayed(struct work_struct *work)
4328 mutex_lock(&perf_sched_mutex);
4329 if (atomic_dec_and_test(&perf_sched_count))
4330 static_branch_disable(&perf_sched_events);
4331 mutex_unlock(&perf_sched_mutex);
4335 * The following implement mutual exclusion of events on "exclusive" pmus
4336 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4337 * at a time, so we disallow creating events that might conflict, namely:
4339 * 1) cpu-wide events in the presence of per-task events,
4340 * 2) per-task events in the presence of cpu-wide events,
4341 * 3) two matching events on the same context.
4343 * The former two cases are handled in the allocation path (perf_event_alloc(),
4344 * _free_event()), the latter -- before the first perf_install_in_context().
4346 static int exclusive_event_init(struct perf_event *event)
4348 struct pmu *pmu = event->pmu;
4350 if (!is_exclusive_pmu(pmu))
4354 * Prevent co-existence of per-task and cpu-wide events on the
4355 * same exclusive pmu.
4357 * Negative pmu::exclusive_cnt means there are cpu-wide
4358 * events on this "exclusive" pmu, positive means there are
4361 * Since this is called in perf_event_alloc() path, event::ctx
4362 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4363 * to mean "per-task event", because unlike other attach states it
4364 * never gets cleared.
4366 if (event->attach_state & PERF_ATTACH_TASK) {
4367 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4370 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4377 static void exclusive_event_destroy(struct perf_event *event)
4379 struct pmu *pmu = event->pmu;
4381 if (!is_exclusive_pmu(pmu))
4384 /* see comment in exclusive_event_init() */
4385 if (event->attach_state & PERF_ATTACH_TASK)
4386 atomic_dec(&pmu->exclusive_cnt);
4388 atomic_inc(&pmu->exclusive_cnt);
4391 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4393 if ((e1->pmu == e2->pmu) &&
4394 (e1->cpu == e2->cpu ||
4401 static bool exclusive_event_installable(struct perf_event *event,
4402 struct perf_event_context *ctx)
4404 struct perf_event *iter_event;
4405 struct pmu *pmu = event->pmu;
4407 lockdep_assert_held(&ctx->mutex);
4409 if (!is_exclusive_pmu(pmu))
4412 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4413 if (exclusive_event_match(iter_event, event))
4420 static void perf_addr_filters_splice(struct perf_event *event,
4421 struct list_head *head);
4423 static void _free_event(struct perf_event *event)
4425 irq_work_sync(&event->pending);
4427 unaccount_event(event);
4431 * Can happen when we close an event with re-directed output.
4433 * Since we have a 0 refcount, perf_mmap_close() will skip
4434 * over us; possibly making our ring_buffer_put() the last.
4436 mutex_lock(&event->mmap_mutex);
4437 ring_buffer_attach(event, NULL);
4438 mutex_unlock(&event->mmap_mutex);
4441 if (is_cgroup_event(event))
4442 perf_detach_cgroup(event);
4444 if (!event->parent) {
4445 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4446 put_callchain_buffers();
4449 perf_event_free_bpf_prog(event);
4450 perf_addr_filters_splice(event, NULL);
4451 kfree(event->addr_filters_offs);
4454 event->destroy(event);
4457 * Must be after ->destroy(), due to uprobe_perf_close() using
4460 if (event->hw.target)
4461 put_task_struct(event->hw.target);
4464 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4465 * all task references must be cleaned up.
4468 put_ctx(event->ctx);
4470 exclusive_event_destroy(event);
4471 module_put(event->pmu->module);
4473 call_rcu(&event->rcu_head, free_event_rcu);
4477 * Used to free events which have a known refcount of 1, such as in error paths
4478 * where the event isn't exposed yet and inherited events.
4480 static void free_event(struct perf_event *event)
4482 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4483 "unexpected event refcount: %ld; ptr=%p\n",
4484 atomic_long_read(&event->refcount), event)) {
4485 /* leak to avoid use-after-free */
4493 * Remove user event from the owner task.
4495 static void perf_remove_from_owner(struct perf_event *event)
4497 struct task_struct *owner;
4501 * Matches the smp_store_release() in perf_event_exit_task(). If we
4502 * observe !owner it means the list deletion is complete and we can
4503 * indeed free this event, otherwise we need to serialize on
4504 * owner->perf_event_mutex.
4506 owner = READ_ONCE(event->owner);
4509 * Since delayed_put_task_struct() also drops the last
4510 * task reference we can safely take a new reference
4511 * while holding the rcu_read_lock().
4513 get_task_struct(owner);
4519 * If we're here through perf_event_exit_task() we're already
4520 * holding ctx->mutex which would be an inversion wrt. the
4521 * normal lock order.
4523 * However we can safely take this lock because its the child
4526 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4529 * We have to re-check the event->owner field, if it is cleared
4530 * we raced with perf_event_exit_task(), acquiring the mutex
4531 * ensured they're done, and we can proceed with freeing the
4535 list_del_init(&event->owner_entry);
4536 smp_store_release(&event->owner, NULL);
4538 mutex_unlock(&owner->perf_event_mutex);
4539 put_task_struct(owner);
4543 static void put_event(struct perf_event *event)
4545 if (!atomic_long_dec_and_test(&event->refcount))
4552 * Kill an event dead; while event:refcount will preserve the event
4553 * object, it will not preserve its functionality. Once the last 'user'
4554 * gives up the object, we'll destroy the thing.
4556 int perf_event_release_kernel(struct perf_event *event)
4558 struct perf_event_context *ctx = event->ctx;
4559 struct perf_event *child, *tmp;
4560 LIST_HEAD(free_list);
4563 * If we got here through err_file: fput(event_file); we will not have
4564 * attached to a context yet.
4567 WARN_ON_ONCE(event->attach_state &
4568 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4572 if (!is_kernel_event(event))
4573 perf_remove_from_owner(event);
4575 ctx = perf_event_ctx_lock(event);
4576 WARN_ON_ONCE(ctx->parent_ctx);
4577 perf_remove_from_context(event, DETACH_GROUP);
4579 raw_spin_lock_irq(&ctx->lock);
4581 * Mark this event as STATE_DEAD, there is no external reference to it
4584 * Anybody acquiring event->child_mutex after the below loop _must_
4585 * also see this, most importantly inherit_event() which will avoid
4586 * placing more children on the list.
4588 * Thus this guarantees that we will in fact observe and kill _ALL_
4591 event->state = PERF_EVENT_STATE_DEAD;
4592 raw_spin_unlock_irq(&ctx->lock);
4594 perf_event_ctx_unlock(event, ctx);
4597 mutex_lock(&event->child_mutex);
4598 list_for_each_entry(child, &event->child_list, child_list) {
4601 * Cannot change, child events are not migrated, see the
4602 * comment with perf_event_ctx_lock_nested().
4604 ctx = READ_ONCE(child->ctx);
4606 * Since child_mutex nests inside ctx::mutex, we must jump
4607 * through hoops. We start by grabbing a reference on the ctx.
4609 * Since the event cannot get freed while we hold the
4610 * child_mutex, the context must also exist and have a !0
4616 * Now that we have a ctx ref, we can drop child_mutex, and
4617 * acquire ctx::mutex without fear of it going away. Then we
4618 * can re-acquire child_mutex.
4620 mutex_unlock(&event->child_mutex);
4621 mutex_lock(&ctx->mutex);
4622 mutex_lock(&event->child_mutex);
4625 * Now that we hold ctx::mutex and child_mutex, revalidate our
4626 * state, if child is still the first entry, it didn't get freed
4627 * and we can continue doing so.
4629 tmp = list_first_entry_or_null(&event->child_list,
4630 struct perf_event, child_list);
4632 perf_remove_from_context(child, DETACH_GROUP);
4633 list_move(&child->child_list, &free_list);
4635 * This matches the refcount bump in inherit_event();
4636 * this can't be the last reference.
4641 mutex_unlock(&event->child_mutex);
4642 mutex_unlock(&ctx->mutex);
4646 mutex_unlock(&event->child_mutex);
4648 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4649 void *var = &child->ctx->refcount;
4651 list_del(&child->child_list);
4655 * Wake any perf_event_free_task() waiting for this event to be
4658 smp_mb(); /* pairs with wait_var_event() */
4663 put_event(event); /* Must be the 'last' reference */
4666 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4669 * Called when the last reference to the file is gone.
4671 static int perf_release(struct inode *inode, struct file *file)
4673 perf_event_release_kernel(file->private_data);
4677 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4679 struct perf_event *child;
4685 mutex_lock(&event->child_mutex);
4687 (void)perf_event_read(event, false);
4688 total += perf_event_count(event);
4690 *enabled += event->total_time_enabled +
4691 atomic64_read(&event->child_total_time_enabled);
4692 *running += event->total_time_running +
4693 atomic64_read(&event->child_total_time_running);
4695 list_for_each_entry(child, &event->child_list, child_list) {
4696 (void)perf_event_read(child, false);
4697 total += perf_event_count(child);
4698 *enabled += child->total_time_enabled;
4699 *running += child->total_time_running;
4701 mutex_unlock(&event->child_mutex);
4706 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4708 struct perf_event_context *ctx;
4711 ctx = perf_event_ctx_lock(event);
4712 count = __perf_event_read_value(event, enabled, running);
4713 perf_event_ctx_unlock(event, ctx);
4717 EXPORT_SYMBOL_GPL(perf_event_read_value);
4719 static int __perf_read_group_add(struct perf_event *leader,
4720 u64 read_format, u64 *values)
4722 struct perf_event_context *ctx = leader->ctx;
4723 struct perf_event *sub;
4724 unsigned long flags;
4725 int n = 1; /* skip @nr */
4728 ret = perf_event_read(leader, true);
4732 raw_spin_lock_irqsave(&ctx->lock, flags);
4735 * Since we co-schedule groups, {enabled,running} times of siblings
4736 * will be identical to those of the leader, so we only publish one
4739 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4740 values[n++] += leader->total_time_enabled +
4741 atomic64_read(&leader->child_total_time_enabled);
4744 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4745 values[n++] += leader->total_time_running +
4746 atomic64_read(&leader->child_total_time_running);
4750 * Write {count,id} tuples for every sibling.
4752 values[n++] += perf_event_count(leader);
4753 if (read_format & PERF_FORMAT_ID)
4754 values[n++] = primary_event_id(leader);
4756 for_each_sibling_event(sub, leader) {
4757 values[n++] += perf_event_count(sub);
4758 if (read_format & PERF_FORMAT_ID)
4759 values[n++] = primary_event_id(sub);
4762 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4766 static int perf_read_group(struct perf_event *event,
4767 u64 read_format, char __user *buf)
4769 struct perf_event *leader = event->group_leader, *child;
4770 struct perf_event_context *ctx = leader->ctx;
4774 lockdep_assert_held(&ctx->mutex);
4776 values = kzalloc(event->read_size, GFP_KERNEL);
4780 values[0] = 1 + leader->nr_siblings;
4783 * By locking the child_mutex of the leader we effectively
4784 * lock the child list of all siblings.. XXX explain how.
4786 mutex_lock(&leader->child_mutex);
4788 ret = __perf_read_group_add(leader, read_format, values);
4792 list_for_each_entry(child, &leader->child_list, child_list) {
4793 ret = __perf_read_group_add(child, read_format, values);
4798 mutex_unlock(&leader->child_mutex);
4800 ret = event->read_size;
4801 if (copy_to_user(buf, values, event->read_size))
4806 mutex_unlock(&leader->child_mutex);
4812 static int perf_read_one(struct perf_event *event,
4813 u64 read_format, char __user *buf)
4815 u64 enabled, running;
4819 values[n++] = __perf_event_read_value(event, &enabled, &running);
4820 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4821 values[n++] = enabled;
4822 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4823 values[n++] = running;
4824 if (read_format & PERF_FORMAT_ID)
4825 values[n++] = primary_event_id(event);
4827 if (copy_to_user(buf, values, n * sizeof(u64)))
4830 return n * sizeof(u64);
4833 static bool is_event_hup(struct perf_event *event)
4837 if (event->state > PERF_EVENT_STATE_EXIT)
4840 mutex_lock(&event->child_mutex);
4841 no_children = list_empty(&event->child_list);
4842 mutex_unlock(&event->child_mutex);
4847 * Read the performance event - simple non blocking version for now
4850 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4852 u64 read_format = event->attr.read_format;
4856 * Return end-of-file for a read on an event that is in
4857 * error state (i.e. because it was pinned but it couldn't be
4858 * scheduled on to the CPU at some point).
4860 if (event->state == PERF_EVENT_STATE_ERROR)
4863 if (count < event->read_size)
4866 WARN_ON_ONCE(event->ctx->parent_ctx);
4867 if (read_format & PERF_FORMAT_GROUP)
4868 ret = perf_read_group(event, read_format, buf);
4870 ret = perf_read_one(event, read_format, buf);
4876 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4878 struct perf_event *event = file->private_data;
4879 struct perf_event_context *ctx;
4882 ctx = perf_event_ctx_lock(event);
4883 ret = __perf_read(event, buf, count);
4884 perf_event_ctx_unlock(event, ctx);
4889 static __poll_t perf_poll(struct file *file, poll_table *wait)
4891 struct perf_event *event = file->private_data;
4892 struct ring_buffer *rb;
4893 __poll_t events = EPOLLHUP;
4895 poll_wait(file, &event->waitq, wait);
4897 if (is_event_hup(event))
4901 * Pin the event->rb by taking event->mmap_mutex; otherwise
4902 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4904 mutex_lock(&event->mmap_mutex);
4907 events = atomic_xchg(&rb->poll, 0);
4908 mutex_unlock(&event->mmap_mutex);
4912 static void _perf_event_reset(struct perf_event *event)
4914 (void)perf_event_read(event, false);
4915 local64_set(&event->count, 0);
4916 perf_event_update_userpage(event);
4920 * Holding the top-level event's child_mutex means that any
4921 * descendant process that has inherited this event will block
4922 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4923 * task existence requirements of perf_event_enable/disable.
4925 static void perf_event_for_each_child(struct perf_event *event,
4926 void (*func)(struct perf_event *))
4928 struct perf_event *child;
4930 WARN_ON_ONCE(event->ctx->parent_ctx);
4932 mutex_lock(&event->child_mutex);
4934 list_for_each_entry(child, &event->child_list, child_list)
4936 mutex_unlock(&event->child_mutex);
4939 static void perf_event_for_each(struct perf_event *event,
4940 void (*func)(struct perf_event *))
4942 struct perf_event_context *ctx = event->ctx;
4943 struct perf_event *sibling;
4945 lockdep_assert_held(&ctx->mutex);
4947 event = event->group_leader;
4949 perf_event_for_each_child(event, func);
4950 for_each_sibling_event(sibling, event)
4951 perf_event_for_each_child(sibling, func);
4954 static void __perf_event_period(struct perf_event *event,
4955 struct perf_cpu_context *cpuctx,
4956 struct perf_event_context *ctx,
4959 u64 value = *((u64 *)info);
4962 if (event->attr.freq) {
4963 event->attr.sample_freq = value;
4965 event->attr.sample_period = value;
4966 event->hw.sample_period = value;
4969 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4971 perf_pmu_disable(ctx->pmu);
4973 * We could be throttled; unthrottle now to avoid the tick
4974 * trying to unthrottle while we already re-started the event.
4976 if (event->hw.interrupts == MAX_INTERRUPTS) {
4977 event->hw.interrupts = 0;
4978 perf_log_throttle(event, 1);
4980 event->pmu->stop(event, PERF_EF_UPDATE);
4983 local64_set(&event->hw.period_left, 0);
4986 event->pmu->start(event, PERF_EF_RELOAD);
4987 perf_pmu_enable(ctx->pmu);
4991 static int perf_event_check_period(struct perf_event *event, u64 value)
4993 return event->pmu->check_period(event, value);
4996 static int perf_event_period(struct perf_event *event, u64 __user *arg)
5000 if (!is_sampling_event(event))
5003 if (copy_from_user(&value, arg, sizeof(value)))
5009 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5012 if (perf_event_check_period(event, value))
5015 event_function_call(event, __perf_event_period, &value);
5020 static const struct file_operations perf_fops;
5022 static inline int perf_fget_light(int fd, struct fd *p)
5024 struct fd f = fdget(fd);
5028 if (f.file->f_op != &perf_fops) {
5036 static int perf_event_set_output(struct perf_event *event,
5037 struct perf_event *output_event);
5038 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5039 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5040 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5041 struct perf_event_attr *attr);
5043 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5045 void (*func)(struct perf_event *);
5049 case PERF_EVENT_IOC_ENABLE:
5050 func = _perf_event_enable;
5052 case PERF_EVENT_IOC_DISABLE:
5053 func = _perf_event_disable;
5055 case PERF_EVENT_IOC_RESET:
5056 func = _perf_event_reset;
5059 case PERF_EVENT_IOC_REFRESH:
5060 return _perf_event_refresh(event, arg);
5062 case PERF_EVENT_IOC_PERIOD:
5063 return perf_event_period(event, (u64 __user *)arg);
5065 case PERF_EVENT_IOC_ID:
5067 u64 id = primary_event_id(event);
5069 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5074 case PERF_EVENT_IOC_SET_OUTPUT:
5078 struct perf_event *output_event;
5080 ret = perf_fget_light(arg, &output);
5083 output_event = output.file->private_data;
5084 ret = perf_event_set_output(event, output_event);
5087 ret = perf_event_set_output(event, NULL);
5092 case PERF_EVENT_IOC_SET_FILTER:
5093 return perf_event_set_filter(event, (void __user *)arg);
5095 case PERF_EVENT_IOC_SET_BPF:
5096 return perf_event_set_bpf_prog(event, arg);
5098 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5099 struct ring_buffer *rb;
5102 rb = rcu_dereference(event->rb);
5103 if (!rb || !rb->nr_pages) {
5107 rb_toggle_paused(rb, !!arg);
5112 case PERF_EVENT_IOC_QUERY_BPF:
5113 return perf_event_query_prog_array(event, (void __user *)arg);
5115 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5116 struct perf_event_attr new_attr;
5117 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5123 return perf_event_modify_attr(event, &new_attr);
5129 if (flags & PERF_IOC_FLAG_GROUP)
5130 perf_event_for_each(event, func);
5132 perf_event_for_each_child(event, func);
5137 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5139 struct perf_event *event = file->private_data;
5140 struct perf_event_context *ctx;
5143 ctx = perf_event_ctx_lock(event);
5144 ret = _perf_ioctl(event, cmd, arg);
5145 perf_event_ctx_unlock(event, ctx);
5150 #ifdef CONFIG_COMPAT
5151 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5154 switch (_IOC_NR(cmd)) {
5155 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5156 case _IOC_NR(PERF_EVENT_IOC_ID):
5157 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5158 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5159 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5160 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5161 cmd &= ~IOCSIZE_MASK;
5162 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5166 return perf_ioctl(file, cmd, arg);
5169 # define perf_compat_ioctl NULL
5172 int perf_event_task_enable(void)
5174 struct perf_event_context *ctx;
5175 struct perf_event *event;
5177 mutex_lock(¤t->perf_event_mutex);
5178 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5179 ctx = perf_event_ctx_lock(event);
5180 perf_event_for_each_child(event, _perf_event_enable);
5181 perf_event_ctx_unlock(event, ctx);
5183 mutex_unlock(¤t->perf_event_mutex);
5188 int perf_event_task_disable(void)
5190 struct perf_event_context *ctx;
5191 struct perf_event *event;
5193 mutex_lock(¤t->perf_event_mutex);
5194 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5195 ctx = perf_event_ctx_lock(event);
5196 perf_event_for_each_child(event, _perf_event_disable);
5197 perf_event_ctx_unlock(event, ctx);
5199 mutex_unlock(¤t->perf_event_mutex);
5204 static int perf_event_index(struct perf_event *event)
5206 if (event->hw.state & PERF_HES_STOPPED)
5209 if (event->state != PERF_EVENT_STATE_ACTIVE)
5212 return event->pmu->event_idx(event);
5215 static void calc_timer_values(struct perf_event *event,
5222 *now = perf_clock();
5223 ctx_time = event->shadow_ctx_time + *now;
5224 __perf_update_times(event, ctx_time, enabled, running);
5227 static void perf_event_init_userpage(struct perf_event *event)
5229 struct perf_event_mmap_page *userpg;
5230 struct ring_buffer *rb;
5233 rb = rcu_dereference(event->rb);
5237 userpg = rb->user_page;
5239 /* Allow new userspace to detect that bit 0 is deprecated */
5240 userpg->cap_bit0_is_deprecated = 1;
5241 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5242 userpg->data_offset = PAGE_SIZE;
5243 userpg->data_size = perf_data_size(rb);
5249 void __weak arch_perf_update_userpage(
5250 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5255 * Callers need to ensure there can be no nesting of this function, otherwise
5256 * the seqlock logic goes bad. We can not serialize this because the arch
5257 * code calls this from NMI context.
5259 void perf_event_update_userpage(struct perf_event *event)
5261 struct perf_event_mmap_page *userpg;
5262 struct ring_buffer *rb;
5263 u64 enabled, running, now;
5266 rb = rcu_dereference(event->rb);
5271 * compute total_time_enabled, total_time_running
5272 * based on snapshot values taken when the event
5273 * was last scheduled in.
5275 * we cannot simply called update_context_time()
5276 * because of locking issue as we can be called in
5279 calc_timer_values(event, &now, &enabled, &running);
5281 userpg = rb->user_page;
5283 * Disable preemption to guarantee consistent time stamps are stored to
5289 userpg->index = perf_event_index(event);
5290 userpg->offset = perf_event_count(event);
5292 userpg->offset -= local64_read(&event->hw.prev_count);
5294 userpg->time_enabled = enabled +
5295 atomic64_read(&event->child_total_time_enabled);
5297 userpg->time_running = running +
5298 atomic64_read(&event->child_total_time_running);
5300 arch_perf_update_userpage(event, userpg, now);
5308 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5310 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5312 struct perf_event *event = vmf->vma->vm_file->private_data;
5313 struct ring_buffer *rb;
5314 vm_fault_t ret = VM_FAULT_SIGBUS;
5316 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5317 if (vmf->pgoff == 0)
5323 rb = rcu_dereference(event->rb);
5327 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5330 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5334 get_page(vmf->page);
5335 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5336 vmf->page->index = vmf->pgoff;
5345 static void ring_buffer_attach(struct perf_event *event,
5346 struct ring_buffer *rb)
5348 struct ring_buffer *old_rb = NULL;
5349 unsigned long flags;
5353 * Should be impossible, we set this when removing
5354 * event->rb_entry and wait/clear when adding event->rb_entry.
5356 WARN_ON_ONCE(event->rcu_pending);
5359 spin_lock_irqsave(&old_rb->event_lock, flags);
5360 list_del_rcu(&event->rb_entry);
5361 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5363 event->rcu_batches = get_state_synchronize_rcu();
5364 event->rcu_pending = 1;
5368 if (event->rcu_pending) {
5369 cond_synchronize_rcu(event->rcu_batches);
5370 event->rcu_pending = 0;
5373 spin_lock_irqsave(&rb->event_lock, flags);
5374 list_add_rcu(&event->rb_entry, &rb->event_list);
5375 spin_unlock_irqrestore(&rb->event_lock, flags);
5379 * Avoid racing with perf_mmap_close(AUX): stop the event
5380 * before swizzling the event::rb pointer; if it's getting
5381 * unmapped, its aux_mmap_count will be 0 and it won't
5382 * restart. See the comment in __perf_pmu_output_stop().
5384 * Data will inevitably be lost when set_output is done in
5385 * mid-air, but then again, whoever does it like this is
5386 * not in for the data anyway.
5389 perf_event_stop(event, 0);
5391 rcu_assign_pointer(event->rb, rb);
5394 ring_buffer_put(old_rb);
5396 * Since we detached before setting the new rb, so that we
5397 * could attach the new rb, we could have missed a wakeup.
5400 wake_up_all(&event->waitq);
5404 static void ring_buffer_wakeup(struct perf_event *event)
5406 struct ring_buffer *rb;
5409 rb = rcu_dereference(event->rb);
5411 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5412 wake_up_all(&event->waitq);
5417 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5419 struct ring_buffer *rb;
5422 rb = rcu_dereference(event->rb);
5424 if (!atomic_inc_not_zero(&rb->refcount))
5432 void ring_buffer_put(struct ring_buffer *rb)
5434 if (!atomic_dec_and_test(&rb->refcount))
5437 WARN_ON_ONCE(!list_empty(&rb->event_list));
5439 call_rcu(&rb->rcu_head, rb_free_rcu);
5442 static void perf_mmap_open(struct vm_area_struct *vma)
5444 struct perf_event *event = vma->vm_file->private_data;
5446 atomic_inc(&event->mmap_count);
5447 atomic_inc(&event->rb->mmap_count);
5450 atomic_inc(&event->rb->aux_mmap_count);
5452 if (event->pmu->event_mapped)
5453 event->pmu->event_mapped(event, vma->vm_mm);
5456 static void perf_pmu_output_stop(struct perf_event *event);
5459 * A buffer can be mmap()ed multiple times; either directly through the same
5460 * event, or through other events by use of perf_event_set_output().
5462 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5463 * the buffer here, where we still have a VM context. This means we need
5464 * to detach all events redirecting to us.
5466 static void perf_mmap_close(struct vm_area_struct *vma)
5468 struct perf_event *event = vma->vm_file->private_data;
5470 struct ring_buffer *rb = ring_buffer_get(event);
5471 struct user_struct *mmap_user = rb->mmap_user;
5472 int mmap_locked = rb->mmap_locked;
5473 unsigned long size = perf_data_size(rb);
5475 if (event->pmu->event_unmapped)
5476 event->pmu->event_unmapped(event, vma->vm_mm);
5479 * rb->aux_mmap_count will always drop before rb->mmap_count and
5480 * event->mmap_count, so it is ok to use event->mmap_mutex to
5481 * serialize with perf_mmap here.
5483 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5484 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5486 * Stop all AUX events that are writing to this buffer,
5487 * so that we can free its AUX pages and corresponding PMU
5488 * data. Note that after rb::aux_mmap_count dropped to zero,
5489 * they won't start any more (see perf_aux_output_begin()).
5491 perf_pmu_output_stop(event);
5493 /* now it's safe to free the pages */
5494 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5495 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5497 /* this has to be the last one */
5499 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5501 mutex_unlock(&event->mmap_mutex);
5504 atomic_dec(&rb->mmap_count);
5506 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5509 ring_buffer_attach(event, NULL);
5510 mutex_unlock(&event->mmap_mutex);
5512 /* If there's still other mmap()s of this buffer, we're done. */
5513 if (atomic_read(&rb->mmap_count))
5517 * No other mmap()s, detach from all other events that might redirect
5518 * into the now unreachable buffer. Somewhat complicated by the
5519 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5523 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5524 if (!atomic_long_inc_not_zero(&event->refcount)) {
5526 * This event is en-route to free_event() which will
5527 * detach it and remove it from the list.
5533 mutex_lock(&event->mmap_mutex);
5535 * Check we didn't race with perf_event_set_output() which can
5536 * swizzle the rb from under us while we were waiting to
5537 * acquire mmap_mutex.
5539 * If we find a different rb; ignore this event, a next
5540 * iteration will no longer find it on the list. We have to
5541 * still restart the iteration to make sure we're not now
5542 * iterating the wrong list.
5544 if (event->rb == rb)
5545 ring_buffer_attach(event, NULL);
5547 mutex_unlock(&event->mmap_mutex);
5551 * Restart the iteration; either we're on the wrong list or
5552 * destroyed its integrity by doing a deletion.
5559 * It could be there's still a few 0-ref events on the list; they'll
5560 * get cleaned up by free_event() -- they'll also still have their
5561 * ref on the rb and will free it whenever they are done with it.
5563 * Aside from that, this buffer is 'fully' detached and unmapped,
5564 * undo the VM accounting.
5567 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5568 vma->vm_mm->pinned_vm -= mmap_locked;
5569 free_uid(mmap_user);
5572 ring_buffer_put(rb); /* could be last */
5575 static const struct vm_operations_struct perf_mmap_vmops = {
5576 .open = perf_mmap_open,
5577 .close = perf_mmap_close, /* non mergable */
5578 .fault = perf_mmap_fault,
5579 .page_mkwrite = perf_mmap_fault,
5582 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5584 struct perf_event *event = file->private_data;
5585 unsigned long user_locked, user_lock_limit;
5586 struct user_struct *user = current_user();
5587 unsigned long locked, lock_limit;
5588 struct ring_buffer *rb = NULL;
5589 unsigned long vma_size;
5590 unsigned long nr_pages;
5591 long user_extra = 0, extra = 0;
5592 int ret = 0, flags = 0;
5595 * Don't allow mmap() of inherited per-task counters. This would
5596 * create a performance issue due to all children writing to the
5599 if (event->cpu == -1 && event->attr.inherit)
5602 if (!(vma->vm_flags & VM_SHARED))
5605 vma_size = vma->vm_end - vma->vm_start;
5607 if (vma->vm_pgoff == 0) {
5608 nr_pages = (vma_size / PAGE_SIZE) - 1;
5611 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5612 * mapped, all subsequent mappings should have the same size
5613 * and offset. Must be above the normal perf buffer.
5615 u64 aux_offset, aux_size;
5620 nr_pages = vma_size / PAGE_SIZE;
5622 mutex_lock(&event->mmap_mutex);
5629 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5630 aux_size = READ_ONCE(rb->user_page->aux_size);
5632 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5635 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5638 /* already mapped with a different offset */
5639 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5642 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5645 /* already mapped with a different size */
5646 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5649 if (!is_power_of_2(nr_pages))
5652 if (!atomic_inc_not_zero(&rb->mmap_count))
5655 if (rb_has_aux(rb)) {
5656 atomic_inc(&rb->aux_mmap_count);
5661 atomic_set(&rb->aux_mmap_count, 1);
5662 user_extra = nr_pages;
5668 * If we have rb pages ensure they're a power-of-two number, so we
5669 * can do bitmasks instead of modulo.
5671 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5674 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5677 WARN_ON_ONCE(event->ctx->parent_ctx);
5679 mutex_lock(&event->mmap_mutex);
5681 if (event->rb->nr_pages != nr_pages) {
5686 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5688 * Raced against perf_mmap_close() through
5689 * perf_event_set_output(). Try again, hope for better
5692 mutex_unlock(&event->mmap_mutex);
5699 user_extra = nr_pages + 1;
5702 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5705 * Increase the limit linearly with more CPUs:
5707 user_lock_limit *= num_online_cpus();
5709 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5711 if (user_locked > user_lock_limit)
5712 extra = user_locked - user_lock_limit;
5714 lock_limit = rlimit(RLIMIT_MEMLOCK);
5715 lock_limit >>= PAGE_SHIFT;
5716 locked = vma->vm_mm->pinned_vm + extra;
5718 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5719 !capable(CAP_IPC_LOCK)) {
5724 WARN_ON(!rb && event->rb);
5726 if (vma->vm_flags & VM_WRITE)
5727 flags |= RING_BUFFER_WRITABLE;
5730 rb = rb_alloc(nr_pages,
5731 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5739 atomic_set(&rb->mmap_count, 1);
5740 rb->mmap_user = get_current_user();
5741 rb->mmap_locked = extra;
5743 ring_buffer_attach(event, rb);
5745 perf_event_init_userpage(event);
5746 perf_event_update_userpage(event);
5748 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5749 event->attr.aux_watermark, flags);
5751 rb->aux_mmap_locked = extra;
5756 atomic_long_add(user_extra, &user->locked_vm);
5757 vma->vm_mm->pinned_vm += extra;
5759 atomic_inc(&event->mmap_count);
5761 atomic_dec(&rb->mmap_count);
5764 mutex_unlock(&event->mmap_mutex);
5767 * Since pinned accounting is per vm we cannot allow fork() to copy our
5770 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5771 vma->vm_ops = &perf_mmap_vmops;
5773 if (event->pmu->event_mapped)
5774 event->pmu->event_mapped(event, vma->vm_mm);
5779 static int perf_fasync(int fd, struct file *filp, int on)
5781 struct inode *inode = file_inode(filp);
5782 struct perf_event *event = filp->private_data;
5786 retval = fasync_helper(fd, filp, on, &event->fasync);
5787 inode_unlock(inode);
5795 static const struct file_operations perf_fops = {
5796 .llseek = no_llseek,
5797 .release = perf_release,
5800 .unlocked_ioctl = perf_ioctl,
5801 .compat_ioctl = perf_compat_ioctl,
5803 .fasync = perf_fasync,
5809 * If there's data, ensure we set the poll() state and publish everything
5810 * to user-space before waking everybody up.
5813 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5815 /* only the parent has fasync state */
5817 event = event->parent;
5818 return &event->fasync;
5821 void perf_event_wakeup(struct perf_event *event)
5823 ring_buffer_wakeup(event);
5825 if (event->pending_kill) {
5826 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5827 event->pending_kill = 0;
5831 static void perf_pending_event_disable(struct perf_event *event)
5833 int cpu = READ_ONCE(event->pending_disable);
5838 if (cpu == smp_processor_id()) {
5839 WRITE_ONCE(event->pending_disable, -1);
5840 perf_event_disable_local(event);
5847 * perf_event_disable_inatomic()
5848 * @pending_disable = CPU-A;
5852 * @pending_disable = -1;
5855 * perf_event_disable_inatomic()
5856 * @pending_disable = CPU-B;
5857 * irq_work_queue(); // FAILS
5860 * perf_pending_event()
5862 * But the event runs on CPU-B and wants disabling there.
5864 irq_work_queue_on(&event->pending, cpu);
5867 static void perf_pending_event(struct irq_work *entry)
5869 struct perf_event *event = container_of(entry, struct perf_event, pending);
5872 rctx = perf_swevent_get_recursion_context();
5874 * If we 'fail' here, that's OK, it means recursion is already disabled
5875 * and we won't recurse 'further'.
5878 perf_pending_event_disable(event);
5880 if (event->pending_wakeup) {
5881 event->pending_wakeup = 0;
5882 perf_event_wakeup(event);
5886 perf_swevent_put_recursion_context(rctx);
5890 * We assume there is only KVM supporting the callbacks.
5891 * Later on, we might change it to a list if there is
5892 * another virtualization implementation supporting the callbacks.
5894 struct perf_guest_info_callbacks *perf_guest_cbs;
5896 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5898 perf_guest_cbs = cbs;
5901 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5903 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5905 perf_guest_cbs = NULL;
5908 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5911 perf_output_sample_regs(struct perf_output_handle *handle,
5912 struct pt_regs *regs, u64 mask)
5915 DECLARE_BITMAP(_mask, 64);
5917 bitmap_from_u64(_mask, mask);
5918 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5921 val = perf_reg_value(regs, bit);
5922 perf_output_put(handle, val);
5926 static void perf_sample_regs_user(struct perf_regs *regs_user,
5927 struct pt_regs *regs,
5928 struct pt_regs *regs_user_copy)
5930 if (user_mode(regs)) {
5931 regs_user->abi = perf_reg_abi(current);
5932 regs_user->regs = regs;
5933 } else if (!(current->flags & PF_KTHREAD)) {
5934 perf_get_regs_user(regs_user, regs, regs_user_copy);
5936 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5937 regs_user->regs = NULL;
5941 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5942 struct pt_regs *regs)
5944 regs_intr->regs = regs;
5945 regs_intr->abi = perf_reg_abi(current);
5950 * Get remaining task size from user stack pointer.
5952 * It'd be better to take stack vma map and limit this more
5953 * precisly, but there's no way to get it safely under interrupt,
5954 * so using TASK_SIZE as limit.
5956 static u64 perf_ustack_task_size(struct pt_regs *regs)
5958 unsigned long addr = perf_user_stack_pointer(regs);
5960 if (!addr || addr >= TASK_SIZE)
5963 return TASK_SIZE - addr;
5967 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5968 struct pt_regs *regs)
5972 /* No regs, no stack pointer, no dump. */
5977 * Check if we fit in with the requested stack size into the:
5979 * If we don't, we limit the size to the TASK_SIZE.
5981 * - remaining sample size
5982 * If we don't, we customize the stack size to
5983 * fit in to the remaining sample size.
5986 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5987 stack_size = min(stack_size, (u16) task_size);
5989 /* Current header size plus static size and dynamic size. */
5990 header_size += 2 * sizeof(u64);
5992 /* Do we fit in with the current stack dump size? */
5993 if ((u16) (header_size + stack_size) < header_size) {
5995 * If we overflow the maximum size for the sample,
5996 * we customize the stack dump size to fit in.
5998 stack_size = USHRT_MAX - header_size - sizeof(u64);
5999 stack_size = round_up(stack_size, sizeof(u64));
6006 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6007 struct pt_regs *regs)
6009 /* Case of a kernel thread, nothing to dump */
6012 perf_output_put(handle, size);
6022 * - the size requested by user or the best one we can fit
6023 * in to the sample max size
6025 * - user stack dump data
6027 * - the actual dumped size
6031 perf_output_put(handle, dump_size);
6034 sp = perf_user_stack_pointer(regs);
6037 rem = __output_copy_user(handle, (void *) sp, dump_size);
6039 dyn_size = dump_size - rem;
6041 perf_output_skip(handle, rem);
6044 perf_output_put(handle, dyn_size);
6048 static void __perf_event_header__init_id(struct perf_event_header *header,
6049 struct perf_sample_data *data,
6050 struct perf_event *event)
6052 u64 sample_type = event->attr.sample_type;
6054 data->type = sample_type;
6055 header->size += event->id_header_size;
6057 if (sample_type & PERF_SAMPLE_TID) {
6058 /* namespace issues */
6059 data->tid_entry.pid = perf_event_pid(event, current);
6060 data->tid_entry.tid = perf_event_tid(event, current);
6063 if (sample_type & PERF_SAMPLE_TIME)
6064 data->time = perf_event_clock(event);
6066 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6067 data->id = primary_event_id(event);
6069 if (sample_type & PERF_SAMPLE_STREAM_ID)
6070 data->stream_id = event->id;
6072 if (sample_type & PERF_SAMPLE_CPU) {
6073 data->cpu_entry.cpu = raw_smp_processor_id();
6074 data->cpu_entry.reserved = 0;
6078 void perf_event_header__init_id(struct perf_event_header *header,
6079 struct perf_sample_data *data,
6080 struct perf_event *event)
6082 if (event->attr.sample_id_all)
6083 __perf_event_header__init_id(header, data, event);
6086 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6087 struct perf_sample_data *data)
6089 u64 sample_type = data->type;
6091 if (sample_type & PERF_SAMPLE_TID)
6092 perf_output_put(handle, data->tid_entry);
6094 if (sample_type & PERF_SAMPLE_TIME)
6095 perf_output_put(handle, data->time);
6097 if (sample_type & PERF_SAMPLE_ID)
6098 perf_output_put(handle, data->id);
6100 if (sample_type & PERF_SAMPLE_STREAM_ID)
6101 perf_output_put(handle, data->stream_id);
6103 if (sample_type & PERF_SAMPLE_CPU)
6104 perf_output_put(handle, data->cpu_entry);
6106 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6107 perf_output_put(handle, data->id);
6110 void perf_event__output_id_sample(struct perf_event *event,
6111 struct perf_output_handle *handle,
6112 struct perf_sample_data *sample)
6114 if (event->attr.sample_id_all)
6115 __perf_event__output_id_sample(handle, sample);
6118 static void perf_output_read_one(struct perf_output_handle *handle,
6119 struct perf_event *event,
6120 u64 enabled, u64 running)
6122 u64 read_format = event->attr.read_format;
6126 values[n++] = perf_event_count(event);
6127 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6128 values[n++] = enabled +
6129 atomic64_read(&event->child_total_time_enabled);
6131 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6132 values[n++] = running +
6133 atomic64_read(&event->child_total_time_running);
6135 if (read_format & PERF_FORMAT_ID)
6136 values[n++] = primary_event_id(event);
6138 __output_copy(handle, values, n * sizeof(u64));
6141 static void perf_output_read_group(struct perf_output_handle *handle,
6142 struct perf_event *event,
6143 u64 enabled, u64 running)
6145 struct perf_event *leader = event->group_leader, *sub;
6146 u64 read_format = event->attr.read_format;
6150 values[n++] = 1 + leader->nr_siblings;
6152 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6153 values[n++] = enabled;
6155 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6156 values[n++] = running;
6158 if ((leader != event) &&
6159 (leader->state == PERF_EVENT_STATE_ACTIVE))
6160 leader->pmu->read(leader);
6162 values[n++] = perf_event_count(leader);
6163 if (read_format & PERF_FORMAT_ID)
6164 values[n++] = primary_event_id(leader);
6166 __output_copy(handle, values, n * sizeof(u64));
6168 for_each_sibling_event(sub, leader) {
6171 if ((sub != event) &&
6172 (sub->state == PERF_EVENT_STATE_ACTIVE))
6173 sub->pmu->read(sub);
6175 values[n++] = perf_event_count(sub);
6176 if (read_format & PERF_FORMAT_ID)
6177 values[n++] = primary_event_id(sub);
6179 __output_copy(handle, values, n * sizeof(u64));
6183 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6184 PERF_FORMAT_TOTAL_TIME_RUNNING)
6187 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6189 * The problem is that its both hard and excessively expensive to iterate the
6190 * child list, not to mention that its impossible to IPI the children running
6191 * on another CPU, from interrupt/NMI context.
6193 static void perf_output_read(struct perf_output_handle *handle,
6194 struct perf_event *event)
6196 u64 enabled = 0, running = 0, now;
6197 u64 read_format = event->attr.read_format;
6200 * compute total_time_enabled, total_time_running
6201 * based on snapshot values taken when the event
6202 * was last scheduled in.
6204 * we cannot simply called update_context_time()
6205 * because of locking issue as we are called in
6208 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6209 calc_timer_values(event, &now, &enabled, &running);
6211 if (event->attr.read_format & PERF_FORMAT_GROUP)
6212 perf_output_read_group(handle, event, enabled, running);
6214 perf_output_read_one(handle, event, enabled, running);
6217 void perf_output_sample(struct perf_output_handle *handle,
6218 struct perf_event_header *header,
6219 struct perf_sample_data *data,
6220 struct perf_event *event)
6222 u64 sample_type = data->type;
6224 perf_output_put(handle, *header);
6226 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6227 perf_output_put(handle, data->id);
6229 if (sample_type & PERF_SAMPLE_IP)
6230 perf_output_put(handle, data->ip);
6232 if (sample_type & PERF_SAMPLE_TID)
6233 perf_output_put(handle, data->tid_entry);
6235 if (sample_type & PERF_SAMPLE_TIME)
6236 perf_output_put(handle, data->time);
6238 if (sample_type & PERF_SAMPLE_ADDR)
6239 perf_output_put(handle, data->addr);
6241 if (sample_type & PERF_SAMPLE_ID)
6242 perf_output_put(handle, data->id);
6244 if (sample_type & PERF_SAMPLE_STREAM_ID)
6245 perf_output_put(handle, data->stream_id);
6247 if (sample_type & PERF_SAMPLE_CPU)
6248 perf_output_put(handle, data->cpu_entry);
6250 if (sample_type & PERF_SAMPLE_PERIOD)
6251 perf_output_put(handle, data->period);
6253 if (sample_type & PERF_SAMPLE_READ)
6254 perf_output_read(handle, event);
6256 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6259 size += data->callchain->nr;
6260 size *= sizeof(u64);
6261 __output_copy(handle, data->callchain, size);
6264 if (sample_type & PERF_SAMPLE_RAW) {
6265 struct perf_raw_record *raw = data->raw;
6268 struct perf_raw_frag *frag = &raw->frag;
6270 perf_output_put(handle, raw->size);
6273 __output_custom(handle, frag->copy,
6274 frag->data, frag->size);
6276 __output_copy(handle, frag->data,
6279 if (perf_raw_frag_last(frag))
6284 __output_skip(handle, NULL, frag->pad);
6290 .size = sizeof(u32),
6293 perf_output_put(handle, raw);
6297 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6298 if (data->br_stack) {
6301 size = data->br_stack->nr
6302 * sizeof(struct perf_branch_entry);
6304 perf_output_put(handle, data->br_stack->nr);
6305 perf_output_copy(handle, data->br_stack->entries, size);
6308 * we always store at least the value of nr
6311 perf_output_put(handle, nr);
6315 if (sample_type & PERF_SAMPLE_REGS_USER) {
6316 u64 abi = data->regs_user.abi;
6319 * If there are no regs to dump, notice it through
6320 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6322 perf_output_put(handle, abi);
6325 u64 mask = event->attr.sample_regs_user;
6326 perf_output_sample_regs(handle,
6327 data->regs_user.regs,
6332 if (sample_type & PERF_SAMPLE_STACK_USER) {
6333 perf_output_sample_ustack(handle,
6334 data->stack_user_size,
6335 data->regs_user.regs);
6338 if (sample_type & PERF_SAMPLE_WEIGHT)
6339 perf_output_put(handle, data->weight);
6341 if (sample_type & PERF_SAMPLE_DATA_SRC)
6342 perf_output_put(handle, data->data_src.val);
6344 if (sample_type & PERF_SAMPLE_TRANSACTION)
6345 perf_output_put(handle, data->txn);
6347 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6348 u64 abi = data->regs_intr.abi;
6350 * If there are no regs to dump, notice it through
6351 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6353 perf_output_put(handle, abi);
6356 u64 mask = event->attr.sample_regs_intr;
6358 perf_output_sample_regs(handle,
6359 data->regs_intr.regs,
6364 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6365 perf_output_put(handle, data->phys_addr);
6367 if (!event->attr.watermark) {
6368 int wakeup_events = event->attr.wakeup_events;
6370 if (wakeup_events) {
6371 struct ring_buffer *rb = handle->rb;
6372 int events = local_inc_return(&rb->events);
6374 if (events >= wakeup_events) {
6375 local_sub(wakeup_events, &rb->events);
6376 local_inc(&rb->wakeup);
6382 static u64 perf_virt_to_phys(u64 virt)
6385 struct page *p = NULL;
6390 if (virt >= TASK_SIZE) {
6391 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6392 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6393 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6394 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6397 * Walking the pages tables for user address.
6398 * Interrupts are disabled, so it prevents any tear down
6399 * of the page tables.
6400 * Try IRQ-safe __get_user_pages_fast first.
6401 * If failed, leave phys_addr as 0.
6403 if ((current->mm != NULL) &&
6404 (__get_user_pages_fast(virt, 1, 0, &p) == 1))
6405 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6414 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6416 struct perf_callchain_entry *
6417 perf_callchain(struct perf_event *event, struct pt_regs *regs)
6419 bool kernel = !event->attr.exclude_callchain_kernel;
6420 bool user = !event->attr.exclude_callchain_user;
6421 /* Disallow cross-task user callchains. */
6422 bool crosstask = event->ctx->task && event->ctx->task != current;
6423 const u32 max_stack = event->attr.sample_max_stack;
6424 struct perf_callchain_entry *callchain;
6426 if (!kernel && !user)
6427 return &__empty_callchain;
6429 callchain = get_perf_callchain(regs, 0, kernel, user,
6430 max_stack, crosstask, true);
6431 return callchain ?: &__empty_callchain;
6434 void perf_prepare_sample(struct perf_event_header *header,
6435 struct perf_sample_data *data,
6436 struct perf_event *event,
6437 struct pt_regs *regs)
6439 u64 sample_type = event->attr.sample_type;
6441 header->type = PERF_RECORD_SAMPLE;
6442 header->size = sizeof(*header) + event->header_size;
6445 header->misc |= perf_misc_flags(regs);
6447 __perf_event_header__init_id(header, data, event);
6449 if (sample_type & PERF_SAMPLE_IP)
6450 data->ip = perf_instruction_pointer(regs);
6452 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6455 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6456 data->callchain = perf_callchain(event, regs);
6458 size += data->callchain->nr;
6460 header->size += size * sizeof(u64);
6463 if (sample_type & PERF_SAMPLE_RAW) {
6464 struct perf_raw_record *raw = data->raw;
6468 struct perf_raw_frag *frag = &raw->frag;
6473 if (perf_raw_frag_last(frag))
6478 size = round_up(sum + sizeof(u32), sizeof(u64));
6479 raw->size = size - sizeof(u32);
6480 frag->pad = raw->size - sum;
6485 header->size += size;
6488 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6489 int size = sizeof(u64); /* nr */
6490 if (data->br_stack) {
6491 size += data->br_stack->nr
6492 * sizeof(struct perf_branch_entry);
6494 header->size += size;
6497 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6498 perf_sample_regs_user(&data->regs_user, regs,
6499 &data->regs_user_copy);
6501 if (sample_type & PERF_SAMPLE_REGS_USER) {
6502 /* regs dump ABI info */
6503 int size = sizeof(u64);
6505 if (data->regs_user.regs) {
6506 u64 mask = event->attr.sample_regs_user;
6507 size += hweight64(mask) * sizeof(u64);
6510 header->size += size;
6513 if (sample_type & PERF_SAMPLE_STACK_USER) {
6515 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6516 * processed as the last one or have additional check added
6517 * in case new sample type is added, because we could eat
6518 * up the rest of the sample size.
6520 u16 stack_size = event->attr.sample_stack_user;
6521 u16 size = sizeof(u64);
6523 stack_size = perf_sample_ustack_size(stack_size, header->size,
6524 data->regs_user.regs);
6527 * If there is something to dump, add space for the dump
6528 * itself and for the field that tells the dynamic size,
6529 * which is how many have been actually dumped.
6532 size += sizeof(u64) + stack_size;
6534 data->stack_user_size = stack_size;
6535 header->size += size;
6538 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6539 /* regs dump ABI info */
6540 int size = sizeof(u64);
6542 perf_sample_regs_intr(&data->regs_intr, regs);
6544 if (data->regs_intr.regs) {
6545 u64 mask = event->attr.sample_regs_intr;
6547 size += hweight64(mask) * sizeof(u64);
6550 header->size += size;
6553 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6554 data->phys_addr = perf_virt_to_phys(data->addr);
6557 static __always_inline void
6558 __perf_event_output(struct perf_event *event,
6559 struct perf_sample_data *data,
6560 struct pt_regs *regs,
6561 int (*output_begin)(struct perf_output_handle *,
6562 struct perf_event *,
6565 struct perf_output_handle handle;
6566 struct perf_event_header header;
6568 /* protect the callchain buffers */
6571 perf_prepare_sample(&header, data, event, regs);
6573 if (output_begin(&handle, event, header.size))
6576 perf_output_sample(&handle, &header, data, event);
6578 perf_output_end(&handle);
6585 perf_event_output_forward(struct perf_event *event,
6586 struct perf_sample_data *data,
6587 struct pt_regs *regs)
6589 __perf_event_output(event, data, regs, perf_output_begin_forward);
6593 perf_event_output_backward(struct perf_event *event,
6594 struct perf_sample_data *data,
6595 struct pt_regs *regs)
6597 __perf_event_output(event, data, regs, perf_output_begin_backward);
6601 perf_event_output(struct perf_event *event,
6602 struct perf_sample_data *data,
6603 struct pt_regs *regs)
6605 __perf_event_output(event, data, regs, perf_output_begin);
6612 struct perf_read_event {
6613 struct perf_event_header header;
6620 perf_event_read_event(struct perf_event *event,
6621 struct task_struct *task)
6623 struct perf_output_handle handle;
6624 struct perf_sample_data sample;
6625 struct perf_read_event read_event = {
6627 .type = PERF_RECORD_READ,
6629 .size = sizeof(read_event) + event->read_size,
6631 .pid = perf_event_pid(event, task),
6632 .tid = perf_event_tid(event, task),
6636 perf_event_header__init_id(&read_event.header, &sample, event);
6637 ret = perf_output_begin(&handle, event, read_event.header.size);
6641 perf_output_put(&handle, read_event);
6642 perf_output_read(&handle, event);
6643 perf_event__output_id_sample(event, &handle, &sample);
6645 perf_output_end(&handle);
6648 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6651 perf_iterate_ctx(struct perf_event_context *ctx,
6652 perf_iterate_f output,
6653 void *data, bool all)
6655 struct perf_event *event;
6657 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6659 if (event->state < PERF_EVENT_STATE_INACTIVE)
6661 if (!event_filter_match(event))
6665 output(event, data);
6669 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6671 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6672 struct perf_event *event;
6674 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6676 * Skip events that are not fully formed yet; ensure that
6677 * if we observe event->ctx, both event and ctx will be
6678 * complete enough. See perf_install_in_context().
6680 if (!smp_load_acquire(&event->ctx))
6683 if (event->state < PERF_EVENT_STATE_INACTIVE)
6685 if (!event_filter_match(event))
6687 output(event, data);
6692 * Iterate all events that need to receive side-band events.
6694 * For new callers; ensure that account_pmu_sb_event() includes
6695 * your event, otherwise it might not get delivered.
6698 perf_iterate_sb(perf_iterate_f output, void *data,
6699 struct perf_event_context *task_ctx)
6701 struct perf_event_context *ctx;
6708 * If we have task_ctx != NULL we only notify the task context itself.
6709 * The task_ctx is set only for EXIT events before releasing task
6713 perf_iterate_ctx(task_ctx, output, data, false);
6717 perf_iterate_sb_cpu(output, data);
6719 for_each_task_context_nr(ctxn) {
6720 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6722 perf_iterate_ctx(ctx, output, data, false);
6730 * Clear all file-based filters at exec, they'll have to be
6731 * re-instated when/if these objects are mmapped again.
6733 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6735 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6736 struct perf_addr_filter *filter;
6737 unsigned int restart = 0, count = 0;
6738 unsigned long flags;
6740 if (!has_addr_filter(event))
6743 raw_spin_lock_irqsave(&ifh->lock, flags);
6744 list_for_each_entry(filter, &ifh->list, entry) {
6745 if (filter->path.dentry) {
6746 event->addr_filters_offs[count] = 0;
6754 event->addr_filters_gen++;
6755 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6758 perf_event_stop(event, 1);
6761 void perf_event_exec(void)
6763 struct perf_event_context *ctx;
6767 for_each_task_context_nr(ctxn) {
6768 ctx = current->perf_event_ctxp[ctxn];
6772 perf_event_enable_on_exec(ctxn);
6774 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6780 struct remote_output {
6781 struct ring_buffer *rb;
6785 static void __perf_event_output_stop(struct perf_event *event, void *data)
6787 struct perf_event *parent = event->parent;
6788 struct remote_output *ro = data;
6789 struct ring_buffer *rb = ro->rb;
6790 struct stop_event_data sd = {
6794 if (!has_aux(event))
6801 * In case of inheritance, it will be the parent that links to the
6802 * ring-buffer, but it will be the child that's actually using it.
6804 * We are using event::rb to determine if the event should be stopped,
6805 * however this may race with ring_buffer_attach() (through set_output),
6806 * which will make us skip the event that actually needs to be stopped.
6807 * So ring_buffer_attach() has to stop an aux event before re-assigning
6810 if (rcu_dereference(parent->rb) == rb)
6811 ro->err = __perf_event_stop(&sd);
6814 static int __perf_pmu_output_stop(void *info)
6816 struct perf_event *event = info;
6817 struct pmu *pmu = event->ctx->pmu;
6818 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6819 struct remote_output ro = {
6824 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6825 if (cpuctx->task_ctx)
6826 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6833 static void perf_pmu_output_stop(struct perf_event *event)
6835 struct perf_event *iter;
6840 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6842 * For per-CPU events, we need to make sure that neither they
6843 * nor their children are running; for cpu==-1 events it's
6844 * sufficient to stop the event itself if it's active, since
6845 * it can't have children.
6849 cpu = READ_ONCE(iter->oncpu);
6854 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6855 if (err == -EAGAIN) {
6864 * task tracking -- fork/exit
6866 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6869 struct perf_task_event {
6870 struct task_struct *task;
6871 struct perf_event_context *task_ctx;
6874 struct perf_event_header header;
6884 static int perf_event_task_match(struct perf_event *event)
6886 return event->attr.comm || event->attr.mmap ||
6887 event->attr.mmap2 || event->attr.mmap_data ||
6891 static void perf_event_task_output(struct perf_event *event,
6894 struct perf_task_event *task_event = data;
6895 struct perf_output_handle handle;
6896 struct perf_sample_data sample;
6897 struct task_struct *task = task_event->task;
6898 int ret, size = task_event->event_id.header.size;
6900 if (!perf_event_task_match(event))
6903 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6905 ret = perf_output_begin(&handle, event,
6906 task_event->event_id.header.size);
6910 task_event->event_id.pid = perf_event_pid(event, task);
6911 task_event->event_id.ppid = perf_event_pid(event, current);
6913 task_event->event_id.tid = perf_event_tid(event, task);
6914 task_event->event_id.ptid = perf_event_tid(event, current);
6916 task_event->event_id.time = perf_event_clock(event);
6918 perf_output_put(&handle, task_event->event_id);
6920 perf_event__output_id_sample(event, &handle, &sample);
6922 perf_output_end(&handle);
6924 task_event->event_id.header.size = size;
6927 static void perf_event_task(struct task_struct *task,
6928 struct perf_event_context *task_ctx,
6931 struct perf_task_event task_event;
6933 if (!atomic_read(&nr_comm_events) &&
6934 !atomic_read(&nr_mmap_events) &&
6935 !atomic_read(&nr_task_events))
6938 task_event = (struct perf_task_event){
6940 .task_ctx = task_ctx,
6943 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6945 .size = sizeof(task_event.event_id),
6955 perf_iterate_sb(perf_event_task_output,
6960 void perf_event_fork(struct task_struct *task)
6962 perf_event_task(task, NULL, 1);
6963 perf_event_namespaces(task);
6970 struct perf_comm_event {
6971 struct task_struct *task;
6976 struct perf_event_header header;
6983 static int perf_event_comm_match(struct perf_event *event)
6985 return event->attr.comm;
6988 static void perf_event_comm_output(struct perf_event *event,
6991 struct perf_comm_event *comm_event = data;
6992 struct perf_output_handle handle;
6993 struct perf_sample_data sample;
6994 int size = comm_event->event_id.header.size;
6997 if (!perf_event_comm_match(event))
7000 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7001 ret = perf_output_begin(&handle, event,
7002 comm_event->event_id.header.size);
7007 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7008 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7010 perf_output_put(&handle, comm_event->event_id);
7011 __output_copy(&handle, comm_event->comm,
7012 comm_event->comm_size);
7014 perf_event__output_id_sample(event, &handle, &sample);
7016 perf_output_end(&handle);
7018 comm_event->event_id.header.size = size;
7021 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7023 char comm[TASK_COMM_LEN];
7026 memset(comm, 0, sizeof(comm));
7027 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7028 size = ALIGN(strlen(comm)+1, sizeof(u64));
7030 comm_event->comm = comm;
7031 comm_event->comm_size = size;
7033 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7035 perf_iterate_sb(perf_event_comm_output,
7040 void perf_event_comm(struct task_struct *task, bool exec)
7042 struct perf_comm_event comm_event;
7044 if (!atomic_read(&nr_comm_events))
7047 comm_event = (struct perf_comm_event){
7053 .type = PERF_RECORD_COMM,
7054 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7062 perf_event_comm_event(&comm_event);
7066 * namespaces tracking
7069 struct perf_namespaces_event {
7070 struct task_struct *task;
7073 struct perf_event_header header;
7078 struct perf_ns_link_info link_info[NR_NAMESPACES];
7082 static int perf_event_namespaces_match(struct perf_event *event)
7084 return event->attr.namespaces;
7087 static void perf_event_namespaces_output(struct perf_event *event,
7090 struct perf_namespaces_event *namespaces_event = data;
7091 struct perf_output_handle handle;
7092 struct perf_sample_data sample;
7093 u16 header_size = namespaces_event->event_id.header.size;
7096 if (!perf_event_namespaces_match(event))
7099 perf_event_header__init_id(&namespaces_event->event_id.header,
7101 ret = perf_output_begin(&handle, event,
7102 namespaces_event->event_id.header.size);
7106 namespaces_event->event_id.pid = perf_event_pid(event,
7107 namespaces_event->task);
7108 namespaces_event->event_id.tid = perf_event_tid(event,
7109 namespaces_event->task);
7111 perf_output_put(&handle, namespaces_event->event_id);
7113 perf_event__output_id_sample(event, &handle, &sample);
7115 perf_output_end(&handle);
7117 namespaces_event->event_id.header.size = header_size;
7120 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7121 struct task_struct *task,
7122 const struct proc_ns_operations *ns_ops)
7124 struct path ns_path;
7125 struct inode *ns_inode;
7128 error = ns_get_path(&ns_path, task, ns_ops);
7130 ns_inode = ns_path.dentry->d_inode;
7131 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7132 ns_link_info->ino = ns_inode->i_ino;
7137 void perf_event_namespaces(struct task_struct *task)
7139 struct perf_namespaces_event namespaces_event;
7140 struct perf_ns_link_info *ns_link_info;
7142 if (!atomic_read(&nr_namespaces_events))
7145 namespaces_event = (struct perf_namespaces_event){
7149 .type = PERF_RECORD_NAMESPACES,
7151 .size = sizeof(namespaces_event.event_id),
7155 .nr_namespaces = NR_NAMESPACES,
7156 /* .link_info[NR_NAMESPACES] */
7160 ns_link_info = namespaces_event.event_id.link_info;
7162 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7163 task, &mntns_operations);
7165 #ifdef CONFIG_USER_NS
7166 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7167 task, &userns_operations);
7169 #ifdef CONFIG_NET_NS
7170 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7171 task, &netns_operations);
7173 #ifdef CONFIG_UTS_NS
7174 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7175 task, &utsns_operations);
7177 #ifdef CONFIG_IPC_NS
7178 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7179 task, &ipcns_operations);
7181 #ifdef CONFIG_PID_NS
7182 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7183 task, &pidns_operations);
7185 #ifdef CONFIG_CGROUPS
7186 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7187 task, &cgroupns_operations);
7190 perf_iterate_sb(perf_event_namespaces_output,
7199 struct perf_mmap_event {
7200 struct vm_area_struct *vma;
7202 const char *file_name;
7210 struct perf_event_header header;
7220 static int perf_event_mmap_match(struct perf_event *event,
7223 struct perf_mmap_event *mmap_event = data;
7224 struct vm_area_struct *vma = mmap_event->vma;
7225 int executable = vma->vm_flags & VM_EXEC;
7227 return (!executable && event->attr.mmap_data) ||
7228 (executable && (event->attr.mmap || event->attr.mmap2));
7231 static void perf_event_mmap_output(struct perf_event *event,
7234 struct perf_mmap_event *mmap_event = data;
7235 struct perf_output_handle handle;
7236 struct perf_sample_data sample;
7237 int size = mmap_event->event_id.header.size;
7238 u32 type = mmap_event->event_id.header.type;
7241 if (!perf_event_mmap_match(event, data))
7244 if (event->attr.mmap2) {
7245 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7246 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7247 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7248 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7249 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7250 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7251 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7254 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7255 ret = perf_output_begin(&handle, event,
7256 mmap_event->event_id.header.size);
7260 mmap_event->event_id.pid = perf_event_pid(event, current);
7261 mmap_event->event_id.tid = perf_event_tid(event, current);
7263 perf_output_put(&handle, mmap_event->event_id);
7265 if (event->attr.mmap2) {
7266 perf_output_put(&handle, mmap_event->maj);
7267 perf_output_put(&handle, mmap_event->min);
7268 perf_output_put(&handle, mmap_event->ino);
7269 perf_output_put(&handle, mmap_event->ino_generation);
7270 perf_output_put(&handle, mmap_event->prot);
7271 perf_output_put(&handle, mmap_event->flags);
7274 __output_copy(&handle, mmap_event->file_name,
7275 mmap_event->file_size);
7277 perf_event__output_id_sample(event, &handle, &sample);
7279 perf_output_end(&handle);
7281 mmap_event->event_id.header.size = size;
7282 mmap_event->event_id.header.type = type;
7285 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7287 struct vm_area_struct *vma = mmap_event->vma;
7288 struct file *file = vma->vm_file;
7289 int maj = 0, min = 0;
7290 u64 ino = 0, gen = 0;
7291 u32 prot = 0, flags = 0;
7297 if (vma->vm_flags & VM_READ)
7299 if (vma->vm_flags & VM_WRITE)
7301 if (vma->vm_flags & VM_EXEC)
7304 if (vma->vm_flags & VM_MAYSHARE)
7307 flags = MAP_PRIVATE;
7309 if (vma->vm_flags & VM_DENYWRITE)
7310 flags |= MAP_DENYWRITE;
7311 if (vma->vm_flags & VM_MAYEXEC)
7312 flags |= MAP_EXECUTABLE;
7313 if (vma->vm_flags & VM_LOCKED)
7314 flags |= MAP_LOCKED;
7315 if (vma->vm_flags & VM_HUGETLB)
7316 flags |= MAP_HUGETLB;
7319 struct inode *inode;
7322 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7328 * d_path() works from the end of the rb backwards, so we
7329 * need to add enough zero bytes after the string to handle
7330 * the 64bit alignment we do later.
7332 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7337 inode = file_inode(vma->vm_file);
7338 dev = inode->i_sb->s_dev;
7340 gen = inode->i_generation;
7346 if (vma->vm_ops && vma->vm_ops->name) {
7347 name = (char *) vma->vm_ops->name(vma);
7352 name = (char *)arch_vma_name(vma);
7356 if (vma->vm_start <= vma->vm_mm->start_brk &&
7357 vma->vm_end >= vma->vm_mm->brk) {
7361 if (vma->vm_start <= vma->vm_mm->start_stack &&
7362 vma->vm_end >= vma->vm_mm->start_stack) {
7372 strlcpy(tmp, name, sizeof(tmp));
7376 * Since our buffer works in 8 byte units we need to align our string
7377 * size to a multiple of 8. However, we must guarantee the tail end is
7378 * zero'd out to avoid leaking random bits to userspace.
7380 size = strlen(name)+1;
7381 while (!IS_ALIGNED(size, sizeof(u64)))
7382 name[size++] = '\0';
7384 mmap_event->file_name = name;
7385 mmap_event->file_size = size;
7386 mmap_event->maj = maj;
7387 mmap_event->min = min;
7388 mmap_event->ino = ino;
7389 mmap_event->ino_generation = gen;
7390 mmap_event->prot = prot;
7391 mmap_event->flags = flags;
7393 if (!(vma->vm_flags & VM_EXEC))
7394 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7396 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7398 perf_iterate_sb(perf_event_mmap_output,
7406 * Check whether inode and address range match filter criteria.
7408 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7409 struct file *file, unsigned long offset,
7412 /* d_inode(NULL) won't be equal to any mapped user-space file */
7413 if (!filter->path.dentry)
7416 if (d_inode(filter->path.dentry) != file_inode(file))
7419 if (filter->offset > offset + size)
7422 if (filter->offset + filter->size < offset)
7428 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7430 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7431 struct vm_area_struct *vma = data;
7432 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
7433 struct file *file = vma->vm_file;
7434 struct perf_addr_filter *filter;
7435 unsigned int restart = 0, count = 0;
7437 if (!has_addr_filter(event))
7443 raw_spin_lock_irqsave(&ifh->lock, flags);
7444 list_for_each_entry(filter, &ifh->list, entry) {
7445 if (perf_addr_filter_match(filter, file, off,
7446 vma->vm_end - vma->vm_start)) {
7447 event->addr_filters_offs[count] = vma->vm_start;
7455 event->addr_filters_gen++;
7456 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7459 perf_event_stop(event, 1);
7463 * Adjust all task's events' filters to the new vma
7465 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7467 struct perf_event_context *ctx;
7471 * Data tracing isn't supported yet and as such there is no need
7472 * to keep track of anything that isn't related to executable code:
7474 if (!(vma->vm_flags & VM_EXEC))
7478 for_each_task_context_nr(ctxn) {
7479 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7483 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7488 void perf_event_mmap(struct vm_area_struct *vma)
7490 struct perf_mmap_event mmap_event;
7492 if (!atomic_read(&nr_mmap_events))
7495 mmap_event = (struct perf_mmap_event){
7501 .type = PERF_RECORD_MMAP,
7502 .misc = PERF_RECORD_MISC_USER,
7507 .start = vma->vm_start,
7508 .len = vma->vm_end - vma->vm_start,
7509 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7511 /* .maj (attr_mmap2 only) */
7512 /* .min (attr_mmap2 only) */
7513 /* .ino (attr_mmap2 only) */
7514 /* .ino_generation (attr_mmap2 only) */
7515 /* .prot (attr_mmap2 only) */
7516 /* .flags (attr_mmap2 only) */
7519 perf_addr_filters_adjust(vma);
7520 perf_event_mmap_event(&mmap_event);
7523 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7524 unsigned long size, u64 flags)
7526 struct perf_output_handle handle;
7527 struct perf_sample_data sample;
7528 struct perf_aux_event {
7529 struct perf_event_header header;
7535 .type = PERF_RECORD_AUX,
7537 .size = sizeof(rec),
7545 perf_event_header__init_id(&rec.header, &sample, event);
7546 ret = perf_output_begin(&handle, event, rec.header.size);
7551 perf_output_put(&handle, rec);
7552 perf_event__output_id_sample(event, &handle, &sample);
7554 perf_output_end(&handle);
7558 * Lost/dropped samples logging
7560 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7562 struct perf_output_handle handle;
7563 struct perf_sample_data sample;
7567 struct perf_event_header header;
7569 } lost_samples_event = {
7571 .type = PERF_RECORD_LOST_SAMPLES,
7573 .size = sizeof(lost_samples_event),
7578 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7580 ret = perf_output_begin(&handle, event,
7581 lost_samples_event.header.size);
7585 perf_output_put(&handle, lost_samples_event);
7586 perf_event__output_id_sample(event, &handle, &sample);
7587 perf_output_end(&handle);
7591 * context_switch tracking
7594 struct perf_switch_event {
7595 struct task_struct *task;
7596 struct task_struct *next_prev;
7599 struct perf_event_header header;
7605 static int perf_event_switch_match(struct perf_event *event)
7607 return event->attr.context_switch;
7610 static void perf_event_switch_output(struct perf_event *event, void *data)
7612 struct perf_switch_event *se = data;
7613 struct perf_output_handle handle;
7614 struct perf_sample_data sample;
7617 if (!perf_event_switch_match(event))
7620 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7621 if (event->ctx->task) {
7622 se->event_id.header.type = PERF_RECORD_SWITCH;
7623 se->event_id.header.size = sizeof(se->event_id.header);
7625 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7626 se->event_id.header.size = sizeof(se->event_id);
7627 se->event_id.next_prev_pid =
7628 perf_event_pid(event, se->next_prev);
7629 se->event_id.next_prev_tid =
7630 perf_event_tid(event, se->next_prev);
7633 perf_event_header__init_id(&se->event_id.header, &sample, event);
7635 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7639 if (event->ctx->task)
7640 perf_output_put(&handle, se->event_id.header);
7642 perf_output_put(&handle, se->event_id);
7644 perf_event__output_id_sample(event, &handle, &sample);
7646 perf_output_end(&handle);
7649 static void perf_event_switch(struct task_struct *task,
7650 struct task_struct *next_prev, bool sched_in)
7652 struct perf_switch_event switch_event;
7654 /* N.B. caller checks nr_switch_events != 0 */
7656 switch_event = (struct perf_switch_event){
7658 .next_prev = next_prev,
7662 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7665 /* .next_prev_pid */
7666 /* .next_prev_tid */
7670 if (!sched_in && task->state == TASK_RUNNING)
7671 switch_event.event_id.header.misc |=
7672 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
7674 perf_iterate_sb(perf_event_switch_output,
7680 * IRQ throttle logging
7683 static void perf_log_throttle(struct perf_event *event, int enable)
7685 struct perf_output_handle handle;
7686 struct perf_sample_data sample;
7690 struct perf_event_header header;
7694 } throttle_event = {
7696 .type = PERF_RECORD_THROTTLE,
7698 .size = sizeof(throttle_event),
7700 .time = perf_event_clock(event),
7701 .id = primary_event_id(event),
7702 .stream_id = event->id,
7706 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7708 perf_event_header__init_id(&throttle_event.header, &sample, event);
7710 ret = perf_output_begin(&handle, event,
7711 throttle_event.header.size);
7715 perf_output_put(&handle, throttle_event);
7716 perf_event__output_id_sample(event, &handle, &sample);
7717 perf_output_end(&handle);
7720 void perf_event_itrace_started(struct perf_event *event)
7722 event->attach_state |= PERF_ATTACH_ITRACE;
7725 static void perf_log_itrace_start(struct perf_event *event)
7727 struct perf_output_handle handle;
7728 struct perf_sample_data sample;
7729 struct perf_aux_event {
7730 struct perf_event_header header;
7737 event = event->parent;
7739 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7740 event->attach_state & PERF_ATTACH_ITRACE)
7743 rec.header.type = PERF_RECORD_ITRACE_START;
7744 rec.header.misc = 0;
7745 rec.header.size = sizeof(rec);
7746 rec.pid = perf_event_pid(event, current);
7747 rec.tid = perf_event_tid(event, current);
7749 perf_event_header__init_id(&rec.header, &sample, event);
7750 ret = perf_output_begin(&handle, event, rec.header.size);
7755 perf_output_put(&handle, rec);
7756 perf_event__output_id_sample(event, &handle, &sample);
7758 perf_output_end(&handle);
7762 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7764 struct hw_perf_event *hwc = &event->hw;
7768 seq = __this_cpu_read(perf_throttled_seq);
7769 if (seq != hwc->interrupts_seq) {
7770 hwc->interrupts_seq = seq;
7771 hwc->interrupts = 1;
7774 if (unlikely(throttle
7775 && hwc->interrupts >= max_samples_per_tick)) {
7776 __this_cpu_inc(perf_throttled_count);
7777 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7778 hwc->interrupts = MAX_INTERRUPTS;
7779 perf_log_throttle(event, 0);
7784 if (event->attr.freq) {
7785 u64 now = perf_clock();
7786 s64 delta = now - hwc->freq_time_stamp;
7788 hwc->freq_time_stamp = now;
7790 if (delta > 0 && delta < 2*TICK_NSEC)
7791 perf_adjust_period(event, delta, hwc->last_period, true);
7797 int perf_event_account_interrupt(struct perf_event *event)
7799 return __perf_event_account_interrupt(event, 1);
7803 * Generic event overflow handling, sampling.
7806 static int __perf_event_overflow(struct perf_event *event,
7807 int throttle, struct perf_sample_data *data,
7808 struct pt_regs *regs)
7810 int events = atomic_read(&event->event_limit);
7814 * Non-sampling counters might still use the PMI to fold short
7815 * hardware counters, ignore those.
7817 if (unlikely(!is_sampling_event(event)))
7820 ret = __perf_event_account_interrupt(event, throttle);
7823 * XXX event_limit might not quite work as expected on inherited
7827 event->pending_kill = POLL_IN;
7828 if (events && atomic_dec_and_test(&event->event_limit)) {
7830 event->pending_kill = POLL_HUP;
7832 perf_event_disable_inatomic(event);
7835 READ_ONCE(event->overflow_handler)(event, data, regs);
7837 if (*perf_event_fasync(event) && event->pending_kill) {
7838 event->pending_wakeup = 1;
7839 irq_work_queue(&event->pending);
7845 int perf_event_overflow(struct perf_event *event,
7846 struct perf_sample_data *data,
7847 struct pt_regs *regs)
7849 return __perf_event_overflow(event, 1, data, regs);
7853 * Generic software event infrastructure
7856 struct swevent_htable {
7857 struct swevent_hlist *swevent_hlist;
7858 struct mutex hlist_mutex;
7861 /* Recursion avoidance in each contexts */
7862 int recursion[PERF_NR_CONTEXTS];
7865 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7868 * We directly increment event->count and keep a second value in
7869 * event->hw.period_left to count intervals. This period event
7870 * is kept in the range [-sample_period, 0] so that we can use the
7874 u64 perf_swevent_set_period(struct perf_event *event)
7876 struct hw_perf_event *hwc = &event->hw;
7877 u64 period = hwc->last_period;
7881 hwc->last_period = hwc->sample_period;
7884 old = val = local64_read(&hwc->period_left);
7888 nr = div64_u64(period + val, period);
7889 offset = nr * period;
7891 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7897 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7898 struct perf_sample_data *data,
7899 struct pt_regs *regs)
7901 struct hw_perf_event *hwc = &event->hw;
7905 overflow = perf_swevent_set_period(event);
7907 if (hwc->interrupts == MAX_INTERRUPTS)
7910 for (; overflow; overflow--) {
7911 if (__perf_event_overflow(event, throttle,
7914 * We inhibit the overflow from happening when
7915 * hwc->interrupts == MAX_INTERRUPTS.
7923 static void perf_swevent_event(struct perf_event *event, u64 nr,
7924 struct perf_sample_data *data,
7925 struct pt_regs *regs)
7927 struct hw_perf_event *hwc = &event->hw;
7929 local64_add(nr, &event->count);
7934 if (!is_sampling_event(event))
7937 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7939 return perf_swevent_overflow(event, 1, data, regs);
7941 data->period = event->hw.last_period;
7943 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7944 return perf_swevent_overflow(event, 1, data, regs);
7946 if (local64_add_negative(nr, &hwc->period_left))
7949 perf_swevent_overflow(event, 0, data, regs);
7952 static int perf_exclude_event(struct perf_event *event,
7953 struct pt_regs *regs)
7955 if (event->hw.state & PERF_HES_STOPPED)
7959 if (event->attr.exclude_user && user_mode(regs))
7962 if (event->attr.exclude_kernel && !user_mode(regs))
7969 static int perf_swevent_match(struct perf_event *event,
7970 enum perf_type_id type,
7972 struct perf_sample_data *data,
7973 struct pt_regs *regs)
7975 if (event->attr.type != type)
7978 if (event->attr.config != event_id)
7981 if (perf_exclude_event(event, regs))
7987 static inline u64 swevent_hash(u64 type, u32 event_id)
7989 u64 val = event_id | (type << 32);
7991 return hash_64(val, SWEVENT_HLIST_BITS);
7994 static inline struct hlist_head *
7995 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7997 u64 hash = swevent_hash(type, event_id);
7999 return &hlist->heads[hash];
8002 /* For the read side: events when they trigger */
8003 static inline struct hlist_head *
8004 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
8006 struct swevent_hlist *hlist;
8008 hlist = rcu_dereference(swhash->swevent_hlist);
8012 return __find_swevent_head(hlist, type, event_id);
8015 /* For the event head insertion and removal in the hlist */
8016 static inline struct hlist_head *
8017 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
8019 struct swevent_hlist *hlist;
8020 u32 event_id = event->attr.config;
8021 u64 type = event->attr.type;
8024 * Event scheduling is always serialized against hlist allocation
8025 * and release. Which makes the protected version suitable here.
8026 * The context lock guarantees that.
8028 hlist = rcu_dereference_protected(swhash->swevent_hlist,
8029 lockdep_is_held(&event->ctx->lock));
8033 return __find_swevent_head(hlist, type, event_id);
8036 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
8038 struct perf_sample_data *data,
8039 struct pt_regs *regs)
8041 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8042 struct perf_event *event;
8043 struct hlist_head *head;
8046 head = find_swevent_head_rcu(swhash, type, event_id);
8050 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8051 if (perf_swevent_match(event, type, event_id, data, regs))
8052 perf_swevent_event(event, nr, data, regs);
8058 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8060 int perf_swevent_get_recursion_context(void)
8062 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8064 return get_recursion_context(swhash->recursion);
8066 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8068 void perf_swevent_put_recursion_context(int rctx)
8070 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8072 put_recursion_context(swhash->recursion, rctx);
8075 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8077 struct perf_sample_data data;
8079 if (WARN_ON_ONCE(!regs))
8082 perf_sample_data_init(&data, addr, 0);
8083 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8086 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8090 preempt_disable_notrace();
8091 rctx = perf_swevent_get_recursion_context();
8092 if (unlikely(rctx < 0))
8095 ___perf_sw_event(event_id, nr, regs, addr);
8097 perf_swevent_put_recursion_context(rctx);
8099 preempt_enable_notrace();
8102 static void perf_swevent_read(struct perf_event *event)
8106 static int perf_swevent_add(struct perf_event *event, int flags)
8108 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8109 struct hw_perf_event *hwc = &event->hw;
8110 struct hlist_head *head;
8112 if (is_sampling_event(event)) {
8113 hwc->last_period = hwc->sample_period;
8114 perf_swevent_set_period(event);
8117 hwc->state = !(flags & PERF_EF_START);
8119 head = find_swevent_head(swhash, event);
8120 if (WARN_ON_ONCE(!head))
8123 hlist_add_head_rcu(&event->hlist_entry, head);
8124 perf_event_update_userpage(event);
8129 static void perf_swevent_del(struct perf_event *event, int flags)
8131 hlist_del_rcu(&event->hlist_entry);
8134 static void perf_swevent_start(struct perf_event *event, int flags)
8136 event->hw.state = 0;
8139 static void perf_swevent_stop(struct perf_event *event, int flags)
8141 event->hw.state = PERF_HES_STOPPED;
8144 /* Deref the hlist from the update side */
8145 static inline struct swevent_hlist *
8146 swevent_hlist_deref(struct swevent_htable *swhash)
8148 return rcu_dereference_protected(swhash->swevent_hlist,
8149 lockdep_is_held(&swhash->hlist_mutex));
8152 static void swevent_hlist_release(struct swevent_htable *swhash)
8154 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
8159 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
8160 kfree_rcu(hlist, rcu_head);
8163 static void swevent_hlist_put_cpu(int cpu)
8165 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8167 mutex_lock(&swhash->hlist_mutex);
8169 if (!--swhash->hlist_refcount)
8170 swevent_hlist_release(swhash);
8172 mutex_unlock(&swhash->hlist_mutex);
8175 static void swevent_hlist_put(void)
8179 for_each_possible_cpu(cpu)
8180 swevent_hlist_put_cpu(cpu);
8183 static int swevent_hlist_get_cpu(int cpu)
8185 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8188 mutex_lock(&swhash->hlist_mutex);
8189 if (!swevent_hlist_deref(swhash) &&
8190 cpumask_test_cpu(cpu, perf_online_mask)) {
8191 struct swevent_hlist *hlist;
8193 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
8198 rcu_assign_pointer(swhash->swevent_hlist, hlist);
8200 swhash->hlist_refcount++;
8202 mutex_unlock(&swhash->hlist_mutex);
8207 static int swevent_hlist_get(void)
8209 int err, cpu, failed_cpu;
8211 mutex_lock(&pmus_lock);
8212 for_each_possible_cpu(cpu) {
8213 err = swevent_hlist_get_cpu(cpu);
8219 mutex_unlock(&pmus_lock);
8222 for_each_possible_cpu(cpu) {
8223 if (cpu == failed_cpu)
8225 swevent_hlist_put_cpu(cpu);
8227 mutex_unlock(&pmus_lock);
8231 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
8233 static void sw_perf_event_destroy(struct perf_event *event)
8235 u64 event_id = event->attr.config;
8237 WARN_ON(event->parent);
8239 static_key_slow_dec(&perf_swevent_enabled[event_id]);
8240 swevent_hlist_put();
8243 static int perf_swevent_init(struct perf_event *event)
8245 u64 event_id = event->attr.config;
8247 if (event->attr.type != PERF_TYPE_SOFTWARE)
8251 * no branch sampling for software events
8253 if (has_branch_stack(event))
8257 case PERF_COUNT_SW_CPU_CLOCK:
8258 case PERF_COUNT_SW_TASK_CLOCK:
8265 if (event_id >= PERF_COUNT_SW_MAX)
8268 if (!event->parent) {
8271 err = swevent_hlist_get();
8275 static_key_slow_inc(&perf_swevent_enabled[event_id]);
8276 event->destroy = sw_perf_event_destroy;
8282 static struct pmu perf_swevent = {
8283 .task_ctx_nr = perf_sw_context,
8285 .capabilities = PERF_PMU_CAP_NO_NMI,
8287 .event_init = perf_swevent_init,
8288 .add = perf_swevent_add,
8289 .del = perf_swevent_del,
8290 .start = perf_swevent_start,
8291 .stop = perf_swevent_stop,
8292 .read = perf_swevent_read,
8295 #ifdef CONFIG_EVENT_TRACING
8297 static int perf_tp_filter_match(struct perf_event *event,
8298 struct perf_sample_data *data)
8300 void *record = data->raw->frag.data;
8302 /* only top level events have filters set */
8304 event = event->parent;
8306 if (likely(!event->filter) || filter_match_preds(event->filter, record))
8311 static int perf_tp_event_match(struct perf_event *event,
8312 struct perf_sample_data *data,
8313 struct pt_regs *regs)
8315 if (event->hw.state & PERF_HES_STOPPED)
8318 * All tracepoints are from kernel-space.
8320 if (event->attr.exclude_kernel)
8323 if (!perf_tp_filter_match(event, data))
8329 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
8330 struct trace_event_call *call, u64 count,
8331 struct pt_regs *regs, struct hlist_head *head,
8332 struct task_struct *task)
8334 if (bpf_prog_array_valid(call)) {
8335 *(struct pt_regs **)raw_data = regs;
8336 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
8337 perf_swevent_put_recursion_context(rctx);
8341 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
8344 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
8346 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
8347 struct pt_regs *regs, struct hlist_head *head, int rctx,
8348 struct task_struct *task)
8350 struct perf_sample_data data;
8351 struct perf_event *event;
8353 struct perf_raw_record raw = {
8360 perf_sample_data_init(&data, 0, 0);
8363 perf_trace_buf_update(record, event_type);
8365 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8366 if (perf_tp_event_match(event, &data, regs))
8367 perf_swevent_event(event, count, &data, regs);
8371 * If we got specified a target task, also iterate its context and
8372 * deliver this event there too.
8374 if (task && task != current) {
8375 struct perf_event_context *ctx;
8376 struct trace_entry *entry = record;
8379 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8383 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8384 if (event->cpu != smp_processor_id())
8386 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8388 if (event->attr.config != entry->type)
8390 if (perf_tp_event_match(event, &data, regs))
8391 perf_swevent_event(event, count, &data, regs);
8397 perf_swevent_put_recursion_context(rctx);
8399 EXPORT_SYMBOL_GPL(perf_tp_event);
8401 static void tp_perf_event_destroy(struct perf_event *event)
8403 perf_trace_destroy(event);
8406 static int perf_tp_event_init(struct perf_event *event)
8410 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8414 * no branch sampling for tracepoint events
8416 if (has_branch_stack(event))
8419 err = perf_trace_init(event);
8423 event->destroy = tp_perf_event_destroy;
8428 static struct pmu perf_tracepoint = {
8429 .task_ctx_nr = perf_sw_context,
8431 .event_init = perf_tp_event_init,
8432 .add = perf_trace_add,
8433 .del = perf_trace_del,
8434 .start = perf_swevent_start,
8435 .stop = perf_swevent_stop,
8436 .read = perf_swevent_read,
8439 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
8441 * Flags in config, used by dynamic PMU kprobe and uprobe
8442 * The flags should match following PMU_FORMAT_ATTR().
8444 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
8445 * if not set, create kprobe/uprobe
8447 enum perf_probe_config {
8448 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
8451 PMU_FORMAT_ATTR(retprobe, "config:0");
8453 static struct attribute *probe_attrs[] = {
8454 &format_attr_retprobe.attr,
8458 static struct attribute_group probe_format_group = {
8460 .attrs = probe_attrs,
8463 static const struct attribute_group *probe_attr_groups[] = {
8464 &probe_format_group,
8469 #ifdef CONFIG_KPROBE_EVENTS
8470 static int perf_kprobe_event_init(struct perf_event *event);
8471 static struct pmu perf_kprobe = {
8472 .task_ctx_nr = perf_sw_context,
8473 .event_init = perf_kprobe_event_init,
8474 .add = perf_trace_add,
8475 .del = perf_trace_del,
8476 .start = perf_swevent_start,
8477 .stop = perf_swevent_stop,
8478 .read = perf_swevent_read,
8479 .attr_groups = probe_attr_groups,
8482 static int perf_kprobe_event_init(struct perf_event *event)
8487 if (event->attr.type != perf_kprobe.type)
8490 if (!capable(CAP_SYS_ADMIN))
8494 * no branch sampling for probe events
8496 if (has_branch_stack(event))
8499 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8500 err = perf_kprobe_init(event, is_retprobe);
8504 event->destroy = perf_kprobe_destroy;
8508 #endif /* CONFIG_KPROBE_EVENTS */
8510 #ifdef CONFIG_UPROBE_EVENTS
8511 static int perf_uprobe_event_init(struct perf_event *event);
8512 static struct pmu perf_uprobe = {
8513 .task_ctx_nr = perf_sw_context,
8514 .event_init = perf_uprobe_event_init,
8515 .add = perf_trace_add,
8516 .del = perf_trace_del,
8517 .start = perf_swevent_start,
8518 .stop = perf_swevent_stop,
8519 .read = perf_swevent_read,
8520 .attr_groups = probe_attr_groups,
8523 static int perf_uprobe_event_init(struct perf_event *event)
8528 if (event->attr.type != perf_uprobe.type)
8531 if (!capable(CAP_SYS_ADMIN))
8535 * no branch sampling for probe events
8537 if (has_branch_stack(event))
8540 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8541 err = perf_uprobe_init(event, is_retprobe);
8545 event->destroy = perf_uprobe_destroy;
8549 #endif /* CONFIG_UPROBE_EVENTS */
8551 static inline void perf_tp_register(void)
8553 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8554 #ifdef CONFIG_KPROBE_EVENTS
8555 perf_pmu_register(&perf_kprobe, "kprobe", -1);
8557 #ifdef CONFIG_UPROBE_EVENTS
8558 perf_pmu_register(&perf_uprobe, "uprobe", -1);
8562 static void perf_event_free_filter(struct perf_event *event)
8564 ftrace_profile_free_filter(event);
8567 #ifdef CONFIG_BPF_SYSCALL
8568 static void bpf_overflow_handler(struct perf_event *event,
8569 struct perf_sample_data *data,
8570 struct pt_regs *regs)
8572 struct bpf_perf_event_data_kern ctx = {
8578 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
8580 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8583 ret = BPF_PROG_RUN(event->prog, &ctx);
8586 __this_cpu_dec(bpf_prog_active);
8591 event->orig_overflow_handler(event, data, regs);
8594 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8596 struct bpf_prog *prog;
8598 if (event->overflow_handler_context)
8599 /* hw breakpoint or kernel counter */
8605 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8607 return PTR_ERR(prog);
8610 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8611 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8615 static void perf_event_free_bpf_handler(struct perf_event *event)
8617 struct bpf_prog *prog = event->prog;
8622 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8627 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8631 static void perf_event_free_bpf_handler(struct perf_event *event)
8637 * returns true if the event is a tracepoint, or a kprobe/upprobe created
8638 * with perf_event_open()
8640 static inline bool perf_event_is_tracing(struct perf_event *event)
8642 if (event->pmu == &perf_tracepoint)
8644 #ifdef CONFIG_KPROBE_EVENTS
8645 if (event->pmu == &perf_kprobe)
8648 #ifdef CONFIG_UPROBE_EVENTS
8649 if (event->pmu == &perf_uprobe)
8655 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8657 bool is_kprobe, is_tracepoint, is_syscall_tp;
8658 struct bpf_prog *prog;
8661 if (!perf_event_is_tracing(event))
8662 return perf_event_set_bpf_handler(event, prog_fd);
8664 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8665 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8666 is_syscall_tp = is_syscall_trace_event(event->tp_event);
8667 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
8668 /* bpf programs can only be attached to u/kprobe or tracepoint */
8671 prog = bpf_prog_get(prog_fd);
8673 return PTR_ERR(prog);
8675 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8676 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
8677 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8678 /* valid fd, but invalid bpf program type */
8683 /* Kprobe override only works for kprobes, not uprobes. */
8684 if (prog->kprobe_override &&
8685 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
8690 if (is_tracepoint || is_syscall_tp) {
8691 int off = trace_event_get_offsets(event->tp_event);
8693 if (prog->aux->max_ctx_offset > off) {
8699 ret = perf_event_attach_bpf_prog(event, prog);
8705 static void perf_event_free_bpf_prog(struct perf_event *event)
8707 if (!perf_event_is_tracing(event)) {
8708 perf_event_free_bpf_handler(event);
8711 perf_event_detach_bpf_prog(event);
8716 static inline void perf_tp_register(void)
8720 static void perf_event_free_filter(struct perf_event *event)
8724 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8729 static void perf_event_free_bpf_prog(struct perf_event *event)
8732 #endif /* CONFIG_EVENT_TRACING */
8734 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8735 void perf_bp_event(struct perf_event *bp, void *data)
8737 struct perf_sample_data sample;
8738 struct pt_regs *regs = data;
8740 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8742 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8743 perf_swevent_event(bp, 1, &sample, regs);
8748 * Allocate a new address filter
8750 static struct perf_addr_filter *
8751 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8753 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8754 struct perf_addr_filter *filter;
8756 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8760 INIT_LIST_HEAD(&filter->entry);
8761 list_add_tail(&filter->entry, filters);
8766 static void free_filters_list(struct list_head *filters)
8768 struct perf_addr_filter *filter, *iter;
8770 list_for_each_entry_safe(filter, iter, filters, entry) {
8771 path_put(&filter->path);
8772 list_del(&filter->entry);
8778 * Free existing address filters and optionally install new ones
8780 static void perf_addr_filters_splice(struct perf_event *event,
8781 struct list_head *head)
8783 unsigned long flags;
8786 if (!has_addr_filter(event))
8789 /* don't bother with children, they don't have their own filters */
8793 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8795 list_splice_init(&event->addr_filters.list, &list);
8797 list_splice(head, &event->addr_filters.list);
8799 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8801 free_filters_list(&list);
8805 * Scan through mm's vmas and see if one of them matches the
8806 * @filter; if so, adjust filter's address range.
8807 * Called with mm::mmap_sem down for reading.
8809 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
8810 struct mm_struct *mm)
8812 struct vm_area_struct *vma;
8814 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8815 struct file *file = vma->vm_file;
8816 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8817 unsigned long vma_size = vma->vm_end - vma->vm_start;
8822 if (!perf_addr_filter_match(filter, file, off, vma_size))
8825 return vma->vm_start;
8832 * Update event's address range filters based on the
8833 * task's existing mappings, if any.
8835 static void perf_event_addr_filters_apply(struct perf_event *event)
8837 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8838 struct task_struct *task = READ_ONCE(event->ctx->task);
8839 struct perf_addr_filter *filter;
8840 struct mm_struct *mm = NULL;
8841 unsigned int count = 0;
8842 unsigned long flags;
8845 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8846 * will stop on the parent's child_mutex that our caller is also holding
8848 if (task == TASK_TOMBSTONE)
8851 if (!ifh->nr_file_filters)
8854 mm = get_task_mm(event->ctx->task);
8858 down_read(&mm->mmap_sem);
8860 raw_spin_lock_irqsave(&ifh->lock, flags);
8861 list_for_each_entry(filter, &ifh->list, entry) {
8862 event->addr_filters_offs[count] = 0;
8865 * Adjust base offset if the filter is associated to a binary
8866 * that needs to be mapped:
8868 if (filter->path.dentry)
8869 event->addr_filters_offs[count] =
8870 perf_addr_filter_apply(filter, mm);
8875 event->addr_filters_gen++;
8876 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8878 up_read(&mm->mmap_sem);
8883 perf_event_stop(event, 1);
8887 * Address range filtering: limiting the data to certain
8888 * instruction address ranges. Filters are ioctl()ed to us from
8889 * userspace as ascii strings.
8891 * Filter string format:
8894 * where ACTION is one of the
8895 * * "filter": limit the trace to this region
8896 * * "start": start tracing from this address
8897 * * "stop": stop tracing at this address/region;
8899 * * for kernel addresses: <start address>[/<size>]
8900 * * for object files: <start address>[/<size>]@</path/to/object/file>
8902 * if <size> is not specified or is zero, the range is treated as a single
8903 * address; not valid for ACTION=="filter".
8917 IF_STATE_ACTION = 0,
8922 static const match_table_t if_tokens = {
8923 { IF_ACT_FILTER, "filter" },
8924 { IF_ACT_START, "start" },
8925 { IF_ACT_STOP, "stop" },
8926 { IF_SRC_FILE, "%u/%u@%s" },
8927 { IF_SRC_KERNEL, "%u/%u" },
8928 { IF_SRC_FILEADDR, "%u@%s" },
8929 { IF_SRC_KERNELADDR, "%u" },
8930 { IF_ACT_NONE, NULL },
8934 * Address filter string parser
8937 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8938 struct list_head *filters)
8940 struct perf_addr_filter *filter = NULL;
8941 char *start, *orig, *filename = NULL;
8942 substring_t args[MAX_OPT_ARGS];
8943 int state = IF_STATE_ACTION, token;
8944 unsigned int kernel = 0;
8947 orig = fstr = kstrdup(fstr, GFP_KERNEL);
8951 while ((start = strsep(&fstr, " ,\n")) != NULL) {
8952 static const enum perf_addr_filter_action_t actions[] = {
8953 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
8954 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
8955 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
8962 /* filter definition begins */
8963 if (state == IF_STATE_ACTION) {
8964 filter = perf_addr_filter_new(event, filters);
8969 token = match_token(start, if_tokens, args);
8974 if (state != IF_STATE_ACTION)
8977 filter->action = actions[token];
8978 state = IF_STATE_SOURCE;
8981 case IF_SRC_KERNELADDR:
8985 case IF_SRC_FILEADDR:
8987 if (state != IF_STATE_SOURCE)
8991 ret = kstrtoul(args[0].from, 0, &filter->offset);
8995 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
8997 ret = kstrtoul(args[1].from, 0, &filter->size);
9002 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
9003 int fpos = token == IF_SRC_FILE ? 2 : 1;
9005 filename = match_strdup(&args[fpos]);
9012 state = IF_STATE_END;
9020 * Filter definition is fully parsed, validate and install it.
9021 * Make sure that it doesn't contradict itself or the event's
9024 if (state == IF_STATE_END) {
9026 if (kernel && event->attr.exclude_kernel)
9030 * ACTION "filter" must have a non-zero length region
9033 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9042 * For now, we only support file-based filters
9043 * in per-task events; doing so for CPU-wide
9044 * events requires additional context switching
9045 * trickery, since same object code will be
9046 * mapped at different virtual addresses in
9047 * different processes.
9050 if (!event->ctx->task)
9051 goto fail_free_name;
9053 /* look up the path and grab its inode */
9054 ret = kern_path(filename, LOOKUP_FOLLOW,
9057 goto fail_free_name;
9063 if (!filter->path.dentry ||
9064 !S_ISREG(d_inode(filter->path.dentry)
9068 event->addr_filters.nr_file_filters++;
9071 /* ready to consume more filters */
9072 state = IF_STATE_ACTION;
9077 if (state != IF_STATE_ACTION)
9087 free_filters_list(filters);
9094 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
9100 * Since this is called in perf_ioctl() path, we're already holding
9103 lockdep_assert_held(&event->ctx->mutex);
9105 if (WARN_ON_ONCE(event->parent))
9108 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
9110 goto fail_clear_files;
9112 ret = event->pmu->addr_filters_validate(&filters);
9114 goto fail_free_filters;
9116 /* remove existing filters, if any */
9117 perf_addr_filters_splice(event, &filters);
9119 /* install new filters */
9120 perf_event_for_each_child(event, perf_event_addr_filters_apply);
9125 free_filters_list(&filters);
9128 event->addr_filters.nr_file_filters = 0;
9133 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
9138 filter_str = strndup_user(arg, PAGE_SIZE);
9139 if (IS_ERR(filter_str))
9140 return PTR_ERR(filter_str);
9142 #ifdef CONFIG_EVENT_TRACING
9143 if (perf_event_is_tracing(event)) {
9144 struct perf_event_context *ctx = event->ctx;
9147 * Beware, here be dragons!!
9149 * the tracepoint muck will deadlock against ctx->mutex, but
9150 * the tracepoint stuff does not actually need it. So
9151 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
9152 * already have a reference on ctx.
9154 * This can result in event getting moved to a different ctx,
9155 * but that does not affect the tracepoint state.
9157 mutex_unlock(&ctx->mutex);
9158 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
9159 mutex_lock(&ctx->mutex);
9162 if (has_addr_filter(event))
9163 ret = perf_event_set_addr_filter(event, filter_str);
9170 * hrtimer based swevent callback
9173 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
9175 enum hrtimer_restart ret = HRTIMER_RESTART;
9176 struct perf_sample_data data;
9177 struct pt_regs *regs;
9178 struct perf_event *event;
9181 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
9183 if (event->state != PERF_EVENT_STATE_ACTIVE)
9184 return HRTIMER_NORESTART;
9186 event->pmu->read(event);
9188 perf_sample_data_init(&data, 0, event->hw.last_period);
9189 regs = get_irq_regs();
9191 if (regs && !perf_exclude_event(event, regs)) {
9192 if (!(event->attr.exclude_idle && is_idle_task(current)))
9193 if (__perf_event_overflow(event, 1, &data, regs))
9194 ret = HRTIMER_NORESTART;
9197 period = max_t(u64, 10000, event->hw.sample_period);
9198 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
9203 static void perf_swevent_start_hrtimer(struct perf_event *event)
9205 struct hw_perf_event *hwc = &event->hw;
9208 if (!is_sampling_event(event))
9211 period = local64_read(&hwc->period_left);
9216 local64_set(&hwc->period_left, 0);
9218 period = max_t(u64, 10000, hwc->sample_period);
9220 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
9221 HRTIMER_MODE_REL_PINNED);
9224 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
9226 struct hw_perf_event *hwc = &event->hw;
9228 if (is_sampling_event(event)) {
9229 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
9230 local64_set(&hwc->period_left, ktime_to_ns(remaining));
9232 hrtimer_cancel(&hwc->hrtimer);
9236 static void perf_swevent_init_hrtimer(struct perf_event *event)
9238 struct hw_perf_event *hwc = &event->hw;
9240 if (!is_sampling_event(event))
9243 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
9244 hwc->hrtimer.function = perf_swevent_hrtimer;
9247 * Since hrtimers have a fixed rate, we can do a static freq->period
9248 * mapping and avoid the whole period adjust feedback stuff.
9250 if (event->attr.freq) {
9251 long freq = event->attr.sample_freq;
9253 event->attr.sample_period = NSEC_PER_SEC / freq;
9254 hwc->sample_period = event->attr.sample_period;
9255 local64_set(&hwc->period_left, hwc->sample_period);
9256 hwc->last_period = hwc->sample_period;
9257 event->attr.freq = 0;
9262 * Software event: cpu wall time clock
9265 static void cpu_clock_event_update(struct perf_event *event)
9270 now = local_clock();
9271 prev = local64_xchg(&event->hw.prev_count, now);
9272 local64_add(now - prev, &event->count);
9275 static void cpu_clock_event_start(struct perf_event *event, int flags)
9277 local64_set(&event->hw.prev_count, local_clock());
9278 perf_swevent_start_hrtimer(event);
9281 static void cpu_clock_event_stop(struct perf_event *event, int flags)
9283 perf_swevent_cancel_hrtimer(event);
9284 cpu_clock_event_update(event);
9287 static int cpu_clock_event_add(struct perf_event *event, int flags)
9289 if (flags & PERF_EF_START)
9290 cpu_clock_event_start(event, flags);
9291 perf_event_update_userpage(event);
9296 static void cpu_clock_event_del(struct perf_event *event, int flags)
9298 cpu_clock_event_stop(event, flags);
9301 static void cpu_clock_event_read(struct perf_event *event)
9303 cpu_clock_event_update(event);
9306 static int cpu_clock_event_init(struct perf_event *event)
9308 if (event->attr.type != PERF_TYPE_SOFTWARE)
9311 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
9315 * no branch sampling for software events
9317 if (has_branch_stack(event))
9320 perf_swevent_init_hrtimer(event);
9325 static struct pmu perf_cpu_clock = {
9326 .task_ctx_nr = perf_sw_context,
9328 .capabilities = PERF_PMU_CAP_NO_NMI,
9330 .event_init = cpu_clock_event_init,
9331 .add = cpu_clock_event_add,
9332 .del = cpu_clock_event_del,
9333 .start = cpu_clock_event_start,
9334 .stop = cpu_clock_event_stop,
9335 .read = cpu_clock_event_read,
9339 * Software event: task time clock
9342 static void task_clock_event_update(struct perf_event *event, u64 now)
9347 prev = local64_xchg(&event->hw.prev_count, now);
9349 local64_add(delta, &event->count);
9352 static void task_clock_event_start(struct perf_event *event, int flags)
9354 local64_set(&event->hw.prev_count, event->ctx->time);
9355 perf_swevent_start_hrtimer(event);
9358 static void task_clock_event_stop(struct perf_event *event, int flags)
9360 perf_swevent_cancel_hrtimer(event);
9361 task_clock_event_update(event, event->ctx->time);
9364 static int task_clock_event_add(struct perf_event *event, int flags)
9366 if (flags & PERF_EF_START)
9367 task_clock_event_start(event, flags);
9368 perf_event_update_userpage(event);
9373 static void task_clock_event_del(struct perf_event *event, int flags)
9375 task_clock_event_stop(event, PERF_EF_UPDATE);
9378 static void task_clock_event_read(struct perf_event *event)
9380 u64 now = perf_clock();
9381 u64 delta = now - event->ctx->timestamp;
9382 u64 time = event->ctx->time + delta;
9384 task_clock_event_update(event, time);
9387 static int task_clock_event_init(struct perf_event *event)
9389 if (event->attr.type != PERF_TYPE_SOFTWARE)
9392 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
9396 * no branch sampling for software events
9398 if (has_branch_stack(event))
9401 perf_swevent_init_hrtimer(event);
9406 static struct pmu perf_task_clock = {
9407 .task_ctx_nr = perf_sw_context,
9409 .capabilities = PERF_PMU_CAP_NO_NMI,
9411 .event_init = task_clock_event_init,
9412 .add = task_clock_event_add,
9413 .del = task_clock_event_del,
9414 .start = task_clock_event_start,
9415 .stop = task_clock_event_stop,
9416 .read = task_clock_event_read,
9419 static void perf_pmu_nop_void(struct pmu *pmu)
9423 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
9427 static int perf_pmu_nop_int(struct pmu *pmu)
9432 static int perf_event_nop_int(struct perf_event *event, u64 value)
9437 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
9439 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
9441 __this_cpu_write(nop_txn_flags, flags);
9443 if (flags & ~PERF_PMU_TXN_ADD)
9446 perf_pmu_disable(pmu);
9449 static int perf_pmu_commit_txn(struct pmu *pmu)
9451 unsigned int flags = __this_cpu_read(nop_txn_flags);
9453 __this_cpu_write(nop_txn_flags, 0);
9455 if (flags & ~PERF_PMU_TXN_ADD)
9458 perf_pmu_enable(pmu);
9462 static void perf_pmu_cancel_txn(struct pmu *pmu)
9464 unsigned int flags = __this_cpu_read(nop_txn_flags);
9466 __this_cpu_write(nop_txn_flags, 0);
9468 if (flags & ~PERF_PMU_TXN_ADD)
9471 perf_pmu_enable(pmu);
9474 static int perf_event_idx_default(struct perf_event *event)
9480 * Ensures all contexts with the same task_ctx_nr have the same
9481 * pmu_cpu_context too.
9483 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
9490 list_for_each_entry(pmu, &pmus, entry) {
9491 if (pmu->task_ctx_nr == ctxn)
9492 return pmu->pmu_cpu_context;
9498 static void free_pmu_context(struct pmu *pmu)
9501 * Static contexts such as perf_sw_context have a global lifetime
9502 * and may be shared between different PMUs. Avoid freeing them
9503 * when a single PMU is going away.
9505 if (pmu->task_ctx_nr > perf_invalid_context)
9508 free_percpu(pmu->pmu_cpu_context);
9512 * Let userspace know that this PMU supports address range filtering:
9514 static ssize_t nr_addr_filters_show(struct device *dev,
9515 struct device_attribute *attr,
9518 struct pmu *pmu = dev_get_drvdata(dev);
9520 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
9522 DEVICE_ATTR_RO(nr_addr_filters);
9524 static struct idr pmu_idr;
9527 type_show(struct device *dev, struct device_attribute *attr, char *page)
9529 struct pmu *pmu = dev_get_drvdata(dev);
9531 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
9533 static DEVICE_ATTR_RO(type);
9536 perf_event_mux_interval_ms_show(struct device *dev,
9537 struct device_attribute *attr,
9540 struct pmu *pmu = dev_get_drvdata(dev);
9542 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
9545 static DEFINE_MUTEX(mux_interval_mutex);
9548 perf_event_mux_interval_ms_store(struct device *dev,
9549 struct device_attribute *attr,
9550 const char *buf, size_t count)
9552 struct pmu *pmu = dev_get_drvdata(dev);
9553 int timer, cpu, ret;
9555 ret = kstrtoint(buf, 0, &timer);
9562 /* same value, noting to do */
9563 if (timer == pmu->hrtimer_interval_ms)
9566 mutex_lock(&mux_interval_mutex);
9567 pmu->hrtimer_interval_ms = timer;
9569 /* update all cpuctx for this PMU */
9571 for_each_online_cpu(cpu) {
9572 struct perf_cpu_context *cpuctx;
9573 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9574 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9576 cpu_function_call(cpu,
9577 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
9580 mutex_unlock(&mux_interval_mutex);
9584 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9586 static struct attribute *pmu_dev_attrs[] = {
9587 &dev_attr_type.attr,
9588 &dev_attr_perf_event_mux_interval_ms.attr,
9591 ATTRIBUTE_GROUPS(pmu_dev);
9593 static int pmu_bus_running;
9594 static struct bus_type pmu_bus = {
9595 .name = "event_source",
9596 .dev_groups = pmu_dev_groups,
9599 static void pmu_dev_release(struct device *dev)
9604 static int pmu_dev_alloc(struct pmu *pmu)
9608 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9612 pmu->dev->groups = pmu->attr_groups;
9613 device_initialize(pmu->dev);
9614 ret = dev_set_name(pmu->dev, "%s", pmu->name);
9618 dev_set_drvdata(pmu->dev, pmu);
9619 pmu->dev->bus = &pmu_bus;
9620 pmu->dev->release = pmu_dev_release;
9621 ret = device_add(pmu->dev);
9625 /* For PMUs with address filters, throw in an extra attribute: */
9626 if (pmu->nr_addr_filters)
9627 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9636 device_del(pmu->dev);
9639 put_device(pmu->dev);
9643 static struct lock_class_key cpuctx_mutex;
9644 static struct lock_class_key cpuctx_lock;
9646 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9650 mutex_lock(&pmus_lock);
9652 pmu->pmu_disable_count = alloc_percpu(int);
9653 if (!pmu->pmu_disable_count)
9662 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9670 if (pmu_bus_running) {
9671 ret = pmu_dev_alloc(pmu);
9677 if (pmu->task_ctx_nr == perf_hw_context) {
9678 static int hw_context_taken = 0;
9681 * Other than systems with heterogeneous CPUs, it never makes
9682 * sense for two PMUs to share perf_hw_context. PMUs which are
9683 * uncore must use perf_invalid_context.
9685 if (WARN_ON_ONCE(hw_context_taken &&
9686 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9687 pmu->task_ctx_nr = perf_invalid_context;
9689 hw_context_taken = 1;
9692 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9693 if (pmu->pmu_cpu_context)
9694 goto got_cpu_context;
9697 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9698 if (!pmu->pmu_cpu_context)
9701 for_each_possible_cpu(cpu) {
9702 struct perf_cpu_context *cpuctx;
9704 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9705 __perf_event_init_context(&cpuctx->ctx);
9706 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9707 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9708 cpuctx->ctx.pmu = pmu;
9709 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9711 __perf_mux_hrtimer_init(cpuctx, cpu);
9715 if (!pmu->start_txn) {
9716 if (pmu->pmu_enable) {
9718 * If we have pmu_enable/pmu_disable calls, install
9719 * transaction stubs that use that to try and batch
9720 * hardware accesses.
9722 pmu->start_txn = perf_pmu_start_txn;
9723 pmu->commit_txn = perf_pmu_commit_txn;
9724 pmu->cancel_txn = perf_pmu_cancel_txn;
9726 pmu->start_txn = perf_pmu_nop_txn;
9727 pmu->commit_txn = perf_pmu_nop_int;
9728 pmu->cancel_txn = perf_pmu_nop_void;
9732 if (!pmu->pmu_enable) {
9733 pmu->pmu_enable = perf_pmu_nop_void;
9734 pmu->pmu_disable = perf_pmu_nop_void;
9737 if (!pmu->check_period)
9738 pmu->check_period = perf_event_nop_int;
9740 if (!pmu->event_idx)
9741 pmu->event_idx = perf_event_idx_default;
9743 list_add_rcu(&pmu->entry, &pmus);
9744 atomic_set(&pmu->exclusive_cnt, 0);
9747 mutex_unlock(&pmus_lock);
9752 device_del(pmu->dev);
9753 put_device(pmu->dev);
9756 if (pmu->type >= PERF_TYPE_MAX)
9757 idr_remove(&pmu_idr, pmu->type);
9760 free_percpu(pmu->pmu_disable_count);
9763 EXPORT_SYMBOL_GPL(perf_pmu_register);
9765 void perf_pmu_unregister(struct pmu *pmu)
9767 mutex_lock(&pmus_lock);
9768 list_del_rcu(&pmu->entry);
9771 * We dereference the pmu list under both SRCU and regular RCU, so
9772 * synchronize against both of those.
9774 synchronize_srcu(&pmus_srcu);
9777 free_percpu(pmu->pmu_disable_count);
9778 if (pmu->type >= PERF_TYPE_MAX)
9779 idr_remove(&pmu_idr, pmu->type);
9780 if (pmu_bus_running) {
9781 if (pmu->nr_addr_filters)
9782 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9783 device_del(pmu->dev);
9784 put_device(pmu->dev);
9786 free_pmu_context(pmu);
9787 mutex_unlock(&pmus_lock);
9789 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9791 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9793 struct perf_event_context *ctx = NULL;
9796 if (!try_module_get(pmu->module))
9800 * A number of pmu->event_init() methods iterate the sibling_list to,
9801 * for example, validate if the group fits on the PMU. Therefore,
9802 * if this is a sibling event, acquire the ctx->mutex to protect
9805 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
9807 * This ctx->mutex can nest when we're called through
9808 * inheritance. See the perf_event_ctx_lock_nested() comment.
9810 ctx = perf_event_ctx_lock_nested(event->group_leader,
9811 SINGLE_DEPTH_NESTING);
9816 ret = pmu->event_init(event);
9819 perf_event_ctx_unlock(event->group_leader, ctx);
9822 module_put(pmu->module);
9827 static struct pmu *perf_init_event(struct perf_event *event)
9833 idx = srcu_read_lock(&pmus_srcu);
9835 /* Try parent's PMU first: */
9836 if (event->parent && event->parent->pmu) {
9837 pmu = event->parent->pmu;
9838 ret = perf_try_init_event(pmu, event);
9844 pmu = idr_find(&pmu_idr, event->attr.type);
9847 ret = perf_try_init_event(pmu, event);
9853 list_for_each_entry_rcu(pmu, &pmus, entry) {
9854 ret = perf_try_init_event(pmu, event);
9858 if (ret != -ENOENT) {
9863 pmu = ERR_PTR(-ENOENT);
9865 srcu_read_unlock(&pmus_srcu, idx);
9870 static void attach_sb_event(struct perf_event *event)
9872 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9874 raw_spin_lock(&pel->lock);
9875 list_add_rcu(&event->sb_list, &pel->list);
9876 raw_spin_unlock(&pel->lock);
9880 * We keep a list of all !task (and therefore per-cpu) events
9881 * that need to receive side-band records.
9883 * This avoids having to scan all the various PMU per-cpu contexts
9886 static void account_pmu_sb_event(struct perf_event *event)
9888 if (is_sb_event(event))
9889 attach_sb_event(event);
9892 static void account_event_cpu(struct perf_event *event, int cpu)
9897 if (is_cgroup_event(event))
9898 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9901 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9902 static void account_freq_event_nohz(void)
9904 #ifdef CONFIG_NO_HZ_FULL
9905 /* Lock so we don't race with concurrent unaccount */
9906 spin_lock(&nr_freq_lock);
9907 if (atomic_inc_return(&nr_freq_events) == 1)
9908 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9909 spin_unlock(&nr_freq_lock);
9913 static void account_freq_event(void)
9915 if (tick_nohz_full_enabled())
9916 account_freq_event_nohz();
9918 atomic_inc(&nr_freq_events);
9922 static void account_event(struct perf_event *event)
9929 if (event->attach_state & PERF_ATTACH_TASK)
9931 if (event->attr.mmap || event->attr.mmap_data)
9932 atomic_inc(&nr_mmap_events);
9933 if (event->attr.comm)
9934 atomic_inc(&nr_comm_events);
9935 if (event->attr.namespaces)
9936 atomic_inc(&nr_namespaces_events);
9937 if (event->attr.task)
9938 atomic_inc(&nr_task_events);
9939 if (event->attr.freq)
9940 account_freq_event();
9941 if (event->attr.context_switch) {
9942 atomic_inc(&nr_switch_events);
9945 if (has_branch_stack(event))
9947 if (is_cgroup_event(event))
9952 * We need the mutex here because static_branch_enable()
9953 * must complete *before* the perf_sched_count increment
9956 if (atomic_inc_not_zero(&perf_sched_count))
9959 mutex_lock(&perf_sched_mutex);
9960 if (!atomic_read(&perf_sched_count)) {
9961 static_branch_enable(&perf_sched_events);
9963 * Guarantee that all CPUs observe they key change and
9964 * call the perf scheduling hooks before proceeding to
9965 * install events that need them.
9967 synchronize_sched();
9970 * Now that we have waited for the sync_sched(), allow further
9971 * increments to by-pass the mutex.
9973 atomic_inc(&perf_sched_count);
9974 mutex_unlock(&perf_sched_mutex);
9978 account_event_cpu(event, event->cpu);
9980 account_pmu_sb_event(event);
9984 * Allocate and initialize an event structure
9986 static struct perf_event *
9987 perf_event_alloc(struct perf_event_attr *attr, int cpu,
9988 struct task_struct *task,
9989 struct perf_event *group_leader,
9990 struct perf_event *parent_event,
9991 perf_overflow_handler_t overflow_handler,
9992 void *context, int cgroup_fd)
9995 struct perf_event *event;
9996 struct hw_perf_event *hwc;
9999 if ((unsigned)cpu >= nr_cpu_ids) {
10000 if (!task || cpu != -1)
10001 return ERR_PTR(-EINVAL);
10004 event = kzalloc(sizeof(*event), GFP_KERNEL);
10006 return ERR_PTR(-ENOMEM);
10009 * Single events are their own group leaders, with an
10010 * empty sibling list:
10013 group_leader = event;
10015 mutex_init(&event->child_mutex);
10016 INIT_LIST_HEAD(&event->child_list);
10018 INIT_LIST_HEAD(&event->event_entry);
10019 INIT_LIST_HEAD(&event->sibling_list);
10020 INIT_LIST_HEAD(&event->active_list);
10021 init_event_group(event);
10022 INIT_LIST_HEAD(&event->rb_entry);
10023 INIT_LIST_HEAD(&event->active_entry);
10024 INIT_LIST_HEAD(&event->addr_filters.list);
10025 INIT_HLIST_NODE(&event->hlist_entry);
10028 init_waitqueue_head(&event->waitq);
10029 event->pending_disable = -1;
10030 init_irq_work(&event->pending, perf_pending_event);
10032 mutex_init(&event->mmap_mutex);
10033 raw_spin_lock_init(&event->addr_filters.lock);
10035 atomic_long_set(&event->refcount, 1);
10037 event->attr = *attr;
10038 event->group_leader = group_leader;
10042 event->parent = parent_event;
10044 event->ns = get_pid_ns(task_active_pid_ns(current));
10045 event->id = atomic64_inc_return(&perf_event_id);
10047 event->state = PERF_EVENT_STATE_INACTIVE;
10050 event->attach_state = PERF_ATTACH_TASK;
10052 * XXX pmu::event_init needs to know what task to account to
10053 * and we cannot use the ctx information because we need the
10054 * pmu before we get a ctx.
10056 get_task_struct(task);
10057 event->hw.target = task;
10060 event->clock = &local_clock;
10062 event->clock = parent_event->clock;
10064 if (!overflow_handler && parent_event) {
10065 overflow_handler = parent_event->overflow_handler;
10066 context = parent_event->overflow_handler_context;
10067 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
10068 if (overflow_handler == bpf_overflow_handler) {
10069 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
10071 if (IS_ERR(prog)) {
10072 err = PTR_ERR(prog);
10075 event->prog = prog;
10076 event->orig_overflow_handler =
10077 parent_event->orig_overflow_handler;
10082 if (overflow_handler) {
10083 event->overflow_handler = overflow_handler;
10084 event->overflow_handler_context = context;
10085 } else if (is_write_backward(event)){
10086 event->overflow_handler = perf_event_output_backward;
10087 event->overflow_handler_context = NULL;
10089 event->overflow_handler = perf_event_output_forward;
10090 event->overflow_handler_context = NULL;
10093 perf_event__state_init(event);
10098 hwc->sample_period = attr->sample_period;
10099 if (attr->freq && attr->sample_freq)
10100 hwc->sample_period = 1;
10101 hwc->last_period = hwc->sample_period;
10103 local64_set(&hwc->period_left, hwc->sample_period);
10106 * We currently do not support PERF_SAMPLE_READ on inherited events.
10107 * See perf_output_read().
10109 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
10112 if (!has_branch_stack(event))
10113 event->attr.branch_sample_type = 0;
10115 if (cgroup_fd != -1) {
10116 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
10121 pmu = perf_init_event(event);
10123 err = PTR_ERR(pmu);
10127 err = exclusive_event_init(event);
10131 if (has_addr_filter(event)) {
10132 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
10133 sizeof(unsigned long),
10135 if (!event->addr_filters_offs) {
10141 * Clone the parent's vma offsets: they are valid until exec()
10142 * even if the mm is not shared with the parent.
10144 if (event->parent) {
10145 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10147 raw_spin_lock_irq(&ifh->lock);
10148 memcpy(event->addr_filters_offs,
10149 event->parent->addr_filters_offs,
10150 pmu->nr_addr_filters * sizeof(unsigned long));
10151 raw_spin_unlock_irq(&ifh->lock);
10154 /* force hw sync on the address filters */
10155 event->addr_filters_gen = 1;
10158 if (!event->parent) {
10159 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
10160 err = get_callchain_buffers(attr->sample_max_stack);
10162 goto err_addr_filters;
10166 /* symmetric to unaccount_event() in _free_event() */
10167 account_event(event);
10172 kfree(event->addr_filters_offs);
10175 exclusive_event_destroy(event);
10178 if (event->destroy)
10179 event->destroy(event);
10180 module_put(pmu->module);
10182 if (is_cgroup_event(event))
10183 perf_detach_cgroup(event);
10185 put_pid_ns(event->ns);
10186 if (event->hw.target)
10187 put_task_struct(event->hw.target);
10190 return ERR_PTR(err);
10193 static int perf_copy_attr(struct perf_event_attr __user *uattr,
10194 struct perf_event_attr *attr)
10199 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
10203 * zero the full structure, so that a short copy will be nice.
10205 memset(attr, 0, sizeof(*attr));
10207 ret = get_user(size, &uattr->size);
10211 if (size > PAGE_SIZE) /* silly large */
10214 if (!size) /* abi compat */
10215 size = PERF_ATTR_SIZE_VER0;
10217 if (size < PERF_ATTR_SIZE_VER0)
10221 * If we're handed a bigger struct than we know of,
10222 * ensure all the unknown bits are 0 - i.e. new
10223 * user-space does not rely on any kernel feature
10224 * extensions we dont know about yet.
10226 if (size > sizeof(*attr)) {
10227 unsigned char __user *addr;
10228 unsigned char __user *end;
10231 addr = (void __user *)uattr + sizeof(*attr);
10232 end = (void __user *)uattr + size;
10234 for (; addr < end; addr++) {
10235 ret = get_user(val, addr);
10241 size = sizeof(*attr);
10244 ret = copy_from_user(attr, uattr, size);
10250 if (attr->__reserved_1)
10253 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
10256 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
10259 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
10260 u64 mask = attr->branch_sample_type;
10262 /* only using defined bits */
10263 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
10266 /* at least one branch bit must be set */
10267 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
10270 /* propagate priv level, when not set for branch */
10271 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
10273 /* exclude_kernel checked on syscall entry */
10274 if (!attr->exclude_kernel)
10275 mask |= PERF_SAMPLE_BRANCH_KERNEL;
10277 if (!attr->exclude_user)
10278 mask |= PERF_SAMPLE_BRANCH_USER;
10280 if (!attr->exclude_hv)
10281 mask |= PERF_SAMPLE_BRANCH_HV;
10283 * adjust user setting (for HW filter setup)
10285 attr->branch_sample_type = mask;
10287 /* privileged levels capture (kernel, hv): check permissions */
10288 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
10289 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10293 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
10294 ret = perf_reg_validate(attr->sample_regs_user);
10299 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
10300 if (!arch_perf_have_user_stack_dump())
10304 * We have __u32 type for the size, but so far
10305 * we can only use __u16 as maximum due to the
10306 * __u16 sample size limit.
10308 if (attr->sample_stack_user >= USHRT_MAX)
10310 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
10314 if (!attr->sample_max_stack)
10315 attr->sample_max_stack = sysctl_perf_event_max_stack;
10317 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
10318 ret = perf_reg_validate(attr->sample_regs_intr);
10323 put_user(sizeof(*attr), &uattr->size);
10329 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
10331 struct ring_buffer *rb = NULL;
10337 /* don't allow circular references */
10338 if (event == output_event)
10342 * Don't allow cross-cpu buffers
10344 if (output_event->cpu != event->cpu)
10348 * If its not a per-cpu rb, it must be the same task.
10350 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
10354 * Mixing clocks in the same buffer is trouble you don't need.
10356 if (output_event->clock != event->clock)
10360 * Either writing ring buffer from beginning or from end.
10361 * Mixing is not allowed.
10363 if (is_write_backward(output_event) != is_write_backward(event))
10367 * If both events generate aux data, they must be on the same PMU
10369 if (has_aux(event) && has_aux(output_event) &&
10370 event->pmu != output_event->pmu)
10374 mutex_lock(&event->mmap_mutex);
10375 /* Can't redirect output if we've got an active mmap() */
10376 if (atomic_read(&event->mmap_count))
10379 if (output_event) {
10380 /* get the rb we want to redirect to */
10381 rb = ring_buffer_get(output_event);
10386 ring_buffer_attach(event, rb);
10390 mutex_unlock(&event->mmap_mutex);
10396 static void mutex_lock_double(struct mutex *a, struct mutex *b)
10402 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
10405 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
10407 bool nmi_safe = false;
10410 case CLOCK_MONOTONIC:
10411 event->clock = &ktime_get_mono_fast_ns;
10415 case CLOCK_MONOTONIC_RAW:
10416 event->clock = &ktime_get_raw_fast_ns;
10420 case CLOCK_REALTIME:
10421 event->clock = &ktime_get_real_ns;
10424 case CLOCK_BOOTTIME:
10425 event->clock = &ktime_get_boot_ns;
10429 event->clock = &ktime_get_tai_ns;
10436 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
10443 * Variation on perf_event_ctx_lock_nested(), except we take two context
10446 static struct perf_event_context *
10447 __perf_event_ctx_lock_double(struct perf_event *group_leader,
10448 struct perf_event_context *ctx)
10450 struct perf_event_context *gctx;
10454 gctx = READ_ONCE(group_leader->ctx);
10455 if (!atomic_inc_not_zero(&gctx->refcount)) {
10461 mutex_lock_double(&gctx->mutex, &ctx->mutex);
10463 if (group_leader->ctx != gctx) {
10464 mutex_unlock(&ctx->mutex);
10465 mutex_unlock(&gctx->mutex);
10474 * sys_perf_event_open - open a performance event, associate it to a task/cpu
10476 * @attr_uptr: event_id type attributes for monitoring/sampling
10479 * @group_fd: group leader event fd
10481 SYSCALL_DEFINE5(perf_event_open,
10482 struct perf_event_attr __user *, attr_uptr,
10483 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
10485 struct perf_event *group_leader = NULL, *output_event = NULL;
10486 struct perf_event *event, *sibling;
10487 struct perf_event_attr attr;
10488 struct perf_event_context *ctx, *uninitialized_var(gctx);
10489 struct file *event_file = NULL;
10490 struct fd group = {NULL, 0};
10491 struct task_struct *task = NULL;
10494 int move_group = 0;
10496 int f_flags = O_RDWR;
10497 int cgroup_fd = -1;
10499 /* for future expandability... */
10500 if (flags & ~PERF_FLAG_ALL)
10503 err = perf_copy_attr(attr_uptr, &attr);
10507 if (!attr.exclude_kernel) {
10508 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10512 if (attr.namespaces) {
10513 if (!capable(CAP_SYS_ADMIN))
10518 if (attr.sample_freq > sysctl_perf_event_sample_rate)
10521 if (attr.sample_period & (1ULL << 63))
10525 /* Only privileged users can get physical addresses */
10526 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
10527 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10531 * In cgroup mode, the pid argument is used to pass the fd
10532 * opened to the cgroup directory in cgroupfs. The cpu argument
10533 * designates the cpu on which to monitor threads from that
10536 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
10539 if (flags & PERF_FLAG_FD_CLOEXEC)
10540 f_flags |= O_CLOEXEC;
10542 event_fd = get_unused_fd_flags(f_flags);
10546 if (group_fd != -1) {
10547 err = perf_fget_light(group_fd, &group);
10550 group_leader = group.file->private_data;
10551 if (flags & PERF_FLAG_FD_OUTPUT)
10552 output_event = group_leader;
10553 if (flags & PERF_FLAG_FD_NO_GROUP)
10554 group_leader = NULL;
10557 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
10558 task = find_lively_task_by_vpid(pid);
10559 if (IS_ERR(task)) {
10560 err = PTR_ERR(task);
10565 if (task && group_leader &&
10566 group_leader->attr.inherit != attr.inherit) {
10572 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
10577 * Reuse ptrace permission checks for now.
10579 * We must hold cred_guard_mutex across this and any potential
10580 * perf_install_in_context() call for this new event to
10581 * serialize against exec() altering our credentials (and the
10582 * perf_event_exit_task() that could imply).
10585 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
10589 if (flags & PERF_FLAG_PID_CGROUP)
10592 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
10593 NULL, NULL, cgroup_fd);
10594 if (IS_ERR(event)) {
10595 err = PTR_ERR(event);
10599 if (is_sampling_event(event)) {
10600 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
10607 * Special case software events and allow them to be part of
10608 * any hardware group.
10612 if (attr.use_clockid) {
10613 err = perf_event_set_clock(event, attr.clockid);
10618 if (pmu->task_ctx_nr == perf_sw_context)
10619 event->event_caps |= PERF_EV_CAP_SOFTWARE;
10621 if (group_leader) {
10622 if (is_software_event(event) &&
10623 !in_software_context(group_leader)) {
10625 * If the event is a sw event, but the group_leader
10626 * is on hw context.
10628 * Allow the addition of software events to hw
10629 * groups, this is safe because software events
10630 * never fail to schedule.
10632 pmu = group_leader->ctx->pmu;
10633 } else if (!is_software_event(event) &&
10634 is_software_event(group_leader) &&
10635 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10637 * In case the group is a pure software group, and we
10638 * try to add a hardware event, move the whole group to
10639 * the hardware context.
10646 * Get the target context (task or percpu):
10648 ctx = find_get_context(pmu, task, event);
10650 err = PTR_ERR(ctx);
10655 * Look up the group leader (we will attach this event to it):
10657 if (group_leader) {
10661 * Do not allow a recursive hierarchy (this new sibling
10662 * becoming part of another group-sibling):
10664 if (group_leader->group_leader != group_leader)
10667 /* All events in a group should have the same clock */
10668 if (group_leader->clock != event->clock)
10672 * Make sure we're both events for the same CPU;
10673 * grouping events for different CPUs is broken; since
10674 * you can never concurrently schedule them anyhow.
10676 if (group_leader->cpu != event->cpu)
10680 * Make sure we're both on the same task, or both
10683 if (group_leader->ctx->task != ctx->task)
10687 * Do not allow to attach to a group in a different task
10688 * or CPU context. If we're moving SW events, we'll fix
10689 * this up later, so allow that.
10691 if (!move_group && group_leader->ctx != ctx)
10695 * Only a group leader can be exclusive or pinned
10697 if (attr.exclusive || attr.pinned)
10701 if (output_event) {
10702 err = perf_event_set_output(event, output_event);
10707 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10709 if (IS_ERR(event_file)) {
10710 err = PTR_ERR(event_file);
10716 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10718 if (gctx->task == TASK_TOMBSTONE) {
10724 * Check if we raced against another sys_perf_event_open() call
10725 * moving the software group underneath us.
10727 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10729 * If someone moved the group out from under us, check
10730 * if this new event wound up on the same ctx, if so
10731 * its the regular !move_group case, otherwise fail.
10737 perf_event_ctx_unlock(group_leader, gctx);
10743 * Failure to create exclusive events returns -EBUSY.
10746 if (!exclusive_event_installable(group_leader, ctx))
10749 for_each_sibling_event(sibling, group_leader) {
10750 if (!exclusive_event_installable(sibling, ctx))
10754 mutex_lock(&ctx->mutex);
10757 if (ctx->task == TASK_TOMBSTONE) {
10762 if (!perf_event_validate_size(event)) {
10769 * Check if the @cpu we're creating an event for is online.
10771 * We use the perf_cpu_context::ctx::mutex to serialize against
10772 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10774 struct perf_cpu_context *cpuctx =
10775 container_of(ctx, struct perf_cpu_context, ctx);
10777 if (!cpuctx->online) {
10785 * Must be under the same ctx::mutex as perf_install_in_context(),
10786 * because we need to serialize with concurrent event creation.
10788 if (!exclusive_event_installable(event, ctx)) {
10793 WARN_ON_ONCE(ctx->parent_ctx);
10796 * This is the point on no return; we cannot fail hereafter. This is
10797 * where we start modifying current state.
10802 * See perf_event_ctx_lock() for comments on the details
10803 * of swizzling perf_event::ctx.
10805 perf_remove_from_context(group_leader, 0);
10808 for_each_sibling_event(sibling, group_leader) {
10809 perf_remove_from_context(sibling, 0);
10814 * Wait for everybody to stop referencing the events through
10815 * the old lists, before installing it on new lists.
10820 * Install the group siblings before the group leader.
10822 * Because a group leader will try and install the entire group
10823 * (through the sibling list, which is still in-tact), we can
10824 * end up with siblings installed in the wrong context.
10826 * By installing siblings first we NO-OP because they're not
10827 * reachable through the group lists.
10829 for_each_sibling_event(sibling, group_leader) {
10830 perf_event__state_init(sibling);
10831 perf_install_in_context(ctx, sibling, sibling->cpu);
10836 * Removing from the context ends up with disabled
10837 * event. What we want here is event in the initial
10838 * startup state, ready to be add into new context.
10840 perf_event__state_init(group_leader);
10841 perf_install_in_context(ctx, group_leader, group_leader->cpu);
10846 * Precalculate sample_data sizes; do while holding ctx::mutex such
10847 * that we're serialized against further additions and before
10848 * perf_install_in_context() which is the point the event is active and
10849 * can use these values.
10851 perf_event__header_size(event);
10852 perf_event__id_header_size(event);
10854 event->owner = current;
10856 perf_install_in_context(ctx, event, event->cpu);
10857 perf_unpin_context(ctx);
10860 perf_event_ctx_unlock(group_leader, gctx);
10861 mutex_unlock(&ctx->mutex);
10864 mutex_unlock(&task->signal->cred_guard_mutex);
10865 put_task_struct(task);
10868 mutex_lock(¤t->perf_event_mutex);
10869 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10870 mutex_unlock(¤t->perf_event_mutex);
10873 * Drop the reference on the group_event after placing the
10874 * new event on the sibling_list. This ensures destruction
10875 * of the group leader will find the pointer to itself in
10876 * perf_group_detach().
10879 fd_install(event_fd, event_file);
10884 perf_event_ctx_unlock(group_leader, gctx);
10885 mutex_unlock(&ctx->mutex);
10889 perf_unpin_context(ctx);
10893 * If event_file is set, the fput() above will have called ->release()
10894 * and that will take care of freeing the event.
10900 mutex_unlock(&task->signal->cred_guard_mutex);
10903 put_task_struct(task);
10907 put_unused_fd(event_fd);
10912 * perf_event_create_kernel_counter
10914 * @attr: attributes of the counter to create
10915 * @cpu: cpu in which the counter is bound
10916 * @task: task to profile (NULL for percpu)
10918 struct perf_event *
10919 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10920 struct task_struct *task,
10921 perf_overflow_handler_t overflow_handler,
10924 struct perf_event_context *ctx;
10925 struct perf_event *event;
10929 * Get the target context (task or percpu):
10932 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
10933 overflow_handler, context, -1);
10934 if (IS_ERR(event)) {
10935 err = PTR_ERR(event);
10939 /* Mark owner so we could distinguish it from user events. */
10940 event->owner = TASK_TOMBSTONE;
10942 ctx = find_get_context(event->pmu, task, event);
10944 err = PTR_ERR(ctx);
10948 WARN_ON_ONCE(ctx->parent_ctx);
10949 mutex_lock(&ctx->mutex);
10950 if (ctx->task == TASK_TOMBSTONE) {
10957 * Check if the @cpu we're creating an event for is online.
10959 * We use the perf_cpu_context::ctx::mutex to serialize against
10960 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10962 struct perf_cpu_context *cpuctx =
10963 container_of(ctx, struct perf_cpu_context, ctx);
10964 if (!cpuctx->online) {
10970 if (!exclusive_event_installable(event, ctx)) {
10975 perf_install_in_context(ctx, event, event->cpu);
10976 perf_unpin_context(ctx);
10977 mutex_unlock(&ctx->mutex);
10982 mutex_unlock(&ctx->mutex);
10983 perf_unpin_context(ctx);
10988 return ERR_PTR(err);
10990 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
10992 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
10994 struct perf_event_context *src_ctx;
10995 struct perf_event_context *dst_ctx;
10996 struct perf_event *event, *tmp;
10999 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
11000 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
11003 * See perf_event_ctx_lock() for comments on the details
11004 * of swizzling perf_event::ctx.
11006 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
11007 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
11009 perf_remove_from_context(event, 0);
11010 unaccount_event_cpu(event, src_cpu);
11012 list_add(&event->migrate_entry, &events);
11016 * Wait for the events to quiesce before re-instating them.
11021 * Re-instate events in 2 passes.
11023 * Skip over group leaders and only install siblings on this first
11024 * pass, siblings will not get enabled without a leader, however a
11025 * leader will enable its siblings, even if those are still on the old
11028 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11029 if (event->group_leader == event)
11032 list_del(&event->migrate_entry);
11033 if (event->state >= PERF_EVENT_STATE_OFF)
11034 event->state = PERF_EVENT_STATE_INACTIVE;
11035 account_event_cpu(event, dst_cpu);
11036 perf_install_in_context(dst_ctx, event, dst_cpu);
11041 * Once all the siblings are setup properly, install the group leaders
11044 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11045 list_del(&event->migrate_entry);
11046 if (event->state >= PERF_EVENT_STATE_OFF)
11047 event->state = PERF_EVENT_STATE_INACTIVE;
11048 account_event_cpu(event, dst_cpu);
11049 perf_install_in_context(dst_ctx, event, dst_cpu);
11052 mutex_unlock(&dst_ctx->mutex);
11053 mutex_unlock(&src_ctx->mutex);
11055 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
11057 static void sync_child_event(struct perf_event *child_event,
11058 struct task_struct *child)
11060 struct perf_event *parent_event = child_event->parent;
11063 if (child_event->attr.inherit_stat)
11064 perf_event_read_event(child_event, child);
11066 child_val = perf_event_count(child_event);
11069 * Add back the child's count to the parent's count:
11071 atomic64_add(child_val, &parent_event->child_count);
11072 atomic64_add(child_event->total_time_enabled,
11073 &parent_event->child_total_time_enabled);
11074 atomic64_add(child_event->total_time_running,
11075 &parent_event->child_total_time_running);
11079 perf_event_exit_event(struct perf_event *child_event,
11080 struct perf_event_context *child_ctx,
11081 struct task_struct *child)
11083 struct perf_event *parent_event = child_event->parent;
11086 * Do not destroy the 'original' grouping; because of the context
11087 * switch optimization the original events could've ended up in a
11088 * random child task.
11090 * If we were to destroy the original group, all group related
11091 * operations would cease to function properly after this random
11094 * Do destroy all inherited groups, we don't care about those
11095 * and being thorough is better.
11097 raw_spin_lock_irq(&child_ctx->lock);
11098 WARN_ON_ONCE(child_ctx->is_active);
11101 perf_group_detach(child_event);
11102 list_del_event(child_event, child_ctx);
11103 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
11104 raw_spin_unlock_irq(&child_ctx->lock);
11107 * Parent events are governed by their filedesc, retain them.
11109 if (!parent_event) {
11110 perf_event_wakeup(child_event);
11114 * Child events can be cleaned up.
11117 sync_child_event(child_event, child);
11120 * Remove this event from the parent's list
11122 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
11123 mutex_lock(&parent_event->child_mutex);
11124 list_del_init(&child_event->child_list);
11125 mutex_unlock(&parent_event->child_mutex);
11128 * Kick perf_poll() for is_event_hup().
11130 perf_event_wakeup(parent_event);
11131 free_event(child_event);
11132 put_event(parent_event);
11135 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
11137 struct perf_event_context *child_ctx, *clone_ctx = NULL;
11138 struct perf_event *child_event, *next;
11140 WARN_ON_ONCE(child != current);
11142 child_ctx = perf_pin_task_context(child, ctxn);
11147 * In order to reduce the amount of tricky in ctx tear-down, we hold
11148 * ctx::mutex over the entire thing. This serializes against almost
11149 * everything that wants to access the ctx.
11151 * The exception is sys_perf_event_open() /
11152 * perf_event_create_kernel_count() which does find_get_context()
11153 * without ctx::mutex (it cannot because of the move_group double mutex
11154 * lock thing). See the comments in perf_install_in_context().
11156 mutex_lock(&child_ctx->mutex);
11159 * In a single ctx::lock section, de-schedule the events and detach the
11160 * context from the task such that we cannot ever get it scheduled back
11163 raw_spin_lock_irq(&child_ctx->lock);
11164 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
11167 * Now that the context is inactive, destroy the task <-> ctx relation
11168 * and mark the context dead.
11170 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
11171 put_ctx(child_ctx); /* cannot be last */
11172 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
11173 put_task_struct(current); /* cannot be last */
11175 clone_ctx = unclone_ctx(child_ctx);
11176 raw_spin_unlock_irq(&child_ctx->lock);
11179 put_ctx(clone_ctx);
11182 * Report the task dead after unscheduling the events so that we
11183 * won't get any samples after PERF_RECORD_EXIT. We can however still
11184 * get a few PERF_RECORD_READ events.
11186 perf_event_task(child, child_ctx, 0);
11188 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
11189 perf_event_exit_event(child_event, child_ctx, child);
11191 mutex_unlock(&child_ctx->mutex);
11193 put_ctx(child_ctx);
11197 * When a child task exits, feed back event values to parent events.
11199 * Can be called with cred_guard_mutex held when called from
11200 * install_exec_creds().
11202 void perf_event_exit_task(struct task_struct *child)
11204 struct perf_event *event, *tmp;
11207 mutex_lock(&child->perf_event_mutex);
11208 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
11210 list_del_init(&event->owner_entry);
11213 * Ensure the list deletion is visible before we clear
11214 * the owner, closes a race against perf_release() where
11215 * we need to serialize on the owner->perf_event_mutex.
11217 smp_store_release(&event->owner, NULL);
11219 mutex_unlock(&child->perf_event_mutex);
11221 for_each_task_context_nr(ctxn)
11222 perf_event_exit_task_context(child, ctxn);
11225 * The perf_event_exit_task_context calls perf_event_task
11226 * with child's task_ctx, which generates EXIT events for
11227 * child contexts and sets child->perf_event_ctxp[] to NULL.
11228 * At this point we need to send EXIT events to cpu contexts.
11230 perf_event_task(child, NULL, 0);
11233 static void perf_free_event(struct perf_event *event,
11234 struct perf_event_context *ctx)
11236 struct perf_event *parent = event->parent;
11238 if (WARN_ON_ONCE(!parent))
11241 mutex_lock(&parent->child_mutex);
11242 list_del_init(&event->child_list);
11243 mutex_unlock(&parent->child_mutex);
11247 raw_spin_lock_irq(&ctx->lock);
11248 perf_group_detach(event);
11249 list_del_event(event, ctx);
11250 raw_spin_unlock_irq(&ctx->lock);
11255 * Free a context as created by inheritance by perf_event_init_task() below,
11256 * used by fork() in case of fail.
11258 * Even though the task has never lived, the context and events have been
11259 * exposed through the child_list, so we must take care tearing it all down.
11261 void perf_event_free_task(struct task_struct *task)
11263 struct perf_event_context *ctx;
11264 struct perf_event *event, *tmp;
11267 for_each_task_context_nr(ctxn) {
11268 ctx = task->perf_event_ctxp[ctxn];
11272 mutex_lock(&ctx->mutex);
11273 raw_spin_lock_irq(&ctx->lock);
11275 * Destroy the task <-> ctx relation and mark the context dead.
11277 * This is important because even though the task hasn't been
11278 * exposed yet the context has been (through child_list).
11280 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
11281 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
11282 put_task_struct(task); /* cannot be last */
11283 raw_spin_unlock_irq(&ctx->lock);
11285 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
11286 perf_free_event(event, ctx);
11288 mutex_unlock(&ctx->mutex);
11291 * perf_event_release_kernel() could've stolen some of our
11292 * child events and still have them on its free_list. In that
11293 * case we must wait for these events to have been freed (in
11294 * particular all their references to this task must've been
11297 * Without this copy_process() will unconditionally free this
11298 * task (irrespective of its reference count) and
11299 * _free_event()'s put_task_struct(event->hw.target) will be a
11302 * Wait for all events to drop their context reference.
11304 wait_var_event(&ctx->refcount, atomic_read(&ctx->refcount) == 1);
11305 put_ctx(ctx); /* must be last */
11309 void perf_event_delayed_put(struct task_struct *task)
11313 for_each_task_context_nr(ctxn)
11314 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
11317 struct file *perf_event_get(unsigned int fd)
11321 file = fget_raw(fd);
11323 return ERR_PTR(-EBADF);
11325 if (file->f_op != &perf_fops) {
11327 return ERR_PTR(-EBADF);
11333 const struct perf_event *perf_get_event(struct file *file)
11335 if (file->f_op != &perf_fops)
11336 return ERR_PTR(-EINVAL);
11338 return file->private_data;
11341 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
11344 return ERR_PTR(-EINVAL);
11346 return &event->attr;
11350 * Inherit an event from parent task to child task.
11353 * - valid pointer on success
11354 * - NULL for orphaned events
11355 * - IS_ERR() on error
11357 static struct perf_event *
11358 inherit_event(struct perf_event *parent_event,
11359 struct task_struct *parent,
11360 struct perf_event_context *parent_ctx,
11361 struct task_struct *child,
11362 struct perf_event *group_leader,
11363 struct perf_event_context *child_ctx)
11365 enum perf_event_state parent_state = parent_event->state;
11366 struct perf_event *child_event;
11367 unsigned long flags;
11370 * Instead of creating recursive hierarchies of events,
11371 * we link inherited events back to the original parent,
11372 * which has a filp for sure, which we use as the reference
11375 if (parent_event->parent)
11376 parent_event = parent_event->parent;
11378 child_event = perf_event_alloc(&parent_event->attr,
11381 group_leader, parent_event,
11383 if (IS_ERR(child_event))
11384 return child_event;
11387 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
11388 !child_ctx->task_ctx_data) {
11389 struct pmu *pmu = child_event->pmu;
11391 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
11393 if (!child_ctx->task_ctx_data) {
11394 free_event(child_event);
11395 return ERR_PTR(-ENOMEM);
11400 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
11401 * must be under the same lock in order to serialize against
11402 * perf_event_release_kernel(), such that either we must observe
11403 * is_orphaned_event() or they will observe us on the child_list.
11405 mutex_lock(&parent_event->child_mutex);
11406 if (is_orphaned_event(parent_event) ||
11407 !atomic_long_inc_not_zero(&parent_event->refcount)) {
11408 mutex_unlock(&parent_event->child_mutex);
11409 /* task_ctx_data is freed with child_ctx */
11410 free_event(child_event);
11414 get_ctx(child_ctx);
11417 * Make the child state follow the state of the parent event,
11418 * not its attr.disabled bit. We hold the parent's mutex,
11419 * so we won't race with perf_event_{en, dis}able_family.
11421 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
11422 child_event->state = PERF_EVENT_STATE_INACTIVE;
11424 child_event->state = PERF_EVENT_STATE_OFF;
11426 if (parent_event->attr.freq) {
11427 u64 sample_period = parent_event->hw.sample_period;
11428 struct hw_perf_event *hwc = &child_event->hw;
11430 hwc->sample_period = sample_period;
11431 hwc->last_period = sample_period;
11433 local64_set(&hwc->period_left, sample_period);
11436 child_event->ctx = child_ctx;
11437 child_event->overflow_handler = parent_event->overflow_handler;
11438 child_event->overflow_handler_context
11439 = parent_event->overflow_handler_context;
11442 * Precalculate sample_data sizes
11444 perf_event__header_size(child_event);
11445 perf_event__id_header_size(child_event);
11448 * Link it up in the child's context:
11450 raw_spin_lock_irqsave(&child_ctx->lock, flags);
11451 add_event_to_ctx(child_event, child_ctx);
11452 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
11455 * Link this into the parent event's child list
11457 list_add_tail(&child_event->child_list, &parent_event->child_list);
11458 mutex_unlock(&parent_event->child_mutex);
11460 return child_event;
11464 * Inherits an event group.
11466 * This will quietly suppress orphaned events; !inherit_event() is not an error.
11467 * This matches with perf_event_release_kernel() removing all child events.
11473 static int inherit_group(struct perf_event *parent_event,
11474 struct task_struct *parent,
11475 struct perf_event_context *parent_ctx,
11476 struct task_struct *child,
11477 struct perf_event_context *child_ctx)
11479 struct perf_event *leader;
11480 struct perf_event *sub;
11481 struct perf_event *child_ctr;
11483 leader = inherit_event(parent_event, parent, parent_ctx,
11484 child, NULL, child_ctx);
11485 if (IS_ERR(leader))
11486 return PTR_ERR(leader);
11488 * @leader can be NULL here because of is_orphaned_event(). In this
11489 * case inherit_event() will create individual events, similar to what
11490 * perf_group_detach() would do anyway.
11492 for_each_sibling_event(sub, parent_event) {
11493 child_ctr = inherit_event(sub, parent, parent_ctx,
11494 child, leader, child_ctx);
11495 if (IS_ERR(child_ctr))
11496 return PTR_ERR(child_ctr);
11502 * Creates the child task context and tries to inherit the event-group.
11504 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
11505 * inherited_all set when we 'fail' to inherit an orphaned event; this is
11506 * consistent with perf_event_release_kernel() removing all child events.
11513 inherit_task_group(struct perf_event *event, struct task_struct *parent,
11514 struct perf_event_context *parent_ctx,
11515 struct task_struct *child, int ctxn,
11516 int *inherited_all)
11519 struct perf_event_context *child_ctx;
11521 if (!event->attr.inherit) {
11522 *inherited_all = 0;
11526 child_ctx = child->perf_event_ctxp[ctxn];
11529 * This is executed from the parent task context, so
11530 * inherit events that have been marked for cloning.
11531 * First allocate and initialize a context for the
11534 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
11538 child->perf_event_ctxp[ctxn] = child_ctx;
11541 ret = inherit_group(event, parent, parent_ctx,
11545 *inherited_all = 0;
11551 * Initialize the perf_event context in task_struct
11553 static int perf_event_init_context(struct task_struct *child, int ctxn)
11555 struct perf_event_context *child_ctx, *parent_ctx;
11556 struct perf_event_context *cloned_ctx;
11557 struct perf_event *event;
11558 struct task_struct *parent = current;
11559 int inherited_all = 1;
11560 unsigned long flags;
11563 if (likely(!parent->perf_event_ctxp[ctxn]))
11567 * If the parent's context is a clone, pin it so it won't get
11568 * swapped under us.
11570 parent_ctx = perf_pin_task_context(parent, ctxn);
11575 * No need to check if parent_ctx != NULL here; since we saw
11576 * it non-NULL earlier, the only reason for it to become NULL
11577 * is if we exit, and since we're currently in the middle of
11578 * a fork we can't be exiting at the same time.
11582 * Lock the parent list. No need to lock the child - not PID
11583 * hashed yet and not running, so nobody can access it.
11585 mutex_lock(&parent_ctx->mutex);
11588 * We dont have to disable NMIs - we are only looking at
11589 * the list, not manipulating it:
11591 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
11592 ret = inherit_task_group(event, parent, parent_ctx,
11593 child, ctxn, &inherited_all);
11599 * We can't hold ctx->lock when iterating the ->flexible_group list due
11600 * to allocations, but we need to prevent rotation because
11601 * rotate_ctx() will change the list from interrupt context.
11603 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11604 parent_ctx->rotate_disable = 1;
11605 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11607 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
11608 ret = inherit_task_group(event, parent, parent_ctx,
11609 child, ctxn, &inherited_all);
11614 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11615 parent_ctx->rotate_disable = 0;
11617 child_ctx = child->perf_event_ctxp[ctxn];
11619 if (child_ctx && inherited_all) {
11621 * Mark the child context as a clone of the parent
11622 * context, or of whatever the parent is a clone of.
11624 * Note that if the parent is a clone, the holding of
11625 * parent_ctx->lock avoids it from being uncloned.
11627 cloned_ctx = parent_ctx->parent_ctx;
11629 child_ctx->parent_ctx = cloned_ctx;
11630 child_ctx->parent_gen = parent_ctx->parent_gen;
11632 child_ctx->parent_ctx = parent_ctx;
11633 child_ctx->parent_gen = parent_ctx->generation;
11635 get_ctx(child_ctx->parent_ctx);
11638 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11640 mutex_unlock(&parent_ctx->mutex);
11642 perf_unpin_context(parent_ctx);
11643 put_ctx(parent_ctx);
11649 * Initialize the perf_event context in task_struct
11651 int perf_event_init_task(struct task_struct *child)
11655 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
11656 mutex_init(&child->perf_event_mutex);
11657 INIT_LIST_HEAD(&child->perf_event_list);
11659 for_each_task_context_nr(ctxn) {
11660 ret = perf_event_init_context(child, ctxn);
11662 perf_event_free_task(child);
11670 static void __init perf_event_init_all_cpus(void)
11672 struct swevent_htable *swhash;
11675 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
11677 for_each_possible_cpu(cpu) {
11678 swhash = &per_cpu(swevent_htable, cpu);
11679 mutex_init(&swhash->hlist_mutex);
11680 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
11682 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
11683 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
11685 #ifdef CONFIG_CGROUP_PERF
11686 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
11688 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
11692 void perf_swevent_init_cpu(unsigned int cpu)
11694 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
11696 mutex_lock(&swhash->hlist_mutex);
11697 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
11698 struct swevent_hlist *hlist;
11700 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
11702 rcu_assign_pointer(swhash->swevent_hlist, hlist);
11704 mutex_unlock(&swhash->hlist_mutex);
11707 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11708 static void __perf_event_exit_context(void *__info)
11710 struct perf_event_context *ctx = __info;
11711 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
11712 struct perf_event *event;
11714 raw_spin_lock(&ctx->lock);
11715 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
11716 list_for_each_entry(event, &ctx->event_list, event_entry)
11717 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
11718 raw_spin_unlock(&ctx->lock);
11721 static void perf_event_exit_cpu_context(int cpu)
11723 struct perf_cpu_context *cpuctx;
11724 struct perf_event_context *ctx;
11727 mutex_lock(&pmus_lock);
11728 list_for_each_entry(pmu, &pmus, entry) {
11729 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11730 ctx = &cpuctx->ctx;
11732 mutex_lock(&ctx->mutex);
11733 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11734 cpuctx->online = 0;
11735 mutex_unlock(&ctx->mutex);
11737 cpumask_clear_cpu(cpu, perf_online_mask);
11738 mutex_unlock(&pmus_lock);
11742 static void perf_event_exit_cpu_context(int cpu) { }
11746 int perf_event_init_cpu(unsigned int cpu)
11748 struct perf_cpu_context *cpuctx;
11749 struct perf_event_context *ctx;
11752 perf_swevent_init_cpu(cpu);
11754 mutex_lock(&pmus_lock);
11755 cpumask_set_cpu(cpu, perf_online_mask);
11756 list_for_each_entry(pmu, &pmus, entry) {
11757 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11758 ctx = &cpuctx->ctx;
11760 mutex_lock(&ctx->mutex);
11761 cpuctx->online = 1;
11762 mutex_unlock(&ctx->mutex);
11764 mutex_unlock(&pmus_lock);
11769 int perf_event_exit_cpu(unsigned int cpu)
11771 perf_event_exit_cpu_context(cpu);
11776 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11780 for_each_online_cpu(cpu)
11781 perf_event_exit_cpu(cpu);
11787 * Run the perf reboot notifier at the very last possible moment so that
11788 * the generic watchdog code runs as long as possible.
11790 static struct notifier_block perf_reboot_notifier = {
11791 .notifier_call = perf_reboot,
11792 .priority = INT_MIN,
11795 void __init perf_event_init(void)
11799 idr_init(&pmu_idr);
11801 perf_event_init_all_cpus();
11802 init_srcu_struct(&pmus_srcu);
11803 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11804 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11805 perf_pmu_register(&perf_task_clock, NULL, -1);
11806 perf_tp_register();
11807 perf_event_init_cpu(smp_processor_id());
11808 register_reboot_notifier(&perf_reboot_notifier);
11810 ret = init_hw_breakpoint();
11811 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11814 * Build time assertion that we keep the data_head at the intended
11815 * location. IOW, validation we got the __reserved[] size right.
11817 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
11821 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
11824 struct perf_pmu_events_attr *pmu_attr =
11825 container_of(attr, struct perf_pmu_events_attr, attr);
11827 if (pmu_attr->event_str)
11828 return sprintf(page, "%s\n", pmu_attr->event_str);
11832 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
11834 static int __init perf_event_sysfs_init(void)
11839 mutex_lock(&pmus_lock);
11841 ret = bus_register(&pmu_bus);
11845 list_for_each_entry(pmu, &pmus, entry) {
11846 if (!pmu->name || pmu->type < 0)
11849 ret = pmu_dev_alloc(pmu);
11850 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
11852 pmu_bus_running = 1;
11856 mutex_unlock(&pmus_lock);
11860 device_initcall(perf_event_sysfs_init);
11862 #ifdef CONFIG_CGROUP_PERF
11863 static struct cgroup_subsys_state *
11864 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
11866 struct perf_cgroup *jc;
11868 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
11870 return ERR_PTR(-ENOMEM);
11872 jc->info = alloc_percpu(struct perf_cgroup_info);
11875 return ERR_PTR(-ENOMEM);
11881 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
11883 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
11885 free_percpu(jc->info);
11889 static int __perf_cgroup_move(void *info)
11891 struct task_struct *task = info;
11893 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
11898 static void perf_cgroup_attach(struct cgroup_taskset *tset)
11900 struct task_struct *task;
11901 struct cgroup_subsys_state *css;
11903 cgroup_taskset_for_each(task, css, tset)
11904 task_function_call(task, __perf_cgroup_move, task);
11907 struct cgroup_subsys perf_event_cgrp_subsys = {
11908 .css_alloc = perf_cgroup_css_alloc,
11909 .css_free = perf_cgroup_css_free,
11910 .attach = perf_cgroup_attach,
11912 * Implicitly enable on dfl hierarchy so that perf events can
11913 * always be filtered by cgroup2 path as long as perf_event
11914 * controller is not mounted on a legacy hierarchy.
11916 .implicit_on_dfl = true,
11919 #endif /* CONFIG_CGROUP_PERF */