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
400 * 3 - disallow all unpriv perf event use
402 #ifdef CONFIG_SECURITY_PERF_EVENTS_RESTRICT
403 int sysctl_perf_event_paranoid __read_mostly
= 3;
405 int sysctl_perf_event_paranoid __read_mostly
= 1;
408 /* Minimum for 512 kiB + 1 user control page */
409 int sysctl_perf_event_mlock __read_mostly
= 512 + (PAGE_SIZE
/ 1024); /* 'free' kiB per user */
412 * max perf event sample rate
414 #define DEFAULT_MAX_SAMPLE_RATE 100000
415 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
416 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
418 int sysctl_perf_event_sample_rate __read_mostly
= DEFAULT_MAX_SAMPLE_RATE
;
420 static int max_samples_per_tick __read_mostly
= DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE
, HZ
);
421 static int perf_sample_period_ns __read_mostly
= DEFAULT_SAMPLE_PERIOD_NS
;
423 static int perf_sample_allowed_ns __read_mostly
=
424 DEFAULT_SAMPLE_PERIOD_NS
* DEFAULT_CPU_TIME_MAX_PERCENT
/ 100;
426 static void update_perf_cpu_limits(void)
428 u64 tmp
= perf_sample_period_ns
;
430 tmp
*= sysctl_perf_cpu_time_max_percent
;
431 tmp
= div_u64(tmp
, 100);
435 WRITE_ONCE(perf_sample_allowed_ns
, tmp
);
438 static int perf_rotate_context(struct perf_cpu_context
*cpuctx
);
440 int perf_proc_update_handler(struct ctl_table
*table
, int write
,
441 void __user
*buffer
, size_t *lenp
,
445 int perf_cpu
= sysctl_perf_cpu_time_max_percent
;
447 * If throttling is disabled don't allow the write:
449 if (write
&& (perf_cpu
== 100 || perf_cpu
== 0))
452 ret
= proc_dointvec_minmax(table
, write
, buffer
, lenp
, ppos
);
456 max_samples_per_tick
= DIV_ROUND_UP(sysctl_perf_event_sample_rate
, HZ
);
457 perf_sample_period_ns
= NSEC_PER_SEC
/ sysctl_perf_event_sample_rate
;
458 update_perf_cpu_limits();
463 int sysctl_perf_cpu_time_max_percent __read_mostly
= DEFAULT_CPU_TIME_MAX_PERCENT
;
465 int perf_cpu_time_max_percent_handler(struct ctl_table
*table
, int write
,
466 void __user
*buffer
, size_t *lenp
,
469 int ret
= proc_dointvec_minmax(table
, write
, buffer
, lenp
, ppos
);
474 if (sysctl_perf_cpu_time_max_percent
== 100 ||
475 sysctl_perf_cpu_time_max_percent
== 0) {
477 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
478 WRITE_ONCE(perf_sample_allowed_ns
, 0);
480 update_perf_cpu_limits();
487 * perf samples are done in some very critical code paths (NMIs).
488 * If they take too much CPU time, the system can lock up and not
489 * get any real work done. This will drop the sample rate when
490 * we detect that events are taking too long.
492 #define NR_ACCUMULATED_SAMPLES 128
493 static DEFINE_PER_CPU(u64
, running_sample_length
);
495 static u64 __report_avg
;
496 static u64 __report_allowed
;
498 static void perf_duration_warn(struct irq_work
*w
)
500 printk_ratelimited(KERN_INFO
501 "perf: interrupt took too long (%lld > %lld), lowering "
502 "kernel.perf_event_max_sample_rate to %d\n",
503 __report_avg
, __report_allowed
,
504 sysctl_perf_event_sample_rate
);
507 static DEFINE_IRQ_WORK(perf_duration_work
, perf_duration_warn
);
509 void perf_sample_event_took(u64 sample_len_ns
)
511 u64 max_len
= READ_ONCE(perf_sample_allowed_ns
);
519 /* Decay the counter by 1 average sample. */
520 running_len
= __this_cpu_read(running_sample_length
);
521 running_len
-= running_len
/NR_ACCUMULATED_SAMPLES
;
522 running_len
+= sample_len_ns
;
523 __this_cpu_write(running_sample_length
, running_len
);
526 * Note: this will be biased artifically low until we have
527 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
528 * from having to maintain a count.
530 avg_len
= running_len
/NR_ACCUMULATED_SAMPLES
;
531 if (avg_len
<= max_len
)
534 __report_avg
= avg_len
;
535 __report_allowed
= max_len
;
538 * Compute a throttle threshold 25% below the current duration.
540 avg_len
+= avg_len
/ 4;
541 max
= (TICK_NSEC
/ 100) * sysctl_perf_cpu_time_max_percent
;
547 WRITE_ONCE(perf_sample_allowed_ns
, avg_len
);
548 WRITE_ONCE(max_samples_per_tick
, max
);
550 sysctl_perf_event_sample_rate
= max
* HZ
;
551 perf_sample_period_ns
= NSEC_PER_SEC
/ sysctl_perf_event_sample_rate
;
553 if (!irq_work_queue(&perf_duration_work
)) {
554 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
555 "kernel.perf_event_max_sample_rate to %d\n",
556 __report_avg
, __report_allowed
,
557 sysctl_perf_event_sample_rate
);
561 static atomic64_t perf_event_id
;
563 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
564 enum event_type_t event_type
);
566 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
567 enum event_type_t event_type
,
568 struct task_struct
*task
);
570 static void update_context_time(struct perf_event_context
*ctx
);
571 static u64
perf_event_time(struct perf_event
*event
);
573 void __weak
perf_event_print_debug(void) { }
575 extern __weak
const char *perf_pmu_name(void)
580 static inline u64
perf_clock(void)
582 return local_clock();
585 static inline u64
perf_event_clock(struct perf_event
*event
)
587 return event
->clock();
591 * State based event timekeeping...
593 * The basic idea is to use event->state to determine which (if any) time
594 * fields to increment with the current delta. This means we only need to
595 * update timestamps when we change state or when they are explicitly requested
598 * Event groups make things a little more complicated, but not terribly so. The
599 * rules for a group are that if the group leader is OFF the entire group is
600 * OFF, irrespecive of what the group member states are. This results in
601 * __perf_effective_state().
603 * A futher ramification is that when a group leader flips between OFF and
604 * !OFF, we need to update all group member times.
607 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
608 * need to make sure the relevant context time is updated before we try and
609 * update our timestamps.
612 static __always_inline
enum perf_event_state
613 __perf_effective_state(struct perf_event
*event
)
615 struct perf_event
*leader
= event
->group_leader
;
617 if (leader
->state
<= PERF_EVENT_STATE_OFF
)
618 return leader
->state
;
623 static __always_inline
void
624 __perf_update_times(struct perf_event
*event
, u64 now
, u64
*enabled
, u64
*running
)
626 enum perf_event_state state
= __perf_effective_state(event
);
627 u64 delta
= now
- event
->tstamp
;
629 *enabled
= event
->total_time_enabled
;
630 if (state
>= PERF_EVENT_STATE_INACTIVE
)
633 *running
= event
->total_time_running
;
634 if (state
>= PERF_EVENT_STATE_ACTIVE
)
638 static void perf_event_update_time(struct perf_event
*event
)
640 u64 now
= perf_event_time(event
);
642 __perf_update_times(event
, now
, &event
->total_time_enabled
,
643 &event
->total_time_running
);
647 static void perf_event_update_sibling_time(struct perf_event
*leader
)
649 struct perf_event
*sibling
;
651 list_for_each_entry(sibling
, &leader
->sibling_list
, group_entry
)
652 perf_event_update_time(sibling
);
656 perf_event_set_state(struct perf_event
*event
, enum perf_event_state state
)
658 if (event
->state
== state
)
661 perf_event_update_time(event
);
663 * If a group leader gets enabled/disabled all its siblings
666 if ((event
->state
< 0) ^ (state
< 0))
667 perf_event_update_sibling_time(event
);
669 WRITE_ONCE(event
->state
, state
);
672 #ifdef CONFIG_CGROUP_PERF
675 perf_cgroup_match(struct perf_event
*event
)
677 struct perf_event_context
*ctx
= event
->ctx
;
678 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
680 /* @event doesn't care about cgroup */
684 /* wants specific cgroup scope but @cpuctx isn't associated with any */
689 * Cgroup scoping is recursive. An event enabled for a cgroup is
690 * also enabled for all its descendant cgroups. If @cpuctx's
691 * cgroup is a descendant of @event's (the test covers identity
692 * case), it's a match.
694 return cgroup_is_descendant(cpuctx
->cgrp
->css
.cgroup
,
695 event
->cgrp
->css
.cgroup
);
698 static inline void perf_detach_cgroup(struct perf_event
*event
)
700 css_put(&event
->cgrp
->css
);
704 static inline int is_cgroup_event(struct perf_event
*event
)
706 return event
->cgrp
!= NULL
;
709 static inline u64
perf_cgroup_event_time(struct perf_event
*event
)
711 struct perf_cgroup_info
*t
;
713 t
= per_cpu_ptr(event
->cgrp
->info
, event
->cpu
);
717 static inline void __update_cgrp_time(struct perf_cgroup
*cgrp
)
719 struct perf_cgroup_info
*info
;
724 info
= this_cpu_ptr(cgrp
->info
);
726 info
->time
+= now
- info
->timestamp
;
727 info
->timestamp
= now
;
730 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context
*cpuctx
)
732 struct perf_cgroup
*cgrp
= cpuctx
->cgrp
;
733 struct cgroup_subsys_state
*css
;
736 for (css
= &cgrp
->css
; css
; css
= css
->parent
) {
737 cgrp
= container_of(css
, struct perf_cgroup
, css
);
738 __update_cgrp_time(cgrp
);
743 static inline void update_cgrp_time_from_event(struct perf_event
*event
)
745 struct perf_cgroup
*cgrp
;
748 * ensure we access cgroup data only when needed and
749 * when we know the cgroup is pinned (css_get)
751 if (!is_cgroup_event(event
))
754 cgrp
= perf_cgroup_from_task(current
, event
->ctx
);
756 * Do not update time when cgroup is not active
758 if (cgroup_is_descendant(cgrp
->css
.cgroup
, event
->cgrp
->css
.cgroup
))
759 __update_cgrp_time(event
->cgrp
);
763 perf_cgroup_set_timestamp(struct task_struct
*task
,
764 struct perf_event_context
*ctx
)
766 struct perf_cgroup
*cgrp
;
767 struct perf_cgroup_info
*info
;
768 struct cgroup_subsys_state
*css
;
771 * ctx->lock held by caller
772 * ensure we do not access cgroup data
773 * unless we have the cgroup pinned (css_get)
775 if (!task
|| !ctx
->nr_cgroups
)
778 cgrp
= perf_cgroup_from_task(task
, ctx
);
780 for (css
= &cgrp
->css
; css
; css
= css
->parent
) {
781 cgrp
= container_of(css
, struct perf_cgroup
, css
);
782 info
= this_cpu_ptr(cgrp
->info
);
783 info
->timestamp
= ctx
->timestamp
;
787 static DEFINE_PER_CPU(struct list_head
, cgrp_cpuctx_list
);
789 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
790 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
793 * reschedule events based on the cgroup constraint of task.
795 * mode SWOUT : schedule out everything
796 * mode SWIN : schedule in based on cgroup for next
798 static void perf_cgroup_switch(struct task_struct
*task
, int mode
)
800 struct perf_cpu_context
*cpuctx
;
801 struct list_head
*list
;
805 * Disable interrupts and preemption to avoid this CPU's
806 * cgrp_cpuctx_entry to change under us.
808 local_irq_save(flags
);
810 list
= this_cpu_ptr(&cgrp_cpuctx_list
);
811 list_for_each_entry(cpuctx
, list
, cgrp_cpuctx_entry
) {
812 WARN_ON_ONCE(cpuctx
->ctx
.nr_cgroups
== 0);
814 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
815 perf_pmu_disable(cpuctx
->ctx
.pmu
);
817 if (mode
& PERF_CGROUP_SWOUT
) {
818 cpu_ctx_sched_out(cpuctx
, EVENT_ALL
);
820 * must not be done before ctxswout due
821 * to event_filter_match() in event_sched_out()
826 if (mode
& PERF_CGROUP_SWIN
) {
827 WARN_ON_ONCE(cpuctx
->cgrp
);
829 * set cgrp before ctxsw in to allow
830 * event_filter_match() to not have to pass
832 * we pass the cpuctx->ctx to perf_cgroup_from_task()
833 * because cgorup events are only per-cpu
835 cpuctx
->cgrp
= perf_cgroup_from_task(task
,
837 cpu_ctx_sched_in(cpuctx
, EVENT_ALL
, task
);
839 perf_pmu_enable(cpuctx
->ctx
.pmu
);
840 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
843 local_irq_restore(flags
);
846 static inline void perf_cgroup_sched_out(struct task_struct
*task
,
847 struct task_struct
*next
)
849 struct perf_cgroup
*cgrp1
;
850 struct perf_cgroup
*cgrp2
= NULL
;
854 * we come here when we know perf_cgroup_events > 0
855 * we do not need to pass the ctx here because we know
856 * we are holding the rcu lock
858 cgrp1
= perf_cgroup_from_task(task
, NULL
);
859 cgrp2
= perf_cgroup_from_task(next
, NULL
);
862 * only schedule out current cgroup events if we know
863 * that we are switching to a different cgroup. Otherwise,
864 * do no touch the cgroup events.
867 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
);
872 static inline void perf_cgroup_sched_in(struct task_struct
*prev
,
873 struct task_struct
*task
)
875 struct perf_cgroup
*cgrp1
;
876 struct perf_cgroup
*cgrp2
= NULL
;
880 * we come here when we know perf_cgroup_events > 0
881 * we do not need to pass the ctx here because we know
882 * we are holding the rcu lock
884 cgrp1
= perf_cgroup_from_task(task
, NULL
);
885 cgrp2
= perf_cgroup_from_task(prev
, NULL
);
888 * only need to schedule in cgroup events if we are changing
889 * cgroup during ctxsw. Cgroup events were not scheduled
890 * out of ctxsw out if that was not the case.
893 perf_cgroup_switch(task
, PERF_CGROUP_SWIN
);
898 static inline int perf_cgroup_connect(int fd
, struct perf_event
*event
,
899 struct perf_event_attr
*attr
,
900 struct perf_event
*group_leader
)
902 struct perf_cgroup
*cgrp
;
903 struct cgroup_subsys_state
*css
;
904 struct fd f
= fdget(fd
);
910 css
= css_tryget_online_from_dir(f
.file
->f_path
.dentry
,
911 &perf_event_cgrp_subsys
);
917 cgrp
= container_of(css
, struct perf_cgroup
, css
);
921 * all events in a group must monitor
922 * the same cgroup because a task belongs
923 * to only one perf cgroup at a time
925 if (group_leader
&& group_leader
->cgrp
!= cgrp
) {
926 perf_detach_cgroup(event
);
935 perf_cgroup_set_shadow_time(struct perf_event
*event
, u64 now
)
937 struct perf_cgroup_info
*t
;
938 t
= per_cpu_ptr(event
->cgrp
->info
, event
->cpu
);
939 event
->shadow_ctx_time
= now
- t
->timestamp
;
943 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
944 * cleared when last cgroup event is removed.
947 list_update_cgroup_event(struct perf_event
*event
,
948 struct perf_event_context
*ctx
, bool add
)
950 struct perf_cpu_context
*cpuctx
;
951 struct list_head
*cpuctx_entry
;
953 if (!is_cgroup_event(event
))
957 * Because cgroup events are always per-cpu events,
958 * this will always be called from the right CPU.
960 cpuctx
= __get_cpu_context(ctx
);
963 * Since setting cpuctx->cgrp is conditional on the current @cgrp
964 * matching the event's cgroup, we must do this for every new event,
965 * because if the first would mismatch, the second would not try again
966 * and we would leave cpuctx->cgrp unset.
968 if (add
&& !cpuctx
->cgrp
) {
969 struct perf_cgroup
*cgrp
= perf_cgroup_from_task(current
, ctx
);
971 if (cgroup_is_descendant(cgrp
->css
.cgroup
, event
->cgrp
->css
.cgroup
))
975 if (add
&& ctx
->nr_cgroups
++)
977 else if (!add
&& --ctx
->nr_cgroups
)
980 /* no cgroup running */
984 cpuctx_entry
= &cpuctx
->cgrp_cpuctx_entry
;
986 list_add(cpuctx_entry
, this_cpu_ptr(&cgrp_cpuctx_list
));
988 list_del(cpuctx_entry
);
991 #else /* !CONFIG_CGROUP_PERF */
994 perf_cgroup_match(struct perf_event
*event
)
999 static inline void perf_detach_cgroup(struct perf_event
*event
)
1002 static inline int is_cgroup_event(struct perf_event
*event
)
1007 static inline void update_cgrp_time_from_event(struct perf_event
*event
)
1011 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context
*cpuctx
)
1015 static inline void perf_cgroup_sched_out(struct task_struct
*task
,
1016 struct task_struct
*next
)
1020 static inline void perf_cgroup_sched_in(struct task_struct
*prev
,
1021 struct task_struct
*task
)
1025 static inline int perf_cgroup_connect(pid_t pid
, struct perf_event
*event
,
1026 struct perf_event_attr
*attr
,
1027 struct perf_event
*group_leader
)
1033 perf_cgroup_set_timestamp(struct task_struct
*task
,
1034 struct perf_event_context
*ctx
)
1039 perf_cgroup_switch(struct task_struct
*task
, struct task_struct
*next
)
1044 perf_cgroup_set_shadow_time(struct perf_event
*event
, u64 now
)
1048 static inline u64
perf_cgroup_event_time(struct perf_event
*event
)
1054 list_update_cgroup_event(struct perf_event
*event
,
1055 struct perf_event_context
*ctx
, bool add
)
1062 * set default to be dependent on timer tick just
1063 * like original code
1065 #define PERF_CPU_HRTIMER (1000 / HZ)
1067 * function must be called with interrupts disabled
1069 static enum hrtimer_restart
perf_mux_hrtimer_handler(struct hrtimer
*hr
)
1071 struct perf_cpu_context
*cpuctx
;
1074 lockdep_assert_irqs_disabled();
1076 cpuctx
= container_of(hr
, struct perf_cpu_context
, hrtimer
);
1077 rotations
= perf_rotate_context(cpuctx
);
1079 raw_spin_lock(&cpuctx
->hrtimer_lock
);
1081 hrtimer_forward_now(hr
, cpuctx
->hrtimer_interval
);
1083 cpuctx
->hrtimer_active
= 0;
1084 raw_spin_unlock(&cpuctx
->hrtimer_lock
);
1086 return rotations
? HRTIMER_RESTART
: HRTIMER_NORESTART
;
1089 static void __perf_mux_hrtimer_init(struct perf_cpu_context
*cpuctx
, int cpu
)
1091 struct hrtimer
*timer
= &cpuctx
->hrtimer
;
1092 struct pmu
*pmu
= cpuctx
->ctx
.pmu
;
1095 /* no multiplexing needed for SW PMU */
1096 if (pmu
->task_ctx_nr
== perf_sw_context
)
1100 * check default is sane, if not set then force to
1101 * default interval (1/tick)
1103 interval
= pmu
->hrtimer_interval_ms
;
1105 interval
= pmu
->hrtimer_interval_ms
= PERF_CPU_HRTIMER
;
1107 cpuctx
->hrtimer_interval
= ns_to_ktime(NSEC_PER_MSEC
* interval
);
1109 raw_spin_lock_init(&cpuctx
->hrtimer_lock
);
1110 hrtimer_init(timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_ABS_PINNED
);
1111 timer
->function
= perf_mux_hrtimer_handler
;
1114 static int perf_mux_hrtimer_restart(struct perf_cpu_context
*cpuctx
)
1116 struct hrtimer
*timer
= &cpuctx
->hrtimer
;
1117 struct pmu
*pmu
= cpuctx
->ctx
.pmu
;
1118 unsigned long flags
;
1120 /* not for SW PMU */
1121 if (pmu
->task_ctx_nr
== perf_sw_context
)
1124 raw_spin_lock_irqsave(&cpuctx
->hrtimer_lock
, flags
);
1125 if (!cpuctx
->hrtimer_active
) {
1126 cpuctx
->hrtimer_active
= 1;
1127 hrtimer_forward_now(timer
, cpuctx
->hrtimer_interval
);
1128 hrtimer_start_expires(timer
, HRTIMER_MODE_ABS_PINNED
);
1130 raw_spin_unlock_irqrestore(&cpuctx
->hrtimer_lock
, flags
);
1135 void perf_pmu_disable(struct pmu
*pmu
)
1137 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
1139 pmu
->pmu_disable(pmu
);
1142 void perf_pmu_enable(struct pmu
*pmu
)
1144 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
1146 pmu
->pmu_enable(pmu
);
1149 static DEFINE_PER_CPU(struct list_head
, active_ctx_list
);
1152 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1153 * perf_event_task_tick() are fully serialized because they're strictly cpu
1154 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1155 * disabled, while perf_event_task_tick is called from IRQ context.
1157 static void perf_event_ctx_activate(struct perf_event_context
*ctx
)
1159 struct list_head
*head
= this_cpu_ptr(&active_ctx_list
);
1161 lockdep_assert_irqs_disabled();
1163 WARN_ON(!list_empty(&ctx
->active_ctx_list
));
1165 list_add(&ctx
->active_ctx_list
, head
);
1168 static void perf_event_ctx_deactivate(struct perf_event_context
*ctx
)
1170 lockdep_assert_irqs_disabled();
1172 WARN_ON(list_empty(&ctx
->active_ctx_list
));
1174 list_del_init(&ctx
->active_ctx_list
);
1177 static void get_ctx(struct perf_event_context
*ctx
)
1179 WARN_ON(!atomic_inc_not_zero(&ctx
->refcount
));
1182 static void free_ctx(struct rcu_head
*head
)
1184 struct perf_event_context
*ctx
;
1186 ctx
= container_of(head
, struct perf_event_context
, rcu_head
);
1187 kfree(ctx
->task_ctx_data
);
1191 static void put_ctx(struct perf_event_context
*ctx
)
1193 if (atomic_dec_and_test(&ctx
->refcount
)) {
1194 if (ctx
->parent_ctx
)
1195 put_ctx(ctx
->parent_ctx
);
1196 if (ctx
->task
&& ctx
->task
!= TASK_TOMBSTONE
)
1197 put_task_struct(ctx
->task
);
1198 call_rcu(&ctx
->rcu_head
, free_ctx
);
1203 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1204 * perf_pmu_migrate_context() we need some magic.
1206 * Those places that change perf_event::ctx will hold both
1207 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1209 * Lock ordering is by mutex address. There are two other sites where
1210 * perf_event_context::mutex nests and those are:
1212 * - perf_event_exit_task_context() [ child , 0 ]
1213 * perf_event_exit_event()
1214 * put_event() [ parent, 1 ]
1216 * - perf_event_init_context() [ parent, 0 ]
1217 * inherit_task_group()
1220 * perf_event_alloc()
1222 * perf_try_init_event() [ child , 1 ]
1224 * While it appears there is an obvious deadlock here -- the parent and child
1225 * nesting levels are inverted between the two. This is in fact safe because
1226 * life-time rules separate them. That is an exiting task cannot fork, and a
1227 * spawning task cannot (yet) exit.
1229 * But remember that that these are parent<->child context relations, and
1230 * migration does not affect children, therefore these two orderings should not
1233 * The change in perf_event::ctx does not affect children (as claimed above)
1234 * because the sys_perf_event_open() case will install a new event and break
1235 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1236 * concerned with cpuctx and that doesn't have children.
1238 * The places that change perf_event::ctx will issue:
1240 * perf_remove_from_context();
1241 * synchronize_rcu();
1242 * perf_install_in_context();
1244 * to affect the change. The remove_from_context() + synchronize_rcu() should
1245 * quiesce the event, after which we can install it in the new location. This
1246 * means that only external vectors (perf_fops, prctl) can perturb the event
1247 * while in transit. Therefore all such accessors should also acquire
1248 * perf_event_context::mutex to serialize against this.
1250 * However; because event->ctx can change while we're waiting to acquire
1251 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1256 * task_struct::perf_event_mutex
1257 * perf_event_context::mutex
1258 * perf_event::child_mutex;
1259 * perf_event_context::lock
1260 * perf_event::mmap_mutex
1265 * cpuctx->mutex / perf_event_context::mutex
1267 static struct perf_event_context
*
1268 perf_event_ctx_lock_nested(struct perf_event
*event
, int nesting
)
1270 struct perf_event_context
*ctx
;
1274 ctx
= READ_ONCE(event
->ctx
);
1275 if (!atomic_inc_not_zero(&ctx
->refcount
)) {
1281 mutex_lock_nested(&ctx
->mutex
, nesting
);
1282 if (event
->ctx
!= ctx
) {
1283 mutex_unlock(&ctx
->mutex
);
1291 static inline struct perf_event_context
*
1292 perf_event_ctx_lock(struct perf_event
*event
)
1294 return perf_event_ctx_lock_nested(event
, 0);
1297 static void perf_event_ctx_unlock(struct perf_event
*event
,
1298 struct perf_event_context
*ctx
)
1300 mutex_unlock(&ctx
->mutex
);
1305 * This must be done under the ctx->lock, such as to serialize against
1306 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1307 * calling scheduler related locks and ctx->lock nests inside those.
1309 static __must_check
struct perf_event_context
*
1310 unclone_ctx(struct perf_event_context
*ctx
)
1312 struct perf_event_context
*parent_ctx
= ctx
->parent_ctx
;
1314 lockdep_assert_held(&ctx
->lock
);
1317 ctx
->parent_ctx
= NULL
;
1323 static u32
perf_event_pid_type(struct perf_event
*event
, struct task_struct
*p
,
1328 * only top level events have the pid namespace they were created in
1331 event
= event
->parent
;
1333 nr
= __task_pid_nr_ns(p
, type
, event
->ns
);
1334 /* avoid -1 if it is idle thread or runs in another ns */
1335 if (!nr
&& !pid_alive(p
))
1340 static u32
perf_event_pid(struct perf_event
*event
, struct task_struct
*p
)
1342 return perf_event_pid_type(event
, p
, __PIDTYPE_TGID
);
1345 static u32
perf_event_tid(struct perf_event
*event
, struct task_struct
*p
)
1347 return perf_event_pid_type(event
, p
, PIDTYPE_PID
);
1351 * If we inherit events we want to return the parent event id
1354 static u64
primary_event_id(struct perf_event
*event
)
1359 id
= event
->parent
->id
;
1365 * Get the perf_event_context for a task and lock it.
1367 * This has to cope with with the fact that until it is locked,
1368 * the context could get moved to another task.
1370 static struct perf_event_context
*
1371 perf_lock_task_context(struct task_struct
*task
, int ctxn
, unsigned long *flags
)
1373 struct perf_event_context
*ctx
;
1377 * One of the few rules of preemptible RCU is that one cannot do
1378 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1379 * part of the read side critical section was irqs-enabled -- see
1380 * rcu_read_unlock_special().
1382 * Since ctx->lock nests under rq->lock we must ensure the entire read
1383 * side critical section has interrupts disabled.
1385 local_irq_save(*flags
);
1387 ctx
= rcu_dereference(task
->perf_event_ctxp
[ctxn
]);
1390 * If this context is a clone of another, it might
1391 * get swapped for another underneath us by
1392 * perf_event_task_sched_out, though the
1393 * rcu_read_lock() protects us from any context
1394 * getting freed. Lock the context and check if it
1395 * got swapped before we could get the lock, and retry
1396 * if so. If we locked the right context, then it
1397 * can't get swapped on us any more.
1399 raw_spin_lock(&ctx
->lock
);
1400 if (ctx
!= rcu_dereference(task
->perf_event_ctxp
[ctxn
])) {
1401 raw_spin_unlock(&ctx
->lock
);
1403 local_irq_restore(*flags
);
1407 if (ctx
->task
== TASK_TOMBSTONE
||
1408 !atomic_inc_not_zero(&ctx
->refcount
)) {
1409 raw_spin_unlock(&ctx
->lock
);
1412 WARN_ON_ONCE(ctx
->task
!= task
);
1417 local_irq_restore(*flags
);
1422 * Get the context for a task and increment its pin_count so it
1423 * can't get swapped to another task. This also increments its
1424 * reference count so that the context can't get freed.
1426 static struct perf_event_context
*
1427 perf_pin_task_context(struct task_struct
*task
, int ctxn
)
1429 struct perf_event_context
*ctx
;
1430 unsigned long flags
;
1432 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
1435 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1440 static void perf_unpin_context(struct perf_event_context
*ctx
)
1442 unsigned long flags
;
1444 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
1446 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1450 * Update the record of the current time in a context.
1452 static void update_context_time(struct perf_event_context
*ctx
)
1454 u64 now
= perf_clock();
1456 ctx
->time
+= now
- ctx
->timestamp
;
1457 ctx
->timestamp
= now
;
1460 static u64
perf_event_time(struct perf_event
*event
)
1462 struct perf_event_context
*ctx
= event
->ctx
;
1464 if (is_cgroup_event(event
))
1465 return perf_cgroup_event_time(event
);
1467 return ctx
? ctx
->time
: 0;
1470 static enum event_type_t
get_event_type(struct perf_event
*event
)
1472 struct perf_event_context
*ctx
= event
->ctx
;
1473 enum event_type_t event_type
;
1475 lockdep_assert_held(&ctx
->lock
);
1478 * It's 'group type', really, because if our group leader is
1479 * pinned, so are we.
1481 if (event
->group_leader
!= event
)
1482 event
= event
->group_leader
;
1484 event_type
= event
->attr
.pinned
? EVENT_PINNED
: EVENT_FLEXIBLE
;
1486 event_type
|= EVENT_CPU
;
1491 static struct list_head
*
1492 ctx_group_list(struct perf_event
*event
, struct perf_event_context
*ctx
)
1494 if (event
->attr
.pinned
)
1495 return &ctx
->pinned_groups
;
1497 return &ctx
->flexible_groups
;
1501 * Add a event from the lists for its context.
1502 * Must be called with ctx->mutex and ctx->lock held.
1505 list_add_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
1507 lockdep_assert_held(&ctx
->lock
);
1509 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_CONTEXT
);
1510 event
->attach_state
|= PERF_ATTACH_CONTEXT
;
1512 event
->tstamp
= perf_event_time(event
);
1515 * If we're a stand alone event or group leader, we go to the context
1516 * list, group events are kept attached to the group so that
1517 * perf_group_detach can, at all times, locate all siblings.
1519 if (event
->group_leader
== event
) {
1520 struct list_head
*list
;
1522 event
->group_caps
= event
->event_caps
;
1524 list
= ctx_group_list(event
, ctx
);
1525 list_add_tail(&event
->group_entry
, list
);
1528 list_update_cgroup_event(event
, ctx
, true);
1530 list_add_rcu(&event
->event_entry
, &ctx
->event_list
);
1532 if (event
->attr
.inherit_stat
)
1539 * Initialize event state based on the perf_event_attr::disabled.
1541 static inline void perf_event__state_init(struct perf_event
*event
)
1543 event
->state
= event
->attr
.disabled
? PERF_EVENT_STATE_OFF
:
1544 PERF_EVENT_STATE_INACTIVE
;
1547 static void __perf_event_read_size(struct perf_event
*event
, int nr_siblings
)
1549 int entry
= sizeof(u64
); /* value */
1553 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1554 size
+= sizeof(u64
);
1556 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1557 size
+= sizeof(u64
);
1559 if (event
->attr
.read_format
& PERF_FORMAT_ID
)
1560 entry
+= sizeof(u64
);
1562 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
) {
1564 size
+= sizeof(u64
);
1568 event
->read_size
= size
;
1571 static void __perf_event_header_size(struct perf_event
*event
, u64 sample_type
)
1573 struct perf_sample_data
*data
;
1576 if (sample_type
& PERF_SAMPLE_IP
)
1577 size
+= sizeof(data
->ip
);
1579 if (sample_type
& PERF_SAMPLE_ADDR
)
1580 size
+= sizeof(data
->addr
);
1582 if (sample_type
& PERF_SAMPLE_PERIOD
)
1583 size
+= sizeof(data
->period
);
1585 if (sample_type
& PERF_SAMPLE_WEIGHT
)
1586 size
+= sizeof(data
->weight
);
1588 if (sample_type
& PERF_SAMPLE_READ
)
1589 size
+= event
->read_size
;
1591 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
1592 size
+= sizeof(data
->data_src
.val
);
1594 if (sample_type
& PERF_SAMPLE_TRANSACTION
)
1595 size
+= sizeof(data
->txn
);
1597 if (sample_type
& PERF_SAMPLE_PHYS_ADDR
)
1598 size
+= sizeof(data
->phys_addr
);
1600 event
->header_size
= size
;
1604 * Called at perf_event creation and when events are attached/detached from a
1607 static void perf_event__header_size(struct perf_event
*event
)
1609 __perf_event_read_size(event
,
1610 event
->group_leader
->nr_siblings
);
1611 __perf_event_header_size(event
, event
->attr
.sample_type
);
1614 static void perf_event__id_header_size(struct perf_event
*event
)
1616 struct perf_sample_data
*data
;
1617 u64 sample_type
= event
->attr
.sample_type
;
1620 if (sample_type
& PERF_SAMPLE_TID
)
1621 size
+= sizeof(data
->tid_entry
);
1623 if (sample_type
& PERF_SAMPLE_TIME
)
1624 size
+= sizeof(data
->time
);
1626 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
1627 size
+= sizeof(data
->id
);
1629 if (sample_type
& PERF_SAMPLE_ID
)
1630 size
+= sizeof(data
->id
);
1632 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
1633 size
+= sizeof(data
->stream_id
);
1635 if (sample_type
& PERF_SAMPLE_CPU
)
1636 size
+= sizeof(data
->cpu_entry
);
1638 event
->id_header_size
= size
;
1641 static bool perf_event_validate_size(struct perf_event
*event
)
1644 * The values computed here will be over-written when we actually
1647 __perf_event_read_size(event
, event
->group_leader
->nr_siblings
+ 1);
1648 __perf_event_header_size(event
, event
->attr
.sample_type
& ~PERF_SAMPLE_READ
);
1649 perf_event__id_header_size(event
);
1652 * Sum the lot; should not exceed the 64k limit we have on records.
1653 * Conservative limit to allow for callchains and other variable fields.
1655 if (event
->read_size
+ event
->header_size
+
1656 event
->id_header_size
+ sizeof(struct perf_event_header
) >= 16*1024)
1662 static void perf_group_attach(struct perf_event
*event
)
1664 struct perf_event
*group_leader
= event
->group_leader
, *pos
;
1666 lockdep_assert_held(&event
->ctx
->lock
);
1669 * We can have double attach due to group movement in perf_event_open.
1671 if (event
->attach_state
& PERF_ATTACH_GROUP
)
1674 event
->attach_state
|= PERF_ATTACH_GROUP
;
1676 if (group_leader
== event
)
1679 WARN_ON_ONCE(group_leader
->ctx
!= event
->ctx
);
1681 group_leader
->group_caps
&= event
->event_caps
;
1683 list_add_tail(&event
->group_entry
, &group_leader
->sibling_list
);
1684 group_leader
->nr_siblings
++;
1686 perf_event__header_size(group_leader
);
1688 list_for_each_entry(pos
, &group_leader
->sibling_list
, group_entry
)
1689 perf_event__header_size(pos
);
1693 * Remove a event from the lists for its context.
1694 * Must be called with ctx->mutex and ctx->lock held.
1697 list_del_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
1699 WARN_ON_ONCE(event
->ctx
!= ctx
);
1700 lockdep_assert_held(&ctx
->lock
);
1703 * We can have double detach due to exit/hot-unplug + close.
1705 if (!(event
->attach_state
& PERF_ATTACH_CONTEXT
))
1708 event
->attach_state
&= ~PERF_ATTACH_CONTEXT
;
1710 list_update_cgroup_event(event
, ctx
, false);
1713 if (event
->attr
.inherit_stat
)
1716 list_del_rcu(&event
->event_entry
);
1718 if (event
->group_leader
== event
)
1719 list_del_init(&event
->group_entry
);
1722 * If event was in error state, then keep it
1723 * that way, otherwise bogus counts will be
1724 * returned on read(). The only way to get out
1725 * of error state is by explicit re-enabling
1728 if (event
->state
> PERF_EVENT_STATE_OFF
)
1729 perf_event_set_state(event
, PERF_EVENT_STATE_OFF
);
1734 static void perf_group_detach(struct perf_event
*event
)
1736 struct perf_event
*sibling
, *tmp
;
1737 struct list_head
*list
= NULL
;
1739 lockdep_assert_held(&event
->ctx
->lock
);
1742 * We can have double detach due to exit/hot-unplug + close.
1744 if (!(event
->attach_state
& PERF_ATTACH_GROUP
))
1747 event
->attach_state
&= ~PERF_ATTACH_GROUP
;
1750 * If this is a sibling, remove it from its group.
1752 if (event
->group_leader
!= event
) {
1753 list_del_init(&event
->group_entry
);
1754 event
->group_leader
->nr_siblings
--;
1758 if (!list_empty(&event
->group_entry
))
1759 list
= &event
->group_entry
;
1762 * If this was a group event with sibling events then
1763 * upgrade the siblings to singleton events by adding them
1764 * to whatever list we are on.
1766 list_for_each_entry_safe(sibling
, tmp
, &event
->sibling_list
, group_entry
) {
1768 list_move_tail(&sibling
->group_entry
, list
);
1769 sibling
->group_leader
= sibling
;
1771 /* Inherit group flags from the previous leader */
1772 sibling
->group_caps
= event
->group_caps
;
1774 WARN_ON_ONCE(sibling
->ctx
!= event
->ctx
);
1778 perf_event__header_size(event
->group_leader
);
1780 list_for_each_entry(tmp
, &event
->group_leader
->sibling_list
, group_entry
)
1781 perf_event__header_size(tmp
);
1784 static bool is_orphaned_event(struct perf_event
*event
)
1786 return event
->state
== PERF_EVENT_STATE_DEAD
;
1789 static inline int __pmu_filter_match(struct perf_event
*event
)
1791 struct pmu
*pmu
= event
->pmu
;
1792 return pmu
->filter_match
? pmu
->filter_match(event
) : 1;
1796 * Check whether we should attempt to schedule an event group based on
1797 * PMU-specific filtering. An event group can consist of HW and SW events,
1798 * potentially with a SW leader, so we must check all the filters, to
1799 * determine whether a group is schedulable:
1801 static inline int pmu_filter_match(struct perf_event
*event
)
1803 struct perf_event
*child
;
1805 if (!__pmu_filter_match(event
))
1808 list_for_each_entry(child
, &event
->sibling_list
, group_entry
) {
1809 if (!__pmu_filter_match(child
))
1817 event_filter_match(struct perf_event
*event
)
1819 return (event
->cpu
== -1 || event
->cpu
== smp_processor_id()) &&
1820 perf_cgroup_match(event
) && pmu_filter_match(event
);
1824 event_sched_out(struct perf_event
*event
,
1825 struct perf_cpu_context
*cpuctx
,
1826 struct perf_event_context
*ctx
)
1828 enum perf_event_state state
= PERF_EVENT_STATE_INACTIVE
;
1830 WARN_ON_ONCE(event
->ctx
!= ctx
);
1831 lockdep_assert_held(&ctx
->lock
);
1833 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
1836 perf_pmu_disable(event
->pmu
);
1838 event
->pmu
->del(event
, 0);
1841 if (READ_ONCE(event
->pending_disable
) >= 0) {
1842 WRITE_ONCE(event
->pending_disable
, -1);
1843 state
= PERF_EVENT_STATE_OFF
;
1845 perf_event_set_state(event
, state
);
1847 if (!is_software_event(event
))
1848 cpuctx
->active_oncpu
--;
1849 if (!--ctx
->nr_active
)
1850 perf_event_ctx_deactivate(ctx
);
1851 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
1853 if (event
->attr
.exclusive
|| !cpuctx
->active_oncpu
)
1854 cpuctx
->exclusive
= 0;
1856 perf_pmu_enable(event
->pmu
);
1860 group_sched_out(struct perf_event
*group_event
,
1861 struct perf_cpu_context
*cpuctx
,
1862 struct perf_event_context
*ctx
)
1864 struct perf_event
*event
;
1866 if (group_event
->state
!= PERF_EVENT_STATE_ACTIVE
)
1869 perf_pmu_disable(ctx
->pmu
);
1871 event_sched_out(group_event
, cpuctx
, ctx
);
1874 * Schedule out siblings (if any):
1876 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
)
1877 event_sched_out(event
, cpuctx
, ctx
);
1879 perf_pmu_enable(ctx
->pmu
);
1881 if (group_event
->attr
.exclusive
)
1882 cpuctx
->exclusive
= 0;
1885 #define DETACH_GROUP 0x01UL
1888 * Cross CPU call to remove a performance event
1890 * We disable the event on the hardware level first. After that we
1891 * remove it from the context list.
1894 __perf_remove_from_context(struct perf_event
*event
,
1895 struct perf_cpu_context
*cpuctx
,
1896 struct perf_event_context
*ctx
,
1899 unsigned long flags
= (unsigned long)info
;
1901 if (ctx
->is_active
& EVENT_TIME
) {
1902 update_context_time(ctx
);
1903 update_cgrp_time_from_cpuctx(cpuctx
);
1906 event_sched_out(event
, cpuctx
, ctx
);
1907 if (flags
& DETACH_GROUP
)
1908 perf_group_detach(event
);
1909 list_del_event(event
, ctx
);
1911 if (!ctx
->nr_events
&& ctx
->is_active
) {
1914 WARN_ON_ONCE(cpuctx
->task_ctx
!= ctx
);
1915 cpuctx
->task_ctx
= NULL
;
1921 * Remove the event from a task's (or a CPU's) list of events.
1923 * If event->ctx is a cloned context, callers must make sure that
1924 * every task struct that event->ctx->task could possibly point to
1925 * remains valid. This is OK when called from perf_release since
1926 * that only calls us on the top-level context, which can't be a clone.
1927 * When called from perf_event_exit_task, it's OK because the
1928 * context has been detached from its task.
1930 static void perf_remove_from_context(struct perf_event
*event
, unsigned long flags
)
1932 struct perf_event_context
*ctx
= event
->ctx
;
1934 lockdep_assert_held(&ctx
->mutex
);
1936 event_function_call(event
, __perf_remove_from_context
, (void *)flags
);
1939 * The above event_function_call() can NO-OP when it hits
1940 * TASK_TOMBSTONE. In that case we must already have been detached
1941 * from the context (by perf_event_exit_event()) but the grouping
1942 * might still be in-tact.
1944 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_CONTEXT
);
1945 if ((flags
& DETACH_GROUP
) &&
1946 (event
->attach_state
& PERF_ATTACH_GROUP
)) {
1948 * Since in that case we cannot possibly be scheduled, simply
1951 raw_spin_lock_irq(&ctx
->lock
);
1952 perf_group_detach(event
);
1953 raw_spin_unlock_irq(&ctx
->lock
);
1958 * Cross CPU call to disable a performance event
1960 static void __perf_event_disable(struct perf_event
*event
,
1961 struct perf_cpu_context
*cpuctx
,
1962 struct perf_event_context
*ctx
,
1965 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
1968 if (ctx
->is_active
& EVENT_TIME
) {
1969 update_context_time(ctx
);
1970 update_cgrp_time_from_event(event
);
1973 if (event
== event
->group_leader
)
1974 group_sched_out(event
, cpuctx
, ctx
);
1976 event_sched_out(event
, cpuctx
, ctx
);
1978 perf_event_set_state(event
, PERF_EVENT_STATE_OFF
);
1984 * If event->ctx is a cloned context, callers must make sure that
1985 * every task struct that event->ctx->task could possibly point to
1986 * remains valid. This condition is satisifed when called through
1987 * perf_event_for_each_child or perf_event_for_each because they
1988 * hold the top-level event's child_mutex, so any descendant that
1989 * goes to exit will block in perf_event_exit_event().
1991 * When called from perf_pending_event it's OK because event->ctx
1992 * is the current context on this CPU and preemption is disabled,
1993 * hence we can't get into perf_event_task_sched_out for this context.
1995 static void _perf_event_disable(struct perf_event
*event
)
1997 struct perf_event_context
*ctx
= event
->ctx
;
1999 raw_spin_lock_irq(&ctx
->lock
);
2000 if (event
->state
<= PERF_EVENT_STATE_OFF
) {
2001 raw_spin_unlock_irq(&ctx
->lock
);
2004 raw_spin_unlock_irq(&ctx
->lock
);
2006 event_function_call(event
, __perf_event_disable
, NULL
);
2009 void perf_event_disable_local(struct perf_event
*event
)
2011 event_function_local(event
, __perf_event_disable
, NULL
);
2015 * Strictly speaking kernel users cannot create groups and therefore this
2016 * interface does not need the perf_event_ctx_lock() magic.
2018 void perf_event_disable(struct perf_event
*event
)
2020 struct perf_event_context
*ctx
;
2022 ctx
= perf_event_ctx_lock(event
);
2023 _perf_event_disable(event
);
2024 perf_event_ctx_unlock(event
, ctx
);
2026 EXPORT_SYMBOL_GPL(perf_event_disable
);
2028 void perf_event_disable_inatomic(struct perf_event
*event
)
2030 WRITE_ONCE(event
->pending_disable
, smp_processor_id());
2031 /* can fail, see perf_pending_event_disable() */
2032 irq_work_queue(&event
->pending
);
2035 static void perf_set_shadow_time(struct perf_event
*event
,
2036 struct perf_event_context
*ctx
)
2039 * use the correct time source for the time snapshot
2041 * We could get by without this by leveraging the
2042 * fact that to get to this function, the caller
2043 * has most likely already called update_context_time()
2044 * and update_cgrp_time_xx() and thus both timestamp
2045 * are identical (or very close). Given that tstamp is,
2046 * already adjusted for cgroup, we could say that:
2047 * tstamp - ctx->timestamp
2049 * tstamp - cgrp->timestamp.
2051 * Then, in perf_output_read(), the calculation would
2052 * work with no changes because:
2053 * - event is guaranteed scheduled in
2054 * - no scheduled out in between
2055 * - thus the timestamp would be the same
2057 * But this is a bit hairy.
2059 * So instead, we have an explicit cgroup call to remain
2060 * within the time time source all along. We believe it
2061 * is cleaner and simpler to understand.
2063 if (is_cgroup_event(event
))
2064 perf_cgroup_set_shadow_time(event
, event
->tstamp
);
2066 event
->shadow_ctx_time
= event
->tstamp
- ctx
->timestamp
;
2069 #define MAX_INTERRUPTS (~0ULL)
2071 static void perf_log_throttle(struct perf_event
*event
, int enable
);
2072 static void perf_log_itrace_start(struct perf_event
*event
);
2075 event_sched_in(struct perf_event
*event
,
2076 struct perf_cpu_context
*cpuctx
,
2077 struct perf_event_context
*ctx
)
2081 lockdep_assert_held(&ctx
->lock
);
2083 if (event
->state
<= PERF_EVENT_STATE_OFF
)
2086 WRITE_ONCE(event
->oncpu
, smp_processor_id());
2088 * Order event::oncpu write to happen before the ACTIVE state is
2089 * visible. This allows perf_event_{stop,read}() to observe the correct
2090 * ->oncpu if it sees ACTIVE.
2093 perf_event_set_state(event
, PERF_EVENT_STATE_ACTIVE
);
2096 * Unthrottle events, since we scheduled we might have missed several
2097 * ticks already, also for a heavily scheduling task there is little
2098 * guarantee it'll get a tick in a timely manner.
2100 if (unlikely(event
->hw
.interrupts
== MAX_INTERRUPTS
)) {
2101 perf_log_throttle(event
, 1);
2102 event
->hw
.interrupts
= 0;
2105 perf_pmu_disable(event
->pmu
);
2107 perf_set_shadow_time(event
, ctx
);
2109 perf_log_itrace_start(event
);
2111 if (event
->pmu
->add(event
, PERF_EF_START
)) {
2112 perf_event_set_state(event
, PERF_EVENT_STATE_INACTIVE
);
2118 if (!is_software_event(event
))
2119 cpuctx
->active_oncpu
++;
2120 if (!ctx
->nr_active
++)
2121 perf_event_ctx_activate(ctx
);
2122 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
2125 if (event
->attr
.exclusive
)
2126 cpuctx
->exclusive
= 1;
2129 perf_pmu_enable(event
->pmu
);
2135 group_sched_in(struct perf_event
*group_event
,
2136 struct perf_cpu_context
*cpuctx
,
2137 struct perf_event_context
*ctx
)
2139 struct perf_event
*event
, *partial_group
= NULL
;
2140 struct pmu
*pmu
= ctx
->pmu
;
2142 if (group_event
->state
== PERF_EVENT_STATE_OFF
)
2145 pmu
->start_txn(pmu
, PERF_PMU_TXN_ADD
);
2147 if (event_sched_in(group_event
, cpuctx
, ctx
)) {
2148 pmu
->cancel_txn(pmu
);
2149 perf_mux_hrtimer_restart(cpuctx
);
2154 * Schedule in siblings as one group (if any):
2156 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
2157 if (event_sched_in(event
, cpuctx
, ctx
)) {
2158 partial_group
= event
;
2163 if (!pmu
->commit_txn(pmu
))
2168 * Groups can be scheduled in as one unit only, so undo any
2169 * partial group before returning:
2170 * The events up to the failed event are scheduled out normally.
2172 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
2173 if (event
== partial_group
)
2176 event_sched_out(event
, cpuctx
, ctx
);
2178 event_sched_out(group_event
, cpuctx
, ctx
);
2180 pmu
->cancel_txn(pmu
);
2182 perf_mux_hrtimer_restart(cpuctx
);
2188 * Work out whether we can put this event group on the CPU now.
2190 static int group_can_go_on(struct perf_event
*event
,
2191 struct perf_cpu_context
*cpuctx
,
2195 * Groups consisting entirely of software events can always go on.
2197 if (event
->group_caps
& PERF_EV_CAP_SOFTWARE
)
2200 * If an exclusive group is already on, no other hardware
2203 if (cpuctx
->exclusive
)
2206 * If this group is exclusive and there are already
2207 * events on the CPU, it can't go on.
2209 if (event
->attr
.exclusive
&& cpuctx
->active_oncpu
)
2212 * Otherwise, try to add it if all previous groups were able
2218 static void add_event_to_ctx(struct perf_event
*event
,
2219 struct perf_event_context
*ctx
)
2221 list_add_event(event
, ctx
);
2222 perf_group_attach(event
);
2225 static void ctx_sched_out(struct perf_event_context
*ctx
,
2226 struct perf_cpu_context
*cpuctx
,
2227 enum event_type_t event_type
);
2229 ctx_sched_in(struct perf_event_context
*ctx
,
2230 struct perf_cpu_context
*cpuctx
,
2231 enum event_type_t event_type
,
2232 struct task_struct
*task
);
2234 static void task_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
2235 struct perf_event_context
*ctx
,
2236 enum event_type_t event_type
)
2238 if (!cpuctx
->task_ctx
)
2241 if (WARN_ON_ONCE(ctx
!= cpuctx
->task_ctx
))
2244 ctx_sched_out(ctx
, cpuctx
, event_type
);
2247 static void perf_event_sched_in(struct perf_cpu_context
*cpuctx
,
2248 struct perf_event_context
*ctx
,
2249 struct task_struct
*task
)
2251 cpu_ctx_sched_in(cpuctx
, EVENT_PINNED
, task
);
2253 ctx_sched_in(ctx
, cpuctx
, EVENT_PINNED
, task
);
2254 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
, task
);
2256 ctx_sched_in(ctx
, cpuctx
, EVENT_FLEXIBLE
, task
);
2260 * We want to maintain the following priority of scheduling:
2261 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2262 * - task pinned (EVENT_PINNED)
2263 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2264 * - task flexible (EVENT_FLEXIBLE).
2266 * In order to avoid unscheduling and scheduling back in everything every
2267 * time an event is added, only do it for the groups of equal priority and
2270 * This can be called after a batch operation on task events, in which case
2271 * event_type is a bit mask of the types of events involved. For CPU events,
2272 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2274 static void ctx_resched(struct perf_cpu_context
*cpuctx
,
2275 struct perf_event_context
*task_ctx
,
2276 enum event_type_t event_type
)
2278 enum event_type_t ctx_event_type
;
2279 bool cpu_event
= !!(event_type
& EVENT_CPU
);
2282 * If pinned groups are involved, flexible groups also need to be
2285 if (event_type
& EVENT_PINNED
)
2286 event_type
|= EVENT_FLEXIBLE
;
2288 ctx_event_type
= event_type
& EVENT_ALL
;
2290 perf_pmu_disable(cpuctx
->ctx
.pmu
);
2292 task_ctx_sched_out(cpuctx
, task_ctx
, event_type
);
2295 * Decide which cpu ctx groups to schedule out based on the types
2296 * of events that caused rescheduling:
2297 * - EVENT_CPU: schedule out corresponding groups;
2298 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2299 * - otherwise, do nothing more.
2302 cpu_ctx_sched_out(cpuctx
, ctx_event_type
);
2303 else if (ctx_event_type
& EVENT_PINNED
)
2304 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
2306 perf_event_sched_in(cpuctx
, task_ctx
, current
);
2307 perf_pmu_enable(cpuctx
->ctx
.pmu
);
2311 * Cross CPU call to install and enable a performance event
2313 * Very similar to remote_function() + event_function() but cannot assume that
2314 * things like ctx->is_active and cpuctx->task_ctx are set.
2316 static int __perf_install_in_context(void *info
)
2318 struct perf_event
*event
= info
;
2319 struct perf_event_context
*ctx
= event
->ctx
;
2320 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
2321 struct perf_event_context
*task_ctx
= cpuctx
->task_ctx
;
2322 bool reprogram
= true;
2325 raw_spin_lock(&cpuctx
->ctx
.lock
);
2327 raw_spin_lock(&ctx
->lock
);
2330 reprogram
= (ctx
->task
== current
);
2333 * If the task is running, it must be running on this CPU,
2334 * otherwise we cannot reprogram things.
2336 * If its not running, we don't care, ctx->lock will
2337 * serialize against it becoming runnable.
2339 if (task_curr(ctx
->task
) && !reprogram
) {
2344 WARN_ON_ONCE(reprogram
&& cpuctx
->task_ctx
&& cpuctx
->task_ctx
!= ctx
);
2345 } else if (task_ctx
) {
2346 raw_spin_lock(&task_ctx
->lock
);
2349 #ifdef CONFIG_CGROUP_PERF
2350 if (is_cgroup_event(event
)) {
2352 * If the current cgroup doesn't match the event's
2353 * cgroup, we should not try to schedule it.
2355 struct perf_cgroup
*cgrp
= perf_cgroup_from_task(current
, ctx
);
2356 reprogram
= cgroup_is_descendant(cgrp
->css
.cgroup
,
2357 event
->cgrp
->css
.cgroup
);
2362 ctx_sched_out(ctx
, cpuctx
, EVENT_TIME
);
2363 add_event_to_ctx(event
, ctx
);
2364 ctx_resched(cpuctx
, task_ctx
, get_event_type(event
));
2366 add_event_to_ctx(event
, ctx
);
2370 perf_ctx_unlock(cpuctx
, task_ctx
);
2376 * Attach a performance event to a context.
2378 * Very similar to event_function_call, see comment there.
2381 perf_install_in_context(struct perf_event_context
*ctx
,
2382 struct perf_event
*event
,
2385 struct task_struct
*task
= READ_ONCE(ctx
->task
);
2387 lockdep_assert_held(&ctx
->mutex
);
2389 if (event
->cpu
!= -1)
2393 * Ensures that if we can observe event->ctx, both the event and ctx
2394 * will be 'complete'. See perf_iterate_sb_cpu().
2396 smp_store_release(&event
->ctx
, ctx
);
2399 cpu_function_call(cpu
, __perf_install_in_context
, event
);
2404 * Should not happen, we validate the ctx is still alive before calling.
2406 if (WARN_ON_ONCE(task
== TASK_TOMBSTONE
))
2410 * Installing events is tricky because we cannot rely on ctx->is_active
2411 * to be set in case this is the nr_events 0 -> 1 transition.
2413 * Instead we use task_curr(), which tells us if the task is running.
2414 * However, since we use task_curr() outside of rq::lock, we can race
2415 * against the actual state. This means the result can be wrong.
2417 * If we get a false positive, we retry, this is harmless.
2419 * If we get a false negative, things are complicated. If we are after
2420 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2421 * value must be correct. If we're before, it doesn't matter since
2422 * perf_event_context_sched_in() will program the counter.
2424 * However, this hinges on the remote context switch having observed
2425 * our task->perf_event_ctxp[] store, such that it will in fact take
2426 * ctx::lock in perf_event_context_sched_in().
2428 * We do this by task_function_call(), if the IPI fails to hit the task
2429 * we know any future context switch of task must see the
2430 * perf_event_ctpx[] store.
2434 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2435 * task_cpu() load, such that if the IPI then does not find the task
2436 * running, a future context switch of that task must observe the
2441 if (!task_function_call(task
, __perf_install_in_context
, event
))
2444 raw_spin_lock_irq(&ctx
->lock
);
2446 if (WARN_ON_ONCE(task
== TASK_TOMBSTONE
)) {
2448 * Cannot happen because we already checked above (which also
2449 * cannot happen), and we hold ctx->mutex, which serializes us
2450 * against perf_event_exit_task_context().
2452 raw_spin_unlock_irq(&ctx
->lock
);
2456 * If the task is not running, ctx->lock will avoid it becoming so,
2457 * thus we can safely install the event.
2459 if (task_curr(task
)) {
2460 raw_spin_unlock_irq(&ctx
->lock
);
2463 add_event_to_ctx(event
, ctx
);
2464 raw_spin_unlock_irq(&ctx
->lock
);
2468 * Cross CPU call to enable a performance event
2470 static void __perf_event_enable(struct perf_event
*event
,
2471 struct perf_cpu_context
*cpuctx
,
2472 struct perf_event_context
*ctx
,
2475 struct perf_event
*leader
= event
->group_leader
;
2476 struct perf_event_context
*task_ctx
;
2478 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
||
2479 event
->state
<= PERF_EVENT_STATE_ERROR
)
2483 ctx_sched_out(ctx
, cpuctx
, EVENT_TIME
);
2485 perf_event_set_state(event
, PERF_EVENT_STATE_INACTIVE
);
2487 if (!ctx
->is_active
)
2490 if (!event_filter_match(event
)) {
2491 ctx_sched_in(ctx
, cpuctx
, EVENT_TIME
, current
);
2496 * If the event is in a group and isn't the group leader,
2497 * then don't put it on unless the group is on.
2499 if (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
) {
2500 ctx_sched_in(ctx
, cpuctx
, EVENT_TIME
, current
);
2504 task_ctx
= cpuctx
->task_ctx
;
2506 WARN_ON_ONCE(task_ctx
!= ctx
);
2508 ctx_resched(cpuctx
, task_ctx
, get_event_type(event
));
2514 * If event->ctx is a cloned context, callers must make sure that
2515 * every task struct that event->ctx->task could possibly point to
2516 * remains valid. This condition is satisfied when called through
2517 * perf_event_for_each_child or perf_event_for_each as described
2518 * for perf_event_disable.
2520 static void _perf_event_enable(struct perf_event
*event
)
2522 struct perf_event_context
*ctx
= event
->ctx
;
2524 raw_spin_lock_irq(&ctx
->lock
);
2525 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
||
2526 event
->state
< PERF_EVENT_STATE_ERROR
) {
2527 raw_spin_unlock_irq(&ctx
->lock
);
2532 * If the event is in error state, clear that first.
2534 * That way, if we see the event in error state below, we know that it
2535 * has gone back into error state, as distinct from the task having
2536 * been scheduled away before the cross-call arrived.
2538 if (event
->state
== PERF_EVENT_STATE_ERROR
)
2539 event
->state
= PERF_EVENT_STATE_OFF
;
2540 raw_spin_unlock_irq(&ctx
->lock
);
2542 event_function_call(event
, __perf_event_enable
, NULL
);
2546 * See perf_event_disable();
2548 void perf_event_enable(struct perf_event
*event
)
2550 struct perf_event_context
*ctx
;
2552 ctx
= perf_event_ctx_lock(event
);
2553 _perf_event_enable(event
);
2554 perf_event_ctx_unlock(event
, ctx
);
2556 EXPORT_SYMBOL_GPL(perf_event_enable
);
2558 struct stop_event_data
{
2559 struct perf_event
*event
;
2560 unsigned int restart
;
2563 static int __perf_event_stop(void *info
)
2565 struct stop_event_data
*sd
= info
;
2566 struct perf_event
*event
= sd
->event
;
2568 /* if it's already INACTIVE, do nothing */
2569 if (READ_ONCE(event
->state
) != PERF_EVENT_STATE_ACTIVE
)
2572 /* matches smp_wmb() in event_sched_in() */
2576 * There is a window with interrupts enabled before we get here,
2577 * so we need to check again lest we try to stop another CPU's event.
2579 if (READ_ONCE(event
->oncpu
) != smp_processor_id())
2582 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
2585 * May race with the actual stop (through perf_pmu_output_stop()),
2586 * but it is only used for events with AUX ring buffer, and such
2587 * events will refuse to restart because of rb::aux_mmap_count==0,
2588 * see comments in perf_aux_output_begin().
2590 * Since this is happening on a event-local CPU, no trace is lost
2594 event
->pmu
->start(event
, 0);
2599 static int perf_event_stop(struct perf_event
*event
, int restart
)
2601 struct stop_event_data sd
= {
2608 if (READ_ONCE(event
->state
) != PERF_EVENT_STATE_ACTIVE
)
2611 /* matches smp_wmb() in event_sched_in() */
2615 * We only want to restart ACTIVE events, so if the event goes
2616 * inactive here (event->oncpu==-1), there's nothing more to do;
2617 * fall through with ret==-ENXIO.
2619 ret
= cpu_function_call(READ_ONCE(event
->oncpu
),
2620 __perf_event_stop
, &sd
);
2621 } while (ret
== -EAGAIN
);
2627 * In order to contain the amount of racy and tricky in the address filter
2628 * configuration management, it is a two part process:
2630 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2631 * we update the addresses of corresponding vmas in
2632 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2633 * (p2) when an event is scheduled in (pmu::add), it calls
2634 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2635 * if the generation has changed since the previous call.
2637 * If (p1) happens while the event is active, we restart it to force (p2).
2639 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2640 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2642 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2643 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2645 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2648 void perf_event_addr_filters_sync(struct perf_event
*event
)
2650 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
2652 if (!has_addr_filter(event
))
2655 raw_spin_lock(&ifh
->lock
);
2656 if (event
->addr_filters_gen
!= event
->hw
.addr_filters_gen
) {
2657 event
->pmu
->addr_filters_sync(event
);
2658 event
->hw
.addr_filters_gen
= event
->addr_filters_gen
;
2660 raw_spin_unlock(&ifh
->lock
);
2662 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync
);
2664 static int _perf_event_refresh(struct perf_event
*event
, int refresh
)
2667 * not supported on inherited events
2669 if (event
->attr
.inherit
|| !is_sampling_event(event
))
2672 atomic_add(refresh
, &event
->event_limit
);
2673 _perf_event_enable(event
);
2679 * See perf_event_disable()
2681 int perf_event_refresh(struct perf_event
*event
, int refresh
)
2683 struct perf_event_context
*ctx
;
2686 ctx
= perf_event_ctx_lock(event
);
2687 ret
= _perf_event_refresh(event
, refresh
);
2688 perf_event_ctx_unlock(event
, ctx
);
2692 EXPORT_SYMBOL_GPL(perf_event_refresh
);
2694 static void ctx_sched_out(struct perf_event_context
*ctx
,
2695 struct perf_cpu_context
*cpuctx
,
2696 enum event_type_t event_type
)
2698 int is_active
= ctx
->is_active
;
2699 struct perf_event
*event
;
2701 lockdep_assert_held(&ctx
->lock
);
2703 if (likely(!ctx
->nr_events
)) {
2705 * See __perf_remove_from_context().
2707 WARN_ON_ONCE(ctx
->is_active
);
2709 WARN_ON_ONCE(cpuctx
->task_ctx
);
2713 ctx
->is_active
&= ~event_type
;
2714 if (!(ctx
->is_active
& EVENT_ALL
))
2718 WARN_ON_ONCE(cpuctx
->task_ctx
!= ctx
);
2719 if (!ctx
->is_active
)
2720 cpuctx
->task_ctx
= NULL
;
2724 * Always update time if it was set; not only when it changes.
2725 * Otherwise we can 'forget' to update time for any but the last
2726 * context we sched out. For example:
2728 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2729 * ctx_sched_out(.event_type = EVENT_PINNED)
2731 * would only update time for the pinned events.
2733 if (is_active
& EVENT_TIME
) {
2734 /* update (and stop) ctx time */
2735 update_context_time(ctx
);
2736 update_cgrp_time_from_cpuctx(cpuctx
);
2739 is_active
^= ctx
->is_active
; /* changed bits */
2741 if (!ctx
->nr_active
|| !(is_active
& EVENT_ALL
))
2744 perf_pmu_disable(ctx
->pmu
);
2745 if (is_active
& EVENT_PINNED
) {
2746 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
)
2747 group_sched_out(event
, cpuctx
, ctx
);
2750 if (is_active
& EVENT_FLEXIBLE
) {
2751 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
)
2752 group_sched_out(event
, cpuctx
, ctx
);
2754 perf_pmu_enable(ctx
->pmu
);
2758 * Test whether two contexts are equivalent, i.e. whether they have both been
2759 * cloned from the same version of the same context.
2761 * Equivalence is measured using a generation number in the context that is
2762 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2763 * and list_del_event().
2765 static int context_equiv(struct perf_event_context
*ctx1
,
2766 struct perf_event_context
*ctx2
)
2768 lockdep_assert_held(&ctx1
->lock
);
2769 lockdep_assert_held(&ctx2
->lock
);
2771 /* Pinning disables the swap optimization */
2772 if (ctx1
->pin_count
|| ctx2
->pin_count
)
2775 /* If ctx1 is the parent of ctx2 */
2776 if (ctx1
== ctx2
->parent_ctx
&& ctx1
->generation
== ctx2
->parent_gen
)
2779 /* If ctx2 is the parent of ctx1 */
2780 if (ctx1
->parent_ctx
== ctx2
&& ctx1
->parent_gen
== ctx2
->generation
)
2784 * If ctx1 and ctx2 have the same parent; we flatten the parent
2785 * hierarchy, see perf_event_init_context().
2787 if (ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
&&
2788 ctx1
->parent_gen
== ctx2
->parent_gen
)
2795 static void __perf_event_sync_stat(struct perf_event
*event
,
2796 struct perf_event
*next_event
)
2800 if (!event
->attr
.inherit_stat
)
2804 * Update the event value, we cannot use perf_event_read()
2805 * because we're in the middle of a context switch and have IRQs
2806 * disabled, which upsets smp_call_function_single(), however
2807 * we know the event must be on the current CPU, therefore we
2808 * don't need to use it.
2810 if (event
->state
== PERF_EVENT_STATE_ACTIVE
)
2811 event
->pmu
->read(event
);
2813 perf_event_update_time(event
);
2816 * In order to keep per-task stats reliable we need to flip the event
2817 * values when we flip the contexts.
2819 value
= local64_read(&next_event
->count
);
2820 value
= local64_xchg(&event
->count
, value
);
2821 local64_set(&next_event
->count
, value
);
2823 swap(event
->total_time_enabled
, next_event
->total_time_enabled
);
2824 swap(event
->total_time_running
, next_event
->total_time_running
);
2827 * Since we swizzled the values, update the user visible data too.
2829 perf_event_update_userpage(event
);
2830 perf_event_update_userpage(next_event
);
2833 static void perf_event_sync_stat(struct perf_event_context
*ctx
,
2834 struct perf_event_context
*next_ctx
)
2836 struct perf_event
*event
, *next_event
;
2841 update_context_time(ctx
);
2843 event
= list_first_entry(&ctx
->event_list
,
2844 struct perf_event
, event_entry
);
2846 next_event
= list_first_entry(&next_ctx
->event_list
,
2847 struct perf_event
, event_entry
);
2849 while (&event
->event_entry
!= &ctx
->event_list
&&
2850 &next_event
->event_entry
!= &next_ctx
->event_list
) {
2852 __perf_event_sync_stat(event
, next_event
);
2854 event
= list_next_entry(event
, event_entry
);
2855 next_event
= list_next_entry(next_event
, event_entry
);
2859 static void perf_event_context_sched_out(struct task_struct
*task
, int ctxn
,
2860 struct task_struct
*next
)
2862 struct perf_event_context
*ctx
= task
->perf_event_ctxp
[ctxn
];
2863 struct perf_event_context
*next_ctx
;
2864 struct perf_event_context
*parent
, *next_parent
;
2865 struct perf_cpu_context
*cpuctx
;
2871 cpuctx
= __get_cpu_context(ctx
);
2872 if (!cpuctx
->task_ctx
)
2876 next_ctx
= next
->perf_event_ctxp
[ctxn
];
2880 parent
= rcu_dereference(ctx
->parent_ctx
);
2881 next_parent
= rcu_dereference(next_ctx
->parent_ctx
);
2883 /* If neither context have a parent context; they cannot be clones. */
2884 if (!parent
&& !next_parent
)
2887 if (next_parent
== ctx
|| next_ctx
== parent
|| next_parent
== parent
) {
2889 * Looks like the two contexts are clones, so we might be
2890 * able to optimize the context switch. We lock both
2891 * contexts and check that they are clones under the
2892 * lock (including re-checking that neither has been
2893 * uncloned in the meantime). It doesn't matter which
2894 * order we take the locks because no other cpu could
2895 * be trying to lock both of these tasks.
2897 raw_spin_lock(&ctx
->lock
);
2898 raw_spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
2899 if (context_equiv(ctx
, next_ctx
)) {
2900 WRITE_ONCE(ctx
->task
, next
);
2901 WRITE_ONCE(next_ctx
->task
, task
);
2903 swap(ctx
->task_ctx_data
, next_ctx
->task_ctx_data
);
2906 * RCU_INIT_POINTER here is safe because we've not
2907 * modified the ctx and the above modification of
2908 * ctx->task and ctx->task_ctx_data are immaterial
2909 * since those values are always verified under
2910 * ctx->lock which we're now holding.
2912 RCU_INIT_POINTER(task
->perf_event_ctxp
[ctxn
], next_ctx
);
2913 RCU_INIT_POINTER(next
->perf_event_ctxp
[ctxn
], ctx
);
2917 perf_event_sync_stat(ctx
, next_ctx
);
2919 raw_spin_unlock(&next_ctx
->lock
);
2920 raw_spin_unlock(&ctx
->lock
);
2926 raw_spin_lock(&ctx
->lock
);
2927 task_ctx_sched_out(cpuctx
, ctx
, EVENT_ALL
);
2928 raw_spin_unlock(&ctx
->lock
);
2932 static DEFINE_PER_CPU(struct list_head
, sched_cb_list
);
2934 void perf_sched_cb_dec(struct pmu
*pmu
)
2936 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
2938 this_cpu_dec(perf_sched_cb_usages
);
2940 if (!--cpuctx
->sched_cb_usage
)
2941 list_del(&cpuctx
->sched_cb_entry
);
2945 void perf_sched_cb_inc(struct pmu
*pmu
)
2947 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
2949 if (!cpuctx
->sched_cb_usage
++)
2950 list_add(&cpuctx
->sched_cb_entry
, this_cpu_ptr(&sched_cb_list
));
2952 this_cpu_inc(perf_sched_cb_usages
);
2956 * This function provides the context switch callback to the lower code
2957 * layer. It is invoked ONLY when the context switch callback is enabled.
2959 * This callback is relevant even to per-cpu events; for example multi event
2960 * PEBS requires this to provide PID/TID information. This requires we flush
2961 * all queued PEBS records before we context switch to a new task.
2963 static void perf_pmu_sched_task(struct task_struct
*prev
,
2964 struct task_struct
*next
,
2967 struct perf_cpu_context
*cpuctx
;
2973 list_for_each_entry(cpuctx
, this_cpu_ptr(&sched_cb_list
), sched_cb_entry
) {
2974 pmu
= cpuctx
->ctx
.pmu
; /* software PMUs will not have sched_task */
2976 if (WARN_ON_ONCE(!pmu
->sched_task
))
2979 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
2980 perf_pmu_disable(pmu
);
2982 pmu
->sched_task(cpuctx
->task_ctx
, sched_in
);
2984 perf_pmu_enable(pmu
);
2985 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
2989 static void perf_event_switch(struct task_struct
*task
,
2990 struct task_struct
*next_prev
, bool sched_in
);
2992 #define for_each_task_context_nr(ctxn) \
2993 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2996 * Called from scheduler to remove the events of the current task,
2997 * with interrupts disabled.
2999 * We stop each event and update the event value in event->count.
3001 * This does not protect us against NMI, but disable()
3002 * sets the disabled bit in the control field of event _before_
3003 * accessing the event control register. If a NMI hits, then it will
3004 * not restart the event.
3006 void __perf_event_task_sched_out(struct task_struct
*task
,
3007 struct task_struct
*next
)
3011 if (__this_cpu_read(perf_sched_cb_usages
))
3012 perf_pmu_sched_task(task
, next
, false);
3014 if (atomic_read(&nr_switch_events
))
3015 perf_event_switch(task
, next
, false);
3017 for_each_task_context_nr(ctxn
)
3018 perf_event_context_sched_out(task
, ctxn
, next
);
3021 * if cgroup events exist on this CPU, then we need
3022 * to check if we have to switch out PMU state.
3023 * cgroup event are system-wide mode only
3025 if (atomic_read(this_cpu_ptr(&perf_cgroup_events
)))
3026 perf_cgroup_sched_out(task
, next
);
3030 * Called with IRQs disabled
3032 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
3033 enum event_type_t event_type
)
3035 ctx_sched_out(&cpuctx
->ctx
, cpuctx
, event_type
);
3039 ctx_pinned_sched_in(struct perf_event_context
*ctx
,
3040 struct perf_cpu_context
*cpuctx
)
3042 struct perf_event
*event
;
3044 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
3045 if (event
->state
<= PERF_EVENT_STATE_OFF
)
3047 if (!event_filter_match(event
))
3050 if (group_can_go_on(event
, cpuctx
, 1))
3051 group_sched_in(event
, cpuctx
, ctx
);
3054 * If this pinned group hasn't been scheduled,
3055 * put it in error state.
3057 if (event
->state
== PERF_EVENT_STATE_INACTIVE
)
3058 perf_event_set_state(event
, PERF_EVENT_STATE_ERROR
);
3063 ctx_flexible_sched_in(struct perf_event_context
*ctx
,
3064 struct perf_cpu_context
*cpuctx
)
3066 struct perf_event
*event
;
3069 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
3070 /* Ignore events in OFF or ERROR state */
3071 if (event
->state
<= PERF_EVENT_STATE_OFF
)
3074 * Listen to the 'cpu' scheduling filter constraint
3077 if (!event_filter_match(event
))
3080 if (group_can_go_on(event
, cpuctx
, can_add_hw
)) {
3081 if (group_sched_in(event
, cpuctx
, ctx
))
3088 ctx_sched_in(struct perf_event_context
*ctx
,
3089 struct perf_cpu_context
*cpuctx
,
3090 enum event_type_t event_type
,
3091 struct task_struct
*task
)
3093 int is_active
= ctx
->is_active
;
3096 lockdep_assert_held(&ctx
->lock
);
3098 if (likely(!ctx
->nr_events
))
3101 ctx
->is_active
|= (event_type
| EVENT_TIME
);
3104 cpuctx
->task_ctx
= ctx
;
3106 WARN_ON_ONCE(cpuctx
->task_ctx
!= ctx
);
3109 is_active
^= ctx
->is_active
; /* changed bits */
3111 if (is_active
& EVENT_TIME
) {
3112 /* start ctx time */
3114 ctx
->timestamp
= now
;
3115 perf_cgroup_set_timestamp(task
, ctx
);
3119 * First go through the list and put on any pinned groups
3120 * in order to give them the best chance of going on.
3122 if (is_active
& EVENT_PINNED
)
3123 ctx_pinned_sched_in(ctx
, cpuctx
);
3125 /* Then walk through the lower prio flexible groups */
3126 if (is_active
& EVENT_FLEXIBLE
)
3127 ctx_flexible_sched_in(ctx
, cpuctx
);
3130 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
3131 enum event_type_t event_type
,
3132 struct task_struct
*task
)
3134 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
3136 ctx_sched_in(ctx
, cpuctx
, event_type
, task
);
3139 static void perf_event_context_sched_in(struct perf_event_context
*ctx
,
3140 struct task_struct
*task
)
3142 struct perf_cpu_context
*cpuctx
;
3144 cpuctx
= __get_cpu_context(ctx
);
3145 if (cpuctx
->task_ctx
== ctx
)
3148 perf_ctx_lock(cpuctx
, ctx
);
3150 * We must check ctx->nr_events while holding ctx->lock, such
3151 * that we serialize against perf_install_in_context().
3153 if (!ctx
->nr_events
)
3156 perf_pmu_disable(ctx
->pmu
);
3158 * We want to keep the following priority order:
3159 * cpu pinned (that don't need to move), task pinned,
3160 * cpu flexible, task flexible.
3162 * However, if task's ctx is not carrying any pinned
3163 * events, no need to flip the cpuctx's events around.
3165 if (!list_empty(&ctx
->pinned_groups
))
3166 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
3167 perf_event_sched_in(cpuctx
, ctx
, task
);
3168 perf_pmu_enable(ctx
->pmu
);
3171 perf_ctx_unlock(cpuctx
, ctx
);
3175 * Called from scheduler to add the events of the current task
3176 * with interrupts disabled.
3178 * We restore the event value and then enable it.
3180 * This does not protect us against NMI, but enable()
3181 * sets the enabled bit in the control field of event _before_
3182 * accessing the event control register. If a NMI hits, then it will
3183 * keep the event running.
3185 void __perf_event_task_sched_in(struct task_struct
*prev
,
3186 struct task_struct
*task
)
3188 struct perf_event_context
*ctx
;
3192 * If cgroup events exist on this CPU, then we need to check if we have
3193 * to switch in PMU state; cgroup event are system-wide mode only.
3195 * Since cgroup events are CPU events, we must schedule these in before
3196 * we schedule in the task events.
3198 if (atomic_read(this_cpu_ptr(&perf_cgroup_events
)))
3199 perf_cgroup_sched_in(prev
, task
);
3201 for_each_task_context_nr(ctxn
) {
3202 ctx
= task
->perf_event_ctxp
[ctxn
];
3206 perf_event_context_sched_in(ctx
, task
);
3209 if (atomic_read(&nr_switch_events
))
3210 perf_event_switch(task
, prev
, true);
3212 if (__this_cpu_read(perf_sched_cb_usages
))
3213 perf_pmu_sched_task(prev
, task
, true);
3216 static u64
perf_calculate_period(struct perf_event
*event
, u64 nsec
, u64 count
)
3218 u64 frequency
= event
->attr
.sample_freq
;
3219 u64 sec
= NSEC_PER_SEC
;
3220 u64 divisor
, dividend
;
3222 int count_fls
, nsec_fls
, frequency_fls
, sec_fls
;
3224 count_fls
= fls64(count
);
3225 nsec_fls
= fls64(nsec
);
3226 frequency_fls
= fls64(frequency
);
3230 * We got @count in @nsec, with a target of sample_freq HZ
3231 * the target period becomes:
3234 * period = -------------------
3235 * @nsec * sample_freq
3240 * Reduce accuracy by one bit such that @a and @b converge
3241 * to a similar magnitude.
3243 #define REDUCE_FLS(a, b) \
3245 if (a##_fls > b##_fls) { \
3255 * Reduce accuracy until either term fits in a u64, then proceed with
3256 * the other, so that finally we can do a u64/u64 division.
3258 while (count_fls
+ sec_fls
> 64 && nsec_fls
+ frequency_fls
> 64) {
3259 REDUCE_FLS(nsec
, frequency
);
3260 REDUCE_FLS(sec
, count
);
3263 if (count_fls
+ sec_fls
> 64) {
3264 divisor
= nsec
* frequency
;
3266 while (count_fls
+ sec_fls
> 64) {
3267 REDUCE_FLS(count
, sec
);
3271 dividend
= count
* sec
;
3273 dividend
= count
* sec
;
3275 while (nsec_fls
+ frequency_fls
> 64) {
3276 REDUCE_FLS(nsec
, frequency
);
3280 divisor
= nsec
* frequency
;
3286 return div64_u64(dividend
, divisor
);
3289 static DEFINE_PER_CPU(int, perf_throttled_count
);
3290 static DEFINE_PER_CPU(u64
, perf_throttled_seq
);
3292 static void perf_adjust_period(struct perf_event
*event
, u64 nsec
, u64 count
, bool disable
)
3294 struct hw_perf_event
*hwc
= &event
->hw
;
3295 s64 period
, sample_period
;
3298 period
= perf_calculate_period(event
, nsec
, count
);
3300 delta
= (s64
)(period
- hwc
->sample_period
);
3301 delta
= (delta
+ 7) / 8; /* low pass filter */
3303 sample_period
= hwc
->sample_period
+ delta
;
3308 hwc
->sample_period
= sample_period
;
3310 if (local64_read(&hwc
->period_left
) > 8*sample_period
) {
3312 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
3314 local64_set(&hwc
->period_left
, 0);
3317 event
->pmu
->start(event
, PERF_EF_RELOAD
);
3322 * combine freq adjustment with unthrottling to avoid two passes over the
3323 * events. At the same time, make sure, having freq events does not change
3324 * the rate of unthrottling as that would introduce bias.
3326 static void perf_adjust_freq_unthr_context(struct perf_event_context
*ctx
,
3329 struct perf_event
*event
;
3330 struct hw_perf_event
*hwc
;
3331 u64 now
, period
= TICK_NSEC
;
3335 * only need to iterate over all events iff:
3336 * - context have events in frequency mode (needs freq adjust)
3337 * - there are events to unthrottle on this cpu
3339 if (!(ctx
->nr_freq
|| needs_unthr
))
3342 raw_spin_lock(&ctx
->lock
);
3343 perf_pmu_disable(ctx
->pmu
);
3345 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3346 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
3349 if (!event_filter_match(event
))
3352 perf_pmu_disable(event
->pmu
);
3356 if (hwc
->interrupts
== MAX_INTERRUPTS
) {
3357 hwc
->interrupts
= 0;
3358 perf_log_throttle(event
, 1);
3359 event
->pmu
->start(event
, 0);
3362 if (!event
->attr
.freq
|| !event
->attr
.sample_freq
)
3366 * stop the event and update event->count
3368 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
3370 now
= local64_read(&event
->count
);
3371 delta
= now
- hwc
->freq_count_stamp
;
3372 hwc
->freq_count_stamp
= now
;
3376 * reload only if value has changed
3377 * we have stopped the event so tell that
3378 * to perf_adjust_period() to avoid stopping it
3382 perf_adjust_period(event
, period
, delta
, false);
3384 event
->pmu
->start(event
, delta
> 0 ? PERF_EF_RELOAD
: 0);
3386 perf_pmu_enable(event
->pmu
);
3389 perf_pmu_enable(ctx
->pmu
);
3390 raw_spin_unlock(&ctx
->lock
);
3394 * Round-robin a context's events:
3396 static void rotate_ctx(struct perf_event_context
*ctx
)
3399 * Rotate the first entry last of non-pinned groups. Rotation might be
3400 * disabled by the inheritance code.
3402 if (!ctx
->rotate_disable
)
3403 list_rotate_left(&ctx
->flexible_groups
);
3406 static int perf_rotate_context(struct perf_cpu_context
*cpuctx
)
3408 struct perf_event_context
*ctx
= NULL
;
3411 if (cpuctx
->ctx
.nr_events
) {
3412 if (cpuctx
->ctx
.nr_events
!= cpuctx
->ctx
.nr_active
)
3416 ctx
= cpuctx
->task_ctx
;
3417 if (ctx
&& ctx
->nr_events
) {
3418 if (ctx
->nr_events
!= ctx
->nr_active
)
3425 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
3426 perf_pmu_disable(cpuctx
->ctx
.pmu
);
3428 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
3430 ctx_sched_out(ctx
, cpuctx
, EVENT_FLEXIBLE
);
3432 rotate_ctx(&cpuctx
->ctx
);
3436 perf_event_sched_in(cpuctx
, ctx
, current
);
3438 perf_pmu_enable(cpuctx
->ctx
.pmu
);
3439 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
3445 void perf_event_task_tick(void)
3447 struct list_head
*head
= this_cpu_ptr(&active_ctx_list
);
3448 struct perf_event_context
*ctx
, *tmp
;
3451 lockdep_assert_irqs_disabled();
3453 __this_cpu_inc(perf_throttled_seq
);
3454 throttled
= __this_cpu_xchg(perf_throttled_count
, 0);
3455 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS
);
3457 list_for_each_entry_safe(ctx
, tmp
, head
, active_ctx_list
)
3458 perf_adjust_freq_unthr_context(ctx
, throttled
);
3461 static int event_enable_on_exec(struct perf_event
*event
,
3462 struct perf_event_context
*ctx
)
3464 if (!event
->attr
.enable_on_exec
)
3467 event
->attr
.enable_on_exec
= 0;
3468 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
3471 perf_event_set_state(event
, PERF_EVENT_STATE_INACTIVE
);
3477 * Enable all of a task's events that have been marked enable-on-exec.
3478 * This expects task == current.
3480 static void perf_event_enable_on_exec(int ctxn
)
3482 struct perf_event_context
*ctx
, *clone_ctx
= NULL
;
3483 enum event_type_t event_type
= 0;
3484 struct perf_cpu_context
*cpuctx
;
3485 struct perf_event
*event
;
3486 unsigned long flags
;
3489 local_irq_save(flags
);
3490 ctx
= current
->perf_event_ctxp
[ctxn
];
3491 if (!ctx
|| !ctx
->nr_events
)
3494 cpuctx
= __get_cpu_context(ctx
);
3495 perf_ctx_lock(cpuctx
, ctx
);
3496 ctx_sched_out(ctx
, cpuctx
, EVENT_TIME
);
3497 list_for_each_entry(event
, &ctx
->event_list
, event_entry
) {
3498 enabled
|= event_enable_on_exec(event
, ctx
);
3499 event_type
|= get_event_type(event
);
3503 * Unclone and reschedule this context if we enabled any event.
3506 clone_ctx
= unclone_ctx(ctx
);
3507 ctx_resched(cpuctx
, ctx
, event_type
);
3509 ctx_sched_in(ctx
, cpuctx
, EVENT_TIME
, current
);
3511 perf_ctx_unlock(cpuctx
, ctx
);
3514 local_irq_restore(flags
);
3520 struct perf_read_data
{
3521 struct perf_event
*event
;
3526 static int __perf_event_read_cpu(struct perf_event
*event
, int event_cpu
)
3528 u16 local_pkg
, event_pkg
;
3530 if (event
->group_caps
& PERF_EV_CAP_READ_ACTIVE_PKG
) {
3531 int local_cpu
= smp_processor_id();
3533 event_pkg
= topology_physical_package_id(event_cpu
);
3534 local_pkg
= topology_physical_package_id(local_cpu
);
3536 if (event_pkg
== local_pkg
)
3544 * Cross CPU call to read the hardware event
3546 static void __perf_event_read(void *info
)
3548 struct perf_read_data
*data
= info
;
3549 struct perf_event
*sub
, *event
= data
->event
;
3550 struct perf_event_context
*ctx
= event
->ctx
;
3551 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
3552 struct pmu
*pmu
= event
->pmu
;
3555 * If this is a task context, we need to check whether it is
3556 * the current task context of this cpu. If not it has been
3557 * scheduled out before the smp call arrived. In that case
3558 * event->count would have been updated to a recent sample
3559 * when the event was scheduled out.
3561 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
3564 raw_spin_lock(&ctx
->lock
);
3565 if (ctx
->is_active
& EVENT_TIME
) {
3566 update_context_time(ctx
);
3567 update_cgrp_time_from_event(event
);
3570 perf_event_update_time(event
);
3572 perf_event_update_sibling_time(event
);
3574 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
3583 pmu
->start_txn(pmu
, PERF_PMU_TXN_READ
);
3587 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
3588 if (sub
->state
== PERF_EVENT_STATE_ACTIVE
) {
3590 * Use sibling's PMU rather than @event's since
3591 * sibling could be on different (eg: software) PMU.
3593 sub
->pmu
->read(sub
);
3597 data
->ret
= pmu
->commit_txn(pmu
);
3600 raw_spin_unlock(&ctx
->lock
);
3603 static inline u64
perf_event_count(struct perf_event
*event
)
3605 return local64_read(&event
->count
) + atomic64_read(&event
->child_count
);
3609 * NMI-safe method to read a local event, that is an event that
3611 * - either for the current task, or for this CPU
3612 * - does not have inherit set, for inherited task events
3613 * will not be local and we cannot read them atomically
3614 * - must not have a pmu::count method
3616 int perf_event_read_local(struct perf_event
*event
, u64
*value
,
3617 u64
*enabled
, u64
*running
)
3619 unsigned long flags
;
3623 * Disabling interrupts avoids all counter scheduling (context
3624 * switches, timer based rotation and IPIs).
3626 local_irq_save(flags
);
3629 * It must not be an event with inherit set, we cannot read
3630 * all child counters from atomic context.
3632 if (event
->attr
.inherit
) {
3637 /* If this is a per-task event, it must be for current */
3638 if ((event
->attach_state
& PERF_ATTACH_TASK
) &&
3639 event
->hw
.target
!= current
) {
3644 /* If this is a per-CPU event, it must be for this CPU */
3645 if (!(event
->attach_state
& PERF_ATTACH_TASK
) &&
3646 event
->cpu
!= smp_processor_id()) {
3651 /* If this is a pinned event it must be running on this CPU */
3652 if (event
->attr
.pinned
&& event
->oncpu
!= smp_processor_id()) {
3658 * If the event is currently on this CPU, its either a per-task event,
3659 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3662 if (event
->oncpu
== smp_processor_id())
3663 event
->pmu
->read(event
);
3665 *value
= local64_read(&event
->count
);
3666 if (enabled
|| running
) {
3667 u64 now
= event
->shadow_ctx_time
+ perf_clock();
3668 u64 __enabled
, __running
;
3670 __perf_update_times(event
, now
, &__enabled
, &__running
);
3672 *enabled
= __enabled
;
3674 *running
= __running
;
3677 local_irq_restore(flags
);
3682 static int perf_event_read(struct perf_event
*event
, bool group
)
3684 enum perf_event_state state
= READ_ONCE(event
->state
);
3685 int event_cpu
, ret
= 0;
3688 * If event is enabled and currently active on a CPU, update the
3689 * value in the event structure:
3692 if (state
== PERF_EVENT_STATE_ACTIVE
) {
3693 struct perf_read_data data
;
3696 * Orders the ->state and ->oncpu loads such that if we see
3697 * ACTIVE we must also see the right ->oncpu.
3699 * Matches the smp_wmb() from event_sched_in().
3703 event_cpu
= READ_ONCE(event
->oncpu
);
3704 if ((unsigned)event_cpu
>= nr_cpu_ids
)
3707 data
= (struct perf_read_data
){
3714 event_cpu
= __perf_event_read_cpu(event
, event_cpu
);
3717 * Purposely ignore the smp_call_function_single() return
3720 * If event_cpu isn't a valid CPU it means the event got
3721 * scheduled out and that will have updated the event count.
3723 * Therefore, either way, we'll have an up-to-date event count
3726 (void)smp_call_function_single(event_cpu
, __perf_event_read
, &data
, 1);
3730 } else if (state
== PERF_EVENT_STATE_INACTIVE
) {
3731 struct perf_event_context
*ctx
= event
->ctx
;
3732 unsigned long flags
;
3734 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
3735 state
= event
->state
;
3736 if (state
!= PERF_EVENT_STATE_INACTIVE
) {
3737 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
3742 * May read while context is not active (e.g., thread is
3743 * blocked), in that case we cannot update context time
3745 if (ctx
->is_active
& EVENT_TIME
) {
3746 update_context_time(ctx
);
3747 update_cgrp_time_from_event(event
);
3750 perf_event_update_time(event
);
3752 perf_event_update_sibling_time(event
);
3753 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
3760 * Initialize the perf_event context in a task_struct:
3762 static void __perf_event_init_context(struct perf_event_context
*ctx
)
3764 raw_spin_lock_init(&ctx
->lock
);
3765 mutex_init(&ctx
->mutex
);
3766 INIT_LIST_HEAD(&ctx
->active_ctx_list
);
3767 INIT_LIST_HEAD(&ctx
->pinned_groups
);
3768 INIT_LIST_HEAD(&ctx
->flexible_groups
);
3769 INIT_LIST_HEAD(&ctx
->event_list
);
3770 atomic_set(&ctx
->refcount
, 1);
3773 static struct perf_event_context
*
3774 alloc_perf_context(struct pmu
*pmu
, struct task_struct
*task
)
3776 struct perf_event_context
*ctx
;
3778 ctx
= kzalloc(sizeof(struct perf_event_context
), GFP_KERNEL
);
3782 __perf_event_init_context(ctx
);
3785 get_task_struct(task
);
3792 static struct task_struct
*
3793 find_lively_task_by_vpid(pid_t vpid
)
3795 struct task_struct
*task
;
3801 task
= find_task_by_vpid(vpid
);
3803 get_task_struct(task
);
3807 return ERR_PTR(-ESRCH
);
3813 * Returns a matching context with refcount and pincount.
3815 static struct perf_event_context
*
3816 find_get_context(struct pmu
*pmu
, struct task_struct
*task
,
3817 struct perf_event
*event
)
3819 struct perf_event_context
*ctx
, *clone_ctx
= NULL
;
3820 struct perf_cpu_context
*cpuctx
;
3821 void *task_ctx_data
= NULL
;
3822 unsigned long flags
;
3824 int cpu
= event
->cpu
;
3827 /* Must be root to operate on a CPU event: */
3828 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN
))
3829 return ERR_PTR(-EACCES
);
3831 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
3840 ctxn
= pmu
->task_ctx_nr
;
3844 if (event
->attach_state
& PERF_ATTACH_TASK_DATA
) {
3845 task_ctx_data
= kzalloc(pmu
->task_ctx_size
, GFP_KERNEL
);
3846 if (!task_ctx_data
) {
3853 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
3855 clone_ctx
= unclone_ctx(ctx
);
3858 if (task_ctx_data
&& !ctx
->task_ctx_data
) {
3859 ctx
->task_ctx_data
= task_ctx_data
;
3860 task_ctx_data
= NULL
;
3862 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
3867 ctx
= alloc_perf_context(pmu
, task
);
3872 if (task_ctx_data
) {
3873 ctx
->task_ctx_data
= task_ctx_data
;
3874 task_ctx_data
= NULL
;
3878 mutex_lock(&task
->perf_event_mutex
);
3880 * If it has already passed perf_event_exit_task().
3881 * we must see PF_EXITING, it takes this mutex too.
3883 if (task
->flags
& PF_EXITING
)
3885 else if (task
->perf_event_ctxp
[ctxn
])
3890 rcu_assign_pointer(task
->perf_event_ctxp
[ctxn
], ctx
);
3892 mutex_unlock(&task
->perf_event_mutex
);
3894 if (unlikely(err
)) {
3903 kfree(task_ctx_data
);
3907 kfree(task_ctx_data
);
3908 return ERR_PTR(err
);
3911 static void perf_event_free_filter(struct perf_event
*event
);
3912 static void perf_event_free_bpf_prog(struct perf_event
*event
);
3914 static void free_event_rcu(struct rcu_head
*head
)
3916 struct perf_event
*event
;
3918 event
= container_of(head
, struct perf_event
, rcu_head
);
3920 put_pid_ns(event
->ns
);
3921 perf_event_free_filter(event
);
3925 static void ring_buffer_attach(struct perf_event
*event
,
3926 struct ring_buffer
*rb
);
3928 static void detach_sb_event(struct perf_event
*event
)
3930 struct pmu_event_list
*pel
= per_cpu_ptr(&pmu_sb_events
, event
->cpu
);
3932 raw_spin_lock(&pel
->lock
);
3933 list_del_rcu(&event
->sb_list
);
3934 raw_spin_unlock(&pel
->lock
);
3937 static bool is_sb_event(struct perf_event
*event
)
3939 struct perf_event_attr
*attr
= &event
->attr
;
3944 if (event
->attach_state
& PERF_ATTACH_TASK
)
3947 if (attr
->mmap
|| attr
->mmap_data
|| attr
->mmap2
||
3948 attr
->comm
|| attr
->comm_exec
||
3950 attr
->context_switch
)
3955 static void unaccount_pmu_sb_event(struct perf_event
*event
)
3957 if (is_sb_event(event
))
3958 detach_sb_event(event
);
3961 static void unaccount_event_cpu(struct perf_event
*event
, int cpu
)
3966 if (is_cgroup_event(event
))
3967 atomic_dec(&per_cpu(perf_cgroup_events
, cpu
));
3970 #ifdef CONFIG_NO_HZ_FULL
3971 static DEFINE_SPINLOCK(nr_freq_lock
);
3974 static void unaccount_freq_event_nohz(void)
3976 #ifdef CONFIG_NO_HZ_FULL
3977 spin_lock(&nr_freq_lock
);
3978 if (atomic_dec_and_test(&nr_freq_events
))
3979 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS
);
3980 spin_unlock(&nr_freq_lock
);
3984 static void unaccount_freq_event(void)
3986 if (tick_nohz_full_enabled())
3987 unaccount_freq_event_nohz();
3989 atomic_dec(&nr_freq_events
);
3992 static void unaccount_event(struct perf_event
*event
)
3999 if (event
->attach_state
& PERF_ATTACH_TASK
)
4001 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
4002 atomic_dec(&nr_mmap_events
);
4003 if (event
->attr
.comm
)
4004 atomic_dec(&nr_comm_events
);
4005 if (event
->attr
.namespaces
)
4006 atomic_dec(&nr_namespaces_events
);
4007 if (event
->attr
.task
)
4008 atomic_dec(&nr_task_events
);
4009 if (event
->attr
.freq
)
4010 unaccount_freq_event();
4011 if (event
->attr
.context_switch
) {
4013 atomic_dec(&nr_switch_events
);
4015 if (is_cgroup_event(event
))
4017 if (has_branch_stack(event
))
4021 if (!atomic_add_unless(&perf_sched_count
, -1, 1))
4022 schedule_delayed_work(&perf_sched_work
, HZ
);
4025 unaccount_event_cpu(event
, event
->cpu
);
4027 unaccount_pmu_sb_event(event
);
4030 static void perf_sched_delayed(struct work_struct
*work
)
4032 mutex_lock(&perf_sched_mutex
);
4033 if (atomic_dec_and_test(&perf_sched_count
))
4034 static_branch_disable(&perf_sched_events
);
4035 mutex_unlock(&perf_sched_mutex
);
4039 * The following implement mutual exclusion of events on "exclusive" pmus
4040 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4041 * at a time, so we disallow creating events that might conflict, namely:
4043 * 1) cpu-wide events in the presence of per-task events,
4044 * 2) per-task events in the presence of cpu-wide events,
4045 * 3) two matching events on the same context.
4047 * The former two cases are handled in the allocation path (perf_event_alloc(),
4048 * _free_event()), the latter -- before the first perf_install_in_context().
4050 static int exclusive_event_init(struct perf_event
*event
)
4052 struct pmu
*pmu
= event
->pmu
;
4054 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
4058 * Prevent co-existence of per-task and cpu-wide events on the
4059 * same exclusive pmu.
4061 * Negative pmu::exclusive_cnt means there are cpu-wide
4062 * events on this "exclusive" pmu, positive means there are
4065 * Since this is called in perf_event_alloc() path, event::ctx
4066 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4067 * to mean "per-task event", because unlike other attach states it
4068 * never gets cleared.
4070 if (event
->attach_state
& PERF_ATTACH_TASK
) {
4071 if (!atomic_inc_unless_negative(&pmu
->exclusive_cnt
))
4074 if (!atomic_dec_unless_positive(&pmu
->exclusive_cnt
))
4081 static void exclusive_event_destroy(struct perf_event
*event
)
4083 struct pmu
*pmu
= event
->pmu
;
4085 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
4088 /* see comment in exclusive_event_init() */
4089 if (event
->attach_state
& PERF_ATTACH_TASK
)
4090 atomic_dec(&pmu
->exclusive_cnt
);
4092 atomic_inc(&pmu
->exclusive_cnt
);
4095 static bool exclusive_event_match(struct perf_event
*e1
, struct perf_event
*e2
)
4097 if ((e1
->pmu
== e2
->pmu
) &&
4098 (e1
->cpu
== e2
->cpu
||
4105 /* Called under the same ctx::mutex as perf_install_in_context() */
4106 static bool exclusive_event_installable(struct perf_event
*event
,
4107 struct perf_event_context
*ctx
)
4109 struct perf_event
*iter_event
;
4110 struct pmu
*pmu
= event
->pmu
;
4112 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
4115 list_for_each_entry(iter_event
, &ctx
->event_list
, event_entry
) {
4116 if (exclusive_event_match(iter_event
, event
))
4123 static void perf_addr_filters_splice(struct perf_event
*event
,
4124 struct list_head
*head
);
4126 static void _free_event(struct perf_event
*event
)
4128 irq_work_sync(&event
->pending
);
4130 unaccount_event(event
);
4134 * Can happen when we close an event with re-directed output.
4136 * Since we have a 0 refcount, perf_mmap_close() will skip
4137 * over us; possibly making our ring_buffer_put() the last.
4139 mutex_lock(&event
->mmap_mutex
);
4140 ring_buffer_attach(event
, NULL
);
4141 mutex_unlock(&event
->mmap_mutex
);
4144 if (is_cgroup_event(event
))
4145 perf_detach_cgroup(event
);
4147 if (!event
->parent
) {
4148 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
)
4149 put_callchain_buffers();
4152 perf_event_free_bpf_prog(event
);
4153 perf_addr_filters_splice(event
, NULL
);
4154 kfree(event
->addr_filters_offs
);
4157 event
->destroy(event
);
4160 put_ctx(event
->ctx
);
4162 if (event
->hw
.target
)
4163 put_task_struct(event
->hw
.target
);
4165 exclusive_event_destroy(event
);
4166 module_put(event
->pmu
->module
);
4168 call_rcu(&event
->rcu_head
, free_event_rcu
);
4172 * Used to free events which have a known refcount of 1, such as in error paths
4173 * where the event isn't exposed yet and inherited events.
4175 static void free_event(struct perf_event
*event
)
4177 if (WARN(atomic_long_cmpxchg(&event
->refcount
, 1, 0) != 1,
4178 "unexpected event refcount: %ld; ptr=%p\n",
4179 atomic_long_read(&event
->refcount
), event
)) {
4180 /* leak to avoid use-after-free */
4188 * Remove user event from the owner task.
4190 static void perf_remove_from_owner(struct perf_event
*event
)
4192 struct task_struct
*owner
;
4196 * Matches the smp_store_release() in perf_event_exit_task(). If we
4197 * observe !owner it means the list deletion is complete and we can
4198 * indeed free this event, otherwise we need to serialize on
4199 * owner->perf_event_mutex.
4201 owner
= READ_ONCE(event
->owner
);
4204 * Since delayed_put_task_struct() also drops the last
4205 * task reference we can safely take a new reference
4206 * while holding the rcu_read_lock().
4208 get_task_struct(owner
);
4214 * If we're here through perf_event_exit_task() we're already
4215 * holding ctx->mutex which would be an inversion wrt. the
4216 * normal lock order.
4218 * However we can safely take this lock because its the child
4221 mutex_lock_nested(&owner
->perf_event_mutex
, SINGLE_DEPTH_NESTING
);
4224 * We have to re-check the event->owner field, if it is cleared
4225 * we raced with perf_event_exit_task(), acquiring the mutex
4226 * ensured they're done, and we can proceed with freeing the
4230 list_del_init(&event
->owner_entry
);
4231 smp_store_release(&event
->owner
, NULL
);
4233 mutex_unlock(&owner
->perf_event_mutex
);
4234 put_task_struct(owner
);
4238 static void put_event(struct perf_event
*event
)
4240 if (!atomic_long_dec_and_test(&event
->refcount
))
4247 * Kill an event dead; while event:refcount will preserve the event
4248 * object, it will not preserve its functionality. Once the last 'user'
4249 * gives up the object, we'll destroy the thing.
4251 int perf_event_release_kernel(struct perf_event
*event
)
4253 struct perf_event_context
*ctx
= event
->ctx
;
4254 struct perf_event
*child
, *tmp
;
4255 LIST_HEAD(free_list
);
4258 * If we got here through err_file: fput(event_file); we will not have
4259 * attached to a context yet.
4262 WARN_ON_ONCE(event
->attach_state
&
4263 (PERF_ATTACH_CONTEXT
|PERF_ATTACH_GROUP
));
4267 if (!is_kernel_event(event
))
4268 perf_remove_from_owner(event
);
4270 ctx
= perf_event_ctx_lock(event
);
4271 WARN_ON_ONCE(ctx
->parent_ctx
);
4272 perf_remove_from_context(event
, DETACH_GROUP
);
4274 raw_spin_lock_irq(&ctx
->lock
);
4276 * Mark this event as STATE_DEAD, there is no external reference to it
4279 * Anybody acquiring event->child_mutex after the below loop _must_
4280 * also see this, most importantly inherit_event() which will avoid
4281 * placing more children on the list.
4283 * Thus this guarantees that we will in fact observe and kill _ALL_
4286 event
->state
= PERF_EVENT_STATE_DEAD
;
4287 raw_spin_unlock_irq(&ctx
->lock
);
4289 perf_event_ctx_unlock(event
, ctx
);
4292 mutex_lock(&event
->child_mutex
);
4293 list_for_each_entry(child
, &event
->child_list
, child_list
) {
4296 * Cannot change, child events are not migrated, see the
4297 * comment with perf_event_ctx_lock_nested().
4299 ctx
= READ_ONCE(child
->ctx
);
4301 * Since child_mutex nests inside ctx::mutex, we must jump
4302 * through hoops. We start by grabbing a reference on the ctx.
4304 * Since the event cannot get freed while we hold the
4305 * child_mutex, the context must also exist and have a !0
4311 * Now that we have a ctx ref, we can drop child_mutex, and
4312 * acquire ctx::mutex without fear of it going away. Then we
4313 * can re-acquire child_mutex.
4315 mutex_unlock(&event
->child_mutex
);
4316 mutex_lock(&ctx
->mutex
);
4317 mutex_lock(&event
->child_mutex
);
4320 * Now that we hold ctx::mutex and child_mutex, revalidate our
4321 * state, if child is still the first entry, it didn't get freed
4322 * and we can continue doing so.
4324 tmp
= list_first_entry_or_null(&event
->child_list
,
4325 struct perf_event
, child_list
);
4327 perf_remove_from_context(child
, DETACH_GROUP
);
4328 list_move(&child
->child_list
, &free_list
);
4330 * This matches the refcount bump in inherit_event();
4331 * this can't be the last reference.
4336 mutex_unlock(&event
->child_mutex
);
4337 mutex_unlock(&ctx
->mutex
);
4341 mutex_unlock(&event
->child_mutex
);
4343 list_for_each_entry_safe(child
, tmp
, &free_list
, child_list
) {
4344 list_del(&child
->child_list
);
4349 put_event(event
); /* Must be the 'last' reference */
4352 EXPORT_SYMBOL_GPL(perf_event_release_kernel
);
4355 * Called when the last reference to the file is gone.
4357 static int perf_release(struct inode
*inode
, struct file
*file
)
4359 perf_event_release_kernel(file
->private_data
);
4363 static u64
__perf_event_read_value(struct perf_event
*event
, u64
*enabled
, u64
*running
)
4365 struct perf_event
*child
;
4371 mutex_lock(&event
->child_mutex
);
4373 (void)perf_event_read(event
, false);
4374 total
+= perf_event_count(event
);
4376 *enabled
+= event
->total_time_enabled
+
4377 atomic64_read(&event
->child_total_time_enabled
);
4378 *running
+= event
->total_time_running
+
4379 atomic64_read(&event
->child_total_time_running
);
4381 list_for_each_entry(child
, &event
->child_list
, child_list
) {
4382 (void)perf_event_read(child
, false);
4383 total
+= perf_event_count(child
);
4384 *enabled
+= child
->total_time_enabled
;
4385 *running
+= child
->total_time_running
;
4387 mutex_unlock(&event
->child_mutex
);
4392 u64
perf_event_read_value(struct perf_event
*event
, u64
*enabled
, u64
*running
)
4394 struct perf_event_context
*ctx
;
4397 ctx
= perf_event_ctx_lock(event
);
4398 count
= __perf_event_read_value(event
, enabled
, running
);
4399 perf_event_ctx_unlock(event
, ctx
);
4403 EXPORT_SYMBOL_GPL(perf_event_read_value
);
4405 static int __perf_read_group_add(struct perf_event
*leader
,
4406 u64 read_format
, u64
*values
)
4408 struct perf_event_context
*ctx
= leader
->ctx
;
4409 struct perf_event
*sub
;
4410 unsigned long flags
;
4411 int n
= 1; /* skip @nr */
4414 ret
= perf_event_read(leader
, true);
4418 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
4421 * Since we co-schedule groups, {enabled,running} times of siblings
4422 * will be identical to those of the leader, so we only publish one
4425 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
4426 values
[n
++] += leader
->total_time_enabled
+
4427 atomic64_read(&leader
->child_total_time_enabled
);
4430 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
4431 values
[n
++] += leader
->total_time_running
+
4432 atomic64_read(&leader
->child_total_time_running
);
4436 * Write {count,id} tuples for every sibling.
4438 values
[n
++] += perf_event_count(leader
);
4439 if (read_format
& PERF_FORMAT_ID
)
4440 values
[n
++] = primary_event_id(leader
);
4442 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
4443 values
[n
++] += perf_event_count(sub
);
4444 if (read_format
& PERF_FORMAT_ID
)
4445 values
[n
++] = primary_event_id(sub
);
4448 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
4452 static int perf_read_group(struct perf_event
*event
,
4453 u64 read_format
, char __user
*buf
)
4455 struct perf_event
*leader
= event
->group_leader
, *child
;
4456 struct perf_event_context
*ctx
= leader
->ctx
;
4460 lockdep_assert_held(&ctx
->mutex
);
4462 values
= kzalloc(event
->read_size
, GFP_KERNEL
);
4466 values
[0] = 1 + leader
->nr_siblings
;
4469 * By locking the child_mutex of the leader we effectively
4470 * lock the child list of all siblings.. XXX explain how.
4472 mutex_lock(&leader
->child_mutex
);
4474 ret
= __perf_read_group_add(leader
, read_format
, values
);
4478 list_for_each_entry(child
, &leader
->child_list
, child_list
) {
4479 ret
= __perf_read_group_add(child
, read_format
, values
);
4484 mutex_unlock(&leader
->child_mutex
);
4486 ret
= event
->read_size
;
4487 if (copy_to_user(buf
, values
, event
->read_size
))
4492 mutex_unlock(&leader
->child_mutex
);
4498 static int perf_read_one(struct perf_event
*event
,
4499 u64 read_format
, char __user
*buf
)
4501 u64 enabled
, running
;
4505 values
[n
++] = __perf_event_read_value(event
, &enabled
, &running
);
4506 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
4507 values
[n
++] = enabled
;
4508 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
4509 values
[n
++] = running
;
4510 if (read_format
& PERF_FORMAT_ID
)
4511 values
[n
++] = primary_event_id(event
);
4513 if (copy_to_user(buf
, values
, n
* sizeof(u64
)))
4516 return n
* sizeof(u64
);
4519 static bool is_event_hup(struct perf_event
*event
)
4523 if (event
->state
> PERF_EVENT_STATE_EXIT
)
4526 mutex_lock(&event
->child_mutex
);
4527 no_children
= list_empty(&event
->child_list
);
4528 mutex_unlock(&event
->child_mutex
);
4533 * Read the performance event - simple non blocking version for now
4536 __perf_read(struct perf_event
*event
, char __user
*buf
, size_t count
)
4538 u64 read_format
= event
->attr
.read_format
;
4542 * Return end-of-file for a read on a event that is in
4543 * error state (i.e. because it was pinned but it couldn't be
4544 * scheduled on to the CPU at some point).
4546 if (event
->state
== PERF_EVENT_STATE_ERROR
)
4549 if (count
< event
->read_size
)
4552 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
4553 if (read_format
& PERF_FORMAT_GROUP
)
4554 ret
= perf_read_group(event
, read_format
, buf
);
4556 ret
= perf_read_one(event
, read_format
, buf
);
4562 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
4564 struct perf_event
*event
= file
->private_data
;
4565 struct perf_event_context
*ctx
;
4568 ctx
= perf_event_ctx_lock(event
);
4569 ret
= __perf_read(event
, buf
, count
);
4570 perf_event_ctx_unlock(event
, ctx
);
4575 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
4577 struct perf_event
*event
= file
->private_data
;
4578 struct ring_buffer
*rb
;
4579 unsigned int events
= POLLHUP
;
4581 poll_wait(file
, &event
->waitq
, wait
);
4583 if (is_event_hup(event
))
4587 * Pin the event->rb by taking event->mmap_mutex; otherwise
4588 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4590 mutex_lock(&event
->mmap_mutex
);
4593 events
= atomic_xchg(&rb
->poll
, 0);
4594 mutex_unlock(&event
->mmap_mutex
);
4598 static void _perf_event_reset(struct perf_event
*event
)
4600 (void)perf_event_read(event
, false);
4601 local64_set(&event
->count
, 0);
4602 perf_event_update_userpage(event
);
4606 * Holding the top-level event's child_mutex means that any
4607 * descendant process that has inherited this event will block
4608 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4609 * task existence requirements of perf_event_enable/disable.
4611 static void perf_event_for_each_child(struct perf_event
*event
,
4612 void (*func
)(struct perf_event
*))
4614 struct perf_event
*child
;
4616 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
4618 mutex_lock(&event
->child_mutex
);
4620 list_for_each_entry(child
, &event
->child_list
, child_list
)
4622 mutex_unlock(&event
->child_mutex
);
4625 static void perf_event_for_each(struct perf_event
*event
,
4626 void (*func
)(struct perf_event
*))
4628 struct perf_event_context
*ctx
= event
->ctx
;
4629 struct perf_event
*sibling
;
4631 lockdep_assert_held(&ctx
->mutex
);
4633 event
= event
->group_leader
;
4635 perf_event_for_each_child(event
, func
);
4636 list_for_each_entry(sibling
, &event
->sibling_list
, group_entry
)
4637 perf_event_for_each_child(sibling
, func
);
4640 static void __perf_event_period(struct perf_event
*event
,
4641 struct perf_cpu_context
*cpuctx
,
4642 struct perf_event_context
*ctx
,
4645 u64 value
= *((u64
*)info
);
4648 if (event
->attr
.freq
) {
4649 event
->attr
.sample_freq
= value
;
4651 event
->attr
.sample_period
= value
;
4652 event
->hw
.sample_period
= value
;
4655 active
= (event
->state
== PERF_EVENT_STATE_ACTIVE
);
4657 perf_pmu_disable(ctx
->pmu
);
4659 * We could be throttled; unthrottle now to avoid the tick
4660 * trying to unthrottle while we already re-started the event.
4662 if (event
->hw
.interrupts
== MAX_INTERRUPTS
) {
4663 event
->hw
.interrupts
= 0;
4664 perf_log_throttle(event
, 1);
4666 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
4669 local64_set(&event
->hw
.period_left
, 0);
4672 event
->pmu
->start(event
, PERF_EF_RELOAD
);
4673 perf_pmu_enable(ctx
->pmu
);
4677 static int perf_event_check_period(struct perf_event
*event
, u64 value
)
4679 return event
->pmu
->check_period(event
, value
);
4682 static int perf_event_period(struct perf_event
*event
, u64 __user
*arg
)
4686 if (!is_sampling_event(event
))
4689 if (copy_from_user(&value
, arg
, sizeof(value
)))
4695 if (event
->attr
.freq
&& value
> sysctl_perf_event_sample_rate
)
4698 if (perf_event_check_period(event
, value
))
4701 event_function_call(event
, __perf_event_period
, &value
);
4706 static const struct file_operations perf_fops
;
4708 static inline int perf_fget_light(int fd
, struct fd
*p
)
4710 struct fd f
= fdget(fd
);
4714 if (f
.file
->f_op
!= &perf_fops
) {
4722 static int perf_event_set_output(struct perf_event
*event
,
4723 struct perf_event
*output_event
);
4724 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
);
4725 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
);
4727 static long _perf_ioctl(struct perf_event
*event
, unsigned int cmd
, unsigned long arg
)
4729 void (*func
)(struct perf_event
*);
4733 case PERF_EVENT_IOC_ENABLE
:
4734 func
= _perf_event_enable
;
4736 case PERF_EVENT_IOC_DISABLE
:
4737 func
= _perf_event_disable
;
4739 case PERF_EVENT_IOC_RESET
:
4740 func
= _perf_event_reset
;
4743 case PERF_EVENT_IOC_REFRESH
:
4744 return _perf_event_refresh(event
, arg
);
4746 case PERF_EVENT_IOC_PERIOD
:
4747 return perf_event_period(event
, (u64 __user
*)arg
);
4749 case PERF_EVENT_IOC_ID
:
4751 u64 id
= primary_event_id(event
);
4753 if (copy_to_user((void __user
*)arg
, &id
, sizeof(id
)))
4758 case PERF_EVENT_IOC_SET_OUTPUT
:
4762 struct perf_event
*output_event
;
4764 ret
= perf_fget_light(arg
, &output
);
4767 output_event
= output
.file
->private_data
;
4768 ret
= perf_event_set_output(event
, output_event
);
4771 ret
= perf_event_set_output(event
, NULL
);
4776 case PERF_EVENT_IOC_SET_FILTER
:
4777 return perf_event_set_filter(event
, (void __user
*)arg
);
4779 case PERF_EVENT_IOC_SET_BPF
:
4780 return perf_event_set_bpf_prog(event
, arg
);
4782 case PERF_EVENT_IOC_PAUSE_OUTPUT
: {
4783 struct ring_buffer
*rb
;
4786 rb
= rcu_dereference(event
->rb
);
4787 if (!rb
|| !rb
->nr_pages
) {
4791 rb_toggle_paused(rb
, !!arg
);
4799 if (flags
& PERF_IOC_FLAG_GROUP
)
4800 perf_event_for_each(event
, func
);
4802 perf_event_for_each_child(event
, func
);
4807 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
4809 struct perf_event
*event
= file
->private_data
;
4810 struct perf_event_context
*ctx
;
4813 ctx
= perf_event_ctx_lock(event
);
4814 ret
= _perf_ioctl(event
, cmd
, arg
);
4815 perf_event_ctx_unlock(event
, ctx
);
4820 #ifdef CONFIG_COMPAT
4821 static long perf_compat_ioctl(struct file
*file
, unsigned int cmd
,
4824 switch (_IOC_NR(cmd
)) {
4825 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER
):
4826 case _IOC_NR(PERF_EVENT_IOC_ID
):
4827 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4828 if (_IOC_SIZE(cmd
) == sizeof(compat_uptr_t
)) {
4829 cmd
&= ~IOCSIZE_MASK
;
4830 cmd
|= sizeof(void *) << IOCSIZE_SHIFT
;
4834 return perf_ioctl(file
, cmd
, arg
);
4837 # define perf_compat_ioctl NULL
4840 int perf_event_task_enable(void)
4842 struct perf_event_context
*ctx
;
4843 struct perf_event
*event
;
4845 mutex_lock(¤t
->perf_event_mutex
);
4846 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
) {
4847 ctx
= perf_event_ctx_lock(event
);
4848 perf_event_for_each_child(event
, _perf_event_enable
);
4849 perf_event_ctx_unlock(event
, ctx
);
4851 mutex_unlock(¤t
->perf_event_mutex
);
4856 int perf_event_task_disable(void)
4858 struct perf_event_context
*ctx
;
4859 struct perf_event
*event
;
4861 mutex_lock(¤t
->perf_event_mutex
);
4862 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
) {
4863 ctx
= perf_event_ctx_lock(event
);
4864 perf_event_for_each_child(event
, _perf_event_disable
);
4865 perf_event_ctx_unlock(event
, ctx
);
4867 mutex_unlock(¤t
->perf_event_mutex
);
4872 static int perf_event_index(struct perf_event
*event
)
4874 if (event
->hw
.state
& PERF_HES_STOPPED
)
4877 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
4880 return event
->pmu
->event_idx(event
);
4883 static void calc_timer_values(struct perf_event
*event
,
4890 *now
= perf_clock();
4891 ctx_time
= event
->shadow_ctx_time
+ *now
;
4892 __perf_update_times(event
, ctx_time
, enabled
, running
);
4895 static void perf_event_init_userpage(struct perf_event
*event
)
4897 struct perf_event_mmap_page
*userpg
;
4898 struct ring_buffer
*rb
;
4901 rb
= rcu_dereference(event
->rb
);
4905 userpg
= rb
->user_page
;
4907 /* Allow new userspace to detect that bit 0 is deprecated */
4908 userpg
->cap_bit0_is_deprecated
= 1;
4909 userpg
->size
= offsetof(struct perf_event_mmap_page
, __reserved
);
4910 userpg
->data_offset
= PAGE_SIZE
;
4911 userpg
->data_size
= perf_data_size(rb
);
4917 void __weak
arch_perf_update_userpage(
4918 struct perf_event
*event
, struct perf_event_mmap_page
*userpg
, u64 now
)
4923 * Callers need to ensure there can be no nesting of this function, otherwise
4924 * the seqlock logic goes bad. We can not serialize this because the arch
4925 * code calls this from NMI context.
4927 void perf_event_update_userpage(struct perf_event
*event
)
4929 struct perf_event_mmap_page
*userpg
;
4930 struct ring_buffer
*rb
;
4931 u64 enabled
, running
, now
;
4934 rb
= rcu_dereference(event
->rb
);
4939 * compute total_time_enabled, total_time_running
4940 * based on snapshot values taken when the event
4941 * was last scheduled in.
4943 * we cannot simply called update_context_time()
4944 * because of locking issue as we can be called in
4947 calc_timer_values(event
, &now
, &enabled
, &running
);
4949 userpg
= rb
->user_page
;
4951 * Disable preemption so as to not let the corresponding user-space
4952 * spin too long if we get preempted.
4957 userpg
->index
= perf_event_index(event
);
4958 userpg
->offset
= perf_event_count(event
);
4960 userpg
->offset
-= local64_read(&event
->hw
.prev_count
);
4962 userpg
->time_enabled
= enabled
+
4963 atomic64_read(&event
->child_total_time_enabled
);
4965 userpg
->time_running
= running
+
4966 atomic64_read(&event
->child_total_time_running
);
4968 arch_perf_update_userpage(event
, userpg
, now
);
4976 EXPORT_SYMBOL_GPL(perf_event_update_userpage
);
4978 static int perf_mmap_fault(struct vm_fault
*vmf
)
4980 struct perf_event
*event
= vmf
->vma
->vm_file
->private_data
;
4981 struct ring_buffer
*rb
;
4982 int ret
= VM_FAULT_SIGBUS
;
4984 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
4985 if (vmf
->pgoff
== 0)
4991 rb
= rcu_dereference(event
->rb
);
4995 if (vmf
->pgoff
&& (vmf
->flags
& FAULT_FLAG_WRITE
))
4998 vmf
->page
= perf_mmap_to_page(rb
, vmf
->pgoff
);
5002 get_page(vmf
->page
);
5003 vmf
->page
->mapping
= vmf
->vma
->vm_file
->f_mapping
;
5004 vmf
->page
->index
= vmf
->pgoff
;
5013 static void ring_buffer_attach(struct perf_event
*event
,
5014 struct ring_buffer
*rb
)
5016 struct ring_buffer
*old_rb
= NULL
;
5017 unsigned long flags
;
5021 * Should be impossible, we set this when removing
5022 * event->rb_entry and wait/clear when adding event->rb_entry.
5024 WARN_ON_ONCE(event
->rcu_pending
);
5027 spin_lock_irqsave(&old_rb
->event_lock
, flags
);
5028 list_del_rcu(&event
->rb_entry
);
5029 spin_unlock_irqrestore(&old_rb
->event_lock
, flags
);
5031 event
->rcu_batches
= get_state_synchronize_rcu();
5032 event
->rcu_pending
= 1;
5036 if (event
->rcu_pending
) {
5037 cond_synchronize_rcu(event
->rcu_batches
);
5038 event
->rcu_pending
= 0;
5041 spin_lock_irqsave(&rb
->event_lock
, flags
);
5042 list_add_rcu(&event
->rb_entry
, &rb
->event_list
);
5043 spin_unlock_irqrestore(&rb
->event_lock
, flags
);
5047 * Avoid racing with perf_mmap_close(AUX): stop the event
5048 * before swizzling the event::rb pointer; if it's getting
5049 * unmapped, its aux_mmap_count will be 0 and it won't
5050 * restart. See the comment in __perf_pmu_output_stop().
5052 * Data will inevitably be lost when set_output is done in
5053 * mid-air, but then again, whoever does it like this is
5054 * not in for the data anyway.
5057 perf_event_stop(event
, 0);
5059 rcu_assign_pointer(event
->rb
, rb
);
5062 ring_buffer_put(old_rb
);
5064 * Since we detached before setting the new rb, so that we
5065 * could attach the new rb, we could have missed a wakeup.
5068 wake_up_all(&event
->waitq
);
5072 static void ring_buffer_wakeup(struct perf_event
*event
)
5074 struct ring_buffer
*rb
;
5077 rb
= rcu_dereference(event
->rb
);
5079 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
)
5080 wake_up_all(&event
->waitq
);
5085 struct ring_buffer
*ring_buffer_get(struct perf_event
*event
)
5087 struct ring_buffer
*rb
;
5090 rb
= rcu_dereference(event
->rb
);
5092 if (!atomic_inc_not_zero(&rb
->refcount
))
5100 void ring_buffer_put(struct ring_buffer
*rb
)
5102 if (!atomic_dec_and_test(&rb
->refcount
))
5105 WARN_ON_ONCE(!list_empty(&rb
->event_list
));
5107 call_rcu(&rb
->rcu_head
, rb_free_rcu
);
5110 static void perf_mmap_open(struct vm_area_struct
*vma
)
5112 struct perf_event
*event
= vma
->vm_file
->private_data
;
5114 atomic_inc(&event
->mmap_count
);
5115 atomic_inc(&event
->rb
->mmap_count
);
5118 atomic_inc(&event
->rb
->aux_mmap_count
);
5120 if (event
->pmu
->event_mapped
)
5121 event
->pmu
->event_mapped(event
, vma
->vm_mm
);
5124 static void perf_pmu_output_stop(struct perf_event
*event
);
5127 * A buffer can be mmap()ed multiple times; either directly through the same
5128 * event, or through other events by use of perf_event_set_output().
5130 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5131 * the buffer here, where we still have a VM context. This means we need
5132 * to detach all events redirecting to us.
5134 static void perf_mmap_close(struct vm_area_struct
*vma
)
5136 struct perf_event
*event
= vma
->vm_file
->private_data
;
5138 struct ring_buffer
*rb
= ring_buffer_get(event
);
5139 struct user_struct
*mmap_user
= rb
->mmap_user
;
5140 int mmap_locked
= rb
->mmap_locked
;
5141 unsigned long size
= perf_data_size(rb
);
5143 if (event
->pmu
->event_unmapped
)
5144 event
->pmu
->event_unmapped(event
, vma
->vm_mm
);
5147 * rb->aux_mmap_count will always drop before rb->mmap_count and
5148 * event->mmap_count, so it is ok to use event->mmap_mutex to
5149 * serialize with perf_mmap here.
5151 if (rb_has_aux(rb
) && vma
->vm_pgoff
== rb
->aux_pgoff
&&
5152 atomic_dec_and_mutex_lock(&rb
->aux_mmap_count
, &event
->mmap_mutex
)) {
5154 * Stop all AUX events that are writing to this buffer,
5155 * so that we can free its AUX pages and corresponding PMU
5156 * data. Note that after rb::aux_mmap_count dropped to zero,
5157 * they won't start any more (see perf_aux_output_begin()).
5159 perf_pmu_output_stop(event
);
5161 /* now it's safe to free the pages */
5162 atomic_long_sub(rb
->aux_nr_pages
, &mmap_user
->locked_vm
);
5163 vma
->vm_mm
->pinned_vm
-= rb
->aux_mmap_locked
;
5165 /* this has to be the last one */
5167 WARN_ON_ONCE(atomic_read(&rb
->aux_refcount
));
5169 mutex_unlock(&event
->mmap_mutex
);
5172 atomic_dec(&rb
->mmap_count
);
5174 if (!atomic_dec_and_mutex_lock(&event
->mmap_count
, &event
->mmap_mutex
))
5177 ring_buffer_attach(event
, NULL
);
5178 mutex_unlock(&event
->mmap_mutex
);
5180 /* If there's still other mmap()s of this buffer, we're done. */
5181 if (atomic_read(&rb
->mmap_count
))
5185 * No other mmap()s, detach from all other events that might redirect
5186 * into the now unreachable buffer. Somewhat complicated by the
5187 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5191 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
) {
5192 if (!atomic_long_inc_not_zero(&event
->refcount
)) {
5194 * This event is en-route to free_event() which will
5195 * detach it and remove it from the list.
5201 mutex_lock(&event
->mmap_mutex
);
5203 * Check we didn't race with perf_event_set_output() which can
5204 * swizzle the rb from under us while we were waiting to
5205 * acquire mmap_mutex.
5207 * If we find a different rb; ignore this event, a next
5208 * iteration will no longer find it on the list. We have to
5209 * still restart the iteration to make sure we're not now
5210 * iterating the wrong list.
5212 if (event
->rb
== rb
)
5213 ring_buffer_attach(event
, NULL
);
5215 mutex_unlock(&event
->mmap_mutex
);
5219 * Restart the iteration; either we're on the wrong list or
5220 * destroyed its integrity by doing a deletion.
5227 * It could be there's still a few 0-ref events on the list; they'll
5228 * get cleaned up by free_event() -- they'll also still have their
5229 * ref on the rb and will free it whenever they are done with it.
5231 * Aside from that, this buffer is 'fully' detached and unmapped,
5232 * undo the VM accounting.
5235 atomic_long_sub((size
>> PAGE_SHIFT
) + 1, &mmap_user
->locked_vm
);
5236 vma
->vm_mm
->pinned_vm
-= mmap_locked
;
5237 free_uid(mmap_user
);
5240 ring_buffer_put(rb
); /* could be last */
5243 static const struct vm_operations_struct perf_mmap_vmops
= {
5244 .open
= perf_mmap_open
,
5245 .close
= perf_mmap_close
, /* non mergable */
5246 .fault
= perf_mmap_fault
,
5247 .page_mkwrite
= perf_mmap_fault
,
5250 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
5252 struct perf_event
*event
= file
->private_data
;
5253 unsigned long user_locked
, user_lock_limit
;
5254 struct user_struct
*user
= current_user();
5255 unsigned long locked
, lock_limit
;
5256 struct ring_buffer
*rb
= NULL
;
5257 unsigned long vma_size
;
5258 unsigned long nr_pages
;
5259 long user_extra
= 0, extra
= 0;
5260 int ret
= 0, flags
= 0;
5263 * Don't allow mmap() of inherited per-task counters. This would
5264 * create a performance issue due to all children writing to the
5267 if (event
->cpu
== -1 && event
->attr
.inherit
)
5270 if (!(vma
->vm_flags
& VM_SHARED
))
5273 vma_size
= vma
->vm_end
- vma
->vm_start
;
5275 if (vma
->vm_pgoff
== 0) {
5276 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
5279 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5280 * mapped, all subsequent mappings should have the same size
5281 * and offset. Must be above the normal perf buffer.
5283 u64 aux_offset
, aux_size
;
5288 nr_pages
= vma_size
/ PAGE_SIZE
;
5290 mutex_lock(&event
->mmap_mutex
);
5297 aux_offset
= READ_ONCE(rb
->user_page
->aux_offset
);
5298 aux_size
= READ_ONCE(rb
->user_page
->aux_size
);
5300 if (aux_offset
< perf_data_size(rb
) + PAGE_SIZE
)
5303 if (aux_offset
!= vma
->vm_pgoff
<< PAGE_SHIFT
)
5306 /* already mapped with a different offset */
5307 if (rb_has_aux(rb
) && rb
->aux_pgoff
!= vma
->vm_pgoff
)
5310 if (aux_size
!= vma_size
|| aux_size
!= nr_pages
* PAGE_SIZE
)
5313 /* already mapped with a different size */
5314 if (rb_has_aux(rb
) && rb
->aux_nr_pages
!= nr_pages
)
5317 if (!is_power_of_2(nr_pages
))
5320 if (!atomic_inc_not_zero(&rb
->mmap_count
))
5323 if (rb_has_aux(rb
)) {
5324 atomic_inc(&rb
->aux_mmap_count
);
5329 atomic_set(&rb
->aux_mmap_count
, 1);
5330 user_extra
= nr_pages
;
5336 * If we have rb pages ensure they're a power-of-two number, so we
5337 * can do bitmasks instead of modulo.
5339 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
5342 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
5345 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
5347 mutex_lock(&event
->mmap_mutex
);
5349 if (event
->rb
->nr_pages
!= nr_pages
) {
5354 if (!atomic_inc_not_zero(&event
->rb
->mmap_count
)) {
5356 * Raced against perf_mmap_close() through
5357 * perf_event_set_output(). Try again, hope for better
5360 mutex_unlock(&event
->mmap_mutex
);
5367 user_extra
= nr_pages
+ 1;
5370 user_lock_limit
= sysctl_perf_event_mlock
>> (PAGE_SHIFT
- 10);
5373 * Increase the limit linearly with more CPUs:
5375 user_lock_limit
*= num_online_cpus();
5377 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
5379 if (user_locked
> user_lock_limit
)
5380 extra
= user_locked
- user_lock_limit
;
5382 lock_limit
= rlimit(RLIMIT_MEMLOCK
);
5383 lock_limit
>>= PAGE_SHIFT
;
5384 locked
= vma
->vm_mm
->pinned_vm
+ extra
;
5386 if ((locked
> lock_limit
) && perf_paranoid_tracepoint_raw() &&
5387 !capable(CAP_IPC_LOCK
)) {
5392 WARN_ON(!rb
&& event
->rb
);
5394 if (vma
->vm_flags
& VM_WRITE
)
5395 flags
|= RING_BUFFER_WRITABLE
;
5398 rb
= rb_alloc(nr_pages
,
5399 event
->attr
.watermark
? event
->attr
.wakeup_watermark
: 0,
5407 atomic_set(&rb
->mmap_count
, 1);
5408 rb
->mmap_user
= get_current_user();
5409 rb
->mmap_locked
= extra
;
5411 ring_buffer_attach(event
, rb
);
5413 perf_event_init_userpage(event
);
5414 perf_event_update_userpage(event
);
5416 ret
= rb_alloc_aux(rb
, event
, vma
->vm_pgoff
, nr_pages
,
5417 event
->attr
.aux_watermark
, flags
);
5419 rb
->aux_mmap_locked
= extra
;
5424 atomic_long_add(user_extra
, &user
->locked_vm
);
5425 vma
->vm_mm
->pinned_vm
+= extra
;
5427 atomic_inc(&event
->mmap_count
);
5429 atomic_dec(&rb
->mmap_count
);
5432 mutex_unlock(&event
->mmap_mutex
);
5435 * Since pinned accounting is per vm we cannot allow fork() to copy our
5438 vma
->vm_flags
|= VM_DONTCOPY
| VM_DONTEXPAND
| VM_DONTDUMP
;
5439 vma
->vm_ops
= &perf_mmap_vmops
;
5441 if (event
->pmu
->event_mapped
)
5442 event
->pmu
->event_mapped(event
, vma
->vm_mm
);
5447 static int perf_fasync(int fd
, struct file
*filp
, int on
)
5449 struct inode
*inode
= file_inode(filp
);
5450 struct perf_event
*event
= filp
->private_data
;
5454 retval
= fasync_helper(fd
, filp
, on
, &event
->fasync
);
5455 inode_unlock(inode
);
5463 static const struct file_operations perf_fops
= {
5464 .llseek
= no_llseek
,
5465 .release
= perf_release
,
5468 .unlocked_ioctl
= perf_ioctl
,
5469 .compat_ioctl
= perf_compat_ioctl
,
5471 .fasync
= perf_fasync
,
5477 * If there's data, ensure we set the poll() state and publish everything
5478 * to user-space before waking everybody up.
5481 static inline struct fasync_struct
**perf_event_fasync(struct perf_event
*event
)
5483 /* only the parent has fasync state */
5485 event
= event
->parent
;
5486 return &event
->fasync
;
5489 void perf_event_wakeup(struct perf_event
*event
)
5491 ring_buffer_wakeup(event
);
5493 if (event
->pending_kill
) {
5494 kill_fasync(perf_event_fasync(event
), SIGIO
, event
->pending_kill
);
5495 event
->pending_kill
= 0;
5499 static void perf_pending_event_disable(struct perf_event
*event
)
5501 int cpu
= READ_ONCE(event
->pending_disable
);
5506 if (cpu
== smp_processor_id()) {
5507 WRITE_ONCE(event
->pending_disable
, -1);
5508 perf_event_disable_local(event
);
5515 * perf_event_disable_inatomic()
5516 * @pending_disable = CPU-A;
5520 * @pending_disable = -1;
5523 * perf_event_disable_inatomic()
5524 * @pending_disable = CPU-B;
5525 * irq_work_queue(); // FAILS
5528 * perf_pending_event()
5530 * But the event runs on CPU-B and wants disabling there.
5532 irq_work_queue_on(&event
->pending
, cpu
);
5535 static void perf_pending_event(struct irq_work
*entry
)
5537 struct perf_event
*event
= container_of(entry
, struct perf_event
, pending
);
5540 rctx
= perf_swevent_get_recursion_context();
5542 * If we 'fail' here, that's OK, it means recursion is already disabled
5543 * and we won't recurse 'further'.
5546 perf_pending_event_disable(event
);
5548 if (event
->pending_wakeup
) {
5549 event
->pending_wakeup
= 0;
5550 perf_event_wakeup(event
);
5554 perf_swevent_put_recursion_context(rctx
);
5558 * We assume there is only KVM supporting the callbacks.
5559 * Later on, we might change it to a list if there is
5560 * another virtualization implementation supporting the callbacks.
5562 struct perf_guest_info_callbacks
*perf_guest_cbs
;
5564 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
5566 perf_guest_cbs
= cbs
;
5569 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks
);
5571 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
5573 perf_guest_cbs
= NULL
;
5576 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks
);
5579 perf_output_sample_regs(struct perf_output_handle
*handle
,
5580 struct pt_regs
*regs
, u64 mask
)
5583 DECLARE_BITMAP(_mask
, 64);
5585 bitmap_from_u64(_mask
, mask
);
5586 for_each_set_bit(bit
, _mask
, sizeof(mask
) * BITS_PER_BYTE
) {
5589 val
= perf_reg_value(regs
, bit
);
5590 perf_output_put(handle
, val
);
5594 static void perf_sample_regs_user(struct perf_regs
*regs_user
,
5595 struct pt_regs
*regs
,
5596 struct pt_regs
*regs_user_copy
)
5598 if (user_mode(regs
)) {
5599 regs_user
->abi
= perf_reg_abi(current
);
5600 regs_user
->regs
= regs
;
5601 } else if (!(current
->flags
& PF_KTHREAD
)) {
5602 perf_get_regs_user(regs_user
, regs
, regs_user_copy
);
5604 regs_user
->abi
= PERF_SAMPLE_REGS_ABI_NONE
;
5605 regs_user
->regs
= NULL
;
5609 static void perf_sample_regs_intr(struct perf_regs
*regs_intr
,
5610 struct pt_regs
*regs
)
5612 regs_intr
->regs
= regs
;
5613 regs_intr
->abi
= perf_reg_abi(current
);
5618 * Get remaining task size from user stack pointer.
5620 * It'd be better to take stack vma map and limit this more
5621 * precisly, but there's no way to get it safely under interrupt,
5622 * so using TASK_SIZE as limit.
5624 static u64
perf_ustack_task_size(struct pt_regs
*regs
)
5626 unsigned long addr
= perf_user_stack_pointer(regs
);
5628 if (!addr
|| addr
>= TASK_SIZE
)
5631 return TASK_SIZE
- addr
;
5635 perf_sample_ustack_size(u16 stack_size
, u16 header_size
,
5636 struct pt_regs
*regs
)
5640 /* No regs, no stack pointer, no dump. */
5645 * Check if we fit in with the requested stack size into the:
5647 * If we don't, we limit the size to the TASK_SIZE.
5649 * - remaining sample size
5650 * If we don't, we customize the stack size to
5651 * fit in to the remaining sample size.
5654 task_size
= min((u64
) USHRT_MAX
, perf_ustack_task_size(regs
));
5655 stack_size
= min(stack_size
, (u16
) task_size
);
5657 /* Current header size plus static size and dynamic size. */
5658 header_size
+= 2 * sizeof(u64
);
5660 /* Do we fit in with the current stack dump size? */
5661 if ((u16
) (header_size
+ stack_size
) < header_size
) {
5663 * If we overflow the maximum size for the sample,
5664 * we customize the stack dump size to fit in.
5666 stack_size
= USHRT_MAX
- header_size
- sizeof(u64
);
5667 stack_size
= round_up(stack_size
, sizeof(u64
));
5674 perf_output_sample_ustack(struct perf_output_handle
*handle
, u64 dump_size
,
5675 struct pt_regs
*regs
)
5677 /* Case of a kernel thread, nothing to dump */
5680 perf_output_put(handle
, size
);
5690 * - the size requested by user or the best one we can fit
5691 * in to the sample max size
5693 * - user stack dump data
5695 * - the actual dumped size
5699 perf_output_put(handle
, dump_size
);
5702 sp
= perf_user_stack_pointer(regs
);
5705 rem
= __output_copy_user(handle
, (void *) sp
, dump_size
);
5707 dyn_size
= dump_size
- rem
;
5709 perf_output_skip(handle
, rem
);
5712 perf_output_put(handle
, dyn_size
);
5716 static void __perf_event_header__init_id(struct perf_event_header
*header
,
5717 struct perf_sample_data
*data
,
5718 struct perf_event
*event
)
5720 u64 sample_type
= event
->attr
.sample_type
;
5722 data
->type
= sample_type
;
5723 header
->size
+= event
->id_header_size
;
5725 if (sample_type
& PERF_SAMPLE_TID
) {
5726 /* namespace issues */
5727 data
->tid_entry
.pid
= perf_event_pid(event
, current
);
5728 data
->tid_entry
.tid
= perf_event_tid(event
, current
);
5731 if (sample_type
& PERF_SAMPLE_TIME
)
5732 data
->time
= perf_event_clock(event
);
5734 if (sample_type
& (PERF_SAMPLE_ID
| PERF_SAMPLE_IDENTIFIER
))
5735 data
->id
= primary_event_id(event
);
5737 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
5738 data
->stream_id
= event
->id
;
5740 if (sample_type
& PERF_SAMPLE_CPU
) {
5741 data
->cpu_entry
.cpu
= raw_smp_processor_id();
5742 data
->cpu_entry
.reserved
= 0;
5746 void perf_event_header__init_id(struct perf_event_header
*header
,
5747 struct perf_sample_data
*data
,
5748 struct perf_event
*event
)
5750 if (event
->attr
.sample_id_all
)
5751 __perf_event_header__init_id(header
, data
, event
);
5754 static void __perf_event__output_id_sample(struct perf_output_handle
*handle
,
5755 struct perf_sample_data
*data
)
5757 u64 sample_type
= data
->type
;
5759 if (sample_type
& PERF_SAMPLE_TID
)
5760 perf_output_put(handle
, data
->tid_entry
);
5762 if (sample_type
& PERF_SAMPLE_TIME
)
5763 perf_output_put(handle
, data
->time
);
5765 if (sample_type
& PERF_SAMPLE_ID
)
5766 perf_output_put(handle
, data
->id
);
5768 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
5769 perf_output_put(handle
, data
->stream_id
);
5771 if (sample_type
& PERF_SAMPLE_CPU
)
5772 perf_output_put(handle
, data
->cpu_entry
);
5774 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
5775 perf_output_put(handle
, data
->id
);
5778 void perf_event__output_id_sample(struct perf_event
*event
,
5779 struct perf_output_handle
*handle
,
5780 struct perf_sample_data
*sample
)
5782 if (event
->attr
.sample_id_all
)
5783 __perf_event__output_id_sample(handle
, sample
);
5786 static void perf_output_read_one(struct perf_output_handle
*handle
,
5787 struct perf_event
*event
,
5788 u64 enabled
, u64 running
)
5790 u64 read_format
= event
->attr
.read_format
;
5794 values
[n
++] = perf_event_count(event
);
5795 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
5796 values
[n
++] = enabled
+
5797 atomic64_read(&event
->child_total_time_enabled
);
5799 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
5800 values
[n
++] = running
+
5801 atomic64_read(&event
->child_total_time_running
);
5803 if (read_format
& PERF_FORMAT_ID
)
5804 values
[n
++] = primary_event_id(event
);
5806 __output_copy(handle
, values
, n
* sizeof(u64
));
5809 static void perf_output_read_group(struct perf_output_handle
*handle
,
5810 struct perf_event
*event
,
5811 u64 enabled
, u64 running
)
5813 struct perf_event
*leader
= event
->group_leader
, *sub
;
5814 u64 read_format
= event
->attr
.read_format
;
5818 values
[n
++] = 1 + leader
->nr_siblings
;
5820 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
5821 values
[n
++] = enabled
;
5823 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
5824 values
[n
++] = running
;
5826 if ((leader
!= event
) &&
5827 (leader
->state
== PERF_EVENT_STATE_ACTIVE
))
5828 leader
->pmu
->read(leader
);
5830 values
[n
++] = perf_event_count(leader
);
5831 if (read_format
& PERF_FORMAT_ID
)
5832 values
[n
++] = primary_event_id(leader
);
5834 __output_copy(handle
, values
, n
* sizeof(u64
));
5836 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
5839 if ((sub
!= event
) &&
5840 (sub
->state
== PERF_EVENT_STATE_ACTIVE
))
5841 sub
->pmu
->read(sub
);
5843 values
[n
++] = perf_event_count(sub
);
5844 if (read_format
& PERF_FORMAT_ID
)
5845 values
[n
++] = primary_event_id(sub
);
5847 __output_copy(handle
, values
, n
* sizeof(u64
));
5851 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5852 PERF_FORMAT_TOTAL_TIME_RUNNING)
5855 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
5857 * The problem is that its both hard and excessively expensive to iterate the
5858 * child list, not to mention that its impossible to IPI the children running
5859 * on another CPU, from interrupt/NMI context.
5861 static void perf_output_read(struct perf_output_handle
*handle
,
5862 struct perf_event
*event
)
5864 u64 enabled
= 0, running
= 0, now
;
5865 u64 read_format
= event
->attr
.read_format
;
5868 * compute total_time_enabled, total_time_running
5869 * based on snapshot values taken when the event
5870 * was last scheduled in.
5872 * we cannot simply called update_context_time()
5873 * because of locking issue as we are called in
5876 if (read_format
& PERF_FORMAT_TOTAL_TIMES
)
5877 calc_timer_values(event
, &now
, &enabled
, &running
);
5879 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
)
5880 perf_output_read_group(handle
, event
, enabled
, running
);
5882 perf_output_read_one(handle
, event
, enabled
, running
);
5885 void perf_output_sample(struct perf_output_handle
*handle
,
5886 struct perf_event_header
*header
,
5887 struct perf_sample_data
*data
,
5888 struct perf_event
*event
)
5890 u64 sample_type
= data
->type
;
5892 perf_output_put(handle
, *header
);
5894 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
5895 perf_output_put(handle
, data
->id
);
5897 if (sample_type
& PERF_SAMPLE_IP
)
5898 perf_output_put(handle
, data
->ip
);
5900 if (sample_type
& PERF_SAMPLE_TID
)
5901 perf_output_put(handle
, data
->tid_entry
);
5903 if (sample_type
& PERF_SAMPLE_TIME
)
5904 perf_output_put(handle
, data
->time
);
5906 if (sample_type
& PERF_SAMPLE_ADDR
)
5907 perf_output_put(handle
, data
->addr
);
5909 if (sample_type
& PERF_SAMPLE_ID
)
5910 perf_output_put(handle
, data
->id
);
5912 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
5913 perf_output_put(handle
, data
->stream_id
);
5915 if (sample_type
& PERF_SAMPLE_CPU
)
5916 perf_output_put(handle
, data
->cpu_entry
);
5918 if (sample_type
& PERF_SAMPLE_PERIOD
)
5919 perf_output_put(handle
, data
->period
);
5921 if (sample_type
& PERF_SAMPLE_READ
)
5922 perf_output_read(handle
, event
);
5924 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
5925 if (data
->callchain
) {
5928 if (data
->callchain
)
5929 size
+= data
->callchain
->nr
;
5931 size
*= sizeof(u64
);
5933 __output_copy(handle
, data
->callchain
, size
);
5936 perf_output_put(handle
, nr
);
5940 if (sample_type
& PERF_SAMPLE_RAW
) {
5941 struct perf_raw_record
*raw
= data
->raw
;
5944 struct perf_raw_frag
*frag
= &raw
->frag
;
5946 perf_output_put(handle
, raw
->size
);
5949 __output_custom(handle
, frag
->copy
,
5950 frag
->data
, frag
->size
);
5952 __output_copy(handle
, frag
->data
,
5955 if (perf_raw_frag_last(frag
))
5960 __output_skip(handle
, NULL
, frag
->pad
);
5966 .size
= sizeof(u32
),
5969 perf_output_put(handle
, raw
);
5973 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
5974 if (data
->br_stack
) {
5977 size
= data
->br_stack
->nr
5978 * sizeof(struct perf_branch_entry
);
5980 perf_output_put(handle
, data
->br_stack
->nr
);
5981 perf_output_copy(handle
, data
->br_stack
->entries
, size
);
5984 * we always store at least the value of nr
5987 perf_output_put(handle
, nr
);
5991 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
5992 u64 abi
= data
->regs_user
.abi
;
5995 * If there are no regs to dump, notice it through
5996 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5998 perf_output_put(handle
, abi
);
6001 u64 mask
= event
->attr
.sample_regs_user
;
6002 perf_output_sample_regs(handle
,
6003 data
->regs_user
.regs
,
6008 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
6009 perf_output_sample_ustack(handle
,
6010 data
->stack_user_size
,
6011 data
->regs_user
.regs
);
6014 if (sample_type
& PERF_SAMPLE_WEIGHT
)
6015 perf_output_put(handle
, data
->weight
);
6017 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
6018 perf_output_put(handle
, data
->data_src
.val
);
6020 if (sample_type
& PERF_SAMPLE_TRANSACTION
)
6021 perf_output_put(handle
, data
->txn
);
6023 if (sample_type
& PERF_SAMPLE_REGS_INTR
) {
6024 u64 abi
= data
->regs_intr
.abi
;
6026 * If there are no regs to dump, notice it through
6027 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6029 perf_output_put(handle
, abi
);
6032 u64 mask
= event
->attr
.sample_regs_intr
;
6034 perf_output_sample_regs(handle
,
6035 data
->regs_intr
.regs
,
6040 if (sample_type
& PERF_SAMPLE_PHYS_ADDR
)
6041 perf_output_put(handle
, data
->phys_addr
);
6043 if (!event
->attr
.watermark
) {
6044 int wakeup_events
= event
->attr
.wakeup_events
;
6046 if (wakeup_events
) {
6047 struct ring_buffer
*rb
= handle
->rb
;
6048 int events
= local_inc_return(&rb
->events
);
6050 if (events
>= wakeup_events
) {
6051 local_sub(wakeup_events
, &rb
->events
);
6052 local_inc(&rb
->wakeup
);
6058 static u64
perf_virt_to_phys(u64 virt
)
6061 struct page
*p
= NULL
;
6066 if (virt
>= TASK_SIZE
) {
6067 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6068 if (virt_addr_valid((void *)(uintptr_t)virt
) &&
6069 !(virt
>= VMALLOC_START
&& virt
< VMALLOC_END
))
6070 phys_addr
= (u64
)virt_to_phys((void *)(uintptr_t)virt
);
6073 * Walking the pages tables for user address.
6074 * Interrupts are disabled, so it prevents any tear down
6075 * of the page tables.
6076 * Try IRQ-safe __get_user_pages_fast first.
6077 * If failed, leave phys_addr as 0.
6079 if ((current
->mm
!= NULL
) &&
6080 (__get_user_pages_fast(virt
, 1, 0, &p
) == 1))
6081 phys_addr
= page_to_phys(p
) + virt
% PAGE_SIZE
;
6090 void perf_prepare_sample(struct perf_event_header
*header
,
6091 struct perf_sample_data
*data
,
6092 struct perf_event
*event
,
6093 struct pt_regs
*regs
)
6095 u64 sample_type
= event
->attr
.sample_type
;
6097 header
->type
= PERF_RECORD_SAMPLE
;
6098 header
->size
= sizeof(*header
) + event
->header_size
;
6101 header
->misc
|= perf_misc_flags(regs
);
6103 __perf_event_header__init_id(header
, data
, event
);
6105 if (sample_type
& PERF_SAMPLE_IP
)
6106 data
->ip
= perf_instruction_pointer(regs
);
6108 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
6111 data
->callchain
= perf_callchain(event
, regs
);
6113 if (data
->callchain
)
6114 size
+= data
->callchain
->nr
;
6116 header
->size
+= size
* sizeof(u64
);
6119 if (sample_type
& PERF_SAMPLE_RAW
) {
6120 struct perf_raw_record
*raw
= data
->raw
;
6124 struct perf_raw_frag
*frag
= &raw
->frag
;
6129 if (perf_raw_frag_last(frag
))
6134 size
= round_up(sum
+ sizeof(u32
), sizeof(u64
));
6135 raw
->size
= size
- sizeof(u32
);
6136 frag
->pad
= raw
->size
- sum
;
6141 header
->size
+= size
;
6144 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
6145 int size
= sizeof(u64
); /* nr */
6146 if (data
->br_stack
) {
6147 size
+= data
->br_stack
->nr
6148 * sizeof(struct perf_branch_entry
);
6150 header
->size
+= size
;
6153 if (sample_type
& (PERF_SAMPLE_REGS_USER
| PERF_SAMPLE_STACK_USER
))
6154 perf_sample_regs_user(&data
->regs_user
, regs
,
6155 &data
->regs_user_copy
);
6157 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
6158 /* regs dump ABI info */
6159 int size
= sizeof(u64
);
6161 if (data
->regs_user
.regs
) {
6162 u64 mask
= event
->attr
.sample_regs_user
;
6163 size
+= hweight64(mask
) * sizeof(u64
);
6166 header
->size
+= size
;
6169 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
6171 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6172 * processed as the last one or have additional check added
6173 * in case new sample type is added, because we could eat
6174 * up the rest of the sample size.
6176 u16 stack_size
= event
->attr
.sample_stack_user
;
6177 u16 size
= sizeof(u64
);
6179 stack_size
= perf_sample_ustack_size(stack_size
, header
->size
,
6180 data
->regs_user
.regs
);
6183 * If there is something to dump, add space for the dump
6184 * itself and for the field that tells the dynamic size,
6185 * which is how many have been actually dumped.
6188 size
+= sizeof(u64
) + stack_size
;
6190 data
->stack_user_size
= stack_size
;
6191 header
->size
+= size
;
6194 if (sample_type
& PERF_SAMPLE_REGS_INTR
) {
6195 /* regs dump ABI info */
6196 int size
= sizeof(u64
);
6198 perf_sample_regs_intr(&data
->regs_intr
, regs
);
6200 if (data
->regs_intr
.regs
) {
6201 u64 mask
= event
->attr
.sample_regs_intr
;
6203 size
+= hweight64(mask
) * sizeof(u64
);
6206 header
->size
+= size
;
6209 if (sample_type
& PERF_SAMPLE_PHYS_ADDR
)
6210 data
->phys_addr
= perf_virt_to_phys(data
->addr
);
6213 static void __always_inline
6214 __perf_event_output(struct perf_event
*event
,
6215 struct perf_sample_data
*data
,
6216 struct pt_regs
*regs
,
6217 int (*output_begin
)(struct perf_output_handle
*,
6218 struct perf_event
*,
6221 struct perf_output_handle handle
;
6222 struct perf_event_header header
;
6224 /* protect the callchain buffers */
6227 perf_prepare_sample(&header
, data
, event
, regs
);
6229 if (output_begin(&handle
, event
, header
.size
))
6232 perf_output_sample(&handle
, &header
, data
, event
);
6234 perf_output_end(&handle
);
6241 perf_event_output_forward(struct perf_event
*event
,
6242 struct perf_sample_data
*data
,
6243 struct pt_regs
*regs
)
6245 __perf_event_output(event
, data
, regs
, perf_output_begin_forward
);
6249 perf_event_output_backward(struct perf_event
*event
,
6250 struct perf_sample_data
*data
,
6251 struct pt_regs
*regs
)
6253 __perf_event_output(event
, data
, regs
, perf_output_begin_backward
);
6257 perf_event_output(struct perf_event
*event
,
6258 struct perf_sample_data
*data
,
6259 struct pt_regs
*regs
)
6261 __perf_event_output(event
, data
, regs
, perf_output_begin
);
6268 struct perf_read_event
{
6269 struct perf_event_header header
;
6276 perf_event_read_event(struct perf_event
*event
,
6277 struct task_struct
*task
)
6279 struct perf_output_handle handle
;
6280 struct perf_sample_data sample
;
6281 struct perf_read_event read_event
= {
6283 .type
= PERF_RECORD_READ
,
6285 .size
= sizeof(read_event
) + event
->read_size
,
6287 .pid
= perf_event_pid(event
, task
),
6288 .tid
= perf_event_tid(event
, task
),
6292 perf_event_header__init_id(&read_event
.header
, &sample
, event
);
6293 ret
= perf_output_begin(&handle
, event
, read_event
.header
.size
);
6297 perf_output_put(&handle
, read_event
);
6298 perf_output_read(&handle
, event
);
6299 perf_event__output_id_sample(event
, &handle
, &sample
);
6301 perf_output_end(&handle
);
6304 typedef void (perf_iterate_f
)(struct perf_event
*event
, void *data
);
6307 perf_iterate_ctx(struct perf_event_context
*ctx
,
6308 perf_iterate_f output
,
6309 void *data
, bool all
)
6311 struct perf_event
*event
;
6313 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
6315 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
6317 if (!event_filter_match(event
))
6321 output(event
, data
);
6325 static void perf_iterate_sb_cpu(perf_iterate_f output
, void *data
)
6327 struct pmu_event_list
*pel
= this_cpu_ptr(&pmu_sb_events
);
6328 struct perf_event
*event
;
6330 list_for_each_entry_rcu(event
, &pel
->list
, sb_list
) {
6332 * Skip events that are not fully formed yet; ensure that
6333 * if we observe event->ctx, both event and ctx will be
6334 * complete enough. See perf_install_in_context().
6336 if (!smp_load_acquire(&event
->ctx
))
6339 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
6341 if (!event_filter_match(event
))
6343 output(event
, data
);
6348 * Iterate all events that need to receive side-band events.
6350 * For new callers; ensure that account_pmu_sb_event() includes
6351 * your event, otherwise it might not get delivered.
6354 perf_iterate_sb(perf_iterate_f output
, void *data
,
6355 struct perf_event_context
*task_ctx
)
6357 struct perf_event_context
*ctx
;
6364 * If we have task_ctx != NULL we only notify the task context itself.
6365 * The task_ctx is set only for EXIT events before releasing task
6369 perf_iterate_ctx(task_ctx
, output
, data
, false);
6373 perf_iterate_sb_cpu(output
, data
);
6375 for_each_task_context_nr(ctxn
) {
6376 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
6378 perf_iterate_ctx(ctx
, output
, data
, false);
6386 * Clear all file-based filters at exec, they'll have to be
6387 * re-instated when/if these objects are mmapped again.
6389 static void perf_event_addr_filters_exec(struct perf_event
*event
, void *data
)
6391 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
6392 struct perf_addr_filter
*filter
;
6393 unsigned int restart
= 0, count
= 0;
6394 unsigned long flags
;
6396 if (!has_addr_filter(event
))
6399 raw_spin_lock_irqsave(&ifh
->lock
, flags
);
6400 list_for_each_entry(filter
, &ifh
->list
, entry
) {
6401 if (filter
->inode
) {
6402 event
->addr_filters_offs
[count
] = 0;
6410 event
->addr_filters_gen
++;
6411 raw_spin_unlock_irqrestore(&ifh
->lock
, flags
);
6414 perf_event_stop(event
, 1);
6417 void perf_event_exec(void)
6419 struct perf_event_context
*ctx
;
6423 for_each_task_context_nr(ctxn
) {
6424 ctx
= current
->perf_event_ctxp
[ctxn
];
6428 perf_event_enable_on_exec(ctxn
);
6430 perf_iterate_ctx(ctx
, perf_event_addr_filters_exec
, NULL
,
6436 struct remote_output
{
6437 struct ring_buffer
*rb
;
6441 static void __perf_event_output_stop(struct perf_event
*event
, void *data
)
6443 struct perf_event
*parent
= event
->parent
;
6444 struct remote_output
*ro
= data
;
6445 struct ring_buffer
*rb
= ro
->rb
;
6446 struct stop_event_data sd
= {
6450 if (!has_aux(event
))
6457 * In case of inheritance, it will be the parent that links to the
6458 * ring-buffer, but it will be the child that's actually using it.
6460 * We are using event::rb to determine if the event should be stopped,
6461 * however this may race with ring_buffer_attach() (through set_output),
6462 * which will make us skip the event that actually needs to be stopped.
6463 * So ring_buffer_attach() has to stop an aux event before re-assigning
6466 if (rcu_dereference(parent
->rb
) == rb
)
6467 ro
->err
= __perf_event_stop(&sd
);
6470 static int __perf_pmu_output_stop(void *info
)
6472 struct perf_event
*event
= info
;
6473 struct pmu
*pmu
= event
->ctx
->pmu
;
6474 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
6475 struct remote_output ro
= {
6480 perf_iterate_ctx(&cpuctx
->ctx
, __perf_event_output_stop
, &ro
, false);
6481 if (cpuctx
->task_ctx
)
6482 perf_iterate_ctx(cpuctx
->task_ctx
, __perf_event_output_stop
,
6489 static void perf_pmu_output_stop(struct perf_event
*event
)
6491 struct perf_event
*iter
;
6496 list_for_each_entry_rcu(iter
, &event
->rb
->event_list
, rb_entry
) {
6498 * For per-CPU events, we need to make sure that neither they
6499 * nor their children are running; for cpu==-1 events it's
6500 * sufficient to stop the event itself if it's active, since
6501 * it can't have children.
6505 cpu
= READ_ONCE(iter
->oncpu
);
6510 err
= cpu_function_call(cpu
, __perf_pmu_output_stop
, event
);
6511 if (err
== -EAGAIN
) {
6520 * task tracking -- fork/exit
6522 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6525 struct perf_task_event
{
6526 struct task_struct
*task
;
6527 struct perf_event_context
*task_ctx
;
6530 struct perf_event_header header
;
6540 static int perf_event_task_match(struct perf_event
*event
)
6542 return event
->attr
.comm
|| event
->attr
.mmap
||
6543 event
->attr
.mmap2
|| event
->attr
.mmap_data
||
6547 static void perf_event_task_output(struct perf_event
*event
,
6550 struct perf_task_event
*task_event
= data
;
6551 struct perf_output_handle handle
;
6552 struct perf_sample_data sample
;
6553 struct task_struct
*task
= task_event
->task
;
6554 int ret
, size
= task_event
->event_id
.header
.size
;
6556 if (!perf_event_task_match(event
))
6559 perf_event_header__init_id(&task_event
->event_id
.header
, &sample
, event
);
6561 ret
= perf_output_begin(&handle
, event
,
6562 task_event
->event_id
.header
.size
);
6566 task_event
->event_id
.pid
= perf_event_pid(event
, task
);
6567 task_event
->event_id
.ppid
= perf_event_pid(event
, current
);
6569 task_event
->event_id
.tid
= perf_event_tid(event
, task
);
6570 task_event
->event_id
.ptid
= perf_event_tid(event
, current
);
6572 task_event
->event_id
.time
= perf_event_clock(event
);
6574 perf_output_put(&handle
, task_event
->event_id
);
6576 perf_event__output_id_sample(event
, &handle
, &sample
);
6578 perf_output_end(&handle
);
6580 task_event
->event_id
.header
.size
= size
;
6583 static void perf_event_task(struct task_struct
*task
,
6584 struct perf_event_context
*task_ctx
,
6587 struct perf_task_event task_event
;
6589 if (!atomic_read(&nr_comm_events
) &&
6590 !atomic_read(&nr_mmap_events
) &&
6591 !atomic_read(&nr_task_events
))
6594 task_event
= (struct perf_task_event
){
6596 .task_ctx
= task_ctx
,
6599 .type
= new ? PERF_RECORD_FORK
: PERF_RECORD_EXIT
,
6601 .size
= sizeof(task_event
.event_id
),
6611 perf_iterate_sb(perf_event_task_output
,
6616 void perf_event_fork(struct task_struct
*task
)
6618 perf_event_task(task
, NULL
, 1);
6619 perf_event_namespaces(task
);
6626 struct perf_comm_event
{
6627 struct task_struct
*task
;
6632 struct perf_event_header header
;
6639 static int perf_event_comm_match(struct perf_event
*event
)
6641 return event
->attr
.comm
;
6644 static void perf_event_comm_output(struct perf_event
*event
,
6647 struct perf_comm_event
*comm_event
= data
;
6648 struct perf_output_handle handle
;
6649 struct perf_sample_data sample
;
6650 int size
= comm_event
->event_id
.header
.size
;
6653 if (!perf_event_comm_match(event
))
6656 perf_event_header__init_id(&comm_event
->event_id
.header
, &sample
, event
);
6657 ret
= perf_output_begin(&handle
, event
,
6658 comm_event
->event_id
.header
.size
);
6663 comm_event
->event_id
.pid
= perf_event_pid(event
, comm_event
->task
);
6664 comm_event
->event_id
.tid
= perf_event_tid(event
, comm_event
->task
);
6666 perf_output_put(&handle
, comm_event
->event_id
);
6667 __output_copy(&handle
, comm_event
->comm
,
6668 comm_event
->comm_size
);
6670 perf_event__output_id_sample(event
, &handle
, &sample
);
6672 perf_output_end(&handle
);
6674 comm_event
->event_id
.header
.size
= size
;
6677 static void perf_event_comm_event(struct perf_comm_event
*comm_event
)
6679 char comm
[TASK_COMM_LEN
];
6682 memset(comm
, 0, sizeof(comm
));
6683 strlcpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
6684 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
6686 comm_event
->comm
= comm
;
6687 comm_event
->comm_size
= size
;
6689 comm_event
->event_id
.header
.size
= sizeof(comm_event
->event_id
) + size
;
6691 perf_iterate_sb(perf_event_comm_output
,
6696 void perf_event_comm(struct task_struct
*task
, bool exec
)
6698 struct perf_comm_event comm_event
;
6700 if (!atomic_read(&nr_comm_events
))
6703 comm_event
= (struct perf_comm_event
){
6709 .type
= PERF_RECORD_COMM
,
6710 .misc
= exec
? PERF_RECORD_MISC_COMM_EXEC
: 0,
6718 perf_event_comm_event(&comm_event
);
6722 * namespaces tracking
6725 struct perf_namespaces_event
{
6726 struct task_struct
*task
;
6729 struct perf_event_header header
;
6734 struct perf_ns_link_info link_info
[NR_NAMESPACES
];
6738 static int perf_event_namespaces_match(struct perf_event
*event
)
6740 return event
->attr
.namespaces
;
6743 static void perf_event_namespaces_output(struct perf_event
*event
,
6746 struct perf_namespaces_event
*namespaces_event
= data
;
6747 struct perf_output_handle handle
;
6748 struct perf_sample_data sample
;
6749 u16 header_size
= namespaces_event
->event_id
.header
.size
;
6752 if (!perf_event_namespaces_match(event
))
6755 perf_event_header__init_id(&namespaces_event
->event_id
.header
,
6757 ret
= perf_output_begin(&handle
, event
,
6758 namespaces_event
->event_id
.header
.size
);
6762 namespaces_event
->event_id
.pid
= perf_event_pid(event
,
6763 namespaces_event
->task
);
6764 namespaces_event
->event_id
.tid
= perf_event_tid(event
,
6765 namespaces_event
->task
);
6767 perf_output_put(&handle
, namespaces_event
->event_id
);
6769 perf_event__output_id_sample(event
, &handle
, &sample
);
6771 perf_output_end(&handle
);
6773 namespaces_event
->event_id
.header
.size
= header_size
;
6776 static void perf_fill_ns_link_info(struct perf_ns_link_info
*ns_link_info
,
6777 struct task_struct
*task
,
6778 const struct proc_ns_operations
*ns_ops
)
6780 struct path ns_path
;
6781 struct inode
*ns_inode
;
6784 error
= ns_get_path(&ns_path
, task
, ns_ops
);
6786 ns_inode
= ns_path
.dentry
->d_inode
;
6787 ns_link_info
->dev
= new_encode_dev(ns_inode
->i_sb
->s_dev
);
6788 ns_link_info
->ino
= ns_inode
->i_ino
;
6793 void perf_event_namespaces(struct task_struct
*task
)
6795 struct perf_namespaces_event namespaces_event
;
6796 struct perf_ns_link_info
*ns_link_info
;
6798 if (!atomic_read(&nr_namespaces_events
))
6801 namespaces_event
= (struct perf_namespaces_event
){
6805 .type
= PERF_RECORD_NAMESPACES
,
6807 .size
= sizeof(namespaces_event
.event_id
),
6811 .nr_namespaces
= NR_NAMESPACES
,
6812 /* .link_info[NR_NAMESPACES] */
6816 ns_link_info
= namespaces_event
.event_id
.link_info
;
6818 perf_fill_ns_link_info(&ns_link_info
[MNT_NS_INDEX
],
6819 task
, &mntns_operations
);
6821 #ifdef CONFIG_USER_NS
6822 perf_fill_ns_link_info(&ns_link_info
[USER_NS_INDEX
],
6823 task
, &userns_operations
);
6825 #ifdef CONFIG_NET_NS
6826 perf_fill_ns_link_info(&ns_link_info
[NET_NS_INDEX
],
6827 task
, &netns_operations
);
6829 #ifdef CONFIG_UTS_NS
6830 perf_fill_ns_link_info(&ns_link_info
[UTS_NS_INDEX
],
6831 task
, &utsns_operations
);
6833 #ifdef CONFIG_IPC_NS
6834 perf_fill_ns_link_info(&ns_link_info
[IPC_NS_INDEX
],
6835 task
, &ipcns_operations
);
6837 #ifdef CONFIG_PID_NS
6838 perf_fill_ns_link_info(&ns_link_info
[PID_NS_INDEX
],
6839 task
, &pidns_operations
);
6841 #ifdef CONFIG_CGROUPS
6842 perf_fill_ns_link_info(&ns_link_info
[CGROUP_NS_INDEX
],
6843 task
, &cgroupns_operations
);
6846 perf_iterate_sb(perf_event_namespaces_output
,
6855 struct perf_mmap_event
{
6856 struct vm_area_struct
*vma
;
6858 const char *file_name
;
6866 struct perf_event_header header
;
6876 static int perf_event_mmap_match(struct perf_event
*event
,
6879 struct perf_mmap_event
*mmap_event
= data
;
6880 struct vm_area_struct
*vma
= mmap_event
->vma
;
6881 int executable
= vma
->vm_flags
& VM_EXEC
;
6883 return (!executable
&& event
->attr
.mmap_data
) ||
6884 (executable
&& (event
->attr
.mmap
|| event
->attr
.mmap2
));
6887 static void perf_event_mmap_output(struct perf_event
*event
,
6890 struct perf_mmap_event
*mmap_event
= data
;
6891 struct perf_output_handle handle
;
6892 struct perf_sample_data sample
;
6893 int size
= mmap_event
->event_id
.header
.size
;
6894 u32 type
= mmap_event
->event_id
.header
.type
;
6897 if (!perf_event_mmap_match(event
, data
))
6900 if (event
->attr
.mmap2
) {
6901 mmap_event
->event_id
.header
.type
= PERF_RECORD_MMAP2
;
6902 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->maj
);
6903 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->min
);
6904 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->ino
);
6905 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->ino_generation
);
6906 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->prot
);
6907 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->flags
);
6910 perf_event_header__init_id(&mmap_event
->event_id
.header
, &sample
, event
);
6911 ret
= perf_output_begin(&handle
, event
,
6912 mmap_event
->event_id
.header
.size
);
6916 mmap_event
->event_id
.pid
= perf_event_pid(event
, current
);
6917 mmap_event
->event_id
.tid
= perf_event_tid(event
, current
);
6919 perf_output_put(&handle
, mmap_event
->event_id
);
6921 if (event
->attr
.mmap2
) {
6922 perf_output_put(&handle
, mmap_event
->maj
);
6923 perf_output_put(&handle
, mmap_event
->min
);
6924 perf_output_put(&handle
, mmap_event
->ino
);
6925 perf_output_put(&handle
, mmap_event
->ino_generation
);
6926 perf_output_put(&handle
, mmap_event
->prot
);
6927 perf_output_put(&handle
, mmap_event
->flags
);
6930 __output_copy(&handle
, mmap_event
->file_name
,
6931 mmap_event
->file_size
);
6933 perf_event__output_id_sample(event
, &handle
, &sample
);
6935 perf_output_end(&handle
);
6937 mmap_event
->event_id
.header
.size
= size
;
6938 mmap_event
->event_id
.header
.type
= type
;
6941 static void perf_event_mmap_event(struct perf_mmap_event
*mmap_event
)
6943 struct vm_area_struct
*vma
= mmap_event
->vma
;
6944 struct file
*file
= vma
->vm_file
;
6945 int maj
= 0, min
= 0;
6946 u64 ino
= 0, gen
= 0;
6947 u32 prot
= 0, flags
= 0;
6953 if (vma
->vm_flags
& VM_READ
)
6955 if (vma
->vm_flags
& VM_WRITE
)
6957 if (vma
->vm_flags
& VM_EXEC
)
6960 if (vma
->vm_flags
& VM_MAYSHARE
)
6963 flags
= MAP_PRIVATE
;
6965 if (vma
->vm_flags
& VM_DENYWRITE
)
6966 flags
|= MAP_DENYWRITE
;
6967 if (vma
->vm_flags
& VM_MAYEXEC
)
6968 flags
|= MAP_EXECUTABLE
;
6969 if (vma
->vm_flags
& VM_LOCKED
)
6970 flags
|= MAP_LOCKED
;
6971 if (vma
->vm_flags
& VM_HUGETLB
)
6972 flags
|= MAP_HUGETLB
;
6975 struct inode
*inode
;
6978 buf
= kmalloc(PATH_MAX
, GFP_KERNEL
);
6984 * d_path() works from the end of the rb backwards, so we
6985 * need to add enough zero bytes after the string to handle
6986 * the 64bit alignment we do later.
6988 name
= file_path(file
, buf
, PATH_MAX
- sizeof(u64
));
6993 inode
= file_inode(vma
->vm_file
);
6994 dev
= inode
->i_sb
->s_dev
;
6996 gen
= inode
->i_generation
;
7002 if (vma
->vm_ops
&& vma
->vm_ops
->name
) {
7003 name
= (char *) vma
->vm_ops
->name(vma
);
7008 name
= (char *)arch_vma_name(vma
);
7012 if (vma
->vm_start
<= vma
->vm_mm
->start_brk
&&
7013 vma
->vm_end
>= vma
->vm_mm
->brk
) {
7017 if (vma
->vm_start
<= vma
->vm_mm
->start_stack
&&
7018 vma
->vm_end
>= vma
->vm_mm
->start_stack
) {
7028 strlcpy(tmp
, name
, sizeof(tmp
));
7032 * Since our buffer works in 8 byte units we need to align our string
7033 * size to a multiple of 8. However, we must guarantee the tail end is
7034 * zero'd out to avoid leaking random bits to userspace.
7036 size
= strlen(name
)+1;
7037 while (!IS_ALIGNED(size
, sizeof(u64
)))
7038 name
[size
++] = '\0';
7040 mmap_event
->file_name
= name
;
7041 mmap_event
->file_size
= size
;
7042 mmap_event
->maj
= maj
;
7043 mmap_event
->min
= min
;
7044 mmap_event
->ino
= ino
;
7045 mmap_event
->ino_generation
= gen
;
7046 mmap_event
->prot
= prot
;
7047 mmap_event
->flags
= flags
;
7049 if (!(vma
->vm_flags
& VM_EXEC
))
7050 mmap_event
->event_id
.header
.misc
|= PERF_RECORD_MISC_MMAP_DATA
;
7052 mmap_event
->event_id
.header
.size
= sizeof(mmap_event
->event_id
) + size
;
7054 perf_iterate_sb(perf_event_mmap_output
,
7062 * Check whether inode and address range match filter criteria.
7064 static bool perf_addr_filter_match(struct perf_addr_filter
*filter
,
7065 struct file
*file
, unsigned long offset
,
7068 if (filter
->inode
!= file_inode(file
))
7071 if (filter
->offset
> offset
+ size
)
7074 if (filter
->offset
+ filter
->size
< offset
)
7080 static void __perf_addr_filters_adjust(struct perf_event
*event
, void *data
)
7082 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
7083 struct vm_area_struct
*vma
= data
;
7084 unsigned long off
= vma
->vm_pgoff
<< PAGE_SHIFT
, flags
;
7085 struct file
*file
= vma
->vm_file
;
7086 struct perf_addr_filter
*filter
;
7087 unsigned int restart
= 0, count
= 0;
7089 if (!has_addr_filter(event
))
7095 raw_spin_lock_irqsave(&ifh
->lock
, flags
);
7096 list_for_each_entry(filter
, &ifh
->list
, entry
) {
7097 if (perf_addr_filter_match(filter
, file
, off
,
7098 vma
->vm_end
- vma
->vm_start
)) {
7099 event
->addr_filters_offs
[count
] = vma
->vm_start
;
7107 event
->addr_filters_gen
++;
7108 raw_spin_unlock_irqrestore(&ifh
->lock
, flags
);
7111 perf_event_stop(event
, 1);
7115 * Adjust all task's events' filters to the new vma
7117 static void perf_addr_filters_adjust(struct vm_area_struct
*vma
)
7119 struct perf_event_context
*ctx
;
7123 * Data tracing isn't supported yet and as such there is no need
7124 * to keep track of anything that isn't related to executable code:
7126 if (!(vma
->vm_flags
& VM_EXEC
))
7130 for_each_task_context_nr(ctxn
) {
7131 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
7135 perf_iterate_ctx(ctx
, __perf_addr_filters_adjust
, vma
, true);
7140 void perf_event_mmap(struct vm_area_struct
*vma
)
7142 struct perf_mmap_event mmap_event
;
7144 if (!atomic_read(&nr_mmap_events
))
7147 mmap_event
= (struct perf_mmap_event
){
7153 .type
= PERF_RECORD_MMAP
,
7154 .misc
= PERF_RECORD_MISC_USER
,
7159 .start
= vma
->vm_start
,
7160 .len
= vma
->vm_end
- vma
->vm_start
,
7161 .pgoff
= (u64
)vma
->vm_pgoff
<< PAGE_SHIFT
,
7163 /* .maj (attr_mmap2 only) */
7164 /* .min (attr_mmap2 only) */
7165 /* .ino (attr_mmap2 only) */
7166 /* .ino_generation (attr_mmap2 only) */
7167 /* .prot (attr_mmap2 only) */
7168 /* .flags (attr_mmap2 only) */
7171 perf_addr_filters_adjust(vma
);
7172 perf_event_mmap_event(&mmap_event
);
7175 void perf_event_aux_event(struct perf_event
*event
, unsigned long head
,
7176 unsigned long size
, u64 flags
)
7178 struct perf_output_handle handle
;
7179 struct perf_sample_data sample
;
7180 struct perf_aux_event
{
7181 struct perf_event_header header
;
7187 .type
= PERF_RECORD_AUX
,
7189 .size
= sizeof(rec
),
7197 perf_event_header__init_id(&rec
.header
, &sample
, event
);
7198 ret
= perf_output_begin(&handle
, event
, rec
.header
.size
);
7203 perf_output_put(&handle
, rec
);
7204 perf_event__output_id_sample(event
, &handle
, &sample
);
7206 perf_output_end(&handle
);
7210 * Lost/dropped samples logging
7212 void perf_log_lost_samples(struct perf_event
*event
, u64 lost
)
7214 struct perf_output_handle handle
;
7215 struct perf_sample_data sample
;
7219 struct perf_event_header header
;
7221 } lost_samples_event
= {
7223 .type
= PERF_RECORD_LOST_SAMPLES
,
7225 .size
= sizeof(lost_samples_event
),
7230 perf_event_header__init_id(&lost_samples_event
.header
, &sample
, event
);
7232 ret
= perf_output_begin(&handle
, event
,
7233 lost_samples_event
.header
.size
);
7237 perf_output_put(&handle
, lost_samples_event
);
7238 perf_event__output_id_sample(event
, &handle
, &sample
);
7239 perf_output_end(&handle
);
7243 * context_switch tracking
7246 struct perf_switch_event
{
7247 struct task_struct
*task
;
7248 struct task_struct
*next_prev
;
7251 struct perf_event_header header
;
7257 static int perf_event_switch_match(struct perf_event
*event
)
7259 return event
->attr
.context_switch
;
7262 static void perf_event_switch_output(struct perf_event
*event
, void *data
)
7264 struct perf_switch_event
*se
= data
;
7265 struct perf_output_handle handle
;
7266 struct perf_sample_data sample
;
7269 if (!perf_event_switch_match(event
))
7272 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7273 if (event
->ctx
->task
) {
7274 se
->event_id
.header
.type
= PERF_RECORD_SWITCH
;
7275 se
->event_id
.header
.size
= sizeof(se
->event_id
.header
);
7277 se
->event_id
.header
.type
= PERF_RECORD_SWITCH_CPU_WIDE
;
7278 se
->event_id
.header
.size
= sizeof(se
->event_id
);
7279 se
->event_id
.next_prev_pid
=
7280 perf_event_pid(event
, se
->next_prev
);
7281 se
->event_id
.next_prev_tid
=
7282 perf_event_tid(event
, se
->next_prev
);
7285 perf_event_header__init_id(&se
->event_id
.header
, &sample
, event
);
7287 ret
= perf_output_begin(&handle
, event
, se
->event_id
.header
.size
);
7291 if (event
->ctx
->task
)
7292 perf_output_put(&handle
, se
->event_id
.header
);
7294 perf_output_put(&handle
, se
->event_id
);
7296 perf_event__output_id_sample(event
, &handle
, &sample
);
7298 perf_output_end(&handle
);
7301 static void perf_event_switch(struct task_struct
*task
,
7302 struct task_struct
*next_prev
, bool sched_in
)
7304 struct perf_switch_event switch_event
;
7306 /* N.B. caller checks nr_switch_events != 0 */
7308 switch_event
= (struct perf_switch_event
){
7310 .next_prev
= next_prev
,
7314 .misc
= sched_in
? 0 : PERF_RECORD_MISC_SWITCH_OUT
,
7317 /* .next_prev_pid */
7318 /* .next_prev_tid */
7322 perf_iterate_sb(perf_event_switch_output
,
7328 * IRQ throttle logging
7331 static void perf_log_throttle(struct perf_event
*event
, int enable
)
7333 struct perf_output_handle handle
;
7334 struct perf_sample_data sample
;
7338 struct perf_event_header header
;
7342 } throttle_event
= {
7344 .type
= PERF_RECORD_THROTTLE
,
7346 .size
= sizeof(throttle_event
),
7348 .time
= perf_event_clock(event
),
7349 .id
= primary_event_id(event
),
7350 .stream_id
= event
->id
,
7354 throttle_event
.header
.type
= PERF_RECORD_UNTHROTTLE
;
7356 perf_event_header__init_id(&throttle_event
.header
, &sample
, event
);
7358 ret
= perf_output_begin(&handle
, event
,
7359 throttle_event
.header
.size
);
7363 perf_output_put(&handle
, throttle_event
);
7364 perf_event__output_id_sample(event
, &handle
, &sample
);
7365 perf_output_end(&handle
);
7368 void perf_event_itrace_started(struct perf_event
*event
)
7370 event
->attach_state
|= PERF_ATTACH_ITRACE
;
7373 static void perf_log_itrace_start(struct perf_event
*event
)
7375 struct perf_output_handle handle
;
7376 struct perf_sample_data sample
;
7377 struct perf_aux_event
{
7378 struct perf_event_header header
;
7385 event
= event
->parent
;
7387 if (!(event
->pmu
->capabilities
& PERF_PMU_CAP_ITRACE
) ||
7388 event
->attach_state
& PERF_ATTACH_ITRACE
)
7391 rec
.header
.type
= PERF_RECORD_ITRACE_START
;
7392 rec
.header
.misc
= 0;
7393 rec
.header
.size
= sizeof(rec
);
7394 rec
.pid
= perf_event_pid(event
, current
);
7395 rec
.tid
= perf_event_tid(event
, current
);
7397 perf_event_header__init_id(&rec
.header
, &sample
, event
);
7398 ret
= perf_output_begin(&handle
, event
, rec
.header
.size
);
7403 perf_output_put(&handle
, rec
);
7404 perf_event__output_id_sample(event
, &handle
, &sample
);
7406 perf_output_end(&handle
);
7410 __perf_event_account_interrupt(struct perf_event
*event
, int throttle
)
7412 struct hw_perf_event
*hwc
= &event
->hw
;
7416 seq
= __this_cpu_read(perf_throttled_seq
);
7417 if (seq
!= hwc
->interrupts_seq
) {
7418 hwc
->interrupts_seq
= seq
;
7419 hwc
->interrupts
= 1;
7422 if (unlikely(throttle
7423 && hwc
->interrupts
>= max_samples_per_tick
)) {
7424 __this_cpu_inc(perf_throttled_count
);
7425 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS
);
7426 hwc
->interrupts
= MAX_INTERRUPTS
;
7427 perf_log_throttle(event
, 0);
7432 if (event
->attr
.freq
) {
7433 u64 now
= perf_clock();
7434 s64 delta
= now
- hwc
->freq_time_stamp
;
7436 hwc
->freq_time_stamp
= now
;
7438 if (delta
> 0 && delta
< 2*TICK_NSEC
)
7439 perf_adjust_period(event
, delta
, hwc
->last_period
, true);
7445 int perf_event_account_interrupt(struct perf_event
*event
)
7447 return __perf_event_account_interrupt(event
, 1);
7451 * Generic event overflow handling, sampling.
7454 static int __perf_event_overflow(struct perf_event
*event
,
7455 int throttle
, struct perf_sample_data
*data
,
7456 struct pt_regs
*regs
)
7458 int events
= atomic_read(&event
->event_limit
);
7462 * Non-sampling counters might still use the PMI to fold short
7463 * hardware counters, ignore those.
7465 if (unlikely(!is_sampling_event(event
)))
7468 ret
= __perf_event_account_interrupt(event
, throttle
);
7471 * XXX event_limit might not quite work as expected on inherited
7475 event
->pending_kill
= POLL_IN
;
7476 if (events
&& atomic_dec_and_test(&event
->event_limit
)) {
7478 event
->pending_kill
= POLL_HUP
;
7480 perf_event_disable_inatomic(event
);
7483 READ_ONCE(event
->overflow_handler
)(event
, data
, regs
);
7485 if (*perf_event_fasync(event
) && event
->pending_kill
) {
7486 event
->pending_wakeup
= 1;
7487 irq_work_queue(&event
->pending
);
7493 int perf_event_overflow(struct perf_event
*event
,
7494 struct perf_sample_data
*data
,
7495 struct pt_regs
*regs
)
7497 return __perf_event_overflow(event
, 1, data
, regs
);
7501 * Generic software event infrastructure
7504 struct swevent_htable
{
7505 struct swevent_hlist
*swevent_hlist
;
7506 struct mutex hlist_mutex
;
7509 /* Recursion avoidance in each contexts */
7510 int recursion
[PERF_NR_CONTEXTS
];
7513 static DEFINE_PER_CPU(struct swevent_htable
, swevent_htable
);
7516 * We directly increment event->count and keep a second value in
7517 * event->hw.period_left to count intervals. This period event
7518 * is kept in the range [-sample_period, 0] so that we can use the
7522 u64
perf_swevent_set_period(struct perf_event
*event
)
7524 struct hw_perf_event
*hwc
= &event
->hw
;
7525 u64 period
= hwc
->last_period
;
7529 hwc
->last_period
= hwc
->sample_period
;
7532 old
= val
= local64_read(&hwc
->period_left
);
7536 nr
= div64_u64(period
+ val
, period
);
7537 offset
= nr
* period
;
7539 if (local64_cmpxchg(&hwc
->period_left
, old
, val
) != old
)
7545 static void perf_swevent_overflow(struct perf_event
*event
, u64 overflow
,
7546 struct perf_sample_data
*data
,
7547 struct pt_regs
*regs
)
7549 struct hw_perf_event
*hwc
= &event
->hw
;
7553 overflow
= perf_swevent_set_period(event
);
7555 if (hwc
->interrupts
== MAX_INTERRUPTS
)
7558 for (; overflow
; overflow
--) {
7559 if (__perf_event_overflow(event
, throttle
,
7562 * We inhibit the overflow from happening when
7563 * hwc->interrupts == MAX_INTERRUPTS.
7571 static void perf_swevent_event(struct perf_event
*event
, u64 nr
,
7572 struct perf_sample_data
*data
,
7573 struct pt_regs
*regs
)
7575 struct hw_perf_event
*hwc
= &event
->hw
;
7577 local64_add(nr
, &event
->count
);
7582 if (!is_sampling_event(event
))
7585 if ((event
->attr
.sample_type
& PERF_SAMPLE_PERIOD
) && !event
->attr
.freq
) {
7587 return perf_swevent_overflow(event
, 1, data
, regs
);
7589 data
->period
= event
->hw
.last_period
;
7591 if (nr
== 1 && hwc
->sample_period
== 1 && !event
->attr
.freq
)
7592 return perf_swevent_overflow(event
, 1, data
, regs
);
7594 if (local64_add_negative(nr
, &hwc
->period_left
))
7597 perf_swevent_overflow(event
, 0, data
, regs
);
7600 static int perf_exclude_event(struct perf_event
*event
,
7601 struct pt_regs
*regs
)
7603 if (event
->hw
.state
& PERF_HES_STOPPED
)
7607 if (event
->attr
.exclude_user
&& user_mode(regs
))
7610 if (event
->attr
.exclude_kernel
&& !user_mode(regs
))
7617 static int perf_swevent_match(struct perf_event
*event
,
7618 enum perf_type_id type
,
7620 struct perf_sample_data
*data
,
7621 struct pt_regs
*regs
)
7623 if (event
->attr
.type
!= type
)
7626 if (event
->attr
.config
!= event_id
)
7629 if (perf_exclude_event(event
, regs
))
7635 static inline u64
swevent_hash(u64 type
, u32 event_id
)
7637 u64 val
= event_id
| (type
<< 32);
7639 return hash_64(val
, SWEVENT_HLIST_BITS
);
7642 static inline struct hlist_head
*
7643 __find_swevent_head(struct swevent_hlist
*hlist
, u64 type
, u32 event_id
)
7645 u64 hash
= swevent_hash(type
, event_id
);
7647 return &hlist
->heads
[hash
];
7650 /* For the read side: events when they trigger */
7651 static inline struct hlist_head
*
7652 find_swevent_head_rcu(struct swevent_htable
*swhash
, u64 type
, u32 event_id
)
7654 struct swevent_hlist
*hlist
;
7656 hlist
= rcu_dereference(swhash
->swevent_hlist
);
7660 return __find_swevent_head(hlist
, type
, event_id
);
7663 /* For the event head insertion and removal in the hlist */
7664 static inline struct hlist_head
*
7665 find_swevent_head(struct swevent_htable
*swhash
, struct perf_event
*event
)
7667 struct swevent_hlist
*hlist
;
7668 u32 event_id
= event
->attr
.config
;
7669 u64 type
= event
->attr
.type
;
7672 * Event scheduling is always serialized against hlist allocation
7673 * and release. Which makes the protected version suitable here.
7674 * The context lock guarantees that.
7676 hlist
= rcu_dereference_protected(swhash
->swevent_hlist
,
7677 lockdep_is_held(&event
->ctx
->lock
));
7681 return __find_swevent_head(hlist
, type
, event_id
);
7684 static void do_perf_sw_event(enum perf_type_id type
, u32 event_id
,
7686 struct perf_sample_data
*data
,
7687 struct pt_regs
*regs
)
7689 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7690 struct perf_event
*event
;
7691 struct hlist_head
*head
;
7694 head
= find_swevent_head_rcu(swhash
, type
, event_id
);
7698 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
7699 if (perf_swevent_match(event
, type
, event_id
, data
, regs
))
7700 perf_swevent_event(event
, nr
, data
, regs
);
7706 DEFINE_PER_CPU(struct pt_regs
, __perf_regs
[4]);
7708 int perf_swevent_get_recursion_context(void)
7710 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7712 return get_recursion_context(swhash
->recursion
);
7714 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context
);
7716 void perf_swevent_put_recursion_context(int rctx
)
7718 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7720 put_recursion_context(swhash
->recursion
, rctx
);
7723 void ___perf_sw_event(u32 event_id
, u64 nr
, struct pt_regs
*regs
, u64 addr
)
7725 struct perf_sample_data data
;
7727 if (WARN_ON_ONCE(!regs
))
7730 perf_sample_data_init(&data
, addr
, 0);
7731 do_perf_sw_event(PERF_TYPE_SOFTWARE
, event_id
, nr
, &data
, regs
);
7734 void __perf_sw_event(u32 event_id
, u64 nr
, struct pt_regs
*regs
, u64 addr
)
7738 preempt_disable_notrace();
7739 rctx
= perf_swevent_get_recursion_context();
7740 if (unlikely(rctx
< 0))
7743 ___perf_sw_event(event_id
, nr
, regs
, addr
);
7745 perf_swevent_put_recursion_context(rctx
);
7747 preempt_enable_notrace();
7750 static void perf_swevent_read(struct perf_event
*event
)
7754 static int perf_swevent_add(struct perf_event
*event
, int flags
)
7756 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7757 struct hw_perf_event
*hwc
= &event
->hw
;
7758 struct hlist_head
*head
;
7760 if (is_sampling_event(event
)) {
7761 hwc
->last_period
= hwc
->sample_period
;
7762 perf_swevent_set_period(event
);
7765 hwc
->state
= !(flags
& PERF_EF_START
);
7767 head
= find_swevent_head(swhash
, event
);
7768 if (WARN_ON_ONCE(!head
))
7771 hlist_add_head_rcu(&event
->hlist_entry
, head
);
7772 perf_event_update_userpage(event
);
7777 static void perf_swevent_del(struct perf_event
*event
, int flags
)
7779 hlist_del_rcu(&event
->hlist_entry
);
7782 static void perf_swevent_start(struct perf_event
*event
, int flags
)
7784 event
->hw
.state
= 0;
7787 static void perf_swevent_stop(struct perf_event
*event
, int flags
)
7789 event
->hw
.state
= PERF_HES_STOPPED
;
7792 /* Deref the hlist from the update side */
7793 static inline struct swevent_hlist
*
7794 swevent_hlist_deref(struct swevent_htable
*swhash
)
7796 return rcu_dereference_protected(swhash
->swevent_hlist
,
7797 lockdep_is_held(&swhash
->hlist_mutex
));
7800 static void swevent_hlist_release(struct swevent_htable
*swhash
)
7802 struct swevent_hlist
*hlist
= swevent_hlist_deref(swhash
);
7807 RCU_INIT_POINTER(swhash
->swevent_hlist
, NULL
);
7808 kfree_rcu(hlist
, rcu_head
);
7811 static void swevent_hlist_put_cpu(int cpu
)
7813 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
7815 mutex_lock(&swhash
->hlist_mutex
);
7817 if (!--swhash
->hlist_refcount
)
7818 swevent_hlist_release(swhash
);
7820 mutex_unlock(&swhash
->hlist_mutex
);
7823 static void swevent_hlist_put(void)
7827 for_each_possible_cpu(cpu
)
7828 swevent_hlist_put_cpu(cpu
);
7831 static int swevent_hlist_get_cpu(int cpu
)
7833 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
7836 mutex_lock(&swhash
->hlist_mutex
);
7837 if (!swevent_hlist_deref(swhash
) &&
7838 cpumask_test_cpu(cpu
, perf_online_mask
)) {
7839 struct swevent_hlist
*hlist
;
7841 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
7846 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
7848 swhash
->hlist_refcount
++;
7850 mutex_unlock(&swhash
->hlist_mutex
);
7855 static int swevent_hlist_get(void)
7857 int err
, cpu
, failed_cpu
;
7859 mutex_lock(&pmus_lock
);
7860 for_each_possible_cpu(cpu
) {
7861 err
= swevent_hlist_get_cpu(cpu
);
7867 mutex_unlock(&pmus_lock
);
7870 for_each_possible_cpu(cpu
) {
7871 if (cpu
== failed_cpu
)
7873 swevent_hlist_put_cpu(cpu
);
7875 mutex_unlock(&pmus_lock
);
7879 struct static_key perf_swevent_enabled
[PERF_COUNT_SW_MAX
];
7881 static void sw_perf_event_destroy(struct perf_event
*event
)
7883 u64 event_id
= event
->attr
.config
;
7885 WARN_ON(event
->parent
);
7887 static_key_slow_dec(&perf_swevent_enabled
[event_id
]);
7888 swevent_hlist_put();
7891 static int perf_swevent_init(struct perf_event
*event
)
7893 u64 event_id
= event
->attr
.config
;
7895 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
7899 * no branch sampling for software events
7901 if (has_branch_stack(event
))
7905 case PERF_COUNT_SW_CPU_CLOCK
:
7906 case PERF_COUNT_SW_TASK_CLOCK
:
7913 if (event_id
>= PERF_COUNT_SW_MAX
)
7916 if (!event
->parent
) {
7919 err
= swevent_hlist_get();
7923 static_key_slow_inc(&perf_swevent_enabled
[event_id
]);
7924 event
->destroy
= sw_perf_event_destroy
;
7930 static struct pmu perf_swevent
= {
7931 .task_ctx_nr
= perf_sw_context
,
7933 .capabilities
= PERF_PMU_CAP_NO_NMI
,
7935 .event_init
= perf_swevent_init
,
7936 .add
= perf_swevent_add
,
7937 .del
= perf_swevent_del
,
7938 .start
= perf_swevent_start
,
7939 .stop
= perf_swevent_stop
,
7940 .read
= perf_swevent_read
,
7943 #ifdef CONFIG_EVENT_TRACING
7945 static int perf_tp_filter_match(struct perf_event
*event
,
7946 struct perf_sample_data
*data
)
7948 void *record
= data
->raw
->frag
.data
;
7950 /* only top level events have filters set */
7952 event
= event
->parent
;
7954 if (likely(!event
->filter
) || filter_match_preds(event
->filter
, record
))
7959 static int perf_tp_event_match(struct perf_event
*event
,
7960 struct perf_sample_data
*data
,
7961 struct pt_regs
*regs
)
7963 if (event
->hw
.state
& PERF_HES_STOPPED
)
7966 * All tracepoints are from kernel-space.
7968 if (event
->attr
.exclude_kernel
)
7971 if (!perf_tp_filter_match(event
, data
))
7977 void perf_trace_run_bpf_submit(void *raw_data
, int size
, int rctx
,
7978 struct trace_event_call
*call
, u64 count
,
7979 struct pt_regs
*regs
, struct hlist_head
*head
,
7980 struct task_struct
*task
)
7982 if (bpf_prog_array_valid(call
)) {
7983 *(struct pt_regs
**)raw_data
= regs
;
7984 if (!trace_call_bpf(call
, raw_data
) || hlist_empty(head
)) {
7985 perf_swevent_put_recursion_context(rctx
);
7989 perf_tp_event(call
->event
.type
, count
, raw_data
, size
, regs
, head
,
7992 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit
);
7994 void perf_tp_event(u16 event_type
, u64 count
, void *record
, int entry_size
,
7995 struct pt_regs
*regs
, struct hlist_head
*head
, int rctx
,
7996 struct task_struct
*task
)
7998 struct perf_sample_data data
;
7999 struct perf_event
*event
;
8001 struct perf_raw_record raw
= {
8008 perf_sample_data_init(&data
, 0, 0);
8011 perf_trace_buf_update(record
, event_type
);
8013 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
8014 if (perf_tp_event_match(event
, &data
, regs
))
8015 perf_swevent_event(event
, count
, &data
, regs
);
8019 * If we got specified a target task, also iterate its context and
8020 * deliver this event there too.
8022 if (task
&& task
!= current
) {
8023 struct perf_event_context
*ctx
;
8024 struct trace_entry
*entry
= record
;
8027 ctx
= rcu_dereference(task
->perf_event_ctxp
[perf_sw_context
]);
8031 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
8032 if (event
->cpu
!= smp_processor_id())
8034 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
8036 if (event
->attr
.config
!= entry
->type
)
8038 if (perf_tp_event_match(event
, &data
, regs
))
8039 perf_swevent_event(event
, count
, &data
, regs
);
8045 perf_swevent_put_recursion_context(rctx
);
8047 EXPORT_SYMBOL_GPL(perf_tp_event
);
8049 static void tp_perf_event_destroy(struct perf_event
*event
)
8051 perf_trace_destroy(event
);
8054 static int perf_tp_event_init(struct perf_event
*event
)
8058 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
8062 * no branch sampling for tracepoint events
8064 if (has_branch_stack(event
))
8067 err
= perf_trace_init(event
);
8071 event
->destroy
= tp_perf_event_destroy
;
8076 static struct pmu perf_tracepoint
= {
8077 .task_ctx_nr
= perf_sw_context
,
8079 .event_init
= perf_tp_event_init
,
8080 .add
= perf_trace_add
,
8081 .del
= perf_trace_del
,
8082 .start
= perf_swevent_start
,
8083 .stop
= perf_swevent_stop
,
8084 .read
= perf_swevent_read
,
8087 static inline void perf_tp_register(void)
8089 perf_pmu_register(&perf_tracepoint
, "tracepoint", PERF_TYPE_TRACEPOINT
);
8092 static void perf_event_free_filter(struct perf_event
*event
)
8094 ftrace_profile_free_filter(event
);
8097 #ifdef CONFIG_BPF_SYSCALL
8098 static void bpf_overflow_handler(struct perf_event
*event
,
8099 struct perf_sample_data
*data
,
8100 struct pt_regs
*regs
)
8102 struct bpf_perf_event_data_kern ctx
= {
8108 ctx
.regs
= perf_arch_bpf_user_pt_regs(regs
);
8110 if (unlikely(__this_cpu_inc_return(bpf_prog_active
) != 1))
8113 ret
= BPF_PROG_RUN(event
->prog
, &ctx
);
8116 __this_cpu_dec(bpf_prog_active
);
8121 event
->orig_overflow_handler(event
, data
, regs
);
8124 static int perf_event_set_bpf_handler(struct perf_event
*event
, u32 prog_fd
)
8126 struct bpf_prog
*prog
;
8128 if (event
->overflow_handler_context
)
8129 /* hw breakpoint or kernel counter */
8135 prog
= bpf_prog_get_type(prog_fd
, BPF_PROG_TYPE_PERF_EVENT
);
8137 return PTR_ERR(prog
);
8140 event
->orig_overflow_handler
= READ_ONCE(event
->overflow_handler
);
8141 WRITE_ONCE(event
->overflow_handler
, bpf_overflow_handler
);
8145 static void perf_event_free_bpf_handler(struct perf_event
*event
)
8147 struct bpf_prog
*prog
= event
->prog
;
8152 WRITE_ONCE(event
->overflow_handler
, event
->orig_overflow_handler
);
8157 static int perf_event_set_bpf_handler(struct perf_event
*event
, u32 prog_fd
)
8161 static void perf_event_free_bpf_handler(struct perf_event
*event
)
8166 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
)
8168 bool is_kprobe
, is_tracepoint
, is_syscall_tp
;
8169 struct bpf_prog
*prog
;
8172 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
8173 return perf_event_set_bpf_handler(event
, prog_fd
);
8175 is_kprobe
= event
->tp_event
->flags
& TRACE_EVENT_FL_UKPROBE
;
8176 is_tracepoint
= event
->tp_event
->flags
& TRACE_EVENT_FL_TRACEPOINT
;
8177 is_syscall_tp
= is_syscall_trace_event(event
->tp_event
);
8178 if (!is_kprobe
&& !is_tracepoint
&& !is_syscall_tp
)
8179 /* bpf programs can only be attached to u/kprobe or tracepoint */
8182 prog
= bpf_prog_get(prog_fd
);
8184 return PTR_ERR(prog
);
8186 if ((is_kprobe
&& prog
->type
!= BPF_PROG_TYPE_KPROBE
) ||
8187 (is_tracepoint
&& prog
->type
!= BPF_PROG_TYPE_TRACEPOINT
) ||
8188 (is_syscall_tp
&& prog
->type
!= BPF_PROG_TYPE_TRACEPOINT
)) {
8189 /* valid fd, but invalid bpf program type */
8194 if (is_tracepoint
|| is_syscall_tp
) {
8195 int off
= trace_event_get_offsets(event
->tp_event
);
8197 if (prog
->aux
->max_ctx_offset
> off
) {
8203 ret
= perf_event_attach_bpf_prog(event
, prog
);
8209 static void perf_event_free_bpf_prog(struct perf_event
*event
)
8211 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
) {
8212 perf_event_free_bpf_handler(event
);
8215 perf_event_detach_bpf_prog(event
);
8220 static inline void perf_tp_register(void)
8224 static void perf_event_free_filter(struct perf_event
*event
)
8228 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
)
8233 static void perf_event_free_bpf_prog(struct perf_event
*event
)
8236 #endif /* CONFIG_EVENT_TRACING */
8238 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8239 void perf_bp_event(struct perf_event
*bp
, void *data
)
8241 struct perf_sample_data sample
;
8242 struct pt_regs
*regs
= data
;
8244 perf_sample_data_init(&sample
, bp
->attr
.bp_addr
, 0);
8246 if (!bp
->hw
.state
&& !perf_exclude_event(bp
, regs
))
8247 perf_swevent_event(bp
, 1, &sample
, regs
);
8252 * Allocate a new address filter
8254 static struct perf_addr_filter
*
8255 perf_addr_filter_new(struct perf_event
*event
, struct list_head
*filters
)
8257 int node
= cpu_to_node(event
->cpu
== -1 ? 0 : event
->cpu
);
8258 struct perf_addr_filter
*filter
;
8260 filter
= kzalloc_node(sizeof(*filter
), GFP_KERNEL
, node
);
8264 INIT_LIST_HEAD(&filter
->entry
);
8265 list_add_tail(&filter
->entry
, filters
);
8270 static void free_filters_list(struct list_head
*filters
)
8272 struct perf_addr_filter
*filter
, *iter
;
8274 list_for_each_entry_safe(filter
, iter
, filters
, entry
) {
8276 iput(filter
->inode
);
8277 list_del(&filter
->entry
);
8283 * Free existing address filters and optionally install new ones
8285 static void perf_addr_filters_splice(struct perf_event
*event
,
8286 struct list_head
*head
)
8288 unsigned long flags
;
8291 if (!has_addr_filter(event
))
8294 /* don't bother with children, they don't have their own filters */
8298 raw_spin_lock_irqsave(&event
->addr_filters
.lock
, flags
);
8300 list_splice_init(&event
->addr_filters
.list
, &list
);
8302 list_splice(head
, &event
->addr_filters
.list
);
8304 raw_spin_unlock_irqrestore(&event
->addr_filters
.lock
, flags
);
8306 free_filters_list(&list
);
8310 * Scan through mm's vmas and see if one of them matches the
8311 * @filter; if so, adjust filter's address range.
8312 * Called with mm::mmap_sem down for reading.
8314 static unsigned long perf_addr_filter_apply(struct perf_addr_filter
*filter
,
8315 struct mm_struct
*mm
)
8317 struct vm_area_struct
*vma
;
8319 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
8320 struct file
*file
= vma
->vm_file
;
8321 unsigned long off
= vma
->vm_pgoff
<< PAGE_SHIFT
;
8322 unsigned long vma_size
= vma
->vm_end
- vma
->vm_start
;
8327 if (!perf_addr_filter_match(filter
, file
, off
, vma_size
))
8330 return vma
->vm_start
;
8337 * Update event's address range filters based on the
8338 * task's existing mappings, if any.
8340 static void perf_event_addr_filters_apply(struct perf_event
*event
)
8342 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
8343 struct task_struct
*task
= READ_ONCE(event
->ctx
->task
);
8344 struct perf_addr_filter
*filter
;
8345 struct mm_struct
*mm
= NULL
;
8346 unsigned int count
= 0;
8347 unsigned long flags
;
8350 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8351 * will stop on the parent's child_mutex that our caller is also holding
8353 if (task
== TASK_TOMBSTONE
)
8356 if (!ifh
->nr_file_filters
)
8359 mm
= get_task_mm(event
->ctx
->task
);
8363 down_read(&mm
->mmap_sem
);
8365 raw_spin_lock_irqsave(&ifh
->lock
, flags
);
8366 list_for_each_entry(filter
, &ifh
->list
, entry
) {
8367 event
->addr_filters_offs
[count
] = 0;
8370 * Adjust base offset if the filter is associated to a binary
8371 * that needs to be mapped:
8374 event
->addr_filters_offs
[count
] =
8375 perf_addr_filter_apply(filter
, mm
);
8380 event
->addr_filters_gen
++;
8381 raw_spin_unlock_irqrestore(&ifh
->lock
, flags
);
8383 up_read(&mm
->mmap_sem
);
8388 perf_event_stop(event
, 1);
8392 * Address range filtering: limiting the data to certain
8393 * instruction address ranges. Filters are ioctl()ed to us from
8394 * userspace as ascii strings.
8396 * Filter string format:
8399 * where ACTION is one of the
8400 * * "filter": limit the trace to this region
8401 * * "start": start tracing from this address
8402 * * "stop": stop tracing at this address/region;
8404 * * for kernel addresses: <start address>[/<size>]
8405 * * for object files: <start address>[/<size>]@</path/to/object/file>
8407 * if <size> is not specified, the range is treated as a single address.
8421 IF_STATE_ACTION
= 0,
8426 static const match_table_t if_tokens
= {
8427 { IF_ACT_FILTER
, "filter" },
8428 { IF_ACT_START
, "start" },
8429 { IF_ACT_STOP
, "stop" },
8430 { IF_SRC_FILE
, "%u/%u@%s" },
8431 { IF_SRC_KERNEL
, "%u/%u" },
8432 { IF_SRC_FILEADDR
, "%u@%s" },
8433 { IF_SRC_KERNELADDR
, "%u" },
8434 { IF_ACT_NONE
, NULL
},
8438 * Address filter string parser
8441 perf_event_parse_addr_filter(struct perf_event
*event
, char *fstr
,
8442 struct list_head
*filters
)
8444 struct perf_addr_filter
*filter
= NULL
;
8445 char *start
, *orig
, *filename
= NULL
;
8447 substring_t args
[MAX_OPT_ARGS
];
8448 int state
= IF_STATE_ACTION
, token
;
8449 unsigned int kernel
= 0;
8452 orig
= fstr
= kstrdup(fstr
, GFP_KERNEL
);
8456 while ((start
= strsep(&fstr
, " ,\n")) != NULL
) {
8462 /* filter definition begins */
8463 if (state
== IF_STATE_ACTION
) {
8464 filter
= perf_addr_filter_new(event
, filters
);
8469 token
= match_token(start
, if_tokens
, args
);
8476 if (state
!= IF_STATE_ACTION
)
8479 state
= IF_STATE_SOURCE
;
8482 case IF_SRC_KERNELADDR
:
8486 case IF_SRC_FILEADDR
:
8488 if (state
!= IF_STATE_SOURCE
)
8491 if (token
== IF_SRC_FILE
|| token
== IF_SRC_KERNEL
)
8495 ret
= kstrtoul(args
[0].from
, 0, &filter
->offset
);
8499 if (filter
->range
) {
8501 ret
= kstrtoul(args
[1].from
, 0, &filter
->size
);
8506 if (token
== IF_SRC_FILE
|| token
== IF_SRC_FILEADDR
) {
8507 int fpos
= filter
->range
? 2 : 1;
8509 filename
= match_strdup(&args
[fpos
]);
8516 state
= IF_STATE_END
;
8524 * Filter definition is fully parsed, validate and install it.
8525 * Make sure that it doesn't contradict itself or the event's
8528 if (state
== IF_STATE_END
) {
8530 if (kernel
&& event
->attr
.exclude_kernel
)
8538 * For now, we only support file-based filters
8539 * in per-task events; doing so for CPU-wide
8540 * events requires additional context switching
8541 * trickery, since same object code will be
8542 * mapped at different virtual addresses in
8543 * different processes.
8546 if (!event
->ctx
->task
)
8547 goto fail_free_name
;
8549 /* look up the path and grab its inode */
8550 ret
= kern_path(filename
, LOOKUP_FOLLOW
, &path
);
8552 goto fail_free_name
;
8554 filter
->inode
= igrab(d_inode(path
.dentry
));
8560 if (!filter
->inode
||
8561 !S_ISREG(filter
->inode
->i_mode
))
8562 /* free_filters_list() will iput() */
8565 event
->addr_filters
.nr_file_filters
++;
8568 /* ready to consume more filters */
8569 state
= IF_STATE_ACTION
;
8574 if (state
!= IF_STATE_ACTION
)
8584 free_filters_list(filters
);
8591 perf_event_set_addr_filter(struct perf_event
*event
, char *filter_str
)
8597 * Since this is called in perf_ioctl() path, we're already holding
8600 lockdep_assert_held(&event
->ctx
->mutex
);
8602 if (WARN_ON_ONCE(event
->parent
))
8605 ret
= perf_event_parse_addr_filter(event
, filter_str
, &filters
);
8607 goto fail_clear_files
;
8609 ret
= event
->pmu
->addr_filters_validate(&filters
);
8611 goto fail_free_filters
;
8613 /* remove existing filters, if any */
8614 perf_addr_filters_splice(event
, &filters
);
8616 /* install new filters */
8617 perf_event_for_each_child(event
, perf_event_addr_filters_apply
);
8622 free_filters_list(&filters
);
8625 event
->addr_filters
.nr_file_filters
= 0;
8631 perf_tracepoint_set_filter(struct perf_event
*event
, char *filter_str
)
8633 struct perf_event_context
*ctx
= event
->ctx
;
8637 * Beware, here be dragons!!
8639 * the tracepoint muck will deadlock against ctx->mutex, but the tracepoint
8640 * stuff does not actually need it. So temporarily drop ctx->mutex. As per
8641 * perf_event_ctx_lock() we already have a reference on ctx.
8643 * This can result in event getting moved to a different ctx, but that
8644 * does not affect the tracepoint state.
8646 mutex_unlock(&ctx
->mutex
);
8647 ret
= ftrace_profile_set_filter(event
, event
->attr
.config
, filter_str
);
8648 mutex_lock(&ctx
->mutex
);
8653 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
8658 if ((event
->attr
.type
!= PERF_TYPE_TRACEPOINT
||
8659 !IS_ENABLED(CONFIG_EVENT_TRACING
)) &&
8660 !has_addr_filter(event
))
8663 filter_str
= strndup_user(arg
, PAGE_SIZE
);
8664 if (IS_ERR(filter_str
))
8665 return PTR_ERR(filter_str
);
8667 if (IS_ENABLED(CONFIG_EVENT_TRACING
) &&
8668 event
->attr
.type
== PERF_TYPE_TRACEPOINT
)
8669 ret
= perf_tracepoint_set_filter(event
, filter_str
);
8670 else if (has_addr_filter(event
))
8671 ret
= perf_event_set_addr_filter(event
, filter_str
);
8678 * hrtimer based swevent callback
8681 static enum hrtimer_restart
perf_swevent_hrtimer(struct hrtimer
*hrtimer
)
8683 enum hrtimer_restart ret
= HRTIMER_RESTART
;
8684 struct perf_sample_data data
;
8685 struct pt_regs
*regs
;
8686 struct perf_event
*event
;
8689 event
= container_of(hrtimer
, struct perf_event
, hw
.hrtimer
);
8691 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
8692 return HRTIMER_NORESTART
;
8694 event
->pmu
->read(event
);
8696 perf_sample_data_init(&data
, 0, event
->hw
.last_period
);
8697 regs
= get_irq_regs();
8699 if (regs
&& !perf_exclude_event(event
, regs
)) {
8700 if (!(event
->attr
.exclude_idle
&& is_idle_task(current
)))
8701 if (__perf_event_overflow(event
, 1, &data
, regs
))
8702 ret
= HRTIMER_NORESTART
;
8705 period
= max_t(u64
, 10000, event
->hw
.sample_period
);
8706 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
8711 static void perf_swevent_start_hrtimer(struct perf_event
*event
)
8713 struct hw_perf_event
*hwc
= &event
->hw
;
8716 if (!is_sampling_event(event
))
8719 period
= local64_read(&hwc
->period_left
);
8724 local64_set(&hwc
->period_left
, 0);
8726 period
= max_t(u64
, 10000, hwc
->sample_period
);
8728 hrtimer_start(&hwc
->hrtimer
, ns_to_ktime(period
),
8729 HRTIMER_MODE_REL_PINNED
);
8732 static void perf_swevent_cancel_hrtimer(struct perf_event
*event
)
8734 struct hw_perf_event
*hwc
= &event
->hw
;
8736 if (is_sampling_event(event
)) {
8737 ktime_t remaining
= hrtimer_get_remaining(&hwc
->hrtimer
);
8738 local64_set(&hwc
->period_left
, ktime_to_ns(remaining
));
8740 hrtimer_cancel(&hwc
->hrtimer
);
8744 static void perf_swevent_init_hrtimer(struct perf_event
*event
)
8746 struct hw_perf_event
*hwc
= &event
->hw
;
8748 if (!is_sampling_event(event
))
8751 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
8752 hwc
->hrtimer
.function
= perf_swevent_hrtimer
;
8755 * Since hrtimers have a fixed rate, we can do a static freq->period
8756 * mapping and avoid the whole period adjust feedback stuff.
8758 if (event
->attr
.freq
) {
8759 long freq
= event
->attr
.sample_freq
;
8761 event
->attr
.sample_period
= NSEC_PER_SEC
/ freq
;
8762 hwc
->sample_period
= event
->attr
.sample_period
;
8763 local64_set(&hwc
->period_left
, hwc
->sample_period
);
8764 hwc
->last_period
= hwc
->sample_period
;
8765 event
->attr
.freq
= 0;
8770 * Software event: cpu wall time clock
8773 static void cpu_clock_event_update(struct perf_event
*event
)
8778 now
= local_clock();
8779 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
8780 local64_add(now
- prev
, &event
->count
);
8783 static void cpu_clock_event_start(struct perf_event
*event
, int flags
)
8785 local64_set(&event
->hw
.prev_count
, local_clock());
8786 perf_swevent_start_hrtimer(event
);
8789 static void cpu_clock_event_stop(struct perf_event
*event
, int flags
)
8791 perf_swevent_cancel_hrtimer(event
);
8792 cpu_clock_event_update(event
);
8795 static int cpu_clock_event_add(struct perf_event
*event
, int flags
)
8797 if (flags
& PERF_EF_START
)
8798 cpu_clock_event_start(event
, flags
);
8799 perf_event_update_userpage(event
);
8804 static void cpu_clock_event_del(struct perf_event
*event
, int flags
)
8806 cpu_clock_event_stop(event
, flags
);
8809 static void cpu_clock_event_read(struct perf_event
*event
)
8811 cpu_clock_event_update(event
);
8814 static int cpu_clock_event_init(struct perf_event
*event
)
8816 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
8819 if (event
->attr
.config
!= PERF_COUNT_SW_CPU_CLOCK
)
8823 * no branch sampling for software events
8825 if (has_branch_stack(event
))
8828 perf_swevent_init_hrtimer(event
);
8833 static struct pmu perf_cpu_clock
= {
8834 .task_ctx_nr
= perf_sw_context
,
8836 .capabilities
= PERF_PMU_CAP_NO_NMI
,
8838 .event_init
= cpu_clock_event_init
,
8839 .add
= cpu_clock_event_add
,
8840 .del
= cpu_clock_event_del
,
8841 .start
= cpu_clock_event_start
,
8842 .stop
= cpu_clock_event_stop
,
8843 .read
= cpu_clock_event_read
,
8847 * Software event: task time clock
8850 static void task_clock_event_update(struct perf_event
*event
, u64 now
)
8855 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
8857 local64_add(delta
, &event
->count
);
8860 static void task_clock_event_start(struct perf_event
*event
, int flags
)
8862 local64_set(&event
->hw
.prev_count
, event
->ctx
->time
);
8863 perf_swevent_start_hrtimer(event
);
8866 static void task_clock_event_stop(struct perf_event
*event
, int flags
)
8868 perf_swevent_cancel_hrtimer(event
);
8869 task_clock_event_update(event
, event
->ctx
->time
);
8872 static int task_clock_event_add(struct perf_event
*event
, int flags
)
8874 if (flags
& PERF_EF_START
)
8875 task_clock_event_start(event
, flags
);
8876 perf_event_update_userpage(event
);
8881 static void task_clock_event_del(struct perf_event
*event
, int flags
)
8883 task_clock_event_stop(event
, PERF_EF_UPDATE
);
8886 static void task_clock_event_read(struct perf_event
*event
)
8888 u64 now
= perf_clock();
8889 u64 delta
= now
- event
->ctx
->timestamp
;
8890 u64 time
= event
->ctx
->time
+ delta
;
8892 task_clock_event_update(event
, time
);
8895 static int task_clock_event_init(struct perf_event
*event
)
8897 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
8900 if (event
->attr
.config
!= PERF_COUNT_SW_TASK_CLOCK
)
8904 * no branch sampling for software events
8906 if (has_branch_stack(event
))
8909 perf_swevent_init_hrtimer(event
);
8914 static struct pmu perf_task_clock
= {
8915 .task_ctx_nr
= perf_sw_context
,
8917 .capabilities
= PERF_PMU_CAP_NO_NMI
,
8919 .event_init
= task_clock_event_init
,
8920 .add
= task_clock_event_add
,
8921 .del
= task_clock_event_del
,
8922 .start
= task_clock_event_start
,
8923 .stop
= task_clock_event_stop
,
8924 .read
= task_clock_event_read
,
8927 static void perf_pmu_nop_void(struct pmu
*pmu
)
8931 static void perf_pmu_nop_txn(struct pmu
*pmu
, unsigned int flags
)
8935 static int perf_pmu_nop_int(struct pmu
*pmu
)
8940 static int perf_event_nop_int(struct perf_event
*event
, u64 value
)
8945 static DEFINE_PER_CPU(unsigned int, nop_txn_flags
);
8947 static void perf_pmu_start_txn(struct pmu
*pmu
, unsigned int flags
)
8949 __this_cpu_write(nop_txn_flags
, flags
);
8951 if (flags
& ~PERF_PMU_TXN_ADD
)
8954 perf_pmu_disable(pmu
);
8957 static int perf_pmu_commit_txn(struct pmu
*pmu
)
8959 unsigned int flags
= __this_cpu_read(nop_txn_flags
);
8961 __this_cpu_write(nop_txn_flags
, 0);
8963 if (flags
& ~PERF_PMU_TXN_ADD
)
8966 perf_pmu_enable(pmu
);
8970 static void perf_pmu_cancel_txn(struct pmu
*pmu
)
8972 unsigned int flags
= __this_cpu_read(nop_txn_flags
);
8974 __this_cpu_write(nop_txn_flags
, 0);
8976 if (flags
& ~PERF_PMU_TXN_ADD
)
8979 perf_pmu_enable(pmu
);
8982 static int perf_event_idx_default(struct perf_event
*event
)
8988 * Ensures all contexts with the same task_ctx_nr have the same
8989 * pmu_cpu_context too.
8991 static struct perf_cpu_context __percpu
*find_pmu_context(int ctxn
)
8998 list_for_each_entry(pmu
, &pmus
, entry
) {
8999 if (pmu
->task_ctx_nr
== ctxn
)
9000 return pmu
->pmu_cpu_context
;
9006 static void free_pmu_context(struct pmu
*pmu
)
9009 * Static contexts such as perf_sw_context have a global lifetime
9010 * and may be shared between different PMUs. Avoid freeing them
9011 * when a single PMU is going away.
9013 if (pmu
->task_ctx_nr
> perf_invalid_context
)
9016 free_percpu(pmu
->pmu_cpu_context
);
9020 * Let userspace know that this PMU supports address range filtering:
9022 static ssize_t
nr_addr_filters_show(struct device
*dev
,
9023 struct device_attribute
*attr
,
9026 struct pmu
*pmu
= dev_get_drvdata(dev
);
9028 return snprintf(page
, PAGE_SIZE
- 1, "%d\n", pmu
->nr_addr_filters
);
9030 DEVICE_ATTR_RO(nr_addr_filters
);
9032 static struct idr pmu_idr
;
9035 type_show(struct device
*dev
, struct device_attribute
*attr
, char *page
)
9037 struct pmu
*pmu
= dev_get_drvdata(dev
);
9039 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->type
);
9041 static DEVICE_ATTR_RO(type
);
9044 perf_event_mux_interval_ms_show(struct device
*dev
,
9045 struct device_attribute
*attr
,
9048 struct pmu
*pmu
= dev_get_drvdata(dev
);
9050 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->hrtimer_interval_ms
);
9053 static DEFINE_MUTEX(mux_interval_mutex
);
9056 perf_event_mux_interval_ms_store(struct device
*dev
,
9057 struct device_attribute
*attr
,
9058 const char *buf
, size_t count
)
9060 struct pmu
*pmu
= dev_get_drvdata(dev
);
9061 int timer
, cpu
, ret
;
9063 ret
= kstrtoint(buf
, 0, &timer
);
9070 /* same value, noting to do */
9071 if (timer
== pmu
->hrtimer_interval_ms
)
9074 mutex_lock(&mux_interval_mutex
);
9075 pmu
->hrtimer_interval_ms
= timer
;
9077 /* update all cpuctx for this PMU */
9079 for_each_online_cpu(cpu
) {
9080 struct perf_cpu_context
*cpuctx
;
9081 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
9082 cpuctx
->hrtimer_interval
= ns_to_ktime(NSEC_PER_MSEC
* timer
);
9084 cpu_function_call(cpu
,
9085 (remote_function_f
)perf_mux_hrtimer_restart
, cpuctx
);
9088 mutex_unlock(&mux_interval_mutex
);
9092 static DEVICE_ATTR_RW(perf_event_mux_interval_ms
);
9094 static struct attribute
*pmu_dev_attrs
[] = {
9095 &dev_attr_type
.attr
,
9096 &dev_attr_perf_event_mux_interval_ms
.attr
,
9099 ATTRIBUTE_GROUPS(pmu_dev
);
9101 static int pmu_bus_running
;
9102 static struct bus_type pmu_bus
= {
9103 .name
= "event_source",
9104 .dev_groups
= pmu_dev_groups
,
9107 static void pmu_dev_release(struct device
*dev
)
9112 static int pmu_dev_alloc(struct pmu
*pmu
)
9116 pmu
->dev
= kzalloc(sizeof(struct device
), GFP_KERNEL
);
9120 pmu
->dev
->groups
= pmu
->attr_groups
;
9121 device_initialize(pmu
->dev
);
9122 ret
= dev_set_name(pmu
->dev
, "%s", pmu
->name
);
9126 dev_set_drvdata(pmu
->dev
, pmu
);
9127 pmu
->dev
->bus
= &pmu_bus
;
9128 pmu
->dev
->release
= pmu_dev_release
;
9129 ret
= device_add(pmu
->dev
);
9133 /* For PMUs with address filters, throw in an extra attribute: */
9134 if (pmu
->nr_addr_filters
)
9135 ret
= device_create_file(pmu
->dev
, &dev_attr_nr_addr_filters
);
9144 device_del(pmu
->dev
);
9147 put_device(pmu
->dev
);
9151 static struct lock_class_key cpuctx_mutex
;
9152 static struct lock_class_key cpuctx_lock
;
9154 int perf_pmu_register(struct pmu
*pmu
, const char *name
, int type
)
9158 mutex_lock(&pmus_lock
);
9160 pmu
->pmu_disable_count
= alloc_percpu(int);
9161 if (!pmu
->pmu_disable_count
)
9170 type
= idr_alloc(&pmu_idr
, pmu
, PERF_TYPE_MAX
, 0, GFP_KERNEL
);
9178 if (pmu_bus_running
) {
9179 ret
= pmu_dev_alloc(pmu
);
9185 if (pmu
->task_ctx_nr
== perf_hw_context
) {
9186 static int hw_context_taken
= 0;
9189 * Other than systems with heterogeneous CPUs, it never makes
9190 * sense for two PMUs to share perf_hw_context. PMUs which are
9191 * uncore must use perf_invalid_context.
9193 if (WARN_ON_ONCE(hw_context_taken
&&
9194 !(pmu
->capabilities
& PERF_PMU_CAP_HETEROGENEOUS_CPUS
)))
9195 pmu
->task_ctx_nr
= perf_invalid_context
;
9197 hw_context_taken
= 1;
9200 pmu
->pmu_cpu_context
= find_pmu_context(pmu
->task_ctx_nr
);
9201 if (pmu
->pmu_cpu_context
)
9202 goto got_cpu_context
;
9205 pmu
->pmu_cpu_context
= alloc_percpu(struct perf_cpu_context
);
9206 if (!pmu
->pmu_cpu_context
)
9209 for_each_possible_cpu(cpu
) {
9210 struct perf_cpu_context
*cpuctx
;
9212 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
9213 __perf_event_init_context(&cpuctx
->ctx
);
9214 lockdep_set_class(&cpuctx
->ctx
.mutex
, &cpuctx_mutex
);
9215 lockdep_set_class(&cpuctx
->ctx
.lock
, &cpuctx_lock
);
9216 cpuctx
->ctx
.pmu
= pmu
;
9217 cpuctx
->online
= cpumask_test_cpu(cpu
, perf_online_mask
);
9219 __perf_mux_hrtimer_init(cpuctx
, cpu
);
9223 if (!pmu
->start_txn
) {
9224 if (pmu
->pmu_enable
) {
9226 * If we have pmu_enable/pmu_disable calls, install
9227 * transaction stubs that use that to try and batch
9228 * hardware accesses.
9230 pmu
->start_txn
= perf_pmu_start_txn
;
9231 pmu
->commit_txn
= perf_pmu_commit_txn
;
9232 pmu
->cancel_txn
= perf_pmu_cancel_txn
;
9234 pmu
->start_txn
= perf_pmu_nop_txn
;
9235 pmu
->commit_txn
= perf_pmu_nop_int
;
9236 pmu
->cancel_txn
= perf_pmu_nop_void
;
9240 if (!pmu
->pmu_enable
) {
9241 pmu
->pmu_enable
= perf_pmu_nop_void
;
9242 pmu
->pmu_disable
= perf_pmu_nop_void
;
9245 if (!pmu
->check_period
)
9246 pmu
->check_period
= perf_event_nop_int
;
9248 if (!pmu
->event_idx
)
9249 pmu
->event_idx
= perf_event_idx_default
;
9251 list_add_rcu(&pmu
->entry
, &pmus
);
9252 atomic_set(&pmu
->exclusive_cnt
, 0);
9255 mutex_unlock(&pmus_lock
);
9260 device_del(pmu
->dev
);
9261 put_device(pmu
->dev
);
9264 if (pmu
->type
>= PERF_TYPE_MAX
)
9265 idr_remove(&pmu_idr
, pmu
->type
);
9268 free_percpu(pmu
->pmu_disable_count
);
9271 EXPORT_SYMBOL_GPL(perf_pmu_register
);
9273 void perf_pmu_unregister(struct pmu
*pmu
)
9275 mutex_lock(&pmus_lock
);
9276 list_del_rcu(&pmu
->entry
);
9279 * We dereference the pmu list under both SRCU and regular RCU, so
9280 * synchronize against both of those.
9282 synchronize_srcu(&pmus_srcu
);
9285 free_percpu(pmu
->pmu_disable_count
);
9286 if (pmu
->type
>= PERF_TYPE_MAX
)
9287 idr_remove(&pmu_idr
, pmu
->type
);
9288 if (pmu_bus_running
) {
9289 if (pmu
->nr_addr_filters
)
9290 device_remove_file(pmu
->dev
, &dev_attr_nr_addr_filters
);
9291 device_del(pmu
->dev
);
9292 put_device(pmu
->dev
);
9294 free_pmu_context(pmu
);
9295 mutex_unlock(&pmus_lock
);
9297 EXPORT_SYMBOL_GPL(perf_pmu_unregister
);
9299 static int perf_try_init_event(struct pmu
*pmu
, struct perf_event
*event
)
9301 struct perf_event_context
*ctx
= NULL
;
9304 if (!try_module_get(pmu
->module
))
9308 * A number of pmu->event_init() methods iterate the sibling_list to,
9309 * for example, validate if the group fits on the PMU. Therefore,
9310 * if this is a sibling event, acquire the ctx->mutex to protect
9313 if (event
->group_leader
!= event
&& pmu
->task_ctx_nr
!= perf_sw_context
) {
9315 * This ctx->mutex can nest when we're called through
9316 * inheritance. See the perf_event_ctx_lock_nested() comment.
9318 ctx
= perf_event_ctx_lock_nested(event
->group_leader
,
9319 SINGLE_DEPTH_NESTING
);
9324 ret
= pmu
->event_init(event
);
9327 perf_event_ctx_unlock(event
->group_leader
, ctx
);
9330 module_put(pmu
->module
);
9335 static struct pmu
*perf_init_event(struct perf_event
*event
)
9341 idx
= srcu_read_lock(&pmus_srcu
);
9343 /* Try parent's PMU first: */
9344 if (event
->parent
&& event
->parent
->pmu
) {
9345 pmu
= event
->parent
->pmu
;
9346 ret
= perf_try_init_event(pmu
, event
);
9352 pmu
= idr_find(&pmu_idr
, event
->attr
.type
);
9355 ret
= perf_try_init_event(pmu
, event
);
9361 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
9362 ret
= perf_try_init_event(pmu
, event
);
9366 if (ret
!= -ENOENT
) {
9371 pmu
= ERR_PTR(-ENOENT
);
9373 srcu_read_unlock(&pmus_srcu
, idx
);
9378 static void attach_sb_event(struct perf_event
*event
)
9380 struct pmu_event_list
*pel
= per_cpu_ptr(&pmu_sb_events
, event
->cpu
);
9382 raw_spin_lock(&pel
->lock
);
9383 list_add_rcu(&event
->sb_list
, &pel
->list
);
9384 raw_spin_unlock(&pel
->lock
);
9388 * We keep a list of all !task (and therefore per-cpu) events
9389 * that need to receive side-band records.
9391 * This avoids having to scan all the various PMU per-cpu contexts
9394 static void account_pmu_sb_event(struct perf_event
*event
)
9396 if (is_sb_event(event
))
9397 attach_sb_event(event
);
9400 static void account_event_cpu(struct perf_event
*event
, int cpu
)
9405 if (is_cgroup_event(event
))
9406 atomic_inc(&per_cpu(perf_cgroup_events
, cpu
));
9409 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9410 static void account_freq_event_nohz(void)
9412 #ifdef CONFIG_NO_HZ_FULL
9413 /* Lock so we don't race with concurrent unaccount */
9414 spin_lock(&nr_freq_lock
);
9415 if (atomic_inc_return(&nr_freq_events
) == 1)
9416 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS
);
9417 spin_unlock(&nr_freq_lock
);
9421 static void account_freq_event(void)
9423 if (tick_nohz_full_enabled())
9424 account_freq_event_nohz();
9426 atomic_inc(&nr_freq_events
);
9430 static void account_event(struct perf_event
*event
)
9437 if (event
->attach_state
& PERF_ATTACH_TASK
)
9439 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
9440 atomic_inc(&nr_mmap_events
);
9441 if (event
->attr
.comm
)
9442 atomic_inc(&nr_comm_events
);
9443 if (event
->attr
.namespaces
)
9444 atomic_inc(&nr_namespaces_events
);
9445 if (event
->attr
.task
)
9446 atomic_inc(&nr_task_events
);
9447 if (event
->attr
.freq
)
9448 account_freq_event();
9449 if (event
->attr
.context_switch
) {
9450 atomic_inc(&nr_switch_events
);
9453 if (has_branch_stack(event
))
9455 if (is_cgroup_event(event
))
9460 * We need the mutex here because static_branch_enable()
9461 * must complete *before* the perf_sched_count increment
9464 if (atomic_inc_not_zero(&perf_sched_count
))
9467 mutex_lock(&perf_sched_mutex
);
9468 if (!atomic_read(&perf_sched_count
)) {
9469 static_branch_enable(&perf_sched_events
);
9471 * Guarantee that all CPUs observe they key change and
9472 * call the perf scheduling hooks before proceeding to
9473 * install events that need them.
9475 synchronize_sched();
9478 * Now that we have waited for the sync_sched(), allow further
9479 * increments to by-pass the mutex.
9481 atomic_inc(&perf_sched_count
);
9482 mutex_unlock(&perf_sched_mutex
);
9486 account_event_cpu(event
, event
->cpu
);
9488 account_pmu_sb_event(event
);
9492 * Allocate and initialize a event structure
9494 static struct perf_event
*
9495 perf_event_alloc(struct perf_event_attr
*attr
, int cpu
,
9496 struct task_struct
*task
,
9497 struct perf_event
*group_leader
,
9498 struct perf_event
*parent_event
,
9499 perf_overflow_handler_t overflow_handler
,
9500 void *context
, int cgroup_fd
)
9503 struct perf_event
*event
;
9504 struct hw_perf_event
*hwc
;
9507 if ((unsigned)cpu
>= nr_cpu_ids
) {
9508 if (!task
|| cpu
!= -1)
9509 return ERR_PTR(-EINVAL
);
9512 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
9514 return ERR_PTR(-ENOMEM
);
9517 * Single events are their own group leaders, with an
9518 * empty sibling list:
9521 group_leader
= event
;
9523 mutex_init(&event
->child_mutex
);
9524 INIT_LIST_HEAD(&event
->child_list
);
9526 INIT_LIST_HEAD(&event
->group_entry
);
9527 INIT_LIST_HEAD(&event
->event_entry
);
9528 INIT_LIST_HEAD(&event
->sibling_list
);
9529 INIT_LIST_HEAD(&event
->rb_entry
);
9530 INIT_LIST_HEAD(&event
->active_entry
);
9531 INIT_LIST_HEAD(&event
->addr_filters
.list
);
9532 INIT_HLIST_NODE(&event
->hlist_entry
);
9535 init_waitqueue_head(&event
->waitq
);
9536 event
->pending_disable
= -1;
9537 init_irq_work(&event
->pending
, perf_pending_event
);
9539 mutex_init(&event
->mmap_mutex
);
9540 raw_spin_lock_init(&event
->addr_filters
.lock
);
9542 atomic_long_set(&event
->refcount
, 1);
9544 event
->attr
= *attr
;
9545 event
->group_leader
= group_leader
;
9549 event
->parent
= parent_event
;
9551 event
->ns
= get_pid_ns(task_active_pid_ns(current
));
9552 event
->id
= atomic64_inc_return(&perf_event_id
);
9554 event
->state
= PERF_EVENT_STATE_INACTIVE
;
9557 event
->attach_state
= PERF_ATTACH_TASK
;
9559 * XXX pmu::event_init needs to know what task to account to
9560 * and we cannot use the ctx information because we need the
9561 * pmu before we get a ctx.
9563 get_task_struct(task
);
9564 event
->hw
.target
= task
;
9567 event
->clock
= &local_clock
;
9569 event
->clock
= parent_event
->clock
;
9571 if (!overflow_handler
&& parent_event
) {
9572 overflow_handler
= parent_event
->overflow_handler
;
9573 context
= parent_event
->overflow_handler_context
;
9574 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9575 if (overflow_handler
== bpf_overflow_handler
) {
9576 struct bpf_prog
*prog
= bpf_prog_inc(parent_event
->prog
);
9579 err
= PTR_ERR(prog
);
9583 event
->orig_overflow_handler
=
9584 parent_event
->orig_overflow_handler
;
9589 if (overflow_handler
) {
9590 event
->overflow_handler
= overflow_handler
;
9591 event
->overflow_handler_context
= context
;
9592 } else if (is_write_backward(event
)){
9593 event
->overflow_handler
= perf_event_output_backward
;
9594 event
->overflow_handler_context
= NULL
;
9596 event
->overflow_handler
= perf_event_output_forward
;
9597 event
->overflow_handler_context
= NULL
;
9600 perf_event__state_init(event
);
9605 hwc
->sample_period
= attr
->sample_period
;
9606 if (attr
->freq
&& attr
->sample_freq
)
9607 hwc
->sample_period
= 1;
9608 hwc
->last_period
= hwc
->sample_period
;
9610 local64_set(&hwc
->period_left
, hwc
->sample_period
);
9613 * We currently do not support PERF_SAMPLE_READ on inherited events.
9614 * See perf_output_read().
9616 if (attr
->inherit
&& (attr
->sample_type
& PERF_SAMPLE_READ
))
9619 if (!has_branch_stack(event
))
9620 event
->attr
.branch_sample_type
= 0;
9622 if (cgroup_fd
!= -1) {
9623 err
= perf_cgroup_connect(cgroup_fd
, event
, attr
, group_leader
);
9628 pmu
= perf_init_event(event
);
9634 err
= exclusive_event_init(event
);
9638 if (has_addr_filter(event
)) {
9639 event
->addr_filters_offs
= kcalloc(pmu
->nr_addr_filters
,
9640 sizeof(unsigned long),
9642 if (!event
->addr_filters_offs
) {
9647 /* force hw sync on the address filters */
9648 event
->addr_filters_gen
= 1;
9651 if (!event
->parent
) {
9652 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
) {
9653 err
= get_callchain_buffers(attr
->sample_max_stack
);
9655 goto err_addr_filters
;
9659 /* symmetric to unaccount_event() in _free_event() */
9660 account_event(event
);
9665 kfree(event
->addr_filters_offs
);
9668 exclusive_event_destroy(event
);
9672 event
->destroy(event
);
9673 module_put(pmu
->module
);
9675 if (is_cgroup_event(event
))
9676 perf_detach_cgroup(event
);
9678 put_pid_ns(event
->ns
);
9679 if (event
->hw
.target
)
9680 put_task_struct(event
->hw
.target
);
9683 return ERR_PTR(err
);
9686 static int perf_copy_attr(struct perf_event_attr __user
*uattr
,
9687 struct perf_event_attr
*attr
)
9692 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
9696 * zero the full structure, so that a short copy will be nice.
9698 memset(attr
, 0, sizeof(*attr
));
9700 ret
= get_user(size
, &uattr
->size
);
9704 if (size
> PAGE_SIZE
) /* silly large */
9707 if (!size
) /* abi compat */
9708 size
= PERF_ATTR_SIZE_VER0
;
9710 if (size
< PERF_ATTR_SIZE_VER0
)
9714 * If we're handed a bigger struct than we know of,
9715 * ensure all the unknown bits are 0 - i.e. new
9716 * user-space does not rely on any kernel feature
9717 * extensions we dont know about yet.
9719 if (size
> sizeof(*attr
)) {
9720 unsigned char __user
*addr
;
9721 unsigned char __user
*end
;
9724 addr
= (void __user
*)uattr
+ sizeof(*attr
);
9725 end
= (void __user
*)uattr
+ size
;
9727 for (; addr
< end
; addr
++) {
9728 ret
= get_user(val
, addr
);
9734 size
= sizeof(*attr
);
9737 ret
= copy_from_user(attr
, uattr
, size
);
9743 if (attr
->__reserved_1
)
9746 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
9749 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
9752 if (attr
->sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
9753 u64 mask
= attr
->branch_sample_type
;
9755 /* only using defined bits */
9756 if (mask
& ~(PERF_SAMPLE_BRANCH_MAX
-1))
9759 /* at least one branch bit must be set */
9760 if (!(mask
& ~PERF_SAMPLE_BRANCH_PLM_ALL
))
9763 /* propagate priv level, when not set for branch */
9764 if (!(mask
& PERF_SAMPLE_BRANCH_PLM_ALL
)) {
9766 /* exclude_kernel checked on syscall entry */
9767 if (!attr
->exclude_kernel
)
9768 mask
|= PERF_SAMPLE_BRANCH_KERNEL
;
9770 if (!attr
->exclude_user
)
9771 mask
|= PERF_SAMPLE_BRANCH_USER
;
9773 if (!attr
->exclude_hv
)
9774 mask
|= PERF_SAMPLE_BRANCH_HV
;
9776 * adjust user setting (for HW filter setup)
9778 attr
->branch_sample_type
= mask
;
9780 /* privileged levels capture (kernel, hv): check permissions */
9781 if ((mask
& PERF_SAMPLE_BRANCH_PERM_PLM
)
9782 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
9786 if (attr
->sample_type
& PERF_SAMPLE_REGS_USER
) {
9787 ret
= perf_reg_validate(attr
->sample_regs_user
);
9792 if (attr
->sample_type
& PERF_SAMPLE_STACK_USER
) {
9793 if (!arch_perf_have_user_stack_dump())
9797 * We have __u32 type for the size, but so far
9798 * we can only use __u16 as maximum due to the
9799 * __u16 sample size limit.
9801 if (attr
->sample_stack_user
>= USHRT_MAX
)
9803 else if (!IS_ALIGNED(attr
->sample_stack_user
, sizeof(u64
)))
9807 if (attr
->sample_type
& PERF_SAMPLE_REGS_INTR
)
9808 ret
= perf_reg_validate(attr
->sample_regs_intr
);
9813 put_user(sizeof(*attr
), &uattr
->size
);
9819 perf_event_set_output(struct perf_event
*event
, struct perf_event
*output_event
)
9821 struct ring_buffer
*rb
= NULL
;
9827 /* don't allow circular references */
9828 if (event
== output_event
)
9832 * Don't allow cross-cpu buffers
9834 if (output_event
->cpu
!= event
->cpu
)
9838 * If its not a per-cpu rb, it must be the same task.
9840 if (output_event
->cpu
== -1 && output_event
->ctx
!= event
->ctx
)
9844 * Mixing clocks in the same buffer is trouble you don't need.
9846 if (output_event
->clock
!= event
->clock
)
9850 * Either writing ring buffer from beginning or from end.
9851 * Mixing is not allowed.
9853 if (is_write_backward(output_event
) != is_write_backward(event
))
9857 * If both events generate aux data, they must be on the same PMU
9859 if (has_aux(event
) && has_aux(output_event
) &&
9860 event
->pmu
!= output_event
->pmu
)
9864 mutex_lock(&event
->mmap_mutex
);
9865 /* Can't redirect output if we've got an active mmap() */
9866 if (atomic_read(&event
->mmap_count
))
9870 /* get the rb we want to redirect to */
9871 rb
= ring_buffer_get(output_event
);
9876 ring_buffer_attach(event
, rb
);
9880 mutex_unlock(&event
->mmap_mutex
);
9886 static void mutex_lock_double(struct mutex
*a
, struct mutex
*b
)
9892 mutex_lock_nested(b
, SINGLE_DEPTH_NESTING
);
9895 static int perf_event_set_clock(struct perf_event
*event
, clockid_t clk_id
)
9897 bool nmi_safe
= false;
9900 case CLOCK_MONOTONIC
:
9901 event
->clock
= &ktime_get_mono_fast_ns
;
9905 case CLOCK_MONOTONIC_RAW
:
9906 event
->clock
= &ktime_get_raw_fast_ns
;
9910 case CLOCK_REALTIME
:
9911 event
->clock
= &ktime_get_real_ns
;
9914 case CLOCK_BOOTTIME
:
9915 event
->clock
= &ktime_get_boot_ns
;
9919 event
->clock
= &ktime_get_tai_ns
;
9926 if (!nmi_safe
&& !(event
->pmu
->capabilities
& PERF_PMU_CAP_NO_NMI
))
9933 * Variation on perf_event_ctx_lock_nested(), except we take two context
9936 static struct perf_event_context
*
9937 __perf_event_ctx_lock_double(struct perf_event
*group_leader
,
9938 struct perf_event_context
*ctx
)
9940 struct perf_event_context
*gctx
;
9944 gctx
= READ_ONCE(group_leader
->ctx
);
9945 if (!atomic_inc_not_zero(&gctx
->refcount
)) {
9951 mutex_lock_double(&gctx
->mutex
, &ctx
->mutex
);
9953 if (group_leader
->ctx
!= gctx
) {
9954 mutex_unlock(&ctx
->mutex
);
9955 mutex_unlock(&gctx
->mutex
);
9964 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9966 * @attr_uptr: event_id type attributes for monitoring/sampling
9969 * @group_fd: group leader event fd
9971 SYSCALL_DEFINE5(perf_event_open
,
9972 struct perf_event_attr __user
*, attr_uptr
,
9973 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
9975 struct perf_event
*group_leader
= NULL
, *output_event
= NULL
;
9976 struct perf_event
*event
, *sibling
;
9977 struct perf_event_attr attr
;
9978 struct perf_event_context
*ctx
, *uninitialized_var(gctx
);
9979 struct file
*event_file
= NULL
;
9980 struct fd group
= {NULL
, 0};
9981 struct task_struct
*task
= NULL
;
9986 int f_flags
= O_RDWR
;
9989 /* for future expandability... */
9990 if (flags
& ~PERF_FLAG_ALL
)
9993 if (perf_paranoid_any() && !capable(CAP_SYS_ADMIN
))
9996 err
= perf_copy_attr(attr_uptr
, &attr
);
10000 if (!attr
.exclude_kernel
) {
10001 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
10005 if (attr
.namespaces
) {
10006 if (!capable(CAP_SYS_ADMIN
))
10011 if (attr
.sample_freq
> sysctl_perf_event_sample_rate
)
10014 if (attr
.sample_period
& (1ULL << 63))
10018 /* Only privileged users can get physical addresses */
10019 if ((attr
.sample_type
& PERF_SAMPLE_PHYS_ADDR
) &&
10020 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
10023 if (!attr
.sample_max_stack
)
10024 attr
.sample_max_stack
= sysctl_perf_event_max_stack
;
10027 * In cgroup mode, the pid argument is used to pass the fd
10028 * opened to the cgroup directory in cgroupfs. The cpu argument
10029 * designates the cpu on which to monitor threads from that
10032 if ((flags
& PERF_FLAG_PID_CGROUP
) && (pid
== -1 || cpu
== -1))
10035 if (flags
& PERF_FLAG_FD_CLOEXEC
)
10036 f_flags
|= O_CLOEXEC
;
10038 event_fd
= get_unused_fd_flags(f_flags
);
10042 if (group_fd
!= -1) {
10043 err
= perf_fget_light(group_fd
, &group
);
10046 group_leader
= group
.file
->private_data
;
10047 if (flags
& PERF_FLAG_FD_OUTPUT
)
10048 output_event
= group_leader
;
10049 if (flags
& PERF_FLAG_FD_NO_GROUP
)
10050 group_leader
= NULL
;
10053 if (pid
!= -1 && !(flags
& PERF_FLAG_PID_CGROUP
)) {
10054 task
= find_lively_task_by_vpid(pid
);
10055 if (IS_ERR(task
)) {
10056 err
= PTR_ERR(task
);
10061 if (task
&& group_leader
&&
10062 group_leader
->attr
.inherit
!= attr
.inherit
) {
10068 err
= mutex_lock_interruptible(&task
->signal
->cred_guard_mutex
);
10073 * Reuse ptrace permission checks for now.
10075 * We must hold cred_guard_mutex across this and any potential
10076 * perf_install_in_context() call for this new event to
10077 * serialize against exec() altering our credentials (and the
10078 * perf_event_exit_task() that could imply).
10081 if (!ptrace_may_access(task
, PTRACE_MODE_READ_REALCREDS
))
10085 if (flags
& PERF_FLAG_PID_CGROUP
)
10088 event
= perf_event_alloc(&attr
, cpu
, task
, group_leader
, NULL
,
10089 NULL
, NULL
, cgroup_fd
);
10090 if (IS_ERR(event
)) {
10091 err
= PTR_ERR(event
);
10095 if (is_sampling_event(event
)) {
10096 if (event
->pmu
->capabilities
& PERF_PMU_CAP_NO_INTERRUPT
) {
10103 * Special case software events and allow them to be part of
10104 * any hardware group.
10108 if (attr
.use_clockid
) {
10109 err
= perf_event_set_clock(event
, attr
.clockid
);
10114 if (pmu
->task_ctx_nr
== perf_sw_context
)
10115 event
->event_caps
|= PERF_EV_CAP_SOFTWARE
;
10117 if (group_leader
&&
10118 (is_software_event(event
) != is_software_event(group_leader
))) {
10119 if (is_software_event(event
)) {
10121 * If event and group_leader are not both a software
10122 * event, and event is, then group leader is not.
10124 * Allow the addition of software events to !software
10125 * groups, this is safe because software events never
10126 * fail to schedule.
10128 pmu
= group_leader
->pmu
;
10129 } else if (is_software_event(group_leader
) &&
10130 (group_leader
->group_caps
& PERF_EV_CAP_SOFTWARE
)) {
10132 * In case the group is a pure software group, and we
10133 * try to add a hardware event, move the whole group to
10134 * the hardware context.
10141 * Get the target context (task or percpu):
10143 ctx
= find_get_context(pmu
, task
, event
);
10145 err
= PTR_ERR(ctx
);
10149 if ((pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
) && group_leader
) {
10155 * Look up the group leader (we will attach this event to it):
10157 if (group_leader
) {
10161 * Do not allow a recursive hierarchy (this new sibling
10162 * becoming part of another group-sibling):
10164 if (group_leader
->group_leader
!= group_leader
)
10167 /* All events in a group should have the same clock */
10168 if (group_leader
->clock
!= event
->clock
)
10172 * Make sure we're both events for the same CPU;
10173 * grouping events for different CPUs is broken; since
10174 * you can never concurrently schedule them anyhow.
10176 if (group_leader
->cpu
!= event
->cpu
)
10180 * Make sure we're both on the same task, or both
10183 if (group_leader
->ctx
->task
!= ctx
->task
)
10187 * Do not allow to attach to a group in a different task
10188 * or CPU context. If we're moving SW events, we'll fix
10189 * this up later, so allow that.
10191 if (!move_group
&& group_leader
->ctx
!= ctx
)
10195 * Only a group leader can be exclusive or pinned
10197 if (attr
.exclusive
|| attr
.pinned
)
10201 if (output_event
) {
10202 err
= perf_event_set_output(event
, output_event
);
10207 event_file
= anon_inode_getfile("[perf_event]", &perf_fops
, event
,
10209 if (IS_ERR(event_file
)) {
10210 err
= PTR_ERR(event_file
);
10216 gctx
= __perf_event_ctx_lock_double(group_leader
, ctx
);
10218 if (gctx
->task
== TASK_TOMBSTONE
) {
10224 * Check if we raced against another sys_perf_event_open() call
10225 * moving the software group underneath us.
10227 if (!(group_leader
->group_caps
& PERF_EV_CAP_SOFTWARE
)) {
10229 * If someone moved the group out from under us, check
10230 * if this new event wound up on the same ctx, if so
10231 * its the regular !move_group case, otherwise fail.
10237 perf_event_ctx_unlock(group_leader
, gctx
);
10242 mutex_lock(&ctx
->mutex
);
10245 if (ctx
->task
== TASK_TOMBSTONE
) {
10250 if (!perf_event_validate_size(event
)) {
10257 * Check if the @cpu we're creating an event for is online.
10259 * We use the perf_cpu_context::ctx::mutex to serialize against
10260 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10262 struct perf_cpu_context
*cpuctx
=
10263 container_of(ctx
, struct perf_cpu_context
, ctx
);
10265 if (!cpuctx
->online
) {
10273 * Must be under the same ctx::mutex as perf_install_in_context(),
10274 * because we need to serialize with concurrent event creation.
10276 if (!exclusive_event_installable(event
, ctx
)) {
10277 /* exclusive and group stuff are assumed mutually exclusive */
10278 WARN_ON_ONCE(move_group
);
10284 WARN_ON_ONCE(ctx
->parent_ctx
);
10287 * This is the point on no return; we cannot fail hereafter. This is
10288 * where we start modifying current state.
10293 * See perf_event_ctx_lock() for comments on the details
10294 * of swizzling perf_event::ctx.
10296 perf_remove_from_context(group_leader
, 0);
10299 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
10301 perf_remove_from_context(sibling
, 0);
10306 * Wait for everybody to stop referencing the events through
10307 * the old lists, before installing it on new lists.
10312 * Install the group siblings before the group leader.
10314 * Because a group leader will try and install the entire group
10315 * (through the sibling list, which is still in-tact), we can
10316 * end up with siblings installed in the wrong context.
10318 * By installing siblings first we NO-OP because they're not
10319 * reachable through the group lists.
10321 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
10323 perf_event__state_init(sibling
);
10324 perf_install_in_context(ctx
, sibling
, sibling
->cpu
);
10329 * Removing from the context ends up with disabled
10330 * event. What we want here is event in the initial
10331 * startup state, ready to be add into new context.
10333 perf_event__state_init(group_leader
);
10334 perf_install_in_context(ctx
, group_leader
, group_leader
->cpu
);
10339 * Precalculate sample_data sizes; do while holding ctx::mutex such
10340 * that we're serialized against further additions and before
10341 * perf_install_in_context() which is the point the event is active and
10342 * can use these values.
10344 perf_event__header_size(event
);
10345 perf_event__id_header_size(event
);
10347 event
->owner
= current
;
10349 perf_install_in_context(ctx
, event
, event
->cpu
);
10350 perf_unpin_context(ctx
);
10353 perf_event_ctx_unlock(group_leader
, gctx
);
10354 mutex_unlock(&ctx
->mutex
);
10357 mutex_unlock(&task
->signal
->cred_guard_mutex
);
10358 put_task_struct(task
);
10361 mutex_lock(¤t
->perf_event_mutex
);
10362 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
10363 mutex_unlock(¤t
->perf_event_mutex
);
10366 * Drop the reference on the group_event after placing the
10367 * new event on the sibling_list. This ensures destruction
10368 * of the group leader will find the pointer to itself in
10369 * perf_group_detach().
10372 fd_install(event_fd
, event_file
);
10377 perf_event_ctx_unlock(group_leader
, gctx
);
10378 mutex_unlock(&ctx
->mutex
);
10382 perf_unpin_context(ctx
);
10386 * If event_file is set, the fput() above will have called ->release()
10387 * and that will take care of freeing the event.
10393 mutex_unlock(&task
->signal
->cred_guard_mutex
);
10396 put_task_struct(task
);
10400 put_unused_fd(event_fd
);
10405 * perf_event_create_kernel_counter
10407 * @attr: attributes of the counter to create
10408 * @cpu: cpu in which the counter is bound
10409 * @task: task to profile (NULL for percpu)
10411 struct perf_event
*
10412 perf_event_create_kernel_counter(struct perf_event_attr
*attr
, int cpu
,
10413 struct task_struct
*task
,
10414 perf_overflow_handler_t overflow_handler
,
10417 struct perf_event_context
*ctx
;
10418 struct perf_event
*event
;
10422 * Get the target context (task or percpu):
10425 event
= perf_event_alloc(attr
, cpu
, task
, NULL
, NULL
,
10426 overflow_handler
, context
, -1);
10427 if (IS_ERR(event
)) {
10428 err
= PTR_ERR(event
);
10432 /* Mark owner so we could distinguish it from user events. */
10433 event
->owner
= TASK_TOMBSTONE
;
10435 ctx
= find_get_context(event
->pmu
, task
, event
);
10437 err
= PTR_ERR(ctx
);
10441 WARN_ON_ONCE(ctx
->parent_ctx
);
10442 mutex_lock(&ctx
->mutex
);
10443 if (ctx
->task
== TASK_TOMBSTONE
) {
10450 * Check if the @cpu we're creating an event for is online.
10452 * We use the perf_cpu_context::ctx::mutex to serialize against
10453 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10455 struct perf_cpu_context
*cpuctx
=
10456 container_of(ctx
, struct perf_cpu_context
, ctx
);
10457 if (!cpuctx
->online
) {
10463 if (!exclusive_event_installable(event
, ctx
)) {
10468 perf_install_in_context(ctx
, event
, event
->cpu
);
10469 perf_unpin_context(ctx
);
10470 mutex_unlock(&ctx
->mutex
);
10475 mutex_unlock(&ctx
->mutex
);
10476 perf_unpin_context(ctx
);
10481 return ERR_PTR(err
);
10483 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter
);
10485 void perf_pmu_migrate_context(struct pmu
*pmu
, int src_cpu
, int dst_cpu
)
10487 struct perf_event_context
*src_ctx
;
10488 struct perf_event_context
*dst_ctx
;
10489 struct perf_event
*event
, *tmp
;
10492 src_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, src_cpu
)->ctx
;
10493 dst_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, dst_cpu
)->ctx
;
10496 * See perf_event_ctx_lock() for comments on the details
10497 * of swizzling perf_event::ctx.
10499 mutex_lock_double(&src_ctx
->mutex
, &dst_ctx
->mutex
);
10500 list_for_each_entry_safe(event
, tmp
, &src_ctx
->event_list
,
10502 perf_remove_from_context(event
, 0);
10503 unaccount_event_cpu(event
, src_cpu
);
10505 list_add(&event
->migrate_entry
, &events
);
10509 * Wait for the events to quiesce before re-instating them.
10514 * Re-instate events in 2 passes.
10516 * Skip over group leaders and only install siblings on this first
10517 * pass, siblings will not get enabled without a leader, however a
10518 * leader will enable its siblings, even if those are still on the old
10521 list_for_each_entry_safe(event
, tmp
, &events
, migrate_entry
) {
10522 if (event
->group_leader
== event
)
10525 list_del(&event
->migrate_entry
);
10526 if (event
->state
>= PERF_EVENT_STATE_OFF
)
10527 event
->state
= PERF_EVENT_STATE_INACTIVE
;
10528 account_event_cpu(event
, dst_cpu
);
10529 perf_install_in_context(dst_ctx
, event
, dst_cpu
);
10534 * Once all the siblings are setup properly, install the group leaders
10537 list_for_each_entry_safe(event
, tmp
, &events
, migrate_entry
) {
10538 list_del(&event
->migrate_entry
);
10539 if (event
->state
>= PERF_EVENT_STATE_OFF
)
10540 event
->state
= PERF_EVENT_STATE_INACTIVE
;
10541 account_event_cpu(event
, dst_cpu
);
10542 perf_install_in_context(dst_ctx
, event
, dst_cpu
);
10545 mutex_unlock(&dst_ctx
->mutex
);
10546 mutex_unlock(&src_ctx
->mutex
);
10548 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context
);
10550 static void sync_child_event(struct perf_event
*child_event
,
10551 struct task_struct
*child
)
10553 struct perf_event
*parent_event
= child_event
->parent
;
10556 if (child_event
->attr
.inherit_stat
)
10557 perf_event_read_event(child_event
, child
);
10559 child_val
= perf_event_count(child_event
);
10562 * Add back the child's count to the parent's count:
10564 atomic64_add(child_val
, &parent_event
->child_count
);
10565 atomic64_add(child_event
->total_time_enabled
,
10566 &parent_event
->child_total_time_enabled
);
10567 atomic64_add(child_event
->total_time_running
,
10568 &parent_event
->child_total_time_running
);
10572 perf_event_exit_event(struct perf_event
*child_event
,
10573 struct perf_event_context
*child_ctx
,
10574 struct task_struct
*child
)
10576 struct perf_event
*parent_event
= child_event
->parent
;
10579 * Do not destroy the 'original' grouping; because of the context
10580 * switch optimization the original events could've ended up in a
10581 * random child task.
10583 * If we were to destroy the original group, all group related
10584 * operations would cease to function properly after this random
10587 * Do destroy all inherited groups, we don't care about those
10588 * and being thorough is better.
10590 raw_spin_lock_irq(&child_ctx
->lock
);
10591 WARN_ON_ONCE(child_ctx
->is_active
);
10594 perf_group_detach(child_event
);
10595 list_del_event(child_event
, child_ctx
);
10596 perf_event_set_state(child_event
, PERF_EVENT_STATE_EXIT
); /* is_event_hup() */
10597 raw_spin_unlock_irq(&child_ctx
->lock
);
10600 * Parent events are governed by their filedesc, retain them.
10602 if (!parent_event
) {
10603 perf_event_wakeup(child_event
);
10607 * Child events can be cleaned up.
10610 sync_child_event(child_event
, child
);
10613 * Remove this event from the parent's list
10615 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
10616 mutex_lock(&parent_event
->child_mutex
);
10617 list_del_init(&child_event
->child_list
);
10618 mutex_unlock(&parent_event
->child_mutex
);
10621 * Kick perf_poll() for is_event_hup().
10623 perf_event_wakeup(parent_event
);
10624 free_event(child_event
);
10625 put_event(parent_event
);
10628 static void perf_event_exit_task_context(struct task_struct
*child
, int ctxn
)
10630 struct perf_event_context
*child_ctx
, *clone_ctx
= NULL
;
10631 struct perf_event
*child_event
, *next
;
10633 WARN_ON_ONCE(child
!= current
);
10635 child_ctx
= perf_pin_task_context(child
, ctxn
);
10640 * In order to reduce the amount of tricky in ctx tear-down, we hold
10641 * ctx::mutex over the entire thing. This serializes against almost
10642 * everything that wants to access the ctx.
10644 * The exception is sys_perf_event_open() /
10645 * perf_event_create_kernel_count() which does find_get_context()
10646 * without ctx::mutex (it cannot because of the move_group double mutex
10647 * lock thing). See the comments in perf_install_in_context().
10649 mutex_lock(&child_ctx
->mutex
);
10652 * In a single ctx::lock section, de-schedule the events and detach the
10653 * context from the task such that we cannot ever get it scheduled back
10656 raw_spin_lock_irq(&child_ctx
->lock
);
10657 task_ctx_sched_out(__get_cpu_context(child_ctx
), child_ctx
, EVENT_ALL
);
10660 * Now that the context is inactive, destroy the task <-> ctx relation
10661 * and mark the context dead.
10663 RCU_INIT_POINTER(child
->perf_event_ctxp
[ctxn
], NULL
);
10664 put_ctx(child_ctx
); /* cannot be last */
10665 WRITE_ONCE(child_ctx
->task
, TASK_TOMBSTONE
);
10666 put_task_struct(current
); /* cannot be last */
10668 clone_ctx
= unclone_ctx(child_ctx
);
10669 raw_spin_unlock_irq(&child_ctx
->lock
);
10672 put_ctx(clone_ctx
);
10675 * Report the task dead after unscheduling the events so that we
10676 * won't get any samples after PERF_RECORD_EXIT. We can however still
10677 * get a few PERF_RECORD_READ events.
10679 perf_event_task(child
, child_ctx
, 0);
10681 list_for_each_entry_safe(child_event
, next
, &child_ctx
->event_list
, event_entry
)
10682 perf_event_exit_event(child_event
, child_ctx
, child
);
10684 mutex_unlock(&child_ctx
->mutex
);
10686 put_ctx(child_ctx
);
10690 * When a child task exits, feed back event values to parent events.
10692 * Can be called with cred_guard_mutex held when called from
10693 * install_exec_creds().
10695 void perf_event_exit_task(struct task_struct
*child
)
10697 struct perf_event
*event
, *tmp
;
10700 mutex_lock(&child
->perf_event_mutex
);
10701 list_for_each_entry_safe(event
, tmp
, &child
->perf_event_list
,
10703 list_del_init(&event
->owner_entry
);
10706 * Ensure the list deletion is visible before we clear
10707 * the owner, closes a race against perf_release() where
10708 * we need to serialize on the owner->perf_event_mutex.
10710 smp_store_release(&event
->owner
, NULL
);
10712 mutex_unlock(&child
->perf_event_mutex
);
10714 for_each_task_context_nr(ctxn
)
10715 perf_event_exit_task_context(child
, ctxn
);
10718 * The perf_event_exit_task_context calls perf_event_task
10719 * with child's task_ctx, which generates EXIT events for
10720 * child contexts and sets child->perf_event_ctxp[] to NULL.
10721 * At this point we need to send EXIT events to cpu contexts.
10723 perf_event_task(child
, NULL
, 0);
10726 static void perf_free_event(struct perf_event
*event
,
10727 struct perf_event_context
*ctx
)
10729 struct perf_event
*parent
= event
->parent
;
10731 if (WARN_ON_ONCE(!parent
))
10734 mutex_lock(&parent
->child_mutex
);
10735 list_del_init(&event
->child_list
);
10736 mutex_unlock(&parent
->child_mutex
);
10740 raw_spin_lock_irq(&ctx
->lock
);
10741 perf_group_detach(event
);
10742 list_del_event(event
, ctx
);
10743 raw_spin_unlock_irq(&ctx
->lock
);
10748 * Free an unexposed, unused context as created by inheritance by
10749 * perf_event_init_task below, used by fork() in case of fail.
10751 * Not all locks are strictly required, but take them anyway to be nice and
10752 * help out with the lockdep assertions.
10754 void perf_event_free_task(struct task_struct
*task
)
10756 struct perf_event_context
*ctx
;
10757 struct perf_event
*event
, *tmp
;
10760 for_each_task_context_nr(ctxn
) {
10761 ctx
= task
->perf_event_ctxp
[ctxn
];
10765 mutex_lock(&ctx
->mutex
);
10766 raw_spin_lock_irq(&ctx
->lock
);
10768 * Destroy the task <-> ctx relation and mark the context dead.
10770 * This is important because even though the task hasn't been
10771 * exposed yet the context has been (through child_list).
10773 RCU_INIT_POINTER(task
->perf_event_ctxp
[ctxn
], NULL
);
10774 WRITE_ONCE(ctx
->task
, TASK_TOMBSTONE
);
10775 put_task_struct(task
); /* cannot be last */
10776 raw_spin_unlock_irq(&ctx
->lock
);
10778 list_for_each_entry_safe(event
, tmp
, &ctx
->event_list
, event_entry
)
10779 perf_free_event(event
, ctx
);
10781 mutex_unlock(&ctx
->mutex
);
10786 void perf_event_delayed_put(struct task_struct
*task
)
10790 for_each_task_context_nr(ctxn
)
10791 WARN_ON_ONCE(task
->perf_event_ctxp
[ctxn
]);
10794 struct file
*perf_event_get(unsigned int fd
)
10798 file
= fget_raw(fd
);
10800 return ERR_PTR(-EBADF
);
10802 if (file
->f_op
!= &perf_fops
) {
10804 return ERR_PTR(-EBADF
);
10810 const struct perf_event_attr
*perf_event_attrs(struct perf_event
*event
)
10813 return ERR_PTR(-EINVAL
);
10815 return &event
->attr
;
10819 * Inherit a event from parent task to child task.
10822 * - valid pointer on success
10823 * - NULL for orphaned events
10824 * - IS_ERR() on error
10826 static struct perf_event
*
10827 inherit_event(struct perf_event
*parent_event
,
10828 struct task_struct
*parent
,
10829 struct perf_event_context
*parent_ctx
,
10830 struct task_struct
*child
,
10831 struct perf_event
*group_leader
,
10832 struct perf_event_context
*child_ctx
)
10834 enum perf_event_state parent_state
= parent_event
->state
;
10835 struct perf_event
*child_event
;
10836 unsigned long flags
;
10839 * Instead of creating recursive hierarchies of events,
10840 * we link inherited events back to the original parent,
10841 * which has a filp for sure, which we use as the reference
10844 if (parent_event
->parent
)
10845 parent_event
= parent_event
->parent
;
10847 child_event
= perf_event_alloc(&parent_event
->attr
,
10850 group_leader
, parent_event
,
10852 if (IS_ERR(child_event
))
10853 return child_event
;
10856 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10857 * must be under the same lock in order to serialize against
10858 * perf_event_release_kernel(), such that either we must observe
10859 * is_orphaned_event() or they will observe us on the child_list.
10861 mutex_lock(&parent_event
->child_mutex
);
10862 if (is_orphaned_event(parent_event
) ||
10863 !atomic_long_inc_not_zero(&parent_event
->refcount
)) {
10864 mutex_unlock(&parent_event
->child_mutex
);
10865 free_event(child_event
);
10869 get_ctx(child_ctx
);
10872 * Make the child state follow the state of the parent event,
10873 * not its attr.disabled bit. We hold the parent's mutex,
10874 * so we won't race with perf_event_{en, dis}able_family.
10876 if (parent_state
>= PERF_EVENT_STATE_INACTIVE
)
10877 child_event
->state
= PERF_EVENT_STATE_INACTIVE
;
10879 child_event
->state
= PERF_EVENT_STATE_OFF
;
10881 if (parent_event
->attr
.freq
) {
10882 u64 sample_period
= parent_event
->hw
.sample_period
;
10883 struct hw_perf_event
*hwc
= &child_event
->hw
;
10885 hwc
->sample_period
= sample_period
;
10886 hwc
->last_period
= sample_period
;
10888 local64_set(&hwc
->period_left
, sample_period
);
10891 child_event
->ctx
= child_ctx
;
10892 child_event
->overflow_handler
= parent_event
->overflow_handler
;
10893 child_event
->overflow_handler_context
10894 = parent_event
->overflow_handler_context
;
10897 * Precalculate sample_data sizes
10899 perf_event__header_size(child_event
);
10900 perf_event__id_header_size(child_event
);
10903 * Link it up in the child's context:
10905 raw_spin_lock_irqsave(&child_ctx
->lock
, flags
);
10906 add_event_to_ctx(child_event
, child_ctx
);
10907 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
10910 * Link this into the parent event's child list
10912 list_add_tail(&child_event
->child_list
, &parent_event
->child_list
);
10913 mutex_unlock(&parent_event
->child_mutex
);
10915 return child_event
;
10919 * Inherits an event group.
10921 * This will quietly suppress orphaned events; !inherit_event() is not an error.
10922 * This matches with perf_event_release_kernel() removing all child events.
10928 static int inherit_group(struct perf_event
*parent_event
,
10929 struct task_struct
*parent
,
10930 struct perf_event_context
*parent_ctx
,
10931 struct task_struct
*child
,
10932 struct perf_event_context
*child_ctx
)
10934 struct perf_event
*leader
;
10935 struct perf_event
*sub
;
10936 struct perf_event
*child_ctr
;
10938 leader
= inherit_event(parent_event
, parent
, parent_ctx
,
10939 child
, NULL
, child_ctx
);
10940 if (IS_ERR(leader
))
10941 return PTR_ERR(leader
);
10943 * @leader can be NULL here because of is_orphaned_event(). In this
10944 * case inherit_event() will create individual events, similar to what
10945 * perf_group_detach() would do anyway.
10947 list_for_each_entry(sub
, &parent_event
->sibling_list
, group_entry
) {
10948 child_ctr
= inherit_event(sub
, parent
, parent_ctx
,
10949 child
, leader
, child_ctx
);
10950 if (IS_ERR(child_ctr
))
10951 return PTR_ERR(child_ctr
);
10957 * Creates the child task context and tries to inherit the event-group.
10959 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
10960 * inherited_all set when we 'fail' to inherit an orphaned event; this is
10961 * consistent with perf_event_release_kernel() removing all child events.
10968 inherit_task_group(struct perf_event
*event
, struct task_struct
*parent
,
10969 struct perf_event_context
*parent_ctx
,
10970 struct task_struct
*child
, int ctxn
,
10971 int *inherited_all
)
10974 struct perf_event_context
*child_ctx
;
10976 if (!event
->attr
.inherit
) {
10977 *inherited_all
= 0;
10981 child_ctx
= child
->perf_event_ctxp
[ctxn
];
10984 * This is executed from the parent task context, so
10985 * inherit events that have been marked for cloning.
10986 * First allocate and initialize a context for the
10989 child_ctx
= alloc_perf_context(parent_ctx
->pmu
, child
);
10993 child
->perf_event_ctxp
[ctxn
] = child_ctx
;
10996 ret
= inherit_group(event
, parent
, parent_ctx
,
11000 *inherited_all
= 0;
11006 * Initialize the perf_event context in task_struct
11008 static int perf_event_init_context(struct task_struct
*child
, int ctxn
)
11010 struct perf_event_context
*child_ctx
, *parent_ctx
;
11011 struct perf_event_context
*cloned_ctx
;
11012 struct perf_event
*event
;
11013 struct task_struct
*parent
= current
;
11014 int inherited_all
= 1;
11015 unsigned long flags
;
11018 if (likely(!parent
->perf_event_ctxp
[ctxn
]))
11022 * If the parent's context is a clone, pin it so it won't get
11023 * swapped under us.
11025 parent_ctx
= perf_pin_task_context(parent
, ctxn
);
11030 * No need to check if parent_ctx != NULL here; since we saw
11031 * it non-NULL earlier, the only reason for it to become NULL
11032 * is if we exit, and since we're currently in the middle of
11033 * a fork we can't be exiting at the same time.
11037 * Lock the parent list. No need to lock the child - not PID
11038 * hashed yet and not running, so nobody can access it.
11040 mutex_lock(&parent_ctx
->mutex
);
11043 * We dont have to disable NMIs - we are only looking at
11044 * the list, not manipulating it:
11046 list_for_each_entry(event
, &parent_ctx
->pinned_groups
, group_entry
) {
11047 ret
= inherit_task_group(event
, parent
, parent_ctx
,
11048 child
, ctxn
, &inherited_all
);
11054 * We can't hold ctx->lock when iterating the ->flexible_group list due
11055 * to allocations, but we need to prevent rotation because
11056 * rotate_ctx() will change the list from interrupt context.
11058 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
11059 parent_ctx
->rotate_disable
= 1;
11060 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
11062 list_for_each_entry(event
, &parent_ctx
->flexible_groups
, group_entry
) {
11063 ret
= inherit_task_group(event
, parent
, parent_ctx
,
11064 child
, ctxn
, &inherited_all
);
11069 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
11070 parent_ctx
->rotate_disable
= 0;
11072 child_ctx
= child
->perf_event_ctxp
[ctxn
];
11074 if (child_ctx
&& inherited_all
) {
11076 * Mark the child context as a clone of the parent
11077 * context, or of whatever the parent is a clone of.
11079 * Note that if the parent is a clone, the holding of
11080 * parent_ctx->lock avoids it from being uncloned.
11082 cloned_ctx
= parent_ctx
->parent_ctx
;
11084 child_ctx
->parent_ctx
= cloned_ctx
;
11085 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
11087 child_ctx
->parent_ctx
= parent_ctx
;
11088 child_ctx
->parent_gen
= parent_ctx
->generation
;
11090 get_ctx(child_ctx
->parent_ctx
);
11093 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
11095 mutex_unlock(&parent_ctx
->mutex
);
11097 perf_unpin_context(parent_ctx
);
11098 put_ctx(parent_ctx
);
11104 * Initialize the perf_event context in task_struct
11106 int perf_event_init_task(struct task_struct
*child
)
11110 memset(child
->perf_event_ctxp
, 0, sizeof(child
->perf_event_ctxp
));
11111 mutex_init(&child
->perf_event_mutex
);
11112 INIT_LIST_HEAD(&child
->perf_event_list
);
11114 for_each_task_context_nr(ctxn
) {
11115 ret
= perf_event_init_context(child
, ctxn
);
11117 perf_event_free_task(child
);
11125 static void __init
perf_event_init_all_cpus(void)
11127 struct swevent_htable
*swhash
;
11130 zalloc_cpumask_var(&perf_online_mask
, GFP_KERNEL
);
11132 for_each_possible_cpu(cpu
) {
11133 swhash
= &per_cpu(swevent_htable
, cpu
);
11134 mutex_init(&swhash
->hlist_mutex
);
11135 INIT_LIST_HEAD(&per_cpu(active_ctx_list
, cpu
));
11137 INIT_LIST_HEAD(&per_cpu(pmu_sb_events
.list
, cpu
));
11138 raw_spin_lock_init(&per_cpu(pmu_sb_events
.lock
, cpu
));
11140 #ifdef CONFIG_CGROUP_PERF
11141 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list
, cpu
));
11143 INIT_LIST_HEAD(&per_cpu(sched_cb_list
, cpu
));
11147 void perf_swevent_init_cpu(unsigned int cpu
)
11149 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
11151 mutex_lock(&swhash
->hlist_mutex
);
11152 if (swhash
->hlist_refcount
> 0 && !swevent_hlist_deref(swhash
)) {
11153 struct swevent_hlist
*hlist
;
11155 hlist
= kzalloc_node(sizeof(*hlist
), GFP_KERNEL
, cpu_to_node(cpu
));
11157 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
11159 mutex_unlock(&swhash
->hlist_mutex
);
11162 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11163 static void __perf_event_exit_context(void *__info
)
11165 struct perf_event_context
*ctx
= __info
;
11166 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
11167 struct perf_event
*event
;
11169 raw_spin_lock(&ctx
->lock
);
11170 ctx_sched_out(ctx
, cpuctx
, EVENT_TIME
);
11171 list_for_each_entry(event
, &ctx
->event_list
, event_entry
)
11172 __perf_remove_from_context(event
, cpuctx
, ctx
, (void *)DETACH_GROUP
);
11173 raw_spin_unlock(&ctx
->lock
);
11176 static void perf_event_exit_cpu_context(int cpu
)
11178 struct perf_cpu_context
*cpuctx
;
11179 struct perf_event_context
*ctx
;
11182 mutex_lock(&pmus_lock
);
11183 list_for_each_entry(pmu
, &pmus
, entry
) {
11184 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
11185 ctx
= &cpuctx
->ctx
;
11187 mutex_lock(&ctx
->mutex
);
11188 smp_call_function_single(cpu
, __perf_event_exit_context
, ctx
, 1);
11189 cpuctx
->online
= 0;
11190 mutex_unlock(&ctx
->mutex
);
11192 cpumask_clear_cpu(cpu
, perf_online_mask
);
11193 mutex_unlock(&pmus_lock
);
11197 static void perf_event_exit_cpu_context(int cpu
) { }
11201 int perf_event_init_cpu(unsigned int cpu
)
11203 struct perf_cpu_context
*cpuctx
;
11204 struct perf_event_context
*ctx
;
11207 perf_swevent_init_cpu(cpu
);
11209 mutex_lock(&pmus_lock
);
11210 cpumask_set_cpu(cpu
, perf_online_mask
);
11211 list_for_each_entry(pmu
, &pmus
, entry
) {
11212 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
11213 ctx
= &cpuctx
->ctx
;
11215 mutex_lock(&ctx
->mutex
);
11216 cpuctx
->online
= 1;
11217 mutex_unlock(&ctx
->mutex
);
11219 mutex_unlock(&pmus_lock
);
11224 int perf_event_exit_cpu(unsigned int cpu
)
11226 perf_event_exit_cpu_context(cpu
);
11231 perf_reboot(struct notifier_block
*notifier
, unsigned long val
, void *v
)
11235 for_each_online_cpu(cpu
)
11236 perf_event_exit_cpu(cpu
);
11242 * Run the perf reboot notifier at the very last possible moment so that
11243 * the generic watchdog code runs as long as possible.
11245 static struct notifier_block perf_reboot_notifier
= {
11246 .notifier_call
= perf_reboot
,
11247 .priority
= INT_MIN
,
11250 void __init
perf_event_init(void)
11254 idr_init(&pmu_idr
);
11256 perf_event_init_all_cpus();
11257 init_srcu_struct(&pmus_srcu
);
11258 perf_pmu_register(&perf_swevent
, "software", PERF_TYPE_SOFTWARE
);
11259 perf_pmu_register(&perf_cpu_clock
, NULL
, -1);
11260 perf_pmu_register(&perf_task_clock
, NULL
, -1);
11261 perf_tp_register();
11262 perf_event_init_cpu(smp_processor_id());
11263 register_reboot_notifier(&perf_reboot_notifier
);
11265 ret
= init_hw_breakpoint();
11266 WARN(ret
, "hw_breakpoint initialization failed with: %d", ret
);
11269 * Build time assertion that we keep the data_head at the intended
11270 * location. IOW, validation we got the __reserved[] size right.
11272 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page
, data_head
))
11276 ssize_t
perf_event_sysfs_show(struct device
*dev
, struct device_attribute
*attr
,
11279 struct perf_pmu_events_attr
*pmu_attr
=
11280 container_of(attr
, struct perf_pmu_events_attr
, attr
);
11282 if (pmu_attr
->event_str
)
11283 return sprintf(page
, "%s\n", pmu_attr
->event_str
);
11287 EXPORT_SYMBOL_GPL(perf_event_sysfs_show
);
11289 static int __init
perf_event_sysfs_init(void)
11294 mutex_lock(&pmus_lock
);
11296 ret
= bus_register(&pmu_bus
);
11300 list_for_each_entry(pmu
, &pmus
, entry
) {
11301 if (!pmu
->name
|| pmu
->type
< 0)
11304 ret
= pmu_dev_alloc(pmu
);
11305 WARN(ret
, "Failed to register pmu: %s, reason %d\n", pmu
->name
, ret
);
11307 pmu_bus_running
= 1;
11311 mutex_unlock(&pmus_lock
);
11315 device_initcall(perf_event_sysfs_init
);
11317 #ifdef CONFIG_CGROUP_PERF
11318 static struct cgroup_subsys_state
*
11319 perf_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
11321 struct perf_cgroup
*jc
;
11323 jc
= kzalloc(sizeof(*jc
), GFP_KERNEL
);
11325 return ERR_PTR(-ENOMEM
);
11327 jc
->info
= alloc_percpu(struct perf_cgroup_info
);
11330 return ERR_PTR(-ENOMEM
);
11336 static void perf_cgroup_css_free(struct cgroup_subsys_state
*css
)
11338 struct perf_cgroup
*jc
= container_of(css
, struct perf_cgroup
, css
);
11340 free_percpu(jc
->info
);
11344 static int __perf_cgroup_move(void *info
)
11346 struct task_struct
*task
= info
;
11348 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
| PERF_CGROUP_SWIN
);
11353 static void perf_cgroup_attach(struct cgroup_taskset
*tset
)
11355 struct task_struct
*task
;
11356 struct cgroup_subsys_state
*css
;
11358 cgroup_taskset_for_each(task
, css
, tset
)
11359 task_function_call(task
, __perf_cgroup_move
, task
);
11362 struct cgroup_subsys perf_event_cgrp_subsys
= {
11363 .css_alloc
= perf_cgroup_css_alloc
,
11364 .css_free
= perf_cgroup_css_free
,
11365 .attach
= perf_cgroup_attach
,
11367 * Implicitly enable on dfl hierarchy so that perf events can
11368 * always be filtered by cgroup2 path as long as perf_event
11369 * controller is not mounted on a legacy hierarchy.
11371 .implicit_on_dfl
= true,
11374 #endif /* CONFIG_CGROUP_PERF */