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>
52 #include <asm/irq_regs.h>
54 typedef int (*remote_function_f
)(void *);
56 struct remote_function_call
{
57 struct task_struct
*p
;
58 remote_function_f func
;
63 static void remote_function(void *data
)
65 struct remote_function_call
*tfc
= data
;
66 struct task_struct
*p
= tfc
->p
;
70 if (task_cpu(p
) != smp_processor_id())
74 * Now that we're on right CPU with IRQs disabled, we can test
75 * if we hit the right task without races.
78 tfc
->ret
= -ESRCH
; /* No such (running) process */
83 tfc
->ret
= tfc
->func(tfc
->info
);
87 * task_function_call - call a function on the cpu on which a task runs
88 * @p: the task to evaluate
89 * @func: the function to be called
90 * @info: the function call argument
92 * Calls the function @func when the task is currently running. This might
93 * be on the current CPU, which just calls the function directly
95 * returns: @func return value, or
96 * -ESRCH - when the process isn't running
97 * -EAGAIN - when the process moved away
100 task_function_call(struct task_struct
*p
, remote_function_f func
, void *info
)
102 struct remote_function_call data
= {
111 ret
= smp_call_function_single(task_cpu(p
), remote_function
, &data
, 1);
114 } while (ret
== -EAGAIN
);
120 * cpu_function_call - call a function on the cpu
121 * @func: the function to be called
122 * @info: the function call argument
124 * Calls the function @func on the remote cpu.
126 * returns: @func return value or -ENXIO when the cpu is offline
128 static int cpu_function_call(int cpu
, remote_function_f func
, void *info
)
130 struct remote_function_call data
= {
134 .ret
= -ENXIO
, /* No such CPU */
137 smp_call_function_single(cpu
, remote_function
, &data
, 1);
142 static inline struct perf_cpu_context
*
143 __get_cpu_context(struct perf_event_context
*ctx
)
145 return this_cpu_ptr(ctx
->pmu
->pmu_cpu_context
);
148 static void perf_ctx_lock(struct perf_cpu_context
*cpuctx
,
149 struct perf_event_context
*ctx
)
151 raw_spin_lock(&cpuctx
->ctx
.lock
);
153 raw_spin_lock(&ctx
->lock
);
156 static void perf_ctx_unlock(struct perf_cpu_context
*cpuctx
,
157 struct perf_event_context
*ctx
)
160 raw_spin_unlock(&ctx
->lock
);
161 raw_spin_unlock(&cpuctx
->ctx
.lock
);
164 #define TASK_TOMBSTONE ((void *)-1L)
166 static bool is_kernel_event(struct perf_event
*event
)
168 return READ_ONCE(event
->owner
) == TASK_TOMBSTONE
;
172 * On task ctx scheduling...
174 * When !ctx->nr_events a task context will not be scheduled. This means
175 * we can disable the scheduler hooks (for performance) without leaving
176 * pending task ctx state.
178 * This however results in two special cases:
180 * - removing the last event from a task ctx; this is relatively straight
181 * forward and is done in __perf_remove_from_context.
183 * - adding the first event to a task ctx; this is tricky because we cannot
184 * rely on ctx->is_active and therefore cannot use event_function_call().
185 * See perf_install_in_context().
187 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
190 typedef void (*event_f
)(struct perf_event
*, struct perf_cpu_context
*,
191 struct perf_event_context
*, void *);
193 struct event_function_struct
{
194 struct perf_event
*event
;
199 static int event_function(void *info
)
201 struct event_function_struct
*efs
= info
;
202 struct perf_event
*event
= efs
->event
;
203 struct perf_event_context
*ctx
= event
->ctx
;
204 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
205 struct perf_event_context
*task_ctx
= cpuctx
->task_ctx
;
208 WARN_ON_ONCE(!irqs_disabled());
210 perf_ctx_lock(cpuctx
, task_ctx
);
212 * Since we do the IPI call without holding ctx->lock things can have
213 * changed, double check we hit the task we set out to hit.
216 if (ctx
->task
!= current
) {
222 * We only use event_function_call() on established contexts,
223 * and event_function() is only ever called when active (or
224 * rather, we'll have bailed in task_function_call() or the
225 * above ctx->task != current test), therefore we must have
226 * ctx->is_active here.
228 WARN_ON_ONCE(!ctx
->is_active
);
230 * And since we have ctx->is_active, cpuctx->task_ctx must
233 WARN_ON_ONCE(task_ctx
!= ctx
);
235 WARN_ON_ONCE(&cpuctx
->ctx
!= ctx
);
238 efs
->func(event
, cpuctx
, ctx
, efs
->data
);
240 perf_ctx_unlock(cpuctx
, task_ctx
);
245 static void event_function_call(struct perf_event
*event
, event_f func
, void *data
)
247 struct perf_event_context
*ctx
= event
->ctx
;
248 struct task_struct
*task
= READ_ONCE(ctx
->task
); /* verified in event_function */
249 struct event_function_struct efs
= {
255 if (!event
->parent
) {
257 * If this is a !child event, we must hold ctx::mutex to
258 * stabilize the the event->ctx relation. See
259 * perf_event_ctx_lock().
261 lockdep_assert_held(&ctx
->mutex
);
265 cpu_function_call(event
->cpu
, event_function
, &efs
);
269 if (task
== TASK_TOMBSTONE
)
273 if (!task_function_call(task
, event_function
, &efs
))
276 raw_spin_lock_irq(&ctx
->lock
);
278 * Reload the task pointer, it might have been changed by
279 * a concurrent perf_event_context_sched_out().
282 if (task
== TASK_TOMBSTONE
) {
283 raw_spin_unlock_irq(&ctx
->lock
);
286 if (ctx
->is_active
) {
287 raw_spin_unlock_irq(&ctx
->lock
);
290 func(event
, NULL
, ctx
, data
);
291 raw_spin_unlock_irq(&ctx
->lock
);
295 * Similar to event_function_call() + event_function(), but hard assumes IRQs
296 * are already disabled and we're on the right CPU.
298 static void event_function_local(struct perf_event
*event
, event_f func
, void *data
)
300 struct perf_event_context
*ctx
= event
->ctx
;
301 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
302 struct task_struct
*task
= READ_ONCE(ctx
->task
);
303 struct perf_event_context
*task_ctx
= NULL
;
305 WARN_ON_ONCE(!irqs_disabled());
308 if (task
== TASK_TOMBSTONE
)
314 perf_ctx_lock(cpuctx
, task_ctx
);
317 if (task
== TASK_TOMBSTONE
)
322 * We must be either inactive or active and the right task,
323 * otherwise we're screwed, since we cannot IPI to somewhere
326 if (ctx
->is_active
) {
327 if (WARN_ON_ONCE(task
!= current
))
330 if (WARN_ON_ONCE(cpuctx
->task_ctx
!= ctx
))
334 WARN_ON_ONCE(&cpuctx
->ctx
!= ctx
);
337 func(event
, cpuctx
, ctx
, data
);
339 perf_ctx_unlock(cpuctx
, task_ctx
);
342 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
343 PERF_FLAG_FD_OUTPUT |\
344 PERF_FLAG_PID_CGROUP |\
345 PERF_FLAG_FD_CLOEXEC)
348 * branch priv levels that need permission checks
350 #define PERF_SAMPLE_BRANCH_PERM_PLM \
351 (PERF_SAMPLE_BRANCH_KERNEL |\
352 PERF_SAMPLE_BRANCH_HV)
355 EVENT_FLEXIBLE
= 0x1,
358 EVENT_ALL
= EVENT_FLEXIBLE
| EVENT_PINNED
,
362 * perf_sched_events : >0 events exist
363 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
366 static void perf_sched_delayed(struct work_struct
*work
);
367 DEFINE_STATIC_KEY_FALSE(perf_sched_events
);
368 static DECLARE_DELAYED_WORK(perf_sched_work
, perf_sched_delayed
);
369 static DEFINE_MUTEX(perf_sched_mutex
);
370 static atomic_t perf_sched_count
;
372 static DEFINE_PER_CPU(atomic_t
, perf_cgroup_events
);
373 static DEFINE_PER_CPU(int, perf_sched_cb_usages
);
374 static DEFINE_PER_CPU(struct pmu_event_list
, pmu_sb_events
);
376 static atomic_t nr_mmap_events __read_mostly
;
377 static atomic_t nr_comm_events __read_mostly
;
378 static atomic_t nr_task_events __read_mostly
;
379 static atomic_t nr_freq_events __read_mostly
;
380 static atomic_t nr_switch_events __read_mostly
;
382 static LIST_HEAD(pmus
);
383 static DEFINE_MUTEX(pmus_lock
);
384 static struct srcu_struct pmus_srcu
;
387 * perf event paranoia level:
388 * -1 - not paranoid at all
389 * 0 - disallow raw tracepoint access for unpriv
390 * 1 - disallow cpu events for unpriv
391 * 2 - disallow kernel profiling for unpriv
393 int sysctl_perf_event_paranoid __read_mostly
= 2;
395 /* Minimum for 512 kiB + 1 user control page */
396 int sysctl_perf_event_mlock __read_mostly
= 512 + (PAGE_SIZE
/ 1024); /* 'free' kiB per user */
399 * max perf event sample rate
401 #define DEFAULT_MAX_SAMPLE_RATE 100000
402 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
403 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
405 int sysctl_perf_event_sample_rate __read_mostly
= DEFAULT_MAX_SAMPLE_RATE
;
407 static int max_samples_per_tick __read_mostly
= DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE
, HZ
);
408 static int perf_sample_period_ns __read_mostly
= DEFAULT_SAMPLE_PERIOD_NS
;
410 static int perf_sample_allowed_ns __read_mostly
=
411 DEFAULT_SAMPLE_PERIOD_NS
* DEFAULT_CPU_TIME_MAX_PERCENT
/ 100;
413 static void update_perf_cpu_limits(void)
415 u64 tmp
= perf_sample_period_ns
;
417 tmp
*= sysctl_perf_cpu_time_max_percent
;
418 tmp
= div_u64(tmp
, 100);
422 WRITE_ONCE(perf_sample_allowed_ns
, tmp
);
425 static int perf_rotate_context(struct perf_cpu_context
*cpuctx
);
427 int perf_proc_update_handler(struct ctl_table
*table
, int write
,
428 void __user
*buffer
, size_t *lenp
,
431 int ret
= proc_dointvec_minmax(table
, write
, buffer
, lenp
, ppos
);
437 * If throttling is disabled don't allow the write:
439 if (sysctl_perf_cpu_time_max_percent
== 100 ||
440 sysctl_perf_cpu_time_max_percent
== 0)
443 max_samples_per_tick
= DIV_ROUND_UP(sysctl_perf_event_sample_rate
, HZ
);
444 perf_sample_period_ns
= NSEC_PER_SEC
/ sysctl_perf_event_sample_rate
;
445 update_perf_cpu_limits();
450 int sysctl_perf_cpu_time_max_percent __read_mostly
= DEFAULT_CPU_TIME_MAX_PERCENT
;
452 int perf_cpu_time_max_percent_handler(struct ctl_table
*table
, int write
,
453 void __user
*buffer
, size_t *lenp
,
456 int ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
461 if (sysctl_perf_cpu_time_max_percent
== 100 ||
462 sysctl_perf_cpu_time_max_percent
== 0) {
464 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
465 WRITE_ONCE(perf_sample_allowed_ns
, 0);
467 update_perf_cpu_limits();
474 * perf samples are done in some very critical code paths (NMIs).
475 * If they take too much CPU time, the system can lock up and not
476 * get any real work done. This will drop the sample rate when
477 * we detect that events are taking too long.
479 #define NR_ACCUMULATED_SAMPLES 128
480 static DEFINE_PER_CPU(u64
, running_sample_length
);
482 static u64 __report_avg
;
483 static u64 __report_allowed
;
485 static void perf_duration_warn(struct irq_work
*w
)
487 printk_ratelimited(KERN_INFO
488 "perf: interrupt took too long (%lld > %lld), lowering "
489 "kernel.perf_event_max_sample_rate to %d\n",
490 __report_avg
, __report_allowed
,
491 sysctl_perf_event_sample_rate
);
494 static DEFINE_IRQ_WORK(perf_duration_work
, perf_duration_warn
);
496 void perf_sample_event_took(u64 sample_len_ns
)
498 u64 max_len
= READ_ONCE(perf_sample_allowed_ns
);
506 /* Decay the counter by 1 average sample. */
507 running_len
= __this_cpu_read(running_sample_length
);
508 running_len
-= running_len
/NR_ACCUMULATED_SAMPLES
;
509 running_len
+= sample_len_ns
;
510 __this_cpu_write(running_sample_length
, running_len
);
513 * Note: this will be biased artifically low until we have
514 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
515 * from having to maintain a count.
517 avg_len
= running_len
/NR_ACCUMULATED_SAMPLES
;
518 if (avg_len
<= max_len
)
521 __report_avg
= avg_len
;
522 __report_allowed
= max_len
;
525 * Compute a throttle threshold 25% below the current duration.
527 avg_len
+= avg_len
/ 4;
528 max
= (TICK_NSEC
/ 100) * sysctl_perf_cpu_time_max_percent
;
534 WRITE_ONCE(perf_sample_allowed_ns
, avg_len
);
535 WRITE_ONCE(max_samples_per_tick
, max
);
537 sysctl_perf_event_sample_rate
= max
* HZ
;
538 perf_sample_period_ns
= NSEC_PER_SEC
/ sysctl_perf_event_sample_rate
;
540 if (!irq_work_queue(&perf_duration_work
)) {
541 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
542 "kernel.perf_event_max_sample_rate to %d\n",
543 __report_avg
, __report_allowed
,
544 sysctl_perf_event_sample_rate
);
548 static atomic64_t perf_event_id
;
550 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
551 enum event_type_t event_type
);
553 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
554 enum event_type_t event_type
,
555 struct task_struct
*task
);
557 static void update_context_time(struct perf_event_context
*ctx
);
558 static u64
perf_event_time(struct perf_event
*event
);
560 void __weak
perf_event_print_debug(void) { }
562 extern __weak
const char *perf_pmu_name(void)
567 static inline u64
perf_clock(void)
569 return local_clock();
572 static inline u64
perf_event_clock(struct perf_event
*event
)
574 return event
->clock();
577 #ifdef CONFIG_CGROUP_PERF
580 perf_cgroup_match(struct perf_event
*event
)
582 struct perf_event_context
*ctx
= event
->ctx
;
583 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
585 /* @event doesn't care about cgroup */
589 /* wants specific cgroup scope but @cpuctx isn't associated with any */
594 * Cgroup scoping is recursive. An event enabled for a cgroup is
595 * also enabled for all its descendant cgroups. If @cpuctx's
596 * cgroup is a descendant of @event's (the test covers identity
597 * case), it's a match.
599 return cgroup_is_descendant(cpuctx
->cgrp
->css
.cgroup
,
600 event
->cgrp
->css
.cgroup
);
603 static inline void perf_detach_cgroup(struct perf_event
*event
)
605 css_put(&event
->cgrp
->css
);
609 static inline int is_cgroup_event(struct perf_event
*event
)
611 return event
->cgrp
!= NULL
;
614 static inline u64
perf_cgroup_event_time(struct perf_event
*event
)
616 struct perf_cgroup_info
*t
;
618 t
= per_cpu_ptr(event
->cgrp
->info
, event
->cpu
);
622 static inline void __update_cgrp_time(struct perf_cgroup
*cgrp
)
624 struct perf_cgroup_info
*info
;
629 info
= this_cpu_ptr(cgrp
->info
);
631 info
->time
+= now
- info
->timestamp
;
632 info
->timestamp
= now
;
635 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context
*cpuctx
)
637 struct perf_cgroup
*cgrp_out
= cpuctx
->cgrp
;
639 __update_cgrp_time(cgrp_out
);
642 static inline void update_cgrp_time_from_event(struct perf_event
*event
)
644 struct perf_cgroup
*cgrp
;
647 * ensure we access cgroup data only when needed and
648 * when we know the cgroup is pinned (css_get)
650 if (!is_cgroup_event(event
))
653 cgrp
= perf_cgroup_from_task(current
, event
->ctx
);
655 * Do not update time when cgroup is not active
657 if (cgrp
== event
->cgrp
)
658 __update_cgrp_time(event
->cgrp
);
662 perf_cgroup_set_timestamp(struct task_struct
*task
,
663 struct perf_event_context
*ctx
)
665 struct perf_cgroup
*cgrp
;
666 struct perf_cgroup_info
*info
;
669 * ctx->lock held by caller
670 * ensure we do not access cgroup data
671 * unless we have the cgroup pinned (css_get)
673 if (!task
|| !ctx
->nr_cgroups
)
676 cgrp
= perf_cgroup_from_task(task
, ctx
);
677 info
= this_cpu_ptr(cgrp
->info
);
678 info
->timestamp
= ctx
->timestamp
;
681 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
682 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
685 * reschedule events based on the cgroup constraint of task.
687 * mode SWOUT : schedule out everything
688 * mode SWIN : schedule in based on cgroup for next
690 static void perf_cgroup_switch(struct task_struct
*task
, int mode
)
692 struct perf_cpu_context
*cpuctx
;
697 * disable interrupts to avoid geting nr_cgroup
698 * changes via __perf_event_disable(). Also
701 local_irq_save(flags
);
704 * we reschedule only in the presence of cgroup
705 * constrained events.
708 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
709 cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
710 if (cpuctx
->unique_pmu
!= pmu
)
711 continue; /* ensure we process each cpuctx once */
714 * perf_cgroup_events says at least one
715 * context on this CPU has cgroup events.
717 * ctx->nr_cgroups reports the number of cgroup
718 * events for a context.
720 if (cpuctx
->ctx
.nr_cgroups
> 0) {
721 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
722 perf_pmu_disable(cpuctx
->ctx
.pmu
);
724 if (mode
& PERF_CGROUP_SWOUT
) {
725 cpu_ctx_sched_out(cpuctx
, EVENT_ALL
);
727 * must not be done before ctxswout due
728 * to event_filter_match() in event_sched_out()
733 if (mode
& PERF_CGROUP_SWIN
) {
734 WARN_ON_ONCE(cpuctx
->cgrp
);
736 * set cgrp before ctxsw in to allow
737 * event_filter_match() to not have to pass
739 * we pass the cpuctx->ctx to perf_cgroup_from_task()
740 * because cgorup events are only per-cpu
742 cpuctx
->cgrp
= perf_cgroup_from_task(task
, &cpuctx
->ctx
);
743 cpu_ctx_sched_in(cpuctx
, EVENT_ALL
, task
);
745 perf_pmu_enable(cpuctx
->ctx
.pmu
);
746 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
750 local_irq_restore(flags
);
753 static inline void perf_cgroup_sched_out(struct task_struct
*task
,
754 struct task_struct
*next
)
756 struct perf_cgroup
*cgrp1
;
757 struct perf_cgroup
*cgrp2
= NULL
;
761 * we come here when we know perf_cgroup_events > 0
762 * we do not need to pass the ctx here because we know
763 * we are holding the rcu lock
765 cgrp1
= perf_cgroup_from_task(task
, NULL
);
766 cgrp2
= perf_cgroup_from_task(next
, NULL
);
769 * only schedule out current cgroup events if we know
770 * that we are switching to a different cgroup. Otherwise,
771 * do no touch the cgroup events.
774 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
);
779 static inline void perf_cgroup_sched_in(struct task_struct
*prev
,
780 struct task_struct
*task
)
782 struct perf_cgroup
*cgrp1
;
783 struct perf_cgroup
*cgrp2
= NULL
;
787 * we come here when we know perf_cgroup_events > 0
788 * we do not need to pass the ctx here because we know
789 * we are holding the rcu lock
791 cgrp1
= perf_cgroup_from_task(task
, NULL
);
792 cgrp2
= perf_cgroup_from_task(prev
, NULL
);
795 * only need to schedule in cgroup events if we are changing
796 * cgroup during ctxsw. Cgroup events were not scheduled
797 * out of ctxsw out if that was not the case.
800 perf_cgroup_switch(task
, PERF_CGROUP_SWIN
);
805 static inline int perf_cgroup_connect(int fd
, struct perf_event
*event
,
806 struct perf_event_attr
*attr
,
807 struct perf_event
*group_leader
)
809 struct perf_cgroup
*cgrp
;
810 struct cgroup_subsys_state
*css
;
811 struct fd f
= fdget(fd
);
817 css
= css_tryget_online_from_dir(f
.file
->f_path
.dentry
,
818 &perf_event_cgrp_subsys
);
824 cgrp
= container_of(css
, struct perf_cgroup
, css
);
828 * all events in a group must monitor
829 * the same cgroup because a task belongs
830 * to only one perf cgroup at a time
832 if (group_leader
&& group_leader
->cgrp
!= cgrp
) {
833 perf_detach_cgroup(event
);
842 perf_cgroup_set_shadow_time(struct perf_event
*event
, u64 now
)
844 struct perf_cgroup_info
*t
;
845 t
= per_cpu_ptr(event
->cgrp
->info
, event
->cpu
);
846 event
->shadow_ctx_time
= now
- t
->timestamp
;
850 perf_cgroup_defer_enabled(struct perf_event
*event
)
853 * when the current task's perf cgroup does not match
854 * the event's, we need to remember to call the
855 * perf_mark_enable() function the first time a task with
856 * a matching perf cgroup is scheduled in.
858 if (is_cgroup_event(event
) && !perf_cgroup_match(event
))
859 event
->cgrp_defer_enabled
= 1;
863 perf_cgroup_mark_enabled(struct perf_event
*event
,
864 struct perf_event_context
*ctx
)
866 struct perf_event
*sub
;
867 u64 tstamp
= perf_event_time(event
);
869 if (!event
->cgrp_defer_enabled
)
872 event
->cgrp_defer_enabled
= 0;
874 event
->tstamp_enabled
= tstamp
- event
->total_time_enabled
;
875 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
876 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
) {
877 sub
->tstamp_enabled
= tstamp
- sub
->total_time_enabled
;
878 sub
->cgrp_defer_enabled
= 0;
884 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
885 * cleared when last cgroup event is removed.
888 list_update_cgroup_event(struct perf_event
*event
,
889 struct perf_event_context
*ctx
, bool add
)
891 struct perf_cpu_context
*cpuctx
;
893 if (!is_cgroup_event(event
))
896 if (add
&& ctx
->nr_cgroups
++)
898 else if (!add
&& --ctx
->nr_cgroups
)
901 * Because cgroup events are always per-cpu events,
902 * this will always be called from the right CPU.
904 cpuctx
= __get_cpu_context(ctx
);
907 * cpuctx->cgrp is NULL until a cgroup event is sched in or
908 * ctx->nr_cgroup == 0 .
910 if (add
&& perf_cgroup_from_task(current
, ctx
) == event
->cgrp
)
911 cpuctx
->cgrp
= event
->cgrp
;
916 #else /* !CONFIG_CGROUP_PERF */
919 perf_cgroup_match(struct perf_event
*event
)
924 static inline void perf_detach_cgroup(struct perf_event
*event
)
927 static inline int is_cgroup_event(struct perf_event
*event
)
932 static inline u64
perf_cgroup_event_cgrp_time(struct perf_event
*event
)
937 static inline void update_cgrp_time_from_event(struct perf_event
*event
)
941 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context
*cpuctx
)
945 static inline void perf_cgroup_sched_out(struct task_struct
*task
,
946 struct task_struct
*next
)
950 static inline void perf_cgroup_sched_in(struct task_struct
*prev
,
951 struct task_struct
*task
)
955 static inline int perf_cgroup_connect(pid_t pid
, struct perf_event
*event
,
956 struct perf_event_attr
*attr
,
957 struct perf_event
*group_leader
)
963 perf_cgroup_set_timestamp(struct task_struct
*task
,
964 struct perf_event_context
*ctx
)
969 perf_cgroup_switch(struct task_struct
*task
, struct task_struct
*next
)
974 perf_cgroup_set_shadow_time(struct perf_event
*event
, u64 now
)
978 static inline u64
perf_cgroup_event_time(struct perf_event
*event
)
984 perf_cgroup_defer_enabled(struct perf_event
*event
)
989 perf_cgroup_mark_enabled(struct perf_event
*event
,
990 struct perf_event_context
*ctx
)
995 list_update_cgroup_event(struct perf_event
*event
,
996 struct perf_event_context
*ctx
, bool add
)
1003 * set default to be dependent on timer tick just
1004 * like original code
1006 #define PERF_CPU_HRTIMER (1000 / HZ)
1008 * function must be called with interrupts disbled
1010 static enum hrtimer_restart
perf_mux_hrtimer_handler(struct hrtimer
*hr
)
1012 struct perf_cpu_context
*cpuctx
;
1015 WARN_ON(!irqs_disabled());
1017 cpuctx
= container_of(hr
, struct perf_cpu_context
, hrtimer
);
1018 rotations
= perf_rotate_context(cpuctx
);
1020 raw_spin_lock(&cpuctx
->hrtimer_lock
);
1022 hrtimer_forward_now(hr
, cpuctx
->hrtimer_interval
);
1024 cpuctx
->hrtimer_active
= 0;
1025 raw_spin_unlock(&cpuctx
->hrtimer_lock
);
1027 return rotations
? HRTIMER_RESTART
: HRTIMER_NORESTART
;
1030 static void __perf_mux_hrtimer_init(struct perf_cpu_context
*cpuctx
, int cpu
)
1032 struct hrtimer
*timer
= &cpuctx
->hrtimer
;
1033 struct pmu
*pmu
= cpuctx
->ctx
.pmu
;
1036 /* no multiplexing needed for SW PMU */
1037 if (pmu
->task_ctx_nr
== perf_sw_context
)
1041 * check default is sane, if not set then force to
1042 * default interval (1/tick)
1044 interval
= pmu
->hrtimer_interval_ms
;
1046 interval
= pmu
->hrtimer_interval_ms
= PERF_CPU_HRTIMER
;
1048 cpuctx
->hrtimer_interval
= ns_to_ktime(NSEC_PER_MSEC
* interval
);
1050 raw_spin_lock_init(&cpuctx
->hrtimer_lock
);
1051 hrtimer_init(timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_ABS_PINNED
);
1052 timer
->function
= perf_mux_hrtimer_handler
;
1055 static int perf_mux_hrtimer_restart(struct perf_cpu_context
*cpuctx
)
1057 struct hrtimer
*timer
= &cpuctx
->hrtimer
;
1058 struct pmu
*pmu
= cpuctx
->ctx
.pmu
;
1059 unsigned long flags
;
1061 /* not for SW PMU */
1062 if (pmu
->task_ctx_nr
== perf_sw_context
)
1065 raw_spin_lock_irqsave(&cpuctx
->hrtimer_lock
, flags
);
1066 if (!cpuctx
->hrtimer_active
) {
1067 cpuctx
->hrtimer_active
= 1;
1068 hrtimer_forward_now(timer
, cpuctx
->hrtimer_interval
);
1069 hrtimer_start_expires(timer
, HRTIMER_MODE_ABS_PINNED
);
1071 raw_spin_unlock_irqrestore(&cpuctx
->hrtimer_lock
, flags
);
1076 void perf_pmu_disable(struct pmu
*pmu
)
1078 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
1080 pmu
->pmu_disable(pmu
);
1083 void perf_pmu_enable(struct pmu
*pmu
)
1085 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
1087 pmu
->pmu_enable(pmu
);
1090 static DEFINE_PER_CPU(struct list_head
, active_ctx_list
);
1093 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1094 * perf_event_task_tick() are fully serialized because they're strictly cpu
1095 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1096 * disabled, while perf_event_task_tick is called from IRQ context.
1098 static void perf_event_ctx_activate(struct perf_event_context
*ctx
)
1100 struct list_head
*head
= this_cpu_ptr(&active_ctx_list
);
1102 WARN_ON(!irqs_disabled());
1104 WARN_ON(!list_empty(&ctx
->active_ctx_list
));
1106 list_add(&ctx
->active_ctx_list
, head
);
1109 static void perf_event_ctx_deactivate(struct perf_event_context
*ctx
)
1111 WARN_ON(!irqs_disabled());
1113 WARN_ON(list_empty(&ctx
->active_ctx_list
));
1115 list_del_init(&ctx
->active_ctx_list
);
1118 static void get_ctx(struct perf_event_context
*ctx
)
1120 WARN_ON(!atomic_inc_not_zero(&ctx
->refcount
));
1123 static void free_ctx(struct rcu_head
*head
)
1125 struct perf_event_context
*ctx
;
1127 ctx
= container_of(head
, struct perf_event_context
, rcu_head
);
1128 kfree(ctx
->task_ctx_data
);
1132 static void put_ctx(struct perf_event_context
*ctx
)
1134 if (atomic_dec_and_test(&ctx
->refcount
)) {
1135 if (ctx
->parent_ctx
)
1136 put_ctx(ctx
->parent_ctx
);
1137 if (ctx
->task
&& ctx
->task
!= TASK_TOMBSTONE
)
1138 put_task_struct(ctx
->task
);
1139 call_rcu(&ctx
->rcu_head
, free_ctx
);
1144 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1145 * perf_pmu_migrate_context() we need some magic.
1147 * Those places that change perf_event::ctx will hold both
1148 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1150 * Lock ordering is by mutex address. There are two other sites where
1151 * perf_event_context::mutex nests and those are:
1153 * - perf_event_exit_task_context() [ child , 0 ]
1154 * perf_event_exit_event()
1155 * put_event() [ parent, 1 ]
1157 * - perf_event_init_context() [ parent, 0 ]
1158 * inherit_task_group()
1161 * perf_event_alloc()
1163 * perf_try_init_event() [ child , 1 ]
1165 * While it appears there is an obvious deadlock here -- the parent and child
1166 * nesting levels are inverted between the two. This is in fact safe because
1167 * life-time rules separate them. That is an exiting task cannot fork, and a
1168 * spawning task cannot (yet) exit.
1170 * But remember that that these are parent<->child context relations, and
1171 * migration does not affect children, therefore these two orderings should not
1174 * The change in perf_event::ctx does not affect children (as claimed above)
1175 * because the sys_perf_event_open() case will install a new event and break
1176 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1177 * concerned with cpuctx and that doesn't have children.
1179 * The places that change perf_event::ctx will issue:
1181 * perf_remove_from_context();
1182 * synchronize_rcu();
1183 * perf_install_in_context();
1185 * to affect the change. The remove_from_context() + synchronize_rcu() should
1186 * quiesce the event, after which we can install it in the new location. This
1187 * means that only external vectors (perf_fops, prctl) can perturb the event
1188 * while in transit. Therefore all such accessors should also acquire
1189 * perf_event_context::mutex to serialize against this.
1191 * However; because event->ctx can change while we're waiting to acquire
1192 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1197 * task_struct::perf_event_mutex
1198 * perf_event_context::mutex
1199 * perf_event::child_mutex;
1200 * perf_event_context::lock
1201 * perf_event::mmap_mutex
1204 static struct perf_event_context
*
1205 perf_event_ctx_lock_nested(struct perf_event
*event
, int nesting
)
1207 struct perf_event_context
*ctx
;
1211 ctx
= ACCESS_ONCE(event
->ctx
);
1212 if (!atomic_inc_not_zero(&ctx
->refcount
)) {
1218 mutex_lock_nested(&ctx
->mutex
, nesting
);
1219 if (event
->ctx
!= ctx
) {
1220 mutex_unlock(&ctx
->mutex
);
1228 static inline struct perf_event_context
*
1229 perf_event_ctx_lock(struct perf_event
*event
)
1231 return perf_event_ctx_lock_nested(event
, 0);
1234 static void perf_event_ctx_unlock(struct perf_event
*event
,
1235 struct perf_event_context
*ctx
)
1237 mutex_unlock(&ctx
->mutex
);
1242 * This must be done under the ctx->lock, such as to serialize against
1243 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1244 * calling scheduler related locks and ctx->lock nests inside those.
1246 static __must_check
struct perf_event_context
*
1247 unclone_ctx(struct perf_event_context
*ctx
)
1249 struct perf_event_context
*parent_ctx
= ctx
->parent_ctx
;
1251 lockdep_assert_held(&ctx
->lock
);
1254 ctx
->parent_ctx
= NULL
;
1260 static u32
perf_event_pid(struct perf_event
*event
, struct task_struct
*p
)
1263 * only top level events have the pid namespace they were created in
1266 event
= event
->parent
;
1268 return task_tgid_nr_ns(p
, event
->ns
);
1271 static u32
perf_event_tid(struct perf_event
*event
, struct task_struct
*p
)
1274 * only top level events have the pid namespace they were created in
1277 event
= event
->parent
;
1279 return task_pid_nr_ns(p
, event
->ns
);
1283 * If we inherit events we want to return the parent event id
1286 static u64
primary_event_id(struct perf_event
*event
)
1291 id
= event
->parent
->id
;
1297 * Get the perf_event_context for a task and lock it.
1299 * This has to cope with with the fact that until it is locked,
1300 * the context could get moved to another task.
1302 static struct perf_event_context
*
1303 perf_lock_task_context(struct task_struct
*task
, int ctxn
, unsigned long *flags
)
1305 struct perf_event_context
*ctx
;
1309 * One of the few rules of preemptible RCU is that one cannot do
1310 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1311 * part of the read side critical section was irqs-enabled -- see
1312 * rcu_read_unlock_special().
1314 * Since ctx->lock nests under rq->lock we must ensure the entire read
1315 * side critical section has interrupts disabled.
1317 local_irq_save(*flags
);
1319 ctx
= rcu_dereference(task
->perf_event_ctxp
[ctxn
]);
1322 * If this context is a clone of another, it might
1323 * get swapped for another underneath us by
1324 * perf_event_task_sched_out, though the
1325 * rcu_read_lock() protects us from any context
1326 * getting freed. Lock the context and check if it
1327 * got swapped before we could get the lock, and retry
1328 * if so. If we locked the right context, then it
1329 * can't get swapped on us any more.
1331 raw_spin_lock(&ctx
->lock
);
1332 if (ctx
!= rcu_dereference(task
->perf_event_ctxp
[ctxn
])) {
1333 raw_spin_unlock(&ctx
->lock
);
1335 local_irq_restore(*flags
);
1339 if (ctx
->task
== TASK_TOMBSTONE
||
1340 !atomic_inc_not_zero(&ctx
->refcount
)) {
1341 raw_spin_unlock(&ctx
->lock
);
1344 WARN_ON_ONCE(ctx
->task
!= task
);
1349 local_irq_restore(*flags
);
1354 * Get the context for a task and increment its pin_count so it
1355 * can't get swapped to another task. This also increments its
1356 * reference count so that the context can't get freed.
1358 static struct perf_event_context
*
1359 perf_pin_task_context(struct task_struct
*task
, int ctxn
)
1361 struct perf_event_context
*ctx
;
1362 unsigned long flags
;
1364 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
1367 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1372 static void perf_unpin_context(struct perf_event_context
*ctx
)
1374 unsigned long flags
;
1376 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
1378 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1382 * Update the record of the current time in a context.
1384 static void update_context_time(struct perf_event_context
*ctx
)
1386 u64 now
= perf_clock();
1388 ctx
->time
+= now
- ctx
->timestamp
;
1389 ctx
->timestamp
= now
;
1392 static u64
perf_event_time(struct perf_event
*event
)
1394 struct perf_event_context
*ctx
= event
->ctx
;
1396 if (is_cgroup_event(event
))
1397 return perf_cgroup_event_time(event
);
1399 return ctx
? ctx
->time
: 0;
1403 * Update the total_time_enabled and total_time_running fields for a event.
1405 static void update_event_times(struct perf_event
*event
)
1407 struct perf_event_context
*ctx
= event
->ctx
;
1410 lockdep_assert_held(&ctx
->lock
);
1412 if (event
->state
< PERF_EVENT_STATE_INACTIVE
||
1413 event
->group_leader
->state
< PERF_EVENT_STATE_INACTIVE
)
1417 * in cgroup mode, time_enabled represents
1418 * the time the event was enabled AND active
1419 * tasks were in the monitored cgroup. This is
1420 * independent of the activity of the context as
1421 * there may be a mix of cgroup and non-cgroup events.
1423 * That is why we treat cgroup events differently
1426 if (is_cgroup_event(event
))
1427 run_end
= perf_cgroup_event_time(event
);
1428 else if (ctx
->is_active
)
1429 run_end
= ctx
->time
;
1431 run_end
= event
->tstamp_stopped
;
1433 event
->total_time_enabled
= run_end
- event
->tstamp_enabled
;
1435 if (event
->state
== PERF_EVENT_STATE_INACTIVE
)
1436 run_end
= event
->tstamp_stopped
;
1438 run_end
= perf_event_time(event
);
1440 event
->total_time_running
= run_end
- event
->tstamp_running
;
1445 * Update total_time_enabled and total_time_running for all events in a group.
1447 static void update_group_times(struct perf_event
*leader
)
1449 struct perf_event
*event
;
1451 update_event_times(leader
);
1452 list_for_each_entry(event
, &leader
->sibling_list
, group_entry
)
1453 update_event_times(event
);
1456 static struct list_head
*
1457 ctx_group_list(struct perf_event
*event
, struct perf_event_context
*ctx
)
1459 if (event
->attr
.pinned
)
1460 return &ctx
->pinned_groups
;
1462 return &ctx
->flexible_groups
;
1466 * Add a event from the lists for its context.
1467 * Must be called with ctx->mutex and ctx->lock held.
1470 list_add_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
1472 lockdep_assert_held(&ctx
->lock
);
1474 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_CONTEXT
);
1475 event
->attach_state
|= PERF_ATTACH_CONTEXT
;
1478 * If we're a stand alone event or group leader, we go to the context
1479 * list, group events are kept attached to the group so that
1480 * perf_group_detach can, at all times, locate all siblings.
1482 if (event
->group_leader
== event
) {
1483 struct list_head
*list
;
1485 event
->group_caps
= event
->event_caps
;
1487 list
= ctx_group_list(event
, ctx
);
1488 list_add_tail(&event
->group_entry
, list
);
1491 list_update_cgroup_event(event
, ctx
, true);
1493 list_add_rcu(&event
->event_entry
, &ctx
->event_list
);
1495 if (event
->attr
.inherit_stat
)
1502 * Initialize event state based on the perf_event_attr::disabled.
1504 static inline void perf_event__state_init(struct perf_event
*event
)
1506 event
->state
= event
->attr
.disabled
? PERF_EVENT_STATE_OFF
:
1507 PERF_EVENT_STATE_INACTIVE
;
1510 static void __perf_event_read_size(struct perf_event
*event
, int nr_siblings
)
1512 int entry
= sizeof(u64
); /* value */
1516 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1517 size
+= sizeof(u64
);
1519 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1520 size
+= sizeof(u64
);
1522 if (event
->attr
.read_format
& PERF_FORMAT_ID
)
1523 entry
+= sizeof(u64
);
1525 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
) {
1527 size
+= sizeof(u64
);
1531 event
->read_size
= size
;
1534 static void __perf_event_header_size(struct perf_event
*event
, u64 sample_type
)
1536 struct perf_sample_data
*data
;
1539 if (sample_type
& PERF_SAMPLE_IP
)
1540 size
+= sizeof(data
->ip
);
1542 if (sample_type
& PERF_SAMPLE_ADDR
)
1543 size
+= sizeof(data
->addr
);
1545 if (sample_type
& PERF_SAMPLE_PERIOD
)
1546 size
+= sizeof(data
->period
);
1548 if (sample_type
& PERF_SAMPLE_WEIGHT
)
1549 size
+= sizeof(data
->weight
);
1551 if (sample_type
& PERF_SAMPLE_READ
)
1552 size
+= event
->read_size
;
1554 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
1555 size
+= sizeof(data
->data_src
.val
);
1557 if (sample_type
& PERF_SAMPLE_TRANSACTION
)
1558 size
+= sizeof(data
->txn
);
1560 event
->header_size
= size
;
1564 * Called at perf_event creation and when events are attached/detached from a
1567 static void perf_event__header_size(struct perf_event
*event
)
1569 __perf_event_read_size(event
,
1570 event
->group_leader
->nr_siblings
);
1571 __perf_event_header_size(event
, event
->attr
.sample_type
);
1574 static void perf_event__id_header_size(struct perf_event
*event
)
1576 struct perf_sample_data
*data
;
1577 u64 sample_type
= event
->attr
.sample_type
;
1580 if (sample_type
& PERF_SAMPLE_TID
)
1581 size
+= sizeof(data
->tid_entry
);
1583 if (sample_type
& PERF_SAMPLE_TIME
)
1584 size
+= sizeof(data
->time
);
1586 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
1587 size
+= sizeof(data
->id
);
1589 if (sample_type
& PERF_SAMPLE_ID
)
1590 size
+= sizeof(data
->id
);
1592 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
1593 size
+= sizeof(data
->stream_id
);
1595 if (sample_type
& PERF_SAMPLE_CPU
)
1596 size
+= sizeof(data
->cpu_entry
);
1598 event
->id_header_size
= size
;
1601 static bool perf_event_validate_size(struct perf_event
*event
)
1604 * The values computed here will be over-written when we actually
1607 __perf_event_read_size(event
, event
->group_leader
->nr_siblings
+ 1);
1608 __perf_event_header_size(event
, event
->attr
.sample_type
& ~PERF_SAMPLE_READ
);
1609 perf_event__id_header_size(event
);
1612 * Sum the lot; should not exceed the 64k limit we have on records.
1613 * Conservative limit to allow for callchains and other variable fields.
1615 if (event
->read_size
+ event
->header_size
+
1616 event
->id_header_size
+ sizeof(struct perf_event_header
) >= 16*1024)
1622 static void perf_group_attach(struct perf_event
*event
)
1624 struct perf_event
*group_leader
= event
->group_leader
, *pos
;
1626 lockdep_assert_held(&event
->ctx
->lock
);
1629 * We can have double attach due to group movement in perf_event_open.
1631 if (event
->attach_state
& PERF_ATTACH_GROUP
)
1634 event
->attach_state
|= PERF_ATTACH_GROUP
;
1636 if (group_leader
== event
)
1639 WARN_ON_ONCE(group_leader
->ctx
!= event
->ctx
);
1641 group_leader
->group_caps
&= event
->event_caps
;
1643 list_add_tail(&event
->group_entry
, &group_leader
->sibling_list
);
1644 group_leader
->nr_siblings
++;
1646 perf_event__header_size(group_leader
);
1648 list_for_each_entry(pos
, &group_leader
->sibling_list
, group_entry
)
1649 perf_event__header_size(pos
);
1653 * Remove a event from the lists for its context.
1654 * Must be called with ctx->mutex and ctx->lock held.
1657 list_del_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
1659 WARN_ON_ONCE(event
->ctx
!= ctx
);
1660 lockdep_assert_held(&ctx
->lock
);
1663 * We can have double detach due to exit/hot-unplug + close.
1665 if (!(event
->attach_state
& PERF_ATTACH_CONTEXT
))
1668 event
->attach_state
&= ~PERF_ATTACH_CONTEXT
;
1670 list_update_cgroup_event(event
, ctx
, false);
1673 if (event
->attr
.inherit_stat
)
1676 list_del_rcu(&event
->event_entry
);
1678 if (event
->group_leader
== event
)
1679 list_del_init(&event
->group_entry
);
1681 update_group_times(event
);
1684 * If event was in error state, then keep it
1685 * that way, otherwise bogus counts will be
1686 * returned on read(). The only way to get out
1687 * of error state is by explicit re-enabling
1690 if (event
->state
> PERF_EVENT_STATE_OFF
)
1691 event
->state
= PERF_EVENT_STATE_OFF
;
1696 static void perf_group_detach(struct perf_event
*event
)
1698 struct perf_event
*sibling
, *tmp
;
1699 struct list_head
*list
= NULL
;
1701 lockdep_assert_held(&event
->ctx
->lock
);
1704 * We can have double detach due to exit/hot-unplug + close.
1706 if (!(event
->attach_state
& PERF_ATTACH_GROUP
))
1709 event
->attach_state
&= ~PERF_ATTACH_GROUP
;
1712 * If this is a sibling, remove it from its group.
1714 if (event
->group_leader
!= event
) {
1715 list_del_init(&event
->group_entry
);
1716 event
->group_leader
->nr_siblings
--;
1720 if (!list_empty(&event
->group_entry
))
1721 list
= &event
->group_entry
;
1724 * If this was a group event with sibling events then
1725 * upgrade the siblings to singleton events by adding them
1726 * to whatever list we are on.
1728 list_for_each_entry_safe(sibling
, tmp
, &event
->sibling_list
, group_entry
) {
1730 list_move_tail(&sibling
->group_entry
, list
);
1731 sibling
->group_leader
= sibling
;
1733 /* Inherit group flags from the previous leader */
1734 sibling
->group_caps
= event
->group_caps
;
1736 WARN_ON_ONCE(sibling
->ctx
!= event
->ctx
);
1740 perf_event__header_size(event
->group_leader
);
1742 list_for_each_entry(tmp
, &event
->group_leader
->sibling_list
, group_entry
)
1743 perf_event__header_size(tmp
);
1746 static bool is_orphaned_event(struct perf_event
*event
)
1748 return event
->state
== PERF_EVENT_STATE_DEAD
;
1751 static inline int __pmu_filter_match(struct perf_event
*event
)
1753 struct pmu
*pmu
= event
->pmu
;
1754 return pmu
->filter_match
? pmu
->filter_match(event
) : 1;
1758 * Check whether we should attempt to schedule an event group based on
1759 * PMU-specific filtering. An event group can consist of HW and SW events,
1760 * potentially with a SW leader, so we must check all the filters, to
1761 * determine whether a group is schedulable:
1763 static inline int pmu_filter_match(struct perf_event
*event
)
1765 struct perf_event
*child
;
1767 if (!__pmu_filter_match(event
))
1770 list_for_each_entry(child
, &event
->sibling_list
, group_entry
) {
1771 if (!__pmu_filter_match(child
))
1779 event_filter_match(struct perf_event
*event
)
1781 return (event
->cpu
== -1 || event
->cpu
== smp_processor_id()) &&
1782 perf_cgroup_match(event
) && pmu_filter_match(event
);
1786 event_sched_out(struct perf_event
*event
,
1787 struct perf_cpu_context
*cpuctx
,
1788 struct perf_event_context
*ctx
)
1790 u64 tstamp
= perf_event_time(event
);
1793 WARN_ON_ONCE(event
->ctx
!= ctx
);
1794 lockdep_assert_held(&ctx
->lock
);
1797 * An event which could not be activated because of
1798 * filter mismatch still needs to have its timings
1799 * maintained, otherwise bogus information is return
1800 * via read() for time_enabled, time_running:
1802 if (event
->state
== PERF_EVENT_STATE_INACTIVE
&&
1803 !event_filter_match(event
)) {
1804 delta
= tstamp
- event
->tstamp_stopped
;
1805 event
->tstamp_running
+= delta
;
1806 event
->tstamp_stopped
= tstamp
;
1809 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
1812 perf_pmu_disable(event
->pmu
);
1814 event
->tstamp_stopped
= tstamp
;
1815 event
->pmu
->del(event
, 0);
1817 event
->state
= PERF_EVENT_STATE_INACTIVE
;
1818 if (event
->pending_disable
) {
1819 event
->pending_disable
= 0;
1820 event
->state
= PERF_EVENT_STATE_OFF
;
1823 if (!is_software_event(event
))
1824 cpuctx
->active_oncpu
--;
1825 if (!--ctx
->nr_active
)
1826 perf_event_ctx_deactivate(ctx
);
1827 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
1829 if (event
->attr
.exclusive
|| !cpuctx
->active_oncpu
)
1830 cpuctx
->exclusive
= 0;
1832 perf_pmu_enable(event
->pmu
);
1836 group_sched_out(struct perf_event
*group_event
,
1837 struct perf_cpu_context
*cpuctx
,
1838 struct perf_event_context
*ctx
)
1840 struct perf_event
*event
;
1841 int state
= group_event
->state
;
1843 perf_pmu_disable(ctx
->pmu
);
1845 event_sched_out(group_event
, cpuctx
, ctx
);
1848 * Schedule out siblings (if any):
1850 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
)
1851 event_sched_out(event
, cpuctx
, ctx
);
1853 perf_pmu_enable(ctx
->pmu
);
1855 if (state
== PERF_EVENT_STATE_ACTIVE
&& group_event
->attr
.exclusive
)
1856 cpuctx
->exclusive
= 0;
1859 #define DETACH_GROUP 0x01UL
1862 * Cross CPU call to remove a performance event
1864 * We disable the event on the hardware level first. After that we
1865 * remove it from the context list.
1868 __perf_remove_from_context(struct perf_event
*event
,
1869 struct perf_cpu_context
*cpuctx
,
1870 struct perf_event_context
*ctx
,
1873 unsigned long flags
= (unsigned long)info
;
1875 event_sched_out(event
, cpuctx
, ctx
);
1876 if (flags
& DETACH_GROUP
)
1877 perf_group_detach(event
);
1878 list_del_event(event
, ctx
);
1880 if (!ctx
->nr_events
&& ctx
->is_active
) {
1883 WARN_ON_ONCE(cpuctx
->task_ctx
!= ctx
);
1884 cpuctx
->task_ctx
= NULL
;
1890 * Remove the event from a task's (or a CPU's) list of events.
1892 * If event->ctx is a cloned context, callers must make sure that
1893 * every task struct that event->ctx->task could possibly point to
1894 * remains valid. This is OK when called from perf_release since
1895 * that only calls us on the top-level context, which can't be a clone.
1896 * When called from perf_event_exit_task, it's OK because the
1897 * context has been detached from its task.
1899 static void perf_remove_from_context(struct perf_event
*event
, unsigned long flags
)
1901 struct perf_event_context
*ctx
= event
->ctx
;
1903 lockdep_assert_held(&ctx
->mutex
);
1905 event_function_call(event
, __perf_remove_from_context
, (void *)flags
);
1908 * The above event_function_call() can NO-OP when it hits
1909 * TASK_TOMBSTONE. In that case we must already have been detached
1910 * from the context (by perf_event_exit_event()) but the grouping
1911 * might still be in-tact.
1913 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_CONTEXT
);
1914 if ((flags
& DETACH_GROUP
) &&
1915 (event
->attach_state
& PERF_ATTACH_GROUP
)) {
1917 * Since in that case we cannot possibly be scheduled, simply
1920 raw_spin_lock_irq(&ctx
->lock
);
1921 perf_group_detach(event
);
1922 raw_spin_unlock_irq(&ctx
->lock
);
1927 * Cross CPU call to disable a performance event
1929 static void __perf_event_disable(struct perf_event
*event
,
1930 struct perf_cpu_context
*cpuctx
,
1931 struct perf_event_context
*ctx
,
1934 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
1937 update_context_time(ctx
);
1938 update_cgrp_time_from_event(event
);
1939 update_group_times(event
);
1940 if (event
== event
->group_leader
)
1941 group_sched_out(event
, cpuctx
, ctx
);
1943 event_sched_out(event
, cpuctx
, ctx
);
1944 event
->state
= PERF_EVENT_STATE_OFF
;
1950 * If event->ctx is a cloned context, callers must make sure that
1951 * every task struct that event->ctx->task could possibly point to
1952 * remains valid. This condition is satisifed when called through
1953 * perf_event_for_each_child or perf_event_for_each because they
1954 * hold the top-level event's child_mutex, so any descendant that
1955 * goes to exit will block in perf_event_exit_event().
1957 * When called from perf_pending_event it's OK because event->ctx
1958 * is the current context on this CPU and preemption is disabled,
1959 * hence we can't get into perf_event_task_sched_out for this context.
1961 static void _perf_event_disable(struct perf_event
*event
)
1963 struct perf_event_context
*ctx
= event
->ctx
;
1965 raw_spin_lock_irq(&ctx
->lock
);
1966 if (event
->state
<= PERF_EVENT_STATE_OFF
) {
1967 raw_spin_unlock_irq(&ctx
->lock
);
1970 raw_spin_unlock_irq(&ctx
->lock
);
1972 event_function_call(event
, __perf_event_disable
, NULL
);
1975 void perf_event_disable_local(struct perf_event
*event
)
1977 event_function_local(event
, __perf_event_disable
, NULL
);
1981 * Strictly speaking kernel users cannot create groups and therefore this
1982 * interface does not need the perf_event_ctx_lock() magic.
1984 void perf_event_disable(struct perf_event
*event
)
1986 struct perf_event_context
*ctx
;
1988 ctx
= perf_event_ctx_lock(event
);
1989 _perf_event_disable(event
);
1990 perf_event_ctx_unlock(event
, ctx
);
1992 EXPORT_SYMBOL_GPL(perf_event_disable
);
1994 void perf_event_disable_inatomic(struct perf_event
*event
)
1996 event
->pending_disable
= 1;
1997 irq_work_queue(&event
->pending
);
2000 static void perf_set_shadow_time(struct perf_event
*event
,
2001 struct perf_event_context
*ctx
,
2005 * use the correct time source for the time snapshot
2007 * We could get by without this by leveraging the
2008 * fact that to get to this function, the caller
2009 * has most likely already called update_context_time()
2010 * and update_cgrp_time_xx() and thus both timestamp
2011 * are identical (or very close). Given that tstamp is,
2012 * already adjusted for cgroup, we could say that:
2013 * tstamp - ctx->timestamp
2015 * tstamp - cgrp->timestamp.
2017 * Then, in perf_output_read(), the calculation would
2018 * work with no changes because:
2019 * - event is guaranteed scheduled in
2020 * - no scheduled out in between
2021 * - thus the timestamp would be the same
2023 * But this is a bit hairy.
2025 * So instead, we have an explicit cgroup call to remain
2026 * within the time time source all along. We believe it
2027 * is cleaner and simpler to understand.
2029 if (is_cgroup_event(event
))
2030 perf_cgroup_set_shadow_time(event
, tstamp
);
2032 event
->shadow_ctx_time
= tstamp
- ctx
->timestamp
;
2035 #define MAX_INTERRUPTS (~0ULL)
2037 static void perf_log_throttle(struct perf_event
*event
, int enable
);
2038 static void perf_log_itrace_start(struct perf_event
*event
);
2041 event_sched_in(struct perf_event
*event
,
2042 struct perf_cpu_context
*cpuctx
,
2043 struct perf_event_context
*ctx
)
2045 u64 tstamp
= perf_event_time(event
);
2048 lockdep_assert_held(&ctx
->lock
);
2050 if (event
->state
<= PERF_EVENT_STATE_OFF
)
2053 WRITE_ONCE(event
->oncpu
, smp_processor_id());
2055 * Order event::oncpu write to happen before the ACTIVE state
2059 WRITE_ONCE(event
->state
, PERF_EVENT_STATE_ACTIVE
);
2062 * Unthrottle events, since we scheduled we might have missed several
2063 * ticks already, also for a heavily scheduling task there is little
2064 * guarantee it'll get a tick in a timely manner.
2066 if (unlikely(event
->hw
.interrupts
== MAX_INTERRUPTS
)) {
2067 perf_log_throttle(event
, 1);
2068 event
->hw
.interrupts
= 0;
2072 * The new state must be visible before we turn it on in the hardware:
2076 perf_pmu_disable(event
->pmu
);
2078 perf_set_shadow_time(event
, ctx
, tstamp
);
2080 perf_log_itrace_start(event
);
2082 if (event
->pmu
->add(event
, PERF_EF_START
)) {
2083 event
->state
= PERF_EVENT_STATE_INACTIVE
;
2089 event
->tstamp_running
+= tstamp
- event
->tstamp_stopped
;
2091 if (!is_software_event(event
))
2092 cpuctx
->active_oncpu
++;
2093 if (!ctx
->nr_active
++)
2094 perf_event_ctx_activate(ctx
);
2095 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
2098 if (event
->attr
.exclusive
)
2099 cpuctx
->exclusive
= 1;
2102 perf_pmu_enable(event
->pmu
);
2108 group_sched_in(struct perf_event
*group_event
,
2109 struct perf_cpu_context
*cpuctx
,
2110 struct perf_event_context
*ctx
)
2112 struct perf_event
*event
, *partial_group
= NULL
;
2113 struct pmu
*pmu
= ctx
->pmu
;
2114 u64 now
= ctx
->time
;
2115 bool simulate
= false;
2117 if (group_event
->state
== PERF_EVENT_STATE_OFF
)
2120 pmu
->start_txn(pmu
, PERF_PMU_TXN_ADD
);
2122 if (event_sched_in(group_event
, cpuctx
, ctx
)) {
2123 pmu
->cancel_txn(pmu
);
2124 perf_mux_hrtimer_restart(cpuctx
);
2129 * Schedule in siblings as one group (if any):
2131 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
2132 if (event_sched_in(event
, cpuctx
, ctx
)) {
2133 partial_group
= event
;
2138 if (!pmu
->commit_txn(pmu
))
2143 * Groups can be scheduled in as one unit only, so undo any
2144 * partial group before returning:
2145 * The events up to the failed event are scheduled out normally,
2146 * tstamp_stopped will be updated.
2148 * The failed events and the remaining siblings need to have
2149 * their timings updated as if they had gone thru event_sched_in()
2150 * and event_sched_out(). This is required to get consistent timings
2151 * across the group. This also takes care of the case where the group
2152 * could never be scheduled by ensuring tstamp_stopped is set to mark
2153 * the time the event was actually stopped, such that time delta
2154 * calculation in update_event_times() is correct.
2156 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
2157 if (event
== partial_group
)
2161 event
->tstamp_running
+= now
- event
->tstamp_stopped
;
2162 event
->tstamp_stopped
= now
;
2164 event_sched_out(event
, cpuctx
, ctx
);
2167 event_sched_out(group_event
, cpuctx
, ctx
);
2169 pmu
->cancel_txn(pmu
);
2171 perf_mux_hrtimer_restart(cpuctx
);
2177 * Work out whether we can put this event group on the CPU now.
2179 static int group_can_go_on(struct perf_event
*event
,
2180 struct perf_cpu_context
*cpuctx
,
2184 * Groups consisting entirely of software events can always go on.
2186 if (event
->group_caps
& PERF_EV_CAP_SOFTWARE
)
2189 * If an exclusive group is already on, no other hardware
2192 if (cpuctx
->exclusive
)
2195 * If this group is exclusive and there are already
2196 * events on the CPU, it can't go on.
2198 if (event
->attr
.exclusive
&& cpuctx
->active_oncpu
)
2201 * Otherwise, try to add it if all previous groups were able
2207 static void add_event_to_ctx(struct perf_event
*event
,
2208 struct perf_event_context
*ctx
)
2210 u64 tstamp
= perf_event_time(event
);
2212 list_add_event(event
, ctx
);
2213 perf_group_attach(event
);
2214 event
->tstamp_enabled
= tstamp
;
2215 event
->tstamp_running
= tstamp
;
2216 event
->tstamp_stopped
= tstamp
;
2219 static void ctx_sched_out(struct perf_event_context
*ctx
,
2220 struct perf_cpu_context
*cpuctx
,
2221 enum event_type_t event_type
);
2223 ctx_sched_in(struct perf_event_context
*ctx
,
2224 struct perf_cpu_context
*cpuctx
,
2225 enum event_type_t event_type
,
2226 struct task_struct
*task
);
2228 static void task_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
2229 struct perf_event_context
*ctx
)
2231 if (!cpuctx
->task_ctx
)
2234 if (WARN_ON_ONCE(ctx
!= cpuctx
->task_ctx
))
2237 ctx_sched_out(ctx
, cpuctx
, EVENT_ALL
);
2240 static void perf_event_sched_in(struct perf_cpu_context
*cpuctx
,
2241 struct perf_event_context
*ctx
,
2242 struct task_struct
*task
)
2244 cpu_ctx_sched_in(cpuctx
, EVENT_PINNED
, task
);
2246 ctx_sched_in(ctx
, cpuctx
, EVENT_PINNED
, task
);
2247 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
, task
);
2249 ctx_sched_in(ctx
, cpuctx
, EVENT_FLEXIBLE
, task
);
2252 static void ctx_resched(struct perf_cpu_context
*cpuctx
,
2253 struct perf_event_context
*task_ctx
)
2255 perf_pmu_disable(cpuctx
->ctx
.pmu
);
2257 task_ctx_sched_out(cpuctx
, task_ctx
);
2258 cpu_ctx_sched_out(cpuctx
, EVENT_ALL
);
2259 perf_event_sched_in(cpuctx
, task_ctx
, current
);
2260 perf_pmu_enable(cpuctx
->ctx
.pmu
);
2264 * Cross CPU call to install and enable a performance event
2266 * Very similar to remote_function() + event_function() but cannot assume that
2267 * things like ctx->is_active and cpuctx->task_ctx are set.
2269 static int __perf_install_in_context(void *info
)
2271 struct perf_event
*event
= info
;
2272 struct perf_event_context
*ctx
= event
->ctx
;
2273 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
2274 struct perf_event_context
*task_ctx
= cpuctx
->task_ctx
;
2275 bool reprogram
= true;
2278 raw_spin_lock(&cpuctx
->ctx
.lock
);
2280 raw_spin_lock(&ctx
->lock
);
2283 reprogram
= (ctx
->task
== current
);
2286 * If the task is running, it must be running on this CPU,
2287 * otherwise we cannot reprogram things.
2289 * If its not running, we don't care, ctx->lock will
2290 * serialize against it becoming runnable.
2292 if (task_curr(ctx
->task
) && !reprogram
) {
2297 WARN_ON_ONCE(reprogram
&& cpuctx
->task_ctx
&& cpuctx
->task_ctx
!= ctx
);
2298 } else if (task_ctx
) {
2299 raw_spin_lock(&task_ctx
->lock
);
2303 ctx_sched_out(ctx
, cpuctx
, EVENT_TIME
);
2304 add_event_to_ctx(event
, ctx
);
2305 ctx_resched(cpuctx
, task_ctx
);
2307 add_event_to_ctx(event
, ctx
);
2311 perf_ctx_unlock(cpuctx
, task_ctx
);
2317 * Attach a performance event to a context.
2319 * Very similar to event_function_call, see comment there.
2322 perf_install_in_context(struct perf_event_context
*ctx
,
2323 struct perf_event
*event
,
2326 struct task_struct
*task
= READ_ONCE(ctx
->task
);
2328 lockdep_assert_held(&ctx
->mutex
);
2330 if (event
->cpu
!= -1)
2334 * Ensures that if we can observe event->ctx, both the event and ctx
2335 * will be 'complete'. See perf_iterate_sb_cpu().
2337 smp_store_release(&event
->ctx
, ctx
);
2340 cpu_function_call(cpu
, __perf_install_in_context
, event
);
2345 * Should not happen, we validate the ctx is still alive before calling.
2347 if (WARN_ON_ONCE(task
== TASK_TOMBSTONE
))
2351 * Installing events is tricky because we cannot rely on ctx->is_active
2352 * to be set in case this is the nr_events 0 -> 1 transition.
2354 * Instead we use task_curr(), which tells us if the task is running.
2355 * However, since we use task_curr() outside of rq::lock, we can race
2356 * against the actual state. This means the result can be wrong.
2358 * If we get a false positive, we retry, this is harmless.
2360 * If we get a false negative, things are complicated. If we are after
2361 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2362 * value must be correct. If we're before, it doesn't matter since
2363 * perf_event_context_sched_in() will program the counter.
2365 * However, this hinges on the remote context switch having observed
2366 * our task->perf_event_ctxp[] store, such that it will in fact take
2367 * ctx::lock in perf_event_context_sched_in().
2369 * We do this by task_function_call(), if the IPI fails to hit the task
2370 * we know any future context switch of task must see the
2371 * perf_event_ctpx[] store.
2375 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2376 * task_cpu() load, such that if the IPI then does not find the task
2377 * running, a future context switch of that task must observe the
2382 if (!task_function_call(task
, __perf_install_in_context
, event
))
2385 raw_spin_lock_irq(&ctx
->lock
);
2387 if (WARN_ON_ONCE(task
== TASK_TOMBSTONE
)) {
2389 * Cannot happen because we already checked above (which also
2390 * cannot happen), and we hold ctx->mutex, which serializes us
2391 * against perf_event_exit_task_context().
2393 raw_spin_unlock_irq(&ctx
->lock
);
2397 * If the task is not running, ctx->lock will avoid it becoming so,
2398 * thus we can safely install the event.
2400 if (task_curr(task
)) {
2401 raw_spin_unlock_irq(&ctx
->lock
);
2404 add_event_to_ctx(event
, ctx
);
2405 raw_spin_unlock_irq(&ctx
->lock
);
2409 * Put a event into inactive state and update time fields.
2410 * Enabling the leader of a group effectively enables all
2411 * the group members that aren't explicitly disabled, so we
2412 * have to update their ->tstamp_enabled also.
2413 * Note: this works for group members as well as group leaders
2414 * since the non-leader members' sibling_lists will be empty.
2416 static void __perf_event_mark_enabled(struct perf_event
*event
)
2418 struct perf_event
*sub
;
2419 u64 tstamp
= perf_event_time(event
);
2421 event
->state
= PERF_EVENT_STATE_INACTIVE
;
2422 event
->tstamp_enabled
= tstamp
- event
->total_time_enabled
;
2423 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
2424 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
)
2425 sub
->tstamp_enabled
= tstamp
- sub
->total_time_enabled
;
2430 * Cross CPU call to enable a performance event
2432 static void __perf_event_enable(struct perf_event
*event
,
2433 struct perf_cpu_context
*cpuctx
,
2434 struct perf_event_context
*ctx
,
2437 struct perf_event
*leader
= event
->group_leader
;
2438 struct perf_event_context
*task_ctx
;
2440 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
||
2441 event
->state
<= PERF_EVENT_STATE_ERROR
)
2445 ctx_sched_out(ctx
, cpuctx
, EVENT_TIME
);
2447 __perf_event_mark_enabled(event
);
2449 if (!ctx
->is_active
)
2452 if (!event_filter_match(event
)) {
2453 if (is_cgroup_event(event
))
2454 perf_cgroup_defer_enabled(event
);
2455 ctx_sched_in(ctx
, cpuctx
, EVENT_TIME
, current
);
2460 * If the event is in a group and isn't the group leader,
2461 * then don't put it on unless the group is on.
2463 if (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
) {
2464 ctx_sched_in(ctx
, cpuctx
, EVENT_TIME
, current
);
2468 task_ctx
= cpuctx
->task_ctx
;
2470 WARN_ON_ONCE(task_ctx
!= ctx
);
2472 ctx_resched(cpuctx
, task_ctx
);
2478 * If event->ctx is a cloned context, callers must make sure that
2479 * every task struct that event->ctx->task could possibly point to
2480 * remains valid. This condition is satisfied when called through
2481 * perf_event_for_each_child or perf_event_for_each as described
2482 * for perf_event_disable.
2484 static void _perf_event_enable(struct perf_event
*event
)
2486 struct perf_event_context
*ctx
= event
->ctx
;
2488 raw_spin_lock_irq(&ctx
->lock
);
2489 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
||
2490 event
->state
< PERF_EVENT_STATE_ERROR
) {
2491 raw_spin_unlock_irq(&ctx
->lock
);
2496 * If the event is in error state, clear that first.
2498 * That way, if we see the event in error state below, we know that it
2499 * has gone back into error state, as distinct from the task having
2500 * been scheduled away before the cross-call arrived.
2502 if (event
->state
== PERF_EVENT_STATE_ERROR
)
2503 event
->state
= PERF_EVENT_STATE_OFF
;
2504 raw_spin_unlock_irq(&ctx
->lock
);
2506 event_function_call(event
, __perf_event_enable
, NULL
);
2510 * See perf_event_disable();
2512 void perf_event_enable(struct perf_event
*event
)
2514 struct perf_event_context
*ctx
;
2516 ctx
= perf_event_ctx_lock(event
);
2517 _perf_event_enable(event
);
2518 perf_event_ctx_unlock(event
, ctx
);
2520 EXPORT_SYMBOL_GPL(perf_event_enable
);
2522 struct stop_event_data
{
2523 struct perf_event
*event
;
2524 unsigned int restart
;
2527 static int __perf_event_stop(void *info
)
2529 struct stop_event_data
*sd
= info
;
2530 struct perf_event
*event
= sd
->event
;
2532 /* if it's already INACTIVE, do nothing */
2533 if (READ_ONCE(event
->state
) != PERF_EVENT_STATE_ACTIVE
)
2536 /* matches smp_wmb() in event_sched_in() */
2540 * There is a window with interrupts enabled before we get here,
2541 * so we need to check again lest we try to stop another CPU's event.
2543 if (READ_ONCE(event
->oncpu
) != smp_processor_id())
2546 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
2549 * May race with the actual stop (through perf_pmu_output_stop()),
2550 * but it is only used for events with AUX ring buffer, and such
2551 * events will refuse to restart because of rb::aux_mmap_count==0,
2552 * see comments in perf_aux_output_begin().
2554 * Since this is happening on a event-local CPU, no trace is lost
2558 event
->pmu
->start(event
, 0);
2563 static int perf_event_stop(struct perf_event
*event
, int restart
)
2565 struct stop_event_data sd
= {
2572 if (READ_ONCE(event
->state
) != PERF_EVENT_STATE_ACTIVE
)
2575 /* matches smp_wmb() in event_sched_in() */
2579 * We only want to restart ACTIVE events, so if the event goes
2580 * inactive here (event->oncpu==-1), there's nothing more to do;
2581 * fall through with ret==-ENXIO.
2583 ret
= cpu_function_call(READ_ONCE(event
->oncpu
),
2584 __perf_event_stop
, &sd
);
2585 } while (ret
== -EAGAIN
);
2591 * In order to contain the amount of racy and tricky in the address filter
2592 * configuration management, it is a two part process:
2594 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2595 * we update the addresses of corresponding vmas in
2596 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2597 * (p2) when an event is scheduled in (pmu::add), it calls
2598 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2599 * if the generation has changed since the previous call.
2601 * If (p1) happens while the event is active, we restart it to force (p2).
2603 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2604 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2606 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2607 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2609 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2612 void perf_event_addr_filters_sync(struct perf_event
*event
)
2614 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
2616 if (!has_addr_filter(event
))
2619 raw_spin_lock(&ifh
->lock
);
2620 if (event
->addr_filters_gen
!= event
->hw
.addr_filters_gen
) {
2621 event
->pmu
->addr_filters_sync(event
);
2622 event
->hw
.addr_filters_gen
= event
->addr_filters_gen
;
2624 raw_spin_unlock(&ifh
->lock
);
2626 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync
);
2628 static int _perf_event_refresh(struct perf_event
*event
, int refresh
)
2631 * not supported on inherited events
2633 if (event
->attr
.inherit
|| !is_sampling_event(event
))
2636 atomic_add(refresh
, &event
->event_limit
);
2637 _perf_event_enable(event
);
2643 * See perf_event_disable()
2645 int perf_event_refresh(struct perf_event
*event
, int refresh
)
2647 struct perf_event_context
*ctx
;
2650 ctx
= perf_event_ctx_lock(event
);
2651 ret
= _perf_event_refresh(event
, refresh
);
2652 perf_event_ctx_unlock(event
, ctx
);
2656 EXPORT_SYMBOL_GPL(perf_event_refresh
);
2658 static void ctx_sched_out(struct perf_event_context
*ctx
,
2659 struct perf_cpu_context
*cpuctx
,
2660 enum event_type_t event_type
)
2662 int is_active
= ctx
->is_active
;
2663 struct perf_event
*event
;
2665 lockdep_assert_held(&ctx
->lock
);
2667 if (likely(!ctx
->nr_events
)) {
2669 * See __perf_remove_from_context().
2671 WARN_ON_ONCE(ctx
->is_active
);
2673 WARN_ON_ONCE(cpuctx
->task_ctx
);
2677 ctx
->is_active
&= ~event_type
;
2678 if (!(ctx
->is_active
& EVENT_ALL
))
2682 WARN_ON_ONCE(cpuctx
->task_ctx
!= ctx
);
2683 if (!ctx
->is_active
)
2684 cpuctx
->task_ctx
= NULL
;
2688 * Always update time if it was set; not only when it changes.
2689 * Otherwise we can 'forget' to update time for any but the last
2690 * context we sched out. For example:
2692 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2693 * ctx_sched_out(.event_type = EVENT_PINNED)
2695 * would only update time for the pinned events.
2697 if (is_active
& EVENT_TIME
) {
2698 /* update (and stop) ctx time */
2699 update_context_time(ctx
);
2700 update_cgrp_time_from_cpuctx(cpuctx
);
2703 is_active
^= ctx
->is_active
; /* changed bits */
2705 if (!ctx
->nr_active
|| !(is_active
& EVENT_ALL
))
2708 perf_pmu_disable(ctx
->pmu
);
2709 if (is_active
& EVENT_PINNED
) {
2710 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
)
2711 group_sched_out(event
, cpuctx
, ctx
);
2714 if (is_active
& EVENT_FLEXIBLE
) {
2715 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
)
2716 group_sched_out(event
, cpuctx
, ctx
);
2718 perf_pmu_enable(ctx
->pmu
);
2722 * Test whether two contexts are equivalent, i.e. whether they have both been
2723 * cloned from the same version of the same context.
2725 * Equivalence is measured using a generation number in the context that is
2726 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2727 * and list_del_event().
2729 static int context_equiv(struct perf_event_context
*ctx1
,
2730 struct perf_event_context
*ctx2
)
2732 lockdep_assert_held(&ctx1
->lock
);
2733 lockdep_assert_held(&ctx2
->lock
);
2735 /* Pinning disables the swap optimization */
2736 if (ctx1
->pin_count
|| ctx2
->pin_count
)
2739 /* If ctx1 is the parent of ctx2 */
2740 if (ctx1
== ctx2
->parent_ctx
&& ctx1
->generation
== ctx2
->parent_gen
)
2743 /* If ctx2 is the parent of ctx1 */
2744 if (ctx1
->parent_ctx
== ctx2
&& ctx1
->parent_gen
== ctx2
->generation
)
2748 * If ctx1 and ctx2 have the same parent; we flatten the parent
2749 * hierarchy, see perf_event_init_context().
2751 if (ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
&&
2752 ctx1
->parent_gen
== ctx2
->parent_gen
)
2759 static void __perf_event_sync_stat(struct perf_event
*event
,
2760 struct perf_event
*next_event
)
2764 if (!event
->attr
.inherit_stat
)
2768 * Update the event value, we cannot use perf_event_read()
2769 * because we're in the middle of a context switch and have IRQs
2770 * disabled, which upsets smp_call_function_single(), however
2771 * we know the event must be on the current CPU, therefore we
2772 * don't need to use it.
2774 switch (event
->state
) {
2775 case PERF_EVENT_STATE_ACTIVE
:
2776 event
->pmu
->read(event
);
2779 case PERF_EVENT_STATE_INACTIVE
:
2780 update_event_times(event
);
2788 * In order to keep per-task stats reliable we need to flip the event
2789 * values when we flip the contexts.
2791 value
= local64_read(&next_event
->count
);
2792 value
= local64_xchg(&event
->count
, value
);
2793 local64_set(&next_event
->count
, value
);
2795 swap(event
->total_time_enabled
, next_event
->total_time_enabled
);
2796 swap(event
->total_time_running
, next_event
->total_time_running
);
2799 * Since we swizzled the values, update the user visible data too.
2801 perf_event_update_userpage(event
);
2802 perf_event_update_userpage(next_event
);
2805 static void perf_event_sync_stat(struct perf_event_context
*ctx
,
2806 struct perf_event_context
*next_ctx
)
2808 struct perf_event
*event
, *next_event
;
2813 update_context_time(ctx
);
2815 event
= list_first_entry(&ctx
->event_list
,
2816 struct perf_event
, event_entry
);
2818 next_event
= list_first_entry(&next_ctx
->event_list
,
2819 struct perf_event
, event_entry
);
2821 while (&event
->event_entry
!= &ctx
->event_list
&&
2822 &next_event
->event_entry
!= &next_ctx
->event_list
) {
2824 __perf_event_sync_stat(event
, next_event
);
2826 event
= list_next_entry(event
, event_entry
);
2827 next_event
= list_next_entry(next_event
, event_entry
);
2831 static void perf_event_context_sched_out(struct task_struct
*task
, int ctxn
,
2832 struct task_struct
*next
)
2834 struct perf_event_context
*ctx
= task
->perf_event_ctxp
[ctxn
];
2835 struct perf_event_context
*next_ctx
;
2836 struct perf_event_context
*parent
, *next_parent
;
2837 struct perf_cpu_context
*cpuctx
;
2843 cpuctx
= __get_cpu_context(ctx
);
2844 if (!cpuctx
->task_ctx
)
2848 next_ctx
= next
->perf_event_ctxp
[ctxn
];
2852 parent
= rcu_dereference(ctx
->parent_ctx
);
2853 next_parent
= rcu_dereference(next_ctx
->parent_ctx
);
2855 /* If neither context have a parent context; they cannot be clones. */
2856 if (!parent
&& !next_parent
)
2859 if (next_parent
== ctx
|| next_ctx
== parent
|| next_parent
== parent
) {
2861 * Looks like the two contexts are clones, so we might be
2862 * able to optimize the context switch. We lock both
2863 * contexts and check that they are clones under the
2864 * lock (including re-checking that neither has been
2865 * uncloned in the meantime). It doesn't matter which
2866 * order we take the locks because no other cpu could
2867 * be trying to lock both of these tasks.
2869 raw_spin_lock(&ctx
->lock
);
2870 raw_spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
2871 if (context_equiv(ctx
, next_ctx
)) {
2872 WRITE_ONCE(ctx
->task
, next
);
2873 WRITE_ONCE(next_ctx
->task
, task
);
2875 swap(ctx
->task_ctx_data
, next_ctx
->task_ctx_data
);
2878 * RCU_INIT_POINTER here is safe because we've not
2879 * modified the ctx and the above modification of
2880 * ctx->task and ctx->task_ctx_data are immaterial
2881 * since those values are always verified under
2882 * ctx->lock which we're now holding.
2884 RCU_INIT_POINTER(task
->perf_event_ctxp
[ctxn
], next_ctx
);
2885 RCU_INIT_POINTER(next
->perf_event_ctxp
[ctxn
], ctx
);
2889 perf_event_sync_stat(ctx
, next_ctx
);
2891 raw_spin_unlock(&next_ctx
->lock
);
2892 raw_spin_unlock(&ctx
->lock
);
2898 raw_spin_lock(&ctx
->lock
);
2899 task_ctx_sched_out(cpuctx
, ctx
);
2900 raw_spin_unlock(&ctx
->lock
);
2904 static DEFINE_PER_CPU(struct list_head
, sched_cb_list
);
2906 void perf_sched_cb_dec(struct pmu
*pmu
)
2908 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
2910 this_cpu_dec(perf_sched_cb_usages
);
2912 if (!--cpuctx
->sched_cb_usage
)
2913 list_del(&cpuctx
->sched_cb_entry
);
2917 void perf_sched_cb_inc(struct pmu
*pmu
)
2919 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
2921 if (!cpuctx
->sched_cb_usage
++)
2922 list_add(&cpuctx
->sched_cb_entry
, this_cpu_ptr(&sched_cb_list
));
2924 this_cpu_inc(perf_sched_cb_usages
);
2928 * This function provides the context switch callback to the lower code
2929 * layer. It is invoked ONLY when the context switch callback is enabled.
2931 * This callback is relevant even to per-cpu events; for example multi event
2932 * PEBS requires this to provide PID/TID information. This requires we flush
2933 * all queued PEBS records before we context switch to a new task.
2935 static void perf_pmu_sched_task(struct task_struct
*prev
,
2936 struct task_struct
*next
,
2939 struct perf_cpu_context
*cpuctx
;
2945 list_for_each_entry(cpuctx
, this_cpu_ptr(&sched_cb_list
), sched_cb_entry
) {
2946 pmu
= cpuctx
->unique_pmu
; /* software PMUs will not have sched_task */
2948 if (WARN_ON_ONCE(!pmu
->sched_task
))
2951 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
2952 perf_pmu_disable(pmu
);
2954 pmu
->sched_task(cpuctx
->task_ctx
, sched_in
);
2956 perf_pmu_enable(pmu
);
2957 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
2961 static void perf_event_switch(struct task_struct
*task
,
2962 struct task_struct
*next_prev
, bool sched_in
);
2964 #define for_each_task_context_nr(ctxn) \
2965 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2968 * Called from scheduler to remove the events of the current task,
2969 * with interrupts disabled.
2971 * We stop each event and update the event value in event->count.
2973 * This does not protect us against NMI, but disable()
2974 * sets the disabled bit in the control field of event _before_
2975 * accessing the event control register. If a NMI hits, then it will
2976 * not restart the event.
2978 void __perf_event_task_sched_out(struct task_struct
*task
,
2979 struct task_struct
*next
)
2983 if (__this_cpu_read(perf_sched_cb_usages
))
2984 perf_pmu_sched_task(task
, next
, false);
2986 if (atomic_read(&nr_switch_events
))
2987 perf_event_switch(task
, next
, false);
2989 for_each_task_context_nr(ctxn
)
2990 perf_event_context_sched_out(task
, ctxn
, next
);
2993 * if cgroup events exist on this CPU, then we need
2994 * to check if we have to switch out PMU state.
2995 * cgroup event are system-wide mode only
2997 if (atomic_read(this_cpu_ptr(&perf_cgroup_events
)))
2998 perf_cgroup_sched_out(task
, next
);
3002 * Called with IRQs disabled
3004 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
3005 enum event_type_t event_type
)
3007 ctx_sched_out(&cpuctx
->ctx
, cpuctx
, event_type
);
3011 ctx_pinned_sched_in(struct perf_event_context
*ctx
,
3012 struct perf_cpu_context
*cpuctx
)
3014 struct perf_event
*event
;
3016 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
3017 if (event
->state
<= PERF_EVENT_STATE_OFF
)
3019 if (!event_filter_match(event
))
3022 /* may need to reset tstamp_enabled */
3023 if (is_cgroup_event(event
))
3024 perf_cgroup_mark_enabled(event
, ctx
);
3026 if (group_can_go_on(event
, cpuctx
, 1))
3027 group_sched_in(event
, cpuctx
, ctx
);
3030 * If this pinned group hasn't been scheduled,
3031 * put it in error state.
3033 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
3034 update_group_times(event
);
3035 event
->state
= PERF_EVENT_STATE_ERROR
;
3041 ctx_flexible_sched_in(struct perf_event_context
*ctx
,
3042 struct perf_cpu_context
*cpuctx
)
3044 struct perf_event
*event
;
3047 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
3048 /* Ignore events in OFF or ERROR state */
3049 if (event
->state
<= PERF_EVENT_STATE_OFF
)
3052 * Listen to the 'cpu' scheduling filter constraint
3055 if (!event_filter_match(event
))
3058 /* may need to reset tstamp_enabled */
3059 if (is_cgroup_event(event
))
3060 perf_cgroup_mark_enabled(event
, ctx
);
3062 if (group_can_go_on(event
, cpuctx
, can_add_hw
)) {
3063 if (group_sched_in(event
, cpuctx
, ctx
))
3070 ctx_sched_in(struct perf_event_context
*ctx
,
3071 struct perf_cpu_context
*cpuctx
,
3072 enum event_type_t event_type
,
3073 struct task_struct
*task
)
3075 int is_active
= ctx
->is_active
;
3078 lockdep_assert_held(&ctx
->lock
);
3080 if (likely(!ctx
->nr_events
))
3083 ctx
->is_active
|= (event_type
| EVENT_TIME
);
3086 cpuctx
->task_ctx
= ctx
;
3088 WARN_ON_ONCE(cpuctx
->task_ctx
!= ctx
);
3091 is_active
^= ctx
->is_active
; /* changed bits */
3093 if (is_active
& EVENT_TIME
) {
3094 /* start ctx time */
3096 ctx
->timestamp
= now
;
3097 perf_cgroup_set_timestamp(task
, ctx
);
3101 * First go through the list and put on any pinned groups
3102 * in order to give them the best chance of going on.
3104 if (is_active
& EVENT_PINNED
)
3105 ctx_pinned_sched_in(ctx
, cpuctx
);
3107 /* Then walk through the lower prio flexible groups */
3108 if (is_active
& EVENT_FLEXIBLE
)
3109 ctx_flexible_sched_in(ctx
, cpuctx
);
3112 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
3113 enum event_type_t event_type
,
3114 struct task_struct
*task
)
3116 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
3118 ctx_sched_in(ctx
, cpuctx
, event_type
, task
);
3121 static void perf_event_context_sched_in(struct perf_event_context
*ctx
,
3122 struct task_struct
*task
)
3124 struct perf_cpu_context
*cpuctx
;
3126 cpuctx
= __get_cpu_context(ctx
);
3127 if (cpuctx
->task_ctx
== ctx
)
3130 perf_ctx_lock(cpuctx
, ctx
);
3131 perf_pmu_disable(ctx
->pmu
);
3133 * We want to keep the following priority order:
3134 * cpu pinned (that don't need to move), task pinned,
3135 * cpu flexible, task flexible.
3137 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
3138 perf_event_sched_in(cpuctx
, ctx
, task
);
3139 perf_pmu_enable(ctx
->pmu
);
3140 perf_ctx_unlock(cpuctx
, ctx
);
3144 * Called from scheduler to add the events of the current task
3145 * with interrupts disabled.
3147 * We restore the event value and then enable it.
3149 * This does not protect us against NMI, but enable()
3150 * sets the enabled bit in the control field of event _before_
3151 * accessing the event control register. If a NMI hits, then it will
3152 * keep the event running.
3154 void __perf_event_task_sched_in(struct task_struct
*prev
,
3155 struct task_struct
*task
)
3157 struct perf_event_context
*ctx
;
3161 * If cgroup events exist on this CPU, then we need to check if we have
3162 * to switch in PMU state; cgroup event are system-wide mode only.
3164 * Since cgroup events are CPU events, we must schedule these in before
3165 * we schedule in the task events.
3167 if (atomic_read(this_cpu_ptr(&perf_cgroup_events
)))
3168 perf_cgroup_sched_in(prev
, task
);
3170 for_each_task_context_nr(ctxn
) {
3171 ctx
= task
->perf_event_ctxp
[ctxn
];
3175 perf_event_context_sched_in(ctx
, task
);
3178 if (atomic_read(&nr_switch_events
))
3179 perf_event_switch(task
, prev
, true);
3181 if (__this_cpu_read(perf_sched_cb_usages
))
3182 perf_pmu_sched_task(prev
, task
, true);
3185 static u64
perf_calculate_period(struct perf_event
*event
, u64 nsec
, u64 count
)
3187 u64 frequency
= event
->attr
.sample_freq
;
3188 u64 sec
= NSEC_PER_SEC
;
3189 u64 divisor
, dividend
;
3191 int count_fls
, nsec_fls
, frequency_fls
, sec_fls
;
3193 count_fls
= fls64(count
);
3194 nsec_fls
= fls64(nsec
);
3195 frequency_fls
= fls64(frequency
);
3199 * We got @count in @nsec, with a target of sample_freq HZ
3200 * the target period becomes:
3203 * period = -------------------
3204 * @nsec * sample_freq
3209 * Reduce accuracy by one bit such that @a and @b converge
3210 * to a similar magnitude.
3212 #define REDUCE_FLS(a, b) \
3214 if (a##_fls > b##_fls) { \
3224 * Reduce accuracy until either term fits in a u64, then proceed with
3225 * the other, so that finally we can do a u64/u64 division.
3227 while (count_fls
+ sec_fls
> 64 && nsec_fls
+ frequency_fls
> 64) {
3228 REDUCE_FLS(nsec
, frequency
);
3229 REDUCE_FLS(sec
, count
);
3232 if (count_fls
+ sec_fls
> 64) {
3233 divisor
= nsec
* frequency
;
3235 while (count_fls
+ sec_fls
> 64) {
3236 REDUCE_FLS(count
, sec
);
3240 dividend
= count
* sec
;
3242 dividend
= count
* sec
;
3244 while (nsec_fls
+ frequency_fls
> 64) {
3245 REDUCE_FLS(nsec
, frequency
);
3249 divisor
= nsec
* frequency
;
3255 return div64_u64(dividend
, divisor
);
3258 static DEFINE_PER_CPU(int, perf_throttled_count
);
3259 static DEFINE_PER_CPU(u64
, perf_throttled_seq
);
3261 static void perf_adjust_period(struct perf_event
*event
, u64 nsec
, u64 count
, bool disable
)
3263 struct hw_perf_event
*hwc
= &event
->hw
;
3264 s64 period
, sample_period
;
3267 period
= perf_calculate_period(event
, nsec
, count
);
3269 delta
= (s64
)(period
- hwc
->sample_period
);
3270 delta
= (delta
+ 7) / 8; /* low pass filter */
3272 sample_period
= hwc
->sample_period
+ delta
;
3277 hwc
->sample_period
= sample_period
;
3279 if (local64_read(&hwc
->period_left
) > 8*sample_period
) {
3281 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
3283 local64_set(&hwc
->period_left
, 0);
3286 event
->pmu
->start(event
, PERF_EF_RELOAD
);
3291 * combine freq adjustment with unthrottling to avoid two passes over the
3292 * events. At the same time, make sure, having freq events does not change
3293 * the rate of unthrottling as that would introduce bias.
3295 static void perf_adjust_freq_unthr_context(struct perf_event_context
*ctx
,
3298 struct perf_event
*event
;
3299 struct hw_perf_event
*hwc
;
3300 u64 now
, period
= TICK_NSEC
;
3304 * only need to iterate over all events iff:
3305 * - context have events in frequency mode (needs freq adjust)
3306 * - there are events to unthrottle on this cpu
3308 if (!(ctx
->nr_freq
|| needs_unthr
))
3311 raw_spin_lock(&ctx
->lock
);
3312 perf_pmu_disable(ctx
->pmu
);
3314 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3315 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
3318 if (!event_filter_match(event
))
3321 perf_pmu_disable(event
->pmu
);
3325 if (hwc
->interrupts
== MAX_INTERRUPTS
) {
3326 hwc
->interrupts
= 0;
3327 perf_log_throttle(event
, 1);
3328 event
->pmu
->start(event
, 0);
3331 if (!event
->attr
.freq
|| !event
->attr
.sample_freq
)
3335 * stop the event and update event->count
3337 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
3339 now
= local64_read(&event
->count
);
3340 delta
= now
- hwc
->freq_count_stamp
;
3341 hwc
->freq_count_stamp
= now
;
3345 * reload only if value has changed
3346 * we have stopped the event so tell that
3347 * to perf_adjust_period() to avoid stopping it
3351 perf_adjust_period(event
, period
, delta
, false);
3353 event
->pmu
->start(event
, delta
> 0 ? PERF_EF_RELOAD
: 0);
3355 perf_pmu_enable(event
->pmu
);
3358 perf_pmu_enable(ctx
->pmu
);
3359 raw_spin_unlock(&ctx
->lock
);
3363 * Round-robin a context's events:
3365 static void rotate_ctx(struct perf_event_context
*ctx
)
3368 * Rotate the first entry last of non-pinned groups. Rotation might be
3369 * disabled by the inheritance code.
3371 if (!ctx
->rotate_disable
)
3372 list_rotate_left(&ctx
->flexible_groups
);
3375 static int perf_rotate_context(struct perf_cpu_context
*cpuctx
)
3377 struct perf_event_context
*ctx
= NULL
;
3380 if (cpuctx
->ctx
.nr_events
) {
3381 if (cpuctx
->ctx
.nr_events
!= cpuctx
->ctx
.nr_active
)
3385 ctx
= cpuctx
->task_ctx
;
3386 if (ctx
&& ctx
->nr_events
) {
3387 if (ctx
->nr_events
!= ctx
->nr_active
)
3394 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
3395 perf_pmu_disable(cpuctx
->ctx
.pmu
);
3397 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
3399 ctx_sched_out(ctx
, cpuctx
, EVENT_FLEXIBLE
);
3401 rotate_ctx(&cpuctx
->ctx
);
3405 perf_event_sched_in(cpuctx
, ctx
, current
);
3407 perf_pmu_enable(cpuctx
->ctx
.pmu
);
3408 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
3414 void perf_event_task_tick(void)
3416 struct list_head
*head
= this_cpu_ptr(&active_ctx_list
);
3417 struct perf_event_context
*ctx
, *tmp
;
3420 WARN_ON(!irqs_disabled());
3422 __this_cpu_inc(perf_throttled_seq
);
3423 throttled
= __this_cpu_xchg(perf_throttled_count
, 0);
3424 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS
);
3426 list_for_each_entry_safe(ctx
, tmp
, head
, active_ctx_list
)
3427 perf_adjust_freq_unthr_context(ctx
, throttled
);
3430 static int event_enable_on_exec(struct perf_event
*event
,
3431 struct perf_event_context
*ctx
)
3433 if (!event
->attr
.enable_on_exec
)
3436 event
->attr
.enable_on_exec
= 0;
3437 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
3440 __perf_event_mark_enabled(event
);
3446 * Enable all of a task's events that have been marked enable-on-exec.
3447 * This expects task == current.
3449 static void perf_event_enable_on_exec(int ctxn
)
3451 struct perf_event_context
*ctx
, *clone_ctx
= NULL
;
3452 struct perf_cpu_context
*cpuctx
;
3453 struct perf_event
*event
;
3454 unsigned long flags
;
3457 local_irq_save(flags
);
3458 ctx
= current
->perf_event_ctxp
[ctxn
];
3459 if (!ctx
|| !ctx
->nr_events
)
3462 cpuctx
= __get_cpu_context(ctx
);
3463 perf_ctx_lock(cpuctx
, ctx
);
3464 ctx_sched_out(ctx
, cpuctx
, EVENT_TIME
);
3465 list_for_each_entry(event
, &ctx
->event_list
, event_entry
)
3466 enabled
|= event_enable_on_exec(event
, ctx
);
3469 * Unclone and reschedule this context if we enabled any event.
3472 clone_ctx
= unclone_ctx(ctx
);
3473 ctx_resched(cpuctx
, ctx
);
3475 perf_ctx_unlock(cpuctx
, ctx
);
3478 local_irq_restore(flags
);
3484 struct perf_read_data
{
3485 struct perf_event
*event
;
3490 static int find_cpu_to_read(struct perf_event
*event
, int local_cpu
)
3492 int event_cpu
= event
->oncpu
;
3493 u16 local_pkg
, event_pkg
;
3495 if (event
->group_caps
& PERF_EV_CAP_READ_ACTIVE_PKG
) {
3496 event_pkg
= topology_physical_package_id(event_cpu
);
3497 local_pkg
= topology_physical_package_id(local_cpu
);
3499 if (event_pkg
== local_pkg
)
3507 * Cross CPU call to read the hardware event
3509 static void __perf_event_read(void *info
)
3511 struct perf_read_data
*data
= info
;
3512 struct perf_event
*sub
, *event
= data
->event
;
3513 struct perf_event_context
*ctx
= event
->ctx
;
3514 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
3515 struct pmu
*pmu
= event
->pmu
;
3518 * If this is a task context, we need to check whether it is
3519 * the current task context of this cpu. If not it has been
3520 * scheduled out before the smp call arrived. In that case
3521 * event->count would have been updated to a recent sample
3522 * when the event was scheduled out.
3524 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
3527 raw_spin_lock(&ctx
->lock
);
3528 if (ctx
->is_active
) {
3529 update_context_time(ctx
);
3530 update_cgrp_time_from_event(event
);
3533 update_event_times(event
);
3534 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
3543 pmu
->start_txn(pmu
, PERF_PMU_TXN_READ
);
3547 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
3548 update_event_times(sub
);
3549 if (sub
->state
== PERF_EVENT_STATE_ACTIVE
) {
3551 * Use sibling's PMU rather than @event's since
3552 * sibling could be on different (eg: software) PMU.
3554 sub
->pmu
->read(sub
);
3558 data
->ret
= pmu
->commit_txn(pmu
);
3561 raw_spin_unlock(&ctx
->lock
);
3564 static inline u64
perf_event_count(struct perf_event
*event
)
3566 if (event
->pmu
->count
)
3567 return event
->pmu
->count(event
);
3569 return __perf_event_count(event
);
3573 * NMI-safe method to read a local event, that is an event that
3575 * - either for the current task, or for this CPU
3576 * - does not have inherit set, for inherited task events
3577 * will not be local and we cannot read them atomically
3578 * - must not have a pmu::count method
3580 u64
perf_event_read_local(struct perf_event
*event
)
3582 unsigned long flags
;
3586 * Disabling interrupts avoids all counter scheduling (context
3587 * switches, timer based rotation and IPIs).
3589 local_irq_save(flags
);
3591 /* If this is a per-task event, it must be for current */
3592 WARN_ON_ONCE((event
->attach_state
& PERF_ATTACH_TASK
) &&
3593 event
->hw
.target
!= current
);
3595 /* If this is a per-CPU event, it must be for this CPU */
3596 WARN_ON_ONCE(!(event
->attach_state
& PERF_ATTACH_TASK
) &&
3597 event
->cpu
!= smp_processor_id());
3600 * It must not be an event with inherit set, we cannot read
3601 * all child counters from atomic context.
3603 WARN_ON_ONCE(event
->attr
.inherit
);
3606 * It must not have a pmu::count method, those are not
3609 WARN_ON_ONCE(event
->pmu
->count
);
3612 * If the event is currently on this CPU, its either a per-task event,
3613 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3616 if (event
->oncpu
== smp_processor_id())
3617 event
->pmu
->read(event
);
3619 val
= local64_read(&event
->count
);
3620 local_irq_restore(flags
);
3625 static int perf_event_read(struct perf_event
*event
, bool group
)
3627 int ret
= 0, cpu_to_read
, local_cpu
;
3630 * If event is enabled and currently active on a CPU, update the
3631 * value in the event structure:
3633 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
3634 struct perf_read_data data
= {
3640 local_cpu
= get_cpu();
3641 cpu_to_read
= find_cpu_to_read(event
, local_cpu
);
3645 * Purposely ignore the smp_call_function_single() return
3648 * If event->oncpu isn't a valid CPU it means the event got
3649 * scheduled out and that will have updated the event count.
3651 * Therefore, either way, we'll have an up-to-date event count
3654 (void)smp_call_function_single(cpu_to_read
, __perf_event_read
, &data
, 1);
3656 } else if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
3657 struct perf_event_context
*ctx
= event
->ctx
;
3658 unsigned long flags
;
3660 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
3662 * may read while context is not active
3663 * (e.g., thread is blocked), in that case
3664 * we cannot update context time
3666 if (ctx
->is_active
) {
3667 update_context_time(ctx
);
3668 update_cgrp_time_from_event(event
);
3671 update_group_times(event
);
3673 update_event_times(event
);
3674 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
3681 * Initialize the perf_event context in a task_struct:
3683 static void __perf_event_init_context(struct perf_event_context
*ctx
)
3685 raw_spin_lock_init(&ctx
->lock
);
3686 mutex_init(&ctx
->mutex
);
3687 INIT_LIST_HEAD(&ctx
->active_ctx_list
);
3688 INIT_LIST_HEAD(&ctx
->pinned_groups
);
3689 INIT_LIST_HEAD(&ctx
->flexible_groups
);
3690 INIT_LIST_HEAD(&ctx
->event_list
);
3691 atomic_set(&ctx
->refcount
, 1);
3694 static struct perf_event_context
*
3695 alloc_perf_context(struct pmu
*pmu
, struct task_struct
*task
)
3697 struct perf_event_context
*ctx
;
3699 ctx
= kzalloc(sizeof(struct perf_event_context
), GFP_KERNEL
);
3703 __perf_event_init_context(ctx
);
3706 get_task_struct(task
);
3713 static struct task_struct
*
3714 find_lively_task_by_vpid(pid_t vpid
)
3716 struct task_struct
*task
;
3722 task
= find_task_by_vpid(vpid
);
3724 get_task_struct(task
);
3728 return ERR_PTR(-ESRCH
);
3734 * Returns a matching context with refcount and pincount.
3736 static struct perf_event_context
*
3737 find_get_context(struct pmu
*pmu
, struct task_struct
*task
,
3738 struct perf_event
*event
)
3740 struct perf_event_context
*ctx
, *clone_ctx
= NULL
;
3741 struct perf_cpu_context
*cpuctx
;
3742 void *task_ctx_data
= NULL
;
3743 unsigned long flags
;
3745 int cpu
= event
->cpu
;
3748 /* Must be root to operate on a CPU event: */
3749 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN
))
3750 return ERR_PTR(-EACCES
);
3753 * We could be clever and allow to attach a event to an
3754 * offline CPU and activate it when the CPU comes up, but
3757 if (!cpu_online(cpu
))
3758 return ERR_PTR(-ENODEV
);
3760 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
3769 ctxn
= pmu
->task_ctx_nr
;
3773 if (event
->attach_state
& PERF_ATTACH_TASK_DATA
) {
3774 task_ctx_data
= kzalloc(pmu
->task_ctx_size
, GFP_KERNEL
);
3775 if (!task_ctx_data
) {
3782 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
3784 clone_ctx
= unclone_ctx(ctx
);
3787 if (task_ctx_data
&& !ctx
->task_ctx_data
) {
3788 ctx
->task_ctx_data
= task_ctx_data
;
3789 task_ctx_data
= NULL
;
3791 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
3796 ctx
= alloc_perf_context(pmu
, task
);
3801 if (task_ctx_data
) {
3802 ctx
->task_ctx_data
= task_ctx_data
;
3803 task_ctx_data
= NULL
;
3807 mutex_lock(&task
->perf_event_mutex
);
3809 * If it has already passed perf_event_exit_task().
3810 * we must see PF_EXITING, it takes this mutex too.
3812 if (task
->flags
& PF_EXITING
)
3814 else if (task
->perf_event_ctxp
[ctxn
])
3819 rcu_assign_pointer(task
->perf_event_ctxp
[ctxn
], ctx
);
3821 mutex_unlock(&task
->perf_event_mutex
);
3823 if (unlikely(err
)) {
3832 kfree(task_ctx_data
);
3836 kfree(task_ctx_data
);
3837 return ERR_PTR(err
);
3840 static void perf_event_free_filter(struct perf_event
*event
);
3841 static void perf_event_free_bpf_prog(struct perf_event
*event
);
3843 static void free_event_rcu(struct rcu_head
*head
)
3845 struct perf_event
*event
;
3847 event
= container_of(head
, struct perf_event
, rcu_head
);
3849 put_pid_ns(event
->ns
);
3850 perf_event_free_filter(event
);
3854 static void ring_buffer_attach(struct perf_event
*event
,
3855 struct ring_buffer
*rb
);
3857 static void detach_sb_event(struct perf_event
*event
)
3859 struct pmu_event_list
*pel
= per_cpu_ptr(&pmu_sb_events
, event
->cpu
);
3861 raw_spin_lock(&pel
->lock
);
3862 list_del_rcu(&event
->sb_list
);
3863 raw_spin_unlock(&pel
->lock
);
3866 static bool is_sb_event(struct perf_event
*event
)
3868 struct perf_event_attr
*attr
= &event
->attr
;
3873 if (event
->attach_state
& PERF_ATTACH_TASK
)
3876 if (attr
->mmap
|| attr
->mmap_data
|| attr
->mmap2
||
3877 attr
->comm
|| attr
->comm_exec
||
3879 attr
->context_switch
)
3884 static void unaccount_pmu_sb_event(struct perf_event
*event
)
3886 if (is_sb_event(event
))
3887 detach_sb_event(event
);
3890 static void unaccount_event_cpu(struct perf_event
*event
, int cpu
)
3895 if (is_cgroup_event(event
))
3896 atomic_dec(&per_cpu(perf_cgroup_events
, cpu
));
3899 #ifdef CONFIG_NO_HZ_FULL
3900 static DEFINE_SPINLOCK(nr_freq_lock
);
3903 static void unaccount_freq_event_nohz(void)
3905 #ifdef CONFIG_NO_HZ_FULL
3906 spin_lock(&nr_freq_lock
);
3907 if (atomic_dec_and_test(&nr_freq_events
))
3908 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS
);
3909 spin_unlock(&nr_freq_lock
);
3913 static void unaccount_freq_event(void)
3915 if (tick_nohz_full_enabled())
3916 unaccount_freq_event_nohz();
3918 atomic_dec(&nr_freq_events
);
3921 static void unaccount_event(struct perf_event
*event
)
3928 if (event
->attach_state
& PERF_ATTACH_TASK
)
3930 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
3931 atomic_dec(&nr_mmap_events
);
3932 if (event
->attr
.comm
)
3933 atomic_dec(&nr_comm_events
);
3934 if (event
->attr
.task
)
3935 atomic_dec(&nr_task_events
);
3936 if (event
->attr
.freq
)
3937 unaccount_freq_event();
3938 if (event
->attr
.context_switch
) {
3940 atomic_dec(&nr_switch_events
);
3942 if (is_cgroup_event(event
))
3944 if (has_branch_stack(event
))
3948 if (!atomic_add_unless(&perf_sched_count
, -1, 1))
3949 schedule_delayed_work(&perf_sched_work
, HZ
);
3952 unaccount_event_cpu(event
, event
->cpu
);
3954 unaccount_pmu_sb_event(event
);
3957 static void perf_sched_delayed(struct work_struct
*work
)
3959 mutex_lock(&perf_sched_mutex
);
3960 if (atomic_dec_and_test(&perf_sched_count
))
3961 static_branch_disable(&perf_sched_events
);
3962 mutex_unlock(&perf_sched_mutex
);
3966 * The following implement mutual exclusion of events on "exclusive" pmus
3967 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3968 * at a time, so we disallow creating events that might conflict, namely:
3970 * 1) cpu-wide events in the presence of per-task events,
3971 * 2) per-task events in the presence of cpu-wide events,
3972 * 3) two matching events on the same context.
3974 * The former two cases are handled in the allocation path (perf_event_alloc(),
3975 * _free_event()), the latter -- before the first perf_install_in_context().
3977 static int exclusive_event_init(struct perf_event
*event
)
3979 struct pmu
*pmu
= event
->pmu
;
3981 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
3985 * Prevent co-existence of per-task and cpu-wide events on the
3986 * same exclusive pmu.
3988 * Negative pmu::exclusive_cnt means there are cpu-wide
3989 * events on this "exclusive" pmu, positive means there are
3992 * Since this is called in perf_event_alloc() path, event::ctx
3993 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3994 * to mean "per-task event", because unlike other attach states it
3995 * never gets cleared.
3997 if (event
->attach_state
& PERF_ATTACH_TASK
) {
3998 if (!atomic_inc_unless_negative(&pmu
->exclusive_cnt
))
4001 if (!atomic_dec_unless_positive(&pmu
->exclusive_cnt
))
4008 static void exclusive_event_destroy(struct perf_event
*event
)
4010 struct pmu
*pmu
= event
->pmu
;
4012 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
4015 /* see comment in exclusive_event_init() */
4016 if (event
->attach_state
& PERF_ATTACH_TASK
)
4017 atomic_dec(&pmu
->exclusive_cnt
);
4019 atomic_inc(&pmu
->exclusive_cnt
);
4022 static bool exclusive_event_match(struct perf_event
*e1
, struct perf_event
*e2
)
4024 if ((e1
->pmu
== e2
->pmu
) &&
4025 (e1
->cpu
== e2
->cpu
||
4032 /* Called under the same ctx::mutex as perf_install_in_context() */
4033 static bool exclusive_event_installable(struct perf_event
*event
,
4034 struct perf_event_context
*ctx
)
4036 struct perf_event
*iter_event
;
4037 struct pmu
*pmu
= event
->pmu
;
4039 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
4042 list_for_each_entry(iter_event
, &ctx
->event_list
, event_entry
) {
4043 if (exclusive_event_match(iter_event
, event
))
4050 static void perf_addr_filters_splice(struct perf_event
*event
,
4051 struct list_head
*head
);
4053 static void _free_event(struct perf_event
*event
)
4055 irq_work_sync(&event
->pending
);
4057 unaccount_event(event
);
4061 * Can happen when we close an event with re-directed output.
4063 * Since we have a 0 refcount, perf_mmap_close() will skip
4064 * over us; possibly making our ring_buffer_put() the last.
4066 mutex_lock(&event
->mmap_mutex
);
4067 ring_buffer_attach(event
, NULL
);
4068 mutex_unlock(&event
->mmap_mutex
);
4071 if (is_cgroup_event(event
))
4072 perf_detach_cgroup(event
);
4074 if (!event
->parent
) {
4075 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
)
4076 put_callchain_buffers();
4079 perf_event_free_bpf_prog(event
);
4080 perf_addr_filters_splice(event
, NULL
);
4081 kfree(event
->addr_filters_offs
);
4084 event
->destroy(event
);
4087 put_ctx(event
->ctx
);
4089 exclusive_event_destroy(event
);
4090 module_put(event
->pmu
->module
);
4092 call_rcu(&event
->rcu_head
, free_event_rcu
);
4096 * Used to free events which have a known refcount of 1, such as in error paths
4097 * where the event isn't exposed yet and inherited events.
4099 static void free_event(struct perf_event
*event
)
4101 if (WARN(atomic_long_cmpxchg(&event
->refcount
, 1, 0) != 1,
4102 "unexpected event refcount: %ld; ptr=%p\n",
4103 atomic_long_read(&event
->refcount
), event
)) {
4104 /* leak to avoid use-after-free */
4112 * Remove user event from the owner task.
4114 static void perf_remove_from_owner(struct perf_event
*event
)
4116 struct task_struct
*owner
;
4120 * Matches the smp_store_release() in perf_event_exit_task(). If we
4121 * observe !owner it means the list deletion is complete and we can
4122 * indeed free this event, otherwise we need to serialize on
4123 * owner->perf_event_mutex.
4125 owner
= lockless_dereference(event
->owner
);
4128 * Since delayed_put_task_struct() also drops the last
4129 * task reference we can safely take a new reference
4130 * while holding the rcu_read_lock().
4132 get_task_struct(owner
);
4138 * If we're here through perf_event_exit_task() we're already
4139 * holding ctx->mutex which would be an inversion wrt. the
4140 * normal lock order.
4142 * However we can safely take this lock because its the child
4145 mutex_lock_nested(&owner
->perf_event_mutex
, SINGLE_DEPTH_NESTING
);
4148 * We have to re-check the event->owner field, if it is cleared
4149 * we raced with perf_event_exit_task(), acquiring the mutex
4150 * ensured they're done, and we can proceed with freeing the
4154 list_del_init(&event
->owner_entry
);
4155 smp_store_release(&event
->owner
, NULL
);
4157 mutex_unlock(&owner
->perf_event_mutex
);
4158 put_task_struct(owner
);
4162 static void put_event(struct perf_event
*event
)
4164 if (!atomic_long_dec_and_test(&event
->refcount
))
4171 * Kill an event dead; while event:refcount will preserve the event
4172 * object, it will not preserve its functionality. Once the last 'user'
4173 * gives up the object, we'll destroy the thing.
4175 int perf_event_release_kernel(struct perf_event
*event
)
4177 struct perf_event_context
*ctx
= event
->ctx
;
4178 struct perf_event
*child
, *tmp
;
4181 * If we got here through err_file: fput(event_file); we will not have
4182 * attached to a context yet.
4185 WARN_ON_ONCE(event
->attach_state
&
4186 (PERF_ATTACH_CONTEXT
|PERF_ATTACH_GROUP
));
4190 if (!is_kernel_event(event
))
4191 perf_remove_from_owner(event
);
4193 ctx
= perf_event_ctx_lock(event
);
4194 WARN_ON_ONCE(ctx
->parent_ctx
);
4195 perf_remove_from_context(event
, DETACH_GROUP
);
4197 raw_spin_lock_irq(&ctx
->lock
);
4199 * Mark this even as STATE_DEAD, there is no external reference to it
4202 * Anybody acquiring event->child_mutex after the below loop _must_
4203 * also see this, most importantly inherit_event() which will avoid
4204 * placing more children on the list.
4206 * Thus this guarantees that we will in fact observe and kill _ALL_
4209 event
->state
= PERF_EVENT_STATE_DEAD
;
4210 raw_spin_unlock_irq(&ctx
->lock
);
4212 perf_event_ctx_unlock(event
, ctx
);
4215 mutex_lock(&event
->child_mutex
);
4216 list_for_each_entry(child
, &event
->child_list
, child_list
) {
4219 * Cannot change, child events are not migrated, see the
4220 * comment with perf_event_ctx_lock_nested().
4222 ctx
= lockless_dereference(child
->ctx
);
4224 * Since child_mutex nests inside ctx::mutex, we must jump
4225 * through hoops. We start by grabbing a reference on the ctx.
4227 * Since the event cannot get freed while we hold the
4228 * child_mutex, the context must also exist and have a !0
4234 * Now that we have a ctx ref, we can drop child_mutex, and
4235 * acquire ctx::mutex without fear of it going away. Then we
4236 * can re-acquire child_mutex.
4238 mutex_unlock(&event
->child_mutex
);
4239 mutex_lock(&ctx
->mutex
);
4240 mutex_lock(&event
->child_mutex
);
4243 * Now that we hold ctx::mutex and child_mutex, revalidate our
4244 * state, if child is still the first entry, it didn't get freed
4245 * and we can continue doing so.
4247 tmp
= list_first_entry_or_null(&event
->child_list
,
4248 struct perf_event
, child_list
);
4250 perf_remove_from_context(child
, DETACH_GROUP
);
4251 list_del(&child
->child_list
);
4254 * This matches the refcount bump in inherit_event();
4255 * this can't be the last reference.
4260 mutex_unlock(&event
->child_mutex
);
4261 mutex_unlock(&ctx
->mutex
);
4265 mutex_unlock(&event
->child_mutex
);
4268 put_event(event
); /* Must be the 'last' reference */
4271 EXPORT_SYMBOL_GPL(perf_event_release_kernel
);
4274 * Called when the last reference to the file is gone.
4276 static int perf_release(struct inode
*inode
, struct file
*file
)
4278 perf_event_release_kernel(file
->private_data
);
4282 u64
perf_event_read_value(struct perf_event
*event
, u64
*enabled
, u64
*running
)
4284 struct perf_event
*child
;
4290 mutex_lock(&event
->child_mutex
);
4292 (void)perf_event_read(event
, false);
4293 total
+= perf_event_count(event
);
4295 *enabled
+= event
->total_time_enabled
+
4296 atomic64_read(&event
->child_total_time_enabled
);
4297 *running
+= event
->total_time_running
+
4298 atomic64_read(&event
->child_total_time_running
);
4300 list_for_each_entry(child
, &event
->child_list
, child_list
) {
4301 (void)perf_event_read(child
, false);
4302 total
+= perf_event_count(child
);
4303 *enabled
+= child
->total_time_enabled
;
4304 *running
+= child
->total_time_running
;
4306 mutex_unlock(&event
->child_mutex
);
4310 EXPORT_SYMBOL_GPL(perf_event_read_value
);
4312 static int __perf_read_group_add(struct perf_event
*leader
,
4313 u64 read_format
, u64
*values
)
4315 struct perf_event
*sub
;
4316 int n
= 1; /* skip @nr */
4319 ret
= perf_event_read(leader
, true);
4324 * Since we co-schedule groups, {enabled,running} times of siblings
4325 * will be identical to those of the leader, so we only publish one
4328 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
4329 values
[n
++] += leader
->total_time_enabled
+
4330 atomic64_read(&leader
->child_total_time_enabled
);
4333 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
4334 values
[n
++] += leader
->total_time_running
+
4335 atomic64_read(&leader
->child_total_time_running
);
4339 * Write {count,id} tuples for every sibling.
4341 values
[n
++] += perf_event_count(leader
);
4342 if (read_format
& PERF_FORMAT_ID
)
4343 values
[n
++] = primary_event_id(leader
);
4345 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
4346 values
[n
++] += perf_event_count(sub
);
4347 if (read_format
& PERF_FORMAT_ID
)
4348 values
[n
++] = primary_event_id(sub
);
4354 static int perf_read_group(struct perf_event
*event
,
4355 u64 read_format
, char __user
*buf
)
4357 struct perf_event
*leader
= event
->group_leader
, *child
;
4358 struct perf_event_context
*ctx
= leader
->ctx
;
4362 lockdep_assert_held(&ctx
->mutex
);
4364 values
= kzalloc(event
->read_size
, GFP_KERNEL
);
4368 values
[0] = 1 + leader
->nr_siblings
;
4371 * By locking the child_mutex of the leader we effectively
4372 * lock the child list of all siblings.. XXX explain how.
4374 mutex_lock(&leader
->child_mutex
);
4376 ret
= __perf_read_group_add(leader
, read_format
, values
);
4380 list_for_each_entry(child
, &leader
->child_list
, child_list
) {
4381 ret
= __perf_read_group_add(child
, read_format
, values
);
4386 mutex_unlock(&leader
->child_mutex
);
4388 ret
= event
->read_size
;
4389 if (copy_to_user(buf
, values
, event
->read_size
))
4394 mutex_unlock(&leader
->child_mutex
);
4400 static int perf_read_one(struct perf_event
*event
,
4401 u64 read_format
, char __user
*buf
)
4403 u64 enabled
, running
;
4407 values
[n
++] = perf_event_read_value(event
, &enabled
, &running
);
4408 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
4409 values
[n
++] = enabled
;
4410 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
4411 values
[n
++] = running
;
4412 if (read_format
& PERF_FORMAT_ID
)
4413 values
[n
++] = primary_event_id(event
);
4415 if (copy_to_user(buf
, values
, n
* sizeof(u64
)))
4418 return n
* sizeof(u64
);
4421 static bool is_event_hup(struct perf_event
*event
)
4425 if (event
->state
> PERF_EVENT_STATE_EXIT
)
4428 mutex_lock(&event
->child_mutex
);
4429 no_children
= list_empty(&event
->child_list
);
4430 mutex_unlock(&event
->child_mutex
);
4435 * Read the performance event - simple non blocking version for now
4438 __perf_read(struct perf_event
*event
, char __user
*buf
, size_t count
)
4440 u64 read_format
= event
->attr
.read_format
;
4444 * Return end-of-file for a read on a event that is in
4445 * error state (i.e. because it was pinned but it couldn't be
4446 * scheduled on to the CPU at some point).
4448 if (event
->state
== PERF_EVENT_STATE_ERROR
)
4451 if (count
< event
->read_size
)
4454 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
4455 if (read_format
& PERF_FORMAT_GROUP
)
4456 ret
= perf_read_group(event
, read_format
, buf
);
4458 ret
= perf_read_one(event
, read_format
, buf
);
4464 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
4466 struct perf_event
*event
= file
->private_data
;
4467 struct perf_event_context
*ctx
;
4470 ctx
= perf_event_ctx_lock(event
);
4471 ret
= __perf_read(event
, buf
, count
);
4472 perf_event_ctx_unlock(event
, ctx
);
4477 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
4479 struct perf_event
*event
= file
->private_data
;
4480 struct ring_buffer
*rb
;
4481 unsigned int events
= POLLHUP
;
4483 poll_wait(file
, &event
->waitq
, wait
);
4485 if (is_event_hup(event
))
4489 * Pin the event->rb by taking event->mmap_mutex; otherwise
4490 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4492 mutex_lock(&event
->mmap_mutex
);
4495 events
= atomic_xchg(&rb
->poll
, 0);
4496 mutex_unlock(&event
->mmap_mutex
);
4500 static void _perf_event_reset(struct perf_event
*event
)
4502 (void)perf_event_read(event
, false);
4503 local64_set(&event
->count
, 0);
4504 perf_event_update_userpage(event
);
4508 * Holding the top-level event's child_mutex means that any
4509 * descendant process that has inherited this event will block
4510 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4511 * task existence requirements of perf_event_enable/disable.
4513 static void perf_event_for_each_child(struct perf_event
*event
,
4514 void (*func
)(struct perf_event
*))
4516 struct perf_event
*child
;
4518 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
4520 mutex_lock(&event
->child_mutex
);
4522 list_for_each_entry(child
, &event
->child_list
, child_list
)
4524 mutex_unlock(&event
->child_mutex
);
4527 static void perf_event_for_each(struct perf_event
*event
,
4528 void (*func
)(struct perf_event
*))
4530 struct perf_event_context
*ctx
= event
->ctx
;
4531 struct perf_event
*sibling
;
4533 lockdep_assert_held(&ctx
->mutex
);
4535 event
= event
->group_leader
;
4537 perf_event_for_each_child(event
, func
);
4538 list_for_each_entry(sibling
, &event
->sibling_list
, group_entry
)
4539 perf_event_for_each_child(sibling
, func
);
4542 static void __perf_event_period(struct perf_event
*event
,
4543 struct perf_cpu_context
*cpuctx
,
4544 struct perf_event_context
*ctx
,
4547 u64 value
= *((u64
*)info
);
4550 if (event
->attr
.freq
) {
4551 event
->attr
.sample_freq
= value
;
4553 event
->attr
.sample_period
= value
;
4554 event
->hw
.sample_period
= value
;
4557 active
= (event
->state
== PERF_EVENT_STATE_ACTIVE
);
4559 perf_pmu_disable(ctx
->pmu
);
4561 * We could be throttled; unthrottle now to avoid the tick
4562 * trying to unthrottle while we already re-started the event.
4564 if (event
->hw
.interrupts
== MAX_INTERRUPTS
) {
4565 event
->hw
.interrupts
= 0;
4566 perf_log_throttle(event
, 1);
4568 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
4571 local64_set(&event
->hw
.period_left
, 0);
4574 event
->pmu
->start(event
, PERF_EF_RELOAD
);
4575 perf_pmu_enable(ctx
->pmu
);
4579 static int perf_event_period(struct perf_event
*event
, u64 __user
*arg
)
4583 if (!is_sampling_event(event
))
4586 if (copy_from_user(&value
, arg
, sizeof(value
)))
4592 if (event
->attr
.freq
&& value
> sysctl_perf_event_sample_rate
)
4595 event_function_call(event
, __perf_event_period
, &value
);
4600 static const struct file_operations perf_fops
;
4602 static inline int perf_fget_light(int fd
, struct fd
*p
)
4604 struct fd f
= fdget(fd
);
4608 if (f
.file
->f_op
!= &perf_fops
) {
4616 static int perf_event_set_output(struct perf_event
*event
,
4617 struct perf_event
*output_event
);
4618 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
);
4619 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
);
4621 static long _perf_ioctl(struct perf_event
*event
, unsigned int cmd
, unsigned long arg
)
4623 void (*func
)(struct perf_event
*);
4627 case PERF_EVENT_IOC_ENABLE
:
4628 func
= _perf_event_enable
;
4630 case PERF_EVENT_IOC_DISABLE
:
4631 func
= _perf_event_disable
;
4633 case PERF_EVENT_IOC_RESET
:
4634 func
= _perf_event_reset
;
4637 case PERF_EVENT_IOC_REFRESH
:
4638 return _perf_event_refresh(event
, arg
);
4640 case PERF_EVENT_IOC_PERIOD
:
4641 return perf_event_period(event
, (u64 __user
*)arg
);
4643 case PERF_EVENT_IOC_ID
:
4645 u64 id
= primary_event_id(event
);
4647 if (copy_to_user((void __user
*)arg
, &id
, sizeof(id
)))
4652 case PERF_EVENT_IOC_SET_OUTPUT
:
4656 struct perf_event
*output_event
;
4658 ret
= perf_fget_light(arg
, &output
);
4661 output_event
= output
.file
->private_data
;
4662 ret
= perf_event_set_output(event
, output_event
);
4665 ret
= perf_event_set_output(event
, NULL
);
4670 case PERF_EVENT_IOC_SET_FILTER
:
4671 return perf_event_set_filter(event
, (void __user
*)arg
);
4673 case PERF_EVENT_IOC_SET_BPF
:
4674 return perf_event_set_bpf_prog(event
, arg
);
4676 case PERF_EVENT_IOC_PAUSE_OUTPUT
: {
4677 struct ring_buffer
*rb
;
4680 rb
= rcu_dereference(event
->rb
);
4681 if (!rb
|| !rb
->nr_pages
) {
4685 rb_toggle_paused(rb
, !!arg
);
4693 if (flags
& PERF_IOC_FLAG_GROUP
)
4694 perf_event_for_each(event
, func
);
4696 perf_event_for_each_child(event
, func
);
4701 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
4703 struct perf_event
*event
= file
->private_data
;
4704 struct perf_event_context
*ctx
;
4707 ctx
= perf_event_ctx_lock(event
);
4708 ret
= _perf_ioctl(event
, cmd
, arg
);
4709 perf_event_ctx_unlock(event
, ctx
);
4714 #ifdef CONFIG_COMPAT
4715 static long perf_compat_ioctl(struct file
*file
, unsigned int cmd
,
4718 switch (_IOC_NR(cmd
)) {
4719 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER
):
4720 case _IOC_NR(PERF_EVENT_IOC_ID
):
4721 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4722 if (_IOC_SIZE(cmd
) == sizeof(compat_uptr_t
)) {
4723 cmd
&= ~IOCSIZE_MASK
;
4724 cmd
|= sizeof(void *) << IOCSIZE_SHIFT
;
4728 return perf_ioctl(file
, cmd
, arg
);
4731 # define perf_compat_ioctl NULL
4734 int perf_event_task_enable(void)
4736 struct perf_event_context
*ctx
;
4737 struct perf_event
*event
;
4739 mutex_lock(¤t
->perf_event_mutex
);
4740 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
) {
4741 ctx
= perf_event_ctx_lock(event
);
4742 perf_event_for_each_child(event
, _perf_event_enable
);
4743 perf_event_ctx_unlock(event
, ctx
);
4745 mutex_unlock(¤t
->perf_event_mutex
);
4750 int perf_event_task_disable(void)
4752 struct perf_event_context
*ctx
;
4753 struct perf_event
*event
;
4755 mutex_lock(¤t
->perf_event_mutex
);
4756 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
) {
4757 ctx
= perf_event_ctx_lock(event
);
4758 perf_event_for_each_child(event
, _perf_event_disable
);
4759 perf_event_ctx_unlock(event
, ctx
);
4761 mutex_unlock(¤t
->perf_event_mutex
);
4766 static int perf_event_index(struct perf_event
*event
)
4768 if (event
->hw
.state
& PERF_HES_STOPPED
)
4771 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
4774 return event
->pmu
->event_idx(event
);
4777 static void calc_timer_values(struct perf_event
*event
,
4784 *now
= perf_clock();
4785 ctx_time
= event
->shadow_ctx_time
+ *now
;
4786 *enabled
= ctx_time
- event
->tstamp_enabled
;
4787 *running
= ctx_time
- event
->tstamp_running
;
4790 static void perf_event_init_userpage(struct perf_event
*event
)
4792 struct perf_event_mmap_page
*userpg
;
4793 struct ring_buffer
*rb
;
4796 rb
= rcu_dereference(event
->rb
);
4800 userpg
= rb
->user_page
;
4802 /* Allow new userspace to detect that bit 0 is deprecated */
4803 userpg
->cap_bit0_is_deprecated
= 1;
4804 userpg
->size
= offsetof(struct perf_event_mmap_page
, __reserved
);
4805 userpg
->data_offset
= PAGE_SIZE
;
4806 userpg
->data_size
= perf_data_size(rb
);
4812 void __weak
arch_perf_update_userpage(
4813 struct perf_event
*event
, struct perf_event_mmap_page
*userpg
, u64 now
)
4818 * Callers need to ensure there can be no nesting of this function, otherwise
4819 * the seqlock logic goes bad. We can not serialize this because the arch
4820 * code calls this from NMI context.
4822 void perf_event_update_userpage(struct perf_event
*event
)
4824 struct perf_event_mmap_page
*userpg
;
4825 struct ring_buffer
*rb
;
4826 u64 enabled
, running
, now
;
4829 rb
= rcu_dereference(event
->rb
);
4834 * compute total_time_enabled, total_time_running
4835 * based on snapshot values taken when the event
4836 * was last scheduled in.
4838 * we cannot simply called update_context_time()
4839 * because of locking issue as we can be called in
4842 calc_timer_values(event
, &now
, &enabled
, &running
);
4844 userpg
= rb
->user_page
;
4846 * Disable preemption so as to not let the corresponding user-space
4847 * spin too long if we get preempted.
4852 userpg
->index
= perf_event_index(event
);
4853 userpg
->offset
= perf_event_count(event
);
4855 userpg
->offset
-= local64_read(&event
->hw
.prev_count
);
4857 userpg
->time_enabled
= enabled
+
4858 atomic64_read(&event
->child_total_time_enabled
);
4860 userpg
->time_running
= running
+
4861 atomic64_read(&event
->child_total_time_running
);
4863 arch_perf_update_userpage(event
, userpg
, now
);
4872 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
4874 struct perf_event
*event
= vma
->vm_file
->private_data
;
4875 struct ring_buffer
*rb
;
4876 int ret
= VM_FAULT_SIGBUS
;
4878 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
4879 if (vmf
->pgoff
== 0)
4885 rb
= rcu_dereference(event
->rb
);
4889 if (vmf
->pgoff
&& (vmf
->flags
& FAULT_FLAG_WRITE
))
4892 vmf
->page
= perf_mmap_to_page(rb
, vmf
->pgoff
);
4896 get_page(vmf
->page
);
4897 vmf
->page
->mapping
= vma
->vm_file
->f_mapping
;
4898 vmf
->page
->index
= vmf
->pgoff
;
4907 static void ring_buffer_attach(struct perf_event
*event
,
4908 struct ring_buffer
*rb
)
4910 struct ring_buffer
*old_rb
= NULL
;
4911 unsigned long flags
;
4915 * Should be impossible, we set this when removing
4916 * event->rb_entry and wait/clear when adding event->rb_entry.
4918 WARN_ON_ONCE(event
->rcu_pending
);
4921 spin_lock_irqsave(&old_rb
->event_lock
, flags
);
4922 list_del_rcu(&event
->rb_entry
);
4923 spin_unlock_irqrestore(&old_rb
->event_lock
, flags
);
4925 event
->rcu_batches
= get_state_synchronize_rcu();
4926 event
->rcu_pending
= 1;
4930 if (event
->rcu_pending
) {
4931 cond_synchronize_rcu(event
->rcu_batches
);
4932 event
->rcu_pending
= 0;
4935 spin_lock_irqsave(&rb
->event_lock
, flags
);
4936 list_add_rcu(&event
->rb_entry
, &rb
->event_list
);
4937 spin_unlock_irqrestore(&rb
->event_lock
, flags
);
4941 * Avoid racing with perf_mmap_close(AUX): stop the event
4942 * before swizzling the event::rb pointer; if it's getting
4943 * unmapped, its aux_mmap_count will be 0 and it won't
4944 * restart. See the comment in __perf_pmu_output_stop().
4946 * Data will inevitably be lost when set_output is done in
4947 * mid-air, but then again, whoever does it like this is
4948 * not in for the data anyway.
4951 perf_event_stop(event
, 0);
4953 rcu_assign_pointer(event
->rb
, rb
);
4956 ring_buffer_put(old_rb
);
4958 * Since we detached before setting the new rb, so that we
4959 * could attach the new rb, we could have missed a wakeup.
4962 wake_up_all(&event
->waitq
);
4966 static void ring_buffer_wakeup(struct perf_event
*event
)
4968 struct ring_buffer
*rb
;
4971 rb
= rcu_dereference(event
->rb
);
4973 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
)
4974 wake_up_all(&event
->waitq
);
4979 struct ring_buffer
*ring_buffer_get(struct perf_event
*event
)
4981 struct ring_buffer
*rb
;
4984 rb
= rcu_dereference(event
->rb
);
4986 if (!atomic_inc_not_zero(&rb
->refcount
))
4994 void ring_buffer_put(struct ring_buffer
*rb
)
4996 if (!atomic_dec_and_test(&rb
->refcount
))
4999 WARN_ON_ONCE(!list_empty(&rb
->event_list
));
5001 call_rcu(&rb
->rcu_head
, rb_free_rcu
);
5004 static void perf_mmap_open(struct vm_area_struct
*vma
)
5006 struct perf_event
*event
= vma
->vm_file
->private_data
;
5008 atomic_inc(&event
->mmap_count
);
5009 atomic_inc(&event
->rb
->mmap_count
);
5012 atomic_inc(&event
->rb
->aux_mmap_count
);
5014 if (event
->pmu
->event_mapped
)
5015 event
->pmu
->event_mapped(event
);
5018 static void perf_pmu_output_stop(struct perf_event
*event
);
5021 * A buffer can be mmap()ed multiple times; either directly through the same
5022 * event, or through other events by use of perf_event_set_output().
5024 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5025 * the buffer here, where we still have a VM context. This means we need
5026 * to detach all events redirecting to us.
5028 static void perf_mmap_close(struct vm_area_struct
*vma
)
5030 struct perf_event
*event
= vma
->vm_file
->private_data
;
5032 struct ring_buffer
*rb
= ring_buffer_get(event
);
5033 struct user_struct
*mmap_user
= rb
->mmap_user
;
5034 int mmap_locked
= rb
->mmap_locked
;
5035 unsigned long size
= perf_data_size(rb
);
5037 if (event
->pmu
->event_unmapped
)
5038 event
->pmu
->event_unmapped(event
);
5041 * rb->aux_mmap_count will always drop before rb->mmap_count and
5042 * event->mmap_count, so it is ok to use event->mmap_mutex to
5043 * serialize with perf_mmap here.
5045 if (rb_has_aux(rb
) && vma
->vm_pgoff
== rb
->aux_pgoff
&&
5046 atomic_dec_and_mutex_lock(&rb
->aux_mmap_count
, &event
->mmap_mutex
)) {
5048 * Stop all AUX events that are writing to this buffer,
5049 * so that we can free its AUX pages and corresponding PMU
5050 * data. Note that after rb::aux_mmap_count dropped to zero,
5051 * they won't start any more (see perf_aux_output_begin()).
5053 perf_pmu_output_stop(event
);
5055 /* now it's safe to free the pages */
5056 atomic_long_sub(rb
->aux_nr_pages
, &mmap_user
->locked_vm
);
5057 vma
->vm_mm
->pinned_vm
-= rb
->aux_mmap_locked
;
5059 /* this has to be the last one */
5061 WARN_ON_ONCE(atomic_read(&rb
->aux_refcount
));
5063 mutex_unlock(&event
->mmap_mutex
);
5066 atomic_dec(&rb
->mmap_count
);
5068 if (!atomic_dec_and_mutex_lock(&event
->mmap_count
, &event
->mmap_mutex
))
5071 ring_buffer_attach(event
, NULL
);
5072 mutex_unlock(&event
->mmap_mutex
);
5074 /* If there's still other mmap()s of this buffer, we're done. */
5075 if (atomic_read(&rb
->mmap_count
))
5079 * No other mmap()s, detach from all other events that might redirect
5080 * into the now unreachable buffer. Somewhat complicated by the
5081 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5085 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
) {
5086 if (!atomic_long_inc_not_zero(&event
->refcount
)) {
5088 * This event is en-route to free_event() which will
5089 * detach it and remove it from the list.
5095 mutex_lock(&event
->mmap_mutex
);
5097 * Check we didn't race with perf_event_set_output() which can
5098 * swizzle the rb from under us while we were waiting to
5099 * acquire mmap_mutex.
5101 * If we find a different rb; ignore this event, a next
5102 * iteration will no longer find it on the list. We have to
5103 * still restart the iteration to make sure we're not now
5104 * iterating the wrong list.
5106 if (event
->rb
== rb
)
5107 ring_buffer_attach(event
, NULL
);
5109 mutex_unlock(&event
->mmap_mutex
);
5113 * Restart the iteration; either we're on the wrong list or
5114 * destroyed its integrity by doing a deletion.
5121 * It could be there's still a few 0-ref events on the list; they'll
5122 * get cleaned up by free_event() -- they'll also still have their
5123 * ref on the rb and will free it whenever they are done with it.
5125 * Aside from that, this buffer is 'fully' detached and unmapped,
5126 * undo the VM accounting.
5129 atomic_long_sub((size
>> PAGE_SHIFT
) + 1, &mmap_user
->locked_vm
);
5130 vma
->vm_mm
->pinned_vm
-= mmap_locked
;
5131 free_uid(mmap_user
);
5134 ring_buffer_put(rb
); /* could be last */
5137 static const struct vm_operations_struct perf_mmap_vmops
= {
5138 .open
= perf_mmap_open
,
5139 .close
= perf_mmap_close
, /* non mergable */
5140 .fault
= perf_mmap_fault
,
5141 .page_mkwrite
= perf_mmap_fault
,
5144 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
5146 struct perf_event
*event
= file
->private_data
;
5147 unsigned long user_locked
, user_lock_limit
;
5148 struct user_struct
*user
= current_user();
5149 unsigned long locked
, lock_limit
;
5150 struct ring_buffer
*rb
= NULL
;
5151 unsigned long vma_size
;
5152 unsigned long nr_pages
;
5153 long user_extra
= 0, extra
= 0;
5154 int ret
= 0, flags
= 0;
5157 * Don't allow mmap() of inherited per-task counters. This would
5158 * create a performance issue due to all children writing to the
5161 if (event
->cpu
== -1 && event
->attr
.inherit
)
5164 if (!(vma
->vm_flags
& VM_SHARED
))
5167 vma_size
= vma
->vm_end
- vma
->vm_start
;
5169 if (vma
->vm_pgoff
== 0) {
5170 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
5173 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5174 * mapped, all subsequent mappings should have the same size
5175 * and offset. Must be above the normal perf buffer.
5177 u64 aux_offset
, aux_size
;
5182 nr_pages
= vma_size
/ PAGE_SIZE
;
5184 mutex_lock(&event
->mmap_mutex
);
5191 aux_offset
= ACCESS_ONCE(rb
->user_page
->aux_offset
);
5192 aux_size
= ACCESS_ONCE(rb
->user_page
->aux_size
);
5194 if (aux_offset
< perf_data_size(rb
) + PAGE_SIZE
)
5197 if (aux_offset
!= vma
->vm_pgoff
<< PAGE_SHIFT
)
5200 /* already mapped with a different offset */
5201 if (rb_has_aux(rb
) && rb
->aux_pgoff
!= vma
->vm_pgoff
)
5204 if (aux_size
!= vma_size
|| aux_size
!= nr_pages
* PAGE_SIZE
)
5207 /* already mapped with a different size */
5208 if (rb_has_aux(rb
) && rb
->aux_nr_pages
!= nr_pages
)
5211 if (!is_power_of_2(nr_pages
))
5214 if (!atomic_inc_not_zero(&rb
->mmap_count
))
5217 if (rb_has_aux(rb
)) {
5218 atomic_inc(&rb
->aux_mmap_count
);
5223 atomic_set(&rb
->aux_mmap_count
, 1);
5224 user_extra
= nr_pages
;
5230 * If we have rb pages ensure they're a power-of-two number, so we
5231 * can do bitmasks instead of modulo.
5233 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
5236 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
5239 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
5241 mutex_lock(&event
->mmap_mutex
);
5243 if (event
->rb
->nr_pages
!= nr_pages
) {
5248 if (!atomic_inc_not_zero(&event
->rb
->mmap_count
)) {
5250 * Raced against perf_mmap_close() through
5251 * perf_event_set_output(). Try again, hope for better
5254 mutex_unlock(&event
->mmap_mutex
);
5261 user_extra
= nr_pages
+ 1;
5264 user_lock_limit
= sysctl_perf_event_mlock
>> (PAGE_SHIFT
- 10);
5267 * Increase the limit linearly with more CPUs:
5269 user_lock_limit
*= num_online_cpus();
5271 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
5273 if (user_locked
> user_lock_limit
)
5274 extra
= user_locked
- user_lock_limit
;
5276 lock_limit
= rlimit(RLIMIT_MEMLOCK
);
5277 lock_limit
>>= PAGE_SHIFT
;
5278 locked
= vma
->vm_mm
->pinned_vm
+ extra
;
5280 if ((locked
> lock_limit
) && perf_paranoid_tracepoint_raw() &&
5281 !capable(CAP_IPC_LOCK
)) {
5286 WARN_ON(!rb
&& event
->rb
);
5288 if (vma
->vm_flags
& VM_WRITE
)
5289 flags
|= RING_BUFFER_WRITABLE
;
5292 rb
= rb_alloc(nr_pages
,
5293 event
->attr
.watermark
? event
->attr
.wakeup_watermark
: 0,
5301 atomic_set(&rb
->mmap_count
, 1);
5302 rb
->mmap_user
= get_current_user();
5303 rb
->mmap_locked
= extra
;
5305 ring_buffer_attach(event
, rb
);
5307 perf_event_init_userpage(event
);
5308 perf_event_update_userpage(event
);
5310 ret
= rb_alloc_aux(rb
, event
, vma
->vm_pgoff
, nr_pages
,
5311 event
->attr
.aux_watermark
, flags
);
5313 rb
->aux_mmap_locked
= extra
;
5318 atomic_long_add(user_extra
, &user
->locked_vm
);
5319 vma
->vm_mm
->pinned_vm
+= extra
;
5321 atomic_inc(&event
->mmap_count
);
5323 atomic_dec(&rb
->mmap_count
);
5326 mutex_unlock(&event
->mmap_mutex
);
5329 * Since pinned accounting is per vm we cannot allow fork() to copy our
5332 vma
->vm_flags
|= VM_DONTCOPY
| VM_DONTEXPAND
| VM_DONTDUMP
;
5333 vma
->vm_ops
= &perf_mmap_vmops
;
5335 if (event
->pmu
->event_mapped
)
5336 event
->pmu
->event_mapped(event
);
5341 static int perf_fasync(int fd
, struct file
*filp
, int on
)
5343 struct inode
*inode
= file_inode(filp
);
5344 struct perf_event
*event
= filp
->private_data
;
5348 retval
= fasync_helper(fd
, filp
, on
, &event
->fasync
);
5349 inode_unlock(inode
);
5357 static const struct file_operations perf_fops
= {
5358 .llseek
= no_llseek
,
5359 .release
= perf_release
,
5362 .unlocked_ioctl
= perf_ioctl
,
5363 .compat_ioctl
= perf_compat_ioctl
,
5365 .fasync
= perf_fasync
,
5371 * If there's data, ensure we set the poll() state and publish everything
5372 * to user-space before waking everybody up.
5375 static inline struct fasync_struct
**perf_event_fasync(struct perf_event
*event
)
5377 /* only the parent has fasync state */
5379 event
= event
->parent
;
5380 return &event
->fasync
;
5383 void perf_event_wakeup(struct perf_event
*event
)
5385 ring_buffer_wakeup(event
);
5387 if (event
->pending_kill
) {
5388 kill_fasync(perf_event_fasync(event
), SIGIO
, event
->pending_kill
);
5389 event
->pending_kill
= 0;
5393 static void perf_pending_event(struct irq_work
*entry
)
5395 struct perf_event
*event
= container_of(entry
,
5396 struct perf_event
, pending
);
5399 rctx
= perf_swevent_get_recursion_context();
5401 * If we 'fail' here, that's OK, it means recursion is already disabled
5402 * and we won't recurse 'further'.
5405 if (event
->pending_disable
) {
5406 event
->pending_disable
= 0;
5407 perf_event_disable_local(event
);
5410 if (event
->pending_wakeup
) {
5411 event
->pending_wakeup
= 0;
5412 perf_event_wakeup(event
);
5416 perf_swevent_put_recursion_context(rctx
);
5420 * We assume there is only KVM supporting the callbacks.
5421 * Later on, we might change it to a list if there is
5422 * another virtualization implementation supporting the callbacks.
5424 struct perf_guest_info_callbacks
*perf_guest_cbs
;
5426 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
5428 perf_guest_cbs
= cbs
;
5431 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks
);
5433 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
5435 perf_guest_cbs
= NULL
;
5438 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks
);
5441 perf_output_sample_regs(struct perf_output_handle
*handle
,
5442 struct pt_regs
*regs
, u64 mask
)
5445 DECLARE_BITMAP(_mask
, 64);
5447 bitmap_from_u64(_mask
, mask
);
5448 for_each_set_bit(bit
, _mask
, sizeof(mask
) * BITS_PER_BYTE
) {
5451 val
= perf_reg_value(regs
, bit
);
5452 perf_output_put(handle
, val
);
5456 static void perf_sample_regs_user(struct perf_regs
*regs_user
,
5457 struct pt_regs
*regs
,
5458 struct pt_regs
*regs_user_copy
)
5460 if (user_mode(regs
)) {
5461 regs_user
->abi
= perf_reg_abi(current
);
5462 regs_user
->regs
= regs
;
5463 } else if (current
->mm
) {
5464 perf_get_regs_user(regs_user
, regs
, regs_user_copy
);
5466 regs_user
->abi
= PERF_SAMPLE_REGS_ABI_NONE
;
5467 regs_user
->regs
= NULL
;
5471 static void perf_sample_regs_intr(struct perf_regs
*regs_intr
,
5472 struct pt_regs
*regs
)
5474 regs_intr
->regs
= regs
;
5475 regs_intr
->abi
= perf_reg_abi(current
);
5480 * Get remaining task size from user stack pointer.
5482 * It'd be better to take stack vma map and limit this more
5483 * precisly, but there's no way to get it safely under interrupt,
5484 * so using TASK_SIZE as limit.
5486 static u64
perf_ustack_task_size(struct pt_regs
*regs
)
5488 unsigned long addr
= perf_user_stack_pointer(regs
);
5490 if (!addr
|| addr
>= TASK_SIZE
)
5493 return TASK_SIZE
- addr
;
5497 perf_sample_ustack_size(u16 stack_size
, u16 header_size
,
5498 struct pt_regs
*regs
)
5502 /* No regs, no stack pointer, no dump. */
5507 * Check if we fit in with the requested stack size into the:
5509 * If we don't, we limit the size to the TASK_SIZE.
5511 * - remaining sample size
5512 * If we don't, we customize the stack size to
5513 * fit in to the remaining sample size.
5516 task_size
= min((u64
) USHRT_MAX
, perf_ustack_task_size(regs
));
5517 stack_size
= min(stack_size
, (u16
) task_size
);
5519 /* Current header size plus static size and dynamic size. */
5520 header_size
+= 2 * sizeof(u64
);
5522 /* Do we fit in with the current stack dump size? */
5523 if ((u16
) (header_size
+ stack_size
) < header_size
) {
5525 * If we overflow the maximum size for the sample,
5526 * we customize the stack dump size to fit in.
5528 stack_size
= USHRT_MAX
- header_size
- sizeof(u64
);
5529 stack_size
= round_up(stack_size
, sizeof(u64
));
5536 perf_output_sample_ustack(struct perf_output_handle
*handle
, u64 dump_size
,
5537 struct pt_regs
*regs
)
5539 /* Case of a kernel thread, nothing to dump */
5542 perf_output_put(handle
, size
);
5551 * - the size requested by user or the best one we can fit
5552 * in to the sample max size
5554 * - user stack dump data
5556 * - the actual dumped size
5560 perf_output_put(handle
, dump_size
);
5563 sp
= perf_user_stack_pointer(regs
);
5564 rem
= __output_copy_user(handle
, (void *) sp
, dump_size
);
5565 dyn_size
= dump_size
- rem
;
5567 perf_output_skip(handle
, rem
);
5570 perf_output_put(handle
, dyn_size
);
5574 static void __perf_event_header__init_id(struct perf_event_header
*header
,
5575 struct perf_sample_data
*data
,
5576 struct perf_event
*event
)
5578 u64 sample_type
= event
->attr
.sample_type
;
5580 data
->type
= sample_type
;
5581 header
->size
+= event
->id_header_size
;
5583 if (sample_type
& PERF_SAMPLE_TID
) {
5584 /* namespace issues */
5585 data
->tid_entry
.pid
= perf_event_pid(event
, current
);
5586 data
->tid_entry
.tid
= perf_event_tid(event
, current
);
5589 if (sample_type
& PERF_SAMPLE_TIME
)
5590 data
->time
= perf_event_clock(event
);
5592 if (sample_type
& (PERF_SAMPLE_ID
| PERF_SAMPLE_IDENTIFIER
))
5593 data
->id
= primary_event_id(event
);
5595 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
5596 data
->stream_id
= event
->id
;
5598 if (sample_type
& PERF_SAMPLE_CPU
) {
5599 data
->cpu_entry
.cpu
= raw_smp_processor_id();
5600 data
->cpu_entry
.reserved
= 0;
5604 void perf_event_header__init_id(struct perf_event_header
*header
,
5605 struct perf_sample_data
*data
,
5606 struct perf_event
*event
)
5608 if (event
->attr
.sample_id_all
)
5609 __perf_event_header__init_id(header
, data
, event
);
5612 static void __perf_event__output_id_sample(struct perf_output_handle
*handle
,
5613 struct perf_sample_data
*data
)
5615 u64 sample_type
= data
->type
;
5617 if (sample_type
& PERF_SAMPLE_TID
)
5618 perf_output_put(handle
, data
->tid_entry
);
5620 if (sample_type
& PERF_SAMPLE_TIME
)
5621 perf_output_put(handle
, data
->time
);
5623 if (sample_type
& PERF_SAMPLE_ID
)
5624 perf_output_put(handle
, data
->id
);
5626 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
5627 perf_output_put(handle
, data
->stream_id
);
5629 if (sample_type
& PERF_SAMPLE_CPU
)
5630 perf_output_put(handle
, data
->cpu_entry
);
5632 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
5633 perf_output_put(handle
, data
->id
);
5636 void perf_event__output_id_sample(struct perf_event
*event
,
5637 struct perf_output_handle
*handle
,
5638 struct perf_sample_data
*sample
)
5640 if (event
->attr
.sample_id_all
)
5641 __perf_event__output_id_sample(handle
, sample
);
5644 static void perf_output_read_one(struct perf_output_handle
*handle
,
5645 struct perf_event
*event
,
5646 u64 enabled
, u64 running
)
5648 u64 read_format
= event
->attr
.read_format
;
5652 values
[n
++] = perf_event_count(event
);
5653 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
5654 values
[n
++] = enabled
+
5655 atomic64_read(&event
->child_total_time_enabled
);
5657 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
5658 values
[n
++] = running
+
5659 atomic64_read(&event
->child_total_time_running
);
5661 if (read_format
& PERF_FORMAT_ID
)
5662 values
[n
++] = primary_event_id(event
);
5664 __output_copy(handle
, values
, n
* sizeof(u64
));
5668 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5670 static void perf_output_read_group(struct perf_output_handle
*handle
,
5671 struct perf_event
*event
,
5672 u64 enabled
, u64 running
)
5674 struct perf_event
*leader
= event
->group_leader
, *sub
;
5675 u64 read_format
= event
->attr
.read_format
;
5679 values
[n
++] = 1 + leader
->nr_siblings
;
5681 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
5682 values
[n
++] = enabled
;
5684 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
5685 values
[n
++] = running
;
5687 if (leader
!= event
)
5688 leader
->pmu
->read(leader
);
5690 values
[n
++] = perf_event_count(leader
);
5691 if (read_format
& PERF_FORMAT_ID
)
5692 values
[n
++] = primary_event_id(leader
);
5694 __output_copy(handle
, values
, n
* sizeof(u64
));
5696 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
5699 if ((sub
!= event
) &&
5700 (sub
->state
== PERF_EVENT_STATE_ACTIVE
))
5701 sub
->pmu
->read(sub
);
5703 values
[n
++] = perf_event_count(sub
);
5704 if (read_format
& PERF_FORMAT_ID
)
5705 values
[n
++] = primary_event_id(sub
);
5707 __output_copy(handle
, values
, n
* sizeof(u64
));
5711 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5712 PERF_FORMAT_TOTAL_TIME_RUNNING)
5714 static void perf_output_read(struct perf_output_handle
*handle
,
5715 struct perf_event
*event
)
5717 u64 enabled
= 0, running
= 0, now
;
5718 u64 read_format
= event
->attr
.read_format
;
5721 * compute total_time_enabled, total_time_running
5722 * based on snapshot values taken when the event
5723 * was last scheduled in.
5725 * we cannot simply called update_context_time()
5726 * because of locking issue as we are called in
5729 if (read_format
& PERF_FORMAT_TOTAL_TIMES
)
5730 calc_timer_values(event
, &now
, &enabled
, &running
);
5732 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
)
5733 perf_output_read_group(handle
, event
, enabled
, running
);
5735 perf_output_read_one(handle
, event
, enabled
, running
);
5738 void perf_output_sample(struct perf_output_handle
*handle
,
5739 struct perf_event_header
*header
,
5740 struct perf_sample_data
*data
,
5741 struct perf_event
*event
)
5743 u64 sample_type
= data
->type
;
5745 perf_output_put(handle
, *header
);
5747 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
5748 perf_output_put(handle
, data
->id
);
5750 if (sample_type
& PERF_SAMPLE_IP
)
5751 perf_output_put(handle
, data
->ip
);
5753 if (sample_type
& PERF_SAMPLE_TID
)
5754 perf_output_put(handle
, data
->tid_entry
);
5756 if (sample_type
& PERF_SAMPLE_TIME
)
5757 perf_output_put(handle
, data
->time
);
5759 if (sample_type
& PERF_SAMPLE_ADDR
)
5760 perf_output_put(handle
, data
->addr
);
5762 if (sample_type
& PERF_SAMPLE_ID
)
5763 perf_output_put(handle
, data
->id
);
5765 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
5766 perf_output_put(handle
, data
->stream_id
);
5768 if (sample_type
& PERF_SAMPLE_CPU
)
5769 perf_output_put(handle
, data
->cpu_entry
);
5771 if (sample_type
& PERF_SAMPLE_PERIOD
)
5772 perf_output_put(handle
, data
->period
);
5774 if (sample_type
& PERF_SAMPLE_READ
)
5775 perf_output_read(handle
, event
);
5777 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
5778 if (data
->callchain
) {
5781 if (data
->callchain
)
5782 size
+= data
->callchain
->nr
;
5784 size
*= sizeof(u64
);
5786 __output_copy(handle
, data
->callchain
, size
);
5789 perf_output_put(handle
, nr
);
5793 if (sample_type
& PERF_SAMPLE_RAW
) {
5794 struct perf_raw_record
*raw
= data
->raw
;
5797 struct perf_raw_frag
*frag
= &raw
->frag
;
5799 perf_output_put(handle
, raw
->size
);
5802 __output_custom(handle
, frag
->copy
,
5803 frag
->data
, frag
->size
);
5805 __output_copy(handle
, frag
->data
,
5808 if (perf_raw_frag_last(frag
))
5813 __output_skip(handle
, NULL
, frag
->pad
);
5819 .size
= sizeof(u32
),
5822 perf_output_put(handle
, raw
);
5826 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
5827 if (data
->br_stack
) {
5830 size
= data
->br_stack
->nr
5831 * sizeof(struct perf_branch_entry
);
5833 perf_output_put(handle
, data
->br_stack
->nr
);
5834 perf_output_copy(handle
, data
->br_stack
->entries
, size
);
5837 * we always store at least the value of nr
5840 perf_output_put(handle
, nr
);
5844 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
5845 u64 abi
= data
->regs_user
.abi
;
5848 * If there are no regs to dump, notice it through
5849 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5851 perf_output_put(handle
, abi
);
5854 u64 mask
= event
->attr
.sample_regs_user
;
5855 perf_output_sample_regs(handle
,
5856 data
->regs_user
.regs
,
5861 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
5862 perf_output_sample_ustack(handle
,
5863 data
->stack_user_size
,
5864 data
->regs_user
.regs
);
5867 if (sample_type
& PERF_SAMPLE_WEIGHT
)
5868 perf_output_put(handle
, data
->weight
);
5870 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
5871 perf_output_put(handle
, data
->data_src
.val
);
5873 if (sample_type
& PERF_SAMPLE_TRANSACTION
)
5874 perf_output_put(handle
, data
->txn
);
5876 if (sample_type
& PERF_SAMPLE_REGS_INTR
) {
5877 u64 abi
= data
->regs_intr
.abi
;
5879 * If there are no regs to dump, notice it through
5880 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5882 perf_output_put(handle
, abi
);
5885 u64 mask
= event
->attr
.sample_regs_intr
;
5887 perf_output_sample_regs(handle
,
5888 data
->regs_intr
.regs
,
5893 if (!event
->attr
.watermark
) {
5894 int wakeup_events
= event
->attr
.wakeup_events
;
5896 if (wakeup_events
) {
5897 struct ring_buffer
*rb
= handle
->rb
;
5898 int events
= local_inc_return(&rb
->events
);
5900 if (events
>= wakeup_events
) {
5901 local_sub(wakeup_events
, &rb
->events
);
5902 local_inc(&rb
->wakeup
);
5908 void perf_prepare_sample(struct perf_event_header
*header
,
5909 struct perf_sample_data
*data
,
5910 struct perf_event
*event
,
5911 struct pt_regs
*regs
)
5913 u64 sample_type
= event
->attr
.sample_type
;
5915 header
->type
= PERF_RECORD_SAMPLE
;
5916 header
->size
= sizeof(*header
) + event
->header_size
;
5919 header
->misc
|= perf_misc_flags(regs
);
5921 __perf_event_header__init_id(header
, data
, event
);
5923 if (sample_type
& PERF_SAMPLE_IP
)
5924 data
->ip
= perf_instruction_pointer(regs
);
5926 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
5929 data
->callchain
= perf_callchain(event
, regs
);
5931 if (data
->callchain
)
5932 size
+= data
->callchain
->nr
;
5934 header
->size
+= size
* sizeof(u64
);
5937 if (sample_type
& PERF_SAMPLE_RAW
) {
5938 struct perf_raw_record
*raw
= data
->raw
;
5942 struct perf_raw_frag
*frag
= &raw
->frag
;
5947 if (perf_raw_frag_last(frag
))
5952 size
= round_up(sum
+ sizeof(u32
), sizeof(u64
));
5953 raw
->size
= size
- sizeof(u32
);
5954 frag
->pad
= raw
->size
- sum
;
5959 header
->size
+= size
;
5962 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
5963 int size
= sizeof(u64
); /* nr */
5964 if (data
->br_stack
) {
5965 size
+= data
->br_stack
->nr
5966 * sizeof(struct perf_branch_entry
);
5968 header
->size
+= size
;
5971 if (sample_type
& (PERF_SAMPLE_REGS_USER
| PERF_SAMPLE_STACK_USER
))
5972 perf_sample_regs_user(&data
->regs_user
, regs
,
5973 &data
->regs_user_copy
);
5975 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
5976 /* regs dump ABI info */
5977 int size
= sizeof(u64
);
5979 if (data
->regs_user
.regs
) {
5980 u64 mask
= event
->attr
.sample_regs_user
;
5981 size
+= hweight64(mask
) * sizeof(u64
);
5984 header
->size
+= size
;
5987 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
5989 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5990 * processed as the last one or have additional check added
5991 * in case new sample type is added, because we could eat
5992 * up the rest of the sample size.
5994 u16 stack_size
= event
->attr
.sample_stack_user
;
5995 u16 size
= sizeof(u64
);
5997 stack_size
= perf_sample_ustack_size(stack_size
, header
->size
,
5998 data
->regs_user
.regs
);
6001 * If there is something to dump, add space for the dump
6002 * itself and for the field that tells the dynamic size,
6003 * which is how many have been actually dumped.
6006 size
+= sizeof(u64
) + stack_size
;
6008 data
->stack_user_size
= stack_size
;
6009 header
->size
+= size
;
6012 if (sample_type
& PERF_SAMPLE_REGS_INTR
) {
6013 /* regs dump ABI info */
6014 int size
= sizeof(u64
);
6016 perf_sample_regs_intr(&data
->regs_intr
, regs
);
6018 if (data
->regs_intr
.regs
) {
6019 u64 mask
= event
->attr
.sample_regs_intr
;
6021 size
+= hweight64(mask
) * sizeof(u64
);
6024 header
->size
+= size
;
6028 static void __always_inline
6029 __perf_event_output(struct perf_event
*event
,
6030 struct perf_sample_data
*data
,
6031 struct pt_regs
*regs
,
6032 int (*output_begin
)(struct perf_output_handle
*,
6033 struct perf_event
*,
6036 struct perf_output_handle handle
;
6037 struct perf_event_header header
;
6039 /* protect the callchain buffers */
6042 perf_prepare_sample(&header
, data
, event
, regs
);
6044 if (output_begin(&handle
, event
, header
.size
))
6047 perf_output_sample(&handle
, &header
, data
, event
);
6049 perf_output_end(&handle
);
6056 perf_event_output_forward(struct perf_event
*event
,
6057 struct perf_sample_data
*data
,
6058 struct pt_regs
*regs
)
6060 __perf_event_output(event
, data
, regs
, perf_output_begin_forward
);
6064 perf_event_output_backward(struct perf_event
*event
,
6065 struct perf_sample_data
*data
,
6066 struct pt_regs
*regs
)
6068 __perf_event_output(event
, data
, regs
, perf_output_begin_backward
);
6072 perf_event_output(struct perf_event
*event
,
6073 struct perf_sample_data
*data
,
6074 struct pt_regs
*regs
)
6076 __perf_event_output(event
, data
, regs
, perf_output_begin
);
6083 struct perf_read_event
{
6084 struct perf_event_header header
;
6091 perf_event_read_event(struct perf_event
*event
,
6092 struct task_struct
*task
)
6094 struct perf_output_handle handle
;
6095 struct perf_sample_data sample
;
6096 struct perf_read_event read_event
= {
6098 .type
= PERF_RECORD_READ
,
6100 .size
= sizeof(read_event
) + event
->read_size
,
6102 .pid
= perf_event_pid(event
, task
),
6103 .tid
= perf_event_tid(event
, task
),
6107 perf_event_header__init_id(&read_event
.header
, &sample
, event
);
6108 ret
= perf_output_begin(&handle
, event
, read_event
.header
.size
);
6112 perf_output_put(&handle
, read_event
);
6113 perf_output_read(&handle
, event
);
6114 perf_event__output_id_sample(event
, &handle
, &sample
);
6116 perf_output_end(&handle
);
6119 typedef void (perf_iterate_f
)(struct perf_event
*event
, void *data
);
6122 perf_iterate_ctx(struct perf_event_context
*ctx
,
6123 perf_iterate_f output
,
6124 void *data
, bool all
)
6126 struct perf_event
*event
;
6128 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
6130 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
6132 if (!event_filter_match(event
))
6136 output(event
, data
);
6140 static void perf_iterate_sb_cpu(perf_iterate_f output
, void *data
)
6142 struct pmu_event_list
*pel
= this_cpu_ptr(&pmu_sb_events
);
6143 struct perf_event
*event
;
6145 list_for_each_entry_rcu(event
, &pel
->list
, sb_list
) {
6147 * Skip events that are not fully formed yet; ensure that
6148 * if we observe event->ctx, both event and ctx will be
6149 * complete enough. See perf_install_in_context().
6151 if (!smp_load_acquire(&event
->ctx
))
6154 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
6156 if (!event_filter_match(event
))
6158 output(event
, data
);
6163 * Iterate all events that need to receive side-band events.
6165 * For new callers; ensure that account_pmu_sb_event() includes
6166 * your event, otherwise it might not get delivered.
6169 perf_iterate_sb(perf_iterate_f output
, void *data
,
6170 struct perf_event_context
*task_ctx
)
6172 struct perf_event_context
*ctx
;
6179 * If we have task_ctx != NULL we only notify the task context itself.
6180 * The task_ctx is set only for EXIT events before releasing task
6184 perf_iterate_ctx(task_ctx
, output
, data
, false);
6188 perf_iterate_sb_cpu(output
, data
);
6190 for_each_task_context_nr(ctxn
) {
6191 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
6193 perf_iterate_ctx(ctx
, output
, data
, false);
6201 * Clear all file-based filters at exec, they'll have to be
6202 * re-instated when/if these objects are mmapped again.
6204 static void perf_event_addr_filters_exec(struct perf_event
*event
, void *data
)
6206 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
6207 struct perf_addr_filter
*filter
;
6208 unsigned int restart
= 0, count
= 0;
6209 unsigned long flags
;
6211 if (!has_addr_filter(event
))
6214 raw_spin_lock_irqsave(&ifh
->lock
, flags
);
6215 list_for_each_entry(filter
, &ifh
->list
, entry
) {
6216 if (filter
->inode
) {
6217 event
->addr_filters_offs
[count
] = 0;
6225 event
->addr_filters_gen
++;
6226 raw_spin_unlock_irqrestore(&ifh
->lock
, flags
);
6229 perf_event_stop(event
, 1);
6232 void perf_event_exec(void)
6234 struct perf_event_context
*ctx
;
6238 for_each_task_context_nr(ctxn
) {
6239 ctx
= current
->perf_event_ctxp
[ctxn
];
6243 perf_event_enable_on_exec(ctxn
);
6245 perf_iterate_ctx(ctx
, perf_event_addr_filters_exec
, NULL
,
6251 struct remote_output
{
6252 struct ring_buffer
*rb
;
6256 static void __perf_event_output_stop(struct perf_event
*event
, void *data
)
6258 struct perf_event
*parent
= event
->parent
;
6259 struct remote_output
*ro
= data
;
6260 struct ring_buffer
*rb
= ro
->rb
;
6261 struct stop_event_data sd
= {
6265 if (!has_aux(event
))
6272 * In case of inheritance, it will be the parent that links to the
6273 * ring-buffer, but it will be the child that's actually using it.
6275 * We are using event::rb to determine if the event should be stopped,
6276 * however this may race with ring_buffer_attach() (through set_output),
6277 * which will make us skip the event that actually needs to be stopped.
6278 * So ring_buffer_attach() has to stop an aux event before re-assigning
6281 if (rcu_dereference(parent
->rb
) == rb
)
6282 ro
->err
= __perf_event_stop(&sd
);
6285 static int __perf_pmu_output_stop(void *info
)
6287 struct perf_event
*event
= info
;
6288 struct pmu
*pmu
= event
->pmu
;
6289 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
6290 struct remote_output ro
= {
6295 perf_iterate_ctx(&cpuctx
->ctx
, __perf_event_output_stop
, &ro
, false);
6296 if (cpuctx
->task_ctx
)
6297 perf_iterate_ctx(cpuctx
->task_ctx
, __perf_event_output_stop
,
6304 static void perf_pmu_output_stop(struct perf_event
*event
)
6306 struct perf_event
*iter
;
6311 list_for_each_entry_rcu(iter
, &event
->rb
->event_list
, rb_entry
) {
6313 * For per-CPU events, we need to make sure that neither they
6314 * nor their children are running; for cpu==-1 events it's
6315 * sufficient to stop the event itself if it's active, since
6316 * it can't have children.
6320 cpu
= READ_ONCE(iter
->oncpu
);
6325 err
= cpu_function_call(cpu
, __perf_pmu_output_stop
, event
);
6326 if (err
== -EAGAIN
) {
6335 * task tracking -- fork/exit
6337 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6340 struct perf_task_event
{
6341 struct task_struct
*task
;
6342 struct perf_event_context
*task_ctx
;
6345 struct perf_event_header header
;
6355 static int perf_event_task_match(struct perf_event
*event
)
6357 return event
->attr
.comm
|| event
->attr
.mmap
||
6358 event
->attr
.mmap2
|| event
->attr
.mmap_data
||
6362 static void perf_event_task_output(struct perf_event
*event
,
6365 struct perf_task_event
*task_event
= data
;
6366 struct perf_output_handle handle
;
6367 struct perf_sample_data sample
;
6368 struct task_struct
*task
= task_event
->task
;
6369 int ret
, size
= task_event
->event_id
.header
.size
;
6371 if (!perf_event_task_match(event
))
6374 perf_event_header__init_id(&task_event
->event_id
.header
, &sample
, event
);
6376 ret
= perf_output_begin(&handle
, event
,
6377 task_event
->event_id
.header
.size
);
6381 task_event
->event_id
.pid
= perf_event_pid(event
, task
);
6382 task_event
->event_id
.ppid
= perf_event_pid(event
, current
);
6384 task_event
->event_id
.tid
= perf_event_tid(event
, task
);
6385 task_event
->event_id
.ptid
= perf_event_tid(event
, current
);
6387 task_event
->event_id
.time
= perf_event_clock(event
);
6389 perf_output_put(&handle
, task_event
->event_id
);
6391 perf_event__output_id_sample(event
, &handle
, &sample
);
6393 perf_output_end(&handle
);
6395 task_event
->event_id
.header
.size
= size
;
6398 static void perf_event_task(struct task_struct
*task
,
6399 struct perf_event_context
*task_ctx
,
6402 struct perf_task_event task_event
;
6404 if (!atomic_read(&nr_comm_events
) &&
6405 !atomic_read(&nr_mmap_events
) &&
6406 !atomic_read(&nr_task_events
))
6409 task_event
= (struct perf_task_event
){
6411 .task_ctx
= task_ctx
,
6414 .type
= new ? PERF_RECORD_FORK
: PERF_RECORD_EXIT
,
6416 .size
= sizeof(task_event
.event_id
),
6426 perf_iterate_sb(perf_event_task_output
,
6431 void perf_event_fork(struct task_struct
*task
)
6433 perf_event_task(task
, NULL
, 1);
6440 struct perf_comm_event
{
6441 struct task_struct
*task
;
6446 struct perf_event_header header
;
6453 static int perf_event_comm_match(struct perf_event
*event
)
6455 return event
->attr
.comm
;
6458 static void perf_event_comm_output(struct perf_event
*event
,
6461 struct perf_comm_event
*comm_event
= data
;
6462 struct perf_output_handle handle
;
6463 struct perf_sample_data sample
;
6464 int size
= comm_event
->event_id
.header
.size
;
6467 if (!perf_event_comm_match(event
))
6470 perf_event_header__init_id(&comm_event
->event_id
.header
, &sample
, event
);
6471 ret
= perf_output_begin(&handle
, event
,
6472 comm_event
->event_id
.header
.size
);
6477 comm_event
->event_id
.pid
= perf_event_pid(event
, comm_event
->task
);
6478 comm_event
->event_id
.tid
= perf_event_tid(event
, comm_event
->task
);
6480 perf_output_put(&handle
, comm_event
->event_id
);
6481 __output_copy(&handle
, comm_event
->comm
,
6482 comm_event
->comm_size
);
6484 perf_event__output_id_sample(event
, &handle
, &sample
);
6486 perf_output_end(&handle
);
6488 comm_event
->event_id
.header
.size
= size
;
6491 static void perf_event_comm_event(struct perf_comm_event
*comm_event
)
6493 char comm
[TASK_COMM_LEN
];
6496 memset(comm
, 0, sizeof(comm
));
6497 strlcpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
6498 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
6500 comm_event
->comm
= comm
;
6501 comm_event
->comm_size
= size
;
6503 comm_event
->event_id
.header
.size
= sizeof(comm_event
->event_id
) + size
;
6505 perf_iterate_sb(perf_event_comm_output
,
6510 void perf_event_comm(struct task_struct
*task
, bool exec
)
6512 struct perf_comm_event comm_event
;
6514 if (!atomic_read(&nr_comm_events
))
6517 comm_event
= (struct perf_comm_event
){
6523 .type
= PERF_RECORD_COMM
,
6524 .misc
= exec
? PERF_RECORD_MISC_COMM_EXEC
: 0,
6532 perf_event_comm_event(&comm_event
);
6539 struct perf_mmap_event
{
6540 struct vm_area_struct
*vma
;
6542 const char *file_name
;
6550 struct perf_event_header header
;
6560 static int perf_event_mmap_match(struct perf_event
*event
,
6563 struct perf_mmap_event
*mmap_event
= data
;
6564 struct vm_area_struct
*vma
= mmap_event
->vma
;
6565 int executable
= vma
->vm_flags
& VM_EXEC
;
6567 return (!executable
&& event
->attr
.mmap_data
) ||
6568 (executable
&& (event
->attr
.mmap
|| event
->attr
.mmap2
));
6571 static void perf_event_mmap_output(struct perf_event
*event
,
6574 struct perf_mmap_event
*mmap_event
= data
;
6575 struct perf_output_handle handle
;
6576 struct perf_sample_data sample
;
6577 int size
= mmap_event
->event_id
.header
.size
;
6580 if (!perf_event_mmap_match(event
, data
))
6583 if (event
->attr
.mmap2
) {
6584 mmap_event
->event_id
.header
.type
= PERF_RECORD_MMAP2
;
6585 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->maj
);
6586 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->min
);
6587 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->ino
);
6588 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->ino_generation
);
6589 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->prot
);
6590 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->flags
);
6593 perf_event_header__init_id(&mmap_event
->event_id
.header
, &sample
, event
);
6594 ret
= perf_output_begin(&handle
, event
,
6595 mmap_event
->event_id
.header
.size
);
6599 mmap_event
->event_id
.pid
= perf_event_pid(event
, current
);
6600 mmap_event
->event_id
.tid
= perf_event_tid(event
, current
);
6602 perf_output_put(&handle
, mmap_event
->event_id
);
6604 if (event
->attr
.mmap2
) {
6605 perf_output_put(&handle
, mmap_event
->maj
);
6606 perf_output_put(&handle
, mmap_event
->min
);
6607 perf_output_put(&handle
, mmap_event
->ino
);
6608 perf_output_put(&handle
, mmap_event
->ino_generation
);
6609 perf_output_put(&handle
, mmap_event
->prot
);
6610 perf_output_put(&handle
, mmap_event
->flags
);
6613 __output_copy(&handle
, mmap_event
->file_name
,
6614 mmap_event
->file_size
);
6616 perf_event__output_id_sample(event
, &handle
, &sample
);
6618 perf_output_end(&handle
);
6620 mmap_event
->event_id
.header
.size
= size
;
6623 static void perf_event_mmap_event(struct perf_mmap_event
*mmap_event
)
6625 struct vm_area_struct
*vma
= mmap_event
->vma
;
6626 struct file
*file
= vma
->vm_file
;
6627 int maj
= 0, min
= 0;
6628 u64 ino
= 0, gen
= 0;
6629 u32 prot
= 0, flags
= 0;
6635 if (vma
->vm_flags
& VM_READ
)
6637 if (vma
->vm_flags
& VM_WRITE
)
6639 if (vma
->vm_flags
& VM_EXEC
)
6642 if (vma
->vm_flags
& VM_MAYSHARE
)
6645 flags
= MAP_PRIVATE
;
6647 if (vma
->vm_flags
& VM_DENYWRITE
)
6648 flags
|= MAP_DENYWRITE
;
6649 if (vma
->vm_flags
& VM_MAYEXEC
)
6650 flags
|= MAP_EXECUTABLE
;
6651 if (vma
->vm_flags
& VM_LOCKED
)
6652 flags
|= MAP_LOCKED
;
6653 if (vma
->vm_flags
& VM_HUGETLB
)
6654 flags
|= MAP_HUGETLB
;
6657 struct inode
*inode
;
6660 buf
= kmalloc(PATH_MAX
, GFP_KERNEL
);
6666 * d_path() works from the end of the rb backwards, so we
6667 * need to add enough zero bytes after the string to handle
6668 * the 64bit alignment we do later.
6670 name
= file_path(file
, buf
, PATH_MAX
- sizeof(u64
));
6675 inode
= file_inode(vma
->vm_file
);
6676 dev
= inode
->i_sb
->s_dev
;
6678 gen
= inode
->i_generation
;
6684 if (vma
->vm_ops
&& vma
->vm_ops
->name
) {
6685 name
= (char *) vma
->vm_ops
->name(vma
);
6690 name
= (char *)arch_vma_name(vma
);
6694 if (vma
->vm_start
<= vma
->vm_mm
->start_brk
&&
6695 vma
->vm_end
>= vma
->vm_mm
->brk
) {
6699 if (vma
->vm_start
<= vma
->vm_mm
->start_stack
&&
6700 vma
->vm_end
>= vma
->vm_mm
->start_stack
) {
6710 strlcpy(tmp
, name
, sizeof(tmp
));
6714 * Since our buffer works in 8 byte units we need to align our string
6715 * size to a multiple of 8. However, we must guarantee the tail end is
6716 * zero'd out to avoid leaking random bits to userspace.
6718 size
= strlen(name
)+1;
6719 while (!IS_ALIGNED(size
, sizeof(u64
)))
6720 name
[size
++] = '\0';
6722 mmap_event
->file_name
= name
;
6723 mmap_event
->file_size
= size
;
6724 mmap_event
->maj
= maj
;
6725 mmap_event
->min
= min
;
6726 mmap_event
->ino
= ino
;
6727 mmap_event
->ino_generation
= gen
;
6728 mmap_event
->prot
= prot
;
6729 mmap_event
->flags
= flags
;
6731 if (!(vma
->vm_flags
& VM_EXEC
))
6732 mmap_event
->event_id
.header
.misc
|= PERF_RECORD_MISC_MMAP_DATA
;
6734 mmap_event
->event_id
.header
.size
= sizeof(mmap_event
->event_id
) + size
;
6736 perf_iterate_sb(perf_event_mmap_output
,
6744 * Check whether inode and address range match filter criteria.
6746 static bool perf_addr_filter_match(struct perf_addr_filter
*filter
,
6747 struct file
*file
, unsigned long offset
,
6750 if (filter
->inode
!= file_inode(file
))
6753 if (filter
->offset
> offset
+ size
)
6756 if (filter
->offset
+ filter
->size
< offset
)
6762 static void __perf_addr_filters_adjust(struct perf_event
*event
, void *data
)
6764 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
6765 struct vm_area_struct
*vma
= data
;
6766 unsigned long off
= vma
->vm_pgoff
<< PAGE_SHIFT
, flags
;
6767 struct file
*file
= vma
->vm_file
;
6768 struct perf_addr_filter
*filter
;
6769 unsigned int restart
= 0, count
= 0;
6771 if (!has_addr_filter(event
))
6777 raw_spin_lock_irqsave(&ifh
->lock
, flags
);
6778 list_for_each_entry(filter
, &ifh
->list
, entry
) {
6779 if (perf_addr_filter_match(filter
, file
, off
,
6780 vma
->vm_end
- vma
->vm_start
)) {
6781 event
->addr_filters_offs
[count
] = vma
->vm_start
;
6789 event
->addr_filters_gen
++;
6790 raw_spin_unlock_irqrestore(&ifh
->lock
, flags
);
6793 perf_event_stop(event
, 1);
6797 * Adjust all task's events' filters to the new vma
6799 static void perf_addr_filters_adjust(struct vm_area_struct
*vma
)
6801 struct perf_event_context
*ctx
;
6805 * Data tracing isn't supported yet and as such there is no need
6806 * to keep track of anything that isn't related to executable code:
6808 if (!(vma
->vm_flags
& VM_EXEC
))
6812 for_each_task_context_nr(ctxn
) {
6813 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
6817 perf_iterate_ctx(ctx
, __perf_addr_filters_adjust
, vma
, true);
6822 void perf_event_mmap(struct vm_area_struct
*vma
)
6824 struct perf_mmap_event mmap_event
;
6826 if (!atomic_read(&nr_mmap_events
))
6829 mmap_event
= (struct perf_mmap_event
){
6835 .type
= PERF_RECORD_MMAP
,
6836 .misc
= PERF_RECORD_MISC_USER
,
6841 .start
= vma
->vm_start
,
6842 .len
= vma
->vm_end
- vma
->vm_start
,
6843 .pgoff
= (u64
)vma
->vm_pgoff
<< PAGE_SHIFT
,
6845 /* .maj (attr_mmap2 only) */
6846 /* .min (attr_mmap2 only) */
6847 /* .ino (attr_mmap2 only) */
6848 /* .ino_generation (attr_mmap2 only) */
6849 /* .prot (attr_mmap2 only) */
6850 /* .flags (attr_mmap2 only) */
6853 perf_addr_filters_adjust(vma
);
6854 perf_event_mmap_event(&mmap_event
);
6857 void perf_event_aux_event(struct perf_event
*event
, unsigned long head
,
6858 unsigned long size
, u64 flags
)
6860 struct perf_output_handle handle
;
6861 struct perf_sample_data sample
;
6862 struct perf_aux_event
{
6863 struct perf_event_header header
;
6869 .type
= PERF_RECORD_AUX
,
6871 .size
= sizeof(rec
),
6879 perf_event_header__init_id(&rec
.header
, &sample
, event
);
6880 ret
= perf_output_begin(&handle
, event
, rec
.header
.size
);
6885 perf_output_put(&handle
, rec
);
6886 perf_event__output_id_sample(event
, &handle
, &sample
);
6888 perf_output_end(&handle
);
6892 * Lost/dropped samples logging
6894 void perf_log_lost_samples(struct perf_event
*event
, u64 lost
)
6896 struct perf_output_handle handle
;
6897 struct perf_sample_data sample
;
6901 struct perf_event_header header
;
6903 } lost_samples_event
= {
6905 .type
= PERF_RECORD_LOST_SAMPLES
,
6907 .size
= sizeof(lost_samples_event
),
6912 perf_event_header__init_id(&lost_samples_event
.header
, &sample
, event
);
6914 ret
= perf_output_begin(&handle
, event
,
6915 lost_samples_event
.header
.size
);
6919 perf_output_put(&handle
, lost_samples_event
);
6920 perf_event__output_id_sample(event
, &handle
, &sample
);
6921 perf_output_end(&handle
);
6925 * context_switch tracking
6928 struct perf_switch_event
{
6929 struct task_struct
*task
;
6930 struct task_struct
*next_prev
;
6933 struct perf_event_header header
;
6939 static int perf_event_switch_match(struct perf_event
*event
)
6941 return event
->attr
.context_switch
;
6944 static void perf_event_switch_output(struct perf_event
*event
, void *data
)
6946 struct perf_switch_event
*se
= data
;
6947 struct perf_output_handle handle
;
6948 struct perf_sample_data sample
;
6951 if (!perf_event_switch_match(event
))
6954 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6955 if (event
->ctx
->task
) {
6956 se
->event_id
.header
.type
= PERF_RECORD_SWITCH
;
6957 se
->event_id
.header
.size
= sizeof(se
->event_id
.header
);
6959 se
->event_id
.header
.type
= PERF_RECORD_SWITCH_CPU_WIDE
;
6960 se
->event_id
.header
.size
= sizeof(se
->event_id
);
6961 se
->event_id
.next_prev_pid
=
6962 perf_event_pid(event
, se
->next_prev
);
6963 se
->event_id
.next_prev_tid
=
6964 perf_event_tid(event
, se
->next_prev
);
6967 perf_event_header__init_id(&se
->event_id
.header
, &sample
, event
);
6969 ret
= perf_output_begin(&handle
, event
, se
->event_id
.header
.size
);
6973 if (event
->ctx
->task
)
6974 perf_output_put(&handle
, se
->event_id
.header
);
6976 perf_output_put(&handle
, se
->event_id
);
6978 perf_event__output_id_sample(event
, &handle
, &sample
);
6980 perf_output_end(&handle
);
6983 static void perf_event_switch(struct task_struct
*task
,
6984 struct task_struct
*next_prev
, bool sched_in
)
6986 struct perf_switch_event switch_event
;
6988 /* N.B. caller checks nr_switch_events != 0 */
6990 switch_event
= (struct perf_switch_event
){
6992 .next_prev
= next_prev
,
6996 .misc
= sched_in
? 0 : PERF_RECORD_MISC_SWITCH_OUT
,
6999 /* .next_prev_pid */
7000 /* .next_prev_tid */
7004 perf_iterate_sb(perf_event_switch_output
,
7010 * IRQ throttle logging
7013 static void perf_log_throttle(struct perf_event
*event
, int enable
)
7015 struct perf_output_handle handle
;
7016 struct perf_sample_data sample
;
7020 struct perf_event_header header
;
7024 } throttle_event
= {
7026 .type
= PERF_RECORD_THROTTLE
,
7028 .size
= sizeof(throttle_event
),
7030 .time
= perf_event_clock(event
),
7031 .id
= primary_event_id(event
),
7032 .stream_id
= event
->id
,
7036 throttle_event
.header
.type
= PERF_RECORD_UNTHROTTLE
;
7038 perf_event_header__init_id(&throttle_event
.header
, &sample
, event
);
7040 ret
= perf_output_begin(&handle
, event
,
7041 throttle_event
.header
.size
);
7045 perf_output_put(&handle
, throttle_event
);
7046 perf_event__output_id_sample(event
, &handle
, &sample
);
7047 perf_output_end(&handle
);
7050 static void perf_log_itrace_start(struct perf_event
*event
)
7052 struct perf_output_handle handle
;
7053 struct perf_sample_data sample
;
7054 struct perf_aux_event
{
7055 struct perf_event_header header
;
7062 event
= event
->parent
;
7064 if (!(event
->pmu
->capabilities
& PERF_PMU_CAP_ITRACE
) ||
7065 event
->hw
.itrace_started
)
7068 rec
.header
.type
= PERF_RECORD_ITRACE_START
;
7069 rec
.header
.misc
= 0;
7070 rec
.header
.size
= sizeof(rec
);
7071 rec
.pid
= perf_event_pid(event
, current
);
7072 rec
.tid
= perf_event_tid(event
, current
);
7074 perf_event_header__init_id(&rec
.header
, &sample
, event
);
7075 ret
= perf_output_begin(&handle
, event
, rec
.header
.size
);
7080 perf_output_put(&handle
, rec
);
7081 perf_event__output_id_sample(event
, &handle
, &sample
);
7083 perf_output_end(&handle
);
7087 __perf_event_account_interrupt(struct perf_event
*event
, int throttle
)
7089 struct hw_perf_event
*hwc
= &event
->hw
;
7093 seq
= __this_cpu_read(perf_throttled_seq
);
7094 if (seq
!= hwc
->interrupts_seq
) {
7095 hwc
->interrupts_seq
= seq
;
7096 hwc
->interrupts
= 1;
7099 if (unlikely(throttle
7100 && hwc
->interrupts
>= max_samples_per_tick
)) {
7101 __this_cpu_inc(perf_throttled_count
);
7102 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS
);
7103 hwc
->interrupts
= MAX_INTERRUPTS
;
7104 perf_log_throttle(event
, 0);
7109 if (event
->attr
.freq
) {
7110 u64 now
= perf_clock();
7111 s64 delta
= now
- hwc
->freq_time_stamp
;
7113 hwc
->freq_time_stamp
= now
;
7115 if (delta
> 0 && delta
< 2*TICK_NSEC
)
7116 perf_adjust_period(event
, delta
, hwc
->last_period
, true);
7122 int perf_event_account_interrupt(struct perf_event
*event
)
7124 return __perf_event_account_interrupt(event
, 1);
7128 * Generic event overflow handling, sampling.
7131 static int __perf_event_overflow(struct perf_event
*event
,
7132 int throttle
, struct perf_sample_data
*data
,
7133 struct pt_regs
*regs
)
7135 int events
= atomic_read(&event
->event_limit
);
7139 * Non-sampling counters might still use the PMI to fold short
7140 * hardware counters, ignore those.
7142 if (unlikely(!is_sampling_event(event
)))
7145 ret
= __perf_event_account_interrupt(event
, throttle
);
7148 * XXX event_limit might not quite work as expected on inherited
7152 event
->pending_kill
= POLL_IN
;
7153 if (events
&& atomic_dec_and_test(&event
->event_limit
)) {
7155 event
->pending_kill
= POLL_HUP
;
7157 perf_event_disable_inatomic(event
);
7160 READ_ONCE(event
->overflow_handler
)(event
, data
, regs
);
7162 if (*perf_event_fasync(event
) && event
->pending_kill
) {
7163 event
->pending_wakeup
= 1;
7164 irq_work_queue(&event
->pending
);
7170 int perf_event_overflow(struct perf_event
*event
,
7171 struct perf_sample_data
*data
,
7172 struct pt_regs
*regs
)
7174 return __perf_event_overflow(event
, 1, data
, regs
);
7178 * Generic software event infrastructure
7181 struct swevent_htable
{
7182 struct swevent_hlist
*swevent_hlist
;
7183 struct mutex hlist_mutex
;
7186 /* Recursion avoidance in each contexts */
7187 int recursion
[PERF_NR_CONTEXTS
];
7190 static DEFINE_PER_CPU(struct swevent_htable
, swevent_htable
);
7193 * We directly increment event->count and keep a second value in
7194 * event->hw.period_left to count intervals. This period event
7195 * is kept in the range [-sample_period, 0] so that we can use the
7199 u64
perf_swevent_set_period(struct perf_event
*event
)
7201 struct hw_perf_event
*hwc
= &event
->hw
;
7202 u64 period
= hwc
->last_period
;
7206 hwc
->last_period
= hwc
->sample_period
;
7209 old
= val
= local64_read(&hwc
->period_left
);
7213 nr
= div64_u64(period
+ val
, period
);
7214 offset
= nr
* period
;
7216 if (local64_cmpxchg(&hwc
->period_left
, old
, val
) != old
)
7222 static void perf_swevent_overflow(struct perf_event
*event
, u64 overflow
,
7223 struct perf_sample_data
*data
,
7224 struct pt_regs
*regs
)
7226 struct hw_perf_event
*hwc
= &event
->hw
;
7230 overflow
= perf_swevent_set_period(event
);
7232 if (hwc
->interrupts
== MAX_INTERRUPTS
)
7235 for (; overflow
; overflow
--) {
7236 if (__perf_event_overflow(event
, throttle
,
7239 * We inhibit the overflow from happening when
7240 * hwc->interrupts == MAX_INTERRUPTS.
7248 static void perf_swevent_event(struct perf_event
*event
, u64 nr
,
7249 struct perf_sample_data
*data
,
7250 struct pt_regs
*regs
)
7252 struct hw_perf_event
*hwc
= &event
->hw
;
7254 local64_add(nr
, &event
->count
);
7259 if (!is_sampling_event(event
))
7262 if ((event
->attr
.sample_type
& PERF_SAMPLE_PERIOD
) && !event
->attr
.freq
) {
7264 return perf_swevent_overflow(event
, 1, data
, regs
);
7266 data
->period
= event
->hw
.last_period
;
7268 if (nr
== 1 && hwc
->sample_period
== 1 && !event
->attr
.freq
)
7269 return perf_swevent_overflow(event
, 1, data
, regs
);
7271 if (local64_add_negative(nr
, &hwc
->period_left
))
7274 perf_swevent_overflow(event
, 0, data
, regs
);
7277 static int perf_exclude_event(struct perf_event
*event
,
7278 struct pt_regs
*regs
)
7280 if (event
->hw
.state
& PERF_HES_STOPPED
)
7284 if (event
->attr
.exclude_user
&& user_mode(regs
))
7287 if (event
->attr
.exclude_kernel
&& !user_mode(regs
))
7294 static int perf_swevent_match(struct perf_event
*event
,
7295 enum perf_type_id type
,
7297 struct perf_sample_data
*data
,
7298 struct pt_regs
*regs
)
7300 if (event
->attr
.type
!= type
)
7303 if (event
->attr
.config
!= event_id
)
7306 if (perf_exclude_event(event
, regs
))
7312 static inline u64
swevent_hash(u64 type
, u32 event_id
)
7314 u64 val
= event_id
| (type
<< 32);
7316 return hash_64(val
, SWEVENT_HLIST_BITS
);
7319 static inline struct hlist_head
*
7320 __find_swevent_head(struct swevent_hlist
*hlist
, u64 type
, u32 event_id
)
7322 u64 hash
= swevent_hash(type
, event_id
);
7324 return &hlist
->heads
[hash
];
7327 /* For the read side: events when they trigger */
7328 static inline struct hlist_head
*
7329 find_swevent_head_rcu(struct swevent_htable
*swhash
, u64 type
, u32 event_id
)
7331 struct swevent_hlist
*hlist
;
7333 hlist
= rcu_dereference(swhash
->swevent_hlist
);
7337 return __find_swevent_head(hlist
, type
, event_id
);
7340 /* For the event head insertion and removal in the hlist */
7341 static inline struct hlist_head
*
7342 find_swevent_head(struct swevent_htable
*swhash
, struct perf_event
*event
)
7344 struct swevent_hlist
*hlist
;
7345 u32 event_id
= event
->attr
.config
;
7346 u64 type
= event
->attr
.type
;
7349 * Event scheduling is always serialized against hlist allocation
7350 * and release. Which makes the protected version suitable here.
7351 * The context lock guarantees that.
7353 hlist
= rcu_dereference_protected(swhash
->swevent_hlist
,
7354 lockdep_is_held(&event
->ctx
->lock
));
7358 return __find_swevent_head(hlist
, type
, event_id
);
7361 static void do_perf_sw_event(enum perf_type_id type
, u32 event_id
,
7363 struct perf_sample_data
*data
,
7364 struct pt_regs
*regs
)
7366 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7367 struct perf_event
*event
;
7368 struct hlist_head
*head
;
7371 head
= find_swevent_head_rcu(swhash
, type
, event_id
);
7375 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
7376 if (perf_swevent_match(event
, type
, event_id
, data
, regs
))
7377 perf_swevent_event(event
, nr
, data
, regs
);
7383 DEFINE_PER_CPU(struct pt_regs
, __perf_regs
[4]);
7385 int perf_swevent_get_recursion_context(void)
7387 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7389 return get_recursion_context(swhash
->recursion
);
7391 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context
);
7393 void perf_swevent_put_recursion_context(int rctx
)
7395 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7397 put_recursion_context(swhash
->recursion
, rctx
);
7400 void ___perf_sw_event(u32 event_id
, u64 nr
, struct pt_regs
*regs
, u64 addr
)
7402 struct perf_sample_data data
;
7404 if (WARN_ON_ONCE(!regs
))
7407 perf_sample_data_init(&data
, addr
, 0);
7408 do_perf_sw_event(PERF_TYPE_SOFTWARE
, event_id
, nr
, &data
, regs
);
7411 void __perf_sw_event(u32 event_id
, u64 nr
, struct pt_regs
*regs
, u64 addr
)
7415 preempt_disable_notrace();
7416 rctx
= perf_swevent_get_recursion_context();
7417 if (unlikely(rctx
< 0))
7420 ___perf_sw_event(event_id
, nr
, regs
, addr
);
7422 perf_swevent_put_recursion_context(rctx
);
7424 preempt_enable_notrace();
7427 static void perf_swevent_read(struct perf_event
*event
)
7431 static int perf_swevent_add(struct perf_event
*event
, int flags
)
7433 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7434 struct hw_perf_event
*hwc
= &event
->hw
;
7435 struct hlist_head
*head
;
7437 if (is_sampling_event(event
)) {
7438 hwc
->last_period
= hwc
->sample_period
;
7439 perf_swevent_set_period(event
);
7442 hwc
->state
= !(flags
& PERF_EF_START
);
7444 head
= find_swevent_head(swhash
, event
);
7445 if (WARN_ON_ONCE(!head
))
7448 hlist_add_head_rcu(&event
->hlist_entry
, head
);
7449 perf_event_update_userpage(event
);
7454 static void perf_swevent_del(struct perf_event
*event
, int flags
)
7456 hlist_del_rcu(&event
->hlist_entry
);
7459 static void perf_swevent_start(struct perf_event
*event
, int flags
)
7461 event
->hw
.state
= 0;
7464 static void perf_swevent_stop(struct perf_event
*event
, int flags
)
7466 event
->hw
.state
= PERF_HES_STOPPED
;
7469 /* Deref the hlist from the update side */
7470 static inline struct swevent_hlist
*
7471 swevent_hlist_deref(struct swevent_htable
*swhash
)
7473 return rcu_dereference_protected(swhash
->swevent_hlist
,
7474 lockdep_is_held(&swhash
->hlist_mutex
));
7477 static void swevent_hlist_release(struct swevent_htable
*swhash
)
7479 struct swevent_hlist
*hlist
= swevent_hlist_deref(swhash
);
7484 RCU_INIT_POINTER(swhash
->swevent_hlist
, NULL
);
7485 kfree_rcu(hlist
, rcu_head
);
7488 static void swevent_hlist_put_cpu(int cpu
)
7490 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
7492 mutex_lock(&swhash
->hlist_mutex
);
7494 if (!--swhash
->hlist_refcount
)
7495 swevent_hlist_release(swhash
);
7497 mutex_unlock(&swhash
->hlist_mutex
);
7500 static void swevent_hlist_put(void)
7504 for_each_possible_cpu(cpu
)
7505 swevent_hlist_put_cpu(cpu
);
7508 static int swevent_hlist_get_cpu(int cpu
)
7510 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
7513 mutex_lock(&swhash
->hlist_mutex
);
7514 if (!swevent_hlist_deref(swhash
) && cpu_online(cpu
)) {
7515 struct swevent_hlist
*hlist
;
7517 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
7522 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
7524 swhash
->hlist_refcount
++;
7526 mutex_unlock(&swhash
->hlist_mutex
);
7531 static int swevent_hlist_get(void)
7533 int err
, cpu
, failed_cpu
;
7536 for_each_possible_cpu(cpu
) {
7537 err
= swevent_hlist_get_cpu(cpu
);
7547 for_each_possible_cpu(cpu
) {
7548 if (cpu
== failed_cpu
)
7550 swevent_hlist_put_cpu(cpu
);
7557 struct static_key perf_swevent_enabled
[PERF_COUNT_SW_MAX
];
7559 static void sw_perf_event_destroy(struct perf_event
*event
)
7561 u64 event_id
= event
->attr
.config
;
7563 WARN_ON(event
->parent
);
7565 static_key_slow_dec(&perf_swevent_enabled
[event_id
]);
7566 swevent_hlist_put();
7569 static int perf_swevent_init(struct perf_event
*event
)
7571 u64 event_id
= event
->attr
.config
;
7573 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
7577 * no branch sampling for software events
7579 if (has_branch_stack(event
))
7583 case PERF_COUNT_SW_CPU_CLOCK
:
7584 case PERF_COUNT_SW_TASK_CLOCK
:
7591 if (event_id
>= PERF_COUNT_SW_MAX
)
7594 if (!event
->parent
) {
7597 err
= swevent_hlist_get();
7601 static_key_slow_inc(&perf_swevent_enabled
[event_id
]);
7602 event
->destroy
= sw_perf_event_destroy
;
7608 static struct pmu perf_swevent
= {
7609 .task_ctx_nr
= perf_sw_context
,
7611 .capabilities
= PERF_PMU_CAP_NO_NMI
,
7613 .event_init
= perf_swevent_init
,
7614 .add
= perf_swevent_add
,
7615 .del
= perf_swevent_del
,
7616 .start
= perf_swevent_start
,
7617 .stop
= perf_swevent_stop
,
7618 .read
= perf_swevent_read
,
7621 #ifdef CONFIG_EVENT_TRACING
7623 static int perf_tp_filter_match(struct perf_event
*event
,
7624 struct perf_sample_data
*data
)
7626 void *record
= data
->raw
->frag
.data
;
7628 /* only top level events have filters set */
7630 event
= event
->parent
;
7632 if (likely(!event
->filter
) || filter_match_preds(event
->filter
, record
))
7637 static int perf_tp_event_match(struct perf_event
*event
,
7638 struct perf_sample_data
*data
,
7639 struct pt_regs
*regs
)
7641 if (event
->hw
.state
& PERF_HES_STOPPED
)
7644 * All tracepoints are from kernel-space.
7646 if (event
->attr
.exclude_kernel
)
7649 if (!perf_tp_filter_match(event
, data
))
7655 void perf_trace_run_bpf_submit(void *raw_data
, int size
, int rctx
,
7656 struct trace_event_call
*call
, u64 count
,
7657 struct pt_regs
*regs
, struct hlist_head
*head
,
7658 struct task_struct
*task
)
7660 struct bpf_prog
*prog
= call
->prog
;
7663 *(struct pt_regs
**)raw_data
= regs
;
7664 if (!trace_call_bpf(prog
, raw_data
) || hlist_empty(head
)) {
7665 perf_swevent_put_recursion_context(rctx
);
7669 perf_tp_event(call
->event
.type
, count
, raw_data
, size
, regs
, head
,
7672 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit
);
7674 void perf_tp_event(u16 event_type
, u64 count
, void *record
, int entry_size
,
7675 struct pt_regs
*regs
, struct hlist_head
*head
, int rctx
,
7676 struct task_struct
*task
)
7678 struct perf_sample_data data
;
7679 struct perf_event
*event
;
7681 struct perf_raw_record raw
= {
7688 perf_sample_data_init(&data
, 0, 0);
7691 perf_trace_buf_update(record
, event_type
);
7693 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
7694 if (perf_tp_event_match(event
, &data
, regs
))
7695 perf_swevent_event(event
, count
, &data
, regs
);
7699 * If we got specified a target task, also iterate its context and
7700 * deliver this event there too.
7702 if (task
&& task
!= current
) {
7703 struct perf_event_context
*ctx
;
7704 struct trace_entry
*entry
= record
;
7707 ctx
= rcu_dereference(task
->perf_event_ctxp
[perf_sw_context
]);
7711 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
7712 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
7714 if (event
->attr
.config
!= entry
->type
)
7716 if (perf_tp_event_match(event
, &data
, regs
))
7717 perf_swevent_event(event
, count
, &data
, regs
);
7723 perf_swevent_put_recursion_context(rctx
);
7725 EXPORT_SYMBOL_GPL(perf_tp_event
);
7727 static void tp_perf_event_destroy(struct perf_event
*event
)
7729 perf_trace_destroy(event
);
7732 static int perf_tp_event_init(struct perf_event
*event
)
7736 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
7740 * no branch sampling for tracepoint events
7742 if (has_branch_stack(event
))
7745 err
= perf_trace_init(event
);
7749 event
->destroy
= tp_perf_event_destroy
;
7754 static struct pmu perf_tracepoint
= {
7755 .task_ctx_nr
= perf_sw_context
,
7757 .event_init
= perf_tp_event_init
,
7758 .add
= perf_trace_add
,
7759 .del
= perf_trace_del
,
7760 .start
= perf_swevent_start
,
7761 .stop
= perf_swevent_stop
,
7762 .read
= perf_swevent_read
,
7765 static inline void perf_tp_register(void)
7767 perf_pmu_register(&perf_tracepoint
, "tracepoint", PERF_TYPE_TRACEPOINT
);
7770 static void perf_event_free_filter(struct perf_event
*event
)
7772 ftrace_profile_free_filter(event
);
7775 #ifdef CONFIG_BPF_SYSCALL
7776 static void bpf_overflow_handler(struct perf_event
*event
,
7777 struct perf_sample_data
*data
,
7778 struct pt_regs
*regs
)
7780 struct bpf_perf_event_data_kern ctx
= {
7787 if (unlikely(__this_cpu_inc_return(bpf_prog_active
) != 1))
7790 ret
= BPF_PROG_RUN(event
->prog
, &ctx
);
7793 __this_cpu_dec(bpf_prog_active
);
7798 event
->orig_overflow_handler(event
, data
, regs
);
7801 static int perf_event_set_bpf_handler(struct perf_event
*event
, u32 prog_fd
)
7803 struct bpf_prog
*prog
;
7805 if (event
->overflow_handler_context
)
7806 /* hw breakpoint or kernel counter */
7812 prog
= bpf_prog_get_type(prog_fd
, BPF_PROG_TYPE_PERF_EVENT
);
7814 return PTR_ERR(prog
);
7817 event
->orig_overflow_handler
= READ_ONCE(event
->overflow_handler
);
7818 WRITE_ONCE(event
->overflow_handler
, bpf_overflow_handler
);
7822 static void perf_event_free_bpf_handler(struct perf_event
*event
)
7824 struct bpf_prog
*prog
= event
->prog
;
7829 WRITE_ONCE(event
->overflow_handler
, event
->orig_overflow_handler
);
7834 static int perf_event_set_bpf_handler(struct perf_event
*event
, u32 prog_fd
)
7838 static void perf_event_free_bpf_handler(struct perf_event
*event
)
7843 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
)
7845 bool is_kprobe
, is_tracepoint
;
7846 struct bpf_prog
*prog
;
7848 if (event
->attr
.type
== PERF_TYPE_HARDWARE
||
7849 event
->attr
.type
== PERF_TYPE_SOFTWARE
)
7850 return perf_event_set_bpf_handler(event
, prog_fd
);
7852 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
7855 if (event
->tp_event
->prog
)
7858 is_kprobe
= event
->tp_event
->flags
& TRACE_EVENT_FL_UKPROBE
;
7859 is_tracepoint
= event
->tp_event
->flags
& TRACE_EVENT_FL_TRACEPOINT
;
7860 if (!is_kprobe
&& !is_tracepoint
)
7861 /* bpf programs can only be attached to u/kprobe or tracepoint */
7864 prog
= bpf_prog_get(prog_fd
);
7866 return PTR_ERR(prog
);
7868 if ((is_kprobe
&& prog
->type
!= BPF_PROG_TYPE_KPROBE
) ||
7869 (is_tracepoint
&& prog
->type
!= BPF_PROG_TYPE_TRACEPOINT
)) {
7870 /* valid fd, but invalid bpf program type */
7875 if (is_tracepoint
) {
7876 int off
= trace_event_get_offsets(event
->tp_event
);
7878 if (prog
->aux
->max_ctx_offset
> off
) {
7883 event
->tp_event
->prog
= prog
;
7888 static void perf_event_free_bpf_prog(struct perf_event
*event
)
7890 struct bpf_prog
*prog
;
7892 perf_event_free_bpf_handler(event
);
7894 if (!event
->tp_event
)
7897 prog
= event
->tp_event
->prog
;
7899 event
->tp_event
->prog
= NULL
;
7906 static inline void perf_tp_register(void)
7910 static void perf_event_free_filter(struct perf_event
*event
)
7914 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
)
7919 static void perf_event_free_bpf_prog(struct perf_event
*event
)
7922 #endif /* CONFIG_EVENT_TRACING */
7924 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7925 void perf_bp_event(struct perf_event
*bp
, void *data
)
7927 struct perf_sample_data sample
;
7928 struct pt_regs
*regs
= data
;
7930 perf_sample_data_init(&sample
, bp
->attr
.bp_addr
, 0);
7932 if (!bp
->hw
.state
&& !perf_exclude_event(bp
, regs
))
7933 perf_swevent_event(bp
, 1, &sample
, regs
);
7938 * Allocate a new address filter
7940 static struct perf_addr_filter
*
7941 perf_addr_filter_new(struct perf_event
*event
, struct list_head
*filters
)
7943 int node
= cpu_to_node(event
->cpu
== -1 ? 0 : event
->cpu
);
7944 struct perf_addr_filter
*filter
;
7946 filter
= kzalloc_node(sizeof(*filter
), GFP_KERNEL
, node
);
7950 INIT_LIST_HEAD(&filter
->entry
);
7951 list_add_tail(&filter
->entry
, filters
);
7956 static void free_filters_list(struct list_head
*filters
)
7958 struct perf_addr_filter
*filter
, *iter
;
7960 list_for_each_entry_safe(filter
, iter
, filters
, entry
) {
7962 iput(filter
->inode
);
7963 list_del(&filter
->entry
);
7969 * Free existing address filters and optionally install new ones
7971 static void perf_addr_filters_splice(struct perf_event
*event
,
7972 struct list_head
*head
)
7974 unsigned long flags
;
7977 if (!has_addr_filter(event
))
7980 /* don't bother with children, they don't have their own filters */
7984 raw_spin_lock_irqsave(&event
->addr_filters
.lock
, flags
);
7986 list_splice_init(&event
->addr_filters
.list
, &list
);
7988 list_splice(head
, &event
->addr_filters
.list
);
7990 raw_spin_unlock_irqrestore(&event
->addr_filters
.lock
, flags
);
7992 free_filters_list(&list
);
7996 * Scan through mm's vmas and see if one of them matches the
7997 * @filter; if so, adjust filter's address range.
7998 * Called with mm::mmap_sem down for reading.
8000 static unsigned long perf_addr_filter_apply(struct perf_addr_filter
*filter
,
8001 struct mm_struct
*mm
)
8003 struct vm_area_struct
*vma
;
8005 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
8006 struct file
*file
= vma
->vm_file
;
8007 unsigned long off
= vma
->vm_pgoff
<< PAGE_SHIFT
;
8008 unsigned long vma_size
= vma
->vm_end
- vma
->vm_start
;
8013 if (!perf_addr_filter_match(filter
, file
, off
, vma_size
))
8016 return vma
->vm_start
;
8023 * Update event's address range filters based on the
8024 * task's existing mappings, if any.
8026 static void perf_event_addr_filters_apply(struct perf_event
*event
)
8028 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
8029 struct task_struct
*task
= READ_ONCE(event
->ctx
->task
);
8030 struct perf_addr_filter
*filter
;
8031 struct mm_struct
*mm
= NULL
;
8032 unsigned int count
= 0;
8033 unsigned long flags
;
8036 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8037 * will stop on the parent's child_mutex that our caller is also holding
8039 if (task
== TASK_TOMBSTONE
)
8042 mm
= get_task_mm(event
->ctx
->task
);
8046 down_read(&mm
->mmap_sem
);
8048 raw_spin_lock_irqsave(&ifh
->lock
, flags
);
8049 list_for_each_entry(filter
, &ifh
->list
, entry
) {
8050 event
->addr_filters_offs
[count
] = 0;
8053 * Adjust base offset if the filter is associated to a binary
8054 * that needs to be mapped:
8057 event
->addr_filters_offs
[count
] =
8058 perf_addr_filter_apply(filter
, mm
);
8063 event
->addr_filters_gen
++;
8064 raw_spin_unlock_irqrestore(&ifh
->lock
, flags
);
8066 up_read(&mm
->mmap_sem
);
8071 perf_event_stop(event
, 1);
8075 * Address range filtering: limiting the data to certain
8076 * instruction address ranges. Filters are ioctl()ed to us from
8077 * userspace as ascii strings.
8079 * Filter string format:
8082 * where ACTION is one of the
8083 * * "filter": limit the trace to this region
8084 * * "start": start tracing from this address
8085 * * "stop": stop tracing at this address/region;
8087 * * for kernel addresses: <start address>[/<size>]
8088 * * for object files: <start address>[/<size>]@</path/to/object/file>
8090 * if <size> is not specified, the range is treated as a single address.
8104 IF_STATE_ACTION
= 0,
8109 static const match_table_t if_tokens
= {
8110 { IF_ACT_FILTER
, "filter" },
8111 { IF_ACT_START
, "start" },
8112 { IF_ACT_STOP
, "stop" },
8113 { IF_SRC_FILE
, "%u/%u@%s" },
8114 { IF_SRC_KERNEL
, "%u/%u" },
8115 { IF_SRC_FILEADDR
, "%u@%s" },
8116 { IF_SRC_KERNELADDR
, "%u" },
8117 { IF_ACT_NONE
, NULL
},
8121 * Address filter string parser
8124 perf_event_parse_addr_filter(struct perf_event
*event
, char *fstr
,
8125 struct list_head
*filters
)
8127 struct perf_addr_filter
*filter
= NULL
;
8128 char *start
, *orig
, *filename
= NULL
;
8130 substring_t args
[MAX_OPT_ARGS
];
8131 int state
= IF_STATE_ACTION
, token
;
8132 unsigned int kernel
= 0;
8135 orig
= fstr
= kstrdup(fstr
, GFP_KERNEL
);
8139 while ((start
= strsep(&fstr
, " ,\n")) != NULL
) {
8145 /* filter definition begins */
8146 if (state
== IF_STATE_ACTION
) {
8147 filter
= perf_addr_filter_new(event
, filters
);
8152 token
= match_token(start
, if_tokens
, args
);
8159 if (state
!= IF_STATE_ACTION
)
8162 state
= IF_STATE_SOURCE
;
8165 case IF_SRC_KERNELADDR
:
8169 case IF_SRC_FILEADDR
:
8171 if (state
!= IF_STATE_SOURCE
)
8174 if (token
== IF_SRC_FILE
|| token
== IF_SRC_KERNEL
)
8178 ret
= kstrtoul(args
[0].from
, 0, &filter
->offset
);
8182 if (filter
->range
) {
8184 ret
= kstrtoul(args
[1].from
, 0, &filter
->size
);
8189 if (token
== IF_SRC_FILE
|| token
== IF_SRC_FILEADDR
) {
8190 int fpos
= filter
->range
? 2 : 1;
8192 filename
= match_strdup(&args
[fpos
]);
8199 state
= IF_STATE_END
;
8207 * Filter definition is fully parsed, validate and install it.
8208 * Make sure that it doesn't contradict itself or the event's
8211 if (state
== IF_STATE_END
) {
8212 if (kernel
&& event
->attr
.exclude_kernel
)
8219 /* look up the path and grab its inode */
8220 ret
= kern_path(filename
, LOOKUP_FOLLOW
, &path
);
8222 goto fail_free_name
;
8224 filter
->inode
= igrab(d_inode(path
.dentry
));
8230 if (!filter
->inode
||
8231 !S_ISREG(filter
->inode
->i_mode
))
8232 /* free_filters_list() will iput() */
8236 /* ready to consume more filters */
8237 state
= IF_STATE_ACTION
;
8242 if (state
!= IF_STATE_ACTION
)
8252 free_filters_list(filters
);
8259 perf_event_set_addr_filter(struct perf_event
*event
, char *filter_str
)
8265 * Since this is called in perf_ioctl() path, we're already holding
8268 lockdep_assert_held(&event
->ctx
->mutex
);
8270 if (WARN_ON_ONCE(event
->parent
))
8274 * For now, we only support filtering in per-task events; doing so
8275 * for CPU-wide events requires additional context switching trickery,
8276 * since same object code will be mapped at different virtual
8277 * addresses in different processes.
8279 if (!event
->ctx
->task
)
8282 ret
= perf_event_parse_addr_filter(event
, filter_str
, &filters
);
8286 ret
= event
->pmu
->addr_filters_validate(&filters
);
8288 free_filters_list(&filters
);
8292 /* remove existing filters, if any */
8293 perf_addr_filters_splice(event
, &filters
);
8295 /* install new filters */
8296 perf_event_for_each_child(event
, perf_event_addr_filters_apply
);
8301 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
8306 if ((event
->attr
.type
!= PERF_TYPE_TRACEPOINT
||
8307 !IS_ENABLED(CONFIG_EVENT_TRACING
)) &&
8308 !has_addr_filter(event
))
8311 filter_str
= strndup_user(arg
, PAGE_SIZE
);
8312 if (IS_ERR(filter_str
))
8313 return PTR_ERR(filter_str
);
8315 if (IS_ENABLED(CONFIG_EVENT_TRACING
) &&
8316 event
->attr
.type
== PERF_TYPE_TRACEPOINT
)
8317 ret
= ftrace_profile_set_filter(event
, event
->attr
.config
,
8319 else if (has_addr_filter(event
))
8320 ret
= perf_event_set_addr_filter(event
, filter_str
);
8327 * hrtimer based swevent callback
8330 static enum hrtimer_restart
perf_swevent_hrtimer(struct hrtimer
*hrtimer
)
8332 enum hrtimer_restart ret
= HRTIMER_RESTART
;
8333 struct perf_sample_data data
;
8334 struct pt_regs
*regs
;
8335 struct perf_event
*event
;
8338 event
= container_of(hrtimer
, struct perf_event
, hw
.hrtimer
);
8340 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
8341 return HRTIMER_NORESTART
;
8343 event
->pmu
->read(event
);
8345 perf_sample_data_init(&data
, 0, event
->hw
.last_period
);
8346 regs
= get_irq_regs();
8348 if (regs
&& !perf_exclude_event(event
, regs
)) {
8349 if (!(event
->attr
.exclude_idle
&& is_idle_task(current
)))
8350 if (__perf_event_overflow(event
, 1, &data
, regs
))
8351 ret
= HRTIMER_NORESTART
;
8354 period
= max_t(u64
, 10000, event
->hw
.sample_period
);
8355 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
8360 static void perf_swevent_start_hrtimer(struct perf_event
*event
)
8362 struct hw_perf_event
*hwc
= &event
->hw
;
8365 if (!is_sampling_event(event
))
8368 period
= local64_read(&hwc
->period_left
);
8373 local64_set(&hwc
->period_left
, 0);
8375 period
= max_t(u64
, 10000, hwc
->sample_period
);
8377 hrtimer_start(&hwc
->hrtimer
, ns_to_ktime(period
),
8378 HRTIMER_MODE_REL_PINNED
);
8381 static void perf_swevent_cancel_hrtimer(struct perf_event
*event
)
8383 struct hw_perf_event
*hwc
= &event
->hw
;
8385 if (is_sampling_event(event
)) {
8386 ktime_t remaining
= hrtimer_get_remaining(&hwc
->hrtimer
);
8387 local64_set(&hwc
->period_left
, ktime_to_ns(remaining
));
8389 hrtimer_cancel(&hwc
->hrtimer
);
8393 static void perf_swevent_init_hrtimer(struct perf_event
*event
)
8395 struct hw_perf_event
*hwc
= &event
->hw
;
8397 if (!is_sampling_event(event
))
8400 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
8401 hwc
->hrtimer
.function
= perf_swevent_hrtimer
;
8404 * Since hrtimers have a fixed rate, we can do a static freq->period
8405 * mapping and avoid the whole period adjust feedback stuff.
8407 if (event
->attr
.freq
) {
8408 long freq
= event
->attr
.sample_freq
;
8410 event
->attr
.sample_period
= NSEC_PER_SEC
/ freq
;
8411 hwc
->sample_period
= event
->attr
.sample_period
;
8412 local64_set(&hwc
->period_left
, hwc
->sample_period
);
8413 hwc
->last_period
= hwc
->sample_period
;
8414 event
->attr
.freq
= 0;
8419 * Software event: cpu wall time clock
8422 static void cpu_clock_event_update(struct perf_event
*event
)
8427 now
= local_clock();
8428 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
8429 local64_add(now
- prev
, &event
->count
);
8432 static void cpu_clock_event_start(struct perf_event
*event
, int flags
)
8434 local64_set(&event
->hw
.prev_count
, local_clock());
8435 perf_swevent_start_hrtimer(event
);
8438 static void cpu_clock_event_stop(struct perf_event
*event
, int flags
)
8440 perf_swevent_cancel_hrtimer(event
);
8441 cpu_clock_event_update(event
);
8444 static int cpu_clock_event_add(struct perf_event
*event
, int flags
)
8446 if (flags
& PERF_EF_START
)
8447 cpu_clock_event_start(event
, flags
);
8448 perf_event_update_userpage(event
);
8453 static void cpu_clock_event_del(struct perf_event
*event
, int flags
)
8455 cpu_clock_event_stop(event
, flags
);
8458 static void cpu_clock_event_read(struct perf_event
*event
)
8460 cpu_clock_event_update(event
);
8463 static int cpu_clock_event_init(struct perf_event
*event
)
8465 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
8468 if (event
->attr
.config
!= PERF_COUNT_SW_CPU_CLOCK
)
8472 * no branch sampling for software events
8474 if (has_branch_stack(event
))
8477 perf_swevent_init_hrtimer(event
);
8482 static struct pmu perf_cpu_clock
= {
8483 .task_ctx_nr
= perf_sw_context
,
8485 .capabilities
= PERF_PMU_CAP_NO_NMI
,
8487 .event_init
= cpu_clock_event_init
,
8488 .add
= cpu_clock_event_add
,
8489 .del
= cpu_clock_event_del
,
8490 .start
= cpu_clock_event_start
,
8491 .stop
= cpu_clock_event_stop
,
8492 .read
= cpu_clock_event_read
,
8496 * Software event: task time clock
8499 static void task_clock_event_update(struct perf_event
*event
, u64 now
)
8504 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
8506 local64_add(delta
, &event
->count
);
8509 static void task_clock_event_start(struct perf_event
*event
, int flags
)
8511 local64_set(&event
->hw
.prev_count
, event
->ctx
->time
);
8512 perf_swevent_start_hrtimer(event
);
8515 static void task_clock_event_stop(struct perf_event
*event
, int flags
)
8517 perf_swevent_cancel_hrtimer(event
);
8518 task_clock_event_update(event
, event
->ctx
->time
);
8521 static int task_clock_event_add(struct perf_event
*event
, int flags
)
8523 if (flags
& PERF_EF_START
)
8524 task_clock_event_start(event
, flags
);
8525 perf_event_update_userpage(event
);
8530 static void task_clock_event_del(struct perf_event
*event
, int flags
)
8532 task_clock_event_stop(event
, PERF_EF_UPDATE
);
8535 static void task_clock_event_read(struct perf_event
*event
)
8537 u64 now
= perf_clock();
8538 u64 delta
= now
- event
->ctx
->timestamp
;
8539 u64 time
= event
->ctx
->time
+ delta
;
8541 task_clock_event_update(event
, time
);
8544 static int task_clock_event_init(struct perf_event
*event
)
8546 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
8549 if (event
->attr
.config
!= PERF_COUNT_SW_TASK_CLOCK
)
8553 * no branch sampling for software events
8555 if (has_branch_stack(event
))
8558 perf_swevent_init_hrtimer(event
);
8563 static struct pmu perf_task_clock
= {
8564 .task_ctx_nr
= perf_sw_context
,
8566 .capabilities
= PERF_PMU_CAP_NO_NMI
,
8568 .event_init
= task_clock_event_init
,
8569 .add
= task_clock_event_add
,
8570 .del
= task_clock_event_del
,
8571 .start
= task_clock_event_start
,
8572 .stop
= task_clock_event_stop
,
8573 .read
= task_clock_event_read
,
8576 static void perf_pmu_nop_void(struct pmu
*pmu
)
8580 static void perf_pmu_nop_txn(struct pmu
*pmu
, unsigned int flags
)
8584 static int perf_pmu_nop_int(struct pmu
*pmu
)
8589 static DEFINE_PER_CPU(unsigned int, nop_txn_flags
);
8591 static void perf_pmu_start_txn(struct pmu
*pmu
, unsigned int flags
)
8593 __this_cpu_write(nop_txn_flags
, flags
);
8595 if (flags
& ~PERF_PMU_TXN_ADD
)
8598 perf_pmu_disable(pmu
);
8601 static int perf_pmu_commit_txn(struct pmu
*pmu
)
8603 unsigned int flags
= __this_cpu_read(nop_txn_flags
);
8605 __this_cpu_write(nop_txn_flags
, 0);
8607 if (flags
& ~PERF_PMU_TXN_ADD
)
8610 perf_pmu_enable(pmu
);
8614 static void perf_pmu_cancel_txn(struct pmu
*pmu
)
8616 unsigned int flags
= __this_cpu_read(nop_txn_flags
);
8618 __this_cpu_write(nop_txn_flags
, 0);
8620 if (flags
& ~PERF_PMU_TXN_ADD
)
8623 perf_pmu_enable(pmu
);
8626 static int perf_event_idx_default(struct perf_event
*event
)
8632 * Ensures all contexts with the same task_ctx_nr have the same
8633 * pmu_cpu_context too.
8635 static struct perf_cpu_context __percpu
*find_pmu_context(int ctxn
)
8642 list_for_each_entry(pmu
, &pmus
, entry
) {
8643 if (pmu
->task_ctx_nr
== ctxn
)
8644 return pmu
->pmu_cpu_context
;
8650 static void update_pmu_context(struct pmu
*pmu
, struct pmu
*old_pmu
)
8654 for_each_possible_cpu(cpu
) {
8655 struct perf_cpu_context
*cpuctx
;
8657 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
8659 if (cpuctx
->unique_pmu
== old_pmu
)
8660 cpuctx
->unique_pmu
= pmu
;
8664 static void free_pmu_context(struct pmu
*pmu
)
8668 mutex_lock(&pmus_lock
);
8670 * Like a real lame refcount.
8672 list_for_each_entry(i
, &pmus
, entry
) {
8673 if (i
->pmu_cpu_context
== pmu
->pmu_cpu_context
) {
8674 update_pmu_context(i
, pmu
);
8679 free_percpu(pmu
->pmu_cpu_context
);
8681 mutex_unlock(&pmus_lock
);
8685 * Let userspace know that this PMU supports address range filtering:
8687 static ssize_t
nr_addr_filters_show(struct device
*dev
,
8688 struct device_attribute
*attr
,
8691 struct pmu
*pmu
= dev_get_drvdata(dev
);
8693 return snprintf(page
, PAGE_SIZE
- 1, "%d\n", pmu
->nr_addr_filters
);
8695 DEVICE_ATTR_RO(nr_addr_filters
);
8697 static struct idr pmu_idr
;
8700 type_show(struct device
*dev
, struct device_attribute
*attr
, char *page
)
8702 struct pmu
*pmu
= dev_get_drvdata(dev
);
8704 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->type
);
8706 static DEVICE_ATTR_RO(type
);
8709 perf_event_mux_interval_ms_show(struct device
*dev
,
8710 struct device_attribute
*attr
,
8713 struct pmu
*pmu
= dev_get_drvdata(dev
);
8715 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->hrtimer_interval_ms
);
8718 static DEFINE_MUTEX(mux_interval_mutex
);
8721 perf_event_mux_interval_ms_store(struct device
*dev
,
8722 struct device_attribute
*attr
,
8723 const char *buf
, size_t count
)
8725 struct pmu
*pmu
= dev_get_drvdata(dev
);
8726 int timer
, cpu
, ret
;
8728 ret
= kstrtoint(buf
, 0, &timer
);
8735 /* same value, noting to do */
8736 if (timer
== pmu
->hrtimer_interval_ms
)
8739 mutex_lock(&mux_interval_mutex
);
8740 pmu
->hrtimer_interval_ms
= timer
;
8742 /* update all cpuctx for this PMU */
8744 for_each_online_cpu(cpu
) {
8745 struct perf_cpu_context
*cpuctx
;
8746 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
8747 cpuctx
->hrtimer_interval
= ns_to_ktime(NSEC_PER_MSEC
* timer
);
8749 cpu_function_call(cpu
,
8750 (remote_function_f
)perf_mux_hrtimer_restart
, cpuctx
);
8753 mutex_unlock(&mux_interval_mutex
);
8757 static DEVICE_ATTR_RW(perf_event_mux_interval_ms
);
8759 static struct attribute
*pmu_dev_attrs
[] = {
8760 &dev_attr_type
.attr
,
8761 &dev_attr_perf_event_mux_interval_ms
.attr
,
8764 ATTRIBUTE_GROUPS(pmu_dev
);
8766 static int pmu_bus_running
;
8767 static struct bus_type pmu_bus
= {
8768 .name
= "event_source",
8769 .dev_groups
= pmu_dev_groups
,
8772 static void pmu_dev_release(struct device
*dev
)
8777 static int pmu_dev_alloc(struct pmu
*pmu
)
8781 pmu
->dev
= kzalloc(sizeof(struct device
), GFP_KERNEL
);
8785 pmu
->dev
->groups
= pmu
->attr_groups
;
8786 device_initialize(pmu
->dev
);
8787 ret
= dev_set_name(pmu
->dev
, "%s", pmu
->name
);
8791 dev_set_drvdata(pmu
->dev
, pmu
);
8792 pmu
->dev
->bus
= &pmu_bus
;
8793 pmu
->dev
->release
= pmu_dev_release
;
8794 ret
= device_add(pmu
->dev
);
8798 /* For PMUs with address filters, throw in an extra attribute: */
8799 if (pmu
->nr_addr_filters
)
8800 ret
= device_create_file(pmu
->dev
, &dev_attr_nr_addr_filters
);
8809 device_del(pmu
->dev
);
8812 put_device(pmu
->dev
);
8816 static struct lock_class_key cpuctx_mutex
;
8817 static struct lock_class_key cpuctx_lock
;
8819 int perf_pmu_register(struct pmu
*pmu
, const char *name
, int type
)
8823 mutex_lock(&pmus_lock
);
8825 pmu
->pmu_disable_count
= alloc_percpu(int);
8826 if (!pmu
->pmu_disable_count
)
8835 type
= idr_alloc(&pmu_idr
, pmu
, PERF_TYPE_MAX
, 0, GFP_KERNEL
);
8843 if (pmu_bus_running
) {
8844 ret
= pmu_dev_alloc(pmu
);
8850 if (pmu
->task_ctx_nr
== perf_hw_context
) {
8851 static int hw_context_taken
= 0;
8854 * Other than systems with heterogeneous CPUs, it never makes
8855 * sense for two PMUs to share perf_hw_context. PMUs which are
8856 * uncore must use perf_invalid_context.
8858 if (WARN_ON_ONCE(hw_context_taken
&&
8859 !(pmu
->capabilities
& PERF_PMU_CAP_HETEROGENEOUS_CPUS
)))
8860 pmu
->task_ctx_nr
= perf_invalid_context
;
8862 hw_context_taken
= 1;
8865 pmu
->pmu_cpu_context
= find_pmu_context(pmu
->task_ctx_nr
);
8866 if (pmu
->pmu_cpu_context
)
8867 goto got_cpu_context
;
8870 pmu
->pmu_cpu_context
= alloc_percpu(struct perf_cpu_context
);
8871 if (!pmu
->pmu_cpu_context
)
8874 for_each_possible_cpu(cpu
) {
8875 struct perf_cpu_context
*cpuctx
;
8877 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
8878 __perf_event_init_context(&cpuctx
->ctx
);
8879 lockdep_set_class(&cpuctx
->ctx
.mutex
, &cpuctx_mutex
);
8880 lockdep_set_class(&cpuctx
->ctx
.lock
, &cpuctx_lock
);
8881 cpuctx
->ctx
.pmu
= pmu
;
8883 __perf_mux_hrtimer_init(cpuctx
, cpu
);
8885 cpuctx
->unique_pmu
= pmu
;
8889 if (!pmu
->start_txn
) {
8890 if (pmu
->pmu_enable
) {
8892 * If we have pmu_enable/pmu_disable calls, install
8893 * transaction stubs that use that to try and batch
8894 * hardware accesses.
8896 pmu
->start_txn
= perf_pmu_start_txn
;
8897 pmu
->commit_txn
= perf_pmu_commit_txn
;
8898 pmu
->cancel_txn
= perf_pmu_cancel_txn
;
8900 pmu
->start_txn
= perf_pmu_nop_txn
;
8901 pmu
->commit_txn
= perf_pmu_nop_int
;
8902 pmu
->cancel_txn
= perf_pmu_nop_void
;
8906 if (!pmu
->pmu_enable
) {
8907 pmu
->pmu_enable
= perf_pmu_nop_void
;
8908 pmu
->pmu_disable
= perf_pmu_nop_void
;
8911 if (!pmu
->event_idx
)
8912 pmu
->event_idx
= perf_event_idx_default
;
8914 list_add_rcu(&pmu
->entry
, &pmus
);
8915 atomic_set(&pmu
->exclusive_cnt
, 0);
8918 mutex_unlock(&pmus_lock
);
8923 device_del(pmu
->dev
);
8924 put_device(pmu
->dev
);
8927 if (pmu
->type
>= PERF_TYPE_MAX
)
8928 idr_remove(&pmu_idr
, pmu
->type
);
8931 free_percpu(pmu
->pmu_disable_count
);
8934 EXPORT_SYMBOL_GPL(perf_pmu_register
);
8936 void perf_pmu_unregister(struct pmu
*pmu
)
8940 mutex_lock(&pmus_lock
);
8941 remove_device
= pmu_bus_running
;
8942 list_del_rcu(&pmu
->entry
);
8943 mutex_unlock(&pmus_lock
);
8946 * We dereference the pmu list under both SRCU and regular RCU, so
8947 * synchronize against both of those.
8949 synchronize_srcu(&pmus_srcu
);
8952 free_percpu(pmu
->pmu_disable_count
);
8953 if (pmu
->type
>= PERF_TYPE_MAX
)
8954 idr_remove(&pmu_idr
, pmu
->type
);
8955 if (remove_device
) {
8956 if (pmu
->nr_addr_filters
)
8957 device_remove_file(pmu
->dev
, &dev_attr_nr_addr_filters
);
8958 device_del(pmu
->dev
);
8959 put_device(pmu
->dev
);
8961 free_pmu_context(pmu
);
8963 EXPORT_SYMBOL_GPL(perf_pmu_unregister
);
8965 static int perf_try_init_event(struct pmu
*pmu
, struct perf_event
*event
)
8967 struct perf_event_context
*ctx
= NULL
;
8970 if (!try_module_get(pmu
->module
))
8973 if (event
->group_leader
!= event
) {
8975 * This ctx->mutex can nest when we're called through
8976 * inheritance. See the perf_event_ctx_lock_nested() comment.
8978 ctx
= perf_event_ctx_lock_nested(event
->group_leader
,
8979 SINGLE_DEPTH_NESTING
);
8984 ret
= pmu
->event_init(event
);
8987 perf_event_ctx_unlock(event
->group_leader
, ctx
);
8990 module_put(pmu
->module
);
8995 static struct pmu
*perf_init_event(struct perf_event
*event
)
8997 struct pmu
*pmu
= NULL
;
9001 idx
= srcu_read_lock(&pmus_srcu
);
9004 pmu
= idr_find(&pmu_idr
, event
->attr
.type
);
9007 ret
= perf_try_init_event(pmu
, event
);
9013 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
9014 ret
= perf_try_init_event(pmu
, event
);
9018 if (ret
!= -ENOENT
) {
9023 pmu
= ERR_PTR(-ENOENT
);
9025 srcu_read_unlock(&pmus_srcu
, idx
);
9030 static void attach_sb_event(struct perf_event
*event
)
9032 struct pmu_event_list
*pel
= per_cpu_ptr(&pmu_sb_events
, event
->cpu
);
9034 raw_spin_lock(&pel
->lock
);
9035 list_add_rcu(&event
->sb_list
, &pel
->list
);
9036 raw_spin_unlock(&pel
->lock
);
9040 * We keep a list of all !task (and therefore per-cpu) events
9041 * that need to receive side-band records.
9043 * This avoids having to scan all the various PMU per-cpu contexts
9046 static void account_pmu_sb_event(struct perf_event
*event
)
9048 if (is_sb_event(event
))
9049 attach_sb_event(event
);
9052 static void account_event_cpu(struct perf_event
*event
, int cpu
)
9057 if (is_cgroup_event(event
))
9058 atomic_inc(&per_cpu(perf_cgroup_events
, cpu
));
9061 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9062 static void account_freq_event_nohz(void)
9064 #ifdef CONFIG_NO_HZ_FULL
9065 /* Lock so we don't race with concurrent unaccount */
9066 spin_lock(&nr_freq_lock
);
9067 if (atomic_inc_return(&nr_freq_events
) == 1)
9068 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS
);
9069 spin_unlock(&nr_freq_lock
);
9073 static void account_freq_event(void)
9075 if (tick_nohz_full_enabled())
9076 account_freq_event_nohz();
9078 atomic_inc(&nr_freq_events
);
9082 static void account_event(struct perf_event
*event
)
9089 if (event
->attach_state
& PERF_ATTACH_TASK
)
9091 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
9092 atomic_inc(&nr_mmap_events
);
9093 if (event
->attr
.comm
)
9094 atomic_inc(&nr_comm_events
);
9095 if (event
->attr
.task
)
9096 atomic_inc(&nr_task_events
);
9097 if (event
->attr
.freq
)
9098 account_freq_event();
9099 if (event
->attr
.context_switch
) {
9100 atomic_inc(&nr_switch_events
);
9103 if (has_branch_stack(event
))
9105 if (is_cgroup_event(event
))
9109 if (atomic_inc_not_zero(&perf_sched_count
))
9112 mutex_lock(&perf_sched_mutex
);
9113 if (!atomic_read(&perf_sched_count
)) {
9114 static_branch_enable(&perf_sched_events
);
9116 * Guarantee that all CPUs observe they key change and
9117 * call the perf scheduling hooks before proceeding to
9118 * install events that need them.
9120 synchronize_sched();
9123 * Now that we have waited for the sync_sched(), allow further
9124 * increments to by-pass the mutex.
9126 atomic_inc(&perf_sched_count
);
9127 mutex_unlock(&perf_sched_mutex
);
9131 account_event_cpu(event
, event
->cpu
);
9133 account_pmu_sb_event(event
);
9137 * Allocate and initialize a event structure
9139 static struct perf_event
*
9140 perf_event_alloc(struct perf_event_attr
*attr
, int cpu
,
9141 struct task_struct
*task
,
9142 struct perf_event
*group_leader
,
9143 struct perf_event
*parent_event
,
9144 perf_overflow_handler_t overflow_handler
,
9145 void *context
, int cgroup_fd
)
9148 struct perf_event
*event
;
9149 struct hw_perf_event
*hwc
;
9152 if ((unsigned)cpu
>= nr_cpu_ids
) {
9153 if (!task
|| cpu
!= -1)
9154 return ERR_PTR(-EINVAL
);
9157 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
9159 return ERR_PTR(-ENOMEM
);
9162 * Single events are their own group leaders, with an
9163 * empty sibling list:
9166 group_leader
= event
;
9168 mutex_init(&event
->child_mutex
);
9169 INIT_LIST_HEAD(&event
->child_list
);
9171 INIT_LIST_HEAD(&event
->group_entry
);
9172 INIT_LIST_HEAD(&event
->event_entry
);
9173 INIT_LIST_HEAD(&event
->sibling_list
);
9174 INIT_LIST_HEAD(&event
->rb_entry
);
9175 INIT_LIST_HEAD(&event
->active_entry
);
9176 INIT_LIST_HEAD(&event
->addr_filters
.list
);
9177 INIT_HLIST_NODE(&event
->hlist_entry
);
9180 init_waitqueue_head(&event
->waitq
);
9181 init_irq_work(&event
->pending
, perf_pending_event
);
9183 mutex_init(&event
->mmap_mutex
);
9184 raw_spin_lock_init(&event
->addr_filters
.lock
);
9186 atomic_long_set(&event
->refcount
, 1);
9188 event
->attr
= *attr
;
9189 event
->group_leader
= group_leader
;
9193 event
->parent
= parent_event
;
9195 event
->ns
= get_pid_ns(task_active_pid_ns(current
));
9196 event
->id
= atomic64_inc_return(&perf_event_id
);
9198 event
->state
= PERF_EVENT_STATE_INACTIVE
;
9201 event
->attach_state
= PERF_ATTACH_TASK
;
9203 * XXX pmu::event_init needs to know what task to account to
9204 * and we cannot use the ctx information because we need the
9205 * pmu before we get a ctx.
9207 event
->hw
.target
= task
;
9210 event
->clock
= &local_clock
;
9212 event
->clock
= parent_event
->clock
;
9214 if (!overflow_handler
&& parent_event
) {
9215 overflow_handler
= parent_event
->overflow_handler
;
9216 context
= parent_event
->overflow_handler_context
;
9217 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9218 if (overflow_handler
== bpf_overflow_handler
) {
9219 struct bpf_prog
*prog
= bpf_prog_inc(parent_event
->prog
);
9222 err
= PTR_ERR(prog
);
9226 event
->orig_overflow_handler
=
9227 parent_event
->orig_overflow_handler
;
9232 if (overflow_handler
) {
9233 event
->overflow_handler
= overflow_handler
;
9234 event
->overflow_handler_context
= context
;
9235 } else if (is_write_backward(event
)){
9236 event
->overflow_handler
= perf_event_output_backward
;
9237 event
->overflow_handler_context
= NULL
;
9239 event
->overflow_handler
= perf_event_output_forward
;
9240 event
->overflow_handler_context
= NULL
;
9243 perf_event__state_init(event
);
9248 hwc
->sample_period
= attr
->sample_period
;
9249 if (attr
->freq
&& attr
->sample_freq
)
9250 hwc
->sample_period
= 1;
9251 hwc
->last_period
= hwc
->sample_period
;
9253 local64_set(&hwc
->period_left
, hwc
->sample_period
);
9256 * we currently do not support PERF_FORMAT_GROUP on inherited events
9258 if (attr
->inherit
&& (attr
->read_format
& PERF_FORMAT_GROUP
))
9261 if (!has_branch_stack(event
))
9262 event
->attr
.branch_sample_type
= 0;
9264 if (cgroup_fd
!= -1) {
9265 err
= perf_cgroup_connect(cgroup_fd
, event
, attr
, group_leader
);
9270 pmu
= perf_init_event(event
);
9273 else if (IS_ERR(pmu
)) {
9278 err
= exclusive_event_init(event
);
9282 if (has_addr_filter(event
)) {
9283 event
->addr_filters_offs
= kcalloc(pmu
->nr_addr_filters
,
9284 sizeof(unsigned long),
9286 if (!event
->addr_filters_offs
)
9289 /* force hw sync on the address filters */
9290 event
->addr_filters_gen
= 1;
9293 if (!event
->parent
) {
9294 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
) {
9295 err
= get_callchain_buffers(attr
->sample_max_stack
);
9297 goto err_addr_filters
;
9301 /* symmetric to unaccount_event() in _free_event() */
9302 account_event(event
);
9307 kfree(event
->addr_filters_offs
);
9310 exclusive_event_destroy(event
);
9314 event
->destroy(event
);
9315 module_put(pmu
->module
);
9317 if (is_cgroup_event(event
))
9318 perf_detach_cgroup(event
);
9320 put_pid_ns(event
->ns
);
9323 return ERR_PTR(err
);
9326 static int perf_copy_attr(struct perf_event_attr __user
*uattr
,
9327 struct perf_event_attr
*attr
)
9332 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
9336 * zero the full structure, so that a short copy will be nice.
9338 memset(attr
, 0, sizeof(*attr
));
9340 ret
= get_user(size
, &uattr
->size
);
9344 if (size
> PAGE_SIZE
) /* silly large */
9347 if (!size
) /* abi compat */
9348 size
= PERF_ATTR_SIZE_VER0
;
9350 if (size
< PERF_ATTR_SIZE_VER0
)
9354 * If we're handed a bigger struct than we know of,
9355 * ensure all the unknown bits are 0 - i.e. new
9356 * user-space does not rely on any kernel feature
9357 * extensions we dont know about yet.
9359 if (size
> sizeof(*attr
)) {
9360 unsigned char __user
*addr
;
9361 unsigned char __user
*end
;
9364 addr
= (void __user
*)uattr
+ sizeof(*attr
);
9365 end
= (void __user
*)uattr
+ size
;
9367 for (; addr
< end
; addr
++) {
9368 ret
= get_user(val
, addr
);
9374 size
= sizeof(*attr
);
9377 ret
= copy_from_user(attr
, uattr
, size
);
9381 if (attr
->__reserved_1
)
9384 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
9387 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
9390 if (attr
->sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
9391 u64 mask
= attr
->branch_sample_type
;
9393 /* only using defined bits */
9394 if (mask
& ~(PERF_SAMPLE_BRANCH_MAX
-1))
9397 /* at least one branch bit must be set */
9398 if (!(mask
& ~PERF_SAMPLE_BRANCH_PLM_ALL
))
9401 /* propagate priv level, when not set for branch */
9402 if (!(mask
& PERF_SAMPLE_BRANCH_PLM_ALL
)) {
9404 /* exclude_kernel checked on syscall entry */
9405 if (!attr
->exclude_kernel
)
9406 mask
|= PERF_SAMPLE_BRANCH_KERNEL
;
9408 if (!attr
->exclude_user
)
9409 mask
|= PERF_SAMPLE_BRANCH_USER
;
9411 if (!attr
->exclude_hv
)
9412 mask
|= PERF_SAMPLE_BRANCH_HV
;
9414 * adjust user setting (for HW filter setup)
9416 attr
->branch_sample_type
= mask
;
9418 /* privileged levels capture (kernel, hv): check permissions */
9419 if ((mask
& PERF_SAMPLE_BRANCH_PERM_PLM
)
9420 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
9424 if (attr
->sample_type
& PERF_SAMPLE_REGS_USER
) {
9425 ret
= perf_reg_validate(attr
->sample_regs_user
);
9430 if (attr
->sample_type
& PERF_SAMPLE_STACK_USER
) {
9431 if (!arch_perf_have_user_stack_dump())
9435 * We have __u32 type for the size, but so far
9436 * we can only use __u16 as maximum due to the
9437 * __u16 sample size limit.
9439 if (attr
->sample_stack_user
>= USHRT_MAX
)
9441 else if (!IS_ALIGNED(attr
->sample_stack_user
, sizeof(u64
)))
9445 if (attr
->sample_type
& PERF_SAMPLE_REGS_INTR
)
9446 ret
= perf_reg_validate(attr
->sample_regs_intr
);
9451 put_user(sizeof(*attr
), &uattr
->size
);
9457 perf_event_set_output(struct perf_event
*event
, struct perf_event
*output_event
)
9459 struct ring_buffer
*rb
= NULL
;
9465 /* don't allow circular references */
9466 if (event
== output_event
)
9470 * Don't allow cross-cpu buffers
9472 if (output_event
->cpu
!= event
->cpu
)
9476 * If its not a per-cpu rb, it must be the same task.
9478 if (output_event
->cpu
== -1 && output_event
->ctx
!= event
->ctx
)
9482 * Mixing clocks in the same buffer is trouble you don't need.
9484 if (output_event
->clock
!= event
->clock
)
9488 * Either writing ring buffer from beginning or from end.
9489 * Mixing is not allowed.
9491 if (is_write_backward(output_event
) != is_write_backward(event
))
9495 * If both events generate aux data, they must be on the same PMU
9497 if (has_aux(event
) && has_aux(output_event
) &&
9498 event
->pmu
!= output_event
->pmu
)
9502 mutex_lock(&event
->mmap_mutex
);
9503 /* Can't redirect output if we've got an active mmap() */
9504 if (atomic_read(&event
->mmap_count
))
9508 /* get the rb we want to redirect to */
9509 rb
= ring_buffer_get(output_event
);
9514 ring_buffer_attach(event
, rb
);
9518 mutex_unlock(&event
->mmap_mutex
);
9524 static void mutex_lock_double(struct mutex
*a
, struct mutex
*b
)
9530 mutex_lock_nested(b
, SINGLE_DEPTH_NESTING
);
9533 static int perf_event_set_clock(struct perf_event
*event
, clockid_t clk_id
)
9535 bool nmi_safe
= false;
9538 case CLOCK_MONOTONIC
:
9539 event
->clock
= &ktime_get_mono_fast_ns
;
9543 case CLOCK_MONOTONIC_RAW
:
9544 event
->clock
= &ktime_get_raw_fast_ns
;
9548 case CLOCK_REALTIME
:
9549 event
->clock
= &ktime_get_real_ns
;
9552 case CLOCK_BOOTTIME
:
9553 event
->clock
= &ktime_get_boot_ns
;
9557 event
->clock
= &ktime_get_tai_ns
;
9564 if (!nmi_safe
&& !(event
->pmu
->capabilities
& PERF_PMU_CAP_NO_NMI
))
9571 * Variation on perf_event_ctx_lock_nested(), except we take two context
9574 static struct perf_event_context
*
9575 __perf_event_ctx_lock_double(struct perf_event
*group_leader
,
9576 struct perf_event_context
*ctx
)
9578 struct perf_event_context
*gctx
;
9582 gctx
= READ_ONCE(group_leader
->ctx
);
9583 if (!atomic_inc_not_zero(&gctx
->refcount
)) {
9589 mutex_lock_double(&gctx
->mutex
, &ctx
->mutex
);
9591 if (group_leader
->ctx
!= gctx
) {
9592 mutex_unlock(&ctx
->mutex
);
9593 mutex_unlock(&gctx
->mutex
);
9602 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9604 * @attr_uptr: event_id type attributes for monitoring/sampling
9607 * @group_fd: group leader event fd
9609 SYSCALL_DEFINE5(perf_event_open
,
9610 struct perf_event_attr __user
*, attr_uptr
,
9611 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
9613 struct perf_event
*group_leader
= NULL
, *output_event
= NULL
;
9614 struct perf_event
*event
, *sibling
;
9615 struct perf_event_attr attr
;
9616 struct perf_event_context
*ctx
, *uninitialized_var(gctx
);
9617 struct file
*event_file
= NULL
;
9618 struct fd group
= {NULL
, 0};
9619 struct task_struct
*task
= NULL
;
9624 int f_flags
= O_RDWR
;
9627 /* for future expandability... */
9628 if (flags
& ~PERF_FLAG_ALL
)
9631 err
= perf_copy_attr(attr_uptr
, &attr
);
9635 if (!attr
.exclude_kernel
) {
9636 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
9641 if (attr
.sample_freq
> sysctl_perf_event_sample_rate
)
9644 if (attr
.sample_period
& (1ULL << 63))
9648 if (!attr
.sample_max_stack
)
9649 attr
.sample_max_stack
= sysctl_perf_event_max_stack
;
9652 * In cgroup mode, the pid argument is used to pass the fd
9653 * opened to the cgroup directory in cgroupfs. The cpu argument
9654 * designates the cpu on which to monitor threads from that
9657 if ((flags
& PERF_FLAG_PID_CGROUP
) && (pid
== -1 || cpu
== -1))
9660 if (flags
& PERF_FLAG_FD_CLOEXEC
)
9661 f_flags
|= O_CLOEXEC
;
9663 event_fd
= get_unused_fd_flags(f_flags
);
9667 if (group_fd
!= -1) {
9668 err
= perf_fget_light(group_fd
, &group
);
9671 group_leader
= group
.file
->private_data
;
9672 if (flags
& PERF_FLAG_FD_OUTPUT
)
9673 output_event
= group_leader
;
9674 if (flags
& PERF_FLAG_FD_NO_GROUP
)
9675 group_leader
= NULL
;
9678 if (pid
!= -1 && !(flags
& PERF_FLAG_PID_CGROUP
)) {
9679 task
= find_lively_task_by_vpid(pid
);
9681 err
= PTR_ERR(task
);
9686 if (task
&& group_leader
&&
9687 group_leader
->attr
.inherit
!= attr
.inherit
) {
9695 err
= mutex_lock_interruptible(&task
->signal
->cred_guard_mutex
);
9700 * Reuse ptrace permission checks for now.
9702 * We must hold cred_guard_mutex across this and any potential
9703 * perf_install_in_context() call for this new event to
9704 * serialize against exec() altering our credentials (and the
9705 * perf_event_exit_task() that could imply).
9708 if (!ptrace_may_access(task
, PTRACE_MODE_READ_REALCREDS
))
9712 if (flags
& PERF_FLAG_PID_CGROUP
)
9715 event
= perf_event_alloc(&attr
, cpu
, task
, group_leader
, NULL
,
9716 NULL
, NULL
, cgroup_fd
);
9717 if (IS_ERR(event
)) {
9718 err
= PTR_ERR(event
);
9722 if (is_sampling_event(event
)) {
9723 if (event
->pmu
->capabilities
& PERF_PMU_CAP_NO_INTERRUPT
) {
9730 * Special case software events and allow them to be part of
9731 * any hardware group.
9735 if (attr
.use_clockid
) {
9736 err
= perf_event_set_clock(event
, attr
.clockid
);
9741 if (pmu
->task_ctx_nr
== perf_sw_context
)
9742 event
->event_caps
|= PERF_EV_CAP_SOFTWARE
;
9745 (is_software_event(event
) != is_software_event(group_leader
))) {
9746 if (is_software_event(event
)) {
9748 * If event and group_leader are not both a software
9749 * event, and event is, then group leader is not.
9751 * Allow the addition of software events to !software
9752 * groups, this is safe because software events never
9755 pmu
= group_leader
->pmu
;
9756 } else if (is_software_event(group_leader
) &&
9757 (group_leader
->group_caps
& PERF_EV_CAP_SOFTWARE
)) {
9759 * In case the group is a pure software group, and we
9760 * try to add a hardware event, move the whole group to
9761 * the hardware context.
9768 * Get the target context (task or percpu):
9770 ctx
= find_get_context(pmu
, task
, event
);
9776 if ((pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
) && group_leader
) {
9782 * Look up the group leader (we will attach this event to it):
9788 * Do not allow a recursive hierarchy (this new sibling
9789 * becoming part of another group-sibling):
9791 if (group_leader
->group_leader
!= group_leader
)
9794 /* All events in a group should have the same clock */
9795 if (group_leader
->clock
!= event
->clock
)
9799 * Do not allow to attach to a group in a different
9800 * task or CPU context:
9804 * Make sure we're both on the same task, or both
9807 if (group_leader
->ctx
->task
!= ctx
->task
)
9811 * Make sure we're both events for the same CPU;
9812 * grouping events for different CPUs is broken; since
9813 * you can never concurrently schedule them anyhow.
9815 if (group_leader
->cpu
!= event
->cpu
)
9818 if (group_leader
->ctx
!= ctx
)
9823 * Only a group leader can be exclusive or pinned
9825 if (attr
.exclusive
|| attr
.pinned
)
9830 err
= perf_event_set_output(event
, output_event
);
9835 event_file
= anon_inode_getfile("[perf_event]", &perf_fops
, event
,
9837 if (IS_ERR(event_file
)) {
9838 err
= PTR_ERR(event_file
);
9844 gctx
= __perf_event_ctx_lock_double(group_leader
, ctx
);
9846 if (gctx
->task
== TASK_TOMBSTONE
) {
9852 * Check if we raced against another sys_perf_event_open() call
9853 * moving the software group underneath us.
9855 if (!(group_leader
->group_caps
& PERF_EV_CAP_SOFTWARE
)) {
9857 * If someone moved the group out from under us, check
9858 * if this new event wound up on the same ctx, if so
9859 * its the regular !move_group case, otherwise fail.
9865 perf_event_ctx_unlock(group_leader
, gctx
);
9870 mutex_lock(&ctx
->mutex
);
9873 if (ctx
->task
== TASK_TOMBSTONE
) {
9878 if (!perf_event_validate_size(event
)) {
9884 * Must be under the same ctx::mutex as perf_install_in_context(),
9885 * because we need to serialize with concurrent event creation.
9887 if (!exclusive_event_installable(event
, ctx
)) {
9888 /* exclusive and group stuff are assumed mutually exclusive */
9889 WARN_ON_ONCE(move_group
);
9895 WARN_ON_ONCE(ctx
->parent_ctx
);
9898 * This is the point on no return; we cannot fail hereafter. This is
9899 * where we start modifying current state.
9904 * See perf_event_ctx_lock() for comments on the details
9905 * of swizzling perf_event::ctx.
9907 perf_remove_from_context(group_leader
, 0);
9909 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
9911 perf_remove_from_context(sibling
, 0);
9916 * Wait for everybody to stop referencing the events through
9917 * the old lists, before installing it on new lists.
9922 * Install the group siblings before the group leader.
9924 * Because a group leader will try and install the entire group
9925 * (through the sibling list, which is still in-tact), we can
9926 * end up with siblings installed in the wrong context.
9928 * By installing siblings first we NO-OP because they're not
9929 * reachable through the group lists.
9931 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
9933 perf_event__state_init(sibling
);
9934 perf_install_in_context(ctx
, sibling
, sibling
->cpu
);
9939 * Removing from the context ends up with disabled
9940 * event. What we want here is event in the initial
9941 * startup state, ready to be add into new context.
9943 perf_event__state_init(group_leader
);
9944 perf_install_in_context(ctx
, group_leader
, group_leader
->cpu
);
9948 * Now that all events are installed in @ctx, nothing
9949 * references @gctx anymore, so drop the last reference we have
9956 * Precalculate sample_data sizes; do while holding ctx::mutex such
9957 * that we're serialized against further additions and before
9958 * perf_install_in_context() which is the point the event is active and
9959 * can use these values.
9961 perf_event__header_size(event
);
9962 perf_event__id_header_size(event
);
9964 event
->owner
= current
;
9966 perf_install_in_context(ctx
, event
, event
->cpu
);
9967 perf_unpin_context(ctx
);
9970 perf_event_ctx_unlock(group_leader
, gctx
);
9971 mutex_unlock(&ctx
->mutex
);
9974 mutex_unlock(&task
->signal
->cred_guard_mutex
);
9975 put_task_struct(task
);
9980 mutex_lock(¤t
->perf_event_mutex
);
9981 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
9982 mutex_unlock(¤t
->perf_event_mutex
);
9985 * Drop the reference on the group_event after placing the
9986 * new event on the sibling_list. This ensures destruction
9987 * of the group leader will find the pointer to itself in
9988 * perf_group_detach().
9991 fd_install(event_fd
, event_file
);
9996 perf_event_ctx_unlock(group_leader
, gctx
);
9997 mutex_unlock(&ctx
->mutex
);
10001 perf_unpin_context(ctx
);
10005 * If event_file is set, the fput() above will have called ->release()
10006 * and that will take care of freeing the event.
10012 mutex_unlock(&task
->signal
->cred_guard_mutex
);
10017 put_task_struct(task
);
10021 put_unused_fd(event_fd
);
10026 * perf_event_create_kernel_counter
10028 * @attr: attributes of the counter to create
10029 * @cpu: cpu in which the counter is bound
10030 * @task: task to profile (NULL for percpu)
10032 struct perf_event
*
10033 perf_event_create_kernel_counter(struct perf_event_attr
*attr
, int cpu
,
10034 struct task_struct
*task
,
10035 perf_overflow_handler_t overflow_handler
,
10038 struct perf_event_context
*ctx
;
10039 struct perf_event
*event
;
10043 * Get the target context (task or percpu):
10046 event
= perf_event_alloc(attr
, cpu
, task
, NULL
, NULL
,
10047 overflow_handler
, context
, -1);
10048 if (IS_ERR(event
)) {
10049 err
= PTR_ERR(event
);
10053 /* Mark owner so we could distinguish it from user events. */
10054 event
->owner
= TASK_TOMBSTONE
;
10056 ctx
= find_get_context(event
->pmu
, task
, event
);
10058 err
= PTR_ERR(ctx
);
10062 WARN_ON_ONCE(ctx
->parent_ctx
);
10063 mutex_lock(&ctx
->mutex
);
10064 if (ctx
->task
== TASK_TOMBSTONE
) {
10069 if (!exclusive_event_installable(event
, ctx
)) {
10074 perf_install_in_context(ctx
, event
, cpu
);
10075 perf_unpin_context(ctx
);
10076 mutex_unlock(&ctx
->mutex
);
10081 mutex_unlock(&ctx
->mutex
);
10082 perf_unpin_context(ctx
);
10087 return ERR_PTR(err
);
10089 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter
);
10091 void perf_pmu_migrate_context(struct pmu
*pmu
, int src_cpu
, int dst_cpu
)
10093 struct perf_event_context
*src_ctx
;
10094 struct perf_event_context
*dst_ctx
;
10095 struct perf_event
*event
, *tmp
;
10098 src_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, src_cpu
)->ctx
;
10099 dst_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, dst_cpu
)->ctx
;
10102 * See perf_event_ctx_lock() for comments on the details
10103 * of swizzling perf_event::ctx.
10105 mutex_lock_double(&src_ctx
->mutex
, &dst_ctx
->mutex
);
10106 list_for_each_entry_safe(event
, tmp
, &src_ctx
->event_list
,
10108 perf_remove_from_context(event
, 0);
10109 unaccount_event_cpu(event
, src_cpu
);
10111 list_add(&event
->migrate_entry
, &events
);
10115 * Wait for the events to quiesce before re-instating them.
10120 * Re-instate events in 2 passes.
10122 * Skip over group leaders and only install siblings on this first
10123 * pass, siblings will not get enabled without a leader, however a
10124 * leader will enable its siblings, even if those are still on the old
10127 list_for_each_entry_safe(event
, tmp
, &events
, migrate_entry
) {
10128 if (event
->group_leader
== event
)
10131 list_del(&event
->migrate_entry
);
10132 if (event
->state
>= PERF_EVENT_STATE_OFF
)
10133 event
->state
= PERF_EVENT_STATE_INACTIVE
;
10134 account_event_cpu(event
, dst_cpu
);
10135 perf_install_in_context(dst_ctx
, event
, dst_cpu
);
10140 * Once all the siblings are setup properly, install the group leaders
10143 list_for_each_entry_safe(event
, tmp
, &events
, migrate_entry
) {
10144 list_del(&event
->migrate_entry
);
10145 if (event
->state
>= PERF_EVENT_STATE_OFF
)
10146 event
->state
= PERF_EVENT_STATE_INACTIVE
;
10147 account_event_cpu(event
, dst_cpu
);
10148 perf_install_in_context(dst_ctx
, event
, dst_cpu
);
10151 mutex_unlock(&dst_ctx
->mutex
);
10152 mutex_unlock(&src_ctx
->mutex
);
10154 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context
);
10156 static void sync_child_event(struct perf_event
*child_event
,
10157 struct task_struct
*child
)
10159 struct perf_event
*parent_event
= child_event
->parent
;
10162 if (child_event
->attr
.inherit_stat
)
10163 perf_event_read_event(child_event
, child
);
10165 child_val
= perf_event_count(child_event
);
10168 * Add back the child's count to the parent's count:
10170 atomic64_add(child_val
, &parent_event
->child_count
);
10171 atomic64_add(child_event
->total_time_enabled
,
10172 &parent_event
->child_total_time_enabled
);
10173 atomic64_add(child_event
->total_time_running
,
10174 &parent_event
->child_total_time_running
);
10178 perf_event_exit_event(struct perf_event
*child_event
,
10179 struct perf_event_context
*child_ctx
,
10180 struct task_struct
*child
)
10182 struct perf_event
*parent_event
= child_event
->parent
;
10185 * Do not destroy the 'original' grouping; because of the context
10186 * switch optimization the original events could've ended up in a
10187 * random child task.
10189 * If we were to destroy the original group, all group related
10190 * operations would cease to function properly after this random
10193 * Do destroy all inherited groups, we don't care about those
10194 * and being thorough is better.
10196 raw_spin_lock_irq(&child_ctx
->lock
);
10197 WARN_ON_ONCE(child_ctx
->is_active
);
10200 perf_group_detach(child_event
);
10201 list_del_event(child_event
, child_ctx
);
10202 child_event
->state
= PERF_EVENT_STATE_EXIT
; /* is_event_hup() */
10203 raw_spin_unlock_irq(&child_ctx
->lock
);
10206 * Parent events are governed by their filedesc, retain them.
10208 if (!parent_event
) {
10209 perf_event_wakeup(child_event
);
10213 * Child events can be cleaned up.
10216 sync_child_event(child_event
, child
);
10219 * Remove this event from the parent's list
10221 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
10222 mutex_lock(&parent_event
->child_mutex
);
10223 list_del_init(&child_event
->child_list
);
10224 mutex_unlock(&parent_event
->child_mutex
);
10227 * Kick perf_poll() for is_event_hup().
10229 perf_event_wakeup(parent_event
);
10230 free_event(child_event
);
10231 put_event(parent_event
);
10234 static void perf_event_exit_task_context(struct task_struct
*child
, int ctxn
)
10236 struct perf_event_context
*child_ctx
, *clone_ctx
= NULL
;
10237 struct perf_event
*child_event
, *next
;
10239 WARN_ON_ONCE(child
!= current
);
10241 child_ctx
= perf_pin_task_context(child
, ctxn
);
10246 * In order to reduce the amount of tricky in ctx tear-down, we hold
10247 * ctx::mutex over the entire thing. This serializes against almost
10248 * everything that wants to access the ctx.
10250 * The exception is sys_perf_event_open() /
10251 * perf_event_create_kernel_count() which does find_get_context()
10252 * without ctx::mutex (it cannot because of the move_group double mutex
10253 * lock thing). See the comments in perf_install_in_context().
10255 mutex_lock(&child_ctx
->mutex
);
10258 * In a single ctx::lock section, de-schedule the events and detach the
10259 * context from the task such that we cannot ever get it scheduled back
10262 raw_spin_lock_irq(&child_ctx
->lock
);
10263 task_ctx_sched_out(__get_cpu_context(child_ctx
), child_ctx
);
10266 * Now that the context is inactive, destroy the task <-> ctx relation
10267 * and mark the context dead.
10269 RCU_INIT_POINTER(child
->perf_event_ctxp
[ctxn
], NULL
);
10270 put_ctx(child_ctx
); /* cannot be last */
10271 WRITE_ONCE(child_ctx
->task
, TASK_TOMBSTONE
);
10272 put_task_struct(current
); /* cannot be last */
10274 clone_ctx
= unclone_ctx(child_ctx
);
10275 raw_spin_unlock_irq(&child_ctx
->lock
);
10278 put_ctx(clone_ctx
);
10281 * Report the task dead after unscheduling the events so that we
10282 * won't get any samples after PERF_RECORD_EXIT. We can however still
10283 * get a few PERF_RECORD_READ events.
10285 perf_event_task(child
, child_ctx
, 0);
10287 list_for_each_entry_safe(child_event
, next
, &child_ctx
->event_list
, event_entry
)
10288 perf_event_exit_event(child_event
, child_ctx
, child
);
10290 mutex_unlock(&child_ctx
->mutex
);
10292 put_ctx(child_ctx
);
10296 * When a child task exits, feed back event values to parent events.
10298 * Can be called with cred_guard_mutex held when called from
10299 * install_exec_creds().
10301 void perf_event_exit_task(struct task_struct
*child
)
10303 struct perf_event
*event
, *tmp
;
10306 mutex_lock(&child
->perf_event_mutex
);
10307 list_for_each_entry_safe(event
, tmp
, &child
->perf_event_list
,
10309 list_del_init(&event
->owner_entry
);
10312 * Ensure the list deletion is visible before we clear
10313 * the owner, closes a race against perf_release() where
10314 * we need to serialize on the owner->perf_event_mutex.
10316 smp_store_release(&event
->owner
, NULL
);
10318 mutex_unlock(&child
->perf_event_mutex
);
10320 for_each_task_context_nr(ctxn
)
10321 perf_event_exit_task_context(child
, ctxn
);
10324 * The perf_event_exit_task_context calls perf_event_task
10325 * with child's task_ctx, which generates EXIT events for
10326 * child contexts and sets child->perf_event_ctxp[] to NULL.
10327 * At this point we need to send EXIT events to cpu contexts.
10329 perf_event_task(child
, NULL
, 0);
10332 static void perf_free_event(struct perf_event
*event
,
10333 struct perf_event_context
*ctx
)
10335 struct perf_event
*parent
= event
->parent
;
10337 if (WARN_ON_ONCE(!parent
))
10340 mutex_lock(&parent
->child_mutex
);
10341 list_del_init(&event
->child_list
);
10342 mutex_unlock(&parent
->child_mutex
);
10346 raw_spin_lock_irq(&ctx
->lock
);
10347 perf_group_detach(event
);
10348 list_del_event(event
, ctx
);
10349 raw_spin_unlock_irq(&ctx
->lock
);
10354 * Free an unexposed, unused context as created by inheritance by
10355 * perf_event_init_task below, used by fork() in case of fail.
10357 * Not all locks are strictly required, but take them anyway to be nice and
10358 * help out with the lockdep assertions.
10360 void perf_event_free_task(struct task_struct
*task
)
10362 struct perf_event_context
*ctx
;
10363 struct perf_event
*event
, *tmp
;
10366 for_each_task_context_nr(ctxn
) {
10367 ctx
= task
->perf_event_ctxp
[ctxn
];
10371 mutex_lock(&ctx
->mutex
);
10373 list_for_each_entry_safe(event
, tmp
, &ctx
->pinned_groups
,
10375 perf_free_event(event
, ctx
);
10377 list_for_each_entry_safe(event
, tmp
, &ctx
->flexible_groups
,
10379 perf_free_event(event
, ctx
);
10381 if (!list_empty(&ctx
->pinned_groups
) ||
10382 !list_empty(&ctx
->flexible_groups
))
10385 mutex_unlock(&ctx
->mutex
);
10391 void perf_event_delayed_put(struct task_struct
*task
)
10395 for_each_task_context_nr(ctxn
)
10396 WARN_ON_ONCE(task
->perf_event_ctxp
[ctxn
]);
10399 struct file
*perf_event_get(unsigned int fd
)
10403 file
= fget_raw(fd
);
10405 return ERR_PTR(-EBADF
);
10407 if (file
->f_op
!= &perf_fops
) {
10409 return ERR_PTR(-EBADF
);
10415 const struct perf_event_attr
*perf_event_attrs(struct perf_event
*event
)
10418 return ERR_PTR(-EINVAL
);
10420 return &event
->attr
;
10424 * inherit a event from parent task to child task:
10426 static struct perf_event
*
10427 inherit_event(struct perf_event
*parent_event
,
10428 struct task_struct
*parent
,
10429 struct perf_event_context
*parent_ctx
,
10430 struct task_struct
*child
,
10431 struct perf_event
*group_leader
,
10432 struct perf_event_context
*child_ctx
)
10434 enum perf_event_active_state parent_state
= parent_event
->state
;
10435 struct perf_event
*child_event
;
10436 unsigned long flags
;
10439 * Instead of creating recursive hierarchies of events,
10440 * we link inherited events back to the original parent,
10441 * which has a filp for sure, which we use as the reference
10444 if (parent_event
->parent
)
10445 parent_event
= parent_event
->parent
;
10447 child_event
= perf_event_alloc(&parent_event
->attr
,
10450 group_leader
, parent_event
,
10452 if (IS_ERR(child_event
))
10453 return child_event
;
10456 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10457 * must be under the same lock in order to serialize against
10458 * perf_event_release_kernel(), such that either we must observe
10459 * is_orphaned_event() or they will observe us on the child_list.
10461 mutex_lock(&parent_event
->child_mutex
);
10462 if (is_orphaned_event(parent_event
) ||
10463 !atomic_long_inc_not_zero(&parent_event
->refcount
)) {
10464 mutex_unlock(&parent_event
->child_mutex
);
10465 free_event(child_event
);
10469 get_ctx(child_ctx
);
10472 * Make the child state follow the state of the parent event,
10473 * not its attr.disabled bit. We hold the parent's mutex,
10474 * so we won't race with perf_event_{en, dis}able_family.
10476 if (parent_state
>= PERF_EVENT_STATE_INACTIVE
)
10477 child_event
->state
= PERF_EVENT_STATE_INACTIVE
;
10479 child_event
->state
= PERF_EVENT_STATE_OFF
;
10481 if (parent_event
->attr
.freq
) {
10482 u64 sample_period
= parent_event
->hw
.sample_period
;
10483 struct hw_perf_event
*hwc
= &child_event
->hw
;
10485 hwc
->sample_period
= sample_period
;
10486 hwc
->last_period
= sample_period
;
10488 local64_set(&hwc
->period_left
, sample_period
);
10491 child_event
->ctx
= child_ctx
;
10492 child_event
->overflow_handler
= parent_event
->overflow_handler
;
10493 child_event
->overflow_handler_context
10494 = parent_event
->overflow_handler_context
;
10497 * Precalculate sample_data sizes
10499 perf_event__header_size(child_event
);
10500 perf_event__id_header_size(child_event
);
10503 * Link it up in the child's context:
10505 raw_spin_lock_irqsave(&child_ctx
->lock
, flags
);
10506 add_event_to_ctx(child_event
, child_ctx
);
10507 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
10510 * Link this into the parent event's child list
10512 list_add_tail(&child_event
->child_list
, &parent_event
->child_list
);
10513 mutex_unlock(&parent_event
->child_mutex
);
10515 return child_event
;
10518 static int inherit_group(struct perf_event
*parent_event
,
10519 struct task_struct
*parent
,
10520 struct perf_event_context
*parent_ctx
,
10521 struct task_struct
*child
,
10522 struct perf_event_context
*child_ctx
)
10524 struct perf_event
*leader
;
10525 struct perf_event
*sub
;
10526 struct perf_event
*child_ctr
;
10528 leader
= inherit_event(parent_event
, parent
, parent_ctx
,
10529 child
, NULL
, child_ctx
);
10530 if (IS_ERR(leader
))
10531 return PTR_ERR(leader
);
10532 list_for_each_entry(sub
, &parent_event
->sibling_list
, group_entry
) {
10533 child_ctr
= inherit_event(sub
, parent
, parent_ctx
,
10534 child
, leader
, child_ctx
);
10535 if (IS_ERR(child_ctr
))
10536 return PTR_ERR(child_ctr
);
10542 inherit_task_group(struct perf_event
*event
, struct task_struct
*parent
,
10543 struct perf_event_context
*parent_ctx
,
10544 struct task_struct
*child
, int ctxn
,
10545 int *inherited_all
)
10548 struct perf_event_context
*child_ctx
;
10550 if (!event
->attr
.inherit
) {
10551 *inherited_all
= 0;
10555 child_ctx
= child
->perf_event_ctxp
[ctxn
];
10558 * This is executed from the parent task context, so
10559 * inherit events that have been marked for cloning.
10560 * First allocate and initialize a context for the
10564 child_ctx
= alloc_perf_context(parent_ctx
->pmu
, child
);
10568 child
->perf_event_ctxp
[ctxn
] = child_ctx
;
10571 ret
= inherit_group(event
, parent
, parent_ctx
,
10575 *inherited_all
= 0;
10581 * Initialize the perf_event context in task_struct
10583 static int perf_event_init_context(struct task_struct
*child
, int ctxn
)
10585 struct perf_event_context
*child_ctx
, *parent_ctx
;
10586 struct perf_event_context
*cloned_ctx
;
10587 struct perf_event
*event
;
10588 struct task_struct
*parent
= current
;
10589 int inherited_all
= 1;
10590 unsigned long flags
;
10593 if (likely(!parent
->perf_event_ctxp
[ctxn
]))
10597 * If the parent's context is a clone, pin it so it won't get
10598 * swapped under us.
10600 parent_ctx
= perf_pin_task_context(parent
, ctxn
);
10605 * No need to check if parent_ctx != NULL here; since we saw
10606 * it non-NULL earlier, the only reason for it to become NULL
10607 * is if we exit, and since we're currently in the middle of
10608 * a fork we can't be exiting at the same time.
10612 * Lock the parent list. No need to lock the child - not PID
10613 * hashed yet and not running, so nobody can access it.
10615 mutex_lock(&parent_ctx
->mutex
);
10618 * We dont have to disable NMIs - we are only looking at
10619 * the list, not manipulating it:
10621 list_for_each_entry(event
, &parent_ctx
->pinned_groups
, group_entry
) {
10622 ret
= inherit_task_group(event
, parent
, parent_ctx
,
10623 child
, ctxn
, &inherited_all
);
10629 * We can't hold ctx->lock when iterating the ->flexible_group list due
10630 * to allocations, but we need to prevent rotation because
10631 * rotate_ctx() will change the list from interrupt context.
10633 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
10634 parent_ctx
->rotate_disable
= 1;
10635 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
10637 list_for_each_entry(event
, &parent_ctx
->flexible_groups
, group_entry
) {
10638 ret
= inherit_task_group(event
, parent
, parent_ctx
,
10639 child
, ctxn
, &inherited_all
);
10644 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
10645 parent_ctx
->rotate_disable
= 0;
10647 child_ctx
= child
->perf_event_ctxp
[ctxn
];
10649 if (child_ctx
&& inherited_all
) {
10651 * Mark the child context as a clone of the parent
10652 * context, or of whatever the parent is a clone of.
10654 * Note that if the parent is a clone, the holding of
10655 * parent_ctx->lock avoids it from being uncloned.
10657 cloned_ctx
= parent_ctx
->parent_ctx
;
10659 child_ctx
->parent_ctx
= cloned_ctx
;
10660 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
10662 child_ctx
->parent_ctx
= parent_ctx
;
10663 child_ctx
->parent_gen
= parent_ctx
->generation
;
10665 get_ctx(child_ctx
->parent_ctx
);
10668 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
10669 mutex_unlock(&parent_ctx
->mutex
);
10671 perf_unpin_context(parent_ctx
);
10672 put_ctx(parent_ctx
);
10678 * Initialize the perf_event context in task_struct
10680 int perf_event_init_task(struct task_struct
*child
)
10684 memset(child
->perf_event_ctxp
, 0, sizeof(child
->perf_event_ctxp
));
10685 mutex_init(&child
->perf_event_mutex
);
10686 INIT_LIST_HEAD(&child
->perf_event_list
);
10688 for_each_task_context_nr(ctxn
) {
10689 ret
= perf_event_init_context(child
, ctxn
);
10691 perf_event_free_task(child
);
10699 static void __init
perf_event_init_all_cpus(void)
10701 struct swevent_htable
*swhash
;
10704 for_each_possible_cpu(cpu
) {
10705 swhash
= &per_cpu(swevent_htable
, cpu
);
10706 mutex_init(&swhash
->hlist_mutex
);
10707 INIT_LIST_HEAD(&per_cpu(active_ctx_list
, cpu
));
10709 INIT_LIST_HEAD(&per_cpu(pmu_sb_events
.list
, cpu
));
10710 raw_spin_lock_init(&per_cpu(pmu_sb_events
.lock
, cpu
));
10712 INIT_LIST_HEAD(&per_cpu(sched_cb_list
, cpu
));
10716 int perf_event_init_cpu(unsigned int cpu
)
10718 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
10720 mutex_lock(&swhash
->hlist_mutex
);
10721 if (swhash
->hlist_refcount
> 0 && !swevent_hlist_deref(swhash
)) {
10722 struct swevent_hlist
*hlist
;
10724 hlist
= kzalloc_node(sizeof(*hlist
), GFP_KERNEL
, cpu_to_node(cpu
));
10726 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
10728 mutex_unlock(&swhash
->hlist_mutex
);
10732 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
10733 static void __perf_event_exit_context(void *__info
)
10735 struct perf_event_context
*ctx
= __info
;
10736 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
10737 struct perf_event
*event
;
10739 raw_spin_lock(&ctx
->lock
);
10740 list_for_each_entry(event
, &ctx
->event_list
, event_entry
)
10741 __perf_remove_from_context(event
, cpuctx
, ctx
, (void *)DETACH_GROUP
);
10742 raw_spin_unlock(&ctx
->lock
);
10745 static void perf_event_exit_cpu_context(int cpu
)
10747 struct perf_event_context
*ctx
;
10751 idx
= srcu_read_lock(&pmus_srcu
);
10752 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
10753 ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
)->ctx
;
10755 mutex_lock(&ctx
->mutex
);
10756 smp_call_function_single(cpu
, __perf_event_exit_context
, ctx
, 1);
10757 mutex_unlock(&ctx
->mutex
);
10759 srcu_read_unlock(&pmus_srcu
, idx
);
10763 static void perf_event_exit_cpu_context(int cpu
) { }
10767 int perf_event_exit_cpu(unsigned int cpu
)
10769 perf_event_exit_cpu_context(cpu
);
10774 perf_reboot(struct notifier_block
*notifier
, unsigned long val
, void *v
)
10778 for_each_online_cpu(cpu
)
10779 perf_event_exit_cpu(cpu
);
10785 * Run the perf reboot notifier at the very last possible moment so that
10786 * the generic watchdog code runs as long as possible.
10788 static struct notifier_block perf_reboot_notifier
= {
10789 .notifier_call
= perf_reboot
,
10790 .priority
= INT_MIN
,
10793 void __init
perf_event_init(void)
10797 idr_init(&pmu_idr
);
10799 perf_event_init_all_cpus();
10800 init_srcu_struct(&pmus_srcu
);
10801 perf_pmu_register(&perf_swevent
, "software", PERF_TYPE_SOFTWARE
);
10802 perf_pmu_register(&perf_cpu_clock
, NULL
, -1);
10803 perf_pmu_register(&perf_task_clock
, NULL
, -1);
10804 perf_tp_register();
10805 perf_event_init_cpu(smp_processor_id());
10806 register_reboot_notifier(&perf_reboot_notifier
);
10808 ret
= init_hw_breakpoint();
10809 WARN(ret
, "hw_breakpoint initialization failed with: %d", ret
);
10812 * Build time assertion that we keep the data_head at the intended
10813 * location. IOW, validation we got the __reserved[] size right.
10815 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page
, data_head
))
10819 ssize_t
perf_event_sysfs_show(struct device
*dev
, struct device_attribute
*attr
,
10822 struct perf_pmu_events_attr
*pmu_attr
=
10823 container_of(attr
, struct perf_pmu_events_attr
, attr
);
10825 if (pmu_attr
->event_str
)
10826 return sprintf(page
, "%s\n", pmu_attr
->event_str
);
10830 EXPORT_SYMBOL_GPL(perf_event_sysfs_show
);
10832 static int __init
perf_event_sysfs_init(void)
10837 mutex_lock(&pmus_lock
);
10839 ret
= bus_register(&pmu_bus
);
10843 list_for_each_entry(pmu
, &pmus
, entry
) {
10844 if (!pmu
->name
|| pmu
->type
< 0)
10847 ret
= pmu_dev_alloc(pmu
);
10848 WARN(ret
, "Failed to register pmu: %s, reason %d\n", pmu
->name
, ret
);
10850 pmu_bus_running
= 1;
10854 mutex_unlock(&pmus_lock
);
10858 device_initcall(perf_event_sysfs_init
);
10860 #ifdef CONFIG_CGROUP_PERF
10861 static struct cgroup_subsys_state
*
10862 perf_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
10864 struct perf_cgroup
*jc
;
10866 jc
= kzalloc(sizeof(*jc
), GFP_KERNEL
);
10868 return ERR_PTR(-ENOMEM
);
10870 jc
->info
= alloc_percpu(struct perf_cgroup_info
);
10873 return ERR_PTR(-ENOMEM
);
10879 static void perf_cgroup_css_free(struct cgroup_subsys_state
*css
)
10881 struct perf_cgroup
*jc
= container_of(css
, struct perf_cgroup
, css
);
10883 free_percpu(jc
->info
);
10887 static int __perf_cgroup_move(void *info
)
10889 struct task_struct
*task
= info
;
10891 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
| PERF_CGROUP_SWIN
);
10896 static void perf_cgroup_attach(struct cgroup_taskset
*tset
)
10898 struct task_struct
*task
;
10899 struct cgroup_subsys_state
*css
;
10901 cgroup_taskset_for_each(task
, css
, tset
)
10902 task_function_call(task
, __perf_cgroup_move
, task
);
10905 struct cgroup_subsys perf_event_cgrp_subsys
= {
10906 .css_alloc
= perf_cgroup_css_alloc
,
10907 .css_free
= perf_cgroup_css_free
,
10908 .attach
= perf_cgroup_attach
,
10910 #endif /* CONFIG_CGROUP_PERF */