2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/idr.h>
17 #include <linux/file.h>
18 #include <linux/poll.h>
19 #include <linux/slab.h>
20 #include <linux/hash.h>
21 #include <linux/tick.h>
22 #include <linux/sysfs.h>
23 #include <linux/dcache.h>
24 #include <linux/percpu.h>
25 #include <linux/ptrace.h>
26 #include <linux/reboot.h>
27 #include <linux/vmstat.h>
28 #include <linux/device.h>
29 #include <linux/export.h>
30 #include <linux/vmalloc.h>
31 #include <linux/hardirq.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/cgroup.h>
38 #include <linux/perf_event.h>
39 #include <linux/trace_events.h>
40 #include <linux/hw_breakpoint.h>
41 #include <linux/mm_types.h>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
45 #include <linux/bpf.h>
46 #include <linux/filter.h>
47 #include <linux/namei.h>
48 #include <linux/parser.h>
49 #include <linux/sched/clock.h>
50 #include <linux/sched/mm.h>
51 #include <linux/proc_ns.h>
52 #include <linux/mount.h>
56 #include <asm/irq_regs.h>
58 typedef int (*remote_function_f
)(void *);
60 struct remote_function_call
{
61 struct task_struct
*p
;
62 remote_function_f func
;
67 static void remote_function(void *data
)
69 struct remote_function_call
*tfc
= data
;
70 struct task_struct
*p
= tfc
->p
;
74 if (task_cpu(p
) != smp_processor_id())
78 * Now that we're on right CPU with IRQs disabled, we can test
79 * if we hit the right task without races.
82 tfc
->ret
= -ESRCH
; /* No such (running) process */
87 tfc
->ret
= tfc
->func(tfc
->info
);
91 * task_function_call - call a function on the cpu on which a task runs
92 * @p: the task to evaluate
93 * @func: the function to be called
94 * @info: the function call argument
96 * Calls the function @func when the task is currently running. This might
97 * be on the current CPU, which just calls the function directly
99 * returns: @func return value, or
100 * -ESRCH - when the process isn't running
101 * -EAGAIN - when the process moved away
104 task_function_call(struct task_struct
*p
, remote_function_f func
, void *info
)
106 struct remote_function_call data
= {
115 ret
= smp_call_function_single(task_cpu(p
), remote_function
, &data
, 1);
118 } while (ret
== -EAGAIN
);
124 * cpu_function_call - call a function on the cpu
125 * @func: the function to be called
126 * @info: the function call argument
128 * Calls the function @func on the remote cpu.
130 * returns: @func return value or -ENXIO when the cpu is offline
132 static int cpu_function_call(int cpu
, remote_function_f func
, void *info
)
134 struct remote_function_call data
= {
138 .ret
= -ENXIO
, /* No such CPU */
141 smp_call_function_single(cpu
, remote_function
, &data
, 1);
146 static inline struct perf_cpu_context
*
147 __get_cpu_context(struct perf_event_context
*ctx
)
149 return this_cpu_ptr(ctx
->pmu
->pmu_cpu_context
);
152 static void perf_ctx_lock(struct perf_cpu_context
*cpuctx
,
153 struct perf_event_context
*ctx
)
155 raw_spin_lock(&cpuctx
->ctx
.lock
);
157 raw_spin_lock(&ctx
->lock
);
160 static void perf_ctx_unlock(struct perf_cpu_context
*cpuctx
,
161 struct perf_event_context
*ctx
)
164 raw_spin_unlock(&ctx
->lock
);
165 raw_spin_unlock(&cpuctx
->ctx
.lock
);
168 #define TASK_TOMBSTONE ((void *)-1L)
170 static bool is_kernel_event(struct perf_event
*event
)
172 return READ_ONCE(event
->owner
) == TASK_TOMBSTONE
;
176 * On task ctx scheduling...
178 * When !ctx->nr_events a task context will not be scheduled. This means
179 * we can disable the scheduler hooks (for performance) without leaving
180 * pending task ctx state.
182 * This however results in two special cases:
184 * - removing the last event from a task ctx; this is relatively straight
185 * forward and is done in __perf_remove_from_context.
187 * - adding the first event to a task ctx; this is tricky because we cannot
188 * rely on ctx->is_active and therefore cannot use event_function_call().
189 * See perf_install_in_context().
191 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
194 typedef void (*event_f
)(struct perf_event
*, struct perf_cpu_context
*,
195 struct perf_event_context
*, void *);
197 struct event_function_struct
{
198 struct perf_event
*event
;
203 static int event_function(void *info
)
205 struct event_function_struct
*efs
= info
;
206 struct perf_event
*event
= efs
->event
;
207 struct perf_event_context
*ctx
= event
->ctx
;
208 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
209 struct perf_event_context
*task_ctx
= cpuctx
->task_ctx
;
212 WARN_ON_ONCE(!irqs_disabled());
214 perf_ctx_lock(cpuctx
, task_ctx
);
216 * Since we do the IPI call without holding ctx->lock things can have
217 * changed, double check we hit the task we set out to hit.
220 if (ctx
->task
!= current
) {
226 * We only use event_function_call() on established contexts,
227 * and event_function() is only ever called when active (or
228 * rather, we'll have bailed in task_function_call() or the
229 * above ctx->task != current test), therefore we must have
230 * ctx->is_active here.
232 WARN_ON_ONCE(!ctx
->is_active
);
234 * And since we have ctx->is_active, cpuctx->task_ctx must
237 WARN_ON_ONCE(task_ctx
!= ctx
);
239 WARN_ON_ONCE(&cpuctx
->ctx
!= ctx
);
242 efs
->func(event
, cpuctx
, ctx
, efs
->data
);
244 perf_ctx_unlock(cpuctx
, task_ctx
);
249 static void event_function_call(struct perf_event
*event
, event_f func
, void *data
)
251 struct perf_event_context
*ctx
= event
->ctx
;
252 struct task_struct
*task
= READ_ONCE(ctx
->task
); /* verified in event_function */
253 struct event_function_struct efs
= {
259 if (!event
->parent
) {
261 * If this is a !child event, we must hold ctx::mutex to
262 * stabilize the the event->ctx relation. See
263 * perf_event_ctx_lock().
265 lockdep_assert_held(&ctx
->mutex
);
269 cpu_function_call(event
->cpu
, event_function
, &efs
);
273 if (task
== TASK_TOMBSTONE
)
277 if (!task_function_call(task
, event_function
, &efs
))
280 raw_spin_lock_irq(&ctx
->lock
);
282 * Reload the task pointer, it might have been changed by
283 * a concurrent perf_event_context_sched_out().
286 if (task
== TASK_TOMBSTONE
) {
287 raw_spin_unlock_irq(&ctx
->lock
);
290 if (ctx
->is_active
) {
291 raw_spin_unlock_irq(&ctx
->lock
);
294 func(event
, NULL
, ctx
, data
);
295 raw_spin_unlock_irq(&ctx
->lock
);
299 * Similar to event_function_call() + event_function(), but hard assumes IRQs
300 * are already disabled and we're on the right CPU.
302 static void event_function_local(struct perf_event
*event
, event_f func
, void *data
)
304 struct perf_event_context
*ctx
= event
->ctx
;
305 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
306 struct task_struct
*task
= READ_ONCE(ctx
->task
);
307 struct perf_event_context
*task_ctx
= NULL
;
309 WARN_ON_ONCE(!irqs_disabled());
312 if (task
== TASK_TOMBSTONE
)
318 perf_ctx_lock(cpuctx
, task_ctx
);
321 if (task
== TASK_TOMBSTONE
)
326 * We must be either inactive or active and the right task,
327 * otherwise we're screwed, since we cannot IPI to somewhere
330 if (ctx
->is_active
) {
331 if (WARN_ON_ONCE(task
!= current
))
334 if (WARN_ON_ONCE(cpuctx
->task_ctx
!= ctx
))
338 WARN_ON_ONCE(&cpuctx
->ctx
!= ctx
);
341 func(event
, cpuctx
, ctx
, data
);
343 perf_ctx_unlock(cpuctx
, task_ctx
);
346 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
347 PERF_FLAG_FD_OUTPUT |\
348 PERF_FLAG_PID_CGROUP |\
349 PERF_FLAG_FD_CLOEXEC)
352 * branch priv levels that need permission checks
354 #define PERF_SAMPLE_BRANCH_PERM_PLM \
355 (PERF_SAMPLE_BRANCH_KERNEL |\
356 PERF_SAMPLE_BRANCH_HV)
359 EVENT_FLEXIBLE
= 0x1,
362 /* see ctx_resched() for details */
364 EVENT_ALL
= EVENT_FLEXIBLE
| EVENT_PINNED
,
368 * perf_sched_events : >0 events exist
369 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
372 static void perf_sched_delayed(struct work_struct
*work
);
373 DEFINE_STATIC_KEY_FALSE(perf_sched_events
);
374 static DECLARE_DELAYED_WORK(perf_sched_work
, perf_sched_delayed
);
375 static DEFINE_MUTEX(perf_sched_mutex
);
376 static atomic_t perf_sched_count
;
378 static DEFINE_PER_CPU(atomic_t
, perf_cgroup_events
);
379 static DEFINE_PER_CPU(int, perf_sched_cb_usages
);
380 static DEFINE_PER_CPU(struct pmu_event_list
, pmu_sb_events
);
382 static atomic_t nr_mmap_events __read_mostly
;
383 static atomic_t nr_comm_events __read_mostly
;
384 static atomic_t nr_namespaces_events __read_mostly
;
385 static atomic_t nr_task_events __read_mostly
;
386 static atomic_t nr_freq_events __read_mostly
;
387 static atomic_t nr_switch_events __read_mostly
;
389 static LIST_HEAD(pmus
);
390 static DEFINE_MUTEX(pmus_lock
);
391 static struct srcu_struct pmus_srcu
;
392 static cpumask_var_t perf_online_mask
;
395 * perf event paranoia level:
396 * -1 - not paranoid at all
397 * 0 - disallow raw tracepoint access for unpriv
398 * 1 - disallow cpu events for unpriv
399 * 2 - disallow kernel profiling for unpriv
401 int sysctl_perf_event_paranoid __read_mostly
= 2;
403 /* Minimum for 512 kiB + 1 user control page */
404 int sysctl_perf_event_mlock __read_mostly
= 512 + (PAGE_SIZE
/ 1024); /* 'free' kiB per user */
407 * max perf event sample rate
409 #define DEFAULT_MAX_SAMPLE_RATE 100000
410 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
411 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
413 int sysctl_perf_event_sample_rate __read_mostly
= DEFAULT_MAX_SAMPLE_RATE
;
415 static int max_samples_per_tick __read_mostly
= DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE
, HZ
);
416 static int perf_sample_period_ns __read_mostly
= DEFAULT_SAMPLE_PERIOD_NS
;
418 static int perf_sample_allowed_ns __read_mostly
=
419 DEFAULT_SAMPLE_PERIOD_NS
* DEFAULT_CPU_TIME_MAX_PERCENT
/ 100;
421 static void update_perf_cpu_limits(void)
423 u64 tmp
= perf_sample_period_ns
;
425 tmp
*= sysctl_perf_cpu_time_max_percent
;
426 tmp
= div_u64(tmp
, 100);
430 WRITE_ONCE(perf_sample_allowed_ns
, tmp
);
433 static int perf_rotate_context(struct perf_cpu_context
*cpuctx
);
435 int perf_proc_update_handler(struct ctl_table
*table
, int write
,
436 void __user
*buffer
, size_t *lenp
,
439 int ret
= proc_dointvec_minmax(table
, write
, buffer
, lenp
, ppos
);
445 * If throttling is disabled don't allow the write:
447 if (sysctl_perf_cpu_time_max_percent
== 100 ||
448 sysctl_perf_cpu_time_max_percent
== 0)
451 max_samples_per_tick
= DIV_ROUND_UP(sysctl_perf_event_sample_rate
, HZ
);
452 perf_sample_period_ns
= NSEC_PER_SEC
/ sysctl_perf_event_sample_rate
;
453 update_perf_cpu_limits();
458 int sysctl_perf_cpu_time_max_percent __read_mostly
= DEFAULT_CPU_TIME_MAX_PERCENT
;
460 int perf_cpu_time_max_percent_handler(struct ctl_table
*table
, int write
,
461 void __user
*buffer
, size_t *lenp
,
464 int ret
= proc_dointvec_minmax(table
, write
, buffer
, lenp
, ppos
);
469 if (sysctl_perf_cpu_time_max_percent
== 100 ||
470 sysctl_perf_cpu_time_max_percent
== 0) {
472 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
473 WRITE_ONCE(perf_sample_allowed_ns
, 0);
475 update_perf_cpu_limits();
482 * perf samples are done in some very critical code paths (NMIs).
483 * If they take too much CPU time, the system can lock up and not
484 * get any real work done. This will drop the sample rate when
485 * we detect that events are taking too long.
487 #define NR_ACCUMULATED_SAMPLES 128
488 static DEFINE_PER_CPU(u64
, running_sample_length
);
490 static u64 __report_avg
;
491 static u64 __report_allowed
;
493 static void perf_duration_warn(struct irq_work
*w
)
495 printk_ratelimited(KERN_INFO
496 "perf: interrupt took too long (%lld > %lld), lowering "
497 "kernel.perf_event_max_sample_rate to %d\n",
498 __report_avg
, __report_allowed
,
499 sysctl_perf_event_sample_rate
);
502 static DEFINE_IRQ_WORK(perf_duration_work
, perf_duration_warn
);
504 void perf_sample_event_took(u64 sample_len_ns
)
506 u64 max_len
= READ_ONCE(perf_sample_allowed_ns
);
514 /* Decay the counter by 1 average sample. */
515 running_len
= __this_cpu_read(running_sample_length
);
516 running_len
-= running_len
/NR_ACCUMULATED_SAMPLES
;
517 running_len
+= sample_len_ns
;
518 __this_cpu_write(running_sample_length
, running_len
);
521 * Note: this will be biased artifically low until we have
522 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
523 * from having to maintain a count.
525 avg_len
= running_len
/NR_ACCUMULATED_SAMPLES
;
526 if (avg_len
<= max_len
)
529 __report_avg
= avg_len
;
530 __report_allowed
= max_len
;
533 * Compute a throttle threshold 25% below the current duration.
535 avg_len
+= avg_len
/ 4;
536 max
= (TICK_NSEC
/ 100) * sysctl_perf_cpu_time_max_percent
;
542 WRITE_ONCE(perf_sample_allowed_ns
, avg_len
);
543 WRITE_ONCE(max_samples_per_tick
, max
);
545 sysctl_perf_event_sample_rate
= max
* HZ
;
546 perf_sample_period_ns
= NSEC_PER_SEC
/ sysctl_perf_event_sample_rate
;
548 if (!irq_work_queue(&perf_duration_work
)) {
549 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
550 "kernel.perf_event_max_sample_rate to %d\n",
551 __report_avg
, __report_allowed
,
552 sysctl_perf_event_sample_rate
);
556 static atomic64_t perf_event_id
;
558 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
559 enum event_type_t event_type
);
561 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
562 enum event_type_t event_type
,
563 struct task_struct
*task
);
565 static void update_context_time(struct perf_event_context
*ctx
);
566 static u64
perf_event_time(struct perf_event
*event
);
568 void __weak
perf_event_print_debug(void) { }
570 extern __weak
const char *perf_pmu_name(void)
575 static inline u64
perf_clock(void)
577 return local_clock();
580 static inline u64
perf_event_clock(struct perf_event
*event
)
582 return event
->clock();
585 #ifdef CONFIG_CGROUP_PERF
588 perf_cgroup_match(struct perf_event
*event
)
590 struct perf_event_context
*ctx
= event
->ctx
;
591 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
593 /* @event doesn't care about cgroup */
597 /* wants specific cgroup scope but @cpuctx isn't associated with any */
602 * Cgroup scoping is recursive. An event enabled for a cgroup is
603 * also enabled for all its descendant cgroups. If @cpuctx's
604 * cgroup is a descendant of @event's (the test covers identity
605 * case), it's a match.
607 return cgroup_is_descendant(cpuctx
->cgrp
->css
.cgroup
,
608 event
->cgrp
->css
.cgroup
);
611 static inline void perf_detach_cgroup(struct perf_event
*event
)
613 css_put(&event
->cgrp
->css
);
617 static inline int is_cgroup_event(struct perf_event
*event
)
619 return event
->cgrp
!= NULL
;
622 static inline u64
perf_cgroup_event_time(struct perf_event
*event
)
624 struct perf_cgroup_info
*t
;
626 t
= per_cpu_ptr(event
->cgrp
->info
, event
->cpu
);
630 static inline void __update_cgrp_time(struct perf_cgroup
*cgrp
)
632 struct perf_cgroup_info
*info
;
637 info
= this_cpu_ptr(cgrp
->info
);
639 info
->time
+= now
- info
->timestamp
;
640 info
->timestamp
= now
;
643 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context
*cpuctx
)
645 struct perf_cgroup
*cgrp_out
= cpuctx
->cgrp
;
647 __update_cgrp_time(cgrp_out
);
650 static inline void update_cgrp_time_from_event(struct perf_event
*event
)
652 struct perf_cgroup
*cgrp
;
655 * ensure we access cgroup data only when needed and
656 * when we know the cgroup is pinned (css_get)
658 if (!is_cgroup_event(event
))
661 cgrp
= perf_cgroup_from_task(current
, event
->ctx
);
663 * Do not update time when cgroup is not active
665 if (cgroup_is_descendant(cgrp
->css
.cgroup
, event
->cgrp
->css
.cgroup
))
666 __update_cgrp_time(event
->cgrp
);
670 perf_cgroup_set_timestamp(struct task_struct
*task
,
671 struct perf_event_context
*ctx
)
673 struct perf_cgroup
*cgrp
;
674 struct perf_cgroup_info
*info
;
677 * ctx->lock held by caller
678 * ensure we do not access cgroup data
679 * unless we have the cgroup pinned (css_get)
681 if (!task
|| !ctx
->nr_cgroups
)
684 cgrp
= perf_cgroup_from_task(task
, ctx
);
685 info
= this_cpu_ptr(cgrp
->info
);
686 info
->timestamp
= ctx
->timestamp
;
689 static DEFINE_PER_CPU(struct list_head
, cgrp_cpuctx_list
);
691 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
692 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
695 * reschedule events based on the cgroup constraint of task.
697 * mode SWOUT : schedule out everything
698 * mode SWIN : schedule in based on cgroup for next
700 static void perf_cgroup_switch(struct task_struct
*task
, int mode
)
702 struct perf_cpu_context
*cpuctx
;
703 struct list_head
*list
;
707 * Disable interrupts and preemption to avoid this CPU's
708 * cgrp_cpuctx_entry to change under us.
710 local_irq_save(flags
);
712 list
= this_cpu_ptr(&cgrp_cpuctx_list
);
713 list_for_each_entry(cpuctx
, list
, cgrp_cpuctx_entry
) {
714 WARN_ON_ONCE(cpuctx
->ctx
.nr_cgroups
== 0);
716 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
717 perf_pmu_disable(cpuctx
->ctx
.pmu
);
719 if (mode
& PERF_CGROUP_SWOUT
) {
720 cpu_ctx_sched_out(cpuctx
, EVENT_ALL
);
722 * must not be done before ctxswout due
723 * to event_filter_match() in event_sched_out()
728 if (mode
& PERF_CGROUP_SWIN
) {
729 WARN_ON_ONCE(cpuctx
->cgrp
);
731 * set cgrp before ctxsw in to allow
732 * event_filter_match() to not have to pass
734 * we pass the cpuctx->ctx to perf_cgroup_from_task()
735 * because cgorup events are only per-cpu
737 cpuctx
->cgrp
= perf_cgroup_from_task(task
,
739 cpu_ctx_sched_in(cpuctx
, EVENT_ALL
, task
);
741 perf_pmu_enable(cpuctx
->ctx
.pmu
);
742 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
745 local_irq_restore(flags
);
748 static inline void perf_cgroup_sched_out(struct task_struct
*task
,
749 struct task_struct
*next
)
751 struct perf_cgroup
*cgrp1
;
752 struct perf_cgroup
*cgrp2
= NULL
;
756 * we come here when we know perf_cgroup_events > 0
757 * we do not need to pass the ctx here because we know
758 * we are holding the rcu lock
760 cgrp1
= perf_cgroup_from_task(task
, NULL
);
761 cgrp2
= perf_cgroup_from_task(next
, NULL
);
764 * only schedule out current cgroup events if we know
765 * that we are switching to a different cgroup. Otherwise,
766 * do no touch the cgroup events.
769 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
);
774 static inline void perf_cgroup_sched_in(struct task_struct
*prev
,
775 struct task_struct
*task
)
777 struct perf_cgroup
*cgrp1
;
778 struct perf_cgroup
*cgrp2
= NULL
;
782 * we come here when we know perf_cgroup_events > 0
783 * we do not need to pass the ctx here because we know
784 * we are holding the rcu lock
786 cgrp1
= perf_cgroup_from_task(task
, NULL
);
787 cgrp2
= perf_cgroup_from_task(prev
, NULL
);
790 * only need to schedule in cgroup events if we are changing
791 * cgroup during ctxsw. Cgroup events were not scheduled
792 * out of ctxsw out if that was not the case.
795 perf_cgroup_switch(task
, PERF_CGROUP_SWIN
);
800 static inline int perf_cgroup_connect(int fd
, struct perf_event
*event
,
801 struct perf_event_attr
*attr
,
802 struct perf_event
*group_leader
)
804 struct perf_cgroup
*cgrp
;
805 struct cgroup_subsys_state
*css
;
806 struct fd f
= fdget(fd
);
812 css
= css_tryget_online_from_dir(f
.file
->f_path
.dentry
,
813 &perf_event_cgrp_subsys
);
819 cgrp
= container_of(css
, struct perf_cgroup
, css
);
823 * all events in a group must monitor
824 * the same cgroup because a task belongs
825 * to only one perf cgroup at a time
827 if (group_leader
&& group_leader
->cgrp
!= cgrp
) {
828 perf_detach_cgroup(event
);
837 perf_cgroup_set_shadow_time(struct perf_event
*event
, u64 now
)
839 struct perf_cgroup_info
*t
;
840 t
= per_cpu_ptr(event
->cgrp
->info
, event
->cpu
);
841 event
->shadow_ctx_time
= now
- t
->timestamp
;
845 perf_cgroup_defer_enabled(struct perf_event
*event
)
848 * when the current task's perf cgroup does not match
849 * the event's, we need to remember to call the
850 * perf_mark_enable() function the first time a task with
851 * a matching perf cgroup is scheduled in.
853 if (is_cgroup_event(event
) && !perf_cgroup_match(event
))
854 event
->cgrp_defer_enabled
= 1;
858 perf_cgroup_mark_enabled(struct perf_event
*event
,
859 struct perf_event_context
*ctx
)
861 struct perf_event
*sub
;
862 u64 tstamp
= perf_event_time(event
);
864 if (!event
->cgrp_defer_enabled
)
867 event
->cgrp_defer_enabled
= 0;
869 event
->tstamp_enabled
= tstamp
- event
->total_time_enabled
;
870 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
871 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
) {
872 sub
->tstamp_enabled
= tstamp
- sub
->total_time_enabled
;
873 sub
->cgrp_defer_enabled
= 0;
879 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
880 * cleared when last cgroup event is removed.
883 list_update_cgroup_event(struct perf_event
*event
,
884 struct perf_event_context
*ctx
, bool add
)
886 struct perf_cpu_context
*cpuctx
;
887 struct list_head
*cpuctx_entry
;
889 if (!is_cgroup_event(event
))
892 if (add
&& ctx
->nr_cgroups
++)
894 else if (!add
&& --ctx
->nr_cgroups
)
897 * Because cgroup events are always per-cpu events,
898 * this will always be called from the right CPU.
900 cpuctx
= __get_cpu_context(ctx
);
901 cpuctx_entry
= &cpuctx
->cgrp_cpuctx_entry
;
902 /* cpuctx->cgrp is NULL unless a cgroup event is active in this CPU .*/
904 struct perf_cgroup
*cgrp
= perf_cgroup_from_task(current
, ctx
);
906 list_add(cpuctx_entry
, this_cpu_ptr(&cgrp_cpuctx_list
));
907 if (cgroup_is_descendant(cgrp
->css
.cgroup
, event
->cgrp
->css
.cgroup
))
910 list_del(cpuctx_entry
);
915 #else /* !CONFIG_CGROUP_PERF */
918 perf_cgroup_match(struct perf_event
*event
)
923 static inline void perf_detach_cgroup(struct perf_event
*event
)
926 static inline int is_cgroup_event(struct perf_event
*event
)
931 static inline void update_cgrp_time_from_event(struct perf_event
*event
)
935 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context
*cpuctx
)
939 static inline void perf_cgroup_sched_out(struct task_struct
*task
,
940 struct task_struct
*next
)
944 static inline void perf_cgroup_sched_in(struct task_struct
*prev
,
945 struct task_struct
*task
)
949 static inline int perf_cgroup_connect(pid_t pid
, struct perf_event
*event
,
950 struct perf_event_attr
*attr
,
951 struct perf_event
*group_leader
)
957 perf_cgroup_set_timestamp(struct task_struct
*task
,
958 struct perf_event_context
*ctx
)
963 perf_cgroup_switch(struct task_struct
*task
, struct task_struct
*next
)
968 perf_cgroup_set_shadow_time(struct perf_event
*event
, u64 now
)
972 static inline u64
perf_cgroup_event_time(struct perf_event
*event
)
978 perf_cgroup_defer_enabled(struct perf_event
*event
)
983 perf_cgroup_mark_enabled(struct perf_event
*event
,
984 struct perf_event_context
*ctx
)
989 list_update_cgroup_event(struct perf_event
*event
,
990 struct perf_event_context
*ctx
, bool add
)
997 * set default to be dependent on timer tick just
1000 #define PERF_CPU_HRTIMER (1000 / HZ)
1002 * function must be called with interrupts disabled
1004 static enum hrtimer_restart
perf_mux_hrtimer_handler(struct hrtimer
*hr
)
1006 struct perf_cpu_context
*cpuctx
;
1009 WARN_ON(!irqs_disabled());
1011 cpuctx
= container_of(hr
, struct perf_cpu_context
, hrtimer
);
1012 rotations
= perf_rotate_context(cpuctx
);
1014 raw_spin_lock(&cpuctx
->hrtimer_lock
);
1016 hrtimer_forward_now(hr
, cpuctx
->hrtimer_interval
);
1018 cpuctx
->hrtimer_active
= 0;
1019 raw_spin_unlock(&cpuctx
->hrtimer_lock
);
1021 return rotations
? HRTIMER_RESTART
: HRTIMER_NORESTART
;
1024 static void __perf_mux_hrtimer_init(struct perf_cpu_context
*cpuctx
, int cpu
)
1026 struct hrtimer
*timer
= &cpuctx
->hrtimer
;
1027 struct pmu
*pmu
= cpuctx
->ctx
.pmu
;
1030 /* no multiplexing needed for SW PMU */
1031 if (pmu
->task_ctx_nr
== perf_sw_context
)
1035 * check default is sane, if not set then force to
1036 * default interval (1/tick)
1038 interval
= pmu
->hrtimer_interval_ms
;
1040 interval
= pmu
->hrtimer_interval_ms
= PERF_CPU_HRTIMER
;
1042 cpuctx
->hrtimer_interval
= ns_to_ktime(NSEC_PER_MSEC
* interval
);
1044 raw_spin_lock_init(&cpuctx
->hrtimer_lock
);
1045 hrtimer_init(timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_ABS_PINNED
);
1046 timer
->function
= perf_mux_hrtimer_handler
;
1049 static int perf_mux_hrtimer_restart(struct perf_cpu_context
*cpuctx
)
1051 struct hrtimer
*timer
= &cpuctx
->hrtimer
;
1052 struct pmu
*pmu
= cpuctx
->ctx
.pmu
;
1053 unsigned long flags
;
1055 /* not for SW PMU */
1056 if (pmu
->task_ctx_nr
== perf_sw_context
)
1059 raw_spin_lock_irqsave(&cpuctx
->hrtimer_lock
, flags
);
1060 if (!cpuctx
->hrtimer_active
) {
1061 cpuctx
->hrtimer_active
= 1;
1062 hrtimer_forward_now(timer
, cpuctx
->hrtimer_interval
);
1063 hrtimer_start_expires(timer
, HRTIMER_MODE_ABS_PINNED
);
1065 raw_spin_unlock_irqrestore(&cpuctx
->hrtimer_lock
, flags
);
1070 void perf_pmu_disable(struct pmu
*pmu
)
1072 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
1074 pmu
->pmu_disable(pmu
);
1077 void perf_pmu_enable(struct pmu
*pmu
)
1079 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
1081 pmu
->pmu_enable(pmu
);
1084 static DEFINE_PER_CPU(struct list_head
, active_ctx_list
);
1087 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1088 * perf_event_task_tick() are fully serialized because they're strictly cpu
1089 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1090 * disabled, while perf_event_task_tick is called from IRQ context.
1092 static void perf_event_ctx_activate(struct perf_event_context
*ctx
)
1094 struct list_head
*head
= this_cpu_ptr(&active_ctx_list
);
1096 WARN_ON(!irqs_disabled());
1098 WARN_ON(!list_empty(&ctx
->active_ctx_list
));
1100 list_add(&ctx
->active_ctx_list
, head
);
1103 static void perf_event_ctx_deactivate(struct perf_event_context
*ctx
)
1105 WARN_ON(!irqs_disabled());
1107 WARN_ON(list_empty(&ctx
->active_ctx_list
));
1109 list_del_init(&ctx
->active_ctx_list
);
1112 static void get_ctx(struct perf_event_context
*ctx
)
1114 WARN_ON(!atomic_inc_not_zero(&ctx
->refcount
));
1117 static void free_ctx(struct rcu_head
*head
)
1119 struct perf_event_context
*ctx
;
1121 ctx
= container_of(head
, struct perf_event_context
, rcu_head
);
1122 kfree(ctx
->task_ctx_data
);
1126 static void put_ctx(struct perf_event_context
*ctx
)
1128 if (atomic_dec_and_test(&ctx
->refcount
)) {
1129 if (ctx
->parent_ctx
)
1130 put_ctx(ctx
->parent_ctx
);
1131 if (ctx
->task
&& ctx
->task
!= TASK_TOMBSTONE
)
1132 put_task_struct(ctx
->task
);
1133 call_rcu(&ctx
->rcu_head
, free_ctx
);
1138 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1139 * perf_pmu_migrate_context() we need some magic.
1141 * Those places that change perf_event::ctx will hold both
1142 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1144 * Lock ordering is by mutex address. There are two other sites where
1145 * perf_event_context::mutex nests and those are:
1147 * - perf_event_exit_task_context() [ child , 0 ]
1148 * perf_event_exit_event()
1149 * put_event() [ parent, 1 ]
1151 * - perf_event_init_context() [ parent, 0 ]
1152 * inherit_task_group()
1155 * perf_event_alloc()
1157 * perf_try_init_event() [ child , 1 ]
1159 * While it appears there is an obvious deadlock here -- the parent and child
1160 * nesting levels are inverted between the two. This is in fact safe because
1161 * life-time rules separate them. That is an exiting task cannot fork, and a
1162 * spawning task cannot (yet) exit.
1164 * But remember that that these are parent<->child context relations, and
1165 * migration does not affect children, therefore these two orderings should not
1168 * The change in perf_event::ctx does not affect children (as claimed above)
1169 * because the sys_perf_event_open() case will install a new event and break
1170 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1171 * concerned with cpuctx and that doesn't have children.
1173 * The places that change perf_event::ctx will issue:
1175 * perf_remove_from_context();
1176 * synchronize_rcu();
1177 * perf_install_in_context();
1179 * to affect the change. The remove_from_context() + synchronize_rcu() should
1180 * quiesce the event, after which we can install it in the new location. This
1181 * means that only external vectors (perf_fops, prctl) can perturb the event
1182 * while in transit. Therefore all such accessors should also acquire
1183 * perf_event_context::mutex to serialize against this.
1185 * However; because event->ctx can change while we're waiting to acquire
1186 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1191 * task_struct::perf_event_mutex
1192 * perf_event_context::mutex
1193 * perf_event::child_mutex;
1194 * perf_event_context::lock
1195 * perf_event::mmap_mutex
1198 static struct perf_event_context
*
1199 perf_event_ctx_lock_nested(struct perf_event
*event
, int nesting
)
1201 struct perf_event_context
*ctx
;
1205 ctx
= ACCESS_ONCE(event
->ctx
);
1206 if (!atomic_inc_not_zero(&ctx
->refcount
)) {
1212 mutex_lock_nested(&ctx
->mutex
, nesting
);
1213 if (event
->ctx
!= ctx
) {
1214 mutex_unlock(&ctx
->mutex
);
1222 static inline struct perf_event_context
*
1223 perf_event_ctx_lock(struct perf_event
*event
)
1225 return perf_event_ctx_lock_nested(event
, 0);
1228 static void perf_event_ctx_unlock(struct perf_event
*event
,
1229 struct perf_event_context
*ctx
)
1231 mutex_unlock(&ctx
->mutex
);
1236 * This must be done under the ctx->lock, such as to serialize against
1237 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1238 * calling scheduler related locks and ctx->lock nests inside those.
1240 static __must_check
struct perf_event_context
*
1241 unclone_ctx(struct perf_event_context
*ctx
)
1243 struct perf_event_context
*parent_ctx
= ctx
->parent_ctx
;
1245 lockdep_assert_held(&ctx
->lock
);
1248 ctx
->parent_ctx
= NULL
;
1254 static u32
perf_event_pid_type(struct perf_event
*event
, struct task_struct
*p
,
1259 * only top level events have the pid namespace they were created in
1262 event
= event
->parent
;
1264 nr
= __task_pid_nr_ns(p
, type
, event
->ns
);
1265 /* avoid -1 if it is idle thread or runs in another ns */
1266 if (!nr
&& !pid_alive(p
))
1271 static u32
perf_event_pid(struct perf_event
*event
, struct task_struct
*p
)
1273 return perf_event_pid_type(event
, p
, __PIDTYPE_TGID
);
1276 static u32
perf_event_tid(struct perf_event
*event
, struct task_struct
*p
)
1278 return perf_event_pid_type(event
, p
, PIDTYPE_PID
);
1282 * If we inherit events we want to return the parent event id
1285 static u64
primary_event_id(struct perf_event
*event
)
1290 id
= event
->parent
->id
;
1296 * Get the perf_event_context for a task and lock it.
1298 * This has to cope with with the fact that until it is locked,
1299 * the context could get moved to another task.
1301 static struct perf_event_context
*
1302 perf_lock_task_context(struct task_struct
*task
, int ctxn
, unsigned long *flags
)
1304 struct perf_event_context
*ctx
;
1308 * One of the few rules of preemptible RCU is that one cannot do
1309 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1310 * part of the read side critical section was irqs-enabled -- see
1311 * rcu_read_unlock_special().
1313 * Since ctx->lock nests under rq->lock we must ensure the entire read
1314 * side critical section has interrupts disabled.
1316 local_irq_save(*flags
);
1318 ctx
= rcu_dereference(task
->perf_event_ctxp
[ctxn
]);
1321 * If this context is a clone of another, it might
1322 * get swapped for another underneath us by
1323 * perf_event_task_sched_out, though the
1324 * rcu_read_lock() protects us from any context
1325 * getting freed. Lock the context and check if it
1326 * got swapped before we could get the lock, and retry
1327 * if so. If we locked the right context, then it
1328 * can't get swapped on us any more.
1330 raw_spin_lock(&ctx
->lock
);
1331 if (ctx
!= rcu_dereference(task
->perf_event_ctxp
[ctxn
])) {
1332 raw_spin_unlock(&ctx
->lock
);
1334 local_irq_restore(*flags
);
1338 if (ctx
->task
== TASK_TOMBSTONE
||
1339 !atomic_inc_not_zero(&ctx
->refcount
)) {
1340 raw_spin_unlock(&ctx
->lock
);
1343 WARN_ON_ONCE(ctx
->task
!= task
);
1348 local_irq_restore(*flags
);
1353 * Get the context for a task and increment its pin_count so it
1354 * can't get swapped to another task. This also increments its
1355 * reference count so that the context can't get freed.
1357 static struct perf_event_context
*
1358 perf_pin_task_context(struct task_struct
*task
, int ctxn
)
1360 struct perf_event_context
*ctx
;
1361 unsigned long flags
;
1363 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
1366 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1371 static void perf_unpin_context(struct perf_event_context
*ctx
)
1373 unsigned long flags
;
1375 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
1377 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1381 * Update the record of the current time in a context.
1383 static void update_context_time(struct perf_event_context
*ctx
)
1385 u64 now
= perf_clock();
1387 ctx
->time
+= now
- ctx
->timestamp
;
1388 ctx
->timestamp
= now
;
1391 static u64
perf_event_time(struct perf_event
*event
)
1393 struct perf_event_context
*ctx
= event
->ctx
;
1395 if (is_cgroup_event(event
))
1396 return perf_cgroup_event_time(event
);
1398 return ctx
? ctx
->time
: 0;
1402 * Update the total_time_enabled and total_time_running fields for a event.
1404 static void update_event_times(struct perf_event
*event
)
1406 struct perf_event_context
*ctx
= event
->ctx
;
1409 lockdep_assert_held(&ctx
->lock
);
1411 if (event
->state
< PERF_EVENT_STATE_INACTIVE
||
1412 event
->group_leader
->state
< PERF_EVENT_STATE_INACTIVE
)
1416 * in cgroup mode, time_enabled represents
1417 * the time the event was enabled AND active
1418 * tasks were in the monitored cgroup. This is
1419 * independent of the activity of the context as
1420 * there may be a mix of cgroup and non-cgroup events.
1422 * That is why we treat cgroup events differently
1425 if (is_cgroup_event(event
))
1426 run_end
= perf_cgroup_event_time(event
);
1427 else if (ctx
->is_active
)
1428 run_end
= ctx
->time
;
1430 run_end
= event
->tstamp_stopped
;
1432 event
->total_time_enabled
= run_end
- event
->tstamp_enabled
;
1434 if (event
->state
== PERF_EVENT_STATE_INACTIVE
)
1435 run_end
= event
->tstamp_stopped
;
1437 run_end
= perf_event_time(event
);
1439 event
->total_time_running
= run_end
- event
->tstamp_running
;
1444 * Update total_time_enabled and total_time_running for all events in a group.
1446 static void update_group_times(struct perf_event
*leader
)
1448 struct perf_event
*event
;
1450 update_event_times(leader
);
1451 list_for_each_entry(event
, &leader
->sibling_list
, group_entry
)
1452 update_event_times(event
);
1455 static enum event_type_t
get_event_type(struct perf_event
*event
)
1457 struct perf_event_context
*ctx
= event
->ctx
;
1458 enum event_type_t event_type
;
1460 lockdep_assert_held(&ctx
->lock
);
1463 * It's 'group type', really, because if our group leader is
1464 * pinned, so are we.
1466 if (event
->group_leader
!= event
)
1467 event
= event
->group_leader
;
1469 event_type
= event
->attr
.pinned
? EVENT_PINNED
: EVENT_FLEXIBLE
;
1471 event_type
|= EVENT_CPU
;
1476 static struct list_head
*
1477 ctx_group_list(struct perf_event
*event
, struct perf_event_context
*ctx
)
1479 if (event
->attr
.pinned
)
1480 return &ctx
->pinned_groups
;
1482 return &ctx
->flexible_groups
;
1486 * Add a event from the lists for its context.
1487 * Must be called with ctx->mutex and ctx->lock held.
1490 list_add_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
1492 lockdep_assert_held(&ctx
->lock
);
1494 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_CONTEXT
);
1495 event
->attach_state
|= PERF_ATTACH_CONTEXT
;
1498 * If we're a stand alone event or group leader, we go to the context
1499 * list, group events are kept attached to the group so that
1500 * perf_group_detach can, at all times, locate all siblings.
1502 if (event
->group_leader
== event
) {
1503 struct list_head
*list
;
1505 event
->group_caps
= event
->event_caps
;
1507 list
= ctx_group_list(event
, ctx
);
1508 list_add_tail(&event
->group_entry
, list
);
1511 list_update_cgroup_event(event
, ctx
, true);
1513 list_add_rcu(&event
->event_entry
, &ctx
->event_list
);
1515 if (event
->attr
.inherit_stat
)
1522 * Initialize event state based on the perf_event_attr::disabled.
1524 static inline void perf_event__state_init(struct perf_event
*event
)
1526 event
->state
= event
->attr
.disabled
? PERF_EVENT_STATE_OFF
:
1527 PERF_EVENT_STATE_INACTIVE
;
1530 static void __perf_event_read_size(struct perf_event
*event
, int nr_siblings
)
1532 int entry
= sizeof(u64
); /* value */
1536 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1537 size
+= sizeof(u64
);
1539 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1540 size
+= sizeof(u64
);
1542 if (event
->attr
.read_format
& PERF_FORMAT_ID
)
1543 entry
+= sizeof(u64
);
1545 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
) {
1547 size
+= sizeof(u64
);
1551 event
->read_size
= size
;
1554 static void __perf_event_header_size(struct perf_event
*event
, u64 sample_type
)
1556 struct perf_sample_data
*data
;
1559 if (sample_type
& PERF_SAMPLE_IP
)
1560 size
+= sizeof(data
->ip
);
1562 if (sample_type
& PERF_SAMPLE_ADDR
)
1563 size
+= sizeof(data
->addr
);
1565 if (sample_type
& PERF_SAMPLE_PERIOD
)
1566 size
+= sizeof(data
->period
);
1568 if (sample_type
& PERF_SAMPLE_WEIGHT
)
1569 size
+= sizeof(data
->weight
);
1571 if (sample_type
& PERF_SAMPLE_READ
)
1572 size
+= event
->read_size
;
1574 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
1575 size
+= sizeof(data
->data_src
.val
);
1577 if (sample_type
& PERF_SAMPLE_TRANSACTION
)
1578 size
+= sizeof(data
->txn
);
1580 if (sample_type
& PERF_SAMPLE_PHYS_ADDR
)
1581 size
+= sizeof(data
->phys_addr
);
1583 event
->header_size
= size
;
1587 * Called at perf_event creation and when events are attached/detached from a
1590 static void perf_event__header_size(struct perf_event
*event
)
1592 __perf_event_read_size(event
,
1593 event
->group_leader
->nr_siblings
);
1594 __perf_event_header_size(event
, event
->attr
.sample_type
);
1597 static void perf_event__id_header_size(struct perf_event
*event
)
1599 struct perf_sample_data
*data
;
1600 u64 sample_type
= event
->attr
.sample_type
;
1603 if (sample_type
& PERF_SAMPLE_TID
)
1604 size
+= sizeof(data
->tid_entry
);
1606 if (sample_type
& PERF_SAMPLE_TIME
)
1607 size
+= sizeof(data
->time
);
1609 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
1610 size
+= sizeof(data
->id
);
1612 if (sample_type
& PERF_SAMPLE_ID
)
1613 size
+= sizeof(data
->id
);
1615 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
1616 size
+= sizeof(data
->stream_id
);
1618 if (sample_type
& PERF_SAMPLE_CPU
)
1619 size
+= sizeof(data
->cpu_entry
);
1621 event
->id_header_size
= size
;
1624 static bool perf_event_validate_size(struct perf_event
*event
)
1627 * The values computed here will be over-written when we actually
1630 __perf_event_read_size(event
, event
->group_leader
->nr_siblings
+ 1);
1631 __perf_event_header_size(event
, event
->attr
.sample_type
& ~PERF_SAMPLE_READ
);
1632 perf_event__id_header_size(event
);
1635 * Sum the lot; should not exceed the 64k limit we have on records.
1636 * Conservative limit to allow for callchains and other variable fields.
1638 if (event
->read_size
+ event
->header_size
+
1639 event
->id_header_size
+ sizeof(struct perf_event_header
) >= 16*1024)
1645 static void perf_group_attach(struct perf_event
*event
)
1647 struct perf_event
*group_leader
= event
->group_leader
, *pos
;
1649 lockdep_assert_held(&event
->ctx
->lock
);
1652 * We can have double attach due to group movement in perf_event_open.
1654 if (event
->attach_state
& PERF_ATTACH_GROUP
)
1657 event
->attach_state
|= PERF_ATTACH_GROUP
;
1659 if (group_leader
== event
)
1662 WARN_ON_ONCE(group_leader
->ctx
!= event
->ctx
);
1664 group_leader
->group_caps
&= event
->event_caps
;
1666 list_add_tail(&event
->group_entry
, &group_leader
->sibling_list
);
1667 group_leader
->nr_siblings
++;
1669 perf_event__header_size(group_leader
);
1671 list_for_each_entry(pos
, &group_leader
->sibling_list
, group_entry
)
1672 perf_event__header_size(pos
);
1676 * Remove a event from the lists for its context.
1677 * Must be called with ctx->mutex and ctx->lock held.
1680 list_del_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
1682 WARN_ON_ONCE(event
->ctx
!= ctx
);
1683 lockdep_assert_held(&ctx
->lock
);
1686 * We can have double detach due to exit/hot-unplug + close.
1688 if (!(event
->attach_state
& PERF_ATTACH_CONTEXT
))
1691 event
->attach_state
&= ~PERF_ATTACH_CONTEXT
;
1693 list_update_cgroup_event(event
, ctx
, false);
1696 if (event
->attr
.inherit_stat
)
1699 list_del_rcu(&event
->event_entry
);
1701 if (event
->group_leader
== event
)
1702 list_del_init(&event
->group_entry
);
1704 update_group_times(event
);
1707 * If event was in error state, then keep it
1708 * that way, otherwise bogus counts will be
1709 * returned on read(). The only way to get out
1710 * of error state is by explicit re-enabling
1713 if (event
->state
> PERF_EVENT_STATE_OFF
)
1714 event
->state
= PERF_EVENT_STATE_OFF
;
1719 static void perf_group_detach(struct perf_event
*event
)
1721 struct perf_event
*sibling
, *tmp
;
1722 struct list_head
*list
= NULL
;
1724 lockdep_assert_held(&event
->ctx
->lock
);
1727 * We can have double detach due to exit/hot-unplug + close.
1729 if (!(event
->attach_state
& PERF_ATTACH_GROUP
))
1732 event
->attach_state
&= ~PERF_ATTACH_GROUP
;
1735 * If this is a sibling, remove it from its group.
1737 if (event
->group_leader
!= event
) {
1738 list_del_init(&event
->group_entry
);
1739 event
->group_leader
->nr_siblings
--;
1743 if (!list_empty(&event
->group_entry
))
1744 list
= &event
->group_entry
;
1747 * If this was a group event with sibling events then
1748 * upgrade the siblings to singleton events by adding them
1749 * to whatever list we are on.
1751 list_for_each_entry_safe(sibling
, tmp
, &event
->sibling_list
, group_entry
) {
1753 list_move_tail(&sibling
->group_entry
, list
);
1754 sibling
->group_leader
= sibling
;
1756 /* Inherit group flags from the previous leader */
1757 sibling
->group_caps
= event
->group_caps
;
1759 WARN_ON_ONCE(sibling
->ctx
!= event
->ctx
);
1763 perf_event__header_size(event
->group_leader
);
1765 list_for_each_entry(tmp
, &event
->group_leader
->sibling_list
, group_entry
)
1766 perf_event__header_size(tmp
);
1769 static bool is_orphaned_event(struct perf_event
*event
)
1771 return event
->state
== PERF_EVENT_STATE_DEAD
;
1774 static inline int __pmu_filter_match(struct perf_event
*event
)
1776 struct pmu
*pmu
= event
->pmu
;
1777 return pmu
->filter_match
? pmu
->filter_match(event
) : 1;
1781 * Check whether we should attempt to schedule an event group based on
1782 * PMU-specific filtering. An event group can consist of HW and SW events,
1783 * potentially with a SW leader, so we must check all the filters, to
1784 * determine whether a group is schedulable:
1786 static inline int pmu_filter_match(struct perf_event
*event
)
1788 struct perf_event
*child
;
1790 if (!__pmu_filter_match(event
))
1793 list_for_each_entry(child
, &event
->sibling_list
, group_entry
) {
1794 if (!__pmu_filter_match(child
))
1802 event_filter_match(struct perf_event
*event
)
1804 return (event
->cpu
== -1 || event
->cpu
== smp_processor_id()) &&
1805 perf_cgroup_match(event
) && pmu_filter_match(event
);
1809 event_sched_out(struct perf_event
*event
,
1810 struct perf_cpu_context
*cpuctx
,
1811 struct perf_event_context
*ctx
)
1813 u64 tstamp
= perf_event_time(event
);
1816 WARN_ON_ONCE(event
->ctx
!= ctx
);
1817 lockdep_assert_held(&ctx
->lock
);
1820 * An event which could not be activated because of
1821 * filter mismatch still needs to have its timings
1822 * maintained, otherwise bogus information is return
1823 * via read() for time_enabled, time_running:
1825 if (event
->state
== PERF_EVENT_STATE_INACTIVE
&&
1826 !event_filter_match(event
)) {
1827 delta
= tstamp
- event
->tstamp_stopped
;
1828 event
->tstamp_running
+= delta
;
1829 event
->tstamp_stopped
= tstamp
;
1832 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
1835 perf_pmu_disable(event
->pmu
);
1837 event
->tstamp_stopped
= tstamp
;
1838 event
->pmu
->del(event
, 0);
1840 event
->state
= PERF_EVENT_STATE_INACTIVE
;
1841 if (event
->pending_disable
) {
1842 event
->pending_disable
= 0;
1843 event
->state
= PERF_EVENT_STATE_OFF
;
1846 if (!is_software_event(event
))
1847 cpuctx
->active_oncpu
--;
1848 if (!--ctx
->nr_active
)
1849 perf_event_ctx_deactivate(ctx
);
1850 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
1852 if (event
->attr
.exclusive
|| !cpuctx
->active_oncpu
)
1853 cpuctx
->exclusive
= 0;
1855 perf_pmu_enable(event
->pmu
);
1859 group_sched_out(struct perf_event
*group_event
,
1860 struct perf_cpu_context
*cpuctx
,
1861 struct perf_event_context
*ctx
)
1863 struct perf_event
*event
;
1864 int state
= group_event
->state
;
1866 perf_pmu_disable(ctx
->pmu
);
1868 event_sched_out(group_event
, cpuctx
, ctx
);
1871 * Schedule out siblings (if any):
1873 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
)
1874 event_sched_out(event
, cpuctx
, ctx
);
1876 perf_pmu_enable(ctx
->pmu
);
1878 if (state
== PERF_EVENT_STATE_ACTIVE
&& group_event
->attr
.exclusive
)
1879 cpuctx
->exclusive
= 0;
1882 #define DETACH_GROUP 0x01UL
1885 * Cross CPU call to remove a performance event
1887 * We disable the event on the hardware level first. After that we
1888 * remove it from the context list.
1891 __perf_remove_from_context(struct perf_event
*event
,
1892 struct perf_cpu_context
*cpuctx
,
1893 struct perf_event_context
*ctx
,
1896 unsigned long flags
= (unsigned long)info
;
1898 event_sched_out(event
, cpuctx
, ctx
);
1899 if (flags
& DETACH_GROUP
)
1900 perf_group_detach(event
);
1901 list_del_event(event
, ctx
);
1903 if (!ctx
->nr_events
&& ctx
->is_active
) {
1906 WARN_ON_ONCE(cpuctx
->task_ctx
!= ctx
);
1907 cpuctx
->task_ctx
= NULL
;
1913 * Remove the event from a task's (or a CPU's) list of events.
1915 * If event->ctx is a cloned context, callers must make sure that
1916 * every task struct that event->ctx->task could possibly point to
1917 * remains valid. This is OK when called from perf_release since
1918 * that only calls us on the top-level context, which can't be a clone.
1919 * When called from perf_event_exit_task, it's OK because the
1920 * context has been detached from its task.
1922 static void perf_remove_from_context(struct perf_event
*event
, unsigned long flags
)
1924 struct perf_event_context
*ctx
= event
->ctx
;
1926 lockdep_assert_held(&ctx
->mutex
);
1928 event_function_call(event
, __perf_remove_from_context
, (void *)flags
);
1931 * The above event_function_call() can NO-OP when it hits
1932 * TASK_TOMBSTONE. In that case we must already have been detached
1933 * from the context (by perf_event_exit_event()) but the grouping
1934 * might still be in-tact.
1936 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_CONTEXT
);
1937 if ((flags
& DETACH_GROUP
) &&
1938 (event
->attach_state
& PERF_ATTACH_GROUP
)) {
1940 * Since in that case we cannot possibly be scheduled, simply
1943 raw_spin_lock_irq(&ctx
->lock
);
1944 perf_group_detach(event
);
1945 raw_spin_unlock_irq(&ctx
->lock
);
1950 * Cross CPU call to disable a performance event
1952 static void __perf_event_disable(struct perf_event
*event
,
1953 struct perf_cpu_context
*cpuctx
,
1954 struct perf_event_context
*ctx
,
1957 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
1960 update_context_time(ctx
);
1961 update_cgrp_time_from_event(event
);
1962 update_group_times(event
);
1963 if (event
== event
->group_leader
)
1964 group_sched_out(event
, cpuctx
, ctx
);
1966 event_sched_out(event
, cpuctx
, ctx
);
1967 event
->state
= PERF_EVENT_STATE_OFF
;
1973 * If event->ctx is a cloned context, callers must make sure that
1974 * every task struct that event->ctx->task could possibly point to
1975 * remains valid. This condition is satisifed when called through
1976 * perf_event_for_each_child or perf_event_for_each because they
1977 * hold the top-level event's child_mutex, so any descendant that
1978 * goes to exit will block in perf_event_exit_event().
1980 * When called from perf_pending_event it's OK because event->ctx
1981 * is the current context on this CPU and preemption is disabled,
1982 * hence we can't get into perf_event_task_sched_out for this context.
1984 static void _perf_event_disable(struct perf_event
*event
)
1986 struct perf_event_context
*ctx
= event
->ctx
;
1988 raw_spin_lock_irq(&ctx
->lock
);
1989 if (event
->state
<= PERF_EVENT_STATE_OFF
) {
1990 raw_spin_unlock_irq(&ctx
->lock
);
1993 raw_spin_unlock_irq(&ctx
->lock
);
1995 event_function_call(event
, __perf_event_disable
, NULL
);
1998 void perf_event_disable_local(struct perf_event
*event
)
2000 event_function_local(event
, __perf_event_disable
, NULL
);
2004 * Strictly speaking kernel users cannot create groups and therefore this
2005 * interface does not need the perf_event_ctx_lock() magic.
2007 void perf_event_disable(struct perf_event
*event
)
2009 struct perf_event_context
*ctx
;
2011 ctx
= perf_event_ctx_lock(event
);
2012 _perf_event_disable(event
);
2013 perf_event_ctx_unlock(event
, ctx
);
2015 EXPORT_SYMBOL_GPL(perf_event_disable
);
2017 void perf_event_disable_inatomic(struct perf_event
*event
)
2019 event
->pending_disable
= 1;
2020 irq_work_queue(&event
->pending
);
2023 static void perf_set_shadow_time(struct perf_event
*event
,
2024 struct perf_event_context
*ctx
,
2028 * use the correct time source for the time snapshot
2030 * We could get by without this by leveraging the
2031 * fact that to get to this function, the caller
2032 * has most likely already called update_context_time()
2033 * and update_cgrp_time_xx() and thus both timestamp
2034 * are identical (or very close). Given that tstamp is,
2035 * already adjusted for cgroup, we could say that:
2036 * tstamp - ctx->timestamp
2038 * tstamp - cgrp->timestamp.
2040 * Then, in perf_output_read(), the calculation would
2041 * work with no changes because:
2042 * - event is guaranteed scheduled in
2043 * - no scheduled out in between
2044 * - thus the timestamp would be the same
2046 * But this is a bit hairy.
2048 * So instead, we have an explicit cgroup call to remain
2049 * within the time time source all along. We believe it
2050 * is cleaner and simpler to understand.
2052 if (is_cgroup_event(event
))
2053 perf_cgroup_set_shadow_time(event
, tstamp
);
2055 event
->shadow_ctx_time
= tstamp
- ctx
->timestamp
;
2058 #define MAX_INTERRUPTS (~0ULL)
2060 static void perf_log_throttle(struct perf_event
*event
, int enable
);
2061 static void perf_log_itrace_start(struct perf_event
*event
);
2064 event_sched_in(struct perf_event
*event
,
2065 struct perf_cpu_context
*cpuctx
,
2066 struct perf_event_context
*ctx
)
2068 u64 tstamp
= perf_event_time(event
);
2071 lockdep_assert_held(&ctx
->lock
);
2073 if (event
->state
<= PERF_EVENT_STATE_OFF
)
2076 WRITE_ONCE(event
->oncpu
, smp_processor_id());
2078 * Order event::oncpu write to happen before the ACTIVE state
2082 WRITE_ONCE(event
->state
, PERF_EVENT_STATE_ACTIVE
);
2085 * Unthrottle events, since we scheduled we might have missed several
2086 * ticks already, also for a heavily scheduling task there is little
2087 * guarantee it'll get a tick in a timely manner.
2089 if (unlikely(event
->hw
.interrupts
== MAX_INTERRUPTS
)) {
2090 perf_log_throttle(event
, 1);
2091 event
->hw
.interrupts
= 0;
2095 * The new state must be visible before we turn it on in the hardware:
2099 perf_pmu_disable(event
->pmu
);
2101 perf_set_shadow_time(event
, ctx
, tstamp
);
2103 perf_log_itrace_start(event
);
2105 if (event
->pmu
->add(event
, PERF_EF_START
)) {
2106 event
->state
= PERF_EVENT_STATE_INACTIVE
;
2112 event
->tstamp_running
+= tstamp
- event
->tstamp_stopped
;
2114 if (!is_software_event(event
))
2115 cpuctx
->active_oncpu
++;
2116 if (!ctx
->nr_active
++)
2117 perf_event_ctx_activate(ctx
);
2118 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
2121 if (event
->attr
.exclusive
)
2122 cpuctx
->exclusive
= 1;
2125 perf_pmu_enable(event
->pmu
);
2131 group_sched_in(struct perf_event
*group_event
,
2132 struct perf_cpu_context
*cpuctx
,
2133 struct perf_event_context
*ctx
)
2135 struct perf_event
*event
, *partial_group
= NULL
;
2136 struct pmu
*pmu
= ctx
->pmu
;
2137 u64 now
= ctx
->time
;
2138 bool simulate
= false;
2140 if (group_event
->state
== PERF_EVENT_STATE_OFF
)
2143 pmu
->start_txn(pmu
, PERF_PMU_TXN_ADD
);
2145 if (event_sched_in(group_event
, cpuctx
, ctx
)) {
2146 pmu
->cancel_txn(pmu
);
2147 perf_mux_hrtimer_restart(cpuctx
);
2152 * Schedule in siblings as one group (if any):
2154 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
2155 if (event_sched_in(event
, cpuctx
, ctx
)) {
2156 partial_group
= event
;
2161 if (!pmu
->commit_txn(pmu
))
2166 * Groups can be scheduled in as one unit only, so undo any
2167 * partial group before returning:
2168 * The events up to the failed event are scheduled out normally,
2169 * tstamp_stopped will be updated.
2171 * The failed events and the remaining siblings need to have
2172 * their timings updated as if they had gone thru event_sched_in()
2173 * and event_sched_out(). This is required to get consistent timings
2174 * across the group. This also takes care of the case where the group
2175 * could never be scheduled by ensuring tstamp_stopped is set to mark
2176 * the time the event was actually stopped, such that time delta
2177 * calculation in update_event_times() is correct.
2179 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
2180 if (event
== partial_group
)
2184 event
->tstamp_running
+= now
- event
->tstamp_stopped
;
2185 event
->tstamp_stopped
= now
;
2187 event_sched_out(event
, cpuctx
, ctx
);
2190 event_sched_out(group_event
, cpuctx
, ctx
);
2192 pmu
->cancel_txn(pmu
);
2194 perf_mux_hrtimer_restart(cpuctx
);
2200 * Work out whether we can put this event group on the CPU now.
2202 static int group_can_go_on(struct perf_event
*event
,
2203 struct perf_cpu_context
*cpuctx
,
2207 * Groups consisting entirely of software events can always go on.
2209 if (event
->group_caps
& PERF_EV_CAP_SOFTWARE
)
2212 * If an exclusive group is already on, no other hardware
2215 if (cpuctx
->exclusive
)
2218 * If this group is exclusive and there are already
2219 * events on the CPU, it can't go on.
2221 if (event
->attr
.exclusive
&& cpuctx
->active_oncpu
)
2224 * Otherwise, try to add it if all previous groups were able
2231 * Complement to update_event_times(). This computes the tstamp_* values to
2232 * continue 'enabled' state from @now, and effectively discards the time
2233 * between the prior tstamp_stopped and now (as we were in the OFF state, or
2234 * just switched (context) time base).
2236 * This further assumes '@event->state == INACTIVE' (we just came from OFF) and
2237 * cannot have been scheduled in yet. And going into INACTIVE state means
2238 * '@event->tstamp_stopped = @now'.
2240 * Thus given the rules of update_event_times():
2242 * total_time_enabled = tstamp_stopped - tstamp_enabled
2243 * total_time_running = tstamp_stopped - tstamp_running
2245 * We can insert 'tstamp_stopped == now' and reverse them to compute new
2248 static void __perf_event_enable_time(struct perf_event
*event
, u64 now
)
2250 WARN_ON_ONCE(event
->state
!= PERF_EVENT_STATE_INACTIVE
);
2252 event
->tstamp_stopped
= now
;
2253 event
->tstamp_enabled
= now
- event
->total_time_enabled
;
2254 event
->tstamp_running
= now
- event
->total_time_running
;
2257 static void add_event_to_ctx(struct perf_event
*event
,
2258 struct perf_event_context
*ctx
)
2260 u64 tstamp
= perf_event_time(event
);
2262 list_add_event(event
, ctx
);
2263 perf_group_attach(event
);
2265 * We can be called with event->state == STATE_OFF when we create with
2266 * .disabled = 1. In that case the IOC_ENABLE will call this function.
2268 if (event
->state
== PERF_EVENT_STATE_INACTIVE
)
2269 __perf_event_enable_time(event
, tstamp
);
2272 static void ctx_sched_out(struct perf_event_context
*ctx
,
2273 struct perf_cpu_context
*cpuctx
,
2274 enum event_type_t event_type
);
2276 ctx_sched_in(struct perf_event_context
*ctx
,
2277 struct perf_cpu_context
*cpuctx
,
2278 enum event_type_t event_type
,
2279 struct task_struct
*task
);
2281 static void task_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
2282 struct perf_event_context
*ctx
,
2283 enum event_type_t event_type
)
2285 if (!cpuctx
->task_ctx
)
2288 if (WARN_ON_ONCE(ctx
!= cpuctx
->task_ctx
))
2291 ctx_sched_out(ctx
, cpuctx
, event_type
);
2294 static void perf_event_sched_in(struct perf_cpu_context
*cpuctx
,
2295 struct perf_event_context
*ctx
,
2296 struct task_struct
*task
)
2298 cpu_ctx_sched_in(cpuctx
, EVENT_PINNED
, task
);
2300 ctx_sched_in(ctx
, cpuctx
, EVENT_PINNED
, task
);
2301 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
, task
);
2303 ctx_sched_in(ctx
, cpuctx
, EVENT_FLEXIBLE
, task
);
2307 * We want to maintain the following priority of scheduling:
2308 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2309 * - task pinned (EVENT_PINNED)
2310 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2311 * - task flexible (EVENT_FLEXIBLE).
2313 * In order to avoid unscheduling and scheduling back in everything every
2314 * time an event is added, only do it for the groups of equal priority and
2317 * This can be called after a batch operation on task events, in which case
2318 * event_type is a bit mask of the types of events involved. For CPU events,
2319 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2321 static void ctx_resched(struct perf_cpu_context
*cpuctx
,
2322 struct perf_event_context
*task_ctx
,
2323 enum event_type_t event_type
)
2325 enum event_type_t ctx_event_type
= event_type
& EVENT_ALL
;
2326 bool cpu_event
= !!(event_type
& EVENT_CPU
);
2329 * If pinned groups are involved, flexible groups also need to be
2332 if (event_type
& EVENT_PINNED
)
2333 event_type
|= EVENT_FLEXIBLE
;
2335 perf_pmu_disable(cpuctx
->ctx
.pmu
);
2337 task_ctx_sched_out(cpuctx
, task_ctx
, event_type
);
2340 * Decide which cpu ctx groups to schedule out based on the types
2341 * of events that caused rescheduling:
2342 * - EVENT_CPU: schedule out corresponding groups;
2343 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2344 * - otherwise, do nothing more.
2347 cpu_ctx_sched_out(cpuctx
, ctx_event_type
);
2348 else if (ctx_event_type
& EVENT_PINNED
)
2349 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
2351 perf_event_sched_in(cpuctx
, task_ctx
, current
);
2352 perf_pmu_enable(cpuctx
->ctx
.pmu
);
2356 * Cross CPU call to install and enable a performance event
2358 * Very similar to remote_function() + event_function() but cannot assume that
2359 * things like ctx->is_active and cpuctx->task_ctx are set.
2361 static int __perf_install_in_context(void *info
)
2363 struct perf_event
*event
= info
;
2364 struct perf_event_context
*ctx
= event
->ctx
;
2365 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
2366 struct perf_event_context
*task_ctx
= cpuctx
->task_ctx
;
2367 bool reprogram
= true;
2370 raw_spin_lock(&cpuctx
->ctx
.lock
);
2372 raw_spin_lock(&ctx
->lock
);
2375 reprogram
= (ctx
->task
== current
);
2378 * If the task is running, it must be running on this CPU,
2379 * otherwise we cannot reprogram things.
2381 * If its not running, we don't care, ctx->lock will
2382 * serialize against it becoming runnable.
2384 if (task_curr(ctx
->task
) && !reprogram
) {
2389 WARN_ON_ONCE(reprogram
&& cpuctx
->task_ctx
&& cpuctx
->task_ctx
!= ctx
);
2390 } else if (task_ctx
) {
2391 raw_spin_lock(&task_ctx
->lock
);
2395 ctx_sched_out(ctx
, cpuctx
, EVENT_TIME
);
2396 add_event_to_ctx(event
, ctx
);
2397 ctx_resched(cpuctx
, task_ctx
, get_event_type(event
));
2399 add_event_to_ctx(event
, ctx
);
2403 perf_ctx_unlock(cpuctx
, task_ctx
);
2409 * Attach a performance event to a context.
2411 * Very similar to event_function_call, see comment there.
2414 perf_install_in_context(struct perf_event_context
*ctx
,
2415 struct perf_event
*event
,
2418 struct task_struct
*task
= READ_ONCE(ctx
->task
);
2420 lockdep_assert_held(&ctx
->mutex
);
2422 if (event
->cpu
!= -1)
2426 * Ensures that if we can observe event->ctx, both the event and ctx
2427 * will be 'complete'. See perf_iterate_sb_cpu().
2429 smp_store_release(&event
->ctx
, ctx
);
2432 cpu_function_call(cpu
, __perf_install_in_context
, event
);
2437 * Should not happen, we validate the ctx is still alive before calling.
2439 if (WARN_ON_ONCE(task
== TASK_TOMBSTONE
))
2443 * Installing events is tricky because we cannot rely on ctx->is_active
2444 * to be set in case this is the nr_events 0 -> 1 transition.
2446 * Instead we use task_curr(), which tells us if the task is running.
2447 * However, since we use task_curr() outside of rq::lock, we can race
2448 * against the actual state. This means the result can be wrong.
2450 * If we get a false positive, we retry, this is harmless.
2452 * If we get a false negative, things are complicated. If we are after
2453 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2454 * value must be correct. If we're before, it doesn't matter since
2455 * perf_event_context_sched_in() will program the counter.
2457 * However, this hinges on the remote context switch having observed
2458 * our task->perf_event_ctxp[] store, such that it will in fact take
2459 * ctx::lock in perf_event_context_sched_in().
2461 * We do this by task_function_call(), if the IPI fails to hit the task
2462 * we know any future context switch of task must see the
2463 * perf_event_ctpx[] store.
2467 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2468 * task_cpu() load, such that if the IPI then does not find the task
2469 * running, a future context switch of that task must observe the
2474 if (!task_function_call(task
, __perf_install_in_context
, event
))
2477 raw_spin_lock_irq(&ctx
->lock
);
2479 if (WARN_ON_ONCE(task
== TASK_TOMBSTONE
)) {
2481 * Cannot happen because we already checked above (which also
2482 * cannot happen), and we hold ctx->mutex, which serializes us
2483 * against perf_event_exit_task_context().
2485 raw_spin_unlock_irq(&ctx
->lock
);
2489 * If the task is not running, ctx->lock will avoid it becoming so,
2490 * thus we can safely install the event.
2492 if (task_curr(task
)) {
2493 raw_spin_unlock_irq(&ctx
->lock
);
2496 add_event_to_ctx(event
, ctx
);
2497 raw_spin_unlock_irq(&ctx
->lock
);
2501 * Put a event into inactive state and update time fields.
2502 * Enabling the leader of a group effectively enables all
2503 * the group members that aren't explicitly disabled, so we
2504 * have to update their ->tstamp_enabled also.
2505 * Note: this works for group members as well as group leaders
2506 * since the non-leader members' sibling_lists will be empty.
2508 static void __perf_event_mark_enabled(struct perf_event
*event
)
2510 struct perf_event
*sub
;
2511 u64 tstamp
= perf_event_time(event
);
2513 event
->state
= PERF_EVENT_STATE_INACTIVE
;
2514 __perf_event_enable_time(event
, tstamp
);
2515 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
2516 /* XXX should not be > INACTIVE if event isn't */
2517 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
)
2518 __perf_event_enable_time(sub
, tstamp
);
2523 * Cross CPU call to enable a performance event
2525 static void __perf_event_enable(struct perf_event
*event
,
2526 struct perf_cpu_context
*cpuctx
,
2527 struct perf_event_context
*ctx
,
2530 struct perf_event
*leader
= event
->group_leader
;
2531 struct perf_event_context
*task_ctx
;
2533 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
||
2534 event
->state
<= PERF_EVENT_STATE_ERROR
)
2538 ctx_sched_out(ctx
, cpuctx
, EVENT_TIME
);
2540 __perf_event_mark_enabled(event
);
2542 if (!ctx
->is_active
)
2545 if (!event_filter_match(event
)) {
2546 if (is_cgroup_event(event
))
2547 perf_cgroup_defer_enabled(event
);
2548 ctx_sched_in(ctx
, cpuctx
, EVENT_TIME
, current
);
2553 * If the event is in a group and isn't the group leader,
2554 * then don't put it on unless the group is on.
2556 if (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
) {
2557 ctx_sched_in(ctx
, cpuctx
, EVENT_TIME
, current
);
2561 task_ctx
= cpuctx
->task_ctx
;
2563 WARN_ON_ONCE(task_ctx
!= ctx
);
2565 ctx_resched(cpuctx
, task_ctx
, get_event_type(event
));
2571 * If event->ctx is a cloned context, callers must make sure that
2572 * every task struct that event->ctx->task could possibly point to
2573 * remains valid. This condition is satisfied when called through
2574 * perf_event_for_each_child or perf_event_for_each as described
2575 * for perf_event_disable.
2577 static void _perf_event_enable(struct perf_event
*event
)
2579 struct perf_event_context
*ctx
= event
->ctx
;
2581 raw_spin_lock_irq(&ctx
->lock
);
2582 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
||
2583 event
->state
< PERF_EVENT_STATE_ERROR
) {
2584 raw_spin_unlock_irq(&ctx
->lock
);
2589 * If the event is in error state, clear that first.
2591 * That way, if we see the event in error state below, we know that it
2592 * has gone back into error state, as distinct from the task having
2593 * been scheduled away before the cross-call arrived.
2595 if (event
->state
== PERF_EVENT_STATE_ERROR
)
2596 event
->state
= PERF_EVENT_STATE_OFF
;
2597 raw_spin_unlock_irq(&ctx
->lock
);
2599 event_function_call(event
, __perf_event_enable
, NULL
);
2603 * See perf_event_disable();
2605 void perf_event_enable(struct perf_event
*event
)
2607 struct perf_event_context
*ctx
;
2609 ctx
= perf_event_ctx_lock(event
);
2610 _perf_event_enable(event
);
2611 perf_event_ctx_unlock(event
, ctx
);
2613 EXPORT_SYMBOL_GPL(perf_event_enable
);
2615 struct stop_event_data
{
2616 struct perf_event
*event
;
2617 unsigned int restart
;
2620 static int __perf_event_stop(void *info
)
2622 struct stop_event_data
*sd
= info
;
2623 struct perf_event
*event
= sd
->event
;
2625 /* if it's already INACTIVE, do nothing */
2626 if (READ_ONCE(event
->state
) != PERF_EVENT_STATE_ACTIVE
)
2629 /* matches smp_wmb() in event_sched_in() */
2633 * There is a window with interrupts enabled before we get here,
2634 * so we need to check again lest we try to stop another CPU's event.
2636 if (READ_ONCE(event
->oncpu
) != smp_processor_id())
2639 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
2642 * May race with the actual stop (through perf_pmu_output_stop()),
2643 * but it is only used for events with AUX ring buffer, and such
2644 * events will refuse to restart because of rb::aux_mmap_count==0,
2645 * see comments in perf_aux_output_begin().
2647 * Since this is happening on a event-local CPU, no trace is lost
2651 event
->pmu
->start(event
, 0);
2656 static int perf_event_stop(struct perf_event
*event
, int restart
)
2658 struct stop_event_data sd
= {
2665 if (READ_ONCE(event
->state
) != PERF_EVENT_STATE_ACTIVE
)
2668 /* matches smp_wmb() in event_sched_in() */
2672 * We only want to restart ACTIVE events, so if the event goes
2673 * inactive here (event->oncpu==-1), there's nothing more to do;
2674 * fall through with ret==-ENXIO.
2676 ret
= cpu_function_call(READ_ONCE(event
->oncpu
),
2677 __perf_event_stop
, &sd
);
2678 } while (ret
== -EAGAIN
);
2684 * In order to contain the amount of racy and tricky in the address filter
2685 * configuration management, it is a two part process:
2687 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2688 * we update the addresses of corresponding vmas in
2689 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2690 * (p2) when an event is scheduled in (pmu::add), it calls
2691 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2692 * if the generation has changed since the previous call.
2694 * If (p1) happens while the event is active, we restart it to force (p2).
2696 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2697 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2699 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2700 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2702 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2705 void perf_event_addr_filters_sync(struct perf_event
*event
)
2707 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
2709 if (!has_addr_filter(event
))
2712 raw_spin_lock(&ifh
->lock
);
2713 if (event
->addr_filters_gen
!= event
->hw
.addr_filters_gen
) {
2714 event
->pmu
->addr_filters_sync(event
);
2715 event
->hw
.addr_filters_gen
= event
->addr_filters_gen
;
2717 raw_spin_unlock(&ifh
->lock
);
2719 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync
);
2721 static int _perf_event_refresh(struct perf_event
*event
, int refresh
)
2724 * not supported on inherited events
2726 if (event
->attr
.inherit
|| !is_sampling_event(event
))
2729 atomic_add(refresh
, &event
->event_limit
);
2730 _perf_event_enable(event
);
2736 * See perf_event_disable()
2738 int perf_event_refresh(struct perf_event
*event
, int refresh
)
2740 struct perf_event_context
*ctx
;
2743 ctx
= perf_event_ctx_lock(event
);
2744 ret
= _perf_event_refresh(event
, refresh
);
2745 perf_event_ctx_unlock(event
, ctx
);
2749 EXPORT_SYMBOL_GPL(perf_event_refresh
);
2751 static void ctx_sched_out(struct perf_event_context
*ctx
,
2752 struct perf_cpu_context
*cpuctx
,
2753 enum event_type_t event_type
)
2755 int is_active
= ctx
->is_active
;
2756 struct perf_event
*event
;
2758 lockdep_assert_held(&ctx
->lock
);
2760 if (likely(!ctx
->nr_events
)) {
2762 * See __perf_remove_from_context().
2764 WARN_ON_ONCE(ctx
->is_active
);
2766 WARN_ON_ONCE(cpuctx
->task_ctx
);
2770 ctx
->is_active
&= ~event_type
;
2771 if (!(ctx
->is_active
& EVENT_ALL
))
2775 WARN_ON_ONCE(cpuctx
->task_ctx
!= ctx
);
2776 if (!ctx
->is_active
)
2777 cpuctx
->task_ctx
= NULL
;
2781 * Always update time if it was set; not only when it changes.
2782 * Otherwise we can 'forget' to update time for any but the last
2783 * context we sched out. For example:
2785 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2786 * ctx_sched_out(.event_type = EVENT_PINNED)
2788 * would only update time for the pinned events.
2790 if (is_active
& EVENT_TIME
) {
2791 /* update (and stop) ctx time */
2792 update_context_time(ctx
);
2793 update_cgrp_time_from_cpuctx(cpuctx
);
2796 is_active
^= ctx
->is_active
; /* changed bits */
2798 if (!ctx
->nr_active
|| !(is_active
& EVENT_ALL
))
2801 perf_pmu_disable(ctx
->pmu
);
2802 if (is_active
& EVENT_PINNED
) {
2803 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
)
2804 group_sched_out(event
, cpuctx
, ctx
);
2807 if (is_active
& EVENT_FLEXIBLE
) {
2808 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
)
2809 group_sched_out(event
, cpuctx
, ctx
);
2811 perf_pmu_enable(ctx
->pmu
);
2815 * Test whether two contexts are equivalent, i.e. whether they have both been
2816 * cloned from the same version of the same context.
2818 * Equivalence is measured using a generation number in the context that is
2819 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2820 * and list_del_event().
2822 static int context_equiv(struct perf_event_context
*ctx1
,
2823 struct perf_event_context
*ctx2
)
2825 lockdep_assert_held(&ctx1
->lock
);
2826 lockdep_assert_held(&ctx2
->lock
);
2828 /* Pinning disables the swap optimization */
2829 if (ctx1
->pin_count
|| ctx2
->pin_count
)
2832 /* If ctx1 is the parent of ctx2 */
2833 if (ctx1
== ctx2
->parent_ctx
&& ctx1
->generation
== ctx2
->parent_gen
)
2836 /* If ctx2 is the parent of ctx1 */
2837 if (ctx1
->parent_ctx
== ctx2
&& ctx1
->parent_gen
== ctx2
->generation
)
2841 * If ctx1 and ctx2 have the same parent; we flatten the parent
2842 * hierarchy, see perf_event_init_context().
2844 if (ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
&&
2845 ctx1
->parent_gen
== ctx2
->parent_gen
)
2852 static void __perf_event_sync_stat(struct perf_event
*event
,
2853 struct perf_event
*next_event
)
2857 if (!event
->attr
.inherit_stat
)
2861 * Update the event value, we cannot use perf_event_read()
2862 * because we're in the middle of a context switch and have IRQs
2863 * disabled, which upsets smp_call_function_single(), however
2864 * we know the event must be on the current CPU, therefore we
2865 * don't need to use it.
2867 switch (event
->state
) {
2868 case PERF_EVENT_STATE_ACTIVE
:
2869 event
->pmu
->read(event
);
2872 case PERF_EVENT_STATE_INACTIVE
:
2873 update_event_times(event
);
2881 * In order to keep per-task stats reliable we need to flip the event
2882 * values when we flip the contexts.
2884 value
= local64_read(&next_event
->count
);
2885 value
= local64_xchg(&event
->count
, value
);
2886 local64_set(&next_event
->count
, value
);
2888 swap(event
->total_time_enabled
, next_event
->total_time_enabled
);
2889 swap(event
->total_time_running
, next_event
->total_time_running
);
2892 * Since we swizzled the values, update the user visible data too.
2894 perf_event_update_userpage(event
);
2895 perf_event_update_userpage(next_event
);
2898 static void perf_event_sync_stat(struct perf_event_context
*ctx
,
2899 struct perf_event_context
*next_ctx
)
2901 struct perf_event
*event
, *next_event
;
2906 update_context_time(ctx
);
2908 event
= list_first_entry(&ctx
->event_list
,
2909 struct perf_event
, event_entry
);
2911 next_event
= list_first_entry(&next_ctx
->event_list
,
2912 struct perf_event
, event_entry
);
2914 while (&event
->event_entry
!= &ctx
->event_list
&&
2915 &next_event
->event_entry
!= &next_ctx
->event_list
) {
2917 __perf_event_sync_stat(event
, next_event
);
2919 event
= list_next_entry(event
, event_entry
);
2920 next_event
= list_next_entry(next_event
, event_entry
);
2924 static void perf_event_context_sched_out(struct task_struct
*task
, int ctxn
,
2925 struct task_struct
*next
)
2927 struct perf_event_context
*ctx
= task
->perf_event_ctxp
[ctxn
];
2928 struct perf_event_context
*next_ctx
;
2929 struct perf_event_context
*parent
, *next_parent
;
2930 struct perf_cpu_context
*cpuctx
;
2936 cpuctx
= __get_cpu_context(ctx
);
2937 if (!cpuctx
->task_ctx
)
2941 next_ctx
= next
->perf_event_ctxp
[ctxn
];
2945 parent
= rcu_dereference(ctx
->parent_ctx
);
2946 next_parent
= rcu_dereference(next_ctx
->parent_ctx
);
2948 /* If neither context have a parent context; they cannot be clones. */
2949 if (!parent
&& !next_parent
)
2952 if (next_parent
== ctx
|| next_ctx
== parent
|| next_parent
== parent
) {
2954 * Looks like the two contexts are clones, so we might be
2955 * able to optimize the context switch. We lock both
2956 * contexts and check that they are clones under the
2957 * lock (including re-checking that neither has been
2958 * uncloned in the meantime). It doesn't matter which
2959 * order we take the locks because no other cpu could
2960 * be trying to lock both of these tasks.
2962 raw_spin_lock(&ctx
->lock
);
2963 raw_spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
2964 if (context_equiv(ctx
, next_ctx
)) {
2965 WRITE_ONCE(ctx
->task
, next
);
2966 WRITE_ONCE(next_ctx
->task
, task
);
2968 swap(ctx
->task_ctx_data
, next_ctx
->task_ctx_data
);
2971 * RCU_INIT_POINTER here is safe because we've not
2972 * modified the ctx and the above modification of
2973 * ctx->task and ctx->task_ctx_data are immaterial
2974 * since those values are always verified under
2975 * ctx->lock which we're now holding.
2977 RCU_INIT_POINTER(task
->perf_event_ctxp
[ctxn
], next_ctx
);
2978 RCU_INIT_POINTER(next
->perf_event_ctxp
[ctxn
], ctx
);
2982 perf_event_sync_stat(ctx
, next_ctx
);
2984 raw_spin_unlock(&next_ctx
->lock
);
2985 raw_spin_unlock(&ctx
->lock
);
2991 raw_spin_lock(&ctx
->lock
);
2992 task_ctx_sched_out(cpuctx
, ctx
, EVENT_ALL
);
2993 raw_spin_unlock(&ctx
->lock
);
2997 static DEFINE_PER_CPU(struct list_head
, sched_cb_list
);
2999 void perf_sched_cb_dec(struct pmu
*pmu
)
3001 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
3003 this_cpu_dec(perf_sched_cb_usages
);
3005 if (!--cpuctx
->sched_cb_usage
)
3006 list_del(&cpuctx
->sched_cb_entry
);
3010 void perf_sched_cb_inc(struct pmu
*pmu
)
3012 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
3014 if (!cpuctx
->sched_cb_usage
++)
3015 list_add(&cpuctx
->sched_cb_entry
, this_cpu_ptr(&sched_cb_list
));
3017 this_cpu_inc(perf_sched_cb_usages
);
3021 * This function provides the context switch callback to the lower code
3022 * layer. It is invoked ONLY when the context switch callback is enabled.
3024 * This callback is relevant even to per-cpu events; for example multi event
3025 * PEBS requires this to provide PID/TID information. This requires we flush
3026 * all queued PEBS records before we context switch to a new task.
3028 static void perf_pmu_sched_task(struct task_struct
*prev
,
3029 struct task_struct
*next
,
3032 struct perf_cpu_context
*cpuctx
;
3038 list_for_each_entry(cpuctx
, this_cpu_ptr(&sched_cb_list
), sched_cb_entry
) {
3039 pmu
= cpuctx
->ctx
.pmu
; /* software PMUs will not have sched_task */
3041 if (WARN_ON_ONCE(!pmu
->sched_task
))
3044 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
3045 perf_pmu_disable(pmu
);
3047 pmu
->sched_task(cpuctx
->task_ctx
, sched_in
);
3049 perf_pmu_enable(pmu
);
3050 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
3054 static void perf_event_switch(struct task_struct
*task
,
3055 struct task_struct
*next_prev
, bool sched_in
);
3057 #define for_each_task_context_nr(ctxn) \
3058 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3061 * Called from scheduler to remove the events of the current task,
3062 * with interrupts disabled.
3064 * We stop each event and update the event value in event->count.
3066 * This does not protect us against NMI, but disable()
3067 * sets the disabled bit in the control field of event _before_
3068 * accessing the event control register. If a NMI hits, then it will
3069 * not restart the event.
3071 void __perf_event_task_sched_out(struct task_struct
*task
,
3072 struct task_struct
*next
)
3076 if (__this_cpu_read(perf_sched_cb_usages
))
3077 perf_pmu_sched_task(task
, next
, false);
3079 if (atomic_read(&nr_switch_events
))
3080 perf_event_switch(task
, next
, false);
3082 for_each_task_context_nr(ctxn
)
3083 perf_event_context_sched_out(task
, ctxn
, next
);
3086 * if cgroup events exist on this CPU, then we need
3087 * to check if we have to switch out PMU state.
3088 * cgroup event are system-wide mode only
3090 if (atomic_read(this_cpu_ptr(&perf_cgroup_events
)))
3091 perf_cgroup_sched_out(task
, next
);
3095 * Called with IRQs disabled
3097 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
3098 enum event_type_t event_type
)
3100 ctx_sched_out(&cpuctx
->ctx
, cpuctx
, event_type
);
3104 ctx_pinned_sched_in(struct perf_event_context
*ctx
,
3105 struct perf_cpu_context
*cpuctx
)
3107 struct perf_event
*event
;
3109 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
3110 if (event
->state
<= PERF_EVENT_STATE_OFF
)
3112 if (!event_filter_match(event
))
3115 /* may need to reset tstamp_enabled */
3116 if (is_cgroup_event(event
))
3117 perf_cgroup_mark_enabled(event
, ctx
);
3119 if (group_can_go_on(event
, cpuctx
, 1))
3120 group_sched_in(event
, cpuctx
, ctx
);
3123 * If this pinned group hasn't been scheduled,
3124 * put it in error state.
3126 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
3127 update_group_times(event
);
3128 event
->state
= PERF_EVENT_STATE_ERROR
;
3134 ctx_flexible_sched_in(struct perf_event_context
*ctx
,
3135 struct perf_cpu_context
*cpuctx
)
3137 struct perf_event
*event
;
3140 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
3141 /* Ignore events in OFF or ERROR state */
3142 if (event
->state
<= PERF_EVENT_STATE_OFF
)
3145 * Listen to the 'cpu' scheduling filter constraint
3148 if (!event_filter_match(event
))
3151 /* may need to reset tstamp_enabled */
3152 if (is_cgroup_event(event
))
3153 perf_cgroup_mark_enabled(event
, ctx
);
3155 if (group_can_go_on(event
, cpuctx
, can_add_hw
)) {
3156 if (group_sched_in(event
, cpuctx
, ctx
))
3163 ctx_sched_in(struct perf_event_context
*ctx
,
3164 struct perf_cpu_context
*cpuctx
,
3165 enum event_type_t event_type
,
3166 struct task_struct
*task
)
3168 int is_active
= ctx
->is_active
;
3171 lockdep_assert_held(&ctx
->lock
);
3173 if (likely(!ctx
->nr_events
))
3176 ctx
->is_active
|= (event_type
| EVENT_TIME
);
3179 cpuctx
->task_ctx
= ctx
;
3181 WARN_ON_ONCE(cpuctx
->task_ctx
!= ctx
);
3184 is_active
^= ctx
->is_active
; /* changed bits */
3186 if (is_active
& EVENT_TIME
) {
3187 /* start ctx time */
3189 ctx
->timestamp
= now
;
3190 perf_cgroup_set_timestamp(task
, ctx
);
3194 * First go through the list and put on any pinned groups
3195 * in order to give them the best chance of going on.
3197 if (is_active
& EVENT_PINNED
)
3198 ctx_pinned_sched_in(ctx
, cpuctx
);
3200 /* Then walk through the lower prio flexible groups */
3201 if (is_active
& EVENT_FLEXIBLE
)
3202 ctx_flexible_sched_in(ctx
, cpuctx
);
3205 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
3206 enum event_type_t event_type
,
3207 struct task_struct
*task
)
3209 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
3211 ctx_sched_in(ctx
, cpuctx
, event_type
, task
);
3214 static void perf_event_context_sched_in(struct perf_event_context
*ctx
,
3215 struct task_struct
*task
)
3217 struct perf_cpu_context
*cpuctx
;
3219 cpuctx
= __get_cpu_context(ctx
);
3220 if (cpuctx
->task_ctx
== ctx
)
3223 perf_ctx_lock(cpuctx
, ctx
);
3225 * We must check ctx->nr_events while holding ctx->lock, such
3226 * that we serialize against perf_install_in_context().
3228 if (!ctx
->nr_events
)
3231 perf_pmu_disable(ctx
->pmu
);
3233 * We want to keep the following priority order:
3234 * cpu pinned (that don't need to move), task pinned,
3235 * cpu flexible, task flexible.
3237 * However, if task's ctx is not carrying any pinned
3238 * events, no need to flip the cpuctx's events around.
3240 if (!list_empty(&ctx
->pinned_groups
))
3241 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
3242 perf_event_sched_in(cpuctx
, ctx
, task
);
3243 perf_pmu_enable(ctx
->pmu
);
3246 perf_ctx_unlock(cpuctx
, ctx
);
3250 * Called from scheduler to add the events of the current task
3251 * with interrupts disabled.
3253 * We restore the event value and then enable it.
3255 * This does not protect us against NMI, but enable()
3256 * sets the enabled bit in the control field of event _before_
3257 * accessing the event control register. If a NMI hits, then it will
3258 * keep the event running.
3260 void __perf_event_task_sched_in(struct task_struct
*prev
,
3261 struct task_struct
*task
)
3263 struct perf_event_context
*ctx
;
3267 * If cgroup events exist on this CPU, then we need to check if we have
3268 * to switch in PMU state; cgroup event are system-wide mode only.
3270 * Since cgroup events are CPU events, we must schedule these in before
3271 * we schedule in the task events.
3273 if (atomic_read(this_cpu_ptr(&perf_cgroup_events
)))
3274 perf_cgroup_sched_in(prev
, task
);
3276 for_each_task_context_nr(ctxn
) {
3277 ctx
= task
->perf_event_ctxp
[ctxn
];
3281 perf_event_context_sched_in(ctx
, task
);
3284 if (atomic_read(&nr_switch_events
))
3285 perf_event_switch(task
, prev
, true);
3287 if (__this_cpu_read(perf_sched_cb_usages
))
3288 perf_pmu_sched_task(prev
, task
, true);
3291 static u64
perf_calculate_period(struct perf_event
*event
, u64 nsec
, u64 count
)
3293 u64 frequency
= event
->attr
.sample_freq
;
3294 u64 sec
= NSEC_PER_SEC
;
3295 u64 divisor
, dividend
;
3297 int count_fls
, nsec_fls
, frequency_fls
, sec_fls
;
3299 count_fls
= fls64(count
);
3300 nsec_fls
= fls64(nsec
);
3301 frequency_fls
= fls64(frequency
);
3305 * We got @count in @nsec, with a target of sample_freq HZ
3306 * the target period becomes:
3309 * period = -------------------
3310 * @nsec * sample_freq
3315 * Reduce accuracy by one bit such that @a and @b converge
3316 * to a similar magnitude.
3318 #define REDUCE_FLS(a, b) \
3320 if (a##_fls > b##_fls) { \
3330 * Reduce accuracy until either term fits in a u64, then proceed with
3331 * the other, so that finally we can do a u64/u64 division.
3333 while (count_fls
+ sec_fls
> 64 && nsec_fls
+ frequency_fls
> 64) {
3334 REDUCE_FLS(nsec
, frequency
);
3335 REDUCE_FLS(sec
, count
);
3338 if (count_fls
+ sec_fls
> 64) {
3339 divisor
= nsec
* frequency
;
3341 while (count_fls
+ sec_fls
> 64) {
3342 REDUCE_FLS(count
, sec
);
3346 dividend
= count
* sec
;
3348 dividend
= count
* sec
;
3350 while (nsec_fls
+ frequency_fls
> 64) {
3351 REDUCE_FLS(nsec
, frequency
);
3355 divisor
= nsec
* frequency
;
3361 return div64_u64(dividend
, divisor
);
3364 static DEFINE_PER_CPU(int, perf_throttled_count
);
3365 static DEFINE_PER_CPU(u64
, perf_throttled_seq
);
3367 static void perf_adjust_period(struct perf_event
*event
, u64 nsec
, u64 count
, bool disable
)
3369 struct hw_perf_event
*hwc
= &event
->hw
;
3370 s64 period
, sample_period
;
3373 period
= perf_calculate_period(event
, nsec
, count
);
3375 delta
= (s64
)(period
- hwc
->sample_period
);
3376 delta
= (delta
+ 7) / 8; /* low pass filter */
3378 sample_period
= hwc
->sample_period
+ delta
;
3383 hwc
->sample_period
= sample_period
;
3385 if (local64_read(&hwc
->period_left
) > 8*sample_period
) {
3387 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
3389 local64_set(&hwc
->period_left
, 0);
3392 event
->pmu
->start(event
, PERF_EF_RELOAD
);
3397 * combine freq adjustment with unthrottling to avoid two passes over the
3398 * events. At the same time, make sure, having freq events does not change
3399 * the rate of unthrottling as that would introduce bias.
3401 static void perf_adjust_freq_unthr_context(struct perf_event_context
*ctx
,
3404 struct perf_event
*event
;
3405 struct hw_perf_event
*hwc
;
3406 u64 now
, period
= TICK_NSEC
;
3410 * only need to iterate over all events iff:
3411 * - context have events in frequency mode (needs freq adjust)
3412 * - there are events to unthrottle on this cpu
3414 if (!(ctx
->nr_freq
|| needs_unthr
))
3417 raw_spin_lock(&ctx
->lock
);
3418 perf_pmu_disable(ctx
->pmu
);
3420 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3421 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
3424 if (!event_filter_match(event
))
3427 perf_pmu_disable(event
->pmu
);
3431 if (hwc
->interrupts
== MAX_INTERRUPTS
) {
3432 hwc
->interrupts
= 0;
3433 perf_log_throttle(event
, 1);
3434 event
->pmu
->start(event
, 0);
3437 if (!event
->attr
.freq
|| !event
->attr
.sample_freq
)
3441 * stop the event and update event->count
3443 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
3445 now
= local64_read(&event
->count
);
3446 delta
= now
- hwc
->freq_count_stamp
;
3447 hwc
->freq_count_stamp
= now
;
3451 * reload only if value has changed
3452 * we have stopped the event so tell that
3453 * to perf_adjust_period() to avoid stopping it
3457 perf_adjust_period(event
, period
, delta
, false);
3459 event
->pmu
->start(event
, delta
> 0 ? PERF_EF_RELOAD
: 0);
3461 perf_pmu_enable(event
->pmu
);
3464 perf_pmu_enable(ctx
->pmu
);
3465 raw_spin_unlock(&ctx
->lock
);
3469 * Round-robin a context's events:
3471 static void rotate_ctx(struct perf_event_context
*ctx
)
3474 * Rotate the first entry last of non-pinned groups. Rotation might be
3475 * disabled by the inheritance code.
3477 if (!ctx
->rotate_disable
)
3478 list_rotate_left(&ctx
->flexible_groups
);
3481 static int perf_rotate_context(struct perf_cpu_context
*cpuctx
)
3483 struct perf_event_context
*ctx
= NULL
;
3486 if (cpuctx
->ctx
.nr_events
) {
3487 if (cpuctx
->ctx
.nr_events
!= cpuctx
->ctx
.nr_active
)
3491 ctx
= cpuctx
->task_ctx
;
3492 if (ctx
&& ctx
->nr_events
) {
3493 if (ctx
->nr_events
!= ctx
->nr_active
)
3500 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
3501 perf_pmu_disable(cpuctx
->ctx
.pmu
);
3503 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
3505 ctx_sched_out(ctx
, cpuctx
, EVENT_FLEXIBLE
);
3507 rotate_ctx(&cpuctx
->ctx
);
3511 perf_event_sched_in(cpuctx
, ctx
, current
);
3513 perf_pmu_enable(cpuctx
->ctx
.pmu
);
3514 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
3520 void perf_event_task_tick(void)
3522 struct list_head
*head
= this_cpu_ptr(&active_ctx_list
);
3523 struct perf_event_context
*ctx
, *tmp
;
3526 WARN_ON(!irqs_disabled());
3528 __this_cpu_inc(perf_throttled_seq
);
3529 throttled
= __this_cpu_xchg(perf_throttled_count
, 0);
3530 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS
);
3532 list_for_each_entry_safe(ctx
, tmp
, head
, active_ctx_list
)
3533 perf_adjust_freq_unthr_context(ctx
, throttled
);
3536 static int event_enable_on_exec(struct perf_event
*event
,
3537 struct perf_event_context
*ctx
)
3539 if (!event
->attr
.enable_on_exec
)
3542 event
->attr
.enable_on_exec
= 0;
3543 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
3546 __perf_event_mark_enabled(event
);
3552 * Enable all of a task's events that have been marked enable-on-exec.
3553 * This expects task == current.
3555 static void perf_event_enable_on_exec(int ctxn
)
3557 struct perf_event_context
*ctx
, *clone_ctx
= NULL
;
3558 enum event_type_t event_type
= 0;
3559 struct perf_cpu_context
*cpuctx
;
3560 struct perf_event
*event
;
3561 unsigned long flags
;
3564 local_irq_save(flags
);
3565 ctx
= current
->perf_event_ctxp
[ctxn
];
3566 if (!ctx
|| !ctx
->nr_events
)
3569 cpuctx
= __get_cpu_context(ctx
);
3570 perf_ctx_lock(cpuctx
, ctx
);
3571 ctx_sched_out(ctx
, cpuctx
, EVENT_TIME
);
3572 list_for_each_entry(event
, &ctx
->event_list
, event_entry
) {
3573 enabled
|= event_enable_on_exec(event
, ctx
);
3574 event_type
|= get_event_type(event
);
3578 * Unclone and reschedule this context if we enabled any event.
3581 clone_ctx
= unclone_ctx(ctx
);
3582 ctx_resched(cpuctx
, ctx
, event_type
);
3584 ctx_sched_in(ctx
, cpuctx
, EVENT_TIME
, current
);
3586 perf_ctx_unlock(cpuctx
, ctx
);
3589 local_irq_restore(flags
);
3595 struct perf_read_data
{
3596 struct perf_event
*event
;
3601 static int __perf_event_read_cpu(struct perf_event
*event
, int event_cpu
)
3603 u16 local_pkg
, event_pkg
;
3605 if (event
->group_caps
& PERF_EV_CAP_READ_ACTIVE_PKG
) {
3606 int local_cpu
= smp_processor_id();
3608 event_pkg
= topology_physical_package_id(event_cpu
);
3609 local_pkg
= topology_physical_package_id(local_cpu
);
3611 if (event_pkg
== local_pkg
)
3619 * Cross CPU call to read the hardware event
3621 static void __perf_event_read(void *info
)
3623 struct perf_read_data
*data
= info
;
3624 struct perf_event
*sub
, *event
= data
->event
;
3625 struct perf_event_context
*ctx
= event
->ctx
;
3626 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
3627 struct pmu
*pmu
= event
->pmu
;
3630 * If this is a task context, we need to check whether it is
3631 * the current task context of this cpu. If not it has been
3632 * scheduled out before the smp call arrived. In that case
3633 * event->count would have been updated to a recent sample
3634 * when the event was scheduled out.
3636 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
3639 raw_spin_lock(&ctx
->lock
);
3640 if (ctx
->is_active
) {
3641 update_context_time(ctx
);
3642 update_cgrp_time_from_event(event
);
3645 update_event_times(event
);
3646 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
3655 pmu
->start_txn(pmu
, PERF_PMU_TXN_READ
);
3659 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
3660 update_event_times(sub
);
3661 if (sub
->state
== PERF_EVENT_STATE_ACTIVE
) {
3663 * Use sibling's PMU rather than @event's since
3664 * sibling could be on different (eg: software) PMU.
3666 sub
->pmu
->read(sub
);
3670 data
->ret
= pmu
->commit_txn(pmu
);
3673 raw_spin_unlock(&ctx
->lock
);
3676 static inline u64
perf_event_count(struct perf_event
*event
)
3678 return local64_read(&event
->count
) + atomic64_read(&event
->child_count
);
3682 * NMI-safe method to read a local event, that is an event that
3684 * - either for the current task, or for this CPU
3685 * - does not have inherit set, for inherited task events
3686 * will not be local and we cannot read them atomically
3687 * - must not have a pmu::count method
3689 int perf_event_read_local(struct perf_event
*event
, u64
*value
)
3691 unsigned long flags
;
3695 * Disabling interrupts avoids all counter scheduling (context
3696 * switches, timer based rotation and IPIs).
3698 local_irq_save(flags
);
3701 * It must not be an event with inherit set, we cannot read
3702 * all child counters from atomic context.
3704 if (event
->attr
.inherit
) {
3709 /* If this is a per-task event, it must be for current */
3710 if ((event
->attach_state
& PERF_ATTACH_TASK
) &&
3711 event
->hw
.target
!= current
) {
3716 /* If this is a per-CPU event, it must be for this CPU */
3717 if (!(event
->attach_state
& PERF_ATTACH_TASK
) &&
3718 event
->cpu
!= smp_processor_id()) {
3724 * If the event is currently on this CPU, its either a per-task event,
3725 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3728 if (event
->oncpu
== smp_processor_id())
3729 event
->pmu
->read(event
);
3731 *value
= local64_read(&event
->count
);
3733 local_irq_restore(flags
);
3738 static int perf_event_read(struct perf_event
*event
, bool group
)
3740 int event_cpu
, ret
= 0;
3743 * If event is enabled and currently active on a CPU, update the
3744 * value in the event structure:
3746 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
3747 struct perf_read_data data
= {
3753 event_cpu
= READ_ONCE(event
->oncpu
);
3754 if ((unsigned)event_cpu
>= nr_cpu_ids
)
3758 event_cpu
= __perf_event_read_cpu(event
, event_cpu
);
3761 * Purposely ignore the smp_call_function_single() return
3764 * If event_cpu isn't a valid CPU it means the event got
3765 * scheduled out and that will have updated the event count.
3767 * Therefore, either way, we'll have an up-to-date event count
3770 (void)smp_call_function_single(event_cpu
, __perf_event_read
, &data
, 1);
3773 } else if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
3774 struct perf_event_context
*ctx
= event
->ctx
;
3775 unsigned long flags
;
3777 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
3779 * may read while context is not active
3780 * (e.g., thread is blocked), in that case
3781 * we cannot update context time
3783 if (ctx
->is_active
) {
3784 update_context_time(ctx
);
3785 update_cgrp_time_from_event(event
);
3788 update_group_times(event
);
3790 update_event_times(event
);
3791 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
3798 * Initialize the perf_event context in a task_struct:
3800 static void __perf_event_init_context(struct perf_event_context
*ctx
)
3802 raw_spin_lock_init(&ctx
->lock
);
3803 mutex_init(&ctx
->mutex
);
3804 INIT_LIST_HEAD(&ctx
->active_ctx_list
);
3805 INIT_LIST_HEAD(&ctx
->pinned_groups
);
3806 INIT_LIST_HEAD(&ctx
->flexible_groups
);
3807 INIT_LIST_HEAD(&ctx
->event_list
);
3808 atomic_set(&ctx
->refcount
, 1);
3811 static struct perf_event_context
*
3812 alloc_perf_context(struct pmu
*pmu
, struct task_struct
*task
)
3814 struct perf_event_context
*ctx
;
3816 ctx
= kzalloc(sizeof(struct perf_event_context
), GFP_KERNEL
);
3820 __perf_event_init_context(ctx
);
3823 get_task_struct(task
);
3830 static struct task_struct
*
3831 find_lively_task_by_vpid(pid_t vpid
)
3833 struct task_struct
*task
;
3839 task
= find_task_by_vpid(vpid
);
3841 get_task_struct(task
);
3845 return ERR_PTR(-ESRCH
);
3851 * Returns a matching context with refcount and pincount.
3853 static struct perf_event_context
*
3854 find_get_context(struct pmu
*pmu
, struct task_struct
*task
,
3855 struct perf_event
*event
)
3857 struct perf_event_context
*ctx
, *clone_ctx
= NULL
;
3858 struct perf_cpu_context
*cpuctx
;
3859 void *task_ctx_data
= NULL
;
3860 unsigned long flags
;
3862 int cpu
= event
->cpu
;
3865 /* Must be root to operate on a CPU event: */
3866 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN
))
3867 return ERR_PTR(-EACCES
);
3869 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
3878 ctxn
= pmu
->task_ctx_nr
;
3882 if (event
->attach_state
& PERF_ATTACH_TASK_DATA
) {
3883 task_ctx_data
= kzalloc(pmu
->task_ctx_size
, GFP_KERNEL
);
3884 if (!task_ctx_data
) {
3891 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
3893 clone_ctx
= unclone_ctx(ctx
);
3896 if (task_ctx_data
&& !ctx
->task_ctx_data
) {
3897 ctx
->task_ctx_data
= task_ctx_data
;
3898 task_ctx_data
= NULL
;
3900 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
3905 ctx
= alloc_perf_context(pmu
, task
);
3910 if (task_ctx_data
) {
3911 ctx
->task_ctx_data
= task_ctx_data
;
3912 task_ctx_data
= NULL
;
3916 mutex_lock(&task
->perf_event_mutex
);
3918 * If it has already passed perf_event_exit_task().
3919 * we must see PF_EXITING, it takes this mutex too.
3921 if (task
->flags
& PF_EXITING
)
3923 else if (task
->perf_event_ctxp
[ctxn
])
3928 rcu_assign_pointer(task
->perf_event_ctxp
[ctxn
], ctx
);
3930 mutex_unlock(&task
->perf_event_mutex
);
3932 if (unlikely(err
)) {
3941 kfree(task_ctx_data
);
3945 kfree(task_ctx_data
);
3946 return ERR_PTR(err
);
3949 static void perf_event_free_filter(struct perf_event
*event
);
3950 static void perf_event_free_bpf_prog(struct perf_event
*event
);
3952 static void free_event_rcu(struct rcu_head
*head
)
3954 struct perf_event
*event
;
3956 event
= container_of(head
, struct perf_event
, rcu_head
);
3958 put_pid_ns(event
->ns
);
3959 perf_event_free_filter(event
);
3963 static void ring_buffer_attach(struct perf_event
*event
,
3964 struct ring_buffer
*rb
);
3966 static void detach_sb_event(struct perf_event
*event
)
3968 struct pmu_event_list
*pel
= per_cpu_ptr(&pmu_sb_events
, event
->cpu
);
3970 raw_spin_lock(&pel
->lock
);
3971 list_del_rcu(&event
->sb_list
);
3972 raw_spin_unlock(&pel
->lock
);
3975 static bool is_sb_event(struct perf_event
*event
)
3977 struct perf_event_attr
*attr
= &event
->attr
;
3982 if (event
->attach_state
& PERF_ATTACH_TASK
)
3985 if (attr
->mmap
|| attr
->mmap_data
|| attr
->mmap2
||
3986 attr
->comm
|| attr
->comm_exec
||
3988 attr
->context_switch
)
3993 static void unaccount_pmu_sb_event(struct perf_event
*event
)
3995 if (is_sb_event(event
))
3996 detach_sb_event(event
);
3999 static void unaccount_event_cpu(struct perf_event
*event
, int cpu
)
4004 if (is_cgroup_event(event
))
4005 atomic_dec(&per_cpu(perf_cgroup_events
, cpu
));
4008 #ifdef CONFIG_NO_HZ_FULL
4009 static DEFINE_SPINLOCK(nr_freq_lock
);
4012 static void unaccount_freq_event_nohz(void)
4014 #ifdef CONFIG_NO_HZ_FULL
4015 spin_lock(&nr_freq_lock
);
4016 if (atomic_dec_and_test(&nr_freq_events
))
4017 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS
);
4018 spin_unlock(&nr_freq_lock
);
4022 static void unaccount_freq_event(void)
4024 if (tick_nohz_full_enabled())
4025 unaccount_freq_event_nohz();
4027 atomic_dec(&nr_freq_events
);
4030 static void unaccount_event(struct perf_event
*event
)
4037 if (event
->attach_state
& PERF_ATTACH_TASK
)
4039 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
4040 atomic_dec(&nr_mmap_events
);
4041 if (event
->attr
.comm
)
4042 atomic_dec(&nr_comm_events
);
4043 if (event
->attr
.namespaces
)
4044 atomic_dec(&nr_namespaces_events
);
4045 if (event
->attr
.task
)
4046 atomic_dec(&nr_task_events
);
4047 if (event
->attr
.freq
)
4048 unaccount_freq_event();
4049 if (event
->attr
.context_switch
) {
4051 atomic_dec(&nr_switch_events
);
4053 if (is_cgroup_event(event
))
4055 if (has_branch_stack(event
))
4059 if (!atomic_add_unless(&perf_sched_count
, -1, 1))
4060 schedule_delayed_work(&perf_sched_work
, HZ
);
4063 unaccount_event_cpu(event
, event
->cpu
);
4065 unaccount_pmu_sb_event(event
);
4068 static void perf_sched_delayed(struct work_struct
*work
)
4070 mutex_lock(&perf_sched_mutex
);
4071 if (atomic_dec_and_test(&perf_sched_count
))
4072 static_branch_disable(&perf_sched_events
);
4073 mutex_unlock(&perf_sched_mutex
);
4077 * The following implement mutual exclusion of events on "exclusive" pmus
4078 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4079 * at a time, so we disallow creating events that might conflict, namely:
4081 * 1) cpu-wide events in the presence of per-task events,
4082 * 2) per-task events in the presence of cpu-wide events,
4083 * 3) two matching events on the same context.
4085 * The former two cases are handled in the allocation path (perf_event_alloc(),
4086 * _free_event()), the latter -- before the first perf_install_in_context().
4088 static int exclusive_event_init(struct perf_event
*event
)
4090 struct pmu
*pmu
= event
->pmu
;
4092 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
4096 * Prevent co-existence of per-task and cpu-wide events on the
4097 * same exclusive pmu.
4099 * Negative pmu::exclusive_cnt means there are cpu-wide
4100 * events on this "exclusive" pmu, positive means there are
4103 * Since this is called in perf_event_alloc() path, event::ctx
4104 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4105 * to mean "per-task event", because unlike other attach states it
4106 * never gets cleared.
4108 if (event
->attach_state
& PERF_ATTACH_TASK
) {
4109 if (!atomic_inc_unless_negative(&pmu
->exclusive_cnt
))
4112 if (!atomic_dec_unless_positive(&pmu
->exclusive_cnt
))
4119 static void exclusive_event_destroy(struct perf_event
*event
)
4121 struct pmu
*pmu
= event
->pmu
;
4123 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
4126 /* see comment in exclusive_event_init() */
4127 if (event
->attach_state
& PERF_ATTACH_TASK
)
4128 atomic_dec(&pmu
->exclusive_cnt
);
4130 atomic_inc(&pmu
->exclusive_cnt
);
4133 static bool exclusive_event_match(struct perf_event
*e1
, struct perf_event
*e2
)
4135 if ((e1
->pmu
== e2
->pmu
) &&
4136 (e1
->cpu
== e2
->cpu
||
4143 /* Called under the same ctx::mutex as perf_install_in_context() */
4144 static bool exclusive_event_installable(struct perf_event
*event
,
4145 struct perf_event_context
*ctx
)
4147 struct perf_event
*iter_event
;
4148 struct pmu
*pmu
= event
->pmu
;
4150 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
4153 list_for_each_entry(iter_event
, &ctx
->event_list
, event_entry
) {
4154 if (exclusive_event_match(iter_event
, event
))
4161 static void perf_addr_filters_splice(struct perf_event
*event
,
4162 struct list_head
*head
);
4164 static void _free_event(struct perf_event
*event
)
4166 irq_work_sync(&event
->pending
);
4168 unaccount_event(event
);
4172 * Can happen when we close an event with re-directed output.
4174 * Since we have a 0 refcount, perf_mmap_close() will skip
4175 * over us; possibly making our ring_buffer_put() the last.
4177 mutex_lock(&event
->mmap_mutex
);
4178 ring_buffer_attach(event
, NULL
);
4179 mutex_unlock(&event
->mmap_mutex
);
4182 if (is_cgroup_event(event
))
4183 perf_detach_cgroup(event
);
4185 if (!event
->parent
) {
4186 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
)
4187 put_callchain_buffers();
4190 perf_event_free_bpf_prog(event
);
4191 perf_addr_filters_splice(event
, NULL
);
4192 kfree(event
->addr_filters_offs
);
4195 event
->destroy(event
);
4198 put_ctx(event
->ctx
);
4200 exclusive_event_destroy(event
);
4201 module_put(event
->pmu
->module
);
4203 call_rcu(&event
->rcu_head
, free_event_rcu
);
4207 * Used to free events which have a known refcount of 1, such as in error paths
4208 * where the event isn't exposed yet and inherited events.
4210 static void free_event(struct perf_event
*event
)
4212 if (WARN(atomic_long_cmpxchg(&event
->refcount
, 1, 0) != 1,
4213 "unexpected event refcount: %ld; ptr=%p\n",
4214 atomic_long_read(&event
->refcount
), event
)) {
4215 /* leak to avoid use-after-free */
4223 * Remove user event from the owner task.
4225 static void perf_remove_from_owner(struct perf_event
*event
)
4227 struct task_struct
*owner
;
4231 * Matches the smp_store_release() in perf_event_exit_task(). If we
4232 * observe !owner it means the list deletion is complete and we can
4233 * indeed free this event, otherwise we need to serialize on
4234 * owner->perf_event_mutex.
4236 owner
= READ_ONCE(event
->owner
);
4239 * Since delayed_put_task_struct() also drops the last
4240 * task reference we can safely take a new reference
4241 * while holding the rcu_read_lock().
4243 get_task_struct(owner
);
4249 * If we're here through perf_event_exit_task() we're already
4250 * holding ctx->mutex which would be an inversion wrt. the
4251 * normal lock order.
4253 * However we can safely take this lock because its the child
4256 mutex_lock_nested(&owner
->perf_event_mutex
, SINGLE_DEPTH_NESTING
);
4259 * We have to re-check the event->owner field, if it is cleared
4260 * we raced with perf_event_exit_task(), acquiring the mutex
4261 * ensured they're done, and we can proceed with freeing the
4265 list_del_init(&event
->owner_entry
);
4266 smp_store_release(&event
->owner
, NULL
);
4268 mutex_unlock(&owner
->perf_event_mutex
);
4269 put_task_struct(owner
);
4273 static void put_event(struct perf_event
*event
)
4275 if (!atomic_long_dec_and_test(&event
->refcount
))
4282 * Kill an event dead; while event:refcount will preserve the event
4283 * object, it will not preserve its functionality. Once the last 'user'
4284 * gives up the object, we'll destroy the thing.
4286 int perf_event_release_kernel(struct perf_event
*event
)
4288 struct perf_event_context
*ctx
= event
->ctx
;
4289 struct perf_event
*child
, *tmp
;
4292 * If we got here through err_file: fput(event_file); we will not have
4293 * attached to a context yet.
4296 WARN_ON_ONCE(event
->attach_state
&
4297 (PERF_ATTACH_CONTEXT
|PERF_ATTACH_GROUP
));
4301 if (!is_kernel_event(event
))
4302 perf_remove_from_owner(event
);
4304 ctx
= perf_event_ctx_lock(event
);
4305 WARN_ON_ONCE(ctx
->parent_ctx
);
4306 perf_remove_from_context(event
, DETACH_GROUP
);
4308 raw_spin_lock_irq(&ctx
->lock
);
4310 * Mark this event as STATE_DEAD, there is no external reference to it
4313 * Anybody acquiring event->child_mutex after the below loop _must_
4314 * also see this, most importantly inherit_event() which will avoid
4315 * placing more children on the list.
4317 * Thus this guarantees that we will in fact observe and kill _ALL_
4320 event
->state
= PERF_EVENT_STATE_DEAD
;
4321 raw_spin_unlock_irq(&ctx
->lock
);
4323 perf_event_ctx_unlock(event
, ctx
);
4326 mutex_lock(&event
->child_mutex
);
4327 list_for_each_entry(child
, &event
->child_list
, child_list
) {
4330 * Cannot change, child events are not migrated, see the
4331 * comment with perf_event_ctx_lock_nested().
4333 ctx
= READ_ONCE(child
->ctx
);
4335 * Since child_mutex nests inside ctx::mutex, we must jump
4336 * through hoops. We start by grabbing a reference on the ctx.
4338 * Since the event cannot get freed while we hold the
4339 * child_mutex, the context must also exist and have a !0
4345 * Now that we have a ctx ref, we can drop child_mutex, and
4346 * acquire ctx::mutex without fear of it going away. Then we
4347 * can re-acquire child_mutex.
4349 mutex_unlock(&event
->child_mutex
);
4350 mutex_lock(&ctx
->mutex
);
4351 mutex_lock(&event
->child_mutex
);
4354 * Now that we hold ctx::mutex and child_mutex, revalidate our
4355 * state, if child is still the first entry, it didn't get freed
4356 * and we can continue doing so.
4358 tmp
= list_first_entry_or_null(&event
->child_list
,
4359 struct perf_event
, child_list
);
4361 perf_remove_from_context(child
, DETACH_GROUP
);
4362 list_del(&child
->child_list
);
4365 * This matches the refcount bump in inherit_event();
4366 * this can't be the last reference.
4371 mutex_unlock(&event
->child_mutex
);
4372 mutex_unlock(&ctx
->mutex
);
4376 mutex_unlock(&event
->child_mutex
);
4379 put_event(event
); /* Must be the 'last' reference */
4382 EXPORT_SYMBOL_GPL(perf_event_release_kernel
);
4385 * Called when the last reference to the file is gone.
4387 static int perf_release(struct inode
*inode
, struct file
*file
)
4389 perf_event_release_kernel(file
->private_data
);
4393 u64
perf_event_read_value(struct perf_event
*event
, u64
*enabled
, u64
*running
)
4395 struct perf_event
*child
;
4401 mutex_lock(&event
->child_mutex
);
4403 (void)perf_event_read(event
, false);
4404 total
+= perf_event_count(event
);
4406 *enabled
+= event
->total_time_enabled
+
4407 atomic64_read(&event
->child_total_time_enabled
);
4408 *running
+= event
->total_time_running
+
4409 atomic64_read(&event
->child_total_time_running
);
4411 list_for_each_entry(child
, &event
->child_list
, child_list
) {
4412 (void)perf_event_read(child
, false);
4413 total
+= perf_event_count(child
);
4414 *enabled
+= child
->total_time_enabled
;
4415 *running
+= child
->total_time_running
;
4417 mutex_unlock(&event
->child_mutex
);
4421 EXPORT_SYMBOL_GPL(perf_event_read_value
);
4423 static int __perf_read_group_add(struct perf_event
*leader
,
4424 u64 read_format
, u64
*values
)
4426 struct perf_event_context
*ctx
= leader
->ctx
;
4427 struct perf_event
*sub
;
4428 unsigned long flags
;
4429 int n
= 1; /* skip @nr */
4432 ret
= perf_event_read(leader
, true);
4437 * Since we co-schedule groups, {enabled,running} times of siblings
4438 * will be identical to those of the leader, so we only publish one
4441 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
4442 values
[n
++] += leader
->total_time_enabled
+
4443 atomic64_read(&leader
->child_total_time_enabled
);
4446 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
4447 values
[n
++] += leader
->total_time_running
+
4448 atomic64_read(&leader
->child_total_time_running
);
4452 * Write {count,id} tuples for every sibling.
4454 values
[n
++] += perf_event_count(leader
);
4455 if (read_format
& PERF_FORMAT_ID
)
4456 values
[n
++] = primary_event_id(leader
);
4458 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
4460 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
4461 values
[n
++] += perf_event_count(sub
);
4462 if (read_format
& PERF_FORMAT_ID
)
4463 values
[n
++] = primary_event_id(sub
);
4466 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
4470 static int perf_read_group(struct perf_event
*event
,
4471 u64 read_format
, char __user
*buf
)
4473 struct perf_event
*leader
= event
->group_leader
, *child
;
4474 struct perf_event_context
*ctx
= leader
->ctx
;
4478 lockdep_assert_held(&ctx
->mutex
);
4480 values
= kzalloc(event
->read_size
, GFP_KERNEL
);
4484 values
[0] = 1 + leader
->nr_siblings
;
4487 * By locking the child_mutex of the leader we effectively
4488 * lock the child list of all siblings.. XXX explain how.
4490 mutex_lock(&leader
->child_mutex
);
4492 ret
= __perf_read_group_add(leader
, read_format
, values
);
4496 list_for_each_entry(child
, &leader
->child_list
, child_list
) {
4497 ret
= __perf_read_group_add(child
, read_format
, values
);
4502 mutex_unlock(&leader
->child_mutex
);
4504 ret
= event
->read_size
;
4505 if (copy_to_user(buf
, values
, event
->read_size
))
4510 mutex_unlock(&leader
->child_mutex
);
4516 static int perf_read_one(struct perf_event
*event
,
4517 u64 read_format
, char __user
*buf
)
4519 u64 enabled
, running
;
4523 values
[n
++] = perf_event_read_value(event
, &enabled
, &running
);
4524 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
4525 values
[n
++] = enabled
;
4526 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
4527 values
[n
++] = running
;
4528 if (read_format
& PERF_FORMAT_ID
)
4529 values
[n
++] = primary_event_id(event
);
4531 if (copy_to_user(buf
, values
, n
* sizeof(u64
)))
4534 return n
* sizeof(u64
);
4537 static bool is_event_hup(struct perf_event
*event
)
4541 if (event
->state
> PERF_EVENT_STATE_EXIT
)
4544 mutex_lock(&event
->child_mutex
);
4545 no_children
= list_empty(&event
->child_list
);
4546 mutex_unlock(&event
->child_mutex
);
4551 * Read the performance event - simple non blocking version for now
4554 __perf_read(struct perf_event
*event
, char __user
*buf
, size_t count
)
4556 u64 read_format
= event
->attr
.read_format
;
4560 * Return end-of-file for a read on a event that is in
4561 * error state (i.e. because it was pinned but it couldn't be
4562 * scheduled on to the CPU at some point).
4564 if (event
->state
== PERF_EVENT_STATE_ERROR
)
4567 if (count
< event
->read_size
)
4570 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
4571 if (read_format
& PERF_FORMAT_GROUP
)
4572 ret
= perf_read_group(event
, read_format
, buf
);
4574 ret
= perf_read_one(event
, read_format
, buf
);
4580 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
4582 struct perf_event
*event
= file
->private_data
;
4583 struct perf_event_context
*ctx
;
4586 ctx
= perf_event_ctx_lock(event
);
4587 ret
= __perf_read(event
, buf
, count
);
4588 perf_event_ctx_unlock(event
, ctx
);
4593 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
4595 struct perf_event
*event
= file
->private_data
;
4596 struct ring_buffer
*rb
;
4597 unsigned int events
= POLLHUP
;
4599 poll_wait(file
, &event
->waitq
, wait
);
4601 if (is_event_hup(event
))
4605 * Pin the event->rb by taking event->mmap_mutex; otherwise
4606 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4608 mutex_lock(&event
->mmap_mutex
);
4611 events
= atomic_xchg(&rb
->poll
, 0);
4612 mutex_unlock(&event
->mmap_mutex
);
4616 static void _perf_event_reset(struct perf_event
*event
)
4618 (void)perf_event_read(event
, false);
4619 local64_set(&event
->count
, 0);
4620 perf_event_update_userpage(event
);
4624 * Holding the top-level event's child_mutex means that any
4625 * descendant process that has inherited this event will block
4626 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4627 * task existence requirements of perf_event_enable/disable.
4629 static void perf_event_for_each_child(struct perf_event
*event
,
4630 void (*func
)(struct perf_event
*))
4632 struct perf_event
*child
;
4634 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
4636 mutex_lock(&event
->child_mutex
);
4638 list_for_each_entry(child
, &event
->child_list
, child_list
)
4640 mutex_unlock(&event
->child_mutex
);
4643 static void perf_event_for_each(struct perf_event
*event
,
4644 void (*func
)(struct perf_event
*))
4646 struct perf_event_context
*ctx
= event
->ctx
;
4647 struct perf_event
*sibling
;
4649 lockdep_assert_held(&ctx
->mutex
);
4651 event
= event
->group_leader
;
4653 perf_event_for_each_child(event
, func
);
4654 list_for_each_entry(sibling
, &event
->sibling_list
, group_entry
)
4655 perf_event_for_each_child(sibling
, func
);
4658 static void __perf_event_period(struct perf_event
*event
,
4659 struct perf_cpu_context
*cpuctx
,
4660 struct perf_event_context
*ctx
,
4663 u64 value
= *((u64
*)info
);
4666 if (event
->attr
.freq
) {
4667 event
->attr
.sample_freq
= value
;
4669 event
->attr
.sample_period
= value
;
4670 event
->hw
.sample_period
= value
;
4673 active
= (event
->state
== PERF_EVENT_STATE_ACTIVE
);
4675 perf_pmu_disable(ctx
->pmu
);
4677 * We could be throttled; unthrottle now to avoid the tick
4678 * trying to unthrottle while we already re-started the event.
4680 if (event
->hw
.interrupts
== MAX_INTERRUPTS
) {
4681 event
->hw
.interrupts
= 0;
4682 perf_log_throttle(event
, 1);
4684 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
4687 local64_set(&event
->hw
.period_left
, 0);
4690 event
->pmu
->start(event
, PERF_EF_RELOAD
);
4691 perf_pmu_enable(ctx
->pmu
);
4695 static int perf_event_period(struct perf_event
*event
, u64 __user
*arg
)
4699 if (!is_sampling_event(event
))
4702 if (copy_from_user(&value
, arg
, sizeof(value
)))
4708 if (event
->attr
.freq
&& value
> sysctl_perf_event_sample_rate
)
4711 event_function_call(event
, __perf_event_period
, &value
);
4716 static const struct file_operations perf_fops
;
4718 static inline int perf_fget_light(int fd
, struct fd
*p
)
4720 struct fd f
= fdget(fd
);
4724 if (f
.file
->f_op
!= &perf_fops
) {
4732 static int perf_event_set_output(struct perf_event
*event
,
4733 struct perf_event
*output_event
);
4734 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
);
4735 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
);
4737 static long _perf_ioctl(struct perf_event
*event
, unsigned int cmd
, unsigned long arg
)
4739 void (*func
)(struct perf_event
*);
4743 case PERF_EVENT_IOC_ENABLE
:
4744 func
= _perf_event_enable
;
4746 case PERF_EVENT_IOC_DISABLE
:
4747 func
= _perf_event_disable
;
4749 case PERF_EVENT_IOC_RESET
:
4750 func
= _perf_event_reset
;
4753 case PERF_EVENT_IOC_REFRESH
:
4754 return _perf_event_refresh(event
, arg
);
4756 case PERF_EVENT_IOC_PERIOD
:
4757 return perf_event_period(event
, (u64 __user
*)arg
);
4759 case PERF_EVENT_IOC_ID
:
4761 u64 id
= primary_event_id(event
);
4763 if (copy_to_user((void __user
*)arg
, &id
, sizeof(id
)))
4768 case PERF_EVENT_IOC_SET_OUTPUT
:
4772 struct perf_event
*output_event
;
4774 ret
= perf_fget_light(arg
, &output
);
4777 output_event
= output
.file
->private_data
;
4778 ret
= perf_event_set_output(event
, output_event
);
4781 ret
= perf_event_set_output(event
, NULL
);
4786 case PERF_EVENT_IOC_SET_FILTER
:
4787 return perf_event_set_filter(event
, (void __user
*)arg
);
4789 case PERF_EVENT_IOC_SET_BPF
:
4790 return perf_event_set_bpf_prog(event
, arg
);
4792 case PERF_EVENT_IOC_PAUSE_OUTPUT
: {
4793 struct ring_buffer
*rb
;
4796 rb
= rcu_dereference(event
->rb
);
4797 if (!rb
|| !rb
->nr_pages
) {
4801 rb_toggle_paused(rb
, !!arg
);
4809 if (flags
& PERF_IOC_FLAG_GROUP
)
4810 perf_event_for_each(event
, func
);
4812 perf_event_for_each_child(event
, func
);
4817 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
4819 struct perf_event
*event
= file
->private_data
;
4820 struct perf_event_context
*ctx
;
4823 ctx
= perf_event_ctx_lock(event
);
4824 ret
= _perf_ioctl(event
, cmd
, arg
);
4825 perf_event_ctx_unlock(event
, ctx
);
4830 #ifdef CONFIG_COMPAT
4831 static long perf_compat_ioctl(struct file
*file
, unsigned int cmd
,
4834 switch (_IOC_NR(cmd
)) {
4835 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER
):
4836 case _IOC_NR(PERF_EVENT_IOC_ID
):
4837 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4838 if (_IOC_SIZE(cmd
) == sizeof(compat_uptr_t
)) {
4839 cmd
&= ~IOCSIZE_MASK
;
4840 cmd
|= sizeof(void *) << IOCSIZE_SHIFT
;
4844 return perf_ioctl(file
, cmd
, arg
);
4847 # define perf_compat_ioctl NULL
4850 int perf_event_task_enable(void)
4852 struct perf_event_context
*ctx
;
4853 struct perf_event
*event
;
4855 mutex_lock(¤t
->perf_event_mutex
);
4856 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
) {
4857 ctx
= perf_event_ctx_lock(event
);
4858 perf_event_for_each_child(event
, _perf_event_enable
);
4859 perf_event_ctx_unlock(event
, ctx
);
4861 mutex_unlock(¤t
->perf_event_mutex
);
4866 int perf_event_task_disable(void)
4868 struct perf_event_context
*ctx
;
4869 struct perf_event
*event
;
4871 mutex_lock(¤t
->perf_event_mutex
);
4872 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
) {
4873 ctx
= perf_event_ctx_lock(event
);
4874 perf_event_for_each_child(event
, _perf_event_disable
);
4875 perf_event_ctx_unlock(event
, ctx
);
4877 mutex_unlock(¤t
->perf_event_mutex
);
4882 static int perf_event_index(struct perf_event
*event
)
4884 if (event
->hw
.state
& PERF_HES_STOPPED
)
4887 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
4890 return event
->pmu
->event_idx(event
);
4893 static void calc_timer_values(struct perf_event
*event
,
4900 *now
= perf_clock();
4901 ctx_time
= event
->shadow_ctx_time
+ *now
;
4902 *enabled
= ctx_time
- event
->tstamp_enabled
;
4903 *running
= ctx_time
- event
->tstamp_running
;
4906 static void perf_event_init_userpage(struct perf_event
*event
)
4908 struct perf_event_mmap_page
*userpg
;
4909 struct ring_buffer
*rb
;
4912 rb
= rcu_dereference(event
->rb
);
4916 userpg
= rb
->user_page
;
4918 /* Allow new userspace to detect that bit 0 is deprecated */
4919 userpg
->cap_bit0_is_deprecated
= 1;
4920 userpg
->size
= offsetof(struct perf_event_mmap_page
, __reserved
);
4921 userpg
->data_offset
= PAGE_SIZE
;
4922 userpg
->data_size
= perf_data_size(rb
);
4928 void __weak
arch_perf_update_userpage(
4929 struct perf_event
*event
, struct perf_event_mmap_page
*userpg
, u64 now
)
4934 * Callers need to ensure there can be no nesting of this function, otherwise
4935 * the seqlock logic goes bad. We can not serialize this because the arch
4936 * code calls this from NMI context.
4938 void perf_event_update_userpage(struct perf_event
*event
)
4940 struct perf_event_mmap_page
*userpg
;
4941 struct ring_buffer
*rb
;
4942 u64 enabled
, running
, now
;
4945 rb
= rcu_dereference(event
->rb
);
4950 * compute total_time_enabled, total_time_running
4951 * based on snapshot values taken when the event
4952 * was last scheduled in.
4954 * we cannot simply called update_context_time()
4955 * because of locking issue as we can be called in
4958 calc_timer_values(event
, &now
, &enabled
, &running
);
4960 userpg
= rb
->user_page
;
4962 * Disable preemption so as to not let the corresponding user-space
4963 * spin too long if we get preempted.
4968 userpg
->index
= perf_event_index(event
);
4969 userpg
->offset
= perf_event_count(event
);
4971 userpg
->offset
-= local64_read(&event
->hw
.prev_count
);
4973 userpg
->time_enabled
= enabled
+
4974 atomic64_read(&event
->child_total_time_enabled
);
4976 userpg
->time_running
= running
+
4977 atomic64_read(&event
->child_total_time_running
);
4979 arch_perf_update_userpage(event
, userpg
, now
);
4988 static int perf_mmap_fault(struct vm_fault
*vmf
)
4990 struct perf_event
*event
= vmf
->vma
->vm_file
->private_data
;
4991 struct ring_buffer
*rb
;
4992 int ret
= VM_FAULT_SIGBUS
;
4994 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
4995 if (vmf
->pgoff
== 0)
5001 rb
= rcu_dereference(event
->rb
);
5005 if (vmf
->pgoff
&& (vmf
->flags
& FAULT_FLAG_WRITE
))
5008 vmf
->page
= perf_mmap_to_page(rb
, vmf
->pgoff
);
5012 get_page(vmf
->page
);
5013 vmf
->page
->mapping
= vmf
->vma
->vm_file
->f_mapping
;
5014 vmf
->page
->index
= vmf
->pgoff
;
5023 static void ring_buffer_attach(struct perf_event
*event
,
5024 struct ring_buffer
*rb
)
5026 struct ring_buffer
*old_rb
= NULL
;
5027 unsigned long flags
;
5031 * Should be impossible, we set this when removing
5032 * event->rb_entry and wait/clear when adding event->rb_entry.
5034 WARN_ON_ONCE(event
->rcu_pending
);
5037 spin_lock_irqsave(&old_rb
->event_lock
, flags
);
5038 list_del_rcu(&event
->rb_entry
);
5039 spin_unlock_irqrestore(&old_rb
->event_lock
, flags
);
5041 event
->rcu_batches
= get_state_synchronize_rcu();
5042 event
->rcu_pending
= 1;
5046 if (event
->rcu_pending
) {
5047 cond_synchronize_rcu(event
->rcu_batches
);
5048 event
->rcu_pending
= 0;
5051 spin_lock_irqsave(&rb
->event_lock
, flags
);
5052 list_add_rcu(&event
->rb_entry
, &rb
->event_list
);
5053 spin_unlock_irqrestore(&rb
->event_lock
, flags
);
5057 * Avoid racing with perf_mmap_close(AUX): stop the event
5058 * before swizzling the event::rb pointer; if it's getting
5059 * unmapped, its aux_mmap_count will be 0 and it won't
5060 * restart. See the comment in __perf_pmu_output_stop().
5062 * Data will inevitably be lost when set_output is done in
5063 * mid-air, but then again, whoever does it like this is
5064 * not in for the data anyway.
5067 perf_event_stop(event
, 0);
5069 rcu_assign_pointer(event
->rb
, rb
);
5072 ring_buffer_put(old_rb
);
5074 * Since we detached before setting the new rb, so that we
5075 * could attach the new rb, we could have missed a wakeup.
5078 wake_up_all(&event
->waitq
);
5082 static void ring_buffer_wakeup(struct perf_event
*event
)
5084 struct ring_buffer
*rb
;
5087 rb
= rcu_dereference(event
->rb
);
5089 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
)
5090 wake_up_all(&event
->waitq
);
5095 struct ring_buffer
*ring_buffer_get(struct perf_event
*event
)
5097 struct ring_buffer
*rb
;
5100 rb
= rcu_dereference(event
->rb
);
5102 if (!atomic_inc_not_zero(&rb
->refcount
))
5110 void ring_buffer_put(struct ring_buffer
*rb
)
5112 if (!atomic_dec_and_test(&rb
->refcount
))
5115 WARN_ON_ONCE(!list_empty(&rb
->event_list
));
5117 call_rcu(&rb
->rcu_head
, rb_free_rcu
);
5120 static void perf_mmap_open(struct vm_area_struct
*vma
)
5122 struct perf_event
*event
= vma
->vm_file
->private_data
;
5124 atomic_inc(&event
->mmap_count
);
5125 atomic_inc(&event
->rb
->mmap_count
);
5128 atomic_inc(&event
->rb
->aux_mmap_count
);
5130 if (event
->pmu
->event_mapped
)
5131 event
->pmu
->event_mapped(event
, vma
->vm_mm
);
5134 static void perf_pmu_output_stop(struct perf_event
*event
);
5137 * A buffer can be mmap()ed multiple times; either directly through the same
5138 * event, or through other events by use of perf_event_set_output().
5140 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5141 * the buffer here, where we still have a VM context. This means we need
5142 * to detach all events redirecting to us.
5144 static void perf_mmap_close(struct vm_area_struct
*vma
)
5146 struct perf_event
*event
= vma
->vm_file
->private_data
;
5148 struct ring_buffer
*rb
= ring_buffer_get(event
);
5149 struct user_struct
*mmap_user
= rb
->mmap_user
;
5150 int mmap_locked
= rb
->mmap_locked
;
5151 unsigned long size
= perf_data_size(rb
);
5153 if (event
->pmu
->event_unmapped
)
5154 event
->pmu
->event_unmapped(event
, vma
->vm_mm
);
5157 * rb->aux_mmap_count will always drop before rb->mmap_count and
5158 * event->mmap_count, so it is ok to use event->mmap_mutex to
5159 * serialize with perf_mmap here.
5161 if (rb_has_aux(rb
) && vma
->vm_pgoff
== rb
->aux_pgoff
&&
5162 atomic_dec_and_mutex_lock(&rb
->aux_mmap_count
, &event
->mmap_mutex
)) {
5164 * Stop all AUX events that are writing to this buffer,
5165 * so that we can free its AUX pages and corresponding PMU
5166 * data. Note that after rb::aux_mmap_count dropped to zero,
5167 * they won't start any more (see perf_aux_output_begin()).
5169 perf_pmu_output_stop(event
);
5171 /* now it's safe to free the pages */
5172 atomic_long_sub(rb
->aux_nr_pages
, &mmap_user
->locked_vm
);
5173 vma
->vm_mm
->pinned_vm
-= rb
->aux_mmap_locked
;
5175 /* this has to be the last one */
5177 WARN_ON_ONCE(atomic_read(&rb
->aux_refcount
));
5179 mutex_unlock(&event
->mmap_mutex
);
5182 atomic_dec(&rb
->mmap_count
);
5184 if (!atomic_dec_and_mutex_lock(&event
->mmap_count
, &event
->mmap_mutex
))
5187 ring_buffer_attach(event
, NULL
);
5188 mutex_unlock(&event
->mmap_mutex
);
5190 /* If there's still other mmap()s of this buffer, we're done. */
5191 if (atomic_read(&rb
->mmap_count
))
5195 * No other mmap()s, detach from all other events that might redirect
5196 * into the now unreachable buffer. Somewhat complicated by the
5197 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5201 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
) {
5202 if (!atomic_long_inc_not_zero(&event
->refcount
)) {
5204 * This event is en-route to free_event() which will
5205 * detach it and remove it from the list.
5211 mutex_lock(&event
->mmap_mutex
);
5213 * Check we didn't race with perf_event_set_output() which can
5214 * swizzle the rb from under us while we were waiting to
5215 * acquire mmap_mutex.
5217 * If we find a different rb; ignore this event, a next
5218 * iteration will no longer find it on the list. We have to
5219 * still restart the iteration to make sure we're not now
5220 * iterating the wrong list.
5222 if (event
->rb
== rb
)
5223 ring_buffer_attach(event
, NULL
);
5225 mutex_unlock(&event
->mmap_mutex
);
5229 * Restart the iteration; either we're on the wrong list or
5230 * destroyed its integrity by doing a deletion.
5237 * It could be there's still a few 0-ref events on the list; they'll
5238 * get cleaned up by free_event() -- they'll also still have their
5239 * ref on the rb and will free it whenever they are done with it.
5241 * Aside from that, this buffer is 'fully' detached and unmapped,
5242 * undo the VM accounting.
5245 atomic_long_sub((size
>> PAGE_SHIFT
) + 1, &mmap_user
->locked_vm
);
5246 vma
->vm_mm
->pinned_vm
-= mmap_locked
;
5247 free_uid(mmap_user
);
5250 ring_buffer_put(rb
); /* could be last */
5253 static const struct vm_operations_struct perf_mmap_vmops
= {
5254 .open
= perf_mmap_open
,
5255 .close
= perf_mmap_close
, /* non mergable */
5256 .fault
= perf_mmap_fault
,
5257 .page_mkwrite
= perf_mmap_fault
,
5260 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
5262 struct perf_event
*event
= file
->private_data
;
5263 unsigned long user_locked
, user_lock_limit
;
5264 struct user_struct
*user
= current_user();
5265 unsigned long locked
, lock_limit
;
5266 struct ring_buffer
*rb
= NULL
;
5267 unsigned long vma_size
;
5268 unsigned long nr_pages
;
5269 long user_extra
= 0, extra
= 0;
5270 int ret
= 0, flags
= 0;
5273 * Don't allow mmap() of inherited per-task counters. This would
5274 * create a performance issue due to all children writing to the
5277 if (event
->cpu
== -1 && event
->attr
.inherit
)
5280 if (!(vma
->vm_flags
& VM_SHARED
))
5283 vma_size
= vma
->vm_end
- vma
->vm_start
;
5285 if (vma
->vm_pgoff
== 0) {
5286 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
5289 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5290 * mapped, all subsequent mappings should have the same size
5291 * and offset. Must be above the normal perf buffer.
5293 u64 aux_offset
, aux_size
;
5298 nr_pages
= vma_size
/ PAGE_SIZE
;
5300 mutex_lock(&event
->mmap_mutex
);
5307 aux_offset
= ACCESS_ONCE(rb
->user_page
->aux_offset
);
5308 aux_size
= ACCESS_ONCE(rb
->user_page
->aux_size
);
5310 if (aux_offset
< perf_data_size(rb
) + PAGE_SIZE
)
5313 if (aux_offset
!= vma
->vm_pgoff
<< PAGE_SHIFT
)
5316 /* already mapped with a different offset */
5317 if (rb_has_aux(rb
) && rb
->aux_pgoff
!= vma
->vm_pgoff
)
5320 if (aux_size
!= vma_size
|| aux_size
!= nr_pages
* PAGE_SIZE
)
5323 /* already mapped with a different size */
5324 if (rb_has_aux(rb
) && rb
->aux_nr_pages
!= nr_pages
)
5327 if (!is_power_of_2(nr_pages
))
5330 if (!atomic_inc_not_zero(&rb
->mmap_count
))
5333 if (rb_has_aux(rb
)) {
5334 atomic_inc(&rb
->aux_mmap_count
);
5339 atomic_set(&rb
->aux_mmap_count
, 1);
5340 user_extra
= nr_pages
;
5346 * If we have rb pages ensure they're a power-of-two number, so we
5347 * can do bitmasks instead of modulo.
5349 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
5352 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
5355 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
5357 mutex_lock(&event
->mmap_mutex
);
5359 if (event
->rb
->nr_pages
!= nr_pages
) {
5364 if (!atomic_inc_not_zero(&event
->rb
->mmap_count
)) {
5366 * Raced against perf_mmap_close() through
5367 * perf_event_set_output(). Try again, hope for better
5370 mutex_unlock(&event
->mmap_mutex
);
5377 user_extra
= nr_pages
+ 1;
5380 user_lock_limit
= sysctl_perf_event_mlock
>> (PAGE_SHIFT
- 10);
5383 * Increase the limit linearly with more CPUs:
5385 user_lock_limit
*= num_online_cpus();
5387 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
5389 if (user_locked
> user_lock_limit
)
5390 extra
= user_locked
- user_lock_limit
;
5392 lock_limit
= rlimit(RLIMIT_MEMLOCK
);
5393 lock_limit
>>= PAGE_SHIFT
;
5394 locked
= vma
->vm_mm
->pinned_vm
+ extra
;
5396 if ((locked
> lock_limit
) && perf_paranoid_tracepoint_raw() &&
5397 !capable(CAP_IPC_LOCK
)) {
5402 WARN_ON(!rb
&& event
->rb
);
5404 if (vma
->vm_flags
& VM_WRITE
)
5405 flags
|= RING_BUFFER_WRITABLE
;
5408 rb
= rb_alloc(nr_pages
,
5409 event
->attr
.watermark
? event
->attr
.wakeup_watermark
: 0,
5417 atomic_set(&rb
->mmap_count
, 1);
5418 rb
->mmap_user
= get_current_user();
5419 rb
->mmap_locked
= extra
;
5421 ring_buffer_attach(event
, rb
);
5423 perf_event_init_userpage(event
);
5424 perf_event_update_userpage(event
);
5426 ret
= rb_alloc_aux(rb
, event
, vma
->vm_pgoff
, nr_pages
,
5427 event
->attr
.aux_watermark
, flags
);
5429 rb
->aux_mmap_locked
= extra
;
5434 atomic_long_add(user_extra
, &user
->locked_vm
);
5435 vma
->vm_mm
->pinned_vm
+= extra
;
5437 atomic_inc(&event
->mmap_count
);
5439 atomic_dec(&rb
->mmap_count
);
5442 mutex_unlock(&event
->mmap_mutex
);
5445 * Since pinned accounting is per vm we cannot allow fork() to copy our
5448 vma
->vm_flags
|= VM_DONTCOPY
| VM_DONTEXPAND
| VM_DONTDUMP
;
5449 vma
->vm_ops
= &perf_mmap_vmops
;
5451 if (event
->pmu
->event_mapped
)
5452 event
->pmu
->event_mapped(event
, vma
->vm_mm
);
5457 static int perf_fasync(int fd
, struct file
*filp
, int on
)
5459 struct inode
*inode
= file_inode(filp
);
5460 struct perf_event
*event
= filp
->private_data
;
5464 retval
= fasync_helper(fd
, filp
, on
, &event
->fasync
);
5465 inode_unlock(inode
);
5473 static const struct file_operations perf_fops
= {
5474 .llseek
= no_llseek
,
5475 .release
= perf_release
,
5478 .unlocked_ioctl
= perf_ioctl
,
5479 .compat_ioctl
= perf_compat_ioctl
,
5481 .fasync
= perf_fasync
,
5487 * If there's data, ensure we set the poll() state and publish everything
5488 * to user-space before waking everybody up.
5491 static inline struct fasync_struct
**perf_event_fasync(struct perf_event
*event
)
5493 /* only the parent has fasync state */
5495 event
= event
->parent
;
5496 return &event
->fasync
;
5499 void perf_event_wakeup(struct perf_event
*event
)
5501 ring_buffer_wakeup(event
);
5503 if (event
->pending_kill
) {
5504 kill_fasync(perf_event_fasync(event
), SIGIO
, event
->pending_kill
);
5505 event
->pending_kill
= 0;
5509 static void perf_pending_event(struct irq_work
*entry
)
5511 struct perf_event
*event
= container_of(entry
,
5512 struct perf_event
, pending
);
5515 rctx
= perf_swevent_get_recursion_context();
5517 * If we 'fail' here, that's OK, it means recursion is already disabled
5518 * and we won't recurse 'further'.
5521 if (event
->pending_disable
) {
5522 event
->pending_disable
= 0;
5523 perf_event_disable_local(event
);
5526 if (event
->pending_wakeup
) {
5527 event
->pending_wakeup
= 0;
5528 perf_event_wakeup(event
);
5532 perf_swevent_put_recursion_context(rctx
);
5536 * We assume there is only KVM supporting the callbacks.
5537 * Later on, we might change it to a list if there is
5538 * another virtualization implementation supporting the callbacks.
5540 struct perf_guest_info_callbacks
*perf_guest_cbs
;
5542 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
5544 perf_guest_cbs
= cbs
;
5547 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks
);
5549 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
5551 perf_guest_cbs
= NULL
;
5554 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks
);
5557 perf_output_sample_regs(struct perf_output_handle
*handle
,
5558 struct pt_regs
*regs
, u64 mask
)
5561 DECLARE_BITMAP(_mask
, 64);
5563 bitmap_from_u64(_mask
, mask
);
5564 for_each_set_bit(bit
, _mask
, sizeof(mask
) * BITS_PER_BYTE
) {
5567 val
= perf_reg_value(regs
, bit
);
5568 perf_output_put(handle
, val
);
5572 static void perf_sample_regs_user(struct perf_regs
*regs_user
,
5573 struct pt_regs
*regs
,
5574 struct pt_regs
*regs_user_copy
)
5576 if (user_mode(regs
)) {
5577 regs_user
->abi
= perf_reg_abi(current
);
5578 regs_user
->regs
= regs
;
5579 } else if (current
->mm
) {
5580 perf_get_regs_user(regs_user
, regs
, regs_user_copy
);
5582 regs_user
->abi
= PERF_SAMPLE_REGS_ABI_NONE
;
5583 regs_user
->regs
= NULL
;
5587 static void perf_sample_regs_intr(struct perf_regs
*regs_intr
,
5588 struct pt_regs
*regs
)
5590 regs_intr
->regs
= regs
;
5591 regs_intr
->abi
= perf_reg_abi(current
);
5596 * Get remaining task size from user stack pointer.
5598 * It'd be better to take stack vma map and limit this more
5599 * precisly, but there's no way to get it safely under interrupt,
5600 * so using TASK_SIZE as limit.
5602 static u64
perf_ustack_task_size(struct pt_regs
*regs
)
5604 unsigned long addr
= perf_user_stack_pointer(regs
);
5606 if (!addr
|| addr
>= TASK_SIZE
)
5609 return TASK_SIZE
- addr
;
5613 perf_sample_ustack_size(u16 stack_size
, u16 header_size
,
5614 struct pt_regs
*regs
)
5618 /* No regs, no stack pointer, no dump. */
5623 * Check if we fit in with the requested stack size into the:
5625 * If we don't, we limit the size to the TASK_SIZE.
5627 * - remaining sample size
5628 * If we don't, we customize the stack size to
5629 * fit in to the remaining sample size.
5632 task_size
= min((u64
) USHRT_MAX
, perf_ustack_task_size(regs
));
5633 stack_size
= min(stack_size
, (u16
) task_size
);
5635 /* Current header size plus static size and dynamic size. */
5636 header_size
+= 2 * sizeof(u64
);
5638 /* Do we fit in with the current stack dump size? */
5639 if ((u16
) (header_size
+ stack_size
) < header_size
) {
5641 * If we overflow the maximum size for the sample,
5642 * we customize the stack dump size to fit in.
5644 stack_size
= USHRT_MAX
- header_size
- sizeof(u64
);
5645 stack_size
= round_up(stack_size
, sizeof(u64
));
5652 perf_output_sample_ustack(struct perf_output_handle
*handle
, u64 dump_size
,
5653 struct pt_regs
*regs
)
5655 /* Case of a kernel thread, nothing to dump */
5658 perf_output_put(handle
, size
);
5667 * - the size requested by user or the best one we can fit
5668 * in to the sample max size
5670 * - user stack dump data
5672 * - the actual dumped size
5676 perf_output_put(handle
, dump_size
);
5679 sp
= perf_user_stack_pointer(regs
);
5680 rem
= __output_copy_user(handle
, (void *) sp
, dump_size
);
5681 dyn_size
= dump_size
- rem
;
5683 perf_output_skip(handle
, rem
);
5686 perf_output_put(handle
, dyn_size
);
5690 static void __perf_event_header__init_id(struct perf_event_header
*header
,
5691 struct perf_sample_data
*data
,
5692 struct perf_event
*event
)
5694 u64 sample_type
= event
->attr
.sample_type
;
5696 data
->type
= sample_type
;
5697 header
->size
+= event
->id_header_size
;
5699 if (sample_type
& PERF_SAMPLE_TID
) {
5700 /* namespace issues */
5701 data
->tid_entry
.pid
= perf_event_pid(event
, current
);
5702 data
->tid_entry
.tid
= perf_event_tid(event
, current
);
5705 if (sample_type
& PERF_SAMPLE_TIME
)
5706 data
->time
= perf_event_clock(event
);
5708 if (sample_type
& (PERF_SAMPLE_ID
| PERF_SAMPLE_IDENTIFIER
))
5709 data
->id
= primary_event_id(event
);
5711 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
5712 data
->stream_id
= event
->id
;
5714 if (sample_type
& PERF_SAMPLE_CPU
) {
5715 data
->cpu_entry
.cpu
= raw_smp_processor_id();
5716 data
->cpu_entry
.reserved
= 0;
5720 void perf_event_header__init_id(struct perf_event_header
*header
,
5721 struct perf_sample_data
*data
,
5722 struct perf_event
*event
)
5724 if (event
->attr
.sample_id_all
)
5725 __perf_event_header__init_id(header
, data
, event
);
5728 static void __perf_event__output_id_sample(struct perf_output_handle
*handle
,
5729 struct perf_sample_data
*data
)
5731 u64 sample_type
= data
->type
;
5733 if (sample_type
& PERF_SAMPLE_TID
)
5734 perf_output_put(handle
, data
->tid_entry
);
5736 if (sample_type
& PERF_SAMPLE_TIME
)
5737 perf_output_put(handle
, data
->time
);
5739 if (sample_type
& PERF_SAMPLE_ID
)
5740 perf_output_put(handle
, data
->id
);
5742 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
5743 perf_output_put(handle
, data
->stream_id
);
5745 if (sample_type
& PERF_SAMPLE_CPU
)
5746 perf_output_put(handle
, data
->cpu_entry
);
5748 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
5749 perf_output_put(handle
, data
->id
);
5752 void perf_event__output_id_sample(struct perf_event
*event
,
5753 struct perf_output_handle
*handle
,
5754 struct perf_sample_data
*sample
)
5756 if (event
->attr
.sample_id_all
)
5757 __perf_event__output_id_sample(handle
, sample
);
5760 static void perf_output_read_one(struct perf_output_handle
*handle
,
5761 struct perf_event
*event
,
5762 u64 enabled
, u64 running
)
5764 u64 read_format
= event
->attr
.read_format
;
5768 values
[n
++] = perf_event_count(event
);
5769 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
5770 values
[n
++] = enabled
+
5771 atomic64_read(&event
->child_total_time_enabled
);
5773 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
5774 values
[n
++] = running
+
5775 atomic64_read(&event
->child_total_time_running
);
5777 if (read_format
& PERF_FORMAT_ID
)
5778 values
[n
++] = primary_event_id(event
);
5780 __output_copy(handle
, values
, n
* sizeof(u64
));
5783 static void perf_output_read_group(struct perf_output_handle
*handle
,
5784 struct perf_event
*event
,
5785 u64 enabled
, u64 running
)
5787 struct perf_event
*leader
= event
->group_leader
, *sub
;
5788 u64 read_format
= event
->attr
.read_format
;
5792 values
[n
++] = 1 + leader
->nr_siblings
;
5794 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
5795 values
[n
++] = enabled
;
5797 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
5798 values
[n
++] = running
;
5800 if (leader
!= event
)
5801 leader
->pmu
->read(leader
);
5803 values
[n
++] = perf_event_count(leader
);
5804 if (read_format
& PERF_FORMAT_ID
)
5805 values
[n
++] = primary_event_id(leader
);
5807 __output_copy(handle
, values
, n
* sizeof(u64
));
5809 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
5812 if ((sub
!= event
) &&
5813 (sub
->state
== PERF_EVENT_STATE_ACTIVE
))
5814 sub
->pmu
->read(sub
);
5816 values
[n
++] = perf_event_count(sub
);
5817 if (read_format
& PERF_FORMAT_ID
)
5818 values
[n
++] = primary_event_id(sub
);
5820 __output_copy(handle
, values
, n
* sizeof(u64
));
5824 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5825 PERF_FORMAT_TOTAL_TIME_RUNNING)
5828 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
5830 * The problem is that its both hard and excessively expensive to iterate the
5831 * child list, not to mention that its impossible to IPI the children running
5832 * on another CPU, from interrupt/NMI context.
5834 static void perf_output_read(struct perf_output_handle
*handle
,
5835 struct perf_event
*event
)
5837 u64 enabled
= 0, running
= 0, now
;
5838 u64 read_format
= event
->attr
.read_format
;
5841 * compute total_time_enabled, total_time_running
5842 * based on snapshot values taken when the event
5843 * was last scheduled in.
5845 * we cannot simply called update_context_time()
5846 * because of locking issue as we are called in
5849 if (read_format
& PERF_FORMAT_TOTAL_TIMES
)
5850 calc_timer_values(event
, &now
, &enabled
, &running
);
5852 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
)
5853 perf_output_read_group(handle
, event
, enabled
, running
);
5855 perf_output_read_one(handle
, event
, enabled
, running
);
5858 void perf_output_sample(struct perf_output_handle
*handle
,
5859 struct perf_event_header
*header
,
5860 struct perf_sample_data
*data
,
5861 struct perf_event
*event
)
5863 u64 sample_type
= data
->type
;
5865 perf_output_put(handle
, *header
);
5867 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
5868 perf_output_put(handle
, data
->id
);
5870 if (sample_type
& PERF_SAMPLE_IP
)
5871 perf_output_put(handle
, data
->ip
);
5873 if (sample_type
& PERF_SAMPLE_TID
)
5874 perf_output_put(handle
, data
->tid_entry
);
5876 if (sample_type
& PERF_SAMPLE_TIME
)
5877 perf_output_put(handle
, data
->time
);
5879 if (sample_type
& PERF_SAMPLE_ADDR
)
5880 perf_output_put(handle
, data
->addr
);
5882 if (sample_type
& PERF_SAMPLE_ID
)
5883 perf_output_put(handle
, data
->id
);
5885 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
5886 perf_output_put(handle
, data
->stream_id
);
5888 if (sample_type
& PERF_SAMPLE_CPU
)
5889 perf_output_put(handle
, data
->cpu_entry
);
5891 if (sample_type
& PERF_SAMPLE_PERIOD
)
5892 perf_output_put(handle
, data
->period
);
5894 if (sample_type
& PERF_SAMPLE_READ
)
5895 perf_output_read(handle
, event
);
5897 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
5898 if (data
->callchain
) {
5901 if (data
->callchain
)
5902 size
+= data
->callchain
->nr
;
5904 size
*= sizeof(u64
);
5906 __output_copy(handle
, data
->callchain
, size
);
5909 perf_output_put(handle
, nr
);
5913 if (sample_type
& PERF_SAMPLE_RAW
) {
5914 struct perf_raw_record
*raw
= data
->raw
;
5917 struct perf_raw_frag
*frag
= &raw
->frag
;
5919 perf_output_put(handle
, raw
->size
);
5922 __output_custom(handle
, frag
->copy
,
5923 frag
->data
, frag
->size
);
5925 __output_copy(handle
, frag
->data
,
5928 if (perf_raw_frag_last(frag
))
5933 __output_skip(handle
, NULL
, frag
->pad
);
5939 .size
= sizeof(u32
),
5942 perf_output_put(handle
, raw
);
5946 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
5947 if (data
->br_stack
) {
5950 size
= data
->br_stack
->nr
5951 * sizeof(struct perf_branch_entry
);
5953 perf_output_put(handle
, data
->br_stack
->nr
);
5954 perf_output_copy(handle
, data
->br_stack
->entries
, size
);
5957 * we always store at least the value of nr
5960 perf_output_put(handle
, nr
);
5964 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
5965 u64 abi
= data
->regs_user
.abi
;
5968 * If there are no regs to dump, notice it through
5969 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5971 perf_output_put(handle
, abi
);
5974 u64 mask
= event
->attr
.sample_regs_user
;
5975 perf_output_sample_regs(handle
,
5976 data
->regs_user
.regs
,
5981 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
5982 perf_output_sample_ustack(handle
,
5983 data
->stack_user_size
,
5984 data
->regs_user
.regs
);
5987 if (sample_type
& PERF_SAMPLE_WEIGHT
)
5988 perf_output_put(handle
, data
->weight
);
5990 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
5991 perf_output_put(handle
, data
->data_src
.val
);
5993 if (sample_type
& PERF_SAMPLE_TRANSACTION
)
5994 perf_output_put(handle
, data
->txn
);
5996 if (sample_type
& PERF_SAMPLE_REGS_INTR
) {
5997 u64 abi
= data
->regs_intr
.abi
;
5999 * If there are no regs to dump, notice it through
6000 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6002 perf_output_put(handle
, abi
);
6005 u64 mask
= event
->attr
.sample_regs_intr
;
6007 perf_output_sample_regs(handle
,
6008 data
->regs_intr
.regs
,
6013 if (sample_type
& PERF_SAMPLE_PHYS_ADDR
)
6014 perf_output_put(handle
, data
->phys_addr
);
6016 if (!event
->attr
.watermark
) {
6017 int wakeup_events
= event
->attr
.wakeup_events
;
6019 if (wakeup_events
) {
6020 struct ring_buffer
*rb
= handle
->rb
;
6021 int events
= local_inc_return(&rb
->events
);
6023 if (events
>= wakeup_events
) {
6024 local_sub(wakeup_events
, &rb
->events
);
6025 local_inc(&rb
->wakeup
);
6031 static u64
perf_virt_to_phys(u64 virt
)
6034 struct page
*p
= NULL
;
6039 if (virt
>= TASK_SIZE
) {
6040 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6041 if (virt_addr_valid((void *)(uintptr_t)virt
) &&
6042 !(virt
>= VMALLOC_START
&& virt
< VMALLOC_END
))
6043 phys_addr
= (u64
)virt_to_phys((void *)(uintptr_t)virt
);
6046 * Walking the pages tables for user address.
6047 * Interrupts are disabled, so it prevents any tear down
6048 * of the page tables.
6049 * Try IRQ-safe __get_user_pages_fast first.
6050 * If failed, leave phys_addr as 0.
6052 if ((current
->mm
!= NULL
) &&
6053 (__get_user_pages_fast(virt
, 1, 0, &p
) == 1))
6054 phys_addr
= page_to_phys(p
) + virt
% PAGE_SIZE
;
6063 void perf_prepare_sample(struct perf_event_header
*header
,
6064 struct perf_sample_data
*data
,
6065 struct perf_event
*event
,
6066 struct pt_regs
*regs
)
6068 u64 sample_type
= event
->attr
.sample_type
;
6070 header
->type
= PERF_RECORD_SAMPLE
;
6071 header
->size
= sizeof(*header
) + event
->header_size
;
6074 header
->misc
|= perf_misc_flags(regs
);
6076 __perf_event_header__init_id(header
, data
, event
);
6078 if (sample_type
& PERF_SAMPLE_IP
)
6079 data
->ip
= perf_instruction_pointer(regs
);
6081 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
6084 data
->callchain
= perf_callchain(event
, regs
);
6086 if (data
->callchain
)
6087 size
+= data
->callchain
->nr
;
6089 header
->size
+= size
* sizeof(u64
);
6092 if (sample_type
& PERF_SAMPLE_RAW
) {
6093 struct perf_raw_record
*raw
= data
->raw
;
6097 struct perf_raw_frag
*frag
= &raw
->frag
;
6102 if (perf_raw_frag_last(frag
))
6107 size
= round_up(sum
+ sizeof(u32
), sizeof(u64
));
6108 raw
->size
= size
- sizeof(u32
);
6109 frag
->pad
= raw
->size
- sum
;
6114 header
->size
+= size
;
6117 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
6118 int size
= sizeof(u64
); /* nr */
6119 if (data
->br_stack
) {
6120 size
+= data
->br_stack
->nr
6121 * sizeof(struct perf_branch_entry
);
6123 header
->size
+= size
;
6126 if (sample_type
& (PERF_SAMPLE_REGS_USER
| PERF_SAMPLE_STACK_USER
))
6127 perf_sample_regs_user(&data
->regs_user
, regs
,
6128 &data
->regs_user_copy
);
6130 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
6131 /* regs dump ABI info */
6132 int size
= sizeof(u64
);
6134 if (data
->regs_user
.regs
) {
6135 u64 mask
= event
->attr
.sample_regs_user
;
6136 size
+= hweight64(mask
) * sizeof(u64
);
6139 header
->size
+= size
;
6142 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
6144 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6145 * processed as the last one or have additional check added
6146 * in case new sample type is added, because we could eat
6147 * up the rest of the sample size.
6149 u16 stack_size
= event
->attr
.sample_stack_user
;
6150 u16 size
= sizeof(u64
);
6152 stack_size
= perf_sample_ustack_size(stack_size
, header
->size
,
6153 data
->regs_user
.regs
);
6156 * If there is something to dump, add space for the dump
6157 * itself and for the field that tells the dynamic size,
6158 * which is how many have been actually dumped.
6161 size
+= sizeof(u64
) + stack_size
;
6163 data
->stack_user_size
= stack_size
;
6164 header
->size
+= size
;
6167 if (sample_type
& PERF_SAMPLE_REGS_INTR
) {
6168 /* regs dump ABI info */
6169 int size
= sizeof(u64
);
6171 perf_sample_regs_intr(&data
->regs_intr
, regs
);
6173 if (data
->regs_intr
.regs
) {
6174 u64 mask
= event
->attr
.sample_regs_intr
;
6176 size
+= hweight64(mask
) * sizeof(u64
);
6179 header
->size
+= size
;
6182 if (sample_type
& PERF_SAMPLE_PHYS_ADDR
)
6183 data
->phys_addr
= perf_virt_to_phys(data
->addr
);
6186 static void __always_inline
6187 __perf_event_output(struct perf_event
*event
,
6188 struct perf_sample_data
*data
,
6189 struct pt_regs
*regs
,
6190 int (*output_begin
)(struct perf_output_handle
*,
6191 struct perf_event
*,
6194 struct perf_output_handle handle
;
6195 struct perf_event_header header
;
6197 /* protect the callchain buffers */
6200 perf_prepare_sample(&header
, data
, event
, regs
);
6202 if (output_begin(&handle
, event
, header
.size
))
6205 perf_output_sample(&handle
, &header
, data
, event
);
6207 perf_output_end(&handle
);
6214 perf_event_output_forward(struct perf_event
*event
,
6215 struct perf_sample_data
*data
,
6216 struct pt_regs
*regs
)
6218 __perf_event_output(event
, data
, regs
, perf_output_begin_forward
);
6222 perf_event_output_backward(struct perf_event
*event
,
6223 struct perf_sample_data
*data
,
6224 struct pt_regs
*regs
)
6226 __perf_event_output(event
, data
, regs
, perf_output_begin_backward
);
6230 perf_event_output(struct perf_event
*event
,
6231 struct perf_sample_data
*data
,
6232 struct pt_regs
*regs
)
6234 __perf_event_output(event
, data
, regs
, perf_output_begin
);
6241 struct perf_read_event
{
6242 struct perf_event_header header
;
6249 perf_event_read_event(struct perf_event
*event
,
6250 struct task_struct
*task
)
6252 struct perf_output_handle handle
;
6253 struct perf_sample_data sample
;
6254 struct perf_read_event read_event
= {
6256 .type
= PERF_RECORD_READ
,
6258 .size
= sizeof(read_event
) + event
->read_size
,
6260 .pid
= perf_event_pid(event
, task
),
6261 .tid
= perf_event_tid(event
, task
),
6265 perf_event_header__init_id(&read_event
.header
, &sample
, event
);
6266 ret
= perf_output_begin(&handle
, event
, read_event
.header
.size
);
6270 perf_output_put(&handle
, read_event
);
6271 perf_output_read(&handle
, event
);
6272 perf_event__output_id_sample(event
, &handle
, &sample
);
6274 perf_output_end(&handle
);
6277 typedef void (perf_iterate_f
)(struct perf_event
*event
, void *data
);
6280 perf_iterate_ctx(struct perf_event_context
*ctx
,
6281 perf_iterate_f output
,
6282 void *data
, bool all
)
6284 struct perf_event
*event
;
6286 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
6288 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
6290 if (!event_filter_match(event
))
6294 output(event
, data
);
6298 static void perf_iterate_sb_cpu(perf_iterate_f output
, void *data
)
6300 struct pmu_event_list
*pel
= this_cpu_ptr(&pmu_sb_events
);
6301 struct perf_event
*event
;
6303 list_for_each_entry_rcu(event
, &pel
->list
, sb_list
) {
6305 * Skip events that are not fully formed yet; ensure that
6306 * if we observe event->ctx, both event and ctx will be
6307 * complete enough. See perf_install_in_context().
6309 if (!smp_load_acquire(&event
->ctx
))
6312 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
6314 if (!event_filter_match(event
))
6316 output(event
, data
);
6321 * Iterate all events that need to receive side-band events.
6323 * For new callers; ensure that account_pmu_sb_event() includes
6324 * your event, otherwise it might not get delivered.
6327 perf_iterate_sb(perf_iterate_f output
, void *data
,
6328 struct perf_event_context
*task_ctx
)
6330 struct perf_event_context
*ctx
;
6337 * If we have task_ctx != NULL we only notify the task context itself.
6338 * The task_ctx is set only for EXIT events before releasing task
6342 perf_iterate_ctx(task_ctx
, output
, data
, false);
6346 perf_iterate_sb_cpu(output
, data
);
6348 for_each_task_context_nr(ctxn
) {
6349 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
6351 perf_iterate_ctx(ctx
, output
, data
, false);
6359 * Clear all file-based filters at exec, they'll have to be
6360 * re-instated when/if these objects are mmapped again.
6362 static void perf_event_addr_filters_exec(struct perf_event
*event
, void *data
)
6364 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
6365 struct perf_addr_filter
*filter
;
6366 unsigned int restart
= 0, count
= 0;
6367 unsigned long flags
;
6369 if (!has_addr_filter(event
))
6372 raw_spin_lock_irqsave(&ifh
->lock
, flags
);
6373 list_for_each_entry(filter
, &ifh
->list
, entry
) {
6374 if (filter
->inode
) {
6375 event
->addr_filters_offs
[count
] = 0;
6383 event
->addr_filters_gen
++;
6384 raw_spin_unlock_irqrestore(&ifh
->lock
, flags
);
6387 perf_event_stop(event
, 1);
6390 void perf_event_exec(void)
6392 struct perf_event_context
*ctx
;
6396 for_each_task_context_nr(ctxn
) {
6397 ctx
= current
->perf_event_ctxp
[ctxn
];
6401 perf_event_enable_on_exec(ctxn
);
6403 perf_iterate_ctx(ctx
, perf_event_addr_filters_exec
, NULL
,
6409 struct remote_output
{
6410 struct ring_buffer
*rb
;
6414 static void __perf_event_output_stop(struct perf_event
*event
, void *data
)
6416 struct perf_event
*parent
= event
->parent
;
6417 struct remote_output
*ro
= data
;
6418 struct ring_buffer
*rb
= ro
->rb
;
6419 struct stop_event_data sd
= {
6423 if (!has_aux(event
))
6430 * In case of inheritance, it will be the parent that links to the
6431 * ring-buffer, but it will be the child that's actually using it.
6433 * We are using event::rb to determine if the event should be stopped,
6434 * however this may race with ring_buffer_attach() (through set_output),
6435 * which will make us skip the event that actually needs to be stopped.
6436 * So ring_buffer_attach() has to stop an aux event before re-assigning
6439 if (rcu_dereference(parent
->rb
) == rb
)
6440 ro
->err
= __perf_event_stop(&sd
);
6443 static int __perf_pmu_output_stop(void *info
)
6445 struct perf_event
*event
= info
;
6446 struct pmu
*pmu
= event
->pmu
;
6447 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
6448 struct remote_output ro
= {
6453 perf_iterate_ctx(&cpuctx
->ctx
, __perf_event_output_stop
, &ro
, false);
6454 if (cpuctx
->task_ctx
)
6455 perf_iterate_ctx(cpuctx
->task_ctx
, __perf_event_output_stop
,
6462 static void perf_pmu_output_stop(struct perf_event
*event
)
6464 struct perf_event
*iter
;
6469 list_for_each_entry_rcu(iter
, &event
->rb
->event_list
, rb_entry
) {
6471 * For per-CPU events, we need to make sure that neither they
6472 * nor their children are running; for cpu==-1 events it's
6473 * sufficient to stop the event itself if it's active, since
6474 * it can't have children.
6478 cpu
= READ_ONCE(iter
->oncpu
);
6483 err
= cpu_function_call(cpu
, __perf_pmu_output_stop
, event
);
6484 if (err
== -EAGAIN
) {
6493 * task tracking -- fork/exit
6495 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6498 struct perf_task_event
{
6499 struct task_struct
*task
;
6500 struct perf_event_context
*task_ctx
;
6503 struct perf_event_header header
;
6513 static int perf_event_task_match(struct perf_event
*event
)
6515 return event
->attr
.comm
|| event
->attr
.mmap
||
6516 event
->attr
.mmap2
|| event
->attr
.mmap_data
||
6520 static void perf_event_task_output(struct perf_event
*event
,
6523 struct perf_task_event
*task_event
= data
;
6524 struct perf_output_handle handle
;
6525 struct perf_sample_data sample
;
6526 struct task_struct
*task
= task_event
->task
;
6527 int ret
, size
= task_event
->event_id
.header
.size
;
6529 if (!perf_event_task_match(event
))
6532 perf_event_header__init_id(&task_event
->event_id
.header
, &sample
, event
);
6534 ret
= perf_output_begin(&handle
, event
,
6535 task_event
->event_id
.header
.size
);
6539 task_event
->event_id
.pid
= perf_event_pid(event
, task
);
6540 task_event
->event_id
.ppid
= perf_event_pid(event
, current
);
6542 task_event
->event_id
.tid
= perf_event_tid(event
, task
);
6543 task_event
->event_id
.ptid
= perf_event_tid(event
, current
);
6545 task_event
->event_id
.time
= perf_event_clock(event
);
6547 perf_output_put(&handle
, task_event
->event_id
);
6549 perf_event__output_id_sample(event
, &handle
, &sample
);
6551 perf_output_end(&handle
);
6553 task_event
->event_id
.header
.size
= size
;
6556 static void perf_event_task(struct task_struct
*task
,
6557 struct perf_event_context
*task_ctx
,
6560 struct perf_task_event task_event
;
6562 if (!atomic_read(&nr_comm_events
) &&
6563 !atomic_read(&nr_mmap_events
) &&
6564 !atomic_read(&nr_task_events
))
6567 task_event
= (struct perf_task_event
){
6569 .task_ctx
= task_ctx
,
6572 .type
= new ? PERF_RECORD_FORK
: PERF_RECORD_EXIT
,
6574 .size
= sizeof(task_event
.event_id
),
6584 perf_iterate_sb(perf_event_task_output
,
6589 void perf_event_fork(struct task_struct
*task
)
6591 perf_event_task(task
, NULL
, 1);
6592 perf_event_namespaces(task
);
6599 struct perf_comm_event
{
6600 struct task_struct
*task
;
6605 struct perf_event_header header
;
6612 static int perf_event_comm_match(struct perf_event
*event
)
6614 return event
->attr
.comm
;
6617 static void perf_event_comm_output(struct perf_event
*event
,
6620 struct perf_comm_event
*comm_event
= data
;
6621 struct perf_output_handle handle
;
6622 struct perf_sample_data sample
;
6623 int size
= comm_event
->event_id
.header
.size
;
6626 if (!perf_event_comm_match(event
))
6629 perf_event_header__init_id(&comm_event
->event_id
.header
, &sample
, event
);
6630 ret
= perf_output_begin(&handle
, event
,
6631 comm_event
->event_id
.header
.size
);
6636 comm_event
->event_id
.pid
= perf_event_pid(event
, comm_event
->task
);
6637 comm_event
->event_id
.tid
= perf_event_tid(event
, comm_event
->task
);
6639 perf_output_put(&handle
, comm_event
->event_id
);
6640 __output_copy(&handle
, comm_event
->comm
,
6641 comm_event
->comm_size
);
6643 perf_event__output_id_sample(event
, &handle
, &sample
);
6645 perf_output_end(&handle
);
6647 comm_event
->event_id
.header
.size
= size
;
6650 static void perf_event_comm_event(struct perf_comm_event
*comm_event
)
6652 char comm
[TASK_COMM_LEN
];
6655 memset(comm
, 0, sizeof(comm
));
6656 strlcpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
6657 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
6659 comm_event
->comm
= comm
;
6660 comm_event
->comm_size
= size
;
6662 comm_event
->event_id
.header
.size
= sizeof(comm_event
->event_id
) + size
;
6664 perf_iterate_sb(perf_event_comm_output
,
6669 void perf_event_comm(struct task_struct
*task
, bool exec
)
6671 struct perf_comm_event comm_event
;
6673 if (!atomic_read(&nr_comm_events
))
6676 comm_event
= (struct perf_comm_event
){
6682 .type
= PERF_RECORD_COMM
,
6683 .misc
= exec
? PERF_RECORD_MISC_COMM_EXEC
: 0,
6691 perf_event_comm_event(&comm_event
);
6695 * namespaces tracking
6698 struct perf_namespaces_event
{
6699 struct task_struct
*task
;
6702 struct perf_event_header header
;
6707 struct perf_ns_link_info link_info
[NR_NAMESPACES
];
6711 static int perf_event_namespaces_match(struct perf_event
*event
)
6713 return event
->attr
.namespaces
;
6716 static void perf_event_namespaces_output(struct perf_event
*event
,
6719 struct perf_namespaces_event
*namespaces_event
= data
;
6720 struct perf_output_handle handle
;
6721 struct perf_sample_data sample
;
6724 if (!perf_event_namespaces_match(event
))
6727 perf_event_header__init_id(&namespaces_event
->event_id
.header
,
6729 ret
= perf_output_begin(&handle
, event
,
6730 namespaces_event
->event_id
.header
.size
);
6734 namespaces_event
->event_id
.pid
= perf_event_pid(event
,
6735 namespaces_event
->task
);
6736 namespaces_event
->event_id
.tid
= perf_event_tid(event
,
6737 namespaces_event
->task
);
6739 perf_output_put(&handle
, namespaces_event
->event_id
);
6741 perf_event__output_id_sample(event
, &handle
, &sample
);
6743 perf_output_end(&handle
);
6746 static void perf_fill_ns_link_info(struct perf_ns_link_info
*ns_link_info
,
6747 struct task_struct
*task
,
6748 const struct proc_ns_operations
*ns_ops
)
6750 struct path ns_path
;
6751 struct inode
*ns_inode
;
6754 error
= ns_get_path(&ns_path
, task
, ns_ops
);
6756 ns_inode
= ns_path
.dentry
->d_inode
;
6757 ns_link_info
->dev
= new_encode_dev(ns_inode
->i_sb
->s_dev
);
6758 ns_link_info
->ino
= ns_inode
->i_ino
;
6762 void perf_event_namespaces(struct task_struct
*task
)
6764 struct perf_namespaces_event namespaces_event
;
6765 struct perf_ns_link_info
*ns_link_info
;
6767 if (!atomic_read(&nr_namespaces_events
))
6770 namespaces_event
= (struct perf_namespaces_event
){
6774 .type
= PERF_RECORD_NAMESPACES
,
6776 .size
= sizeof(namespaces_event
.event_id
),
6780 .nr_namespaces
= NR_NAMESPACES
,
6781 /* .link_info[NR_NAMESPACES] */
6785 ns_link_info
= namespaces_event
.event_id
.link_info
;
6787 perf_fill_ns_link_info(&ns_link_info
[MNT_NS_INDEX
],
6788 task
, &mntns_operations
);
6790 #ifdef CONFIG_USER_NS
6791 perf_fill_ns_link_info(&ns_link_info
[USER_NS_INDEX
],
6792 task
, &userns_operations
);
6794 #ifdef CONFIG_NET_NS
6795 perf_fill_ns_link_info(&ns_link_info
[NET_NS_INDEX
],
6796 task
, &netns_operations
);
6798 #ifdef CONFIG_UTS_NS
6799 perf_fill_ns_link_info(&ns_link_info
[UTS_NS_INDEX
],
6800 task
, &utsns_operations
);
6802 #ifdef CONFIG_IPC_NS
6803 perf_fill_ns_link_info(&ns_link_info
[IPC_NS_INDEX
],
6804 task
, &ipcns_operations
);
6806 #ifdef CONFIG_PID_NS
6807 perf_fill_ns_link_info(&ns_link_info
[PID_NS_INDEX
],
6808 task
, &pidns_operations
);
6810 #ifdef CONFIG_CGROUPS
6811 perf_fill_ns_link_info(&ns_link_info
[CGROUP_NS_INDEX
],
6812 task
, &cgroupns_operations
);
6815 perf_iterate_sb(perf_event_namespaces_output
,
6824 struct perf_mmap_event
{
6825 struct vm_area_struct
*vma
;
6827 const char *file_name
;
6835 struct perf_event_header header
;
6845 static int perf_event_mmap_match(struct perf_event
*event
,
6848 struct perf_mmap_event
*mmap_event
= data
;
6849 struct vm_area_struct
*vma
= mmap_event
->vma
;
6850 int executable
= vma
->vm_flags
& VM_EXEC
;
6852 return (!executable
&& event
->attr
.mmap_data
) ||
6853 (executable
&& (event
->attr
.mmap
|| event
->attr
.mmap2
));
6856 static void perf_event_mmap_output(struct perf_event
*event
,
6859 struct perf_mmap_event
*mmap_event
= data
;
6860 struct perf_output_handle handle
;
6861 struct perf_sample_data sample
;
6862 int size
= mmap_event
->event_id
.header
.size
;
6865 if (!perf_event_mmap_match(event
, data
))
6868 if (event
->attr
.mmap2
) {
6869 mmap_event
->event_id
.header
.type
= PERF_RECORD_MMAP2
;
6870 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->maj
);
6871 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->min
);
6872 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->ino
);
6873 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->ino_generation
);
6874 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->prot
);
6875 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->flags
);
6878 perf_event_header__init_id(&mmap_event
->event_id
.header
, &sample
, event
);
6879 ret
= perf_output_begin(&handle
, event
,
6880 mmap_event
->event_id
.header
.size
);
6884 mmap_event
->event_id
.pid
= perf_event_pid(event
, current
);
6885 mmap_event
->event_id
.tid
= perf_event_tid(event
, current
);
6887 perf_output_put(&handle
, mmap_event
->event_id
);
6889 if (event
->attr
.mmap2
) {
6890 perf_output_put(&handle
, mmap_event
->maj
);
6891 perf_output_put(&handle
, mmap_event
->min
);
6892 perf_output_put(&handle
, mmap_event
->ino
);
6893 perf_output_put(&handle
, mmap_event
->ino_generation
);
6894 perf_output_put(&handle
, mmap_event
->prot
);
6895 perf_output_put(&handle
, mmap_event
->flags
);
6898 __output_copy(&handle
, mmap_event
->file_name
,
6899 mmap_event
->file_size
);
6901 perf_event__output_id_sample(event
, &handle
, &sample
);
6903 perf_output_end(&handle
);
6905 mmap_event
->event_id
.header
.size
= size
;
6908 static void perf_event_mmap_event(struct perf_mmap_event
*mmap_event
)
6910 struct vm_area_struct
*vma
= mmap_event
->vma
;
6911 struct file
*file
= vma
->vm_file
;
6912 int maj
= 0, min
= 0;
6913 u64 ino
= 0, gen
= 0;
6914 u32 prot
= 0, flags
= 0;
6920 if (vma
->vm_flags
& VM_READ
)
6922 if (vma
->vm_flags
& VM_WRITE
)
6924 if (vma
->vm_flags
& VM_EXEC
)
6927 if (vma
->vm_flags
& VM_MAYSHARE
)
6930 flags
= MAP_PRIVATE
;
6932 if (vma
->vm_flags
& VM_DENYWRITE
)
6933 flags
|= MAP_DENYWRITE
;
6934 if (vma
->vm_flags
& VM_MAYEXEC
)
6935 flags
|= MAP_EXECUTABLE
;
6936 if (vma
->vm_flags
& VM_LOCKED
)
6937 flags
|= MAP_LOCKED
;
6938 if (vma
->vm_flags
& VM_HUGETLB
)
6939 flags
|= MAP_HUGETLB
;
6942 struct inode
*inode
;
6945 buf
= kmalloc(PATH_MAX
, GFP_KERNEL
);
6951 * d_path() works from the end of the rb backwards, so we
6952 * need to add enough zero bytes after the string to handle
6953 * the 64bit alignment we do later.
6955 name
= file_path(file
, buf
, PATH_MAX
- sizeof(u64
));
6960 inode
= file_inode(vma
->vm_file
);
6961 dev
= inode
->i_sb
->s_dev
;
6963 gen
= inode
->i_generation
;
6969 if (vma
->vm_ops
&& vma
->vm_ops
->name
) {
6970 name
= (char *) vma
->vm_ops
->name(vma
);
6975 name
= (char *)arch_vma_name(vma
);
6979 if (vma
->vm_start
<= vma
->vm_mm
->start_brk
&&
6980 vma
->vm_end
>= vma
->vm_mm
->brk
) {
6984 if (vma
->vm_start
<= vma
->vm_mm
->start_stack
&&
6985 vma
->vm_end
>= vma
->vm_mm
->start_stack
) {
6995 strlcpy(tmp
, name
, sizeof(tmp
));
6999 * Since our buffer works in 8 byte units we need to align our string
7000 * size to a multiple of 8. However, we must guarantee the tail end is
7001 * zero'd out to avoid leaking random bits to userspace.
7003 size
= strlen(name
)+1;
7004 while (!IS_ALIGNED(size
, sizeof(u64
)))
7005 name
[size
++] = '\0';
7007 mmap_event
->file_name
= name
;
7008 mmap_event
->file_size
= size
;
7009 mmap_event
->maj
= maj
;
7010 mmap_event
->min
= min
;
7011 mmap_event
->ino
= ino
;
7012 mmap_event
->ino_generation
= gen
;
7013 mmap_event
->prot
= prot
;
7014 mmap_event
->flags
= flags
;
7016 if (!(vma
->vm_flags
& VM_EXEC
))
7017 mmap_event
->event_id
.header
.misc
|= PERF_RECORD_MISC_MMAP_DATA
;
7019 mmap_event
->event_id
.header
.size
= sizeof(mmap_event
->event_id
) + size
;
7021 perf_iterate_sb(perf_event_mmap_output
,
7029 * Check whether inode and address range match filter criteria.
7031 static bool perf_addr_filter_match(struct perf_addr_filter
*filter
,
7032 struct file
*file
, unsigned long offset
,
7035 if (filter
->inode
!= file_inode(file
))
7038 if (filter
->offset
> offset
+ size
)
7041 if (filter
->offset
+ filter
->size
< offset
)
7047 static void __perf_addr_filters_adjust(struct perf_event
*event
, void *data
)
7049 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
7050 struct vm_area_struct
*vma
= data
;
7051 unsigned long off
= vma
->vm_pgoff
<< PAGE_SHIFT
, flags
;
7052 struct file
*file
= vma
->vm_file
;
7053 struct perf_addr_filter
*filter
;
7054 unsigned int restart
= 0, count
= 0;
7056 if (!has_addr_filter(event
))
7062 raw_spin_lock_irqsave(&ifh
->lock
, flags
);
7063 list_for_each_entry(filter
, &ifh
->list
, entry
) {
7064 if (perf_addr_filter_match(filter
, file
, off
,
7065 vma
->vm_end
- vma
->vm_start
)) {
7066 event
->addr_filters_offs
[count
] = vma
->vm_start
;
7074 event
->addr_filters_gen
++;
7075 raw_spin_unlock_irqrestore(&ifh
->lock
, flags
);
7078 perf_event_stop(event
, 1);
7082 * Adjust all task's events' filters to the new vma
7084 static void perf_addr_filters_adjust(struct vm_area_struct
*vma
)
7086 struct perf_event_context
*ctx
;
7090 * Data tracing isn't supported yet and as such there is no need
7091 * to keep track of anything that isn't related to executable code:
7093 if (!(vma
->vm_flags
& VM_EXEC
))
7097 for_each_task_context_nr(ctxn
) {
7098 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
7102 perf_iterate_ctx(ctx
, __perf_addr_filters_adjust
, vma
, true);
7107 void perf_event_mmap(struct vm_area_struct
*vma
)
7109 struct perf_mmap_event mmap_event
;
7111 if (!atomic_read(&nr_mmap_events
))
7114 mmap_event
= (struct perf_mmap_event
){
7120 .type
= PERF_RECORD_MMAP
,
7121 .misc
= PERF_RECORD_MISC_USER
,
7126 .start
= vma
->vm_start
,
7127 .len
= vma
->vm_end
- vma
->vm_start
,
7128 .pgoff
= (u64
)vma
->vm_pgoff
<< PAGE_SHIFT
,
7130 /* .maj (attr_mmap2 only) */
7131 /* .min (attr_mmap2 only) */
7132 /* .ino (attr_mmap2 only) */
7133 /* .ino_generation (attr_mmap2 only) */
7134 /* .prot (attr_mmap2 only) */
7135 /* .flags (attr_mmap2 only) */
7138 perf_addr_filters_adjust(vma
);
7139 perf_event_mmap_event(&mmap_event
);
7142 void perf_event_aux_event(struct perf_event
*event
, unsigned long head
,
7143 unsigned long size
, u64 flags
)
7145 struct perf_output_handle handle
;
7146 struct perf_sample_data sample
;
7147 struct perf_aux_event
{
7148 struct perf_event_header header
;
7154 .type
= PERF_RECORD_AUX
,
7156 .size
= sizeof(rec
),
7164 perf_event_header__init_id(&rec
.header
, &sample
, event
);
7165 ret
= perf_output_begin(&handle
, event
, rec
.header
.size
);
7170 perf_output_put(&handle
, rec
);
7171 perf_event__output_id_sample(event
, &handle
, &sample
);
7173 perf_output_end(&handle
);
7177 * Lost/dropped samples logging
7179 void perf_log_lost_samples(struct perf_event
*event
, u64 lost
)
7181 struct perf_output_handle handle
;
7182 struct perf_sample_data sample
;
7186 struct perf_event_header header
;
7188 } lost_samples_event
= {
7190 .type
= PERF_RECORD_LOST_SAMPLES
,
7192 .size
= sizeof(lost_samples_event
),
7197 perf_event_header__init_id(&lost_samples_event
.header
, &sample
, event
);
7199 ret
= perf_output_begin(&handle
, event
,
7200 lost_samples_event
.header
.size
);
7204 perf_output_put(&handle
, lost_samples_event
);
7205 perf_event__output_id_sample(event
, &handle
, &sample
);
7206 perf_output_end(&handle
);
7210 * context_switch tracking
7213 struct perf_switch_event
{
7214 struct task_struct
*task
;
7215 struct task_struct
*next_prev
;
7218 struct perf_event_header header
;
7224 static int perf_event_switch_match(struct perf_event
*event
)
7226 return event
->attr
.context_switch
;
7229 static void perf_event_switch_output(struct perf_event
*event
, void *data
)
7231 struct perf_switch_event
*se
= data
;
7232 struct perf_output_handle handle
;
7233 struct perf_sample_data sample
;
7236 if (!perf_event_switch_match(event
))
7239 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7240 if (event
->ctx
->task
) {
7241 se
->event_id
.header
.type
= PERF_RECORD_SWITCH
;
7242 se
->event_id
.header
.size
= sizeof(se
->event_id
.header
);
7244 se
->event_id
.header
.type
= PERF_RECORD_SWITCH_CPU_WIDE
;
7245 se
->event_id
.header
.size
= sizeof(se
->event_id
);
7246 se
->event_id
.next_prev_pid
=
7247 perf_event_pid(event
, se
->next_prev
);
7248 se
->event_id
.next_prev_tid
=
7249 perf_event_tid(event
, se
->next_prev
);
7252 perf_event_header__init_id(&se
->event_id
.header
, &sample
, event
);
7254 ret
= perf_output_begin(&handle
, event
, se
->event_id
.header
.size
);
7258 if (event
->ctx
->task
)
7259 perf_output_put(&handle
, se
->event_id
.header
);
7261 perf_output_put(&handle
, se
->event_id
);
7263 perf_event__output_id_sample(event
, &handle
, &sample
);
7265 perf_output_end(&handle
);
7268 static void perf_event_switch(struct task_struct
*task
,
7269 struct task_struct
*next_prev
, bool sched_in
)
7271 struct perf_switch_event switch_event
;
7273 /* N.B. caller checks nr_switch_events != 0 */
7275 switch_event
= (struct perf_switch_event
){
7277 .next_prev
= next_prev
,
7281 .misc
= sched_in
? 0 : PERF_RECORD_MISC_SWITCH_OUT
,
7284 /* .next_prev_pid */
7285 /* .next_prev_tid */
7289 perf_iterate_sb(perf_event_switch_output
,
7295 * IRQ throttle logging
7298 static void perf_log_throttle(struct perf_event
*event
, int enable
)
7300 struct perf_output_handle handle
;
7301 struct perf_sample_data sample
;
7305 struct perf_event_header header
;
7309 } throttle_event
= {
7311 .type
= PERF_RECORD_THROTTLE
,
7313 .size
= sizeof(throttle_event
),
7315 .time
= perf_event_clock(event
),
7316 .id
= primary_event_id(event
),
7317 .stream_id
= event
->id
,
7321 throttle_event
.header
.type
= PERF_RECORD_UNTHROTTLE
;
7323 perf_event_header__init_id(&throttle_event
.header
, &sample
, event
);
7325 ret
= perf_output_begin(&handle
, event
,
7326 throttle_event
.header
.size
);
7330 perf_output_put(&handle
, throttle_event
);
7331 perf_event__output_id_sample(event
, &handle
, &sample
);
7332 perf_output_end(&handle
);
7335 void perf_event_itrace_started(struct perf_event
*event
)
7337 event
->attach_state
|= PERF_ATTACH_ITRACE
;
7340 static void perf_log_itrace_start(struct perf_event
*event
)
7342 struct perf_output_handle handle
;
7343 struct perf_sample_data sample
;
7344 struct perf_aux_event
{
7345 struct perf_event_header header
;
7352 event
= event
->parent
;
7354 if (!(event
->pmu
->capabilities
& PERF_PMU_CAP_ITRACE
) ||
7355 event
->attach_state
& PERF_ATTACH_ITRACE
)
7358 rec
.header
.type
= PERF_RECORD_ITRACE_START
;
7359 rec
.header
.misc
= 0;
7360 rec
.header
.size
= sizeof(rec
);
7361 rec
.pid
= perf_event_pid(event
, current
);
7362 rec
.tid
= perf_event_tid(event
, current
);
7364 perf_event_header__init_id(&rec
.header
, &sample
, event
);
7365 ret
= perf_output_begin(&handle
, event
, rec
.header
.size
);
7370 perf_output_put(&handle
, rec
);
7371 perf_event__output_id_sample(event
, &handle
, &sample
);
7373 perf_output_end(&handle
);
7377 __perf_event_account_interrupt(struct perf_event
*event
, int throttle
)
7379 struct hw_perf_event
*hwc
= &event
->hw
;
7383 seq
= __this_cpu_read(perf_throttled_seq
);
7384 if (seq
!= hwc
->interrupts_seq
) {
7385 hwc
->interrupts_seq
= seq
;
7386 hwc
->interrupts
= 1;
7389 if (unlikely(throttle
7390 && hwc
->interrupts
>= max_samples_per_tick
)) {
7391 __this_cpu_inc(perf_throttled_count
);
7392 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS
);
7393 hwc
->interrupts
= MAX_INTERRUPTS
;
7394 perf_log_throttle(event
, 0);
7399 if (event
->attr
.freq
) {
7400 u64 now
= perf_clock();
7401 s64 delta
= now
- hwc
->freq_time_stamp
;
7403 hwc
->freq_time_stamp
= now
;
7405 if (delta
> 0 && delta
< 2*TICK_NSEC
)
7406 perf_adjust_period(event
, delta
, hwc
->last_period
, true);
7412 int perf_event_account_interrupt(struct perf_event
*event
)
7414 return __perf_event_account_interrupt(event
, 1);
7418 * Generic event overflow handling, sampling.
7421 static int __perf_event_overflow(struct perf_event
*event
,
7422 int throttle
, struct perf_sample_data
*data
,
7423 struct pt_regs
*regs
)
7425 int events
= atomic_read(&event
->event_limit
);
7429 * Non-sampling counters might still use the PMI to fold short
7430 * hardware counters, ignore those.
7432 if (unlikely(!is_sampling_event(event
)))
7435 ret
= __perf_event_account_interrupt(event
, throttle
);
7438 * XXX event_limit might not quite work as expected on inherited
7442 event
->pending_kill
= POLL_IN
;
7443 if (events
&& atomic_dec_and_test(&event
->event_limit
)) {
7445 event
->pending_kill
= POLL_HUP
;
7447 perf_event_disable_inatomic(event
);
7450 READ_ONCE(event
->overflow_handler
)(event
, data
, regs
);
7452 if (*perf_event_fasync(event
) && event
->pending_kill
) {
7453 event
->pending_wakeup
= 1;
7454 irq_work_queue(&event
->pending
);
7460 int perf_event_overflow(struct perf_event
*event
,
7461 struct perf_sample_data
*data
,
7462 struct pt_regs
*regs
)
7464 return __perf_event_overflow(event
, 1, data
, regs
);
7468 * Generic software event infrastructure
7471 struct swevent_htable
{
7472 struct swevent_hlist
*swevent_hlist
;
7473 struct mutex hlist_mutex
;
7476 /* Recursion avoidance in each contexts */
7477 int recursion
[PERF_NR_CONTEXTS
];
7480 static DEFINE_PER_CPU(struct swevent_htable
, swevent_htable
);
7483 * We directly increment event->count and keep a second value in
7484 * event->hw.period_left to count intervals. This period event
7485 * is kept in the range [-sample_period, 0] so that we can use the
7489 u64
perf_swevent_set_period(struct perf_event
*event
)
7491 struct hw_perf_event
*hwc
= &event
->hw
;
7492 u64 period
= hwc
->last_period
;
7496 hwc
->last_period
= hwc
->sample_period
;
7499 old
= val
= local64_read(&hwc
->period_left
);
7503 nr
= div64_u64(period
+ val
, period
);
7504 offset
= nr
* period
;
7506 if (local64_cmpxchg(&hwc
->period_left
, old
, val
) != old
)
7512 static void perf_swevent_overflow(struct perf_event
*event
, u64 overflow
,
7513 struct perf_sample_data
*data
,
7514 struct pt_regs
*regs
)
7516 struct hw_perf_event
*hwc
= &event
->hw
;
7520 overflow
= perf_swevent_set_period(event
);
7522 if (hwc
->interrupts
== MAX_INTERRUPTS
)
7525 for (; overflow
; overflow
--) {
7526 if (__perf_event_overflow(event
, throttle
,
7529 * We inhibit the overflow from happening when
7530 * hwc->interrupts == MAX_INTERRUPTS.
7538 static void perf_swevent_event(struct perf_event
*event
, u64 nr
,
7539 struct perf_sample_data
*data
,
7540 struct pt_regs
*regs
)
7542 struct hw_perf_event
*hwc
= &event
->hw
;
7544 local64_add(nr
, &event
->count
);
7549 if (!is_sampling_event(event
))
7552 if ((event
->attr
.sample_type
& PERF_SAMPLE_PERIOD
) && !event
->attr
.freq
) {
7554 return perf_swevent_overflow(event
, 1, data
, regs
);
7556 data
->period
= event
->hw
.last_period
;
7558 if (nr
== 1 && hwc
->sample_period
== 1 && !event
->attr
.freq
)
7559 return perf_swevent_overflow(event
, 1, data
, regs
);
7561 if (local64_add_negative(nr
, &hwc
->period_left
))
7564 perf_swevent_overflow(event
, 0, data
, regs
);
7567 static int perf_exclude_event(struct perf_event
*event
,
7568 struct pt_regs
*regs
)
7570 if (event
->hw
.state
& PERF_HES_STOPPED
)
7574 if (event
->attr
.exclude_user
&& user_mode(regs
))
7577 if (event
->attr
.exclude_kernel
&& !user_mode(regs
))
7584 static int perf_swevent_match(struct perf_event
*event
,
7585 enum perf_type_id type
,
7587 struct perf_sample_data
*data
,
7588 struct pt_regs
*regs
)
7590 if (event
->attr
.type
!= type
)
7593 if (event
->attr
.config
!= event_id
)
7596 if (perf_exclude_event(event
, regs
))
7602 static inline u64
swevent_hash(u64 type
, u32 event_id
)
7604 u64 val
= event_id
| (type
<< 32);
7606 return hash_64(val
, SWEVENT_HLIST_BITS
);
7609 static inline struct hlist_head
*
7610 __find_swevent_head(struct swevent_hlist
*hlist
, u64 type
, u32 event_id
)
7612 u64 hash
= swevent_hash(type
, event_id
);
7614 return &hlist
->heads
[hash
];
7617 /* For the read side: events when they trigger */
7618 static inline struct hlist_head
*
7619 find_swevent_head_rcu(struct swevent_htable
*swhash
, u64 type
, u32 event_id
)
7621 struct swevent_hlist
*hlist
;
7623 hlist
= rcu_dereference(swhash
->swevent_hlist
);
7627 return __find_swevent_head(hlist
, type
, event_id
);
7630 /* For the event head insertion and removal in the hlist */
7631 static inline struct hlist_head
*
7632 find_swevent_head(struct swevent_htable
*swhash
, struct perf_event
*event
)
7634 struct swevent_hlist
*hlist
;
7635 u32 event_id
= event
->attr
.config
;
7636 u64 type
= event
->attr
.type
;
7639 * Event scheduling is always serialized against hlist allocation
7640 * and release. Which makes the protected version suitable here.
7641 * The context lock guarantees that.
7643 hlist
= rcu_dereference_protected(swhash
->swevent_hlist
,
7644 lockdep_is_held(&event
->ctx
->lock
));
7648 return __find_swevent_head(hlist
, type
, event_id
);
7651 static void do_perf_sw_event(enum perf_type_id type
, u32 event_id
,
7653 struct perf_sample_data
*data
,
7654 struct pt_regs
*regs
)
7656 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7657 struct perf_event
*event
;
7658 struct hlist_head
*head
;
7661 head
= find_swevent_head_rcu(swhash
, type
, event_id
);
7665 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
7666 if (perf_swevent_match(event
, type
, event_id
, data
, regs
))
7667 perf_swevent_event(event
, nr
, data
, regs
);
7673 DEFINE_PER_CPU(struct pt_regs
, __perf_regs
[4]);
7675 int perf_swevent_get_recursion_context(void)
7677 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7679 return get_recursion_context(swhash
->recursion
);
7681 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context
);
7683 void perf_swevent_put_recursion_context(int rctx
)
7685 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7687 put_recursion_context(swhash
->recursion
, rctx
);
7690 void ___perf_sw_event(u32 event_id
, u64 nr
, struct pt_regs
*regs
, u64 addr
)
7692 struct perf_sample_data data
;
7694 if (WARN_ON_ONCE(!regs
))
7697 perf_sample_data_init(&data
, addr
, 0);
7698 do_perf_sw_event(PERF_TYPE_SOFTWARE
, event_id
, nr
, &data
, regs
);
7701 void __perf_sw_event(u32 event_id
, u64 nr
, struct pt_regs
*regs
, u64 addr
)
7705 preempt_disable_notrace();
7706 rctx
= perf_swevent_get_recursion_context();
7707 if (unlikely(rctx
< 0))
7710 ___perf_sw_event(event_id
, nr
, regs
, addr
);
7712 perf_swevent_put_recursion_context(rctx
);
7714 preempt_enable_notrace();
7717 static void perf_swevent_read(struct perf_event
*event
)
7721 static int perf_swevent_add(struct perf_event
*event
, int flags
)
7723 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7724 struct hw_perf_event
*hwc
= &event
->hw
;
7725 struct hlist_head
*head
;
7727 if (is_sampling_event(event
)) {
7728 hwc
->last_period
= hwc
->sample_period
;
7729 perf_swevent_set_period(event
);
7732 hwc
->state
= !(flags
& PERF_EF_START
);
7734 head
= find_swevent_head(swhash
, event
);
7735 if (WARN_ON_ONCE(!head
))
7738 hlist_add_head_rcu(&event
->hlist_entry
, head
);
7739 perf_event_update_userpage(event
);
7744 static void perf_swevent_del(struct perf_event
*event
, int flags
)
7746 hlist_del_rcu(&event
->hlist_entry
);
7749 static void perf_swevent_start(struct perf_event
*event
, int flags
)
7751 event
->hw
.state
= 0;
7754 static void perf_swevent_stop(struct perf_event
*event
, int flags
)
7756 event
->hw
.state
= PERF_HES_STOPPED
;
7759 /* Deref the hlist from the update side */
7760 static inline struct swevent_hlist
*
7761 swevent_hlist_deref(struct swevent_htable
*swhash
)
7763 return rcu_dereference_protected(swhash
->swevent_hlist
,
7764 lockdep_is_held(&swhash
->hlist_mutex
));
7767 static void swevent_hlist_release(struct swevent_htable
*swhash
)
7769 struct swevent_hlist
*hlist
= swevent_hlist_deref(swhash
);
7774 RCU_INIT_POINTER(swhash
->swevent_hlist
, NULL
);
7775 kfree_rcu(hlist
, rcu_head
);
7778 static void swevent_hlist_put_cpu(int cpu
)
7780 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
7782 mutex_lock(&swhash
->hlist_mutex
);
7784 if (!--swhash
->hlist_refcount
)
7785 swevent_hlist_release(swhash
);
7787 mutex_unlock(&swhash
->hlist_mutex
);
7790 static void swevent_hlist_put(void)
7794 for_each_possible_cpu(cpu
)
7795 swevent_hlist_put_cpu(cpu
);
7798 static int swevent_hlist_get_cpu(int cpu
)
7800 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
7803 mutex_lock(&swhash
->hlist_mutex
);
7804 if (!swevent_hlist_deref(swhash
) &&
7805 cpumask_test_cpu(cpu
, perf_online_mask
)) {
7806 struct swevent_hlist
*hlist
;
7808 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
7813 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
7815 swhash
->hlist_refcount
++;
7817 mutex_unlock(&swhash
->hlist_mutex
);
7822 static int swevent_hlist_get(void)
7824 int err
, cpu
, failed_cpu
;
7826 mutex_lock(&pmus_lock
);
7827 for_each_possible_cpu(cpu
) {
7828 err
= swevent_hlist_get_cpu(cpu
);
7834 mutex_unlock(&pmus_lock
);
7837 for_each_possible_cpu(cpu
) {
7838 if (cpu
== failed_cpu
)
7840 swevent_hlist_put_cpu(cpu
);
7842 mutex_unlock(&pmus_lock
);
7846 struct static_key perf_swevent_enabled
[PERF_COUNT_SW_MAX
];
7848 static void sw_perf_event_destroy(struct perf_event
*event
)
7850 u64 event_id
= event
->attr
.config
;
7852 WARN_ON(event
->parent
);
7854 static_key_slow_dec(&perf_swevent_enabled
[event_id
]);
7855 swevent_hlist_put();
7858 static int perf_swevent_init(struct perf_event
*event
)
7860 u64 event_id
= event
->attr
.config
;
7862 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
7866 * no branch sampling for software events
7868 if (has_branch_stack(event
))
7872 case PERF_COUNT_SW_CPU_CLOCK
:
7873 case PERF_COUNT_SW_TASK_CLOCK
:
7880 if (event_id
>= PERF_COUNT_SW_MAX
)
7883 if (!event
->parent
) {
7886 err
= swevent_hlist_get();
7890 static_key_slow_inc(&perf_swevent_enabled
[event_id
]);
7891 event
->destroy
= sw_perf_event_destroy
;
7897 static struct pmu perf_swevent
= {
7898 .task_ctx_nr
= perf_sw_context
,
7900 .capabilities
= PERF_PMU_CAP_NO_NMI
,
7902 .event_init
= perf_swevent_init
,
7903 .add
= perf_swevent_add
,
7904 .del
= perf_swevent_del
,
7905 .start
= perf_swevent_start
,
7906 .stop
= perf_swevent_stop
,
7907 .read
= perf_swevent_read
,
7910 #ifdef CONFIG_EVENT_TRACING
7912 static int perf_tp_filter_match(struct perf_event
*event
,
7913 struct perf_sample_data
*data
)
7915 void *record
= data
->raw
->frag
.data
;
7917 /* only top level events have filters set */
7919 event
= event
->parent
;
7921 if (likely(!event
->filter
) || filter_match_preds(event
->filter
, record
))
7926 static int perf_tp_event_match(struct perf_event
*event
,
7927 struct perf_sample_data
*data
,
7928 struct pt_regs
*regs
)
7930 if (event
->hw
.state
& PERF_HES_STOPPED
)
7933 * All tracepoints are from kernel-space.
7935 if (event
->attr
.exclude_kernel
)
7938 if (!perf_tp_filter_match(event
, data
))
7944 void perf_trace_run_bpf_submit(void *raw_data
, int size
, int rctx
,
7945 struct trace_event_call
*call
, u64 count
,
7946 struct pt_regs
*regs
, struct hlist_head
*head
,
7947 struct task_struct
*task
)
7949 struct bpf_prog
*prog
= call
->prog
;
7952 *(struct pt_regs
**)raw_data
= regs
;
7953 if (!trace_call_bpf(prog
, raw_data
) || hlist_empty(head
)) {
7954 perf_swevent_put_recursion_context(rctx
);
7958 perf_tp_event(call
->event
.type
, count
, raw_data
, size
, regs
, head
,
7961 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit
);
7963 void perf_tp_event(u16 event_type
, u64 count
, void *record
, int entry_size
,
7964 struct pt_regs
*regs
, struct hlist_head
*head
, int rctx
,
7965 struct task_struct
*task
, struct perf_event
*event
)
7967 struct perf_sample_data data
;
7969 struct perf_raw_record raw
= {
7976 perf_sample_data_init(&data
, 0, 0);
7979 perf_trace_buf_update(record
, event_type
);
7981 /* Use the given event instead of the hlist */
7983 if (perf_tp_event_match(event
, &data
, regs
))
7984 perf_swevent_event(event
, count
, &data
, regs
);
7986 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
7987 if (perf_tp_event_match(event
, &data
, regs
))
7988 perf_swevent_event(event
, count
, &data
, regs
);
7993 * If we got specified a target task, also iterate its context and
7994 * deliver this event there too.
7996 if (task
&& task
!= current
) {
7997 struct perf_event_context
*ctx
;
7998 struct trace_entry
*entry
= record
;
8001 ctx
= rcu_dereference(task
->perf_event_ctxp
[perf_sw_context
]);
8005 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
8006 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
8008 if (event
->attr
.config
!= entry
->type
)
8010 if (perf_tp_event_match(event
, &data
, regs
))
8011 perf_swevent_event(event
, count
, &data
, regs
);
8017 perf_swevent_put_recursion_context(rctx
);
8019 EXPORT_SYMBOL_GPL(perf_tp_event
);
8021 static void tp_perf_event_destroy(struct perf_event
*event
)
8023 perf_trace_destroy(event
);
8026 static int perf_tp_event_init(struct perf_event
*event
)
8030 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
8034 * no branch sampling for tracepoint events
8036 if (has_branch_stack(event
))
8039 err
= perf_trace_init(event
);
8043 event
->destroy
= tp_perf_event_destroy
;
8048 static struct pmu perf_tracepoint
= {
8049 .task_ctx_nr
= perf_sw_context
,
8051 .event_init
= perf_tp_event_init
,
8052 .add
= perf_trace_add
,
8053 .del
= perf_trace_del
,
8054 .start
= perf_swevent_start
,
8055 .stop
= perf_swevent_stop
,
8056 .read
= perf_swevent_read
,
8059 static inline void perf_tp_register(void)
8061 perf_pmu_register(&perf_tracepoint
, "tracepoint", PERF_TYPE_TRACEPOINT
);
8064 static void perf_event_free_filter(struct perf_event
*event
)
8066 ftrace_profile_free_filter(event
);
8069 #ifdef CONFIG_BPF_SYSCALL
8070 static void bpf_overflow_handler(struct perf_event
*event
,
8071 struct perf_sample_data
*data
,
8072 struct pt_regs
*regs
)
8074 struct bpf_perf_event_data_kern ctx
= {
8081 if (unlikely(__this_cpu_inc_return(bpf_prog_active
) != 1))
8084 ret
= BPF_PROG_RUN(event
->prog
, &ctx
);
8087 __this_cpu_dec(bpf_prog_active
);
8092 event
->orig_overflow_handler(event
, data
, regs
);
8095 static int perf_event_set_bpf_handler(struct perf_event
*event
, u32 prog_fd
)
8097 struct bpf_prog
*prog
;
8099 if (event
->overflow_handler_context
)
8100 /* hw breakpoint or kernel counter */
8106 prog
= bpf_prog_get_type(prog_fd
, BPF_PROG_TYPE_PERF_EVENT
);
8108 return PTR_ERR(prog
);
8111 event
->orig_overflow_handler
= READ_ONCE(event
->overflow_handler
);
8112 WRITE_ONCE(event
->overflow_handler
, bpf_overflow_handler
);
8116 static void perf_event_free_bpf_handler(struct perf_event
*event
)
8118 struct bpf_prog
*prog
= event
->prog
;
8123 WRITE_ONCE(event
->overflow_handler
, event
->orig_overflow_handler
);
8128 static int perf_event_set_bpf_handler(struct perf_event
*event
, u32 prog_fd
)
8132 static void perf_event_free_bpf_handler(struct perf_event
*event
)
8137 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
)
8139 bool is_kprobe
, is_tracepoint
, is_syscall_tp
;
8140 struct bpf_prog
*prog
;
8142 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
8143 return perf_event_set_bpf_handler(event
, prog_fd
);
8145 if (event
->tp_event
->prog
)
8148 is_kprobe
= event
->tp_event
->flags
& TRACE_EVENT_FL_UKPROBE
;
8149 is_tracepoint
= event
->tp_event
->flags
& TRACE_EVENT_FL_TRACEPOINT
;
8150 is_syscall_tp
= is_syscall_trace_event(event
->tp_event
);
8151 if (!is_kprobe
&& !is_tracepoint
&& !is_syscall_tp
)
8152 /* bpf programs can only be attached to u/kprobe or tracepoint */
8155 prog
= bpf_prog_get(prog_fd
);
8157 return PTR_ERR(prog
);
8159 if ((is_kprobe
&& prog
->type
!= BPF_PROG_TYPE_KPROBE
) ||
8160 (is_tracepoint
&& prog
->type
!= BPF_PROG_TYPE_TRACEPOINT
) ||
8161 (is_syscall_tp
&& prog
->type
!= BPF_PROG_TYPE_TRACEPOINT
)) {
8162 /* valid fd, but invalid bpf program type */
8167 if (is_tracepoint
|| is_syscall_tp
) {
8168 int off
= trace_event_get_offsets(event
->tp_event
);
8170 if (prog
->aux
->max_ctx_offset
> off
) {
8175 event
->tp_event
->prog
= prog
;
8176 event
->tp_event
->bpf_prog_owner
= event
;
8181 static void perf_event_free_bpf_prog(struct perf_event
*event
)
8183 struct bpf_prog
*prog
;
8185 perf_event_free_bpf_handler(event
);
8187 if (!event
->tp_event
)
8190 prog
= event
->tp_event
->prog
;
8191 if (prog
&& event
->tp_event
->bpf_prog_owner
== event
) {
8192 event
->tp_event
->prog
= NULL
;
8199 static inline void perf_tp_register(void)
8203 static void perf_event_free_filter(struct perf_event
*event
)
8207 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
)
8212 static void perf_event_free_bpf_prog(struct perf_event
*event
)
8215 #endif /* CONFIG_EVENT_TRACING */
8217 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8218 void perf_bp_event(struct perf_event
*bp
, void *data
)
8220 struct perf_sample_data sample
;
8221 struct pt_regs
*regs
= data
;
8223 perf_sample_data_init(&sample
, bp
->attr
.bp_addr
, 0);
8225 if (!bp
->hw
.state
&& !perf_exclude_event(bp
, regs
))
8226 perf_swevent_event(bp
, 1, &sample
, regs
);
8231 * Allocate a new address filter
8233 static struct perf_addr_filter
*
8234 perf_addr_filter_new(struct perf_event
*event
, struct list_head
*filters
)
8236 int node
= cpu_to_node(event
->cpu
== -1 ? 0 : event
->cpu
);
8237 struct perf_addr_filter
*filter
;
8239 filter
= kzalloc_node(sizeof(*filter
), GFP_KERNEL
, node
);
8243 INIT_LIST_HEAD(&filter
->entry
);
8244 list_add_tail(&filter
->entry
, filters
);
8249 static void free_filters_list(struct list_head
*filters
)
8251 struct perf_addr_filter
*filter
, *iter
;
8253 list_for_each_entry_safe(filter
, iter
, filters
, entry
) {
8255 iput(filter
->inode
);
8256 list_del(&filter
->entry
);
8262 * Free existing address filters and optionally install new ones
8264 static void perf_addr_filters_splice(struct perf_event
*event
,
8265 struct list_head
*head
)
8267 unsigned long flags
;
8270 if (!has_addr_filter(event
))
8273 /* don't bother with children, they don't have their own filters */
8277 raw_spin_lock_irqsave(&event
->addr_filters
.lock
, flags
);
8279 list_splice_init(&event
->addr_filters
.list
, &list
);
8281 list_splice(head
, &event
->addr_filters
.list
);
8283 raw_spin_unlock_irqrestore(&event
->addr_filters
.lock
, flags
);
8285 free_filters_list(&list
);
8289 * Scan through mm's vmas and see if one of them matches the
8290 * @filter; if so, adjust filter's address range.
8291 * Called with mm::mmap_sem down for reading.
8293 static unsigned long perf_addr_filter_apply(struct perf_addr_filter
*filter
,
8294 struct mm_struct
*mm
)
8296 struct vm_area_struct
*vma
;
8298 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
8299 struct file
*file
= vma
->vm_file
;
8300 unsigned long off
= vma
->vm_pgoff
<< PAGE_SHIFT
;
8301 unsigned long vma_size
= vma
->vm_end
- vma
->vm_start
;
8306 if (!perf_addr_filter_match(filter
, file
, off
, vma_size
))
8309 return vma
->vm_start
;
8316 * Update event's address range filters based on the
8317 * task's existing mappings, if any.
8319 static void perf_event_addr_filters_apply(struct perf_event
*event
)
8321 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
8322 struct task_struct
*task
= READ_ONCE(event
->ctx
->task
);
8323 struct perf_addr_filter
*filter
;
8324 struct mm_struct
*mm
= NULL
;
8325 unsigned int count
= 0;
8326 unsigned long flags
;
8329 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8330 * will stop on the parent's child_mutex that our caller is also holding
8332 if (task
== TASK_TOMBSTONE
)
8335 if (!ifh
->nr_file_filters
)
8338 mm
= get_task_mm(event
->ctx
->task
);
8342 down_read(&mm
->mmap_sem
);
8344 raw_spin_lock_irqsave(&ifh
->lock
, flags
);
8345 list_for_each_entry(filter
, &ifh
->list
, entry
) {
8346 event
->addr_filters_offs
[count
] = 0;
8349 * Adjust base offset if the filter is associated to a binary
8350 * that needs to be mapped:
8353 event
->addr_filters_offs
[count
] =
8354 perf_addr_filter_apply(filter
, mm
);
8359 event
->addr_filters_gen
++;
8360 raw_spin_unlock_irqrestore(&ifh
->lock
, flags
);
8362 up_read(&mm
->mmap_sem
);
8367 perf_event_stop(event
, 1);
8371 * Address range filtering: limiting the data to certain
8372 * instruction address ranges. Filters are ioctl()ed to us from
8373 * userspace as ascii strings.
8375 * Filter string format:
8378 * where ACTION is one of the
8379 * * "filter": limit the trace to this region
8380 * * "start": start tracing from this address
8381 * * "stop": stop tracing at this address/region;
8383 * * for kernel addresses: <start address>[/<size>]
8384 * * for object files: <start address>[/<size>]@</path/to/object/file>
8386 * if <size> is not specified, the range is treated as a single address.
8400 IF_STATE_ACTION
= 0,
8405 static const match_table_t if_tokens
= {
8406 { IF_ACT_FILTER
, "filter" },
8407 { IF_ACT_START
, "start" },
8408 { IF_ACT_STOP
, "stop" },
8409 { IF_SRC_FILE
, "%u/%u@%s" },
8410 { IF_SRC_KERNEL
, "%u/%u" },
8411 { IF_SRC_FILEADDR
, "%u@%s" },
8412 { IF_SRC_KERNELADDR
, "%u" },
8413 { IF_ACT_NONE
, NULL
},
8417 * Address filter string parser
8420 perf_event_parse_addr_filter(struct perf_event
*event
, char *fstr
,
8421 struct list_head
*filters
)
8423 struct perf_addr_filter
*filter
= NULL
;
8424 char *start
, *orig
, *filename
= NULL
;
8426 substring_t args
[MAX_OPT_ARGS
];
8427 int state
= IF_STATE_ACTION
, token
;
8428 unsigned int kernel
= 0;
8431 orig
= fstr
= kstrdup(fstr
, GFP_KERNEL
);
8435 while ((start
= strsep(&fstr
, " ,\n")) != NULL
) {
8441 /* filter definition begins */
8442 if (state
== IF_STATE_ACTION
) {
8443 filter
= perf_addr_filter_new(event
, filters
);
8448 token
= match_token(start
, if_tokens
, args
);
8455 if (state
!= IF_STATE_ACTION
)
8458 state
= IF_STATE_SOURCE
;
8461 case IF_SRC_KERNELADDR
:
8465 case IF_SRC_FILEADDR
:
8467 if (state
!= IF_STATE_SOURCE
)
8470 if (token
== IF_SRC_FILE
|| token
== IF_SRC_KERNEL
)
8474 ret
= kstrtoul(args
[0].from
, 0, &filter
->offset
);
8478 if (filter
->range
) {
8480 ret
= kstrtoul(args
[1].from
, 0, &filter
->size
);
8485 if (token
== IF_SRC_FILE
|| token
== IF_SRC_FILEADDR
) {
8486 int fpos
= filter
->range
? 2 : 1;
8488 filename
= match_strdup(&args
[fpos
]);
8495 state
= IF_STATE_END
;
8503 * Filter definition is fully parsed, validate and install it.
8504 * Make sure that it doesn't contradict itself or the event's
8507 if (state
== IF_STATE_END
) {
8509 if (kernel
&& event
->attr
.exclude_kernel
)
8517 * For now, we only support file-based filters
8518 * in per-task events; doing so for CPU-wide
8519 * events requires additional context switching
8520 * trickery, since same object code will be
8521 * mapped at different virtual addresses in
8522 * different processes.
8525 if (!event
->ctx
->task
)
8526 goto fail_free_name
;
8528 /* look up the path and grab its inode */
8529 ret
= kern_path(filename
, LOOKUP_FOLLOW
, &path
);
8531 goto fail_free_name
;
8533 filter
->inode
= igrab(d_inode(path
.dentry
));
8539 if (!filter
->inode
||
8540 !S_ISREG(filter
->inode
->i_mode
))
8541 /* free_filters_list() will iput() */
8544 event
->addr_filters
.nr_file_filters
++;
8547 /* ready to consume more filters */
8548 state
= IF_STATE_ACTION
;
8553 if (state
!= IF_STATE_ACTION
)
8563 free_filters_list(filters
);
8570 perf_event_set_addr_filter(struct perf_event
*event
, char *filter_str
)
8576 * Since this is called in perf_ioctl() path, we're already holding
8579 lockdep_assert_held(&event
->ctx
->mutex
);
8581 if (WARN_ON_ONCE(event
->parent
))
8584 ret
= perf_event_parse_addr_filter(event
, filter_str
, &filters
);
8586 goto fail_clear_files
;
8588 ret
= event
->pmu
->addr_filters_validate(&filters
);
8590 goto fail_free_filters
;
8592 /* remove existing filters, if any */
8593 perf_addr_filters_splice(event
, &filters
);
8595 /* install new filters */
8596 perf_event_for_each_child(event
, perf_event_addr_filters_apply
);
8601 free_filters_list(&filters
);
8604 event
->addr_filters
.nr_file_filters
= 0;
8609 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
8614 if ((event
->attr
.type
!= PERF_TYPE_TRACEPOINT
||
8615 !IS_ENABLED(CONFIG_EVENT_TRACING
)) &&
8616 !has_addr_filter(event
))
8619 filter_str
= strndup_user(arg
, PAGE_SIZE
);
8620 if (IS_ERR(filter_str
))
8621 return PTR_ERR(filter_str
);
8623 if (IS_ENABLED(CONFIG_EVENT_TRACING
) &&
8624 event
->attr
.type
== PERF_TYPE_TRACEPOINT
)
8625 ret
= ftrace_profile_set_filter(event
, event
->attr
.config
,
8627 else if (has_addr_filter(event
))
8628 ret
= perf_event_set_addr_filter(event
, filter_str
);
8635 * hrtimer based swevent callback
8638 static enum hrtimer_restart
perf_swevent_hrtimer(struct hrtimer
*hrtimer
)
8640 enum hrtimer_restart ret
= HRTIMER_RESTART
;
8641 struct perf_sample_data data
;
8642 struct pt_regs
*regs
;
8643 struct perf_event
*event
;
8646 event
= container_of(hrtimer
, struct perf_event
, hw
.hrtimer
);
8648 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
8649 return HRTIMER_NORESTART
;
8651 event
->pmu
->read(event
);
8653 perf_sample_data_init(&data
, 0, event
->hw
.last_period
);
8654 regs
= get_irq_regs();
8656 if (regs
&& !perf_exclude_event(event
, regs
)) {
8657 if (!(event
->attr
.exclude_idle
&& is_idle_task(current
)))
8658 if (__perf_event_overflow(event
, 1, &data
, regs
))
8659 ret
= HRTIMER_NORESTART
;
8662 period
= max_t(u64
, 10000, event
->hw
.sample_period
);
8663 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
8668 static void perf_swevent_start_hrtimer(struct perf_event
*event
)
8670 struct hw_perf_event
*hwc
= &event
->hw
;
8673 if (!is_sampling_event(event
))
8676 period
= local64_read(&hwc
->period_left
);
8681 local64_set(&hwc
->period_left
, 0);
8683 period
= max_t(u64
, 10000, hwc
->sample_period
);
8685 hrtimer_start(&hwc
->hrtimer
, ns_to_ktime(period
),
8686 HRTIMER_MODE_REL_PINNED
);
8689 static void perf_swevent_cancel_hrtimer(struct perf_event
*event
)
8691 struct hw_perf_event
*hwc
= &event
->hw
;
8693 if (is_sampling_event(event
)) {
8694 ktime_t remaining
= hrtimer_get_remaining(&hwc
->hrtimer
);
8695 local64_set(&hwc
->period_left
, ktime_to_ns(remaining
));
8697 hrtimer_cancel(&hwc
->hrtimer
);
8701 static void perf_swevent_init_hrtimer(struct perf_event
*event
)
8703 struct hw_perf_event
*hwc
= &event
->hw
;
8705 if (!is_sampling_event(event
))
8708 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
8709 hwc
->hrtimer
.function
= perf_swevent_hrtimer
;
8712 * Since hrtimers have a fixed rate, we can do a static freq->period
8713 * mapping and avoid the whole period adjust feedback stuff.
8715 if (event
->attr
.freq
) {
8716 long freq
= event
->attr
.sample_freq
;
8718 event
->attr
.sample_period
= NSEC_PER_SEC
/ freq
;
8719 hwc
->sample_period
= event
->attr
.sample_period
;
8720 local64_set(&hwc
->period_left
, hwc
->sample_period
);
8721 hwc
->last_period
= hwc
->sample_period
;
8722 event
->attr
.freq
= 0;
8727 * Software event: cpu wall time clock
8730 static void cpu_clock_event_update(struct perf_event
*event
)
8735 now
= local_clock();
8736 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
8737 local64_add(now
- prev
, &event
->count
);
8740 static void cpu_clock_event_start(struct perf_event
*event
, int flags
)
8742 local64_set(&event
->hw
.prev_count
, local_clock());
8743 perf_swevent_start_hrtimer(event
);
8746 static void cpu_clock_event_stop(struct perf_event
*event
, int flags
)
8748 perf_swevent_cancel_hrtimer(event
);
8749 cpu_clock_event_update(event
);
8752 static int cpu_clock_event_add(struct perf_event
*event
, int flags
)
8754 if (flags
& PERF_EF_START
)
8755 cpu_clock_event_start(event
, flags
);
8756 perf_event_update_userpage(event
);
8761 static void cpu_clock_event_del(struct perf_event
*event
, int flags
)
8763 cpu_clock_event_stop(event
, flags
);
8766 static void cpu_clock_event_read(struct perf_event
*event
)
8768 cpu_clock_event_update(event
);
8771 static int cpu_clock_event_init(struct perf_event
*event
)
8773 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
8776 if (event
->attr
.config
!= PERF_COUNT_SW_CPU_CLOCK
)
8780 * no branch sampling for software events
8782 if (has_branch_stack(event
))
8785 perf_swevent_init_hrtimer(event
);
8790 static struct pmu perf_cpu_clock
= {
8791 .task_ctx_nr
= perf_sw_context
,
8793 .capabilities
= PERF_PMU_CAP_NO_NMI
,
8795 .event_init
= cpu_clock_event_init
,
8796 .add
= cpu_clock_event_add
,
8797 .del
= cpu_clock_event_del
,
8798 .start
= cpu_clock_event_start
,
8799 .stop
= cpu_clock_event_stop
,
8800 .read
= cpu_clock_event_read
,
8804 * Software event: task time clock
8807 static void task_clock_event_update(struct perf_event
*event
, u64 now
)
8812 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
8814 local64_add(delta
, &event
->count
);
8817 static void task_clock_event_start(struct perf_event
*event
, int flags
)
8819 local64_set(&event
->hw
.prev_count
, event
->ctx
->time
);
8820 perf_swevent_start_hrtimer(event
);
8823 static void task_clock_event_stop(struct perf_event
*event
, int flags
)
8825 perf_swevent_cancel_hrtimer(event
);
8826 task_clock_event_update(event
, event
->ctx
->time
);
8829 static int task_clock_event_add(struct perf_event
*event
, int flags
)
8831 if (flags
& PERF_EF_START
)
8832 task_clock_event_start(event
, flags
);
8833 perf_event_update_userpage(event
);
8838 static void task_clock_event_del(struct perf_event
*event
, int flags
)
8840 task_clock_event_stop(event
, PERF_EF_UPDATE
);
8843 static void task_clock_event_read(struct perf_event
*event
)
8845 u64 now
= perf_clock();
8846 u64 delta
= now
- event
->ctx
->timestamp
;
8847 u64 time
= event
->ctx
->time
+ delta
;
8849 task_clock_event_update(event
, time
);
8852 static int task_clock_event_init(struct perf_event
*event
)
8854 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
8857 if (event
->attr
.config
!= PERF_COUNT_SW_TASK_CLOCK
)
8861 * no branch sampling for software events
8863 if (has_branch_stack(event
))
8866 perf_swevent_init_hrtimer(event
);
8871 static struct pmu perf_task_clock
= {
8872 .task_ctx_nr
= perf_sw_context
,
8874 .capabilities
= PERF_PMU_CAP_NO_NMI
,
8876 .event_init
= task_clock_event_init
,
8877 .add
= task_clock_event_add
,
8878 .del
= task_clock_event_del
,
8879 .start
= task_clock_event_start
,
8880 .stop
= task_clock_event_stop
,
8881 .read
= task_clock_event_read
,
8884 static void perf_pmu_nop_void(struct pmu
*pmu
)
8888 static void perf_pmu_nop_txn(struct pmu
*pmu
, unsigned int flags
)
8892 static int perf_pmu_nop_int(struct pmu
*pmu
)
8897 static DEFINE_PER_CPU(unsigned int, nop_txn_flags
);
8899 static void perf_pmu_start_txn(struct pmu
*pmu
, unsigned int flags
)
8901 __this_cpu_write(nop_txn_flags
, flags
);
8903 if (flags
& ~PERF_PMU_TXN_ADD
)
8906 perf_pmu_disable(pmu
);
8909 static int perf_pmu_commit_txn(struct pmu
*pmu
)
8911 unsigned int flags
= __this_cpu_read(nop_txn_flags
);
8913 __this_cpu_write(nop_txn_flags
, 0);
8915 if (flags
& ~PERF_PMU_TXN_ADD
)
8918 perf_pmu_enable(pmu
);
8922 static void perf_pmu_cancel_txn(struct pmu
*pmu
)
8924 unsigned int flags
= __this_cpu_read(nop_txn_flags
);
8926 __this_cpu_write(nop_txn_flags
, 0);
8928 if (flags
& ~PERF_PMU_TXN_ADD
)
8931 perf_pmu_enable(pmu
);
8934 static int perf_event_idx_default(struct perf_event
*event
)
8940 * Ensures all contexts with the same task_ctx_nr have the same
8941 * pmu_cpu_context too.
8943 static struct perf_cpu_context __percpu
*find_pmu_context(int ctxn
)
8950 list_for_each_entry(pmu
, &pmus
, entry
) {
8951 if (pmu
->task_ctx_nr
== ctxn
)
8952 return pmu
->pmu_cpu_context
;
8958 static void free_pmu_context(struct pmu
*pmu
)
8961 * Static contexts such as perf_sw_context have a global lifetime
8962 * and may be shared between different PMUs. Avoid freeing them
8963 * when a single PMU is going away.
8965 if (pmu
->task_ctx_nr
> perf_invalid_context
)
8968 mutex_lock(&pmus_lock
);
8969 free_percpu(pmu
->pmu_cpu_context
);
8970 mutex_unlock(&pmus_lock
);
8974 * Let userspace know that this PMU supports address range filtering:
8976 static ssize_t
nr_addr_filters_show(struct device
*dev
,
8977 struct device_attribute
*attr
,
8980 struct pmu
*pmu
= dev_get_drvdata(dev
);
8982 return snprintf(page
, PAGE_SIZE
- 1, "%d\n", pmu
->nr_addr_filters
);
8984 DEVICE_ATTR_RO(nr_addr_filters
);
8986 static struct idr pmu_idr
;
8989 type_show(struct device
*dev
, struct device_attribute
*attr
, char *page
)
8991 struct pmu
*pmu
= dev_get_drvdata(dev
);
8993 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->type
);
8995 static DEVICE_ATTR_RO(type
);
8998 perf_event_mux_interval_ms_show(struct device
*dev
,
8999 struct device_attribute
*attr
,
9002 struct pmu
*pmu
= dev_get_drvdata(dev
);
9004 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->hrtimer_interval_ms
);
9007 static DEFINE_MUTEX(mux_interval_mutex
);
9010 perf_event_mux_interval_ms_store(struct device
*dev
,
9011 struct device_attribute
*attr
,
9012 const char *buf
, size_t count
)
9014 struct pmu
*pmu
= dev_get_drvdata(dev
);
9015 int timer
, cpu
, ret
;
9017 ret
= kstrtoint(buf
, 0, &timer
);
9024 /* same value, noting to do */
9025 if (timer
== pmu
->hrtimer_interval_ms
)
9028 mutex_lock(&mux_interval_mutex
);
9029 pmu
->hrtimer_interval_ms
= timer
;
9031 /* update all cpuctx for this PMU */
9033 for_each_online_cpu(cpu
) {
9034 struct perf_cpu_context
*cpuctx
;
9035 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
9036 cpuctx
->hrtimer_interval
= ns_to_ktime(NSEC_PER_MSEC
* timer
);
9038 cpu_function_call(cpu
,
9039 (remote_function_f
)perf_mux_hrtimer_restart
, cpuctx
);
9042 mutex_unlock(&mux_interval_mutex
);
9046 static DEVICE_ATTR_RW(perf_event_mux_interval_ms
);
9048 static struct attribute
*pmu_dev_attrs
[] = {
9049 &dev_attr_type
.attr
,
9050 &dev_attr_perf_event_mux_interval_ms
.attr
,
9053 ATTRIBUTE_GROUPS(pmu_dev
);
9055 static int pmu_bus_running
;
9056 static struct bus_type pmu_bus
= {
9057 .name
= "event_source",
9058 .dev_groups
= pmu_dev_groups
,
9061 static void pmu_dev_release(struct device
*dev
)
9066 static int pmu_dev_alloc(struct pmu
*pmu
)
9070 pmu
->dev
= kzalloc(sizeof(struct device
), GFP_KERNEL
);
9074 pmu
->dev
->groups
= pmu
->attr_groups
;
9075 device_initialize(pmu
->dev
);
9076 ret
= dev_set_name(pmu
->dev
, "%s", pmu
->name
);
9080 dev_set_drvdata(pmu
->dev
, pmu
);
9081 pmu
->dev
->bus
= &pmu_bus
;
9082 pmu
->dev
->release
= pmu_dev_release
;
9083 ret
= device_add(pmu
->dev
);
9087 /* For PMUs with address filters, throw in an extra attribute: */
9088 if (pmu
->nr_addr_filters
)
9089 ret
= device_create_file(pmu
->dev
, &dev_attr_nr_addr_filters
);
9098 device_del(pmu
->dev
);
9101 put_device(pmu
->dev
);
9105 static struct lock_class_key cpuctx_mutex
;
9106 static struct lock_class_key cpuctx_lock
;
9108 int perf_pmu_register(struct pmu
*pmu
, const char *name
, int type
)
9112 mutex_lock(&pmus_lock
);
9114 pmu
->pmu_disable_count
= alloc_percpu(int);
9115 if (!pmu
->pmu_disable_count
)
9124 type
= idr_alloc(&pmu_idr
, pmu
, PERF_TYPE_MAX
, 0, GFP_KERNEL
);
9132 if (pmu_bus_running
) {
9133 ret
= pmu_dev_alloc(pmu
);
9139 if (pmu
->task_ctx_nr
== perf_hw_context
) {
9140 static int hw_context_taken
= 0;
9143 * Other than systems with heterogeneous CPUs, it never makes
9144 * sense for two PMUs to share perf_hw_context. PMUs which are
9145 * uncore must use perf_invalid_context.
9147 if (WARN_ON_ONCE(hw_context_taken
&&
9148 !(pmu
->capabilities
& PERF_PMU_CAP_HETEROGENEOUS_CPUS
)))
9149 pmu
->task_ctx_nr
= perf_invalid_context
;
9151 hw_context_taken
= 1;
9154 pmu
->pmu_cpu_context
= find_pmu_context(pmu
->task_ctx_nr
);
9155 if (pmu
->pmu_cpu_context
)
9156 goto got_cpu_context
;
9159 pmu
->pmu_cpu_context
= alloc_percpu(struct perf_cpu_context
);
9160 if (!pmu
->pmu_cpu_context
)
9163 for_each_possible_cpu(cpu
) {
9164 struct perf_cpu_context
*cpuctx
;
9166 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
9167 __perf_event_init_context(&cpuctx
->ctx
);
9168 lockdep_set_class(&cpuctx
->ctx
.mutex
, &cpuctx_mutex
);
9169 lockdep_set_class(&cpuctx
->ctx
.lock
, &cpuctx_lock
);
9170 cpuctx
->ctx
.pmu
= pmu
;
9171 cpuctx
->online
= cpumask_test_cpu(cpu
, perf_online_mask
);
9173 __perf_mux_hrtimer_init(cpuctx
, cpu
);
9177 if (!pmu
->start_txn
) {
9178 if (pmu
->pmu_enable
) {
9180 * If we have pmu_enable/pmu_disable calls, install
9181 * transaction stubs that use that to try and batch
9182 * hardware accesses.
9184 pmu
->start_txn
= perf_pmu_start_txn
;
9185 pmu
->commit_txn
= perf_pmu_commit_txn
;
9186 pmu
->cancel_txn
= perf_pmu_cancel_txn
;
9188 pmu
->start_txn
= perf_pmu_nop_txn
;
9189 pmu
->commit_txn
= perf_pmu_nop_int
;
9190 pmu
->cancel_txn
= perf_pmu_nop_void
;
9194 if (!pmu
->pmu_enable
) {
9195 pmu
->pmu_enable
= perf_pmu_nop_void
;
9196 pmu
->pmu_disable
= perf_pmu_nop_void
;
9199 if (!pmu
->event_idx
)
9200 pmu
->event_idx
= perf_event_idx_default
;
9202 list_add_rcu(&pmu
->entry
, &pmus
);
9203 atomic_set(&pmu
->exclusive_cnt
, 0);
9206 mutex_unlock(&pmus_lock
);
9211 device_del(pmu
->dev
);
9212 put_device(pmu
->dev
);
9215 if (pmu
->type
>= PERF_TYPE_MAX
)
9216 idr_remove(&pmu_idr
, pmu
->type
);
9219 free_percpu(pmu
->pmu_disable_count
);
9222 EXPORT_SYMBOL_GPL(perf_pmu_register
);
9224 void perf_pmu_unregister(struct pmu
*pmu
)
9228 mutex_lock(&pmus_lock
);
9229 remove_device
= pmu_bus_running
;
9230 list_del_rcu(&pmu
->entry
);
9231 mutex_unlock(&pmus_lock
);
9234 * We dereference the pmu list under both SRCU and regular RCU, so
9235 * synchronize against both of those.
9237 synchronize_srcu(&pmus_srcu
);
9240 free_percpu(pmu
->pmu_disable_count
);
9241 if (pmu
->type
>= PERF_TYPE_MAX
)
9242 idr_remove(&pmu_idr
, pmu
->type
);
9243 if (remove_device
) {
9244 if (pmu
->nr_addr_filters
)
9245 device_remove_file(pmu
->dev
, &dev_attr_nr_addr_filters
);
9246 device_del(pmu
->dev
);
9247 put_device(pmu
->dev
);
9249 free_pmu_context(pmu
);
9251 EXPORT_SYMBOL_GPL(perf_pmu_unregister
);
9253 static int perf_try_init_event(struct pmu
*pmu
, struct perf_event
*event
)
9255 struct perf_event_context
*ctx
= NULL
;
9258 if (!try_module_get(pmu
->module
))
9261 if (event
->group_leader
!= event
) {
9263 * This ctx->mutex can nest when we're called through
9264 * inheritance. See the perf_event_ctx_lock_nested() comment.
9266 ctx
= perf_event_ctx_lock_nested(event
->group_leader
,
9267 SINGLE_DEPTH_NESTING
);
9272 ret
= pmu
->event_init(event
);
9275 perf_event_ctx_unlock(event
->group_leader
, ctx
);
9278 module_put(pmu
->module
);
9283 static struct pmu
*perf_init_event(struct perf_event
*event
)
9289 idx
= srcu_read_lock(&pmus_srcu
);
9291 /* Try parent's PMU first: */
9292 if (event
->parent
&& event
->parent
->pmu
) {
9293 pmu
= event
->parent
->pmu
;
9294 ret
= perf_try_init_event(pmu
, event
);
9300 pmu
= idr_find(&pmu_idr
, event
->attr
.type
);
9303 ret
= perf_try_init_event(pmu
, event
);
9309 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
9310 ret
= perf_try_init_event(pmu
, event
);
9314 if (ret
!= -ENOENT
) {
9319 pmu
= ERR_PTR(-ENOENT
);
9321 srcu_read_unlock(&pmus_srcu
, idx
);
9326 static void attach_sb_event(struct perf_event
*event
)
9328 struct pmu_event_list
*pel
= per_cpu_ptr(&pmu_sb_events
, event
->cpu
);
9330 raw_spin_lock(&pel
->lock
);
9331 list_add_rcu(&event
->sb_list
, &pel
->list
);
9332 raw_spin_unlock(&pel
->lock
);
9336 * We keep a list of all !task (and therefore per-cpu) events
9337 * that need to receive side-band records.
9339 * This avoids having to scan all the various PMU per-cpu contexts
9342 static void account_pmu_sb_event(struct perf_event
*event
)
9344 if (is_sb_event(event
))
9345 attach_sb_event(event
);
9348 static void account_event_cpu(struct perf_event
*event
, int cpu
)
9353 if (is_cgroup_event(event
))
9354 atomic_inc(&per_cpu(perf_cgroup_events
, cpu
));
9357 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9358 static void account_freq_event_nohz(void)
9360 #ifdef CONFIG_NO_HZ_FULL
9361 /* Lock so we don't race with concurrent unaccount */
9362 spin_lock(&nr_freq_lock
);
9363 if (atomic_inc_return(&nr_freq_events
) == 1)
9364 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS
);
9365 spin_unlock(&nr_freq_lock
);
9369 static void account_freq_event(void)
9371 if (tick_nohz_full_enabled())
9372 account_freq_event_nohz();
9374 atomic_inc(&nr_freq_events
);
9378 static void account_event(struct perf_event
*event
)
9385 if (event
->attach_state
& PERF_ATTACH_TASK
)
9387 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
9388 atomic_inc(&nr_mmap_events
);
9389 if (event
->attr
.comm
)
9390 atomic_inc(&nr_comm_events
);
9391 if (event
->attr
.namespaces
)
9392 atomic_inc(&nr_namespaces_events
);
9393 if (event
->attr
.task
)
9394 atomic_inc(&nr_task_events
);
9395 if (event
->attr
.freq
)
9396 account_freq_event();
9397 if (event
->attr
.context_switch
) {
9398 atomic_inc(&nr_switch_events
);
9401 if (has_branch_stack(event
))
9403 if (is_cgroup_event(event
))
9407 if (atomic_inc_not_zero(&perf_sched_count
))
9410 mutex_lock(&perf_sched_mutex
);
9411 if (!atomic_read(&perf_sched_count
)) {
9412 static_branch_enable(&perf_sched_events
);
9414 * Guarantee that all CPUs observe they key change and
9415 * call the perf scheduling hooks before proceeding to
9416 * install events that need them.
9418 synchronize_sched();
9421 * Now that we have waited for the sync_sched(), allow further
9422 * increments to by-pass the mutex.
9424 atomic_inc(&perf_sched_count
);
9425 mutex_unlock(&perf_sched_mutex
);
9429 account_event_cpu(event
, event
->cpu
);
9431 account_pmu_sb_event(event
);
9435 * Allocate and initialize a event structure
9437 static struct perf_event
*
9438 perf_event_alloc(struct perf_event_attr
*attr
, int cpu
,
9439 struct task_struct
*task
,
9440 struct perf_event
*group_leader
,
9441 struct perf_event
*parent_event
,
9442 perf_overflow_handler_t overflow_handler
,
9443 void *context
, int cgroup_fd
)
9446 struct perf_event
*event
;
9447 struct hw_perf_event
*hwc
;
9450 if ((unsigned)cpu
>= nr_cpu_ids
) {
9451 if (!task
|| cpu
!= -1)
9452 return ERR_PTR(-EINVAL
);
9455 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
9457 return ERR_PTR(-ENOMEM
);
9460 * Single events are their own group leaders, with an
9461 * empty sibling list:
9464 group_leader
= event
;
9466 mutex_init(&event
->child_mutex
);
9467 INIT_LIST_HEAD(&event
->child_list
);
9469 INIT_LIST_HEAD(&event
->group_entry
);
9470 INIT_LIST_HEAD(&event
->event_entry
);
9471 INIT_LIST_HEAD(&event
->sibling_list
);
9472 INIT_LIST_HEAD(&event
->rb_entry
);
9473 INIT_LIST_HEAD(&event
->active_entry
);
9474 INIT_LIST_HEAD(&event
->addr_filters
.list
);
9475 INIT_HLIST_NODE(&event
->hlist_entry
);
9478 init_waitqueue_head(&event
->waitq
);
9479 init_irq_work(&event
->pending
, perf_pending_event
);
9481 mutex_init(&event
->mmap_mutex
);
9482 raw_spin_lock_init(&event
->addr_filters
.lock
);
9484 atomic_long_set(&event
->refcount
, 1);
9486 event
->attr
= *attr
;
9487 event
->group_leader
= group_leader
;
9491 event
->parent
= parent_event
;
9493 event
->ns
= get_pid_ns(task_active_pid_ns(current
));
9494 event
->id
= atomic64_inc_return(&perf_event_id
);
9496 event
->state
= PERF_EVENT_STATE_INACTIVE
;
9499 event
->attach_state
= PERF_ATTACH_TASK
;
9501 * XXX pmu::event_init needs to know what task to account to
9502 * and we cannot use the ctx information because we need the
9503 * pmu before we get a ctx.
9505 event
->hw
.target
= task
;
9508 event
->clock
= &local_clock
;
9510 event
->clock
= parent_event
->clock
;
9512 if (!overflow_handler
&& parent_event
) {
9513 overflow_handler
= parent_event
->overflow_handler
;
9514 context
= parent_event
->overflow_handler_context
;
9515 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9516 if (overflow_handler
== bpf_overflow_handler
) {
9517 struct bpf_prog
*prog
= bpf_prog_inc(parent_event
->prog
);
9520 err
= PTR_ERR(prog
);
9524 event
->orig_overflow_handler
=
9525 parent_event
->orig_overflow_handler
;
9530 if (overflow_handler
) {
9531 event
->overflow_handler
= overflow_handler
;
9532 event
->overflow_handler_context
= context
;
9533 } else if (is_write_backward(event
)){
9534 event
->overflow_handler
= perf_event_output_backward
;
9535 event
->overflow_handler_context
= NULL
;
9537 event
->overflow_handler
= perf_event_output_forward
;
9538 event
->overflow_handler_context
= NULL
;
9541 perf_event__state_init(event
);
9546 hwc
->sample_period
= attr
->sample_period
;
9547 if (attr
->freq
&& attr
->sample_freq
)
9548 hwc
->sample_period
= 1;
9549 hwc
->last_period
= hwc
->sample_period
;
9551 local64_set(&hwc
->period_left
, hwc
->sample_period
);
9554 * We currently do not support PERF_SAMPLE_READ on inherited events.
9555 * See perf_output_read().
9557 if (attr
->inherit
&& (attr
->sample_type
& PERF_SAMPLE_READ
))
9560 if (!has_branch_stack(event
))
9561 event
->attr
.branch_sample_type
= 0;
9563 if (cgroup_fd
!= -1) {
9564 err
= perf_cgroup_connect(cgroup_fd
, event
, attr
, group_leader
);
9569 pmu
= perf_init_event(event
);
9575 err
= exclusive_event_init(event
);
9579 if (has_addr_filter(event
)) {
9580 event
->addr_filters_offs
= kcalloc(pmu
->nr_addr_filters
,
9581 sizeof(unsigned long),
9583 if (!event
->addr_filters_offs
) {
9588 /* force hw sync on the address filters */
9589 event
->addr_filters_gen
= 1;
9592 if (!event
->parent
) {
9593 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
) {
9594 err
= get_callchain_buffers(attr
->sample_max_stack
);
9596 goto err_addr_filters
;
9600 /* symmetric to unaccount_event() in _free_event() */
9601 account_event(event
);
9606 kfree(event
->addr_filters_offs
);
9609 exclusive_event_destroy(event
);
9613 event
->destroy(event
);
9614 module_put(pmu
->module
);
9616 if (is_cgroup_event(event
))
9617 perf_detach_cgroup(event
);
9619 put_pid_ns(event
->ns
);
9622 return ERR_PTR(err
);
9625 static int perf_copy_attr(struct perf_event_attr __user
*uattr
,
9626 struct perf_event_attr
*attr
)
9631 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
9635 * zero the full structure, so that a short copy will be nice.
9637 memset(attr
, 0, sizeof(*attr
));
9639 ret
= get_user(size
, &uattr
->size
);
9643 if (size
> PAGE_SIZE
) /* silly large */
9646 if (!size
) /* abi compat */
9647 size
= PERF_ATTR_SIZE_VER0
;
9649 if (size
< PERF_ATTR_SIZE_VER0
)
9653 * If we're handed a bigger struct than we know of,
9654 * ensure all the unknown bits are 0 - i.e. new
9655 * user-space does not rely on any kernel feature
9656 * extensions we dont know about yet.
9658 if (size
> sizeof(*attr
)) {
9659 unsigned char __user
*addr
;
9660 unsigned char __user
*end
;
9663 addr
= (void __user
*)uattr
+ sizeof(*attr
);
9664 end
= (void __user
*)uattr
+ size
;
9666 for (; addr
< end
; addr
++) {
9667 ret
= get_user(val
, addr
);
9673 size
= sizeof(*attr
);
9676 ret
= copy_from_user(attr
, uattr
, size
);
9682 if (attr
->__reserved_1
)
9685 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
9688 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
9691 if (attr
->sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
9692 u64 mask
= attr
->branch_sample_type
;
9694 /* only using defined bits */
9695 if (mask
& ~(PERF_SAMPLE_BRANCH_MAX
-1))
9698 /* at least one branch bit must be set */
9699 if (!(mask
& ~PERF_SAMPLE_BRANCH_PLM_ALL
))
9702 /* propagate priv level, when not set for branch */
9703 if (!(mask
& PERF_SAMPLE_BRANCH_PLM_ALL
)) {
9705 /* exclude_kernel checked on syscall entry */
9706 if (!attr
->exclude_kernel
)
9707 mask
|= PERF_SAMPLE_BRANCH_KERNEL
;
9709 if (!attr
->exclude_user
)
9710 mask
|= PERF_SAMPLE_BRANCH_USER
;
9712 if (!attr
->exclude_hv
)
9713 mask
|= PERF_SAMPLE_BRANCH_HV
;
9715 * adjust user setting (for HW filter setup)
9717 attr
->branch_sample_type
= mask
;
9719 /* privileged levels capture (kernel, hv): check permissions */
9720 if ((mask
& PERF_SAMPLE_BRANCH_PERM_PLM
)
9721 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
9725 if (attr
->sample_type
& PERF_SAMPLE_REGS_USER
) {
9726 ret
= perf_reg_validate(attr
->sample_regs_user
);
9731 if (attr
->sample_type
& PERF_SAMPLE_STACK_USER
) {
9732 if (!arch_perf_have_user_stack_dump())
9736 * We have __u32 type for the size, but so far
9737 * we can only use __u16 as maximum due to the
9738 * __u16 sample size limit.
9740 if (attr
->sample_stack_user
>= USHRT_MAX
)
9742 else if (!IS_ALIGNED(attr
->sample_stack_user
, sizeof(u64
)))
9746 if (attr
->sample_type
& PERF_SAMPLE_REGS_INTR
)
9747 ret
= perf_reg_validate(attr
->sample_regs_intr
);
9752 put_user(sizeof(*attr
), &uattr
->size
);
9758 perf_event_set_output(struct perf_event
*event
, struct perf_event
*output_event
)
9760 struct ring_buffer
*rb
= NULL
;
9766 /* don't allow circular references */
9767 if (event
== output_event
)
9771 * Don't allow cross-cpu buffers
9773 if (output_event
->cpu
!= event
->cpu
)
9777 * If its not a per-cpu rb, it must be the same task.
9779 if (output_event
->cpu
== -1 && output_event
->ctx
!= event
->ctx
)
9783 * Mixing clocks in the same buffer is trouble you don't need.
9785 if (output_event
->clock
!= event
->clock
)
9789 * Either writing ring buffer from beginning or from end.
9790 * Mixing is not allowed.
9792 if (is_write_backward(output_event
) != is_write_backward(event
))
9796 * If both events generate aux data, they must be on the same PMU
9798 if (has_aux(event
) && has_aux(output_event
) &&
9799 event
->pmu
!= output_event
->pmu
)
9803 mutex_lock(&event
->mmap_mutex
);
9804 /* Can't redirect output if we've got an active mmap() */
9805 if (atomic_read(&event
->mmap_count
))
9809 /* get the rb we want to redirect to */
9810 rb
= ring_buffer_get(output_event
);
9815 ring_buffer_attach(event
, rb
);
9819 mutex_unlock(&event
->mmap_mutex
);
9825 static void mutex_lock_double(struct mutex
*a
, struct mutex
*b
)
9831 mutex_lock_nested(b
, SINGLE_DEPTH_NESTING
);
9834 static int perf_event_set_clock(struct perf_event
*event
, clockid_t clk_id
)
9836 bool nmi_safe
= false;
9839 case CLOCK_MONOTONIC
:
9840 event
->clock
= &ktime_get_mono_fast_ns
;
9844 case CLOCK_MONOTONIC_RAW
:
9845 event
->clock
= &ktime_get_raw_fast_ns
;
9849 case CLOCK_REALTIME
:
9850 event
->clock
= &ktime_get_real_ns
;
9853 case CLOCK_BOOTTIME
:
9854 event
->clock
= &ktime_get_boot_ns
;
9858 event
->clock
= &ktime_get_tai_ns
;
9865 if (!nmi_safe
&& !(event
->pmu
->capabilities
& PERF_PMU_CAP_NO_NMI
))
9872 * Variation on perf_event_ctx_lock_nested(), except we take two context
9875 static struct perf_event_context
*
9876 __perf_event_ctx_lock_double(struct perf_event
*group_leader
,
9877 struct perf_event_context
*ctx
)
9879 struct perf_event_context
*gctx
;
9883 gctx
= READ_ONCE(group_leader
->ctx
);
9884 if (!atomic_inc_not_zero(&gctx
->refcount
)) {
9890 mutex_lock_double(&gctx
->mutex
, &ctx
->mutex
);
9892 if (group_leader
->ctx
!= gctx
) {
9893 mutex_unlock(&ctx
->mutex
);
9894 mutex_unlock(&gctx
->mutex
);
9903 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9905 * @attr_uptr: event_id type attributes for monitoring/sampling
9908 * @group_fd: group leader event fd
9910 SYSCALL_DEFINE5(perf_event_open
,
9911 struct perf_event_attr __user
*, attr_uptr
,
9912 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
9914 struct perf_event
*group_leader
= NULL
, *output_event
= NULL
;
9915 struct perf_event
*event
, *sibling
;
9916 struct perf_event_attr attr
;
9917 struct perf_event_context
*ctx
, *uninitialized_var(gctx
);
9918 struct file
*event_file
= NULL
;
9919 struct fd group
= {NULL
, 0};
9920 struct task_struct
*task
= NULL
;
9925 int f_flags
= O_RDWR
;
9928 /* for future expandability... */
9929 if (flags
& ~PERF_FLAG_ALL
)
9932 err
= perf_copy_attr(attr_uptr
, &attr
);
9936 if (!attr
.exclude_kernel
) {
9937 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
9941 if (attr
.namespaces
) {
9942 if (!capable(CAP_SYS_ADMIN
))
9947 if (attr
.sample_freq
> sysctl_perf_event_sample_rate
)
9950 if (attr
.sample_period
& (1ULL << 63))
9954 /* Only privileged users can get physical addresses */
9955 if ((attr
.sample_type
& PERF_SAMPLE_PHYS_ADDR
) &&
9956 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
9959 if (!attr
.sample_max_stack
)
9960 attr
.sample_max_stack
= sysctl_perf_event_max_stack
;
9963 * In cgroup mode, the pid argument is used to pass the fd
9964 * opened to the cgroup directory in cgroupfs. The cpu argument
9965 * designates the cpu on which to monitor threads from that
9968 if ((flags
& PERF_FLAG_PID_CGROUP
) && (pid
== -1 || cpu
== -1))
9971 if (flags
& PERF_FLAG_FD_CLOEXEC
)
9972 f_flags
|= O_CLOEXEC
;
9974 event_fd
= get_unused_fd_flags(f_flags
);
9978 if (group_fd
!= -1) {
9979 err
= perf_fget_light(group_fd
, &group
);
9982 group_leader
= group
.file
->private_data
;
9983 if (flags
& PERF_FLAG_FD_OUTPUT
)
9984 output_event
= group_leader
;
9985 if (flags
& PERF_FLAG_FD_NO_GROUP
)
9986 group_leader
= NULL
;
9989 if (pid
!= -1 && !(flags
& PERF_FLAG_PID_CGROUP
)) {
9990 task
= find_lively_task_by_vpid(pid
);
9992 err
= PTR_ERR(task
);
9997 if (task
&& group_leader
&&
9998 group_leader
->attr
.inherit
!= attr
.inherit
) {
10004 err
= mutex_lock_interruptible(&task
->signal
->cred_guard_mutex
);
10009 * Reuse ptrace permission checks for now.
10011 * We must hold cred_guard_mutex across this and any potential
10012 * perf_install_in_context() call for this new event to
10013 * serialize against exec() altering our credentials (and the
10014 * perf_event_exit_task() that could imply).
10017 if (!ptrace_may_access(task
, PTRACE_MODE_READ_REALCREDS
))
10021 if (flags
& PERF_FLAG_PID_CGROUP
)
10024 event
= perf_event_alloc(&attr
, cpu
, task
, group_leader
, NULL
,
10025 NULL
, NULL
, cgroup_fd
);
10026 if (IS_ERR(event
)) {
10027 err
= PTR_ERR(event
);
10031 if (is_sampling_event(event
)) {
10032 if (event
->pmu
->capabilities
& PERF_PMU_CAP_NO_INTERRUPT
) {
10039 * Special case software events and allow them to be part of
10040 * any hardware group.
10044 if (attr
.use_clockid
) {
10045 err
= perf_event_set_clock(event
, attr
.clockid
);
10050 if (pmu
->task_ctx_nr
== perf_sw_context
)
10051 event
->event_caps
|= PERF_EV_CAP_SOFTWARE
;
10053 if (group_leader
&&
10054 (is_software_event(event
) != is_software_event(group_leader
))) {
10055 if (is_software_event(event
)) {
10057 * If event and group_leader are not both a software
10058 * event, and event is, then group leader is not.
10060 * Allow the addition of software events to !software
10061 * groups, this is safe because software events never
10062 * fail to schedule.
10064 pmu
= group_leader
->pmu
;
10065 } else if (is_software_event(group_leader
) &&
10066 (group_leader
->group_caps
& PERF_EV_CAP_SOFTWARE
)) {
10068 * In case the group is a pure software group, and we
10069 * try to add a hardware event, move the whole group to
10070 * the hardware context.
10077 * Get the target context (task or percpu):
10079 ctx
= find_get_context(pmu
, task
, event
);
10081 err
= PTR_ERR(ctx
);
10085 if ((pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
) && group_leader
) {
10091 * Look up the group leader (we will attach this event to it):
10093 if (group_leader
) {
10097 * Do not allow a recursive hierarchy (this new sibling
10098 * becoming part of another group-sibling):
10100 if (group_leader
->group_leader
!= group_leader
)
10103 /* All events in a group should have the same clock */
10104 if (group_leader
->clock
!= event
->clock
)
10108 * Make sure we're both events for the same CPU;
10109 * grouping events for different CPUs is broken; since
10110 * you can never concurrently schedule them anyhow.
10112 if (group_leader
->cpu
!= event
->cpu
)
10116 * Make sure we're both on the same task, or both
10119 if (group_leader
->ctx
->task
!= ctx
->task
)
10123 * Do not allow to attach to a group in a different task
10124 * or CPU context. If we're moving SW events, we'll fix
10125 * this up later, so allow that.
10127 if (!move_group
&& group_leader
->ctx
!= ctx
)
10131 * Only a group leader can be exclusive or pinned
10133 if (attr
.exclusive
|| attr
.pinned
)
10137 if (output_event
) {
10138 err
= perf_event_set_output(event
, output_event
);
10143 event_file
= anon_inode_getfile("[perf_event]", &perf_fops
, event
,
10145 if (IS_ERR(event_file
)) {
10146 err
= PTR_ERR(event_file
);
10152 gctx
= __perf_event_ctx_lock_double(group_leader
, ctx
);
10154 if (gctx
->task
== TASK_TOMBSTONE
) {
10160 * Check if we raced against another sys_perf_event_open() call
10161 * moving the software group underneath us.
10163 if (!(group_leader
->group_caps
& PERF_EV_CAP_SOFTWARE
)) {
10165 * If someone moved the group out from under us, check
10166 * if this new event wound up on the same ctx, if so
10167 * its the regular !move_group case, otherwise fail.
10173 perf_event_ctx_unlock(group_leader
, gctx
);
10178 mutex_lock(&ctx
->mutex
);
10181 if (ctx
->task
== TASK_TOMBSTONE
) {
10186 if (!perf_event_validate_size(event
)) {
10193 * Check if the @cpu we're creating an event for is online.
10195 * We use the perf_cpu_context::ctx::mutex to serialize against
10196 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10198 struct perf_cpu_context
*cpuctx
=
10199 container_of(ctx
, struct perf_cpu_context
, ctx
);
10201 if (!cpuctx
->online
) {
10209 * Must be under the same ctx::mutex as perf_install_in_context(),
10210 * because we need to serialize with concurrent event creation.
10212 if (!exclusive_event_installable(event
, ctx
)) {
10213 /* exclusive and group stuff are assumed mutually exclusive */
10214 WARN_ON_ONCE(move_group
);
10220 WARN_ON_ONCE(ctx
->parent_ctx
);
10223 * This is the point on no return; we cannot fail hereafter. This is
10224 * where we start modifying current state.
10229 * See perf_event_ctx_lock() for comments on the details
10230 * of swizzling perf_event::ctx.
10232 perf_remove_from_context(group_leader
, 0);
10235 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
10237 perf_remove_from_context(sibling
, 0);
10242 * Wait for everybody to stop referencing the events through
10243 * the old lists, before installing it on new lists.
10248 * Install the group siblings before the group leader.
10250 * Because a group leader will try and install the entire group
10251 * (through the sibling list, which is still in-tact), we can
10252 * end up with siblings installed in the wrong context.
10254 * By installing siblings first we NO-OP because they're not
10255 * reachable through the group lists.
10257 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
10259 perf_event__state_init(sibling
);
10260 perf_install_in_context(ctx
, sibling
, sibling
->cpu
);
10265 * Removing from the context ends up with disabled
10266 * event. What we want here is event in the initial
10267 * startup state, ready to be add into new context.
10269 perf_event__state_init(group_leader
);
10270 perf_install_in_context(ctx
, group_leader
, group_leader
->cpu
);
10275 * Precalculate sample_data sizes; do while holding ctx::mutex such
10276 * that we're serialized against further additions and before
10277 * perf_install_in_context() which is the point the event is active and
10278 * can use these values.
10280 perf_event__header_size(event
);
10281 perf_event__id_header_size(event
);
10283 event
->owner
= current
;
10285 perf_install_in_context(ctx
, event
, event
->cpu
);
10286 perf_unpin_context(ctx
);
10289 perf_event_ctx_unlock(group_leader
, gctx
);
10290 mutex_unlock(&ctx
->mutex
);
10293 mutex_unlock(&task
->signal
->cred_guard_mutex
);
10294 put_task_struct(task
);
10297 mutex_lock(¤t
->perf_event_mutex
);
10298 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
10299 mutex_unlock(¤t
->perf_event_mutex
);
10302 * Drop the reference on the group_event after placing the
10303 * new event on the sibling_list. This ensures destruction
10304 * of the group leader will find the pointer to itself in
10305 * perf_group_detach().
10308 fd_install(event_fd
, event_file
);
10313 perf_event_ctx_unlock(group_leader
, gctx
);
10314 mutex_unlock(&ctx
->mutex
);
10318 perf_unpin_context(ctx
);
10322 * If event_file is set, the fput() above will have called ->release()
10323 * and that will take care of freeing the event.
10329 mutex_unlock(&task
->signal
->cred_guard_mutex
);
10332 put_task_struct(task
);
10336 put_unused_fd(event_fd
);
10341 * perf_event_create_kernel_counter
10343 * @attr: attributes of the counter to create
10344 * @cpu: cpu in which the counter is bound
10345 * @task: task to profile (NULL for percpu)
10347 struct perf_event
*
10348 perf_event_create_kernel_counter(struct perf_event_attr
*attr
, int cpu
,
10349 struct task_struct
*task
,
10350 perf_overflow_handler_t overflow_handler
,
10353 struct perf_event_context
*ctx
;
10354 struct perf_event
*event
;
10358 * Get the target context (task or percpu):
10361 event
= perf_event_alloc(attr
, cpu
, task
, NULL
, NULL
,
10362 overflow_handler
, context
, -1);
10363 if (IS_ERR(event
)) {
10364 err
= PTR_ERR(event
);
10368 /* Mark owner so we could distinguish it from user events. */
10369 event
->owner
= TASK_TOMBSTONE
;
10371 ctx
= find_get_context(event
->pmu
, task
, event
);
10373 err
= PTR_ERR(ctx
);
10377 WARN_ON_ONCE(ctx
->parent_ctx
);
10378 mutex_lock(&ctx
->mutex
);
10379 if (ctx
->task
== TASK_TOMBSTONE
) {
10386 * Check if the @cpu we're creating an event for is online.
10388 * We use the perf_cpu_context::ctx::mutex to serialize against
10389 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10391 struct perf_cpu_context
*cpuctx
=
10392 container_of(ctx
, struct perf_cpu_context
, ctx
);
10393 if (!cpuctx
->online
) {
10399 if (!exclusive_event_installable(event
, ctx
)) {
10404 perf_install_in_context(ctx
, event
, cpu
);
10405 perf_unpin_context(ctx
);
10406 mutex_unlock(&ctx
->mutex
);
10411 mutex_unlock(&ctx
->mutex
);
10412 perf_unpin_context(ctx
);
10417 return ERR_PTR(err
);
10419 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter
);
10421 void perf_pmu_migrate_context(struct pmu
*pmu
, int src_cpu
, int dst_cpu
)
10423 struct perf_event_context
*src_ctx
;
10424 struct perf_event_context
*dst_ctx
;
10425 struct perf_event
*event
, *tmp
;
10428 src_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, src_cpu
)->ctx
;
10429 dst_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, dst_cpu
)->ctx
;
10432 * See perf_event_ctx_lock() for comments on the details
10433 * of swizzling perf_event::ctx.
10435 mutex_lock_double(&src_ctx
->mutex
, &dst_ctx
->mutex
);
10436 list_for_each_entry_safe(event
, tmp
, &src_ctx
->event_list
,
10438 perf_remove_from_context(event
, 0);
10439 unaccount_event_cpu(event
, src_cpu
);
10441 list_add(&event
->migrate_entry
, &events
);
10445 * Wait for the events to quiesce before re-instating them.
10450 * Re-instate events in 2 passes.
10452 * Skip over group leaders and only install siblings on this first
10453 * pass, siblings will not get enabled without a leader, however a
10454 * leader will enable its siblings, even if those are still on the old
10457 list_for_each_entry_safe(event
, tmp
, &events
, migrate_entry
) {
10458 if (event
->group_leader
== event
)
10461 list_del(&event
->migrate_entry
);
10462 if (event
->state
>= PERF_EVENT_STATE_OFF
)
10463 event
->state
= PERF_EVENT_STATE_INACTIVE
;
10464 account_event_cpu(event
, dst_cpu
);
10465 perf_install_in_context(dst_ctx
, event
, dst_cpu
);
10470 * Once all the siblings are setup properly, install the group leaders
10473 list_for_each_entry_safe(event
, tmp
, &events
, migrate_entry
) {
10474 list_del(&event
->migrate_entry
);
10475 if (event
->state
>= PERF_EVENT_STATE_OFF
)
10476 event
->state
= PERF_EVENT_STATE_INACTIVE
;
10477 account_event_cpu(event
, dst_cpu
);
10478 perf_install_in_context(dst_ctx
, event
, dst_cpu
);
10481 mutex_unlock(&dst_ctx
->mutex
);
10482 mutex_unlock(&src_ctx
->mutex
);
10484 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context
);
10486 static void sync_child_event(struct perf_event
*child_event
,
10487 struct task_struct
*child
)
10489 struct perf_event
*parent_event
= child_event
->parent
;
10492 if (child_event
->attr
.inherit_stat
)
10493 perf_event_read_event(child_event
, child
);
10495 child_val
= perf_event_count(child_event
);
10498 * Add back the child's count to the parent's count:
10500 atomic64_add(child_val
, &parent_event
->child_count
);
10501 atomic64_add(child_event
->total_time_enabled
,
10502 &parent_event
->child_total_time_enabled
);
10503 atomic64_add(child_event
->total_time_running
,
10504 &parent_event
->child_total_time_running
);
10508 perf_event_exit_event(struct perf_event
*child_event
,
10509 struct perf_event_context
*child_ctx
,
10510 struct task_struct
*child
)
10512 struct perf_event
*parent_event
= child_event
->parent
;
10515 * Do not destroy the 'original' grouping; because of the context
10516 * switch optimization the original events could've ended up in a
10517 * random child task.
10519 * If we were to destroy the original group, all group related
10520 * operations would cease to function properly after this random
10523 * Do destroy all inherited groups, we don't care about those
10524 * and being thorough is better.
10526 raw_spin_lock_irq(&child_ctx
->lock
);
10527 WARN_ON_ONCE(child_ctx
->is_active
);
10530 perf_group_detach(child_event
);
10531 list_del_event(child_event
, child_ctx
);
10532 child_event
->state
= PERF_EVENT_STATE_EXIT
; /* is_event_hup() */
10533 raw_spin_unlock_irq(&child_ctx
->lock
);
10536 * Parent events are governed by their filedesc, retain them.
10538 if (!parent_event
) {
10539 perf_event_wakeup(child_event
);
10543 * Child events can be cleaned up.
10546 sync_child_event(child_event
, child
);
10549 * Remove this event from the parent's list
10551 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
10552 mutex_lock(&parent_event
->child_mutex
);
10553 list_del_init(&child_event
->child_list
);
10554 mutex_unlock(&parent_event
->child_mutex
);
10557 * Kick perf_poll() for is_event_hup().
10559 perf_event_wakeup(parent_event
);
10560 free_event(child_event
);
10561 put_event(parent_event
);
10564 static void perf_event_exit_task_context(struct task_struct
*child
, int ctxn
)
10566 struct perf_event_context
*child_ctx
, *clone_ctx
= NULL
;
10567 struct perf_event
*child_event
, *next
;
10569 WARN_ON_ONCE(child
!= current
);
10571 child_ctx
= perf_pin_task_context(child
, ctxn
);
10576 * In order to reduce the amount of tricky in ctx tear-down, we hold
10577 * ctx::mutex over the entire thing. This serializes against almost
10578 * everything that wants to access the ctx.
10580 * The exception is sys_perf_event_open() /
10581 * perf_event_create_kernel_count() which does find_get_context()
10582 * without ctx::mutex (it cannot because of the move_group double mutex
10583 * lock thing). See the comments in perf_install_in_context().
10585 mutex_lock(&child_ctx
->mutex
);
10588 * In a single ctx::lock section, de-schedule the events and detach the
10589 * context from the task such that we cannot ever get it scheduled back
10592 raw_spin_lock_irq(&child_ctx
->lock
);
10593 task_ctx_sched_out(__get_cpu_context(child_ctx
), child_ctx
, EVENT_ALL
);
10596 * Now that the context is inactive, destroy the task <-> ctx relation
10597 * and mark the context dead.
10599 RCU_INIT_POINTER(child
->perf_event_ctxp
[ctxn
], NULL
);
10600 put_ctx(child_ctx
); /* cannot be last */
10601 WRITE_ONCE(child_ctx
->task
, TASK_TOMBSTONE
);
10602 put_task_struct(current
); /* cannot be last */
10604 clone_ctx
= unclone_ctx(child_ctx
);
10605 raw_spin_unlock_irq(&child_ctx
->lock
);
10608 put_ctx(clone_ctx
);
10611 * Report the task dead after unscheduling the events so that we
10612 * won't get any samples after PERF_RECORD_EXIT. We can however still
10613 * get a few PERF_RECORD_READ events.
10615 perf_event_task(child
, child_ctx
, 0);
10617 list_for_each_entry_safe(child_event
, next
, &child_ctx
->event_list
, event_entry
)
10618 perf_event_exit_event(child_event
, child_ctx
, child
);
10620 mutex_unlock(&child_ctx
->mutex
);
10622 put_ctx(child_ctx
);
10626 * When a child task exits, feed back event values to parent events.
10628 * Can be called with cred_guard_mutex held when called from
10629 * install_exec_creds().
10631 void perf_event_exit_task(struct task_struct
*child
)
10633 struct perf_event
*event
, *tmp
;
10636 mutex_lock(&child
->perf_event_mutex
);
10637 list_for_each_entry_safe(event
, tmp
, &child
->perf_event_list
,
10639 list_del_init(&event
->owner_entry
);
10642 * Ensure the list deletion is visible before we clear
10643 * the owner, closes a race against perf_release() where
10644 * we need to serialize on the owner->perf_event_mutex.
10646 smp_store_release(&event
->owner
, NULL
);
10648 mutex_unlock(&child
->perf_event_mutex
);
10650 for_each_task_context_nr(ctxn
)
10651 perf_event_exit_task_context(child
, ctxn
);
10654 * The perf_event_exit_task_context calls perf_event_task
10655 * with child's task_ctx, which generates EXIT events for
10656 * child contexts and sets child->perf_event_ctxp[] to NULL.
10657 * At this point we need to send EXIT events to cpu contexts.
10659 perf_event_task(child
, NULL
, 0);
10662 static void perf_free_event(struct perf_event
*event
,
10663 struct perf_event_context
*ctx
)
10665 struct perf_event
*parent
= event
->parent
;
10667 if (WARN_ON_ONCE(!parent
))
10670 mutex_lock(&parent
->child_mutex
);
10671 list_del_init(&event
->child_list
);
10672 mutex_unlock(&parent
->child_mutex
);
10676 raw_spin_lock_irq(&ctx
->lock
);
10677 perf_group_detach(event
);
10678 list_del_event(event
, ctx
);
10679 raw_spin_unlock_irq(&ctx
->lock
);
10684 * Free an unexposed, unused context as created by inheritance by
10685 * perf_event_init_task below, used by fork() in case of fail.
10687 * Not all locks are strictly required, but take them anyway to be nice and
10688 * help out with the lockdep assertions.
10690 void perf_event_free_task(struct task_struct
*task
)
10692 struct perf_event_context
*ctx
;
10693 struct perf_event
*event
, *tmp
;
10696 for_each_task_context_nr(ctxn
) {
10697 ctx
= task
->perf_event_ctxp
[ctxn
];
10701 mutex_lock(&ctx
->mutex
);
10702 raw_spin_lock_irq(&ctx
->lock
);
10704 * Destroy the task <-> ctx relation and mark the context dead.
10706 * This is important because even though the task hasn't been
10707 * exposed yet the context has been (through child_list).
10709 RCU_INIT_POINTER(task
->perf_event_ctxp
[ctxn
], NULL
);
10710 WRITE_ONCE(ctx
->task
, TASK_TOMBSTONE
);
10711 put_task_struct(task
); /* cannot be last */
10712 raw_spin_unlock_irq(&ctx
->lock
);
10714 list_for_each_entry_safe(event
, tmp
, &ctx
->event_list
, event_entry
)
10715 perf_free_event(event
, ctx
);
10717 mutex_unlock(&ctx
->mutex
);
10722 void perf_event_delayed_put(struct task_struct
*task
)
10726 for_each_task_context_nr(ctxn
)
10727 WARN_ON_ONCE(task
->perf_event_ctxp
[ctxn
]);
10730 struct file
*perf_event_get(unsigned int fd
)
10734 file
= fget_raw(fd
);
10736 return ERR_PTR(-EBADF
);
10738 if (file
->f_op
!= &perf_fops
) {
10740 return ERR_PTR(-EBADF
);
10746 const struct perf_event_attr
*perf_event_attrs(struct perf_event
*event
)
10749 return ERR_PTR(-EINVAL
);
10751 return &event
->attr
;
10755 * Inherit a event from parent task to child task.
10758 * - valid pointer on success
10759 * - NULL for orphaned events
10760 * - IS_ERR() on error
10762 static struct perf_event
*
10763 inherit_event(struct perf_event
*parent_event
,
10764 struct task_struct
*parent
,
10765 struct perf_event_context
*parent_ctx
,
10766 struct task_struct
*child
,
10767 struct perf_event
*group_leader
,
10768 struct perf_event_context
*child_ctx
)
10770 enum perf_event_active_state parent_state
= parent_event
->state
;
10771 struct perf_event
*child_event
;
10772 unsigned long flags
;
10775 * Instead of creating recursive hierarchies of events,
10776 * we link inherited events back to the original parent,
10777 * which has a filp for sure, which we use as the reference
10780 if (parent_event
->parent
)
10781 parent_event
= parent_event
->parent
;
10783 child_event
= perf_event_alloc(&parent_event
->attr
,
10786 group_leader
, parent_event
,
10788 if (IS_ERR(child_event
))
10789 return child_event
;
10792 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10793 * must be under the same lock in order to serialize against
10794 * perf_event_release_kernel(), such that either we must observe
10795 * is_orphaned_event() or they will observe us on the child_list.
10797 mutex_lock(&parent_event
->child_mutex
);
10798 if (is_orphaned_event(parent_event
) ||
10799 !atomic_long_inc_not_zero(&parent_event
->refcount
)) {
10800 mutex_unlock(&parent_event
->child_mutex
);
10801 free_event(child_event
);
10805 get_ctx(child_ctx
);
10808 * Make the child state follow the state of the parent event,
10809 * not its attr.disabled bit. We hold the parent's mutex,
10810 * so we won't race with perf_event_{en, dis}able_family.
10812 if (parent_state
>= PERF_EVENT_STATE_INACTIVE
)
10813 child_event
->state
= PERF_EVENT_STATE_INACTIVE
;
10815 child_event
->state
= PERF_EVENT_STATE_OFF
;
10817 if (parent_event
->attr
.freq
) {
10818 u64 sample_period
= parent_event
->hw
.sample_period
;
10819 struct hw_perf_event
*hwc
= &child_event
->hw
;
10821 hwc
->sample_period
= sample_period
;
10822 hwc
->last_period
= sample_period
;
10824 local64_set(&hwc
->period_left
, sample_period
);
10827 child_event
->ctx
= child_ctx
;
10828 child_event
->overflow_handler
= parent_event
->overflow_handler
;
10829 child_event
->overflow_handler_context
10830 = parent_event
->overflow_handler_context
;
10833 * Precalculate sample_data sizes
10835 perf_event__header_size(child_event
);
10836 perf_event__id_header_size(child_event
);
10839 * Link it up in the child's context:
10841 raw_spin_lock_irqsave(&child_ctx
->lock
, flags
);
10842 add_event_to_ctx(child_event
, child_ctx
);
10843 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
10846 * Link this into the parent event's child list
10848 list_add_tail(&child_event
->child_list
, &parent_event
->child_list
);
10849 mutex_unlock(&parent_event
->child_mutex
);
10851 return child_event
;
10855 * Inherits an event group.
10857 * This will quietly suppress orphaned events; !inherit_event() is not an error.
10858 * This matches with perf_event_release_kernel() removing all child events.
10864 static int inherit_group(struct perf_event
*parent_event
,
10865 struct task_struct
*parent
,
10866 struct perf_event_context
*parent_ctx
,
10867 struct task_struct
*child
,
10868 struct perf_event_context
*child_ctx
)
10870 struct perf_event
*leader
;
10871 struct perf_event
*sub
;
10872 struct perf_event
*child_ctr
;
10874 leader
= inherit_event(parent_event
, parent
, parent_ctx
,
10875 child
, NULL
, child_ctx
);
10876 if (IS_ERR(leader
))
10877 return PTR_ERR(leader
);
10879 * @leader can be NULL here because of is_orphaned_event(). In this
10880 * case inherit_event() will create individual events, similar to what
10881 * perf_group_detach() would do anyway.
10883 list_for_each_entry(sub
, &parent_event
->sibling_list
, group_entry
) {
10884 child_ctr
= inherit_event(sub
, parent
, parent_ctx
,
10885 child
, leader
, child_ctx
);
10886 if (IS_ERR(child_ctr
))
10887 return PTR_ERR(child_ctr
);
10893 * Creates the child task context and tries to inherit the event-group.
10895 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
10896 * inherited_all set when we 'fail' to inherit an orphaned event; this is
10897 * consistent with perf_event_release_kernel() removing all child events.
10904 inherit_task_group(struct perf_event
*event
, struct task_struct
*parent
,
10905 struct perf_event_context
*parent_ctx
,
10906 struct task_struct
*child
, int ctxn
,
10907 int *inherited_all
)
10910 struct perf_event_context
*child_ctx
;
10912 if (!event
->attr
.inherit
) {
10913 *inherited_all
= 0;
10917 child_ctx
= child
->perf_event_ctxp
[ctxn
];
10920 * This is executed from the parent task context, so
10921 * inherit events that have been marked for cloning.
10922 * First allocate and initialize a context for the
10925 child_ctx
= alloc_perf_context(parent_ctx
->pmu
, child
);
10929 child
->perf_event_ctxp
[ctxn
] = child_ctx
;
10932 ret
= inherit_group(event
, parent
, parent_ctx
,
10936 *inherited_all
= 0;
10942 * Initialize the perf_event context in task_struct
10944 static int perf_event_init_context(struct task_struct
*child
, int ctxn
)
10946 struct perf_event_context
*child_ctx
, *parent_ctx
;
10947 struct perf_event_context
*cloned_ctx
;
10948 struct perf_event
*event
;
10949 struct task_struct
*parent
= current
;
10950 int inherited_all
= 1;
10951 unsigned long flags
;
10954 if (likely(!parent
->perf_event_ctxp
[ctxn
]))
10958 * If the parent's context is a clone, pin it so it won't get
10959 * swapped under us.
10961 parent_ctx
= perf_pin_task_context(parent
, ctxn
);
10966 * No need to check if parent_ctx != NULL here; since we saw
10967 * it non-NULL earlier, the only reason for it to become NULL
10968 * is if we exit, and since we're currently in the middle of
10969 * a fork we can't be exiting at the same time.
10973 * Lock the parent list. No need to lock the child - not PID
10974 * hashed yet and not running, so nobody can access it.
10976 mutex_lock(&parent_ctx
->mutex
);
10979 * We dont have to disable NMIs - we are only looking at
10980 * the list, not manipulating it:
10982 list_for_each_entry(event
, &parent_ctx
->pinned_groups
, group_entry
) {
10983 ret
= inherit_task_group(event
, parent
, parent_ctx
,
10984 child
, ctxn
, &inherited_all
);
10990 * We can't hold ctx->lock when iterating the ->flexible_group list due
10991 * to allocations, but we need to prevent rotation because
10992 * rotate_ctx() will change the list from interrupt context.
10994 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
10995 parent_ctx
->rotate_disable
= 1;
10996 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
10998 list_for_each_entry(event
, &parent_ctx
->flexible_groups
, group_entry
) {
10999 ret
= inherit_task_group(event
, parent
, parent_ctx
,
11000 child
, ctxn
, &inherited_all
);
11005 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
11006 parent_ctx
->rotate_disable
= 0;
11008 child_ctx
= child
->perf_event_ctxp
[ctxn
];
11010 if (child_ctx
&& inherited_all
) {
11012 * Mark the child context as a clone of the parent
11013 * context, or of whatever the parent is a clone of.
11015 * Note that if the parent is a clone, the holding of
11016 * parent_ctx->lock avoids it from being uncloned.
11018 cloned_ctx
= parent_ctx
->parent_ctx
;
11020 child_ctx
->parent_ctx
= cloned_ctx
;
11021 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
11023 child_ctx
->parent_ctx
= parent_ctx
;
11024 child_ctx
->parent_gen
= parent_ctx
->generation
;
11026 get_ctx(child_ctx
->parent_ctx
);
11029 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
11031 mutex_unlock(&parent_ctx
->mutex
);
11033 perf_unpin_context(parent_ctx
);
11034 put_ctx(parent_ctx
);
11040 * Initialize the perf_event context in task_struct
11042 int perf_event_init_task(struct task_struct
*child
)
11046 memset(child
->perf_event_ctxp
, 0, sizeof(child
->perf_event_ctxp
));
11047 mutex_init(&child
->perf_event_mutex
);
11048 INIT_LIST_HEAD(&child
->perf_event_list
);
11050 for_each_task_context_nr(ctxn
) {
11051 ret
= perf_event_init_context(child
, ctxn
);
11053 perf_event_free_task(child
);
11061 static void __init
perf_event_init_all_cpus(void)
11063 struct swevent_htable
*swhash
;
11066 zalloc_cpumask_var(&perf_online_mask
, GFP_KERNEL
);
11068 for_each_possible_cpu(cpu
) {
11069 swhash
= &per_cpu(swevent_htable
, cpu
);
11070 mutex_init(&swhash
->hlist_mutex
);
11071 INIT_LIST_HEAD(&per_cpu(active_ctx_list
, cpu
));
11073 INIT_LIST_HEAD(&per_cpu(pmu_sb_events
.list
, cpu
));
11074 raw_spin_lock_init(&per_cpu(pmu_sb_events
.lock
, cpu
));
11076 #ifdef CONFIG_CGROUP_PERF
11077 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list
, cpu
));
11079 INIT_LIST_HEAD(&per_cpu(sched_cb_list
, cpu
));
11083 void perf_swevent_init_cpu(unsigned int cpu
)
11085 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
11087 mutex_lock(&swhash
->hlist_mutex
);
11088 if (swhash
->hlist_refcount
> 0 && !swevent_hlist_deref(swhash
)) {
11089 struct swevent_hlist
*hlist
;
11091 hlist
= kzalloc_node(sizeof(*hlist
), GFP_KERNEL
, cpu_to_node(cpu
));
11093 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
11095 mutex_unlock(&swhash
->hlist_mutex
);
11098 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11099 static void __perf_event_exit_context(void *__info
)
11101 struct perf_event_context
*ctx
= __info
;
11102 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
11103 struct perf_event
*event
;
11105 raw_spin_lock(&ctx
->lock
);
11106 list_for_each_entry(event
, &ctx
->event_list
, event_entry
)
11107 __perf_remove_from_context(event
, cpuctx
, ctx
, (void *)DETACH_GROUP
);
11108 raw_spin_unlock(&ctx
->lock
);
11111 static void perf_event_exit_cpu_context(int cpu
)
11113 struct perf_cpu_context
*cpuctx
;
11114 struct perf_event_context
*ctx
;
11117 mutex_lock(&pmus_lock
);
11118 list_for_each_entry(pmu
, &pmus
, entry
) {
11119 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
11120 ctx
= &cpuctx
->ctx
;
11122 mutex_lock(&ctx
->mutex
);
11123 smp_call_function_single(cpu
, __perf_event_exit_context
, ctx
, 1);
11124 cpuctx
->online
= 0;
11125 mutex_unlock(&ctx
->mutex
);
11127 cpumask_clear_cpu(cpu
, perf_online_mask
);
11128 mutex_unlock(&pmus_lock
);
11132 static void perf_event_exit_cpu_context(int cpu
) { }
11136 int perf_event_init_cpu(unsigned int cpu
)
11138 struct perf_cpu_context
*cpuctx
;
11139 struct perf_event_context
*ctx
;
11142 perf_swevent_init_cpu(cpu
);
11144 mutex_lock(&pmus_lock
);
11145 cpumask_set_cpu(cpu
, perf_online_mask
);
11146 list_for_each_entry(pmu
, &pmus
, entry
) {
11147 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
11148 ctx
= &cpuctx
->ctx
;
11150 mutex_lock(&ctx
->mutex
);
11151 cpuctx
->online
= 1;
11152 mutex_unlock(&ctx
->mutex
);
11154 mutex_unlock(&pmus_lock
);
11159 int perf_event_exit_cpu(unsigned int cpu
)
11161 perf_event_exit_cpu_context(cpu
);
11166 perf_reboot(struct notifier_block
*notifier
, unsigned long val
, void *v
)
11170 for_each_online_cpu(cpu
)
11171 perf_event_exit_cpu(cpu
);
11177 * Run the perf reboot notifier at the very last possible moment so that
11178 * the generic watchdog code runs as long as possible.
11180 static struct notifier_block perf_reboot_notifier
= {
11181 .notifier_call
= perf_reboot
,
11182 .priority
= INT_MIN
,
11185 void __init
perf_event_init(void)
11189 idr_init(&pmu_idr
);
11191 perf_event_init_all_cpus();
11192 init_srcu_struct(&pmus_srcu
);
11193 perf_pmu_register(&perf_swevent
, "software", PERF_TYPE_SOFTWARE
);
11194 perf_pmu_register(&perf_cpu_clock
, NULL
, -1);
11195 perf_pmu_register(&perf_task_clock
, NULL
, -1);
11196 perf_tp_register();
11197 perf_event_init_cpu(smp_processor_id());
11198 register_reboot_notifier(&perf_reboot_notifier
);
11200 ret
= init_hw_breakpoint();
11201 WARN(ret
, "hw_breakpoint initialization failed with: %d", ret
);
11204 * Build time assertion that we keep the data_head at the intended
11205 * location. IOW, validation we got the __reserved[] size right.
11207 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page
, data_head
))
11211 ssize_t
perf_event_sysfs_show(struct device
*dev
, struct device_attribute
*attr
,
11214 struct perf_pmu_events_attr
*pmu_attr
=
11215 container_of(attr
, struct perf_pmu_events_attr
, attr
);
11217 if (pmu_attr
->event_str
)
11218 return sprintf(page
, "%s\n", pmu_attr
->event_str
);
11222 EXPORT_SYMBOL_GPL(perf_event_sysfs_show
);
11224 static int __init
perf_event_sysfs_init(void)
11229 mutex_lock(&pmus_lock
);
11231 ret
= bus_register(&pmu_bus
);
11235 list_for_each_entry(pmu
, &pmus
, entry
) {
11236 if (!pmu
->name
|| pmu
->type
< 0)
11239 ret
= pmu_dev_alloc(pmu
);
11240 WARN(ret
, "Failed to register pmu: %s, reason %d\n", pmu
->name
, ret
);
11242 pmu_bus_running
= 1;
11246 mutex_unlock(&pmus_lock
);
11250 device_initcall(perf_event_sysfs_init
);
11252 #ifdef CONFIG_CGROUP_PERF
11253 static struct cgroup_subsys_state
*
11254 perf_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
11256 struct perf_cgroup
*jc
;
11258 jc
= kzalloc(sizeof(*jc
), GFP_KERNEL
);
11260 return ERR_PTR(-ENOMEM
);
11262 jc
->info
= alloc_percpu(struct perf_cgroup_info
);
11265 return ERR_PTR(-ENOMEM
);
11271 static void perf_cgroup_css_free(struct cgroup_subsys_state
*css
)
11273 struct perf_cgroup
*jc
= container_of(css
, struct perf_cgroup
, css
);
11275 free_percpu(jc
->info
);
11279 static int __perf_cgroup_move(void *info
)
11281 struct task_struct
*task
= info
;
11283 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
| PERF_CGROUP_SWIN
);
11288 static void perf_cgroup_attach(struct cgroup_taskset
*tset
)
11290 struct task_struct
*task
;
11291 struct cgroup_subsys_state
*css
;
11293 cgroup_taskset_for_each(task
, css
, tset
)
11294 task_function_call(task
, __perf_cgroup_move
, task
);
11297 struct cgroup_subsys perf_event_cgrp_subsys
= {
11298 .css_alloc
= perf_cgroup_css_alloc
,
11299 .css_free
= perf_cgroup_css_free
,
11300 .attach
= perf_cgroup_attach
,
11302 * Implicitly enable on dfl hierarchy so that perf events can
11303 * always be filtered by cgroup2 path as long as perf_event
11304 * controller is not mounted on a legacy hierarchy.
11306 .implicit_on_dfl
= true,
11309 #endif /* CONFIG_CGROUP_PERF */