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 (cgrp
== event
->cgrp
)
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 list_add(cpuctx_entry
, this_cpu_ptr(&cgrp_cpuctx_list
));
905 if (perf_cgroup_from_task(current
, ctx
) == event
->cgrp
)
906 cpuctx
->cgrp
= event
->cgrp
;
908 list_del(cpuctx_entry
);
913 #else /* !CONFIG_CGROUP_PERF */
916 perf_cgroup_match(struct perf_event
*event
)
921 static inline void perf_detach_cgroup(struct perf_event
*event
)
924 static inline int is_cgroup_event(struct perf_event
*event
)
929 static inline void update_cgrp_time_from_event(struct perf_event
*event
)
933 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context
*cpuctx
)
937 static inline void perf_cgroup_sched_out(struct task_struct
*task
,
938 struct task_struct
*next
)
942 static inline void perf_cgroup_sched_in(struct task_struct
*prev
,
943 struct task_struct
*task
)
947 static inline int perf_cgroup_connect(pid_t pid
, struct perf_event
*event
,
948 struct perf_event_attr
*attr
,
949 struct perf_event
*group_leader
)
955 perf_cgroup_set_timestamp(struct task_struct
*task
,
956 struct perf_event_context
*ctx
)
961 perf_cgroup_switch(struct task_struct
*task
, struct task_struct
*next
)
966 perf_cgroup_set_shadow_time(struct perf_event
*event
, u64 now
)
970 static inline u64
perf_cgroup_event_time(struct perf_event
*event
)
976 perf_cgroup_defer_enabled(struct perf_event
*event
)
981 perf_cgroup_mark_enabled(struct perf_event
*event
,
982 struct perf_event_context
*ctx
)
987 list_update_cgroup_event(struct perf_event
*event
,
988 struct perf_event_context
*ctx
, bool add
)
995 * set default to be dependent on timer tick just
998 #define PERF_CPU_HRTIMER (1000 / HZ)
1000 * function must be called with interrupts disabled
1002 static enum hrtimer_restart
perf_mux_hrtimer_handler(struct hrtimer
*hr
)
1004 struct perf_cpu_context
*cpuctx
;
1007 WARN_ON(!irqs_disabled());
1009 cpuctx
= container_of(hr
, struct perf_cpu_context
, hrtimer
);
1010 rotations
= perf_rotate_context(cpuctx
);
1012 raw_spin_lock(&cpuctx
->hrtimer_lock
);
1014 hrtimer_forward_now(hr
, cpuctx
->hrtimer_interval
);
1016 cpuctx
->hrtimer_active
= 0;
1017 raw_spin_unlock(&cpuctx
->hrtimer_lock
);
1019 return rotations
? HRTIMER_RESTART
: HRTIMER_NORESTART
;
1022 static void __perf_mux_hrtimer_init(struct perf_cpu_context
*cpuctx
, int cpu
)
1024 struct hrtimer
*timer
= &cpuctx
->hrtimer
;
1025 struct pmu
*pmu
= cpuctx
->ctx
.pmu
;
1028 /* no multiplexing needed for SW PMU */
1029 if (pmu
->task_ctx_nr
== perf_sw_context
)
1033 * check default is sane, if not set then force to
1034 * default interval (1/tick)
1036 interval
= pmu
->hrtimer_interval_ms
;
1038 interval
= pmu
->hrtimer_interval_ms
= PERF_CPU_HRTIMER
;
1040 cpuctx
->hrtimer_interval
= ns_to_ktime(NSEC_PER_MSEC
* interval
);
1042 raw_spin_lock_init(&cpuctx
->hrtimer_lock
);
1043 hrtimer_init(timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_ABS_PINNED
);
1044 timer
->function
= perf_mux_hrtimer_handler
;
1047 static int perf_mux_hrtimer_restart(struct perf_cpu_context
*cpuctx
)
1049 struct hrtimer
*timer
= &cpuctx
->hrtimer
;
1050 struct pmu
*pmu
= cpuctx
->ctx
.pmu
;
1051 unsigned long flags
;
1053 /* not for SW PMU */
1054 if (pmu
->task_ctx_nr
== perf_sw_context
)
1057 raw_spin_lock_irqsave(&cpuctx
->hrtimer_lock
, flags
);
1058 if (!cpuctx
->hrtimer_active
) {
1059 cpuctx
->hrtimer_active
= 1;
1060 hrtimer_forward_now(timer
, cpuctx
->hrtimer_interval
);
1061 hrtimer_start_expires(timer
, HRTIMER_MODE_ABS_PINNED
);
1063 raw_spin_unlock_irqrestore(&cpuctx
->hrtimer_lock
, flags
);
1068 void perf_pmu_disable(struct pmu
*pmu
)
1070 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
1072 pmu
->pmu_disable(pmu
);
1075 void perf_pmu_enable(struct pmu
*pmu
)
1077 int *count
= this_cpu_ptr(pmu
->pmu_disable_count
);
1079 pmu
->pmu_enable(pmu
);
1082 static DEFINE_PER_CPU(struct list_head
, active_ctx_list
);
1085 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1086 * perf_event_task_tick() are fully serialized because they're strictly cpu
1087 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1088 * disabled, while perf_event_task_tick is called from IRQ context.
1090 static void perf_event_ctx_activate(struct perf_event_context
*ctx
)
1092 struct list_head
*head
= this_cpu_ptr(&active_ctx_list
);
1094 WARN_ON(!irqs_disabled());
1096 WARN_ON(!list_empty(&ctx
->active_ctx_list
));
1098 list_add(&ctx
->active_ctx_list
, head
);
1101 static void perf_event_ctx_deactivate(struct perf_event_context
*ctx
)
1103 WARN_ON(!irqs_disabled());
1105 WARN_ON(list_empty(&ctx
->active_ctx_list
));
1107 list_del_init(&ctx
->active_ctx_list
);
1110 static void get_ctx(struct perf_event_context
*ctx
)
1112 WARN_ON(!atomic_inc_not_zero(&ctx
->refcount
));
1115 static void free_ctx(struct rcu_head
*head
)
1117 struct perf_event_context
*ctx
;
1119 ctx
= container_of(head
, struct perf_event_context
, rcu_head
);
1120 kfree(ctx
->task_ctx_data
);
1124 static void put_ctx(struct perf_event_context
*ctx
)
1126 if (atomic_dec_and_test(&ctx
->refcount
)) {
1127 if (ctx
->parent_ctx
)
1128 put_ctx(ctx
->parent_ctx
);
1129 if (ctx
->task
&& ctx
->task
!= TASK_TOMBSTONE
)
1130 put_task_struct(ctx
->task
);
1131 call_rcu(&ctx
->rcu_head
, free_ctx
);
1136 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1137 * perf_pmu_migrate_context() we need some magic.
1139 * Those places that change perf_event::ctx will hold both
1140 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1142 * Lock ordering is by mutex address. There are two other sites where
1143 * perf_event_context::mutex nests and those are:
1145 * - perf_event_exit_task_context() [ child , 0 ]
1146 * perf_event_exit_event()
1147 * put_event() [ parent, 1 ]
1149 * - perf_event_init_context() [ parent, 0 ]
1150 * inherit_task_group()
1153 * perf_event_alloc()
1155 * perf_try_init_event() [ child , 1 ]
1157 * While it appears there is an obvious deadlock here -- the parent and child
1158 * nesting levels are inverted between the two. This is in fact safe because
1159 * life-time rules separate them. That is an exiting task cannot fork, and a
1160 * spawning task cannot (yet) exit.
1162 * But remember that that these are parent<->child context relations, and
1163 * migration does not affect children, therefore these two orderings should not
1166 * The change in perf_event::ctx does not affect children (as claimed above)
1167 * because the sys_perf_event_open() case will install a new event and break
1168 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1169 * concerned with cpuctx and that doesn't have children.
1171 * The places that change perf_event::ctx will issue:
1173 * perf_remove_from_context();
1174 * synchronize_rcu();
1175 * perf_install_in_context();
1177 * to affect the change. The remove_from_context() + synchronize_rcu() should
1178 * quiesce the event, after which we can install it in the new location. This
1179 * means that only external vectors (perf_fops, prctl) can perturb the event
1180 * while in transit. Therefore all such accessors should also acquire
1181 * perf_event_context::mutex to serialize against this.
1183 * However; because event->ctx can change while we're waiting to acquire
1184 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1189 * task_struct::perf_event_mutex
1190 * perf_event_context::mutex
1191 * perf_event::child_mutex;
1192 * perf_event_context::lock
1193 * perf_event::mmap_mutex
1196 static struct perf_event_context
*
1197 perf_event_ctx_lock_nested(struct perf_event
*event
, int nesting
)
1199 struct perf_event_context
*ctx
;
1203 ctx
= ACCESS_ONCE(event
->ctx
);
1204 if (!atomic_inc_not_zero(&ctx
->refcount
)) {
1210 mutex_lock_nested(&ctx
->mutex
, nesting
);
1211 if (event
->ctx
!= ctx
) {
1212 mutex_unlock(&ctx
->mutex
);
1220 static inline struct perf_event_context
*
1221 perf_event_ctx_lock(struct perf_event
*event
)
1223 return perf_event_ctx_lock_nested(event
, 0);
1226 static void perf_event_ctx_unlock(struct perf_event
*event
,
1227 struct perf_event_context
*ctx
)
1229 mutex_unlock(&ctx
->mutex
);
1234 * This must be done under the ctx->lock, such as to serialize against
1235 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1236 * calling scheduler related locks and ctx->lock nests inside those.
1238 static __must_check
struct perf_event_context
*
1239 unclone_ctx(struct perf_event_context
*ctx
)
1241 struct perf_event_context
*parent_ctx
= ctx
->parent_ctx
;
1243 lockdep_assert_held(&ctx
->lock
);
1246 ctx
->parent_ctx
= NULL
;
1252 static u32
perf_event_pid(struct perf_event
*event
, struct task_struct
*p
)
1255 * only top level events have the pid namespace they were created in
1258 event
= event
->parent
;
1260 return task_tgid_nr_ns(p
, event
->ns
);
1263 static u32
perf_event_tid(struct perf_event
*event
, struct task_struct
*p
)
1266 * only top level events have the pid namespace they were created in
1269 event
= event
->parent
;
1271 return task_pid_nr_ns(p
, event
->ns
);
1275 * If we inherit events we want to return the parent event id
1278 static u64
primary_event_id(struct perf_event
*event
)
1283 id
= event
->parent
->id
;
1289 * Get the perf_event_context for a task and lock it.
1291 * This has to cope with with the fact that until it is locked,
1292 * the context could get moved to another task.
1294 static struct perf_event_context
*
1295 perf_lock_task_context(struct task_struct
*task
, int ctxn
, unsigned long *flags
)
1297 struct perf_event_context
*ctx
;
1301 * One of the few rules of preemptible RCU is that one cannot do
1302 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1303 * part of the read side critical section was irqs-enabled -- see
1304 * rcu_read_unlock_special().
1306 * Since ctx->lock nests under rq->lock we must ensure the entire read
1307 * side critical section has interrupts disabled.
1309 local_irq_save(*flags
);
1311 ctx
= rcu_dereference(task
->perf_event_ctxp
[ctxn
]);
1314 * If this context is a clone of another, it might
1315 * get swapped for another underneath us by
1316 * perf_event_task_sched_out, though the
1317 * rcu_read_lock() protects us from any context
1318 * getting freed. Lock the context and check if it
1319 * got swapped before we could get the lock, and retry
1320 * if so. If we locked the right context, then it
1321 * can't get swapped on us any more.
1323 raw_spin_lock(&ctx
->lock
);
1324 if (ctx
!= rcu_dereference(task
->perf_event_ctxp
[ctxn
])) {
1325 raw_spin_unlock(&ctx
->lock
);
1327 local_irq_restore(*flags
);
1331 if (ctx
->task
== TASK_TOMBSTONE
||
1332 !atomic_inc_not_zero(&ctx
->refcount
)) {
1333 raw_spin_unlock(&ctx
->lock
);
1336 WARN_ON_ONCE(ctx
->task
!= task
);
1341 local_irq_restore(*flags
);
1346 * Get the context for a task and increment its pin_count so it
1347 * can't get swapped to another task. This also increments its
1348 * reference count so that the context can't get freed.
1350 static struct perf_event_context
*
1351 perf_pin_task_context(struct task_struct
*task
, int ctxn
)
1353 struct perf_event_context
*ctx
;
1354 unsigned long flags
;
1356 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
1359 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1364 static void perf_unpin_context(struct perf_event_context
*ctx
)
1366 unsigned long flags
;
1368 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
1370 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1374 * Update the record of the current time in a context.
1376 static void update_context_time(struct perf_event_context
*ctx
)
1378 u64 now
= perf_clock();
1380 ctx
->time
+= now
- ctx
->timestamp
;
1381 ctx
->timestamp
= now
;
1384 static u64
perf_event_time(struct perf_event
*event
)
1386 struct perf_event_context
*ctx
= event
->ctx
;
1388 if (is_cgroup_event(event
))
1389 return perf_cgroup_event_time(event
);
1391 return ctx
? ctx
->time
: 0;
1395 * Update the total_time_enabled and total_time_running fields for a event.
1397 static void update_event_times(struct perf_event
*event
)
1399 struct perf_event_context
*ctx
= event
->ctx
;
1402 lockdep_assert_held(&ctx
->lock
);
1404 if (event
->state
< PERF_EVENT_STATE_INACTIVE
||
1405 event
->group_leader
->state
< PERF_EVENT_STATE_INACTIVE
)
1409 * in cgroup mode, time_enabled represents
1410 * the time the event was enabled AND active
1411 * tasks were in the monitored cgroup. This is
1412 * independent of the activity of the context as
1413 * there may be a mix of cgroup and non-cgroup events.
1415 * That is why we treat cgroup events differently
1418 if (is_cgroup_event(event
))
1419 run_end
= perf_cgroup_event_time(event
);
1420 else if (ctx
->is_active
)
1421 run_end
= ctx
->time
;
1423 run_end
= event
->tstamp_stopped
;
1425 event
->total_time_enabled
= run_end
- event
->tstamp_enabled
;
1427 if (event
->state
== PERF_EVENT_STATE_INACTIVE
)
1428 run_end
= event
->tstamp_stopped
;
1430 run_end
= perf_event_time(event
);
1432 event
->total_time_running
= run_end
- event
->tstamp_running
;
1437 * Update total_time_enabled and total_time_running for all events in a group.
1439 static void update_group_times(struct perf_event
*leader
)
1441 struct perf_event
*event
;
1443 update_event_times(leader
);
1444 list_for_each_entry(event
, &leader
->sibling_list
, group_entry
)
1445 update_event_times(event
);
1448 static enum event_type_t
get_event_type(struct perf_event
*event
)
1450 struct perf_event_context
*ctx
= event
->ctx
;
1451 enum event_type_t event_type
;
1453 lockdep_assert_held(&ctx
->lock
);
1456 * It's 'group type', really, because if our group leader is
1457 * pinned, so are we.
1459 if (event
->group_leader
!= event
)
1460 event
= event
->group_leader
;
1462 event_type
= event
->attr
.pinned
? EVENT_PINNED
: EVENT_FLEXIBLE
;
1464 event_type
|= EVENT_CPU
;
1469 static struct list_head
*
1470 ctx_group_list(struct perf_event
*event
, struct perf_event_context
*ctx
)
1472 if (event
->attr
.pinned
)
1473 return &ctx
->pinned_groups
;
1475 return &ctx
->flexible_groups
;
1479 * Add a event from the lists for its context.
1480 * Must be called with ctx->mutex and ctx->lock held.
1483 list_add_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
1485 lockdep_assert_held(&ctx
->lock
);
1487 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_CONTEXT
);
1488 event
->attach_state
|= PERF_ATTACH_CONTEXT
;
1491 * If we're a stand alone event or group leader, we go to the context
1492 * list, group events are kept attached to the group so that
1493 * perf_group_detach can, at all times, locate all siblings.
1495 if (event
->group_leader
== event
) {
1496 struct list_head
*list
;
1498 event
->group_caps
= event
->event_caps
;
1500 list
= ctx_group_list(event
, ctx
);
1501 list_add_tail(&event
->group_entry
, list
);
1504 list_update_cgroup_event(event
, ctx
, true);
1506 list_add_rcu(&event
->event_entry
, &ctx
->event_list
);
1508 if (event
->attr
.inherit_stat
)
1515 * Initialize event state based on the perf_event_attr::disabled.
1517 static inline void perf_event__state_init(struct perf_event
*event
)
1519 event
->state
= event
->attr
.disabled
? PERF_EVENT_STATE_OFF
:
1520 PERF_EVENT_STATE_INACTIVE
;
1523 static void __perf_event_read_size(struct perf_event
*event
, int nr_siblings
)
1525 int entry
= sizeof(u64
); /* value */
1529 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1530 size
+= sizeof(u64
);
1532 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1533 size
+= sizeof(u64
);
1535 if (event
->attr
.read_format
& PERF_FORMAT_ID
)
1536 entry
+= sizeof(u64
);
1538 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
) {
1540 size
+= sizeof(u64
);
1544 event
->read_size
= size
;
1547 static void __perf_event_header_size(struct perf_event
*event
, u64 sample_type
)
1549 struct perf_sample_data
*data
;
1552 if (sample_type
& PERF_SAMPLE_IP
)
1553 size
+= sizeof(data
->ip
);
1555 if (sample_type
& PERF_SAMPLE_ADDR
)
1556 size
+= sizeof(data
->addr
);
1558 if (sample_type
& PERF_SAMPLE_PERIOD
)
1559 size
+= sizeof(data
->period
);
1561 if (sample_type
& PERF_SAMPLE_WEIGHT
)
1562 size
+= sizeof(data
->weight
);
1564 if (sample_type
& PERF_SAMPLE_READ
)
1565 size
+= event
->read_size
;
1567 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
1568 size
+= sizeof(data
->data_src
.val
);
1570 if (sample_type
& PERF_SAMPLE_TRANSACTION
)
1571 size
+= sizeof(data
->txn
);
1573 event
->header_size
= size
;
1577 * Called at perf_event creation and when events are attached/detached from a
1580 static void perf_event__header_size(struct perf_event
*event
)
1582 __perf_event_read_size(event
,
1583 event
->group_leader
->nr_siblings
);
1584 __perf_event_header_size(event
, event
->attr
.sample_type
);
1587 static void perf_event__id_header_size(struct perf_event
*event
)
1589 struct perf_sample_data
*data
;
1590 u64 sample_type
= event
->attr
.sample_type
;
1593 if (sample_type
& PERF_SAMPLE_TID
)
1594 size
+= sizeof(data
->tid_entry
);
1596 if (sample_type
& PERF_SAMPLE_TIME
)
1597 size
+= sizeof(data
->time
);
1599 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
1600 size
+= sizeof(data
->id
);
1602 if (sample_type
& PERF_SAMPLE_ID
)
1603 size
+= sizeof(data
->id
);
1605 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
1606 size
+= sizeof(data
->stream_id
);
1608 if (sample_type
& PERF_SAMPLE_CPU
)
1609 size
+= sizeof(data
->cpu_entry
);
1611 event
->id_header_size
= size
;
1614 static bool perf_event_validate_size(struct perf_event
*event
)
1617 * The values computed here will be over-written when we actually
1620 __perf_event_read_size(event
, event
->group_leader
->nr_siblings
+ 1);
1621 __perf_event_header_size(event
, event
->attr
.sample_type
& ~PERF_SAMPLE_READ
);
1622 perf_event__id_header_size(event
);
1625 * Sum the lot; should not exceed the 64k limit we have on records.
1626 * Conservative limit to allow for callchains and other variable fields.
1628 if (event
->read_size
+ event
->header_size
+
1629 event
->id_header_size
+ sizeof(struct perf_event_header
) >= 16*1024)
1635 static void perf_group_attach(struct perf_event
*event
)
1637 struct perf_event
*group_leader
= event
->group_leader
, *pos
;
1639 lockdep_assert_held(&event
->ctx
->lock
);
1642 * We can have double attach due to group movement in perf_event_open.
1644 if (event
->attach_state
& PERF_ATTACH_GROUP
)
1647 event
->attach_state
|= PERF_ATTACH_GROUP
;
1649 if (group_leader
== event
)
1652 WARN_ON_ONCE(group_leader
->ctx
!= event
->ctx
);
1654 group_leader
->group_caps
&= event
->event_caps
;
1656 list_add_tail(&event
->group_entry
, &group_leader
->sibling_list
);
1657 group_leader
->nr_siblings
++;
1659 perf_event__header_size(group_leader
);
1661 list_for_each_entry(pos
, &group_leader
->sibling_list
, group_entry
)
1662 perf_event__header_size(pos
);
1666 * Remove a event from the lists for its context.
1667 * Must be called with ctx->mutex and ctx->lock held.
1670 list_del_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
1672 WARN_ON_ONCE(event
->ctx
!= ctx
);
1673 lockdep_assert_held(&ctx
->lock
);
1676 * We can have double detach due to exit/hot-unplug + close.
1678 if (!(event
->attach_state
& PERF_ATTACH_CONTEXT
))
1681 event
->attach_state
&= ~PERF_ATTACH_CONTEXT
;
1683 list_update_cgroup_event(event
, ctx
, false);
1686 if (event
->attr
.inherit_stat
)
1689 list_del_rcu(&event
->event_entry
);
1691 if (event
->group_leader
== event
)
1692 list_del_init(&event
->group_entry
);
1694 update_group_times(event
);
1697 * If event was in error state, then keep it
1698 * that way, otherwise bogus counts will be
1699 * returned on read(). The only way to get out
1700 * of error state is by explicit re-enabling
1703 if (event
->state
> PERF_EVENT_STATE_OFF
)
1704 event
->state
= PERF_EVENT_STATE_OFF
;
1709 static void perf_group_detach(struct perf_event
*event
)
1711 struct perf_event
*sibling
, *tmp
;
1712 struct list_head
*list
= NULL
;
1714 lockdep_assert_held(&event
->ctx
->lock
);
1717 * We can have double detach due to exit/hot-unplug + close.
1719 if (!(event
->attach_state
& PERF_ATTACH_GROUP
))
1722 event
->attach_state
&= ~PERF_ATTACH_GROUP
;
1725 * If this is a sibling, remove it from its group.
1727 if (event
->group_leader
!= event
) {
1728 list_del_init(&event
->group_entry
);
1729 event
->group_leader
->nr_siblings
--;
1733 if (!list_empty(&event
->group_entry
))
1734 list
= &event
->group_entry
;
1737 * If this was a group event with sibling events then
1738 * upgrade the siblings to singleton events by adding them
1739 * to whatever list we are on.
1741 list_for_each_entry_safe(sibling
, tmp
, &event
->sibling_list
, group_entry
) {
1743 list_move_tail(&sibling
->group_entry
, list
);
1744 sibling
->group_leader
= sibling
;
1746 /* Inherit group flags from the previous leader */
1747 sibling
->group_caps
= event
->group_caps
;
1749 WARN_ON_ONCE(sibling
->ctx
!= event
->ctx
);
1753 perf_event__header_size(event
->group_leader
);
1755 list_for_each_entry(tmp
, &event
->group_leader
->sibling_list
, group_entry
)
1756 perf_event__header_size(tmp
);
1759 static bool is_orphaned_event(struct perf_event
*event
)
1761 return event
->state
== PERF_EVENT_STATE_DEAD
;
1764 static inline int __pmu_filter_match(struct perf_event
*event
)
1766 struct pmu
*pmu
= event
->pmu
;
1767 return pmu
->filter_match
? pmu
->filter_match(event
) : 1;
1771 * Check whether we should attempt to schedule an event group based on
1772 * PMU-specific filtering. An event group can consist of HW and SW events,
1773 * potentially with a SW leader, so we must check all the filters, to
1774 * determine whether a group is schedulable:
1776 static inline int pmu_filter_match(struct perf_event
*event
)
1778 struct perf_event
*child
;
1780 if (!__pmu_filter_match(event
))
1783 list_for_each_entry(child
, &event
->sibling_list
, group_entry
) {
1784 if (!__pmu_filter_match(child
))
1792 event_filter_match(struct perf_event
*event
)
1794 return (event
->cpu
== -1 || event
->cpu
== smp_processor_id()) &&
1795 perf_cgroup_match(event
) && pmu_filter_match(event
);
1799 event_sched_out(struct perf_event
*event
,
1800 struct perf_cpu_context
*cpuctx
,
1801 struct perf_event_context
*ctx
)
1803 u64 tstamp
= perf_event_time(event
);
1806 WARN_ON_ONCE(event
->ctx
!= ctx
);
1807 lockdep_assert_held(&ctx
->lock
);
1810 * An event which could not be activated because of
1811 * filter mismatch still needs to have its timings
1812 * maintained, otherwise bogus information is return
1813 * via read() for time_enabled, time_running:
1815 if (event
->state
== PERF_EVENT_STATE_INACTIVE
&&
1816 !event_filter_match(event
)) {
1817 delta
= tstamp
- event
->tstamp_stopped
;
1818 event
->tstamp_running
+= delta
;
1819 event
->tstamp_stopped
= tstamp
;
1822 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
1825 perf_pmu_disable(event
->pmu
);
1827 event
->tstamp_stopped
= tstamp
;
1828 event
->pmu
->del(event
, 0);
1830 event
->state
= PERF_EVENT_STATE_INACTIVE
;
1831 if (event
->pending_disable
) {
1832 event
->pending_disable
= 0;
1833 event
->state
= PERF_EVENT_STATE_OFF
;
1836 if (!is_software_event(event
))
1837 cpuctx
->active_oncpu
--;
1838 if (!--ctx
->nr_active
)
1839 perf_event_ctx_deactivate(ctx
);
1840 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
1842 if (event
->attr
.exclusive
|| !cpuctx
->active_oncpu
)
1843 cpuctx
->exclusive
= 0;
1845 perf_pmu_enable(event
->pmu
);
1849 group_sched_out(struct perf_event
*group_event
,
1850 struct perf_cpu_context
*cpuctx
,
1851 struct perf_event_context
*ctx
)
1853 struct perf_event
*event
;
1854 int state
= group_event
->state
;
1856 perf_pmu_disable(ctx
->pmu
);
1858 event_sched_out(group_event
, cpuctx
, ctx
);
1861 * Schedule out siblings (if any):
1863 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
)
1864 event_sched_out(event
, cpuctx
, ctx
);
1866 perf_pmu_enable(ctx
->pmu
);
1868 if (state
== PERF_EVENT_STATE_ACTIVE
&& group_event
->attr
.exclusive
)
1869 cpuctx
->exclusive
= 0;
1872 #define DETACH_GROUP 0x01UL
1875 * Cross CPU call to remove a performance event
1877 * We disable the event on the hardware level first. After that we
1878 * remove it from the context list.
1881 __perf_remove_from_context(struct perf_event
*event
,
1882 struct perf_cpu_context
*cpuctx
,
1883 struct perf_event_context
*ctx
,
1886 unsigned long flags
= (unsigned long)info
;
1888 event_sched_out(event
, cpuctx
, ctx
);
1889 if (flags
& DETACH_GROUP
)
1890 perf_group_detach(event
);
1891 list_del_event(event
, ctx
);
1893 if (!ctx
->nr_events
&& ctx
->is_active
) {
1896 WARN_ON_ONCE(cpuctx
->task_ctx
!= ctx
);
1897 cpuctx
->task_ctx
= NULL
;
1903 * Remove the event from a task's (or a CPU's) list of events.
1905 * If event->ctx is a cloned context, callers must make sure that
1906 * every task struct that event->ctx->task could possibly point to
1907 * remains valid. This is OK when called from perf_release since
1908 * that only calls us on the top-level context, which can't be a clone.
1909 * When called from perf_event_exit_task, it's OK because the
1910 * context has been detached from its task.
1912 static void perf_remove_from_context(struct perf_event
*event
, unsigned long flags
)
1914 struct perf_event_context
*ctx
= event
->ctx
;
1916 lockdep_assert_held(&ctx
->mutex
);
1918 event_function_call(event
, __perf_remove_from_context
, (void *)flags
);
1921 * The above event_function_call() can NO-OP when it hits
1922 * TASK_TOMBSTONE. In that case we must already have been detached
1923 * from the context (by perf_event_exit_event()) but the grouping
1924 * might still be in-tact.
1926 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_CONTEXT
);
1927 if ((flags
& DETACH_GROUP
) &&
1928 (event
->attach_state
& PERF_ATTACH_GROUP
)) {
1930 * Since in that case we cannot possibly be scheduled, simply
1933 raw_spin_lock_irq(&ctx
->lock
);
1934 perf_group_detach(event
);
1935 raw_spin_unlock_irq(&ctx
->lock
);
1940 * Cross CPU call to disable a performance event
1942 static void __perf_event_disable(struct perf_event
*event
,
1943 struct perf_cpu_context
*cpuctx
,
1944 struct perf_event_context
*ctx
,
1947 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
1950 update_context_time(ctx
);
1951 update_cgrp_time_from_event(event
);
1952 update_group_times(event
);
1953 if (event
== event
->group_leader
)
1954 group_sched_out(event
, cpuctx
, ctx
);
1956 event_sched_out(event
, cpuctx
, ctx
);
1957 event
->state
= PERF_EVENT_STATE_OFF
;
1963 * If event->ctx is a cloned context, callers must make sure that
1964 * every task struct that event->ctx->task could possibly point to
1965 * remains valid. This condition is satisifed when called through
1966 * perf_event_for_each_child or perf_event_for_each because they
1967 * hold the top-level event's child_mutex, so any descendant that
1968 * goes to exit will block in perf_event_exit_event().
1970 * When called from perf_pending_event it's OK because event->ctx
1971 * is the current context on this CPU and preemption is disabled,
1972 * hence we can't get into perf_event_task_sched_out for this context.
1974 static void _perf_event_disable(struct perf_event
*event
)
1976 struct perf_event_context
*ctx
= event
->ctx
;
1978 raw_spin_lock_irq(&ctx
->lock
);
1979 if (event
->state
<= PERF_EVENT_STATE_OFF
) {
1980 raw_spin_unlock_irq(&ctx
->lock
);
1983 raw_spin_unlock_irq(&ctx
->lock
);
1985 event_function_call(event
, __perf_event_disable
, NULL
);
1988 void perf_event_disable_local(struct perf_event
*event
)
1990 event_function_local(event
, __perf_event_disable
, NULL
);
1994 * Strictly speaking kernel users cannot create groups and therefore this
1995 * interface does not need the perf_event_ctx_lock() magic.
1997 void perf_event_disable(struct perf_event
*event
)
1999 struct perf_event_context
*ctx
;
2001 ctx
= perf_event_ctx_lock(event
);
2002 _perf_event_disable(event
);
2003 perf_event_ctx_unlock(event
, ctx
);
2005 EXPORT_SYMBOL_GPL(perf_event_disable
);
2007 void perf_event_disable_inatomic(struct perf_event
*event
)
2009 event
->pending_disable
= 1;
2010 irq_work_queue(&event
->pending
);
2013 static void perf_set_shadow_time(struct perf_event
*event
,
2014 struct perf_event_context
*ctx
,
2018 * use the correct time source for the time snapshot
2020 * We could get by without this by leveraging the
2021 * fact that to get to this function, the caller
2022 * has most likely already called update_context_time()
2023 * and update_cgrp_time_xx() and thus both timestamp
2024 * are identical (or very close). Given that tstamp is,
2025 * already adjusted for cgroup, we could say that:
2026 * tstamp - ctx->timestamp
2028 * tstamp - cgrp->timestamp.
2030 * Then, in perf_output_read(), the calculation would
2031 * work with no changes because:
2032 * - event is guaranteed scheduled in
2033 * - no scheduled out in between
2034 * - thus the timestamp would be the same
2036 * But this is a bit hairy.
2038 * So instead, we have an explicit cgroup call to remain
2039 * within the time time source all along. We believe it
2040 * is cleaner and simpler to understand.
2042 if (is_cgroup_event(event
))
2043 perf_cgroup_set_shadow_time(event
, tstamp
);
2045 event
->shadow_ctx_time
= tstamp
- ctx
->timestamp
;
2048 #define MAX_INTERRUPTS (~0ULL)
2050 static void perf_log_throttle(struct perf_event
*event
, int enable
);
2051 static void perf_log_itrace_start(struct perf_event
*event
);
2054 event_sched_in(struct perf_event
*event
,
2055 struct perf_cpu_context
*cpuctx
,
2056 struct perf_event_context
*ctx
)
2058 u64 tstamp
= perf_event_time(event
);
2061 lockdep_assert_held(&ctx
->lock
);
2063 if (event
->state
<= PERF_EVENT_STATE_OFF
)
2066 WRITE_ONCE(event
->oncpu
, smp_processor_id());
2068 * Order event::oncpu write to happen before the ACTIVE state
2072 WRITE_ONCE(event
->state
, PERF_EVENT_STATE_ACTIVE
);
2075 * Unthrottle events, since we scheduled we might have missed several
2076 * ticks already, also for a heavily scheduling task there is little
2077 * guarantee it'll get a tick in a timely manner.
2079 if (unlikely(event
->hw
.interrupts
== MAX_INTERRUPTS
)) {
2080 perf_log_throttle(event
, 1);
2081 event
->hw
.interrupts
= 0;
2085 * The new state must be visible before we turn it on in the hardware:
2089 perf_pmu_disable(event
->pmu
);
2091 perf_set_shadow_time(event
, ctx
, tstamp
);
2093 perf_log_itrace_start(event
);
2095 if (event
->pmu
->add(event
, PERF_EF_START
)) {
2096 event
->state
= PERF_EVENT_STATE_INACTIVE
;
2102 event
->tstamp_running
+= tstamp
- event
->tstamp_stopped
;
2104 if (!is_software_event(event
))
2105 cpuctx
->active_oncpu
++;
2106 if (!ctx
->nr_active
++)
2107 perf_event_ctx_activate(ctx
);
2108 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
2111 if (event
->attr
.exclusive
)
2112 cpuctx
->exclusive
= 1;
2115 perf_pmu_enable(event
->pmu
);
2121 group_sched_in(struct perf_event
*group_event
,
2122 struct perf_cpu_context
*cpuctx
,
2123 struct perf_event_context
*ctx
)
2125 struct perf_event
*event
, *partial_group
= NULL
;
2126 struct pmu
*pmu
= ctx
->pmu
;
2127 u64 now
= ctx
->time
;
2128 bool simulate
= false;
2130 if (group_event
->state
== PERF_EVENT_STATE_OFF
)
2133 pmu
->start_txn(pmu
, PERF_PMU_TXN_ADD
);
2135 if (event_sched_in(group_event
, cpuctx
, ctx
)) {
2136 pmu
->cancel_txn(pmu
);
2137 perf_mux_hrtimer_restart(cpuctx
);
2142 * Schedule in siblings as one group (if any):
2144 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
2145 if (event_sched_in(event
, cpuctx
, ctx
)) {
2146 partial_group
= event
;
2151 if (!pmu
->commit_txn(pmu
))
2156 * Groups can be scheduled in as one unit only, so undo any
2157 * partial group before returning:
2158 * The events up to the failed event are scheduled out normally,
2159 * tstamp_stopped will be updated.
2161 * The failed events and the remaining siblings need to have
2162 * their timings updated as if they had gone thru event_sched_in()
2163 * and event_sched_out(). This is required to get consistent timings
2164 * across the group. This also takes care of the case where the group
2165 * could never be scheduled by ensuring tstamp_stopped is set to mark
2166 * the time the event was actually stopped, such that time delta
2167 * calculation in update_event_times() is correct.
2169 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
2170 if (event
== partial_group
)
2174 event
->tstamp_running
+= now
- event
->tstamp_stopped
;
2175 event
->tstamp_stopped
= now
;
2177 event_sched_out(event
, cpuctx
, ctx
);
2180 event_sched_out(group_event
, cpuctx
, ctx
);
2182 pmu
->cancel_txn(pmu
);
2184 perf_mux_hrtimer_restart(cpuctx
);
2190 * Work out whether we can put this event group on the CPU now.
2192 static int group_can_go_on(struct perf_event
*event
,
2193 struct perf_cpu_context
*cpuctx
,
2197 * Groups consisting entirely of software events can always go on.
2199 if (event
->group_caps
& PERF_EV_CAP_SOFTWARE
)
2202 * If an exclusive group is already on, no other hardware
2205 if (cpuctx
->exclusive
)
2208 * If this group is exclusive and there are already
2209 * events on the CPU, it can't go on.
2211 if (event
->attr
.exclusive
&& cpuctx
->active_oncpu
)
2214 * Otherwise, try to add it if all previous groups were able
2220 static void add_event_to_ctx(struct perf_event
*event
,
2221 struct perf_event_context
*ctx
)
2223 u64 tstamp
= perf_event_time(event
);
2225 list_add_event(event
, ctx
);
2226 perf_group_attach(event
);
2227 event
->tstamp_enabled
= tstamp
;
2228 event
->tstamp_running
= tstamp
;
2229 event
->tstamp_stopped
= tstamp
;
2232 static void ctx_sched_out(struct perf_event_context
*ctx
,
2233 struct perf_cpu_context
*cpuctx
,
2234 enum event_type_t event_type
);
2236 ctx_sched_in(struct perf_event_context
*ctx
,
2237 struct perf_cpu_context
*cpuctx
,
2238 enum event_type_t event_type
,
2239 struct task_struct
*task
);
2241 static void task_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
2242 struct perf_event_context
*ctx
,
2243 enum event_type_t event_type
)
2245 if (!cpuctx
->task_ctx
)
2248 if (WARN_ON_ONCE(ctx
!= cpuctx
->task_ctx
))
2251 ctx_sched_out(ctx
, cpuctx
, event_type
);
2254 static void perf_event_sched_in(struct perf_cpu_context
*cpuctx
,
2255 struct perf_event_context
*ctx
,
2256 struct task_struct
*task
)
2258 cpu_ctx_sched_in(cpuctx
, EVENT_PINNED
, task
);
2260 ctx_sched_in(ctx
, cpuctx
, EVENT_PINNED
, task
);
2261 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
, task
);
2263 ctx_sched_in(ctx
, cpuctx
, EVENT_FLEXIBLE
, task
);
2267 * We want to maintain the following priority of scheduling:
2268 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2269 * - task pinned (EVENT_PINNED)
2270 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2271 * - task flexible (EVENT_FLEXIBLE).
2273 * In order to avoid unscheduling and scheduling back in everything every
2274 * time an event is added, only do it for the groups of equal priority and
2277 * This can be called after a batch operation on task events, in which case
2278 * event_type is a bit mask of the types of events involved. For CPU events,
2279 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2281 static void ctx_resched(struct perf_cpu_context
*cpuctx
,
2282 struct perf_event_context
*task_ctx
,
2283 enum event_type_t event_type
)
2285 enum event_type_t ctx_event_type
= event_type
& EVENT_ALL
;
2286 bool cpu_event
= !!(event_type
& EVENT_CPU
);
2289 * If pinned groups are involved, flexible groups also need to be
2292 if (event_type
& EVENT_PINNED
)
2293 event_type
|= EVENT_FLEXIBLE
;
2295 perf_pmu_disable(cpuctx
->ctx
.pmu
);
2297 task_ctx_sched_out(cpuctx
, task_ctx
, event_type
);
2300 * Decide which cpu ctx groups to schedule out based on the types
2301 * of events that caused rescheduling:
2302 * - EVENT_CPU: schedule out corresponding groups;
2303 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2304 * - otherwise, do nothing more.
2307 cpu_ctx_sched_out(cpuctx
, ctx_event_type
);
2308 else if (ctx_event_type
& EVENT_PINNED
)
2309 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
2311 perf_event_sched_in(cpuctx
, task_ctx
, current
);
2312 perf_pmu_enable(cpuctx
->ctx
.pmu
);
2316 * Cross CPU call to install and enable a performance event
2318 * Very similar to remote_function() + event_function() but cannot assume that
2319 * things like ctx->is_active and cpuctx->task_ctx are set.
2321 static int __perf_install_in_context(void *info
)
2323 struct perf_event
*event
= info
;
2324 struct perf_event_context
*ctx
= event
->ctx
;
2325 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
2326 struct perf_event_context
*task_ctx
= cpuctx
->task_ctx
;
2327 bool reprogram
= true;
2330 raw_spin_lock(&cpuctx
->ctx
.lock
);
2332 raw_spin_lock(&ctx
->lock
);
2335 reprogram
= (ctx
->task
== current
);
2338 * If the task is running, it must be running on this CPU,
2339 * otherwise we cannot reprogram things.
2341 * If its not running, we don't care, ctx->lock will
2342 * serialize against it becoming runnable.
2344 if (task_curr(ctx
->task
) && !reprogram
) {
2349 WARN_ON_ONCE(reprogram
&& cpuctx
->task_ctx
&& cpuctx
->task_ctx
!= ctx
);
2350 } else if (task_ctx
) {
2351 raw_spin_lock(&task_ctx
->lock
);
2355 ctx_sched_out(ctx
, cpuctx
, EVENT_TIME
);
2356 add_event_to_ctx(event
, ctx
);
2357 ctx_resched(cpuctx
, task_ctx
, get_event_type(event
));
2359 add_event_to_ctx(event
, ctx
);
2363 perf_ctx_unlock(cpuctx
, task_ctx
);
2369 * Attach a performance event to a context.
2371 * Very similar to event_function_call, see comment there.
2374 perf_install_in_context(struct perf_event_context
*ctx
,
2375 struct perf_event
*event
,
2378 struct task_struct
*task
= READ_ONCE(ctx
->task
);
2380 lockdep_assert_held(&ctx
->mutex
);
2382 if (event
->cpu
!= -1)
2386 * Ensures that if we can observe event->ctx, both the event and ctx
2387 * will be 'complete'. See perf_iterate_sb_cpu().
2389 smp_store_release(&event
->ctx
, ctx
);
2392 cpu_function_call(cpu
, __perf_install_in_context
, event
);
2397 * Should not happen, we validate the ctx is still alive before calling.
2399 if (WARN_ON_ONCE(task
== TASK_TOMBSTONE
))
2403 * Installing events is tricky because we cannot rely on ctx->is_active
2404 * to be set in case this is the nr_events 0 -> 1 transition.
2406 * Instead we use task_curr(), which tells us if the task is running.
2407 * However, since we use task_curr() outside of rq::lock, we can race
2408 * against the actual state. This means the result can be wrong.
2410 * If we get a false positive, we retry, this is harmless.
2412 * If we get a false negative, things are complicated. If we are after
2413 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2414 * value must be correct. If we're before, it doesn't matter since
2415 * perf_event_context_sched_in() will program the counter.
2417 * However, this hinges on the remote context switch having observed
2418 * our task->perf_event_ctxp[] store, such that it will in fact take
2419 * ctx::lock in perf_event_context_sched_in().
2421 * We do this by task_function_call(), if the IPI fails to hit the task
2422 * we know any future context switch of task must see the
2423 * perf_event_ctpx[] store.
2427 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2428 * task_cpu() load, such that if the IPI then does not find the task
2429 * running, a future context switch of that task must observe the
2434 if (!task_function_call(task
, __perf_install_in_context
, event
))
2437 raw_spin_lock_irq(&ctx
->lock
);
2439 if (WARN_ON_ONCE(task
== TASK_TOMBSTONE
)) {
2441 * Cannot happen because we already checked above (which also
2442 * cannot happen), and we hold ctx->mutex, which serializes us
2443 * against perf_event_exit_task_context().
2445 raw_spin_unlock_irq(&ctx
->lock
);
2449 * If the task is not running, ctx->lock will avoid it becoming so,
2450 * thus we can safely install the event.
2452 if (task_curr(task
)) {
2453 raw_spin_unlock_irq(&ctx
->lock
);
2456 add_event_to_ctx(event
, ctx
);
2457 raw_spin_unlock_irq(&ctx
->lock
);
2461 * Put a event into inactive state and update time fields.
2462 * Enabling the leader of a group effectively enables all
2463 * the group members that aren't explicitly disabled, so we
2464 * have to update their ->tstamp_enabled also.
2465 * Note: this works for group members as well as group leaders
2466 * since the non-leader members' sibling_lists will be empty.
2468 static void __perf_event_mark_enabled(struct perf_event
*event
)
2470 struct perf_event
*sub
;
2471 u64 tstamp
= perf_event_time(event
);
2473 event
->state
= PERF_EVENT_STATE_INACTIVE
;
2474 event
->tstamp_enabled
= tstamp
- event
->total_time_enabled
;
2475 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
2476 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
)
2477 sub
->tstamp_enabled
= tstamp
- sub
->total_time_enabled
;
2482 * Cross CPU call to enable a performance event
2484 static void __perf_event_enable(struct perf_event
*event
,
2485 struct perf_cpu_context
*cpuctx
,
2486 struct perf_event_context
*ctx
,
2489 struct perf_event
*leader
= event
->group_leader
;
2490 struct perf_event_context
*task_ctx
;
2492 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
||
2493 event
->state
<= PERF_EVENT_STATE_ERROR
)
2497 ctx_sched_out(ctx
, cpuctx
, EVENT_TIME
);
2499 __perf_event_mark_enabled(event
);
2501 if (!ctx
->is_active
)
2504 if (!event_filter_match(event
)) {
2505 if (is_cgroup_event(event
))
2506 perf_cgroup_defer_enabled(event
);
2507 ctx_sched_in(ctx
, cpuctx
, EVENT_TIME
, current
);
2512 * If the event is in a group and isn't the group leader,
2513 * then don't put it on unless the group is on.
2515 if (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
) {
2516 ctx_sched_in(ctx
, cpuctx
, EVENT_TIME
, current
);
2520 task_ctx
= cpuctx
->task_ctx
;
2522 WARN_ON_ONCE(task_ctx
!= ctx
);
2524 ctx_resched(cpuctx
, task_ctx
, get_event_type(event
));
2530 * If event->ctx is a cloned context, callers must make sure that
2531 * every task struct that event->ctx->task could possibly point to
2532 * remains valid. This condition is satisfied when called through
2533 * perf_event_for_each_child or perf_event_for_each as described
2534 * for perf_event_disable.
2536 static void _perf_event_enable(struct perf_event
*event
)
2538 struct perf_event_context
*ctx
= event
->ctx
;
2540 raw_spin_lock_irq(&ctx
->lock
);
2541 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
||
2542 event
->state
< PERF_EVENT_STATE_ERROR
) {
2543 raw_spin_unlock_irq(&ctx
->lock
);
2548 * If the event is in error state, clear that first.
2550 * That way, if we see the event in error state below, we know that it
2551 * has gone back into error state, as distinct from the task having
2552 * been scheduled away before the cross-call arrived.
2554 if (event
->state
== PERF_EVENT_STATE_ERROR
)
2555 event
->state
= PERF_EVENT_STATE_OFF
;
2556 raw_spin_unlock_irq(&ctx
->lock
);
2558 event_function_call(event
, __perf_event_enable
, NULL
);
2562 * See perf_event_disable();
2564 void perf_event_enable(struct perf_event
*event
)
2566 struct perf_event_context
*ctx
;
2568 ctx
= perf_event_ctx_lock(event
);
2569 _perf_event_enable(event
);
2570 perf_event_ctx_unlock(event
, ctx
);
2572 EXPORT_SYMBOL_GPL(perf_event_enable
);
2574 struct stop_event_data
{
2575 struct perf_event
*event
;
2576 unsigned int restart
;
2579 static int __perf_event_stop(void *info
)
2581 struct stop_event_data
*sd
= info
;
2582 struct perf_event
*event
= sd
->event
;
2584 /* if it's already INACTIVE, do nothing */
2585 if (READ_ONCE(event
->state
) != PERF_EVENT_STATE_ACTIVE
)
2588 /* matches smp_wmb() in event_sched_in() */
2592 * There is a window with interrupts enabled before we get here,
2593 * so we need to check again lest we try to stop another CPU's event.
2595 if (READ_ONCE(event
->oncpu
) != smp_processor_id())
2598 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
2601 * May race with the actual stop (through perf_pmu_output_stop()),
2602 * but it is only used for events with AUX ring buffer, and such
2603 * events will refuse to restart because of rb::aux_mmap_count==0,
2604 * see comments in perf_aux_output_begin().
2606 * Since this is happening on a event-local CPU, no trace is lost
2610 event
->pmu
->start(event
, 0);
2615 static int perf_event_stop(struct perf_event
*event
, int restart
)
2617 struct stop_event_data sd
= {
2624 if (READ_ONCE(event
->state
) != PERF_EVENT_STATE_ACTIVE
)
2627 /* matches smp_wmb() in event_sched_in() */
2631 * We only want to restart ACTIVE events, so if the event goes
2632 * inactive here (event->oncpu==-1), there's nothing more to do;
2633 * fall through with ret==-ENXIO.
2635 ret
= cpu_function_call(READ_ONCE(event
->oncpu
),
2636 __perf_event_stop
, &sd
);
2637 } while (ret
== -EAGAIN
);
2643 * In order to contain the amount of racy and tricky in the address filter
2644 * configuration management, it is a two part process:
2646 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2647 * we update the addresses of corresponding vmas in
2648 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2649 * (p2) when an event is scheduled in (pmu::add), it calls
2650 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2651 * if the generation has changed since the previous call.
2653 * If (p1) happens while the event is active, we restart it to force (p2).
2655 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2656 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2658 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2659 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2661 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2664 void perf_event_addr_filters_sync(struct perf_event
*event
)
2666 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
2668 if (!has_addr_filter(event
))
2671 raw_spin_lock(&ifh
->lock
);
2672 if (event
->addr_filters_gen
!= event
->hw
.addr_filters_gen
) {
2673 event
->pmu
->addr_filters_sync(event
);
2674 event
->hw
.addr_filters_gen
= event
->addr_filters_gen
;
2676 raw_spin_unlock(&ifh
->lock
);
2678 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync
);
2680 static int _perf_event_refresh(struct perf_event
*event
, int refresh
)
2683 * not supported on inherited events
2685 if (event
->attr
.inherit
|| !is_sampling_event(event
))
2688 atomic_add(refresh
, &event
->event_limit
);
2689 _perf_event_enable(event
);
2695 * See perf_event_disable()
2697 int perf_event_refresh(struct perf_event
*event
, int refresh
)
2699 struct perf_event_context
*ctx
;
2702 ctx
= perf_event_ctx_lock(event
);
2703 ret
= _perf_event_refresh(event
, refresh
);
2704 perf_event_ctx_unlock(event
, ctx
);
2708 EXPORT_SYMBOL_GPL(perf_event_refresh
);
2710 static void ctx_sched_out(struct perf_event_context
*ctx
,
2711 struct perf_cpu_context
*cpuctx
,
2712 enum event_type_t event_type
)
2714 int is_active
= ctx
->is_active
;
2715 struct perf_event
*event
;
2717 lockdep_assert_held(&ctx
->lock
);
2719 if (likely(!ctx
->nr_events
)) {
2721 * See __perf_remove_from_context().
2723 WARN_ON_ONCE(ctx
->is_active
);
2725 WARN_ON_ONCE(cpuctx
->task_ctx
);
2729 ctx
->is_active
&= ~event_type
;
2730 if (!(ctx
->is_active
& EVENT_ALL
))
2734 WARN_ON_ONCE(cpuctx
->task_ctx
!= ctx
);
2735 if (!ctx
->is_active
)
2736 cpuctx
->task_ctx
= NULL
;
2740 * Always update time if it was set; not only when it changes.
2741 * Otherwise we can 'forget' to update time for any but the last
2742 * context we sched out. For example:
2744 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2745 * ctx_sched_out(.event_type = EVENT_PINNED)
2747 * would only update time for the pinned events.
2749 if (is_active
& EVENT_TIME
) {
2750 /* update (and stop) ctx time */
2751 update_context_time(ctx
);
2752 update_cgrp_time_from_cpuctx(cpuctx
);
2755 is_active
^= ctx
->is_active
; /* changed bits */
2757 if (!ctx
->nr_active
|| !(is_active
& EVENT_ALL
))
2760 perf_pmu_disable(ctx
->pmu
);
2761 if (is_active
& EVENT_PINNED
) {
2762 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
)
2763 group_sched_out(event
, cpuctx
, ctx
);
2766 if (is_active
& EVENT_FLEXIBLE
) {
2767 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
)
2768 group_sched_out(event
, cpuctx
, ctx
);
2770 perf_pmu_enable(ctx
->pmu
);
2774 * Test whether two contexts are equivalent, i.e. whether they have both been
2775 * cloned from the same version of the same context.
2777 * Equivalence is measured using a generation number in the context that is
2778 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2779 * and list_del_event().
2781 static int context_equiv(struct perf_event_context
*ctx1
,
2782 struct perf_event_context
*ctx2
)
2784 lockdep_assert_held(&ctx1
->lock
);
2785 lockdep_assert_held(&ctx2
->lock
);
2787 /* Pinning disables the swap optimization */
2788 if (ctx1
->pin_count
|| ctx2
->pin_count
)
2791 /* If ctx1 is the parent of ctx2 */
2792 if (ctx1
== ctx2
->parent_ctx
&& ctx1
->generation
== ctx2
->parent_gen
)
2795 /* If ctx2 is the parent of ctx1 */
2796 if (ctx1
->parent_ctx
== ctx2
&& ctx1
->parent_gen
== ctx2
->generation
)
2800 * If ctx1 and ctx2 have the same parent; we flatten the parent
2801 * hierarchy, see perf_event_init_context().
2803 if (ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
&&
2804 ctx1
->parent_gen
== ctx2
->parent_gen
)
2811 static void __perf_event_sync_stat(struct perf_event
*event
,
2812 struct perf_event
*next_event
)
2816 if (!event
->attr
.inherit_stat
)
2820 * Update the event value, we cannot use perf_event_read()
2821 * because we're in the middle of a context switch and have IRQs
2822 * disabled, which upsets smp_call_function_single(), however
2823 * we know the event must be on the current CPU, therefore we
2824 * don't need to use it.
2826 switch (event
->state
) {
2827 case PERF_EVENT_STATE_ACTIVE
:
2828 event
->pmu
->read(event
);
2831 case PERF_EVENT_STATE_INACTIVE
:
2832 update_event_times(event
);
2840 * In order to keep per-task stats reliable we need to flip the event
2841 * values when we flip the contexts.
2843 value
= local64_read(&next_event
->count
);
2844 value
= local64_xchg(&event
->count
, value
);
2845 local64_set(&next_event
->count
, value
);
2847 swap(event
->total_time_enabled
, next_event
->total_time_enabled
);
2848 swap(event
->total_time_running
, next_event
->total_time_running
);
2851 * Since we swizzled the values, update the user visible data too.
2853 perf_event_update_userpage(event
);
2854 perf_event_update_userpage(next_event
);
2857 static void perf_event_sync_stat(struct perf_event_context
*ctx
,
2858 struct perf_event_context
*next_ctx
)
2860 struct perf_event
*event
, *next_event
;
2865 update_context_time(ctx
);
2867 event
= list_first_entry(&ctx
->event_list
,
2868 struct perf_event
, event_entry
);
2870 next_event
= list_first_entry(&next_ctx
->event_list
,
2871 struct perf_event
, event_entry
);
2873 while (&event
->event_entry
!= &ctx
->event_list
&&
2874 &next_event
->event_entry
!= &next_ctx
->event_list
) {
2876 __perf_event_sync_stat(event
, next_event
);
2878 event
= list_next_entry(event
, event_entry
);
2879 next_event
= list_next_entry(next_event
, event_entry
);
2883 static void perf_event_context_sched_out(struct task_struct
*task
, int ctxn
,
2884 struct task_struct
*next
)
2886 struct perf_event_context
*ctx
= task
->perf_event_ctxp
[ctxn
];
2887 struct perf_event_context
*next_ctx
;
2888 struct perf_event_context
*parent
, *next_parent
;
2889 struct perf_cpu_context
*cpuctx
;
2895 cpuctx
= __get_cpu_context(ctx
);
2896 if (!cpuctx
->task_ctx
)
2900 next_ctx
= next
->perf_event_ctxp
[ctxn
];
2904 parent
= rcu_dereference(ctx
->parent_ctx
);
2905 next_parent
= rcu_dereference(next_ctx
->parent_ctx
);
2907 /* If neither context have a parent context; they cannot be clones. */
2908 if (!parent
&& !next_parent
)
2911 if (next_parent
== ctx
|| next_ctx
== parent
|| next_parent
== parent
) {
2913 * Looks like the two contexts are clones, so we might be
2914 * able to optimize the context switch. We lock both
2915 * contexts and check that they are clones under the
2916 * lock (including re-checking that neither has been
2917 * uncloned in the meantime). It doesn't matter which
2918 * order we take the locks because no other cpu could
2919 * be trying to lock both of these tasks.
2921 raw_spin_lock(&ctx
->lock
);
2922 raw_spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
2923 if (context_equiv(ctx
, next_ctx
)) {
2924 WRITE_ONCE(ctx
->task
, next
);
2925 WRITE_ONCE(next_ctx
->task
, task
);
2927 swap(ctx
->task_ctx_data
, next_ctx
->task_ctx_data
);
2930 * RCU_INIT_POINTER here is safe because we've not
2931 * modified the ctx and the above modification of
2932 * ctx->task and ctx->task_ctx_data are immaterial
2933 * since those values are always verified under
2934 * ctx->lock which we're now holding.
2936 RCU_INIT_POINTER(task
->perf_event_ctxp
[ctxn
], next_ctx
);
2937 RCU_INIT_POINTER(next
->perf_event_ctxp
[ctxn
], ctx
);
2941 perf_event_sync_stat(ctx
, next_ctx
);
2943 raw_spin_unlock(&next_ctx
->lock
);
2944 raw_spin_unlock(&ctx
->lock
);
2950 raw_spin_lock(&ctx
->lock
);
2951 task_ctx_sched_out(cpuctx
, ctx
, EVENT_ALL
);
2952 raw_spin_unlock(&ctx
->lock
);
2956 static DEFINE_PER_CPU(struct list_head
, sched_cb_list
);
2958 void perf_sched_cb_dec(struct pmu
*pmu
)
2960 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
2962 this_cpu_dec(perf_sched_cb_usages
);
2964 if (!--cpuctx
->sched_cb_usage
)
2965 list_del(&cpuctx
->sched_cb_entry
);
2969 void perf_sched_cb_inc(struct pmu
*pmu
)
2971 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
2973 if (!cpuctx
->sched_cb_usage
++)
2974 list_add(&cpuctx
->sched_cb_entry
, this_cpu_ptr(&sched_cb_list
));
2976 this_cpu_inc(perf_sched_cb_usages
);
2980 * This function provides the context switch callback to the lower code
2981 * layer. It is invoked ONLY when the context switch callback is enabled.
2983 * This callback is relevant even to per-cpu events; for example multi event
2984 * PEBS requires this to provide PID/TID information. This requires we flush
2985 * all queued PEBS records before we context switch to a new task.
2987 static void perf_pmu_sched_task(struct task_struct
*prev
,
2988 struct task_struct
*next
,
2991 struct perf_cpu_context
*cpuctx
;
2997 list_for_each_entry(cpuctx
, this_cpu_ptr(&sched_cb_list
), sched_cb_entry
) {
2998 pmu
= cpuctx
->ctx
.pmu
; /* software PMUs will not have sched_task */
3000 if (WARN_ON_ONCE(!pmu
->sched_task
))
3003 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
3004 perf_pmu_disable(pmu
);
3006 pmu
->sched_task(cpuctx
->task_ctx
, sched_in
);
3008 perf_pmu_enable(pmu
);
3009 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
3013 static void perf_event_switch(struct task_struct
*task
,
3014 struct task_struct
*next_prev
, bool sched_in
);
3016 #define for_each_task_context_nr(ctxn) \
3017 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3020 * Called from scheduler to remove the events of the current task,
3021 * with interrupts disabled.
3023 * We stop each event and update the event value in event->count.
3025 * This does not protect us against NMI, but disable()
3026 * sets the disabled bit in the control field of event _before_
3027 * accessing the event control register. If a NMI hits, then it will
3028 * not restart the event.
3030 void __perf_event_task_sched_out(struct task_struct
*task
,
3031 struct task_struct
*next
)
3035 if (__this_cpu_read(perf_sched_cb_usages
))
3036 perf_pmu_sched_task(task
, next
, false);
3038 if (atomic_read(&nr_switch_events
))
3039 perf_event_switch(task
, next
, false);
3041 for_each_task_context_nr(ctxn
)
3042 perf_event_context_sched_out(task
, ctxn
, next
);
3045 * if cgroup events exist on this CPU, then we need
3046 * to check if we have to switch out PMU state.
3047 * cgroup event are system-wide mode only
3049 if (atomic_read(this_cpu_ptr(&perf_cgroup_events
)))
3050 perf_cgroup_sched_out(task
, next
);
3054 * Called with IRQs disabled
3056 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
3057 enum event_type_t event_type
)
3059 ctx_sched_out(&cpuctx
->ctx
, cpuctx
, event_type
);
3063 ctx_pinned_sched_in(struct perf_event_context
*ctx
,
3064 struct perf_cpu_context
*cpuctx
)
3066 struct perf_event
*event
;
3068 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
3069 if (event
->state
<= PERF_EVENT_STATE_OFF
)
3071 if (!event_filter_match(event
))
3074 /* may need to reset tstamp_enabled */
3075 if (is_cgroup_event(event
))
3076 perf_cgroup_mark_enabled(event
, ctx
);
3078 if (group_can_go_on(event
, cpuctx
, 1))
3079 group_sched_in(event
, cpuctx
, ctx
);
3082 * If this pinned group hasn't been scheduled,
3083 * put it in error state.
3085 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
3086 update_group_times(event
);
3087 event
->state
= PERF_EVENT_STATE_ERROR
;
3093 ctx_flexible_sched_in(struct perf_event_context
*ctx
,
3094 struct perf_cpu_context
*cpuctx
)
3096 struct perf_event
*event
;
3099 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
3100 /* Ignore events in OFF or ERROR state */
3101 if (event
->state
<= PERF_EVENT_STATE_OFF
)
3104 * Listen to the 'cpu' scheduling filter constraint
3107 if (!event_filter_match(event
))
3110 /* may need to reset tstamp_enabled */
3111 if (is_cgroup_event(event
))
3112 perf_cgroup_mark_enabled(event
, ctx
);
3114 if (group_can_go_on(event
, cpuctx
, can_add_hw
)) {
3115 if (group_sched_in(event
, cpuctx
, ctx
))
3122 ctx_sched_in(struct perf_event_context
*ctx
,
3123 struct perf_cpu_context
*cpuctx
,
3124 enum event_type_t event_type
,
3125 struct task_struct
*task
)
3127 int is_active
= ctx
->is_active
;
3130 lockdep_assert_held(&ctx
->lock
);
3132 if (likely(!ctx
->nr_events
))
3135 ctx
->is_active
|= (event_type
| EVENT_TIME
);
3138 cpuctx
->task_ctx
= ctx
;
3140 WARN_ON_ONCE(cpuctx
->task_ctx
!= ctx
);
3143 is_active
^= ctx
->is_active
; /* changed bits */
3145 if (is_active
& EVENT_TIME
) {
3146 /* start ctx time */
3148 ctx
->timestamp
= now
;
3149 perf_cgroup_set_timestamp(task
, ctx
);
3153 * First go through the list and put on any pinned groups
3154 * in order to give them the best chance of going on.
3156 if (is_active
& EVENT_PINNED
)
3157 ctx_pinned_sched_in(ctx
, cpuctx
);
3159 /* Then walk through the lower prio flexible groups */
3160 if (is_active
& EVENT_FLEXIBLE
)
3161 ctx_flexible_sched_in(ctx
, cpuctx
);
3164 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
3165 enum event_type_t event_type
,
3166 struct task_struct
*task
)
3168 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
3170 ctx_sched_in(ctx
, cpuctx
, event_type
, task
);
3173 static void perf_event_context_sched_in(struct perf_event_context
*ctx
,
3174 struct task_struct
*task
)
3176 struct perf_cpu_context
*cpuctx
;
3178 cpuctx
= __get_cpu_context(ctx
);
3179 if (cpuctx
->task_ctx
== ctx
)
3182 perf_ctx_lock(cpuctx
, ctx
);
3183 perf_pmu_disable(ctx
->pmu
);
3185 * We want to keep the following priority order:
3186 * cpu pinned (that don't need to move), task pinned,
3187 * cpu flexible, task flexible.
3189 * However, if task's ctx is not carrying any pinned
3190 * events, no need to flip the cpuctx's events around.
3192 if (!list_empty(&ctx
->pinned_groups
))
3193 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
3194 perf_event_sched_in(cpuctx
, ctx
, task
);
3195 perf_pmu_enable(ctx
->pmu
);
3196 perf_ctx_unlock(cpuctx
, ctx
);
3200 * Called from scheduler to add the events of the current task
3201 * with interrupts disabled.
3203 * We restore the event value and then enable it.
3205 * This does not protect us against NMI, but enable()
3206 * sets the enabled bit in the control field of event _before_
3207 * accessing the event control register. If a NMI hits, then it will
3208 * keep the event running.
3210 void __perf_event_task_sched_in(struct task_struct
*prev
,
3211 struct task_struct
*task
)
3213 struct perf_event_context
*ctx
;
3217 * If cgroup events exist on this CPU, then we need to check if we have
3218 * to switch in PMU state; cgroup event are system-wide mode only.
3220 * Since cgroup events are CPU events, we must schedule these in before
3221 * we schedule in the task events.
3223 if (atomic_read(this_cpu_ptr(&perf_cgroup_events
)))
3224 perf_cgroup_sched_in(prev
, task
);
3226 for_each_task_context_nr(ctxn
) {
3227 ctx
= task
->perf_event_ctxp
[ctxn
];
3231 perf_event_context_sched_in(ctx
, task
);
3234 if (atomic_read(&nr_switch_events
))
3235 perf_event_switch(task
, prev
, true);
3237 if (__this_cpu_read(perf_sched_cb_usages
))
3238 perf_pmu_sched_task(prev
, task
, true);
3241 static u64
perf_calculate_period(struct perf_event
*event
, u64 nsec
, u64 count
)
3243 u64 frequency
= event
->attr
.sample_freq
;
3244 u64 sec
= NSEC_PER_SEC
;
3245 u64 divisor
, dividend
;
3247 int count_fls
, nsec_fls
, frequency_fls
, sec_fls
;
3249 count_fls
= fls64(count
);
3250 nsec_fls
= fls64(nsec
);
3251 frequency_fls
= fls64(frequency
);
3255 * We got @count in @nsec, with a target of sample_freq HZ
3256 * the target period becomes:
3259 * period = -------------------
3260 * @nsec * sample_freq
3265 * Reduce accuracy by one bit such that @a and @b converge
3266 * to a similar magnitude.
3268 #define REDUCE_FLS(a, b) \
3270 if (a##_fls > b##_fls) { \
3280 * Reduce accuracy until either term fits in a u64, then proceed with
3281 * the other, so that finally we can do a u64/u64 division.
3283 while (count_fls
+ sec_fls
> 64 && nsec_fls
+ frequency_fls
> 64) {
3284 REDUCE_FLS(nsec
, frequency
);
3285 REDUCE_FLS(sec
, count
);
3288 if (count_fls
+ sec_fls
> 64) {
3289 divisor
= nsec
* frequency
;
3291 while (count_fls
+ sec_fls
> 64) {
3292 REDUCE_FLS(count
, sec
);
3296 dividend
= count
* sec
;
3298 dividend
= count
* sec
;
3300 while (nsec_fls
+ frequency_fls
> 64) {
3301 REDUCE_FLS(nsec
, frequency
);
3305 divisor
= nsec
* frequency
;
3311 return div64_u64(dividend
, divisor
);
3314 static DEFINE_PER_CPU(int, perf_throttled_count
);
3315 static DEFINE_PER_CPU(u64
, perf_throttled_seq
);
3317 static void perf_adjust_period(struct perf_event
*event
, u64 nsec
, u64 count
, bool disable
)
3319 struct hw_perf_event
*hwc
= &event
->hw
;
3320 s64 period
, sample_period
;
3323 period
= perf_calculate_period(event
, nsec
, count
);
3325 delta
= (s64
)(period
- hwc
->sample_period
);
3326 delta
= (delta
+ 7) / 8; /* low pass filter */
3328 sample_period
= hwc
->sample_period
+ delta
;
3333 hwc
->sample_period
= sample_period
;
3335 if (local64_read(&hwc
->period_left
) > 8*sample_period
) {
3337 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
3339 local64_set(&hwc
->period_left
, 0);
3342 event
->pmu
->start(event
, PERF_EF_RELOAD
);
3347 * combine freq adjustment with unthrottling to avoid two passes over the
3348 * events. At the same time, make sure, having freq events does not change
3349 * the rate of unthrottling as that would introduce bias.
3351 static void perf_adjust_freq_unthr_context(struct perf_event_context
*ctx
,
3354 struct perf_event
*event
;
3355 struct hw_perf_event
*hwc
;
3356 u64 now
, period
= TICK_NSEC
;
3360 * only need to iterate over all events iff:
3361 * - context have events in frequency mode (needs freq adjust)
3362 * - there are events to unthrottle on this cpu
3364 if (!(ctx
->nr_freq
|| needs_unthr
))
3367 raw_spin_lock(&ctx
->lock
);
3368 perf_pmu_disable(ctx
->pmu
);
3370 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3371 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
3374 if (!event_filter_match(event
))
3377 perf_pmu_disable(event
->pmu
);
3381 if (hwc
->interrupts
== MAX_INTERRUPTS
) {
3382 hwc
->interrupts
= 0;
3383 perf_log_throttle(event
, 1);
3384 event
->pmu
->start(event
, 0);
3387 if (!event
->attr
.freq
|| !event
->attr
.sample_freq
)
3391 * stop the event and update event->count
3393 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
3395 now
= local64_read(&event
->count
);
3396 delta
= now
- hwc
->freq_count_stamp
;
3397 hwc
->freq_count_stamp
= now
;
3401 * reload only if value has changed
3402 * we have stopped the event so tell that
3403 * to perf_adjust_period() to avoid stopping it
3407 perf_adjust_period(event
, period
, delta
, false);
3409 event
->pmu
->start(event
, delta
> 0 ? PERF_EF_RELOAD
: 0);
3411 perf_pmu_enable(event
->pmu
);
3414 perf_pmu_enable(ctx
->pmu
);
3415 raw_spin_unlock(&ctx
->lock
);
3419 * Round-robin a context's events:
3421 static void rotate_ctx(struct perf_event_context
*ctx
)
3424 * Rotate the first entry last of non-pinned groups. Rotation might be
3425 * disabled by the inheritance code.
3427 if (!ctx
->rotate_disable
)
3428 list_rotate_left(&ctx
->flexible_groups
);
3431 static int perf_rotate_context(struct perf_cpu_context
*cpuctx
)
3433 struct perf_event_context
*ctx
= NULL
;
3436 if (cpuctx
->ctx
.nr_events
) {
3437 if (cpuctx
->ctx
.nr_events
!= cpuctx
->ctx
.nr_active
)
3441 ctx
= cpuctx
->task_ctx
;
3442 if (ctx
&& ctx
->nr_events
) {
3443 if (ctx
->nr_events
!= ctx
->nr_active
)
3450 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
3451 perf_pmu_disable(cpuctx
->ctx
.pmu
);
3453 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
3455 ctx_sched_out(ctx
, cpuctx
, EVENT_FLEXIBLE
);
3457 rotate_ctx(&cpuctx
->ctx
);
3461 perf_event_sched_in(cpuctx
, ctx
, current
);
3463 perf_pmu_enable(cpuctx
->ctx
.pmu
);
3464 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
3470 void perf_event_task_tick(void)
3472 struct list_head
*head
= this_cpu_ptr(&active_ctx_list
);
3473 struct perf_event_context
*ctx
, *tmp
;
3476 WARN_ON(!irqs_disabled());
3478 __this_cpu_inc(perf_throttled_seq
);
3479 throttled
= __this_cpu_xchg(perf_throttled_count
, 0);
3480 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS
);
3482 list_for_each_entry_safe(ctx
, tmp
, head
, active_ctx_list
)
3483 perf_adjust_freq_unthr_context(ctx
, throttled
);
3486 static int event_enable_on_exec(struct perf_event
*event
,
3487 struct perf_event_context
*ctx
)
3489 if (!event
->attr
.enable_on_exec
)
3492 event
->attr
.enable_on_exec
= 0;
3493 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
3496 __perf_event_mark_enabled(event
);
3502 * Enable all of a task's events that have been marked enable-on-exec.
3503 * This expects task == current.
3505 static void perf_event_enable_on_exec(int ctxn
)
3507 struct perf_event_context
*ctx
, *clone_ctx
= NULL
;
3508 enum event_type_t event_type
= 0;
3509 struct perf_cpu_context
*cpuctx
;
3510 struct perf_event
*event
;
3511 unsigned long flags
;
3514 local_irq_save(flags
);
3515 ctx
= current
->perf_event_ctxp
[ctxn
];
3516 if (!ctx
|| !ctx
->nr_events
)
3519 cpuctx
= __get_cpu_context(ctx
);
3520 perf_ctx_lock(cpuctx
, ctx
);
3521 ctx_sched_out(ctx
, cpuctx
, EVENT_TIME
);
3522 list_for_each_entry(event
, &ctx
->event_list
, event_entry
) {
3523 enabled
|= event_enable_on_exec(event
, ctx
);
3524 event_type
|= get_event_type(event
);
3528 * Unclone and reschedule this context if we enabled any event.
3531 clone_ctx
= unclone_ctx(ctx
);
3532 ctx_resched(cpuctx
, ctx
, event_type
);
3534 ctx_sched_in(ctx
, cpuctx
, EVENT_TIME
, current
);
3536 perf_ctx_unlock(cpuctx
, ctx
);
3539 local_irq_restore(flags
);
3545 struct perf_read_data
{
3546 struct perf_event
*event
;
3551 static int __perf_event_read_cpu(struct perf_event
*event
, int event_cpu
)
3553 u16 local_pkg
, event_pkg
;
3555 if (event
->group_caps
& PERF_EV_CAP_READ_ACTIVE_PKG
) {
3556 int local_cpu
= smp_processor_id();
3558 event_pkg
= topology_physical_package_id(event_cpu
);
3559 local_pkg
= topology_physical_package_id(local_cpu
);
3561 if (event_pkg
== local_pkg
)
3569 * Cross CPU call to read the hardware event
3571 static void __perf_event_read(void *info
)
3573 struct perf_read_data
*data
= info
;
3574 struct perf_event
*sub
, *event
= data
->event
;
3575 struct perf_event_context
*ctx
= event
->ctx
;
3576 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
3577 struct pmu
*pmu
= event
->pmu
;
3580 * If this is a task context, we need to check whether it is
3581 * the current task context of this cpu. If not it has been
3582 * scheduled out before the smp call arrived. In that case
3583 * event->count would have been updated to a recent sample
3584 * when the event was scheduled out.
3586 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
3589 raw_spin_lock(&ctx
->lock
);
3590 if (ctx
->is_active
) {
3591 update_context_time(ctx
);
3592 update_cgrp_time_from_event(event
);
3595 update_event_times(event
);
3596 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
3605 pmu
->start_txn(pmu
, PERF_PMU_TXN_READ
);
3609 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
3610 update_event_times(sub
);
3611 if (sub
->state
== PERF_EVENT_STATE_ACTIVE
) {
3613 * Use sibling's PMU rather than @event's since
3614 * sibling could be on different (eg: software) PMU.
3616 sub
->pmu
->read(sub
);
3620 data
->ret
= pmu
->commit_txn(pmu
);
3623 raw_spin_unlock(&ctx
->lock
);
3626 static inline u64
perf_event_count(struct perf_event
*event
)
3628 if (event
->pmu
->count
)
3629 return event
->pmu
->count(event
);
3631 return __perf_event_count(event
);
3635 * NMI-safe method to read a local event, that is an event that
3637 * - either for the current task, or for this CPU
3638 * - does not have inherit set, for inherited task events
3639 * will not be local and we cannot read them atomically
3640 * - must not have a pmu::count method
3642 u64
perf_event_read_local(struct perf_event
*event
)
3644 unsigned long flags
;
3648 * Disabling interrupts avoids all counter scheduling (context
3649 * switches, timer based rotation and IPIs).
3651 local_irq_save(flags
);
3653 /* If this is a per-task event, it must be for current */
3654 WARN_ON_ONCE((event
->attach_state
& PERF_ATTACH_TASK
) &&
3655 event
->hw
.target
!= current
);
3657 /* If this is a per-CPU event, it must be for this CPU */
3658 WARN_ON_ONCE(!(event
->attach_state
& PERF_ATTACH_TASK
) &&
3659 event
->cpu
!= smp_processor_id());
3662 * It must not be an event with inherit set, we cannot read
3663 * all child counters from atomic context.
3665 WARN_ON_ONCE(event
->attr
.inherit
);
3668 * It must not have a pmu::count method, those are not
3671 WARN_ON_ONCE(event
->pmu
->count
);
3674 * If the event is currently on this CPU, its either a per-task event,
3675 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3678 if (event
->oncpu
== smp_processor_id())
3679 event
->pmu
->read(event
);
3681 val
= local64_read(&event
->count
);
3682 local_irq_restore(flags
);
3687 static int perf_event_read(struct perf_event
*event
, bool group
)
3689 int event_cpu
, ret
= 0;
3692 * If event is enabled and currently active on a CPU, update the
3693 * value in the event structure:
3695 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
3696 struct perf_read_data data
= {
3702 event_cpu
= READ_ONCE(event
->oncpu
);
3703 if ((unsigned)event_cpu
>= nr_cpu_ids
)
3707 event_cpu
= __perf_event_read_cpu(event
, event_cpu
);
3710 * Purposely ignore the smp_call_function_single() return
3713 * If event_cpu isn't a valid CPU it means the event got
3714 * scheduled out and that will have updated the event count.
3716 * Therefore, either way, we'll have an up-to-date event count
3719 (void)smp_call_function_single(event_cpu
, __perf_event_read
, &data
, 1);
3722 } else if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
3723 struct perf_event_context
*ctx
= event
->ctx
;
3724 unsigned long flags
;
3726 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
3728 * may read while context is not active
3729 * (e.g., thread is blocked), in that case
3730 * we cannot update context time
3732 if (ctx
->is_active
) {
3733 update_context_time(ctx
);
3734 update_cgrp_time_from_event(event
);
3737 update_group_times(event
);
3739 update_event_times(event
);
3740 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
3747 * Initialize the perf_event context in a task_struct:
3749 static void __perf_event_init_context(struct perf_event_context
*ctx
)
3751 raw_spin_lock_init(&ctx
->lock
);
3752 mutex_init(&ctx
->mutex
);
3753 INIT_LIST_HEAD(&ctx
->active_ctx_list
);
3754 INIT_LIST_HEAD(&ctx
->pinned_groups
);
3755 INIT_LIST_HEAD(&ctx
->flexible_groups
);
3756 INIT_LIST_HEAD(&ctx
->event_list
);
3757 atomic_set(&ctx
->refcount
, 1);
3760 static struct perf_event_context
*
3761 alloc_perf_context(struct pmu
*pmu
, struct task_struct
*task
)
3763 struct perf_event_context
*ctx
;
3765 ctx
= kzalloc(sizeof(struct perf_event_context
), GFP_KERNEL
);
3769 __perf_event_init_context(ctx
);
3772 get_task_struct(task
);
3779 static struct task_struct
*
3780 find_lively_task_by_vpid(pid_t vpid
)
3782 struct task_struct
*task
;
3788 task
= find_task_by_vpid(vpid
);
3790 get_task_struct(task
);
3794 return ERR_PTR(-ESRCH
);
3800 * Returns a matching context with refcount and pincount.
3802 static struct perf_event_context
*
3803 find_get_context(struct pmu
*pmu
, struct task_struct
*task
,
3804 struct perf_event
*event
)
3806 struct perf_event_context
*ctx
, *clone_ctx
= NULL
;
3807 struct perf_cpu_context
*cpuctx
;
3808 void *task_ctx_data
= NULL
;
3809 unsigned long flags
;
3811 int cpu
= event
->cpu
;
3814 /* Must be root to operate on a CPU event: */
3815 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN
))
3816 return ERR_PTR(-EACCES
);
3818 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
3827 ctxn
= pmu
->task_ctx_nr
;
3831 if (event
->attach_state
& PERF_ATTACH_TASK_DATA
) {
3832 task_ctx_data
= kzalloc(pmu
->task_ctx_size
, GFP_KERNEL
);
3833 if (!task_ctx_data
) {
3840 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
3842 clone_ctx
= unclone_ctx(ctx
);
3845 if (task_ctx_data
&& !ctx
->task_ctx_data
) {
3846 ctx
->task_ctx_data
= task_ctx_data
;
3847 task_ctx_data
= NULL
;
3849 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
3854 ctx
= alloc_perf_context(pmu
, task
);
3859 if (task_ctx_data
) {
3860 ctx
->task_ctx_data
= task_ctx_data
;
3861 task_ctx_data
= NULL
;
3865 mutex_lock(&task
->perf_event_mutex
);
3867 * If it has already passed perf_event_exit_task().
3868 * we must see PF_EXITING, it takes this mutex too.
3870 if (task
->flags
& PF_EXITING
)
3872 else if (task
->perf_event_ctxp
[ctxn
])
3877 rcu_assign_pointer(task
->perf_event_ctxp
[ctxn
], ctx
);
3879 mutex_unlock(&task
->perf_event_mutex
);
3881 if (unlikely(err
)) {
3890 kfree(task_ctx_data
);
3894 kfree(task_ctx_data
);
3895 return ERR_PTR(err
);
3898 static void perf_event_free_filter(struct perf_event
*event
);
3899 static void perf_event_free_bpf_prog(struct perf_event
*event
);
3901 static void free_event_rcu(struct rcu_head
*head
)
3903 struct perf_event
*event
;
3905 event
= container_of(head
, struct perf_event
, rcu_head
);
3907 put_pid_ns(event
->ns
);
3908 perf_event_free_filter(event
);
3912 static void ring_buffer_attach(struct perf_event
*event
,
3913 struct ring_buffer
*rb
);
3915 static void detach_sb_event(struct perf_event
*event
)
3917 struct pmu_event_list
*pel
= per_cpu_ptr(&pmu_sb_events
, event
->cpu
);
3919 raw_spin_lock(&pel
->lock
);
3920 list_del_rcu(&event
->sb_list
);
3921 raw_spin_unlock(&pel
->lock
);
3924 static bool is_sb_event(struct perf_event
*event
)
3926 struct perf_event_attr
*attr
= &event
->attr
;
3931 if (event
->attach_state
& PERF_ATTACH_TASK
)
3934 if (attr
->mmap
|| attr
->mmap_data
|| attr
->mmap2
||
3935 attr
->comm
|| attr
->comm_exec
||
3937 attr
->context_switch
)
3942 static void unaccount_pmu_sb_event(struct perf_event
*event
)
3944 if (is_sb_event(event
))
3945 detach_sb_event(event
);
3948 static void unaccount_event_cpu(struct perf_event
*event
, int cpu
)
3953 if (is_cgroup_event(event
))
3954 atomic_dec(&per_cpu(perf_cgroup_events
, cpu
));
3957 #ifdef CONFIG_NO_HZ_FULL
3958 static DEFINE_SPINLOCK(nr_freq_lock
);
3961 static void unaccount_freq_event_nohz(void)
3963 #ifdef CONFIG_NO_HZ_FULL
3964 spin_lock(&nr_freq_lock
);
3965 if (atomic_dec_and_test(&nr_freq_events
))
3966 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS
);
3967 spin_unlock(&nr_freq_lock
);
3971 static void unaccount_freq_event(void)
3973 if (tick_nohz_full_enabled())
3974 unaccount_freq_event_nohz();
3976 atomic_dec(&nr_freq_events
);
3979 static void unaccount_event(struct perf_event
*event
)
3986 if (event
->attach_state
& PERF_ATTACH_TASK
)
3988 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
3989 atomic_dec(&nr_mmap_events
);
3990 if (event
->attr
.comm
)
3991 atomic_dec(&nr_comm_events
);
3992 if (event
->attr
.namespaces
)
3993 atomic_dec(&nr_namespaces_events
);
3994 if (event
->attr
.task
)
3995 atomic_dec(&nr_task_events
);
3996 if (event
->attr
.freq
)
3997 unaccount_freq_event();
3998 if (event
->attr
.context_switch
) {
4000 atomic_dec(&nr_switch_events
);
4002 if (is_cgroup_event(event
))
4004 if (has_branch_stack(event
))
4008 if (!atomic_add_unless(&perf_sched_count
, -1, 1))
4009 schedule_delayed_work(&perf_sched_work
, HZ
);
4012 unaccount_event_cpu(event
, event
->cpu
);
4014 unaccount_pmu_sb_event(event
);
4017 static void perf_sched_delayed(struct work_struct
*work
)
4019 mutex_lock(&perf_sched_mutex
);
4020 if (atomic_dec_and_test(&perf_sched_count
))
4021 static_branch_disable(&perf_sched_events
);
4022 mutex_unlock(&perf_sched_mutex
);
4026 * The following implement mutual exclusion of events on "exclusive" pmus
4027 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4028 * at a time, so we disallow creating events that might conflict, namely:
4030 * 1) cpu-wide events in the presence of per-task events,
4031 * 2) per-task events in the presence of cpu-wide events,
4032 * 3) two matching events on the same context.
4034 * The former two cases are handled in the allocation path (perf_event_alloc(),
4035 * _free_event()), the latter -- before the first perf_install_in_context().
4037 static int exclusive_event_init(struct perf_event
*event
)
4039 struct pmu
*pmu
= event
->pmu
;
4041 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
4045 * Prevent co-existence of per-task and cpu-wide events on the
4046 * same exclusive pmu.
4048 * Negative pmu::exclusive_cnt means there are cpu-wide
4049 * events on this "exclusive" pmu, positive means there are
4052 * Since this is called in perf_event_alloc() path, event::ctx
4053 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4054 * to mean "per-task event", because unlike other attach states it
4055 * never gets cleared.
4057 if (event
->attach_state
& PERF_ATTACH_TASK
) {
4058 if (!atomic_inc_unless_negative(&pmu
->exclusive_cnt
))
4061 if (!atomic_dec_unless_positive(&pmu
->exclusive_cnt
))
4068 static void exclusive_event_destroy(struct perf_event
*event
)
4070 struct pmu
*pmu
= event
->pmu
;
4072 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
4075 /* see comment in exclusive_event_init() */
4076 if (event
->attach_state
& PERF_ATTACH_TASK
)
4077 atomic_dec(&pmu
->exclusive_cnt
);
4079 atomic_inc(&pmu
->exclusive_cnt
);
4082 static bool exclusive_event_match(struct perf_event
*e1
, struct perf_event
*e2
)
4084 if ((e1
->pmu
== e2
->pmu
) &&
4085 (e1
->cpu
== e2
->cpu
||
4092 /* Called under the same ctx::mutex as perf_install_in_context() */
4093 static bool exclusive_event_installable(struct perf_event
*event
,
4094 struct perf_event_context
*ctx
)
4096 struct perf_event
*iter_event
;
4097 struct pmu
*pmu
= event
->pmu
;
4099 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
4102 list_for_each_entry(iter_event
, &ctx
->event_list
, event_entry
) {
4103 if (exclusive_event_match(iter_event
, event
))
4110 static void perf_addr_filters_splice(struct perf_event
*event
,
4111 struct list_head
*head
);
4113 static void _free_event(struct perf_event
*event
)
4115 irq_work_sync(&event
->pending
);
4117 unaccount_event(event
);
4121 * Can happen when we close an event with re-directed output.
4123 * Since we have a 0 refcount, perf_mmap_close() will skip
4124 * over us; possibly making our ring_buffer_put() the last.
4126 mutex_lock(&event
->mmap_mutex
);
4127 ring_buffer_attach(event
, NULL
);
4128 mutex_unlock(&event
->mmap_mutex
);
4131 if (is_cgroup_event(event
))
4132 perf_detach_cgroup(event
);
4134 if (!event
->parent
) {
4135 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
)
4136 put_callchain_buffers();
4139 perf_event_free_bpf_prog(event
);
4140 perf_addr_filters_splice(event
, NULL
);
4141 kfree(event
->addr_filters_offs
);
4144 event
->destroy(event
);
4147 put_ctx(event
->ctx
);
4149 exclusive_event_destroy(event
);
4150 module_put(event
->pmu
->module
);
4152 call_rcu(&event
->rcu_head
, free_event_rcu
);
4156 * Used to free events which have a known refcount of 1, such as in error paths
4157 * where the event isn't exposed yet and inherited events.
4159 static void free_event(struct perf_event
*event
)
4161 if (WARN(atomic_long_cmpxchg(&event
->refcount
, 1, 0) != 1,
4162 "unexpected event refcount: %ld; ptr=%p\n",
4163 atomic_long_read(&event
->refcount
), event
)) {
4164 /* leak to avoid use-after-free */
4172 * Remove user event from the owner task.
4174 static void perf_remove_from_owner(struct perf_event
*event
)
4176 struct task_struct
*owner
;
4180 * Matches the smp_store_release() in perf_event_exit_task(). If we
4181 * observe !owner it means the list deletion is complete and we can
4182 * indeed free this event, otherwise we need to serialize on
4183 * owner->perf_event_mutex.
4185 owner
= lockless_dereference(event
->owner
);
4188 * Since delayed_put_task_struct() also drops the last
4189 * task reference we can safely take a new reference
4190 * while holding the rcu_read_lock().
4192 get_task_struct(owner
);
4198 * If we're here through perf_event_exit_task() we're already
4199 * holding ctx->mutex which would be an inversion wrt. the
4200 * normal lock order.
4202 * However we can safely take this lock because its the child
4205 mutex_lock_nested(&owner
->perf_event_mutex
, SINGLE_DEPTH_NESTING
);
4208 * We have to re-check the event->owner field, if it is cleared
4209 * we raced with perf_event_exit_task(), acquiring the mutex
4210 * ensured they're done, and we can proceed with freeing the
4214 list_del_init(&event
->owner_entry
);
4215 smp_store_release(&event
->owner
, NULL
);
4217 mutex_unlock(&owner
->perf_event_mutex
);
4218 put_task_struct(owner
);
4222 static void put_event(struct perf_event
*event
)
4224 if (!atomic_long_dec_and_test(&event
->refcount
))
4231 * Kill an event dead; while event:refcount will preserve the event
4232 * object, it will not preserve its functionality. Once the last 'user'
4233 * gives up the object, we'll destroy the thing.
4235 int perf_event_release_kernel(struct perf_event
*event
)
4237 struct perf_event_context
*ctx
= event
->ctx
;
4238 struct perf_event
*child
, *tmp
;
4241 * If we got here through err_file: fput(event_file); we will not have
4242 * attached to a context yet.
4245 WARN_ON_ONCE(event
->attach_state
&
4246 (PERF_ATTACH_CONTEXT
|PERF_ATTACH_GROUP
));
4250 if (!is_kernel_event(event
))
4251 perf_remove_from_owner(event
);
4253 ctx
= perf_event_ctx_lock(event
);
4254 WARN_ON_ONCE(ctx
->parent_ctx
);
4255 perf_remove_from_context(event
, DETACH_GROUP
);
4257 raw_spin_lock_irq(&ctx
->lock
);
4259 * Mark this event as STATE_DEAD, there is no external reference to it
4262 * Anybody acquiring event->child_mutex after the below loop _must_
4263 * also see this, most importantly inherit_event() which will avoid
4264 * placing more children on the list.
4266 * Thus this guarantees that we will in fact observe and kill _ALL_
4269 event
->state
= PERF_EVENT_STATE_DEAD
;
4270 raw_spin_unlock_irq(&ctx
->lock
);
4272 perf_event_ctx_unlock(event
, ctx
);
4275 mutex_lock(&event
->child_mutex
);
4276 list_for_each_entry(child
, &event
->child_list
, child_list
) {
4279 * Cannot change, child events are not migrated, see the
4280 * comment with perf_event_ctx_lock_nested().
4282 ctx
= lockless_dereference(child
->ctx
);
4284 * Since child_mutex nests inside ctx::mutex, we must jump
4285 * through hoops. We start by grabbing a reference on the ctx.
4287 * Since the event cannot get freed while we hold the
4288 * child_mutex, the context must also exist and have a !0
4294 * Now that we have a ctx ref, we can drop child_mutex, and
4295 * acquire ctx::mutex without fear of it going away. Then we
4296 * can re-acquire child_mutex.
4298 mutex_unlock(&event
->child_mutex
);
4299 mutex_lock(&ctx
->mutex
);
4300 mutex_lock(&event
->child_mutex
);
4303 * Now that we hold ctx::mutex and child_mutex, revalidate our
4304 * state, if child is still the first entry, it didn't get freed
4305 * and we can continue doing so.
4307 tmp
= list_first_entry_or_null(&event
->child_list
,
4308 struct perf_event
, child_list
);
4310 perf_remove_from_context(child
, DETACH_GROUP
);
4311 list_del(&child
->child_list
);
4314 * This matches the refcount bump in inherit_event();
4315 * this can't be the last reference.
4320 mutex_unlock(&event
->child_mutex
);
4321 mutex_unlock(&ctx
->mutex
);
4325 mutex_unlock(&event
->child_mutex
);
4328 put_event(event
); /* Must be the 'last' reference */
4331 EXPORT_SYMBOL_GPL(perf_event_release_kernel
);
4334 * Called when the last reference to the file is gone.
4336 static int perf_release(struct inode
*inode
, struct file
*file
)
4338 perf_event_release_kernel(file
->private_data
);
4342 u64
perf_event_read_value(struct perf_event
*event
, u64
*enabled
, u64
*running
)
4344 struct perf_event
*child
;
4350 mutex_lock(&event
->child_mutex
);
4352 (void)perf_event_read(event
, false);
4353 total
+= perf_event_count(event
);
4355 *enabled
+= event
->total_time_enabled
+
4356 atomic64_read(&event
->child_total_time_enabled
);
4357 *running
+= event
->total_time_running
+
4358 atomic64_read(&event
->child_total_time_running
);
4360 list_for_each_entry(child
, &event
->child_list
, child_list
) {
4361 (void)perf_event_read(child
, false);
4362 total
+= perf_event_count(child
);
4363 *enabled
+= child
->total_time_enabled
;
4364 *running
+= child
->total_time_running
;
4366 mutex_unlock(&event
->child_mutex
);
4370 EXPORT_SYMBOL_GPL(perf_event_read_value
);
4372 static int __perf_read_group_add(struct perf_event
*leader
,
4373 u64 read_format
, u64
*values
)
4375 struct perf_event_context
*ctx
= leader
->ctx
;
4376 struct perf_event
*sub
;
4377 unsigned long flags
;
4378 int n
= 1; /* skip @nr */
4381 ret
= perf_event_read(leader
, true);
4386 * Since we co-schedule groups, {enabled,running} times of siblings
4387 * will be identical to those of the leader, so we only publish one
4390 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
4391 values
[n
++] += leader
->total_time_enabled
+
4392 atomic64_read(&leader
->child_total_time_enabled
);
4395 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
4396 values
[n
++] += leader
->total_time_running
+
4397 atomic64_read(&leader
->child_total_time_running
);
4401 * Write {count,id} tuples for every sibling.
4403 values
[n
++] += perf_event_count(leader
);
4404 if (read_format
& PERF_FORMAT_ID
)
4405 values
[n
++] = primary_event_id(leader
);
4407 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
4409 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
4410 values
[n
++] += perf_event_count(sub
);
4411 if (read_format
& PERF_FORMAT_ID
)
4412 values
[n
++] = primary_event_id(sub
);
4415 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
4419 static int perf_read_group(struct perf_event
*event
,
4420 u64 read_format
, char __user
*buf
)
4422 struct perf_event
*leader
= event
->group_leader
, *child
;
4423 struct perf_event_context
*ctx
= leader
->ctx
;
4427 lockdep_assert_held(&ctx
->mutex
);
4429 values
= kzalloc(event
->read_size
, GFP_KERNEL
);
4433 values
[0] = 1 + leader
->nr_siblings
;
4436 * By locking the child_mutex of the leader we effectively
4437 * lock the child list of all siblings.. XXX explain how.
4439 mutex_lock(&leader
->child_mutex
);
4441 ret
= __perf_read_group_add(leader
, read_format
, values
);
4445 list_for_each_entry(child
, &leader
->child_list
, child_list
) {
4446 ret
= __perf_read_group_add(child
, read_format
, values
);
4451 mutex_unlock(&leader
->child_mutex
);
4453 ret
= event
->read_size
;
4454 if (copy_to_user(buf
, values
, event
->read_size
))
4459 mutex_unlock(&leader
->child_mutex
);
4465 static int perf_read_one(struct perf_event
*event
,
4466 u64 read_format
, char __user
*buf
)
4468 u64 enabled
, running
;
4472 values
[n
++] = perf_event_read_value(event
, &enabled
, &running
);
4473 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
4474 values
[n
++] = enabled
;
4475 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
4476 values
[n
++] = running
;
4477 if (read_format
& PERF_FORMAT_ID
)
4478 values
[n
++] = primary_event_id(event
);
4480 if (copy_to_user(buf
, values
, n
* sizeof(u64
)))
4483 return n
* sizeof(u64
);
4486 static bool is_event_hup(struct perf_event
*event
)
4490 if (event
->state
> PERF_EVENT_STATE_EXIT
)
4493 mutex_lock(&event
->child_mutex
);
4494 no_children
= list_empty(&event
->child_list
);
4495 mutex_unlock(&event
->child_mutex
);
4500 * Read the performance event - simple non blocking version for now
4503 __perf_read(struct perf_event
*event
, char __user
*buf
, size_t count
)
4505 u64 read_format
= event
->attr
.read_format
;
4509 * Return end-of-file for a read on a event that is in
4510 * error state (i.e. because it was pinned but it couldn't be
4511 * scheduled on to the CPU at some point).
4513 if (event
->state
== PERF_EVENT_STATE_ERROR
)
4516 if (count
< event
->read_size
)
4519 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
4520 if (read_format
& PERF_FORMAT_GROUP
)
4521 ret
= perf_read_group(event
, read_format
, buf
);
4523 ret
= perf_read_one(event
, read_format
, buf
);
4529 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
4531 struct perf_event
*event
= file
->private_data
;
4532 struct perf_event_context
*ctx
;
4535 ctx
= perf_event_ctx_lock(event
);
4536 ret
= __perf_read(event
, buf
, count
);
4537 perf_event_ctx_unlock(event
, ctx
);
4542 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
4544 struct perf_event
*event
= file
->private_data
;
4545 struct ring_buffer
*rb
;
4546 unsigned int events
= POLLHUP
;
4548 poll_wait(file
, &event
->waitq
, wait
);
4550 if (is_event_hup(event
))
4554 * Pin the event->rb by taking event->mmap_mutex; otherwise
4555 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4557 mutex_lock(&event
->mmap_mutex
);
4560 events
= atomic_xchg(&rb
->poll
, 0);
4561 mutex_unlock(&event
->mmap_mutex
);
4565 static void _perf_event_reset(struct perf_event
*event
)
4567 (void)perf_event_read(event
, false);
4568 local64_set(&event
->count
, 0);
4569 perf_event_update_userpage(event
);
4573 * Holding the top-level event's child_mutex means that any
4574 * descendant process that has inherited this event will block
4575 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4576 * task existence requirements of perf_event_enable/disable.
4578 static void perf_event_for_each_child(struct perf_event
*event
,
4579 void (*func
)(struct perf_event
*))
4581 struct perf_event
*child
;
4583 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
4585 mutex_lock(&event
->child_mutex
);
4587 list_for_each_entry(child
, &event
->child_list
, child_list
)
4589 mutex_unlock(&event
->child_mutex
);
4592 static void perf_event_for_each(struct perf_event
*event
,
4593 void (*func
)(struct perf_event
*))
4595 struct perf_event_context
*ctx
= event
->ctx
;
4596 struct perf_event
*sibling
;
4598 lockdep_assert_held(&ctx
->mutex
);
4600 event
= event
->group_leader
;
4602 perf_event_for_each_child(event
, func
);
4603 list_for_each_entry(sibling
, &event
->sibling_list
, group_entry
)
4604 perf_event_for_each_child(sibling
, func
);
4607 static void __perf_event_period(struct perf_event
*event
,
4608 struct perf_cpu_context
*cpuctx
,
4609 struct perf_event_context
*ctx
,
4612 u64 value
= *((u64
*)info
);
4615 if (event
->attr
.freq
) {
4616 event
->attr
.sample_freq
= value
;
4618 event
->attr
.sample_period
= value
;
4619 event
->hw
.sample_period
= value
;
4622 active
= (event
->state
== PERF_EVENT_STATE_ACTIVE
);
4624 perf_pmu_disable(ctx
->pmu
);
4626 * We could be throttled; unthrottle now to avoid the tick
4627 * trying to unthrottle while we already re-started the event.
4629 if (event
->hw
.interrupts
== MAX_INTERRUPTS
) {
4630 event
->hw
.interrupts
= 0;
4631 perf_log_throttle(event
, 1);
4633 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
4636 local64_set(&event
->hw
.period_left
, 0);
4639 event
->pmu
->start(event
, PERF_EF_RELOAD
);
4640 perf_pmu_enable(ctx
->pmu
);
4644 static int perf_event_period(struct perf_event
*event
, u64 __user
*arg
)
4648 if (!is_sampling_event(event
))
4651 if (copy_from_user(&value
, arg
, sizeof(value
)))
4657 if (event
->attr
.freq
&& value
> sysctl_perf_event_sample_rate
)
4660 event_function_call(event
, __perf_event_period
, &value
);
4665 static const struct file_operations perf_fops
;
4667 static inline int perf_fget_light(int fd
, struct fd
*p
)
4669 struct fd f
= fdget(fd
);
4673 if (f
.file
->f_op
!= &perf_fops
) {
4681 static int perf_event_set_output(struct perf_event
*event
,
4682 struct perf_event
*output_event
);
4683 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
);
4684 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
);
4686 static long _perf_ioctl(struct perf_event
*event
, unsigned int cmd
, unsigned long arg
)
4688 void (*func
)(struct perf_event
*);
4692 case PERF_EVENT_IOC_ENABLE
:
4693 func
= _perf_event_enable
;
4695 case PERF_EVENT_IOC_DISABLE
:
4696 func
= _perf_event_disable
;
4698 case PERF_EVENT_IOC_RESET
:
4699 func
= _perf_event_reset
;
4702 case PERF_EVENT_IOC_REFRESH
:
4703 return _perf_event_refresh(event
, arg
);
4705 case PERF_EVENT_IOC_PERIOD
:
4706 return perf_event_period(event
, (u64 __user
*)arg
);
4708 case PERF_EVENT_IOC_ID
:
4710 u64 id
= primary_event_id(event
);
4712 if (copy_to_user((void __user
*)arg
, &id
, sizeof(id
)))
4717 case PERF_EVENT_IOC_SET_OUTPUT
:
4721 struct perf_event
*output_event
;
4723 ret
= perf_fget_light(arg
, &output
);
4726 output_event
= output
.file
->private_data
;
4727 ret
= perf_event_set_output(event
, output_event
);
4730 ret
= perf_event_set_output(event
, NULL
);
4735 case PERF_EVENT_IOC_SET_FILTER
:
4736 return perf_event_set_filter(event
, (void __user
*)arg
);
4738 case PERF_EVENT_IOC_SET_BPF
:
4739 return perf_event_set_bpf_prog(event
, arg
);
4741 case PERF_EVENT_IOC_PAUSE_OUTPUT
: {
4742 struct ring_buffer
*rb
;
4745 rb
= rcu_dereference(event
->rb
);
4746 if (!rb
|| !rb
->nr_pages
) {
4750 rb_toggle_paused(rb
, !!arg
);
4758 if (flags
& PERF_IOC_FLAG_GROUP
)
4759 perf_event_for_each(event
, func
);
4761 perf_event_for_each_child(event
, func
);
4766 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
4768 struct perf_event
*event
= file
->private_data
;
4769 struct perf_event_context
*ctx
;
4772 ctx
= perf_event_ctx_lock(event
);
4773 ret
= _perf_ioctl(event
, cmd
, arg
);
4774 perf_event_ctx_unlock(event
, ctx
);
4779 #ifdef CONFIG_COMPAT
4780 static long perf_compat_ioctl(struct file
*file
, unsigned int cmd
,
4783 switch (_IOC_NR(cmd
)) {
4784 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER
):
4785 case _IOC_NR(PERF_EVENT_IOC_ID
):
4786 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4787 if (_IOC_SIZE(cmd
) == sizeof(compat_uptr_t
)) {
4788 cmd
&= ~IOCSIZE_MASK
;
4789 cmd
|= sizeof(void *) << IOCSIZE_SHIFT
;
4793 return perf_ioctl(file
, cmd
, arg
);
4796 # define perf_compat_ioctl NULL
4799 int perf_event_task_enable(void)
4801 struct perf_event_context
*ctx
;
4802 struct perf_event
*event
;
4804 mutex_lock(¤t
->perf_event_mutex
);
4805 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
) {
4806 ctx
= perf_event_ctx_lock(event
);
4807 perf_event_for_each_child(event
, _perf_event_enable
);
4808 perf_event_ctx_unlock(event
, ctx
);
4810 mutex_unlock(¤t
->perf_event_mutex
);
4815 int perf_event_task_disable(void)
4817 struct perf_event_context
*ctx
;
4818 struct perf_event
*event
;
4820 mutex_lock(¤t
->perf_event_mutex
);
4821 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
) {
4822 ctx
= perf_event_ctx_lock(event
);
4823 perf_event_for_each_child(event
, _perf_event_disable
);
4824 perf_event_ctx_unlock(event
, ctx
);
4826 mutex_unlock(¤t
->perf_event_mutex
);
4831 static int perf_event_index(struct perf_event
*event
)
4833 if (event
->hw
.state
& PERF_HES_STOPPED
)
4836 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
4839 return event
->pmu
->event_idx(event
);
4842 static void calc_timer_values(struct perf_event
*event
,
4849 *now
= perf_clock();
4850 ctx_time
= event
->shadow_ctx_time
+ *now
;
4851 *enabled
= ctx_time
- event
->tstamp_enabled
;
4852 *running
= ctx_time
- event
->tstamp_running
;
4855 static void perf_event_init_userpage(struct perf_event
*event
)
4857 struct perf_event_mmap_page
*userpg
;
4858 struct ring_buffer
*rb
;
4861 rb
= rcu_dereference(event
->rb
);
4865 userpg
= rb
->user_page
;
4867 /* Allow new userspace to detect that bit 0 is deprecated */
4868 userpg
->cap_bit0_is_deprecated
= 1;
4869 userpg
->size
= offsetof(struct perf_event_mmap_page
, __reserved
);
4870 userpg
->data_offset
= PAGE_SIZE
;
4871 userpg
->data_size
= perf_data_size(rb
);
4877 void __weak
arch_perf_update_userpage(
4878 struct perf_event
*event
, struct perf_event_mmap_page
*userpg
, u64 now
)
4883 * Callers need to ensure there can be no nesting of this function, otherwise
4884 * the seqlock logic goes bad. We can not serialize this because the arch
4885 * code calls this from NMI context.
4887 void perf_event_update_userpage(struct perf_event
*event
)
4889 struct perf_event_mmap_page
*userpg
;
4890 struct ring_buffer
*rb
;
4891 u64 enabled
, running
, now
;
4894 rb
= rcu_dereference(event
->rb
);
4899 * compute total_time_enabled, total_time_running
4900 * based on snapshot values taken when the event
4901 * was last scheduled in.
4903 * we cannot simply called update_context_time()
4904 * because of locking issue as we can be called in
4907 calc_timer_values(event
, &now
, &enabled
, &running
);
4909 userpg
= rb
->user_page
;
4911 * Disable preemption so as to not let the corresponding user-space
4912 * spin too long if we get preempted.
4917 userpg
->index
= perf_event_index(event
);
4918 userpg
->offset
= perf_event_count(event
);
4920 userpg
->offset
-= local64_read(&event
->hw
.prev_count
);
4922 userpg
->time_enabled
= enabled
+
4923 atomic64_read(&event
->child_total_time_enabled
);
4925 userpg
->time_running
= running
+
4926 atomic64_read(&event
->child_total_time_running
);
4928 arch_perf_update_userpage(event
, userpg
, now
);
4937 static int perf_mmap_fault(struct vm_fault
*vmf
)
4939 struct perf_event
*event
= vmf
->vma
->vm_file
->private_data
;
4940 struct ring_buffer
*rb
;
4941 int ret
= VM_FAULT_SIGBUS
;
4943 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
4944 if (vmf
->pgoff
== 0)
4950 rb
= rcu_dereference(event
->rb
);
4954 if (vmf
->pgoff
&& (vmf
->flags
& FAULT_FLAG_WRITE
))
4957 vmf
->page
= perf_mmap_to_page(rb
, vmf
->pgoff
);
4961 get_page(vmf
->page
);
4962 vmf
->page
->mapping
= vmf
->vma
->vm_file
->f_mapping
;
4963 vmf
->page
->index
= vmf
->pgoff
;
4972 static void ring_buffer_attach(struct perf_event
*event
,
4973 struct ring_buffer
*rb
)
4975 struct ring_buffer
*old_rb
= NULL
;
4976 unsigned long flags
;
4980 * Should be impossible, we set this when removing
4981 * event->rb_entry and wait/clear when adding event->rb_entry.
4983 WARN_ON_ONCE(event
->rcu_pending
);
4986 spin_lock_irqsave(&old_rb
->event_lock
, flags
);
4987 list_del_rcu(&event
->rb_entry
);
4988 spin_unlock_irqrestore(&old_rb
->event_lock
, flags
);
4990 event
->rcu_batches
= get_state_synchronize_rcu();
4991 event
->rcu_pending
= 1;
4995 if (event
->rcu_pending
) {
4996 cond_synchronize_rcu(event
->rcu_batches
);
4997 event
->rcu_pending
= 0;
5000 spin_lock_irqsave(&rb
->event_lock
, flags
);
5001 list_add_rcu(&event
->rb_entry
, &rb
->event_list
);
5002 spin_unlock_irqrestore(&rb
->event_lock
, flags
);
5006 * Avoid racing with perf_mmap_close(AUX): stop the event
5007 * before swizzling the event::rb pointer; if it's getting
5008 * unmapped, its aux_mmap_count will be 0 and it won't
5009 * restart. See the comment in __perf_pmu_output_stop().
5011 * Data will inevitably be lost when set_output is done in
5012 * mid-air, but then again, whoever does it like this is
5013 * not in for the data anyway.
5016 perf_event_stop(event
, 0);
5018 rcu_assign_pointer(event
->rb
, rb
);
5021 ring_buffer_put(old_rb
);
5023 * Since we detached before setting the new rb, so that we
5024 * could attach the new rb, we could have missed a wakeup.
5027 wake_up_all(&event
->waitq
);
5031 static void ring_buffer_wakeup(struct perf_event
*event
)
5033 struct ring_buffer
*rb
;
5036 rb
= rcu_dereference(event
->rb
);
5038 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
)
5039 wake_up_all(&event
->waitq
);
5044 struct ring_buffer
*ring_buffer_get(struct perf_event
*event
)
5046 struct ring_buffer
*rb
;
5049 rb
= rcu_dereference(event
->rb
);
5051 if (!atomic_inc_not_zero(&rb
->refcount
))
5059 void ring_buffer_put(struct ring_buffer
*rb
)
5061 if (!atomic_dec_and_test(&rb
->refcount
))
5064 WARN_ON_ONCE(!list_empty(&rb
->event_list
));
5066 call_rcu(&rb
->rcu_head
, rb_free_rcu
);
5069 static void perf_mmap_open(struct vm_area_struct
*vma
)
5071 struct perf_event
*event
= vma
->vm_file
->private_data
;
5073 atomic_inc(&event
->mmap_count
);
5074 atomic_inc(&event
->rb
->mmap_count
);
5077 atomic_inc(&event
->rb
->aux_mmap_count
);
5079 if (event
->pmu
->event_mapped
)
5080 event
->pmu
->event_mapped(event
);
5083 static void perf_pmu_output_stop(struct perf_event
*event
);
5086 * A buffer can be mmap()ed multiple times; either directly through the same
5087 * event, or through other events by use of perf_event_set_output().
5089 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5090 * the buffer here, where we still have a VM context. This means we need
5091 * to detach all events redirecting to us.
5093 static void perf_mmap_close(struct vm_area_struct
*vma
)
5095 struct perf_event
*event
= vma
->vm_file
->private_data
;
5097 struct ring_buffer
*rb
= ring_buffer_get(event
);
5098 struct user_struct
*mmap_user
= rb
->mmap_user
;
5099 int mmap_locked
= rb
->mmap_locked
;
5100 unsigned long size
= perf_data_size(rb
);
5102 if (event
->pmu
->event_unmapped
)
5103 event
->pmu
->event_unmapped(event
);
5106 * rb->aux_mmap_count will always drop before rb->mmap_count and
5107 * event->mmap_count, so it is ok to use event->mmap_mutex to
5108 * serialize with perf_mmap here.
5110 if (rb_has_aux(rb
) && vma
->vm_pgoff
== rb
->aux_pgoff
&&
5111 atomic_dec_and_mutex_lock(&rb
->aux_mmap_count
, &event
->mmap_mutex
)) {
5113 * Stop all AUX events that are writing to this buffer,
5114 * so that we can free its AUX pages and corresponding PMU
5115 * data. Note that after rb::aux_mmap_count dropped to zero,
5116 * they won't start any more (see perf_aux_output_begin()).
5118 perf_pmu_output_stop(event
);
5120 /* now it's safe to free the pages */
5121 atomic_long_sub(rb
->aux_nr_pages
, &mmap_user
->locked_vm
);
5122 vma
->vm_mm
->pinned_vm
-= rb
->aux_mmap_locked
;
5124 /* this has to be the last one */
5126 WARN_ON_ONCE(atomic_read(&rb
->aux_refcount
));
5128 mutex_unlock(&event
->mmap_mutex
);
5131 atomic_dec(&rb
->mmap_count
);
5133 if (!atomic_dec_and_mutex_lock(&event
->mmap_count
, &event
->mmap_mutex
))
5136 ring_buffer_attach(event
, NULL
);
5137 mutex_unlock(&event
->mmap_mutex
);
5139 /* If there's still other mmap()s of this buffer, we're done. */
5140 if (atomic_read(&rb
->mmap_count
))
5144 * No other mmap()s, detach from all other events that might redirect
5145 * into the now unreachable buffer. Somewhat complicated by the
5146 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5150 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
) {
5151 if (!atomic_long_inc_not_zero(&event
->refcount
)) {
5153 * This event is en-route to free_event() which will
5154 * detach it and remove it from the list.
5160 mutex_lock(&event
->mmap_mutex
);
5162 * Check we didn't race with perf_event_set_output() which can
5163 * swizzle the rb from under us while we were waiting to
5164 * acquire mmap_mutex.
5166 * If we find a different rb; ignore this event, a next
5167 * iteration will no longer find it on the list. We have to
5168 * still restart the iteration to make sure we're not now
5169 * iterating the wrong list.
5171 if (event
->rb
== rb
)
5172 ring_buffer_attach(event
, NULL
);
5174 mutex_unlock(&event
->mmap_mutex
);
5178 * Restart the iteration; either we're on the wrong list or
5179 * destroyed its integrity by doing a deletion.
5186 * It could be there's still a few 0-ref events on the list; they'll
5187 * get cleaned up by free_event() -- they'll also still have their
5188 * ref on the rb and will free it whenever they are done with it.
5190 * Aside from that, this buffer is 'fully' detached and unmapped,
5191 * undo the VM accounting.
5194 atomic_long_sub((size
>> PAGE_SHIFT
) + 1, &mmap_user
->locked_vm
);
5195 vma
->vm_mm
->pinned_vm
-= mmap_locked
;
5196 free_uid(mmap_user
);
5199 ring_buffer_put(rb
); /* could be last */
5202 static const struct vm_operations_struct perf_mmap_vmops
= {
5203 .open
= perf_mmap_open
,
5204 .close
= perf_mmap_close
, /* non mergable */
5205 .fault
= perf_mmap_fault
,
5206 .page_mkwrite
= perf_mmap_fault
,
5209 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
5211 struct perf_event
*event
= file
->private_data
;
5212 unsigned long user_locked
, user_lock_limit
;
5213 struct user_struct
*user
= current_user();
5214 unsigned long locked
, lock_limit
;
5215 struct ring_buffer
*rb
= NULL
;
5216 unsigned long vma_size
;
5217 unsigned long nr_pages
;
5218 long user_extra
= 0, extra
= 0;
5219 int ret
= 0, flags
= 0;
5222 * Don't allow mmap() of inherited per-task counters. This would
5223 * create a performance issue due to all children writing to the
5226 if (event
->cpu
== -1 && event
->attr
.inherit
)
5229 if (!(vma
->vm_flags
& VM_SHARED
))
5232 vma_size
= vma
->vm_end
- vma
->vm_start
;
5234 if (vma
->vm_pgoff
== 0) {
5235 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
5238 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5239 * mapped, all subsequent mappings should have the same size
5240 * and offset. Must be above the normal perf buffer.
5242 u64 aux_offset
, aux_size
;
5247 nr_pages
= vma_size
/ PAGE_SIZE
;
5249 mutex_lock(&event
->mmap_mutex
);
5256 aux_offset
= ACCESS_ONCE(rb
->user_page
->aux_offset
);
5257 aux_size
= ACCESS_ONCE(rb
->user_page
->aux_size
);
5259 if (aux_offset
< perf_data_size(rb
) + PAGE_SIZE
)
5262 if (aux_offset
!= vma
->vm_pgoff
<< PAGE_SHIFT
)
5265 /* already mapped with a different offset */
5266 if (rb_has_aux(rb
) && rb
->aux_pgoff
!= vma
->vm_pgoff
)
5269 if (aux_size
!= vma_size
|| aux_size
!= nr_pages
* PAGE_SIZE
)
5272 /* already mapped with a different size */
5273 if (rb_has_aux(rb
) && rb
->aux_nr_pages
!= nr_pages
)
5276 if (!is_power_of_2(nr_pages
))
5279 if (!atomic_inc_not_zero(&rb
->mmap_count
))
5282 if (rb_has_aux(rb
)) {
5283 atomic_inc(&rb
->aux_mmap_count
);
5288 atomic_set(&rb
->aux_mmap_count
, 1);
5289 user_extra
= nr_pages
;
5295 * If we have rb pages ensure they're a power-of-two number, so we
5296 * can do bitmasks instead of modulo.
5298 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
5301 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
5304 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
5306 mutex_lock(&event
->mmap_mutex
);
5308 if (event
->rb
->nr_pages
!= nr_pages
) {
5313 if (!atomic_inc_not_zero(&event
->rb
->mmap_count
)) {
5315 * Raced against perf_mmap_close() through
5316 * perf_event_set_output(). Try again, hope for better
5319 mutex_unlock(&event
->mmap_mutex
);
5326 user_extra
= nr_pages
+ 1;
5329 user_lock_limit
= sysctl_perf_event_mlock
>> (PAGE_SHIFT
- 10);
5332 * Increase the limit linearly with more CPUs:
5334 user_lock_limit
*= num_online_cpus();
5336 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
5338 if (user_locked
> user_lock_limit
)
5339 extra
= user_locked
- user_lock_limit
;
5341 lock_limit
= rlimit(RLIMIT_MEMLOCK
);
5342 lock_limit
>>= PAGE_SHIFT
;
5343 locked
= vma
->vm_mm
->pinned_vm
+ extra
;
5345 if ((locked
> lock_limit
) && perf_paranoid_tracepoint_raw() &&
5346 !capable(CAP_IPC_LOCK
)) {
5351 WARN_ON(!rb
&& event
->rb
);
5353 if (vma
->vm_flags
& VM_WRITE
)
5354 flags
|= RING_BUFFER_WRITABLE
;
5357 rb
= rb_alloc(nr_pages
,
5358 event
->attr
.watermark
? event
->attr
.wakeup_watermark
: 0,
5366 atomic_set(&rb
->mmap_count
, 1);
5367 rb
->mmap_user
= get_current_user();
5368 rb
->mmap_locked
= extra
;
5370 ring_buffer_attach(event
, rb
);
5372 perf_event_init_userpage(event
);
5373 perf_event_update_userpage(event
);
5375 ret
= rb_alloc_aux(rb
, event
, vma
->vm_pgoff
, nr_pages
,
5376 event
->attr
.aux_watermark
, flags
);
5378 rb
->aux_mmap_locked
= extra
;
5383 atomic_long_add(user_extra
, &user
->locked_vm
);
5384 vma
->vm_mm
->pinned_vm
+= extra
;
5386 atomic_inc(&event
->mmap_count
);
5388 atomic_dec(&rb
->mmap_count
);
5391 mutex_unlock(&event
->mmap_mutex
);
5394 * Since pinned accounting is per vm we cannot allow fork() to copy our
5397 vma
->vm_flags
|= VM_DONTCOPY
| VM_DONTEXPAND
| VM_DONTDUMP
;
5398 vma
->vm_ops
= &perf_mmap_vmops
;
5400 if (event
->pmu
->event_mapped
)
5401 event
->pmu
->event_mapped(event
);
5406 static int perf_fasync(int fd
, struct file
*filp
, int on
)
5408 struct inode
*inode
= file_inode(filp
);
5409 struct perf_event
*event
= filp
->private_data
;
5413 retval
= fasync_helper(fd
, filp
, on
, &event
->fasync
);
5414 inode_unlock(inode
);
5422 static const struct file_operations perf_fops
= {
5423 .llseek
= no_llseek
,
5424 .release
= perf_release
,
5427 .unlocked_ioctl
= perf_ioctl
,
5428 .compat_ioctl
= perf_compat_ioctl
,
5430 .fasync
= perf_fasync
,
5436 * If there's data, ensure we set the poll() state and publish everything
5437 * to user-space before waking everybody up.
5440 static inline struct fasync_struct
**perf_event_fasync(struct perf_event
*event
)
5442 /* only the parent has fasync state */
5444 event
= event
->parent
;
5445 return &event
->fasync
;
5448 void perf_event_wakeup(struct perf_event
*event
)
5450 ring_buffer_wakeup(event
);
5452 if (event
->pending_kill
) {
5453 kill_fasync(perf_event_fasync(event
), SIGIO
, event
->pending_kill
);
5454 event
->pending_kill
= 0;
5458 static void perf_pending_event(struct irq_work
*entry
)
5460 struct perf_event
*event
= container_of(entry
,
5461 struct perf_event
, pending
);
5464 rctx
= perf_swevent_get_recursion_context();
5466 * If we 'fail' here, that's OK, it means recursion is already disabled
5467 * and we won't recurse 'further'.
5470 if (event
->pending_disable
) {
5471 event
->pending_disable
= 0;
5472 perf_event_disable_local(event
);
5475 if (event
->pending_wakeup
) {
5476 event
->pending_wakeup
= 0;
5477 perf_event_wakeup(event
);
5481 perf_swevent_put_recursion_context(rctx
);
5485 * We assume there is only KVM supporting the callbacks.
5486 * Later on, we might change it to a list if there is
5487 * another virtualization implementation supporting the callbacks.
5489 struct perf_guest_info_callbacks
*perf_guest_cbs
;
5491 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
5493 perf_guest_cbs
= cbs
;
5496 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks
);
5498 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
5500 perf_guest_cbs
= NULL
;
5503 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks
);
5506 perf_output_sample_regs(struct perf_output_handle
*handle
,
5507 struct pt_regs
*regs
, u64 mask
)
5510 DECLARE_BITMAP(_mask
, 64);
5512 bitmap_from_u64(_mask
, mask
);
5513 for_each_set_bit(bit
, _mask
, sizeof(mask
) * BITS_PER_BYTE
) {
5516 val
= perf_reg_value(regs
, bit
);
5517 perf_output_put(handle
, val
);
5521 static void perf_sample_regs_user(struct perf_regs
*regs_user
,
5522 struct pt_regs
*regs
,
5523 struct pt_regs
*regs_user_copy
)
5525 if (user_mode(regs
)) {
5526 regs_user
->abi
= perf_reg_abi(current
);
5527 regs_user
->regs
= regs
;
5528 } else if (current
->mm
) {
5529 perf_get_regs_user(regs_user
, regs
, regs_user_copy
);
5531 regs_user
->abi
= PERF_SAMPLE_REGS_ABI_NONE
;
5532 regs_user
->regs
= NULL
;
5536 static void perf_sample_regs_intr(struct perf_regs
*regs_intr
,
5537 struct pt_regs
*regs
)
5539 regs_intr
->regs
= regs
;
5540 regs_intr
->abi
= perf_reg_abi(current
);
5545 * Get remaining task size from user stack pointer.
5547 * It'd be better to take stack vma map and limit this more
5548 * precisly, but there's no way to get it safely under interrupt,
5549 * so using TASK_SIZE as limit.
5551 static u64
perf_ustack_task_size(struct pt_regs
*regs
)
5553 unsigned long addr
= perf_user_stack_pointer(regs
);
5555 if (!addr
|| addr
>= TASK_SIZE
)
5558 return TASK_SIZE
- addr
;
5562 perf_sample_ustack_size(u16 stack_size
, u16 header_size
,
5563 struct pt_regs
*regs
)
5567 /* No regs, no stack pointer, no dump. */
5572 * Check if we fit in with the requested stack size into the:
5574 * If we don't, we limit the size to the TASK_SIZE.
5576 * - remaining sample size
5577 * If we don't, we customize the stack size to
5578 * fit in to the remaining sample size.
5581 task_size
= min((u64
) USHRT_MAX
, perf_ustack_task_size(regs
));
5582 stack_size
= min(stack_size
, (u16
) task_size
);
5584 /* Current header size plus static size and dynamic size. */
5585 header_size
+= 2 * sizeof(u64
);
5587 /* Do we fit in with the current stack dump size? */
5588 if ((u16
) (header_size
+ stack_size
) < header_size
) {
5590 * If we overflow the maximum size for the sample,
5591 * we customize the stack dump size to fit in.
5593 stack_size
= USHRT_MAX
- header_size
- sizeof(u64
);
5594 stack_size
= round_up(stack_size
, sizeof(u64
));
5601 perf_output_sample_ustack(struct perf_output_handle
*handle
, u64 dump_size
,
5602 struct pt_regs
*regs
)
5604 /* Case of a kernel thread, nothing to dump */
5607 perf_output_put(handle
, size
);
5616 * - the size requested by user or the best one we can fit
5617 * in to the sample max size
5619 * - user stack dump data
5621 * - the actual dumped size
5625 perf_output_put(handle
, dump_size
);
5628 sp
= perf_user_stack_pointer(regs
);
5629 rem
= __output_copy_user(handle
, (void *) sp
, dump_size
);
5630 dyn_size
= dump_size
- rem
;
5632 perf_output_skip(handle
, rem
);
5635 perf_output_put(handle
, dyn_size
);
5639 static void __perf_event_header__init_id(struct perf_event_header
*header
,
5640 struct perf_sample_data
*data
,
5641 struct perf_event
*event
)
5643 u64 sample_type
= event
->attr
.sample_type
;
5645 data
->type
= sample_type
;
5646 header
->size
+= event
->id_header_size
;
5648 if (sample_type
& PERF_SAMPLE_TID
) {
5649 /* namespace issues */
5650 data
->tid_entry
.pid
= perf_event_pid(event
, current
);
5651 data
->tid_entry
.tid
= perf_event_tid(event
, current
);
5654 if (sample_type
& PERF_SAMPLE_TIME
)
5655 data
->time
= perf_event_clock(event
);
5657 if (sample_type
& (PERF_SAMPLE_ID
| PERF_SAMPLE_IDENTIFIER
))
5658 data
->id
= primary_event_id(event
);
5660 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
5661 data
->stream_id
= event
->id
;
5663 if (sample_type
& PERF_SAMPLE_CPU
) {
5664 data
->cpu_entry
.cpu
= raw_smp_processor_id();
5665 data
->cpu_entry
.reserved
= 0;
5669 void perf_event_header__init_id(struct perf_event_header
*header
,
5670 struct perf_sample_data
*data
,
5671 struct perf_event
*event
)
5673 if (event
->attr
.sample_id_all
)
5674 __perf_event_header__init_id(header
, data
, event
);
5677 static void __perf_event__output_id_sample(struct perf_output_handle
*handle
,
5678 struct perf_sample_data
*data
)
5680 u64 sample_type
= data
->type
;
5682 if (sample_type
& PERF_SAMPLE_TID
)
5683 perf_output_put(handle
, data
->tid_entry
);
5685 if (sample_type
& PERF_SAMPLE_TIME
)
5686 perf_output_put(handle
, data
->time
);
5688 if (sample_type
& PERF_SAMPLE_ID
)
5689 perf_output_put(handle
, data
->id
);
5691 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
5692 perf_output_put(handle
, data
->stream_id
);
5694 if (sample_type
& PERF_SAMPLE_CPU
)
5695 perf_output_put(handle
, data
->cpu_entry
);
5697 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
5698 perf_output_put(handle
, data
->id
);
5701 void perf_event__output_id_sample(struct perf_event
*event
,
5702 struct perf_output_handle
*handle
,
5703 struct perf_sample_data
*sample
)
5705 if (event
->attr
.sample_id_all
)
5706 __perf_event__output_id_sample(handle
, sample
);
5709 static void perf_output_read_one(struct perf_output_handle
*handle
,
5710 struct perf_event
*event
,
5711 u64 enabled
, u64 running
)
5713 u64 read_format
= event
->attr
.read_format
;
5717 values
[n
++] = perf_event_count(event
);
5718 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
5719 values
[n
++] = enabled
+
5720 atomic64_read(&event
->child_total_time_enabled
);
5722 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
5723 values
[n
++] = running
+
5724 atomic64_read(&event
->child_total_time_running
);
5726 if (read_format
& PERF_FORMAT_ID
)
5727 values
[n
++] = primary_event_id(event
);
5729 __output_copy(handle
, values
, n
* sizeof(u64
));
5732 static void perf_output_read_group(struct perf_output_handle
*handle
,
5733 struct perf_event
*event
,
5734 u64 enabled
, u64 running
)
5736 struct perf_event
*leader
= event
->group_leader
, *sub
;
5737 u64 read_format
= event
->attr
.read_format
;
5741 values
[n
++] = 1 + leader
->nr_siblings
;
5743 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
5744 values
[n
++] = enabled
;
5746 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
5747 values
[n
++] = running
;
5749 if (leader
!= event
)
5750 leader
->pmu
->read(leader
);
5752 values
[n
++] = perf_event_count(leader
);
5753 if (read_format
& PERF_FORMAT_ID
)
5754 values
[n
++] = primary_event_id(leader
);
5756 __output_copy(handle
, values
, n
* sizeof(u64
));
5758 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
5761 if ((sub
!= event
) &&
5762 (sub
->state
== PERF_EVENT_STATE_ACTIVE
))
5763 sub
->pmu
->read(sub
);
5765 values
[n
++] = perf_event_count(sub
);
5766 if (read_format
& PERF_FORMAT_ID
)
5767 values
[n
++] = primary_event_id(sub
);
5769 __output_copy(handle
, values
, n
* sizeof(u64
));
5773 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5774 PERF_FORMAT_TOTAL_TIME_RUNNING)
5777 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
5779 * The problem is that its both hard and excessively expensive to iterate the
5780 * child list, not to mention that its impossible to IPI the children running
5781 * on another CPU, from interrupt/NMI context.
5783 static void perf_output_read(struct perf_output_handle
*handle
,
5784 struct perf_event
*event
)
5786 u64 enabled
= 0, running
= 0, now
;
5787 u64 read_format
= event
->attr
.read_format
;
5790 * compute total_time_enabled, total_time_running
5791 * based on snapshot values taken when the event
5792 * was last scheduled in.
5794 * we cannot simply called update_context_time()
5795 * because of locking issue as we are called in
5798 if (read_format
& PERF_FORMAT_TOTAL_TIMES
)
5799 calc_timer_values(event
, &now
, &enabled
, &running
);
5801 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
)
5802 perf_output_read_group(handle
, event
, enabled
, running
);
5804 perf_output_read_one(handle
, event
, enabled
, running
);
5807 void perf_output_sample(struct perf_output_handle
*handle
,
5808 struct perf_event_header
*header
,
5809 struct perf_sample_data
*data
,
5810 struct perf_event
*event
)
5812 u64 sample_type
= data
->type
;
5814 perf_output_put(handle
, *header
);
5816 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
5817 perf_output_put(handle
, data
->id
);
5819 if (sample_type
& PERF_SAMPLE_IP
)
5820 perf_output_put(handle
, data
->ip
);
5822 if (sample_type
& PERF_SAMPLE_TID
)
5823 perf_output_put(handle
, data
->tid_entry
);
5825 if (sample_type
& PERF_SAMPLE_TIME
)
5826 perf_output_put(handle
, data
->time
);
5828 if (sample_type
& PERF_SAMPLE_ADDR
)
5829 perf_output_put(handle
, data
->addr
);
5831 if (sample_type
& PERF_SAMPLE_ID
)
5832 perf_output_put(handle
, data
->id
);
5834 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
5835 perf_output_put(handle
, data
->stream_id
);
5837 if (sample_type
& PERF_SAMPLE_CPU
)
5838 perf_output_put(handle
, data
->cpu_entry
);
5840 if (sample_type
& PERF_SAMPLE_PERIOD
)
5841 perf_output_put(handle
, data
->period
);
5843 if (sample_type
& PERF_SAMPLE_READ
)
5844 perf_output_read(handle
, event
);
5846 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
5847 if (data
->callchain
) {
5850 if (data
->callchain
)
5851 size
+= data
->callchain
->nr
;
5853 size
*= sizeof(u64
);
5855 __output_copy(handle
, data
->callchain
, size
);
5858 perf_output_put(handle
, nr
);
5862 if (sample_type
& PERF_SAMPLE_RAW
) {
5863 struct perf_raw_record
*raw
= data
->raw
;
5866 struct perf_raw_frag
*frag
= &raw
->frag
;
5868 perf_output_put(handle
, raw
->size
);
5871 __output_custom(handle
, frag
->copy
,
5872 frag
->data
, frag
->size
);
5874 __output_copy(handle
, frag
->data
,
5877 if (perf_raw_frag_last(frag
))
5882 __output_skip(handle
, NULL
, frag
->pad
);
5888 .size
= sizeof(u32
),
5891 perf_output_put(handle
, raw
);
5895 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
5896 if (data
->br_stack
) {
5899 size
= data
->br_stack
->nr
5900 * sizeof(struct perf_branch_entry
);
5902 perf_output_put(handle
, data
->br_stack
->nr
);
5903 perf_output_copy(handle
, data
->br_stack
->entries
, size
);
5906 * we always store at least the value of nr
5909 perf_output_put(handle
, nr
);
5913 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
5914 u64 abi
= data
->regs_user
.abi
;
5917 * If there are no regs to dump, notice it through
5918 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5920 perf_output_put(handle
, abi
);
5923 u64 mask
= event
->attr
.sample_regs_user
;
5924 perf_output_sample_regs(handle
,
5925 data
->regs_user
.regs
,
5930 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
5931 perf_output_sample_ustack(handle
,
5932 data
->stack_user_size
,
5933 data
->regs_user
.regs
);
5936 if (sample_type
& PERF_SAMPLE_WEIGHT
)
5937 perf_output_put(handle
, data
->weight
);
5939 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
5940 perf_output_put(handle
, data
->data_src
.val
);
5942 if (sample_type
& PERF_SAMPLE_TRANSACTION
)
5943 perf_output_put(handle
, data
->txn
);
5945 if (sample_type
& PERF_SAMPLE_REGS_INTR
) {
5946 u64 abi
= data
->regs_intr
.abi
;
5948 * If there are no regs to dump, notice it through
5949 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5951 perf_output_put(handle
, abi
);
5954 u64 mask
= event
->attr
.sample_regs_intr
;
5956 perf_output_sample_regs(handle
,
5957 data
->regs_intr
.regs
,
5962 if (!event
->attr
.watermark
) {
5963 int wakeup_events
= event
->attr
.wakeup_events
;
5965 if (wakeup_events
) {
5966 struct ring_buffer
*rb
= handle
->rb
;
5967 int events
= local_inc_return(&rb
->events
);
5969 if (events
>= wakeup_events
) {
5970 local_sub(wakeup_events
, &rb
->events
);
5971 local_inc(&rb
->wakeup
);
5977 void perf_prepare_sample(struct perf_event_header
*header
,
5978 struct perf_sample_data
*data
,
5979 struct perf_event
*event
,
5980 struct pt_regs
*regs
)
5982 u64 sample_type
= event
->attr
.sample_type
;
5984 header
->type
= PERF_RECORD_SAMPLE
;
5985 header
->size
= sizeof(*header
) + event
->header_size
;
5988 header
->misc
|= perf_misc_flags(regs
);
5990 __perf_event_header__init_id(header
, data
, event
);
5992 if (sample_type
& PERF_SAMPLE_IP
)
5993 data
->ip
= perf_instruction_pointer(regs
);
5995 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
5998 data
->callchain
= perf_callchain(event
, regs
);
6000 if (data
->callchain
)
6001 size
+= data
->callchain
->nr
;
6003 header
->size
+= size
* sizeof(u64
);
6006 if (sample_type
& PERF_SAMPLE_RAW
) {
6007 struct perf_raw_record
*raw
= data
->raw
;
6011 struct perf_raw_frag
*frag
= &raw
->frag
;
6016 if (perf_raw_frag_last(frag
))
6021 size
= round_up(sum
+ sizeof(u32
), sizeof(u64
));
6022 raw
->size
= size
- sizeof(u32
);
6023 frag
->pad
= raw
->size
- sum
;
6028 header
->size
+= size
;
6031 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
6032 int size
= sizeof(u64
); /* nr */
6033 if (data
->br_stack
) {
6034 size
+= data
->br_stack
->nr
6035 * sizeof(struct perf_branch_entry
);
6037 header
->size
+= size
;
6040 if (sample_type
& (PERF_SAMPLE_REGS_USER
| PERF_SAMPLE_STACK_USER
))
6041 perf_sample_regs_user(&data
->regs_user
, regs
,
6042 &data
->regs_user_copy
);
6044 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
6045 /* regs dump ABI info */
6046 int size
= sizeof(u64
);
6048 if (data
->regs_user
.regs
) {
6049 u64 mask
= event
->attr
.sample_regs_user
;
6050 size
+= hweight64(mask
) * sizeof(u64
);
6053 header
->size
+= size
;
6056 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
6058 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6059 * processed as the last one or have additional check added
6060 * in case new sample type is added, because we could eat
6061 * up the rest of the sample size.
6063 u16 stack_size
= event
->attr
.sample_stack_user
;
6064 u16 size
= sizeof(u64
);
6066 stack_size
= perf_sample_ustack_size(stack_size
, header
->size
,
6067 data
->regs_user
.regs
);
6070 * If there is something to dump, add space for the dump
6071 * itself and for the field that tells the dynamic size,
6072 * which is how many have been actually dumped.
6075 size
+= sizeof(u64
) + stack_size
;
6077 data
->stack_user_size
= stack_size
;
6078 header
->size
+= size
;
6081 if (sample_type
& PERF_SAMPLE_REGS_INTR
) {
6082 /* regs dump ABI info */
6083 int size
= sizeof(u64
);
6085 perf_sample_regs_intr(&data
->regs_intr
, regs
);
6087 if (data
->regs_intr
.regs
) {
6088 u64 mask
= event
->attr
.sample_regs_intr
;
6090 size
+= hweight64(mask
) * sizeof(u64
);
6093 header
->size
+= size
;
6097 static void __always_inline
6098 __perf_event_output(struct perf_event
*event
,
6099 struct perf_sample_data
*data
,
6100 struct pt_regs
*regs
,
6101 int (*output_begin
)(struct perf_output_handle
*,
6102 struct perf_event
*,
6105 struct perf_output_handle handle
;
6106 struct perf_event_header header
;
6108 /* protect the callchain buffers */
6111 perf_prepare_sample(&header
, data
, event
, regs
);
6113 if (output_begin(&handle
, event
, header
.size
))
6116 perf_output_sample(&handle
, &header
, data
, event
);
6118 perf_output_end(&handle
);
6125 perf_event_output_forward(struct perf_event
*event
,
6126 struct perf_sample_data
*data
,
6127 struct pt_regs
*regs
)
6129 __perf_event_output(event
, data
, regs
, perf_output_begin_forward
);
6133 perf_event_output_backward(struct perf_event
*event
,
6134 struct perf_sample_data
*data
,
6135 struct pt_regs
*regs
)
6137 __perf_event_output(event
, data
, regs
, perf_output_begin_backward
);
6141 perf_event_output(struct perf_event
*event
,
6142 struct perf_sample_data
*data
,
6143 struct pt_regs
*regs
)
6145 __perf_event_output(event
, data
, regs
, perf_output_begin
);
6152 struct perf_read_event
{
6153 struct perf_event_header header
;
6160 perf_event_read_event(struct perf_event
*event
,
6161 struct task_struct
*task
)
6163 struct perf_output_handle handle
;
6164 struct perf_sample_data sample
;
6165 struct perf_read_event read_event
= {
6167 .type
= PERF_RECORD_READ
,
6169 .size
= sizeof(read_event
) + event
->read_size
,
6171 .pid
= perf_event_pid(event
, task
),
6172 .tid
= perf_event_tid(event
, task
),
6176 perf_event_header__init_id(&read_event
.header
, &sample
, event
);
6177 ret
= perf_output_begin(&handle
, event
, read_event
.header
.size
);
6181 perf_output_put(&handle
, read_event
);
6182 perf_output_read(&handle
, event
);
6183 perf_event__output_id_sample(event
, &handle
, &sample
);
6185 perf_output_end(&handle
);
6188 typedef void (perf_iterate_f
)(struct perf_event
*event
, void *data
);
6191 perf_iterate_ctx(struct perf_event_context
*ctx
,
6192 perf_iterate_f output
,
6193 void *data
, bool all
)
6195 struct perf_event
*event
;
6197 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
6199 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
6201 if (!event_filter_match(event
))
6205 output(event
, data
);
6209 static void perf_iterate_sb_cpu(perf_iterate_f output
, void *data
)
6211 struct pmu_event_list
*pel
= this_cpu_ptr(&pmu_sb_events
);
6212 struct perf_event
*event
;
6214 list_for_each_entry_rcu(event
, &pel
->list
, sb_list
) {
6216 * Skip events that are not fully formed yet; ensure that
6217 * if we observe event->ctx, both event and ctx will be
6218 * complete enough. See perf_install_in_context().
6220 if (!smp_load_acquire(&event
->ctx
))
6223 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
6225 if (!event_filter_match(event
))
6227 output(event
, data
);
6232 * Iterate all events that need to receive side-band events.
6234 * For new callers; ensure that account_pmu_sb_event() includes
6235 * your event, otherwise it might not get delivered.
6238 perf_iterate_sb(perf_iterate_f output
, void *data
,
6239 struct perf_event_context
*task_ctx
)
6241 struct perf_event_context
*ctx
;
6248 * If we have task_ctx != NULL we only notify the task context itself.
6249 * The task_ctx is set only for EXIT events before releasing task
6253 perf_iterate_ctx(task_ctx
, output
, data
, false);
6257 perf_iterate_sb_cpu(output
, data
);
6259 for_each_task_context_nr(ctxn
) {
6260 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
6262 perf_iterate_ctx(ctx
, output
, data
, false);
6270 * Clear all file-based filters at exec, they'll have to be
6271 * re-instated when/if these objects are mmapped again.
6273 static void perf_event_addr_filters_exec(struct perf_event
*event
, void *data
)
6275 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
6276 struct perf_addr_filter
*filter
;
6277 unsigned int restart
= 0, count
= 0;
6278 unsigned long flags
;
6280 if (!has_addr_filter(event
))
6283 raw_spin_lock_irqsave(&ifh
->lock
, flags
);
6284 list_for_each_entry(filter
, &ifh
->list
, entry
) {
6285 if (filter
->inode
) {
6286 event
->addr_filters_offs
[count
] = 0;
6294 event
->addr_filters_gen
++;
6295 raw_spin_unlock_irqrestore(&ifh
->lock
, flags
);
6298 perf_event_stop(event
, 1);
6301 void perf_event_exec(void)
6303 struct perf_event_context
*ctx
;
6307 for_each_task_context_nr(ctxn
) {
6308 ctx
= current
->perf_event_ctxp
[ctxn
];
6312 perf_event_enable_on_exec(ctxn
);
6314 perf_iterate_ctx(ctx
, perf_event_addr_filters_exec
, NULL
,
6320 struct remote_output
{
6321 struct ring_buffer
*rb
;
6325 static void __perf_event_output_stop(struct perf_event
*event
, void *data
)
6327 struct perf_event
*parent
= event
->parent
;
6328 struct remote_output
*ro
= data
;
6329 struct ring_buffer
*rb
= ro
->rb
;
6330 struct stop_event_data sd
= {
6334 if (!has_aux(event
))
6341 * In case of inheritance, it will be the parent that links to the
6342 * ring-buffer, but it will be the child that's actually using it.
6344 * We are using event::rb to determine if the event should be stopped,
6345 * however this may race with ring_buffer_attach() (through set_output),
6346 * which will make us skip the event that actually needs to be stopped.
6347 * So ring_buffer_attach() has to stop an aux event before re-assigning
6350 if (rcu_dereference(parent
->rb
) == rb
)
6351 ro
->err
= __perf_event_stop(&sd
);
6354 static int __perf_pmu_output_stop(void *info
)
6356 struct perf_event
*event
= info
;
6357 struct pmu
*pmu
= event
->pmu
;
6358 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
6359 struct remote_output ro
= {
6364 perf_iterate_ctx(&cpuctx
->ctx
, __perf_event_output_stop
, &ro
, false);
6365 if (cpuctx
->task_ctx
)
6366 perf_iterate_ctx(cpuctx
->task_ctx
, __perf_event_output_stop
,
6373 static void perf_pmu_output_stop(struct perf_event
*event
)
6375 struct perf_event
*iter
;
6380 list_for_each_entry_rcu(iter
, &event
->rb
->event_list
, rb_entry
) {
6382 * For per-CPU events, we need to make sure that neither they
6383 * nor their children are running; for cpu==-1 events it's
6384 * sufficient to stop the event itself if it's active, since
6385 * it can't have children.
6389 cpu
= READ_ONCE(iter
->oncpu
);
6394 err
= cpu_function_call(cpu
, __perf_pmu_output_stop
, event
);
6395 if (err
== -EAGAIN
) {
6404 * task tracking -- fork/exit
6406 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6409 struct perf_task_event
{
6410 struct task_struct
*task
;
6411 struct perf_event_context
*task_ctx
;
6414 struct perf_event_header header
;
6424 static int perf_event_task_match(struct perf_event
*event
)
6426 return event
->attr
.comm
|| event
->attr
.mmap
||
6427 event
->attr
.mmap2
|| event
->attr
.mmap_data
||
6431 static void perf_event_task_output(struct perf_event
*event
,
6434 struct perf_task_event
*task_event
= data
;
6435 struct perf_output_handle handle
;
6436 struct perf_sample_data sample
;
6437 struct task_struct
*task
= task_event
->task
;
6438 int ret
, size
= task_event
->event_id
.header
.size
;
6440 if (!perf_event_task_match(event
))
6443 perf_event_header__init_id(&task_event
->event_id
.header
, &sample
, event
);
6445 ret
= perf_output_begin(&handle
, event
,
6446 task_event
->event_id
.header
.size
);
6450 task_event
->event_id
.pid
= perf_event_pid(event
, task
);
6451 task_event
->event_id
.ppid
= perf_event_pid(event
, current
);
6453 task_event
->event_id
.tid
= perf_event_tid(event
, task
);
6454 task_event
->event_id
.ptid
= perf_event_tid(event
, current
);
6456 task_event
->event_id
.time
= perf_event_clock(event
);
6458 perf_output_put(&handle
, task_event
->event_id
);
6460 perf_event__output_id_sample(event
, &handle
, &sample
);
6462 perf_output_end(&handle
);
6464 task_event
->event_id
.header
.size
= size
;
6467 static void perf_event_task(struct task_struct
*task
,
6468 struct perf_event_context
*task_ctx
,
6471 struct perf_task_event task_event
;
6473 if (!atomic_read(&nr_comm_events
) &&
6474 !atomic_read(&nr_mmap_events
) &&
6475 !atomic_read(&nr_task_events
))
6478 task_event
= (struct perf_task_event
){
6480 .task_ctx
= task_ctx
,
6483 .type
= new ? PERF_RECORD_FORK
: PERF_RECORD_EXIT
,
6485 .size
= sizeof(task_event
.event_id
),
6495 perf_iterate_sb(perf_event_task_output
,
6500 void perf_event_fork(struct task_struct
*task
)
6502 perf_event_task(task
, NULL
, 1);
6503 perf_event_namespaces(task
);
6510 struct perf_comm_event
{
6511 struct task_struct
*task
;
6516 struct perf_event_header header
;
6523 static int perf_event_comm_match(struct perf_event
*event
)
6525 return event
->attr
.comm
;
6528 static void perf_event_comm_output(struct perf_event
*event
,
6531 struct perf_comm_event
*comm_event
= data
;
6532 struct perf_output_handle handle
;
6533 struct perf_sample_data sample
;
6534 int size
= comm_event
->event_id
.header
.size
;
6537 if (!perf_event_comm_match(event
))
6540 perf_event_header__init_id(&comm_event
->event_id
.header
, &sample
, event
);
6541 ret
= perf_output_begin(&handle
, event
,
6542 comm_event
->event_id
.header
.size
);
6547 comm_event
->event_id
.pid
= perf_event_pid(event
, comm_event
->task
);
6548 comm_event
->event_id
.tid
= perf_event_tid(event
, comm_event
->task
);
6550 perf_output_put(&handle
, comm_event
->event_id
);
6551 __output_copy(&handle
, comm_event
->comm
,
6552 comm_event
->comm_size
);
6554 perf_event__output_id_sample(event
, &handle
, &sample
);
6556 perf_output_end(&handle
);
6558 comm_event
->event_id
.header
.size
= size
;
6561 static void perf_event_comm_event(struct perf_comm_event
*comm_event
)
6563 char comm
[TASK_COMM_LEN
];
6566 memset(comm
, 0, sizeof(comm
));
6567 strlcpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
6568 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
6570 comm_event
->comm
= comm
;
6571 comm_event
->comm_size
= size
;
6573 comm_event
->event_id
.header
.size
= sizeof(comm_event
->event_id
) + size
;
6575 perf_iterate_sb(perf_event_comm_output
,
6580 void perf_event_comm(struct task_struct
*task
, bool exec
)
6582 struct perf_comm_event comm_event
;
6584 if (!atomic_read(&nr_comm_events
))
6587 comm_event
= (struct perf_comm_event
){
6593 .type
= PERF_RECORD_COMM
,
6594 .misc
= exec
? PERF_RECORD_MISC_COMM_EXEC
: 0,
6602 perf_event_comm_event(&comm_event
);
6606 * namespaces tracking
6609 struct perf_namespaces_event
{
6610 struct task_struct
*task
;
6613 struct perf_event_header header
;
6618 struct perf_ns_link_info link_info
[NR_NAMESPACES
];
6622 static int perf_event_namespaces_match(struct perf_event
*event
)
6624 return event
->attr
.namespaces
;
6627 static void perf_event_namespaces_output(struct perf_event
*event
,
6630 struct perf_namespaces_event
*namespaces_event
= data
;
6631 struct perf_output_handle handle
;
6632 struct perf_sample_data sample
;
6635 if (!perf_event_namespaces_match(event
))
6638 perf_event_header__init_id(&namespaces_event
->event_id
.header
,
6640 ret
= perf_output_begin(&handle
, event
,
6641 namespaces_event
->event_id
.header
.size
);
6645 namespaces_event
->event_id
.pid
= perf_event_pid(event
,
6646 namespaces_event
->task
);
6647 namespaces_event
->event_id
.tid
= perf_event_tid(event
,
6648 namespaces_event
->task
);
6650 perf_output_put(&handle
, namespaces_event
->event_id
);
6652 perf_event__output_id_sample(event
, &handle
, &sample
);
6654 perf_output_end(&handle
);
6657 static void perf_fill_ns_link_info(struct perf_ns_link_info
*ns_link_info
,
6658 struct task_struct
*task
,
6659 const struct proc_ns_operations
*ns_ops
)
6661 struct path ns_path
;
6662 struct inode
*ns_inode
;
6665 error
= ns_get_path(&ns_path
, task
, ns_ops
);
6667 ns_inode
= ns_path
.dentry
->d_inode
;
6668 ns_link_info
->dev
= new_encode_dev(ns_inode
->i_sb
->s_dev
);
6669 ns_link_info
->ino
= ns_inode
->i_ino
;
6673 void perf_event_namespaces(struct task_struct
*task
)
6675 struct perf_namespaces_event namespaces_event
;
6676 struct perf_ns_link_info
*ns_link_info
;
6678 if (!atomic_read(&nr_namespaces_events
))
6681 namespaces_event
= (struct perf_namespaces_event
){
6685 .type
= PERF_RECORD_NAMESPACES
,
6687 .size
= sizeof(namespaces_event
.event_id
),
6691 .nr_namespaces
= NR_NAMESPACES
,
6692 /* .link_info[NR_NAMESPACES] */
6696 ns_link_info
= namespaces_event
.event_id
.link_info
;
6698 perf_fill_ns_link_info(&ns_link_info
[MNT_NS_INDEX
],
6699 task
, &mntns_operations
);
6701 #ifdef CONFIG_USER_NS
6702 perf_fill_ns_link_info(&ns_link_info
[USER_NS_INDEX
],
6703 task
, &userns_operations
);
6705 #ifdef CONFIG_NET_NS
6706 perf_fill_ns_link_info(&ns_link_info
[NET_NS_INDEX
],
6707 task
, &netns_operations
);
6709 #ifdef CONFIG_UTS_NS
6710 perf_fill_ns_link_info(&ns_link_info
[UTS_NS_INDEX
],
6711 task
, &utsns_operations
);
6713 #ifdef CONFIG_IPC_NS
6714 perf_fill_ns_link_info(&ns_link_info
[IPC_NS_INDEX
],
6715 task
, &ipcns_operations
);
6717 #ifdef CONFIG_PID_NS
6718 perf_fill_ns_link_info(&ns_link_info
[PID_NS_INDEX
],
6719 task
, &pidns_operations
);
6721 #ifdef CONFIG_CGROUPS
6722 perf_fill_ns_link_info(&ns_link_info
[CGROUP_NS_INDEX
],
6723 task
, &cgroupns_operations
);
6726 perf_iterate_sb(perf_event_namespaces_output
,
6735 struct perf_mmap_event
{
6736 struct vm_area_struct
*vma
;
6738 const char *file_name
;
6746 struct perf_event_header header
;
6756 static int perf_event_mmap_match(struct perf_event
*event
,
6759 struct perf_mmap_event
*mmap_event
= data
;
6760 struct vm_area_struct
*vma
= mmap_event
->vma
;
6761 int executable
= vma
->vm_flags
& VM_EXEC
;
6763 return (!executable
&& event
->attr
.mmap_data
) ||
6764 (executable
&& (event
->attr
.mmap
|| event
->attr
.mmap2
));
6767 static void perf_event_mmap_output(struct perf_event
*event
,
6770 struct perf_mmap_event
*mmap_event
= data
;
6771 struct perf_output_handle handle
;
6772 struct perf_sample_data sample
;
6773 int size
= mmap_event
->event_id
.header
.size
;
6776 if (!perf_event_mmap_match(event
, data
))
6779 if (event
->attr
.mmap2
) {
6780 mmap_event
->event_id
.header
.type
= PERF_RECORD_MMAP2
;
6781 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->maj
);
6782 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->min
);
6783 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->ino
);
6784 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->ino_generation
);
6785 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->prot
);
6786 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->flags
);
6789 perf_event_header__init_id(&mmap_event
->event_id
.header
, &sample
, event
);
6790 ret
= perf_output_begin(&handle
, event
,
6791 mmap_event
->event_id
.header
.size
);
6795 mmap_event
->event_id
.pid
= perf_event_pid(event
, current
);
6796 mmap_event
->event_id
.tid
= perf_event_tid(event
, current
);
6798 perf_output_put(&handle
, mmap_event
->event_id
);
6800 if (event
->attr
.mmap2
) {
6801 perf_output_put(&handle
, mmap_event
->maj
);
6802 perf_output_put(&handle
, mmap_event
->min
);
6803 perf_output_put(&handle
, mmap_event
->ino
);
6804 perf_output_put(&handle
, mmap_event
->ino_generation
);
6805 perf_output_put(&handle
, mmap_event
->prot
);
6806 perf_output_put(&handle
, mmap_event
->flags
);
6809 __output_copy(&handle
, mmap_event
->file_name
,
6810 mmap_event
->file_size
);
6812 perf_event__output_id_sample(event
, &handle
, &sample
);
6814 perf_output_end(&handle
);
6816 mmap_event
->event_id
.header
.size
= size
;
6819 static void perf_event_mmap_event(struct perf_mmap_event
*mmap_event
)
6821 struct vm_area_struct
*vma
= mmap_event
->vma
;
6822 struct file
*file
= vma
->vm_file
;
6823 int maj
= 0, min
= 0;
6824 u64 ino
= 0, gen
= 0;
6825 u32 prot
= 0, flags
= 0;
6831 if (vma
->vm_flags
& VM_READ
)
6833 if (vma
->vm_flags
& VM_WRITE
)
6835 if (vma
->vm_flags
& VM_EXEC
)
6838 if (vma
->vm_flags
& VM_MAYSHARE
)
6841 flags
= MAP_PRIVATE
;
6843 if (vma
->vm_flags
& VM_DENYWRITE
)
6844 flags
|= MAP_DENYWRITE
;
6845 if (vma
->vm_flags
& VM_MAYEXEC
)
6846 flags
|= MAP_EXECUTABLE
;
6847 if (vma
->vm_flags
& VM_LOCKED
)
6848 flags
|= MAP_LOCKED
;
6849 if (vma
->vm_flags
& VM_HUGETLB
)
6850 flags
|= MAP_HUGETLB
;
6853 struct inode
*inode
;
6856 buf
= kmalloc(PATH_MAX
, GFP_KERNEL
);
6862 * d_path() works from the end of the rb backwards, so we
6863 * need to add enough zero bytes after the string to handle
6864 * the 64bit alignment we do later.
6866 name
= file_path(file
, buf
, PATH_MAX
- sizeof(u64
));
6871 inode
= file_inode(vma
->vm_file
);
6872 dev
= inode
->i_sb
->s_dev
;
6874 gen
= inode
->i_generation
;
6880 if (vma
->vm_ops
&& vma
->vm_ops
->name
) {
6881 name
= (char *) vma
->vm_ops
->name(vma
);
6886 name
= (char *)arch_vma_name(vma
);
6890 if (vma
->vm_start
<= vma
->vm_mm
->start_brk
&&
6891 vma
->vm_end
>= vma
->vm_mm
->brk
) {
6895 if (vma
->vm_start
<= vma
->vm_mm
->start_stack
&&
6896 vma
->vm_end
>= vma
->vm_mm
->start_stack
) {
6906 strlcpy(tmp
, name
, sizeof(tmp
));
6910 * Since our buffer works in 8 byte units we need to align our string
6911 * size to a multiple of 8. However, we must guarantee the tail end is
6912 * zero'd out to avoid leaking random bits to userspace.
6914 size
= strlen(name
)+1;
6915 while (!IS_ALIGNED(size
, sizeof(u64
)))
6916 name
[size
++] = '\0';
6918 mmap_event
->file_name
= name
;
6919 mmap_event
->file_size
= size
;
6920 mmap_event
->maj
= maj
;
6921 mmap_event
->min
= min
;
6922 mmap_event
->ino
= ino
;
6923 mmap_event
->ino_generation
= gen
;
6924 mmap_event
->prot
= prot
;
6925 mmap_event
->flags
= flags
;
6927 if (!(vma
->vm_flags
& VM_EXEC
))
6928 mmap_event
->event_id
.header
.misc
|= PERF_RECORD_MISC_MMAP_DATA
;
6930 mmap_event
->event_id
.header
.size
= sizeof(mmap_event
->event_id
) + size
;
6932 perf_iterate_sb(perf_event_mmap_output
,
6940 * Check whether inode and address range match filter criteria.
6942 static bool perf_addr_filter_match(struct perf_addr_filter
*filter
,
6943 struct file
*file
, unsigned long offset
,
6946 if (filter
->inode
!= file_inode(file
))
6949 if (filter
->offset
> offset
+ size
)
6952 if (filter
->offset
+ filter
->size
< offset
)
6958 static void __perf_addr_filters_adjust(struct perf_event
*event
, void *data
)
6960 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
6961 struct vm_area_struct
*vma
= data
;
6962 unsigned long off
= vma
->vm_pgoff
<< PAGE_SHIFT
, flags
;
6963 struct file
*file
= vma
->vm_file
;
6964 struct perf_addr_filter
*filter
;
6965 unsigned int restart
= 0, count
= 0;
6967 if (!has_addr_filter(event
))
6973 raw_spin_lock_irqsave(&ifh
->lock
, flags
);
6974 list_for_each_entry(filter
, &ifh
->list
, entry
) {
6975 if (perf_addr_filter_match(filter
, file
, off
,
6976 vma
->vm_end
- vma
->vm_start
)) {
6977 event
->addr_filters_offs
[count
] = vma
->vm_start
;
6985 event
->addr_filters_gen
++;
6986 raw_spin_unlock_irqrestore(&ifh
->lock
, flags
);
6989 perf_event_stop(event
, 1);
6993 * Adjust all task's events' filters to the new vma
6995 static void perf_addr_filters_adjust(struct vm_area_struct
*vma
)
6997 struct perf_event_context
*ctx
;
7001 * Data tracing isn't supported yet and as such there is no need
7002 * to keep track of anything that isn't related to executable code:
7004 if (!(vma
->vm_flags
& VM_EXEC
))
7008 for_each_task_context_nr(ctxn
) {
7009 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
7013 perf_iterate_ctx(ctx
, __perf_addr_filters_adjust
, vma
, true);
7018 void perf_event_mmap(struct vm_area_struct
*vma
)
7020 struct perf_mmap_event mmap_event
;
7022 if (!atomic_read(&nr_mmap_events
))
7025 mmap_event
= (struct perf_mmap_event
){
7031 .type
= PERF_RECORD_MMAP
,
7032 .misc
= PERF_RECORD_MISC_USER
,
7037 .start
= vma
->vm_start
,
7038 .len
= vma
->vm_end
- vma
->vm_start
,
7039 .pgoff
= (u64
)vma
->vm_pgoff
<< PAGE_SHIFT
,
7041 /* .maj (attr_mmap2 only) */
7042 /* .min (attr_mmap2 only) */
7043 /* .ino (attr_mmap2 only) */
7044 /* .ino_generation (attr_mmap2 only) */
7045 /* .prot (attr_mmap2 only) */
7046 /* .flags (attr_mmap2 only) */
7049 perf_addr_filters_adjust(vma
);
7050 perf_event_mmap_event(&mmap_event
);
7053 void perf_event_aux_event(struct perf_event
*event
, unsigned long head
,
7054 unsigned long size
, u64 flags
)
7056 struct perf_output_handle handle
;
7057 struct perf_sample_data sample
;
7058 struct perf_aux_event
{
7059 struct perf_event_header header
;
7065 .type
= PERF_RECORD_AUX
,
7067 .size
= sizeof(rec
),
7075 perf_event_header__init_id(&rec
.header
, &sample
, event
);
7076 ret
= perf_output_begin(&handle
, event
, rec
.header
.size
);
7081 perf_output_put(&handle
, rec
);
7082 perf_event__output_id_sample(event
, &handle
, &sample
);
7084 perf_output_end(&handle
);
7088 * Lost/dropped samples logging
7090 void perf_log_lost_samples(struct perf_event
*event
, u64 lost
)
7092 struct perf_output_handle handle
;
7093 struct perf_sample_data sample
;
7097 struct perf_event_header header
;
7099 } lost_samples_event
= {
7101 .type
= PERF_RECORD_LOST_SAMPLES
,
7103 .size
= sizeof(lost_samples_event
),
7108 perf_event_header__init_id(&lost_samples_event
.header
, &sample
, event
);
7110 ret
= perf_output_begin(&handle
, event
,
7111 lost_samples_event
.header
.size
);
7115 perf_output_put(&handle
, lost_samples_event
);
7116 perf_event__output_id_sample(event
, &handle
, &sample
);
7117 perf_output_end(&handle
);
7121 * context_switch tracking
7124 struct perf_switch_event
{
7125 struct task_struct
*task
;
7126 struct task_struct
*next_prev
;
7129 struct perf_event_header header
;
7135 static int perf_event_switch_match(struct perf_event
*event
)
7137 return event
->attr
.context_switch
;
7140 static void perf_event_switch_output(struct perf_event
*event
, void *data
)
7142 struct perf_switch_event
*se
= data
;
7143 struct perf_output_handle handle
;
7144 struct perf_sample_data sample
;
7147 if (!perf_event_switch_match(event
))
7150 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7151 if (event
->ctx
->task
) {
7152 se
->event_id
.header
.type
= PERF_RECORD_SWITCH
;
7153 se
->event_id
.header
.size
= sizeof(se
->event_id
.header
);
7155 se
->event_id
.header
.type
= PERF_RECORD_SWITCH_CPU_WIDE
;
7156 se
->event_id
.header
.size
= sizeof(se
->event_id
);
7157 se
->event_id
.next_prev_pid
=
7158 perf_event_pid(event
, se
->next_prev
);
7159 se
->event_id
.next_prev_tid
=
7160 perf_event_tid(event
, se
->next_prev
);
7163 perf_event_header__init_id(&se
->event_id
.header
, &sample
, event
);
7165 ret
= perf_output_begin(&handle
, event
, se
->event_id
.header
.size
);
7169 if (event
->ctx
->task
)
7170 perf_output_put(&handle
, se
->event_id
.header
);
7172 perf_output_put(&handle
, se
->event_id
);
7174 perf_event__output_id_sample(event
, &handle
, &sample
);
7176 perf_output_end(&handle
);
7179 static void perf_event_switch(struct task_struct
*task
,
7180 struct task_struct
*next_prev
, bool sched_in
)
7182 struct perf_switch_event switch_event
;
7184 /* N.B. caller checks nr_switch_events != 0 */
7186 switch_event
= (struct perf_switch_event
){
7188 .next_prev
= next_prev
,
7192 .misc
= sched_in
? 0 : PERF_RECORD_MISC_SWITCH_OUT
,
7195 /* .next_prev_pid */
7196 /* .next_prev_tid */
7200 perf_iterate_sb(perf_event_switch_output
,
7206 * IRQ throttle logging
7209 static void perf_log_throttle(struct perf_event
*event
, int enable
)
7211 struct perf_output_handle handle
;
7212 struct perf_sample_data sample
;
7216 struct perf_event_header header
;
7220 } throttle_event
= {
7222 .type
= PERF_RECORD_THROTTLE
,
7224 .size
= sizeof(throttle_event
),
7226 .time
= perf_event_clock(event
),
7227 .id
= primary_event_id(event
),
7228 .stream_id
= event
->id
,
7232 throttle_event
.header
.type
= PERF_RECORD_UNTHROTTLE
;
7234 perf_event_header__init_id(&throttle_event
.header
, &sample
, event
);
7236 ret
= perf_output_begin(&handle
, event
,
7237 throttle_event
.header
.size
);
7241 perf_output_put(&handle
, throttle_event
);
7242 perf_event__output_id_sample(event
, &handle
, &sample
);
7243 perf_output_end(&handle
);
7246 static void perf_log_itrace_start(struct perf_event
*event
)
7248 struct perf_output_handle handle
;
7249 struct perf_sample_data sample
;
7250 struct perf_aux_event
{
7251 struct perf_event_header header
;
7258 event
= event
->parent
;
7260 if (!(event
->pmu
->capabilities
& PERF_PMU_CAP_ITRACE
) ||
7261 event
->hw
.itrace_started
)
7264 rec
.header
.type
= PERF_RECORD_ITRACE_START
;
7265 rec
.header
.misc
= 0;
7266 rec
.header
.size
= sizeof(rec
);
7267 rec
.pid
= perf_event_pid(event
, current
);
7268 rec
.tid
= perf_event_tid(event
, current
);
7270 perf_event_header__init_id(&rec
.header
, &sample
, event
);
7271 ret
= perf_output_begin(&handle
, event
, rec
.header
.size
);
7276 perf_output_put(&handle
, rec
);
7277 perf_event__output_id_sample(event
, &handle
, &sample
);
7279 perf_output_end(&handle
);
7283 __perf_event_account_interrupt(struct perf_event
*event
, int throttle
)
7285 struct hw_perf_event
*hwc
= &event
->hw
;
7289 seq
= __this_cpu_read(perf_throttled_seq
);
7290 if (seq
!= hwc
->interrupts_seq
) {
7291 hwc
->interrupts_seq
= seq
;
7292 hwc
->interrupts
= 1;
7295 if (unlikely(throttle
7296 && hwc
->interrupts
>= max_samples_per_tick
)) {
7297 __this_cpu_inc(perf_throttled_count
);
7298 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS
);
7299 hwc
->interrupts
= MAX_INTERRUPTS
;
7300 perf_log_throttle(event
, 0);
7305 if (event
->attr
.freq
) {
7306 u64 now
= perf_clock();
7307 s64 delta
= now
- hwc
->freq_time_stamp
;
7309 hwc
->freq_time_stamp
= now
;
7311 if (delta
> 0 && delta
< 2*TICK_NSEC
)
7312 perf_adjust_period(event
, delta
, hwc
->last_period
, true);
7318 int perf_event_account_interrupt(struct perf_event
*event
)
7320 return __perf_event_account_interrupt(event
, 1);
7324 * Generic event overflow handling, sampling.
7327 static int __perf_event_overflow(struct perf_event
*event
,
7328 int throttle
, struct perf_sample_data
*data
,
7329 struct pt_regs
*regs
)
7331 int events
= atomic_read(&event
->event_limit
);
7335 * Non-sampling counters might still use the PMI to fold short
7336 * hardware counters, ignore those.
7338 if (unlikely(!is_sampling_event(event
)))
7341 ret
= __perf_event_account_interrupt(event
, throttle
);
7344 * XXX event_limit might not quite work as expected on inherited
7348 event
->pending_kill
= POLL_IN
;
7349 if (events
&& atomic_dec_and_test(&event
->event_limit
)) {
7351 event
->pending_kill
= POLL_HUP
;
7353 perf_event_disable_inatomic(event
);
7356 READ_ONCE(event
->overflow_handler
)(event
, data
, regs
);
7358 if (*perf_event_fasync(event
) && event
->pending_kill
) {
7359 event
->pending_wakeup
= 1;
7360 irq_work_queue(&event
->pending
);
7366 int perf_event_overflow(struct perf_event
*event
,
7367 struct perf_sample_data
*data
,
7368 struct pt_regs
*regs
)
7370 return __perf_event_overflow(event
, 1, data
, regs
);
7374 * Generic software event infrastructure
7377 struct swevent_htable
{
7378 struct swevent_hlist
*swevent_hlist
;
7379 struct mutex hlist_mutex
;
7382 /* Recursion avoidance in each contexts */
7383 int recursion
[PERF_NR_CONTEXTS
];
7386 static DEFINE_PER_CPU(struct swevent_htable
, swevent_htable
);
7389 * We directly increment event->count and keep a second value in
7390 * event->hw.period_left to count intervals. This period event
7391 * is kept in the range [-sample_period, 0] so that we can use the
7395 u64
perf_swevent_set_period(struct perf_event
*event
)
7397 struct hw_perf_event
*hwc
= &event
->hw
;
7398 u64 period
= hwc
->last_period
;
7402 hwc
->last_period
= hwc
->sample_period
;
7405 old
= val
= local64_read(&hwc
->period_left
);
7409 nr
= div64_u64(period
+ val
, period
);
7410 offset
= nr
* period
;
7412 if (local64_cmpxchg(&hwc
->period_left
, old
, val
) != old
)
7418 static void perf_swevent_overflow(struct perf_event
*event
, u64 overflow
,
7419 struct perf_sample_data
*data
,
7420 struct pt_regs
*regs
)
7422 struct hw_perf_event
*hwc
= &event
->hw
;
7426 overflow
= perf_swevent_set_period(event
);
7428 if (hwc
->interrupts
== MAX_INTERRUPTS
)
7431 for (; overflow
; overflow
--) {
7432 if (__perf_event_overflow(event
, throttle
,
7435 * We inhibit the overflow from happening when
7436 * hwc->interrupts == MAX_INTERRUPTS.
7444 static void perf_swevent_event(struct perf_event
*event
, u64 nr
,
7445 struct perf_sample_data
*data
,
7446 struct pt_regs
*regs
)
7448 struct hw_perf_event
*hwc
= &event
->hw
;
7450 local64_add(nr
, &event
->count
);
7455 if (!is_sampling_event(event
))
7458 if ((event
->attr
.sample_type
& PERF_SAMPLE_PERIOD
) && !event
->attr
.freq
) {
7460 return perf_swevent_overflow(event
, 1, data
, regs
);
7462 data
->period
= event
->hw
.last_period
;
7464 if (nr
== 1 && hwc
->sample_period
== 1 && !event
->attr
.freq
)
7465 return perf_swevent_overflow(event
, 1, data
, regs
);
7467 if (local64_add_negative(nr
, &hwc
->period_left
))
7470 perf_swevent_overflow(event
, 0, data
, regs
);
7473 static int perf_exclude_event(struct perf_event
*event
,
7474 struct pt_regs
*regs
)
7476 if (event
->hw
.state
& PERF_HES_STOPPED
)
7480 if (event
->attr
.exclude_user
&& user_mode(regs
))
7483 if (event
->attr
.exclude_kernel
&& !user_mode(regs
))
7490 static int perf_swevent_match(struct perf_event
*event
,
7491 enum perf_type_id type
,
7493 struct perf_sample_data
*data
,
7494 struct pt_regs
*regs
)
7496 if (event
->attr
.type
!= type
)
7499 if (event
->attr
.config
!= event_id
)
7502 if (perf_exclude_event(event
, regs
))
7508 static inline u64
swevent_hash(u64 type
, u32 event_id
)
7510 u64 val
= event_id
| (type
<< 32);
7512 return hash_64(val
, SWEVENT_HLIST_BITS
);
7515 static inline struct hlist_head
*
7516 __find_swevent_head(struct swevent_hlist
*hlist
, u64 type
, u32 event_id
)
7518 u64 hash
= swevent_hash(type
, event_id
);
7520 return &hlist
->heads
[hash
];
7523 /* For the read side: events when they trigger */
7524 static inline struct hlist_head
*
7525 find_swevent_head_rcu(struct swevent_htable
*swhash
, u64 type
, u32 event_id
)
7527 struct swevent_hlist
*hlist
;
7529 hlist
= rcu_dereference(swhash
->swevent_hlist
);
7533 return __find_swevent_head(hlist
, type
, event_id
);
7536 /* For the event head insertion and removal in the hlist */
7537 static inline struct hlist_head
*
7538 find_swevent_head(struct swevent_htable
*swhash
, struct perf_event
*event
)
7540 struct swevent_hlist
*hlist
;
7541 u32 event_id
= event
->attr
.config
;
7542 u64 type
= event
->attr
.type
;
7545 * Event scheduling is always serialized against hlist allocation
7546 * and release. Which makes the protected version suitable here.
7547 * The context lock guarantees that.
7549 hlist
= rcu_dereference_protected(swhash
->swevent_hlist
,
7550 lockdep_is_held(&event
->ctx
->lock
));
7554 return __find_swevent_head(hlist
, type
, event_id
);
7557 static void do_perf_sw_event(enum perf_type_id type
, u32 event_id
,
7559 struct perf_sample_data
*data
,
7560 struct pt_regs
*regs
)
7562 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7563 struct perf_event
*event
;
7564 struct hlist_head
*head
;
7567 head
= find_swevent_head_rcu(swhash
, type
, event_id
);
7571 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
7572 if (perf_swevent_match(event
, type
, event_id
, data
, regs
))
7573 perf_swevent_event(event
, nr
, data
, regs
);
7579 DEFINE_PER_CPU(struct pt_regs
, __perf_regs
[4]);
7581 int perf_swevent_get_recursion_context(void)
7583 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7585 return get_recursion_context(swhash
->recursion
);
7587 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context
);
7589 void perf_swevent_put_recursion_context(int rctx
)
7591 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7593 put_recursion_context(swhash
->recursion
, rctx
);
7596 void ___perf_sw_event(u32 event_id
, u64 nr
, struct pt_regs
*regs
, u64 addr
)
7598 struct perf_sample_data data
;
7600 if (WARN_ON_ONCE(!regs
))
7603 perf_sample_data_init(&data
, addr
, 0);
7604 do_perf_sw_event(PERF_TYPE_SOFTWARE
, event_id
, nr
, &data
, regs
);
7607 void __perf_sw_event(u32 event_id
, u64 nr
, struct pt_regs
*regs
, u64 addr
)
7611 preempt_disable_notrace();
7612 rctx
= perf_swevent_get_recursion_context();
7613 if (unlikely(rctx
< 0))
7616 ___perf_sw_event(event_id
, nr
, regs
, addr
);
7618 perf_swevent_put_recursion_context(rctx
);
7620 preempt_enable_notrace();
7623 static void perf_swevent_read(struct perf_event
*event
)
7627 static int perf_swevent_add(struct perf_event
*event
, int flags
)
7629 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7630 struct hw_perf_event
*hwc
= &event
->hw
;
7631 struct hlist_head
*head
;
7633 if (is_sampling_event(event
)) {
7634 hwc
->last_period
= hwc
->sample_period
;
7635 perf_swevent_set_period(event
);
7638 hwc
->state
= !(flags
& PERF_EF_START
);
7640 head
= find_swevent_head(swhash
, event
);
7641 if (WARN_ON_ONCE(!head
))
7644 hlist_add_head_rcu(&event
->hlist_entry
, head
);
7645 perf_event_update_userpage(event
);
7650 static void perf_swevent_del(struct perf_event
*event
, int flags
)
7652 hlist_del_rcu(&event
->hlist_entry
);
7655 static void perf_swevent_start(struct perf_event
*event
, int flags
)
7657 event
->hw
.state
= 0;
7660 static void perf_swevent_stop(struct perf_event
*event
, int flags
)
7662 event
->hw
.state
= PERF_HES_STOPPED
;
7665 /* Deref the hlist from the update side */
7666 static inline struct swevent_hlist
*
7667 swevent_hlist_deref(struct swevent_htable
*swhash
)
7669 return rcu_dereference_protected(swhash
->swevent_hlist
,
7670 lockdep_is_held(&swhash
->hlist_mutex
));
7673 static void swevent_hlist_release(struct swevent_htable
*swhash
)
7675 struct swevent_hlist
*hlist
= swevent_hlist_deref(swhash
);
7680 RCU_INIT_POINTER(swhash
->swevent_hlist
, NULL
);
7681 kfree_rcu(hlist
, rcu_head
);
7684 static void swevent_hlist_put_cpu(int cpu
)
7686 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
7688 mutex_lock(&swhash
->hlist_mutex
);
7690 if (!--swhash
->hlist_refcount
)
7691 swevent_hlist_release(swhash
);
7693 mutex_unlock(&swhash
->hlist_mutex
);
7696 static void swevent_hlist_put(void)
7700 for_each_possible_cpu(cpu
)
7701 swevent_hlist_put_cpu(cpu
);
7704 static int swevent_hlist_get_cpu(int cpu
)
7706 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
7709 mutex_lock(&swhash
->hlist_mutex
);
7710 if (!swevent_hlist_deref(swhash
) &&
7711 cpumask_test_cpu(cpu
, perf_online_mask
)) {
7712 struct swevent_hlist
*hlist
;
7714 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
7719 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
7721 swhash
->hlist_refcount
++;
7723 mutex_unlock(&swhash
->hlist_mutex
);
7728 static int swevent_hlist_get(void)
7730 int err
, cpu
, failed_cpu
;
7732 mutex_lock(&pmus_lock
);
7733 for_each_possible_cpu(cpu
) {
7734 err
= swevent_hlist_get_cpu(cpu
);
7740 mutex_unlock(&pmus_lock
);
7743 for_each_possible_cpu(cpu
) {
7744 if (cpu
== failed_cpu
)
7746 swevent_hlist_put_cpu(cpu
);
7748 mutex_unlock(&pmus_lock
);
7752 struct static_key perf_swevent_enabled
[PERF_COUNT_SW_MAX
];
7754 static void sw_perf_event_destroy(struct perf_event
*event
)
7756 u64 event_id
= event
->attr
.config
;
7758 WARN_ON(event
->parent
);
7760 static_key_slow_dec(&perf_swevent_enabled
[event_id
]);
7761 swevent_hlist_put();
7764 static int perf_swevent_init(struct perf_event
*event
)
7766 u64 event_id
= event
->attr
.config
;
7768 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
7772 * no branch sampling for software events
7774 if (has_branch_stack(event
))
7778 case PERF_COUNT_SW_CPU_CLOCK
:
7779 case PERF_COUNT_SW_TASK_CLOCK
:
7786 if (event_id
>= PERF_COUNT_SW_MAX
)
7789 if (!event
->parent
) {
7792 err
= swevent_hlist_get();
7796 static_key_slow_inc(&perf_swevent_enabled
[event_id
]);
7797 event
->destroy
= sw_perf_event_destroy
;
7803 static struct pmu perf_swevent
= {
7804 .task_ctx_nr
= perf_sw_context
,
7806 .capabilities
= PERF_PMU_CAP_NO_NMI
,
7808 .event_init
= perf_swevent_init
,
7809 .add
= perf_swevent_add
,
7810 .del
= perf_swevent_del
,
7811 .start
= perf_swevent_start
,
7812 .stop
= perf_swevent_stop
,
7813 .read
= perf_swevent_read
,
7816 #ifdef CONFIG_EVENT_TRACING
7818 static int perf_tp_filter_match(struct perf_event
*event
,
7819 struct perf_sample_data
*data
)
7821 void *record
= data
->raw
->frag
.data
;
7823 /* only top level events have filters set */
7825 event
= event
->parent
;
7827 if (likely(!event
->filter
) || filter_match_preds(event
->filter
, record
))
7832 static int perf_tp_event_match(struct perf_event
*event
,
7833 struct perf_sample_data
*data
,
7834 struct pt_regs
*regs
)
7836 if (event
->hw
.state
& PERF_HES_STOPPED
)
7839 * All tracepoints are from kernel-space.
7841 if (event
->attr
.exclude_kernel
)
7844 if (!perf_tp_filter_match(event
, data
))
7850 void perf_trace_run_bpf_submit(void *raw_data
, int size
, int rctx
,
7851 struct trace_event_call
*call
, u64 count
,
7852 struct pt_regs
*regs
, struct hlist_head
*head
,
7853 struct task_struct
*task
)
7855 struct bpf_prog
*prog
= call
->prog
;
7858 *(struct pt_regs
**)raw_data
= regs
;
7859 if (!trace_call_bpf(prog
, raw_data
) || hlist_empty(head
)) {
7860 perf_swevent_put_recursion_context(rctx
);
7864 perf_tp_event(call
->event
.type
, count
, raw_data
, size
, regs
, head
,
7867 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit
);
7869 void perf_tp_event(u16 event_type
, u64 count
, void *record
, int entry_size
,
7870 struct pt_regs
*regs
, struct hlist_head
*head
, int rctx
,
7871 struct task_struct
*task
)
7873 struct perf_sample_data data
;
7874 struct perf_event
*event
;
7876 struct perf_raw_record raw
= {
7883 perf_sample_data_init(&data
, 0, 0);
7886 perf_trace_buf_update(record
, event_type
);
7888 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
7889 if (perf_tp_event_match(event
, &data
, regs
))
7890 perf_swevent_event(event
, count
, &data
, regs
);
7894 * If we got specified a target task, also iterate its context and
7895 * deliver this event there too.
7897 if (task
&& task
!= current
) {
7898 struct perf_event_context
*ctx
;
7899 struct trace_entry
*entry
= record
;
7902 ctx
= rcu_dereference(task
->perf_event_ctxp
[perf_sw_context
]);
7906 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
7907 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
7909 if (event
->attr
.config
!= entry
->type
)
7911 if (perf_tp_event_match(event
, &data
, regs
))
7912 perf_swevent_event(event
, count
, &data
, regs
);
7918 perf_swevent_put_recursion_context(rctx
);
7920 EXPORT_SYMBOL_GPL(perf_tp_event
);
7922 static void tp_perf_event_destroy(struct perf_event
*event
)
7924 perf_trace_destroy(event
);
7927 static int perf_tp_event_init(struct perf_event
*event
)
7931 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
7935 * no branch sampling for tracepoint events
7937 if (has_branch_stack(event
))
7940 err
= perf_trace_init(event
);
7944 event
->destroy
= tp_perf_event_destroy
;
7949 static struct pmu perf_tracepoint
= {
7950 .task_ctx_nr
= perf_sw_context
,
7952 .event_init
= perf_tp_event_init
,
7953 .add
= perf_trace_add
,
7954 .del
= perf_trace_del
,
7955 .start
= perf_swevent_start
,
7956 .stop
= perf_swevent_stop
,
7957 .read
= perf_swevent_read
,
7960 static inline void perf_tp_register(void)
7962 perf_pmu_register(&perf_tracepoint
, "tracepoint", PERF_TYPE_TRACEPOINT
);
7965 static void perf_event_free_filter(struct perf_event
*event
)
7967 ftrace_profile_free_filter(event
);
7970 #ifdef CONFIG_BPF_SYSCALL
7971 static void bpf_overflow_handler(struct perf_event
*event
,
7972 struct perf_sample_data
*data
,
7973 struct pt_regs
*regs
)
7975 struct bpf_perf_event_data_kern ctx
= {
7982 if (unlikely(__this_cpu_inc_return(bpf_prog_active
) != 1))
7985 ret
= BPF_PROG_RUN(event
->prog
, &ctx
);
7988 __this_cpu_dec(bpf_prog_active
);
7993 event
->orig_overflow_handler(event
, data
, regs
);
7996 static int perf_event_set_bpf_handler(struct perf_event
*event
, u32 prog_fd
)
7998 struct bpf_prog
*prog
;
8000 if (event
->overflow_handler_context
)
8001 /* hw breakpoint or kernel counter */
8007 prog
= bpf_prog_get_type(prog_fd
, BPF_PROG_TYPE_PERF_EVENT
);
8009 return PTR_ERR(prog
);
8012 event
->orig_overflow_handler
= READ_ONCE(event
->overflow_handler
);
8013 WRITE_ONCE(event
->overflow_handler
, bpf_overflow_handler
);
8017 static void perf_event_free_bpf_handler(struct perf_event
*event
)
8019 struct bpf_prog
*prog
= event
->prog
;
8024 WRITE_ONCE(event
->overflow_handler
, event
->orig_overflow_handler
);
8029 static int perf_event_set_bpf_handler(struct perf_event
*event
, u32 prog_fd
)
8033 static void perf_event_free_bpf_handler(struct perf_event
*event
)
8038 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
)
8040 bool is_kprobe
, is_tracepoint
;
8041 struct bpf_prog
*prog
;
8043 if (event
->attr
.type
== PERF_TYPE_HARDWARE
||
8044 event
->attr
.type
== PERF_TYPE_SOFTWARE
)
8045 return perf_event_set_bpf_handler(event
, prog_fd
);
8047 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
8050 if (event
->tp_event
->prog
)
8053 is_kprobe
= event
->tp_event
->flags
& TRACE_EVENT_FL_UKPROBE
;
8054 is_tracepoint
= event
->tp_event
->flags
& TRACE_EVENT_FL_TRACEPOINT
;
8055 if (!is_kprobe
&& !is_tracepoint
)
8056 /* bpf programs can only be attached to u/kprobe or tracepoint */
8059 prog
= bpf_prog_get(prog_fd
);
8061 return PTR_ERR(prog
);
8063 if ((is_kprobe
&& prog
->type
!= BPF_PROG_TYPE_KPROBE
) ||
8064 (is_tracepoint
&& prog
->type
!= BPF_PROG_TYPE_TRACEPOINT
)) {
8065 /* valid fd, but invalid bpf program type */
8070 if (is_tracepoint
) {
8071 int off
= trace_event_get_offsets(event
->tp_event
);
8073 if (prog
->aux
->max_ctx_offset
> off
) {
8078 event
->tp_event
->prog
= prog
;
8083 static void perf_event_free_bpf_prog(struct perf_event
*event
)
8085 struct bpf_prog
*prog
;
8087 perf_event_free_bpf_handler(event
);
8089 if (!event
->tp_event
)
8092 prog
= event
->tp_event
->prog
;
8094 event
->tp_event
->prog
= NULL
;
8101 static inline void perf_tp_register(void)
8105 static void perf_event_free_filter(struct perf_event
*event
)
8109 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
)
8114 static void perf_event_free_bpf_prog(struct perf_event
*event
)
8117 #endif /* CONFIG_EVENT_TRACING */
8119 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8120 void perf_bp_event(struct perf_event
*bp
, void *data
)
8122 struct perf_sample_data sample
;
8123 struct pt_regs
*regs
= data
;
8125 perf_sample_data_init(&sample
, bp
->attr
.bp_addr
, 0);
8127 if (!bp
->hw
.state
&& !perf_exclude_event(bp
, regs
))
8128 perf_swevent_event(bp
, 1, &sample
, regs
);
8133 * Allocate a new address filter
8135 static struct perf_addr_filter
*
8136 perf_addr_filter_new(struct perf_event
*event
, struct list_head
*filters
)
8138 int node
= cpu_to_node(event
->cpu
== -1 ? 0 : event
->cpu
);
8139 struct perf_addr_filter
*filter
;
8141 filter
= kzalloc_node(sizeof(*filter
), GFP_KERNEL
, node
);
8145 INIT_LIST_HEAD(&filter
->entry
);
8146 list_add_tail(&filter
->entry
, filters
);
8151 static void free_filters_list(struct list_head
*filters
)
8153 struct perf_addr_filter
*filter
, *iter
;
8155 list_for_each_entry_safe(filter
, iter
, filters
, entry
) {
8157 iput(filter
->inode
);
8158 list_del(&filter
->entry
);
8164 * Free existing address filters and optionally install new ones
8166 static void perf_addr_filters_splice(struct perf_event
*event
,
8167 struct list_head
*head
)
8169 unsigned long flags
;
8172 if (!has_addr_filter(event
))
8175 /* don't bother with children, they don't have their own filters */
8179 raw_spin_lock_irqsave(&event
->addr_filters
.lock
, flags
);
8181 list_splice_init(&event
->addr_filters
.list
, &list
);
8183 list_splice(head
, &event
->addr_filters
.list
);
8185 raw_spin_unlock_irqrestore(&event
->addr_filters
.lock
, flags
);
8187 free_filters_list(&list
);
8191 * Scan through mm's vmas and see if one of them matches the
8192 * @filter; if so, adjust filter's address range.
8193 * Called with mm::mmap_sem down for reading.
8195 static unsigned long perf_addr_filter_apply(struct perf_addr_filter
*filter
,
8196 struct mm_struct
*mm
)
8198 struct vm_area_struct
*vma
;
8200 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
8201 struct file
*file
= vma
->vm_file
;
8202 unsigned long off
= vma
->vm_pgoff
<< PAGE_SHIFT
;
8203 unsigned long vma_size
= vma
->vm_end
- vma
->vm_start
;
8208 if (!perf_addr_filter_match(filter
, file
, off
, vma_size
))
8211 return vma
->vm_start
;
8218 * Update event's address range filters based on the
8219 * task's existing mappings, if any.
8221 static void perf_event_addr_filters_apply(struct perf_event
*event
)
8223 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
8224 struct task_struct
*task
= READ_ONCE(event
->ctx
->task
);
8225 struct perf_addr_filter
*filter
;
8226 struct mm_struct
*mm
= NULL
;
8227 unsigned int count
= 0;
8228 unsigned long flags
;
8231 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8232 * will stop on the parent's child_mutex that our caller is also holding
8234 if (task
== TASK_TOMBSTONE
)
8237 if (!ifh
->nr_file_filters
)
8240 mm
= get_task_mm(event
->ctx
->task
);
8244 down_read(&mm
->mmap_sem
);
8246 raw_spin_lock_irqsave(&ifh
->lock
, flags
);
8247 list_for_each_entry(filter
, &ifh
->list
, entry
) {
8248 event
->addr_filters_offs
[count
] = 0;
8251 * Adjust base offset if the filter is associated to a binary
8252 * that needs to be mapped:
8255 event
->addr_filters_offs
[count
] =
8256 perf_addr_filter_apply(filter
, mm
);
8261 event
->addr_filters_gen
++;
8262 raw_spin_unlock_irqrestore(&ifh
->lock
, flags
);
8264 up_read(&mm
->mmap_sem
);
8269 perf_event_stop(event
, 1);
8273 * Address range filtering: limiting the data to certain
8274 * instruction address ranges. Filters are ioctl()ed to us from
8275 * userspace as ascii strings.
8277 * Filter string format:
8280 * where ACTION is one of the
8281 * * "filter": limit the trace to this region
8282 * * "start": start tracing from this address
8283 * * "stop": stop tracing at this address/region;
8285 * * for kernel addresses: <start address>[/<size>]
8286 * * for object files: <start address>[/<size>]@</path/to/object/file>
8288 * if <size> is not specified, the range is treated as a single address.
8302 IF_STATE_ACTION
= 0,
8307 static const match_table_t if_tokens
= {
8308 { IF_ACT_FILTER
, "filter" },
8309 { IF_ACT_START
, "start" },
8310 { IF_ACT_STOP
, "stop" },
8311 { IF_SRC_FILE
, "%u/%u@%s" },
8312 { IF_SRC_KERNEL
, "%u/%u" },
8313 { IF_SRC_FILEADDR
, "%u@%s" },
8314 { IF_SRC_KERNELADDR
, "%u" },
8315 { IF_ACT_NONE
, NULL
},
8319 * Address filter string parser
8322 perf_event_parse_addr_filter(struct perf_event
*event
, char *fstr
,
8323 struct list_head
*filters
)
8325 struct perf_addr_filter
*filter
= NULL
;
8326 char *start
, *orig
, *filename
= NULL
;
8328 substring_t args
[MAX_OPT_ARGS
];
8329 int state
= IF_STATE_ACTION
, token
;
8330 unsigned int kernel
= 0;
8333 orig
= fstr
= kstrdup(fstr
, GFP_KERNEL
);
8337 while ((start
= strsep(&fstr
, " ,\n")) != NULL
) {
8343 /* filter definition begins */
8344 if (state
== IF_STATE_ACTION
) {
8345 filter
= perf_addr_filter_new(event
, filters
);
8350 token
= match_token(start
, if_tokens
, args
);
8357 if (state
!= IF_STATE_ACTION
)
8360 state
= IF_STATE_SOURCE
;
8363 case IF_SRC_KERNELADDR
:
8367 case IF_SRC_FILEADDR
:
8369 if (state
!= IF_STATE_SOURCE
)
8372 if (token
== IF_SRC_FILE
|| token
== IF_SRC_KERNEL
)
8376 ret
= kstrtoul(args
[0].from
, 0, &filter
->offset
);
8380 if (filter
->range
) {
8382 ret
= kstrtoul(args
[1].from
, 0, &filter
->size
);
8387 if (token
== IF_SRC_FILE
|| token
== IF_SRC_FILEADDR
) {
8388 int fpos
= filter
->range
? 2 : 1;
8390 filename
= match_strdup(&args
[fpos
]);
8397 state
= IF_STATE_END
;
8405 * Filter definition is fully parsed, validate and install it.
8406 * Make sure that it doesn't contradict itself or the event's
8409 if (state
== IF_STATE_END
) {
8411 if (kernel
&& event
->attr
.exclude_kernel
)
8419 * For now, we only support file-based filters
8420 * in per-task events; doing so for CPU-wide
8421 * events requires additional context switching
8422 * trickery, since same object code will be
8423 * mapped at different virtual addresses in
8424 * different processes.
8427 if (!event
->ctx
->task
)
8428 goto fail_free_name
;
8430 /* look up the path and grab its inode */
8431 ret
= kern_path(filename
, LOOKUP_FOLLOW
, &path
);
8433 goto fail_free_name
;
8435 filter
->inode
= igrab(d_inode(path
.dentry
));
8441 if (!filter
->inode
||
8442 !S_ISREG(filter
->inode
->i_mode
))
8443 /* free_filters_list() will iput() */
8446 event
->addr_filters
.nr_file_filters
++;
8449 /* ready to consume more filters */
8450 state
= IF_STATE_ACTION
;
8455 if (state
!= IF_STATE_ACTION
)
8465 free_filters_list(filters
);
8472 perf_event_set_addr_filter(struct perf_event
*event
, char *filter_str
)
8478 * Since this is called in perf_ioctl() path, we're already holding
8481 lockdep_assert_held(&event
->ctx
->mutex
);
8483 if (WARN_ON_ONCE(event
->parent
))
8486 ret
= perf_event_parse_addr_filter(event
, filter_str
, &filters
);
8488 goto fail_clear_files
;
8490 ret
= event
->pmu
->addr_filters_validate(&filters
);
8492 goto fail_free_filters
;
8494 /* remove existing filters, if any */
8495 perf_addr_filters_splice(event
, &filters
);
8497 /* install new filters */
8498 perf_event_for_each_child(event
, perf_event_addr_filters_apply
);
8503 free_filters_list(&filters
);
8506 event
->addr_filters
.nr_file_filters
= 0;
8511 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
8516 if ((event
->attr
.type
!= PERF_TYPE_TRACEPOINT
||
8517 !IS_ENABLED(CONFIG_EVENT_TRACING
)) &&
8518 !has_addr_filter(event
))
8521 filter_str
= strndup_user(arg
, PAGE_SIZE
);
8522 if (IS_ERR(filter_str
))
8523 return PTR_ERR(filter_str
);
8525 if (IS_ENABLED(CONFIG_EVENT_TRACING
) &&
8526 event
->attr
.type
== PERF_TYPE_TRACEPOINT
)
8527 ret
= ftrace_profile_set_filter(event
, event
->attr
.config
,
8529 else if (has_addr_filter(event
))
8530 ret
= perf_event_set_addr_filter(event
, filter_str
);
8537 * hrtimer based swevent callback
8540 static enum hrtimer_restart
perf_swevent_hrtimer(struct hrtimer
*hrtimer
)
8542 enum hrtimer_restart ret
= HRTIMER_RESTART
;
8543 struct perf_sample_data data
;
8544 struct pt_regs
*regs
;
8545 struct perf_event
*event
;
8548 event
= container_of(hrtimer
, struct perf_event
, hw
.hrtimer
);
8550 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
8551 return HRTIMER_NORESTART
;
8553 event
->pmu
->read(event
);
8555 perf_sample_data_init(&data
, 0, event
->hw
.last_period
);
8556 regs
= get_irq_regs();
8558 if (regs
&& !perf_exclude_event(event
, regs
)) {
8559 if (!(event
->attr
.exclude_idle
&& is_idle_task(current
)))
8560 if (__perf_event_overflow(event
, 1, &data
, regs
))
8561 ret
= HRTIMER_NORESTART
;
8564 period
= max_t(u64
, 10000, event
->hw
.sample_period
);
8565 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
8570 static void perf_swevent_start_hrtimer(struct perf_event
*event
)
8572 struct hw_perf_event
*hwc
= &event
->hw
;
8575 if (!is_sampling_event(event
))
8578 period
= local64_read(&hwc
->period_left
);
8583 local64_set(&hwc
->period_left
, 0);
8585 period
= max_t(u64
, 10000, hwc
->sample_period
);
8587 hrtimer_start(&hwc
->hrtimer
, ns_to_ktime(period
),
8588 HRTIMER_MODE_REL_PINNED
);
8591 static void perf_swevent_cancel_hrtimer(struct perf_event
*event
)
8593 struct hw_perf_event
*hwc
= &event
->hw
;
8595 if (is_sampling_event(event
)) {
8596 ktime_t remaining
= hrtimer_get_remaining(&hwc
->hrtimer
);
8597 local64_set(&hwc
->period_left
, ktime_to_ns(remaining
));
8599 hrtimer_cancel(&hwc
->hrtimer
);
8603 static void perf_swevent_init_hrtimer(struct perf_event
*event
)
8605 struct hw_perf_event
*hwc
= &event
->hw
;
8607 if (!is_sampling_event(event
))
8610 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
8611 hwc
->hrtimer
.function
= perf_swevent_hrtimer
;
8614 * Since hrtimers have a fixed rate, we can do a static freq->period
8615 * mapping and avoid the whole period adjust feedback stuff.
8617 if (event
->attr
.freq
) {
8618 long freq
= event
->attr
.sample_freq
;
8620 event
->attr
.sample_period
= NSEC_PER_SEC
/ freq
;
8621 hwc
->sample_period
= event
->attr
.sample_period
;
8622 local64_set(&hwc
->period_left
, hwc
->sample_period
);
8623 hwc
->last_period
= hwc
->sample_period
;
8624 event
->attr
.freq
= 0;
8629 * Software event: cpu wall time clock
8632 static void cpu_clock_event_update(struct perf_event
*event
)
8637 now
= local_clock();
8638 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
8639 local64_add(now
- prev
, &event
->count
);
8642 static void cpu_clock_event_start(struct perf_event
*event
, int flags
)
8644 local64_set(&event
->hw
.prev_count
, local_clock());
8645 perf_swevent_start_hrtimer(event
);
8648 static void cpu_clock_event_stop(struct perf_event
*event
, int flags
)
8650 perf_swevent_cancel_hrtimer(event
);
8651 cpu_clock_event_update(event
);
8654 static int cpu_clock_event_add(struct perf_event
*event
, int flags
)
8656 if (flags
& PERF_EF_START
)
8657 cpu_clock_event_start(event
, flags
);
8658 perf_event_update_userpage(event
);
8663 static void cpu_clock_event_del(struct perf_event
*event
, int flags
)
8665 cpu_clock_event_stop(event
, flags
);
8668 static void cpu_clock_event_read(struct perf_event
*event
)
8670 cpu_clock_event_update(event
);
8673 static int cpu_clock_event_init(struct perf_event
*event
)
8675 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
8678 if (event
->attr
.config
!= PERF_COUNT_SW_CPU_CLOCK
)
8682 * no branch sampling for software events
8684 if (has_branch_stack(event
))
8687 perf_swevent_init_hrtimer(event
);
8692 static struct pmu perf_cpu_clock
= {
8693 .task_ctx_nr
= perf_sw_context
,
8695 .capabilities
= PERF_PMU_CAP_NO_NMI
,
8697 .event_init
= cpu_clock_event_init
,
8698 .add
= cpu_clock_event_add
,
8699 .del
= cpu_clock_event_del
,
8700 .start
= cpu_clock_event_start
,
8701 .stop
= cpu_clock_event_stop
,
8702 .read
= cpu_clock_event_read
,
8706 * Software event: task time clock
8709 static void task_clock_event_update(struct perf_event
*event
, u64 now
)
8714 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
8716 local64_add(delta
, &event
->count
);
8719 static void task_clock_event_start(struct perf_event
*event
, int flags
)
8721 local64_set(&event
->hw
.prev_count
, event
->ctx
->time
);
8722 perf_swevent_start_hrtimer(event
);
8725 static void task_clock_event_stop(struct perf_event
*event
, int flags
)
8727 perf_swevent_cancel_hrtimer(event
);
8728 task_clock_event_update(event
, event
->ctx
->time
);
8731 static int task_clock_event_add(struct perf_event
*event
, int flags
)
8733 if (flags
& PERF_EF_START
)
8734 task_clock_event_start(event
, flags
);
8735 perf_event_update_userpage(event
);
8740 static void task_clock_event_del(struct perf_event
*event
, int flags
)
8742 task_clock_event_stop(event
, PERF_EF_UPDATE
);
8745 static void task_clock_event_read(struct perf_event
*event
)
8747 u64 now
= perf_clock();
8748 u64 delta
= now
- event
->ctx
->timestamp
;
8749 u64 time
= event
->ctx
->time
+ delta
;
8751 task_clock_event_update(event
, time
);
8754 static int task_clock_event_init(struct perf_event
*event
)
8756 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
8759 if (event
->attr
.config
!= PERF_COUNT_SW_TASK_CLOCK
)
8763 * no branch sampling for software events
8765 if (has_branch_stack(event
))
8768 perf_swevent_init_hrtimer(event
);
8773 static struct pmu perf_task_clock
= {
8774 .task_ctx_nr
= perf_sw_context
,
8776 .capabilities
= PERF_PMU_CAP_NO_NMI
,
8778 .event_init
= task_clock_event_init
,
8779 .add
= task_clock_event_add
,
8780 .del
= task_clock_event_del
,
8781 .start
= task_clock_event_start
,
8782 .stop
= task_clock_event_stop
,
8783 .read
= task_clock_event_read
,
8786 static void perf_pmu_nop_void(struct pmu
*pmu
)
8790 static void perf_pmu_nop_txn(struct pmu
*pmu
, unsigned int flags
)
8794 static int perf_pmu_nop_int(struct pmu
*pmu
)
8799 static DEFINE_PER_CPU(unsigned int, nop_txn_flags
);
8801 static void perf_pmu_start_txn(struct pmu
*pmu
, unsigned int flags
)
8803 __this_cpu_write(nop_txn_flags
, flags
);
8805 if (flags
& ~PERF_PMU_TXN_ADD
)
8808 perf_pmu_disable(pmu
);
8811 static int perf_pmu_commit_txn(struct pmu
*pmu
)
8813 unsigned int flags
= __this_cpu_read(nop_txn_flags
);
8815 __this_cpu_write(nop_txn_flags
, 0);
8817 if (flags
& ~PERF_PMU_TXN_ADD
)
8820 perf_pmu_enable(pmu
);
8824 static void perf_pmu_cancel_txn(struct pmu
*pmu
)
8826 unsigned int flags
= __this_cpu_read(nop_txn_flags
);
8828 __this_cpu_write(nop_txn_flags
, 0);
8830 if (flags
& ~PERF_PMU_TXN_ADD
)
8833 perf_pmu_enable(pmu
);
8836 static int perf_event_idx_default(struct perf_event
*event
)
8842 * Ensures all contexts with the same task_ctx_nr have the same
8843 * pmu_cpu_context too.
8845 static struct perf_cpu_context __percpu
*find_pmu_context(int ctxn
)
8852 list_for_each_entry(pmu
, &pmus
, entry
) {
8853 if (pmu
->task_ctx_nr
== ctxn
)
8854 return pmu
->pmu_cpu_context
;
8860 static void free_pmu_context(struct pmu
*pmu
)
8862 mutex_lock(&pmus_lock
);
8863 free_percpu(pmu
->pmu_cpu_context
);
8864 mutex_unlock(&pmus_lock
);
8868 * Let userspace know that this PMU supports address range filtering:
8870 static ssize_t
nr_addr_filters_show(struct device
*dev
,
8871 struct device_attribute
*attr
,
8874 struct pmu
*pmu
= dev_get_drvdata(dev
);
8876 return snprintf(page
, PAGE_SIZE
- 1, "%d\n", pmu
->nr_addr_filters
);
8878 DEVICE_ATTR_RO(nr_addr_filters
);
8880 static struct idr pmu_idr
;
8883 type_show(struct device
*dev
, struct device_attribute
*attr
, char *page
)
8885 struct pmu
*pmu
= dev_get_drvdata(dev
);
8887 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->type
);
8889 static DEVICE_ATTR_RO(type
);
8892 perf_event_mux_interval_ms_show(struct device
*dev
,
8893 struct device_attribute
*attr
,
8896 struct pmu
*pmu
= dev_get_drvdata(dev
);
8898 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->hrtimer_interval_ms
);
8901 static DEFINE_MUTEX(mux_interval_mutex
);
8904 perf_event_mux_interval_ms_store(struct device
*dev
,
8905 struct device_attribute
*attr
,
8906 const char *buf
, size_t count
)
8908 struct pmu
*pmu
= dev_get_drvdata(dev
);
8909 int timer
, cpu
, ret
;
8911 ret
= kstrtoint(buf
, 0, &timer
);
8918 /* same value, noting to do */
8919 if (timer
== pmu
->hrtimer_interval_ms
)
8922 mutex_lock(&mux_interval_mutex
);
8923 pmu
->hrtimer_interval_ms
= timer
;
8925 /* update all cpuctx for this PMU */
8927 for_each_online_cpu(cpu
) {
8928 struct perf_cpu_context
*cpuctx
;
8929 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
8930 cpuctx
->hrtimer_interval
= ns_to_ktime(NSEC_PER_MSEC
* timer
);
8932 cpu_function_call(cpu
,
8933 (remote_function_f
)perf_mux_hrtimer_restart
, cpuctx
);
8936 mutex_unlock(&mux_interval_mutex
);
8940 static DEVICE_ATTR_RW(perf_event_mux_interval_ms
);
8942 static struct attribute
*pmu_dev_attrs
[] = {
8943 &dev_attr_type
.attr
,
8944 &dev_attr_perf_event_mux_interval_ms
.attr
,
8947 ATTRIBUTE_GROUPS(pmu_dev
);
8949 static int pmu_bus_running
;
8950 static struct bus_type pmu_bus
= {
8951 .name
= "event_source",
8952 .dev_groups
= pmu_dev_groups
,
8955 static void pmu_dev_release(struct device
*dev
)
8960 static int pmu_dev_alloc(struct pmu
*pmu
)
8964 pmu
->dev
= kzalloc(sizeof(struct device
), GFP_KERNEL
);
8968 pmu
->dev
->groups
= pmu
->attr_groups
;
8969 device_initialize(pmu
->dev
);
8970 ret
= dev_set_name(pmu
->dev
, "%s", pmu
->name
);
8974 dev_set_drvdata(pmu
->dev
, pmu
);
8975 pmu
->dev
->bus
= &pmu_bus
;
8976 pmu
->dev
->release
= pmu_dev_release
;
8977 ret
= device_add(pmu
->dev
);
8981 /* For PMUs with address filters, throw in an extra attribute: */
8982 if (pmu
->nr_addr_filters
)
8983 ret
= device_create_file(pmu
->dev
, &dev_attr_nr_addr_filters
);
8992 device_del(pmu
->dev
);
8995 put_device(pmu
->dev
);
8999 static struct lock_class_key cpuctx_mutex
;
9000 static struct lock_class_key cpuctx_lock
;
9002 int perf_pmu_register(struct pmu
*pmu
, const char *name
, int type
)
9006 mutex_lock(&pmus_lock
);
9008 pmu
->pmu_disable_count
= alloc_percpu(int);
9009 if (!pmu
->pmu_disable_count
)
9018 type
= idr_alloc(&pmu_idr
, pmu
, PERF_TYPE_MAX
, 0, GFP_KERNEL
);
9026 if (pmu_bus_running
) {
9027 ret
= pmu_dev_alloc(pmu
);
9033 if (pmu
->task_ctx_nr
== perf_hw_context
) {
9034 static int hw_context_taken
= 0;
9037 * Other than systems with heterogeneous CPUs, it never makes
9038 * sense for two PMUs to share perf_hw_context. PMUs which are
9039 * uncore must use perf_invalid_context.
9041 if (WARN_ON_ONCE(hw_context_taken
&&
9042 !(pmu
->capabilities
& PERF_PMU_CAP_HETEROGENEOUS_CPUS
)))
9043 pmu
->task_ctx_nr
= perf_invalid_context
;
9045 hw_context_taken
= 1;
9048 pmu
->pmu_cpu_context
= find_pmu_context(pmu
->task_ctx_nr
);
9049 if (pmu
->pmu_cpu_context
)
9050 goto got_cpu_context
;
9053 pmu
->pmu_cpu_context
= alloc_percpu(struct perf_cpu_context
);
9054 if (!pmu
->pmu_cpu_context
)
9057 for_each_possible_cpu(cpu
) {
9058 struct perf_cpu_context
*cpuctx
;
9060 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
9061 __perf_event_init_context(&cpuctx
->ctx
);
9062 lockdep_set_class(&cpuctx
->ctx
.mutex
, &cpuctx_mutex
);
9063 lockdep_set_class(&cpuctx
->ctx
.lock
, &cpuctx_lock
);
9064 cpuctx
->ctx
.pmu
= pmu
;
9065 cpuctx
->online
= cpumask_test_cpu(cpu
, perf_online_mask
);
9067 __perf_mux_hrtimer_init(cpuctx
, cpu
);
9071 if (!pmu
->start_txn
) {
9072 if (pmu
->pmu_enable
) {
9074 * If we have pmu_enable/pmu_disable calls, install
9075 * transaction stubs that use that to try and batch
9076 * hardware accesses.
9078 pmu
->start_txn
= perf_pmu_start_txn
;
9079 pmu
->commit_txn
= perf_pmu_commit_txn
;
9080 pmu
->cancel_txn
= perf_pmu_cancel_txn
;
9082 pmu
->start_txn
= perf_pmu_nop_txn
;
9083 pmu
->commit_txn
= perf_pmu_nop_int
;
9084 pmu
->cancel_txn
= perf_pmu_nop_void
;
9088 if (!pmu
->pmu_enable
) {
9089 pmu
->pmu_enable
= perf_pmu_nop_void
;
9090 pmu
->pmu_disable
= perf_pmu_nop_void
;
9093 if (!pmu
->event_idx
)
9094 pmu
->event_idx
= perf_event_idx_default
;
9096 list_add_rcu(&pmu
->entry
, &pmus
);
9097 atomic_set(&pmu
->exclusive_cnt
, 0);
9100 mutex_unlock(&pmus_lock
);
9105 device_del(pmu
->dev
);
9106 put_device(pmu
->dev
);
9109 if (pmu
->type
>= PERF_TYPE_MAX
)
9110 idr_remove(&pmu_idr
, pmu
->type
);
9113 free_percpu(pmu
->pmu_disable_count
);
9116 EXPORT_SYMBOL_GPL(perf_pmu_register
);
9118 void perf_pmu_unregister(struct pmu
*pmu
)
9122 mutex_lock(&pmus_lock
);
9123 remove_device
= pmu_bus_running
;
9124 list_del_rcu(&pmu
->entry
);
9125 mutex_unlock(&pmus_lock
);
9128 * We dereference the pmu list under both SRCU and regular RCU, so
9129 * synchronize against both of those.
9131 synchronize_srcu(&pmus_srcu
);
9134 free_percpu(pmu
->pmu_disable_count
);
9135 if (pmu
->type
>= PERF_TYPE_MAX
)
9136 idr_remove(&pmu_idr
, pmu
->type
);
9137 if (remove_device
) {
9138 if (pmu
->nr_addr_filters
)
9139 device_remove_file(pmu
->dev
, &dev_attr_nr_addr_filters
);
9140 device_del(pmu
->dev
);
9141 put_device(pmu
->dev
);
9143 free_pmu_context(pmu
);
9145 EXPORT_SYMBOL_GPL(perf_pmu_unregister
);
9147 static int perf_try_init_event(struct pmu
*pmu
, struct perf_event
*event
)
9149 struct perf_event_context
*ctx
= NULL
;
9152 if (!try_module_get(pmu
->module
))
9155 if (event
->group_leader
!= event
) {
9157 * This ctx->mutex can nest when we're called through
9158 * inheritance. See the perf_event_ctx_lock_nested() comment.
9160 ctx
= perf_event_ctx_lock_nested(event
->group_leader
,
9161 SINGLE_DEPTH_NESTING
);
9166 ret
= pmu
->event_init(event
);
9169 perf_event_ctx_unlock(event
->group_leader
, ctx
);
9172 module_put(pmu
->module
);
9177 static struct pmu
*perf_init_event(struct perf_event
*event
)
9183 idx
= srcu_read_lock(&pmus_srcu
);
9185 /* Try parent's PMU first: */
9186 if (event
->parent
&& event
->parent
->pmu
) {
9187 pmu
= event
->parent
->pmu
;
9188 ret
= perf_try_init_event(pmu
, event
);
9194 pmu
= idr_find(&pmu_idr
, event
->attr
.type
);
9197 ret
= perf_try_init_event(pmu
, event
);
9203 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
9204 ret
= perf_try_init_event(pmu
, event
);
9208 if (ret
!= -ENOENT
) {
9213 pmu
= ERR_PTR(-ENOENT
);
9215 srcu_read_unlock(&pmus_srcu
, idx
);
9220 static void attach_sb_event(struct perf_event
*event
)
9222 struct pmu_event_list
*pel
= per_cpu_ptr(&pmu_sb_events
, event
->cpu
);
9224 raw_spin_lock(&pel
->lock
);
9225 list_add_rcu(&event
->sb_list
, &pel
->list
);
9226 raw_spin_unlock(&pel
->lock
);
9230 * We keep a list of all !task (and therefore per-cpu) events
9231 * that need to receive side-band records.
9233 * This avoids having to scan all the various PMU per-cpu contexts
9236 static void account_pmu_sb_event(struct perf_event
*event
)
9238 if (is_sb_event(event
))
9239 attach_sb_event(event
);
9242 static void account_event_cpu(struct perf_event
*event
, int cpu
)
9247 if (is_cgroup_event(event
))
9248 atomic_inc(&per_cpu(perf_cgroup_events
, cpu
));
9251 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9252 static void account_freq_event_nohz(void)
9254 #ifdef CONFIG_NO_HZ_FULL
9255 /* Lock so we don't race with concurrent unaccount */
9256 spin_lock(&nr_freq_lock
);
9257 if (atomic_inc_return(&nr_freq_events
) == 1)
9258 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS
);
9259 spin_unlock(&nr_freq_lock
);
9263 static void account_freq_event(void)
9265 if (tick_nohz_full_enabled())
9266 account_freq_event_nohz();
9268 atomic_inc(&nr_freq_events
);
9272 static void account_event(struct perf_event
*event
)
9279 if (event
->attach_state
& PERF_ATTACH_TASK
)
9281 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
9282 atomic_inc(&nr_mmap_events
);
9283 if (event
->attr
.comm
)
9284 atomic_inc(&nr_comm_events
);
9285 if (event
->attr
.namespaces
)
9286 atomic_inc(&nr_namespaces_events
);
9287 if (event
->attr
.task
)
9288 atomic_inc(&nr_task_events
);
9289 if (event
->attr
.freq
)
9290 account_freq_event();
9291 if (event
->attr
.context_switch
) {
9292 atomic_inc(&nr_switch_events
);
9295 if (has_branch_stack(event
))
9297 if (is_cgroup_event(event
))
9301 if (atomic_inc_not_zero(&perf_sched_count
))
9304 mutex_lock(&perf_sched_mutex
);
9305 if (!atomic_read(&perf_sched_count
)) {
9306 static_branch_enable(&perf_sched_events
);
9308 * Guarantee that all CPUs observe they key change and
9309 * call the perf scheduling hooks before proceeding to
9310 * install events that need them.
9312 synchronize_sched();
9315 * Now that we have waited for the sync_sched(), allow further
9316 * increments to by-pass the mutex.
9318 atomic_inc(&perf_sched_count
);
9319 mutex_unlock(&perf_sched_mutex
);
9323 account_event_cpu(event
, event
->cpu
);
9325 account_pmu_sb_event(event
);
9329 * Allocate and initialize a event structure
9331 static struct perf_event
*
9332 perf_event_alloc(struct perf_event_attr
*attr
, int cpu
,
9333 struct task_struct
*task
,
9334 struct perf_event
*group_leader
,
9335 struct perf_event
*parent_event
,
9336 perf_overflow_handler_t overflow_handler
,
9337 void *context
, int cgroup_fd
)
9340 struct perf_event
*event
;
9341 struct hw_perf_event
*hwc
;
9344 if ((unsigned)cpu
>= nr_cpu_ids
) {
9345 if (!task
|| cpu
!= -1)
9346 return ERR_PTR(-EINVAL
);
9349 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
9351 return ERR_PTR(-ENOMEM
);
9354 * Single events are their own group leaders, with an
9355 * empty sibling list:
9358 group_leader
= event
;
9360 mutex_init(&event
->child_mutex
);
9361 INIT_LIST_HEAD(&event
->child_list
);
9363 INIT_LIST_HEAD(&event
->group_entry
);
9364 INIT_LIST_HEAD(&event
->event_entry
);
9365 INIT_LIST_HEAD(&event
->sibling_list
);
9366 INIT_LIST_HEAD(&event
->rb_entry
);
9367 INIT_LIST_HEAD(&event
->active_entry
);
9368 INIT_LIST_HEAD(&event
->addr_filters
.list
);
9369 INIT_HLIST_NODE(&event
->hlist_entry
);
9372 init_waitqueue_head(&event
->waitq
);
9373 init_irq_work(&event
->pending
, perf_pending_event
);
9375 mutex_init(&event
->mmap_mutex
);
9376 raw_spin_lock_init(&event
->addr_filters
.lock
);
9378 atomic_long_set(&event
->refcount
, 1);
9380 event
->attr
= *attr
;
9381 event
->group_leader
= group_leader
;
9385 event
->parent
= parent_event
;
9387 event
->ns
= get_pid_ns(task_active_pid_ns(current
));
9388 event
->id
= atomic64_inc_return(&perf_event_id
);
9390 event
->state
= PERF_EVENT_STATE_INACTIVE
;
9393 event
->attach_state
= PERF_ATTACH_TASK
;
9395 * XXX pmu::event_init needs to know what task to account to
9396 * and we cannot use the ctx information because we need the
9397 * pmu before we get a ctx.
9399 event
->hw
.target
= task
;
9402 event
->clock
= &local_clock
;
9404 event
->clock
= parent_event
->clock
;
9406 if (!overflow_handler
&& parent_event
) {
9407 overflow_handler
= parent_event
->overflow_handler
;
9408 context
= parent_event
->overflow_handler_context
;
9409 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9410 if (overflow_handler
== bpf_overflow_handler
) {
9411 struct bpf_prog
*prog
= bpf_prog_inc(parent_event
->prog
);
9414 err
= PTR_ERR(prog
);
9418 event
->orig_overflow_handler
=
9419 parent_event
->orig_overflow_handler
;
9424 if (overflow_handler
) {
9425 event
->overflow_handler
= overflow_handler
;
9426 event
->overflow_handler_context
= context
;
9427 } else if (is_write_backward(event
)){
9428 event
->overflow_handler
= perf_event_output_backward
;
9429 event
->overflow_handler_context
= NULL
;
9431 event
->overflow_handler
= perf_event_output_forward
;
9432 event
->overflow_handler_context
= NULL
;
9435 perf_event__state_init(event
);
9440 hwc
->sample_period
= attr
->sample_period
;
9441 if (attr
->freq
&& attr
->sample_freq
)
9442 hwc
->sample_period
= 1;
9443 hwc
->last_period
= hwc
->sample_period
;
9445 local64_set(&hwc
->period_left
, hwc
->sample_period
);
9448 * We currently do not support PERF_SAMPLE_READ on inherited events.
9449 * See perf_output_read().
9451 if (attr
->inherit
&& (attr
->sample_type
& PERF_SAMPLE_READ
))
9454 if (!has_branch_stack(event
))
9455 event
->attr
.branch_sample_type
= 0;
9457 if (cgroup_fd
!= -1) {
9458 err
= perf_cgroup_connect(cgroup_fd
, event
, attr
, group_leader
);
9463 pmu
= perf_init_event(event
);
9469 err
= exclusive_event_init(event
);
9473 if (has_addr_filter(event
)) {
9474 event
->addr_filters_offs
= kcalloc(pmu
->nr_addr_filters
,
9475 sizeof(unsigned long),
9477 if (!event
->addr_filters_offs
) {
9482 /* force hw sync on the address filters */
9483 event
->addr_filters_gen
= 1;
9486 if (!event
->parent
) {
9487 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
) {
9488 err
= get_callchain_buffers(attr
->sample_max_stack
);
9490 goto err_addr_filters
;
9494 /* symmetric to unaccount_event() in _free_event() */
9495 account_event(event
);
9500 kfree(event
->addr_filters_offs
);
9503 exclusive_event_destroy(event
);
9507 event
->destroy(event
);
9508 module_put(pmu
->module
);
9510 if (is_cgroup_event(event
))
9511 perf_detach_cgroup(event
);
9513 put_pid_ns(event
->ns
);
9516 return ERR_PTR(err
);
9519 static int perf_copy_attr(struct perf_event_attr __user
*uattr
,
9520 struct perf_event_attr
*attr
)
9525 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
9529 * zero the full structure, so that a short copy will be nice.
9531 memset(attr
, 0, sizeof(*attr
));
9533 ret
= get_user(size
, &uattr
->size
);
9537 if (size
> PAGE_SIZE
) /* silly large */
9540 if (!size
) /* abi compat */
9541 size
= PERF_ATTR_SIZE_VER0
;
9543 if (size
< PERF_ATTR_SIZE_VER0
)
9547 * If we're handed a bigger struct than we know of,
9548 * ensure all the unknown bits are 0 - i.e. new
9549 * user-space does not rely on any kernel feature
9550 * extensions we dont know about yet.
9552 if (size
> sizeof(*attr
)) {
9553 unsigned char __user
*addr
;
9554 unsigned char __user
*end
;
9557 addr
= (void __user
*)uattr
+ sizeof(*attr
);
9558 end
= (void __user
*)uattr
+ size
;
9560 for (; addr
< end
; addr
++) {
9561 ret
= get_user(val
, addr
);
9567 size
= sizeof(*attr
);
9570 ret
= copy_from_user(attr
, uattr
, size
);
9574 if (attr
->__reserved_1
)
9577 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
9580 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
9583 if (attr
->sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
9584 u64 mask
= attr
->branch_sample_type
;
9586 /* only using defined bits */
9587 if (mask
& ~(PERF_SAMPLE_BRANCH_MAX
-1))
9590 /* at least one branch bit must be set */
9591 if (!(mask
& ~PERF_SAMPLE_BRANCH_PLM_ALL
))
9594 /* propagate priv level, when not set for branch */
9595 if (!(mask
& PERF_SAMPLE_BRANCH_PLM_ALL
)) {
9597 /* exclude_kernel checked on syscall entry */
9598 if (!attr
->exclude_kernel
)
9599 mask
|= PERF_SAMPLE_BRANCH_KERNEL
;
9601 if (!attr
->exclude_user
)
9602 mask
|= PERF_SAMPLE_BRANCH_USER
;
9604 if (!attr
->exclude_hv
)
9605 mask
|= PERF_SAMPLE_BRANCH_HV
;
9607 * adjust user setting (for HW filter setup)
9609 attr
->branch_sample_type
= mask
;
9611 /* privileged levels capture (kernel, hv): check permissions */
9612 if ((mask
& PERF_SAMPLE_BRANCH_PERM_PLM
)
9613 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
9617 if (attr
->sample_type
& PERF_SAMPLE_REGS_USER
) {
9618 ret
= perf_reg_validate(attr
->sample_regs_user
);
9623 if (attr
->sample_type
& PERF_SAMPLE_STACK_USER
) {
9624 if (!arch_perf_have_user_stack_dump())
9628 * We have __u32 type for the size, but so far
9629 * we can only use __u16 as maximum due to the
9630 * __u16 sample size limit.
9632 if (attr
->sample_stack_user
>= USHRT_MAX
)
9634 else if (!IS_ALIGNED(attr
->sample_stack_user
, sizeof(u64
)))
9638 if (attr
->sample_type
& PERF_SAMPLE_REGS_INTR
)
9639 ret
= perf_reg_validate(attr
->sample_regs_intr
);
9644 put_user(sizeof(*attr
), &uattr
->size
);
9650 perf_event_set_output(struct perf_event
*event
, struct perf_event
*output_event
)
9652 struct ring_buffer
*rb
= NULL
;
9658 /* don't allow circular references */
9659 if (event
== output_event
)
9663 * Don't allow cross-cpu buffers
9665 if (output_event
->cpu
!= event
->cpu
)
9669 * If its not a per-cpu rb, it must be the same task.
9671 if (output_event
->cpu
== -1 && output_event
->ctx
!= event
->ctx
)
9675 * Mixing clocks in the same buffer is trouble you don't need.
9677 if (output_event
->clock
!= event
->clock
)
9681 * Either writing ring buffer from beginning or from end.
9682 * Mixing is not allowed.
9684 if (is_write_backward(output_event
) != is_write_backward(event
))
9688 * If both events generate aux data, they must be on the same PMU
9690 if (has_aux(event
) && has_aux(output_event
) &&
9691 event
->pmu
!= output_event
->pmu
)
9695 mutex_lock(&event
->mmap_mutex
);
9696 /* Can't redirect output if we've got an active mmap() */
9697 if (atomic_read(&event
->mmap_count
))
9701 /* get the rb we want to redirect to */
9702 rb
= ring_buffer_get(output_event
);
9707 ring_buffer_attach(event
, rb
);
9711 mutex_unlock(&event
->mmap_mutex
);
9717 static void mutex_lock_double(struct mutex
*a
, struct mutex
*b
)
9723 mutex_lock_nested(b
, SINGLE_DEPTH_NESTING
);
9726 static int perf_event_set_clock(struct perf_event
*event
, clockid_t clk_id
)
9728 bool nmi_safe
= false;
9731 case CLOCK_MONOTONIC
:
9732 event
->clock
= &ktime_get_mono_fast_ns
;
9736 case CLOCK_MONOTONIC_RAW
:
9737 event
->clock
= &ktime_get_raw_fast_ns
;
9741 case CLOCK_REALTIME
:
9742 event
->clock
= &ktime_get_real_ns
;
9745 case CLOCK_BOOTTIME
:
9746 event
->clock
= &ktime_get_boot_ns
;
9750 event
->clock
= &ktime_get_tai_ns
;
9757 if (!nmi_safe
&& !(event
->pmu
->capabilities
& PERF_PMU_CAP_NO_NMI
))
9764 * Variation on perf_event_ctx_lock_nested(), except we take two context
9767 static struct perf_event_context
*
9768 __perf_event_ctx_lock_double(struct perf_event
*group_leader
,
9769 struct perf_event_context
*ctx
)
9771 struct perf_event_context
*gctx
;
9775 gctx
= READ_ONCE(group_leader
->ctx
);
9776 if (!atomic_inc_not_zero(&gctx
->refcount
)) {
9782 mutex_lock_double(&gctx
->mutex
, &ctx
->mutex
);
9784 if (group_leader
->ctx
!= gctx
) {
9785 mutex_unlock(&ctx
->mutex
);
9786 mutex_unlock(&gctx
->mutex
);
9795 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9797 * @attr_uptr: event_id type attributes for monitoring/sampling
9800 * @group_fd: group leader event fd
9802 SYSCALL_DEFINE5(perf_event_open
,
9803 struct perf_event_attr __user
*, attr_uptr
,
9804 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
9806 struct perf_event
*group_leader
= NULL
, *output_event
= NULL
;
9807 struct perf_event
*event
, *sibling
;
9808 struct perf_event_attr attr
;
9809 struct perf_event_context
*ctx
, *uninitialized_var(gctx
);
9810 struct file
*event_file
= NULL
;
9811 struct fd group
= {NULL
, 0};
9812 struct task_struct
*task
= NULL
;
9817 int f_flags
= O_RDWR
;
9820 /* for future expandability... */
9821 if (flags
& ~PERF_FLAG_ALL
)
9824 err
= perf_copy_attr(attr_uptr
, &attr
);
9828 if (!attr
.exclude_kernel
) {
9829 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
9833 if (attr
.namespaces
) {
9834 if (!capable(CAP_SYS_ADMIN
))
9839 if (attr
.sample_freq
> sysctl_perf_event_sample_rate
)
9842 if (attr
.sample_period
& (1ULL << 63))
9846 if (!attr
.sample_max_stack
)
9847 attr
.sample_max_stack
= sysctl_perf_event_max_stack
;
9850 * In cgroup mode, the pid argument is used to pass the fd
9851 * opened to the cgroup directory in cgroupfs. The cpu argument
9852 * designates the cpu on which to monitor threads from that
9855 if ((flags
& PERF_FLAG_PID_CGROUP
) && (pid
== -1 || cpu
== -1))
9858 if (flags
& PERF_FLAG_FD_CLOEXEC
)
9859 f_flags
|= O_CLOEXEC
;
9861 event_fd
= get_unused_fd_flags(f_flags
);
9865 if (group_fd
!= -1) {
9866 err
= perf_fget_light(group_fd
, &group
);
9869 group_leader
= group
.file
->private_data
;
9870 if (flags
& PERF_FLAG_FD_OUTPUT
)
9871 output_event
= group_leader
;
9872 if (flags
& PERF_FLAG_FD_NO_GROUP
)
9873 group_leader
= NULL
;
9876 if (pid
!= -1 && !(flags
& PERF_FLAG_PID_CGROUP
)) {
9877 task
= find_lively_task_by_vpid(pid
);
9879 err
= PTR_ERR(task
);
9884 if (task
&& group_leader
&&
9885 group_leader
->attr
.inherit
!= attr
.inherit
) {
9891 err
= mutex_lock_interruptible(&task
->signal
->cred_guard_mutex
);
9896 * Reuse ptrace permission checks for now.
9898 * We must hold cred_guard_mutex across this and any potential
9899 * perf_install_in_context() call for this new event to
9900 * serialize against exec() altering our credentials (and the
9901 * perf_event_exit_task() that could imply).
9904 if (!ptrace_may_access(task
, PTRACE_MODE_READ_REALCREDS
))
9908 if (flags
& PERF_FLAG_PID_CGROUP
)
9911 event
= perf_event_alloc(&attr
, cpu
, task
, group_leader
, NULL
,
9912 NULL
, NULL
, cgroup_fd
);
9913 if (IS_ERR(event
)) {
9914 err
= PTR_ERR(event
);
9918 if (is_sampling_event(event
)) {
9919 if (event
->pmu
->capabilities
& PERF_PMU_CAP_NO_INTERRUPT
) {
9926 * Special case software events and allow them to be part of
9927 * any hardware group.
9931 if (attr
.use_clockid
) {
9932 err
= perf_event_set_clock(event
, attr
.clockid
);
9937 if (pmu
->task_ctx_nr
== perf_sw_context
)
9938 event
->event_caps
|= PERF_EV_CAP_SOFTWARE
;
9941 (is_software_event(event
) != is_software_event(group_leader
))) {
9942 if (is_software_event(event
)) {
9944 * If event and group_leader are not both a software
9945 * event, and event is, then group leader is not.
9947 * Allow the addition of software events to !software
9948 * groups, this is safe because software events never
9951 pmu
= group_leader
->pmu
;
9952 } else if (is_software_event(group_leader
) &&
9953 (group_leader
->group_caps
& PERF_EV_CAP_SOFTWARE
)) {
9955 * In case the group is a pure software group, and we
9956 * try to add a hardware event, move the whole group to
9957 * the hardware context.
9964 * Get the target context (task or percpu):
9966 ctx
= find_get_context(pmu
, task
, event
);
9972 if ((pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
) && group_leader
) {
9978 * Look up the group leader (we will attach this event to it):
9984 * Do not allow a recursive hierarchy (this new sibling
9985 * becoming part of another group-sibling):
9987 if (group_leader
->group_leader
!= group_leader
)
9990 /* All events in a group should have the same clock */
9991 if (group_leader
->clock
!= event
->clock
)
9995 * Do not allow to attach to a group in a different
9996 * task or CPU context:
10000 * Make sure we're both on the same task, or both
10003 if (group_leader
->ctx
->task
!= ctx
->task
)
10007 * Make sure we're both events for the same CPU;
10008 * grouping events for different CPUs is broken; since
10009 * you can never concurrently schedule them anyhow.
10011 if (group_leader
->cpu
!= event
->cpu
)
10014 if (group_leader
->ctx
!= ctx
)
10019 * Only a group leader can be exclusive or pinned
10021 if (attr
.exclusive
|| attr
.pinned
)
10025 if (output_event
) {
10026 err
= perf_event_set_output(event
, output_event
);
10031 event_file
= anon_inode_getfile("[perf_event]", &perf_fops
, event
,
10033 if (IS_ERR(event_file
)) {
10034 err
= PTR_ERR(event_file
);
10040 gctx
= __perf_event_ctx_lock_double(group_leader
, ctx
);
10042 if (gctx
->task
== TASK_TOMBSTONE
) {
10048 * Check if we raced against another sys_perf_event_open() call
10049 * moving the software group underneath us.
10051 if (!(group_leader
->group_caps
& PERF_EV_CAP_SOFTWARE
)) {
10053 * If someone moved the group out from under us, check
10054 * if this new event wound up on the same ctx, if so
10055 * its the regular !move_group case, otherwise fail.
10061 perf_event_ctx_unlock(group_leader
, gctx
);
10066 mutex_lock(&ctx
->mutex
);
10069 if (ctx
->task
== TASK_TOMBSTONE
) {
10074 if (!perf_event_validate_size(event
)) {
10081 * Check if the @cpu we're creating an event for is online.
10083 * We use the perf_cpu_context::ctx::mutex to serialize against
10084 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10086 struct perf_cpu_context
*cpuctx
=
10087 container_of(ctx
, struct perf_cpu_context
, ctx
);
10089 if (!cpuctx
->online
) {
10097 * Must be under the same ctx::mutex as perf_install_in_context(),
10098 * because we need to serialize with concurrent event creation.
10100 if (!exclusive_event_installable(event
, ctx
)) {
10101 /* exclusive and group stuff are assumed mutually exclusive */
10102 WARN_ON_ONCE(move_group
);
10108 WARN_ON_ONCE(ctx
->parent_ctx
);
10111 * This is the point on no return; we cannot fail hereafter. This is
10112 * where we start modifying current state.
10117 * See perf_event_ctx_lock() for comments on the details
10118 * of swizzling perf_event::ctx.
10120 perf_remove_from_context(group_leader
, 0);
10123 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
10125 perf_remove_from_context(sibling
, 0);
10130 * Wait for everybody to stop referencing the events through
10131 * the old lists, before installing it on new lists.
10136 * Install the group siblings before the group leader.
10138 * Because a group leader will try and install the entire group
10139 * (through the sibling list, which is still in-tact), we can
10140 * end up with siblings installed in the wrong context.
10142 * By installing siblings first we NO-OP because they're not
10143 * reachable through the group lists.
10145 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
10147 perf_event__state_init(sibling
);
10148 perf_install_in_context(ctx
, sibling
, sibling
->cpu
);
10153 * Removing from the context ends up with disabled
10154 * event. What we want here is event in the initial
10155 * startup state, ready to be add into new context.
10157 perf_event__state_init(group_leader
);
10158 perf_install_in_context(ctx
, group_leader
, group_leader
->cpu
);
10163 * Precalculate sample_data sizes; do while holding ctx::mutex such
10164 * that we're serialized against further additions and before
10165 * perf_install_in_context() which is the point the event is active and
10166 * can use these values.
10168 perf_event__header_size(event
);
10169 perf_event__id_header_size(event
);
10171 event
->owner
= current
;
10173 perf_install_in_context(ctx
, event
, event
->cpu
);
10174 perf_unpin_context(ctx
);
10177 perf_event_ctx_unlock(group_leader
, gctx
);
10178 mutex_unlock(&ctx
->mutex
);
10181 mutex_unlock(&task
->signal
->cred_guard_mutex
);
10182 put_task_struct(task
);
10185 mutex_lock(¤t
->perf_event_mutex
);
10186 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
10187 mutex_unlock(¤t
->perf_event_mutex
);
10190 * Drop the reference on the group_event after placing the
10191 * new event on the sibling_list. This ensures destruction
10192 * of the group leader will find the pointer to itself in
10193 * perf_group_detach().
10196 fd_install(event_fd
, event_file
);
10201 perf_event_ctx_unlock(group_leader
, gctx
);
10202 mutex_unlock(&ctx
->mutex
);
10206 perf_unpin_context(ctx
);
10210 * If event_file is set, the fput() above will have called ->release()
10211 * and that will take care of freeing the event.
10217 mutex_unlock(&task
->signal
->cred_guard_mutex
);
10220 put_task_struct(task
);
10224 put_unused_fd(event_fd
);
10229 * perf_event_create_kernel_counter
10231 * @attr: attributes of the counter to create
10232 * @cpu: cpu in which the counter is bound
10233 * @task: task to profile (NULL for percpu)
10235 struct perf_event
*
10236 perf_event_create_kernel_counter(struct perf_event_attr
*attr
, int cpu
,
10237 struct task_struct
*task
,
10238 perf_overflow_handler_t overflow_handler
,
10241 struct perf_event_context
*ctx
;
10242 struct perf_event
*event
;
10246 * Get the target context (task or percpu):
10249 event
= perf_event_alloc(attr
, cpu
, task
, NULL
, NULL
,
10250 overflow_handler
, context
, -1);
10251 if (IS_ERR(event
)) {
10252 err
= PTR_ERR(event
);
10256 /* Mark owner so we could distinguish it from user events. */
10257 event
->owner
= TASK_TOMBSTONE
;
10259 ctx
= find_get_context(event
->pmu
, task
, event
);
10261 err
= PTR_ERR(ctx
);
10265 WARN_ON_ONCE(ctx
->parent_ctx
);
10266 mutex_lock(&ctx
->mutex
);
10267 if (ctx
->task
== TASK_TOMBSTONE
) {
10274 * Check if the @cpu we're creating an event for is online.
10276 * We use the perf_cpu_context::ctx::mutex to serialize against
10277 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10279 struct perf_cpu_context
*cpuctx
=
10280 container_of(ctx
, struct perf_cpu_context
, ctx
);
10281 if (!cpuctx
->online
) {
10287 if (!exclusive_event_installable(event
, ctx
)) {
10292 perf_install_in_context(ctx
, event
, cpu
);
10293 perf_unpin_context(ctx
);
10294 mutex_unlock(&ctx
->mutex
);
10299 mutex_unlock(&ctx
->mutex
);
10300 perf_unpin_context(ctx
);
10305 return ERR_PTR(err
);
10307 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter
);
10309 void perf_pmu_migrate_context(struct pmu
*pmu
, int src_cpu
, int dst_cpu
)
10311 struct perf_event_context
*src_ctx
;
10312 struct perf_event_context
*dst_ctx
;
10313 struct perf_event
*event
, *tmp
;
10316 src_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, src_cpu
)->ctx
;
10317 dst_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, dst_cpu
)->ctx
;
10320 * See perf_event_ctx_lock() for comments on the details
10321 * of swizzling perf_event::ctx.
10323 mutex_lock_double(&src_ctx
->mutex
, &dst_ctx
->mutex
);
10324 list_for_each_entry_safe(event
, tmp
, &src_ctx
->event_list
,
10326 perf_remove_from_context(event
, 0);
10327 unaccount_event_cpu(event
, src_cpu
);
10329 list_add(&event
->migrate_entry
, &events
);
10333 * Wait for the events to quiesce before re-instating them.
10338 * Re-instate events in 2 passes.
10340 * Skip over group leaders and only install siblings on this first
10341 * pass, siblings will not get enabled without a leader, however a
10342 * leader will enable its siblings, even if those are still on the old
10345 list_for_each_entry_safe(event
, tmp
, &events
, migrate_entry
) {
10346 if (event
->group_leader
== event
)
10349 list_del(&event
->migrate_entry
);
10350 if (event
->state
>= PERF_EVENT_STATE_OFF
)
10351 event
->state
= PERF_EVENT_STATE_INACTIVE
;
10352 account_event_cpu(event
, dst_cpu
);
10353 perf_install_in_context(dst_ctx
, event
, dst_cpu
);
10358 * Once all the siblings are setup properly, install the group leaders
10361 list_for_each_entry_safe(event
, tmp
, &events
, migrate_entry
) {
10362 list_del(&event
->migrate_entry
);
10363 if (event
->state
>= PERF_EVENT_STATE_OFF
)
10364 event
->state
= PERF_EVENT_STATE_INACTIVE
;
10365 account_event_cpu(event
, dst_cpu
);
10366 perf_install_in_context(dst_ctx
, event
, dst_cpu
);
10369 mutex_unlock(&dst_ctx
->mutex
);
10370 mutex_unlock(&src_ctx
->mutex
);
10372 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context
);
10374 static void sync_child_event(struct perf_event
*child_event
,
10375 struct task_struct
*child
)
10377 struct perf_event
*parent_event
= child_event
->parent
;
10380 if (child_event
->attr
.inherit_stat
)
10381 perf_event_read_event(child_event
, child
);
10383 child_val
= perf_event_count(child_event
);
10386 * Add back the child's count to the parent's count:
10388 atomic64_add(child_val
, &parent_event
->child_count
);
10389 atomic64_add(child_event
->total_time_enabled
,
10390 &parent_event
->child_total_time_enabled
);
10391 atomic64_add(child_event
->total_time_running
,
10392 &parent_event
->child_total_time_running
);
10396 perf_event_exit_event(struct perf_event
*child_event
,
10397 struct perf_event_context
*child_ctx
,
10398 struct task_struct
*child
)
10400 struct perf_event
*parent_event
= child_event
->parent
;
10403 * Do not destroy the 'original' grouping; because of the context
10404 * switch optimization the original events could've ended up in a
10405 * random child task.
10407 * If we were to destroy the original group, all group related
10408 * operations would cease to function properly after this random
10411 * Do destroy all inherited groups, we don't care about those
10412 * and being thorough is better.
10414 raw_spin_lock_irq(&child_ctx
->lock
);
10415 WARN_ON_ONCE(child_ctx
->is_active
);
10418 perf_group_detach(child_event
);
10419 list_del_event(child_event
, child_ctx
);
10420 child_event
->state
= PERF_EVENT_STATE_EXIT
; /* is_event_hup() */
10421 raw_spin_unlock_irq(&child_ctx
->lock
);
10424 * Parent events are governed by their filedesc, retain them.
10426 if (!parent_event
) {
10427 perf_event_wakeup(child_event
);
10431 * Child events can be cleaned up.
10434 sync_child_event(child_event
, child
);
10437 * Remove this event from the parent's list
10439 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
10440 mutex_lock(&parent_event
->child_mutex
);
10441 list_del_init(&child_event
->child_list
);
10442 mutex_unlock(&parent_event
->child_mutex
);
10445 * Kick perf_poll() for is_event_hup().
10447 perf_event_wakeup(parent_event
);
10448 free_event(child_event
);
10449 put_event(parent_event
);
10452 static void perf_event_exit_task_context(struct task_struct
*child
, int ctxn
)
10454 struct perf_event_context
*child_ctx
, *clone_ctx
= NULL
;
10455 struct perf_event
*child_event
, *next
;
10457 WARN_ON_ONCE(child
!= current
);
10459 child_ctx
= perf_pin_task_context(child
, ctxn
);
10464 * In order to reduce the amount of tricky in ctx tear-down, we hold
10465 * ctx::mutex over the entire thing. This serializes against almost
10466 * everything that wants to access the ctx.
10468 * The exception is sys_perf_event_open() /
10469 * perf_event_create_kernel_count() which does find_get_context()
10470 * without ctx::mutex (it cannot because of the move_group double mutex
10471 * lock thing). See the comments in perf_install_in_context().
10473 mutex_lock(&child_ctx
->mutex
);
10476 * In a single ctx::lock section, de-schedule the events and detach the
10477 * context from the task such that we cannot ever get it scheduled back
10480 raw_spin_lock_irq(&child_ctx
->lock
);
10481 task_ctx_sched_out(__get_cpu_context(child_ctx
), child_ctx
, EVENT_ALL
);
10484 * Now that the context is inactive, destroy the task <-> ctx relation
10485 * and mark the context dead.
10487 RCU_INIT_POINTER(child
->perf_event_ctxp
[ctxn
], NULL
);
10488 put_ctx(child_ctx
); /* cannot be last */
10489 WRITE_ONCE(child_ctx
->task
, TASK_TOMBSTONE
);
10490 put_task_struct(current
); /* cannot be last */
10492 clone_ctx
= unclone_ctx(child_ctx
);
10493 raw_spin_unlock_irq(&child_ctx
->lock
);
10496 put_ctx(clone_ctx
);
10499 * Report the task dead after unscheduling the events so that we
10500 * won't get any samples after PERF_RECORD_EXIT. We can however still
10501 * get a few PERF_RECORD_READ events.
10503 perf_event_task(child
, child_ctx
, 0);
10505 list_for_each_entry_safe(child_event
, next
, &child_ctx
->event_list
, event_entry
)
10506 perf_event_exit_event(child_event
, child_ctx
, child
);
10508 mutex_unlock(&child_ctx
->mutex
);
10510 put_ctx(child_ctx
);
10514 * When a child task exits, feed back event values to parent events.
10516 * Can be called with cred_guard_mutex held when called from
10517 * install_exec_creds().
10519 void perf_event_exit_task(struct task_struct
*child
)
10521 struct perf_event
*event
, *tmp
;
10524 mutex_lock(&child
->perf_event_mutex
);
10525 list_for_each_entry_safe(event
, tmp
, &child
->perf_event_list
,
10527 list_del_init(&event
->owner_entry
);
10530 * Ensure the list deletion is visible before we clear
10531 * the owner, closes a race against perf_release() where
10532 * we need to serialize on the owner->perf_event_mutex.
10534 smp_store_release(&event
->owner
, NULL
);
10536 mutex_unlock(&child
->perf_event_mutex
);
10538 for_each_task_context_nr(ctxn
)
10539 perf_event_exit_task_context(child
, ctxn
);
10542 * The perf_event_exit_task_context calls perf_event_task
10543 * with child's task_ctx, which generates EXIT events for
10544 * child contexts and sets child->perf_event_ctxp[] to NULL.
10545 * At this point we need to send EXIT events to cpu contexts.
10547 perf_event_task(child
, NULL
, 0);
10550 static void perf_free_event(struct perf_event
*event
,
10551 struct perf_event_context
*ctx
)
10553 struct perf_event
*parent
= event
->parent
;
10555 if (WARN_ON_ONCE(!parent
))
10558 mutex_lock(&parent
->child_mutex
);
10559 list_del_init(&event
->child_list
);
10560 mutex_unlock(&parent
->child_mutex
);
10564 raw_spin_lock_irq(&ctx
->lock
);
10565 perf_group_detach(event
);
10566 list_del_event(event
, ctx
);
10567 raw_spin_unlock_irq(&ctx
->lock
);
10572 * Free an unexposed, unused context as created by inheritance by
10573 * perf_event_init_task below, used by fork() in case of fail.
10575 * Not all locks are strictly required, but take them anyway to be nice and
10576 * help out with the lockdep assertions.
10578 void perf_event_free_task(struct task_struct
*task
)
10580 struct perf_event_context
*ctx
;
10581 struct perf_event
*event
, *tmp
;
10584 for_each_task_context_nr(ctxn
) {
10585 ctx
= task
->perf_event_ctxp
[ctxn
];
10589 mutex_lock(&ctx
->mutex
);
10590 raw_spin_lock_irq(&ctx
->lock
);
10592 * Destroy the task <-> ctx relation and mark the context dead.
10594 * This is important because even though the task hasn't been
10595 * exposed yet the context has been (through child_list).
10597 RCU_INIT_POINTER(task
->perf_event_ctxp
[ctxn
], NULL
);
10598 WRITE_ONCE(ctx
->task
, TASK_TOMBSTONE
);
10599 put_task_struct(task
); /* cannot be last */
10600 raw_spin_unlock_irq(&ctx
->lock
);
10602 list_for_each_entry_safe(event
, tmp
, &ctx
->event_list
, event_entry
)
10603 perf_free_event(event
, ctx
);
10605 mutex_unlock(&ctx
->mutex
);
10610 void perf_event_delayed_put(struct task_struct
*task
)
10614 for_each_task_context_nr(ctxn
)
10615 WARN_ON_ONCE(task
->perf_event_ctxp
[ctxn
]);
10618 struct file
*perf_event_get(unsigned int fd
)
10622 file
= fget_raw(fd
);
10624 return ERR_PTR(-EBADF
);
10626 if (file
->f_op
!= &perf_fops
) {
10628 return ERR_PTR(-EBADF
);
10634 const struct perf_event_attr
*perf_event_attrs(struct perf_event
*event
)
10637 return ERR_PTR(-EINVAL
);
10639 return &event
->attr
;
10643 * Inherit a event from parent task to child task.
10646 * - valid pointer on success
10647 * - NULL for orphaned events
10648 * - IS_ERR() on error
10650 static struct perf_event
*
10651 inherit_event(struct perf_event
*parent_event
,
10652 struct task_struct
*parent
,
10653 struct perf_event_context
*parent_ctx
,
10654 struct task_struct
*child
,
10655 struct perf_event
*group_leader
,
10656 struct perf_event_context
*child_ctx
)
10658 enum perf_event_active_state parent_state
= parent_event
->state
;
10659 struct perf_event
*child_event
;
10660 unsigned long flags
;
10663 * Instead of creating recursive hierarchies of events,
10664 * we link inherited events back to the original parent,
10665 * which has a filp for sure, which we use as the reference
10668 if (parent_event
->parent
)
10669 parent_event
= parent_event
->parent
;
10671 child_event
= perf_event_alloc(&parent_event
->attr
,
10674 group_leader
, parent_event
,
10676 if (IS_ERR(child_event
))
10677 return child_event
;
10680 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10681 * must be under the same lock in order to serialize against
10682 * perf_event_release_kernel(), such that either we must observe
10683 * is_orphaned_event() or they will observe us on the child_list.
10685 mutex_lock(&parent_event
->child_mutex
);
10686 if (is_orphaned_event(parent_event
) ||
10687 !atomic_long_inc_not_zero(&parent_event
->refcount
)) {
10688 mutex_unlock(&parent_event
->child_mutex
);
10689 free_event(child_event
);
10693 get_ctx(child_ctx
);
10696 * Make the child state follow the state of the parent event,
10697 * not its attr.disabled bit. We hold the parent's mutex,
10698 * so we won't race with perf_event_{en, dis}able_family.
10700 if (parent_state
>= PERF_EVENT_STATE_INACTIVE
)
10701 child_event
->state
= PERF_EVENT_STATE_INACTIVE
;
10703 child_event
->state
= PERF_EVENT_STATE_OFF
;
10705 if (parent_event
->attr
.freq
) {
10706 u64 sample_period
= parent_event
->hw
.sample_period
;
10707 struct hw_perf_event
*hwc
= &child_event
->hw
;
10709 hwc
->sample_period
= sample_period
;
10710 hwc
->last_period
= sample_period
;
10712 local64_set(&hwc
->period_left
, sample_period
);
10715 child_event
->ctx
= child_ctx
;
10716 child_event
->overflow_handler
= parent_event
->overflow_handler
;
10717 child_event
->overflow_handler_context
10718 = parent_event
->overflow_handler_context
;
10721 * Precalculate sample_data sizes
10723 perf_event__header_size(child_event
);
10724 perf_event__id_header_size(child_event
);
10727 * Link it up in the child's context:
10729 raw_spin_lock_irqsave(&child_ctx
->lock
, flags
);
10730 add_event_to_ctx(child_event
, child_ctx
);
10731 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
10734 * Link this into the parent event's child list
10736 list_add_tail(&child_event
->child_list
, &parent_event
->child_list
);
10737 mutex_unlock(&parent_event
->child_mutex
);
10739 return child_event
;
10743 * Inherits an event group.
10745 * This will quietly suppress orphaned events; !inherit_event() is not an error.
10746 * This matches with perf_event_release_kernel() removing all child events.
10752 static int inherit_group(struct perf_event
*parent_event
,
10753 struct task_struct
*parent
,
10754 struct perf_event_context
*parent_ctx
,
10755 struct task_struct
*child
,
10756 struct perf_event_context
*child_ctx
)
10758 struct perf_event
*leader
;
10759 struct perf_event
*sub
;
10760 struct perf_event
*child_ctr
;
10762 leader
= inherit_event(parent_event
, parent
, parent_ctx
,
10763 child
, NULL
, child_ctx
);
10764 if (IS_ERR(leader
))
10765 return PTR_ERR(leader
);
10767 * @leader can be NULL here because of is_orphaned_event(). In this
10768 * case inherit_event() will create individual events, similar to what
10769 * perf_group_detach() would do anyway.
10771 list_for_each_entry(sub
, &parent_event
->sibling_list
, group_entry
) {
10772 child_ctr
= inherit_event(sub
, parent
, parent_ctx
,
10773 child
, leader
, child_ctx
);
10774 if (IS_ERR(child_ctr
))
10775 return PTR_ERR(child_ctr
);
10781 * Creates the child task context and tries to inherit the event-group.
10783 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
10784 * inherited_all set when we 'fail' to inherit an orphaned event; this is
10785 * consistent with perf_event_release_kernel() removing all child events.
10792 inherit_task_group(struct perf_event
*event
, struct task_struct
*parent
,
10793 struct perf_event_context
*parent_ctx
,
10794 struct task_struct
*child
, int ctxn
,
10795 int *inherited_all
)
10798 struct perf_event_context
*child_ctx
;
10800 if (!event
->attr
.inherit
) {
10801 *inherited_all
= 0;
10805 child_ctx
= child
->perf_event_ctxp
[ctxn
];
10808 * This is executed from the parent task context, so
10809 * inherit events that have been marked for cloning.
10810 * First allocate and initialize a context for the
10813 child_ctx
= alloc_perf_context(parent_ctx
->pmu
, child
);
10817 child
->perf_event_ctxp
[ctxn
] = child_ctx
;
10820 ret
= inherit_group(event
, parent
, parent_ctx
,
10824 *inherited_all
= 0;
10830 * Initialize the perf_event context in task_struct
10832 static int perf_event_init_context(struct task_struct
*child
, int ctxn
)
10834 struct perf_event_context
*child_ctx
, *parent_ctx
;
10835 struct perf_event_context
*cloned_ctx
;
10836 struct perf_event
*event
;
10837 struct task_struct
*parent
= current
;
10838 int inherited_all
= 1;
10839 unsigned long flags
;
10842 if (likely(!parent
->perf_event_ctxp
[ctxn
]))
10846 * If the parent's context is a clone, pin it so it won't get
10847 * swapped under us.
10849 parent_ctx
= perf_pin_task_context(parent
, ctxn
);
10854 * No need to check if parent_ctx != NULL here; since we saw
10855 * it non-NULL earlier, the only reason for it to become NULL
10856 * is if we exit, and since we're currently in the middle of
10857 * a fork we can't be exiting at the same time.
10861 * Lock the parent list. No need to lock the child - not PID
10862 * hashed yet and not running, so nobody can access it.
10864 mutex_lock(&parent_ctx
->mutex
);
10867 * We dont have to disable NMIs - we are only looking at
10868 * the list, not manipulating it:
10870 list_for_each_entry(event
, &parent_ctx
->pinned_groups
, group_entry
) {
10871 ret
= inherit_task_group(event
, parent
, parent_ctx
,
10872 child
, ctxn
, &inherited_all
);
10878 * We can't hold ctx->lock when iterating the ->flexible_group list due
10879 * to allocations, but we need to prevent rotation because
10880 * rotate_ctx() will change the list from interrupt context.
10882 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
10883 parent_ctx
->rotate_disable
= 1;
10884 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
10886 list_for_each_entry(event
, &parent_ctx
->flexible_groups
, group_entry
) {
10887 ret
= inherit_task_group(event
, parent
, parent_ctx
,
10888 child
, ctxn
, &inherited_all
);
10893 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
10894 parent_ctx
->rotate_disable
= 0;
10896 child_ctx
= child
->perf_event_ctxp
[ctxn
];
10898 if (child_ctx
&& inherited_all
) {
10900 * Mark the child context as a clone of the parent
10901 * context, or of whatever the parent is a clone of.
10903 * Note that if the parent is a clone, the holding of
10904 * parent_ctx->lock avoids it from being uncloned.
10906 cloned_ctx
= parent_ctx
->parent_ctx
;
10908 child_ctx
->parent_ctx
= cloned_ctx
;
10909 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
10911 child_ctx
->parent_ctx
= parent_ctx
;
10912 child_ctx
->parent_gen
= parent_ctx
->generation
;
10914 get_ctx(child_ctx
->parent_ctx
);
10917 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
10919 mutex_unlock(&parent_ctx
->mutex
);
10921 perf_unpin_context(parent_ctx
);
10922 put_ctx(parent_ctx
);
10928 * Initialize the perf_event context in task_struct
10930 int perf_event_init_task(struct task_struct
*child
)
10934 memset(child
->perf_event_ctxp
, 0, sizeof(child
->perf_event_ctxp
));
10935 mutex_init(&child
->perf_event_mutex
);
10936 INIT_LIST_HEAD(&child
->perf_event_list
);
10938 for_each_task_context_nr(ctxn
) {
10939 ret
= perf_event_init_context(child
, ctxn
);
10941 perf_event_free_task(child
);
10949 static void __init
perf_event_init_all_cpus(void)
10951 struct swevent_htable
*swhash
;
10954 zalloc_cpumask_var(&perf_online_mask
, GFP_KERNEL
);
10956 for_each_possible_cpu(cpu
) {
10957 swhash
= &per_cpu(swevent_htable
, cpu
);
10958 mutex_init(&swhash
->hlist_mutex
);
10959 INIT_LIST_HEAD(&per_cpu(active_ctx_list
, cpu
));
10961 INIT_LIST_HEAD(&per_cpu(pmu_sb_events
.list
, cpu
));
10962 raw_spin_lock_init(&per_cpu(pmu_sb_events
.lock
, cpu
));
10964 #ifdef CONFIG_CGROUP_PERF
10965 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list
, cpu
));
10967 INIT_LIST_HEAD(&per_cpu(sched_cb_list
, cpu
));
10971 void perf_swevent_init_cpu(unsigned int cpu
)
10973 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
10975 mutex_lock(&swhash
->hlist_mutex
);
10976 if (swhash
->hlist_refcount
> 0 && !swevent_hlist_deref(swhash
)) {
10977 struct swevent_hlist
*hlist
;
10979 hlist
= kzalloc_node(sizeof(*hlist
), GFP_KERNEL
, cpu_to_node(cpu
));
10981 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
10983 mutex_unlock(&swhash
->hlist_mutex
);
10986 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
10987 static void __perf_event_exit_context(void *__info
)
10989 struct perf_event_context
*ctx
= __info
;
10990 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
10991 struct perf_event
*event
;
10993 raw_spin_lock(&ctx
->lock
);
10994 list_for_each_entry(event
, &ctx
->event_list
, event_entry
)
10995 __perf_remove_from_context(event
, cpuctx
, ctx
, (void *)DETACH_GROUP
);
10996 raw_spin_unlock(&ctx
->lock
);
10999 static void perf_event_exit_cpu_context(int cpu
)
11001 struct perf_cpu_context
*cpuctx
;
11002 struct perf_event_context
*ctx
;
11005 mutex_lock(&pmus_lock
);
11006 list_for_each_entry(pmu
, &pmus
, entry
) {
11007 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
11008 ctx
= &cpuctx
->ctx
;
11010 mutex_lock(&ctx
->mutex
);
11011 smp_call_function_single(cpu
, __perf_event_exit_context
, ctx
, 1);
11012 cpuctx
->online
= 0;
11013 mutex_unlock(&ctx
->mutex
);
11015 cpumask_clear_cpu(cpu
, perf_online_mask
);
11016 mutex_unlock(&pmus_lock
);
11020 static void perf_event_exit_cpu_context(int cpu
) { }
11024 int perf_event_init_cpu(unsigned int cpu
)
11026 struct perf_cpu_context
*cpuctx
;
11027 struct perf_event_context
*ctx
;
11030 perf_swevent_init_cpu(cpu
);
11032 mutex_lock(&pmus_lock
);
11033 cpumask_set_cpu(cpu
, perf_online_mask
);
11034 list_for_each_entry(pmu
, &pmus
, entry
) {
11035 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
11036 ctx
= &cpuctx
->ctx
;
11038 mutex_lock(&ctx
->mutex
);
11039 cpuctx
->online
= 1;
11040 mutex_unlock(&ctx
->mutex
);
11042 mutex_unlock(&pmus_lock
);
11047 int perf_event_exit_cpu(unsigned int cpu
)
11049 perf_event_exit_cpu_context(cpu
);
11054 perf_reboot(struct notifier_block
*notifier
, unsigned long val
, void *v
)
11058 for_each_online_cpu(cpu
)
11059 perf_event_exit_cpu(cpu
);
11065 * Run the perf reboot notifier at the very last possible moment so that
11066 * the generic watchdog code runs as long as possible.
11068 static struct notifier_block perf_reboot_notifier
= {
11069 .notifier_call
= perf_reboot
,
11070 .priority
= INT_MIN
,
11073 void __init
perf_event_init(void)
11077 idr_init(&pmu_idr
);
11079 perf_event_init_all_cpus();
11080 init_srcu_struct(&pmus_srcu
);
11081 perf_pmu_register(&perf_swevent
, "software", PERF_TYPE_SOFTWARE
);
11082 perf_pmu_register(&perf_cpu_clock
, NULL
, -1);
11083 perf_pmu_register(&perf_task_clock
, NULL
, -1);
11084 perf_tp_register();
11085 perf_event_init_cpu(smp_processor_id());
11086 register_reboot_notifier(&perf_reboot_notifier
);
11088 ret
= init_hw_breakpoint();
11089 WARN(ret
, "hw_breakpoint initialization failed with: %d", ret
);
11092 * Build time assertion that we keep the data_head at the intended
11093 * location. IOW, validation we got the __reserved[] size right.
11095 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page
, data_head
))
11099 ssize_t
perf_event_sysfs_show(struct device
*dev
, struct device_attribute
*attr
,
11102 struct perf_pmu_events_attr
*pmu_attr
=
11103 container_of(attr
, struct perf_pmu_events_attr
, attr
);
11105 if (pmu_attr
->event_str
)
11106 return sprintf(page
, "%s\n", pmu_attr
->event_str
);
11110 EXPORT_SYMBOL_GPL(perf_event_sysfs_show
);
11112 static int __init
perf_event_sysfs_init(void)
11117 mutex_lock(&pmus_lock
);
11119 ret
= bus_register(&pmu_bus
);
11123 list_for_each_entry(pmu
, &pmus
, entry
) {
11124 if (!pmu
->name
|| pmu
->type
< 0)
11127 ret
= pmu_dev_alloc(pmu
);
11128 WARN(ret
, "Failed to register pmu: %s, reason %d\n", pmu
->name
, ret
);
11130 pmu_bus_running
= 1;
11134 mutex_unlock(&pmus_lock
);
11138 device_initcall(perf_event_sysfs_init
);
11140 #ifdef CONFIG_CGROUP_PERF
11141 static struct cgroup_subsys_state
*
11142 perf_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
11144 struct perf_cgroup
*jc
;
11146 jc
= kzalloc(sizeof(*jc
), GFP_KERNEL
);
11148 return ERR_PTR(-ENOMEM
);
11150 jc
->info
= alloc_percpu(struct perf_cgroup_info
);
11153 return ERR_PTR(-ENOMEM
);
11159 static void perf_cgroup_css_free(struct cgroup_subsys_state
*css
)
11161 struct perf_cgroup
*jc
= container_of(css
, struct perf_cgroup
, css
);
11163 free_percpu(jc
->info
);
11167 static int __perf_cgroup_move(void *info
)
11169 struct task_struct
*task
= info
;
11171 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
| PERF_CGROUP_SWIN
);
11176 static void perf_cgroup_attach(struct cgroup_taskset
*tset
)
11178 struct task_struct
*task
;
11179 struct cgroup_subsys_state
*css
;
11181 cgroup_taskset_for_each(task
, css
, tset
)
11182 task_function_call(task
, __perf_cgroup_move
, task
);
11185 struct cgroup_subsys perf_event_cgrp_subsys
= {
11186 .css_alloc
= perf_cgroup_css_alloc
,
11187 .css_free
= perf_cgroup_css_free
,
11188 .attach
= perf_cgroup_attach
,
11190 * Implicitly enable on dfl hierarchy so that perf events can
11191 * always be filtered by cgroup2 path as long as perf_event
11192 * controller is not mounted on a legacy hierarchy.
11194 .implicit_on_dfl
= true,
11196 #endif /* CONFIG_CGROUP_PERF */