2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/idr.h>
17 #include <linux/file.h>
18 #include <linux/poll.h>
19 #include <linux/slab.h>
20 #include <linux/hash.h>
21 #include <linux/tick.h>
22 #include <linux/sysfs.h>
23 #include <linux/dcache.h>
24 #include <linux/percpu.h>
25 #include <linux/ptrace.h>
26 #include <linux/reboot.h>
27 #include <linux/vmstat.h>
28 #include <linux/device.h>
29 #include <linux/export.h>
30 #include <linux/vmalloc.h>
31 #include <linux/hardirq.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/cgroup.h>
38 #include <linux/perf_event.h>
39 #include <linux/trace_events.h>
40 #include <linux/hw_breakpoint.h>
41 #include <linux/mm_types.h>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
45 #include <linux/bpf.h>
46 #include <linux/filter.h>
47 #include <linux/namei.h>
48 #include <linux/parser.h>
49 #include <linux/sched/clock.h>
50 #include <linux/sched/mm.h>
51 #include <linux/proc_ns.h>
52 #include <linux/mount.h>
56 #include <asm/irq_regs.h>
58 typedef int (*remote_function_f
)(void *);
60 struct remote_function_call
{
61 struct task_struct
*p
;
62 remote_function_f func
;
67 static void remote_function(void *data
)
69 struct remote_function_call
*tfc
= data
;
70 struct task_struct
*p
= tfc
->p
;
74 if (task_cpu(p
) != smp_processor_id())
78 * Now that we're on right CPU with IRQs disabled, we can test
79 * if we hit the right task without races.
82 tfc
->ret
= -ESRCH
; /* No such (running) process */
87 tfc
->ret
= tfc
->func(tfc
->info
);
91 * task_function_call - call a function on the cpu on which a task runs
92 * @p: the task to evaluate
93 * @func: the function to be called
94 * @info: the function call argument
96 * Calls the function @func when the task is currently running. This might
97 * be on the current CPU, which just calls the function directly
99 * returns: @func return value, or
100 * -ESRCH - when the process isn't running
101 * -EAGAIN - when the process moved away
104 task_function_call(struct task_struct
*p
, remote_function_f func
, void *info
)
106 struct remote_function_call data
= {
115 ret
= smp_call_function_single(task_cpu(p
), remote_function
, &data
, 1);
118 } while (ret
== -EAGAIN
);
124 * cpu_function_call - call a function on the cpu
125 * @func: the function to be called
126 * @info: the function call argument
128 * Calls the function @func on the remote cpu.
130 * returns: @func return value or -ENXIO when the cpu is offline
132 static int cpu_function_call(int cpu
, remote_function_f func
, void *info
)
134 struct remote_function_call data
= {
138 .ret
= -ENXIO
, /* No such CPU */
141 smp_call_function_single(cpu
, remote_function
, &data
, 1);
146 static inline struct perf_cpu_context
*
147 __get_cpu_context(struct perf_event_context
*ctx
)
149 return this_cpu_ptr(ctx
->pmu
->pmu_cpu_context
);
152 static void perf_ctx_lock(struct perf_cpu_context
*cpuctx
,
153 struct perf_event_context
*ctx
)
155 raw_spin_lock(&cpuctx
->ctx
.lock
);
157 raw_spin_lock(&ctx
->lock
);
160 static void perf_ctx_unlock(struct perf_cpu_context
*cpuctx
,
161 struct perf_event_context
*ctx
)
164 raw_spin_unlock(&ctx
->lock
);
165 raw_spin_unlock(&cpuctx
->ctx
.lock
);
168 #define TASK_TOMBSTONE ((void *)-1L)
170 static bool is_kernel_event(struct perf_event
*event
)
172 return READ_ONCE(event
->owner
) == TASK_TOMBSTONE
;
176 * On task ctx scheduling...
178 * When !ctx->nr_events a task context will not be scheduled. This means
179 * we can disable the scheduler hooks (for performance) without leaving
180 * pending task ctx state.
182 * This however results in two special cases:
184 * - removing the last event from a task ctx; this is relatively straight
185 * forward and is done in __perf_remove_from_context.
187 * - adding the first event to a task ctx; this is tricky because we cannot
188 * rely on ctx->is_active and therefore cannot use event_function_call().
189 * See perf_install_in_context().
191 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
194 typedef void (*event_f
)(struct perf_event
*, struct perf_cpu_context
*,
195 struct perf_event_context
*, void *);
197 struct event_function_struct
{
198 struct perf_event
*event
;
203 static int event_function(void *info
)
205 struct event_function_struct
*efs
= info
;
206 struct perf_event
*event
= efs
->event
;
207 struct perf_event_context
*ctx
= event
->ctx
;
208 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
209 struct perf_event_context
*task_ctx
= cpuctx
->task_ctx
;
212 WARN_ON_ONCE(!irqs_disabled());
214 perf_ctx_lock(cpuctx
, task_ctx
);
216 * Since we do the IPI call without holding ctx->lock things can have
217 * changed, double check we hit the task we set out to hit.
220 if (ctx
->task
!= current
) {
226 * We only use event_function_call() on established contexts,
227 * and event_function() is only ever called when active (or
228 * rather, we'll have bailed in task_function_call() or the
229 * above ctx->task != current test), therefore we must have
230 * ctx->is_active here.
232 WARN_ON_ONCE(!ctx
->is_active
);
234 * And since we have ctx->is_active, cpuctx->task_ctx must
237 WARN_ON_ONCE(task_ctx
!= ctx
);
239 WARN_ON_ONCE(&cpuctx
->ctx
!= ctx
);
242 efs
->func(event
, cpuctx
, ctx
, efs
->data
);
244 perf_ctx_unlock(cpuctx
, task_ctx
);
249 static void event_function_call(struct perf_event
*event
, event_f func
, void *data
)
251 struct perf_event_context
*ctx
= event
->ctx
;
252 struct task_struct
*task
= READ_ONCE(ctx
->task
); /* verified in event_function */
253 struct event_function_struct efs
= {
259 if (!event
->parent
) {
261 * If this is a !child event, we must hold ctx::mutex to
262 * stabilize the the event->ctx relation. See
263 * perf_event_ctx_lock().
265 lockdep_assert_held(&ctx
->mutex
);
269 cpu_function_call(event
->cpu
, event_function
, &efs
);
273 if (task
== TASK_TOMBSTONE
)
277 if (!task_function_call(task
, event_function
, &efs
))
280 raw_spin_lock_irq(&ctx
->lock
);
282 * Reload the task pointer, it might have been changed by
283 * a concurrent perf_event_context_sched_out().
286 if (task
== TASK_TOMBSTONE
) {
287 raw_spin_unlock_irq(&ctx
->lock
);
290 if (ctx
->is_active
) {
291 raw_spin_unlock_irq(&ctx
->lock
);
294 func(event
, NULL
, ctx
, data
);
295 raw_spin_unlock_irq(&ctx
->lock
);
299 * Similar to event_function_call() + event_function(), but hard assumes IRQs
300 * are already disabled and we're on the right CPU.
302 static void event_function_local(struct perf_event
*event
, event_f func
, void *data
)
304 struct perf_event_context
*ctx
= event
->ctx
;
305 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
306 struct task_struct
*task
= READ_ONCE(ctx
->task
);
307 struct perf_event_context
*task_ctx
= NULL
;
309 WARN_ON_ONCE(!irqs_disabled());
312 if (task
== TASK_TOMBSTONE
)
318 perf_ctx_lock(cpuctx
, task_ctx
);
321 if (task
== TASK_TOMBSTONE
)
326 * We must be either inactive or active and the right task,
327 * otherwise we're screwed, since we cannot IPI to somewhere
330 if (ctx
->is_active
) {
331 if (WARN_ON_ONCE(task
!= current
))
334 if (WARN_ON_ONCE(cpuctx
->task_ctx
!= ctx
))
338 WARN_ON_ONCE(&cpuctx
->ctx
!= ctx
);
341 func(event
, cpuctx
, ctx
, data
);
343 perf_ctx_unlock(cpuctx
, task_ctx
);
346 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
347 PERF_FLAG_FD_OUTPUT |\
348 PERF_FLAG_PID_CGROUP |\
349 PERF_FLAG_FD_CLOEXEC)
352 * branch priv levels that need permission checks
354 #define PERF_SAMPLE_BRANCH_PERM_PLM \
355 (PERF_SAMPLE_BRANCH_KERNEL |\
356 PERF_SAMPLE_BRANCH_HV)
359 EVENT_FLEXIBLE
= 0x1,
362 /* see ctx_resched() for details */
364 EVENT_ALL
= EVENT_FLEXIBLE
| EVENT_PINNED
,
368 * perf_sched_events : >0 events exist
369 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
372 static void perf_sched_delayed(struct work_struct
*work
);
373 DEFINE_STATIC_KEY_FALSE(perf_sched_events
);
374 static DECLARE_DELAYED_WORK(perf_sched_work
, perf_sched_delayed
);
375 static DEFINE_MUTEX(perf_sched_mutex
);
376 static atomic_t perf_sched_count
;
378 static DEFINE_PER_CPU(atomic_t
, perf_cgroup_events
);
379 static DEFINE_PER_CPU(int, perf_sched_cb_usages
);
380 static DEFINE_PER_CPU(struct pmu_event_list
, pmu_sb_events
);
382 static atomic_t nr_mmap_events __read_mostly
;
383 static atomic_t nr_comm_events __read_mostly
;
384 static atomic_t nr_namespaces_events __read_mostly
;
385 static atomic_t nr_task_events __read_mostly
;
386 static atomic_t nr_freq_events __read_mostly
;
387 static atomic_t nr_switch_events __read_mostly
;
389 static LIST_HEAD(pmus
);
390 static DEFINE_MUTEX(pmus_lock
);
391 static struct srcu_struct pmus_srcu
;
392 static cpumask_var_t perf_online_mask
;
395 * perf event paranoia level:
396 * -1 - not paranoid at all
397 * 0 - disallow raw tracepoint access for unpriv
398 * 1 - disallow cpu events for unpriv
399 * 2 - disallow kernel profiling for unpriv
401 int sysctl_perf_event_paranoid __read_mostly
= 2;
403 /* Minimum for 512 kiB + 1 user control page */
404 int sysctl_perf_event_mlock __read_mostly
= 512 + (PAGE_SIZE
/ 1024); /* 'free' kiB per user */
407 * max perf event sample rate
409 #define DEFAULT_MAX_SAMPLE_RATE 100000
410 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
411 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
413 int sysctl_perf_event_sample_rate __read_mostly
= DEFAULT_MAX_SAMPLE_RATE
;
415 static int max_samples_per_tick __read_mostly
= DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE
, HZ
);
416 static int perf_sample_period_ns __read_mostly
= DEFAULT_SAMPLE_PERIOD_NS
;
418 static int perf_sample_allowed_ns __read_mostly
=
419 DEFAULT_SAMPLE_PERIOD_NS
* DEFAULT_CPU_TIME_MAX_PERCENT
/ 100;
421 static void update_perf_cpu_limits(void)
423 u64 tmp
= perf_sample_period_ns
;
425 tmp
*= sysctl_perf_cpu_time_max_percent
;
426 tmp
= div_u64(tmp
, 100);
430 WRITE_ONCE(perf_sample_allowed_ns
, tmp
);
433 static int perf_rotate_context(struct perf_cpu_context
*cpuctx
);
435 int perf_proc_update_handler(struct ctl_table
*table
, int write
,
436 void __user
*buffer
, size_t *lenp
,
439 int ret
= proc_dointvec_minmax(table
, write
, buffer
, lenp
, ppos
);
445 * If throttling is disabled don't allow the write:
447 if (sysctl_perf_cpu_time_max_percent
== 100 ||
448 sysctl_perf_cpu_time_max_percent
== 0)
451 max_samples_per_tick
= DIV_ROUND_UP(sysctl_perf_event_sample_rate
, HZ
);
452 perf_sample_period_ns
= NSEC_PER_SEC
/ sysctl_perf_event_sample_rate
;
453 update_perf_cpu_limits();
458 int sysctl_perf_cpu_time_max_percent __read_mostly
= DEFAULT_CPU_TIME_MAX_PERCENT
;
460 int perf_cpu_time_max_percent_handler(struct ctl_table
*table
, int write
,
461 void __user
*buffer
, size_t *lenp
,
464 int ret
= proc_dointvec_minmax(table
, write
, buffer
, lenp
, ppos
);
469 if (sysctl_perf_cpu_time_max_percent
== 100 ||
470 sysctl_perf_cpu_time_max_percent
== 0) {
472 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
473 WRITE_ONCE(perf_sample_allowed_ns
, 0);
475 update_perf_cpu_limits();
482 * perf samples are done in some very critical code paths (NMIs).
483 * If they take too much CPU time, the system can lock up and not
484 * get any real work done. This will drop the sample rate when
485 * we detect that events are taking too long.
487 #define NR_ACCUMULATED_SAMPLES 128
488 static DEFINE_PER_CPU(u64
, running_sample_length
);
490 static u64 __report_avg
;
491 static u64 __report_allowed
;
493 static void perf_duration_warn(struct irq_work
*w
)
495 printk_ratelimited(KERN_INFO
496 "perf: interrupt took too long (%lld > %lld), lowering "
497 "kernel.perf_event_max_sample_rate to %d\n",
498 __report_avg
, __report_allowed
,
499 sysctl_perf_event_sample_rate
);
502 static DEFINE_IRQ_WORK(perf_duration_work
, perf_duration_warn
);
504 void perf_sample_event_took(u64 sample_len_ns
)
506 u64 max_len
= READ_ONCE(perf_sample_allowed_ns
);
514 /* Decay the counter by 1 average sample. */
515 running_len
= __this_cpu_read(running_sample_length
);
516 running_len
-= running_len
/NR_ACCUMULATED_SAMPLES
;
517 running_len
+= sample_len_ns
;
518 __this_cpu_write(running_sample_length
, running_len
);
521 * Note: this will be biased artifically low until we have
522 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
523 * from having to maintain a count.
525 avg_len
= running_len
/NR_ACCUMULATED_SAMPLES
;
526 if (avg_len
<= max_len
)
529 __report_avg
= avg_len
;
530 __report_allowed
= max_len
;
533 * Compute a throttle threshold 25% below the current duration.
535 avg_len
+= avg_len
/ 4;
536 max
= (TICK_NSEC
/ 100) * sysctl_perf_cpu_time_max_percent
;
542 WRITE_ONCE(perf_sample_allowed_ns
, avg_len
);
543 WRITE_ONCE(max_samples_per_tick
, max
);
545 sysctl_perf_event_sample_rate
= max
* HZ
;
546 perf_sample_period_ns
= NSEC_PER_SEC
/ sysctl_perf_event_sample_rate
;
548 if (!irq_work_queue(&perf_duration_work
)) {
549 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
550 "kernel.perf_event_max_sample_rate to %d\n",
551 __report_avg
, __report_allowed
,
552 sysctl_perf_event_sample_rate
);
556 static atomic64_t perf_event_id
;
558 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
559 enum event_type_t event_type
);
561 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
562 enum event_type_t event_type
,
563 struct task_struct
*task
);
565 static void update_context_time(struct perf_event_context
*ctx
);
566 static u64
perf_event_time(struct perf_event
*event
);
568 void __weak
perf_event_print_debug(void) { }
570 extern __weak
const char *perf_pmu_name(void)
575 static inline u64
perf_clock(void)
577 return local_clock();
580 static inline u64
perf_event_clock(struct perf_event
*event
)
582 return event
->clock();
585 #ifdef CONFIG_CGROUP_PERF
588 perf_cgroup_match(struct perf_event
*event
)
590 struct perf_event_context
*ctx
= event
->ctx
;
591 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
593 /* @event doesn't care about cgroup */
597 /* wants specific cgroup scope but @cpuctx isn't associated with any */
602 * Cgroup scoping is recursive. An event enabled for a cgroup is
603 * also enabled for all its descendant cgroups. If @cpuctx's
604 * cgroup is a descendant of @event's (the test covers identity
605 * case), it's a match.
607 return cgroup_is_descendant(cpuctx
->cgrp
->css
.cgroup
,
608 event
->cgrp
->css
.cgroup
);
611 static inline void perf_detach_cgroup(struct perf_event
*event
)
613 css_put(&event
->cgrp
->css
);
617 static inline int is_cgroup_event(struct perf_event
*event
)
619 return event
->cgrp
!= NULL
;
622 static inline u64
perf_cgroup_event_time(struct perf_event
*event
)
624 struct perf_cgroup_info
*t
;
626 t
= per_cpu_ptr(event
->cgrp
->info
, event
->cpu
);
630 static inline void __update_cgrp_time(struct perf_cgroup
*cgrp
)
632 struct perf_cgroup_info
*info
;
637 info
= this_cpu_ptr(cgrp
->info
);
639 info
->time
+= now
- info
->timestamp
;
640 info
->timestamp
= now
;
643 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context
*cpuctx
)
645 struct perf_cgroup
*cgrp_out
= cpuctx
->cgrp
;
647 __update_cgrp_time(cgrp_out
);
650 static inline void update_cgrp_time_from_event(struct perf_event
*event
)
652 struct perf_cgroup
*cgrp
;
655 * ensure we access cgroup data only when needed and
656 * when we know the cgroup is pinned (css_get)
658 if (!is_cgroup_event(event
))
661 cgrp
= perf_cgroup_from_task(current
, event
->ctx
);
663 * Do not update time when cgroup is not active
665 if (cgroup_is_descendant(cgrp
->css
.cgroup
, event
->cgrp
->css
.cgroup
))
666 __update_cgrp_time(event
->cgrp
);
670 perf_cgroup_set_timestamp(struct task_struct
*task
,
671 struct perf_event_context
*ctx
)
673 struct perf_cgroup
*cgrp
;
674 struct perf_cgroup_info
*info
;
677 * ctx->lock held by caller
678 * ensure we do not access cgroup data
679 * unless we have the cgroup pinned (css_get)
681 if (!task
|| !ctx
->nr_cgroups
)
684 cgrp
= perf_cgroup_from_task(task
, ctx
);
685 info
= this_cpu_ptr(cgrp
->info
);
686 info
->timestamp
= ctx
->timestamp
;
689 static DEFINE_PER_CPU(struct list_head
, cgrp_cpuctx_list
);
691 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
692 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
695 * reschedule events based on the cgroup constraint of task.
697 * mode SWOUT : schedule out everything
698 * mode SWIN : schedule in based on cgroup for next
700 static void perf_cgroup_switch(struct task_struct
*task
, int mode
)
702 struct perf_cpu_context
*cpuctx
;
703 struct list_head
*list
;
707 * Disable interrupts and preemption to avoid this CPU's
708 * cgrp_cpuctx_entry to change under us.
710 local_irq_save(flags
);
712 list
= this_cpu_ptr(&cgrp_cpuctx_list
);
713 list_for_each_entry(cpuctx
, list
, cgrp_cpuctx_entry
) {
714 WARN_ON_ONCE(cpuctx
->ctx
.nr_cgroups
== 0);
716 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
717 perf_pmu_disable(cpuctx
->ctx
.pmu
);
719 if (mode
& PERF_CGROUP_SWOUT
) {
720 cpu_ctx_sched_out(cpuctx
, EVENT_ALL
);
722 * must not be done before ctxswout due
723 * to event_filter_match() in event_sched_out()
728 if (mode
& PERF_CGROUP_SWIN
) {
729 WARN_ON_ONCE(cpuctx
->cgrp
);
731 * set cgrp before ctxsw in to allow
732 * event_filter_match() to not have to pass
734 * we pass the cpuctx->ctx to perf_cgroup_from_task()
735 * because cgorup events are only per-cpu
737 cpuctx
->cgrp
= perf_cgroup_from_task(task
,
739 cpu_ctx_sched_in(cpuctx
, EVENT_ALL
, task
);
741 perf_pmu_enable(cpuctx
->ctx
.pmu
);
742 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
745 local_irq_restore(flags
);
748 static inline void perf_cgroup_sched_out(struct task_struct
*task
,
749 struct task_struct
*next
)
751 struct perf_cgroup
*cgrp1
;
752 struct perf_cgroup
*cgrp2
= NULL
;
756 * we come here when we know perf_cgroup_events > 0
757 * we do not need to pass the ctx here because we know
758 * we are holding the rcu lock
760 cgrp1
= perf_cgroup_from_task(task
, NULL
);
761 cgrp2
= perf_cgroup_from_task(next
, NULL
);
764 * only schedule out current cgroup events if we know
765 * that we are switching to a different cgroup. Otherwise,
766 * do no touch the cgroup events.
769 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
);
774 static inline void perf_cgroup_sched_in(struct task_struct
*prev
,
775 struct task_struct
*task
)
777 struct perf_cgroup
*cgrp1
;
778 struct perf_cgroup
*cgrp2
= NULL
;
782 * we come here when we know perf_cgroup_events > 0
783 * we do not need to pass the ctx here because we know
784 * we are holding the rcu lock
786 cgrp1
= perf_cgroup_from_task(task
, NULL
);
787 cgrp2
= perf_cgroup_from_task(prev
, NULL
);
790 * only need to schedule in cgroup events if we are changing
791 * cgroup during ctxsw. Cgroup events were not scheduled
792 * out of ctxsw out if that was not the case.
795 perf_cgroup_switch(task
, PERF_CGROUP_SWIN
);
800 static inline int perf_cgroup_connect(int fd
, struct perf_event
*event
,
801 struct perf_event_attr
*attr
,
802 struct perf_event
*group_leader
)
804 struct perf_cgroup
*cgrp
;
805 struct cgroup_subsys_state
*css
;
806 struct fd f
= fdget(fd
);
812 css
= css_tryget_online_from_dir(f
.file
->f_path
.dentry
,
813 &perf_event_cgrp_subsys
);
819 cgrp
= container_of(css
, struct perf_cgroup
, css
);
823 * all events in a group must monitor
824 * the same cgroup because a task belongs
825 * to only one perf cgroup at a time
827 if (group_leader
&& group_leader
->cgrp
!= cgrp
) {
828 perf_detach_cgroup(event
);
837 perf_cgroup_set_shadow_time(struct perf_event
*event
, u64 now
)
839 struct perf_cgroup_info
*t
;
840 t
= per_cpu_ptr(event
->cgrp
->info
, event
->cpu
);
841 event
->shadow_ctx_time
= now
- t
->timestamp
;
845 perf_cgroup_defer_enabled(struct perf_event
*event
)
848 * when the current task's perf cgroup does not match
849 * the event's, we need to remember to call the
850 * perf_mark_enable() function the first time a task with
851 * a matching perf cgroup is scheduled in.
853 if (is_cgroup_event(event
) && !perf_cgroup_match(event
))
854 event
->cgrp_defer_enabled
= 1;
858 perf_cgroup_mark_enabled(struct perf_event
*event
,
859 struct perf_event_context
*ctx
)
861 struct perf_event
*sub
;
862 u64 tstamp
= perf_event_time(event
);
864 if (!event
->cgrp_defer_enabled
)
867 event
->cgrp_defer_enabled
= 0;
869 event
->tstamp_enabled
= tstamp
- event
->total_time_enabled
;
870 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
871 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
) {
872 sub
->tstamp_enabled
= tstamp
- sub
->total_time_enabled
;
873 sub
->cgrp_defer_enabled
= 0;
879 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
880 * cleared when last cgroup event is removed.
883 list_update_cgroup_event(struct perf_event
*event
,
884 struct perf_event_context
*ctx
, bool add
)
886 struct perf_cpu_context
*cpuctx
;
887 struct list_head
*cpuctx_entry
;
889 if (!is_cgroup_event(event
))
892 if (add
&& ctx
->nr_cgroups
++)
894 else if (!add
&& --ctx
->nr_cgroups
)
897 * Because cgroup events are always per-cpu events,
898 * this will always be called from the right CPU.
900 cpuctx
= __get_cpu_context(ctx
);
901 cpuctx_entry
= &cpuctx
->cgrp_cpuctx_entry
;
902 /* cpuctx->cgrp is NULL unless a cgroup event is active in this CPU .*/
904 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_type(struct perf_event
*event
, struct task_struct
*p
,
1257 * only top level events have the pid namespace they were created in
1260 event
= event
->parent
;
1262 nr
= __task_pid_nr_ns(p
, type
, event
->ns
);
1263 /* avoid -1 if it is idle thread or runs in another ns */
1264 if (!nr
&& !pid_alive(p
))
1269 static u32
perf_event_pid(struct perf_event
*event
, struct task_struct
*p
)
1271 return perf_event_pid_type(event
, p
, __PIDTYPE_TGID
);
1274 static u32
perf_event_tid(struct perf_event
*event
, struct task_struct
*p
)
1276 return perf_event_pid_type(event
, p
, PIDTYPE_PID
);
1280 * If we inherit events we want to return the parent event id
1283 static u64
primary_event_id(struct perf_event
*event
)
1288 id
= event
->parent
->id
;
1294 * Get the perf_event_context for a task and lock it.
1296 * This has to cope with with the fact that until it is locked,
1297 * the context could get moved to another task.
1299 static struct perf_event_context
*
1300 perf_lock_task_context(struct task_struct
*task
, int ctxn
, unsigned long *flags
)
1302 struct perf_event_context
*ctx
;
1306 * One of the few rules of preemptible RCU is that one cannot do
1307 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1308 * part of the read side critical section was irqs-enabled -- see
1309 * rcu_read_unlock_special().
1311 * Since ctx->lock nests under rq->lock we must ensure the entire read
1312 * side critical section has interrupts disabled.
1314 local_irq_save(*flags
);
1316 ctx
= rcu_dereference(task
->perf_event_ctxp
[ctxn
]);
1319 * If this context is a clone of another, it might
1320 * get swapped for another underneath us by
1321 * perf_event_task_sched_out, though the
1322 * rcu_read_lock() protects us from any context
1323 * getting freed. Lock the context and check if it
1324 * got swapped before we could get the lock, and retry
1325 * if so. If we locked the right context, then it
1326 * can't get swapped on us any more.
1328 raw_spin_lock(&ctx
->lock
);
1329 if (ctx
!= rcu_dereference(task
->perf_event_ctxp
[ctxn
])) {
1330 raw_spin_unlock(&ctx
->lock
);
1332 local_irq_restore(*flags
);
1336 if (ctx
->task
== TASK_TOMBSTONE
||
1337 !atomic_inc_not_zero(&ctx
->refcount
)) {
1338 raw_spin_unlock(&ctx
->lock
);
1341 WARN_ON_ONCE(ctx
->task
!= task
);
1346 local_irq_restore(*flags
);
1351 * Get the context for a task and increment its pin_count so it
1352 * can't get swapped to another task. This also increments its
1353 * reference count so that the context can't get freed.
1355 static struct perf_event_context
*
1356 perf_pin_task_context(struct task_struct
*task
, int ctxn
)
1358 struct perf_event_context
*ctx
;
1359 unsigned long flags
;
1361 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
1364 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1369 static void perf_unpin_context(struct perf_event_context
*ctx
)
1371 unsigned long flags
;
1373 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
1375 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
1379 * Update the record of the current time in a context.
1381 static void update_context_time(struct perf_event_context
*ctx
)
1383 u64 now
= perf_clock();
1385 ctx
->time
+= now
- ctx
->timestamp
;
1386 ctx
->timestamp
= now
;
1389 static u64
perf_event_time(struct perf_event
*event
)
1391 struct perf_event_context
*ctx
= event
->ctx
;
1393 if (is_cgroup_event(event
))
1394 return perf_cgroup_event_time(event
);
1396 return ctx
? ctx
->time
: 0;
1400 * Update the total_time_enabled and total_time_running fields for a event.
1402 static void update_event_times(struct perf_event
*event
)
1404 struct perf_event_context
*ctx
= event
->ctx
;
1407 lockdep_assert_held(&ctx
->lock
);
1409 if (event
->state
< PERF_EVENT_STATE_INACTIVE
||
1410 event
->group_leader
->state
< PERF_EVENT_STATE_INACTIVE
)
1414 * in cgroup mode, time_enabled represents
1415 * the time the event was enabled AND active
1416 * tasks were in the monitored cgroup. This is
1417 * independent of the activity of the context as
1418 * there may be a mix of cgroup and non-cgroup events.
1420 * That is why we treat cgroup events differently
1423 if (is_cgroup_event(event
))
1424 run_end
= perf_cgroup_event_time(event
);
1425 else if (ctx
->is_active
)
1426 run_end
= ctx
->time
;
1428 run_end
= event
->tstamp_stopped
;
1430 event
->total_time_enabled
= run_end
- event
->tstamp_enabled
;
1432 if (event
->state
== PERF_EVENT_STATE_INACTIVE
)
1433 run_end
= event
->tstamp_stopped
;
1435 run_end
= perf_event_time(event
);
1437 event
->total_time_running
= run_end
- event
->tstamp_running
;
1442 * Update total_time_enabled and total_time_running for all events in a group.
1444 static void update_group_times(struct perf_event
*leader
)
1446 struct perf_event
*event
;
1448 update_event_times(leader
);
1449 list_for_each_entry(event
, &leader
->sibling_list
, group_entry
)
1450 update_event_times(event
);
1453 static enum event_type_t
get_event_type(struct perf_event
*event
)
1455 struct perf_event_context
*ctx
= event
->ctx
;
1456 enum event_type_t event_type
;
1458 lockdep_assert_held(&ctx
->lock
);
1461 * It's 'group type', really, because if our group leader is
1462 * pinned, so are we.
1464 if (event
->group_leader
!= event
)
1465 event
= event
->group_leader
;
1467 event_type
= event
->attr
.pinned
? EVENT_PINNED
: EVENT_FLEXIBLE
;
1469 event_type
|= EVENT_CPU
;
1474 static struct list_head
*
1475 ctx_group_list(struct perf_event
*event
, struct perf_event_context
*ctx
)
1477 if (event
->attr
.pinned
)
1478 return &ctx
->pinned_groups
;
1480 return &ctx
->flexible_groups
;
1484 * Add a event from the lists for its context.
1485 * Must be called with ctx->mutex and ctx->lock held.
1488 list_add_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
1490 lockdep_assert_held(&ctx
->lock
);
1492 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_CONTEXT
);
1493 event
->attach_state
|= PERF_ATTACH_CONTEXT
;
1496 * If we're a stand alone event or group leader, we go to the context
1497 * list, group events are kept attached to the group so that
1498 * perf_group_detach can, at all times, locate all siblings.
1500 if (event
->group_leader
== event
) {
1501 struct list_head
*list
;
1503 event
->group_caps
= event
->event_caps
;
1505 list
= ctx_group_list(event
, ctx
);
1506 list_add_tail(&event
->group_entry
, list
);
1509 list_update_cgroup_event(event
, ctx
, true);
1511 list_add_rcu(&event
->event_entry
, &ctx
->event_list
);
1513 if (event
->attr
.inherit_stat
)
1520 * Initialize event state based on the perf_event_attr::disabled.
1522 static inline void perf_event__state_init(struct perf_event
*event
)
1524 event
->state
= event
->attr
.disabled
? PERF_EVENT_STATE_OFF
:
1525 PERF_EVENT_STATE_INACTIVE
;
1528 static void __perf_event_read_size(struct perf_event
*event
, int nr_siblings
)
1530 int entry
= sizeof(u64
); /* value */
1534 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
1535 size
+= sizeof(u64
);
1537 if (event
->attr
.read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
1538 size
+= sizeof(u64
);
1540 if (event
->attr
.read_format
& PERF_FORMAT_ID
)
1541 entry
+= sizeof(u64
);
1543 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
) {
1545 size
+= sizeof(u64
);
1549 event
->read_size
= size
;
1552 static void __perf_event_header_size(struct perf_event
*event
, u64 sample_type
)
1554 struct perf_sample_data
*data
;
1557 if (sample_type
& PERF_SAMPLE_IP
)
1558 size
+= sizeof(data
->ip
);
1560 if (sample_type
& PERF_SAMPLE_ADDR
)
1561 size
+= sizeof(data
->addr
);
1563 if (sample_type
& PERF_SAMPLE_PERIOD
)
1564 size
+= sizeof(data
->period
);
1566 if (sample_type
& PERF_SAMPLE_WEIGHT
)
1567 size
+= sizeof(data
->weight
);
1569 if (sample_type
& PERF_SAMPLE_READ
)
1570 size
+= event
->read_size
;
1572 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
1573 size
+= sizeof(data
->data_src
.val
);
1575 if (sample_type
& PERF_SAMPLE_TRANSACTION
)
1576 size
+= sizeof(data
->txn
);
1578 if (sample_type
& PERF_SAMPLE_PHYS_ADDR
)
1579 size
+= sizeof(data
->phys_addr
);
1581 event
->header_size
= size
;
1585 * Called at perf_event creation and when events are attached/detached from a
1588 static void perf_event__header_size(struct perf_event
*event
)
1590 __perf_event_read_size(event
,
1591 event
->group_leader
->nr_siblings
);
1592 __perf_event_header_size(event
, event
->attr
.sample_type
);
1595 static void perf_event__id_header_size(struct perf_event
*event
)
1597 struct perf_sample_data
*data
;
1598 u64 sample_type
= event
->attr
.sample_type
;
1601 if (sample_type
& PERF_SAMPLE_TID
)
1602 size
+= sizeof(data
->tid_entry
);
1604 if (sample_type
& PERF_SAMPLE_TIME
)
1605 size
+= sizeof(data
->time
);
1607 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
1608 size
+= sizeof(data
->id
);
1610 if (sample_type
& PERF_SAMPLE_ID
)
1611 size
+= sizeof(data
->id
);
1613 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
1614 size
+= sizeof(data
->stream_id
);
1616 if (sample_type
& PERF_SAMPLE_CPU
)
1617 size
+= sizeof(data
->cpu_entry
);
1619 event
->id_header_size
= size
;
1622 static bool perf_event_validate_size(struct perf_event
*event
)
1625 * The values computed here will be over-written when we actually
1628 __perf_event_read_size(event
, event
->group_leader
->nr_siblings
+ 1);
1629 __perf_event_header_size(event
, event
->attr
.sample_type
& ~PERF_SAMPLE_READ
);
1630 perf_event__id_header_size(event
);
1633 * Sum the lot; should not exceed the 64k limit we have on records.
1634 * Conservative limit to allow for callchains and other variable fields.
1636 if (event
->read_size
+ event
->header_size
+
1637 event
->id_header_size
+ sizeof(struct perf_event_header
) >= 16*1024)
1643 static void perf_group_attach(struct perf_event
*event
)
1645 struct perf_event
*group_leader
= event
->group_leader
, *pos
;
1647 lockdep_assert_held(&event
->ctx
->lock
);
1650 * We can have double attach due to group movement in perf_event_open.
1652 if (event
->attach_state
& PERF_ATTACH_GROUP
)
1655 event
->attach_state
|= PERF_ATTACH_GROUP
;
1657 if (group_leader
== event
)
1660 WARN_ON_ONCE(group_leader
->ctx
!= event
->ctx
);
1662 group_leader
->group_caps
&= event
->event_caps
;
1664 list_add_tail(&event
->group_entry
, &group_leader
->sibling_list
);
1665 group_leader
->nr_siblings
++;
1667 perf_event__header_size(group_leader
);
1669 list_for_each_entry(pos
, &group_leader
->sibling_list
, group_entry
)
1670 perf_event__header_size(pos
);
1674 * Remove a event from the lists for its context.
1675 * Must be called with ctx->mutex and ctx->lock held.
1678 list_del_event(struct perf_event
*event
, struct perf_event_context
*ctx
)
1680 WARN_ON_ONCE(event
->ctx
!= ctx
);
1681 lockdep_assert_held(&ctx
->lock
);
1684 * We can have double detach due to exit/hot-unplug + close.
1686 if (!(event
->attach_state
& PERF_ATTACH_CONTEXT
))
1689 event
->attach_state
&= ~PERF_ATTACH_CONTEXT
;
1691 list_update_cgroup_event(event
, ctx
, false);
1694 if (event
->attr
.inherit_stat
)
1697 list_del_rcu(&event
->event_entry
);
1699 if (event
->group_leader
== event
)
1700 list_del_init(&event
->group_entry
);
1702 update_group_times(event
);
1705 * If event was in error state, then keep it
1706 * that way, otherwise bogus counts will be
1707 * returned on read(). The only way to get out
1708 * of error state is by explicit re-enabling
1711 if (event
->state
> PERF_EVENT_STATE_OFF
)
1712 event
->state
= PERF_EVENT_STATE_OFF
;
1717 static void perf_group_detach(struct perf_event
*event
)
1719 struct perf_event
*sibling
, *tmp
;
1720 struct list_head
*list
= NULL
;
1722 lockdep_assert_held(&event
->ctx
->lock
);
1725 * We can have double detach due to exit/hot-unplug + close.
1727 if (!(event
->attach_state
& PERF_ATTACH_GROUP
))
1730 event
->attach_state
&= ~PERF_ATTACH_GROUP
;
1733 * If this is a sibling, remove it from its group.
1735 if (event
->group_leader
!= event
) {
1736 list_del_init(&event
->group_entry
);
1737 event
->group_leader
->nr_siblings
--;
1741 if (!list_empty(&event
->group_entry
))
1742 list
= &event
->group_entry
;
1745 * If this was a group event with sibling events then
1746 * upgrade the siblings to singleton events by adding them
1747 * to whatever list we are on.
1749 list_for_each_entry_safe(sibling
, tmp
, &event
->sibling_list
, group_entry
) {
1751 list_move_tail(&sibling
->group_entry
, list
);
1752 sibling
->group_leader
= sibling
;
1754 /* Inherit group flags from the previous leader */
1755 sibling
->group_caps
= event
->group_caps
;
1757 WARN_ON_ONCE(sibling
->ctx
!= event
->ctx
);
1761 perf_event__header_size(event
->group_leader
);
1763 list_for_each_entry(tmp
, &event
->group_leader
->sibling_list
, group_entry
)
1764 perf_event__header_size(tmp
);
1767 static bool is_orphaned_event(struct perf_event
*event
)
1769 return event
->state
== PERF_EVENT_STATE_DEAD
;
1772 static inline int __pmu_filter_match(struct perf_event
*event
)
1774 struct pmu
*pmu
= event
->pmu
;
1775 return pmu
->filter_match
? pmu
->filter_match(event
) : 1;
1779 * Check whether we should attempt to schedule an event group based on
1780 * PMU-specific filtering. An event group can consist of HW and SW events,
1781 * potentially with a SW leader, so we must check all the filters, to
1782 * determine whether a group is schedulable:
1784 static inline int pmu_filter_match(struct perf_event
*event
)
1786 struct perf_event
*child
;
1788 if (!__pmu_filter_match(event
))
1791 list_for_each_entry(child
, &event
->sibling_list
, group_entry
) {
1792 if (!__pmu_filter_match(child
))
1800 event_filter_match(struct perf_event
*event
)
1802 return (event
->cpu
== -1 || event
->cpu
== smp_processor_id()) &&
1803 perf_cgroup_match(event
) && pmu_filter_match(event
);
1807 event_sched_out(struct perf_event
*event
,
1808 struct perf_cpu_context
*cpuctx
,
1809 struct perf_event_context
*ctx
)
1811 u64 tstamp
= perf_event_time(event
);
1814 WARN_ON_ONCE(event
->ctx
!= ctx
);
1815 lockdep_assert_held(&ctx
->lock
);
1818 * An event which could not be activated because of
1819 * filter mismatch still needs to have its timings
1820 * maintained, otherwise bogus information is return
1821 * via read() for time_enabled, time_running:
1823 if (event
->state
== PERF_EVENT_STATE_INACTIVE
&&
1824 !event_filter_match(event
)) {
1825 delta
= tstamp
- event
->tstamp_stopped
;
1826 event
->tstamp_running
+= delta
;
1827 event
->tstamp_stopped
= tstamp
;
1830 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
1833 perf_pmu_disable(event
->pmu
);
1835 event
->tstamp_stopped
= tstamp
;
1836 event
->pmu
->del(event
, 0);
1838 event
->state
= PERF_EVENT_STATE_INACTIVE
;
1839 if (event
->pending_disable
) {
1840 event
->pending_disable
= 0;
1841 event
->state
= PERF_EVENT_STATE_OFF
;
1844 if (!is_software_event(event
))
1845 cpuctx
->active_oncpu
--;
1846 if (!--ctx
->nr_active
)
1847 perf_event_ctx_deactivate(ctx
);
1848 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
1850 if (event
->attr
.exclusive
|| !cpuctx
->active_oncpu
)
1851 cpuctx
->exclusive
= 0;
1853 perf_pmu_enable(event
->pmu
);
1857 group_sched_out(struct perf_event
*group_event
,
1858 struct perf_cpu_context
*cpuctx
,
1859 struct perf_event_context
*ctx
)
1861 struct perf_event
*event
;
1862 int state
= group_event
->state
;
1864 perf_pmu_disable(ctx
->pmu
);
1866 event_sched_out(group_event
, cpuctx
, ctx
);
1869 * Schedule out siblings (if any):
1871 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
)
1872 event_sched_out(event
, cpuctx
, ctx
);
1874 perf_pmu_enable(ctx
->pmu
);
1876 if (state
== PERF_EVENT_STATE_ACTIVE
&& group_event
->attr
.exclusive
)
1877 cpuctx
->exclusive
= 0;
1880 #define DETACH_GROUP 0x01UL
1883 * Cross CPU call to remove a performance event
1885 * We disable the event on the hardware level first. After that we
1886 * remove it from the context list.
1889 __perf_remove_from_context(struct perf_event
*event
,
1890 struct perf_cpu_context
*cpuctx
,
1891 struct perf_event_context
*ctx
,
1894 unsigned long flags
= (unsigned long)info
;
1896 event_sched_out(event
, cpuctx
, ctx
);
1897 if (flags
& DETACH_GROUP
)
1898 perf_group_detach(event
);
1899 list_del_event(event
, ctx
);
1901 if (!ctx
->nr_events
&& ctx
->is_active
) {
1904 WARN_ON_ONCE(cpuctx
->task_ctx
!= ctx
);
1905 cpuctx
->task_ctx
= NULL
;
1911 * Remove the event from a task's (or a CPU's) list of events.
1913 * If event->ctx is a cloned context, callers must make sure that
1914 * every task struct that event->ctx->task could possibly point to
1915 * remains valid. This is OK when called from perf_release since
1916 * that only calls us on the top-level context, which can't be a clone.
1917 * When called from perf_event_exit_task, it's OK because the
1918 * context has been detached from its task.
1920 static void perf_remove_from_context(struct perf_event
*event
, unsigned long flags
)
1922 struct perf_event_context
*ctx
= event
->ctx
;
1924 lockdep_assert_held(&ctx
->mutex
);
1926 event_function_call(event
, __perf_remove_from_context
, (void *)flags
);
1929 * The above event_function_call() can NO-OP when it hits
1930 * TASK_TOMBSTONE. In that case we must already have been detached
1931 * from the context (by perf_event_exit_event()) but the grouping
1932 * might still be in-tact.
1934 WARN_ON_ONCE(event
->attach_state
& PERF_ATTACH_CONTEXT
);
1935 if ((flags
& DETACH_GROUP
) &&
1936 (event
->attach_state
& PERF_ATTACH_GROUP
)) {
1938 * Since in that case we cannot possibly be scheduled, simply
1941 raw_spin_lock_irq(&ctx
->lock
);
1942 perf_group_detach(event
);
1943 raw_spin_unlock_irq(&ctx
->lock
);
1948 * Cross CPU call to disable a performance event
1950 static void __perf_event_disable(struct perf_event
*event
,
1951 struct perf_cpu_context
*cpuctx
,
1952 struct perf_event_context
*ctx
,
1955 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
1958 update_context_time(ctx
);
1959 update_cgrp_time_from_event(event
);
1960 update_group_times(event
);
1961 if (event
== event
->group_leader
)
1962 group_sched_out(event
, cpuctx
, ctx
);
1964 event_sched_out(event
, cpuctx
, ctx
);
1965 event
->state
= PERF_EVENT_STATE_OFF
;
1971 * If event->ctx is a cloned context, callers must make sure that
1972 * every task struct that event->ctx->task could possibly point to
1973 * remains valid. This condition is satisifed when called through
1974 * perf_event_for_each_child or perf_event_for_each because they
1975 * hold the top-level event's child_mutex, so any descendant that
1976 * goes to exit will block in perf_event_exit_event().
1978 * When called from perf_pending_event it's OK because event->ctx
1979 * is the current context on this CPU and preemption is disabled,
1980 * hence we can't get into perf_event_task_sched_out for this context.
1982 static void _perf_event_disable(struct perf_event
*event
)
1984 struct perf_event_context
*ctx
= event
->ctx
;
1986 raw_spin_lock_irq(&ctx
->lock
);
1987 if (event
->state
<= PERF_EVENT_STATE_OFF
) {
1988 raw_spin_unlock_irq(&ctx
->lock
);
1991 raw_spin_unlock_irq(&ctx
->lock
);
1993 event_function_call(event
, __perf_event_disable
, NULL
);
1996 void perf_event_disable_local(struct perf_event
*event
)
1998 event_function_local(event
, __perf_event_disable
, NULL
);
2002 * Strictly speaking kernel users cannot create groups and therefore this
2003 * interface does not need the perf_event_ctx_lock() magic.
2005 void perf_event_disable(struct perf_event
*event
)
2007 struct perf_event_context
*ctx
;
2009 ctx
= perf_event_ctx_lock(event
);
2010 _perf_event_disable(event
);
2011 perf_event_ctx_unlock(event
, ctx
);
2013 EXPORT_SYMBOL_GPL(perf_event_disable
);
2015 void perf_event_disable_inatomic(struct perf_event
*event
)
2017 event
->pending_disable
= 1;
2018 irq_work_queue(&event
->pending
);
2021 static void perf_set_shadow_time(struct perf_event
*event
,
2022 struct perf_event_context
*ctx
,
2026 * use the correct time source for the time snapshot
2028 * We could get by without this by leveraging the
2029 * fact that to get to this function, the caller
2030 * has most likely already called update_context_time()
2031 * and update_cgrp_time_xx() and thus both timestamp
2032 * are identical (or very close). Given that tstamp is,
2033 * already adjusted for cgroup, we could say that:
2034 * tstamp - ctx->timestamp
2036 * tstamp - cgrp->timestamp.
2038 * Then, in perf_output_read(), the calculation would
2039 * work with no changes because:
2040 * - event is guaranteed scheduled in
2041 * - no scheduled out in between
2042 * - thus the timestamp would be the same
2044 * But this is a bit hairy.
2046 * So instead, we have an explicit cgroup call to remain
2047 * within the time time source all along. We believe it
2048 * is cleaner and simpler to understand.
2050 if (is_cgroup_event(event
))
2051 perf_cgroup_set_shadow_time(event
, tstamp
);
2053 event
->shadow_ctx_time
= tstamp
- ctx
->timestamp
;
2056 #define MAX_INTERRUPTS (~0ULL)
2058 static void perf_log_throttle(struct perf_event
*event
, int enable
);
2059 static void perf_log_itrace_start(struct perf_event
*event
);
2062 event_sched_in(struct perf_event
*event
,
2063 struct perf_cpu_context
*cpuctx
,
2064 struct perf_event_context
*ctx
)
2066 u64 tstamp
= perf_event_time(event
);
2069 lockdep_assert_held(&ctx
->lock
);
2071 if (event
->state
<= PERF_EVENT_STATE_OFF
)
2074 WRITE_ONCE(event
->oncpu
, smp_processor_id());
2076 * Order event::oncpu write to happen before the ACTIVE state
2080 WRITE_ONCE(event
->state
, PERF_EVENT_STATE_ACTIVE
);
2083 * Unthrottle events, since we scheduled we might have missed several
2084 * ticks already, also for a heavily scheduling task there is little
2085 * guarantee it'll get a tick in a timely manner.
2087 if (unlikely(event
->hw
.interrupts
== MAX_INTERRUPTS
)) {
2088 perf_log_throttle(event
, 1);
2089 event
->hw
.interrupts
= 0;
2093 * The new state must be visible before we turn it on in the hardware:
2097 perf_pmu_disable(event
->pmu
);
2099 perf_set_shadow_time(event
, ctx
, tstamp
);
2101 perf_log_itrace_start(event
);
2103 if (event
->pmu
->add(event
, PERF_EF_START
)) {
2104 event
->state
= PERF_EVENT_STATE_INACTIVE
;
2110 event
->tstamp_running
+= tstamp
- event
->tstamp_stopped
;
2112 if (!is_software_event(event
))
2113 cpuctx
->active_oncpu
++;
2114 if (!ctx
->nr_active
++)
2115 perf_event_ctx_activate(ctx
);
2116 if (event
->attr
.freq
&& event
->attr
.sample_freq
)
2119 if (event
->attr
.exclusive
)
2120 cpuctx
->exclusive
= 1;
2123 perf_pmu_enable(event
->pmu
);
2129 group_sched_in(struct perf_event
*group_event
,
2130 struct perf_cpu_context
*cpuctx
,
2131 struct perf_event_context
*ctx
)
2133 struct perf_event
*event
, *partial_group
= NULL
;
2134 struct pmu
*pmu
= ctx
->pmu
;
2135 u64 now
= ctx
->time
;
2136 bool simulate
= false;
2138 if (group_event
->state
== PERF_EVENT_STATE_OFF
)
2141 pmu
->start_txn(pmu
, PERF_PMU_TXN_ADD
);
2143 if (event_sched_in(group_event
, cpuctx
, ctx
)) {
2144 pmu
->cancel_txn(pmu
);
2145 perf_mux_hrtimer_restart(cpuctx
);
2150 * Schedule in siblings as one group (if any):
2152 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
2153 if (event_sched_in(event
, cpuctx
, ctx
)) {
2154 partial_group
= event
;
2159 if (!pmu
->commit_txn(pmu
))
2164 * Groups can be scheduled in as one unit only, so undo any
2165 * partial group before returning:
2166 * The events up to the failed event are scheduled out normally,
2167 * tstamp_stopped will be updated.
2169 * The failed events and the remaining siblings need to have
2170 * their timings updated as if they had gone thru event_sched_in()
2171 * and event_sched_out(). This is required to get consistent timings
2172 * across the group. This also takes care of the case where the group
2173 * could never be scheduled by ensuring tstamp_stopped is set to mark
2174 * the time the event was actually stopped, such that time delta
2175 * calculation in update_event_times() is correct.
2177 list_for_each_entry(event
, &group_event
->sibling_list
, group_entry
) {
2178 if (event
== partial_group
)
2182 event
->tstamp_running
+= now
- event
->tstamp_stopped
;
2183 event
->tstamp_stopped
= now
;
2185 event_sched_out(event
, cpuctx
, ctx
);
2188 event_sched_out(group_event
, cpuctx
, ctx
);
2190 pmu
->cancel_txn(pmu
);
2192 perf_mux_hrtimer_restart(cpuctx
);
2198 * Work out whether we can put this event group on the CPU now.
2200 static int group_can_go_on(struct perf_event
*event
,
2201 struct perf_cpu_context
*cpuctx
,
2205 * Groups consisting entirely of software events can always go on.
2207 if (event
->group_caps
& PERF_EV_CAP_SOFTWARE
)
2210 * If an exclusive group is already on, no other hardware
2213 if (cpuctx
->exclusive
)
2216 * If this group is exclusive and there are already
2217 * events on the CPU, it can't go on.
2219 if (event
->attr
.exclusive
&& cpuctx
->active_oncpu
)
2222 * Otherwise, try to add it if all previous groups were able
2229 * Complement to update_event_times(). This computes the tstamp_* values to
2230 * continue 'enabled' state from @now, and effectively discards the time
2231 * between the prior tstamp_stopped and now (as we were in the OFF state, or
2232 * just switched (context) time base).
2234 * This further assumes '@event->state == INACTIVE' (we just came from OFF) and
2235 * cannot have been scheduled in yet. And going into INACTIVE state means
2236 * '@event->tstamp_stopped = @now'.
2238 * Thus given the rules of update_event_times():
2240 * total_time_enabled = tstamp_stopped - tstamp_enabled
2241 * total_time_running = tstamp_stopped - tstamp_running
2243 * We can insert 'tstamp_stopped == now' and reverse them to compute new
2246 static void __perf_event_enable_time(struct perf_event
*event
, u64 now
)
2248 WARN_ON_ONCE(event
->state
!= PERF_EVENT_STATE_INACTIVE
);
2250 event
->tstamp_stopped
= now
;
2251 event
->tstamp_enabled
= now
- event
->total_time_enabled
;
2252 event
->tstamp_running
= now
- event
->total_time_running
;
2255 static void add_event_to_ctx(struct perf_event
*event
,
2256 struct perf_event_context
*ctx
)
2258 u64 tstamp
= perf_event_time(event
);
2260 list_add_event(event
, ctx
);
2261 perf_group_attach(event
);
2263 * We can be called with event->state == STATE_OFF when we create with
2264 * .disabled = 1. In that case the IOC_ENABLE will call this function.
2266 if (event
->state
== PERF_EVENT_STATE_INACTIVE
)
2267 __perf_event_enable_time(event
, tstamp
);
2270 static void ctx_sched_out(struct perf_event_context
*ctx
,
2271 struct perf_cpu_context
*cpuctx
,
2272 enum event_type_t event_type
);
2274 ctx_sched_in(struct perf_event_context
*ctx
,
2275 struct perf_cpu_context
*cpuctx
,
2276 enum event_type_t event_type
,
2277 struct task_struct
*task
);
2279 static void task_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
2280 struct perf_event_context
*ctx
,
2281 enum event_type_t event_type
)
2283 if (!cpuctx
->task_ctx
)
2286 if (WARN_ON_ONCE(ctx
!= cpuctx
->task_ctx
))
2289 ctx_sched_out(ctx
, cpuctx
, event_type
);
2292 static void perf_event_sched_in(struct perf_cpu_context
*cpuctx
,
2293 struct perf_event_context
*ctx
,
2294 struct task_struct
*task
)
2296 cpu_ctx_sched_in(cpuctx
, EVENT_PINNED
, task
);
2298 ctx_sched_in(ctx
, cpuctx
, EVENT_PINNED
, task
);
2299 cpu_ctx_sched_in(cpuctx
, EVENT_FLEXIBLE
, task
);
2301 ctx_sched_in(ctx
, cpuctx
, EVENT_FLEXIBLE
, task
);
2305 * We want to maintain the following priority of scheduling:
2306 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2307 * - task pinned (EVENT_PINNED)
2308 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2309 * - task flexible (EVENT_FLEXIBLE).
2311 * In order to avoid unscheduling and scheduling back in everything every
2312 * time an event is added, only do it for the groups of equal priority and
2315 * This can be called after a batch operation on task events, in which case
2316 * event_type is a bit mask of the types of events involved. For CPU events,
2317 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2319 static void ctx_resched(struct perf_cpu_context
*cpuctx
,
2320 struct perf_event_context
*task_ctx
,
2321 enum event_type_t event_type
)
2323 enum event_type_t ctx_event_type
= event_type
& EVENT_ALL
;
2324 bool cpu_event
= !!(event_type
& EVENT_CPU
);
2327 * If pinned groups are involved, flexible groups also need to be
2330 if (event_type
& EVENT_PINNED
)
2331 event_type
|= EVENT_FLEXIBLE
;
2333 perf_pmu_disable(cpuctx
->ctx
.pmu
);
2335 task_ctx_sched_out(cpuctx
, task_ctx
, event_type
);
2338 * Decide which cpu ctx groups to schedule out based on the types
2339 * of events that caused rescheduling:
2340 * - EVENT_CPU: schedule out corresponding groups;
2341 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2342 * - otherwise, do nothing more.
2345 cpu_ctx_sched_out(cpuctx
, ctx_event_type
);
2346 else if (ctx_event_type
& EVENT_PINNED
)
2347 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
2349 perf_event_sched_in(cpuctx
, task_ctx
, current
);
2350 perf_pmu_enable(cpuctx
->ctx
.pmu
);
2354 * Cross CPU call to install and enable a performance event
2356 * Very similar to remote_function() + event_function() but cannot assume that
2357 * things like ctx->is_active and cpuctx->task_ctx are set.
2359 static int __perf_install_in_context(void *info
)
2361 struct perf_event
*event
= info
;
2362 struct perf_event_context
*ctx
= event
->ctx
;
2363 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
2364 struct perf_event_context
*task_ctx
= cpuctx
->task_ctx
;
2365 bool reprogram
= true;
2368 raw_spin_lock(&cpuctx
->ctx
.lock
);
2370 raw_spin_lock(&ctx
->lock
);
2373 reprogram
= (ctx
->task
== current
);
2376 * If the task is running, it must be running on this CPU,
2377 * otherwise we cannot reprogram things.
2379 * If its not running, we don't care, ctx->lock will
2380 * serialize against it becoming runnable.
2382 if (task_curr(ctx
->task
) && !reprogram
) {
2387 WARN_ON_ONCE(reprogram
&& cpuctx
->task_ctx
&& cpuctx
->task_ctx
!= ctx
);
2388 } else if (task_ctx
) {
2389 raw_spin_lock(&task_ctx
->lock
);
2393 ctx_sched_out(ctx
, cpuctx
, EVENT_TIME
);
2394 add_event_to_ctx(event
, ctx
);
2395 ctx_resched(cpuctx
, task_ctx
, get_event_type(event
));
2397 add_event_to_ctx(event
, ctx
);
2401 perf_ctx_unlock(cpuctx
, task_ctx
);
2407 * Attach a performance event to a context.
2409 * Very similar to event_function_call, see comment there.
2412 perf_install_in_context(struct perf_event_context
*ctx
,
2413 struct perf_event
*event
,
2416 struct task_struct
*task
= READ_ONCE(ctx
->task
);
2418 lockdep_assert_held(&ctx
->mutex
);
2420 if (event
->cpu
!= -1)
2424 * Ensures that if we can observe event->ctx, both the event and ctx
2425 * will be 'complete'. See perf_iterate_sb_cpu().
2427 smp_store_release(&event
->ctx
, ctx
);
2430 cpu_function_call(cpu
, __perf_install_in_context
, event
);
2435 * Should not happen, we validate the ctx is still alive before calling.
2437 if (WARN_ON_ONCE(task
== TASK_TOMBSTONE
))
2441 * Installing events is tricky because we cannot rely on ctx->is_active
2442 * to be set in case this is the nr_events 0 -> 1 transition.
2444 * Instead we use task_curr(), which tells us if the task is running.
2445 * However, since we use task_curr() outside of rq::lock, we can race
2446 * against the actual state. This means the result can be wrong.
2448 * If we get a false positive, we retry, this is harmless.
2450 * If we get a false negative, things are complicated. If we are after
2451 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2452 * value must be correct. If we're before, it doesn't matter since
2453 * perf_event_context_sched_in() will program the counter.
2455 * However, this hinges on the remote context switch having observed
2456 * our task->perf_event_ctxp[] store, such that it will in fact take
2457 * ctx::lock in perf_event_context_sched_in().
2459 * We do this by task_function_call(), if the IPI fails to hit the task
2460 * we know any future context switch of task must see the
2461 * perf_event_ctpx[] store.
2465 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2466 * task_cpu() load, such that if the IPI then does not find the task
2467 * running, a future context switch of that task must observe the
2472 if (!task_function_call(task
, __perf_install_in_context
, event
))
2475 raw_spin_lock_irq(&ctx
->lock
);
2477 if (WARN_ON_ONCE(task
== TASK_TOMBSTONE
)) {
2479 * Cannot happen because we already checked above (which also
2480 * cannot happen), and we hold ctx->mutex, which serializes us
2481 * against perf_event_exit_task_context().
2483 raw_spin_unlock_irq(&ctx
->lock
);
2487 * If the task is not running, ctx->lock will avoid it becoming so,
2488 * thus we can safely install the event.
2490 if (task_curr(task
)) {
2491 raw_spin_unlock_irq(&ctx
->lock
);
2494 add_event_to_ctx(event
, ctx
);
2495 raw_spin_unlock_irq(&ctx
->lock
);
2499 * Put a event into inactive state and update time fields.
2500 * Enabling the leader of a group effectively enables all
2501 * the group members that aren't explicitly disabled, so we
2502 * have to update their ->tstamp_enabled also.
2503 * Note: this works for group members as well as group leaders
2504 * since the non-leader members' sibling_lists will be empty.
2506 static void __perf_event_mark_enabled(struct perf_event
*event
)
2508 struct perf_event
*sub
;
2509 u64 tstamp
= perf_event_time(event
);
2511 event
->state
= PERF_EVENT_STATE_INACTIVE
;
2512 __perf_event_enable_time(event
, tstamp
);
2513 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
2514 /* XXX should not be > INACTIVE if event isn't */
2515 if (sub
->state
>= PERF_EVENT_STATE_INACTIVE
)
2516 __perf_event_enable_time(sub
, tstamp
);
2521 * Cross CPU call to enable a performance event
2523 static void __perf_event_enable(struct perf_event
*event
,
2524 struct perf_cpu_context
*cpuctx
,
2525 struct perf_event_context
*ctx
,
2528 struct perf_event
*leader
= event
->group_leader
;
2529 struct perf_event_context
*task_ctx
;
2531 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
||
2532 event
->state
<= PERF_EVENT_STATE_ERROR
)
2536 ctx_sched_out(ctx
, cpuctx
, EVENT_TIME
);
2538 __perf_event_mark_enabled(event
);
2540 if (!ctx
->is_active
)
2543 if (!event_filter_match(event
)) {
2544 if (is_cgroup_event(event
))
2545 perf_cgroup_defer_enabled(event
);
2546 ctx_sched_in(ctx
, cpuctx
, EVENT_TIME
, current
);
2551 * If the event is in a group and isn't the group leader,
2552 * then don't put it on unless the group is on.
2554 if (leader
!= event
&& leader
->state
!= PERF_EVENT_STATE_ACTIVE
) {
2555 ctx_sched_in(ctx
, cpuctx
, EVENT_TIME
, current
);
2559 task_ctx
= cpuctx
->task_ctx
;
2561 WARN_ON_ONCE(task_ctx
!= ctx
);
2563 ctx_resched(cpuctx
, task_ctx
, get_event_type(event
));
2569 * If event->ctx is a cloned context, callers must make sure that
2570 * every task struct that event->ctx->task could possibly point to
2571 * remains valid. This condition is satisfied when called through
2572 * perf_event_for_each_child or perf_event_for_each as described
2573 * for perf_event_disable.
2575 static void _perf_event_enable(struct perf_event
*event
)
2577 struct perf_event_context
*ctx
= event
->ctx
;
2579 raw_spin_lock_irq(&ctx
->lock
);
2580 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
||
2581 event
->state
< PERF_EVENT_STATE_ERROR
) {
2582 raw_spin_unlock_irq(&ctx
->lock
);
2587 * If the event is in error state, clear that first.
2589 * That way, if we see the event in error state below, we know that it
2590 * has gone back into error state, as distinct from the task having
2591 * been scheduled away before the cross-call arrived.
2593 if (event
->state
== PERF_EVENT_STATE_ERROR
)
2594 event
->state
= PERF_EVENT_STATE_OFF
;
2595 raw_spin_unlock_irq(&ctx
->lock
);
2597 event_function_call(event
, __perf_event_enable
, NULL
);
2601 * See perf_event_disable();
2603 void perf_event_enable(struct perf_event
*event
)
2605 struct perf_event_context
*ctx
;
2607 ctx
= perf_event_ctx_lock(event
);
2608 _perf_event_enable(event
);
2609 perf_event_ctx_unlock(event
, ctx
);
2611 EXPORT_SYMBOL_GPL(perf_event_enable
);
2613 struct stop_event_data
{
2614 struct perf_event
*event
;
2615 unsigned int restart
;
2618 static int __perf_event_stop(void *info
)
2620 struct stop_event_data
*sd
= info
;
2621 struct perf_event
*event
= sd
->event
;
2623 /* if it's already INACTIVE, do nothing */
2624 if (READ_ONCE(event
->state
) != PERF_EVENT_STATE_ACTIVE
)
2627 /* matches smp_wmb() in event_sched_in() */
2631 * There is a window with interrupts enabled before we get here,
2632 * so we need to check again lest we try to stop another CPU's event.
2634 if (READ_ONCE(event
->oncpu
) != smp_processor_id())
2637 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
2640 * May race with the actual stop (through perf_pmu_output_stop()),
2641 * but it is only used for events with AUX ring buffer, and such
2642 * events will refuse to restart because of rb::aux_mmap_count==0,
2643 * see comments in perf_aux_output_begin().
2645 * Since this is happening on a event-local CPU, no trace is lost
2649 event
->pmu
->start(event
, 0);
2654 static int perf_event_stop(struct perf_event
*event
, int restart
)
2656 struct stop_event_data sd
= {
2663 if (READ_ONCE(event
->state
) != PERF_EVENT_STATE_ACTIVE
)
2666 /* matches smp_wmb() in event_sched_in() */
2670 * We only want to restart ACTIVE events, so if the event goes
2671 * inactive here (event->oncpu==-1), there's nothing more to do;
2672 * fall through with ret==-ENXIO.
2674 ret
= cpu_function_call(READ_ONCE(event
->oncpu
),
2675 __perf_event_stop
, &sd
);
2676 } while (ret
== -EAGAIN
);
2682 * In order to contain the amount of racy and tricky in the address filter
2683 * configuration management, it is a two part process:
2685 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2686 * we update the addresses of corresponding vmas in
2687 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2688 * (p2) when an event is scheduled in (pmu::add), it calls
2689 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2690 * if the generation has changed since the previous call.
2692 * If (p1) happens while the event is active, we restart it to force (p2).
2694 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2695 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2697 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2698 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2700 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2703 void perf_event_addr_filters_sync(struct perf_event
*event
)
2705 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
2707 if (!has_addr_filter(event
))
2710 raw_spin_lock(&ifh
->lock
);
2711 if (event
->addr_filters_gen
!= event
->hw
.addr_filters_gen
) {
2712 event
->pmu
->addr_filters_sync(event
);
2713 event
->hw
.addr_filters_gen
= event
->addr_filters_gen
;
2715 raw_spin_unlock(&ifh
->lock
);
2717 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync
);
2719 static int _perf_event_refresh(struct perf_event
*event
, int refresh
)
2722 * not supported on inherited events
2724 if (event
->attr
.inherit
|| !is_sampling_event(event
))
2727 atomic_add(refresh
, &event
->event_limit
);
2728 _perf_event_enable(event
);
2734 * See perf_event_disable()
2736 int perf_event_refresh(struct perf_event
*event
, int refresh
)
2738 struct perf_event_context
*ctx
;
2741 ctx
= perf_event_ctx_lock(event
);
2742 ret
= _perf_event_refresh(event
, refresh
);
2743 perf_event_ctx_unlock(event
, ctx
);
2747 EXPORT_SYMBOL_GPL(perf_event_refresh
);
2749 static void ctx_sched_out(struct perf_event_context
*ctx
,
2750 struct perf_cpu_context
*cpuctx
,
2751 enum event_type_t event_type
)
2753 int is_active
= ctx
->is_active
;
2754 struct perf_event
*event
;
2756 lockdep_assert_held(&ctx
->lock
);
2758 if (likely(!ctx
->nr_events
)) {
2760 * See __perf_remove_from_context().
2762 WARN_ON_ONCE(ctx
->is_active
);
2764 WARN_ON_ONCE(cpuctx
->task_ctx
);
2768 ctx
->is_active
&= ~event_type
;
2769 if (!(ctx
->is_active
& EVENT_ALL
))
2773 WARN_ON_ONCE(cpuctx
->task_ctx
!= ctx
);
2774 if (!ctx
->is_active
)
2775 cpuctx
->task_ctx
= NULL
;
2779 * Always update time if it was set; not only when it changes.
2780 * Otherwise we can 'forget' to update time for any but the last
2781 * context we sched out. For example:
2783 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2784 * ctx_sched_out(.event_type = EVENT_PINNED)
2786 * would only update time for the pinned events.
2788 if (is_active
& EVENT_TIME
) {
2789 /* update (and stop) ctx time */
2790 update_context_time(ctx
);
2791 update_cgrp_time_from_cpuctx(cpuctx
);
2794 is_active
^= ctx
->is_active
; /* changed bits */
2796 if (!ctx
->nr_active
|| !(is_active
& EVENT_ALL
))
2799 perf_pmu_disable(ctx
->pmu
);
2800 if (is_active
& EVENT_PINNED
) {
2801 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
)
2802 group_sched_out(event
, cpuctx
, ctx
);
2805 if (is_active
& EVENT_FLEXIBLE
) {
2806 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
)
2807 group_sched_out(event
, cpuctx
, ctx
);
2809 perf_pmu_enable(ctx
->pmu
);
2813 * Test whether two contexts are equivalent, i.e. whether they have both been
2814 * cloned from the same version of the same context.
2816 * Equivalence is measured using a generation number in the context that is
2817 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2818 * and list_del_event().
2820 static int context_equiv(struct perf_event_context
*ctx1
,
2821 struct perf_event_context
*ctx2
)
2823 lockdep_assert_held(&ctx1
->lock
);
2824 lockdep_assert_held(&ctx2
->lock
);
2826 /* Pinning disables the swap optimization */
2827 if (ctx1
->pin_count
|| ctx2
->pin_count
)
2830 /* If ctx1 is the parent of ctx2 */
2831 if (ctx1
== ctx2
->parent_ctx
&& ctx1
->generation
== ctx2
->parent_gen
)
2834 /* If ctx2 is the parent of ctx1 */
2835 if (ctx1
->parent_ctx
== ctx2
&& ctx1
->parent_gen
== ctx2
->generation
)
2839 * If ctx1 and ctx2 have the same parent; we flatten the parent
2840 * hierarchy, see perf_event_init_context().
2842 if (ctx1
->parent_ctx
&& ctx1
->parent_ctx
== ctx2
->parent_ctx
&&
2843 ctx1
->parent_gen
== ctx2
->parent_gen
)
2850 static void __perf_event_sync_stat(struct perf_event
*event
,
2851 struct perf_event
*next_event
)
2855 if (!event
->attr
.inherit_stat
)
2859 * Update the event value, we cannot use perf_event_read()
2860 * because we're in the middle of a context switch and have IRQs
2861 * disabled, which upsets smp_call_function_single(), however
2862 * we know the event must be on the current CPU, therefore we
2863 * don't need to use it.
2865 switch (event
->state
) {
2866 case PERF_EVENT_STATE_ACTIVE
:
2867 event
->pmu
->read(event
);
2870 case PERF_EVENT_STATE_INACTIVE
:
2871 update_event_times(event
);
2879 * In order to keep per-task stats reliable we need to flip the event
2880 * values when we flip the contexts.
2882 value
= local64_read(&next_event
->count
);
2883 value
= local64_xchg(&event
->count
, value
);
2884 local64_set(&next_event
->count
, value
);
2886 swap(event
->total_time_enabled
, next_event
->total_time_enabled
);
2887 swap(event
->total_time_running
, next_event
->total_time_running
);
2890 * Since we swizzled the values, update the user visible data too.
2892 perf_event_update_userpage(event
);
2893 perf_event_update_userpage(next_event
);
2896 static void perf_event_sync_stat(struct perf_event_context
*ctx
,
2897 struct perf_event_context
*next_ctx
)
2899 struct perf_event
*event
, *next_event
;
2904 update_context_time(ctx
);
2906 event
= list_first_entry(&ctx
->event_list
,
2907 struct perf_event
, event_entry
);
2909 next_event
= list_first_entry(&next_ctx
->event_list
,
2910 struct perf_event
, event_entry
);
2912 while (&event
->event_entry
!= &ctx
->event_list
&&
2913 &next_event
->event_entry
!= &next_ctx
->event_list
) {
2915 __perf_event_sync_stat(event
, next_event
);
2917 event
= list_next_entry(event
, event_entry
);
2918 next_event
= list_next_entry(next_event
, event_entry
);
2922 static void perf_event_context_sched_out(struct task_struct
*task
, int ctxn
,
2923 struct task_struct
*next
)
2925 struct perf_event_context
*ctx
= task
->perf_event_ctxp
[ctxn
];
2926 struct perf_event_context
*next_ctx
;
2927 struct perf_event_context
*parent
, *next_parent
;
2928 struct perf_cpu_context
*cpuctx
;
2934 cpuctx
= __get_cpu_context(ctx
);
2935 if (!cpuctx
->task_ctx
)
2939 next_ctx
= next
->perf_event_ctxp
[ctxn
];
2943 parent
= rcu_dereference(ctx
->parent_ctx
);
2944 next_parent
= rcu_dereference(next_ctx
->parent_ctx
);
2946 /* If neither context have a parent context; they cannot be clones. */
2947 if (!parent
&& !next_parent
)
2950 if (next_parent
== ctx
|| next_ctx
== parent
|| next_parent
== parent
) {
2952 * Looks like the two contexts are clones, so we might be
2953 * able to optimize the context switch. We lock both
2954 * contexts and check that they are clones under the
2955 * lock (including re-checking that neither has been
2956 * uncloned in the meantime). It doesn't matter which
2957 * order we take the locks because no other cpu could
2958 * be trying to lock both of these tasks.
2960 raw_spin_lock(&ctx
->lock
);
2961 raw_spin_lock_nested(&next_ctx
->lock
, SINGLE_DEPTH_NESTING
);
2962 if (context_equiv(ctx
, next_ctx
)) {
2963 WRITE_ONCE(ctx
->task
, next
);
2964 WRITE_ONCE(next_ctx
->task
, task
);
2966 swap(ctx
->task_ctx_data
, next_ctx
->task_ctx_data
);
2969 * RCU_INIT_POINTER here is safe because we've not
2970 * modified the ctx and the above modification of
2971 * ctx->task and ctx->task_ctx_data are immaterial
2972 * since those values are always verified under
2973 * ctx->lock which we're now holding.
2975 RCU_INIT_POINTER(task
->perf_event_ctxp
[ctxn
], next_ctx
);
2976 RCU_INIT_POINTER(next
->perf_event_ctxp
[ctxn
], ctx
);
2980 perf_event_sync_stat(ctx
, next_ctx
);
2982 raw_spin_unlock(&next_ctx
->lock
);
2983 raw_spin_unlock(&ctx
->lock
);
2989 raw_spin_lock(&ctx
->lock
);
2990 task_ctx_sched_out(cpuctx
, ctx
, EVENT_ALL
);
2991 raw_spin_unlock(&ctx
->lock
);
2995 static DEFINE_PER_CPU(struct list_head
, sched_cb_list
);
2997 void perf_sched_cb_dec(struct pmu
*pmu
)
2999 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
3001 this_cpu_dec(perf_sched_cb_usages
);
3003 if (!--cpuctx
->sched_cb_usage
)
3004 list_del(&cpuctx
->sched_cb_entry
);
3008 void perf_sched_cb_inc(struct pmu
*pmu
)
3010 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
3012 if (!cpuctx
->sched_cb_usage
++)
3013 list_add(&cpuctx
->sched_cb_entry
, this_cpu_ptr(&sched_cb_list
));
3015 this_cpu_inc(perf_sched_cb_usages
);
3019 * This function provides the context switch callback to the lower code
3020 * layer. It is invoked ONLY when the context switch callback is enabled.
3022 * This callback is relevant even to per-cpu events; for example multi event
3023 * PEBS requires this to provide PID/TID information. This requires we flush
3024 * all queued PEBS records before we context switch to a new task.
3026 static void perf_pmu_sched_task(struct task_struct
*prev
,
3027 struct task_struct
*next
,
3030 struct perf_cpu_context
*cpuctx
;
3036 list_for_each_entry(cpuctx
, this_cpu_ptr(&sched_cb_list
), sched_cb_entry
) {
3037 pmu
= cpuctx
->ctx
.pmu
; /* software PMUs will not have sched_task */
3039 if (WARN_ON_ONCE(!pmu
->sched_task
))
3042 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
3043 perf_pmu_disable(pmu
);
3045 pmu
->sched_task(cpuctx
->task_ctx
, sched_in
);
3047 perf_pmu_enable(pmu
);
3048 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
3052 static void perf_event_switch(struct task_struct
*task
,
3053 struct task_struct
*next_prev
, bool sched_in
);
3055 #define for_each_task_context_nr(ctxn) \
3056 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3059 * Called from scheduler to remove the events of the current task,
3060 * with interrupts disabled.
3062 * We stop each event and update the event value in event->count.
3064 * This does not protect us against NMI, but disable()
3065 * sets the disabled bit in the control field of event _before_
3066 * accessing the event control register. If a NMI hits, then it will
3067 * not restart the event.
3069 void __perf_event_task_sched_out(struct task_struct
*task
,
3070 struct task_struct
*next
)
3074 if (__this_cpu_read(perf_sched_cb_usages
))
3075 perf_pmu_sched_task(task
, next
, false);
3077 if (atomic_read(&nr_switch_events
))
3078 perf_event_switch(task
, next
, false);
3080 for_each_task_context_nr(ctxn
)
3081 perf_event_context_sched_out(task
, ctxn
, next
);
3084 * if cgroup events exist on this CPU, then we need
3085 * to check if we have to switch out PMU state.
3086 * cgroup event are system-wide mode only
3088 if (atomic_read(this_cpu_ptr(&perf_cgroup_events
)))
3089 perf_cgroup_sched_out(task
, next
);
3093 * Called with IRQs disabled
3095 static void cpu_ctx_sched_out(struct perf_cpu_context
*cpuctx
,
3096 enum event_type_t event_type
)
3098 ctx_sched_out(&cpuctx
->ctx
, cpuctx
, event_type
);
3102 ctx_pinned_sched_in(struct perf_event_context
*ctx
,
3103 struct perf_cpu_context
*cpuctx
)
3105 struct perf_event
*event
;
3107 list_for_each_entry(event
, &ctx
->pinned_groups
, group_entry
) {
3108 if (event
->state
<= PERF_EVENT_STATE_OFF
)
3110 if (!event_filter_match(event
))
3113 /* may need to reset tstamp_enabled */
3114 if (is_cgroup_event(event
))
3115 perf_cgroup_mark_enabled(event
, ctx
);
3117 if (group_can_go_on(event
, cpuctx
, 1))
3118 group_sched_in(event
, cpuctx
, ctx
);
3121 * If this pinned group hasn't been scheduled,
3122 * put it in error state.
3124 if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
3125 update_group_times(event
);
3126 event
->state
= PERF_EVENT_STATE_ERROR
;
3132 ctx_flexible_sched_in(struct perf_event_context
*ctx
,
3133 struct perf_cpu_context
*cpuctx
)
3135 struct perf_event
*event
;
3138 list_for_each_entry(event
, &ctx
->flexible_groups
, group_entry
) {
3139 /* Ignore events in OFF or ERROR state */
3140 if (event
->state
<= PERF_EVENT_STATE_OFF
)
3143 * Listen to the 'cpu' scheduling filter constraint
3146 if (!event_filter_match(event
))
3149 /* may need to reset tstamp_enabled */
3150 if (is_cgroup_event(event
))
3151 perf_cgroup_mark_enabled(event
, ctx
);
3153 if (group_can_go_on(event
, cpuctx
, can_add_hw
)) {
3154 if (group_sched_in(event
, cpuctx
, ctx
))
3161 ctx_sched_in(struct perf_event_context
*ctx
,
3162 struct perf_cpu_context
*cpuctx
,
3163 enum event_type_t event_type
,
3164 struct task_struct
*task
)
3166 int is_active
= ctx
->is_active
;
3169 lockdep_assert_held(&ctx
->lock
);
3171 if (likely(!ctx
->nr_events
))
3174 ctx
->is_active
|= (event_type
| EVENT_TIME
);
3177 cpuctx
->task_ctx
= ctx
;
3179 WARN_ON_ONCE(cpuctx
->task_ctx
!= ctx
);
3182 is_active
^= ctx
->is_active
; /* changed bits */
3184 if (is_active
& EVENT_TIME
) {
3185 /* start ctx time */
3187 ctx
->timestamp
= now
;
3188 perf_cgroup_set_timestamp(task
, ctx
);
3192 * First go through the list and put on any pinned groups
3193 * in order to give them the best chance of going on.
3195 if (is_active
& EVENT_PINNED
)
3196 ctx_pinned_sched_in(ctx
, cpuctx
);
3198 /* Then walk through the lower prio flexible groups */
3199 if (is_active
& EVENT_FLEXIBLE
)
3200 ctx_flexible_sched_in(ctx
, cpuctx
);
3203 static void cpu_ctx_sched_in(struct perf_cpu_context
*cpuctx
,
3204 enum event_type_t event_type
,
3205 struct task_struct
*task
)
3207 struct perf_event_context
*ctx
= &cpuctx
->ctx
;
3209 ctx_sched_in(ctx
, cpuctx
, event_type
, task
);
3212 static void perf_event_context_sched_in(struct perf_event_context
*ctx
,
3213 struct task_struct
*task
)
3215 struct perf_cpu_context
*cpuctx
;
3217 cpuctx
= __get_cpu_context(ctx
);
3218 if (cpuctx
->task_ctx
== ctx
)
3221 perf_ctx_lock(cpuctx
, ctx
);
3223 * We must check ctx->nr_events while holding ctx->lock, such
3224 * that we serialize against perf_install_in_context().
3226 if (!ctx
->nr_events
)
3229 perf_pmu_disable(ctx
->pmu
);
3231 * We want to keep the following priority order:
3232 * cpu pinned (that don't need to move), task pinned,
3233 * cpu flexible, task flexible.
3235 * However, if task's ctx is not carrying any pinned
3236 * events, no need to flip the cpuctx's events around.
3238 if (!list_empty(&ctx
->pinned_groups
))
3239 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
3240 perf_event_sched_in(cpuctx
, ctx
, task
);
3241 perf_pmu_enable(ctx
->pmu
);
3244 perf_ctx_unlock(cpuctx
, ctx
);
3248 * Called from scheduler to add the events of the current task
3249 * with interrupts disabled.
3251 * We restore the event value and then enable it.
3253 * This does not protect us against NMI, but enable()
3254 * sets the enabled bit in the control field of event _before_
3255 * accessing the event control register. If a NMI hits, then it will
3256 * keep the event running.
3258 void __perf_event_task_sched_in(struct task_struct
*prev
,
3259 struct task_struct
*task
)
3261 struct perf_event_context
*ctx
;
3265 * If cgroup events exist on this CPU, then we need to check if we have
3266 * to switch in PMU state; cgroup event are system-wide mode only.
3268 * Since cgroup events are CPU events, we must schedule these in before
3269 * we schedule in the task events.
3271 if (atomic_read(this_cpu_ptr(&perf_cgroup_events
)))
3272 perf_cgroup_sched_in(prev
, task
);
3274 for_each_task_context_nr(ctxn
) {
3275 ctx
= task
->perf_event_ctxp
[ctxn
];
3279 perf_event_context_sched_in(ctx
, task
);
3282 if (atomic_read(&nr_switch_events
))
3283 perf_event_switch(task
, prev
, true);
3285 if (__this_cpu_read(perf_sched_cb_usages
))
3286 perf_pmu_sched_task(prev
, task
, true);
3289 static u64
perf_calculate_period(struct perf_event
*event
, u64 nsec
, u64 count
)
3291 u64 frequency
= event
->attr
.sample_freq
;
3292 u64 sec
= NSEC_PER_SEC
;
3293 u64 divisor
, dividend
;
3295 int count_fls
, nsec_fls
, frequency_fls
, sec_fls
;
3297 count_fls
= fls64(count
);
3298 nsec_fls
= fls64(nsec
);
3299 frequency_fls
= fls64(frequency
);
3303 * We got @count in @nsec, with a target of sample_freq HZ
3304 * the target period becomes:
3307 * period = -------------------
3308 * @nsec * sample_freq
3313 * Reduce accuracy by one bit such that @a and @b converge
3314 * to a similar magnitude.
3316 #define REDUCE_FLS(a, b) \
3318 if (a##_fls > b##_fls) { \
3328 * Reduce accuracy until either term fits in a u64, then proceed with
3329 * the other, so that finally we can do a u64/u64 division.
3331 while (count_fls
+ sec_fls
> 64 && nsec_fls
+ frequency_fls
> 64) {
3332 REDUCE_FLS(nsec
, frequency
);
3333 REDUCE_FLS(sec
, count
);
3336 if (count_fls
+ sec_fls
> 64) {
3337 divisor
= nsec
* frequency
;
3339 while (count_fls
+ sec_fls
> 64) {
3340 REDUCE_FLS(count
, sec
);
3344 dividend
= count
* sec
;
3346 dividend
= count
* sec
;
3348 while (nsec_fls
+ frequency_fls
> 64) {
3349 REDUCE_FLS(nsec
, frequency
);
3353 divisor
= nsec
* frequency
;
3359 return div64_u64(dividend
, divisor
);
3362 static DEFINE_PER_CPU(int, perf_throttled_count
);
3363 static DEFINE_PER_CPU(u64
, perf_throttled_seq
);
3365 static void perf_adjust_period(struct perf_event
*event
, u64 nsec
, u64 count
, bool disable
)
3367 struct hw_perf_event
*hwc
= &event
->hw
;
3368 s64 period
, sample_period
;
3371 period
= perf_calculate_period(event
, nsec
, count
);
3373 delta
= (s64
)(period
- hwc
->sample_period
);
3374 delta
= (delta
+ 7) / 8; /* low pass filter */
3376 sample_period
= hwc
->sample_period
+ delta
;
3381 hwc
->sample_period
= sample_period
;
3383 if (local64_read(&hwc
->period_left
) > 8*sample_period
) {
3385 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
3387 local64_set(&hwc
->period_left
, 0);
3390 event
->pmu
->start(event
, PERF_EF_RELOAD
);
3395 * combine freq adjustment with unthrottling to avoid two passes over the
3396 * events. At the same time, make sure, having freq events does not change
3397 * the rate of unthrottling as that would introduce bias.
3399 static void perf_adjust_freq_unthr_context(struct perf_event_context
*ctx
,
3402 struct perf_event
*event
;
3403 struct hw_perf_event
*hwc
;
3404 u64 now
, period
= TICK_NSEC
;
3408 * only need to iterate over all events iff:
3409 * - context have events in frequency mode (needs freq adjust)
3410 * - there are events to unthrottle on this cpu
3412 if (!(ctx
->nr_freq
|| needs_unthr
))
3415 raw_spin_lock(&ctx
->lock
);
3416 perf_pmu_disable(ctx
->pmu
);
3418 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
3419 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
3422 if (!event_filter_match(event
))
3425 perf_pmu_disable(event
->pmu
);
3429 if (hwc
->interrupts
== MAX_INTERRUPTS
) {
3430 hwc
->interrupts
= 0;
3431 perf_log_throttle(event
, 1);
3432 event
->pmu
->start(event
, 0);
3435 if (!event
->attr
.freq
|| !event
->attr
.sample_freq
)
3439 * stop the event and update event->count
3441 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
3443 now
= local64_read(&event
->count
);
3444 delta
= now
- hwc
->freq_count_stamp
;
3445 hwc
->freq_count_stamp
= now
;
3449 * reload only if value has changed
3450 * we have stopped the event so tell that
3451 * to perf_adjust_period() to avoid stopping it
3455 perf_adjust_period(event
, period
, delta
, false);
3457 event
->pmu
->start(event
, delta
> 0 ? PERF_EF_RELOAD
: 0);
3459 perf_pmu_enable(event
->pmu
);
3462 perf_pmu_enable(ctx
->pmu
);
3463 raw_spin_unlock(&ctx
->lock
);
3467 * Round-robin a context's events:
3469 static void rotate_ctx(struct perf_event_context
*ctx
)
3472 * Rotate the first entry last of non-pinned groups. Rotation might be
3473 * disabled by the inheritance code.
3475 if (!ctx
->rotate_disable
)
3476 list_rotate_left(&ctx
->flexible_groups
);
3479 static int perf_rotate_context(struct perf_cpu_context
*cpuctx
)
3481 struct perf_event_context
*ctx
= NULL
;
3484 if (cpuctx
->ctx
.nr_events
) {
3485 if (cpuctx
->ctx
.nr_events
!= cpuctx
->ctx
.nr_active
)
3489 ctx
= cpuctx
->task_ctx
;
3490 if (ctx
&& ctx
->nr_events
) {
3491 if (ctx
->nr_events
!= ctx
->nr_active
)
3498 perf_ctx_lock(cpuctx
, cpuctx
->task_ctx
);
3499 perf_pmu_disable(cpuctx
->ctx
.pmu
);
3501 cpu_ctx_sched_out(cpuctx
, EVENT_FLEXIBLE
);
3503 ctx_sched_out(ctx
, cpuctx
, EVENT_FLEXIBLE
);
3505 rotate_ctx(&cpuctx
->ctx
);
3509 perf_event_sched_in(cpuctx
, ctx
, current
);
3511 perf_pmu_enable(cpuctx
->ctx
.pmu
);
3512 perf_ctx_unlock(cpuctx
, cpuctx
->task_ctx
);
3518 void perf_event_task_tick(void)
3520 struct list_head
*head
= this_cpu_ptr(&active_ctx_list
);
3521 struct perf_event_context
*ctx
, *tmp
;
3524 WARN_ON(!irqs_disabled());
3526 __this_cpu_inc(perf_throttled_seq
);
3527 throttled
= __this_cpu_xchg(perf_throttled_count
, 0);
3528 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS
);
3530 list_for_each_entry_safe(ctx
, tmp
, head
, active_ctx_list
)
3531 perf_adjust_freq_unthr_context(ctx
, throttled
);
3534 static int event_enable_on_exec(struct perf_event
*event
,
3535 struct perf_event_context
*ctx
)
3537 if (!event
->attr
.enable_on_exec
)
3540 event
->attr
.enable_on_exec
= 0;
3541 if (event
->state
>= PERF_EVENT_STATE_INACTIVE
)
3544 __perf_event_mark_enabled(event
);
3550 * Enable all of a task's events that have been marked enable-on-exec.
3551 * This expects task == current.
3553 static void perf_event_enable_on_exec(int ctxn
)
3555 struct perf_event_context
*ctx
, *clone_ctx
= NULL
;
3556 enum event_type_t event_type
= 0;
3557 struct perf_cpu_context
*cpuctx
;
3558 struct perf_event
*event
;
3559 unsigned long flags
;
3562 local_irq_save(flags
);
3563 ctx
= current
->perf_event_ctxp
[ctxn
];
3564 if (!ctx
|| !ctx
->nr_events
)
3567 cpuctx
= __get_cpu_context(ctx
);
3568 perf_ctx_lock(cpuctx
, ctx
);
3569 ctx_sched_out(ctx
, cpuctx
, EVENT_TIME
);
3570 list_for_each_entry(event
, &ctx
->event_list
, event_entry
) {
3571 enabled
|= event_enable_on_exec(event
, ctx
);
3572 event_type
|= get_event_type(event
);
3576 * Unclone and reschedule this context if we enabled any event.
3579 clone_ctx
= unclone_ctx(ctx
);
3580 ctx_resched(cpuctx
, ctx
, event_type
);
3582 ctx_sched_in(ctx
, cpuctx
, EVENT_TIME
, current
);
3584 perf_ctx_unlock(cpuctx
, ctx
);
3587 local_irq_restore(flags
);
3593 struct perf_read_data
{
3594 struct perf_event
*event
;
3599 static int __perf_event_read_cpu(struct perf_event
*event
, int event_cpu
)
3601 u16 local_pkg
, event_pkg
;
3603 if (event
->group_caps
& PERF_EV_CAP_READ_ACTIVE_PKG
) {
3604 int local_cpu
= smp_processor_id();
3606 event_pkg
= topology_physical_package_id(event_cpu
);
3607 local_pkg
= topology_physical_package_id(local_cpu
);
3609 if (event_pkg
== local_pkg
)
3617 * Cross CPU call to read the hardware event
3619 static void __perf_event_read(void *info
)
3621 struct perf_read_data
*data
= info
;
3622 struct perf_event
*sub
, *event
= data
->event
;
3623 struct perf_event_context
*ctx
= event
->ctx
;
3624 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
3625 struct pmu
*pmu
= event
->pmu
;
3628 * If this is a task context, we need to check whether it is
3629 * the current task context of this cpu. If not it has been
3630 * scheduled out before the smp call arrived. In that case
3631 * event->count would have been updated to a recent sample
3632 * when the event was scheduled out.
3634 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
3637 raw_spin_lock(&ctx
->lock
);
3638 if (ctx
->is_active
) {
3639 update_context_time(ctx
);
3640 update_cgrp_time_from_event(event
);
3643 update_event_times(event
);
3644 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
3653 pmu
->start_txn(pmu
, PERF_PMU_TXN_READ
);
3657 list_for_each_entry(sub
, &event
->sibling_list
, group_entry
) {
3658 update_event_times(sub
);
3659 if (sub
->state
== PERF_EVENT_STATE_ACTIVE
) {
3661 * Use sibling's PMU rather than @event's since
3662 * sibling could be on different (eg: software) PMU.
3664 sub
->pmu
->read(sub
);
3668 data
->ret
= pmu
->commit_txn(pmu
);
3671 raw_spin_unlock(&ctx
->lock
);
3674 static inline u64
perf_event_count(struct perf_event
*event
)
3676 return local64_read(&event
->count
) + atomic64_read(&event
->child_count
);
3680 * NMI-safe method to read a local event, that is an event that
3682 * - either for the current task, or for this CPU
3683 * - does not have inherit set, for inherited task events
3684 * will not be local and we cannot read them atomically
3685 * - must not have a pmu::count method
3687 int perf_event_read_local(struct perf_event
*event
, u64
*value
)
3689 unsigned long flags
;
3693 * Disabling interrupts avoids all counter scheduling (context
3694 * switches, timer based rotation and IPIs).
3696 local_irq_save(flags
);
3699 * It must not be an event with inherit set, we cannot read
3700 * all child counters from atomic context.
3702 if (event
->attr
.inherit
) {
3707 /* If this is a per-task event, it must be for current */
3708 if ((event
->attach_state
& PERF_ATTACH_TASK
) &&
3709 event
->hw
.target
!= current
) {
3714 /* If this is a per-CPU event, it must be for this CPU */
3715 if (!(event
->attach_state
& PERF_ATTACH_TASK
) &&
3716 event
->cpu
!= smp_processor_id()) {
3722 * If the event is currently on this CPU, its either a per-task event,
3723 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3726 if (event
->oncpu
== smp_processor_id())
3727 event
->pmu
->read(event
);
3729 *value
= local64_read(&event
->count
);
3731 local_irq_restore(flags
);
3736 static int perf_event_read(struct perf_event
*event
, bool group
)
3738 int event_cpu
, ret
= 0;
3741 * If event is enabled and currently active on a CPU, update the
3742 * value in the event structure:
3744 if (event
->state
== PERF_EVENT_STATE_ACTIVE
) {
3745 struct perf_read_data data
= {
3751 event_cpu
= READ_ONCE(event
->oncpu
);
3752 if ((unsigned)event_cpu
>= nr_cpu_ids
)
3756 event_cpu
= __perf_event_read_cpu(event
, event_cpu
);
3759 * Purposely ignore the smp_call_function_single() return
3762 * If event_cpu isn't a valid CPU it means the event got
3763 * scheduled out and that will have updated the event count.
3765 * Therefore, either way, we'll have an up-to-date event count
3768 (void)smp_call_function_single(event_cpu
, __perf_event_read
, &data
, 1);
3771 } else if (event
->state
== PERF_EVENT_STATE_INACTIVE
) {
3772 struct perf_event_context
*ctx
= event
->ctx
;
3773 unsigned long flags
;
3775 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
3777 * may read while context is not active
3778 * (e.g., thread is blocked), in that case
3779 * we cannot update context time
3781 if (ctx
->is_active
) {
3782 update_context_time(ctx
);
3783 update_cgrp_time_from_event(event
);
3786 update_group_times(event
);
3788 update_event_times(event
);
3789 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
3796 * Initialize the perf_event context in a task_struct:
3798 static void __perf_event_init_context(struct perf_event_context
*ctx
)
3800 raw_spin_lock_init(&ctx
->lock
);
3801 mutex_init(&ctx
->mutex
);
3802 INIT_LIST_HEAD(&ctx
->active_ctx_list
);
3803 INIT_LIST_HEAD(&ctx
->pinned_groups
);
3804 INIT_LIST_HEAD(&ctx
->flexible_groups
);
3805 INIT_LIST_HEAD(&ctx
->event_list
);
3806 atomic_set(&ctx
->refcount
, 1);
3809 static struct perf_event_context
*
3810 alloc_perf_context(struct pmu
*pmu
, struct task_struct
*task
)
3812 struct perf_event_context
*ctx
;
3814 ctx
= kzalloc(sizeof(struct perf_event_context
), GFP_KERNEL
);
3818 __perf_event_init_context(ctx
);
3821 get_task_struct(task
);
3828 static struct task_struct
*
3829 find_lively_task_by_vpid(pid_t vpid
)
3831 struct task_struct
*task
;
3837 task
= find_task_by_vpid(vpid
);
3839 get_task_struct(task
);
3843 return ERR_PTR(-ESRCH
);
3849 * Returns a matching context with refcount and pincount.
3851 static struct perf_event_context
*
3852 find_get_context(struct pmu
*pmu
, struct task_struct
*task
,
3853 struct perf_event
*event
)
3855 struct perf_event_context
*ctx
, *clone_ctx
= NULL
;
3856 struct perf_cpu_context
*cpuctx
;
3857 void *task_ctx_data
= NULL
;
3858 unsigned long flags
;
3860 int cpu
= event
->cpu
;
3863 /* Must be root to operate on a CPU event: */
3864 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN
))
3865 return ERR_PTR(-EACCES
);
3867 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
3876 ctxn
= pmu
->task_ctx_nr
;
3880 if (event
->attach_state
& PERF_ATTACH_TASK_DATA
) {
3881 task_ctx_data
= kzalloc(pmu
->task_ctx_size
, GFP_KERNEL
);
3882 if (!task_ctx_data
) {
3889 ctx
= perf_lock_task_context(task
, ctxn
, &flags
);
3891 clone_ctx
= unclone_ctx(ctx
);
3894 if (task_ctx_data
&& !ctx
->task_ctx_data
) {
3895 ctx
->task_ctx_data
= task_ctx_data
;
3896 task_ctx_data
= NULL
;
3898 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
3903 ctx
= alloc_perf_context(pmu
, task
);
3908 if (task_ctx_data
) {
3909 ctx
->task_ctx_data
= task_ctx_data
;
3910 task_ctx_data
= NULL
;
3914 mutex_lock(&task
->perf_event_mutex
);
3916 * If it has already passed perf_event_exit_task().
3917 * we must see PF_EXITING, it takes this mutex too.
3919 if (task
->flags
& PF_EXITING
)
3921 else if (task
->perf_event_ctxp
[ctxn
])
3926 rcu_assign_pointer(task
->perf_event_ctxp
[ctxn
], ctx
);
3928 mutex_unlock(&task
->perf_event_mutex
);
3930 if (unlikely(err
)) {
3939 kfree(task_ctx_data
);
3943 kfree(task_ctx_data
);
3944 return ERR_PTR(err
);
3947 static void perf_event_free_filter(struct perf_event
*event
);
3948 static void perf_event_free_bpf_prog(struct perf_event
*event
);
3950 static void free_event_rcu(struct rcu_head
*head
)
3952 struct perf_event
*event
;
3954 event
= container_of(head
, struct perf_event
, rcu_head
);
3956 put_pid_ns(event
->ns
);
3957 perf_event_free_filter(event
);
3961 static void ring_buffer_attach(struct perf_event
*event
,
3962 struct ring_buffer
*rb
);
3964 static void detach_sb_event(struct perf_event
*event
)
3966 struct pmu_event_list
*pel
= per_cpu_ptr(&pmu_sb_events
, event
->cpu
);
3968 raw_spin_lock(&pel
->lock
);
3969 list_del_rcu(&event
->sb_list
);
3970 raw_spin_unlock(&pel
->lock
);
3973 static bool is_sb_event(struct perf_event
*event
)
3975 struct perf_event_attr
*attr
= &event
->attr
;
3980 if (event
->attach_state
& PERF_ATTACH_TASK
)
3983 if (attr
->mmap
|| attr
->mmap_data
|| attr
->mmap2
||
3984 attr
->comm
|| attr
->comm_exec
||
3986 attr
->context_switch
)
3991 static void unaccount_pmu_sb_event(struct perf_event
*event
)
3993 if (is_sb_event(event
))
3994 detach_sb_event(event
);
3997 static void unaccount_event_cpu(struct perf_event
*event
, int cpu
)
4002 if (is_cgroup_event(event
))
4003 atomic_dec(&per_cpu(perf_cgroup_events
, cpu
));
4006 #ifdef CONFIG_NO_HZ_FULL
4007 static DEFINE_SPINLOCK(nr_freq_lock
);
4010 static void unaccount_freq_event_nohz(void)
4012 #ifdef CONFIG_NO_HZ_FULL
4013 spin_lock(&nr_freq_lock
);
4014 if (atomic_dec_and_test(&nr_freq_events
))
4015 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS
);
4016 spin_unlock(&nr_freq_lock
);
4020 static void unaccount_freq_event(void)
4022 if (tick_nohz_full_enabled())
4023 unaccount_freq_event_nohz();
4025 atomic_dec(&nr_freq_events
);
4028 static void unaccount_event(struct perf_event
*event
)
4035 if (event
->attach_state
& PERF_ATTACH_TASK
)
4037 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
4038 atomic_dec(&nr_mmap_events
);
4039 if (event
->attr
.comm
)
4040 atomic_dec(&nr_comm_events
);
4041 if (event
->attr
.namespaces
)
4042 atomic_dec(&nr_namespaces_events
);
4043 if (event
->attr
.task
)
4044 atomic_dec(&nr_task_events
);
4045 if (event
->attr
.freq
)
4046 unaccount_freq_event();
4047 if (event
->attr
.context_switch
) {
4049 atomic_dec(&nr_switch_events
);
4051 if (is_cgroup_event(event
))
4053 if (has_branch_stack(event
))
4057 if (!atomic_add_unless(&perf_sched_count
, -1, 1))
4058 schedule_delayed_work(&perf_sched_work
, HZ
);
4061 unaccount_event_cpu(event
, event
->cpu
);
4063 unaccount_pmu_sb_event(event
);
4066 static void perf_sched_delayed(struct work_struct
*work
)
4068 mutex_lock(&perf_sched_mutex
);
4069 if (atomic_dec_and_test(&perf_sched_count
))
4070 static_branch_disable(&perf_sched_events
);
4071 mutex_unlock(&perf_sched_mutex
);
4075 * The following implement mutual exclusion of events on "exclusive" pmus
4076 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4077 * at a time, so we disallow creating events that might conflict, namely:
4079 * 1) cpu-wide events in the presence of per-task events,
4080 * 2) per-task events in the presence of cpu-wide events,
4081 * 3) two matching events on the same context.
4083 * The former two cases are handled in the allocation path (perf_event_alloc(),
4084 * _free_event()), the latter -- before the first perf_install_in_context().
4086 static int exclusive_event_init(struct perf_event
*event
)
4088 struct pmu
*pmu
= event
->pmu
;
4090 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
4094 * Prevent co-existence of per-task and cpu-wide events on the
4095 * same exclusive pmu.
4097 * Negative pmu::exclusive_cnt means there are cpu-wide
4098 * events on this "exclusive" pmu, positive means there are
4101 * Since this is called in perf_event_alloc() path, event::ctx
4102 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4103 * to mean "per-task event", because unlike other attach states it
4104 * never gets cleared.
4106 if (event
->attach_state
& PERF_ATTACH_TASK
) {
4107 if (!atomic_inc_unless_negative(&pmu
->exclusive_cnt
))
4110 if (!atomic_dec_unless_positive(&pmu
->exclusive_cnt
))
4117 static void exclusive_event_destroy(struct perf_event
*event
)
4119 struct pmu
*pmu
= event
->pmu
;
4121 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
4124 /* see comment in exclusive_event_init() */
4125 if (event
->attach_state
& PERF_ATTACH_TASK
)
4126 atomic_dec(&pmu
->exclusive_cnt
);
4128 atomic_inc(&pmu
->exclusive_cnt
);
4131 static bool exclusive_event_match(struct perf_event
*e1
, struct perf_event
*e2
)
4133 if ((e1
->pmu
== e2
->pmu
) &&
4134 (e1
->cpu
== e2
->cpu
||
4141 /* Called under the same ctx::mutex as perf_install_in_context() */
4142 static bool exclusive_event_installable(struct perf_event
*event
,
4143 struct perf_event_context
*ctx
)
4145 struct perf_event
*iter_event
;
4146 struct pmu
*pmu
= event
->pmu
;
4148 if (!(pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
))
4151 list_for_each_entry(iter_event
, &ctx
->event_list
, event_entry
) {
4152 if (exclusive_event_match(iter_event
, event
))
4159 static void perf_addr_filters_splice(struct perf_event
*event
,
4160 struct list_head
*head
);
4162 static void _free_event(struct perf_event
*event
)
4164 irq_work_sync(&event
->pending
);
4166 unaccount_event(event
);
4170 * Can happen when we close an event with re-directed output.
4172 * Since we have a 0 refcount, perf_mmap_close() will skip
4173 * over us; possibly making our ring_buffer_put() the last.
4175 mutex_lock(&event
->mmap_mutex
);
4176 ring_buffer_attach(event
, NULL
);
4177 mutex_unlock(&event
->mmap_mutex
);
4180 if (is_cgroup_event(event
))
4181 perf_detach_cgroup(event
);
4183 if (!event
->parent
) {
4184 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
)
4185 put_callchain_buffers();
4188 perf_event_free_bpf_prog(event
);
4189 perf_addr_filters_splice(event
, NULL
);
4190 kfree(event
->addr_filters_offs
);
4193 event
->destroy(event
);
4196 put_ctx(event
->ctx
);
4198 exclusive_event_destroy(event
);
4199 module_put(event
->pmu
->module
);
4201 call_rcu(&event
->rcu_head
, free_event_rcu
);
4205 * Used to free events which have a known refcount of 1, such as in error paths
4206 * where the event isn't exposed yet and inherited events.
4208 static void free_event(struct perf_event
*event
)
4210 if (WARN(atomic_long_cmpxchg(&event
->refcount
, 1, 0) != 1,
4211 "unexpected event refcount: %ld; ptr=%p\n",
4212 atomic_long_read(&event
->refcount
), event
)) {
4213 /* leak to avoid use-after-free */
4221 * Remove user event from the owner task.
4223 static void perf_remove_from_owner(struct perf_event
*event
)
4225 struct task_struct
*owner
;
4229 * Matches the smp_store_release() in perf_event_exit_task(). If we
4230 * observe !owner it means the list deletion is complete and we can
4231 * indeed free this event, otherwise we need to serialize on
4232 * owner->perf_event_mutex.
4234 owner
= lockless_dereference(event
->owner
);
4237 * Since delayed_put_task_struct() also drops the last
4238 * task reference we can safely take a new reference
4239 * while holding the rcu_read_lock().
4241 get_task_struct(owner
);
4247 * If we're here through perf_event_exit_task() we're already
4248 * holding ctx->mutex which would be an inversion wrt. the
4249 * normal lock order.
4251 * However we can safely take this lock because its the child
4254 mutex_lock_nested(&owner
->perf_event_mutex
, SINGLE_DEPTH_NESTING
);
4257 * We have to re-check the event->owner field, if it is cleared
4258 * we raced with perf_event_exit_task(), acquiring the mutex
4259 * ensured they're done, and we can proceed with freeing the
4263 list_del_init(&event
->owner_entry
);
4264 smp_store_release(&event
->owner
, NULL
);
4266 mutex_unlock(&owner
->perf_event_mutex
);
4267 put_task_struct(owner
);
4271 static void put_event(struct perf_event
*event
)
4273 if (!atomic_long_dec_and_test(&event
->refcount
))
4280 * Kill an event dead; while event:refcount will preserve the event
4281 * object, it will not preserve its functionality. Once the last 'user'
4282 * gives up the object, we'll destroy the thing.
4284 int perf_event_release_kernel(struct perf_event
*event
)
4286 struct perf_event_context
*ctx
= event
->ctx
;
4287 struct perf_event
*child
, *tmp
;
4290 * If we got here through err_file: fput(event_file); we will not have
4291 * attached to a context yet.
4294 WARN_ON_ONCE(event
->attach_state
&
4295 (PERF_ATTACH_CONTEXT
|PERF_ATTACH_GROUP
));
4299 if (!is_kernel_event(event
))
4300 perf_remove_from_owner(event
);
4302 ctx
= perf_event_ctx_lock(event
);
4303 WARN_ON_ONCE(ctx
->parent_ctx
);
4304 perf_remove_from_context(event
, DETACH_GROUP
);
4306 raw_spin_lock_irq(&ctx
->lock
);
4308 * Mark this event as STATE_DEAD, there is no external reference to it
4311 * Anybody acquiring event->child_mutex after the below loop _must_
4312 * also see this, most importantly inherit_event() which will avoid
4313 * placing more children on the list.
4315 * Thus this guarantees that we will in fact observe and kill _ALL_
4318 event
->state
= PERF_EVENT_STATE_DEAD
;
4319 raw_spin_unlock_irq(&ctx
->lock
);
4321 perf_event_ctx_unlock(event
, ctx
);
4324 mutex_lock(&event
->child_mutex
);
4325 list_for_each_entry(child
, &event
->child_list
, child_list
) {
4328 * Cannot change, child events are not migrated, see the
4329 * comment with perf_event_ctx_lock_nested().
4331 ctx
= lockless_dereference(child
->ctx
);
4333 * Since child_mutex nests inside ctx::mutex, we must jump
4334 * through hoops. We start by grabbing a reference on the ctx.
4336 * Since the event cannot get freed while we hold the
4337 * child_mutex, the context must also exist and have a !0
4343 * Now that we have a ctx ref, we can drop child_mutex, and
4344 * acquire ctx::mutex without fear of it going away. Then we
4345 * can re-acquire child_mutex.
4347 mutex_unlock(&event
->child_mutex
);
4348 mutex_lock(&ctx
->mutex
);
4349 mutex_lock(&event
->child_mutex
);
4352 * Now that we hold ctx::mutex and child_mutex, revalidate our
4353 * state, if child is still the first entry, it didn't get freed
4354 * and we can continue doing so.
4356 tmp
= list_first_entry_or_null(&event
->child_list
,
4357 struct perf_event
, child_list
);
4359 perf_remove_from_context(child
, DETACH_GROUP
);
4360 list_del(&child
->child_list
);
4363 * This matches the refcount bump in inherit_event();
4364 * this can't be the last reference.
4369 mutex_unlock(&event
->child_mutex
);
4370 mutex_unlock(&ctx
->mutex
);
4374 mutex_unlock(&event
->child_mutex
);
4377 put_event(event
); /* Must be the 'last' reference */
4380 EXPORT_SYMBOL_GPL(perf_event_release_kernel
);
4383 * Called when the last reference to the file is gone.
4385 static int perf_release(struct inode
*inode
, struct file
*file
)
4387 perf_event_release_kernel(file
->private_data
);
4391 u64
perf_event_read_value(struct perf_event
*event
, u64
*enabled
, u64
*running
)
4393 struct perf_event
*child
;
4399 mutex_lock(&event
->child_mutex
);
4401 (void)perf_event_read(event
, false);
4402 total
+= perf_event_count(event
);
4404 *enabled
+= event
->total_time_enabled
+
4405 atomic64_read(&event
->child_total_time_enabled
);
4406 *running
+= event
->total_time_running
+
4407 atomic64_read(&event
->child_total_time_running
);
4409 list_for_each_entry(child
, &event
->child_list
, child_list
) {
4410 (void)perf_event_read(child
, false);
4411 total
+= perf_event_count(child
);
4412 *enabled
+= child
->total_time_enabled
;
4413 *running
+= child
->total_time_running
;
4415 mutex_unlock(&event
->child_mutex
);
4419 EXPORT_SYMBOL_GPL(perf_event_read_value
);
4421 static int __perf_read_group_add(struct perf_event
*leader
,
4422 u64 read_format
, u64
*values
)
4424 struct perf_event_context
*ctx
= leader
->ctx
;
4425 struct perf_event
*sub
;
4426 unsigned long flags
;
4427 int n
= 1; /* skip @nr */
4430 ret
= perf_event_read(leader
, true);
4435 * Since we co-schedule groups, {enabled,running} times of siblings
4436 * will be identical to those of the leader, so we only publish one
4439 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
4440 values
[n
++] += leader
->total_time_enabled
+
4441 atomic64_read(&leader
->child_total_time_enabled
);
4444 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
4445 values
[n
++] += leader
->total_time_running
+
4446 atomic64_read(&leader
->child_total_time_running
);
4450 * Write {count,id} tuples for every sibling.
4452 values
[n
++] += perf_event_count(leader
);
4453 if (read_format
& PERF_FORMAT_ID
)
4454 values
[n
++] = primary_event_id(leader
);
4456 raw_spin_lock_irqsave(&ctx
->lock
, flags
);
4458 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
4459 values
[n
++] += perf_event_count(sub
);
4460 if (read_format
& PERF_FORMAT_ID
)
4461 values
[n
++] = primary_event_id(sub
);
4464 raw_spin_unlock_irqrestore(&ctx
->lock
, flags
);
4468 static int perf_read_group(struct perf_event
*event
,
4469 u64 read_format
, char __user
*buf
)
4471 struct perf_event
*leader
= event
->group_leader
, *child
;
4472 struct perf_event_context
*ctx
= leader
->ctx
;
4476 lockdep_assert_held(&ctx
->mutex
);
4478 values
= kzalloc(event
->read_size
, GFP_KERNEL
);
4482 values
[0] = 1 + leader
->nr_siblings
;
4485 * By locking the child_mutex of the leader we effectively
4486 * lock the child list of all siblings.. XXX explain how.
4488 mutex_lock(&leader
->child_mutex
);
4490 ret
= __perf_read_group_add(leader
, read_format
, values
);
4494 list_for_each_entry(child
, &leader
->child_list
, child_list
) {
4495 ret
= __perf_read_group_add(child
, read_format
, values
);
4500 mutex_unlock(&leader
->child_mutex
);
4502 ret
= event
->read_size
;
4503 if (copy_to_user(buf
, values
, event
->read_size
))
4508 mutex_unlock(&leader
->child_mutex
);
4514 static int perf_read_one(struct perf_event
*event
,
4515 u64 read_format
, char __user
*buf
)
4517 u64 enabled
, running
;
4521 values
[n
++] = perf_event_read_value(event
, &enabled
, &running
);
4522 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
4523 values
[n
++] = enabled
;
4524 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
4525 values
[n
++] = running
;
4526 if (read_format
& PERF_FORMAT_ID
)
4527 values
[n
++] = primary_event_id(event
);
4529 if (copy_to_user(buf
, values
, n
* sizeof(u64
)))
4532 return n
* sizeof(u64
);
4535 static bool is_event_hup(struct perf_event
*event
)
4539 if (event
->state
> PERF_EVENT_STATE_EXIT
)
4542 mutex_lock(&event
->child_mutex
);
4543 no_children
= list_empty(&event
->child_list
);
4544 mutex_unlock(&event
->child_mutex
);
4549 * Read the performance event - simple non blocking version for now
4552 __perf_read(struct perf_event
*event
, char __user
*buf
, size_t count
)
4554 u64 read_format
= event
->attr
.read_format
;
4558 * Return end-of-file for a read on a event that is in
4559 * error state (i.e. because it was pinned but it couldn't be
4560 * scheduled on to the CPU at some point).
4562 if (event
->state
== PERF_EVENT_STATE_ERROR
)
4565 if (count
< event
->read_size
)
4568 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
4569 if (read_format
& PERF_FORMAT_GROUP
)
4570 ret
= perf_read_group(event
, read_format
, buf
);
4572 ret
= perf_read_one(event
, read_format
, buf
);
4578 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
4580 struct perf_event
*event
= file
->private_data
;
4581 struct perf_event_context
*ctx
;
4584 ctx
= perf_event_ctx_lock(event
);
4585 ret
= __perf_read(event
, buf
, count
);
4586 perf_event_ctx_unlock(event
, ctx
);
4591 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
4593 struct perf_event
*event
= file
->private_data
;
4594 struct ring_buffer
*rb
;
4595 unsigned int events
= POLLHUP
;
4597 poll_wait(file
, &event
->waitq
, wait
);
4599 if (is_event_hup(event
))
4603 * Pin the event->rb by taking event->mmap_mutex; otherwise
4604 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4606 mutex_lock(&event
->mmap_mutex
);
4609 events
= atomic_xchg(&rb
->poll
, 0);
4610 mutex_unlock(&event
->mmap_mutex
);
4614 static void _perf_event_reset(struct perf_event
*event
)
4616 (void)perf_event_read(event
, false);
4617 local64_set(&event
->count
, 0);
4618 perf_event_update_userpage(event
);
4622 * Holding the top-level event's child_mutex means that any
4623 * descendant process that has inherited this event will block
4624 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4625 * task existence requirements of perf_event_enable/disable.
4627 static void perf_event_for_each_child(struct perf_event
*event
,
4628 void (*func
)(struct perf_event
*))
4630 struct perf_event
*child
;
4632 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
4634 mutex_lock(&event
->child_mutex
);
4636 list_for_each_entry(child
, &event
->child_list
, child_list
)
4638 mutex_unlock(&event
->child_mutex
);
4641 static void perf_event_for_each(struct perf_event
*event
,
4642 void (*func
)(struct perf_event
*))
4644 struct perf_event_context
*ctx
= event
->ctx
;
4645 struct perf_event
*sibling
;
4647 lockdep_assert_held(&ctx
->mutex
);
4649 event
= event
->group_leader
;
4651 perf_event_for_each_child(event
, func
);
4652 list_for_each_entry(sibling
, &event
->sibling_list
, group_entry
)
4653 perf_event_for_each_child(sibling
, func
);
4656 static void __perf_event_period(struct perf_event
*event
,
4657 struct perf_cpu_context
*cpuctx
,
4658 struct perf_event_context
*ctx
,
4661 u64 value
= *((u64
*)info
);
4664 if (event
->attr
.freq
) {
4665 event
->attr
.sample_freq
= value
;
4667 event
->attr
.sample_period
= value
;
4668 event
->hw
.sample_period
= value
;
4671 active
= (event
->state
== PERF_EVENT_STATE_ACTIVE
);
4673 perf_pmu_disable(ctx
->pmu
);
4675 * We could be throttled; unthrottle now to avoid the tick
4676 * trying to unthrottle while we already re-started the event.
4678 if (event
->hw
.interrupts
== MAX_INTERRUPTS
) {
4679 event
->hw
.interrupts
= 0;
4680 perf_log_throttle(event
, 1);
4682 event
->pmu
->stop(event
, PERF_EF_UPDATE
);
4685 local64_set(&event
->hw
.period_left
, 0);
4688 event
->pmu
->start(event
, PERF_EF_RELOAD
);
4689 perf_pmu_enable(ctx
->pmu
);
4693 static int perf_event_period(struct perf_event
*event
, u64 __user
*arg
)
4697 if (!is_sampling_event(event
))
4700 if (copy_from_user(&value
, arg
, sizeof(value
)))
4706 if (event
->attr
.freq
&& value
> sysctl_perf_event_sample_rate
)
4709 event_function_call(event
, __perf_event_period
, &value
);
4714 static const struct file_operations perf_fops
;
4716 static inline int perf_fget_light(int fd
, struct fd
*p
)
4718 struct fd f
= fdget(fd
);
4722 if (f
.file
->f_op
!= &perf_fops
) {
4730 static int perf_event_set_output(struct perf_event
*event
,
4731 struct perf_event
*output_event
);
4732 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
);
4733 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
);
4735 static long _perf_ioctl(struct perf_event
*event
, unsigned int cmd
, unsigned long arg
)
4737 void (*func
)(struct perf_event
*);
4741 case PERF_EVENT_IOC_ENABLE
:
4742 func
= _perf_event_enable
;
4744 case PERF_EVENT_IOC_DISABLE
:
4745 func
= _perf_event_disable
;
4747 case PERF_EVENT_IOC_RESET
:
4748 func
= _perf_event_reset
;
4751 case PERF_EVENT_IOC_REFRESH
:
4752 return _perf_event_refresh(event
, arg
);
4754 case PERF_EVENT_IOC_PERIOD
:
4755 return perf_event_period(event
, (u64 __user
*)arg
);
4757 case PERF_EVENT_IOC_ID
:
4759 u64 id
= primary_event_id(event
);
4761 if (copy_to_user((void __user
*)arg
, &id
, sizeof(id
)))
4766 case PERF_EVENT_IOC_SET_OUTPUT
:
4770 struct perf_event
*output_event
;
4772 ret
= perf_fget_light(arg
, &output
);
4775 output_event
= output
.file
->private_data
;
4776 ret
= perf_event_set_output(event
, output_event
);
4779 ret
= perf_event_set_output(event
, NULL
);
4784 case PERF_EVENT_IOC_SET_FILTER
:
4785 return perf_event_set_filter(event
, (void __user
*)arg
);
4787 case PERF_EVENT_IOC_SET_BPF
:
4788 return perf_event_set_bpf_prog(event
, arg
);
4790 case PERF_EVENT_IOC_PAUSE_OUTPUT
: {
4791 struct ring_buffer
*rb
;
4794 rb
= rcu_dereference(event
->rb
);
4795 if (!rb
|| !rb
->nr_pages
) {
4799 rb_toggle_paused(rb
, !!arg
);
4807 if (flags
& PERF_IOC_FLAG_GROUP
)
4808 perf_event_for_each(event
, func
);
4810 perf_event_for_each_child(event
, func
);
4815 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
4817 struct perf_event
*event
= file
->private_data
;
4818 struct perf_event_context
*ctx
;
4821 ctx
= perf_event_ctx_lock(event
);
4822 ret
= _perf_ioctl(event
, cmd
, arg
);
4823 perf_event_ctx_unlock(event
, ctx
);
4828 #ifdef CONFIG_COMPAT
4829 static long perf_compat_ioctl(struct file
*file
, unsigned int cmd
,
4832 switch (_IOC_NR(cmd
)) {
4833 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER
):
4834 case _IOC_NR(PERF_EVENT_IOC_ID
):
4835 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4836 if (_IOC_SIZE(cmd
) == sizeof(compat_uptr_t
)) {
4837 cmd
&= ~IOCSIZE_MASK
;
4838 cmd
|= sizeof(void *) << IOCSIZE_SHIFT
;
4842 return perf_ioctl(file
, cmd
, arg
);
4845 # define perf_compat_ioctl NULL
4848 int perf_event_task_enable(void)
4850 struct perf_event_context
*ctx
;
4851 struct perf_event
*event
;
4853 mutex_lock(¤t
->perf_event_mutex
);
4854 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
) {
4855 ctx
= perf_event_ctx_lock(event
);
4856 perf_event_for_each_child(event
, _perf_event_enable
);
4857 perf_event_ctx_unlock(event
, ctx
);
4859 mutex_unlock(¤t
->perf_event_mutex
);
4864 int perf_event_task_disable(void)
4866 struct perf_event_context
*ctx
;
4867 struct perf_event
*event
;
4869 mutex_lock(¤t
->perf_event_mutex
);
4870 list_for_each_entry(event
, ¤t
->perf_event_list
, owner_entry
) {
4871 ctx
= perf_event_ctx_lock(event
);
4872 perf_event_for_each_child(event
, _perf_event_disable
);
4873 perf_event_ctx_unlock(event
, ctx
);
4875 mutex_unlock(¤t
->perf_event_mutex
);
4880 static int perf_event_index(struct perf_event
*event
)
4882 if (event
->hw
.state
& PERF_HES_STOPPED
)
4885 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
4888 return event
->pmu
->event_idx(event
);
4891 static void calc_timer_values(struct perf_event
*event
,
4898 *now
= perf_clock();
4899 ctx_time
= event
->shadow_ctx_time
+ *now
;
4900 *enabled
= ctx_time
- event
->tstamp_enabled
;
4901 *running
= ctx_time
- event
->tstamp_running
;
4904 static void perf_event_init_userpage(struct perf_event
*event
)
4906 struct perf_event_mmap_page
*userpg
;
4907 struct ring_buffer
*rb
;
4910 rb
= rcu_dereference(event
->rb
);
4914 userpg
= rb
->user_page
;
4916 /* Allow new userspace to detect that bit 0 is deprecated */
4917 userpg
->cap_bit0_is_deprecated
= 1;
4918 userpg
->size
= offsetof(struct perf_event_mmap_page
, __reserved
);
4919 userpg
->data_offset
= PAGE_SIZE
;
4920 userpg
->data_size
= perf_data_size(rb
);
4926 void __weak
arch_perf_update_userpage(
4927 struct perf_event
*event
, struct perf_event_mmap_page
*userpg
, u64 now
)
4932 * Callers need to ensure there can be no nesting of this function, otherwise
4933 * the seqlock logic goes bad. We can not serialize this because the arch
4934 * code calls this from NMI context.
4936 void perf_event_update_userpage(struct perf_event
*event
)
4938 struct perf_event_mmap_page
*userpg
;
4939 struct ring_buffer
*rb
;
4940 u64 enabled
, running
, now
;
4943 rb
= rcu_dereference(event
->rb
);
4948 * compute total_time_enabled, total_time_running
4949 * based on snapshot values taken when the event
4950 * was last scheduled in.
4952 * we cannot simply called update_context_time()
4953 * because of locking issue as we can be called in
4956 calc_timer_values(event
, &now
, &enabled
, &running
);
4958 userpg
= rb
->user_page
;
4960 * Disable preemption so as to not let the corresponding user-space
4961 * spin too long if we get preempted.
4966 userpg
->index
= perf_event_index(event
);
4967 userpg
->offset
= perf_event_count(event
);
4969 userpg
->offset
-= local64_read(&event
->hw
.prev_count
);
4971 userpg
->time_enabled
= enabled
+
4972 atomic64_read(&event
->child_total_time_enabled
);
4974 userpg
->time_running
= running
+
4975 atomic64_read(&event
->child_total_time_running
);
4977 arch_perf_update_userpage(event
, userpg
, now
);
4986 static int perf_mmap_fault(struct vm_fault
*vmf
)
4988 struct perf_event
*event
= vmf
->vma
->vm_file
->private_data
;
4989 struct ring_buffer
*rb
;
4990 int ret
= VM_FAULT_SIGBUS
;
4992 if (vmf
->flags
& FAULT_FLAG_MKWRITE
) {
4993 if (vmf
->pgoff
== 0)
4999 rb
= rcu_dereference(event
->rb
);
5003 if (vmf
->pgoff
&& (vmf
->flags
& FAULT_FLAG_WRITE
))
5006 vmf
->page
= perf_mmap_to_page(rb
, vmf
->pgoff
);
5010 get_page(vmf
->page
);
5011 vmf
->page
->mapping
= vmf
->vma
->vm_file
->f_mapping
;
5012 vmf
->page
->index
= vmf
->pgoff
;
5021 static void ring_buffer_attach(struct perf_event
*event
,
5022 struct ring_buffer
*rb
)
5024 struct ring_buffer
*old_rb
= NULL
;
5025 unsigned long flags
;
5029 * Should be impossible, we set this when removing
5030 * event->rb_entry and wait/clear when adding event->rb_entry.
5032 WARN_ON_ONCE(event
->rcu_pending
);
5035 spin_lock_irqsave(&old_rb
->event_lock
, flags
);
5036 list_del_rcu(&event
->rb_entry
);
5037 spin_unlock_irqrestore(&old_rb
->event_lock
, flags
);
5039 event
->rcu_batches
= get_state_synchronize_rcu();
5040 event
->rcu_pending
= 1;
5044 if (event
->rcu_pending
) {
5045 cond_synchronize_rcu(event
->rcu_batches
);
5046 event
->rcu_pending
= 0;
5049 spin_lock_irqsave(&rb
->event_lock
, flags
);
5050 list_add_rcu(&event
->rb_entry
, &rb
->event_list
);
5051 spin_unlock_irqrestore(&rb
->event_lock
, flags
);
5055 * Avoid racing with perf_mmap_close(AUX): stop the event
5056 * before swizzling the event::rb pointer; if it's getting
5057 * unmapped, its aux_mmap_count will be 0 and it won't
5058 * restart. See the comment in __perf_pmu_output_stop().
5060 * Data will inevitably be lost when set_output is done in
5061 * mid-air, but then again, whoever does it like this is
5062 * not in for the data anyway.
5065 perf_event_stop(event
, 0);
5067 rcu_assign_pointer(event
->rb
, rb
);
5070 ring_buffer_put(old_rb
);
5072 * Since we detached before setting the new rb, so that we
5073 * could attach the new rb, we could have missed a wakeup.
5076 wake_up_all(&event
->waitq
);
5080 static void ring_buffer_wakeup(struct perf_event
*event
)
5082 struct ring_buffer
*rb
;
5085 rb
= rcu_dereference(event
->rb
);
5087 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
)
5088 wake_up_all(&event
->waitq
);
5093 struct ring_buffer
*ring_buffer_get(struct perf_event
*event
)
5095 struct ring_buffer
*rb
;
5098 rb
= rcu_dereference(event
->rb
);
5100 if (!atomic_inc_not_zero(&rb
->refcount
))
5108 void ring_buffer_put(struct ring_buffer
*rb
)
5110 if (!atomic_dec_and_test(&rb
->refcount
))
5113 WARN_ON_ONCE(!list_empty(&rb
->event_list
));
5115 call_rcu(&rb
->rcu_head
, rb_free_rcu
);
5118 static void perf_mmap_open(struct vm_area_struct
*vma
)
5120 struct perf_event
*event
= vma
->vm_file
->private_data
;
5122 atomic_inc(&event
->mmap_count
);
5123 atomic_inc(&event
->rb
->mmap_count
);
5126 atomic_inc(&event
->rb
->aux_mmap_count
);
5128 if (event
->pmu
->event_mapped
)
5129 event
->pmu
->event_mapped(event
, vma
->vm_mm
);
5132 static void perf_pmu_output_stop(struct perf_event
*event
);
5135 * A buffer can be mmap()ed multiple times; either directly through the same
5136 * event, or through other events by use of perf_event_set_output().
5138 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5139 * the buffer here, where we still have a VM context. This means we need
5140 * to detach all events redirecting to us.
5142 static void perf_mmap_close(struct vm_area_struct
*vma
)
5144 struct perf_event
*event
= vma
->vm_file
->private_data
;
5146 struct ring_buffer
*rb
= ring_buffer_get(event
);
5147 struct user_struct
*mmap_user
= rb
->mmap_user
;
5148 int mmap_locked
= rb
->mmap_locked
;
5149 unsigned long size
= perf_data_size(rb
);
5151 if (event
->pmu
->event_unmapped
)
5152 event
->pmu
->event_unmapped(event
, vma
->vm_mm
);
5155 * rb->aux_mmap_count will always drop before rb->mmap_count and
5156 * event->mmap_count, so it is ok to use event->mmap_mutex to
5157 * serialize with perf_mmap here.
5159 if (rb_has_aux(rb
) && vma
->vm_pgoff
== rb
->aux_pgoff
&&
5160 atomic_dec_and_mutex_lock(&rb
->aux_mmap_count
, &event
->mmap_mutex
)) {
5162 * Stop all AUX events that are writing to this buffer,
5163 * so that we can free its AUX pages and corresponding PMU
5164 * data. Note that after rb::aux_mmap_count dropped to zero,
5165 * they won't start any more (see perf_aux_output_begin()).
5167 perf_pmu_output_stop(event
);
5169 /* now it's safe to free the pages */
5170 atomic_long_sub(rb
->aux_nr_pages
, &mmap_user
->locked_vm
);
5171 vma
->vm_mm
->pinned_vm
-= rb
->aux_mmap_locked
;
5173 /* this has to be the last one */
5175 WARN_ON_ONCE(atomic_read(&rb
->aux_refcount
));
5177 mutex_unlock(&event
->mmap_mutex
);
5180 atomic_dec(&rb
->mmap_count
);
5182 if (!atomic_dec_and_mutex_lock(&event
->mmap_count
, &event
->mmap_mutex
))
5185 ring_buffer_attach(event
, NULL
);
5186 mutex_unlock(&event
->mmap_mutex
);
5188 /* If there's still other mmap()s of this buffer, we're done. */
5189 if (atomic_read(&rb
->mmap_count
))
5193 * No other mmap()s, detach from all other events that might redirect
5194 * into the now unreachable buffer. Somewhat complicated by the
5195 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5199 list_for_each_entry_rcu(event
, &rb
->event_list
, rb_entry
) {
5200 if (!atomic_long_inc_not_zero(&event
->refcount
)) {
5202 * This event is en-route to free_event() which will
5203 * detach it and remove it from the list.
5209 mutex_lock(&event
->mmap_mutex
);
5211 * Check we didn't race with perf_event_set_output() which can
5212 * swizzle the rb from under us while we were waiting to
5213 * acquire mmap_mutex.
5215 * If we find a different rb; ignore this event, a next
5216 * iteration will no longer find it on the list. We have to
5217 * still restart the iteration to make sure we're not now
5218 * iterating the wrong list.
5220 if (event
->rb
== rb
)
5221 ring_buffer_attach(event
, NULL
);
5223 mutex_unlock(&event
->mmap_mutex
);
5227 * Restart the iteration; either we're on the wrong list or
5228 * destroyed its integrity by doing a deletion.
5235 * It could be there's still a few 0-ref events on the list; they'll
5236 * get cleaned up by free_event() -- they'll also still have their
5237 * ref on the rb and will free it whenever they are done with it.
5239 * Aside from that, this buffer is 'fully' detached and unmapped,
5240 * undo the VM accounting.
5243 atomic_long_sub((size
>> PAGE_SHIFT
) + 1, &mmap_user
->locked_vm
);
5244 vma
->vm_mm
->pinned_vm
-= mmap_locked
;
5245 free_uid(mmap_user
);
5248 ring_buffer_put(rb
); /* could be last */
5251 static const struct vm_operations_struct perf_mmap_vmops
= {
5252 .open
= perf_mmap_open
,
5253 .close
= perf_mmap_close
, /* non mergable */
5254 .fault
= perf_mmap_fault
,
5255 .page_mkwrite
= perf_mmap_fault
,
5258 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
5260 struct perf_event
*event
= file
->private_data
;
5261 unsigned long user_locked
, user_lock_limit
;
5262 struct user_struct
*user
= current_user();
5263 unsigned long locked
, lock_limit
;
5264 struct ring_buffer
*rb
= NULL
;
5265 unsigned long vma_size
;
5266 unsigned long nr_pages
;
5267 long user_extra
= 0, extra
= 0;
5268 int ret
= 0, flags
= 0;
5271 * Don't allow mmap() of inherited per-task counters. This would
5272 * create a performance issue due to all children writing to the
5275 if (event
->cpu
== -1 && event
->attr
.inherit
)
5278 if (!(vma
->vm_flags
& VM_SHARED
))
5281 vma_size
= vma
->vm_end
- vma
->vm_start
;
5283 if (vma
->vm_pgoff
== 0) {
5284 nr_pages
= (vma_size
/ PAGE_SIZE
) - 1;
5287 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5288 * mapped, all subsequent mappings should have the same size
5289 * and offset. Must be above the normal perf buffer.
5291 u64 aux_offset
, aux_size
;
5296 nr_pages
= vma_size
/ PAGE_SIZE
;
5298 mutex_lock(&event
->mmap_mutex
);
5305 aux_offset
= ACCESS_ONCE(rb
->user_page
->aux_offset
);
5306 aux_size
= ACCESS_ONCE(rb
->user_page
->aux_size
);
5308 if (aux_offset
< perf_data_size(rb
) + PAGE_SIZE
)
5311 if (aux_offset
!= vma
->vm_pgoff
<< PAGE_SHIFT
)
5314 /* already mapped with a different offset */
5315 if (rb_has_aux(rb
) && rb
->aux_pgoff
!= vma
->vm_pgoff
)
5318 if (aux_size
!= vma_size
|| aux_size
!= nr_pages
* PAGE_SIZE
)
5321 /* already mapped with a different size */
5322 if (rb_has_aux(rb
) && rb
->aux_nr_pages
!= nr_pages
)
5325 if (!is_power_of_2(nr_pages
))
5328 if (!atomic_inc_not_zero(&rb
->mmap_count
))
5331 if (rb_has_aux(rb
)) {
5332 atomic_inc(&rb
->aux_mmap_count
);
5337 atomic_set(&rb
->aux_mmap_count
, 1);
5338 user_extra
= nr_pages
;
5344 * If we have rb pages ensure they're a power-of-two number, so we
5345 * can do bitmasks instead of modulo.
5347 if (nr_pages
!= 0 && !is_power_of_2(nr_pages
))
5350 if (vma_size
!= PAGE_SIZE
* (1 + nr_pages
))
5353 WARN_ON_ONCE(event
->ctx
->parent_ctx
);
5355 mutex_lock(&event
->mmap_mutex
);
5357 if (event
->rb
->nr_pages
!= nr_pages
) {
5362 if (!atomic_inc_not_zero(&event
->rb
->mmap_count
)) {
5364 * Raced against perf_mmap_close() through
5365 * perf_event_set_output(). Try again, hope for better
5368 mutex_unlock(&event
->mmap_mutex
);
5375 user_extra
= nr_pages
+ 1;
5378 user_lock_limit
= sysctl_perf_event_mlock
>> (PAGE_SHIFT
- 10);
5381 * Increase the limit linearly with more CPUs:
5383 user_lock_limit
*= num_online_cpus();
5385 user_locked
= atomic_long_read(&user
->locked_vm
) + user_extra
;
5387 if (user_locked
> user_lock_limit
)
5388 extra
= user_locked
- user_lock_limit
;
5390 lock_limit
= rlimit(RLIMIT_MEMLOCK
);
5391 lock_limit
>>= PAGE_SHIFT
;
5392 locked
= vma
->vm_mm
->pinned_vm
+ extra
;
5394 if ((locked
> lock_limit
) && perf_paranoid_tracepoint_raw() &&
5395 !capable(CAP_IPC_LOCK
)) {
5400 WARN_ON(!rb
&& event
->rb
);
5402 if (vma
->vm_flags
& VM_WRITE
)
5403 flags
|= RING_BUFFER_WRITABLE
;
5406 rb
= rb_alloc(nr_pages
,
5407 event
->attr
.watermark
? event
->attr
.wakeup_watermark
: 0,
5415 atomic_set(&rb
->mmap_count
, 1);
5416 rb
->mmap_user
= get_current_user();
5417 rb
->mmap_locked
= extra
;
5419 ring_buffer_attach(event
, rb
);
5421 perf_event_init_userpage(event
);
5422 perf_event_update_userpage(event
);
5424 ret
= rb_alloc_aux(rb
, event
, vma
->vm_pgoff
, nr_pages
,
5425 event
->attr
.aux_watermark
, flags
);
5427 rb
->aux_mmap_locked
= extra
;
5432 atomic_long_add(user_extra
, &user
->locked_vm
);
5433 vma
->vm_mm
->pinned_vm
+= extra
;
5435 atomic_inc(&event
->mmap_count
);
5437 atomic_dec(&rb
->mmap_count
);
5440 mutex_unlock(&event
->mmap_mutex
);
5443 * Since pinned accounting is per vm we cannot allow fork() to copy our
5446 vma
->vm_flags
|= VM_DONTCOPY
| VM_DONTEXPAND
| VM_DONTDUMP
;
5447 vma
->vm_ops
= &perf_mmap_vmops
;
5449 if (event
->pmu
->event_mapped
)
5450 event
->pmu
->event_mapped(event
, vma
->vm_mm
);
5455 static int perf_fasync(int fd
, struct file
*filp
, int on
)
5457 struct inode
*inode
= file_inode(filp
);
5458 struct perf_event
*event
= filp
->private_data
;
5462 retval
= fasync_helper(fd
, filp
, on
, &event
->fasync
);
5463 inode_unlock(inode
);
5471 static const struct file_operations perf_fops
= {
5472 .llseek
= no_llseek
,
5473 .release
= perf_release
,
5476 .unlocked_ioctl
= perf_ioctl
,
5477 .compat_ioctl
= perf_compat_ioctl
,
5479 .fasync
= perf_fasync
,
5485 * If there's data, ensure we set the poll() state and publish everything
5486 * to user-space before waking everybody up.
5489 static inline struct fasync_struct
**perf_event_fasync(struct perf_event
*event
)
5491 /* only the parent has fasync state */
5493 event
= event
->parent
;
5494 return &event
->fasync
;
5497 void perf_event_wakeup(struct perf_event
*event
)
5499 ring_buffer_wakeup(event
);
5501 if (event
->pending_kill
) {
5502 kill_fasync(perf_event_fasync(event
), SIGIO
, event
->pending_kill
);
5503 event
->pending_kill
= 0;
5507 static void perf_pending_event(struct irq_work
*entry
)
5509 struct perf_event
*event
= container_of(entry
,
5510 struct perf_event
, pending
);
5513 rctx
= perf_swevent_get_recursion_context();
5515 * If we 'fail' here, that's OK, it means recursion is already disabled
5516 * and we won't recurse 'further'.
5519 if (event
->pending_disable
) {
5520 event
->pending_disable
= 0;
5521 perf_event_disable_local(event
);
5524 if (event
->pending_wakeup
) {
5525 event
->pending_wakeup
= 0;
5526 perf_event_wakeup(event
);
5530 perf_swevent_put_recursion_context(rctx
);
5534 * We assume there is only KVM supporting the callbacks.
5535 * Later on, we might change it to a list if there is
5536 * another virtualization implementation supporting the callbacks.
5538 struct perf_guest_info_callbacks
*perf_guest_cbs
;
5540 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
5542 perf_guest_cbs
= cbs
;
5545 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks
);
5547 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks
*cbs
)
5549 perf_guest_cbs
= NULL
;
5552 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks
);
5555 perf_output_sample_regs(struct perf_output_handle
*handle
,
5556 struct pt_regs
*regs
, u64 mask
)
5559 DECLARE_BITMAP(_mask
, 64);
5561 bitmap_from_u64(_mask
, mask
);
5562 for_each_set_bit(bit
, _mask
, sizeof(mask
) * BITS_PER_BYTE
) {
5565 val
= perf_reg_value(regs
, bit
);
5566 perf_output_put(handle
, val
);
5570 static void perf_sample_regs_user(struct perf_regs
*regs_user
,
5571 struct pt_regs
*regs
,
5572 struct pt_regs
*regs_user_copy
)
5574 if (user_mode(regs
)) {
5575 regs_user
->abi
= perf_reg_abi(current
);
5576 regs_user
->regs
= regs
;
5577 } else if (current
->mm
) {
5578 perf_get_regs_user(regs_user
, regs
, regs_user_copy
);
5580 regs_user
->abi
= PERF_SAMPLE_REGS_ABI_NONE
;
5581 regs_user
->regs
= NULL
;
5585 static void perf_sample_regs_intr(struct perf_regs
*regs_intr
,
5586 struct pt_regs
*regs
)
5588 regs_intr
->regs
= regs
;
5589 regs_intr
->abi
= perf_reg_abi(current
);
5594 * Get remaining task size from user stack pointer.
5596 * It'd be better to take stack vma map and limit this more
5597 * precisly, but there's no way to get it safely under interrupt,
5598 * so using TASK_SIZE as limit.
5600 static u64
perf_ustack_task_size(struct pt_regs
*regs
)
5602 unsigned long addr
= perf_user_stack_pointer(regs
);
5604 if (!addr
|| addr
>= TASK_SIZE
)
5607 return TASK_SIZE
- addr
;
5611 perf_sample_ustack_size(u16 stack_size
, u16 header_size
,
5612 struct pt_regs
*regs
)
5616 /* No regs, no stack pointer, no dump. */
5621 * Check if we fit in with the requested stack size into the:
5623 * If we don't, we limit the size to the TASK_SIZE.
5625 * - remaining sample size
5626 * If we don't, we customize the stack size to
5627 * fit in to the remaining sample size.
5630 task_size
= min((u64
) USHRT_MAX
, perf_ustack_task_size(regs
));
5631 stack_size
= min(stack_size
, (u16
) task_size
);
5633 /* Current header size plus static size and dynamic size. */
5634 header_size
+= 2 * sizeof(u64
);
5636 /* Do we fit in with the current stack dump size? */
5637 if ((u16
) (header_size
+ stack_size
) < header_size
) {
5639 * If we overflow the maximum size for the sample,
5640 * we customize the stack dump size to fit in.
5642 stack_size
= USHRT_MAX
- header_size
- sizeof(u64
);
5643 stack_size
= round_up(stack_size
, sizeof(u64
));
5650 perf_output_sample_ustack(struct perf_output_handle
*handle
, u64 dump_size
,
5651 struct pt_regs
*regs
)
5653 /* Case of a kernel thread, nothing to dump */
5656 perf_output_put(handle
, size
);
5665 * - the size requested by user or the best one we can fit
5666 * in to the sample max size
5668 * - user stack dump data
5670 * - the actual dumped size
5674 perf_output_put(handle
, dump_size
);
5677 sp
= perf_user_stack_pointer(regs
);
5678 rem
= __output_copy_user(handle
, (void *) sp
, dump_size
);
5679 dyn_size
= dump_size
- rem
;
5681 perf_output_skip(handle
, rem
);
5684 perf_output_put(handle
, dyn_size
);
5688 static void __perf_event_header__init_id(struct perf_event_header
*header
,
5689 struct perf_sample_data
*data
,
5690 struct perf_event
*event
)
5692 u64 sample_type
= event
->attr
.sample_type
;
5694 data
->type
= sample_type
;
5695 header
->size
+= event
->id_header_size
;
5697 if (sample_type
& PERF_SAMPLE_TID
) {
5698 /* namespace issues */
5699 data
->tid_entry
.pid
= perf_event_pid(event
, current
);
5700 data
->tid_entry
.tid
= perf_event_tid(event
, current
);
5703 if (sample_type
& PERF_SAMPLE_TIME
)
5704 data
->time
= perf_event_clock(event
);
5706 if (sample_type
& (PERF_SAMPLE_ID
| PERF_SAMPLE_IDENTIFIER
))
5707 data
->id
= primary_event_id(event
);
5709 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
5710 data
->stream_id
= event
->id
;
5712 if (sample_type
& PERF_SAMPLE_CPU
) {
5713 data
->cpu_entry
.cpu
= raw_smp_processor_id();
5714 data
->cpu_entry
.reserved
= 0;
5718 void perf_event_header__init_id(struct perf_event_header
*header
,
5719 struct perf_sample_data
*data
,
5720 struct perf_event
*event
)
5722 if (event
->attr
.sample_id_all
)
5723 __perf_event_header__init_id(header
, data
, event
);
5726 static void __perf_event__output_id_sample(struct perf_output_handle
*handle
,
5727 struct perf_sample_data
*data
)
5729 u64 sample_type
= data
->type
;
5731 if (sample_type
& PERF_SAMPLE_TID
)
5732 perf_output_put(handle
, data
->tid_entry
);
5734 if (sample_type
& PERF_SAMPLE_TIME
)
5735 perf_output_put(handle
, data
->time
);
5737 if (sample_type
& PERF_SAMPLE_ID
)
5738 perf_output_put(handle
, data
->id
);
5740 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
5741 perf_output_put(handle
, data
->stream_id
);
5743 if (sample_type
& PERF_SAMPLE_CPU
)
5744 perf_output_put(handle
, data
->cpu_entry
);
5746 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
5747 perf_output_put(handle
, data
->id
);
5750 void perf_event__output_id_sample(struct perf_event
*event
,
5751 struct perf_output_handle
*handle
,
5752 struct perf_sample_data
*sample
)
5754 if (event
->attr
.sample_id_all
)
5755 __perf_event__output_id_sample(handle
, sample
);
5758 static void perf_output_read_one(struct perf_output_handle
*handle
,
5759 struct perf_event
*event
,
5760 u64 enabled
, u64 running
)
5762 u64 read_format
= event
->attr
.read_format
;
5766 values
[n
++] = perf_event_count(event
);
5767 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
) {
5768 values
[n
++] = enabled
+
5769 atomic64_read(&event
->child_total_time_enabled
);
5771 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
) {
5772 values
[n
++] = running
+
5773 atomic64_read(&event
->child_total_time_running
);
5775 if (read_format
& PERF_FORMAT_ID
)
5776 values
[n
++] = primary_event_id(event
);
5778 __output_copy(handle
, values
, n
* sizeof(u64
));
5781 static void perf_output_read_group(struct perf_output_handle
*handle
,
5782 struct perf_event
*event
,
5783 u64 enabled
, u64 running
)
5785 struct perf_event
*leader
= event
->group_leader
, *sub
;
5786 u64 read_format
= event
->attr
.read_format
;
5790 values
[n
++] = 1 + leader
->nr_siblings
;
5792 if (read_format
& PERF_FORMAT_TOTAL_TIME_ENABLED
)
5793 values
[n
++] = enabled
;
5795 if (read_format
& PERF_FORMAT_TOTAL_TIME_RUNNING
)
5796 values
[n
++] = running
;
5798 if (leader
!= event
)
5799 leader
->pmu
->read(leader
);
5801 values
[n
++] = perf_event_count(leader
);
5802 if (read_format
& PERF_FORMAT_ID
)
5803 values
[n
++] = primary_event_id(leader
);
5805 __output_copy(handle
, values
, n
* sizeof(u64
));
5807 list_for_each_entry(sub
, &leader
->sibling_list
, group_entry
) {
5810 if ((sub
!= event
) &&
5811 (sub
->state
== PERF_EVENT_STATE_ACTIVE
))
5812 sub
->pmu
->read(sub
);
5814 values
[n
++] = perf_event_count(sub
);
5815 if (read_format
& PERF_FORMAT_ID
)
5816 values
[n
++] = primary_event_id(sub
);
5818 __output_copy(handle
, values
, n
* sizeof(u64
));
5822 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5823 PERF_FORMAT_TOTAL_TIME_RUNNING)
5826 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
5828 * The problem is that its both hard and excessively expensive to iterate the
5829 * child list, not to mention that its impossible to IPI the children running
5830 * on another CPU, from interrupt/NMI context.
5832 static void perf_output_read(struct perf_output_handle
*handle
,
5833 struct perf_event
*event
)
5835 u64 enabled
= 0, running
= 0, now
;
5836 u64 read_format
= event
->attr
.read_format
;
5839 * compute total_time_enabled, total_time_running
5840 * based on snapshot values taken when the event
5841 * was last scheduled in.
5843 * we cannot simply called update_context_time()
5844 * because of locking issue as we are called in
5847 if (read_format
& PERF_FORMAT_TOTAL_TIMES
)
5848 calc_timer_values(event
, &now
, &enabled
, &running
);
5850 if (event
->attr
.read_format
& PERF_FORMAT_GROUP
)
5851 perf_output_read_group(handle
, event
, enabled
, running
);
5853 perf_output_read_one(handle
, event
, enabled
, running
);
5856 void perf_output_sample(struct perf_output_handle
*handle
,
5857 struct perf_event_header
*header
,
5858 struct perf_sample_data
*data
,
5859 struct perf_event
*event
)
5861 u64 sample_type
= data
->type
;
5863 perf_output_put(handle
, *header
);
5865 if (sample_type
& PERF_SAMPLE_IDENTIFIER
)
5866 perf_output_put(handle
, data
->id
);
5868 if (sample_type
& PERF_SAMPLE_IP
)
5869 perf_output_put(handle
, data
->ip
);
5871 if (sample_type
& PERF_SAMPLE_TID
)
5872 perf_output_put(handle
, data
->tid_entry
);
5874 if (sample_type
& PERF_SAMPLE_TIME
)
5875 perf_output_put(handle
, data
->time
);
5877 if (sample_type
& PERF_SAMPLE_ADDR
)
5878 perf_output_put(handle
, data
->addr
);
5880 if (sample_type
& PERF_SAMPLE_ID
)
5881 perf_output_put(handle
, data
->id
);
5883 if (sample_type
& PERF_SAMPLE_STREAM_ID
)
5884 perf_output_put(handle
, data
->stream_id
);
5886 if (sample_type
& PERF_SAMPLE_CPU
)
5887 perf_output_put(handle
, data
->cpu_entry
);
5889 if (sample_type
& PERF_SAMPLE_PERIOD
)
5890 perf_output_put(handle
, data
->period
);
5892 if (sample_type
& PERF_SAMPLE_READ
)
5893 perf_output_read(handle
, event
);
5895 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
5896 if (data
->callchain
) {
5899 if (data
->callchain
)
5900 size
+= data
->callchain
->nr
;
5902 size
*= sizeof(u64
);
5904 __output_copy(handle
, data
->callchain
, size
);
5907 perf_output_put(handle
, nr
);
5911 if (sample_type
& PERF_SAMPLE_RAW
) {
5912 struct perf_raw_record
*raw
= data
->raw
;
5915 struct perf_raw_frag
*frag
= &raw
->frag
;
5917 perf_output_put(handle
, raw
->size
);
5920 __output_custom(handle
, frag
->copy
,
5921 frag
->data
, frag
->size
);
5923 __output_copy(handle
, frag
->data
,
5926 if (perf_raw_frag_last(frag
))
5931 __output_skip(handle
, NULL
, frag
->pad
);
5937 .size
= sizeof(u32
),
5940 perf_output_put(handle
, raw
);
5944 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
5945 if (data
->br_stack
) {
5948 size
= data
->br_stack
->nr
5949 * sizeof(struct perf_branch_entry
);
5951 perf_output_put(handle
, data
->br_stack
->nr
);
5952 perf_output_copy(handle
, data
->br_stack
->entries
, size
);
5955 * we always store at least the value of nr
5958 perf_output_put(handle
, nr
);
5962 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
5963 u64 abi
= data
->regs_user
.abi
;
5966 * If there are no regs to dump, notice it through
5967 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5969 perf_output_put(handle
, abi
);
5972 u64 mask
= event
->attr
.sample_regs_user
;
5973 perf_output_sample_regs(handle
,
5974 data
->regs_user
.regs
,
5979 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
5980 perf_output_sample_ustack(handle
,
5981 data
->stack_user_size
,
5982 data
->regs_user
.regs
);
5985 if (sample_type
& PERF_SAMPLE_WEIGHT
)
5986 perf_output_put(handle
, data
->weight
);
5988 if (sample_type
& PERF_SAMPLE_DATA_SRC
)
5989 perf_output_put(handle
, data
->data_src
.val
);
5991 if (sample_type
& PERF_SAMPLE_TRANSACTION
)
5992 perf_output_put(handle
, data
->txn
);
5994 if (sample_type
& PERF_SAMPLE_REGS_INTR
) {
5995 u64 abi
= data
->regs_intr
.abi
;
5997 * If there are no regs to dump, notice it through
5998 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6000 perf_output_put(handle
, abi
);
6003 u64 mask
= event
->attr
.sample_regs_intr
;
6005 perf_output_sample_regs(handle
,
6006 data
->regs_intr
.regs
,
6011 if (sample_type
& PERF_SAMPLE_PHYS_ADDR
)
6012 perf_output_put(handle
, data
->phys_addr
);
6014 if (!event
->attr
.watermark
) {
6015 int wakeup_events
= event
->attr
.wakeup_events
;
6017 if (wakeup_events
) {
6018 struct ring_buffer
*rb
= handle
->rb
;
6019 int events
= local_inc_return(&rb
->events
);
6021 if (events
>= wakeup_events
) {
6022 local_sub(wakeup_events
, &rb
->events
);
6023 local_inc(&rb
->wakeup
);
6029 static u64
perf_virt_to_phys(u64 virt
)
6032 struct page
*p
= NULL
;
6037 if (virt
>= TASK_SIZE
) {
6038 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6039 if (virt_addr_valid((void *)(uintptr_t)virt
) &&
6040 !(virt
>= VMALLOC_START
&& virt
< VMALLOC_END
))
6041 phys_addr
= (u64
)virt_to_phys((void *)(uintptr_t)virt
);
6044 * Walking the pages tables for user address.
6045 * Interrupts are disabled, so it prevents any tear down
6046 * of the page tables.
6047 * Try IRQ-safe __get_user_pages_fast first.
6048 * If failed, leave phys_addr as 0.
6050 if ((current
->mm
!= NULL
) &&
6051 (__get_user_pages_fast(virt
, 1, 0, &p
) == 1))
6052 phys_addr
= page_to_phys(p
) + virt
% PAGE_SIZE
;
6061 void perf_prepare_sample(struct perf_event_header
*header
,
6062 struct perf_sample_data
*data
,
6063 struct perf_event
*event
,
6064 struct pt_regs
*regs
)
6066 u64 sample_type
= event
->attr
.sample_type
;
6068 header
->type
= PERF_RECORD_SAMPLE
;
6069 header
->size
= sizeof(*header
) + event
->header_size
;
6072 header
->misc
|= perf_misc_flags(regs
);
6074 __perf_event_header__init_id(header
, data
, event
);
6076 if (sample_type
& PERF_SAMPLE_IP
)
6077 data
->ip
= perf_instruction_pointer(regs
);
6079 if (sample_type
& PERF_SAMPLE_CALLCHAIN
) {
6082 data
->callchain
= perf_callchain(event
, regs
);
6084 if (data
->callchain
)
6085 size
+= data
->callchain
->nr
;
6087 header
->size
+= size
* sizeof(u64
);
6090 if (sample_type
& PERF_SAMPLE_RAW
) {
6091 struct perf_raw_record
*raw
= data
->raw
;
6095 struct perf_raw_frag
*frag
= &raw
->frag
;
6100 if (perf_raw_frag_last(frag
))
6105 size
= round_up(sum
+ sizeof(u32
), sizeof(u64
));
6106 raw
->size
= size
- sizeof(u32
);
6107 frag
->pad
= raw
->size
- sum
;
6112 header
->size
+= size
;
6115 if (sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
6116 int size
= sizeof(u64
); /* nr */
6117 if (data
->br_stack
) {
6118 size
+= data
->br_stack
->nr
6119 * sizeof(struct perf_branch_entry
);
6121 header
->size
+= size
;
6124 if (sample_type
& (PERF_SAMPLE_REGS_USER
| PERF_SAMPLE_STACK_USER
))
6125 perf_sample_regs_user(&data
->regs_user
, regs
,
6126 &data
->regs_user_copy
);
6128 if (sample_type
& PERF_SAMPLE_REGS_USER
) {
6129 /* regs dump ABI info */
6130 int size
= sizeof(u64
);
6132 if (data
->regs_user
.regs
) {
6133 u64 mask
= event
->attr
.sample_regs_user
;
6134 size
+= hweight64(mask
) * sizeof(u64
);
6137 header
->size
+= size
;
6140 if (sample_type
& PERF_SAMPLE_STACK_USER
) {
6142 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6143 * processed as the last one or have additional check added
6144 * in case new sample type is added, because we could eat
6145 * up the rest of the sample size.
6147 u16 stack_size
= event
->attr
.sample_stack_user
;
6148 u16 size
= sizeof(u64
);
6150 stack_size
= perf_sample_ustack_size(stack_size
, header
->size
,
6151 data
->regs_user
.regs
);
6154 * If there is something to dump, add space for the dump
6155 * itself and for the field that tells the dynamic size,
6156 * which is how many have been actually dumped.
6159 size
+= sizeof(u64
) + stack_size
;
6161 data
->stack_user_size
= stack_size
;
6162 header
->size
+= size
;
6165 if (sample_type
& PERF_SAMPLE_REGS_INTR
) {
6166 /* regs dump ABI info */
6167 int size
= sizeof(u64
);
6169 perf_sample_regs_intr(&data
->regs_intr
, regs
);
6171 if (data
->regs_intr
.regs
) {
6172 u64 mask
= event
->attr
.sample_regs_intr
;
6174 size
+= hweight64(mask
) * sizeof(u64
);
6177 header
->size
+= size
;
6180 if (sample_type
& PERF_SAMPLE_PHYS_ADDR
)
6181 data
->phys_addr
= perf_virt_to_phys(data
->addr
);
6184 static void __always_inline
6185 __perf_event_output(struct perf_event
*event
,
6186 struct perf_sample_data
*data
,
6187 struct pt_regs
*regs
,
6188 int (*output_begin
)(struct perf_output_handle
*,
6189 struct perf_event
*,
6192 struct perf_output_handle handle
;
6193 struct perf_event_header header
;
6195 /* protect the callchain buffers */
6198 perf_prepare_sample(&header
, data
, event
, regs
);
6200 if (output_begin(&handle
, event
, header
.size
))
6203 perf_output_sample(&handle
, &header
, data
, event
);
6205 perf_output_end(&handle
);
6212 perf_event_output_forward(struct perf_event
*event
,
6213 struct perf_sample_data
*data
,
6214 struct pt_regs
*regs
)
6216 __perf_event_output(event
, data
, regs
, perf_output_begin_forward
);
6220 perf_event_output_backward(struct perf_event
*event
,
6221 struct perf_sample_data
*data
,
6222 struct pt_regs
*regs
)
6224 __perf_event_output(event
, data
, regs
, perf_output_begin_backward
);
6228 perf_event_output(struct perf_event
*event
,
6229 struct perf_sample_data
*data
,
6230 struct pt_regs
*regs
)
6232 __perf_event_output(event
, data
, regs
, perf_output_begin
);
6239 struct perf_read_event
{
6240 struct perf_event_header header
;
6247 perf_event_read_event(struct perf_event
*event
,
6248 struct task_struct
*task
)
6250 struct perf_output_handle handle
;
6251 struct perf_sample_data sample
;
6252 struct perf_read_event read_event
= {
6254 .type
= PERF_RECORD_READ
,
6256 .size
= sizeof(read_event
) + event
->read_size
,
6258 .pid
= perf_event_pid(event
, task
),
6259 .tid
= perf_event_tid(event
, task
),
6263 perf_event_header__init_id(&read_event
.header
, &sample
, event
);
6264 ret
= perf_output_begin(&handle
, event
, read_event
.header
.size
);
6268 perf_output_put(&handle
, read_event
);
6269 perf_output_read(&handle
, event
);
6270 perf_event__output_id_sample(event
, &handle
, &sample
);
6272 perf_output_end(&handle
);
6275 typedef void (perf_iterate_f
)(struct perf_event
*event
, void *data
);
6278 perf_iterate_ctx(struct perf_event_context
*ctx
,
6279 perf_iterate_f output
,
6280 void *data
, bool all
)
6282 struct perf_event
*event
;
6284 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
6286 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
6288 if (!event_filter_match(event
))
6292 output(event
, data
);
6296 static void perf_iterate_sb_cpu(perf_iterate_f output
, void *data
)
6298 struct pmu_event_list
*pel
= this_cpu_ptr(&pmu_sb_events
);
6299 struct perf_event
*event
;
6301 list_for_each_entry_rcu(event
, &pel
->list
, sb_list
) {
6303 * Skip events that are not fully formed yet; ensure that
6304 * if we observe event->ctx, both event and ctx will be
6305 * complete enough. See perf_install_in_context().
6307 if (!smp_load_acquire(&event
->ctx
))
6310 if (event
->state
< PERF_EVENT_STATE_INACTIVE
)
6312 if (!event_filter_match(event
))
6314 output(event
, data
);
6319 * Iterate all events that need to receive side-band events.
6321 * For new callers; ensure that account_pmu_sb_event() includes
6322 * your event, otherwise it might not get delivered.
6325 perf_iterate_sb(perf_iterate_f output
, void *data
,
6326 struct perf_event_context
*task_ctx
)
6328 struct perf_event_context
*ctx
;
6335 * If we have task_ctx != NULL we only notify the task context itself.
6336 * The task_ctx is set only for EXIT events before releasing task
6340 perf_iterate_ctx(task_ctx
, output
, data
, false);
6344 perf_iterate_sb_cpu(output
, data
);
6346 for_each_task_context_nr(ctxn
) {
6347 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
6349 perf_iterate_ctx(ctx
, output
, data
, false);
6357 * Clear all file-based filters at exec, they'll have to be
6358 * re-instated when/if these objects are mmapped again.
6360 static void perf_event_addr_filters_exec(struct perf_event
*event
, void *data
)
6362 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
6363 struct perf_addr_filter
*filter
;
6364 unsigned int restart
= 0, count
= 0;
6365 unsigned long flags
;
6367 if (!has_addr_filter(event
))
6370 raw_spin_lock_irqsave(&ifh
->lock
, flags
);
6371 list_for_each_entry(filter
, &ifh
->list
, entry
) {
6372 if (filter
->inode
) {
6373 event
->addr_filters_offs
[count
] = 0;
6381 event
->addr_filters_gen
++;
6382 raw_spin_unlock_irqrestore(&ifh
->lock
, flags
);
6385 perf_event_stop(event
, 1);
6388 void perf_event_exec(void)
6390 struct perf_event_context
*ctx
;
6394 for_each_task_context_nr(ctxn
) {
6395 ctx
= current
->perf_event_ctxp
[ctxn
];
6399 perf_event_enable_on_exec(ctxn
);
6401 perf_iterate_ctx(ctx
, perf_event_addr_filters_exec
, NULL
,
6407 struct remote_output
{
6408 struct ring_buffer
*rb
;
6412 static void __perf_event_output_stop(struct perf_event
*event
, void *data
)
6414 struct perf_event
*parent
= event
->parent
;
6415 struct remote_output
*ro
= data
;
6416 struct ring_buffer
*rb
= ro
->rb
;
6417 struct stop_event_data sd
= {
6421 if (!has_aux(event
))
6428 * In case of inheritance, it will be the parent that links to the
6429 * ring-buffer, but it will be the child that's actually using it.
6431 * We are using event::rb to determine if the event should be stopped,
6432 * however this may race with ring_buffer_attach() (through set_output),
6433 * which will make us skip the event that actually needs to be stopped.
6434 * So ring_buffer_attach() has to stop an aux event before re-assigning
6437 if (rcu_dereference(parent
->rb
) == rb
)
6438 ro
->err
= __perf_event_stop(&sd
);
6441 static int __perf_pmu_output_stop(void *info
)
6443 struct perf_event
*event
= info
;
6444 struct pmu
*pmu
= event
->pmu
;
6445 struct perf_cpu_context
*cpuctx
= this_cpu_ptr(pmu
->pmu_cpu_context
);
6446 struct remote_output ro
= {
6451 perf_iterate_ctx(&cpuctx
->ctx
, __perf_event_output_stop
, &ro
, false);
6452 if (cpuctx
->task_ctx
)
6453 perf_iterate_ctx(cpuctx
->task_ctx
, __perf_event_output_stop
,
6460 static void perf_pmu_output_stop(struct perf_event
*event
)
6462 struct perf_event
*iter
;
6467 list_for_each_entry_rcu(iter
, &event
->rb
->event_list
, rb_entry
) {
6469 * For per-CPU events, we need to make sure that neither they
6470 * nor their children are running; for cpu==-1 events it's
6471 * sufficient to stop the event itself if it's active, since
6472 * it can't have children.
6476 cpu
= READ_ONCE(iter
->oncpu
);
6481 err
= cpu_function_call(cpu
, __perf_pmu_output_stop
, event
);
6482 if (err
== -EAGAIN
) {
6491 * task tracking -- fork/exit
6493 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6496 struct perf_task_event
{
6497 struct task_struct
*task
;
6498 struct perf_event_context
*task_ctx
;
6501 struct perf_event_header header
;
6511 static int perf_event_task_match(struct perf_event
*event
)
6513 return event
->attr
.comm
|| event
->attr
.mmap
||
6514 event
->attr
.mmap2
|| event
->attr
.mmap_data
||
6518 static void perf_event_task_output(struct perf_event
*event
,
6521 struct perf_task_event
*task_event
= data
;
6522 struct perf_output_handle handle
;
6523 struct perf_sample_data sample
;
6524 struct task_struct
*task
= task_event
->task
;
6525 int ret
, size
= task_event
->event_id
.header
.size
;
6527 if (!perf_event_task_match(event
))
6530 perf_event_header__init_id(&task_event
->event_id
.header
, &sample
, event
);
6532 ret
= perf_output_begin(&handle
, event
,
6533 task_event
->event_id
.header
.size
);
6537 task_event
->event_id
.pid
= perf_event_pid(event
, task
);
6538 task_event
->event_id
.ppid
= perf_event_pid(event
, current
);
6540 task_event
->event_id
.tid
= perf_event_tid(event
, task
);
6541 task_event
->event_id
.ptid
= perf_event_tid(event
, current
);
6543 task_event
->event_id
.time
= perf_event_clock(event
);
6545 perf_output_put(&handle
, task_event
->event_id
);
6547 perf_event__output_id_sample(event
, &handle
, &sample
);
6549 perf_output_end(&handle
);
6551 task_event
->event_id
.header
.size
= size
;
6554 static void perf_event_task(struct task_struct
*task
,
6555 struct perf_event_context
*task_ctx
,
6558 struct perf_task_event task_event
;
6560 if (!atomic_read(&nr_comm_events
) &&
6561 !atomic_read(&nr_mmap_events
) &&
6562 !atomic_read(&nr_task_events
))
6565 task_event
= (struct perf_task_event
){
6567 .task_ctx
= task_ctx
,
6570 .type
= new ? PERF_RECORD_FORK
: PERF_RECORD_EXIT
,
6572 .size
= sizeof(task_event
.event_id
),
6582 perf_iterate_sb(perf_event_task_output
,
6587 void perf_event_fork(struct task_struct
*task
)
6589 perf_event_task(task
, NULL
, 1);
6590 perf_event_namespaces(task
);
6597 struct perf_comm_event
{
6598 struct task_struct
*task
;
6603 struct perf_event_header header
;
6610 static int perf_event_comm_match(struct perf_event
*event
)
6612 return event
->attr
.comm
;
6615 static void perf_event_comm_output(struct perf_event
*event
,
6618 struct perf_comm_event
*comm_event
= data
;
6619 struct perf_output_handle handle
;
6620 struct perf_sample_data sample
;
6621 int size
= comm_event
->event_id
.header
.size
;
6624 if (!perf_event_comm_match(event
))
6627 perf_event_header__init_id(&comm_event
->event_id
.header
, &sample
, event
);
6628 ret
= perf_output_begin(&handle
, event
,
6629 comm_event
->event_id
.header
.size
);
6634 comm_event
->event_id
.pid
= perf_event_pid(event
, comm_event
->task
);
6635 comm_event
->event_id
.tid
= perf_event_tid(event
, comm_event
->task
);
6637 perf_output_put(&handle
, comm_event
->event_id
);
6638 __output_copy(&handle
, comm_event
->comm
,
6639 comm_event
->comm_size
);
6641 perf_event__output_id_sample(event
, &handle
, &sample
);
6643 perf_output_end(&handle
);
6645 comm_event
->event_id
.header
.size
= size
;
6648 static void perf_event_comm_event(struct perf_comm_event
*comm_event
)
6650 char comm
[TASK_COMM_LEN
];
6653 memset(comm
, 0, sizeof(comm
));
6654 strlcpy(comm
, comm_event
->task
->comm
, sizeof(comm
));
6655 size
= ALIGN(strlen(comm
)+1, sizeof(u64
));
6657 comm_event
->comm
= comm
;
6658 comm_event
->comm_size
= size
;
6660 comm_event
->event_id
.header
.size
= sizeof(comm_event
->event_id
) + size
;
6662 perf_iterate_sb(perf_event_comm_output
,
6667 void perf_event_comm(struct task_struct
*task
, bool exec
)
6669 struct perf_comm_event comm_event
;
6671 if (!atomic_read(&nr_comm_events
))
6674 comm_event
= (struct perf_comm_event
){
6680 .type
= PERF_RECORD_COMM
,
6681 .misc
= exec
? PERF_RECORD_MISC_COMM_EXEC
: 0,
6689 perf_event_comm_event(&comm_event
);
6693 * namespaces tracking
6696 struct perf_namespaces_event
{
6697 struct task_struct
*task
;
6700 struct perf_event_header header
;
6705 struct perf_ns_link_info link_info
[NR_NAMESPACES
];
6709 static int perf_event_namespaces_match(struct perf_event
*event
)
6711 return event
->attr
.namespaces
;
6714 static void perf_event_namespaces_output(struct perf_event
*event
,
6717 struct perf_namespaces_event
*namespaces_event
= data
;
6718 struct perf_output_handle handle
;
6719 struct perf_sample_data sample
;
6722 if (!perf_event_namespaces_match(event
))
6725 perf_event_header__init_id(&namespaces_event
->event_id
.header
,
6727 ret
= perf_output_begin(&handle
, event
,
6728 namespaces_event
->event_id
.header
.size
);
6732 namespaces_event
->event_id
.pid
= perf_event_pid(event
,
6733 namespaces_event
->task
);
6734 namespaces_event
->event_id
.tid
= perf_event_tid(event
,
6735 namespaces_event
->task
);
6737 perf_output_put(&handle
, namespaces_event
->event_id
);
6739 perf_event__output_id_sample(event
, &handle
, &sample
);
6741 perf_output_end(&handle
);
6744 static void perf_fill_ns_link_info(struct perf_ns_link_info
*ns_link_info
,
6745 struct task_struct
*task
,
6746 const struct proc_ns_operations
*ns_ops
)
6748 struct path ns_path
;
6749 struct inode
*ns_inode
;
6752 error
= ns_get_path(&ns_path
, task
, ns_ops
);
6754 ns_inode
= ns_path
.dentry
->d_inode
;
6755 ns_link_info
->dev
= new_encode_dev(ns_inode
->i_sb
->s_dev
);
6756 ns_link_info
->ino
= ns_inode
->i_ino
;
6760 void perf_event_namespaces(struct task_struct
*task
)
6762 struct perf_namespaces_event namespaces_event
;
6763 struct perf_ns_link_info
*ns_link_info
;
6765 if (!atomic_read(&nr_namespaces_events
))
6768 namespaces_event
= (struct perf_namespaces_event
){
6772 .type
= PERF_RECORD_NAMESPACES
,
6774 .size
= sizeof(namespaces_event
.event_id
),
6778 .nr_namespaces
= NR_NAMESPACES
,
6779 /* .link_info[NR_NAMESPACES] */
6783 ns_link_info
= namespaces_event
.event_id
.link_info
;
6785 perf_fill_ns_link_info(&ns_link_info
[MNT_NS_INDEX
],
6786 task
, &mntns_operations
);
6788 #ifdef CONFIG_USER_NS
6789 perf_fill_ns_link_info(&ns_link_info
[USER_NS_INDEX
],
6790 task
, &userns_operations
);
6792 #ifdef CONFIG_NET_NS
6793 perf_fill_ns_link_info(&ns_link_info
[NET_NS_INDEX
],
6794 task
, &netns_operations
);
6796 #ifdef CONFIG_UTS_NS
6797 perf_fill_ns_link_info(&ns_link_info
[UTS_NS_INDEX
],
6798 task
, &utsns_operations
);
6800 #ifdef CONFIG_IPC_NS
6801 perf_fill_ns_link_info(&ns_link_info
[IPC_NS_INDEX
],
6802 task
, &ipcns_operations
);
6804 #ifdef CONFIG_PID_NS
6805 perf_fill_ns_link_info(&ns_link_info
[PID_NS_INDEX
],
6806 task
, &pidns_operations
);
6808 #ifdef CONFIG_CGROUPS
6809 perf_fill_ns_link_info(&ns_link_info
[CGROUP_NS_INDEX
],
6810 task
, &cgroupns_operations
);
6813 perf_iterate_sb(perf_event_namespaces_output
,
6822 struct perf_mmap_event
{
6823 struct vm_area_struct
*vma
;
6825 const char *file_name
;
6833 struct perf_event_header header
;
6843 static int perf_event_mmap_match(struct perf_event
*event
,
6846 struct perf_mmap_event
*mmap_event
= data
;
6847 struct vm_area_struct
*vma
= mmap_event
->vma
;
6848 int executable
= vma
->vm_flags
& VM_EXEC
;
6850 return (!executable
&& event
->attr
.mmap_data
) ||
6851 (executable
&& (event
->attr
.mmap
|| event
->attr
.mmap2
));
6854 static void perf_event_mmap_output(struct perf_event
*event
,
6857 struct perf_mmap_event
*mmap_event
= data
;
6858 struct perf_output_handle handle
;
6859 struct perf_sample_data sample
;
6860 int size
= mmap_event
->event_id
.header
.size
;
6863 if (!perf_event_mmap_match(event
, data
))
6866 if (event
->attr
.mmap2
) {
6867 mmap_event
->event_id
.header
.type
= PERF_RECORD_MMAP2
;
6868 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->maj
);
6869 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->min
);
6870 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->ino
);
6871 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->ino_generation
);
6872 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->prot
);
6873 mmap_event
->event_id
.header
.size
+= sizeof(mmap_event
->flags
);
6876 perf_event_header__init_id(&mmap_event
->event_id
.header
, &sample
, event
);
6877 ret
= perf_output_begin(&handle
, event
,
6878 mmap_event
->event_id
.header
.size
);
6882 mmap_event
->event_id
.pid
= perf_event_pid(event
, current
);
6883 mmap_event
->event_id
.tid
= perf_event_tid(event
, current
);
6885 perf_output_put(&handle
, mmap_event
->event_id
);
6887 if (event
->attr
.mmap2
) {
6888 perf_output_put(&handle
, mmap_event
->maj
);
6889 perf_output_put(&handle
, mmap_event
->min
);
6890 perf_output_put(&handle
, mmap_event
->ino
);
6891 perf_output_put(&handle
, mmap_event
->ino_generation
);
6892 perf_output_put(&handle
, mmap_event
->prot
);
6893 perf_output_put(&handle
, mmap_event
->flags
);
6896 __output_copy(&handle
, mmap_event
->file_name
,
6897 mmap_event
->file_size
);
6899 perf_event__output_id_sample(event
, &handle
, &sample
);
6901 perf_output_end(&handle
);
6903 mmap_event
->event_id
.header
.size
= size
;
6906 static void perf_event_mmap_event(struct perf_mmap_event
*mmap_event
)
6908 struct vm_area_struct
*vma
= mmap_event
->vma
;
6909 struct file
*file
= vma
->vm_file
;
6910 int maj
= 0, min
= 0;
6911 u64 ino
= 0, gen
= 0;
6912 u32 prot
= 0, flags
= 0;
6918 if (vma
->vm_flags
& VM_READ
)
6920 if (vma
->vm_flags
& VM_WRITE
)
6922 if (vma
->vm_flags
& VM_EXEC
)
6925 if (vma
->vm_flags
& VM_MAYSHARE
)
6928 flags
= MAP_PRIVATE
;
6930 if (vma
->vm_flags
& VM_DENYWRITE
)
6931 flags
|= MAP_DENYWRITE
;
6932 if (vma
->vm_flags
& VM_MAYEXEC
)
6933 flags
|= MAP_EXECUTABLE
;
6934 if (vma
->vm_flags
& VM_LOCKED
)
6935 flags
|= MAP_LOCKED
;
6936 if (vma
->vm_flags
& VM_HUGETLB
)
6937 flags
|= MAP_HUGETLB
;
6940 struct inode
*inode
;
6943 buf
= kmalloc(PATH_MAX
, GFP_KERNEL
);
6949 * d_path() works from the end of the rb backwards, so we
6950 * need to add enough zero bytes after the string to handle
6951 * the 64bit alignment we do later.
6953 name
= file_path(file
, buf
, PATH_MAX
- sizeof(u64
));
6958 inode
= file_inode(vma
->vm_file
);
6959 dev
= inode
->i_sb
->s_dev
;
6961 gen
= inode
->i_generation
;
6967 if (vma
->vm_ops
&& vma
->vm_ops
->name
) {
6968 name
= (char *) vma
->vm_ops
->name(vma
);
6973 name
= (char *)arch_vma_name(vma
);
6977 if (vma
->vm_start
<= vma
->vm_mm
->start_brk
&&
6978 vma
->vm_end
>= vma
->vm_mm
->brk
) {
6982 if (vma
->vm_start
<= vma
->vm_mm
->start_stack
&&
6983 vma
->vm_end
>= vma
->vm_mm
->start_stack
) {
6993 strlcpy(tmp
, name
, sizeof(tmp
));
6997 * Since our buffer works in 8 byte units we need to align our string
6998 * size to a multiple of 8. However, we must guarantee the tail end is
6999 * zero'd out to avoid leaking random bits to userspace.
7001 size
= strlen(name
)+1;
7002 while (!IS_ALIGNED(size
, sizeof(u64
)))
7003 name
[size
++] = '\0';
7005 mmap_event
->file_name
= name
;
7006 mmap_event
->file_size
= size
;
7007 mmap_event
->maj
= maj
;
7008 mmap_event
->min
= min
;
7009 mmap_event
->ino
= ino
;
7010 mmap_event
->ino_generation
= gen
;
7011 mmap_event
->prot
= prot
;
7012 mmap_event
->flags
= flags
;
7014 if (!(vma
->vm_flags
& VM_EXEC
))
7015 mmap_event
->event_id
.header
.misc
|= PERF_RECORD_MISC_MMAP_DATA
;
7017 mmap_event
->event_id
.header
.size
= sizeof(mmap_event
->event_id
) + size
;
7019 perf_iterate_sb(perf_event_mmap_output
,
7027 * Check whether inode and address range match filter criteria.
7029 static bool perf_addr_filter_match(struct perf_addr_filter
*filter
,
7030 struct file
*file
, unsigned long offset
,
7033 if (filter
->inode
!= file_inode(file
))
7036 if (filter
->offset
> offset
+ size
)
7039 if (filter
->offset
+ filter
->size
< offset
)
7045 static void __perf_addr_filters_adjust(struct perf_event
*event
, void *data
)
7047 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
7048 struct vm_area_struct
*vma
= data
;
7049 unsigned long off
= vma
->vm_pgoff
<< PAGE_SHIFT
, flags
;
7050 struct file
*file
= vma
->vm_file
;
7051 struct perf_addr_filter
*filter
;
7052 unsigned int restart
= 0, count
= 0;
7054 if (!has_addr_filter(event
))
7060 raw_spin_lock_irqsave(&ifh
->lock
, flags
);
7061 list_for_each_entry(filter
, &ifh
->list
, entry
) {
7062 if (perf_addr_filter_match(filter
, file
, off
,
7063 vma
->vm_end
- vma
->vm_start
)) {
7064 event
->addr_filters_offs
[count
] = vma
->vm_start
;
7072 event
->addr_filters_gen
++;
7073 raw_spin_unlock_irqrestore(&ifh
->lock
, flags
);
7076 perf_event_stop(event
, 1);
7080 * Adjust all task's events' filters to the new vma
7082 static void perf_addr_filters_adjust(struct vm_area_struct
*vma
)
7084 struct perf_event_context
*ctx
;
7088 * Data tracing isn't supported yet and as such there is no need
7089 * to keep track of anything that isn't related to executable code:
7091 if (!(vma
->vm_flags
& VM_EXEC
))
7095 for_each_task_context_nr(ctxn
) {
7096 ctx
= rcu_dereference(current
->perf_event_ctxp
[ctxn
]);
7100 perf_iterate_ctx(ctx
, __perf_addr_filters_adjust
, vma
, true);
7105 void perf_event_mmap(struct vm_area_struct
*vma
)
7107 struct perf_mmap_event mmap_event
;
7109 if (!atomic_read(&nr_mmap_events
))
7112 mmap_event
= (struct perf_mmap_event
){
7118 .type
= PERF_RECORD_MMAP
,
7119 .misc
= PERF_RECORD_MISC_USER
,
7124 .start
= vma
->vm_start
,
7125 .len
= vma
->vm_end
- vma
->vm_start
,
7126 .pgoff
= (u64
)vma
->vm_pgoff
<< PAGE_SHIFT
,
7128 /* .maj (attr_mmap2 only) */
7129 /* .min (attr_mmap2 only) */
7130 /* .ino (attr_mmap2 only) */
7131 /* .ino_generation (attr_mmap2 only) */
7132 /* .prot (attr_mmap2 only) */
7133 /* .flags (attr_mmap2 only) */
7136 perf_addr_filters_adjust(vma
);
7137 perf_event_mmap_event(&mmap_event
);
7140 void perf_event_aux_event(struct perf_event
*event
, unsigned long head
,
7141 unsigned long size
, u64 flags
)
7143 struct perf_output_handle handle
;
7144 struct perf_sample_data sample
;
7145 struct perf_aux_event
{
7146 struct perf_event_header header
;
7152 .type
= PERF_RECORD_AUX
,
7154 .size
= sizeof(rec
),
7162 perf_event_header__init_id(&rec
.header
, &sample
, event
);
7163 ret
= perf_output_begin(&handle
, event
, rec
.header
.size
);
7168 perf_output_put(&handle
, rec
);
7169 perf_event__output_id_sample(event
, &handle
, &sample
);
7171 perf_output_end(&handle
);
7175 * Lost/dropped samples logging
7177 void perf_log_lost_samples(struct perf_event
*event
, u64 lost
)
7179 struct perf_output_handle handle
;
7180 struct perf_sample_data sample
;
7184 struct perf_event_header header
;
7186 } lost_samples_event
= {
7188 .type
= PERF_RECORD_LOST_SAMPLES
,
7190 .size
= sizeof(lost_samples_event
),
7195 perf_event_header__init_id(&lost_samples_event
.header
, &sample
, event
);
7197 ret
= perf_output_begin(&handle
, event
,
7198 lost_samples_event
.header
.size
);
7202 perf_output_put(&handle
, lost_samples_event
);
7203 perf_event__output_id_sample(event
, &handle
, &sample
);
7204 perf_output_end(&handle
);
7208 * context_switch tracking
7211 struct perf_switch_event
{
7212 struct task_struct
*task
;
7213 struct task_struct
*next_prev
;
7216 struct perf_event_header header
;
7222 static int perf_event_switch_match(struct perf_event
*event
)
7224 return event
->attr
.context_switch
;
7227 static void perf_event_switch_output(struct perf_event
*event
, void *data
)
7229 struct perf_switch_event
*se
= data
;
7230 struct perf_output_handle handle
;
7231 struct perf_sample_data sample
;
7234 if (!perf_event_switch_match(event
))
7237 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7238 if (event
->ctx
->task
) {
7239 se
->event_id
.header
.type
= PERF_RECORD_SWITCH
;
7240 se
->event_id
.header
.size
= sizeof(se
->event_id
.header
);
7242 se
->event_id
.header
.type
= PERF_RECORD_SWITCH_CPU_WIDE
;
7243 se
->event_id
.header
.size
= sizeof(se
->event_id
);
7244 se
->event_id
.next_prev_pid
=
7245 perf_event_pid(event
, se
->next_prev
);
7246 se
->event_id
.next_prev_tid
=
7247 perf_event_tid(event
, se
->next_prev
);
7250 perf_event_header__init_id(&se
->event_id
.header
, &sample
, event
);
7252 ret
= perf_output_begin(&handle
, event
, se
->event_id
.header
.size
);
7256 if (event
->ctx
->task
)
7257 perf_output_put(&handle
, se
->event_id
.header
);
7259 perf_output_put(&handle
, se
->event_id
);
7261 perf_event__output_id_sample(event
, &handle
, &sample
);
7263 perf_output_end(&handle
);
7266 static void perf_event_switch(struct task_struct
*task
,
7267 struct task_struct
*next_prev
, bool sched_in
)
7269 struct perf_switch_event switch_event
;
7271 /* N.B. caller checks nr_switch_events != 0 */
7273 switch_event
= (struct perf_switch_event
){
7275 .next_prev
= next_prev
,
7279 .misc
= sched_in
? 0 : PERF_RECORD_MISC_SWITCH_OUT
,
7282 /* .next_prev_pid */
7283 /* .next_prev_tid */
7287 perf_iterate_sb(perf_event_switch_output
,
7293 * IRQ throttle logging
7296 static void perf_log_throttle(struct perf_event
*event
, int enable
)
7298 struct perf_output_handle handle
;
7299 struct perf_sample_data sample
;
7303 struct perf_event_header header
;
7307 } throttle_event
= {
7309 .type
= PERF_RECORD_THROTTLE
,
7311 .size
= sizeof(throttle_event
),
7313 .time
= perf_event_clock(event
),
7314 .id
= primary_event_id(event
),
7315 .stream_id
= event
->id
,
7319 throttle_event
.header
.type
= PERF_RECORD_UNTHROTTLE
;
7321 perf_event_header__init_id(&throttle_event
.header
, &sample
, event
);
7323 ret
= perf_output_begin(&handle
, event
,
7324 throttle_event
.header
.size
);
7328 perf_output_put(&handle
, throttle_event
);
7329 perf_event__output_id_sample(event
, &handle
, &sample
);
7330 perf_output_end(&handle
);
7333 void perf_event_itrace_started(struct perf_event
*event
)
7335 event
->attach_state
|= PERF_ATTACH_ITRACE
;
7338 static void perf_log_itrace_start(struct perf_event
*event
)
7340 struct perf_output_handle handle
;
7341 struct perf_sample_data sample
;
7342 struct perf_aux_event
{
7343 struct perf_event_header header
;
7350 event
= event
->parent
;
7352 if (!(event
->pmu
->capabilities
& PERF_PMU_CAP_ITRACE
) ||
7353 event
->attach_state
& PERF_ATTACH_ITRACE
)
7356 rec
.header
.type
= PERF_RECORD_ITRACE_START
;
7357 rec
.header
.misc
= 0;
7358 rec
.header
.size
= sizeof(rec
);
7359 rec
.pid
= perf_event_pid(event
, current
);
7360 rec
.tid
= perf_event_tid(event
, current
);
7362 perf_event_header__init_id(&rec
.header
, &sample
, event
);
7363 ret
= perf_output_begin(&handle
, event
, rec
.header
.size
);
7368 perf_output_put(&handle
, rec
);
7369 perf_event__output_id_sample(event
, &handle
, &sample
);
7371 perf_output_end(&handle
);
7375 __perf_event_account_interrupt(struct perf_event
*event
, int throttle
)
7377 struct hw_perf_event
*hwc
= &event
->hw
;
7381 seq
= __this_cpu_read(perf_throttled_seq
);
7382 if (seq
!= hwc
->interrupts_seq
) {
7383 hwc
->interrupts_seq
= seq
;
7384 hwc
->interrupts
= 1;
7387 if (unlikely(throttle
7388 && hwc
->interrupts
>= max_samples_per_tick
)) {
7389 __this_cpu_inc(perf_throttled_count
);
7390 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS
);
7391 hwc
->interrupts
= MAX_INTERRUPTS
;
7392 perf_log_throttle(event
, 0);
7397 if (event
->attr
.freq
) {
7398 u64 now
= perf_clock();
7399 s64 delta
= now
- hwc
->freq_time_stamp
;
7401 hwc
->freq_time_stamp
= now
;
7403 if (delta
> 0 && delta
< 2*TICK_NSEC
)
7404 perf_adjust_period(event
, delta
, hwc
->last_period
, true);
7410 int perf_event_account_interrupt(struct perf_event
*event
)
7412 return __perf_event_account_interrupt(event
, 1);
7416 * Generic event overflow handling, sampling.
7419 static int __perf_event_overflow(struct perf_event
*event
,
7420 int throttle
, struct perf_sample_data
*data
,
7421 struct pt_regs
*regs
)
7423 int events
= atomic_read(&event
->event_limit
);
7427 * Non-sampling counters might still use the PMI to fold short
7428 * hardware counters, ignore those.
7430 if (unlikely(!is_sampling_event(event
)))
7433 ret
= __perf_event_account_interrupt(event
, throttle
);
7436 * XXX event_limit might not quite work as expected on inherited
7440 event
->pending_kill
= POLL_IN
;
7441 if (events
&& atomic_dec_and_test(&event
->event_limit
)) {
7443 event
->pending_kill
= POLL_HUP
;
7445 perf_event_disable_inatomic(event
);
7448 READ_ONCE(event
->overflow_handler
)(event
, data
, regs
);
7450 if (*perf_event_fasync(event
) && event
->pending_kill
) {
7451 event
->pending_wakeup
= 1;
7452 irq_work_queue(&event
->pending
);
7458 int perf_event_overflow(struct perf_event
*event
,
7459 struct perf_sample_data
*data
,
7460 struct pt_regs
*regs
)
7462 return __perf_event_overflow(event
, 1, data
, regs
);
7466 * Generic software event infrastructure
7469 struct swevent_htable
{
7470 struct swevent_hlist
*swevent_hlist
;
7471 struct mutex hlist_mutex
;
7474 /* Recursion avoidance in each contexts */
7475 int recursion
[PERF_NR_CONTEXTS
];
7478 static DEFINE_PER_CPU(struct swevent_htable
, swevent_htable
);
7481 * We directly increment event->count and keep a second value in
7482 * event->hw.period_left to count intervals. This period event
7483 * is kept in the range [-sample_period, 0] so that we can use the
7487 u64
perf_swevent_set_period(struct perf_event
*event
)
7489 struct hw_perf_event
*hwc
= &event
->hw
;
7490 u64 period
= hwc
->last_period
;
7494 hwc
->last_period
= hwc
->sample_period
;
7497 old
= val
= local64_read(&hwc
->period_left
);
7501 nr
= div64_u64(period
+ val
, period
);
7502 offset
= nr
* period
;
7504 if (local64_cmpxchg(&hwc
->period_left
, old
, val
) != old
)
7510 static void perf_swevent_overflow(struct perf_event
*event
, u64 overflow
,
7511 struct perf_sample_data
*data
,
7512 struct pt_regs
*regs
)
7514 struct hw_perf_event
*hwc
= &event
->hw
;
7518 overflow
= perf_swevent_set_period(event
);
7520 if (hwc
->interrupts
== MAX_INTERRUPTS
)
7523 for (; overflow
; overflow
--) {
7524 if (__perf_event_overflow(event
, throttle
,
7527 * We inhibit the overflow from happening when
7528 * hwc->interrupts == MAX_INTERRUPTS.
7536 static void perf_swevent_event(struct perf_event
*event
, u64 nr
,
7537 struct perf_sample_data
*data
,
7538 struct pt_regs
*regs
)
7540 struct hw_perf_event
*hwc
= &event
->hw
;
7542 local64_add(nr
, &event
->count
);
7547 if (!is_sampling_event(event
))
7550 if ((event
->attr
.sample_type
& PERF_SAMPLE_PERIOD
) && !event
->attr
.freq
) {
7552 return perf_swevent_overflow(event
, 1, data
, regs
);
7554 data
->period
= event
->hw
.last_period
;
7556 if (nr
== 1 && hwc
->sample_period
== 1 && !event
->attr
.freq
)
7557 return perf_swevent_overflow(event
, 1, data
, regs
);
7559 if (local64_add_negative(nr
, &hwc
->period_left
))
7562 perf_swevent_overflow(event
, 0, data
, regs
);
7565 static int perf_exclude_event(struct perf_event
*event
,
7566 struct pt_regs
*regs
)
7568 if (event
->hw
.state
& PERF_HES_STOPPED
)
7572 if (event
->attr
.exclude_user
&& user_mode(regs
))
7575 if (event
->attr
.exclude_kernel
&& !user_mode(regs
))
7582 static int perf_swevent_match(struct perf_event
*event
,
7583 enum perf_type_id type
,
7585 struct perf_sample_data
*data
,
7586 struct pt_regs
*regs
)
7588 if (event
->attr
.type
!= type
)
7591 if (event
->attr
.config
!= event_id
)
7594 if (perf_exclude_event(event
, regs
))
7600 static inline u64
swevent_hash(u64 type
, u32 event_id
)
7602 u64 val
= event_id
| (type
<< 32);
7604 return hash_64(val
, SWEVENT_HLIST_BITS
);
7607 static inline struct hlist_head
*
7608 __find_swevent_head(struct swevent_hlist
*hlist
, u64 type
, u32 event_id
)
7610 u64 hash
= swevent_hash(type
, event_id
);
7612 return &hlist
->heads
[hash
];
7615 /* For the read side: events when they trigger */
7616 static inline struct hlist_head
*
7617 find_swevent_head_rcu(struct swevent_htable
*swhash
, u64 type
, u32 event_id
)
7619 struct swevent_hlist
*hlist
;
7621 hlist
= rcu_dereference(swhash
->swevent_hlist
);
7625 return __find_swevent_head(hlist
, type
, event_id
);
7628 /* For the event head insertion and removal in the hlist */
7629 static inline struct hlist_head
*
7630 find_swevent_head(struct swevent_htable
*swhash
, struct perf_event
*event
)
7632 struct swevent_hlist
*hlist
;
7633 u32 event_id
= event
->attr
.config
;
7634 u64 type
= event
->attr
.type
;
7637 * Event scheduling is always serialized against hlist allocation
7638 * and release. Which makes the protected version suitable here.
7639 * The context lock guarantees that.
7641 hlist
= rcu_dereference_protected(swhash
->swevent_hlist
,
7642 lockdep_is_held(&event
->ctx
->lock
));
7646 return __find_swevent_head(hlist
, type
, event_id
);
7649 static void do_perf_sw_event(enum perf_type_id type
, u32 event_id
,
7651 struct perf_sample_data
*data
,
7652 struct pt_regs
*regs
)
7654 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7655 struct perf_event
*event
;
7656 struct hlist_head
*head
;
7659 head
= find_swevent_head_rcu(swhash
, type
, event_id
);
7663 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
7664 if (perf_swevent_match(event
, type
, event_id
, data
, regs
))
7665 perf_swevent_event(event
, nr
, data
, regs
);
7671 DEFINE_PER_CPU(struct pt_regs
, __perf_regs
[4]);
7673 int perf_swevent_get_recursion_context(void)
7675 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7677 return get_recursion_context(swhash
->recursion
);
7679 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context
);
7681 void perf_swevent_put_recursion_context(int rctx
)
7683 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7685 put_recursion_context(swhash
->recursion
, rctx
);
7688 void ___perf_sw_event(u32 event_id
, u64 nr
, struct pt_regs
*regs
, u64 addr
)
7690 struct perf_sample_data data
;
7692 if (WARN_ON_ONCE(!regs
))
7695 perf_sample_data_init(&data
, addr
, 0);
7696 do_perf_sw_event(PERF_TYPE_SOFTWARE
, event_id
, nr
, &data
, regs
);
7699 void __perf_sw_event(u32 event_id
, u64 nr
, struct pt_regs
*regs
, u64 addr
)
7703 preempt_disable_notrace();
7704 rctx
= perf_swevent_get_recursion_context();
7705 if (unlikely(rctx
< 0))
7708 ___perf_sw_event(event_id
, nr
, regs
, addr
);
7710 perf_swevent_put_recursion_context(rctx
);
7712 preempt_enable_notrace();
7715 static void perf_swevent_read(struct perf_event
*event
)
7719 static int perf_swevent_add(struct perf_event
*event
, int flags
)
7721 struct swevent_htable
*swhash
= this_cpu_ptr(&swevent_htable
);
7722 struct hw_perf_event
*hwc
= &event
->hw
;
7723 struct hlist_head
*head
;
7725 if (is_sampling_event(event
)) {
7726 hwc
->last_period
= hwc
->sample_period
;
7727 perf_swevent_set_period(event
);
7730 hwc
->state
= !(flags
& PERF_EF_START
);
7732 head
= find_swevent_head(swhash
, event
);
7733 if (WARN_ON_ONCE(!head
))
7736 hlist_add_head_rcu(&event
->hlist_entry
, head
);
7737 perf_event_update_userpage(event
);
7742 static void perf_swevent_del(struct perf_event
*event
, int flags
)
7744 hlist_del_rcu(&event
->hlist_entry
);
7747 static void perf_swevent_start(struct perf_event
*event
, int flags
)
7749 event
->hw
.state
= 0;
7752 static void perf_swevent_stop(struct perf_event
*event
, int flags
)
7754 event
->hw
.state
= PERF_HES_STOPPED
;
7757 /* Deref the hlist from the update side */
7758 static inline struct swevent_hlist
*
7759 swevent_hlist_deref(struct swevent_htable
*swhash
)
7761 return rcu_dereference_protected(swhash
->swevent_hlist
,
7762 lockdep_is_held(&swhash
->hlist_mutex
));
7765 static void swevent_hlist_release(struct swevent_htable
*swhash
)
7767 struct swevent_hlist
*hlist
= swevent_hlist_deref(swhash
);
7772 RCU_INIT_POINTER(swhash
->swevent_hlist
, NULL
);
7773 kfree_rcu(hlist
, rcu_head
);
7776 static void swevent_hlist_put_cpu(int cpu
)
7778 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
7780 mutex_lock(&swhash
->hlist_mutex
);
7782 if (!--swhash
->hlist_refcount
)
7783 swevent_hlist_release(swhash
);
7785 mutex_unlock(&swhash
->hlist_mutex
);
7788 static void swevent_hlist_put(void)
7792 for_each_possible_cpu(cpu
)
7793 swevent_hlist_put_cpu(cpu
);
7796 static int swevent_hlist_get_cpu(int cpu
)
7798 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
7801 mutex_lock(&swhash
->hlist_mutex
);
7802 if (!swevent_hlist_deref(swhash
) &&
7803 cpumask_test_cpu(cpu
, perf_online_mask
)) {
7804 struct swevent_hlist
*hlist
;
7806 hlist
= kzalloc(sizeof(*hlist
), GFP_KERNEL
);
7811 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
7813 swhash
->hlist_refcount
++;
7815 mutex_unlock(&swhash
->hlist_mutex
);
7820 static int swevent_hlist_get(void)
7822 int err
, cpu
, failed_cpu
;
7824 mutex_lock(&pmus_lock
);
7825 for_each_possible_cpu(cpu
) {
7826 err
= swevent_hlist_get_cpu(cpu
);
7832 mutex_unlock(&pmus_lock
);
7835 for_each_possible_cpu(cpu
) {
7836 if (cpu
== failed_cpu
)
7838 swevent_hlist_put_cpu(cpu
);
7840 mutex_unlock(&pmus_lock
);
7844 struct static_key perf_swevent_enabled
[PERF_COUNT_SW_MAX
];
7846 static void sw_perf_event_destroy(struct perf_event
*event
)
7848 u64 event_id
= event
->attr
.config
;
7850 WARN_ON(event
->parent
);
7852 static_key_slow_dec(&perf_swevent_enabled
[event_id
]);
7853 swevent_hlist_put();
7856 static int perf_swevent_init(struct perf_event
*event
)
7858 u64 event_id
= event
->attr
.config
;
7860 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
7864 * no branch sampling for software events
7866 if (has_branch_stack(event
))
7870 case PERF_COUNT_SW_CPU_CLOCK
:
7871 case PERF_COUNT_SW_TASK_CLOCK
:
7878 if (event_id
>= PERF_COUNT_SW_MAX
)
7881 if (!event
->parent
) {
7884 err
= swevent_hlist_get();
7888 static_key_slow_inc(&perf_swevent_enabled
[event_id
]);
7889 event
->destroy
= sw_perf_event_destroy
;
7895 static struct pmu perf_swevent
= {
7896 .task_ctx_nr
= perf_sw_context
,
7898 .capabilities
= PERF_PMU_CAP_NO_NMI
,
7900 .event_init
= perf_swevent_init
,
7901 .add
= perf_swevent_add
,
7902 .del
= perf_swevent_del
,
7903 .start
= perf_swevent_start
,
7904 .stop
= perf_swevent_stop
,
7905 .read
= perf_swevent_read
,
7908 #ifdef CONFIG_EVENT_TRACING
7910 static int perf_tp_filter_match(struct perf_event
*event
,
7911 struct perf_sample_data
*data
)
7913 void *record
= data
->raw
->frag
.data
;
7915 /* only top level events have filters set */
7917 event
= event
->parent
;
7919 if (likely(!event
->filter
) || filter_match_preds(event
->filter
, record
))
7924 static int perf_tp_event_match(struct perf_event
*event
,
7925 struct perf_sample_data
*data
,
7926 struct pt_regs
*regs
)
7928 if (event
->hw
.state
& PERF_HES_STOPPED
)
7931 * All tracepoints are from kernel-space.
7933 if (event
->attr
.exclude_kernel
)
7936 if (!perf_tp_filter_match(event
, data
))
7942 void perf_trace_run_bpf_submit(void *raw_data
, int size
, int rctx
,
7943 struct trace_event_call
*call
, u64 count
,
7944 struct pt_regs
*regs
, struct hlist_head
*head
,
7945 struct task_struct
*task
)
7947 struct bpf_prog
*prog
= call
->prog
;
7950 *(struct pt_regs
**)raw_data
= regs
;
7951 if (!trace_call_bpf(prog
, raw_data
) || hlist_empty(head
)) {
7952 perf_swevent_put_recursion_context(rctx
);
7956 perf_tp_event(call
->event
.type
, count
, raw_data
, size
, regs
, head
,
7959 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit
);
7961 void perf_tp_event(u16 event_type
, u64 count
, void *record
, int entry_size
,
7962 struct pt_regs
*regs
, struct hlist_head
*head
, int rctx
,
7963 struct task_struct
*task
, struct perf_event
*event
)
7965 struct perf_sample_data data
;
7967 struct perf_raw_record raw
= {
7974 perf_sample_data_init(&data
, 0, 0);
7977 perf_trace_buf_update(record
, event_type
);
7979 /* Use the given event instead of the hlist */
7981 if (perf_tp_event_match(event
, &data
, regs
))
7982 perf_swevent_event(event
, count
, &data
, regs
);
7984 hlist_for_each_entry_rcu(event
, head
, hlist_entry
) {
7985 if (perf_tp_event_match(event
, &data
, regs
))
7986 perf_swevent_event(event
, count
, &data
, regs
);
7991 * If we got specified a target task, also iterate its context and
7992 * deliver this event there too.
7994 if (task
&& task
!= current
) {
7995 struct perf_event_context
*ctx
;
7996 struct trace_entry
*entry
= record
;
7999 ctx
= rcu_dereference(task
->perf_event_ctxp
[perf_sw_context
]);
8003 list_for_each_entry_rcu(event
, &ctx
->event_list
, event_entry
) {
8004 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
8006 if (event
->attr
.config
!= entry
->type
)
8008 if (perf_tp_event_match(event
, &data
, regs
))
8009 perf_swevent_event(event
, count
, &data
, regs
);
8015 perf_swevent_put_recursion_context(rctx
);
8017 EXPORT_SYMBOL_GPL(perf_tp_event
);
8019 static void tp_perf_event_destroy(struct perf_event
*event
)
8021 perf_trace_destroy(event
);
8024 static int perf_tp_event_init(struct perf_event
*event
)
8028 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
8032 * no branch sampling for tracepoint events
8034 if (has_branch_stack(event
))
8037 err
= perf_trace_init(event
);
8041 event
->destroy
= tp_perf_event_destroy
;
8046 static struct pmu perf_tracepoint
= {
8047 .task_ctx_nr
= perf_sw_context
,
8049 .event_init
= perf_tp_event_init
,
8050 .add
= perf_trace_add
,
8051 .del
= perf_trace_del
,
8052 .start
= perf_swevent_start
,
8053 .stop
= perf_swevent_stop
,
8054 .read
= perf_swevent_read
,
8057 static inline void perf_tp_register(void)
8059 perf_pmu_register(&perf_tracepoint
, "tracepoint", PERF_TYPE_TRACEPOINT
);
8062 static void perf_event_free_filter(struct perf_event
*event
)
8064 ftrace_profile_free_filter(event
);
8067 #ifdef CONFIG_BPF_SYSCALL
8068 static void bpf_overflow_handler(struct perf_event
*event
,
8069 struct perf_sample_data
*data
,
8070 struct pt_regs
*regs
)
8072 struct bpf_perf_event_data_kern ctx
= {
8079 if (unlikely(__this_cpu_inc_return(bpf_prog_active
) != 1))
8082 ret
= BPF_PROG_RUN(event
->prog
, &ctx
);
8085 __this_cpu_dec(bpf_prog_active
);
8090 event
->orig_overflow_handler(event
, data
, regs
);
8093 static int perf_event_set_bpf_handler(struct perf_event
*event
, u32 prog_fd
)
8095 struct bpf_prog
*prog
;
8097 if (event
->overflow_handler_context
)
8098 /* hw breakpoint or kernel counter */
8104 prog
= bpf_prog_get_type(prog_fd
, BPF_PROG_TYPE_PERF_EVENT
);
8106 return PTR_ERR(prog
);
8109 event
->orig_overflow_handler
= READ_ONCE(event
->overflow_handler
);
8110 WRITE_ONCE(event
->overflow_handler
, bpf_overflow_handler
);
8114 static void perf_event_free_bpf_handler(struct perf_event
*event
)
8116 struct bpf_prog
*prog
= event
->prog
;
8121 WRITE_ONCE(event
->overflow_handler
, event
->orig_overflow_handler
);
8126 static int perf_event_set_bpf_handler(struct perf_event
*event
, u32 prog_fd
)
8130 static void perf_event_free_bpf_handler(struct perf_event
*event
)
8135 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
)
8137 bool is_kprobe
, is_tracepoint
, is_syscall_tp
;
8138 struct bpf_prog
*prog
;
8140 if (event
->attr
.type
!= PERF_TYPE_TRACEPOINT
)
8141 return perf_event_set_bpf_handler(event
, prog_fd
);
8143 if (event
->tp_event
->prog
)
8146 is_kprobe
= event
->tp_event
->flags
& TRACE_EVENT_FL_UKPROBE
;
8147 is_tracepoint
= event
->tp_event
->flags
& TRACE_EVENT_FL_TRACEPOINT
;
8148 is_syscall_tp
= is_syscall_trace_event(event
->tp_event
);
8149 if (!is_kprobe
&& !is_tracepoint
&& !is_syscall_tp
)
8150 /* bpf programs can only be attached to u/kprobe or tracepoint */
8153 prog
= bpf_prog_get(prog_fd
);
8155 return PTR_ERR(prog
);
8157 if ((is_kprobe
&& prog
->type
!= BPF_PROG_TYPE_KPROBE
) ||
8158 (is_tracepoint
&& prog
->type
!= BPF_PROG_TYPE_TRACEPOINT
) ||
8159 (is_syscall_tp
&& prog
->type
!= BPF_PROG_TYPE_TRACEPOINT
)) {
8160 /* valid fd, but invalid bpf program type */
8165 if (is_tracepoint
|| is_syscall_tp
) {
8166 int off
= trace_event_get_offsets(event
->tp_event
);
8168 if (prog
->aux
->max_ctx_offset
> off
) {
8173 event
->tp_event
->prog
= prog
;
8174 event
->tp_event
->bpf_prog_owner
= event
;
8179 static void perf_event_free_bpf_prog(struct perf_event
*event
)
8181 struct bpf_prog
*prog
;
8183 perf_event_free_bpf_handler(event
);
8185 if (!event
->tp_event
)
8188 prog
= event
->tp_event
->prog
;
8189 if (prog
&& event
->tp_event
->bpf_prog_owner
== event
) {
8190 event
->tp_event
->prog
= NULL
;
8197 static inline void perf_tp_register(void)
8201 static void perf_event_free_filter(struct perf_event
*event
)
8205 static int perf_event_set_bpf_prog(struct perf_event
*event
, u32 prog_fd
)
8210 static void perf_event_free_bpf_prog(struct perf_event
*event
)
8213 #endif /* CONFIG_EVENT_TRACING */
8215 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8216 void perf_bp_event(struct perf_event
*bp
, void *data
)
8218 struct perf_sample_data sample
;
8219 struct pt_regs
*regs
= data
;
8221 perf_sample_data_init(&sample
, bp
->attr
.bp_addr
, 0);
8223 if (!bp
->hw
.state
&& !perf_exclude_event(bp
, regs
))
8224 perf_swevent_event(bp
, 1, &sample
, regs
);
8229 * Allocate a new address filter
8231 static struct perf_addr_filter
*
8232 perf_addr_filter_new(struct perf_event
*event
, struct list_head
*filters
)
8234 int node
= cpu_to_node(event
->cpu
== -1 ? 0 : event
->cpu
);
8235 struct perf_addr_filter
*filter
;
8237 filter
= kzalloc_node(sizeof(*filter
), GFP_KERNEL
, node
);
8241 INIT_LIST_HEAD(&filter
->entry
);
8242 list_add_tail(&filter
->entry
, filters
);
8247 static void free_filters_list(struct list_head
*filters
)
8249 struct perf_addr_filter
*filter
, *iter
;
8251 list_for_each_entry_safe(filter
, iter
, filters
, entry
) {
8253 iput(filter
->inode
);
8254 list_del(&filter
->entry
);
8260 * Free existing address filters and optionally install new ones
8262 static void perf_addr_filters_splice(struct perf_event
*event
,
8263 struct list_head
*head
)
8265 unsigned long flags
;
8268 if (!has_addr_filter(event
))
8271 /* don't bother with children, they don't have their own filters */
8275 raw_spin_lock_irqsave(&event
->addr_filters
.lock
, flags
);
8277 list_splice_init(&event
->addr_filters
.list
, &list
);
8279 list_splice(head
, &event
->addr_filters
.list
);
8281 raw_spin_unlock_irqrestore(&event
->addr_filters
.lock
, flags
);
8283 free_filters_list(&list
);
8287 * Scan through mm's vmas and see if one of them matches the
8288 * @filter; if so, adjust filter's address range.
8289 * Called with mm::mmap_sem down for reading.
8291 static unsigned long perf_addr_filter_apply(struct perf_addr_filter
*filter
,
8292 struct mm_struct
*mm
)
8294 struct vm_area_struct
*vma
;
8296 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
8297 struct file
*file
= vma
->vm_file
;
8298 unsigned long off
= vma
->vm_pgoff
<< PAGE_SHIFT
;
8299 unsigned long vma_size
= vma
->vm_end
- vma
->vm_start
;
8304 if (!perf_addr_filter_match(filter
, file
, off
, vma_size
))
8307 return vma
->vm_start
;
8314 * Update event's address range filters based on the
8315 * task's existing mappings, if any.
8317 static void perf_event_addr_filters_apply(struct perf_event
*event
)
8319 struct perf_addr_filters_head
*ifh
= perf_event_addr_filters(event
);
8320 struct task_struct
*task
= READ_ONCE(event
->ctx
->task
);
8321 struct perf_addr_filter
*filter
;
8322 struct mm_struct
*mm
= NULL
;
8323 unsigned int count
= 0;
8324 unsigned long flags
;
8327 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8328 * will stop on the parent's child_mutex that our caller is also holding
8330 if (task
== TASK_TOMBSTONE
)
8333 if (!ifh
->nr_file_filters
)
8336 mm
= get_task_mm(event
->ctx
->task
);
8340 down_read(&mm
->mmap_sem
);
8342 raw_spin_lock_irqsave(&ifh
->lock
, flags
);
8343 list_for_each_entry(filter
, &ifh
->list
, entry
) {
8344 event
->addr_filters_offs
[count
] = 0;
8347 * Adjust base offset if the filter is associated to a binary
8348 * that needs to be mapped:
8351 event
->addr_filters_offs
[count
] =
8352 perf_addr_filter_apply(filter
, mm
);
8357 event
->addr_filters_gen
++;
8358 raw_spin_unlock_irqrestore(&ifh
->lock
, flags
);
8360 up_read(&mm
->mmap_sem
);
8365 perf_event_stop(event
, 1);
8369 * Address range filtering: limiting the data to certain
8370 * instruction address ranges. Filters are ioctl()ed to us from
8371 * userspace as ascii strings.
8373 * Filter string format:
8376 * where ACTION is one of the
8377 * * "filter": limit the trace to this region
8378 * * "start": start tracing from this address
8379 * * "stop": stop tracing at this address/region;
8381 * * for kernel addresses: <start address>[/<size>]
8382 * * for object files: <start address>[/<size>]@</path/to/object/file>
8384 * if <size> is not specified, the range is treated as a single address.
8398 IF_STATE_ACTION
= 0,
8403 static const match_table_t if_tokens
= {
8404 { IF_ACT_FILTER
, "filter" },
8405 { IF_ACT_START
, "start" },
8406 { IF_ACT_STOP
, "stop" },
8407 { IF_SRC_FILE
, "%u/%u@%s" },
8408 { IF_SRC_KERNEL
, "%u/%u" },
8409 { IF_SRC_FILEADDR
, "%u@%s" },
8410 { IF_SRC_KERNELADDR
, "%u" },
8411 { IF_ACT_NONE
, NULL
},
8415 * Address filter string parser
8418 perf_event_parse_addr_filter(struct perf_event
*event
, char *fstr
,
8419 struct list_head
*filters
)
8421 struct perf_addr_filter
*filter
= NULL
;
8422 char *start
, *orig
, *filename
= NULL
;
8424 substring_t args
[MAX_OPT_ARGS
];
8425 int state
= IF_STATE_ACTION
, token
;
8426 unsigned int kernel
= 0;
8429 orig
= fstr
= kstrdup(fstr
, GFP_KERNEL
);
8433 while ((start
= strsep(&fstr
, " ,\n")) != NULL
) {
8439 /* filter definition begins */
8440 if (state
== IF_STATE_ACTION
) {
8441 filter
= perf_addr_filter_new(event
, filters
);
8446 token
= match_token(start
, if_tokens
, args
);
8453 if (state
!= IF_STATE_ACTION
)
8456 state
= IF_STATE_SOURCE
;
8459 case IF_SRC_KERNELADDR
:
8463 case IF_SRC_FILEADDR
:
8465 if (state
!= IF_STATE_SOURCE
)
8468 if (token
== IF_SRC_FILE
|| token
== IF_SRC_KERNEL
)
8472 ret
= kstrtoul(args
[0].from
, 0, &filter
->offset
);
8476 if (filter
->range
) {
8478 ret
= kstrtoul(args
[1].from
, 0, &filter
->size
);
8483 if (token
== IF_SRC_FILE
|| token
== IF_SRC_FILEADDR
) {
8484 int fpos
= filter
->range
? 2 : 1;
8486 filename
= match_strdup(&args
[fpos
]);
8493 state
= IF_STATE_END
;
8501 * Filter definition is fully parsed, validate and install it.
8502 * Make sure that it doesn't contradict itself or the event's
8505 if (state
== IF_STATE_END
) {
8507 if (kernel
&& event
->attr
.exclude_kernel
)
8515 * For now, we only support file-based filters
8516 * in per-task events; doing so for CPU-wide
8517 * events requires additional context switching
8518 * trickery, since same object code will be
8519 * mapped at different virtual addresses in
8520 * different processes.
8523 if (!event
->ctx
->task
)
8524 goto fail_free_name
;
8526 /* look up the path and grab its inode */
8527 ret
= kern_path(filename
, LOOKUP_FOLLOW
, &path
);
8529 goto fail_free_name
;
8531 filter
->inode
= igrab(d_inode(path
.dentry
));
8537 if (!filter
->inode
||
8538 !S_ISREG(filter
->inode
->i_mode
))
8539 /* free_filters_list() will iput() */
8542 event
->addr_filters
.nr_file_filters
++;
8545 /* ready to consume more filters */
8546 state
= IF_STATE_ACTION
;
8551 if (state
!= IF_STATE_ACTION
)
8561 free_filters_list(filters
);
8568 perf_event_set_addr_filter(struct perf_event
*event
, char *filter_str
)
8574 * Since this is called in perf_ioctl() path, we're already holding
8577 lockdep_assert_held(&event
->ctx
->mutex
);
8579 if (WARN_ON_ONCE(event
->parent
))
8582 ret
= perf_event_parse_addr_filter(event
, filter_str
, &filters
);
8584 goto fail_clear_files
;
8586 ret
= event
->pmu
->addr_filters_validate(&filters
);
8588 goto fail_free_filters
;
8590 /* remove existing filters, if any */
8591 perf_addr_filters_splice(event
, &filters
);
8593 /* install new filters */
8594 perf_event_for_each_child(event
, perf_event_addr_filters_apply
);
8599 free_filters_list(&filters
);
8602 event
->addr_filters
.nr_file_filters
= 0;
8607 static int perf_event_set_filter(struct perf_event
*event
, void __user
*arg
)
8612 if ((event
->attr
.type
!= PERF_TYPE_TRACEPOINT
||
8613 !IS_ENABLED(CONFIG_EVENT_TRACING
)) &&
8614 !has_addr_filter(event
))
8617 filter_str
= strndup_user(arg
, PAGE_SIZE
);
8618 if (IS_ERR(filter_str
))
8619 return PTR_ERR(filter_str
);
8621 if (IS_ENABLED(CONFIG_EVENT_TRACING
) &&
8622 event
->attr
.type
== PERF_TYPE_TRACEPOINT
)
8623 ret
= ftrace_profile_set_filter(event
, event
->attr
.config
,
8625 else if (has_addr_filter(event
))
8626 ret
= perf_event_set_addr_filter(event
, filter_str
);
8633 * hrtimer based swevent callback
8636 static enum hrtimer_restart
perf_swevent_hrtimer(struct hrtimer
*hrtimer
)
8638 enum hrtimer_restart ret
= HRTIMER_RESTART
;
8639 struct perf_sample_data data
;
8640 struct pt_regs
*regs
;
8641 struct perf_event
*event
;
8644 event
= container_of(hrtimer
, struct perf_event
, hw
.hrtimer
);
8646 if (event
->state
!= PERF_EVENT_STATE_ACTIVE
)
8647 return HRTIMER_NORESTART
;
8649 event
->pmu
->read(event
);
8651 perf_sample_data_init(&data
, 0, event
->hw
.last_period
);
8652 regs
= get_irq_regs();
8654 if (regs
&& !perf_exclude_event(event
, regs
)) {
8655 if (!(event
->attr
.exclude_idle
&& is_idle_task(current
)))
8656 if (__perf_event_overflow(event
, 1, &data
, regs
))
8657 ret
= HRTIMER_NORESTART
;
8660 period
= max_t(u64
, 10000, event
->hw
.sample_period
);
8661 hrtimer_forward_now(hrtimer
, ns_to_ktime(period
));
8666 static void perf_swevent_start_hrtimer(struct perf_event
*event
)
8668 struct hw_perf_event
*hwc
= &event
->hw
;
8671 if (!is_sampling_event(event
))
8674 period
= local64_read(&hwc
->period_left
);
8679 local64_set(&hwc
->period_left
, 0);
8681 period
= max_t(u64
, 10000, hwc
->sample_period
);
8683 hrtimer_start(&hwc
->hrtimer
, ns_to_ktime(period
),
8684 HRTIMER_MODE_REL_PINNED
);
8687 static void perf_swevent_cancel_hrtimer(struct perf_event
*event
)
8689 struct hw_perf_event
*hwc
= &event
->hw
;
8691 if (is_sampling_event(event
)) {
8692 ktime_t remaining
= hrtimer_get_remaining(&hwc
->hrtimer
);
8693 local64_set(&hwc
->period_left
, ktime_to_ns(remaining
));
8695 hrtimer_cancel(&hwc
->hrtimer
);
8699 static void perf_swevent_init_hrtimer(struct perf_event
*event
)
8701 struct hw_perf_event
*hwc
= &event
->hw
;
8703 if (!is_sampling_event(event
))
8706 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
8707 hwc
->hrtimer
.function
= perf_swevent_hrtimer
;
8710 * Since hrtimers have a fixed rate, we can do a static freq->period
8711 * mapping and avoid the whole period adjust feedback stuff.
8713 if (event
->attr
.freq
) {
8714 long freq
= event
->attr
.sample_freq
;
8716 event
->attr
.sample_period
= NSEC_PER_SEC
/ freq
;
8717 hwc
->sample_period
= event
->attr
.sample_period
;
8718 local64_set(&hwc
->period_left
, hwc
->sample_period
);
8719 hwc
->last_period
= hwc
->sample_period
;
8720 event
->attr
.freq
= 0;
8725 * Software event: cpu wall time clock
8728 static void cpu_clock_event_update(struct perf_event
*event
)
8733 now
= local_clock();
8734 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
8735 local64_add(now
- prev
, &event
->count
);
8738 static void cpu_clock_event_start(struct perf_event
*event
, int flags
)
8740 local64_set(&event
->hw
.prev_count
, local_clock());
8741 perf_swevent_start_hrtimer(event
);
8744 static void cpu_clock_event_stop(struct perf_event
*event
, int flags
)
8746 perf_swevent_cancel_hrtimer(event
);
8747 cpu_clock_event_update(event
);
8750 static int cpu_clock_event_add(struct perf_event
*event
, int flags
)
8752 if (flags
& PERF_EF_START
)
8753 cpu_clock_event_start(event
, flags
);
8754 perf_event_update_userpage(event
);
8759 static void cpu_clock_event_del(struct perf_event
*event
, int flags
)
8761 cpu_clock_event_stop(event
, flags
);
8764 static void cpu_clock_event_read(struct perf_event
*event
)
8766 cpu_clock_event_update(event
);
8769 static int cpu_clock_event_init(struct perf_event
*event
)
8771 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
8774 if (event
->attr
.config
!= PERF_COUNT_SW_CPU_CLOCK
)
8778 * no branch sampling for software events
8780 if (has_branch_stack(event
))
8783 perf_swevent_init_hrtimer(event
);
8788 static struct pmu perf_cpu_clock
= {
8789 .task_ctx_nr
= perf_sw_context
,
8791 .capabilities
= PERF_PMU_CAP_NO_NMI
,
8793 .event_init
= cpu_clock_event_init
,
8794 .add
= cpu_clock_event_add
,
8795 .del
= cpu_clock_event_del
,
8796 .start
= cpu_clock_event_start
,
8797 .stop
= cpu_clock_event_stop
,
8798 .read
= cpu_clock_event_read
,
8802 * Software event: task time clock
8805 static void task_clock_event_update(struct perf_event
*event
, u64 now
)
8810 prev
= local64_xchg(&event
->hw
.prev_count
, now
);
8812 local64_add(delta
, &event
->count
);
8815 static void task_clock_event_start(struct perf_event
*event
, int flags
)
8817 local64_set(&event
->hw
.prev_count
, event
->ctx
->time
);
8818 perf_swevent_start_hrtimer(event
);
8821 static void task_clock_event_stop(struct perf_event
*event
, int flags
)
8823 perf_swevent_cancel_hrtimer(event
);
8824 task_clock_event_update(event
, event
->ctx
->time
);
8827 static int task_clock_event_add(struct perf_event
*event
, int flags
)
8829 if (flags
& PERF_EF_START
)
8830 task_clock_event_start(event
, flags
);
8831 perf_event_update_userpage(event
);
8836 static void task_clock_event_del(struct perf_event
*event
, int flags
)
8838 task_clock_event_stop(event
, PERF_EF_UPDATE
);
8841 static void task_clock_event_read(struct perf_event
*event
)
8843 u64 now
= perf_clock();
8844 u64 delta
= now
- event
->ctx
->timestamp
;
8845 u64 time
= event
->ctx
->time
+ delta
;
8847 task_clock_event_update(event
, time
);
8850 static int task_clock_event_init(struct perf_event
*event
)
8852 if (event
->attr
.type
!= PERF_TYPE_SOFTWARE
)
8855 if (event
->attr
.config
!= PERF_COUNT_SW_TASK_CLOCK
)
8859 * no branch sampling for software events
8861 if (has_branch_stack(event
))
8864 perf_swevent_init_hrtimer(event
);
8869 static struct pmu perf_task_clock
= {
8870 .task_ctx_nr
= perf_sw_context
,
8872 .capabilities
= PERF_PMU_CAP_NO_NMI
,
8874 .event_init
= task_clock_event_init
,
8875 .add
= task_clock_event_add
,
8876 .del
= task_clock_event_del
,
8877 .start
= task_clock_event_start
,
8878 .stop
= task_clock_event_stop
,
8879 .read
= task_clock_event_read
,
8882 static void perf_pmu_nop_void(struct pmu
*pmu
)
8886 static void perf_pmu_nop_txn(struct pmu
*pmu
, unsigned int flags
)
8890 static int perf_pmu_nop_int(struct pmu
*pmu
)
8895 static DEFINE_PER_CPU(unsigned int, nop_txn_flags
);
8897 static void perf_pmu_start_txn(struct pmu
*pmu
, unsigned int flags
)
8899 __this_cpu_write(nop_txn_flags
, flags
);
8901 if (flags
& ~PERF_PMU_TXN_ADD
)
8904 perf_pmu_disable(pmu
);
8907 static int perf_pmu_commit_txn(struct pmu
*pmu
)
8909 unsigned int flags
= __this_cpu_read(nop_txn_flags
);
8911 __this_cpu_write(nop_txn_flags
, 0);
8913 if (flags
& ~PERF_PMU_TXN_ADD
)
8916 perf_pmu_enable(pmu
);
8920 static void perf_pmu_cancel_txn(struct pmu
*pmu
)
8922 unsigned int flags
= __this_cpu_read(nop_txn_flags
);
8924 __this_cpu_write(nop_txn_flags
, 0);
8926 if (flags
& ~PERF_PMU_TXN_ADD
)
8929 perf_pmu_enable(pmu
);
8932 static int perf_event_idx_default(struct perf_event
*event
)
8938 * Ensures all contexts with the same task_ctx_nr have the same
8939 * pmu_cpu_context too.
8941 static struct perf_cpu_context __percpu
*find_pmu_context(int ctxn
)
8948 list_for_each_entry(pmu
, &pmus
, entry
) {
8949 if (pmu
->task_ctx_nr
== ctxn
)
8950 return pmu
->pmu_cpu_context
;
8956 static void free_pmu_context(struct pmu
*pmu
)
8959 * Static contexts such as perf_sw_context have a global lifetime
8960 * and may be shared between different PMUs. Avoid freeing them
8961 * when a single PMU is going away.
8963 if (pmu
->task_ctx_nr
> perf_invalid_context
)
8966 mutex_lock(&pmus_lock
);
8967 free_percpu(pmu
->pmu_cpu_context
);
8968 mutex_unlock(&pmus_lock
);
8972 * Let userspace know that this PMU supports address range filtering:
8974 static ssize_t
nr_addr_filters_show(struct device
*dev
,
8975 struct device_attribute
*attr
,
8978 struct pmu
*pmu
= dev_get_drvdata(dev
);
8980 return snprintf(page
, PAGE_SIZE
- 1, "%d\n", pmu
->nr_addr_filters
);
8982 DEVICE_ATTR_RO(nr_addr_filters
);
8984 static struct idr pmu_idr
;
8987 type_show(struct device
*dev
, struct device_attribute
*attr
, char *page
)
8989 struct pmu
*pmu
= dev_get_drvdata(dev
);
8991 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->type
);
8993 static DEVICE_ATTR_RO(type
);
8996 perf_event_mux_interval_ms_show(struct device
*dev
,
8997 struct device_attribute
*attr
,
9000 struct pmu
*pmu
= dev_get_drvdata(dev
);
9002 return snprintf(page
, PAGE_SIZE
-1, "%d\n", pmu
->hrtimer_interval_ms
);
9005 static DEFINE_MUTEX(mux_interval_mutex
);
9008 perf_event_mux_interval_ms_store(struct device
*dev
,
9009 struct device_attribute
*attr
,
9010 const char *buf
, size_t count
)
9012 struct pmu
*pmu
= dev_get_drvdata(dev
);
9013 int timer
, cpu
, ret
;
9015 ret
= kstrtoint(buf
, 0, &timer
);
9022 /* same value, noting to do */
9023 if (timer
== pmu
->hrtimer_interval_ms
)
9026 mutex_lock(&mux_interval_mutex
);
9027 pmu
->hrtimer_interval_ms
= timer
;
9029 /* update all cpuctx for this PMU */
9031 for_each_online_cpu(cpu
) {
9032 struct perf_cpu_context
*cpuctx
;
9033 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
9034 cpuctx
->hrtimer_interval
= ns_to_ktime(NSEC_PER_MSEC
* timer
);
9036 cpu_function_call(cpu
,
9037 (remote_function_f
)perf_mux_hrtimer_restart
, cpuctx
);
9040 mutex_unlock(&mux_interval_mutex
);
9044 static DEVICE_ATTR_RW(perf_event_mux_interval_ms
);
9046 static struct attribute
*pmu_dev_attrs
[] = {
9047 &dev_attr_type
.attr
,
9048 &dev_attr_perf_event_mux_interval_ms
.attr
,
9051 ATTRIBUTE_GROUPS(pmu_dev
);
9053 static int pmu_bus_running
;
9054 static struct bus_type pmu_bus
= {
9055 .name
= "event_source",
9056 .dev_groups
= pmu_dev_groups
,
9059 static void pmu_dev_release(struct device
*dev
)
9064 static int pmu_dev_alloc(struct pmu
*pmu
)
9068 pmu
->dev
= kzalloc(sizeof(struct device
), GFP_KERNEL
);
9072 pmu
->dev
->groups
= pmu
->attr_groups
;
9073 device_initialize(pmu
->dev
);
9074 ret
= dev_set_name(pmu
->dev
, "%s", pmu
->name
);
9078 dev_set_drvdata(pmu
->dev
, pmu
);
9079 pmu
->dev
->bus
= &pmu_bus
;
9080 pmu
->dev
->release
= pmu_dev_release
;
9081 ret
= device_add(pmu
->dev
);
9085 /* For PMUs with address filters, throw in an extra attribute: */
9086 if (pmu
->nr_addr_filters
)
9087 ret
= device_create_file(pmu
->dev
, &dev_attr_nr_addr_filters
);
9096 device_del(pmu
->dev
);
9099 put_device(pmu
->dev
);
9103 static struct lock_class_key cpuctx_mutex
;
9104 static struct lock_class_key cpuctx_lock
;
9106 int perf_pmu_register(struct pmu
*pmu
, const char *name
, int type
)
9110 mutex_lock(&pmus_lock
);
9112 pmu
->pmu_disable_count
= alloc_percpu(int);
9113 if (!pmu
->pmu_disable_count
)
9122 type
= idr_alloc(&pmu_idr
, pmu
, PERF_TYPE_MAX
, 0, GFP_KERNEL
);
9130 if (pmu_bus_running
) {
9131 ret
= pmu_dev_alloc(pmu
);
9137 if (pmu
->task_ctx_nr
== perf_hw_context
) {
9138 static int hw_context_taken
= 0;
9141 * Other than systems with heterogeneous CPUs, it never makes
9142 * sense for two PMUs to share perf_hw_context. PMUs which are
9143 * uncore must use perf_invalid_context.
9145 if (WARN_ON_ONCE(hw_context_taken
&&
9146 !(pmu
->capabilities
& PERF_PMU_CAP_HETEROGENEOUS_CPUS
)))
9147 pmu
->task_ctx_nr
= perf_invalid_context
;
9149 hw_context_taken
= 1;
9152 pmu
->pmu_cpu_context
= find_pmu_context(pmu
->task_ctx_nr
);
9153 if (pmu
->pmu_cpu_context
)
9154 goto got_cpu_context
;
9157 pmu
->pmu_cpu_context
= alloc_percpu(struct perf_cpu_context
);
9158 if (!pmu
->pmu_cpu_context
)
9161 for_each_possible_cpu(cpu
) {
9162 struct perf_cpu_context
*cpuctx
;
9164 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
9165 __perf_event_init_context(&cpuctx
->ctx
);
9166 lockdep_set_class(&cpuctx
->ctx
.mutex
, &cpuctx_mutex
);
9167 lockdep_set_class(&cpuctx
->ctx
.lock
, &cpuctx_lock
);
9168 cpuctx
->ctx
.pmu
= pmu
;
9169 cpuctx
->online
= cpumask_test_cpu(cpu
, perf_online_mask
);
9171 __perf_mux_hrtimer_init(cpuctx
, cpu
);
9175 if (!pmu
->start_txn
) {
9176 if (pmu
->pmu_enable
) {
9178 * If we have pmu_enable/pmu_disable calls, install
9179 * transaction stubs that use that to try and batch
9180 * hardware accesses.
9182 pmu
->start_txn
= perf_pmu_start_txn
;
9183 pmu
->commit_txn
= perf_pmu_commit_txn
;
9184 pmu
->cancel_txn
= perf_pmu_cancel_txn
;
9186 pmu
->start_txn
= perf_pmu_nop_txn
;
9187 pmu
->commit_txn
= perf_pmu_nop_int
;
9188 pmu
->cancel_txn
= perf_pmu_nop_void
;
9192 if (!pmu
->pmu_enable
) {
9193 pmu
->pmu_enable
= perf_pmu_nop_void
;
9194 pmu
->pmu_disable
= perf_pmu_nop_void
;
9197 if (!pmu
->event_idx
)
9198 pmu
->event_idx
= perf_event_idx_default
;
9200 list_add_rcu(&pmu
->entry
, &pmus
);
9201 atomic_set(&pmu
->exclusive_cnt
, 0);
9204 mutex_unlock(&pmus_lock
);
9209 device_del(pmu
->dev
);
9210 put_device(pmu
->dev
);
9213 if (pmu
->type
>= PERF_TYPE_MAX
)
9214 idr_remove(&pmu_idr
, pmu
->type
);
9217 free_percpu(pmu
->pmu_disable_count
);
9220 EXPORT_SYMBOL_GPL(perf_pmu_register
);
9222 void perf_pmu_unregister(struct pmu
*pmu
)
9226 mutex_lock(&pmus_lock
);
9227 remove_device
= pmu_bus_running
;
9228 list_del_rcu(&pmu
->entry
);
9229 mutex_unlock(&pmus_lock
);
9232 * We dereference the pmu list under both SRCU and regular RCU, so
9233 * synchronize against both of those.
9235 synchronize_srcu(&pmus_srcu
);
9238 free_percpu(pmu
->pmu_disable_count
);
9239 if (pmu
->type
>= PERF_TYPE_MAX
)
9240 idr_remove(&pmu_idr
, pmu
->type
);
9241 if (remove_device
) {
9242 if (pmu
->nr_addr_filters
)
9243 device_remove_file(pmu
->dev
, &dev_attr_nr_addr_filters
);
9244 device_del(pmu
->dev
);
9245 put_device(pmu
->dev
);
9247 free_pmu_context(pmu
);
9249 EXPORT_SYMBOL_GPL(perf_pmu_unregister
);
9251 static int perf_try_init_event(struct pmu
*pmu
, struct perf_event
*event
)
9253 struct perf_event_context
*ctx
= NULL
;
9256 if (!try_module_get(pmu
->module
))
9259 if (event
->group_leader
!= event
) {
9261 * This ctx->mutex can nest when we're called through
9262 * inheritance. See the perf_event_ctx_lock_nested() comment.
9264 ctx
= perf_event_ctx_lock_nested(event
->group_leader
,
9265 SINGLE_DEPTH_NESTING
);
9270 ret
= pmu
->event_init(event
);
9273 perf_event_ctx_unlock(event
->group_leader
, ctx
);
9276 module_put(pmu
->module
);
9281 static struct pmu
*perf_init_event(struct perf_event
*event
)
9287 idx
= srcu_read_lock(&pmus_srcu
);
9289 /* Try parent's PMU first: */
9290 if (event
->parent
&& event
->parent
->pmu
) {
9291 pmu
= event
->parent
->pmu
;
9292 ret
= perf_try_init_event(pmu
, event
);
9298 pmu
= idr_find(&pmu_idr
, event
->attr
.type
);
9301 ret
= perf_try_init_event(pmu
, event
);
9307 list_for_each_entry_rcu(pmu
, &pmus
, entry
) {
9308 ret
= perf_try_init_event(pmu
, event
);
9312 if (ret
!= -ENOENT
) {
9317 pmu
= ERR_PTR(-ENOENT
);
9319 srcu_read_unlock(&pmus_srcu
, idx
);
9324 static void attach_sb_event(struct perf_event
*event
)
9326 struct pmu_event_list
*pel
= per_cpu_ptr(&pmu_sb_events
, event
->cpu
);
9328 raw_spin_lock(&pel
->lock
);
9329 list_add_rcu(&event
->sb_list
, &pel
->list
);
9330 raw_spin_unlock(&pel
->lock
);
9334 * We keep a list of all !task (and therefore per-cpu) events
9335 * that need to receive side-band records.
9337 * This avoids having to scan all the various PMU per-cpu contexts
9340 static void account_pmu_sb_event(struct perf_event
*event
)
9342 if (is_sb_event(event
))
9343 attach_sb_event(event
);
9346 static void account_event_cpu(struct perf_event
*event
, int cpu
)
9351 if (is_cgroup_event(event
))
9352 atomic_inc(&per_cpu(perf_cgroup_events
, cpu
));
9355 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9356 static void account_freq_event_nohz(void)
9358 #ifdef CONFIG_NO_HZ_FULL
9359 /* Lock so we don't race with concurrent unaccount */
9360 spin_lock(&nr_freq_lock
);
9361 if (atomic_inc_return(&nr_freq_events
) == 1)
9362 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS
);
9363 spin_unlock(&nr_freq_lock
);
9367 static void account_freq_event(void)
9369 if (tick_nohz_full_enabled())
9370 account_freq_event_nohz();
9372 atomic_inc(&nr_freq_events
);
9376 static void account_event(struct perf_event
*event
)
9383 if (event
->attach_state
& PERF_ATTACH_TASK
)
9385 if (event
->attr
.mmap
|| event
->attr
.mmap_data
)
9386 atomic_inc(&nr_mmap_events
);
9387 if (event
->attr
.comm
)
9388 atomic_inc(&nr_comm_events
);
9389 if (event
->attr
.namespaces
)
9390 atomic_inc(&nr_namespaces_events
);
9391 if (event
->attr
.task
)
9392 atomic_inc(&nr_task_events
);
9393 if (event
->attr
.freq
)
9394 account_freq_event();
9395 if (event
->attr
.context_switch
) {
9396 atomic_inc(&nr_switch_events
);
9399 if (has_branch_stack(event
))
9401 if (is_cgroup_event(event
))
9405 if (atomic_inc_not_zero(&perf_sched_count
))
9408 mutex_lock(&perf_sched_mutex
);
9409 if (!atomic_read(&perf_sched_count
)) {
9410 static_branch_enable(&perf_sched_events
);
9412 * Guarantee that all CPUs observe they key change and
9413 * call the perf scheduling hooks before proceeding to
9414 * install events that need them.
9416 synchronize_sched();
9419 * Now that we have waited for the sync_sched(), allow further
9420 * increments to by-pass the mutex.
9422 atomic_inc(&perf_sched_count
);
9423 mutex_unlock(&perf_sched_mutex
);
9427 account_event_cpu(event
, event
->cpu
);
9429 account_pmu_sb_event(event
);
9433 * Allocate and initialize a event structure
9435 static struct perf_event
*
9436 perf_event_alloc(struct perf_event_attr
*attr
, int cpu
,
9437 struct task_struct
*task
,
9438 struct perf_event
*group_leader
,
9439 struct perf_event
*parent_event
,
9440 perf_overflow_handler_t overflow_handler
,
9441 void *context
, int cgroup_fd
)
9444 struct perf_event
*event
;
9445 struct hw_perf_event
*hwc
;
9448 if ((unsigned)cpu
>= nr_cpu_ids
) {
9449 if (!task
|| cpu
!= -1)
9450 return ERR_PTR(-EINVAL
);
9453 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
9455 return ERR_PTR(-ENOMEM
);
9458 * Single events are their own group leaders, with an
9459 * empty sibling list:
9462 group_leader
= event
;
9464 mutex_init(&event
->child_mutex
);
9465 INIT_LIST_HEAD(&event
->child_list
);
9467 INIT_LIST_HEAD(&event
->group_entry
);
9468 INIT_LIST_HEAD(&event
->event_entry
);
9469 INIT_LIST_HEAD(&event
->sibling_list
);
9470 INIT_LIST_HEAD(&event
->rb_entry
);
9471 INIT_LIST_HEAD(&event
->active_entry
);
9472 INIT_LIST_HEAD(&event
->addr_filters
.list
);
9473 INIT_HLIST_NODE(&event
->hlist_entry
);
9476 init_waitqueue_head(&event
->waitq
);
9477 init_irq_work(&event
->pending
, perf_pending_event
);
9479 mutex_init(&event
->mmap_mutex
);
9480 raw_spin_lock_init(&event
->addr_filters
.lock
);
9482 atomic_long_set(&event
->refcount
, 1);
9484 event
->attr
= *attr
;
9485 event
->group_leader
= group_leader
;
9489 event
->parent
= parent_event
;
9491 event
->ns
= get_pid_ns(task_active_pid_ns(current
));
9492 event
->id
= atomic64_inc_return(&perf_event_id
);
9494 event
->state
= PERF_EVENT_STATE_INACTIVE
;
9497 event
->attach_state
= PERF_ATTACH_TASK
;
9499 * XXX pmu::event_init needs to know what task to account to
9500 * and we cannot use the ctx information because we need the
9501 * pmu before we get a ctx.
9503 event
->hw
.target
= task
;
9506 event
->clock
= &local_clock
;
9508 event
->clock
= parent_event
->clock
;
9510 if (!overflow_handler
&& parent_event
) {
9511 overflow_handler
= parent_event
->overflow_handler
;
9512 context
= parent_event
->overflow_handler_context
;
9513 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9514 if (overflow_handler
== bpf_overflow_handler
) {
9515 struct bpf_prog
*prog
= bpf_prog_inc(parent_event
->prog
);
9518 err
= PTR_ERR(prog
);
9522 event
->orig_overflow_handler
=
9523 parent_event
->orig_overflow_handler
;
9528 if (overflow_handler
) {
9529 event
->overflow_handler
= overflow_handler
;
9530 event
->overflow_handler_context
= context
;
9531 } else if (is_write_backward(event
)){
9532 event
->overflow_handler
= perf_event_output_backward
;
9533 event
->overflow_handler_context
= NULL
;
9535 event
->overflow_handler
= perf_event_output_forward
;
9536 event
->overflow_handler_context
= NULL
;
9539 perf_event__state_init(event
);
9544 hwc
->sample_period
= attr
->sample_period
;
9545 if (attr
->freq
&& attr
->sample_freq
)
9546 hwc
->sample_period
= 1;
9547 hwc
->last_period
= hwc
->sample_period
;
9549 local64_set(&hwc
->period_left
, hwc
->sample_period
);
9552 * We currently do not support PERF_SAMPLE_READ on inherited events.
9553 * See perf_output_read().
9555 if (attr
->inherit
&& (attr
->sample_type
& PERF_SAMPLE_READ
))
9558 if (!has_branch_stack(event
))
9559 event
->attr
.branch_sample_type
= 0;
9561 if (cgroup_fd
!= -1) {
9562 err
= perf_cgroup_connect(cgroup_fd
, event
, attr
, group_leader
);
9567 pmu
= perf_init_event(event
);
9573 err
= exclusive_event_init(event
);
9577 if (has_addr_filter(event
)) {
9578 event
->addr_filters_offs
= kcalloc(pmu
->nr_addr_filters
,
9579 sizeof(unsigned long),
9581 if (!event
->addr_filters_offs
) {
9586 /* force hw sync on the address filters */
9587 event
->addr_filters_gen
= 1;
9590 if (!event
->parent
) {
9591 if (event
->attr
.sample_type
& PERF_SAMPLE_CALLCHAIN
) {
9592 err
= get_callchain_buffers(attr
->sample_max_stack
);
9594 goto err_addr_filters
;
9598 /* symmetric to unaccount_event() in _free_event() */
9599 account_event(event
);
9604 kfree(event
->addr_filters_offs
);
9607 exclusive_event_destroy(event
);
9611 event
->destroy(event
);
9612 module_put(pmu
->module
);
9614 if (is_cgroup_event(event
))
9615 perf_detach_cgroup(event
);
9617 put_pid_ns(event
->ns
);
9620 return ERR_PTR(err
);
9623 static int perf_copy_attr(struct perf_event_attr __user
*uattr
,
9624 struct perf_event_attr
*attr
)
9629 if (!access_ok(VERIFY_WRITE
, uattr
, PERF_ATTR_SIZE_VER0
))
9633 * zero the full structure, so that a short copy will be nice.
9635 memset(attr
, 0, sizeof(*attr
));
9637 ret
= get_user(size
, &uattr
->size
);
9641 if (size
> PAGE_SIZE
) /* silly large */
9644 if (!size
) /* abi compat */
9645 size
= PERF_ATTR_SIZE_VER0
;
9647 if (size
< PERF_ATTR_SIZE_VER0
)
9651 * If we're handed a bigger struct than we know of,
9652 * ensure all the unknown bits are 0 - i.e. new
9653 * user-space does not rely on any kernel feature
9654 * extensions we dont know about yet.
9656 if (size
> sizeof(*attr
)) {
9657 unsigned char __user
*addr
;
9658 unsigned char __user
*end
;
9661 addr
= (void __user
*)uattr
+ sizeof(*attr
);
9662 end
= (void __user
*)uattr
+ size
;
9664 for (; addr
< end
; addr
++) {
9665 ret
= get_user(val
, addr
);
9671 size
= sizeof(*attr
);
9674 ret
= copy_from_user(attr
, uattr
, size
);
9680 if (attr
->__reserved_1
)
9683 if (attr
->sample_type
& ~(PERF_SAMPLE_MAX
-1))
9686 if (attr
->read_format
& ~(PERF_FORMAT_MAX
-1))
9689 if (attr
->sample_type
& PERF_SAMPLE_BRANCH_STACK
) {
9690 u64 mask
= attr
->branch_sample_type
;
9692 /* only using defined bits */
9693 if (mask
& ~(PERF_SAMPLE_BRANCH_MAX
-1))
9696 /* at least one branch bit must be set */
9697 if (!(mask
& ~PERF_SAMPLE_BRANCH_PLM_ALL
))
9700 /* propagate priv level, when not set for branch */
9701 if (!(mask
& PERF_SAMPLE_BRANCH_PLM_ALL
)) {
9703 /* exclude_kernel checked on syscall entry */
9704 if (!attr
->exclude_kernel
)
9705 mask
|= PERF_SAMPLE_BRANCH_KERNEL
;
9707 if (!attr
->exclude_user
)
9708 mask
|= PERF_SAMPLE_BRANCH_USER
;
9710 if (!attr
->exclude_hv
)
9711 mask
|= PERF_SAMPLE_BRANCH_HV
;
9713 * adjust user setting (for HW filter setup)
9715 attr
->branch_sample_type
= mask
;
9717 /* privileged levels capture (kernel, hv): check permissions */
9718 if ((mask
& PERF_SAMPLE_BRANCH_PERM_PLM
)
9719 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
9723 if (attr
->sample_type
& PERF_SAMPLE_REGS_USER
) {
9724 ret
= perf_reg_validate(attr
->sample_regs_user
);
9729 if (attr
->sample_type
& PERF_SAMPLE_STACK_USER
) {
9730 if (!arch_perf_have_user_stack_dump())
9734 * We have __u32 type for the size, but so far
9735 * we can only use __u16 as maximum due to the
9736 * __u16 sample size limit.
9738 if (attr
->sample_stack_user
>= USHRT_MAX
)
9740 else if (!IS_ALIGNED(attr
->sample_stack_user
, sizeof(u64
)))
9744 if (attr
->sample_type
& PERF_SAMPLE_REGS_INTR
)
9745 ret
= perf_reg_validate(attr
->sample_regs_intr
);
9750 put_user(sizeof(*attr
), &uattr
->size
);
9756 perf_event_set_output(struct perf_event
*event
, struct perf_event
*output_event
)
9758 struct ring_buffer
*rb
= NULL
;
9764 /* don't allow circular references */
9765 if (event
== output_event
)
9769 * Don't allow cross-cpu buffers
9771 if (output_event
->cpu
!= event
->cpu
)
9775 * If its not a per-cpu rb, it must be the same task.
9777 if (output_event
->cpu
== -1 && output_event
->ctx
!= event
->ctx
)
9781 * Mixing clocks in the same buffer is trouble you don't need.
9783 if (output_event
->clock
!= event
->clock
)
9787 * Either writing ring buffer from beginning or from end.
9788 * Mixing is not allowed.
9790 if (is_write_backward(output_event
) != is_write_backward(event
))
9794 * If both events generate aux data, they must be on the same PMU
9796 if (has_aux(event
) && has_aux(output_event
) &&
9797 event
->pmu
!= output_event
->pmu
)
9801 mutex_lock(&event
->mmap_mutex
);
9802 /* Can't redirect output if we've got an active mmap() */
9803 if (atomic_read(&event
->mmap_count
))
9807 /* get the rb we want to redirect to */
9808 rb
= ring_buffer_get(output_event
);
9813 ring_buffer_attach(event
, rb
);
9817 mutex_unlock(&event
->mmap_mutex
);
9823 static void mutex_lock_double(struct mutex
*a
, struct mutex
*b
)
9829 mutex_lock_nested(b
, SINGLE_DEPTH_NESTING
);
9832 static int perf_event_set_clock(struct perf_event
*event
, clockid_t clk_id
)
9834 bool nmi_safe
= false;
9837 case CLOCK_MONOTONIC
:
9838 event
->clock
= &ktime_get_mono_fast_ns
;
9842 case CLOCK_MONOTONIC_RAW
:
9843 event
->clock
= &ktime_get_raw_fast_ns
;
9847 case CLOCK_REALTIME
:
9848 event
->clock
= &ktime_get_real_ns
;
9851 case CLOCK_BOOTTIME
:
9852 event
->clock
= &ktime_get_boot_ns
;
9856 event
->clock
= &ktime_get_tai_ns
;
9863 if (!nmi_safe
&& !(event
->pmu
->capabilities
& PERF_PMU_CAP_NO_NMI
))
9870 * Variation on perf_event_ctx_lock_nested(), except we take two context
9873 static struct perf_event_context
*
9874 __perf_event_ctx_lock_double(struct perf_event
*group_leader
,
9875 struct perf_event_context
*ctx
)
9877 struct perf_event_context
*gctx
;
9881 gctx
= READ_ONCE(group_leader
->ctx
);
9882 if (!atomic_inc_not_zero(&gctx
->refcount
)) {
9888 mutex_lock_double(&gctx
->mutex
, &ctx
->mutex
);
9890 if (group_leader
->ctx
!= gctx
) {
9891 mutex_unlock(&ctx
->mutex
);
9892 mutex_unlock(&gctx
->mutex
);
9901 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9903 * @attr_uptr: event_id type attributes for monitoring/sampling
9906 * @group_fd: group leader event fd
9908 SYSCALL_DEFINE5(perf_event_open
,
9909 struct perf_event_attr __user
*, attr_uptr
,
9910 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
9912 struct perf_event
*group_leader
= NULL
, *output_event
= NULL
;
9913 struct perf_event
*event
, *sibling
;
9914 struct perf_event_attr attr
;
9915 struct perf_event_context
*ctx
, *uninitialized_var(gctx
);
9916 struct file
*event_file
= NULL
;
9917 struct fd group
= {NULL
, 0};
9918 struct task_struct
*task
= NULL
;
9923 int f_flags
= O_RDWR
;
9926 /* for future expandability... */
9927 if (flags
& ~PERF_FLAG_ALL
)
9930 err
= perf_copy_attr(attr_uptr
, &attr
);
9934 if (!attr
.exclude_kernel
) {
9935 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
9939 if (attr
.namespaces
) {
9940 if (!capable(CAP_SYS_ADMIN
))
9945 if (attr
.sample_freq
> sysctl_perf_event_sample_rate
)
9948 if (attr
.sample_period
& (1ULL << 63))
9952 /* Only privileged users can get physical addresses */
9953 if ((attr
.sample_type
& PERF_SAMPLE_PHYS_ADDR
) &&
9954 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN
))
9957 if (!attr
.sample_max_stack
)
9958 attr
.sample_max_stack
= sysctl_perf_event_max_stack
;
9961 * In cgroup mode, the pid argument is used to pass the fd
9962 * opened to the cgroup directory in cgroupfs. The cpu argument
9963 * designates the cpu on which to monitor threads from that
9966 if ((flags
& PERF_FLAG_PID_CGROUP
) && (pid
== -1 || cpu
== -1))
9969 if (flags
& PERF_FLAG_FD_CLOEXEC
)
9970 f_flags
|= O_CLOEXEC
;
9972 event_fd
= get_unused_fd_flags(f_flags
);
9976 if (group_fd
!= -1) {
9977 err
= perf_fget_light(group_fd
, &group
);
9980 group_leader
= group
.file
->private_data
;
9981 if (flags
& PERF_FLAG_FD_OUTPUT
)
9982 output_event
= group_leader
;
9983 if (flags
& PERF_FLAG_FD_NO_GROUP
)
9984 group_leader
= NULL
;
9987 if (pid
!= -1 && !(flags
& PERF_FLAG_PID_CGROUP
)) {
9988 task
= find_lively_task_by_vpid(pid
);
9990 err
= PTR_ERR(task
);
9995 if (task
&& group_leader
&&
9996 group_leader
->attr
.inherit
!= attr
.inherit
) {
10002 err
= mutex_lock_interruptible(&task
->signal
->cred_guard_mutex
);
10007 * Reuse ptrace permission checks for now.
10009 * We must hold cred_guard_mutex across this and any potential
10010 * perf_install_in_context() call for this new event to
10011 * serialize against exec() altering our credentials (and the
10012 * perf_event_exit_task() that could imply).
10015 if (!ptrace_may_access(task
, PTRACE_MODE_READ_REALCREDS
))
10019 if (flags
& PERF_FLAG_PID_CGROUP
)
10022 event
= perf_event_alloc(&attr
, cpu
, task
, group_leader
, NULL
,
10023 NULL
, NULL
, cgroup_fd
);
10024 if (IS_ERR(event
)) {
10025 err
= PTR_ERR(event
);
10029 if (is_sampling_event(event
)) {
10030 if (event
->pmu
->capabilities
& PERF_PMU_CAP_NO_INTERRUPT
) {
10037 * Special case software events and allow them to be part of
10038 * any hardware group.
10042 if (attr
.use_clockid
) {
10043 err
= perf_event_set_clock(event
, attr
.clockid
);
10048 if (pmu
->task_ctx_nr
== perf_sw_context
)
10049 event
->event_caps
|= PERF_EV_CAP_SOFTWARE
;
10051 if (group_leader
&&
10052 (is_software_event(event
) != is_software_event(group_leader
))) {
10053 if (is_software_event(event
)) {
10055 * If event and group_leader are not both a software
10056 * event, and event is, then group leader is not.
10058 * Allow the addition of software events to !software
10059 * groups, this is safe because software events never
10060 * fail to schedule.
10062 pmu
= group_leader
->pmu
;
10063 } else if (is_software_event(group_leader
) &&
10064 (group_leader
->group_caps
& PERF_EV_CAP_SOFTWARE
)) {
10066 * In case the group is a pure software group, and we
10067 * try to add a hardware event, move the whole group to
10068 * the hardware context.
10075 * Get the target context (task or percpu):
10077 ctx
= find_get_context(pmu
, task
, event
);
10079 err
= PTR_ERR(ctx
);
10083 if ((pmu
->capabilities
& PERF_PMU_CAP_EXCLUSIVE
) && group_leader
) {
10089 * Look up the group leader (we will attach this event to it):
10091 if (group_leader
) {
10095 * Do not allow a recursive hierarchy (this new sibling
10096 * becoming part of another group-sibling):
10098 if (group_leader
->group_leader
!= group_leader
)
10101 /* All events in a group should have the same clock */
10102 if (group_leader
->clock
!= event
->clock
)
10106 * Make sure we're both events for the same CPU;
10107 * grouping events for different CPUs is broken; since
10108 * you can never concurrently schedule them anyhow.
10110 if (group_leader
->cpu
!= event
->cpu
)
10114 * Make sure we're both on the same task, or both
10117 if (group_leader
->ctx
->task
!= ctx
->task
)
10121 * Do not allow to attach to a group in a different task
10122 * or CPU context. If we're moving SW events, we'll fix
10123 * this up later, so allow that.
10125 if (!move_group
&& group_leader
->ctx
!= ctx
)
10129 * Only a group leader can be exclusive or pinned
10131 if (attr
.exclusive
|| attr
.pinned
)
10135 if (output_event
) {
10136 err
= perf_event_set_output(event
, output_event
);
10141 event_file
= anon_inode_getfile("[perf_event]", &perf_fops
, event
,
10143 if (IS_ERR(event_file
)) {
10144 err
= PTR_ERR(event_file
);
10150 gctx
= __perf_event_ctx_lock_double(group_leader
, ctx
);
10152 if (gctx
->task
== TASK_TOMBSTONE
) {
10158 * Check if we raced against another sys_perf_event_open() call
10159 * moving the software group underneath us.
10161 if (!(group_leader
->group_caps
& PERF_EV_CAP_SOFTWARE
)) {
10163 * If someone moved the group out from under us, check
10164 * if this new event wound up on the same ctx, if so
10165 * its the regular !move_group case, otherwise fail.
10171 perf_event_ctx_unlock(group_leader
, gctx
);
10176 mutex_lock(&ctx
->mutex
);
10179 if (ctx
->task
== TASK_TOMBSTONE
) {
10184 if (!perf_event_validate_size(event
)) {
10191 * Check if the @cpu we're creating an event for is online.
10193 * We use the perf_cpu_context::ctx::mutex to serialize against
10194 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10196 struct perf_cpu_context
*cpuctx
=
10197 container_of(ctx
, struct perf_cpu_context
, ctx
);
10199 if (!cpuctx
->online
) {
10207 * Must be under the same ctx::mutex as perf_install_in_context(),
10208 * because we need to serialize with concurrent event creation.
10210 if (!exclusive_event_installable(event
, ctx
)) {
10211 /* exclusive and group stuff are assumed mutually exclusive */
10212 WARN_ON_ONCE(move_group
);
10218 WARN_ON_ONCE(ctx
->parent_ctx
);
10221 * This is the point on no return; we cannot fail hereafter. This is
10222 * where we start modifying current state.
10227 * See perf_event_ctx_lock() for comments on the details
10228 * of swizzling perf_event::ctx.
10230 perf_remove_from_context(group_leader
, 0);
10233 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
10235 perf_remove_from_context(sibling
, 0);
10240 * Wait for everybody to stop referencing the events through
10241 * the old lists, before installing it on new lists.
10246 * Install the group siblings before the group leader.
10248 * Because a group leader will try and install the entire group
10249 * (through the sibling list, which is still in-tact), we can
10250 * end up with siblings installed in the wrong context.
10252 * By installing siblings first we NO-OP because they're not
10253 * reachable through the group lists.
10255 list_for_each_entry(sibling
, &group_leader
->sibling_list
,
10257 perf_event__state_init(sibling
);
10258 perf_install_in_context(ctx
, sibling
, sibling
->cpu
);
10263 * Removing from the context ends up with disabled
10264 * event. What we want here is event in the initial
10265 * startup state, ready to be add into new context.
10267 perf_event__state_init(group_leader
);
10268 perf_install_in_context(ctx
, group_leader
, group_leader
->cpu
);
10273 * Precalculate sample_data sizes; do while holding ctx::mutex such
10274 * that we're serialized against further additions and before
10275 * perf_install_in_context() which is the point the event is active and
10276 * can use these values.
10278 perf_event__header_size(event
);
10279 perf_event__id_header_size(event
);
10281 event
->owner
= current
;
10283 perf_install_in_context(ctx
, event
, event
->cpu
);
10284 perf_unpin_context(ctx
);
10287 perf_event_ctx_unlock(group_leader
, gctx
);
10288 mutex_unlock(&ctx
->mutex
);
10291 mutex_unlock(&task
->signal
->cred_guard_mutex
);
10292 put_task_struct(task
);
10295 mutex_lock(¤t
->perf_event_mutex
);
10296 list_add_tail(&event
->owner_entry
, ¤t
->perf_event_list
);
10297 mutex_unlock(¤t
->perf_event_mutex
);
10300 * Drop the reference on the group_event after placing the
10301 * new event on the sibling_list. This ensures destruction
10302 * of the group leader will find the pointer to itself in
10303 * perf_group_detach().
10306 fd_install(event_fd
, event_file
);
10311 perf_event_ctx_unlock(group_leader
, gctx
);
10312 mutex_unlock(&ctx
->mutex
);
10316 perf_unpin_context(ctx
);
10320 * If event_file is set, the fput() above will have called ->release()
10321 * and that will take care of freeing the event.
10327 mutex_unlock(&task
->signal
->cred_guard_mutex
);
10330 put_task_struct(task
);
10334 put_unused_fd(event_fd
);
10339 * perf_event_create_kernel_counter
10341 * @attr: attributes of the counter to create
10342 * @cpu: cpu in which the counter is bound
10343 * @task: task to profile (NULL for percpu)
10345 struct perf_event
*
10346 perf_event_create_kernel_counter(struct perf_event_attr
*attr
, int cpu
,
10347 struct task_struct
*task
,
10348 perf_overflow_handler_t overflow_handler
,
10351 struct perf_event_context
*ctx
;
10352 struct perf_event
*event
;
10356 * Get the target context (task or percpu):
10359 event
= perf_event_alloc(attr
, cpu
, task
, NULL
, NULL
,
10360 overflow_handler
, context
, -1);
10361 if (IS_ERR(event
)) {
10362 err
= PTR_ERR(event
);
10366 /* Mark owner so we could distinguish it from user events. */
10367 event
->owner
= TASK_TOMBSTONE
;
10369 ctx
= find_get_context(event
->pmu
, task
, event
);
10371 err
= PTR_ERR(ctx
);
10375 WARN_ON_ONCE(ctx
->parent_ctx
);
10376 mutex_lock(&ctx
->mutex
);
10377 if (ctx
->task
== TASK_TOMBSTONE
) {
10384 * Check if the @cpu we're creating an event for is online.
10386 * We use the perf_cpu_context::ctx::mutex to serialize against
10387 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10389 struct perf_cpu_context
*cpuctx
=
10390 container_of(ctx
, struct perf_cpu_context
, ctx
);
10391 if (!cpuctx
->online
) {
10397 if (!exclusive_event_installable(event
, ctx
)) {
10402 perf_install_in_context(ctx
, event
, cpu
);
10403 perf_unpin_context(ctx
);
10404 mutex_unlock(&ctx
->mutex
);
10409 mutex_unlock(&ctx
->mutex
);
10410 perf_unpin_context(ctx
);
10415 return ERR_PTR(err
);
10417 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter
);
10419 void perf_pmu_migrate_context(struct pmu
*pmu
, int src_cpu
, int dst_cpu
)
10421 struct perf_event_context
*src_ctx
;
10422 struct perf_event_context
*dst_ctx
;
10423 struct perf_event
*event
, *tmp
;
10426 src_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, src_cpu
)->ctx
;
10427 dst_ctx
= &per_cpu_ptr(pmu
->pmu_cpu_context
, dst_cpu
)->ctx
;
10430 * See perf_event_ctx_lock() for comments on the details
10431 * of swizzling perf_event::ctx.
10433 mutex_lock_double(&src_ctx
->mutex
, &dst_ctx
->mutex
);
10434 list_for_each_entry_safe(event
, tmp
, &src_ctx
->event_list
,
10436 perf_remove_from_context(event
, 0);
10437 unaccount_event_cpu(event
, src_cpu
);
10439 list_add(&event
->migrate_entry
, &events
);
10443 * Wait for the events to quiesce before re-instating them.
10448 * Re-instate events in 2 passes.
10450 * Skip over group leaders and only install siblings on this first
10451 * pass, siblings will not get enabled without a leader, however a
10452 * leader will enable its siblings, even if those are still on the old
10455 list_for_each_entry_safe(event
, tmp
, &events
, migrate_entry
) {
10456 if (event
->group_leader
== event
)
10459 list_del(&event
->migrate_entry
);
10460 if (event
->state
>= PERF_EVENT_STATE_OFF
)
10461 event
->state
= PERF_EVENT_STATE_INACTIVE
;
10462 account_event_cpu(event
, dst_cpu
);
10463 perf_install_in_context(dst_ctx
, event
, dst_cpu
);
10468 * Once all the siblings are setup properly, install the group leaders
10471 list_for_each_entry_safe(event
, tmp
, &events
, migrate_entry
) {
10472 list_del(&event
->migrate_entry
);
10473 if (event
->state
>= PERF_EVENT_STATE_OFF
)
10474 event
->state
= PERF_EVENT_STATE_INACTIVE
;
10475 account_event_cpu(event
, dst_cpu
);
10476 perf_install_in_context(dst_ctx
, event
, dst_cpu
);
10479 mutex_unlock(&dst_ctx
->mutex
);
10480 mutex_unlock(&src_ctx
->mutex
);
10482 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context
);
10484 static void sync_child_event(struct perf_event
*child_event
,
10485 struct task_struct
*child
)
10487 struct perf_event
*parent_event
= child_event
->parent
;
10490 if (child_event
->attr
.inherit_stat
)
10491 perf_event_read_event(child_event
, child
);
10493 child_val
= perf_event_count(child_event
);
10496 * Add back the child's count to the parent's count:
10498 atomic64_add(child_val
, &parent_event
->child_count
);
10499 atomic64_add(child_event
->total_time_enabled
,
10500 &parent_event
->child_total_time_enabled
);
10501 atomic64_add(child_event
->total_time_running
,
10502 &parent_event
->child_total_time_running
);
10506 perf_event_exit_event(struct perf_event
*child_event
,
10507 struct perf_event_context
*child_ctx
,
10508 struct task_struct
*child
)
10510 struct perf_event
*parent_event
= child_event
->parent
;
10513 * Do not destroy the 'original' grouping; because of the context
10514 * switch optimization the original events could've ended up in a
10515 * random child task.
10517 * If we were to destroy the original group, all group related
10518 * operations would cease to function properly after this random
10521 * Do destroy all inherited groups, we don't care about those
10522 * and being thorough is better.
10524 raw_spin_lock_irq(&child_ctx
->lock
);
10525 WARN_ON_ONCE(child_ctx
->is_active
);
10528 perf_group_detach(child_event
);
10529 list_del_event(child_event
, child_ctx
);
10530 child_event
->state
= PERF_EVENT_STATE_EXIT
; /* is_event_hup() */
10531 raw_spin_unlock_irq(&child_ctx
->lock
);
10534 * Parent events are governed by their filedesc, retain them.
10536 if (!parent_event
) {
10537 perf_event_wakeup(child_event
);
10541 * Child events can be cleaned up.
10544 sync_child_event(child_event
, child
);
10547 * Remove this event from the parent's list
10549 WARN_ON_ONCE(parent_event
->ctx
->parent_ctx
);
10550 mutex_lock(&parent_event
->child_mutex
);
10551 list_del_init(&child_event
->child_list
);
10552 mutex_unlock(&parent_event
->child_mutex
);
10555 * Kick perf_poll() for is_event_hup().
10557 perf_event_wakeup(parent_event
);
10558 free_event(child_event
);
10559 put_event(parent_event
);
10562 static void perf_event_exit_task_context(struct task_struct
*child
, int ctxn
)
10564 struct perf_event_context
*child_ctx
, *clone_ctx
= NULL
;
10565 struct perf_event
*child_event
, *next
;
10567 WARN_ON_ONCE(child
!= current
);
10569 child_ctx
= perf_pin_task_context(child
, ctxn
);
10574 * In order to reduce the amount of tricky in ctx tear-down, we hold
10575 * ctx::mutex over the entire thing. This serializes against almost
10576 * everything that wants to access the ctx.
10578 * The exception is sys_perf_event_open() /
10579 * perf_event_create_kernel_count() which does find_get_context()
10580 * without ctx::mutex (it cannot because of the move_group double mutex
10581 * lock thing). See the comments in perf_install_in_context().
10583 mutex_lock(&child_ctx
->mutex
);
10586 * In a single ctx::lock section, de-schedule the events and detach the
10587 * context from the task such that we cannot ever get it scheduled back
10590 raw_spin_lock_irq(&child_ctx
->lock
);
10591 task_ctx_sched_out(__get_cpu_context(child_ctx
), child_ctx
, EVENT_ALL
);
10594 * Now that the context is inactive, destroy the task <-> ctx relation
10595 * and mark the context dead.
10597 RCU_INIT_POINTER(child
->perf_event_ctxp
[ctxn
], NULL
);
10598 put_ctx(child_ctx
); /* cannot be last */
10599 WRITE_ONCE(child_ctx
->task
, TASK_TOMBSTONE
);
10600 put_task_struct(current
); /* cannot be last */
10602 clone_ctx
= unclone_ctx(child_ctx
);
10603 raw_spin_unlock_irq(&child_ctx
->lock
);
10606 put_ctx(clone_ctx
);
10609 * Report the task dead after unscheduling the events so that we
10610 * won't get any samples after PERF_RECORD_EXIT. We can however still
10611 * get a few PERF_RECORD_READ events.
10613 perf_event_task(child
, child_ctx
, 0);
10615 list_for_each_entry_safe(child_event
, next
, &child_ctx
->event_list
, event_entry
)
10616 perf_event_exit_event(child_event
, child_ctx
, child
);
10618 mutex_unlock(&child_ctx
->mutex
);
10620 put_ctx(child_ctx
);
10624 * When a child task exits, feed back event values to parent events.
10626 * Can be called with cred_guard_mutex held when called from
10627 * install_exec_creds().
10629 void perf_event_exit_task(struct task_struct
*child
)
10631 struct perf_event
*event
, *tmp
;
10634 mutex_lock(&child
->perf_event_mutex
);
10635 list_for_each_entry_safe(event
, tmp
, &child
->perf_event_list
,
10637 list_del_init(&event
->owner_entry
);
10640 * Ensure the list deletion is visible before we clear
10641 * the owner, closes a race against perf_release() where
10642 * we need to serialize on the owner->perf_event_mutex.
10644 smp_store_release(&event
->owner
, NULL
);
10646 mutex_unlock(&child
->perf_event_mutex
);
10648 for_each_task_context_nr(ctxn
)
10649 perf_event_exit_task_context(child
, ctxn
);
10652 * The perf_event_exit_task_context calls perf_event_task
10653 * with child's task_ctx, which generates EXIT events for
10654 * child contexts and sets child->perf_event_ctxp[] to NULL.
10655 * At this point we need to send EXIT events to cpu contexts.
10657 perf_event_task(child
, NULL
, 0);
10660 static void perf_free_event(struct perf_event
*event
,
10661 struct perf_event_context
*ctx
)
10663 struct perf_event
*parent
= event
->parent
;
10665 if (WARN_ON_ONCE(!parent
))
10668 mutex_lock(&parent
->child_mutex
);
10669 list_del_init(&event
->child_list
);
10670 mutex_unlock(&parent
->child_mutex
);
10674 raw_spin_lock_irq(&ctx
->lock
);
10675 perf_group_detach(event
);
10676 list_del_event(event
, ctx
);
10677 raw_spin_unlock_irq(&ctx
->lock
);
10682 * Free an unexposed, unused context as created by inheritance by
10683 * perf_event_init_task below, used by fork() in case of fail.
10685 * Not all locks are strictly required, but take them anyway to be nice and
10686 * help out with the lockdep assertions.
10688 void perf_event_free_task(struct task_struct
*task
)
10690 struct perf_event_context
*ctx
;
10691 struct perf_event
*event
, *tmp
;
10694 for_each_task_context_nr(ctxn
) {
10695 ctx
= task
->perf_event_ctxp
[ctxn
];
10699 mutex_lock(&ctx
->mutex
);
10700 raw_spin_lock_irq(&ctx
->lock
);
10702 * Destroy the task <-> ctx relation and mark the context dead.
10704 * This is important because even though the task hasn't been
10705 * exposed yet the context has been (through child_list).
10707 RCU_INIT_POINTER(task
->perf_event_ctxp
[ctxn
], NULL
);
10708 WRITE_ONCE(ctx
->task
, TASK_TOMBSTONE
);
10709 put_task_struct(task
); /* cannot be last */
10710 raw_spin_unlock_irq(&ctx
->lock
);
10712 list_for_each_entry_safe(event
, tmp
, &ctx
->event_list
, event_entry
)
10713 perf_free_event(event
, ctx
);
10715 mutex_unlock(&ctx
->mutex
);
10720 void perf_event_delayed_put(struct task_struct
*task
)
10724 for_each_task_context_nr(ctxn
)
10725 WARN_ON_ONCE(task
->perf_event_ctxp
[ctxn
]);
10728 struct file
*perf_event_get(unsigned int fd
)
10732 file
= fget_raw(fd
);
10734 return ERR_PTR(-EBADF
);
10736 if (file
->f_op
!= &perf_fops
) {
10738 return ERR_PTR(-EBADF
);
10744 const struct perf_event_attr
*perf_event_attrs(struct perf_event
*event
)
10747 return ERR_PTR(-EINVAL
);
10749 return &event
->attr
;
10753 * Inherit a event from parent task to child task.
10756 * - valid pointer on success
10757 * - NULL for orphaned events
10758 * - IS_ERR() on error
10760 static struct perf_event
*
10761 inherit_event(struct perf_event
*parent_event
,
10762 struct task_struct
*parent
,
10763 struct perf_event_context
*parent_ctx
,
10764 struct task_struct
*child
,
10765 struct perf_event
*group_leader
,
10766 struct perf_event_context
*child_ctx
)
10768 enum perf_event_active_state parent_state
= parent_event
->state
;
10769 struct perf_event
*child_event
;
10770 unsigned long flags
;
10773 * Instead of creating recursive hierarchies of events,
10774 * we link inherited events back to the original parent,
10775 * which has a filp for sure, which we use as the reference
10778 if (parent_event
->parent
)
10779 parent_event
= parent_event
->parent
;
10781 child_event
= perf_event_alloc(&parent_event
->attr
,
10784 group_leader
, parent_event
,
10786 if (IS_ERR(child_event
))
10787 return child_event
;
10790 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10791 * must be under the same lock in order to serialize against
10792 * perf_event_release_kernel(), such that either we must observe
10793 * is_orphaned_event() or they will observe us on the child_list.
10795 mutex_lock(&parent_event
->child_mutex
);
10796 if (is_orphaned_event(parent_event
) ||
10797 !atomic_long_inc_not_zero(&parent_event
->refcount
)) {
10798 mutex_unlock(&parent_event
->child_mutex
);
10799 free_event(child_event
);
10803 get_ctx(child_ctx
);
10806 * Make the child state follow the state of the parent event,
10807 * not its attr.disabled bit. We hold the parent's mutex,
10808 * so we won't race with perf_event_{en, dis}able_family.
10810 if (parent_state
>= PERF_EVENT_STATE_INACTIVE
)
10811 child_event
->state
= PERF_EVENT_STATE_INACTIVE
;
10813 child_event
->state
= PERF_EVENT_STATE_OFF
;
10815 if (parent_event
->attr
.freq
) {
10816 u64 sample_period
= parent_event
->hw
.sample_period
;
10817 struct hw_perf_event
*hwc
= &child_event
->hw
;
10819 hwc
->sample_period
= sample_period
;
10820 hwc
->last_period
= sample_period
;
10822 local64_set(&hwc
->period_left
, sample_period
);
10825 child_event
->ctx
= child_ctx
;
10826 child_event
->overflow_handler
= parent_event
->overflow_handler
;
10827 child_event
->overflow_handler_context
10828 = parent_event
->overflow_handler_context
;
10831 * Precalculate sample_data sizes
10833 perf_event__header_size(child_event
);
10834 perf_event__id_header_size(child_event
);
10837 * Link it up in the child's context:
10839 raw_spin_lock_irqsave(&child_ctx
->lock
, flags
);
10840 add_event_to_ctx(child_event
, child_ctx
);
10841 raw_spin_unlock_irqrestore(&child_ctx
->lock
, flags
);
10844 * Link this into the parent event's child list
10846 list_add_tail(&child_event
->child_list
, &parent_event
->child_list
);
10847 mutex_unlock(&parent_event
->child_mutex
);
10849 return child_event
;
10853 * Inherits an event group.
10855 * This will quietly suppress orphaned events; !inherit_event() is not an error.
10856 * This matches with perf_event_release_kernel() removing all child events.
10862 static int inherit_group(struct perf_event
*parent_event
,
10863 struct task_struct
*parent
,
10864 struct perf_event_context
*parent_ctx
,
10865 struct task_struct
*child
,
10866 struct perf_event_context
*child_ctx
)
10868 struct perf_event
*leader
;
10869 struct perf_event
*sub
;
10870 struct perf_event
*child_ctr
;
10872 leader
= inherit_event(parent_event
, parent
, parent_ctx
,
10873 child
, NULL
, child_ctx
);
10874 if (IS_ERR(leader
))
10875 return PTR_ERR(leader
);
10877 * @leader can be NULL here because of is_orphaned_event(). In this
10878 * case inherit_event() will create individual events, similar to what
10879 * perf_group_detach() would do anyway.
10881 list_for_each_entry(sub
, &parent_event
->sibling_list
, group_entry
) {
10882 child_ctr
= inherit_event(sub
, parent
, parent_ctx
,
10883 child
, leader
, child_ctx
);
10884 if (IS_ERR(child_ctr
))
10885 return PTR_ERR(child_ctr
);
10891 * Creates the child task context and tries to inherit the event-group.
10893 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
10894 * inherited_all set when we 'fail' to inherit an orphaned event; this is
10895 * consistent with perf_event_release_kernel() removing all child events.
10902 inherit_task_group(struct perf_event
*event
, struct task_struct
*parent
,
10903 struct perf_event_context
*parent_ctx
,
10904 struct task_struct
*child
, int ctxn
,
10905 int *inherited_all
)
10908 struct perf_event_context
*child_ctx
;
10910 if (!event
->attr
.inherit
) {
10911 *inherited_all
= 0;
10915 child_ctx
= child
->perf_event_ctxp
[ctxn
];
10918 * This is executed from the parent task context, so
10919 * inherit events that have been marked for cloning.
10920 * First allocate and initialize a context for the
10923 child_ctx
= alloc_perf_context(parent_ctx
->pmu
, child
);
10927 child
->perf_event_ctxp
[ctxn
] = child_ctx
;
10930 ret
= inherit_group(event
, parent
, parent_ctx
,
10934 *inherited_all
= 0;
10940 * Initialize the perf_event context in task_struct
10942 static int perf_event_init_context(struct task_struct
*child
, int ctxn
)
10944 struct perf_event_context
*child_ctx
, *parent_ctx
;
10945 struct perf_event_context
*cloned_ctx
;
10946 struct perf_event
*event
;
10947 struct task_struct
*parent
= current
;
10948 int inherited_all
= 1;
10949 unsigned long flags
;
10952 if (likely(!parent
->perf_event_ctxp
[ctxn
]))
10956 * If the parent's context is a clone, pin it so it won't get
10957 * swapped under us.
10959 parent_ctx
= perf_pin_task_context(parent
, ctxn
);
10964 * No need to check if parent_ctx != NULL here; since we saw
10965 * it non-NULL earlier, the only reason for it to become NULL
10966 * is if we exit, and since we're currently in the middle of
10967 * a fork we can't be exiting at the same time.
10971 * Lock the parent list. No need to lock the child - not PID
10972 * hashed yet and not running, so nobody can access it.
10974 mutex_lock(&parent_ctx
->mutex
);
10977 * We dont have to disable NMIs - we are only looking at
10978 * the list, not manipulating it:
10980 list_for_each_entry(event
, &parent_ctx
->pinned_groups
, group_entry
) {
10981 ret
= inherit_task_group(event
, parent
, parent_ctx
,
10982 child
, ctxn
, &inherited_all
);
10988 * We can't hold ctx->lock when iterating the ->flexible_group list due
10989 * to allocations, but we need to prevent rotation because
10990 * rotate_ctx() will change the list from interrupt context.
10992 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
10993 parent_ctx
->rotate_disable
= 1;
10994 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
10996 list_for_each_entry(event
, &parent_ctx
->flexible_groups
, group_entry
) {
10997 ret
= inherit_task_group(event
, parent
, parent_ctx
,
10998 child
, ctxn
, &inherited_all
);
11003 raw_spin_lock_irqsave(&parent_ctx
->lock
, flags
);
11004 parent_ctx
->rotate_disable
= 0;
11006 child_ctx
= child
->perf_event_ctxp
[ctxn
];
11008 if (child_ctx
&& inherited_all
) {
11010 * Mark the child context as a clone of the parent
11011 * context, or of whatever the parent is a clone of.
11013 * Note that if the parent is a clone, the holding of
11014 * parent_ctx->lock avoids it from being uncloned.
11016 cloned_ctx
= parent_ctx
->parent_ctx
;
11018 child_ctx
->parent_ctx
= cloned_ctx
;
11019 child_ctx
->parent_gen
= parent_ctx
->parent_gen
;
11021 child_ctx
->parent_ctx
= parent_ctx
;
11022 child_ctx
->parent_gen
= parent_ctx
->generation
;
11024 get_ctx(child_ctx
->parent_ctx
);
11027 raw_spin_unlock_irqrestore(&parent_ctx
->lock
, flags
);
11029 mutex_unlock(&parent_ctx
->mutex
);
11031 perf_unpin_context(parent_ctx
);
11032 put_ctx(parent_ctx
);
11038 * Initialize the perf_event context in task_struct
11040 int perf_event_init_task(struct task_struct
*child
)
11044 memset(child
->perf_event_ctxp
, 0, sizeof(child
->perf_event_ctxp
));
11045 mutex_init(&child
->perf_event_mutex
);
11046 INIT_LIST_HEAD(&child
->perf_event_list
);
11048 for_each_task_context_nr(ctxn
) {
11049 ret
= perf_event_init_context(child
, ctxn
);
11051 perf_event_free_task(child
);
11059 static void __init
perf_event_init_all_cpus(void)
11061 struct swevent_htable
*swhash
;
11064 zalloc_cpumask_var(&perf_online_mask
, GFP_KERNEL
);
11066 for_each_possible_cpu(cpu
) {
11067 swhash
= &per_cpu(swevent_htable
, cpu
);
11068 mutex_init(&swhash
->hlist_mutex
);
11069 INIT_LIST_HEAD(&per_cpu(active_ctx_list
, cpu
));
11071 INIT_LIST_HEAD(&per_cpu(pmu_sb_events
.list
, cpu
));
11072 raw_spin_lock_init(&per_cpu(pmu_sb_events
.lock
, cpu
));
11074 #ifdef CONFIG_CGROUP_PERF
11075 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list
, cpu
));
11077 INIT_LIST_HEAD(&per_cpu(sched_cb_list
, cpu
));
11081 void perf_swevent_init_cpu(unsigned int cpu
)
11083 struct swevent_htable
*swhash
= &per_cpu(swevent_htable
, cpu
);
11085 mutex_lock(&swhash
->hlist_mutex
);
11086 if (swhash
->hlist_refcount
> 0 && !swevent_hlist_deref(swhash
)) {
11087 struct swevent_hlist
*hlist
;
11089 hlist
= kzalloc_node(sizeof(*hlist
), GFP_KERNEL
, cpu_to_node(cpu
));
11091 rcu_assign_pointer(swhash
->swevent_hlist
, hlist
);
11093 mutex_unlock(&swhash
->hlist_mutex
);
11096 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11097 static void __perf_event_exit_context(void *__info
)
11099 struct perf_event_context
*ctx
= __info
;
11100 struct perf_cpu_context
*cpuctx
= __get_cpu_context(ctx
);
11101 struct perf_event
*event
;
11103 raw_spin_lock(&ctx
->lock
);
11104 list_for_each_entry(event
, &ctx
->event_list
, event_entry
)
11105 __perf_remove_from_context(event
, cpuctx
, ctx
, (void *)DETACH_GROUP
);
11106 raw_spin_unlock(&ctx
->lock
);
11109 static void perf_event_exit_cpu_context(int cpu
)
11111 struct perf_cpu_context
*cpuctx
;
11112 struct perf_event_context
*ctx
;
11115 mutex_lock(&pmus_lock
);
11116 list_for_each_entry(pmu
, &pmus
, entry
) {
11117 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
11118 ctx
= &cpuctx
->ctx
;
11120 mutex_lock(&ctx
->mutex
);
11121 smp_call_function_single(cpu
, __perf_event_exit_context
, ctx
, 1);
11122 cpuctx
->online
= 0;
11123 mutex_unlock(&ctx
->mutex
);
11125 cpumask_clear_cpu(cpu
, perf_online_mask
);
11126 mutex_unlock(&pmus_lock
);
11130 static void perf_event_exit_cpu_context(int cpu
) { }
11134 int perf_event_init_cpu(unsigned int cpu
)
11136 struct perf_cpu_context
*cpuctx
;
11137 struct perf_event_context
*ctx
;
11140 perf_swevent_init_cpu(cpu
);
11142 mutex_lock(&pmus_lock
);
11143 cpumask_set_cpu(cpu
, perf_online_mask
);
11144 list_for_each_entry(pmu
, &pmus
, entry
) {
11145 cpuctx
= per_cpu_ptr(pmu
->pmu_cpu_context
, cpu
);
11146 ctx
= &cpuctx
->ctx
;
11148 mutex_lock(&ctx
->mutex
);
11149 cpuctx
->online
= 1;
11150 mutex_unlock(&ctx
->mutex
);
11152 mutex_unlock(&pmus_lock
);
11157 int perf_event_exit_cpu(unsigned int cpu
)
11159 perf_event_exit_cpu_context(cpu
);
11164 perf_reboot(struct notifier_block
*notifier
, unsigned long val
, void *v
)
11168 for_each_online_cpu(cpu
)
11169 perf_event_exit_cpu(cpu
);
11175 * Run the perf reboot notifier at the very last possible moment so that
11176 * the generic watchdog code runs as long as possible.
11178 static struct notifier_block perf_reboot_notifier
= {
11179 .notifier_call
= perf_reboot
,
11180 .priority
= INT_MIN
,
11183 void __init
perf_event_init(void)
11187 idr_init(&pmu_idr
);
11189 perf_event_init_all_cpus();
11190 init_srcu_struct(&pmus_srcu
);
11191 perf_pmu_register(&perf_swevent
, "software", PERF_TYPE_SOFTWARE
);
11192 perf_pmu_register(&perf_cpu_clock
, NULL
, -1);
11193 perf_pmu_register(&perf_task_clock
, NULL
, -1);
11194 perf_tp_register();
11195 perf_event_init_cpu(smp_processor_id());
11196 register_reboot_notifier(&perf_reboot_notifier
);
11198 ret
= init_hw_breakpoint();
11199 WARN(ret
, "hw_breakpoint initialization failed with: %d", ret
);
11202 * Build time assertion that we keep the data_head at the intended
11203 * location. IOW, validation we got the __reserved[] size right.
11205 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page
, data_head
))
11209 ssize_t
perf_event_sysfs_show(struct device
*dev
, struct device_attribute
*attr
,
11212 struct perf_pmu_events_attr
*pmu_attr
=
11213 container_of(attr
, struct perf_pmu_events_attr
, attr
);
11215 if (pmu_attr
->event_str
)
11216 return sprintf(page
, "%s\n", pmu_attr
->event_str
);
11220 EXPORT_SYMBOL_GPL(perf_event_sysfs_show
);
11222 static int __init
perf_event_sysfs_init(void)
11227 mutex_lock(&pmus_lock
);
11229 ret
= bus_register(&pmu_bus
);
11233 list_for_each_entry(pmu
, &pmus
, entry
) {
11234 if (!pmu
->name
|| pmu
->type
< 0)
11237 ret
= pmu_dev_alloc(pmu
);
11238 WARN(ret
, "Failed to register pmu: %s, reason %d\n", pmu
->name
, ret
);
11240 pmu_bus_running
= 1;
11244 mutex_unlock(&pmus_lock
);
11248 device_initcall(perf_event_sysfs_init
);
11250 #ifdef CONFIG_CGROUP_PERF
11251 static struct cgroup_subsys_state
*
11252 perf_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
11254 struct perf_cgroup
*jc
;
11256 jc
= kzalloc(sizeof(*jc
), GFP_KERNEL
);
11258 return ERR_PTR(-ENOMEM
);
11260 jc
->info
= alloc_percpu(struct perf_cgroup_info
);
11263 return ERR_PTR(-ENOMEM
);
11269 static void perf_cgroup_css_free(struct cgroup_subsys_state
*css
)
11271 struct perf_cgroup
*jc
= container_of(css
, struct perf_cgroup
, css
);
11273 free_percpu(jc
->info
);
11277 static int __perf_cgroup_move(void *info
)
11279 struct task_struct
*task
= info
;
11281 perf_cgroup_switch(task
, PERF_CGROUP_SWOUT
| PERF_CGROUP_SWIN
);
11286 static void perf_cgroup_attach(struct cgroup_taskset
*tset
)
11288 struct task_struct
*task
;
11289 struct cgroup_subsys_state
*css
;
11291 cgroup_taskset_for_each(task
, css
, tset
)
11292 task_function_call(task
, __perf_cgroup_move
, task
);
11295 struct cgroup_subsys perf_event_cgrp_subsys
= {
11296 .css_alloc
= perf_cgroup_css_alloc
,
11297 .css_free
= perf_cgroup_css_free
,
11298 .attach
= perf_cgroup_attach
,
11300 * Implicitly enable on dfl hierarchy so that perf events can
11301 * always be filtered by cgroup2 path as long as perf_event
11302 * controller is not mounted on a legacy hierarchy.
11304 .implicit_on_dfl
= true,
11307 #endif /* CONFIG_CGROUP_PERF */