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>
50 #include <asm/irq_regs.h>
52 static struct workqueue_struct *perf_wq;
54 typedef int (*remote_function_f)(void *);
56 struct remote_function_call {
57 struct task_struct *p;
58 remote_function_f func;
63 static void remote_function(void *data)
65 struct remote_function_call *tfc = data;
66 struct task_struct *p = tfc->p;
70 if (task_cpu(p) != smp_processor_id() || !task_curr(p))
74 tfc->ret = tfc->func(tfc->info);
78 * task_function_call - call a function on the cpu on which a task runs
79 * @p: the task to evaluate
80 * @func: the function to be called
81 * @info: the function call argument
83 * Calls the function @func when the task is currently running. This might
84 * be on the current CPU, which just calls the function directly
86 * returns: @func return value, or
87 * -ESRCH - when the process isn't running
88 * -EAGAIN - when the process moved away
91 task_function_call(struct task_struct *p, remote_function_f func, void *info)
93 struct remote_function_call data = {
97 .ret = -ESRCH, /* No such (running) process */
101 smp_call_function_single(task_cpu(p), remote_function, &data, 1);
107 * cpu_function_call - call a function on the cpu
108 * @func: the function to be called
109 * @info: the function call argument
111 * Calls the function @func on the remote cpu.
113 * returns: @func return value or -ENXIO when the cpu is offline
115 static int cpu_function_call(int cpu, remote_function_f func, void *info)
117 struct remote_function_call data = {
121 .ret = -ENXIO, /* No such CPU */
124 smp_call_function_single(cpu, remote_function, &data, 1);
129 #define EVENT_OWNER_KERNEL ((void *) -1)
131 static bool is_kernel_event(struct perf_event *event)
133 return event->owner == EVENT_OWNER_KERNEL;
136 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
137 PERF_FLAG_FD_OUTPUT |\
138 PERF_FLAG_PID_CGROUP |\
139 PERF_FLAG_FD_CLOEXEC)
142 * branch priv levels that need permission checks
144 #define PERF_SAMPLE_BRANCH_PERM_PLM \
145 (PERF_SAMPLE_BRANCH_KERNEL |\
146 PERF_SAMPLE_BRANCH_HV)
149 EVENT_FLEXIBLE = 0x1,
151 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
155 * perf_sched_events : >0 events exist
156 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
158 struct static_key_deferred perf_sched_events __read_mostly;
159 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
160 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
162 static atomic_t nr_mmap_events __read_mostly;
163 static atomic_t nr_comm_events __read_mostly;
164 static atomic_t nr_task_events __read_mostly;
165 static atomic_t nr_freq_events __read_mostly;
166 static atomic_t nr_switch_events __read_mostly;
168 static LIST_HEAD(pmus);
169 static DEFINE_MUTEX(pmus_lock);
170 static struct srcu_struct pmus_srcu;
173 * perf event paranoia level:
174 * -1 - not paranoid at all
175 * 0 - disallow raw tracepoint access for unpriv
176 * 1 - disallow cpu events for unpriv
177 * 2 - disallow kernel profiling for unpriv
179 int sysctl_perf_event_paranoid __read_mostly = 1;
181 /* Minimum for 512 kiB + 1 user control page */
182 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
185 * max perf event sample rate
187 #define DEFAULT_MAX_SAMPLE_RATE 100000
188 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
189 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
191 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
193 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
194 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
196 static int perf_sample_allowed_ns __read_mostly =
197 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
199 static void update_perf_cpu_limits(void)
201 u64 tmp = perf_sample_period_ns;
203 tmp *= sysctl_perf_cpu_time_max_percent;
205 ACCESS_ONCE(perf_sample_allowed_ns) = tmp;
208 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
210 int perf_proc_update_handler(struct ctl_table *table, int write,
211 void __user *buffer, size_t *lenp,
214 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
219 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
220 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
221 update_perf_cpu_limits();
226 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
228 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
229 void __user *buffer, size_t *lenp,
232 int ret = proc_dointvec(table, write, buffer, lenp, ppos);
237 update_perf_cpu_limits();
243 * perf samples are done in some very critical code paths (NMIs).
244 * If they take too much CPU time, the system can lock up and not
245 * get any real work done. This will drop the sample rate when
246 * we detect that events are taking too long.
248 #define NR_ACCUMULATED_SAMPLES 128
249 static DEFINE_PER_CPU(u64, running_sample_length);
251 static void perf_duration_warn(struct irq_work *w)
253 u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
254 u64 avg_local_sample_len;
255 u64 local_samples_len;
257 local_samples_len = __this_cpu_read(running_sample_length);
258 avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
260 printk_ratelimited(KERN_WARNING
261 "perf interrupt took too long (%lld > %lld), lowering "
262 "kernel.perf_event_max_sample_rate to %d\n",
263 avg_local_sample_len, allowed_ns >> 1,
264 sysctl_perf_event_sample_rate);
267 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
269 void perf_sample_event_took(u64 sample_len_ns)
271 u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
272 u64 avg_local_sample_len;
273 u64 local_samples_len;
278 /* decay the counter by 1 average sample */
279 local_samples_len = __this_cpu_read(running_sample_length);
280 local_samples_len -= local_samples_len/NR_ACCUMULATED_SAMPLES;
281 local_samples_len += sample_len_ns;
282 __this_cpu_write(running_sample_length, local_samples_len);
285 * note: this will be biased artifically low until we have
286 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
287 * from having to maintain a count.
289 avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
291 if (avg_local_sample_len <= allowed_ns)
294 if (max_samples_per_tick <= 1)
297 max_samples_per_tick = DIV_ROUND_UP(max_samples_per_tick, 2);
298 sysctl_perf_event_sample_rate = max_samples_per_tick * HZ;
299 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
301 update_perf_cpu_limits();
303 if (!irq_work_queue(&perf_duration_work)) {
304 early_printk("perf interrupt took too long (%lld > %lld), lowering "
305 "kernel.perf_event_max_sample_rate to %d\n",
306 avg_local_sample_len, allowed_ns >> 1,
307 sysctl_perf_event_sample_rate);
311 static atomic64_t perf_event_id;
313 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
314 enum event_type_t event_type);
316 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
317 enum event_type_t event_type,
318 struct task_struct *task);
320 static void update_context_time(struct perf_event_context *ctx);
321 static u64 perf_event_time(struct perf_event *event);
323 void __weak perf_event_print_debug(void) { }
325 extern __weak const char *perf_pmu_name(void)
330 static inline u64 perf_clock(void)
332 return local_clock();
335 static inline u64 perf_event_clock(struct perf_event *event)
337 return event->clock();
340 static inline struct perf_cpu_context *
341 __get_cpu_context(struct perf_event_context *ctx)
343 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
346 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
347 struct perf_event_context *ctx)
349 raw_spin_lock(&cpuctx->ctx.lock);
351 raw_spin_lock(&ctx->lock);
354 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
355 struct perf_event_context *ctx)
358 raw_spin_unlock(&ctx->lock);
359 raw_spin_unlock(&cpuctx->ctx.lock);
362 #ifdef CONFIG_CGROUP_PERF
365 perf_cgroup_match(struct perf_event *event)
367 struct perf_event_context *ctx = event->ctx;
368 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
370 /* @event doesn't care about cgroup */
374 /* wants specific cgroup scope but @cpuctx isn't associated with any */
379 * Cgroup scoping is recursive. An event enabled for a cgroup is
380 * also enabled for all its descendant cgroups. If @cpuctx's
381 * cgroup is a descendant of @event's (the test covers identity
382 * case), it's a match.
384 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
385 event->cgrp->css.cgroup);
388 static inline void perf_detach_cgroup(struct perf_event *event)
390 css_put(&event->cgrp->css);
394 static inline int is_cgroup_event(struct perf_event *event)
396 return event->cgrp != NULL;
399 static inline u64 perf_cgroup_event_time(struct perf_event *event)
401 struct perf_cgroup_info *t;
403 t = per_cpu_ptr(event->cgrp->info, event->cpu);
407 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
409 struct perf_cgroup_info *info;
414 info = this_cpu_ptr(cgrp->info);
416 info->time += now - info->timestamp;
417 info->timestamp = now;
420 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
422 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
424 __update_cgrp_time(cgrp_out);
427 static inline void update_cgrp_time_from_event(struct perf_event *event)
429 struct perf_cgroup *cgrp;
432 * ensure we access cgroup data only when needed and
433 * when we know the cgroup is pinned (css_get)
435 if (!is_cgroup_event(event))
438 cgrp = perf_cgroup_from_task(current, event->ctx);
440 * Do not update time when cgroup is not active
442 if (cgrp == event->cgrp)
443 __update_cgrp_time(event->cgrp);
447 perf_cgroup_set_timestamp(struct task_struct *task,
448 struct perf_event_context *ctx)
450 struct perf_cgroup *cgrp;
451 struct perf_cgroup_info *info;
454 * ctx->lock held by caller
455 * ensure we do not access cgroup data
456 * unless we have the cgroup pinned (css_get)
458 if (!task || !ctx->nr_cgroups)
461 cgrp = perf_cgroup_from_task(task, ctx);
462 info = this_cpu_ptr(cgrp->info);
463 info->timestamp = ctx->timestamp;
466 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
467 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
470 * reschedule events based on the cgroup constraint of task.
472 * mode SWOUT : schedule out everything
473 * mode SWIN : schedule in based on cgroup for next
475 static void perf_cgroup_switch(struct task_struct *task, int mode)
477 struct perf_cpu_context *cpuctx;
482 * disable interrupts to avoid geting nr_cgroup
483 * changes via __perf_event_disable(). Also
486 local_irq_save(flags);
489 * we reschedule only in the presence of cgroup
490 * constrained events.
493 list_for_each_entry_rcu(pmu, &pmus, entry) {
494 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
495 if (cpuctx->unique_pmu != pmu)
496 continue; /* ensure we process each cpuctx once */
499 * perf_cgroup_events says at least one
500 * context on this CPU has cgroup events.
502 * ctx->nr_cgroups reports the number of cgroup
503 * events for a context.
505 if (cpuctx->ctx.nr_cgroups > 0) {
506 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
507 perf_pmu_disable(cpuctx->ctx.pmu);
509 if (mode & PERF_CGROUP_SWOUT) {
510 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
512 * must not be done before ctxswout due
513 * to event_filter_match() in event_sched_out()
518 if (mode & PERF_CGROUP_SWIN) {
519 WARN_ON_ONCE(cpuctx->cgrp);
521 * set cgrp before ctxsw in to allow
522 * event_filter_match() to not have to pass
524 * we pass the cpuctx->ctx to perf_cgroup_from_task()
525 * because cgorup events are only per-cpu
527 cpuctx->cgrp = perf_cgroup_from_task(task, &cpuctx->ctx);
528 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
530 perf_pmu_enable(cpuctx->ctx.pmu);
531 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
535 local_irq_restore(flags);
538 static inline void perf_cgroup_sched_out(struct task_struct *task,
539 struct task_struct *next)
541 struct perf_cgroup *cgrp1;
542 struct perf_cgroup *cgrp2 = NULL;
546 * we come here when we know perf_cgroup_events > 0
547 * we do not need to pass the ctx here because we know
548 * we are holding the rcu lock
550 cgrp1 = perf_cgroup_from_task(task, NULL);
553 * next is NULL when called from perf_event_enable_on_exec()
554 * that will systematically cause a cgroup_switch()
557 cgrp2 = perf_cgroup_from_task(next, NULL);
560 * only schedule out current cgroup events if we know
561 * that we are switching to a different cgroup. Otherwise,
562 * do no touch the cgroup events.
565 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
570 static inline void perf_cgroup_sched_in(struct task_struct *prev,
571 struct task_struct *task)
573 struct perf_cgroup *cgrp1;
574 struct perf_cgroup *cgrp2 = NULL;
578 * we come here when we know perf_cgroup_events > 0
579 * we do not need to pass the ctx here because we know
580 * we are holding the rcu lock
582 cgrp1 = perf_cgroup_from_task(task, NULL);
584 /* prev can never be NULL */
585 cgrp2 = perf_cgroup_from_task(prev, NULL);
588 * only need to schedule in cgroup events if we are changing
589 * cgroup during ctxsw. Cgroup events were not scheduled
590 * out of ctxsw out if that was not the case.
593 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
598 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
599 struct perf_event_attr *attr,
600 struct perf_event *group_leader)
602 struct perf_cgroup *cgrp;
603 struct cgroup_subsys_state *css;
604 struct fd f = fdget(fd);
610 css = css_tryget_online_from_dir(f.file->f_path.dentry,
611 &perf_event_cgrp_subsys);
617 cgrp = container_of(css, struct perf_cgroup, css);
621 * all events in a group must monitor
622 * the same cgroup because a task belongs
623 * to only one perf cgroup at a time
625 if (group_leader && group_leader->cgrp != cgrp) {
626 perf_detach_cgroup(event);
635 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
637 struct perf_cgroup_info *t;
638 t = per_cpu_ptr(event->cgrp->info, event->cpu);
639 event->shadow_ctx_time = now - t->timestamp;
643 perf_cgroup_defer_enabled(struct perf_event *event)
646 * when the current task's perf cgroup does not match
647 * the event's, we need to remember to call the
648 * perf_mark_enable() function the first time a task with
649 * a matching perf cgroup is scheduled in.
651 if (is_cgroup_event(event) && !perf_cgroup_match(event))
652 event->cgrp_defer_enabled = 1;
656 perf_cgroup_mark_enabled(struct perf_event *event,
657 struct perf_event_context *ctx)
659 struct perf_event *sub;
660 u64 tstamp = perf_event_time(event);
662 if (!event->cgrp_defer_enabled)
665 event->cgrp_defer_enabled = 0;
667 event->tstamp_enabled = tstamp - event->total_time_enabled;
668 list_for_each_entry(sub, &event->sibling_list, group_entry) {
669 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
670 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
671 sub->cgrp_defer_enabled = 0;
675 #else /* !CONFIG_CGROUP_PERF */
678 perf_cgroup_match(struct perf_event *event)
683 static inline void perf_detach_cgroup(struct perf_event *event)
686 static inline int is_cgroup_event(struct perf_event *event)
691 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
696 static inline void update_cgrp_time_from_event(struct perf_event *event)
700 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
704 static inline void perf_cgroup_sched_out(struct task_struct *task,
705 struct task_struct *next)
709 static inline void perf_cgroup_sched_in(struct task_struct *prev,
710 struct task_struct *task)
714 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
715 struct perf_event_attr *attr,
716 struct perf_event *group_leader)
722 perf_cgroup_set_timestamp(struct task_struct *task,
723 struct perf_event_context *ctx)
728 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
733 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
737 static inline u64 perf_cgroup_event_time(struct perf_event *event)
743 perf_cgroup_defer_enabled(struct perf_event *event)
748 perf_cgroup_mark_enabled(struct perf_event *event,
749 struct perf_event_context *ctx)
755 * set default to be dependent on timer tick just
758 #define PERF_CPU_HRTIMER (1000 / HZ)
760 * function must be called with interrupts disbled
762 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
764 struct perf_cpu_context *cpuctx;
767 WARN_ON(!irqs_disabled());
769 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
770 rotations = perf_rotate_context(cpuctx);
772 raw_spin_lock(&cpuctx->hrtimer_lock);
774 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
776 cpuctx->hrtimer_active = 0;
777 raw_spin_unlock(&cpuctx->hrtimer_lock);
779 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
782 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
784 struct hrtimer *timer = &cpuctx->hrtimer;
785 struct pmu *pmu = cpuctx->ctx.pmu;
788 /* no multiplexing needed for SW PMU */
789 if (pmu->task_ctx_nr == perf_sw_context)
793 * check default is sane, if not set then force to
794 * default interval (1/tick)
796 interval = pmu->hrtimer_interval_ms;
798 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
800 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
802 raw_spin_lock_init(&cpuctx->hrtimer_lock);
803 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
804 timer->function = perf_mux_hrtimer_handler;
807 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
809 struct hrtimer *timer = &cpuctx->hrtimer;
810 struct pmu *pmu = cpuctx->ctx.pmu;
814 if (pmu->task_ctx_nr == perf_sw_context)
817 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
818 if (!cpuctx->hrtimer_active) {
819 cpuctx->hrtimer_active = 1;
820 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
821 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
823 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
828 void perf_pmu_disable(struct pmu *pmu)
830 int *count = this_cpu_ptr(pmu->pmu_disable_count);
832 pmu->pmu_disable(pmu);
835 void perf_pmu_enable(struct pmu *pmu)
837 int *count = this_cpu_ptr(pmu->pmu_disable_count);
839 pmu->pmu_enable(pmu);
842 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
845 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
846 * perf_event_task_tick() are fully serialized because they're strictly cpu
847 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
848 * disabled, while perf_event_task_tick is called from IRQ context.
850 static void perf_event_ctx_activate(struct perf_event_context *ctx)
852 struct list_head *head = this_cpu_ptr(&active_ctx_list);
854 WARN_ON(!irqs_disabled());
856 WARN_ON(!list_empty(&ctx->active_ctx_list));
858 list_add(&ctx->active_ctx_list, head);
861 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
863 WARN_ON(!irqs_disabled());
865 WARN_ON(list_empty(&ctx->active_ctx_list));
867 list_del_init(&ctx->active_ctx_list);
870 static void get_ctx(struct perf_event_context *ctx)
872 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
875 static void free_ctx(struct rcu_head *head)
877 struct perf_event_context *ctx;
879 ctx = container_of(head, struct perf_event_context, rcu_head);
880 kfree(ctx->task_ctx_data);
884 static void put_ctx(struct perf_event_context *ctx)
886 if (atomic_dec_and_test(&ctx->refcount)) {
888 put_ctx(ctx->parent_ctx);
890 put_task_struct(ctx->task);
891 call_rcu(&ctx->rcu_head, free_ctx);
896 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
897 * perf_pmu_migrate_context() we need some magic.
899 * Those places that change perf_event::ctx will hold both
900 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
902 * Lock ordering is by mutex address. There are two other sites where
903 * perf_event_context::mutex nests and those are:
905 * - perf_event_exit_task_context() [ child , 0 ]
906 * __perf_event_exit_task()
908 * put_event() [ parent, 1 ]
910 * - perf_event_init_context() [ parent, 0 ]
911 * inherit_task_group()
916 * perf_try_init_event() [ child , 1 ]
918 * While it appears there is an obvious deadlock here -- the parent and child
919 * nesting levels are inverted between the two. This is in fact safe because
920 * life-time rules separate them. That is an exiting task cannot fork, and a
921 * spawning task cannot (yet) exit.
923 * But remember that that these are parent<->child context relations, and
924 * migration does not affect children, therefore these two orderings should not
927 * The change in perf_event::ctx does not affect children (as claimed above)
928 * because the sys_perf_event_open() case will install a new event and break
929 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
930 * concerned with cpuctx and that doesn't have children.
932 * The places that change perf_event::ctx will issue:
934 * perf_remove_from_context();
936 * perf_install_in_context();
938 * to affect the change. The remove_from_context() + synchronize_rcu() should
939 * quiesce the event, after which we can install it in the new location. This
940 * means that only external vectors (perf_fops, prctl) can perturb the event
941 * while in transit. Therefore all such accessors should also acquire
942 * perf_event_context::mutex to serialize against this.
944 * However; because event->ctx can change while we're waiting to acquire
945 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
949 * task_struct::perf_event_mutex
950 * perf_event_context::mutex
951 * perf_event_context::lock
952 * perf_event::child_mutex;
953 * perf_event::mmap_mutex
956 static struct perf_event_context *
957 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
959 struct perf_event_context *ctx;
963 ctx = ACCESS_ONCE(event->ctx);
964 if (!atomic_inc_not_zero(&ctx->refcount)) {
970 mutex_lock_nested(&ctx->mutex, nesting);
971 if (event->ctx != ctx) {
972 mutex_unlock(&ctx->mutex);
980 static inline struct perf_event_context *
981 perf_event_ctx_lock(struct perf_event *event)
983 return perf_event_ctx_lock_nested(event, 0);
986 static void perf_event_ctx_unlock(struct perf_event *event,
987 struct perf_event_context *ctx)
989 mutex_unlock(&ctx->mutex);
994 * This must be done under the ctx->lock, such as to serialize against
995 * context_equiv(), therefore we cannot call put_ctx() since that might end up
996 * calling scheduler related locks and ctx->lock nests inside those.
998 static __must_check struct perf_event_context *
999 unclone_ctx(struct perf_event_context *ctx)
1001 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1003 lockdep_assert_held(&ctx->lock);
1006 ctx->parent_ctx = NULL;
1012 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1015 * only top level events have the pid namespace they were created in
1018 event = event->parent;
1020 return task_tgid_nr_ns(p, event->ns);
1023 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1026 * only top level events have the pid namespace they were created in
1029 event = event->parent;
1031 return task_pid_nr_ns(p, event->ns);
1035 * If we inherit events we want to return the parent event id
1038 static u64 primary_event_id(struct perf_event *event)
1043 id = event->parent->id;
1049 * Get the perf_event_context for a task and lock it.
1050 * This has to cope with with the fact that until it is locked,
1051 * the context could get moved to another task.
1053 static struct perf_event_context *
1054 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1056 struct perf_event_context *ctx;
1060 * One of the few rules of preemptible RCU is that one cannot do
1061 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1062 * part of the read side critical section was irqs-enabled -- see
1063 * rcu_read_unlock_special().
1065 * Since ctx->lock nests under rq->lock we must ensure the entire read
1066 * side critical section has interrupts disabled.
1068 local_irq_save(*flags);
1070 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1073 * If this context is a clone of another, it might
1074 * get swapped for another underneath us by
1075 * perf_event_task_sched_out, though the
1076 * rcu_read_lock() protects us from any context
1077 * getting freed. Lock the context and check if it
1078 * got swapped before we could get the lock, and retry
1079 * if so. If we locked the right context, then it
1080 * can't get swapped on us any more.
1082 raw_spin_lock(&ctx->lock);
1083 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1084 raw_spin_unlock(&ctx->lock);
1086 local_irq_restore(*flags);
1090 if (!atomic_inc_not_zero(&ctx->refcount)) {
1091 raw_spin_unlock(&ctx->lock);
1097 local_irq_restore(*flags);
1102 * Get the context for a task and increment its pin_count so it
1103 * can't get swapped to another task. This also increments its
1104 * reference count so that the context can't get freed.
1106 static struct perf_event_context *
1107 perf_pin_task_context(struct task_struct *task, int ctxn)
1109 struct perf_event_context *ctx;
1110 unsigned long flags;
1112 ctx = perf_lock_task_context(task, ctxn, &flags);
1115 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1120 static void perf_unpin_context(struct perf_event_context *ctx)
1122 unsigned long flags;
1124 raw_spin_lock_irqsave(&ctx->lock, flags);
1126 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1130 * Update the record of the current time in a context.
1132 static void update_context_time(struct perf_event_context *ctx)
1134 u64 now = perf_clock();
1136 ctx->time += now - ctx->timestamp;
1137 ctx->timestamp = now;
1140 static u64 perf_event_time(struct perf_event *event)
1142 struct perf_event_context *ctx = event->ctx;
1144 if (is_cgroup_event(event))
1145 return perf_cgroup_event_time(event);
1147 return ctx ? ctx->time : 0;
1151 * Update the total_time_enabled and total_time_running fields for a event.
1152 * The caller of this function needs to hold the ctx->lock.
1154 static void update_event_times(struct perf_event *event)
1156 struct perf_event_context *ctx = event->ctx;
1159 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1160 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1163 * in cgroup mode, time_enabled represents
1164 * the time the event was enabled AND active
1165 * tasks were in the monitored cgroup. This is
1166 * independent of the activity of the context as
1167 * there may be a mix of cgroup and non-cgroup events.
1169 * That is why we treat cgroup events differently
1172 if (is_cgroup_event(event))
1173 run_end = perf_cgroup_event_time(event);
1174 else if (ctx->is_active)
1175 run_end = ctx->time;
1177 run_end = event->tstamp_stopped;
1179 event->total_time_enabled = run_end - event->tstamp_enabled;
1181 if (event->state == PERF_EVENT_STATE_INACTIVE)
1182 run_end = event->tstamp_stopped;
1184 run_end = perf_event_time(event);
1186 event->total_time_running = run_end - event->tstamp_running;
1191 * Update total_time_enabled and total_time_running for all events in a group.
1193 static void update_group_times(struct perf_event *leader)
1195 struct perf_event *event;
1197 update_event_times(leader);
1198 list_for_each_entry(event, &leader->sibling_list, group_entry)
1199 update_event_times(event);
1202 static struct list_head *
1203 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1205 if (event->attr.pinned)
1206 return &ctx->pinned_groups;
1208 return &ctx->flexible_groups;
1212 * Add a event from the lists for its context.
1213 * Must be called with ctx->mutex and ctx->lock held.
1216 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1218 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1219 event->attach_state |= PERF_ATTACH_CONTEXT;
1222 * If we're a stand alone event or group leader, we go to the context
1223 * list, group events are kept attached to the group so that
1224 * perf_group_detach can, at all times, locate all siblings.
1226 if (event->group_leader == event) {
1227 struct list_head *list;
1229 if (is_software_event(event))
1230 event->group_flags |= PERF_GROUP_SOFTWARE;
1232 list = ctx_group_list(event, ctx);
1233 list_add_tail(&event->group_entry, list);
1236 if (is_cgroup_event(event))
1239 list_add_rcu(&event->event_entry, &ctx->event_list);
1241 if (event->attr.inherit_stat)
1248 * Initialize event state based on the perf_event_attr::disabled.
1250 static inline void perf_event__state_init(struct perf_event *event)
1252 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1253 PERF_EVENT_STATE_INACTIVE;
1256 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1258 int entry = sizeof(u64); /* value */
1262 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1263 size += sizeof(u64);
1265 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1266 size += sizeof(u64);
1268 if (event->attr.read_format & PERF_FORMAT_ID)
1269 entry += sizeof(u64);
1271 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1273 size += sizeof(u64);
1277 event->read_size = size;
1280 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1282 struct perf_sample_data *data;
1285 if (sample_type & PERF_SAMPLE_IP)
1286 size += sizeof(data->ip);
1288 if (sample_type & PERF_SAMPLE_ADDR)
1289 size += sizeof(data->addr);
1291 if (sample_type & PERF_SAMPLE_PERIOD)
1292 size += sizeof(data->period);
1294 if (sample_type & PERF_SAMPLE_WEIGHT)
1295 size += sizeof(data->weight);
1297 if (sample_type & PERF_SAMPLE_READ)
1298 size += event->read_size;
1300 if (sample_type & PERF_SAMPLE_DATA_SRC)
1301 size += sizeof(data->data_src.val);
1303 if (sample_type & PERF_SAMPLE_TRANSACTION)
1304 size += sizeof(data->txn);
1306 event->header_size = size;
1310 * Called at perf_event creation and when events are attached/detached from a
1313 static void perf_event__header_size(struct perf_event *event)
1315 __perf_event_read_size(event,
1316 event->group_leader->nr_siblings);
1317 __perf_event_header_size(event, event->attr.sample_type);
1320 static void perf_event__id_header_size(struct perf_event *event)
1322 struct perf_sample_data *data;
1323 u64 sample_type = event->attr.sample_type;
1326 if (sample_type & PERF_SAMPLE_TID)
1327 size += sizeof(data->tid_entry);
1329 if (sample_type & PERF_SAMPLE_TIME)
1330 size += sizeof(data->time);
1332 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1333 size += sizeof(data->id);
1335 if (sample_type & PERF_SAMPLE_ID)
1336 size += sizeof(data->id);
1338 if (sample_type & PERF_SAMPLE_STREAM_ID)
1339 size += sizeof(data->stream_id);
1341 if (sample_type & PERF_SAMPLE_CPU)
1342 size += sizeof(data->cpu_entry);
1344 event->id_header_size = size;
1347 static bool perf_event_validate_size(struct perf_event *event)
1350 * The values computed here will be over-written when we actually
1353 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1354 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1355 perf_event__id_header_size(event);
1358 * Sum the lot; should not exceed the 64k limit we have on records.
1359 * Conservative limit to allow for callchains and other variable fields.
1361 if (event->read_size + event->header_size +
1362 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1368 static void perf_group_attach(struct perf_event *event)
1370 struct perf_event *group_leader = event->group_leader, *pos;
1373 * We can have double attach due to group movement in perf_event_open.
1375 if (event->attach_state & PERF_ATTACH_GROUP)
1378 event->attach_state |= PERF_ATTACH_GROUP;
1380 if (group_leader == event)
1383 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1385 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
1386 !is_software_event(event))
1387 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
1389 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1390 group_leader->nr_siblings++;
1392 perf_event__header_size(group_leader);
1394 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1395 perf_event__header_size(pos);
1399 * Remove a event from the lists for its context.
1400 * Must be called with ctx->mutex and ctx->lock held.
1403 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1405 struct perf_cpu_context *cpuctx;
1407 WARN_ON_ONCE(event->ctx != ctx);
1408 lockdep_assert_held(&ctx->lock);
1411 * We can have double detach due to exit/hot-unplug + close.
1413 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1416 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1418 if (is_cgroup_event(event)) {
1420 cpuctx = __get_cpu_context(ctx);
1422 * if there are no more cgroup events
1423 * then cler cgrp to avoid stale pointer
1424 * in update_cgrp_time_from_cpuctx()
1426 if (!ctx->nr_cgroups)
1427 cpuctx->cgrp = NULL;
1431 if (event->attr.inherit_stat)
1434 list_del_rcu(&event->event_entry);
1436 if (event->group_leader == event)
1437 list_del_init(&event->group_entry);
1439 update_group_times(event);
1442 * If event was in error state, then keep it
1443 * that way, otherwise bogus counts will be
1444 * returned on read(). The only way to get out
1445 * of error state is by explicit re-enabling
1448 if (event->state > PERF_EVENT_STATE_OFF)
1449 event->state = PERF_EVENT_STATE_OFF;
1454 static void perf_group_detach(struct perf_event *event)
1456 struct perf_event *sibling, *tmp;
1457 struct list_head *list = NULL;
1460 * We can have double detach due to exit/hot-unplug + close.
1462 if (!(event->attach_state & PERF_ATTACH_GROUP))
1465 event->attach_state &= ~PERF_ATTACH_GROUP;
1468 * If this is a sibling, remove it from its group.
1470 if (event->group_leader != event) {
1471 list_del_init(&event->group_entry);
1472 event->group_leader->nr_siblings--;
1476 if (!list_empty(&event->group_entry))
1477 list = &event->group_entry;
1480 * If this was a group event with sibling events then
1481 * upgrade the siblings to singleton events by adding them
1482 * to whatever list we are on.
1484 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1486 list_move_tail(&sibling->group_entry, list);
1487 sibling->group_leader = sibling;
1489 /* Inherit group flags from the previous leader */
1490 sibling->group_flags = event->group_flags;
1492 WARN_ON_ONCE(sibling->ctx != event->ctx);
1496 perf_event__header_size(event->group_leader);
1498 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1499 perf_event__header_size(tmp);
1503 * User event without the task.
1505 static bool is_orphaned_event(struct perf_event *event)
1507 return event && !is_kernel_event(event) && !event->owner;
1511 * Event has a parent but parent's task finished and it's
1512 * alive only because of children holding refference.
1514 static bool is_orphaned_child(struct perf_event *event)
1516 return is_orphaned_event(event->parent);
1519 static void orphans_remove_work(struct work_struct *work);
1521 static void schedule_orphans_remove(struct perf_event_context *ctx)
1523 if (!ctx->task || ctx->orphans_remove_sched || !perf_wq)
1526 if (queue_delayed_work(perf_wq, &ctx->orphans_remove, 1)) {
1528 ctx->orphans_remove_sched = true;
1532 static int __init perf_workqueue_init(void)
1534 perf_wq = create_singlethread_workqueue("perf");
1535 WARN(!perf_wq, "failed to create perf workqueue\n");
1536 return perf_wq ? 0 : -1;
1539 core_initcall(perf_workqueue_init);
1541 static inline int pmu_filter_match(struct perf_event *event)
1543 struct pmu *pmu = event->pmu;
1544 return pmu->filter_match ? pmu->filter_match(event) : 1;
1548 event_filter_match(struct perf_event *event)
1550 return (event->cpu == -1 || event->cpu == smp_processor_id())
1551 && perf_cgroup_match(event) && pmu_filter_match(event);
1555 event_sched_out(struct perf_event *event,
1556 struct perf_cpu_context *cpuctx,
1557 struct perf_event_context *ctx)
1559 u64 tstamp = perf_event_time(event);
1562 WARN_ON_ONCE(event->ctx != ctx);
1563 lockdep_assert_held(&ctx->lock);
1566 * An event which could not be activated because of
1567 * filter mismatch still needs to have its timings
1568 * maintained, otherwise bogus information is return
1569 * via read() for time_enabled, time_running:
1571 if (event->state == PERF_EVENT_STATE_INACTIVE
1572 && !event_filter_match(event)) {
1573 delta = tstamp - event->tstamp_stopped;
1574 event->tstamp_running += delta;
1575 event->tstamp_stopped = tstamp;
1578 if (event->state != PERF_EVENT_STATE_ACTIVE)
1581 perf_pmu_disable(event->pmu);
1583 event->state = PERF_EVENT_STATE_INACTIVE;
1584 if (event->pending_disable) {
1585 event->pending_disable = 0;
1586 event->state = PERF_EVENT_STATE_OFF;
1588 event->tstamp_stopped = tstamp;
1589 event->pmu->del(event, 0);
1592 if (!is_software_event(event))
1593 cpuctx->active_oncpu--;
1594 if (!--ctx->nr_active)
1595 perf_event_ctx_deactivate(ctx);
1596 if (event->attr.freq && event->attr.sample_freq)
1598 if (event->attr.exclusive || !cpuctx->active_oncpu)
1599 cpuctx->exclusive = 0;
1601 if (is_orphaned_child(event))
1602 schedule_orphans_remove(ctx);
1604 perf_pmu_enable(event->pmu);
1608 group_sched_out(struct perf_event *group_event,
1609 struct perf_cpu_context *cpuctx,
1610 struct perf_event_context *ctx)
1612 struct perf_event *event;
1613 int state = group_event->state;
1615 event_sched_out(group_event, cpuctx, ctx);
1618 * Schedule out siblings (if any):
1620 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1621 event_sched_out(event, cpuctx, ctx);
1623 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1624 cpuctx->exclusive = 0;
1627 struct remove_event {
1628 struct perf_event *event;
1633 * Cross CPU call to remove a performance event
1635 * We disable the event on the hardware level first. After that we
1636 * remove it from the context list.
1638 static int __perf_remove_from_context(void *info)
1640 struct remove_event *re = info;
1641 struct perf_event *event = re->event;
1642 struct perf_event_context *ctx = event->ctx;
1643 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1645 raw_spin_lock(&ctx->lock);
1646 event_sched_out(event, cpuctx, ctx);
1647 if (re->detach_group)
1648 perf_group_detach(event);
1649 list_del_event(event, ctx);
1650 if (!ctx->nr_events && cpuctx->task_ctx == ctx) {
1652 cpuctx->task_ctx = NULL;
1654 raw_spin_unlock(&ctx->lock);
1661 * Remove the event from a task's (or a CPU's) list of events.
1663 * CPU events are removed with a smp call. For task events we only
1664 * call when the task is on a CPU.
1666 * If event->ctx is a cloned context, callers must make sure that
1667 * every task struct that event->ctx->task could possibly point to
1668 * remains valid. This is OK when called from perf_release since
1669 * that only calls us on the top-level context, which can't be a clone.
1670 * When called from perf_event_exit_task, it's OK because the
1671 * context has been detached from its task.
1673 static void perf_remove_from_context(struct perf_event *event, bool detach_group)
1675 struct perf_event_context *ctx = event->ctx;
1676 struct task_struct *task = ctx->task;
1677 struct remove_event re = {
1679 .detach_group = detach_group,
1682 lockdep_assert_held(&ctx->mutex);
1686 * Per cpu events are removed via an smp call. The removal can
1687 * fail if the CPU is currently offline, but in that case we
1688 * already called __perf_remove_from_context from
1689 * perf_event_exit_cpu.
1691 cpu_function_call(event->cpu, __perf_remove_from_context, &re);
1696 if (!task_function_call(task, __perf_remove_from_context, &re))
1699 raw_spin_lock_irq(&ctx->lock);
1701 * If we failed to find a running task, but find the context active now
1702 * that we've acquired the ctx->lock, retry.
1704 if (ctx->is_active) {
1705 raw_spin_unlock_irq(&ctx->lock);
1707 * Reload the task pointer, it might have been changed by
1708 * a concurrent perf_event_context_sched_out().
1715 * Since the task isn't running, its safe to remove the event, us
1716 * holding the ctx->lock ensures the task won't get scheduled in.
1719 perf_group_detach(event);
1720 list_del_event(event, ctx);
1721 raw_spin_unlock_irq(&ctx->lock);
1725 * Cross CPU call to disable a performance event
1727 int __perf_event_disable(void *info)
1729 struct perf_event *event = info;
1730 struct perf_event_context *ctx = event->ctx;
1731 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1734 * If this is a per-task event, need to check whether this
1735 * event's task is the current task on this cpu.
1737 * Can trigger due to concurrent perf_event_context_sched_out()
1738 * flipping contexts around.
1740 if (ctx->task && cpuctx->task_ctx != ctx)
1743 raw_spin_lock(&ctx->lock);
1746 * If the event is on, turn it off.
1747 * If it is in error state, leave it in error state.
1749 if (event->state >= PERF_EVENT_STATE_INACTIVE) {
1750 update_context_time(ctx);
1751 update_cgrp_time_from_event(event);
1752 update_group_times(event);
1753 if (event == event->group_leader)
1754 group_sched_out(event, cpuctx, ctx);
1756 event_sched_out(event, cpuctx, ctx);
1757 event->state = PERF_EVENT_STATE_OFF;
1760 raw_spin_unlock(&ctx->lock);
1768 * If event->ctx is a cloned context, callers must make sure that
1769 * every task struct that event->ctx->task could possibly point to
1770 * remains valid. This condition is satisifed when called through
1771 * perf_event_for_each_child or perf_event_for_each because they
1772 * hold the top-level event's child_mutex, so any descendant that
1773 * goes to exit will block in sync_child_event.
1774 * When called from perf_pending_event it's OK because event->ctx
1775 * is the current context on this CPU and preemption is disabled,
1776 * hence we can't get into perf_event_task_sched_out for this context.
1778 static void _perf_event_disable(struct perf_event *event)
1780 struct perf_event_context *ctx = event->ctx;
1781 struct task_struct *task = ctx->task;
1785 * Disable the event on the cpu that it's on
1787 cpu_function_call(event->cpu, __perf_event_disable, event);
1792 if (!task_function_call(task, __perf_event_disable, event))
1795 raw_spin_lock_irq(&ctx->lock);
1797 * If the event is still active, we need to retry the cross-call.
1799 if (event->state == PERF_EVENT_STATE_ACTIVE) {
1800 raw_spin_unlock_irq(&ctx->lock);
1802 * Reload the task pointer, it might have been changed by
1803 * a concurrent perf_event_context_sched_out().
1810 * Since we have the lock this context can't be scheduled
1811 * in, so we can change the state safely.
1813 if (event->state == PERF_EVENT_STATE_INACTIVE) {
1814 update_group_times(event);
1815 event->state = PERF_EVENT_STATE_OFF;
1817 raw_spin_unlock_irq(&ctx->lock);
1821 * Strictly speaking kernel users cannot create groups and therefore this
1822 * interface does not need the perf_event_ctx_lock() magic.
1824 void perf_event_disable(struct perf_event *event)
1826 struct perf_event_context *ctx;
1828 ctx = perf_event_ctx_lock(event);
1829 _perf_event_disable(event);
1830 perf_event_ctx_unlock(event, ctx);
1832 EXPORT_SYMBOL_GPL(perf_event_disable);
1834 static void perf_set_shadow_time(struct perf_event *event,
1835 struct perf_event_context *ctx,
1839 * use the correct time source for the time snapshot
1841 * We could get by without this by leveraging the
1842 * fact that to get to this function, the caller
1843 * has most likely already called update_context_time()
1844 * and update_cgrp_time_xx() and thus both timestamp
1845 * are identical (or very close). Given that tstamp is,
1846 * already adjusted for cgroup, we could say that:
1847 * tstamp - ctx->timestamp
1849 * tstamp - cgrp->timestamp.
1851 * Then, in perf_output_read(), the calculation would
1852 * work with no changes because:
1853 * - event is guaranteed scheduled in
1854 * - no scheduled out in between
1855 * - thus the timestamp would be the same
1857 * But this is a bit hairy.
1859 * So instead, we have an explicit cgroup call to remain
1860 * within the time time source all along. We believe it
1861 * is cleaner and simpler to understand.
1863 if (is_cgroup_event(event))
1864 perf_cgroup_set_shadow_time(event, tstamp);
1866 event->shadow_ctx_time = tstamp - ctx->timestamp;
1869 #define MAX_INTERRUPTS (~0ULL)
1871 static void perf_log_throttle(struct perf_event *event, int enable);
1872 static void perf_log_itrace_start(struct perf_event *event);
1875 event_sched_in(struct perf_event *event,
1876 struct perf_cpu_context *cpuctx,
1877 struct perf_event_context *ctx)
1879 u64 tstamp = perf_event_time(event);
1882 lockdep_assert_held(&ctx->lock);
1884 if (event->state <= PERF_EVENT_STATE_OFF)
1887 event->state = PERF_EVENT_STATE_ACTIVE;
1888 event->oncpu = smp_processor_id();
1891 * Unthrottle events, since we scheduled we might have missed several
1892 * ticks already, also for a heavily scheduling task there is little
1893 * guarantee it'll get a tick in a timely manner.
1895 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1896 perf_log_throttle(event, 1);
1897 event->hw.interrupts = 0;
1901 * The new state must be visible before we turn it on in the hardware:
1905 perf_pmu_disable(event->pmu);
1907 perf_set_shadow_time(event, ctx, tstamp);
1909 perf_log_itrace_start(event);
1911 if (event->pmu->add(event, PERF_EF_START)) {
1912 event->state = PERF_EVENT_STATE_INACTIVE;
1918 event->tstamp_running += tstamp - event->tstamp_stopped;
1920 if (!is_software_event(event))
1921 cpuctx->active_oncpu++;
1922 if (!ctx->nr_active++)
1923 perf_event_ctx_activate(ctx);
1924 if (event->attr.freq && event->attr.sample_freq)
1927 if (event->attr.exclusive)
1928 cpuctx->exclusive = 1;
1930 if (is_orphaned_child(event))
1931 schedule_orphans_remove(ctx);
1934 perf_pmu_enable(event->pmu);
1940 group_sched_in(struct perf_event *group_event,
1941 struct perf_cpu_context *cpuctx,
1942 struct perf_event_context *ctx)
1944 struct perf_event *event, *partial_group = NULL;
1945 struct pmu *pmu = ctx->pmu;
1946 u64 now = ctx->time;
1947 bool simulate = false;
1949 if (group_event->state == PERF_EVENT_STATE_OFF)
1952 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
1954 if (event_sched_in(group_event, cpuctx, ctx)) {
1955 pmu->cancel_txn(pmu);
1956 perf_mux_hrtimer_restart(cpuctx);
1961 * Schedule in siblings as one group (if any):
1963 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1964 if (event_sched_in(event, cpuctx, ctx)) {
1965 partial_group = event;
1970 if (!pmu->commit_txn(pmu))
1975 * Groups can be scheduled in as one unit only, so undo any
1976 * partial group before returning:
1977 * The events up to the failed event are scheduled out normally,
1978 * tstamp_stopped will be updated.
1980 * The failed events and the remaining siblings need to have
1981 * their timings updated as if they had gone thru event_sched_in()
1982 * and event_sched_out(). This is required to get consistent timings
1983 * across the group. This also takes care of the case where the group
1984 * could never be scheduled by ensuring tstamp_stopped is set to mark
1985 * the time the event was actually stopped, such that time delta
1986 * calculation in update_event_times() is correct.
1988 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1989 if (event == partial_group)
1993 event->tstamp_running += now - event->tstamp_stopped;
1994 event->tstamp_stopped = now;
1996 event_sched_out(event, cpuctx, ctx);
1999 event_sched_out(group_event, cpuctx, ctx);
2001 pmu->cancel_txn(pmu);
2003 perf_mux_hrtimer_restart(cpuctx);
2009 * Work out whether we can put this event group on the CPU now.
2011 static int group_can_go_on(struct perf_event *event,
2012 struct perf_cpu_context *cpuctx,
2016 * Groups consisting entirely of software events can always go on.
2018 if (event->group_flags & PERF_GROUP_SOFTWARE)
2021 * If an exclusive group is already on, no other hardware
2024 if (cpuctx->exclusive)
2027 * If this group is exclusive and there are already
2028 * events on the CPU, it can't go on.
2030 if (event->attr.exclusive && cpuctx->active_oncpu)
2033 * Otherwise, try to add it if all previous groups were able
2039 static void add_event_to_ctx(struct perf_event *event,
2040 struct perf_event_context *ctx)
2042 u64 tstamp = perf_event_time(event);
2044 list_add_event(event, ctx);
2045 perf_group_attach(event);
2046 event->tstamp_enabled = tstamp;
2047 event->tstamp_running = tstamp;
2048 event->tstamp_stopped = tstamp;
2051 static void task_ctx_sched_out(struct perf_event_context *ctx);
2053 ctx_sched_in(struct perf_event_context *ctx,
2054 struct perf_cpu_context *cpuctx,
2055 enum event_type_t event_type,
2056 struct task_struct *task);
2058 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2059 struct perf_event_context *ctx,
2060 struct task_struct *task)
2062 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2064 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2065 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2067 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2071 * Cross CPU call to install and enable a performance event
2073 * Must be called with ctx->mutex held
2075 static int __perf_install_in_context(void *info)
2077 struct perf_event *event = info;
2078 struct perf_event_context *ctx = event->ctx;
2079 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2080 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2081 struct task_struct *task = current;
2083 perf_ctx_lock(cpuctx, task_ctx);
2084 perf_pmu_disable(cpuctx->ctx.pmu);
2087 * If there was an active task_ctx schedule it out.
2090 task_ctx_sched_out(task_ctx);
2093 * If the context we're installing events in is not the
2094 * active task_ctx, flip them.
2096 if (ctx->task && task_ctx != ctx) {
2098 raw_spin_unlock(&task_ctx->lock);
2099 raw_spin_lock(&ctx->lock);
2104 cpuctx->task_ctx = task_ctx;
2105 task = task_ctx->task;
2108 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
2110 update_context_time(ctx);
2112 * update cgrp time only if current cgrp
2113 * matches event->cgrp. Must be done before
2114 * calling add_event_to_ctx()
2116 update_cgrp_time_from_event(event);
2118 add_event_to_ctx(event, ctx);
2121 * Schedule everything back in
2123 perf_event_sched_in(cpuctx, task_ctx, task);
2125 perf_pmu_enable(cpuctx->ctx.pmu);
2126 perf_ctx_unlock(cpuctx, task_ctx);
2132 * Attach a performance event to a context
2134 * First we add the event to the list with the hardware enable bit
2135 * in event->hw_config cleared.
2137 * If the event is attached to a task which is on a CPU we use a smp
2138 * call to enable it in the task context. The task might have been
2139 * scheduled away, but we check this in the smp call again.
2142 perf_install_in_context(struct perf_event_context *ctx,
2143 struct perf_event *event,
2146 struct task_struct *task = ctx->task;
2148 lockdep_assert_held(&ctx->mutex);
2151 if (event->cpu != -1)
2156 * Per cpu events are installed via an smp call and
2157 * the install is always successful.
2159 cpu_function_call(cpu, __perf_install_in_context, event);
2164 if (!task_function_call(task, __perf_install_in_context, event))
2167 raw_spin_lock_irq(&ctx->lock);
2169 * If we failed to find a running task, but find the context active now
2170 * that we've acquired the ctx->lock, retry.
2172 if (ctx->is_active) {
2173 raw_spin_unlock_irq(&ctx->lock);
2175 * Reload the task pointer, it might have been changed by
2176 * a concurrent perf_event_context_sched_out().
2183 * Since the task isn't running, its safe to add the event, us holding
2184 * the ctx->lock ensures the task won't get scheduled in.
2186 add_event_to_ctx(event, ctx);
2187 raw_spin_unlock_irq(&ctx->lock);
2191 * Put a event into inactive state and update time fields.
2192 * Enabling the leader of a group effectively enables all
2193 * the group members that aren't explicitly disabled, so we
2194 * have to update their ->tstamp_enabled also.
2195 * Note: this works for group members as well as group leaders
2196 * since the non-leader members' sibling_lists will be empty.
2198 static void __perf_event_mark_enabled(struct perf_event *event)
2200 struct perf_event *sub;
2201 u64 tstamp = perf_event_time(event);
2203 event->state = PERF_EVENT_STATE_INACTIVE;
2204 event->tstamp_enabled = tstamp - event->total_time_enabled;
2205 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2206 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2207 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2212 * Cross CPU call to enable a performance event
2214 static int __perf_event_enable(void *info)
2216 struct perf_event *event = info;
2217 struct perf_event_context *ctx = event->ctx;
2218 struct perf_event *leader = event->group_leader;
2219 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2223 * There's a time window between 'ctx->is_active' check
2224 * in perf_event_enable function and this place having:
2226 * - ctx->lock unlocked
2228 * where the task could be killed and 'ctx' deactivated
2229 * by perf_event_exit_task.
2231 if (!ctx->is_active)
2234 raw_spin_lock(&ctx->lock);
2235 update_context_time(ctx);
2237 if (event->state >= PERF_EVENT_STATE_INACTIVE)
2241 * set current task's cgroup time reference point
2243 perf_cgroup_set_timestamp(current, ctx);
2245 __perf_event_mark_enabled(event);
2247 if (!event_filter_match(event)) {
2248 if (is_cgroup_event(event))
2249 perf_cgroup_defer_enabled(event);
2254 * If the event is in a group and isn't the group leader,
2255 * then don't put it on unless the group is on.
2257 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
2260 if (!group_can_go_on(event, cpuctx, 1)) {
2263 if (event == leader)
2264 err = group_sched_in(event, cpuctx, ctx);
2266 err = event_sched_in(event, cpuctx, ctx);
2271 * If this event can't go on and it's part of a
2272 * group, then the whole group has to come off.
2274 if (leader != event) {
2275 group_sched_out(leader, cpuctx, ctx);
2276 perf_mux_hrtimer_restart(cpuctx);
2278 if (leader->attr.pinned) {
2279 update_group_times(leader);
2280 leader->state = PERF_EVENT_STATE_ERROR;
2285 raw_spin_unlock(&ctx->lock);
2293 * If event->ctx is a cloned context, callers must make sure that
2294 * every task struct that event->ctx->task could possibly point to
2295 * remains valid. This condition is satisfied when called through
2296 * perf_event_for_each_child or perf_event_for_each as described
2297 * for perf_event_disable.
2299 static void _perf_event_enable(struct perf_event *event)
2301 struct perf_event_context *ctx = event->ctx;
2302 struct task_struct *task = ctx->task;
2306 * Enable the event on the cpu that it's on
2308 cpu_function_call(event->cpu, __perf_event_enable, event);
2312 raw_spin_lock_irq(&ctx->lock);
2313 if (event->state >= PERF_EVENT_STATE_INACTIVE)
2317 * If the event is in error state, clear that first.
2318 * That way, if we see the event in error state below, we
2319 * know that it has gone back into error state, as distinct
2320 * from the task having been scheduled away before the
2321 * cross-call arrived.
2323 if (event->state == PERF_EVENT_STATE_ERROR)
2324 event->state = PERF_EVENT_STATE_OFF;
2327 if (!ctx->is_active) {
2328 __perf_event_mark_enabled(event);
2332 raw_spin_unlock_irq(&ctx->lock);
2334 if (!task_function_call(task, __perf_event_enable, event))
2337 raw_spin_lock_irq(&ctx->lock);
2340 * If the context is active and the event is still off,
2341 * we need to retry the cross-call.
2343 if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) {
2345 * task could have been flipped by a concurrent
2346 * perf_event_context_sched_out()
2353 raw_spin_unlock_irq(&ctx->lock);
2357 * See perf_event_disable();
2359 void perf_event_enable(struct perf_event *event)
2361 struct perf_event_context *ctx;
2363 ctx = perf_event_ctx_lock(event);
2364 _perf_event_enable(event);
2365 perf_event_ctx_unlock(event, ctx);
2367 EXPORT_SYMBOL_GPL(perf_event_enable);
2369 static int _perf_event_refresh(struct perf_event *event, int refresh)
2372 * not supported on inherited events
2374 if (event->attr.inherit || !is_sampling_event(event))
2377 atomic_add(refresh, &event->event_limit);
2378 _perf_event_enable(event);
2384 * See perf_event_disable()
2386 int perf_event_refresh(struct perf_event *event, int refresh)
2388 struct perf_event_context *ctx;
2391 ctx = perf_event_ctx_lock(event);
2392 ret = _perf_event_refresh(event, refresh);
2393 perf_event_ctx_unlock(event, ctx);
2397 EXPORT_SYMBOL_GPL(perf_event_refresh);
2399 static void ctx_sched_out(struct perf_event_context *ctx,
2400 struct perf_cpu_context *cpuctx,
2401 enum event_type_t event_type)
2403 struct perf_event *event;
2404 int is_active = ctx->is_active;
2406 ctx->is_active &= ~event_type;
2407 if (likely(!ctx->nr_events))
2410 update_context_time(ctx);
2411 update_cgrp_time_from_cpuctx(cpuctx);
2412 if (!ctx->nr_active)
2415 perf_pmu_disable(ctx->pmu);
2416 if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) {
2417 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2418 group_sched_out(event, cpuctx, ctx);
2421 if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) {
2422 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2423 group_sched_out(event, cpuctx, ctx);
2425 perf_pmu_enable(ctx->pmu);
2429 * Test whether two contexts are equivalent, i.e. whether they have both been
2430 * cloned from the same version of the same context.
2432 * Equivalence is measured using a generation number in the context that is
2433 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2434 * and list_del_event().
2436 static int context_equiv(struct perf_event_context *ctx1,
2437 struct perf_event_context *ctx2)
2439 lockdep_assert_held(&ctx1->lock);
2440 lockdep_assert_held(&ctx2->lock);
2442 /* Pinning disables the swap optimization */
2443 if (ctx1->pin_count || ctx2->pin_count)
2446 /* If ctx1 is the parent of ctx2 */
2447 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2450 /* If ctx2 is the parent of ctx1 */
2451 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2455 * If ctx1 and ctx2 have the same parent; we flatten the parent
2456 * hierarchy, see perf_event_init_context().
2458 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2459 ctx1->parent_gen == ctx2->parent_gen)
2466 static void __perf_event_sync_stat(struct perf_event *event,
2467 struct perf_event *next_event)
2471 if (!event->attr.inherit_stat)
2475 * Update the event value, we cannot use perf_event_read()
2476 * because we're in the middle of a context switch and have IRQs
2477 * disabled, which upsets smp_call_function_single(), however
2478 * we know the event must be on the current CPU, therefore we
2479 * don't need to use it.
2481 switch (event->state) {
2482 case PERF_EVENT_STATE_ACTIVE:
2483 event->pmu->read(event);
2486 case PERF_EVENT_STATE_INACTIVE:
2487 update_event_times(event);
2495 * In order to keep per-task stats reliable we need to flip the event
2496 * values when we flip the contexts.
2498 value = local64_read(&next_event->count);
2499 value = local64_xchg(&event->count, value);
2500 local64_set(&next_event->count, value);
2502 swap(event->total_time_enabled, next_event->total_time_enabled);
2503 swap(event->total_time_running, next_event->total_time_running);
2506 * Since we swizzled the values, update the user visible data too.
2508 perf_event_update_userpage(event);
2509 perf_event_update_userpage(next_event);
2512 static void perf_event_sync_stat(struct perf_event_context *ctx,
2513 struct perf_event_context *next_ctx)
2515 struct perf_event *event, *next_event;
2520 update_context_time(ctx);
2522 event = list_first_entry(&ctx->event_list,
2523 struct perf_event, event_entry);
2525 next_event = list_first_entry(&next_ctx->event_list,
2526 struct perf_event, event_entry);
2528 while (&event->event_entry != &ctx->event_list &&
2529 &next_event->event_entry != &next_ctx->event_list) {
2531 __perf_event_sync_stat(event, next_event);
2533 event = list_next_entry(event, event_entry);
2534 next_event = list_next_entry(next_event, event_entry);
2538 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2539 struct task_struct *next)
2541 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2542 struct perf_event_context *next_ctx;
2543 struct perf_event_context *parent, *next_parent;
2544 struct perf_cpu_context *cpuctx;
2550 cpuctx = __get_cpu_context(ctx);
2551 if (!cpuctx->task_ctx)
2555 next_ctx = next->perf_event_ctxp[ctxn];
2559 parent = rcu_dereference(ctx->parent_ctx);
2560 next_parent = rcu_dereference(next_ctx->parent_ctx);
2562 /* If neither context have a parent context; they cannot be clones. */
2563 if (!parent && !next_parent)
2566 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2568 * Looks like the two contexts are clones, so we might be
2569 * able to optimize the context switch. We lock both
2570 * contexts and check that they are clones under the
2571 * lock (including re-checking that neither has been
2572 * uncloned in the meantime). It doesn't matter which
2573 * order we take the locks because no other cpu could
2574 * be trying to lock both of these tasks.
2576 raw_spin_lock(&ctx->lock);
2577 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2578 if (context_equiv(ctx, next_ctx)) {
2580 * XXX do we need a memory barrier of sorts
2581 * wrt to rcu_dereference() of perf_event_ctxp
2583 task->perf_event_ctxp[ctxn] = next_ctx;
2584 next->perf_event_ctxp[ctxn] = ctx;
2586 next_ctx->task = task;
2588 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2592 perf_event_sync_stat(ctx, next_ctx);
2594 raw_spin_unlock(&next_ctx->lock);
2595 raw_spin_unlock(&ctx->lock);
2601 raw_spin_lock(&ctx->lock);
2602 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2603 cpuctx->task_ctx = NULL;
2604 raw_spin_unlock(&ctx->lock);
2608 void perf_sched_cb_dec(struct pmu *pmu)
2610 this_cpu_dec(perf_sched_cb_usages);
2613 void perf_sched_cb_inc(struct pmu *pmu)
2615 this_cpu_inc(perf_sched_cb_usages);
2619 * This function provides the context switch callback to the lower code
2620 * layer. It is invoked ONLY when the context switch callback is enabled.
2622 static void perf_pmu_sched_task(struct task_struct *prev,
2623 struct task_struct *next,
2626 struct perf_cpu_context *cpuctx;
2628 unsigned long flags;
2633 local_irq_save(flags);
2637 list_for_each_entry_rcu(pmu, &pmus, entry) {
2638 if (pmu->sched_task) {
2639 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2641 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2643 perf_pmu_disable(pmu);
2645 pmu->sched_task(cpuctx->task_ctx, sched_in);
2647 perf_pmu_enable(pmu);
2649 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2655 local_irq_restore(flags);
2658 static void perf_event_switch(struct task_struct *task,
2659 struct task_struct *next_prev, bool sched_in);
2661 #define for_each_task_context_nr(ctxn) \
2662 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2665 * Called from scheduler to remove the events of the current task,
2666 * with interrupts disabled.
2668 * We stop each event and update the event value in event->count.
2670 * This does not protect us against NMI, but disable()
2671 * sets the disabled bit in the control field of event _before_
2672 * accessing the event control register. If a NMI hits, then it will
2673 * not restart the event.
2675 void __perf_event_task_sched_out(struct task_struct *task,
2676 struct task_struct *next)
2680 if (__this_cpu_read(perf_sched_cb_usages))
2681 perf_pmu_sched_task(task, next, false);
2683 if (atomic_read(&nr_switch_events))
2684 perf_event_switch(task, next, false);
2686 for_each_task_context_nr(ctxn)
2687 perf_event_context_sched_out(task, ctxn, next);
2690 * if cgroup events exist on this CPU, then we need
2691 * to check if we have to switch out PMU state.
2692 * cgroup event are system-wide mode only
2694 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2695 perf_cgroup_sched_out(task, next);
2698 static void task_ctx_sched_out(struct perf_event_context *ctx)
2700 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2702 if (!cpuctx->task_ctx)
2705 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2708 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2709 cpuctx->task_ctx = NULL;
2713 * Called with IRQs disabled
2715 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2716 enum event_type_t event_type)
2718 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2722 ctx_pinned_sched_in(struct perf_event_context *ctx,
2723 struct perf_cpu_context *cpuctx)
2725 struct perf_event *event;
2727 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2728 if (event->state <= PERF_EVENT_STATE_OFF)
2730 if (!event_filter_match(event))
2733 /* may need to reset tstamp_enabled */
2734 if (is_cgroup_event(event))
2735 perf_cgroup_mark_enabled(event, ctx);
2737 if (group_can_go_on(event, cpuctx, 1))
2738 group_sched_in(event, cpuctx, ctx);
2741 * If this pinned group hasn't been scheduled,
2742 * put it in error state.
2744 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2745 update_group_times(event);
2746 event->state = PERF_EVENT_STATE_ERROR;
2752 ctx_flexible_sched_in(struct perf_event_context *ctx,
2753 struct perf_cpu_context *cpuctx)
2755 struct perf_event *event;
2758 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2759 /* Ignore events in OFF or ERROR state */
2760 if (event->state <= PERF_EVENT_STATE_OFF)
2763 * Listen to the 'cpu' scheduling filter constraint
2766 if (!event_filter_match(event))
2769 /* may need to reset tstamp_enabled */
2770 if (is_cgroup_event(event))
2771 perf_cgroup_mark_enabled(event, ctx);
2773 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2774 if (group_sched_in(event, cpuctx, ctx))
2781 ctx_sched_in(struct perf_event_context *ctx,
2782 struct perf_cpu_context *cpuctx,
2783 enum event_type_t event_type,
2784 struct task_struct *task)
2787 int is_active = ctx->is_active;
2789 ctx->is_active |= event_type;
2790 if (likely(!ctx->nr_events))
2794 ctx->timestamp = now;
2795 perf_cgroup_set_timestamp(task, ctx);
2797 * First go through the list and put on any pinned groups
2798 * in order to give them the best chance of going on.
2800 if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED))
2801 ctx_pinned_sched_in(ctx, cpuctx);
2803 /* Then walk through the lower prio flexible groups */
2804 if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE))
2805 ctx_flexible_sched_in(ctx, cpuctx);
2808 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2809 enum event_type_t event_type,
2810 struct task_struct *task)
2812 struct perf_event_context *ctx = &cpuctx->ctx;
2814 ctx_sched_in(ctx, cpuctx, event_type, task);
2817 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2818 struct task_struct *task)
2820 struct perf_cpu_context *cpuctx;
2822 cpuctx = __get_cpu_context(ctx);
2823 if (cpuctx->task_ctx == ctx)
2826 perf_ctx_lock(cpuctx, ctx);
2827 perf_pmu_disable(ctx->pmu);
2829 * We want to keep the following priority order:
2830 * cpu pinned (that don't need to move), task pinned,
2831 * cpu flexible, task flexible.
2833 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2836 cpuctx->task_ctx = ctx;
2838 perf_event_sched_in(cpuctx, cpuctx->task_ctx, task);
2840 perf_pmu_enable(ctx->pmu);
2841 perf_ctx_unlock(cpuctx, ctx);
2845 * Called from scheduler to add the events of the current task
2846 * with interrupts disabled.
2848 * We restore the event value and then enable it.
2850 * This does not protect us against NMI, but enable()
2851 * sets the enabled bit in the control field of event _before_
2852 * accessing the event control register. If a NMI hits, then it will
2853 * keep the event running.
2855 void __perf_event_task_sched_in(struct task_struct *prev,
2856 struct task_struct *task)
2858 struct perf_event_context *ctx;
2861 for_each_task_context_nr(ctxn) {
2862 ctx = task->perf_event_ctxp[ctxn];
2866 perf_event_context_sched_in(ctx, task);
2869 * if cgroup events exist on this CPU, then we need
2870 * to check if we have to switch in PMU state.
2871 * cgroup event are system-wide mode only
2873 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2874 perf_cgroup_sched_in(prev, task);
2876 if (atomic_read(&nr_switch_events))
2877 perf_event_switch(task, prev, true);
2879 if (__this_cpu_read(perf_sched_cb_usages))
2880 perf_pmu_sched_task(prev, task, true);
2883 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
2885 u64 frequency = event->attr.sample_freq;
2886 u64 sec = NSEC_PER_SEC;
2887 u64 divisor, dividend;
2889 int count_fls, nsec_fls, frequency_fls, sec_fls;
2891 count_fls = fls64(count);
2892 nsec_fls = fls64(nsec);
2893 frequency_fls = fls64(frequency);
2897 * We got @count in @nsec, with a target of sample_freq HZ
2898 * the target period becomes:
2901 * period = -------------------
2902 * @nsec * sample_freq
2907 * Reduce accuracy by one bit such that @a and @b converge
2908 * to a similar magnitude.
2910 #define REDUCE_FLS(a, b) \
2912 if (a##_fls > b##_fls) { \
2922 * Reduce accuracy until either term fits in a u64, then proceed with
2923 * the other, so that finally we can do a u64/u64 division.
2925 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
2926 REDUCE_FLS(nsec, frequency);
2927 REDUCE_FLS(sec, count);
2930 if (count_fls + sec_fls > 64) {
2931 divisor = nsec * frequency;
2933 while (count_fls + sec_fls > 64) {
2934 REDUCE_FLS(count, sec);
2938 dividend = count * sec;
2940 dividend = count * sec;
2942 while (nsec_fls + frequency_fls > 64) {
2943 REDUCE_FLS(nsec, frequency);
2947 divisor = nsec * frequency;
2953 return div64_u64(dividend, divisor);
2956 static DEFINE_PER_CPU(int, perf_throttled_count);
2957 static DEFINE_PER_CPU(u64, perf_throttled_seq);
2959 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
2961 struct hw_perf_event *hwc = &event->hw;
2962 s64 period, sample_period;
2965 period = perf_calculate_period(event, nsec, count);
2967 delta = (s64)(period - hwc->sample_period);
2968 delta = (delta + 7) / 8; /* low pass filter */
2970 sample_period = hwc->sample_period + delta;
2975 hwc->sample_period = sample_period;
2977 if (local64_read(&hwc->period_left) > 8*sample_period) {
2979 event->pmu->stop(event, PERF_EF_UPDATE);
2981 local64_set(&hwc->period_left, 0);
2984 event->pmu->start(event, PERF_EF_RELOAD);
2989 * combine freq adjustment with unthrottling to avoid two passes over the
2990 * events. At the same time, make sure, having freq events does not change
2991 * the rate of unthrottling as that would introduce bias.
2993 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
2996 struct perf_event *event;
2997 struct hw_perf_event *hwc;
2998 u64 now, period = TICK_NSEC;
3002 * only need to iterate over all events iff:
3003 * - context have events in frequency mode (needs freq adjust)
3004 * - there are events to unthrottle on this cpu
3006 if (!(ctx->nr_freq || needs_unthr))
3009 raw_spin_lock(&ctx->lock);
3010 perf_pmu_disable(ctx->pmu);
3012 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3013 if (event->state != PERF_EVENT_STATE_ACTIVE)
3016 if (!event_filter_match(event))
3019 perf_pmu_disable(event->pmu);
3023 if (hwc->interrupts == MAX_INTERRUPTS) {
3024 hwc->interrupts = 0;
3025 perf_log_throttle(event, 1);
3026 event->pmu->start(event, 0);
3029 if (!event->attr.freq || !event->attr.sample_freq)
3033 * stop the event and update event->count
3035 event->pmu->stop(event, PERF_EF_UPDATE);
3037 now = local64_read(&event->count);
3038 delta = now - hwc->freq_count_stamp;
3039 hwc->freq_count_stamp = now;
3043 * reload only if value has changed
3044 * we have stopped the event so tell that
3045 * to perf_adjust_period() to avoid stopping it
3049 perf_adjust_period(event, period, delta, false);
3051 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3053 perf_pmu_enable(event->pmu);
3056 perf_pmu_enable(ctx->pmu);
3057 raw_spin_unlock(&ctx->lock);
3061 * Round-robin a context's events:
3063 static void rotate_ctx(struct perf_event_context *ctx)
3066 * Rotate the first entry last of non-pinned groups. Rotation might be
3067 * disabled by the inheritance code.
3069 if (!ctx->rotate_disable)
3070 list_rotate_left(&ctx->flexible_groups);
3073 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3075 struct perf_event_context *ctx = NULL;
3078 if (cpuctx->ctx.nr_events) {
3079 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3083 ctx = cpuctx->task_ctx;
3084 if (ctx && ctx->nr_events) {
3085 if (ctx->nr_events != ctx->nr_active)
3092 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3093 perf_pmu_disable(cpuctx->ctx.pmu);
3095 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3097 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3099 rotate_ctx(&cpuctx->ctx);
3103 perf_event_sched_in(cpuctx, ctx, current);
3105 perf_pmu_enable(cpuctx->ctx.pmu);
3106 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3112 #ifdef CONFIG_NO_HZ_FULL
3113 bool perf_event_can_stop_tick(void)
3115 if (atomic_read(&nr_freq_events) ||
3116 __this_cpu_read(perf_throttled_count))
3123 void perf_event_task_tick(void)
3125 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3126 struct perf_event_context *ctx, *tmp;
3129 WARN_ON(!irqs_disabled());
3131 __this_cpu_inc(perf_throttled_seq);
3132 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3134 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3135 perf_adjust_freq_unthr_context(ctx, throttled);
3138 static int event_enable_on_exec(struct perf_event *event,
3139 struct perf_event_context *ctx)
3141 if (!event->attr.enable_on_exec)
3144 event->attr.enable_on_exec = 0;
3145 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3148 __perf_event_mark_enabled(event);
3154 * Enable all of a task's events that have been marked enable-on-exec.
3155 * This expects task == current.
3157 static void perf_event_enable_on_exec(int ctxn)
3159 struct perf_event_context *ctx, *clone_ctx = NULL;
3160 struct perf_event *event;
3161 unsigned long flags;
3165 local_irq_save(flags);
3166 ctx = current->perf_event_ctxp[ctxn];
3167 if (!ctx || !ctx->nr_events)
3171 * We must ctxsw out cgroup events to avoid conflict
3172 * when invoking perf_task_event_sched_in() later on
3173 * in this function. Otherwise we end up trying to
3174 * ctxswin cgroup events which are already scheduled
3177 perf_cgroup_sched_out(current, NULL);
3179 raw_spin_lock(&ctx->lock);
3180 task_ctx_sched_out(ctx);
3182 list_for_each_entry(event, &ctx->event_list, event_entry) {
3183 ret = event_enable_on_exec(event, ctx);
3189 * Unclone this context if we enabled any event.
3192 clone_ctx = unclone_ctx(ctx);
3194 raw_spin_unlock(&ctx->lock);
3197 * Also calls ctxswin for cgroup events, if any:
3199 perf_event_context_sched_in(ctx, ctx->task);
3201 local_irq_restore(flags);
3207 void perf_event_exec(void)
3212 for_each_task_context_nr(ctxn)
3213 perf_event_enable_on_exec(ctxn);
3217 struct perf_read_data {
3218 struct perf_event *event;
3224 * Cross CPU call to read the hardware event
3226 static void __perf_event_read(void *info)
3228 struct perf_read_data *data = info;
3229 struct perf_event *sub, *event = data->event;
3230 struct perf_event_context *ctx = event->ctx;
3231 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3232 struct pmu *pmu = event->pmu;
3235 * If this is a task context, we need to check whether it is
3236 * the current task context of this cpu. If not it has been
3237 * scheduled out before the smp call arrived. In that case
3238 * event->count would have been updated to a recent sample
3239 * when the event was scheduled out.
3241 if (ctx->task && cpuctx->task_ctx != ctx)
3244 raw_spin_lock(&ctx->lock);
3245 if (ctx->is_active) {
3246 update_context_time(ctx);
3247 update_cgrp_time_from_event(event);
3250 update_event_times(event);
3251 if (event->state != PERF_EVENT_STATE_ACTIVE)
3260 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3264 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3265 update_event_times(sub);
3266 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3268 * Use sibling's PMU rather than @event's since
3269 * sibling could be on different (eg: software) PMU.
3271 sub->pmu->read(sub);
3275 data->ret = pmu->commit_txn(pmu);
3278 raw_spin_unlock(&ctx->lock);
3281 static inline u64 perf_event_count(struct perf_event *event)
3283 if (event->pmu->count)
3284 return event->pmu->count(event);
3286 return __perf_event_count(event);
3290 * NMI-safe method to read a local event, that is an event that
3292 * - either for the current task, or for this CPU
3293 * - does not have inherit set, for inherited task events
3294 * will not be local and we cannot read them atomically
3295 * - must not have a pmu::count method
3297 u64 perf_event_read_local(struct perf_event *event)
3299 unsigned long flags;
3303 * Disabling interrupts avoids all counter scheduling (context
3304 * switches, timer based rotation and IPIs).
3306 local_irq_save(flags);
3308 /* If this is a per-task event, it must be for current */
3309 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3310 event->hw.target != current);
3312 /* If this is a per-CPU event, it must be for this CPU */
3313 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3314 event->cpu != smp_processor_id());
3317 * It must not be an event with inherit set, we cannot read
3318 * all child counters from atomic context.
3320 WARN_ON_ONCE(event->attr.inherit);
3323 * It must not have a pmu::count method, those are not
3326 WARN_ON_ONCE(event->pmu->count);
3329 * If the event is currently on this CPU, its either a per-task event,
3330 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3333 if (event->oncpu == smp_processor_id())
3334 event->pmu->read(event);
3336 val = local64_read(&event->count);
3337 local_irq_restore(flags);
3342 static int perf_event_read(struct perf_event *event, bool group)
3347 * If event is enabled and currently active on a CPU, update the
3348 * value in the event structure:
3350 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3351 struct perf_read_data data = {
3356 smp_call_function_single(event->oncpu,
3357 __perf_event_read, &data, 1);
3359 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3360 struct perf_event_context *ctx = event->ctx;
3361 unsigned long flags;
3363 raw_spin_lock_irqsave(&ctx->lock, flags);
3365 * may read while context is not active
3366 * (e.g., thread is blocked), in that case
3367 * we cannot update context time
3369 if (ctx->is_active) {
3370 update_context_time(ctx);
3371 update_cgrp_time_from_event(event);
3374 update_group_times(event);
3376 update_event_times(event);
3377 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3384 * Initialize the perf_event context in a task_struct:
3386 static void __perf_event_init_context(struct perf_event_context *ctx)
3388 raw_spin_lock_init(&ctx->lock);
3389 mutex_init(&ctx->mutex);
3390 INIT_LIST_HEAD(&ctx->active_ctx_list);
3391 INIT_LIST_HEAD(&ctx->pinned_groups);
3392 INIT_LIST_HEAD(&ctx->flexible_groups);
3393 INIT_LIST_HEAD(&ctx->event_list);
3394 atomic_set(&ctx->refcount, 1);
3395 INIT_DELAYED_WORK(&ctx->orphans_remove, orphans_remove_work);
3398 static struct perf_event_context *
3399 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3401 struct perf_event_context *ctx;
3403 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3407 __perf_event_init_context(ctx);
3410 get_task_struct(task);
3417 static struct task_struct *
3418 find_lively_task_by_vpid(pid_t vpid)
3420 struct task_struct *task;
3427 task = find_task_by_vpid(vpid);
3429 get_task_struct(task);
3433 return ERR_PTR(-ESRCH);
3435 /* Reuse ptrace permission checks for now. */
3437 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
3442 put_task_struct(task);
3443 return ERR_PTR(err);
3448 * Returns a matching context with refcount and pincount.
3450 static struct perf_event_context *
3451 find_get_context(struct pmu *pmu, struct task_struct *task,
3452 struct perf_event *event)
3454 struct perf_event_context *ctx, *clone_ctx = NULL;
3455 struct perf_cpu_context *cpuctx;
3456 void *task_ctx_data = NULL;
3457 unsigned long flags;
3459 int cpu = event->cpu;
3462 /* Must be root to operate on a CPU event: */
3463 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3464 return ERR_PTR(-EACCES);
3467 * We could be clever and allow to attach a event to an
3468 * offline CPU and activate it when the CPU comes up, but
3471 if (!cpu_online(cpu))
3472 return ERR_PTR(-ENODEV);
3474 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3483 ctxn = pmu->task_ctx_nr;
3487 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3488 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3489 if (!task_ctx_data) {
3496 ctx = perf_lock_task_context(task, ctxn, &flags);
3498 clone_ctx = unclone_ctx(ctx);
3501 if (task_ctx_data && !ctx->task_ctx_data) {
3502 ctx->task_ctx_data = task_ctx_data;
3503 task_ctx_data = NULL;
3505 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3510 ctx = alloc_perf_context(pmu, task);
3515 if (task_ctx_data) {
3516 ctx->task_ctx_data = task_ctx_data;
3517 task_ctx_data = NULL;
3521 mutex_lock(&task->perf_event_mutex);
3523 * If it has already passed perf_event_exit_task().
3524 * we must see PF_EXITING, it takes this mutex too.
3526 if (task->flags & PF_EXITING)
3528 else if (task->perf_event_ctxp[ctxn])
3533 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3535 mutex_unlock(&task->perf_event_mutex);
3537 if (unlikely(err)) {
3546 kfree(task_ctx_data);
3550 kfree(task_ctx_data);
3551 return ERR_PTR(err);
3554 static void perf_event_free_filter(struct perf_event *event);
3555 static void perf_event_free_bpf_prog(struct perf_event *event);
3557 static void free_event_rcu(struct rcu_head *head)
3559 struct perf_event *event;
3561 event = container_of(head, struct perf_event, rcu_head);
3563 put_pid_ns(event->ns);
3564 perf_event_free_filter(event);
3568 static void ring_buffer_attach(struct perf_event *event,
3569 struct ring_buffer *rb);
3571 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3576 if (is_cgroup_event(event))
3577 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3580 static void unaccount_event(struct perf_event *event)
3585 if (event->attach_state & PERF_ATTACH_TASK)
3586 static_key_slow_dec_deferred(&perf_sched_events);
3587 if (event->attr.mmap || event->attr.mmap_data)
3588 atomic_dec(&nr_mmap_events);
3589 if (event->attr.comm)
3590 atomic_dec(&nr_comm_events);
3591 if (event->attr.task)
3592 atomic_dec(&nr_task_events);
3593 if (event->attr.freq)
3594 atomic_dec(&nr_freq_events);
3595 if (event->attr.context_switch) {
3596 static_key_slow_dec_deferred(&perf_sched_events);
3597 atomic_dec(&nr_switch_events);
3599 if (is_cgroup_event(event))
3600 static_key_slow_dec_deferred(&perf_sched_events);
3601 if (has_branch_stack(event))
3602 static_key_slow_dec_deferred(&perf_sched_events);
3604 unaccount_event_cpu(event, event->cpu);
3608 * The following implement mutual exclusion of events on "exclusive" pmus
3609 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3610 * at a time, so we disallow creating events that might conflict, namely:
3612 * 1) cpu-wide events in the presence of per-task events,
3613 * 2) per-task events in the presence of cpu-wide events,
3614 * 3) two matching events on the same context.
3616 * The former two cases are handled in the allocation path (perf_event_alloc(),
3617 * __free_event()), the latter -- before the first perf_install_in_context().
3619 static int exclusive_event_init(struct perf_event *event)
3621 struct pmu *pmu = event->pmu;
3623 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3627 * Prevent co-existence of per-task and cpu-wide events on the
3628 * same exclusive pmu.
3630 * Negative pmu::exclusive_cnt means there are cpu-wide
3631 * events on this "exclusive" pmu, positive means there are
3634 * Since this is called in perf_event_alloc() path, event::ctx
3635 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3636 * to mean "per-task event", because unlike other attach states it
3637 * never gets cleared.
3639 if (event->attach_state & PERF_ATTACH_TASK) {
3640 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
3643 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
3650 static void exclusive_event_destroy(struct perf_event *event)
3652 struct pmu *pmu = event->pmu;
3654 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3657 /* see comment in exclusive_event_init() */
3658 if (event->attach_state & PERF_ATTACH_TASK)
3659 atomic_dec(&pmu->exclusive_cnt);
3661 atomic_inc(&pmu->exclusive_cnt);
3664 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
3666 if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
3667 (e1->cpu == e2->cpu ||
3674 /* Called under the same ctx::mutex as perf_install_in_context() */
3675 static bool exclusive_event_installable(struct perf_event *event,
3676 struct perf_event_context *ctx)
3678 struct perf_event *iter_event;
3679 struct pmu *pmu = event->pmu;
3681 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3684 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
3685 if (exclusive_event_match(iter_event, event))
3692 static void __free_event(struct perf_event *event)
3694 if (!event->parent) {
3695 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3696 put_callchain_buffers();
3699 perf_event_free_bpf_prog(event);
3702 event->destroy(event);
3705 put_ctx(event->ctx);
3708 exclusive_event_destroy(event);
3709 module_put(event->pmu->module);
3712 call_rcu(&event->rcu_head, free_event_rcu);
3715 static void _free_event(struct perf_event *event)
3717 irq_work_sync(&event->pending);
3719 unaccount_event(event);
3723 * Can happen when we close an event with re-directed output.
3725 * Since we have a 0 refcount, perf_mmap_close() will skip
3726 * over us; possibly making our ring_buffer_put() the last.
3728 mutex_lock(&event->mmap_mutex);
3729 ring_buffer_attach(event, NULL);
3730 mutex_unlock(&event->mmap_mutex);
3733 if (is_cgroup_event(event))
3734 perf_detach_cgroup(event);
3736 __free_event(event);
3740 * Used to free events which have a known refcount of 1, such as in error paths
3741 * where the event isn't exposed yet and inherited events.
3743 static void free_event(struct perf_event *event)
3745 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
3746 "unexpected event refcount: %ld; ptr=%p\n",
3747 atomic_long_read(&event->refcount), event)) {
3748 /* leak to avoid use-after-free */
3756 * Remove user event from the owner task.
3758 static void perf_remove_from_owner(struct perf_event *event)
3760 struct task_struct *owner;
3763 owner = ACCESS_ONCE(event->owner);
3765 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
3766 * !owner it means the list deletion is complete and we can indeed
3767 * free this event, otherwise we need to serialize on
3768 * owner->perf_event_mutex.
3770 smp_read_barrier_depends();
3773 * Since delayed_put_task_struct() also drops the last
3774 * task reference we can safely take a new reference
3775 * while holding the rcu_read_lock().
3777 get_task_struct(owner);
3783 * If we're here through perf_event_exit_task() we're already
3784 * holding ctx->mutex which would be an inversion wrt. the
3785 * normal lock order.
3787 * However we can safely take this lock because its the child
3790 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
3793 * We have to re-check the event->owner field, if it is cleared
3794 * we raced with perf_event_exit_task(), acquiring the mutex
3795 * ensured they're done, and we can proceed with freeing the
3799 list_del_init(&event->owner_entry);
3800 mutex_unlock(&owner->perf_event_mutex);
3801 put_task_struct(owner);
3805 static void put_event(struct perf_event *event)
3807 struct perf_event_context *ctx;
3809 if (!atomic_long_dec_and_test(&event->refcount))
3812 if (!is_kernel_event(event))
3813 perf_remove_from_owner(event);
3816 * There are two ways this annotation is useful:
3818 * 1) there is a lock recursion from perf_event_exit_task
3819 * see the comment there.
3821 * 2) there is a lock-inversion with mmap_sem through
3822 * perf_read_group(), which takes faults while
3823 * holding ctx->mutex, however this is called after
3824 * the last filedesc died, so there is no possibility
3825 * to trigger the AB-BA case.
3827 ctx = perf_event_ctx_lock_nested(event, SINGLE_DEPTH_NESTING);
3828 WARN_ON_ONCE(ctx->parent_ctx);
3829 perf_remove_from_context(event, true);
3830 perf_event_ctx_unlock(event, ctx);
3835 int perf_event_release_kernel(struct perf_event *event)
3840 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
3843 * Called when the last reference to the file is gone.
3845 static int perf_release(struct inode *inode, struct file *file)
3847 put_event(file->private_data);
3852 * Remove all orphanes events from the context.
3854 static void orphans_remove_work(struct work_struct *work)
3856 struct perf_event_context *ctx;
3857 struct perf_event *event, *tmp;
3859 ctx = container_of(work, struct perf_event_context,
3860 orphans_remove.work);
3862 mutex_lock(&ctx->mutex);
3863 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry) {
3864 struct perf_event *parent_event = event->parent;
3866 if (!is_orphaned_child(event))
3869 perf_remove_from_context(event, true);
3871 mutex_lock(&parent_event->child_mutex);
3872 list_del_init(&event->child_list);
3873 mutex_unlock(&parent_event->child_mutex);
3876 put_event(parent_event);
3879 raw_spin_lock_irq(&ctx->lock);
3880 ctx->orphans_remove_sched = false;
3881 raw_spin_unlock_irq(&ctx->lock);
3882 mutex_unlock(&ctx->mutex);
3887 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3889 struct perf_event *child;
3895 mutex_lock(&event->child_mutex);
3897 (void)perf_event_read(event, false);
3898 total += perf_event_count(event);
3900 *enabled += event->total_time_enabled +
3901 atomic64_read(&event->child_total_time_enabled);
3902 *running += event->total_time_running +
3903 atomic64_read(&event->child_total_time_running);
3905 list_for_each_entry(child, &event->child_list, child_list) {
3906 (void)perf_event_read(child, false);
3907 total += perf_event_count(child);
3908 *enabled += child->total_time_enabled;
3909 *running += child->total_time_running;
3911 mutex_unlock(&event->child_mutex);
3915 EXPORT_SYMBOL_GPL(perf_event_read_value);
3917 static int __perf_read_group_add(struct perf_event *leader,
3918 u64 read_format, u64 *values)
3920 struct perf_event *sub;
3921 int n = 1; /* skip @nr */
3924 ret = perf_event_read(leader, true);
3929 * Since we co-schedule groups, {enabled,running} times of siblings
3930 * will be identical to those of the leader, so we only publish one
3933 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3934 values[n++] += leader->total_time_enabled +
3935 atomic64_read(&leader->child_total_time_enabled);
3938 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3939 values[n++] += leader->total_time_running +
3940 atomic64_read(&leader->child_total_time_running);
3944 * Write {count,id} tuples for every sibling.
3946 values[n++] += perf_event_count(leader);
3947 if (read_format & PERF_FORMAT_ID)
3948 values[n++] = primary_event_id(leader);
3950 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3951 values[n++] += perf_event_count(sub);
3952 if (read_format & PERF_FORMAT_ID)
3953 values[n++] = primary_event_id(sub);
3959 static int perf_read_group(struct perf_event *event,
3960 u64 read_format, char __user *buf)
3962 struct perf_event *leader = event->group_leader, *child;
3963 struct perf_event_context *ctx = leader->ctx;
3967 lockdep_assert_held(&ctx->mutex);
3969 values = kzalloc(event->read_size, GFP_KERNEL);
3973 values[0] = 1 + leader->nr_siblings;
3976 * By locking the child_mutex of the leader we effectively
3977 * lock the child list of all siblings.. XXX explain how.
3979 mutex_lock(&leader->child_mutex);
3981 ret = __perf_read_group_add(leader, read_format, values);
3985 list_for_each_entry(child, &leader->child_list, child_list) {
3986 ret = __perf_read_group_add(child, read_format, values);
3991 mutex_unlock(&leader->child_mutex);
3993 ret = event->read_size;
3994 if (copy_to_user(buf, values, event->read_size))
3999 mutex_unlock(&leader->child_mutex);
4005 static int perf_read_one(struct perf_event *event,
4006 u64 read_format, char __user *buf)
4008 u64 enabled, running;
4012 values[n++] = perf_event_read_value(event, &enabled, &running);
4013 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4014 values[n++] = enabled;
4015 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4016 values[n++] = running;
4017 if (read_format & PERF_FORMAT_ID)
4018 values[n++] = primary_event_id(event);
4020 if (copy_to_user(buf, values, n * sizeof(u64)))
4023 return n * sizeof(u64);
4026 static bool is_event_hup(struct perf_event *event)
4030 if (event->state != PERF_EVENT_STATE_EXIT)
4033 mutex_lock(&event->child_mutex);
4034 no_children = list_empty(&event->child_list);
4035 mutex_unlock(&event->child_mutex);
4040 * Read the performance event - simple non blocking version for now
4043 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4045 u64 read_format = event->attr.read_format;
4049 * Return end-of-file for a read on a event that is in
4050 * error state (i.e. because it was pinned but it couldn't be
4051 * scheduled on to the CPU at some point).
4053 if (event->state == PERF_EVENT_STATE_ERROR)
4056 if (count < event->read_size)
4059 WARN_ON_ONCE(event->ctx->parent_ctx);
4060 if (read_format & PERF_FORMAT_GROUP)
4061 ret = perf_read_group(event, read_format, buf);
4063 ret = perf_read_one(event, read_format, buf);
4069 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4071 struct perf_event *event = file->private_data;
4072 struct perf_event_context *ctx;
4075 ctx = perf_event_ctx_lock(event);
4076 ret = __perf_read(event, buf, count);
4077 perf_event_ctx_unlock(event, ctx);
4082 static unsigned int perf_poll(struct file *file, poll_table *wait)
4084 struct perf_event *event = file->private_data;
4085 struct ring_buffer *rb;
4086 unsigned int events = POLLHUP;
4088 poll_wait(file, &event->waitq, wait);
4090 if (is_event_hup(event))
4094 * Pin the event->rb by taking event->mmap_mutex; otherwise
4095 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4097 mutex_lock(&event->mmap_mutex);
4100 events = atomic_xchg(&rb->poll, 0);
4101 mutex_unlock(&event->mmap_mutex);
4105 static void _perf_event_reset(struct perf_event *event)
4107 (void)perf_event_read(event, false);
4108 local64_set(&event->count, 0);
4109 perf_event_update_userpage(event);
4113 * Holding the top-level event's child_mutex means that any
4114 * descendant process that has inherited this event will block
4115 * in sync_child_event if it goes to exit, thus satisfying the
4116 * task existence requirements of perf_event_enable/disable.
4118 static void perf_event_for_each_child(struct perf_event *event,
4119 void (*func)(struct perf_event *))
4121 struct perf_event *child;
4123 WARN_ON_ONCE(event->ctx->parent_ctx);
4125 mutex_lock(&event->child_mutex);
4127 list_for_each_entry(child, &event->child_list, child_list)
4129 mutex_unlock(&event->child_mutex);
4132 static void perf_event_for_each(struct perf_event *event,
4133 void (*func)(struct perf_event *))
4135 struct perf_event_context *ctx = event->ctx;
4136 struct perf_event *sibling;
4138 lockdep_assert_held(&ctx->mutex);
4140 event = event->group_leader;
4142 perf_event_for_each_child(event, func);
4143 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4144 perf_event_for_each_child(sibling, func);
4147 struct period_event {
4148 struct perf_event *event;
4152 static int __perf_event_period(void *info)
4154 struct period_event *pe = info;
4155 struct perf_event *event = pe->event;
4156 struct perf_event_context *ctx = event->ctx;
4157 u64 value = pe->value;
4160 raw_spin_lock(&ctx->lock);
4161 if (event->attr.freq) {
4162 event->attr.sample_freq = value;
4164 event->attr.sample_period = value;
4165 event->hw.sample_period = value;
4168 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4170 perf_pmu_disable(ctx->pmu);
4171 event->pmu->stop(event, PERF_EF_UPDATE);
4174 local64_set(&event->hw.period_left, 0);
4177 event->pmu->start(event, PERF_EF_RELOAD);
4178 perf_pmu_enable(ctx->pmu);
4180 raw_spin_unlock(&ctx->lock);
4185 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4187 struct period_event pe = { .event = event, };
4188 struct perf_event_context *ctx = event->ctx;
4189 struct task_struct *task;
4192 if (!is_sampling_event(event))
4195 if (copy_from_user(&value, arg, sizeof(value)))
4201 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4208 cpu_function_call(event->cpu, __perf_event_period, &pe);
4213 if (!task_function_call(task, __perf_event_period, &pe))
4216 raw_spin_lock_irq(&ctx->lock);
4217 if (ctx->is_active) {
4218 raw_spin_unlock_irq(&ctx->lock);
4223 if (event->attr.freq) {
4224 event->attr.sample_freq = value;
4226 event->attr.sample_period = value;
4227 event->hw.sample_period = value;
4230 local64_set(&event->hw.period_left, 0);
4231 raw_spin_unlock_irq(&ctx->lock);
4236 static const struct file_operations perf_fops;
4238 static inline int perf_fget_light(int fd, struct fd *p)
4240 struct fd f = fdget(fd);
4244 if (f.file->f_op != &perf_fops) {
4252 static int perf_event_set_output(struct perf_event *event,
4253 struct perf_event *output_event);
4254 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4255 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4257 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4259 void (*func)(struct perf_event *);
4263 case PERF_EVENT_IOC_ENABLE:
4264 func = _perf_event_enable;
4266 case PERF_EVENT_IOC_DISABLE:
4267 func = _perf_event_disable;
4269 case PERF_EVENT_IOC_RESET:
4270 func = _perf_event_reset;
4273 case PERF_EVENT_IOC_REFRESH:
4274 return _perf_event_refresh(event, arg);
4276 case PERF_EVENT_IOC_PERIOD:
4277 return perf_event_period(event, (u64 __user *)arg);
4279 case PERF_EVENT_IOC_ID:
4281 u64 id = primary_event_id(event);
4283 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4288 case PERF_EVENT_IOC_SET_OUTPUT:
4292 struct perf_event *output_event;
4294 ret = perf_fget_light(arg, &output);
4297 output_event = output.file->private_data;
4298 ret = perf_event_set_output(event, output_event);
4301 ret = perf_event_set_output(event, NULL);
4306 case PERF_EVENT_IOC_SET_FILTER:
4307 return perf_event_set_filter(event, (void __user *)arg);
4309 case PERF_EVENT_IOC_SET_BPF:
4310 return perf_event_set_bpf_prog(event, arg);
4316 if (flags & PERF_IOC_FLAG_GROUP)
4317 perf_event_for_each(event, func);
4319 perf_event_for_each_child(event, func);
4324 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4326 struct perf_event *event = file->private_data;
4327 struct perf_event_context *ctx;
4330 ctx = perf_event_ctx_lock(event);
4331 ret = _perf_ioctl(event, cmd, arg);
4332 perf_event_ctx_unlock(event, ctx);
4337 #ifdef CONFIG_COMPAT
4338 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4341 switch (_IOC_NR(cmd)) {
4342 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4343 case _IOC_NR(PERF_EVENT_IOC_ID):
4344 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4345 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4346 cmd &= ~IOCSIZE_MASK;
4347 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4351 return perf_ioctl(file, cmd, arg);
4354 # define perf_compat_ioctl NULL
4357 int perf_event_task_enable(void)
4359 struct perf_event_context *ctx;
4360 struct perf_event *event;
4362 mutex_lock(¤t->perf_event_mutex);
4363 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4364 ctx = perf_event_ctx_lock(event);
4365 perf_event_for_each_child(event, _perf_event_enable);
4366 perf_event_ctx_unlock(event, ctx);
4368 mutex_unlock(¤t->perf_event_mutex);
4373 int perf_event_task_disable(void)
4375 struct perf_event_context *ctx;
4376 struct perf_event *event;
4378 mutex_lock(¤t->perf_event_mutex);
4379 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4380 ctx = perf_event_ctx_lock(event);
4381 perf_event_for_each_child(event, _perf_event_disable);
4382 perf_event_ctx_unlock(event, ctx);
4384 mutex_unlock(¤t->perf_event_mutex);
4389 static int perf_event_index(struct perf_event *event)
4391 if (event->hw.state & PERF_HES_STOPPED)
4394 if (event->state != PERF_EVENT_STATE_ACTIVE)
4397 return event->pmu->event_idx(event);
4400 static void calc_timer_values(struct perf_event *event,
4407 *now = perf_clock();
4408 ctx_time = event->shadow_ctx_time + *now;
4409 *enabled = ctx_time - event->tstamp_enabled;
4410 *running = ctx_time - event->tstamp_running;
4413 static void perf_event_init_userpage(struct perf_event *event)
4415 struct perf_event_mmap_page *userpg;
4416 struct ring_buffer *rb;
4419 rb = rcu_dereference(event->rb);
4423 userpg = rb->user_page;
4425 /* Allow new userspace to detect that bit 0 is deprecated */
4426 userpg->cap_bit0_is_deprecated = 1;
4427 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4428 userpg->data_offset = PAGE_SIZE;
4429 userpg->data_size = perf_data_size(rb);
4435 void __weak arch_perf_update_userpage(
4436 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4441 * Callers need to ensure there can be no nesting of this function, otherwise
4442 * the seqlock logic goes bad. We can not serialize this because the arch
4443 * code calls this from NMI context.
4445 void perf_event_update_userpage(struct perf_event *event)
4447 struct perf_event_mmap_page *userpg;
4448 struct ring_buffer *rb;
4449 u64 enabled, running, now;
4452 rb = rcu_dereference(event->rb);
4457 * compute total_time_enabled, total_time_running
4458 * based on snapshot values taken when the event
4459 * was last scheduled in.
4461 * we cannot simply called update_context_time()
4462 * because of locking issue as we can be called in
4465 calc_timer_values(event, &now, &enabled, &running);
4467 userpg = rb->user_page;
4469 * Disable preemption so as to not let the corresponding user-space
4470 * spin too long if we get preempted.
4475 userpg->index = perf_event_index(event);
4476 userpg->offset = perf_event_count(event);
4478 userpg->offset -= local64_read(&event->hw.prev_count);
4480 userpg->time_enabled = enabled +
4481 atomic64_read(&event->child_total_time_enabled);
4483 userpg->time_running = running +
4484 atomic64_read(&event->child_total_time_running);
4486 arch_perf_update_userpage(event, userpg, now);
4495 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4497 struct perf_event *event = vma->vm_file->private_data;
4498 struct ring_buffer *rb;
4499 int ret = VM_FAULT_SIGBUS;
4501 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4502 if (vmf->pgoff == 0)
4508 rb = rcu_dereference(event->rb);
4512 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4515 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4519 get_page(vmf->page);
4520 vmf->page->mapping = vma->vm_file->f_mapping;
4521 vmf->page->index = vmf->pgoff;
4530 static void ring_buffer_attach(struct perf_event *event,
4531 struct ring_buffer *rb)
4533 struct ring_buffer *old_rb = NULL;
4534 unsigned long flags;
4538 * Should be impossible, we set this when removing
4539 * event->rb_entry and wait/clear when adding event->rb_entry.
4541 WARN_ON_ONCE(event->rcu_pending);
4544 spin_lock_irqsave(&old_rb->event_lock, flags);
4545 list_del_rcu(&event->rb_entry);
4546 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4548 event->rcu_batches = get_state_synchronize_rcu();
4549 event->rcu_pending = 1;
4553 if (event->rcu_pending) {
4554 cond_synchronize_rcu(event->rcu_batches);
4555 event->rcu_pending = 0;
4558 spin_lock_irqsave(&rb->event_lock, flags);
4559 list_add_rcu(&event->rb_entry, &rb->event_list);
4560 spin_unlock_irqrestore(&rb->event_lock, flags);
4563 rcu_assign_pointer(event->rb, rb);
4566 ring_buffer_put(old_rb);
4568 * Since we detached before setting the new rb, so that we
4569 * could attach the new rb, we could have missed a wakeup.
4572 wake_up_all(&event->waitq);
4576 static void ring_buffer_wakeup(struct perf_event *event)
4578 struct ring_buffer *rb;
4581 rb = rcu_dereference(event->rb);
4583 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4584 wake_up_all(&event->waitq);
4589 struct ring_buffer *ring_buffer_get(struct perf_event *event)
4591 struct ring_buffer *rb;
4594 rb = rcu_dereference(event->rb);
4596 if (!atomic_inc_not_zero(&rb->refcount))
4604 void ring_buffer_put(struct ring_buffer *rb)
4606 if (!atomic_dec_and_test(&rb->refcount))
4609 WARN_ON_ONCE(!list_empty(&rb->event_list));
4611 call_rcu(&rb->rcu_head, rb_free_rcu);
4614 static void perf_mmap_open(struct vm_area_struct *vma)
4616 struct perf_event *event = vma->vm_file->private_data;
4618 atomic_inc(&event->mmap_count);
4619 atomic_inc(&event->rb->mmap_count);
4622 atomic_inc(&event->rb->aux_mmap_count);
4624 if (event->pmu->event_mapped)
4625 event->pmu->event_mapped(event);
4629 * A buffer can be mmap()ed multiple times; either directly through the same
4630 * event, or through other events by use of perf_event_set_output().
4632 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4633 * the buffer here, where we still have a VM context. This means we need
4634 * to detach all events redirecting to us.
4636 static void perf_mmap_close(struct vm_area_struct *vma)
4638 struct perf_event *event = vma->vm_file->private_data;
4640 struct ring_buffer *rb = ring_buffer_get(event);
4641 struct user_struct *mmap_user = rb->mmap_user;
4642 int mmap_locked = rb->mmap_locked;
4643 unsigned long size = perf_data_size(rb);
4645 if (event->pmu->event_unmapped)
4646 event->pmu->event_unmapped(event);
4649 * rb->aux_mmap_count will always drop before rb->mmap_count and
4650 * event->mmap_count, so it is ok to use event->mmap_mutex to
4651 * serialize with perf_mmap here.
4653 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
4654 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
4655 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
4656 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
4659 mutex_unlock(&event->mmap_mutex);
4662 atomic_dec(&rb->mmap_count);
4664 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4667 ring_buffer_attach(event, NULL);
4668 mutex_unlock(&event->mmap_mutex);
4670 /* If there's still other mmap()s of this buffer, we're done. */
4671 if (atomic_read(&rb->mmap_count))
4675 * No other mmap()s, detach from all other events that might redirect
4676 * into the now unreachable buffer. Somewhat complicated by the
4677 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4681 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
4682 if (!atomic_long_inc_not_zero(&event->refcount)) {
4684 * This event is en-route to free_event() which will
4685 * detach it and remove it from the list.
4691 mutex_lock(&event->mmap_mutex);
4693 * Check we didn't race with perf_event_set_output() which can
4694 * swizzle the rb from under us while we were waiting to
4695 * acquire mmap_mutex.
4697 * If we find a different rb; ignore this event, a next
4698 * iteration will no longer find it on the list. We have to
4699 * still restart the iteration to make sure we're not now
4700 * iterating the wrong list.
4702 if (event->rb == rb)
4703 ring_buffer_attach(event, NULL);
4705 mutex_unlock(&event->mmap_mutex);
4709 * Restart the iteration; either we're on the wrong list or
4710 * destroyed its integrity by doing a deletion.
4717 * It could be there's still a few 0-ref events on the list; they'll
4718 * get cleaned up by free_event() -- they'll also still have their
4719 * ref on the rb and will free it whenever they are done with it.
4721 * Aside from that, this buffer is 'fully' detached and unmapped,
4722 * undo the VM accounting.
4725 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
4726 vma->vm_mm->pinned_vm -= mmap_locked;
4727 free_uid(mmap_user);
4730 ring_buffer_put(rb); /* could be last */
4733 static const struct vm_operations_struct perf_mmap_vmops = {
4734 .open = perf_mmap_open,
4735 .close = perf_mmap_close, /* non mergable */
4736 .fault = perf_mmap_fault,
4737 .page_mkwrite = perf_mmap_fault,
4740 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
4742 struct perf_event *event = file->private_data;
4743 unsigned long user_locked, user_lock_limit;
4744 struct user_struct *user = current_user();
4745 unsigned long locked, lock_limit;
4746 struct ring_buffer *rb = NULL;
4747 unsigned long vma_size;
4748 unsigned long nr_pages;
4749 long user_extra = 0, extra = 0;
4750 int ret = 0, flags = 0;
4753 * Don't allow mmap() of inherited per-task counters. This would
4754 * create a performance issue due to all children writing to the
4757 if (event->cpu == -1 && event->attr.inherit)
4760 if (!(vma->vm_flags & VM_SHARED))
4763 vma_size = vma->vm_end - vma->vm_start;
4765 if (vma->vm_pgoff == 0) {
4766 nr_pages = (vma_size / PAGE_SIZE) - 1;
4769 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
4770 * mapped, all subsequent mappings should have the same size
4771 * and offset. Must be above the normal perf buffer.
4773 u64 aux_offset, aux_size;
4778 nr_pages = vma_size / PAGE_SIZE;
4780 mutex_lock(&event->mmap_mutex);
4787 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
4788 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
4790 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
4793 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
4796 /* already mapped with a different offset */
4797 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
4800 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
4803 /* already mapped with a different size */
4804 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
4807 if (!is_power_of_2(nr_pages))
4810 if (!atomic_inc_not_zero(&rb->mmap_count))
4813 if (rb_has_aux(rb)) {
4814 atomic_inc(&rb->aux_mmap_count);
4819 atomic_set(&rb->aux_mmap_count, 1);
4820 user_extra = nr_pages;
4826 * If we have rb pages ensure they're a power-of-two number, so we
4827 * can do bitmasks instead of modulo.
4829 if (nr_pages != 0 && !is_power_of_2(nr_pages))
4832 if (vma_size != PAGE_SIZE * (1 + nr_pages))
4835 WARN_ON_ONCE(event->ctx->parent_ctx);
4837 mutex_lock(&event->mmap_mutex);
4839 if (event->rb->nr_pages != nr_pages) {
4844 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
4846 * Raced against perf_mmap_close() through
4847 * perf_event_set_output(). Try again, hope for better
4850 mutex_unlock(&event->mmap_mutex);
4857 user_extra = nr_pages + 1;
4860 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
4863 * Increase the limit linearly with more CPUs:
4865 user_lock_limit *= num_online_cpus();
4867 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
4869 if (user_locked > user_lock_limit)
4870 extra = user_locked - user_lock_limit;
4872 lock_limit = rlimit(RLIMIT_MEMLOCK);
4873 lock_limit >>= PAGE_SHIFT;
4874 locked = vma->vm_mm->pinned_vm + extra;
4876 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
4877 !capable(CAP_IPC_LOCK)) {
4882 WARN_ON(!rb && event->rb);
4884 if (vma->vm_flags & VM_WRITE)
4885 flags |= RING_BUFFER_WRITABLE;
4888 rb = rb_alloc(nr_pages,
4889 event->attr.watermark ? event->attr.wakeup_watermark : 0,
4897 atomic_set(&rb->mmap_count, 1);
4898 rb->mmap_user = get_current_user();
4899 rb->mmap_locked = extra;
4901 ring_buffer_attach(event, rb);
4903 perf_event_init_userpage(event);
4904 perf_event_update_userpage(event);
4906 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
4907 event->attr.aux_watermark, flags);
4909 rb->aux_mmap_locked = extra;
4914 atomic_long_add(user_extra, &user->locked_vm);
4915 vma->vm_mm->pinned_vm += extra;
4917 atomic_inc(&event->mmap_count);
4919 atomic_dec(&rb->mmap_count);
4922 mutex_unlock(&event->mmap_mutex);
4925 * Since pinned accounting is per vm we cannot allow fork() to copy our
4928 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
4929 vma->vm_ops = &perf_mmap_vmops;
4931 if (event->pmu->event_mapped)
4932 event->pmu->event_mapped(event);
4937 static int perf_fasync(int fd, struct file *filp, int on)
4939 struct inode *inode = file_inode(filp);
4940 struct perf_event *event = filp->private_data;
4943 mutex_lock(&inode->i_mutex);
4944 retval = fasync_helper(fd, filp, on, &event->fasync);
4945 mutex_unlock(&inode->i_mutex);
4953 static const struct file_operations perf_fops = {
4954 .llseek = no_llseek,
4955 .release = perf_release,
4958 .unlocked_ioctl = perf_ioctl,
4959 .compat_ioctl = perf_compat_ioctl,
4961 .fasync = perf_fasync,
4967 * If there's data, ensure we set the poll() state and publish everything
4968 * to user-space before waking everybody up.
4971 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
4973 /* only the parent has fasync state */
4975 event = event->parent;
4976 return &event->fasync;
4979 void perf_event_wakeup(struct perf_event *event)
4981 ring_buffer_wakeup(event);
4983 if (event->pending_kill) {
4984 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
4985 event->pending_kill = 0;
4989 static void perf_pending_event(struct irq_work *entry)
4991 struct perf_event *event = container_of(entry,
4992 struct perf_event, pending);
4995 rctx = perf_swevent_get_recursion_context();
4997 * If we 'fail' here, that's OK, it means recursion is already disabled
4998 * and we won't recurse 'further'.
5001 if (event->pending_disable) {
5002 event->pending_disable = 0;
5003 __perf_event_disable(event);
5006 if (event->pending_wakeup) {
5007 event->pending_wakeup = 0;
5008 perf_event_wakeup(event);
5012 perf_swevent_put_recursion_context(rctx);
5016 * We assume there is only KVM supporting the callbacks.
5017 * Later on, we might change it to a list if there is
5018 * another virtualization implementation supporting the callbacks.
5020 struct perf_guest_info_callbacks *perf_guest_cbs;
5022 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5024 perf_guest_cbs = cbs;
5027 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5029 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5031 perf_guest_cbs = NULL;
5034 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5037 perf_output_sample_regs(struct perf_output_handle *handle,
5038 struct pt_regs *regs, u64 mask)
5042 for_each_set_bit(bit, (const unsigned long *) &mask,
5043 sizeof(mask) * BITS_PER_BYTE) {
5046 val = perf_reg_value(regs, bit);
5047 perf_output_put(handle, val);
5051 static void perf_sample_regs_user(struct perf_regs *regs_user,
5052 struct pt_regs *regs,
5053 struct pt_regs *regs_user_copy)
5055 if (user_mode(regs)) {
5056 regs_user->abi = perf_reg_abi(current);
5057 regs_user->regs = regs;
5058 } else if (current->mm) {
5059 perf_get_regs_user(regs_user, regs, regs_user_copy);
5061 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5062 regs_user->regs = NULL;
5066 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5067 struct pt_regs *regs)
5069 regs_intr->regs = regs;
5070 regs_intr->abi = perf_reg_abi(current);
5075 * Get remaining task size from user stack pointer.
5077 * It'd be better to take stack vma map and limit this more
5078 * precisly, but there's no way to get it safely under interrupt,
5079 * so using TASK_SIZE as limit.
5081 static u64 perf_ustack_task_size(struct pt_regs *regs)
5083 unsigned long addr = perf_user_stack_pointer(regs);
5085 if (!addr || addr >= TASK_SIZE)
5088 return TASK_SIZE - addr;
5092 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5093 struct pt_regs *regs)
5097 /* No regs, no stack pointer, no dump. */
5102 * Check if we fit in with the requested stack size into the:
5104 * If we don't, we limit the size to the TASK_SIZE.
5106 * - remaining sample size
5107 * If we don't, we customize the stack size to
5108 * fit in to the remaining sample size.
5111 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5112 stack_size = min(stack_size, (u16) task_size);
5114 /* Current header size plus static size and dynamic size. */
5115 header_size += 2 * sizeof(u64);
5117 /* Do we fit in with the current stack dump size? */
5118 if ((u16) (header_size + stack_size) < header_size) {
5120 * If we overflow the maximum size for the sample,
5121 * we customize the stack dump size to fit in.
5123 stack_size = USHRT_MAX - header_size - sizeof(u64);
5124 stack_size = round_up(stack_size, sizeof(u64));
5131 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5132 struct pt_regs *regs)
5134 /* Case of a kernel thread, nothing to dump */
5137 perf_output_put(handle, size);
5146 * - the size requested by user or the best one we can fit
5147 * in to the sample max size
5149 * - user stack dump data
5151 * - the actual dumped size
5155 perf_output_put(handle, dump_size);
5158 sp = perf_user_stack_pointer(regs);
5159 rem = __output_copy_user(handle, (void *) sp, dump_size);
5160 dyn_size = dump_size - rem;
5162 perf_output_skip(handle, rem);
5165 perf_output_put(handle, dyn_size);
5169 static void __perf_event_header__init_id(struct perf_event_header *header,
5170 struct perf_sample_data *data,
5171 struct perf_event *event)
5173 u64 sample_type = event->attr.sample_type;
5175 data->type = sample_type;
5176 header->size += event->id_header_size;
5178 if (sample_type & PERF_SAMPLE_TID) {
5179 /* namespace issues */
5180 data->tid_entry.pid = perf_event_pid(event, current);
5181 data->tid_entry.tid = perf_event_tid(event, current);
5184 if (sample_type & PERF_SAMPLE_TIME)
5185 data->time = perf_event_clock(event);
5187 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5188 data->id = primary_event_id(event);
5190 if (sample_type & PERF_SAMPLE_STREAM_ID)
5191 data->stream_id = event->id;
5193 if (sample_type & PERF_SAMPLE_CPU) {
5194 data->cpu_entry.cpu = raw_smp_processor_id();
5195 data->cpu_entry.reserved = 0;
5199 void perf_event_header__init_id(struct perf_event_header *header,
5200 struct perf_sample_data *data,
5201 struct perf_event *event)
5203 if (event->attr.sample_id_all)
5204 __perf_event_header__init_id(header, data, event);
5207 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5208 struct perf_sample_data *data)
5210 u64 sample_type = data->type;
5212 if (sample_type & PERF_SAMPLE_TID)
5213 perf_output_put(handle, data->tid_entry);
5215 if (sample_type & PERF_SAMPLE_TIME)
5216 perf_output_put(handle, data->time);
5218 if (sample_type & PERF_SAMPLE_ID)
5219 perf_output_put(handle, data->id);
5221 if (sample_type & PERF_SAMPLE_STREAM_ID)
5222 perf_output_put(handle, data->stream_id);
5224 if (sample_type & PERF_SAMPLE_CPU)
5225 perf_output_put(handle, data->cpu_entry);
5227 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5228 perf_output_put(handle, data->id);
5231 void perf_event__output_id_sample(struct perf_event *event,
5232 struct perf_output_handle *handle,
5233 struct perf_sample_data *sample)
5235 if (event->attr.sample_id_all)
5236 __perf_event__output_id_sample(handle, sample);
5239 static void perf_output_read_one(struct perf_output_handle *handle,
5240 struct perf_event *event,
5241 u64 enabled, u64 running)
5243 u64 read_format = event->attr.read_format;
5247 values[n++] = perf_event_count(event);
5248 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5249 values[n++] = enabled +
5250 atomic64_read(&event->child_total_time_enabled);
5252 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5253 values[n++] = running +
5254 atomic64_read(&event->child_total_time_running);
5256 if (read_format & PERF_FORMAT_ID)
5257 values[n++] = primary_event_id(event);
5259 __output_copy(handle, values, n * sizeof(u64));
5263 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5265 static void perf_output_read_group(struct perf_output_handle *handle,
5266 struct perf_event *event,
5267 u64 enabled, u64 running)
5269 struct perf_event *leader = event->group_leader, *sub;
5270 u64 read_format = event->attr.read_format;
5274 values[n++] = 1 + leader->nr_siblings;
5276 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5277 values[n++] = enabled;
5279 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5280 values[n++] = running;
5282 if (leader != event)
5283 leader->pmu->read(leader);
5285 values[n++] = perf_event_count(leader);
5286 if (read_format & PERF_FORMAT_ID)
5287 values[n++] = primary_event_id(leader);
5289 __output_copy(handle, values, n * sizeof(u64));
5291 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5294 if ((sub != event) &&
5295 (sub->state == PERF_EVENT_STATE_ACTIVE))
5296 sub->pmu->read(sub);
5298 values[n++] = perf_event_count(sub);
5299 if (read_format & PERF_FORMAT_ID)
5300 values[n++] = primary_event_id(sub);
5302 __output_copy(handle, values, n * sizeof(u64));
5306 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5307 PERF_FORMAT_TOTAL_TIME_RUNNING)
5309 static void perf_output_read(struct perf_output_handle *handle,
5310 struct perf_event *event)
5312 u64 enabled = 0, running = 0, now;
5313 u64 read_format = event->attr.read_format;
5316 * compute total_time_enabled, total_time_running
5317 * based on snapshot values taken when the event
5318 * was last scheduled in.
5320 * we cannot simply called update_context_time()
5321 * because of locking issue as we are called in
5324 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5325 calc_timer_values(event, &now, &enabled, &running);
5327 if (event->attr.read_format & PERF_FORMAT_GROUP)
5328 perf_output_read_group(handle, event, enabled, running);
5330 perf_output_read_one(handle, event, enabled, running);
5333 void perf_output_sample(struct perf_output_handle *handle,
5334 struct perf_event_header *header,
5335 struct perf_sample_data *data,
5336 struct perf_event *event)
5338 u64 sample_type = data->type;
5340 perf_output_put(handle, *header);
5342 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5343 perf_output_put(handle, data->id);
5345 if (sample_type & PERF_SAMPLE_IP)
5346 perf_output_put(handle, data->ip);
5348 if (sample_type & PERF_SAMPLE_TID)
5349 perf_output_put(handle, data->tid_entry);
5351 if (sample_type & PERF_SAMPLE_TIME)
5352 perf_output_put(handle, data->time);
5354 if (sample_type & PERF_SAMPLE_ADDR)
5355 perf_output_put(handle, data->addr);
5357 if (sample_type & PERF_SAMPLE_ID)
5358 perf_output_put(handle, data->id);
5360 if (sample_type & PERF_SAMPLE_STREAM_ID)
5361 perf_output_put(handle, data->stream_id);
5363 if (sample_type & PERF_SAMPLE_CPU)
5364 perf_output_put(handle, data->cpu_entry);
5366 if (sample_type & PERF_SAMPLE_PERIOD)
5367 perf_output_put(handle, data->period);
5369 if (sample_type & PERF_SAMPLE_READ)
5370 perf_output_read(handle, event);
5372 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5373 if (data->callchain) {
5376 if (data->callchain)
5377 size += data->callchain->nr;
5379 size *= sizeof(u64);
5381 __output_copy(handle, data->callchain, size);
5384 perf_output_put(handle, nr);
5388 if (sample_type & PERF_SAMPLE_RAW) {
5390 u32 raw_size = data->raw->size;
5391 u32 real_size = round_up(raw_size + sizeof(u32),
5392 sizeof(u64)) - sizeof(u32);
5395 perf_output_put(handle, real_size);
5396 __output_copy(handle, data->raw->data, raw_size);
5397 if (real_size - raw_size)
5398 __output_copy(handle, &zero, real_size - raw_size);
5404 .size = sizeof(u32),
5407 perf_output_put(handle, raw);
5411 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5412 if (data->br_stack) {
5415 size = data->br_stack->nr
5416 * sizeof(struct perf_branch_entry);
5418 perf_output_put(handle, data->br_stack->nr);
5419 perf_output_copy(handle, data->br_stack->entries, size);
5422 * we always store at least the value of nr
5425 perf_output_put(handle, nr);
5429 if (sample_type & PERF_SAMPLE_REGS_USER) {
5430 u64 abi = data->regs_user.abi;
5433 * If there are no regs to dump, notice it through
5434 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5436 perf_output_put(handle, abi);
5439 u64 mask = event->attr.sample_regs_user;
5440 perf_output_sample_regs(handle,
5441 data->regs_user.regs,
5446 if (sample_type & PERF_SAMPLE_STACK_USER) {
5447 perf_output_sample_ustack(handle,
5448 data->stack_user_size,
5449 data->regs_user.regs);
5452 if (sample_type & PERF_SAMPLE_WEIGHT)
5453 perf_output_put(handle, data->weight);
5455 if (sample_type & PERF_SAMPLE_DATA_SRC)
5456 perf_output_put(handle, data->data_src.val);
5458 if (sample_type & PERF_SAMPLE_TRANSACTION)
5459 perf_output_put(handle, data->txn);
5461 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5462 u64 abi = data->regs_intr.abi;
5464 * If there are no regs to dump, notice it through
5465 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5467 perf_output_put(handle, abi);
5470 u64 mask = event->attr.sample_regs_intr;
5472 perf_output_sample_regs(handle,
5473 data->regs_intr.regs,
5478 if (!event->attr.watermark) {
5479 int wakeup_events = event->attr.wakeup_events;
5481 if (wakeup_events) {
5482 struct ring_buffer *rb = handle->rb;
5483 int events = local_inc_return(&rb->events);
5485 if (events >= wakeup_events) {
5486 local_sub(wakeup_events, &rb->events);
5487 local_inc(&rb->wakeup);
5493 void perf_prepare_sample(struct perf_event_header *header,
5494 struct perf_sample_data *data,
5495 struct perf_event *event,
5496 struct pt_regs *regs)
5498 u64 sample_type = event->attr.sample_type;
5500 header->type = PERF_RECORD_SAMPLE;
5501 header->size = sizeof(*header) + event->header_size;
5504 header->misc |= perf_misc_flags(regs);
5506 __perf_event_header__init_id(header, data, event);
5508 if (sample_type & PERF_SAMPLE_IP)
5509 data->ip = perf_instruction_pointer(regs);
5511 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5514 data->callchain = perf_callchain(event, regs);
5516 if (data->callchain)
5517 size += data->callchain->nr;
5519 header->size += size * sizeof(u64);
5522 if (sample_type & PERF_SAMPLE_RAW) {
5523 int size = sizeof(u32);
5526 size += data->raw->size;
5528 size += sizeof(u32);
5530 header->size += round_up(size, sizeof(u64));
5533 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5534 int size = sizeof(u64); /* nr */
5535 if (data->br_stack) {
5536 size += data->br_stack->nr
5537 * sizeof(struct perf_branch_entry);
5539 header->size += size;
5542 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5543 perf_sample_regs_user(&data->regs_user, regs,
5544 &data->regs_user_copy);
5546 if (sample_type & PERF_SAMPLE_REGS_USER) {
5547 /* regs dump ABI info */
5548 int size = sizeof(u64);
5550 if (data->regs_user.regs) {
5551 u64 mask = event->attr.sample_regs_user;
5552 size += hweight64(mask) * sizeof(u64);
5555 header->size += size;
5558 if (sample_type & PERF_SAMPLE_STACK_USER) {
5560 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5561 * processed as the last one or have additional check added
5562 * in case new sample type is added, because we could eat
5563 * up the rest of the sample size.
5565 u16 stack_size = event->attr.sample_stack_user;
5566 u16 size = sizeof(u64);
5568 stack_size = perf_sample_ustack_size(stack_size, header->size,
5569 data->regs_user.regs);
5572 * If there is something to dump, add space for the dump
5573 * itself and for the field that tells the dynamic size,
5574 * which is how many have been actually dumped.
5577 size += sizeof(u64) + stack_size;
5579 data->stack_user_size = stack_size;
5580 header->size += size;
5583 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5584 /* regs dump ABI info */
5585 int size = sizeof(u64);
5587 perf_sample_regs_intr(&data->regs_intr, regs);
5589 if (data->regs_intr.regs) {
5590 u64 mask = event->attr.sample_regs_intr;
5592 size += hweight64(mask) * sizeof(u64);
5595 header->size += size;
5599 void perf_event_output(struct perf_event *event,
5600 struct perf_sample_data *data,
5601 struct pt_regs *regs)
5603 struct perf_output_handle handle;
5604 struct perf_event_header header;
5606 /* protect the callchain buffers */
5609 perf_prepare_sample(&header, data, event, regs);
5611 if (perf_output_begin(&handle, event, header.size))
5614 perf_output_sample(&handle, &header, data, event);
5616 perf_output_end(&handle);
5626 struct perf_read_event {
5627 struct perf_event_header header;
5634 perf_event_read_event(struct perf_event *event,
5635 struct task_struct *task)
5637 struct perf_output_handle handle;
5638 struct perf_sample_data sample;
5639 struct perf_read_event read_event = {
5641 .type = PERF_RECORD_READ,
5643 .size = sizeof(read_event) + event->read_size,
5645 .pid = perf_event_pid(event, task),
5646 .tid = perf_event_tid(event, task),
5650 perf_event_header__init_id(&read_event.header, &sample, event);
5651 ret = perf_output_begin(&handle, event, read_event.header.size);
5655 perf_output_put(&handle, read_event);
5656 perf_output_read(&handle, event);
5657 perf_event__output_id_sample(event, &handle, &sample);
5659 perf_output_end(&handle);
5662 typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);
5665 perf_event_aux_ctx(struct perf_event_context *ctx,
5666 perf_event_aux_output_cb output,
5669 struct perf_event *event;
5671 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5672 if (event->state < PERF_EVENT_STATE_INACTIVE)
5674 if (!event_filter_match(event))
5676 output(event, data);
5681 perf_event_aux_task_ctx(perf_event_aux_output_cb output, void *data,
5682 struct perf_event_context *task_ctx)
5686 perf_event_aux_ctx(task_ctx, output, data);
5692 perf_event_aux(perf_event_aux_output_cb output, void *data,
5693 struct perf_event_context *task_ctx)
5695 struct perf_cpu_context *cpuctx;
5696 struct perf_event_context *ctx;
5701 * If we have task_ctx != NULL we only notify
5702 * the task context itself. The task_ctx is set
5703 * only for EXIT events before releasing task
5707 perf_event_aux_task_ctx(output, data, task_ctx);
5712 list_for_each_entry_rcu(pmu, &pmus, entry) {
5713 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
5714 if (cpuctx->unique_pmu != pmu)
5716 perf_event_aux_ctx(&cpuctx->ctx, output, data);
5717 ctxn = pmu->task_ctx_nr;
5720 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
5722 perf_event_aux_ctx(ctx, output, data);
5724 put_cpu_ptr(pmu->pmu_cpu_context);
5730 * task tracking -- fork/exit
5732 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
5735 struct perf_task_event {
5736 struct task_struct *task;
5737 struct perf_event_context *task_ctx;
5740 struct perf_event_header header;
5750 static int perf_event_task_match(struct perf_event *event)
5752 return event->attr.comm || event->attr.mmap ||
5753 event->attr.mmap2 || event->attr.mmap_data ||
5757 static void perf_event_task_output(struct perf_event *event,
5760 struct perf_task_event *task_event = data;
5761 struct perf_output_handle handle;
5762 struct perf_sample_data sample;
5763 struct task_struct *task = task_event->task;
5764 int ret, size = task_event->event_id.header.size;
5766 if (!perf_event_task_match(event))
5769 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
5771 ret = perf_output_begin(&handle, event,
5772 task_event->event_id.header.size);
5776 task_event->event_id.pid = perf_event_pid(event, task);
5777 task_event->event_id.ppid = perf_event_pid(event, current);
5779 task_event->event_id.tid = perf_event_tid(event, task);
5780 task_event->event_id.ptid = perf_event_tid(event, current);
5782 task_event->event_id.time = perf_event_clock(event);
5784 perf_output_put(&handle, task_event->event_id);
5786 perf_event__output_id_sample(event, &handle, &sample);
5788 perf_output_end(&handle);
5790 task_event->event_id.header.size = size;
5793 static void perf_event_task(struct task_struct *task,
5794 struct perf_event_context *task_ctx,
5797 struct perf_task_event task_event;
5799 if (!atomic_read(&nr_comm_events) &&
5800 !atomic_read(&nr_mmap_events) &&
5801 !atomic_read(&nr_task_events))
5804 task_event = (struct perf_task_event){
5806 .task_ctx = task_ctx,
5809 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
5811 .size = sizeof(task_event.event_id),
5821 perf_event_aux(perf_event_task_output,
5826 void perf_event_fork(struct task_struct *task)
5828 perf_event_task(task, NULL, 1);
5835 struct perf_comm_event {
5836 struct task_struct *task;
5841 struct perf_event_header header;
5848 static int perf_event_comm_match(struct perf_event *event)
5850 return event->attr.comm;
5853 static void perf_event_comm_output(struct perf_event *event,
5856 struct perf_comm_event *comm_event = data;
5857 struct perf_output_handle handle;
5858 struct perf_sample_data sample;
5859 int size = comm_event->event_id.header.size;
5862 if (!perf_event_comm_match(event))
5865 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
5866 ret = perf_output_begin(&handle, event,
5867 comm_event->event_id.header.size);
5872 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
5873 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
5875 perf_output_put(&handle, comm_event->event_id);
5876 __output_copy(&handle, comm_event->comm,
5877 comm_event->comm_size);
5879 perf_event__output_id_sample(event, &handle, &sample);
5881 perf_output_end(&handle);
5883 comm_event->event_id.header.size = size;
5886 static void perf_event_comm_event(struct perf_comm_event *comm_event)
5888 char comm[TASK_COMM_LEN];
5891 memset(comm, 0, sizeof(comm));
5892 strlcpy(comm, comm_event->task->comm, sizeof(comm));
5893 size = ALIGN(strlen(comm)+1, sizeof(u64));
5895 comm_event->comm = comm;
5896 comm_event->comm_size = size;
5898 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
5900 perf_event_aux(perf_event_comm_output,
5905 void perf_event_comm(struct task_struct *task, bool exec)
5907 struct perf_comm_event comm_event;
5909 if (!atomic_read(&nr_comm_events))
5912 comm_event = (struct perf_comm_event){
5918 .type = PERF_RECORD_COMM,
5919 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
5927 perf_event_comm_event(&comm_event);
5934 struct perf_mmap_event {
5935 struct vm_area_struct *vma;
5937 const char *file_name;
5945 struct perf_event_header header;
5955 static int perf_event_mmap_match(struct perf_event *event,
5958 struct perf_mmap_event *mmap_event = data;
5959 struct vm_area_struct *vma = mmap_event->vma;
5960 int executable = vma->vm_flags & VM_EXEC;
5962 return (!executable && event->attr.mmap_data) ||
5963 (executable && (event->attr.mmap || event->attr.mmap2));
5966 static void perf_event_mmap_output(struct perf_event *event,
5969 struct perf_mmap_event *mmap_event = data;
5970 struct perf_output_handle handle;
5971 struct perf_sample_data sample;
5972 int size = mmap_event->event_id.header.size;
5975 if (!perf_event_mmap_match(event, data))
5978 if (event->attr.mmap2) {
5979 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
5980 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
5981 mmap_event->event_id.header.size += sizeof(mmap_event->min);
5982 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
5983 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
5984 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
5985 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
5988 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
5989 ret = perf_output_begin(&handle, event,
5990 mmap_event->event_id.header.size);
5994 mmap_event->event_id.pid = perf_event_pid(event, current);
5995 mmap_event->event_id.tid = perf_event_tid(event, current);
5997 perf_output_put(&handle, mmap_event->event_id);
5999 if (event->attr.mmap2) {
6000 perf_output_put(&handle, mmap_event->maj);
6001 perf_output_put(&handle, mmap_event->min);
6002 perf_output_put(&handle, mmap_event->ino);
6003 perf_output_put(&handle, mmap_event->ino_generation);
6004 perf_output_put(&handle, mmap_event->prot);
6005 perf_output_put(&handle, mmap_event->flags);
6008 __output_copy(&handle, mmap_event->file_name,
6009 mmap_event->file_size);
6011 perf_event__output_id_sample(event, &handle, &sample);
6013 perf_output_end(&handle);
6015 mmap_event->event_id.header.size = size;
6018 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6020 struct vm_area_struct *vma = mmap_event->vma;
6021 struct file *file = vma->vm_file;
6022 int maj = 0, min = 0;
6023 u64 ino = 0, gen = 0;
6024 u32 prot = 0, flags = 0;
6031 struct inode *inode;
6034 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6040 * d_path() works from the end of the rb backwards, so we
6041 * need to add enough zero bytes after the string to handle
6042 * the 64bit alignment we do later.
6044 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6049 inode = file_inode(vma->vm_file);
6050 dev = inode->i_sb->s_dev;
6052 gen = inode->i_generation;
6056 if (vma->vm_flags & VM_READ)
6058 if (vma->vm_flags & VM_WRITE)
6060 if (vma->vm_flags & VM_EXEC)
6063 if (vma->vm_flags & VM_MAYSHARE)
6066 flags = MAP_PRIVATE;
6068 if (vma->vm_flags & VM_DENYWRITE)
6069 flags |= MAP_DENYWRITE;
6070 if (vma->vm_flags & VM_MAYEXEC)
6071 flags |= MAP_EXECUTABLE;
6072 if (vma->vm_flags & VM_LOCKED)
6073 flags |= MAP_LOCKED;
6074 if (vma->vm_flags & VM_HUGETLB)
6075 flags |= MAP_HUGETLB;
6079 if (vma->vm_ops && vma->vm_ops->name) {
6080 name = (char *) vma->vm_ops->name(vma);
6085 name = (char *)arch_vma_name(vma);
6089 if (vma->vm_start <= vma->vm_mm->start_brk &&
6090 vma->vm_end >= vma->vm_mm->brk) {
6094 if (vma->vm_start <= vma->vm_mm->start_stack &&
6095 vma->vm_end >= vma->vm_mm->start_stack) {
6105 strlcpy(tmp, name, sizeof(tmp));
6109 * Since our buffer works in 8 byte units we need to align our string
6110 * size to a multiple of 8. However, we must guarantee the tail end is
6111 * zero'd out to avoid leaking random bits to userspace.
6113 size = strlen(name)+1;
6114 while (!IS_ALIGNED(size, sizeof(u64)))
6115 name[size++] = '\0';
6117 mmap_event->file_name = name;
6118 mmap_event->file_size = size;
6119 mmap_event->maj = maj;
6120 mmap_event->min = min;
6121 mmap_event->ino = ino;
6122 mmap_event->ino_generation = gen;
6123 mmap_event->prot = prot;
6124 mmap_event->flags = flags;
6126 if (!(vma->vm_flags & VM_EXEC))
6127 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6129 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6131 perf_event_aux(perf_event_mmap_output,
6138 void perf_event_mmap(struct vm_area_struct *vma)
6140 struct perf_mmap_event mmap_event;
6142 if (!atomic_read(&nr_mmap_events))
6145 mmap_event = (struct perf_mmap_event){
6151 .type = PERF_RECORD_MMAP,
6152 .misc = PERF_RECORD_MISC_USER,
6157 .start = vma->vm_start,
6158 .len = vma->vm_end - vma->vm_start,
6159 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6161 /* .maj (attr_mmap2 only) */
6162 /* .min (attr_mmap2 only) */
6163 /* .ino (attr_mmap2 only) */
6164 /* .ino_generation (attr_mmap2 only) */
6165 /* .prot (attr_mmap2 only) */
6166 /* .flags (attr_mmap2 only) */
6169 perf_event_mmap_event(&mmap_event);
6172 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6173 unsigned long size, u64 flags)
6175 struct perf_output_handle handle;
6176 struct perf_sample_data sample;
6177 struct perf_aux_event {
6178 struct perf_event_header header;
6184 .type = PERF_RECORD_AUX,
6186 .size = sizeof(rec),
6194 perf_event_header__init_id(&rec.header, &sample, event);
6195 ret = perf_output_begin(&handle, event, rec.header.size);
6200 perf_output_put(&handle, rec);
6201 perf_event__output_id_sample(event, &handle, &sample);
6203 perf_output_end(&handle);
6207 * Lost/dropped samples logging
6209 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6211 struct perf_output_handle handle;
6212 struct perf_sample_data sample;
6216 struct perf_event_header header;
6218 } lost_samples_event = {
6220 .type = PERF_RECORD_LOST_SAMPLES,
6222 .size = sizeof(lost_samples_event),
6227 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6229 ret = perf_output_begin(&handle, event,
6230 lost_samples_event.header.size);
6234 perf_output_put(&handle, lost_samples_event);
6235 perf_event__output_id_sample(event, &handle, &sample);
6236 perf_output_end(&handle);
6240 * context_switch tracking
6243 struct perf_switch_event {
6244 struct task_struct *task;
6245 struct task_struct *next_prev;
6248 struct perf_event_header header;
6254 static int perf_event_switch_match(struct perf_event *event)
6256 return event->attr.context_switch;
6259 static void perf_event_switch_output(struct perf_event *event, void *data)
6261 struct perf_switch_event *se = data;
6262 struct perf_output_handle handle;
6263 struct perf_sample_data sample;
6266 if (!perf_event_switch_match(event))
6269 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6270 if (event->ctx->task) {
6271 se->event_id.header.type = PERF_RECORD_SWITCH;
6272 se->event_id.header.size = sizeof(se->event_id.header);
6274 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6275 se->event_id.header.size = sizeof(se->event_id);
6276 se->event_id.next_prev_pid =
6277 perf_event_pid(event, se->next_prev);
6278 se->event_id.next_prev_tid =
6279 perf_event_tid(event, se->next_prev);
6282 perf_event_header__init_id(&se->event_id.header, &sample, event);
6284 ret = perf_output_begin(&handle, event, se->event_id.header.size);
6288 if (event->ctx->task)
6289 perf_output_put(&handle, se->event_id.header);
6291 perf_output_put(&handle, se->event_id);
6293 perf_event__output_id_sample(event, &handle, &sample);
6295 perf_output_end(&handle);
6298 static void perf_event_switch(struct task_struct *task,
6299 struct task_struct *next_prev, bool sched_in)
6301 struct perf_switch_event switch_event;
6303 /* N.B. caller checks nr_switch_events != 0 */
6305 switch_event = (struct perf_switch_event){
6307 .next_prev = next_prev,
6311 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6314 /* .next_prev_pid */
6315 /* .next_prev_tid */
6319 perf_event_aux(perf_event_switch_output,
6325 * IRQ throttle logging
6328 static void perf_log_throttle(struct perf_event *event, int enable)
6330 struct perf_output_handle handle;
6331 struct perf_sample_data sample;
6335 struct perf_event_header header;
6339 } throttle_event = {
6341 .type = PERF_RECORD_THROTTLE,
6343 .size = sizeof(throttle_event),
6345 .time = perf_event_clock(event),
6346 .id = primary_event_id(event),
6347 .stream_id = event->id,
6351 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6353 perf_event_header__init_id(&throttle_event.header, &sample, event);
6355 ret = perf_output_begin(&handle, event,
6356 throttle_event.header.size);
6360 perf_output_put(&handle, throttle_event);
6361 perf_event__output_id_sample(event, &handle, &sample);
6362 perf_output_end(&handle);
6365 static void perf_log_itrace_start(struct perf_event *event)
6367 struct perf_output_handle handle;
6368 struct perf_sample_data sample;
6369 struct perf_aux_event {
6370 struct perf_event_header header;
6377 event = event->parent;
6379 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
6380 event->hw.itrace_started)
6383 rec.header.type = PERF_RECORD_ITRACE_START;
6384 rec.header.misc = 0;
6385 rec.header.size = sizeof(rec);
6386 rec.pid = perf_event_pid(event, current);
6387 rec.tid = perf_event_tid(event, current);
6389 perf_event_header__init_id(&rec.header, &sample, event);
6390 ret = perf_output_begin(&handle, event, rec.header.size);
6395 perf_output_put(&handle, rec);
6396 perf_event__output_id_sample(event, &handle, &sample);
6398 perf_output_end(&handle);
6402 * Generic event overflow handling, sampling.
6405 static int __perf_event_overflow(struct perf_event *event,
6406 int throttle, struct perf_sample_data *data,
6407 struct pt_regs *regs)
6409 int events = atomic_read(&event->event_limit);
6410 struct hw_perf_event *hwc = &event->hw;
6415 * Non-sampling counters might still use the PMI to fold short
6416 * hardware counters, ignore those.
6418 if (unlikely(!is_sampling_event(event)))
6421 seq = __this_cpu_read(perf_throttled_seq);
6422 if (seq != hwc->interrupts_seq) {
6423 hwc->interrupts_seq = seq;
6424 hwc->interrupts = 1;
6427 if (unlikely(throttle
6428 && hwc->interrupts >= max_samples_per_tick)) {
6429 __this_cpu_inc(perf_throttled_count);
6430 hwc->interrupts = MAX_INTERRUPTS;
6431 perf_log_throttle(event, 0);
6432 tick_nohz_full_kick();
6437 if (event->attr.freq) {
6438 u64 now = perf_clock();
6439 s64 delta = now - hwc->freq_time_stamp;
6441 hwc->freq_time_stamp = now;
6443 if (delta > 0 && delta < 2*TICK_NSEC)
6444 perf_adjust_period(event, delta, hwc->last_period, true);
6448 * XXX event_limit might not quite work as expected on inherited
6452 event->pending_kill = POLL_IN;
6453 if (events && atomic_dec_and_test(&event->event_limit)) {
6455 event->pending_kill = POLL_HUP;
6456 event->pending_disable = 1;
6457 irq_work_queue(&event->pending);
6460 if (event->overflow_handler)
6461 event->overflow_handler(event, data, regs);
6463 perf_event_output(event, data, regs);
6465 if (*perf_event_fasync(event) && event->pending_kill) {
6466 event->pending_wakeup = 1;
6467 irq_work_queue(&event->pending);
6473 int perf_event_overflow(struct perf_event *event,
6474 struct perf_sample_data *data,
6475 struct pt_regs *regs)
6477 return __perf_event_overflow(event, 1, data, regs);
6481 * Generic software event infrastructure
6484 struct swevent_htable {
6485 struct swevent_hlist *swevent_hlist;
6486 struct mutex hlist_mutex;
6489 /* Recursion avoidance in each contexts */
6490 int recursion[PERF_NR_CONTEXTS];
6493 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
6496 * We directly increment event->count and keep a second value in
6497 * event->hw.period_left to count intervals. This period event
6498 * is kept in the range [-sample_period, 0] so that we can use the
6502 u64 perf_swevent_set_period(struct perf_event *event)
6504 struct hw_perf_event *hwc = &event->hw;
6505 u64 period = hwc->last_period;
6509 hwc->last_period = hwc->sample_period;
6512 old = val = local64_read(&hwc->period_left);
6516 nr = div64_u64(period + val, period);
6517 offset = nr * period;
6519 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
6525 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
6526 struct perf_sample_data *data,
6527 struct pt_regs *regs)
6529 struct hw_perf_event *hwc = &event->hw;
6533 overflow = perf_swevent_set_period(event);
6535 if (hwc->interrupts == MAX_INTERRUPTS)
6538 for (; overflow; overflow--) {
6539 if (__perf_event_overflow(event, throttle,
6542 * We inhibit the overflow from happening when
6543 * hwc->interrupts == MAX_INTERRUPTS.
6551 static void perf_swevent_event(struct perf_event *event, u64 nr,
6552 struct perf_sample_data *data,
6553 struct pt_regs *regs)
6555 struct hw_perf_event *hwc = &event->hw;
6557 local64_add(nr, &event->count);
6562 if (!is_sampling_event(event))
6565 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
6567 return perf_swevent_overflow(event, 1, data, regs);
6569 data->period = event->hw.last_period;
6571 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
6572 return perf_swevent_overflow(event, 1, data, regs);
6574 if (local64_add_negative(nr, &hwc->period_left))
6577 perf_swevent_overflow(event, 0, data, regs);
6580 static int perf_exclude_event(struct perf_event *event,
6581 struct pt_regs *regs)
6583 if (event->hw.state & PERF_HES_STOPPED)
6587 if (event->attr.exclude_user && user_mode(regs))
6590 if (event->attr.exclude_kernel && !user_mode(regs))
6597 static int perf_swevent_match(struct perf_event *event,
6598 enum perf_type_id type,
6600 struct perf_sample_data *data,
6601 struct pt_regs *regs)
6603 if (event->attr.type != type)
6606 if (event->attr.config != event_id)
6609 if (perf_exclude_event(event, regs))
6615 static inline u64 swevent_hash(u64 type, u32 event_id)
6617 u64 val = event_id | (type << 32);
6619 return hash_64(val, SWEVENT_HLIST_BITS);
6622 static inline struct hlist_head *
6623 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
6625 u64 hash = swevent_hash(type, event_id);
6627 return &hlist->heads[hash];
6630 /* For the read side: events when they trigger */
6631 static inline struct hlist_head *
6632 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
6634 struct swevent_hlist *hlist;
6636 hlist = rcu_dereference(swhash->swevent_hlist);
6640 return __find_swevent_head(hlist, type, event_id);
6643 /* For the event head insertion and removal in the hlist */
6644 static inline struct hlist_head *
6645 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
6647 struct swevent_hlist *hlist;
6648 u32 event_id = event->attr.config;
6649 u64 type = event->attr.type;
6652 * Event scheduling is always serialized against hlist allocation
6653 * and release. Which makes the protected version suitable here.
6654 * The context lock guarantees that.
6656 hlist = rcu_dereference_protected(swhash->swevent_hlist,
6657 lockdep_is_held(&event->ctx->lock));
6661 return __find_swevent_head(hlist, type, event_id);
6664 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
6666 struct perf_sample_data *data,
6667 struct pt_regs *regs)
6669 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6670 struct perf_event *event;
6671 struct hlist_head *head;
6674 head = find_swevent_head_rcu(swhash, type, event_id);
6678 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6679 if (perf_swevent_match(event, type, event_id, data, regs))
6680 perf_swevent_event(event, nr, data, regs);
6686 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
6688 int perf_swevent_get_recursion_context(void)
6690 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6692 return get_recursion_context(swhash->recursion);
6694 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
6696 inline void perf_swevent_put_recursion_context(int rctx)
6698 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6700 put_recursion_context(swhash->recursion, rctx);
6703 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6705 struct perf_sample_data data;
6707 if (WARN_ON_ONCE(!regs))
6710 perf_sample_data_init(&data, addr, 0);
6711 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
6714 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6718 preempt_disable_notrace();
6719 rctx = perf_swevent_get_recursion_context();
6720 if (unlikely(rctx < 0))
6723 ___perf_sw_event(event_id, nr, regs, addr);
6725 perf_swevent_put_recursion_context(rctx);
6727 preempt_enable_notrace();
6730 static void perf_swevent_read(struct perf_event *event)
6734 static int perf_swevent_add(struct perf_event *event, int flags)
6736 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6737 struct hw_perf_event *hwc = &event->hw;
6738 struct hlist_head *head;
6740 if (is_sampling_event(event)) {
6741 hwc->last_period = hwc->sample_period;
6742 perf_swevent_set_period(event);
6745 hwc->state = !(flags & PERF_EF_START);
6747 head = find_swevent_head(swhash, event);
6748 if (WARN_ON_ONCE(!head))
6751 hlist_add_head_rcu(&event->hlist_entry, head);
6752 perf_event_update_userpage(event);
6757 static void perf_swevent_del(struct perf_event *event, int flags)
6759 hlist_del_rcu(&event->hlist_entry);
6762 static void perf_swevent_start(struct perf_event *event, int flags)
6764 event->hw.state = 0;
6767 static void perf_swevent_stop(struct perf_event *event, int flags)
6769 event->hw.state = PERF_HES_STOPPED;
6772 /* Deref the hlist from the update side */
6773 static inline struct swevent_hlist *
6774 swevent_hlist_deref(struct swevent_htable *swhash)
6776 return rcu_dereference_protected(swhash->swevent_hlist,
6777 lockdep_is_held(&swhash->hlist_mutex));
6780 static void swevent_hlist_release(struct swevent_htable *swhash)
6782 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
6787 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
6788 kfree_rcu(hlist, rcu_head);
6791 static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
6793 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6795 mutex_lock(&swhash->hlist_mutex);
6797 if (!--swhash->hlist_refcount)
6798 swevent_hlist_release(swhash);
6800 mutex_unlock(&swhash->hlist_mutex);
6803 static void swevent_hlist_put(struct perf_event *event)
6807 for_each_possible_cpu(cpu)
6808 swevent_hlist_put_cpu(event, cpu);
6811 static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
6813 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6816 mutex_lock(&swhash->hlist_mutex);
6817 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
6818 struct swevent_hlist *hlist;
6820 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
6825 rcu_assign_pointer(swhash->swevent_hlist, hlist);
6827 swhash->hlist_refcount++;
6829 mutex_unlock(&swhash->hlist_mutex);
6834 static int swevent_hlist_get(struct perf_event *event)
6837 int cpu, failed_cpu;
6840 for_each_possible_cpu(cpu) {
6841 err = swevent_hlist_get_cpu(event, cpu);
6851 for_each_possible_cpu(cpu) {
6852 if (cpu == failed_cpu)
6854 swevent_hlist_put_cpu(event, cpu);
6861 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
6863 static void sw_perf_event_destroy(struct perf_event *event)
6865 u64 event_id = event->attr.config;
6867 WARN_ON(event->parent);
6869 static_key_slow_dec(&perf_swevent_enabled[event_id]);
6870 swevent_hlist_put(event);
6873 static int perf_swevent_init(struct perf_event *event)
6875 u64 event_id = event->attr.config;
6877 if (event->attr.type != PERF_TYPE_SOFTWARE)
6881 * no branch sampling for software events
6883 if (has_branch_stack(event))
6887 case PERF_COUNT_SW_CPU_CLOCK:
6888 case PERF_COUNT_SW_TASK_CLOCK:
6895 if (event_id >= PERF_COUNT_SW_MAX)
6898 if (!event->parent) {
6901 err = swevent_hlist_get(event);
6905 static_key_slow_inc(&perf_swevent_enabled[event_id]);
6906 event->destroy = sw_perf_event_destroy;
6912 static struct pmu perf_swevent = {
6913 .task_ctx_nr = perf_sw_context,
6915 .capabilities = PERF_PMU_CAP_NO_NMI,
6917 .event_init = perf_swevent_init,
6918 .add = perf_swevent_add,
6919 .del = perf_swevent_del,
6920 .start = perf_swevent_start,
6921 .stop = perf_swevent_stop,
6922 .read = perf_swevent_read,
6925 #ifdef CONFIG_EVENT_TRACING
6927 static int perf_tp_filter_match(struct perf_event *event,
6928 struct perf_sample_data *data)
6930 void *record = data->raw->data;
6932 /* only top level events have filters set */
6934 event = event->parent;
6936 if (likely(!event->filter) || filter_match_preds(event->filter, record))
6941 static int perf_tp_event_match(struct perf_event *event,
6942 struct perf_sample_data *data,
6943 struct pt_regs *regs)
6945 if (event->hw.state & PERF_HES_STOPPED)
6948 * All tracepoints are from kernel-space.
6950 if (event->attr.exclude_kernel)
6953 if (!perf_tp_filter_match(event, data))
6959 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
6960 struct pt_regs *regs, struct hlist_head *head, int rctx,
6961 struct task_struct *task)
6963 struct perf_sample_data data;
6964 struct perf_event *event;
6966 struct perf_raw_record raw = {
6971 perf_sample_data_init(&data, addr, 0);
6974 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6975 if (perf_tp_event_match(event, &data, regs))
6976 perf_swevent_event(event, count, &data, regs);
6980 * If we got specified a target task, also iterate its context and
6981 * deliver this event there too.
6983 if (task && task != current) {
6984 struct perf_event_context *ctx;
6985 struct trace_entry *entry = record;
6988 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
6992 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6993 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6995 if (event->attr.config != entry->type)
6997 if (perf_tp_event_match(event, &data, regs))
6998 perf_swevent_event(event, count, &data, regs);
7004 perf_swevent_put_recursion_context(rctx);
7006 EXPORT_SYMBOL_GPL(perf_tp_event);
7008 static void tp_perf_event_destroy(struct perf_event *event)
7010 perf_trace_destroy(event);
7013 static int perf_tp_event_init(struct perf_event *event)
7017 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7021 * no branch sampling for tracepoint events
7023 if (has_branch_stack(event))
7026 err = perf_trace_init(event);
7030 event->destroy = tp_perf_event_destroy;
7035 static struct pmu perf_tracepoint = {
7036 .task_ctx_nr = perf_sw_context,
7038 .event_init = perf_tp_event_init,
7039 .add = perf_trace_add,
7040 .del = perf_trace_del,
7041 .start = perf_swevent_start,
7042 .stop = perf_swevent_stop,
7043 .read = perf_swevent_read,
7046 static inline void perf_tp_register(void)
7048 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7051 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7056 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7059 filter_str = strndup_user(arg, PAGE_SIZE);
7060 if (IS_ERR(filter_str))
7061 return PTR_ERR(filter_str);
7063 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
7069 static void perf_event_free_filter(struct perf_event *event)
7071 ftrace_profile_free_filter(event);
7074 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7076 struct bpf_prog *prog;
7078 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7081 if (event->tp_event->prog)
7084 if (!(event->tp_event->flags & TRACE_EVENT_FL_UKPROBE))
7085 /* bpf programs can only be attached to u/kprobes */
7088 prog = bpf_prog_get(prog_fd);
7090 return PTR_ERR(prog);
7092 if (prog->type != BPF_PROG_TYPE_KPROBE) {
7093 /* valid fd, but invalid bpf program type */
7098 event->tp_event->prog = prog;
7103 static void perf_event_free_bpf_prog(struct perf_event *event)
7105 struct bpf_prog *prog;
7107 if (!event->tp_event)
7110 prog = event->tp_event->prog;
7112 event->tp_event->prog = NULL;
7119 static inline void perf_tp_register(void)
7123 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7128 static void perf_event_free_filter(struct perf_event *event)
7132 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7137 static void perf_event_free_bpf_prog(struct perf_event *event)
7140 #endif /* CONFIG_EVENT_TRACING */
7142 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7143 void perf_bp_event(struct perf_event *bp, void *data)
7145 struct perf_sample_data sample;
7146 struct pt_regs *regs = data;
7148 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7150 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7151 perf_swevent_event(bp, 1, &sample, regs);
7156 * hrtimer based swevent callback
7159 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
7161 enum hrtimer_restart ret = HRTIMER_RESTART;
7162 struct perf_sample_data data;
7163 struct pt_regs *regs;
7164 struct perf_event *event;
7167 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
7169 if (event->state != PERF_EVENT_STATE_ACTIVE)
7170 return HRTIMER_NORESTART;
7172 event->pmu->read(event);
7174 perf_sample_data_init(&data, 0, event->hw.last_period);
7175 regs = get_irq_regs();
7177 if (regs && !perf_exclude_event(event, regs)) {
7178 if (!(event->attr.exclude_idle && is_idle_task(current)))
7179 if (__perf_event_overflow(event, 1, &data, regs))
7180 ret = HRTIMER_NORESTART;
7183 period = max_t(u64, 10000, event->hw.sample_period);
7184 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
7189 static void perf_swevent_start_hrtimer(struct perf_event *event)
7191 struct hw_perf_event *hwc = &event->hw;
7194 if (!is_sampling_event(event))
7197 period = local64_read(&hwc->period_left);
7202 local64_set(&hwc->period_left, 0);
7204 period = max_t(u64, 10000, hwc->sample_period);
7206 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
7207 HRTIMER_MODE_REL_PINNED);
7210 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
7212 struct hw_perf_event *hwc = &event->hw;
7214 if (is_sampling_event(event)) {
7215 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
7216 local64_set(&hwc->period_left, ktime_to_ns(remaining));
7218 hrtimer_cancel(&hwc->hrtimer);
7222 static void perf_swevent_init_hrtimer(struct perf_event *event)
7224 struct hw_perf_event *hwc = &event->hw;
7226 if (!is_sampling_event(event))
7229 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
7230 hwc->hrtimer.function = perf_swevent_hrtimer;
7233 * Since hrtimers have a fixed rate, we can do a static freq->period
7234 * mapping and avoid the whole period adjust feedback stuff.
7236 if (event->attr.freq) {
7237 long freq = event->attr.sample_freq;
7239 event->attr.sample_period = NSEC_PER_SEC / freq;
7240 hwc->sample_period = event->attr.sample_period;
7241 local64_set(&hwc->period_left, hwc->sample_period);
7242 hwc->last_period = hwc->sample_period;
7243 event->attr.freq = 0;
7248 * Software event: cpu wall time clock
7251 static void cpu_clock_event_update(struct perf_event *event)
7256 now = local_clock();
7257 prev = local64_xchg(&event->hw.prev_count, now);
7258 local64_add(now - prev, &event->count);
7261 static void cpu_clock_event_start(struct perf_event *event, int flags)
7263 local64_set(&event->hw.prev_count, local_clock());
7264 perf_swevent_start_hrtimer(event);
7267 static void cpu_clock_event_stop(struct perf_event *event, int flags)
7269 perf_swevent_cancel_hrtimer(event);
7270 cpu_clock_event_update(event);
7273 static int cpu_clock_event_add(struct perf_event *event, int flags)
7275 if (flags & PERF_EF_START)
7276 cpu_clock_event_start(event, flags);
7277 perf_event_update_userpage(event);
7282 static void cpu_clock_event_del(struct perf_event *event, int flags)
7284 cpu_clock_event_stop(event, flags);
7287 static void cpu_clock_event_read(struct perf_event *event)
7289 cpu_clock_event_update(event);
7292 static int cpu_clock_event_init(struct perf_event *event)
7294 if (event->attr.type != PERF_TYPE_SOFTWARE)
7297 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
7301 * no branch sampling for software events
7303 if (has_branch_stack(event))
7306 perf_swevent_init_hrtimer(event);
7311 static struct pmu perf_cpu_clock = {
7312 .task_ctx_nr = perf_sw_context,
7314 .capabilities = PERF_PMU_CAP_NO_NMI,
7316 .event_init = cpu_clock_event_init,
7317 .add = cpu_clock_event_add,
7318 .del = cpu_clock_event_del,
7319 .start = cpu_clock_event_start,
7320 .stop = cpu_clock_event_stop,
7321 .read = cpu_clock_event_read,
7325 * Software event: task time clock
7328 static void task_clock_event_update(struct perf_event *event, u64 now)
7333 prev = local64_xchg(&event->hw.prev_count, now);
7335 local64_add(delta, &event->count);
7338 static void task_clock_event_start(struct perf_event *event, int flags)
7340 local64_set(&event->hw.prev_count, event->ctx->time);
7341 perf_swevent_start_hrtimer(event);
7344 static void task_clock_event_stop(struct perf_event *event, int flags)
7346 perf_swevent_cancel_hrtimer(event);
7347 task_clock_event_update(event, event->ctx->time);
7350 static int task_clock_event_add(struct perf_event *event, int flags)
7352 if (flags & PERF_EF_START)
7353 task_clock_event_start(event, flags);
7354 perf_event_update_userpage(event);
7359 static void task_clock_event_del(struct perf_event *event, int flags)
7361 task_clock_event_stop(event, PERF_EF_UPDATE);
7364 static void task_clock_event_read(struct perf_event *event)
7366 u64 now = perf_clock();
7367 u64 delta = now - event->ctx->timestamp;
7368 u64 time = event->ctx->time + delta;
7370 task_clock_event_update(event, time);
7373 static int task_clock_event_init(struct perf_event *event)
7375 if (event->attr.type != PERF_TYPE_SOFTWARE)
7378 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
7382 * no branch sampling for software events
7384 if (has_branch_stack(event))
7387 perf_swevent_init_hrtimer(event);
7392 static struct pmu perf_task_clock = {
7393 .task_ctx_nr = perf_sw_context,
7395 .capabilities = PERF_PMU_CAP_NO_NMI,
7397 .event_init = task_clock_event_init,
7398 .add = task_clock_event_add,
7399 .del = task_clock_event_del,
7400 .start = task_clock_event_start,
7401 .stop = task_clock_event_stop,
7402 .read = task_clock_event_read,
7405 static void perf_pmu_nop_void(struct pmu *pmu)
7409 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
7413 static int perf_pmu_nop_int(struct pmu *pmu)
7418 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
7420 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
7422 __this_cpu_write(nop_txn_flags, flags);
7424 if (flags & ~PERF_PMU_TXN_ADD)
7427 perf_pmu_disable(pmu);
7430 static int perf_pmu_commit_txn(struct pmu *pmu)
7432 unsigned int flags = __this_cpu_read(nop_txn_flags);
7434 __this_cpu_write(nop_txn_flags, 0);
7436 if (flags & ~PERF_PMU_TXN_ADD)
7439 perf_pmu_enable(pmu);
7443 static void perf_pmu_cancel_txn(struct pmu *pmu)
7445 unsigned int flags = __this_cpu_read(nop_txn_flags);
7447 __this_cpu_write(nop_txn_flags, 0);
7449 if (flags & ~PERF_PMU_TXN_ADD)
7452 perf_pmu_enable(pmu);
7455 static int perf_event_idx_default(struct perf_event *event)
7461 * Ensures all contexts with the same task_ctx_nr have the same
7462 * pmu_cpu_context too.
7464 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
7471 list_for_each_entry(pmu, &pmus, entry) {
7472 if (pmu->task_ctx_nr == ctxn)
7473 return pmu->pmu_cpu_context;
7479 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
7483 for_each_possible_cpu(cpu) {
7484 struct perf_cpu_context *cpuctx;
7486 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7488 if (cpuctx->unique_pmu == old_pmu)
7489 cpuctx->unique_pmu = pmu;
7493 static void free_pmu_context(struct pmu *pmu)
7497 mutex_lock(&pmus_lock);
7499 * Like a real lame refcount.
7501 list_for_each_entry(i, &pmus, entry) {
7502 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
7503 update_pmu_context(i, pmu);
7508 free_percpu(pmu->pmu_cpu_context);
7510 mutex_unlock(&pmus_lock);
7512 static struct idr pmu_idr;
7515 type_show(struct device *dev, struct device_attribute *attr, char *page)
7517 struct pmu *pmu = dev_get_drvdata(dev);
7519 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
7521 static DEVICE_ATTR_RO(type);
7524 perf_event_mux_interval_ms_show(struct device *dev,
7525 struct device_attribute *attr,
7528 struct pmu *pmu = dev_get_drvdata(dev);
7530 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
7533 static DEFINE_MUTEX(mux_interval_mutex);
7536 perf_event_mux_interval_ms_store(struct device *dev,
7537 struct device_attribute *attr,
7538 const char *buf, size_t count)
7540 struct pmu *pmu = dev_get_drvdata(dev);
7541 int timer, cpu, ret;
7543 ret = kstrtoint(buf, 0, &timer);
7550 /* same value, noting to do */
7551 if (timer == pmu->hrtimer_interval_ms)
7554 mutex_lock(&mux_interval_mutex);
7555 pmu->hrtimer_interval_ms = timer;
7557 /* update all cpuctx for this PMU */
7559 for_each_online_cpu(cpu) {
7560 struct perf_cpu_context *cpuctx;
7561 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7562 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
7564 cpu_function_call(cpu,
7565 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
7568 mutex_unlock(&mux_interval_mutex);
7572 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
7574 static struct attribute *pmu_dev_attrs[] = {
7575 &dev_attr_type.attr,
7576 &dev_attr_perf_event_mux_interval_ms.attr,
7579 ATTRIBUTE_GROUPS(pmu_dev);
7581 static int pmu_bus_running;
7582 static struct bus_type pmu_bus = {
7583 .name = "event_source",
7584 .dev_groups = pmu_dev_groups,
7587 static void pmu_dev_release(struct device *dev)
7592 static int pmu_dev_alloc(struct pmu *pmu)
7596 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
7600 pmu->dev->groups = pmu->attr_groups;
7601 device_initialize(pmu->dev);
7602 ret = dev_set_name(pmu->dev, "%s", pmu->name);
7606 dev_set_drvdata(pmu->dev, pmu);
7607 pmu->dev->bus = &pmu_bus;
7608 pmu->dev->release = pmu_dev_release;
7609 ret = device_add(pmu->dev);
7617 put_device(pmu->dev);
7621 static struct lock_class_key cpuctx_mutex;
7622 static struct lock_class_key cpuctx_lock;
7624 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
7628 mutex_lock(&pmus_lock);
7630 pmu->pmu_disable_count = alloc_percpu(int);
7631 if (!pmu->pmu_disable_count)
7640 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
7648 if (pmu_bus_running) {
7649 ret = pmu_dev_alloc(pmu);
7655 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
7656 if (pmu->pmu_cpu_context)
7657 goto got_cpu_context;
7660 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
7661 if (!pmu->pmu_cpu_context)
7664 for_each_possible_cpu(cpu) {
7665 struct perf_cpu_context *cpuctx;
7667 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7668 __perf_event_init_context(&cpuctx->ctx);
7669 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
7670 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
7671 cpuctx->ctx.pmu = pmu;
7673 __perf_mux_hrtimer_init(cpuctx, cpu);
7675 cpuctx->unique_pmu = pmu;
7679 if (!pmu->start_txn) {
7680 if (pmu->pmu_enable) {
7682 * If we have pmu_enable/pmu_disable calls, install
7683 * transaction stubs that use that to try and batch
7684 * hardware accesses.
7686 pmu->start_txn = perf_pmu_start_txn;
7687 pmu->commit_txn = perf_pmu_commit_txn;
7688 pmu->cancel_txn = perf_pmu_cancel_txn;
7690 pmu->start_txn = perf_pmu_nop_txn;
7691 pmu->commit_txn = perf_pmu_nop_int;
7692 pmu->cancel_txn = perf_pmu_nop_void;
7696 if (!pmu->pmu_enable) {
7697 pmu->pmu_enable = perf_pmu_nop_void;
7698 pmu->pmu_disable = perf_pmu_nop_void;
7701 if (!pmu->event_idx)
7702 pmu->event_idx = perf_event_idx_default;
7704 list_add_rcu(&pmu->entry, &pmus);
7705 atomic_set(&pmu->exclusive_cnt, 0);
7708 mutex_unlock(&pmus_lock);
7713 device_del(pmu->dev);
7714 put_device(pmu->dev);
7717 if (pmu->type >= PERF_TYPE_MAX)
7718 idr_remove(&pmu_idr, pmu->type);
7721 free_percpu(pmu->pmu_disable_count);
7724 EXPORT_SYMBOL_GPL(perf_pmu_register);
7726 void perf_pmu_unregister(struct pmu *pmu)
7728 mutex_lock(&pmus_lock);
7729 list_del_rcu(&pmu->entry);
7730 mutex_unlock(&pmus_lock);
7733 * We dereference the pmu list under both SRCU and regular RCU, so
7734 * synchronize against both of those.
7736 synchronize_srcu(&pmus_srcu);
7739 free_percpu(pmu->pmu_disable_count);
7740 if (pmu->type >= PERF_TYPE_MAX)
7741 idr_remove(&pmu_idr, pmu->type);
7742 device_del(pmu->dev);
7743 put_device(pmu->dev);
7744 free_pmu_context(pmu);
7746 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
7748 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
7750 struct perf_event_context *ctx = NULL;
7753 if (!try_module_get(pmu->module))
7756 if (event->group_leader != event) {
7758 * This ctx->mutex can nest when we're called through
7759 * inheritance. See the perf_event_ctx_lock_nested() comment.
7761 ctx = perf_event_ctx_lock_nested(event->group_leader,
7762 SINGLE_DEPTH_NESTING);
7767 ret = pmu->event_init(event);
7770 perf_event_ctx_unlock(event->group_leader, ctx);
7773 module_put(pmu->module);
7778 static struct pmu *perf_init_event(struct perf_event *event)
7780 struct pmu *pmu = NULL;
7784 idx = srcu_read_lock(&pmus_srcu);
7787 pmu = idr_find(&pmu_idr, event->attr.type);
7790 ret = perf_try_init_event(pmu, event);
7796 list_for_each_entry_rcu(pmu, &pmus, entry) {
7797 ret = perf_try_init_event(pmu, event);
7801 if (ret != -ENOENT) {
7806 pmu = ERR_PTR(-ENOENT);
7808 srcu_read_unlock(&pmus_srcu, idx);
7813 static void account_event_cpu(struct perf_event *event, int cpu)
7818 if (is_cgroup_event(event))
7819 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
7822 static void account_event(struct perf_event *event)
7827 if (event->attach_state & PERF_ATTACH_TASK)
7828 static_key_slow_inc(&perf_sched_events.key);
7829 if (event->attr.mmap || event->attr.mmap_data)
7830 atomic_inc(&nr_mmap_events);
7831 if (event->attr.comm)
7832 atomic_inc(&nr_comm_events);
7833 if (event->attr.task)
7834 atomic_inc(&nr_task_events);
7835 if (event->attr.freq) {
7836 if (atomic_inc_return(&nr_freq_events) == 1)
7837 tick_nohz_full_kick_all();
7839 if (event->attr.context_switch) {
7840 atomic_inc(&nr_switch_events);
7841 static_key_slow_inc(&perf_sched_events.key);
7843 if (has_branch_stack(event))
7844 static_key_slow_inc(&perf_sched_events.key);
7845 if (is_cgroup_event(event))
7846 static_key_slow_inc(&perf_sched_events.key);
7848 account_event_cpu(event, event->cpu);
7852 * Allocate and initialize a event structure
7854 static struct perf_event *
7855 perf_event_alloc(struct perf_event_attr *attr, int cpu,
7856 struct task_struct *task,
7857 struct perf_event *group_leader,
7858 struct perf_event *parent_event,
7859 perf_overflow_handler_t overflow_handler,
7860 void *context, int cgroup_fd)
7863 struct perf_event *event;
7864 struct hw_perf_event *hwc;
7867 if ((unsigned)cpu >= nr_cpu_ids) {
7868 if (!task || cpu != -1)
7869 return ERR_PTR(-EINVAL);
7872 event = kzalloc(sizeof(*event), GFP_KERNEL);
7874 return ERR_PTR(-ENOMEM);
7877 * Single events are their own group leaders, with an
7878 * empty sibling list:
7881 group_leader = event;
7883 mutex_init(&event->child_mutex);
7884 INIT_LIST_HEAD(&event->child_list);
7886 INIT_LIST_HEAD(&event->group_entry);
7887 INIT_LIST_HEAD(&event->event_entry);
7888 INIT_LIST_HEAD(&event->sibling_list);
7889 INIT_LIST_HEAD(&event->rb_entry);
7890 INIT_LIST_HEAD(&event->active_entry);
7891 INIT_HLIST_NODE(&event->hlist_entry);
7894 init_waitqueue_head(&event->waitq);
7895 init_irq_work(&event->pending, perf_pending_event);
7897 mutex_init(&event->mmap_mutex);
7899 atomic_long_set(&event->refcount, 1);
7901 event->attr = *attr;
7902 event->group_leader = group_leader;
7906 event->parent = parent_event;
7908 event->ns = get_pid_ns(task_active_pid_ns(current));
7909 event->id = atomic64_inc_return(&perf_event_id);
7911 event->state = PERF_EVENT_STATE_INACTIVE;
7914 event->attach_state = PERF_ATTACH_TASK;
7916 * XXX pmu::event_init needs to know what task to account to
7917 * and we cannot use the ctx information because we need the
7918 * pmu before we get a ctx.
7920 event->hw.target = task;
7923 event->clock = &local_clock;
7925 event->clock = parent_event->clock;
7927 if (!overflow_handler && parent_event) {
7928 overflow_handler = parent_event->overflow_handler;
7929 context = parent_event->overflow_handler_context;
7932 event->overflow_handler = overflow_handler;
7933 event->overflow_handler_context = context;
7935 perf_event__state_init(event);
7940 hwc->sample_period = attr->sample_period;
7941 if (attr->freq && attr->sample_freq)
7942 hwc->sample_period = 1;
7943 hwc->last_period = hwc->sample_period;
7945 local64_set(&hwc->period_left, hwc->sample_period);
7948 * we currently do not support PERF_FORMAT_GROUP on inherited events
7950 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
7953 if (!has_branch_stack(event))
7954 event->attr.branch_sample_type = 0;
7956 if (cgroup_fd != -1) {
7957 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
7962 pmu = perf_init_event(event);
7965 else if (IS_ERR(pmu)) {
7970 err = exclusive_event_init(event);
7974 if (!event->parent) {
7975 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
7976 err = get_callchain_buffers();
7982 /* symmetric to unaccount_event() in _free_event() */
7983 account_event(event);
7988 exclusive_event_destroy(event);
7992 event->destroy(event);
7993 module_put(pmu->module);
7995 if (is_cgroup_event(event))
7996 perf_detach_cgroup(event);
7998 put_pid_ns(event->ns);
8001 return ERR_PTR(err);
8004 static int perf_copy_attr(struct perf_event_attr __user *uattr,
8005 struct perf_event_attr *attr)
8010 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
8014 * zero the full structure, so that a short copy will be nice.
8016 memset(attr, 0, sizeof(*attr));
8018 ret = get_user(size, &uattr->size);
8022 if (size > PAGE_SIZE) /* silly large */
8025 if (!size) /* abi compat */
8026 size = PERF_ATTR_SIZE_VER0;
8028 if (size < PERF_ATTR_SIZE_VER0)
8032 * If we're handed a bigger struct than we know of,
8033 * ensure all the unknown bits are 0 - i.e. new
8034 * user-space does not rely on any kernel feature
8035 * extensions we dont know about yet.
8037 if (size > sizeof(*attr)) {
8038 unsigned char __user *addr;
8039 unsigned char __user *end;
8042 addr = (void __user *)uattr + sizeof(*attr);
8043 end = (void __user *)uattr + size;
8045 for (; addr < end; addr++) {
8046 ret = get_user(val, addr);
8052 size = sizeof(*attr);
8055 ret = copy_from_user(attr, uattr, size);
8059 if (attr->__reserved_1)
8062 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
8065 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
8068 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
8069 u64 mask = attr->branch_sample_type;
8071 /* only using defined bits */
8072 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
8075 /* at least one branch bit must be set */
8076 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
8079 /* propagate priv level, when not set for branch */
8080 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
8082 /* exclude_kernel checked on syscall entry */
8083 if (!attr->exclude_kernel)
8084 mask |= PERF_SAMPLE_BRANCH_KERNEL;
8086 if (!attr->exclude_user)
8087 mask |= PERF_SAMPLE_BRANCH_USER;
8089 if (!attr->exclude_hv)
8090 mask |= PERF_SAMPLE_BRANCH_HV;
8092 * adjust user setting (for HW filter setup)
8094 attr->branch_sample_type = mask;
8096 /* privileged levels capture (kernel, hv): check permissions */
8097 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
8098 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8102 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
8103 ret = perf_reg_validate(attr->sample_regs_user);
8108 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
8109 if (!arch_perf_have_user_stack_dump())
8113 * We have __u32 type for the size, but so far
8114 * we can only use __u16 as maximum due to the
8115 * __u16 sample size limit.
8117 if (attr->sample_stack_user >= USHRT_MAX)
8119 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
8123 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
8124 ret = perf_reg_validate(attr->sample_regs_intr);
8129 put_user(sizeof(*attr), &uattr->size);
8135 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
8137 struct ring_buffer *rb = NULL;
8143 /* don't allow circular references */
8144 if (event == output_event)
8148 * Don't allow cross-cpu buffers
8150 if (output_event->cpu != event->cpu)
8154 * If its not a per-cpu rb, it must be the same task.
8156 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
8160 * Mixing clocks in the same buffer is trouble you don't need.
8162 if (output_event->clock != event->clock)
8166 * If both events generate aux data, they must be on the same PMU
8168 if (has_aux(event) && has_aux(output_event) &&
8169 event->pmu != output_event->pmu)
8173 mutex_lock(&event->mmap_mutex);
8174 /* Can't redirect output if we've got an active mmap() */
8175 if (atomic_read(&event->mmap_count))
8179 /* get the rb we want to redirect to */
8180 rb = ring_buffer_get(output_event);
8185 ring_buffer_attach(event, rb);
8189 mutex_unlock(&event->mmap_mutex);
8195 static void mutex_lock_double(struct mutex *a, struct mutex *b)
8201 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
8204 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
8206 bool nmi_safe = false;
8209 case CLOCK_MONOTONIC:
8210 event->clock = &ktime_get_mono_fast_ns;
8214 case CLOCK_MONOTONIC_RAW:
8215 event->clock = &ktime_get_raw_fast_ns;
8219 case CLOCK_REALTIME:
8220 event->clock = &ktime_get_real_ns;
8223 case CLOCK_BOOTTIME:
8224 event->clock = &ktime_get_boot_ns;
8228 event->clock = &ktime_get_tai_ns;
8235 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
8242 * sys_perf_event_open - open a performance event, associate it to a task/cpu
8244 * @attr_uptr: event_id type attributes for monitoring/sampling
8247 * @group_fd: group leader event fd
8249 SYSCALL_DEFINE5(perf_event_open,
8250 struct perf_event_attr __user *, attr_uptr,
8251 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
8253 struct perf_event *group_leader = NULL, *output_event = NULL;
8254 struct perf_event *event, *sibling;
8255 struct perf_event_attr attr;
8256 struct perf_event_context *ctx, *uninitialized_var(gctx);
8257 struct file *event_file = NULL;
8258 struct fd group = {NULL, 0};
8259 struct task_struct *task = NULL;
8264 int f_flags = O_RDWR;
8267 /* for future expandability... */
8268 if (flags & ~PERF_FLAG_ALL)
8271 err = perf_copy_attr(attr_uptr, &attr);
8275 if (!attr.exclude_kernel) {
8276 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8281 if (attr.sample_freq > sysctl_perf_event_sample_rate)
8284 if (attr.sample_period & (1ULL << 63))
8289 * In cgroup mode, the pid argument is used to pass the fd
8290 * opened to the cgroup directory in cgroupfs. The cpu argument
8291 * designates the cpu on which to monitor threads from that
8294 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
8297 if (flags & PERF_FLAG_FD_CLOEXEC)
8298 f_flags |= O_CLOEXEC;
8300 event_fd = get_unused_fd_flags(f_flags);
8304 if (group_fd != -1) {
8305 err = perf_fget_light(group_fd, &group);
8308 group_leader = group.file->private_data;
8309 if (flags & PERF_FLAG_FD_OUTPUT)
8310 output_event = group_leader;
8311 if (flags & PERF_FLAG_FD_NO_GROUP)
8312 group_leader = NULL;
8315 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
8316 task = find_lively_task_by_vpid(pid);
8318 err = PTR_ERR(task);
8323 if (task && group_leader &&
8324 group_leader->attr.inherit != attr.inherit) {
8331 if (flags & PERF_FLAG_PID_CGROUP)
8334 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
8335 NULL, NULL, cgroup_fd);
8336 if (IS_ERR(event)) {
8337 err = PTR_ERR(event);
8341 if (is_sampling_event(event)) {
8342 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
8349 * Special case software events and allow them to be part of
8350 * any hardware group.
8354 if (attr.use_clockid) {
8355 err = perf_event_set_clock(event, attr.clockid);
8361 (is_software_event(event) != is_software_event(group_leader))) {
8362 if (is_software_event(event)) {
8364 * If event and group_leader are not both a software
8365 * event, and event is, then group leader is not.
8367 * Allow the addition of software events to !software
8368 * groups, this is safe because software events never
8371 pmu = group_leader->pmu;
8372 } else if (is_software_event(group_leader) &&
8373 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
8375 * In case the group is a pure software group, and we
8376 * try to add a hardware event, move the whole group to
8377 * the hardware context.
8384 * Get the target context (task or percpu):
8386 ctx = find_get_context(pmu, task, event);
8392 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
8398 put_task_struct(task);
8403 * Look up the group leader (we will attach this event to it):
8409 * Do not allow a recursive hierarchy (this new sibling
8410 * becoming part of another group-sibling):
8412 if (group_leader->group_leader != group_leader)
8415 /* All events in a group should have the same clock */
8416 if (group_leader->clock != event->clock)
8420 * Do not allow to attach to a group in a different
8421 * task or CPU context:
8425 * Make sure we're both on the same task, or both
8428 if (group_leader->ctx->task != ctx->task)
8432 * Make sure we're both events for the same CPU;
8433 * grouping events for different CPUs is broken; since
8434 * you can never concurrently schedule them anyhow.
8436 if (group_leader->cpu != event->cpu)
8439 if (group_leader->ctx != ctx)
8444 * Only a group leader can be exclusive or pinned
8446 if (attr.exclusive || attr.pinned)
8451 err = perf_event_set_output(event, output_event);
8456 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
8458 if (IS_ERR(event_file)) {
8459 err = PTR_ERR(event_file);
8464 gctx = group_leader->ctx;
8465 mutex_lock_double(&gctx->mutex, &ctx->mutex);
8467 mutex_lock(&ctx->mutex);
8470 if (!perf_event_validate_size(event)) {
8476 * Must be under the same ctx::mutex as perf_install_in_context(),
8477 * because we need to serialize with concurrent event creation.
8479 if (!exclusive_event_installable(event, ctx)) {
8480 /* exclusive and group stuff are assumed mutually exclusive */
8481 WARN_ON_ONCE(move_group);
8487 WARN_ON_ONCE(ctx->parent_ctx);
8491 * See perf_event_ctx_lock() for comments on the details
8492 * of swizzling perf_event::ctx.
8494 perf_remove_from_context(group_leader, false);
8496 list_for_each_entry(sibling, &group_leader->sibling_list,
8498 perf_remove_from_context(sibling, false);
8503 * Wait for everybody to stop referencing the events through
8504 * the old lists, before installing it on new lists.
8509 * Install the group siblings before the group leader.
8511 * Because a group leader will try and install the entire group
8512 * (through the sibling list, which is still in-tact), we can
8513 * end up with siblings installed in the wrong context.
8515 * By installing siblings first we NO-OP because they're not
8516 * reachable through the group lists.
8518 list_for_each_entry(sibling, &group_leader->sibling_list,
8520 perf_event__state_init(sibling);
8521 perf_install_in_context(ctx, sibling, sibling->cpu);
8526 * Removing from the context ends up with disabled
8527 * event. What we want here is event in the initial
8528 * startup state, ready to be add into new context.
8530 perf_event__state_init(group_leader);
8531 perf_install_in_context(ctx, group_leader, group_leader->cpu);
8535 * Now that all events are installed in @ctx, nothing
8536 * references @gctx anymore, so drop the last reference we have
8543 * Precalculate sample_data sizes; do while holding ctx::mutex such
8544 * that we're serialized against further additions and before
8545 * perf_install_in_context() which is the point the event is active and
8546 * can use these values.
8548 perf_event__header_size(event);
8549 perf_event__id_header_size(event);
8551 perf_install_in_context(ctx, event, event->cpu);
8552 perf_unpin_context(ctx);
8555 mutex_unlock(&gctx->mutex);
8556 mutex_unlock(&ctx->mutex);
8560 event->owner = current;
8562 mutex_lock(¤t->perf_event_mutex);
8563 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
8564 mutex_unlock(¤t->perf_event_mutex);
8567 * Drop the reference on the group_event after placing the
8568 * new event on the sibling_list. This ensures destruction
8569 * of the group leader will find the pointer to itself in
8570 * perf_group_detach().
8573 fd_install(event_fd, event_file);
8578 mutex_unlock(&gctx->mutex);
8579 mutex_unlock(&ctx->mutex);
8583 perf_unpin_context(ctx);
8591 put_task_struct(task);
8595 put_unused_fd(event_fd);
8600 * perf_event_create_kernel_counter
8602 * @attr: attributes of the counter to create
8603 * @cpu: cpu in which the counter is bound
8604 * @task: task to profile (NULL for percpu)
8607 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
8608 struct task_struct *task,
8609 perf_overflow_handler_t overflow_handler,
8612 struct perf_event_context *ctx;
8613 struct perf_event *event;
8617 * Get the target context (task or percpu):
8620 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
8621 overflow_handler, context, -1);
8622 if (IS_ERR(event)) {
8623 err = PTR_ERR(event);
8627 /* Mark owner so we could distinguish it from user events. */
8628 event->owner = EVENT_OWNER_KERNEL;
8630 ctx = find_get_context(event->pmu, task, event);
8636 WARN_ON_ONCE(ctx->parent_ctx);
8637 mutex_lock(&ctx->mutex);
8638 if (!exclusive_event_installable(event, ctx)) {
8639 mutex_unlock(&ctx->mutex);
8640 perf_unpin_context(ctx);
8646 perf_install_in_context(ctx, event, cpu);
8647 perf_unpin_context(ctx);
8648 mutex_unlock(&ctx->mutex);
8655 return ERR_PTR(err);
8657 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
8659 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
8661 struct perf_event_context *src_ctx;
8662 struct perf_event_context *dst_ctx;
8663 struct perf_event *event, *tmp;
8666 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
8667 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
8670 * See perf_event_ctx_lock() for comments on the details
8671 * of swizzling perf_event::ctx.
8673 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
8674 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
8676 perf_remove_from_context(event, false);
8677 unaccount_event_cpu(event, src_cpu);
8679 list_add(&event->migrate_entry, &events);
8683 * Wait for the events to quiesce before re-instating them.
8688 * Re-instate events in 2 passes.
8690 * Skip over group leaders and only install siblings on this first
8691 * pass, siblings will not get enabled without a leader, however a
8692 * leader will enable its siblings, even if those are still on the old
8695 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8696 if (event->group_leader == event)
8699 list_del(&event->migrate_entry);
8700 if (event->state >= PERF_EVENT_STATE_OFF)
8701 event->state = PERF_EVENT_STATE_INACTIVE;
8702 account_event_cpu(event, dst_cpu);
8703 perf_install_in_context(dst_ctx, event, dst_cpu);
8708 * Once all the siblings are setup properly, install the group leaders
8711 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8712 list_del(&event->migrate_entry);
8713 if (event->state >= PERF_EVENT_STATE_OFF)
8714 event->state = PERF_EVENT_STATE_INACTIVE;
8715 account_event_cpu(event, dst_cpu);
8716 perf_install_in_context(dst_ctx, event, dst_cpu);
8719 mutex_unlock(&dst_ctx->mutex);
8720 mutex_unlock(&src_ctx->mutex);
8722 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
8724 static void sync_child_event(struct perf_event *child_event,
8725 struct task_struct *child)
8727 struct perf_event *parent_event = child_event->parent;
8730 if (child_event->attr.inherit_stat)
8731 perf_event_read_event(child_event, child);
8733 child_val = perf_event_count(child_event);
8736 * Add back the child's count to the parent's count:
8738 atomic64_add(child_val, &parent_event->child_count);
8739 atomic64_add(child_event->total_time_enabled,
8740 &parent_event->child_total_time_enabled);
8741 atomic64_add(child_event->total_time_running,
8742 &parent_event->child_total_time_running);
8745 * Remove this event from the parent's list
8747 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
8748 mutex_lock(&parent_event->child_mutex);
8749 list_del_init(&child_event->child_list);
8750 mutex_unlock(&parent_event->child_mutex);
8753 * Make sure user/parent get notified, that we just
8756 perf_event_wakeup(parent_event);
8759 * Release the parent event, if this was the last
8762 put_event(parent_event);
8766 __perf_event_exit_task(struct perf_event *child_event,
8767 struct perf_event_context *child_ctx,
8768 struct task_struct *child)
8771 * Do not destroy the 'original' grouping; because of the context
8772 * switch optimization the original events could've ended up in a
8773 * random child task.
8775 * If we were to destroy the original group, all group related
8776 * operations would cease to function properly after this random
8779 * Do destroy all inherited groups, we don't care about those
8780 * and being thorough is better.
8782 perf_remove_from_context(child_event, !!child_event->parent);
8785 * It can happen that the parent exits first, and has events
8786 * that are still around due to the child reference. These
8787 * events need to be zapped.
8789 if (child_event->parent) {
8790 sync_child_event(child_event, child);
8791 free_event(child_event);
8793 child_event->state = PERF_EVENT_STATE_EXIT;
8794 perf_event_wakeup(child_event);
8798 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
8800 struct perf_event *child_event, *next;
8801 struct perf_event_context *child_ctx, *clone_ctx = NULL;
8802 unsigned long flags;
8804 if (likely(!child->perf_event_ctxp[ctxn]))
8807 local_irq_save(flags);
8809 * We can't reschedule here because interrupts are disabled,
8810 * and either child is current or it is a task that can't be
8811 * scheduled, so we are now safe from rescheduling changing
8814 child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);
8817 * Take the context lock here so that if find_get_context is
8818 * reading child->perf_event_ctxp, we wait until it has
8819 * incremented the context's refcount before we do put_ctx below.
8821 raw_spin_lock(&child_ctx->lock);
8822 task_ctx_sched_out(child_ctx);
8823 child->perf_event_ctxp[ctxn] = NULL;
8826 * If this context is a clone; unclone it so it can't get
8827 * swapped to another process while we're removing all
8828 * the events from it.
8830 clone_ctx = unclone_ctx(child_ctx);
8831 update_context_time(child_ctx);
8832 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
8838 * Report the task dead after unscheduling the events so that we
8839 * won't get any samples after PERF_RECORD_EXIT. We can however still
8840 * get a few PERF_RECORD_READ events.
8842 perf_event_task(child, child_ctx, 0);
8845 * We can recurse on the same lock type through:
8847 * __perf_event_exit_task()
8848 * sync_child_event()
8850 * mutex_lock(&ctx->mutex)
8852 * But since its the parent context it won't be the same instance.
8854 mutex_lock(&child_ctx->mutex);
8856 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
8857 __perf_event_exit_task(child_event, child_ctx, child);
8859 mutex_unlock(&child_ctx->mutex);
8865 * When a child task exits, feed back event values to parent events.
8867 void perf_event_exit_task(struct task_struct *child)
8869 struct perf_event *event, *tmp;
8872 mutex_lock(&child->perf_event_mutex);
8873 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
8875 list_del_init(&event->owner_entry);
8878 * Ensure the list deletion is visible before we clear
8879 * the owner, closes a race against perf_release() where
8880 * we need to serialize on the owner->perf_event_mutex.
8883 event->owner = NULL;
8885 mutex_unlock(&child->perf_event_mutex);
8887 for_each_task_context_nr(ctxn)
8888 perf_event_exit_task_context(child, ctxn);
8891 * The perf_event_exit_task_context calls perf_event_task
8892 * with child's task_ctx, which generates EXIT events for
8893 * child contexts and sets child->perf_event_ctxp[] to NULL.
8894 * At this point we need to send EXIT events to cpu contexts.
8896 perf_event_task(child, NULL, 0);
8899 static void perf_free_event(struct perf_event *event,
8900 struct perf_event_context *ctx)
8902 struct perf_event *parent = event->parent;
8904 if (WARN_ON_ONCE(!parent))
8907 mutex_lock(&parent->child_mutex);
8908 list_del_init(&event->child_list);
8909 mutex_unlock(&parent->child_mutex);
8913 raw_spin_lock_irq(&ctx->lock);
8914 perf_group_detach(event);
8915 list_del_event(event, ctx);
8916 raw_spin_unlock_irq(&ctx->lock);
8921 * Free an unexposed, unused context as created by inheritance by
8922 * perf_event_init_task below, used by fork() in case of fail.
8924 * Not all locks are strictly required, but take them anyway to be nice and
8925 * help out with the lockdep assertions.
8927 void perf_event_free_task(struct task_struct *task)
8929 struct perf_event_context *ctx;
8930 struct perf_event *event, *tmp;
8933 for_each_task_context_nr(ctxn) {
8934 ctx = task->perf_event_ctxp[ctxn];
8938 mutex_lock(&ctx->mutex);
8940 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
8942 perf_free_event(event, ctx);
8944 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
8946 perf_free_event(event, ctx);
8948 if (!list_empty(&ctx->pinned_groups) ||
8949 !list_empty(&ctx->flexible_groups))
8952 mutex_unlock(&ctx->mutex);
8958 void perf_event_delayed_put(struct task_struct *task)
8962 for_each_task_context_nr(ctxn)
8963 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
8966 struct perf_event *perf_event_get(unsigned int fd)
8970 struct perf_event *event;
8972 err = perf_fget_light(fd, &f);
8974 return ERR_PTR(err);
8976 event = f.file->private_data;
8977 atomic_long_inc(&event->refcount);
8983 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
8986 return ERR_PTR(-EINVAL);
8988 return &event->attr;
8992 * inherit a event from parent task to child task:
8994 static struct perf_event *
8995 inherit_event(struct perf_event *parent_event,
8996 struct task_struct *parent,
8997 struct perf_event_context *parent_ctx,
8998 struct task_struct *child,
8999 struct perf_event *group_leader,
9000 struct perf_event_context *child_ctx)
9002 enum perf_event_active_state parent_state = parent_event->state;
9003 struct perf_event *child_event;
9004 unsigned long flags;
9007 * Instead of creating recursive hierarchies of events,
9008 * we link inherited events back to the original parent,
9009 * which has a filp for sure, which we use as the reference
9012 if (parent_event->parent)
9013 parent_event = parent_event->parent;
9015 child_event = perf_event_alloc(&parent_event->attr,
9018 group_leader, parent_event,
9020 if (IS_ERR(child_event))
9023 if (is_orphaned_event(parent_event) ||
9024 !atomic_long_inc_not_zero(&parent_event->refcount)) {
9025 free_event(child_event);
9032 * Make the child state follow the state of the parent event,
9033 * not its attr.disabled bit. We hold the parent's mutex,
9034 * so we won't race with perf_event_{en, dis}able_family.
9036 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
9037 child_event->state = PERF_EVENT_STATE_INACTIVE;
9039 child_event->state = PERF_EVENT_STATE_OFF;
9041 if (parent_event->attr.freq) {
9042 u64 sample_period = parent_event->hw.sample_period;
9043 struct hw_perf_event *hwc = &child_event->hw;
9045 hwc->sample_period = sample_period;
9046 hwc->last_period = sample_period;
9048 local64_set(&hwc->period_left, sample_period);
9051 child_event->ctx = child_ctx;
9052 child_event->overflow_handler = parent_event->overflow_handler;
9053 child_event->overflow_handler_context
9054 = parent_event->overflow_handler_context;
9057 * Precalculate sample_data sizes
9059 perf_event__header_size(child_event);
9060 perf_event__id_header_size(child_event);
9063 * Link it up in the child's context:
9065 raw_spin_lock_irqsave(&child_ctx->lock, flags);
9066 add_event_to_ctx(child_event, child_ctx);
9067 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
9070 * Link this into the parent event's child list
9072 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
9073 mutex_lock(&parent_event->child_mutex);
9074 list_add_tail(&child_event->child_list, &parent_event->child_list);
9075 mutex_unlock(&parent_event->child_mutex);
9080 static int inherit_group(struct perf_event *parent_event,
9081 struct task_struct *parent,
9082 struct perf_event_context *parent_ctx,
9083 struct task_struct *child,
9084 struct perf_event_context *child_ctx)
9086 struct perf_event *leader;
9087 struct perf_event *sub;
9088 struct perf_event *child_ctr;
9090 leader = inherit_event(parent_event, parent, parent_ctx,
9091 child, NULL, child_ctx);
9093 return PTR_ERR(leader);
9094 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
9095 child_ctr = inherit_event(sub, parent, parent_ctx,
9096 child, leader, child_ctx);
9097 if (IS_ERR(child_ctr))
9098 return PTR_ERR(child_ctr);
9104 inherit_task_group(struct perf_event *event, struct task_struct *parent,
9105 struct perf_event_context *parent_ctx,
9106 struct task_struct *child, int ctxn,
9110 struct perf_event_context *child_ctx;
9112 if (!event->attr.inherit) {
9117 child_ctx = child->perf_event_ctxp[ctxn];
9120 * This is executed from the parent task context, so
9121 * inherit events that have been marked for cloning.
9122 * First allocate and initialize a context for the
9126 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
9130 child->perf_event_ctxp[ctxn] = child_ctx;
9133 ret = inherit_group(event, parent, parent_ctx,
9143 * Initialize the perf_event context in task_struct
9145 static int perf_event_init_context(struct task_struct *child, int ctxn)
9147 struct perf_event_context *child_ctx, *parent_ctx;
9148 struct perf_event_context *cloned_ctx;
9149 struct perf_event *event;
9150 struct task_struct *parent = current;
9151 int inherited_all = 1;
9152 unsigned long flags;
9155 if (likely(!parent->perf_event_ctxp[ctxn]))
9159 * If the parent's context is a clone, pin it so it won't get
9162 parent_ctx = perf_pin_task_context(parent, ctxn);
9167 * No need to check if parent_ctx != NULL here; since we saw
9168 * it non-NULL earlier, the only reason for it to become NULL
9169 * is if we exit, and since we're currently in the middle of
9170 * a fork we can't be exiting at the same time.
9174 * Lock the parent list. No need to lock the child - not PID
9175 * hashed yet and not running, so nobody can access it.
9177 mutex_lock(&parent_ctx->mutex);
9180 * We dont have to disable NMIs - we are only looking at
9181 * the list, not manipulating it:
9183 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
9184 ret = inherit_task_group(event, parent, parent_ctx,
9185 child, ctxn, &inherited_all);
9191 * We can't hold ctx->lock when iterating the ->flexible_group list due
9192 * to allocations, but we need to prevent rotation because
9193 * rotate_ctx() will change the list from interrupt context.
9195 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9196 parent_ctx->rotate_disable = 1;
9197 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9199 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
9200 ret = inherit_task_group(event, parent, parent_ctx,
9201 child, ctxn, &inherited_all);
9206 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9207 parent_ctx->rotate_disable = 0;
9209 child_ctx = child->perf_event_ctxp[ctxn];
9211 if (child_ctx && inherited_all) {
9213 * Mark the child context as a clone of the parent
9214 * context, or of whatever the parent is a clone of.
9216 * Note that if the parent is a clone, the holding of
9217 * parent_ctx->lock avoids it from being uncloned.
9219 cloned_ctx = parent_ctx->parent_ctx;
9221 child_ctx->parent_ctx = cloned_ctx;
9222 child_ctx->parent_gen = parent_ctx->parent_gen;
9224 child_ctx->parent_ctx = parent_ctx;
9225 child_ctx->parent_gen = parent_ctx->generation;
9227 get_ctx(child_ctx->parent_ctx);
9230 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9231 mutex_unlock(&parent_ctx->mutex);
9233 perf_unpin_context(parent_ctx);
9234 put_ctx(parent_ctx);
9240 * Initialize the perf_event context in task_struct
9242 int perf_event_init_task(struct task_struct *child)
9246 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
9247 mutex_init(&child->perf_event_mutex);
9248 INIT_LIST_HEAD(&child->perf_event_list);
9250 for_each_task_context_nr(ctxn) {
9251 ret = perf_event_init_context(child, ctxn);
9253 perf_event_free_task(child);
9261 static void __init perf_event_init_all_cpus(void)
9263 struct swevent_htable *swhash;
9266 for_each_possible_cpu(cpu) {
9267 swhash = &per_cpu(swevent_htable, cpu);
9268 mutex_init(&swhash->hlist_mutex);
9269 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
9273 static void perf_event_init_cpu(int cpu)
9275 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9277 mutex_lock(&swhash->hlist_mutex);
9278 if (swhash->hlist_refcount > 0) {
9279 struct swevent_hlist *hlist;
9281 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
9283 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9285 mutex_unlock(&swhash->hlist_mutex);
9288 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
9289 static void __perf_event_exit_context(void *__info)
9291 struct remove_event re = { .detach_group = true };
9292 struct perf_event_context *ctx = __info;
9295 list_for_each_entry_rcu(re.event, &ctx->event_list, event_entry)
9296 __perf_remove_from_context(&re);
9300 static void perf_event_exit_cpu_context(int cpu)
9302 struct perf_event_context *ctx;
9306 idx = srcu_read_lock(&pmus_srcu);
9307 list_for_each_entry_rcu(pmu, &pmus, entry) {
9308 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
9310 mutex_lock(&ctx->mutex);
9311 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
9312 mutex_unlock(&ctx->mutex);
9314 srcu_read_unlock(&pmus_srcu, idx);
9317 static void perf_event_exit_cpu(int cpu)
9319 perf_event_exit_cpu_context(cpu);
9322 static inline void perf_event_exit_cpu(int cpu) { }
9326 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
9330 for_each_online_cpu(cpu)
9331 perf_event_exit_cpu(cpu);
9337 * Run the perf reboot notifier at the very last possible moment so that
9338 * the generic watchdog code runs as long as possible.
9340 static struct notifier_block perf_reboot_notifier = {
9341 .notifier_call = perf_reboot,
9342 .priority = INT_MIN,
9346 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
9348 unsigned int cpu = (long)hcpu;
9350 switch (action & ~CPU_TASKS_FROZEN) {
9352 case CPU_UP_PREPARE:
9353 case CPU_DOWN_FAILED:
9354 perf_event_init_cpu(cpu);
9357 case CPU_UP_CANCELED:
9358 case CPU_DOWN_PREPARE:
9359 perf_event_exit_cpu(cpu);
9368 void __init perf_event_init(void)
9374 perf_event_init_all_cpus();
9375 init_srcu_struct(&pmus_srcu);
9376 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
9377 perf_pmu_register(&perf_cpu_clock, NULL, -1);
9378 perf_pmu_register(&perf_task_clock, NULL, -1);
9380 perf_cpu_notifier(perf_cpu_notify);
9381 register_reboot_notifier(&perf_reboot_notifier);
9383 ret = init_hw_breakpoint();
9384 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
9386 /* do not patch jump label more than once per second */
9387 jump_label_rate_limit(&perf_sched_events, HZ);
9390 * Build time assertion that we keep the data_head at the intended
9391 * location. IOW, validation we got the __reserved[] size right.
9393 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
9397 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
9400 struct perf_pmu_events_attr *pmu_attr =
9401 container_of(attr, struct perf_pmu_events_attr, attr);
9403 if (pmu_attr->event_str)
9404 return sprintf(page, "%s\n", pmu_attr->event_str);
9409 static int __init perf_event_sysfs_init(void)
9414 mutex_lock(&pmus_lock);
9416 ret = bus_register(&pmu_bus);
9420 list_for_each_entry(pmu, &pmus, entry) {
9421 if (!pmu->name || pmu->type < 0)
9424 ret = pmu_dev_alloc(pmu);
9425 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
9427 pmu_bus_running = 1;
9431 mutex_unlock(&pmus_lock);
9435 device_initcall(perf_event_sysfs_init);
9437 #ifdef CONFIG_CGROUP_PERF
9438 static struct cgroup_subsys_state *
9439 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
9441 struct perf_cgroup *jc;
9443 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
9445 return ERR_PTR(-ENOMEM);
9447 jc->info = alloc_percpu(struct perf_cgroup_info);
9450 return ERR_PTR(-ENOMEM);
9456 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
9458 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
9460 free_percpu(jc->info);
9464 static int __perf_cgroup_move(void *info)
9466 struct task_struct *task = info;
9468 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
9473 static void perf_cgroup_attach(struct cgroup_taskset *tset)
9475 struct task_struct *task;
9476 struct cgroup_subsys_state *css;
9478 cgroup_taskset_for_each(task, css, tset)
9479 task_function_call(task, __perf_cgroup_move, task);
9482 struct cgroup_subsys perf_event_cgrp_subsys = {
9483 .css_alloc = perf_cgroup_css_alloc,
9484 .css_free = perf_cgroup_css_free,
9485 .attach = perf_cgroup_attach,
9487 #endif /* CONFIG_CGROUP_PERF */