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Root/kernel/perf_event.c

1	/*
2	* Performance events core code:
3	*
4	* Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5	* Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
6	* Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
7	* Copyright � 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
8	*
9	* For licensing details see kernel-base/COPYING
10	*/
11
12	#include <linux/fs.h>
13	#include <linux/mm.h>
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/sysfs.h>
22	#include <linux/dcache.h>
23	#include <linux/percpu.h>
24	#include <linux/ptrace.h>
25	#include <linux/reboot.h>
26	#include <linux/vmstat.h>
27	#include <linux/device.h>
28	#include <linux/vmalloc.h>
29	#include <linux/hardirq.h>
30	#include <linux/rculist.h>
31	#include <linux/uaccess.h>
32	#include <linux/syscalls.h>
33	#include <linux/anon_inodes.h>
34	#include <linux/kernel_stat.h>
35	#include <linux/perf_event.h>
36	#include <linux/ftrace_event.h>
37	#include <linux/hw_breakpoint.h>
38
39	#include <asm/irq_regs.h>
40
41	enum event_type_t {
42	EVENT_FLEXIBLE = 0x1,
43	EVENT_PINNED = 0x2,
44	EVENT_ALL = EVENT_FLEXIBLE \| EVENT_PINNED,
45	};
46
47	atomic_t perf_task_events __read_mostly;
48	static atomic_t nr_mmap_events __read_mostly;
49	static atomic_t nr_comm_events __read_mostly;
50	static atomic_t nr_task_events __read_mostly;
51
52	static LIST_HEAD(pmus);
53	static DEFINE_MUTEX(pmus_lock);
54	static struct srcu_struct pmus_srcu;
55
56	/*
57	* perf event paranoia level:
58	* -1 - not paranoid at all
59	* 0 - disallow raw tracepoint access for unpriv
60	* 1 - disallow cpu events for unpriv
61	* 2 - disallow kernel profiling for unpriv
62	*/
63	int sysctl_perf_event_paranoid __read_mostly = 1;
64
65	int sysctl_perf_event_mlock __read_mostly = 512; /* 'free' kb per user */
66
67	/*
68	* max perf event sample rate
69	*/
70	int sysctl_perf_event_sample_rate __read_mostly = 100000;
71
72	static atomic64_t perf_event_id;
73
74	static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
75	enum event_type_t event_type);
76
77	static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
78	enum event_type_t event_type);
79
80	void __weak perf_event_print_debug(void) { }
81
82	extern __weak const char *perf_pmu_name(void)
83	{
84	return "pmu";
85	}
86
87	static inline u64 perf_clock(void)
88	{
89	return local_clock();
90	}
91
92	void perf_pmu_disable(struct pmu *pmu)
93	{
94	int *count = this_cpu_ptr(pmu->pmu_disable_count);
95	if (!(*count)++)
96	pmu->pmu_disable(pmu);
97	}
98
99	void perf_pmu_enable(struct pmu *pmu)
100	{
101	int *count = this_cpu_ptr(pmu->pmu_disable_count);
102	if (!--(*count))
103	pmu->pmu_enable(pmu);
104	}
105
106	static DEFINE_PER_CPU(struct list_head, rotation_list);
107
108	/*
109	* perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
110	* because they're strictly cpu affine and rotate_start is called with IRQs
111	* disabled, while rotate_context is called from IRQ context.
112	*/
113	static void perf_pmu_rotate_start(struct pmu *pmu)
114	{
115	struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
116	struct list_head *head = &__get_cpu_var(rotation_list);
117
118	WARN_ON(!irqs_disabled());
119
120	if (list_empty(&cpuctx->rotation_list))
121	list_add(&cpuctx->rotation_list, head);
122	}
123
124	static void get_ctx(struct perf_event_context *ctx)
125	{
126	WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
127	}
128
129	static void free_ctx(struct rcu_head *head)
130	{
131	struct perf_event_context *ctx;
132
133	ctx = container_of(head, struct perf_event_context, rcu_head);
134	kfree(ctx);
135	}
136
137	static void put_ctx(struct perf_event_context *ctx)
138	{
139	if (atomic_dec_and_test(&ctx->refcount)) {
140	if (ctx->parent_ctx)
141	put_ctx(ctx->parent_ctx);
142	if (ctx->task)
143	put_task_struct(ctx->task);
144	call_rcu(&ctx->rcu_head, free_ctx);
145	}
146	}
147
148	static void unclone_ctx(struct perf_event_context *ctx)
149	{
150	if (ctx->parent_ctx) {
151	put_ctx(ctx->parent_ctx);
152	ctx->parent_ctx = NULL;
153	}
154	}
155
156	static u32 perf_event_pid(struct perf_event event, struct task_struct p)
157	{
158	/*
159	* only top level events have the pid namespace they were created in
160	*/
161	if (event->parent)
162	event = event->parent;
163
164	return task_tgid_nr_ns(p, event->ns);
165	}
166
167	static u32 perf_event_tid(struct perf_event event, struct task_struct p)
168	{
169	/*
170	* only top level events have the pid namespace they were created in
171	*/
172	if (event->parent)
173	event = event->parent;
174
175	return task_pid_nr_ns(p, event->ns);
176	}
177
178	/*
179	* If we inherit events we want to return the parent event id
180	* to userspace.
181	*/
182	static u64 primary_event_id(struct perf_event *event)
183	{
184	u64 id = event->id;
185
186	if (event->parent)
187	id = event->parent->id;
188
189	return id;
190	}
191
192	/*
193	* Get the perf_event_context for a task and lock it.
194	* This has to cope with with the fact that until it is locked,
195	* the context could get moved to another task.
196	*/
197	static struct perf_event_context *
198	perf_lock_task_context(struct task_struct task, int ctxn, unsigned long flags)
199	{
200	struct perf_event_context *ctx;
201
202	rcu_read_lock();
203	retry:
204	ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
205	if (ctx) {
206	/*
207	* If this context is a clone of another, it might
208	* get swapped for another underneath us by
209	* perf_event_task_sched_out, though the
210	* rcu_read_lock() protects us from any context
211	* getting freed. Lock the context and check if it
212	* got swapped before we could get the lock, and retry
213	* if so. If we locked the right context, then it
214	* can't get swapped on us any more.
215	*/
216	raw_spin_lock_irqsave(&ctx->lock, *flags);
217	if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
218	raw_spin_unlock_irqrestore(&ctx->lock, *flags);
219	goto retry;
220	}
221
222	if (!atomic_inc_not_zero(&ctx->refcount)) {
223	raw_spin_unlock_irqrestore(&ctx->lock, *flags);
224	ctx = NULL;
225	}
226	}
227	rcu_read_unlock();
228	return ctx;
229	}
230
231	/*
232	* Get the context for a task and increment its pin_count so it
233	* can't get swapped to another task. This also increments its
234	* reference count so that the context can't get freed.
235	*/
236	static struct perf_event_context *
237	perf_pin_task_context(struct task_struct *task, int ctxn)
238	{
239	struct perf_event_context *ctx;
240	unsigned long flags;
241
242	ctx = perf_lock_task_context(task, ctxn, &flags);
243	if (ctx) {
244	++ctx->pin_count;
245	raw_spin_unlock_irqrestore(&ctx->lock, flags);
246	}
247	return ctx;
248	}
249
250	static void perf_unpin_context(struct perf_event_context *ctx)
251	{
252	unsigned long flags;
253
254	raw_spin_lock_irqsave(&ctx->lock, flags);
255	--ctx->pin_count;
256	raw_spin_unlock_irqrestore(&ctx->lock, flags);
257	put_ctx(ctx);
258	}
259
260	/*
261	* Update the record of the current time in a context.
262	*/
263	static void update_context_time(struct perf_event_context *ctx)
264	{
265	u64 now = perf_clock();
266
267	ctx->time += now - ctx->timestamp;
268	ctx->timestamp = now;
269	}
270
271	static u64 perf_event_time(struct perf_event *event)
272	{
273	struct perf_event_context *ctx = event->ctx;
274	return ctx ? ctx->time : 0;
275	}
276
277	/*
278	* Update the total_time_enabled and total_time_running fields for a event.
279	*/
280	static void update_event_times(struct perf_event *event)
281	{
282	struct perf_event_context *ctx = event->ctx;
283	u64 run_end;
284
285	if (event->state < PERF_EVENT_STATE_INACTIVE \|\|
286	event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
287	return;
288
289	if (ctx->is_active)
290	run_end = perf_event_time(event);
291	else
292	run_end = event->tstamp_stopped;
293
294	event->total_time_enabled = run_end - event->tstamp_enabled;
295
296	if (event->state == PERF_EVENT_STATE_INACTIVE)
297	run_end = event->tstamp_stopped;
298	else
299	run_end = perf_event_time(event);
300
301	event->total_time_running = run_end - event->tstamp_running;
302	}
303
304	/*
305	* Update total_time_enabled and total_time_running for all events in a group.
306	*/
307	static void update_group_times(struct perf_event *leader)
308	{
309	struct perf_event *event;
310
311	update_event_times(leader);
312	list_for_each_entry(event, &leader->sibling_list, group_entry)
313	update_event_times(event);
314	}
315
316	static struct list_head *
317	ctx_group_list(struct perf_event event, struct perf_event_context ctx)
318	{
319	if (event->attr.pinned)
320	return &ctx->pinned_groups;
321	else
322	return &ctx->flexible_groups;
323	}
324
325	/*
326	* Add a event from the lists for its context.
327	* Must be called with ctx->mutex and ctx->lock held.
328	*/
329	static void
330	list_add_event(struct perf_event event, struct perf_event_context ctx)
331	{
332	WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
333	event->attach_state \|= PERF_ATTACH_CONTEXT;
334
335	/*
336	* If we're a stand alone event or group leader, we go to the context
337	* list, group events are kept attached to the group so that
338	* perf_group_detach can, at all times, locate all siblings.
339	*/
340	if (event->group_leader == event) {
341	struct list_head *list;
342
343	if (is_software_event(event))
344	event->group_flags \|= PERF_GROUP_SOFTWARE;
345
346	list = ctx_group_list(event, ctx);
347	list_add_tail(&event->group_entry, list);
348	}
349
350	list_add_rcu(&event->event_entry, &ctx->event_list);
351	if (!ctx->nr_events)
352	perf_pmu_rotate_start(ctx->pmu);
353	ctx->nr_events++;
354	if (event->attr.inherit_stat)
355	ctx->nr_stat++;
356	}
357
358	/*
359	* Called at perf_event creation and when events are attached/detached from a
360	* group.
361	*/
362	static void perf_event__read_size(struct perf_event *event)
363	{
364	int entry = sizeof(u64); /* value */
365	int size = 0;
366	int nr = 1;
367
368	if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
369	size += sizeof(u64);
370
371	if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
372	size += sizeof(u64);
373
374	if (event->attr.read_format & PERF_FORMAT_ID)
375	entry += sizeof(u64);
376
377	if (event->attr.read_format & PERF_FORMAT_GROUP) {
378	nr += event->group_leader->nr_siblings;
379	size += sizeof(u64);
380	}
381
382	size += entry * nr;
383	event->read_size = size;
384	}
385
386	static void perf_event__header_size(struct perf_event *event)
387	{
388	struct perf_sample_data *data;
389	u64 sample_type = event->attr.sample_type;
390	u16 size = 0;
391
392	perf_event__read_size(event);
393
394	if (sample_type & PERF_SAMPLE_IP)
395	size += sizeof(data->ip);
396
397	if (sample_type & PERF_SAMPLE_ADDR)
398	size += sizeof(data->addr);
399
400	if (sample_type & PERF_SAMPLE_PERIOD)
401	size += sizeof(data->period);
402
403	if (sample_type & PERF_SAMPLE_READ)
404	size += event->read_size;
405
406	event->header_size = size;
407	}
408
409	static void perf_event__id_header_size(struct perf_event *event)
410	{
411	struct perf_sample_data *data;
412	u64 sample_type = event->attr.sample_type;
413	u16 size = 0;
414
415	if (sample_type & PERF_SAMPLE_TID)
416	size += sizeof(data->tid_entry);
417
418	if (sample_type & PERF_SAMPLE_TIME)
419	size += sizeof(data->time);
420
421	if (sample_type & PERF_SAMPLE_ID)
422	size += sizeof(data->id);
423
424	if (sample_type & PERF_SAMPLE_STREAM_ID)
425	size += sizeof(data->stream_id);
426
427	if (sample_type & PERF_SAMPLE_CPU)
428	size += sizeof(data->cpu_entry);
429
430	event->id_header_size = size;
431	}
432
433	static void perf_group_attach(struct perf_event *event)
434	{
435	struct perf_event group_leader = event->group_leader, pos;
436
437	/*
438	* We can have double attach due to group movement in perf_event_open.
439	*/
440	if (event->attach_state & PERF_ATTACH_GROUP)
441	return;
442
443	event->attach_state \|= PERF_ATTACH_GROUP;
444
445	if (group_leader == event)
446	return;
447
448	if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
449	!is_software_event(event))
450	group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
451
452	list_add_tail(&event->group_entry, &group_leader->sibling_list);
453	group_leader->nr_siblings++;
454
455	perf_event__header_size(group_leader);
456
457	list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
458	perf_event__header_size(pos);
459	}
460
461	/*
462	* Remove a event from the lists for its context.
463	* Must be called with ctx->mutex and ctx->lock held.
464	*/
465	static void
466	list_del_event(struct perf_event event, struct perf_event_context ctx)
467	{
468	/*
469	* We can have double detach due to exit/hot-unplug + close.
470	*/
471	if (!(event->attach_state & PERF_ATTACH_CONTEXT))
472	return;
473
474	event->attach_state &= ~PERF_ATTACH_CONTEXT;
475
476	ctx->nr_events--;
477	if (event->attr.inherit_stat)
478	ctx->nr_stat--;
479
480	list_del_rcu(&event->event_entry);
481
482	if (event->group_leader == event)
483	list_del_init(&event->group_entry);
484
485	update_group_times(event);
486
487	/*
488	* If event was in error state, then keep it
489	* that way, otherwise bogus counts will be
490	* returned on read(). The only way to get out
491	* of error state is by explicit re-enabling
492	* of the event
493	*/
494	if (event->state > PERF_EVENT_STATE_OFF)
495	event->state = PERF_EVENT_STATE_OFF;
496	}
497
498	static void perf_group_detach(struct perf_event *event)
499	{
500	struct perf_event sibling, tmp;
501	struct list_head *list = NULL;
502
503	/*
504	* We can have double detach due to exit/hot-unplug + close.
505	*/
506	if (!(event->attach_state & PERF_ATTACH_GROUP))
507	return;
508
509	event->attach_state &= ~PERF_ATTACH_GROUP;
510
511	/*
512	* If this is a sibling, remove it from its group.
513	*/
514	if (event->group_leader != event) {
515	list_del_init(&event->group_entry);
516	event->group_leader->nr_siblings--;
517	goto out;
518	}
519
520	if (!list_empty(&event->group_entry))
521	list = &event->group_entry;
522
523	/*
524	* If this was a group event with sibling events then
525	* upgrade the siblings to singleton events by adding them
526	* to whatever list we are on.
527	*/
528	list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
529	if (list)
530	list_move_tail(&sibling->group_entry, list);
531	sibling->group_leader = sibling;
532
533	/* Inherit group flags from the previous leader */
534	sibling->group_flags = event->group_flags;
535	}
536
537	out:
538	perf_event__header_size(event->group_leader);
539
540	list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
541	perf_event__header_size(tmp);
542	}
543
544	static inline int
545	event_filter_match(struct perf_event *event)
546	{
547	return event->cpu == -1 \|\| event->cpu == smp_processor_id();
548	}
549
550	static void
551	event_sched_out(struct perf_event *event,
552	struct perf_cpu_context *cpuctx,
553	struct perf_event_context *ctx)
554	{
555	u64 tstamp = perf_event_time(event);
556	u64 delta;
557	/*
558	* An event which could not be activated because of
559	* filter mismatch still needs to have its timings
560	* maintained, otherwise bogus information is return
561	* via read() for time_enabled, time_running:
562	*/
563	if (event->state == PERF_EVENT_STATE_INACTIVE
564	&& !event_filter_match(event)) {
565	delta = ctx->time - event->tstamp_stopped;
566	event->tstamp_running += delta;
567	event->tstamp_stopped = tstamp;
568	}
569
570	if (event->state != PERF_EVENT_STATE_ACTIVE)
571	return;
572
573	event->state = PERF_EVENT_STATE_INACTIVE;
574	if (event->pending_disable) {
575	event->pending_disable = 0;
576	event->state = PERF_EVENT_STATE_OFF;
577	}
578	event->tstamp_stopped = tstamp;
579	event->pmu->del(event, 0);
580	event->oncpu = -1;
581
582	if (!is_software_event(event))
583	cpuctx->active_oncpu--;
584	ctx->nr_active--;
585	if (event->attr.exclusive \|\| !cpuctx->active_oncpu)
586	cpuctx->exclusive = 0;
587	}
588
589	static void
590	group_sched_out(struct perf_event *group_event,
591	struct perf_cpu_context *cpuctx,
592	struct perf_event_context *ctx)
593	{
594	struct perf_event *event;
595	int state = group_event->state;
596
597	event_sched_out(group_event, cpuctx, ctx);
598
599	/*
600	* Schedule out siblings (if any):
601	*/
602	list_for_each_entry(event, &group_event->sibling_list, group_entry)
603	event_sched_out(event, cpuctx, ctx);
604
605	if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
606	cpuctx->exclusive = 0;
607	}
608
609	static inline struct perf_cpu_context *
610	__get_cpu_context(struct perf_event_context *ctx)
611	{
612	return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
613	}
614
615	/*
616	* Cross CPU call to remove a performance event
617	*
618	* We disable the event on the hardware level first. After that we
619	* remove it from the context list.
620	*/
621	static void __perf_event_remove_from_context(void *info)
622	{
623	struct perf_event *event = info;
624	struct perf_event_context *ctx = event->ctx;
625	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
626
627	/*
628	* If this is a task context, we need to check whether it is
629	* the current task context of this cpu. If not it has been
630	* scheduled out before the smp call arrived.
631	*/
632	if (ctx->task && cpuctx->task_ctx != ctx)
633	return;
634
635	raw_spin_lock(&ctx->lock);
636
637	event_sched_out(event, cpuctx, ctx);
638
639	list_del_event(event, ctx);
640
641	raw_spin_unlock(&ctx->lock);
642	}
643
644
645	/*
646	* Remove the event from a task's (or a CPU's) list of events.
647	*
648	* Must be called with ctx->mutex held.
649	*
650	* CPU events are removed with a smp call. For task events we only
651	* call when the task is on a CPU.
652	*
653	* If event->ctx is a cloned context, callers must make sure that
654	* every task struct that event->ctx->task could possibly point to
655	* remains valid. This is OK when called from perf_release since
656	* that only calls us on the top-level context, which can't be a clone.
657	* When called from perf_event_exit_task, it's OK because the
658	* context has been detached from its task.
659	*/
660	static void perf_event_remove_from_context(struct perf_event *event)
661	{
662	struct perf_event_context *ctx = event->ctx;
663	struct task_struct *task = ctx->task;
664
665	if (!task) {
666	/*
667	* Per cpu events are removed via an smp call and
668	* the removal is always successful.
669	*/
670	smp_call_function_single(event->cpu,
671	__perf_event_remove_from_context,
672	event, 1);
673	return;
674	}
675
676	retry:
677	task_oncpu_function_call(task, __perf_event_remove_from_context,
678	event);
679
680	raw_spin_lock_irq(&ctx->lock);
681	/*
682	* If the context is active we need to retry the smp call.
683	*/
684	if (ctx->nr_active && !list_empty(&event->group_entry)) {
685	raw_spin_unlock_irq(&ctx->lock);
686	goto retry;
687	}
688
689	/*
690	* The lock prevents that this context is scheduled in so we
691	* can remove the event safely, if the call above did not
692	* succeed.
693	*/
694	if (!list_empty(&event->group_entry))
695	list_del_event(event, ctx);
696	raw_spin_unlock_irq(&ctx->lock);
697	}
698
699	/*
700	* Cross CPU call to disable a performance event
701	*/
702	static void __perf_event_disable(void *info)
703	{
704	struct perf_event *event = info;
705	struct perf_event_context *ctx = event->ctx;
706	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
707
708	/*
709	* If this is a per-task event, need to check whether this
710	* event's task is the current task on this cpu.
711	*/
712	if (ctx->task && cpuctx->task_ctx != ctx)
713	return;
714
715	raw_spin_lock(&ctx->lock);
716
717	/*
718	* If the event is on, turn it off.
719	* If it is in error state, leave it in error state.
720	*/
721	if (event->state >= PERF_EVENT_STATE_INACTIVE) {
722	update_context_time(ctx);
723	update_group_times(event);
724	if (event == event->group_leader)
725	group_sched_out(event, cpuctx, ctx);
726	else
727	event_sched_out(event, cpuctx, ctx);
728	event->state = PERF_EVENT_STATE_OFF;
729	}
730
731	raw_spin_unlock(&ctx->lock);
732	}
733
734	/*
735	* Disable a event.
736	*
737	* If event->ctx is a cloned context, callers must make sure that
738	* every task struct that event->ctx->task could possibly point to
739	* remains valid. This condition is satisifed when called through
740	* perf_event_for_each_child or perf_event_for_each because they
741	* hold the top-level event's child_mutex, so any descendant that
742	* goes to exit will block in sync_child_event.
743	* When called from perf_pending_event it's OK because event->ctx
744	* is the current context on this CPU and preemption is disabled,
745	* hence we can't get into perf_event_task_sched_out for this context.
746	*/
747	void perf_event_disable(struct perf_event *event)
748	{
749	struct perf_event_context *ctx = event->ctx;
750	struct task_struct *task = ctx->task;
751
752	if (!task) {
753	/*
754	* Disable the event on the cpu that it's on
755	*/
756	smp_call_function_single(event->cpu, __perf_event_disable,
757	event, 1);
758	return;
759	}
760
761	retry:
762	task_oncpu_function_call(task, __perf_event_disable, event);
763
764	raw_spin_lock_irq(&ctx->lock);
765	/*
766	* If the event is still active, we need to retry the cross-call.
767	*/
768	if (event->state == PERF_EVENT_STATE_ACTIVE) {
769	raw_spin_unlock_irq(&ctx->lock);
770	goto retry;
771	}
772
773	/*
774	* Since we have the lock this context can't be scheduled
775	* in, so we can change the state safely.
776	*/
777	if (event->state == PERF_EVENT_STATE_INACTIVE) {
778	update_group_times(event);
779	event->state = PERF_EVENT_STATE_OFF;
780	}
781
782	raw_spin_unlock_irq(&ctx->lock);
783	}
784
785	#define MAX_INTERRUPTS (~0ULL)
786
787	static void perf_log_throttle(struct perf_event *event, int enable);
788
789	static int
790	event_sched_in(struct perf_event *event,
791	struct perf_cpu_context *cpuctx,
792	struct perf_event_context *ctx)
793	{
794	u64 tstamp = perf_event_time(event);
795
796	if (event->state <= PERF_EVENT_STATE_OFF)
797	return 0;
798
799	event->state = PERF_EVENT_STATE_ACTIVE;
800	event->oncpu = smp_processor_id();
801
802	/*
803	* Unthrottle events, since we scheduled we might have missed several
804	* ticks already, also for a heavily scheduling task there is little
805	* guarantee it'll get a tick in a timely manner.
806	*/
807	if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
808	perf_log_throttle(event, 1);
809	event->hw.interrupts = 0;
810	}
811
812	/*
813	* The new state must be visible before we turn it on in the hardware:
814	*/
815	smp_wmb();
816
817	if (event->pmu->add(event, PERF_EF_START)) {
818	event->state = PERF_EVENT_STATE_INACTIVE;
819	event->oncpu = -1;
820	return -EAGAIN;
821	}
822
823	event->tstamp_running += tstamp - event->tstamp_stopped;
824
825	event->shadow_ctx_time = tstamp - ctx->timestamp;
826
827	if (!is_software_event(event))
828	cpuctx->active_oncpu++;
829	ctx->nr_active++;
830
831	if (event->attr.exclusive)
832	cpuctx->exclusive = 1;
833
834	return 0;
835	}
836
837	static int
838	group_sched_in(struct perf_event *group_event,
839	struct perf_cpu_context *cpuctx,
840	struct perf_event_context *ctx)
841	{
842	struct perf_event event, partial_group = NULL;
843	struct pmu *pmu = group_event->pmu;
844	u64 now = ctx->time;
845	bool simulate = false;
846
847	if (group_event->state == PERF_EVENT_STATE_OFF)
848	return 0;
849
850	pmu->start_txn(pmu);
851
852	if (event_sched_in(group_event, cpuctx, ctx)) {
853	pmu->cancel_txn(pmu);
854	return -EAGAIN;
855	}
856
857	/*
858	* Schedule in siblings as one group (if any):
859	*/
860	list_for_each_entry(event, &group_event->sibling_list, group_entry) {
861	if (event_sched_in(event, cpuctx, ctx)) {
862	partial_group = event;
863	goto group_error;
864	}
865	}
866
867	if (!pmu->commit_txn(pmu))
868	return 0;
869
870	group_error:
871	/*
872	* Groups can be scheduled in as one unit only, so undo any
873	* partial group before returning:
874	* The events up to the failed event are scheduled out normally,
875	* tstamp_stopped will be updated.
876	*
877	* The failed events and the remaining siblings need to have
878	* their timings updated as if they had gone thru event_sched_in()
879	* and event_sched_out(). This is required to get consistent timings
880	* across the group. This also takes care of the case where the group
881	* could never be scheduled by ensuring tstamp_stopped is set to mark
882	* the time the event was actually stopped, such that time delta
883	* calculation in update_event_times() is correct.
884	*/
885	list_for_each_entry(event, &group_event->sibling_list, group_entry) {
886	if (event == partial_group)
887	simulate = true;
888
889	if (simulate) {
890	event->tstamp_running += now - event->tstamp_stopped;
891	event->tstamp_stopped = now;
892	} else {
893	event_sched_out(event, cpuctx, ctx);
894	}
895	}
896	event_sched_out(group_event, cpuctx, ctx);
897
898	pmu->cancel_txn(pmu);
899
900	return -EAGAIN;
901	}
902
903	/*
904	* Work out whether we can put this event group on the CPU now.
905	*/
906	static int group_can_go_on(struct perf_event *event,
907	struct perf_cpu_context *cpuctx,
908	int can_add_hw)
909	{
910	/*
911	* Groups consisting entirely of software events can always go on.
912	*/
913	if (event->group_flags & PERF_GROUP_SOFTWARE)
914	return 1;
915	/*
916	* If an exclusive group is already on, no other hardware
917	* events can go on.
918	*/
919	if (cpuctx->exclusive)
920	return 0;
921	/*
922	* If this group is exclusive and there are already
923	* events on the CPU, it can't go on.
924	*/
925	if (event->attr.exclusive && cpuctx->active_oncpu)
926	return 0;
927	/*
928	* Otherwise, try to add it if all previous groups were able
929	* to go on.
930	*/
931	return can_add_hw;
932	}
933
934	static void add_event_to_ctx(struct perf_event *event,
935	struct perf_event_context *ctx)
936	{
937	u64 tstamp = perf_event_time(event);
938
939	list_add_event(event, ctx);
940	perf_group_attach(event);
941	event->tstamp_enabled = tstamp;
942	event->tstamp_running = tstamp;
943	event->tstamp_stopped = tstamp;
944	}
945
946	/*
947	* Cross CPU call to install and enable a performance event
948	*
949	* Must be called with ctx->mutex held
950	*/
951	static void __perf_install_in_context(void *info)
952	{
953	struct perf_event *event = info;
954	struct perf_event_context *ctx = event->ctx;
955	struct perf_event *leader = event->group_leader;
956	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
957	int err;
958
959	/*
960	* If this is a task context, we need to check whether it is
961	* the current task context of this cpu. If not it has been
962	* scheduled out before the smp call arrived.
963	* Or possibly this is the right context but it isn't
964	* on this cpu because it had no events.
965	*/
966	if (ctx->task && cpuctx->task_ctx != ctx) {
967	if (cpuctx->task_ctx \|\| ctx->task != current)
968	return;
969	cpuctx->task_ctx = ctx;
970	}
971
972	raw_spin_lock(&ctx->lock);
973	ctx->is_active = 1;
974	update_context_time(ctx);
975
976	add_event_to_ctx(event, ctx);
977
978	if (!event_filter_match(event))
979	goto unlock;
980
981	/*
982	* Don't put the event on if it is disabled or if
983	* it is in a group and the group isn't on.
984	*/
985	if (event->state != PERF_EVENT_STATE_INACTIVE \|\|
986	(leader != event && leader->state != PERF_EVENT_STATE_ACTIVE))
987	goto unlock;
988
989	/*
990	* An exclusive event can't go on if there are already active
991	* hardware events, and no hardware event can go on if there
992	* is already an exclusive event on.
993	*/
994	if (!group_can_go_on(event, cpuctx, 1))
995	err = -EEXIST;
996	else
997	err = event_sched_in(event, cpuctx, ctx);
998
999	if (err) {
1000	/*
1001	* This event couldn't go on. If it is in a group
1002	* then we have to pull the whole group off.
1003	* If the event group is pinned then put it in error state.
1004	*/
1005	if (leader != event)
1006	group_sched_out(leader, cpuctx, ctx);
1007	if (leader->attr.pinned) {
1008	update_group_times(leader);
1009	leader->state = PERF_EVENT_STATE_ERROR;
1010	}
1011	}
1012
1013	unlock:
1014	raw_spin_unlock(&ctx->lock);
1015	}
1016
1017	/*
1018	* Attach a performance event to a context
1019	*
1020	* First we add the event to the list with the hardware enable bit
1021	* in event->hw_config cleared.
1022	*
1023	* If the event is attached to a task which is on a CPU we use a smp
1024	* call to enable it in the task context. The task might have been
1025	* scheduled away, but we check this in the smp call again.
1026	*
1027	* Must be called with ctx->mutex held.
1028	*/
1029	static void
1030	perf_install_in_context(struct perf_event_context *ctx,
1031	struct perf_event *event,
1032	int cpu)
1033	{
1034	struct task_struct *task = ctx->task;
1035
1036	event->ctx = ctx;
1037
1038	if (!task) {
1039	/*
1040	* Per cpu events are installed via an smp call and
1041	* the install is always successful.
1042	*/
1043	smp_call_function_single(cpu, __perf_install_in_context,
1044	event, 1);
1045	return;
1046	}
1047
1048	retry:
1049	task_oncpu_function_call(task, __perf_install_in_context,
1050	event);
1051
1052	raw_spin_lock_irq(&ctx->lock);
1053	/*
1054	* we need to retry the smp call.
1055	*/
1056	if (ctx->is_active && list_empty(&event->group_entry)) {
1057	raw_spin_unlock_irq(&ctx->lock);
1058	goto retry;
1059	}
1060
1061	/*
1062	* The lock prevents that this context is scheduled in so we
1063	* can add the event safely, if it the call above did not
1064	* succeed.
1065	*/
1066	if (list_empty(&event->group_entry))
1067	add_event_to_ctx(event, ctx);
1068	raw_spin_unlock_irq(&ctx->lock);
1069	}
1070
1071	/*
1072	* Put a event into inactive state and update time fields.
1073	* Enabling the leader of a group effectively enables all
1074	* the group members that aren't explicitly disabled, so we
1075	* have to update their ->tstamp_enabled also.
1076	* Note: this works for group members as well as group leaders
1077	* since the non-leader members' sibling_lists will be empty.
1078	*/
1079	static void __perf_event_mark_enabled(struct perf_event *event,
1080	struct perf_event_context *ctx)
1081	{
1082	struct perf_event *sub;
1083	u64 tstamp = perf_event_time(event);
1084
1085	event->state = PERF_EVENT_STATE_INACTIVE;
1086	event->tstamp_enabled = tstamp - event->total_time_enabled;
1087	list_for_each_entry(sub, &event->sibling_list, group_entry) {
1088	if (sub->state >= PERF_EVENT_STATE_INACTIVE)
1089	sub->tstamp_enabled = tstamp - sub->total_time_enabled;
1090	}
1091	}
1092
1093	/*
1094	* Cross CPU call to enable a performance event
1095	*/
1096	static void __perf_event_enable(void *info)
1097	{
1098	struct perf_event *event = info;
1099	struct perf_event_context *ctx = event->ctx;
1100	struct perf_event *leader = event->group_leader;
1101	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1102	int err;
1103
1104	/*
1105	* If this is a per-task event, need to check whether this
1106	* event's task is the current task on this cpu.
1107	*/
1108	if (ctx->task && cpuctx->task_ctx != ctx) {
1109	if (cpuctx->task_ctx \|\| ctx->task != current)
1110	return;
1111	cpuctx->task_ctx = ctx;
1112	}
1113
1114	raw_spin_lock(&ctx->lock);
1115	ctx->is_active = 1;
1116	update_context_time(ctx);
1117
1118	if (event->state >= PERF_EVENT_STATE_INACTIVE)
1119	goto unlock;
1120	__perf_event_mark_enabled(event, ctx);
1121
1122	if (!event_filter_match(event))
1123	goto unlock;
1124
1125	/*
1126	* If the event is in a group and isn't the group leader,
1127	* then don't put it on unless the group is on.
1128	*/
1129	if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
1130	goto unlock;
1131
1132	if (!group_can_go_on(event, cpuctx, 1)) {
1133	err = -EEXIST;
1134	} else {
1135	if (event == leader)
1136	err = group_sched_in(event, cpuctx, ctx);
1137	else
1138	err = event_sched_in(event, cpuctx, ctx);
1139	}
1140
1141	if (err) {
1142	/*
1143	* If this event can't go on and it's part of a
1144	* group, then the whole group has to come off.
1145	*/
1146	if (leader != event)
1147	group_sched_out(leader, cpuctx, ctx);
1148	if (leader->attr.pinned) {
1149	update_group_times(leader);
1150	leader->state = PERF_EVENT_STATE_ERROR;
1151	}
1152	}
1153
1154	unlock:
1155	raw_spin_unlock(&ctx->lock);
1156	}
1157
1158	/*
1159	* Enable a event.
1160	*
1161	* If event->ctx is a cloned context, callers must make sure that
1162	* every task struct that event->ctx->task could possibly point to
1163	* remains valid. This condition is satisfied when called through
1164	* perf_event_for_each_child or perf_event_for_each as described
1165	* for perf_event_disable.
1166	*/
1167	void perf_event_enable(struct perf_event *event)
1168	{
1169	struct perf_event_context *ctx = event->ctx;
1170	struct task_struct *task = ctx->task;
1171
1172	if (!task) {
1173	/*
1174	* Enable the event on the cpu that it's on
1175	*/
1176	smp_call_function_single(event->cpu, __perf_event_enable,
1177	event, 1);
1178	return;
1179	}
1180
1181	raw_spin_lock_irq(&ctx->lock);
1182	if (event->state >= PERF_EVENT_STATE_INACTIVE)
1183	goto out;
1184
1185	/*
1186	* If the event is in error state, clear that first.
1187	* That way, if we see the event in error state below, we
1188	* know that it has gone back into error state, as distinct
1189	* from the task having been scheduled away before the
1190	* cross-call arrived.
1191	*/
1192	if (event->state == PERF_EVENT_STATE_ERROR)
1193	event->state = PERF_EVENT_STATE_OFF;
1194
1195	retry:
1196	raw_spin_unlock_irq(&ctx->lock);
1197	task_oncpu_function_call(task, __perf_event_enable, event);
1198
1199	raw_spin_lock_irq(&ctx->lock);
1200
1201	/*
1202	* If the context is active and the event is still off,
1203	* we need to retry the cross-call.
1204	*/
1205	if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF)
1206	goto retry;
1207
1208	/*
1209	* Since we have the lock this context can't be scheduled
1210	* in, so we can change the state safely.
1211	*/
1212	if (event->state == PERF_EVENT_STATE_OFF)
1213	__perf_event_mark_enabled(event, ctx);
1214
1215	out:
1216	raw_spin_unlock_irq(&ctx->lock);
1217	}
1218
1219	static int perf_event_refresh(struct perf_event *event, int refresh)
1220	{
1221	/*
1222	* not supported on inherited events
1223	*/
1224	if (event->attr.inherit \|\| !is_sampling_event(event))
1225	return -EINVAL;
1226
1227	atomic_add(refresh, &event->event_limit);
1228	perf_event_enable(event);
1229
1230	return 0;
1231	}
1232
1233	static void ctx_sched_out(struct perf_event_context *ctx,
1234	struct perf_cpu_context *cpuctx,
1235	enum event_type_t event_type)
1236	{
1237	struct perf_event *event;
1238
1239	raw_spin_lock(&ctx->lock);
1240	perf_pmu_disable(ctx->pmu);
1241	ctx->is_active = 0;
1242	if (likely(!ctx->nr_events))
1243	goto out;
1244	update_context_time(ctx);
1245
1246	if (!ctx->nr_active)
1247	goto out;
1248
1249	if (event_type & EVENT_PINNED) {
1250	list_for_each_entry(event, &ctx->pinned_groups, group_entry)
1251	group_sched_out(event, cpuctx, ctx);
1252	}
1253
1254	if (event_type & EVENT_FLEXIBLE) {
1255	list_for_each_entry(event, &ctx->flexible_groups, group_entry)
1256	group_sched_out(event, cpuctx, ctx);
1257	}
1258	out:
1259	perf_pmu_enable(ctx->pmu);
1260	raw_spin_unlock(&ctx->lock);
1261	}
1262
1263	/*
1264	* Test whether two contexts are equivalent, i.e. whether they
1265	* have both been cloned from the same version of the same context
1266	* and they both have the same number of enabled events.
1267	* If the number of enabled events is the same, then the set
1268	* of enabled events should be the same, because these are both
1269	* inherited contexts, therefore we can't access individual events
1270	* in them directly with an fd; we can only enable/disable all
1271	* events via prctl, or enable/disable all events in a family
1272	* via ioctl, which will have the same effect on both contexts.
1273	*/
1274	static int context_equiv(struct perf_event_context *ctx1,
1275	struct perf_event_context *ctx2)
1276	{
1277	return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
1278	&& ctx1->parent_gen == ctx2->parent_gen
1279	&& !ctx1->pin_count && !ctx2->pin_count;
1280	}
1281
1282	static void __perf_event_sync_stat(struct perf_event *event,
1283	struct perf_event *next_event)
1284	{
1285	u64 value;
1286
1287	if (!event->attr.inherit_stat)
1288	return;
1289
1290	/*
1291	* Update the event value, we cannot use perf_event_read()
1292	* because we're in the middle of a context switch and have IRQs
1293	* disabled, which upsets smp_call_function_single(), however
1294	* we know the event must be on the current CPU, therefore we
1295	* don't need to use it.
1296	*/
1297	switch (event->state) {
1298	case PERF_EVENT_STATE_ACTIVE:
1299	event->pmu->read(event);
1300	/* fall-through */
1301
1302	case PERF_EVENT_STATE_INACTIVE:
1303	update_event_times(event);
1304	break;
1305
1306	default:
1307	break;
1308	}
1309
1310	/*
1311	* In order to keep per-task stats reliable we need to flip the event
1312	* values when we flip the contexts.
1313	*/
1314	value = local64_read(&next_event->count);
1315	value = local64_xchg(&event->count, value);
1316	local64_set(&next_event->count, value);
1317
1318	swap(event->total_time_enabled, next_event->total_time_enabled);
1319	swap(event->total_time_running, next_event->total_time_running);
1320
1321	/*
1322	* Since we swizzled the values, update the user visible data too.
1323	*/
1324	perf_event_update_userpage(event);
1325	perf_event_update_userpage(next_event);
1326	}
1327
1328	#define list_next_entry(pos, member) \
1329	list_entry(pos->member.next, typeof(*pos), member)
1330
1331	static void perf_event_sync_stat(struct perf_event_context *ctx,
1332	struct perf_event_context *next_ctx)
1333	{
1334	struct perf_event event, next_event;
1335
1336	if (!ctx->nr_stat)
1337	return;
1338
1339	update_context_time(ctx);
1340
1341	event = list_first_entry(&ctx->event_list,
1342	struct perf_event, event_entry);
1343
1344	next_event = list_first_entry(&next_ctx->event_list,
1345	struct perf_event, event_entry);
1346
1347	while (&event->event_entry != &ctx->event_list &&
1348	&next_event->event_entry != &next_ctx->event_list) {
1349
1350	__perf_event_sync_stat(event, next_event);
1351
1352	event = list_next_entry(event, event_entry);
1353	next_event = list_next_entry(next_event, event_entry);
1354	}
1355	}
1356
1357	void perf_event_context_sched_out(struct task_struct *task, int ctxn,
1358	struct task_struct *next)
1359	{
1360	struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
1361	struct perf_event_context *next_ctx;
1362	struct perf_event_context *parent;
1363	struct perf_cpu_context *cpuctx;
1364	int do_switch = 1;
1365
1366	if (likely(!ctx))
1367	return;
1368
1369	cpuctx = __get_cpu_context(ctx);
1370	if (!cpuctx->task_ctx)
1371	return;
1372
1373	rcu_read_lock();
1374	parent = rcu_dereference(ctx->parent_ctx);
1375	next_ctx = next->perf_event_ctxp[ctxn];
1376	if (parent && next_ctx &&
1377	rcu_dereference(next_ctx->parent_ctx) == parent) {
1378	/*
1379	* Looks like the two contexts are clones, so we might be
1380	* able to optimize the context switch. We lock both
1381	* contexts and check that they are clones under the
1382	* lock (including re-checking that neither has been
1383	* uncloned in the meantime). It doesn't matter which
1384	* order we take the locks because no other cpu could
1385	* be trying to lock both of these tasks.
1386	*/
1387	raw_spin_lock(&ctx->lock);
1388	raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
1389	if (context_equiv(ctx, next_ctx)) {
1390	/*
1391	* XXX do we need a memory barrier of sorts
1392	* wrt to rcu_dereference() of perf_event_ctxp
1393	*/
1394	task->perf_event_ctxp[ctxn] = next_ctx;
1395	next->perf_event_ctxp[ctxn] = ctx;
1396	ctx->task = next;
1397	next_ctx->task = task;
1398	do_switch = 0;
1399
1400	perf_event_sync_stat(ctx, next_ctx);
1401	}
1402	raw_spin_unlock(&next_ctx->lock);
1403	raw_spin_unlock(&ctx->lock);
1404	}
1405	rcu_read_unlock();
1406
1407	if (do_switch) {
1408	ctx_sched_out(ctx, cpuctx, EVENT_ALL);
1409	cpuctx->task_ctx = NULL;
1410	}
1411	}
1412
1413	#define for_each_task_context_nr(ctxn) \
1414	for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
1415
1416	/*
1417	* Called from scheduler to remove the events of the current task,
1418	* with interrupts disabled.
1419	*
1420	* We stop each event and update the event value in event->count.
1421	*
1422	* This does not protect us against NMI, but disable()
1423	* sets the disabled bit in the control field of event _before_
1424	* accessing the event control register. If a NMI hits, then it will
1425	* not restart the event.
1426	*/
1427	void __perf_event_task_sched_out(struct task_struct *task,
1428	struct task_struct *next)
1429	{
1430	int ctxn;
1431
1432	for_each_task_context_nr(ctxn)
1433	perf_event_context_sched_out(task, ctxn, next);
1434	}
1435
1436	static void task_ctx_sched_out(struct perf_event_context *ctx,
1437	enum event_type_t event_type)
1438	{
1439	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1440
1441	if (!cpuctx->task_ctx)
1442	return;
1443
1444	if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
1445	return;
1446
1447	ctx_sched_out(ctx, cpuctx, event_type);
1448	cpuctx->task_ctx = NULL;
1449	}
1450
1451	/*
1452	* Called with IRQs disabled
1453	*/
1454	static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
1455	enum event_type_t event_type)
1456	{
1457	ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
1458	}
1459
1460	static void
1461	ctx_pinned_sched_in(struct perf_event_context *ctx,
1462	struct perf_cpu_context *cpuctx)
1463	{
1464	struct perf_event *event;
1465
1466	list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
1467	if (event->state <= PERF_EVENT_STATE_OFF)
1468	continue;
1469	if (!event_filter_match(event))
1470	continue;
1471
1472	if (group_can_go_on(event, cpuctx, 1))
1473	group_sched_in(event, cpuctx, ctx);
1474
1475	/*
1476	* If this pinned group hasn't been scheduled,
1477	* put it in error state.
1478	*/
1479	if (event->state == PERF_EVENT_STATE_INACTIVE) {
1480	update_group_times(event);
1481	event->state = PERF_EVENT_STATE_ERROR;
1482	}
1483	}
1484	}
1485
1486	static void
1487	ctx_flexible_sched_in(struct perf_event_context *ctx,
1488	struct perf_cpu_context *cpuctx)
1489	{
1490	struct perf_event *event;
1491	int can_add_hw = 1;
1492
1493	list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
1494	/* Ignore events in OFF or ERROR state */
1495	if (event->state <= PERF_EVENT_STATE_OFF)
1496	continue;
1497	/*
1498	* Listen to the 'cpu' scheduling filter constraint
1499	* of events:
1500	*/
1501	if (!event_filter_match(event))
1502	continue;
1503
1504	if (group_can_go_on(event, cpuctx, can_add_hw)) {
1505	if (group_sched_in(event, cpuctx, ctx))
1506	can_add_hw = 0;
1507	}
1508	}
1509	}
1510
1511	static void
1512	ctx_sched_in(struct perf_event_context *ctx,
1513	struct perf_cpu_context *cpuctx,
1514	enum event_type_t event_type)
1515	{
1516	raw_spin_lock(&ctx->lock);
1517	ctx->is_active = 1;
1518	if (likely(!ctx->nr_events))
1519	goto out;
1520
1521	ctx->timestamp = perf_clock();
1522
1523	/*
1524	* First go through the list and put on any pinned groups
1525	* in order to give them the best chance of going on.
1526	*/
1527	if (event_type & EVENT_PINNED)
1528	ctx_pinned_sched_in(ctx, cpuctx);
1529
1530	/* Then walk through the lower prio flexible groups */
1531	if (event_type & EVENT_FLEXIBLE)
1532	ctx_flexible_sched_in(ctx, cpuctx);
1533
1534	out:
1535	raw_spin_unlock(&ctx->lock);
1536	}
1537
1538	static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
1539	enum event_type_t event_type)
1540	{
1541	struct perf_event_context *ctx = &cpuctx->ctx;
1542
1543	ctx_sched_in(ctx, cpuctx, event_type);
1544	}
1545
1546	static void task_ctx_sched_in(struct perf_event_context *ctx,
1547	enum event_type_t event_type)
1548	{
1549	struct perf_cpu_context *cpuctx;
1550
1551	cpuctx = __get_cpu_context(ctx);
1552	if (cpuctx->task_ctx == ctx)
1553	return;
1554
1555	ctx_sched_in(ctx, cpuctx, event_type);
1556	cpuctx->task_ctx = ctx;
1557	}
1558
1559	void perf_event_context_sched_in(struct perf_event_context *ctx)
1560	{
1561	struct perf_cpu_context *cpuctx;
1562
1563	cpuctx = __get_cpu_context(ctx);
1564	if (cpuctx->task_ctx == ctx)
1565	return;
1566
1567	perf_pmu_disable(ctx->pmu);
1568	/*
1569	* We want to keep the following priority order:
1570	* cpu pinned (that don't need to move), task pinned,
1571	* cpu flexible, task flexible.
1572	*/
1573	cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
1574
1575	ctx_sched_in(ctx, cpuctx, EVENT_PINNED);
1576	cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
1577	ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE);
1578
1579	cpuctx->task_ctx = ctx;
1580
1581	/*
1582	* Since these rotations are per-cpu, we need to ensure the
1583	* cpu-context we got scheduled on is actually rotating.
1584	*/
1585	perf_pmu_rotate_start(ctx->pmu);
1586	perf_pmu_enable(ctx->pmu);
1587	}
1588
1589	/*
1590	* Called from scheduler to add the events of the current task
1591	* with interrupts disabled.
1592	*
1593	* We restore the event value and then enable it.
1594	*
1595	* This does not protect us against NMI, but enable()
1596	* sets the enabled bit in the control field of event _before_
1597	* accessing the event control register. If a NMI hits, then it will
1598	* keep the event running.
1599	*/
1600	void __perf_event_task_sched_in(struct task_struct *task)
1601	{
1602	struct perf_event_context *ctx;
1603	int ctxn;
1604
1605	for_each_task_context_nr(ctxn) {
1606	ctx = task->perf_event_ctxp[ctxn];
1607	if (likely(!ctx))
1608	continue;
1609
1610	perf_event_context_sched_in(ctx);
1611	}
1612	}
1613
1614	static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
1615	{
1616	u64 frequency = event->attr.sample_freq;
1617	u64 sec = NSEC_PER_SEC;
1618	u64 divisor, dividend;
1619
1620	int count_fls, nsec_fls, frequency_fls, sec_fls;
1621
1622	count_fls = fls64(count);
1623	nsec_fls = fls64(nsec);
1624	frequency_fls = fls64(frequency);
1625	sec_fls = 30;
1626
1627	/*
1628	* We got @count in @nsec, with a target of sample_freq HZ
1629	* the target period becomes:
1630	*
1631	* @count * 10^9
1632	* period = -------------------
1633	* @nsec * sample_freq
1634	*
1635	*/
1636
1637	/*
1638	* Reduce accuracy by one bit such that @a and @b converge
1639	* to a similar magnitude.
1640	*/
1641	#define REDUCE_FLS(a, b) \
1642	do { \
1643	if (a##_fls > b##_fls) { \
1644	a >>= 1; \
1645	a##_fls--; \
1646	} else { \
1647	b >>= 1; \
1648	b##_fls--; \
1649	} \
1650	} while (0)
1651
1652	/*
1653	* Reduce accuracy until either term fits in a u64, then proceed with
1654	* the other, so that finally we can do a u64/u64 division.
1655	*/
1656	while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
1657	REDUCE_FLS(nsec, frequency);
1658	REDUCE_FLS(sec, count);
1659	}
1660
1661	if (count_fls + sec_fls > 64) {
1662	divisor = nsec * frequency;
1663
1664	while (count_fls + sec_fls > 64) {
1665	REDUCE_FLS(count, sec);
1666	divisor >>= 1;
1667	}
1668
1669	dividend = count * sec;
1670	} else {
1671	dividend = count * sec;
1672
1673	while (nsec_fls + frequency_fls > 64) {
1674	REDUCE_FLS(nsec, frequency);
1675	dividend >>= 1;
1676	}
1677
1678	divisor = nsec * frequency;
1679	}
1680
1681	if (!divisor)
1682	return dividend;
1683
1684	return div64_u64(dividend, divisor);
1685	}
1686
1687	static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
1688	{
1689	struct hw_perf_event *hwc = &event->hw;
1690	s64 period, sample_period;
1691	s64 delta;
1692
1693	period = perf_calculate_period(event, nsec, count);
1694
1695	delta = (s64)(period - hwc->sample_period);
1696	delta = (delta + 7) / 8; /* low pass filter */
1697
1698	sample_period = hwc->sample_period + delta;
1699
1700	if (!sample_period)
1701	sample_period = 1;
1702
1703	hwc->sample_period = sample_period;
1704
1705	if (local64_read(&hwc->period_left) > 8*sample_period) {
1706	event->pmu->stop(event, PERF_EF_UPDATE);
1707	local64_set(&hwc->period_left, 0);
1708	event->pmu->start(event, PERF_EF_RELOAD);
1709	}
1710	}
1711
1712	static void perf_ctx_adjust_freq(struct perf_event_context *ctx, u64 period)
1713	{
1714	struct perf_event *event;
1715	struct hw_perf_event *hwc;
1716	u64 interrupts, now;
1717	s64 delta;
1718
1719	raw_spin_lock(&ctx->lock);
1720	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
1721	if (event->state != PERF_EVENT_STATE_ACTIVE)
1722	continue;
1723
1724	if (!event_filter_match(event))
1725	continue;
1726
1727	hwc = &event->hw;
1728
1729	interrupts = hwc->interrupts;
1730	hwc->interrupts = 0;
1731
1732	/*
1733	* unthrottle events on the tick
1734	*/
1735	if (interrupts == MAX_INTERRUPTS) {
1736	perf_log_throttle(event, 1);
1737	event->pmu->start(event, 0);
1738	}
1739
1740	if (!event->attr.freq \|\| !event->attr.sample_freq)
1741	continue;
1742
1743	event->pmu->read(event);
1744	now = local64_read(&event->count);
1745	delta = now - hwc->freq_count_stamp;
1746	hwc->freq_count_stamp = now;
1747
1748	if (delta > 0)
1749	perf_adjust_period(event, period, delta);
1750	}
1751	raw_spin_unlock(&ctx->lock);
1752	}
1753
1754	/*
1755	* Round-robin a context's events:
1756	*/
1757	static void rotate_ctx(struct perf_event_context *ctx)
1758	{
1759	raw_spin_lock(&ctx->lock);
1760
1761	/*
1762	* Rotate the first entry last of non-pinned groups. Rotation might be
1763	* disabled by the inheritance code.
1764	*/
1765	if (!ctx->rotate_disable)
1766	list_rotate_left(&ctx->flexible_groups);
1767
1768	raw_spin_unlock(&ctx->lock);
1769	}
1770
1771	/*
1772	* perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
1773	* because they're strictly cpu affine and rotate_start is called with IRQs
1774	* disabled, while rotate_context is called from IRQ context.
1775	*/
1776	static void perf_rotate_context(struct perf_cpu_context *cpuctx)
1777	{
1778	u64 interval = (u64)cpuctx->jiffies_interval * TICK_NSEC;
1779	struct perf_event_context *ctx = NULL;
1780	int rotate = 0, remove = 1;
1781
1782	if (cpuctx->ctx.nr_events) {
1783	remove = 0;
1784	if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
1785	rotate = 1;
1786	}
1787
1788	ctx = cpuctx->task_ctx;
1789	if (ctx && ctx->nr_events) {
1790	remove = 0;
1791	if (ctx->nr_events != ctx->nr_active)
1792	rotate = 1;
1793	}
1794
1795	perf_pmu_disable(cpuctx->ctx.pmu);
1796	perf_ctx_adjust_freq(&cpuctx->ctx, interval);
1797	if (ctx)
1798	perf_ctx_adjust_freq(ctx, interval);
1799
1800	if (!rotate)
1801	goto done;
1802
1803	cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
1804	if (ctx)
1805	task_ctx_sched_out(ctx, EVENT_FLEXIBLE);
1806
1807	rotate_ctx(&cpuctx->ctx);
1808	if (ctx)
1809	rotate_ctx(ctx);
1810
1811	cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
1812	if (ctx)
1813	task_ctx_sched_in(ctx, EVENT_FLEXIBLE);
1814
1815	done:
1816	if (remove)
1817	list_del_init(&cpuctx->rotation_list);
1818
1819	perf_pmu_enable(cpuctx->ctx.pmu);
1820	}
1821
1822	void perf_event_task_tick(void)
1823	{
1824	struct list_head *head = &__get_cpu_var(rotation_list);
1825	struct perf_cpu_context cpuctx, tmp;
1826
1827	WARN_ON(!irqs_disabled());
1828
1829	list_for_each_entry_safe(cpuctx, tmp, head, rotation_list) {
1830	if (cpuctx->jiffies_interval == 1 \|\|
1831	!(jiffies % cpuctx->jiffies_interval))
1832	perf_rotate_context(cpuctx);
1833	}
1834	}
1835
1836	static int event_enable_on_exec(struct perf_event *event,
1837	struct perf_event_context *ctx)
1838	{
1839	if (!event->attr.enable_on_exec)
1840	return 0;
1841
1842	event->attr.enable_on_exec = 0;
1843	if (event->state >= PERF_EVENT_STATE_INACTIVE)
1844	return 0;
1845
1846	__perf_event_mark_enabled(event, ctx);
1847
1848	return 1;
1849	}
1850
1851	/*
1852	* Enable all of a task's events that have been marked enable-on-exec.
1853	* This expects task == current.
1854	*/
1855	static void perf_event_enable_on_exec(struct perf_event_context *ctx)
1856	{
1857	struct perf_event *event;
1858	unsigned long flags;
1859	int enabled = 0;
1860	int ret;
1861
1862	local_irq_save(flags);
1863	if (!ctx \|\| !ctx->nr_events)
1864	goto out;
1865
1866	task_ctx_sched_out(ctx, EVENT_ALL);
1867
1868	raw_spin_lock(&ctx->lock);
1869
1870	list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
1871	ret = event_enable_on_exec(event, ctx);
1872	if (ret)
1873	enabled = 1;
1874	}
1875
1876	list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
1877	ret = event_enable_on_exec(event, ctx);
1878	if (ret)
1879	enabled = 1;
1880	}
1881
1882	/*
1883	* Unclone this context if we enabled any event.
1884	*/
1885	if (enabled)
1886	unclone_ctx(ctx);
1887
1888	raw_spin_unlock(&ctx->lock);
1889
1890	perf_event_context_sched_in(ctx);
1891	out:
1892	local_irq_restore(flags);
1893	}
1894
1895	/*
1896	* Cross CPU call to read the hardware event
1897	*/
1898	static void __perf_event_read(void *info)
1899	{
1900	struct perf_event *event = info;
1901	struct perf_event_context *ctx = event->ctx;
1902	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1903
1904	/*
1905	* If this is a task context, we need to check whether it is
1906	* the current task context of this cpu. If not it has been
1907	* scheduled out before the smp call arrived. In that case
1908	* event->count would have been updated to a recent sample
1909	* when the event was scheduled out.
1910	*/
1911	if (ctx->task && cpuctx->task_ctx != ctx)
1912	return;
1913
1914	raw_spin_lock(&ctx->lock);
1915	if (ctx->is_active)
1916	update_context_time(ctx);
1917	update_event_times(event);
1918	if (event->state == PERF_EVENT_STATE_ACTIVE)
1919	event->pmu->read(event);
1920	raw_spin_unlock(&ctx->lock);
1921	}
1922
1923	static inline u64 perf_event_count(struct perf_event *event)
1924	{
1925	return local64_read(&event->count) + atomic64_read(&event->child_count);
1926	}
1927
1928	static u64 perf_event_read(struct perf_event *event)
1929	{
1930	/*
1931	* If event is enabled and currently active on a CPU, update the
1932	* value in the event structure:
1933	*/
1934	if (event->state == PERF_EVENT_STATE_ACTIVE) {
1935	smp_call_function_single(event->oncpu,
1936	__perf_event_read, event, 1);
1937	} else if (event->state == PERF_EVENT_STATE_INACTIVE) {
1938	struct perf_event_context *ctx = event->ctx;
1939	unsigned long flags;
1940
1941	raw_spin_lock_irqsave(&ctx->lock, flags);
1942	/*
1943	* may read while context is not active
1944	* (e.g., thread is blocked), in that case
1945	* we cannot update context time
1946	*/
1947	if (ctx->is_active)
1948	update_context_time(ctx);
1949	update_event_times(event);
1950	raw_spin_unlock_irqrestore(&ctx->lock, flags);
1951	}
1952
1953	return perf_event_count(event);
1954	}
1955
1956	/*
1957	* Callchain support
1958	*/
1959
1960	struct callchain_cpus_entries {
1961	struct rcu_head rcu_head;
1962	struct perf_callchain_entry *cpu_entries[0];
1963	};
1964
1965	static DEFINE_PER_CPU(int, callchain_recursion[PERF_NR_CONTEXTS]);
1966	static atomic_t nr_callchain_events;
1967	static DEFINE_MUTEX(callchain_mutex);
1968	struct callchain_cpus_entries *callchain_cpus_entries;
1969
1970
1971	__weak void perf_callchain_kernel(struct perf_callchain_entry *entry,
1972	struct pt_regs *regs)
1973	{
1974	}
1975
1976	__weak void perf_callchain_user(struct perf_callchain_entry *entry,
1977	struct pt_regs *regs)
1978	{
1979	}
1980
1981	static void release_callchain_buffers_rcu(struct rcu_head *head)
1982	{
1983	struct callchain_cpus_entries *entries;
1984	int cpu;
1985
1986	entries = container_of(head, struct callchain_cpus_entries, rcu_head);
1987
1988	for_each_possible_cpu(cpu)
1989	kfree(entries->cpu_entries[cpu]);
1990
1991	kfree(entries);
1992	}
1993
1994	static void release_callchain_buffers(void)
1995	{
1996	struct callchain_cpus_entries *entries;
1997
1998	entries = callchain_cpus_entries;
1999	rcu_assign_pointer(callchain_cpus_entries, NULL);
2000	call_rcu(&entries->rcu_head, release_callchain_buffers_rcu);
2001	}
2002
2003	static int alloc_callchain_buffers(void)
2004	{
2005	int cpu;
2006	int size;
2007	struct callchain_cpus_entries *entries;
2008
2009	/*
2010	* We can't use the percpu allocation API for data that can be
2011	* accessed from NMI. Use a temporary manual per cpu allocation
2012	* until that gets sorted out.
2013	*/
2014	size = offsetof(struct callchain_cpus_entries, cpu_entries[nr_cpu_ids]);
2015
2016	entries = kzalloc(size, GFP_KERNEL);
2017	if (!entries)
2018	return -ENOMEM;
2019
2020	size = sizeof(struct perf_callchain_entry) * PERF_NR_CONTEXTS;
2021
2022	for_each_possible_cpu(cpu) {
2023	entries->cpu_entries[cpu] = kmalloc_node(size, GFP_KERNEL,
2024	cpu_to_node(cpu));
2025	if (!entries->cpu_entries[cpu])
2026	goto fail;
2027	}
2028
2029	rcu_assign_pointer(callchain_cpus_entries, entries);
2030
2031	return 0;
2032
2033	fail:
2034	for_each_possible_cpu(cpu)
2035	kfree(entries->cpu_entries[cpu]);
2036	kfree(entries);
2037
2038	return -ENOMEM;
2039	}
2040
2041	static int get_callchain_buffers(void)
2042	{
2043	int err = 0;
2044	int count;
2045
2046	mutex_lock(&callchain_mutex);
2047
2048	count = atomic_inc_return(&nr_callchain_events);
2049	if (WARN_ON_ONCE(count < 1)) {
2050	err = -EINVAL;
2051	goto exit;
2052	}
2053
2054	if (count > 1) {
2055	/* If the allocation failed, give up */
2056	if (!callchain_cpus_entries)
2057	err = -ENOMEM;
2058	goto exit;
2059	}
2060
2061	err = alloc_callchain_buffers();
2062	if (err)
2063	release_callchain_buffers();
2064	exit:
2065	mutex_unlock(&callchain_mutex);
2066
2067	return err;
2068	}
2069
2070	static void put_callchain_buffers(void)
2071	{
2072	if (atomic_dec_and_mutex_lock(&nr_callchain_events, &callchain_mutex)) {
2073	release_callchain_buffers();
2074	mutex_unlock(&callchain_mutex);
2075	}
2076	}
2077
2078	static int get_recursion_context(int *recursion)
2079	{
2080	int rctx;
2081
2082	if (in_nmi())
2083	rctx = 3;
2084	else if (in_irq())
2085	rctx = 2;
2086	else if (in_softirq())
2087	rctx = 1;
2088	else
2089	rctx = 0;
2090
2091	if (recursion[rctx])
2092	return -1;
2093
2094	recursion[rctx]++;
2095	barrier();
2096
2097	return rctx;
2098	}
2099
2100	static inline void put_recursion_context(int *recursion, int rctx)
2101	{
2102	barrier();
2103	recursion[rctx]--;
2104	}
2105
2106	static struct perf_callchain_entry get_callchain_entry(int rctx)
2107	{
2108	int cpu;
2109	struct callchain_cpus_entries *entries;
2110
2111	*rctx = get_recursion_context(__get_cpu_var(callchain_recursion));
2112	if (*rctx == -1)
2113	return NULL;
2114
2115	entries = rcu_dereference(callchain_cpus_entries);
2116	if (!entries)
2117	return NULL;
2118
2119	cpu = smp_processor_id();
2120
2121	return &entries->cpu_entries[cpu][*rctx];
2122	}
2123
2124	static void
2125	put_callchain_entry(int rctx)
2126	{
2127	put_recursion_context(__get_cpu_var(callchain_recursion), rctx);
2128	}
2129
2130	static struct perf_callchain_entry perf_callchain(struct pt_regs regs)
2131	{
2132	int rctx;
2133	struct perf_callchain_entry *entry;
2134
2135
2136	entry = get_callchain_entry(&rctx);
2137	if (rctx == -1)
2138	return NULL;
2139
2140	if (!entry)
2141	goto exit_put;
2142
2143	entry->nr = 0;
2144
2145	if (!user_mode(regs)) {
2146	perf_callchain_store(entry, PERF_CONTEXT_KERNEL);
2147	perf_callchain_kernel(entry, regs);
2148	if (current->mm)
2149	regs = task_pt_regs(current);
2150	else
2151	regs = NULL;
2152	}
2153
2154	if (regs) {
2155	perf_callchain_store(entry, PERF_CONTEXT_USER);
2156	perf_callchain_user(entry, regs);
2157	}
2158
2159	exit_put:
2160	put_callchain_entry(rctx);
2161
2162	return entry;
2163	}
2164
2165	/*
2166	* Initialize the perf_event context in a task_struct:
2167	*/
2168	static void __perf_event_init_context(struct perf_event_context *ctx)
2169	{
2170	raw_spin_lock_init(&ctx->lock);
2171	mutex_init(&ctx->mutex);
2172	INIT_LIST_HEAD(&ctx->pinned_groups);
2173	INIT_LIST_HEAD(&ctx->flexible_groups);
2174	INIT_LIST_HEAD(&ctx->event_list);
2175	atomic_set(&ctx->refcount, 1);
2176	}
2177
2178	static struct perf_event_context *
2179	alloc_perf_context(struct pmu pmu, struct task_struct task)
2180	{
2181	struct perf_event_context *ctx;
2182
2183	ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
2184	if (!ctx)
2185	return NULL;
2186
2187	__perf_event_init_context(ctx);
2188	if (task) {
2189	ctx->task = task;
2190	get_task_struct(task);
2191	}
2192	ctx->pmu = pmu;
2193
2194	return ctx;
2195	}
2196
2197	static struct task_struct *
2198	find_lively_task_by_vpid(pid_t vpid)
2199	{
2200	struct task_struct *task;
2201	int err;
2202
2203	rcu_read_lock();
2204	if (!vpid)
2205	task = current;
2206	else
2207	task = find_task_by_vpid(vpid);
2208	if (task)
2209	get_task_struct(task);
2210	rcu_read_unlock();
2211
2212	if (!task)
2213	return ERR_PTR(-ESRCH);
2214
2215	/* Reuse ptrace permission checks for now. */
2216	err = -EACCES;
2217	if (!ptrace_may_access(task, PTRACE_MODE_READ))
2218	goto errout;
2219
2220	return task;
2221	errout:
2222	put_task_struct(task);
2223	return ERR_PTR(err);
2224
2225	}
2226
2227	static struct perf_event_context *
2228	find_get_context(struct pmu pmu, struct task_struct task, int cpu)
2229	{
2230	struct perf_event_context *ctx;
2231	struct perf_cpu_context *cpuctx;
2232	unsigned long flags;
2233	int ctxn, err;
2234
2235	if (!task) {
2236	/* Must be root to operate on a CPU event: */
2237	if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
2238	return ERR_PTR(-EACCES);
2239
2240	/*
2241	* We could be clever and allow to attach a event to an
2242	* offline CPU and activate it when the CPU comes up, but
2243	* that's for later.
2244	*/
2245	if (!cpu_online(cpu))
2246	return ERR_PTR(-ENODEV);
2247
2248	cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
2249	ctx = &cpuctx->ctx;
2250	get_ctx(ctx);
2251
2252	return ctx;
2253	}
2254
2255	err = -EINVAL;
2256	ctxn = pmu->task_ctx_nr;
2257	if (ctxn < 0)
2258	goto errout;
2259
2260	retry:
2261	ctx = perf_lock_task_context(task, ctxn, &flags);
2262	if (ctx) {
2263	unclone_ctx(ctx);
2264	raw_spin_unlock_irqrestore(&ctx->lock, flags);
2265	}
2266
2267	if (!ctx) {
2268	ctx = alloc_perf_context(pmu, task);
2269	err = -ENOMEM;
2270	if (!ctx)
2271	goto errout;
2272
2273	get_ctx(ctx);
2274
2275	err = 0;
2276	mutex_lock(&task->perf_event_mutex);
2277	/*
2278	* If it has already passed perf_event_exit_task().
2279	* we must see PF_EXITING, it takes this mutex too.
2280	*/
2281	if (task->flags & PF_EXITING)
2282	err = -ESRCH;
2283	else if (task->perf_event_ctxp[ctxn])
2284	err = -EAGAIN;
2285	else
2286	rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
2287	mutex_unlock(&task->perf_event_mutex);
2288
2289	if (unlikely(err)) {
2290	put_task_struct(task);
2291	kfree(ctx);
2292
2293	if (err == -EAGAIN)
2294	goto retry;
2295	goto errout;
2296	}
2297	}
2298
2299	return ctx;
2300
2301	errout:
2302	return ERR_PTR(err);
2303	}
2304
2305	static void perf_event_free_filter(struct perf_event *event);
2306
2307	static void free_event_rcu(struct rcu_head *head)
2308	{
2309	struct perf_event *event;
2310
2311	event = container_of(head, struct perf_event, rcu_head);
2312	if (event->ns)
2313	put_pid_ns(event->ns);
2314	perf_event_free_filter(event);
2315	kfree(event);
2316	}
2317
2318	static void perf_buffer_put(struct perf_buffer *buffer);
2319
2320	static void free_event(struct perf_event *event)
2321	{
2322	irq_work_sync(&event->pending);
2323
2324	if (!event->parent) {
2325	if (event->attach_state & PERF_ATTACH_TASK)
2326	jump_label_dec(&perf_task_events);
2327	if (event->attr.mmap \|\| event->attr.mmap_data)
2328	atomic_dec(&nr_mmap_events);
2329	if (event->attr.comm)
2330	atomic_dec(&nr_comm_events);
2331	if (event->attr.task)
2332	atomic_dec(&nr_task_events);
2333	if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
2334	put_callchain_buffers();
2335	}
2336
2337	if (event->buffer) {
2338	perf_buffer_put(event->buffer);
2339	event->buffer = NULL;
2340	}
2341
2342	if (event->destroy)
2343	event->destroy(event);
2344
2345	if (event->ctx)
2346	put_ctx(event->ctx);
2347
2348	call_rcu(&event->rcu_head, free_event_rcu);
2349	}
2350
2351	int perf_event_release_kernel(struct perf_event *event)
2352	{
2353	struct perf_event_context *ctx = event->ctx;
2354
2355	/*
2356	* Remove from the PMU, can't get re-enabled since we got
2357	* here because the last ref went.
2358	*/
2359	perf_event_disable(event);
2360
2361	WARN_ON_ONCE(ctx->parent_ctx);
2362	/*
2363	* There are two ways this annotation is useful:
2364	*
2365	* 1) there is a lock recursion from perf_event_exit_task
2366	* see the comment there.
2367	*
2368	* 2) there is a lock-inversion with mmap_sem through
2369	* perf_event_read_group(), which takes faults while
2370	* holding ctx->mutex, however this is called after
2371	* the last filedesc died, so there is no possibility
2372	* to trigger the AB-BA case.
2373	*/
2374	mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING);
2375	raw_spin_lock_irq(&ctx->lock);
2376	perf_group_detach(event);
2377	list_del_event(event, ctx);
2378	raw_spin_unlock_irq(&ctx->lock);
2379	mutex_unlock(&ctx->mutex);
2380
2381	free_event(event);
2382
2383	return 0;
2384	}
2385	EXPORT_SYMBOL_GPL(perf_event_release_kernel);
2386
2387	/*
2388	* Called when the last reference to the file is gone.
2389	*/
2390	static int perf_release(struct inode inode, struct file file)
2391	{
2392	struct perf_event *event = file->private_data;
2393	struct task_struct *owner;
2394
2395	file->private_data = NULL;
2396
2397	rcu_read_lock();
2398	owner = ACCESS_ONCE(event->owner);
2399	/*
2400	* Matches the smp_wmb() in perf_event_exit_task(). If we observe
2401	* !owner it means the list deletion is complete and we can indeed
2402	* free this event, otherwise we need to serialize on
2403	* owner->perf_event_mutex.
2404	*/
2405	smp_read_barrier_depends();
2406	if (owner) {
2407	/*
2408	* Since delayed_put_task_struct() also drops the last
2409	* task reference we can safely take a new reference
2410	* while holding the rcu_read_lock().
2411	*/
2412	get_task_struct(owner);
2413	}
2414	rcu_read_unlock();
2415
2416	if (owner) {
2417	mutex_lock(&owner->perf_event_mutex);
2418	/*
2419	* We have to re-check the event->owner field, if it is cleared
2420	* we raced with perf_event_exit_task(), acquiring the mutex
2421	* ensured they're done, and we can proceed with freeing the
2422	* event.
2423	*/
2424	if (event->owner)
2425	list_del_init(&event->owner_entry);
2426	mutex_unlock(&owner->perf_event_mutex);
2427	put_task_struct(owner);
2428	}
2429
2430	return perf_event_release_kernel(event);
2431	}
2432
2433	u64 perf_event_read_value(struct perf_event event, u64 enabled, u64 *running)
2434	{
2435	struct perf_event *child;
2436	u64 total = 0;
2437
2438	*enabled = 0;
2439	*running = 0;
2440
2441	mutex_lock(&event->child_mutex);
2442	total += perf_event_read(event);
2443	*enabled += event->total_time_enabled +
2444	atomic64_read(&event->child_total_time_enabled);
2445	*running += event->total_time_running +
2446	atomic64_read(&event->child_total_time_running);
2447
2448	list_for_each_entry(child, &event->child_list, child_list) {
2449	total += perf_event_read(child);
2450	*enabled += child->total_time_enabled;
2451	*running += child->total_time_running;
2452	}
2453	mutex_unlock(&event->child_mutex);
2454
2455	return total;
2456	}
2457	EXPORT_SYMBOL_GPL(perf_event_read_value);
2458
2459	static int perf_event_read_group(struct perf_event *event,
2460	u64 read_format, char __user *buf)
2461	{
2462	struct perf_event leader = event->group_leader, sub;
2463	int n = 0, size = 0, ret = -EFAULT;
2464	struct perf_event_context *ctx = leader->ctx;
2465	u64 values[5];
2466	u64 count, enabled, running;
2467
2468	mutex_lock(&ctx->mutex);
2469	count = perf_event_read_value(leader, &enabled, &running);
2470
2471	values[n++] = 1 + leader->nr_siblings;
2472	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
2473	values[n++] = enabled;
2474	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
2475	values[n++] = running;
2476	values[n++] = count;
2477	if (read_format & PERF_FORMAT_ID)
2478	values[n++] = primary_event_id(leader);
2479
2480	size = n * sizeof(u64);
2481
2482	if (copy_to_user(buf, values, size))
2483	goto unlock;
2484
2485	ret = size;
2486
2487	list_for_each_entry(sub, &leader->sibling_list, group_entry) {
2488	n = 0;
2489
2490	values[n++] = perf_event_read_value(sub, &enabled, &running);
2491	if (read_format & PERF_FORMAT_ID)
2492	values[n++] = primary_event_id(sub);
2493
2494	size = n * sizeof(u64);
2495
2496	if (copy_to_user(buf + ret, values, size)) {
2497	ret = -EFAULT;
2498	goto unlock;
2499	}
2500
2501	ret += size;
2502	}
2503	unlock:
2504	mutex_unlock(&ctx->mutex);
2505
2506	return ret;
2507	}
2508
2509	static int perf_event_read_one(struct perf_event *event,
2510	u64 read_format, char __user *buf)
2511	{
2512	u64 enabled, running;
2513	u64 values[4];
2514	int n = 0;
2515
2516	values[n++] = perf_event_read_value(event, &enabled, &running);
2517	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
2518	values[n++] = enabled;
2519	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
2520	values[n++] = running;
2521	if (read_format & PERF_FORMAT_ID)
2522	values[n++] = primary_event_id(event);
2523
2524	if (copy_to_user(buf, values, n * sizeof(u64)))
2525	return -EFAULT;
2526
2527	return n * sizeof(u64);
2528	}
2529
2530	/*
2531	* Read the performance event - simple non blocking version for now
2532	*/
2533	static ssize_t
2534	perf_read_hw(struct perf_event event, char __user buf, size_t count)
2535	{
2536	u64 read_format = event->attr.read_format;
2537	int ret;
2538
2539	/*
2540	* Return end-of-file for a read on a event that is in
2541	* error state (i.e. because it was pinned but it couldn't be
2542	* scheduled on to the CPU at some point).
2543	*/
2544	if (event->state == PERF_EVENT_STATE_ERROR)
2545	return 0;
2546
2547	if (count < event->read_size)
2548	return -ENOSPC;
2549
2550	WARN_ON_ONCE(event->ctx->parent_ctx);
2551	if (read_format & PERF_FORMAT_GROUP)
2552	ret = perf_event_read_group(event, read_format, buf);
2553	else
2554	ret = perf_event_read_one(event, read_format, buf);
2555
2556	return ret;
2557	}
2558
2559	static ssize_t
2560	perf_read(struct file file, char __user buf, size_t count, loff_t *ppos)
2561	{
2562	struct perf_event *event = file->private_data;
2563
2564	return perf_read_hw(event, buf, count);
2565	}
2566
2567	static unsigned int perf_poll(struct file file, poll_table wait)
2568	{
2569	struct perf_event *event = file->private_data;
2570	struct perf_buffer *buffer;
2571	unsigned int events = POLL_HUP;
2572
2573	rcu_read_lock();
2574	buffer = rcu_dereference(event->buffer);
2575	if (buffer)
2576	events = atomic_xchg(&buffer->poll, 0);
2577	rcu_read_unlock();
2578
2579	poll_wait(file, &event->waitq, wait);
2580
2581	return events;
2582	}
2583
2584	static void perf_event_reset(struct perf_event *event)
2585	{
2586	(void)perf_event_read(event);
2587	local64_set(&event->count, 0);
2588	perf_event_update_userpage(event);
2589	}
2590
2591	/*
2592	* Holding the top-level event's child_mutex means that any
2593	* descendant process that has inherited this event will block
2594	* in sync_child_event if it goes to exit, thus satisfying the
2595	* task existence requirements of perf_event_enable/disable.
2596	*/
2597	static void perf_event_for_each_child(struct perf_event *event,
2598	void (func)(struct perf_event ))
2599	{
2600	struct perf_event *child;
2601
2602	WARN_ON_ONCE(event->ctx->parent_ctx);
2603	mutex_lock(&event->child_mutex);
2604	func(event);
2605	list_for_each_entry(child, &event->child_list, child_list)
2606	func(child);
2607	mutex_unlock(&event->child_mutex);
2608	}
2609
2610	static void perf_event_for_each(struct perf_event *event,
2611	void (func)(struct perf_event ))
2612	{
2613	struct perf_event_context *ctx = event->ctx;
2614	struct perf_event *sibling;
2615
2616	WARN_ON_ONCE(ctx->parent_ctx);
2617	mutex_lock(&ctx->mutex);
2618	event = event->group_leader;
2619
2620	perf_event_for_each_child(event, func);
2621	func(event);
2622	list_for_each_entry(sibling, &event->sibling_list, group_entry)
2623	perf_event_for_each_child(event, func);
2624	mutex_unlock(&ctx->mutex);
2625	}
2626
2627	static int perf_event_period(struct perf_event event, u64 __user arg)
2628	{
2629	struct perf_event_context *ctx = event->ctx;
2630	int ret = 0;
2631	u64 value;
2632
2633	if (!is_sampling_event(event))
2634	return -EINVAL;
2635
2636	if (copy_from_user(&value, arg, sizeof(value)))
2637	return -EFAULT;
2638
2639	if (!value)
2640	return -EINVAL;
2641
2642	raw_spin_lock_irq(&ctx->lock);
2643	if (event->attr.freq) {
2644	if (value > sysctl_perf_event_sample_rate) {
2645	ret = -EINVAL;
2646	goto unlock;
2647	}
2648
2649	event->attr.sample_freq = value;
2650	} else {
2651	event->attr.sample_period = value;
2652	event->hw.sample_period = value;
2653	}
2654	unlock:
2655	raw_spin_unlock_irq(&ctx->lock);
2656
2657	return ret;
2658	}
2659
2660	static const struct file_operations perf_fops;
2661
2662	static struct perf_event perf_fget_light(int fd, int fput_needed)
2663	{
2664	struct file *file;
2665
2666	file = fget_light(fd, fput_needed);
2667	if (!file)
2668	return ERR_PTR(-EBADF);
2669
2670	if (file->f_op != &perf_fops) {
2671	fput_light(file, *fput_needed);
2672	*fput_needed = 0;
2673	return ERR_PTR(-EBADF);
2674	}
2675
2676	return file->private_data;
2677	}
2678
2679	static int perf_event_set_output(struct perf_event *event,
2680	struct perf_event *output_event);
2681	static int perf_event_set_filter(struct perf_event event, void __user arg);
2682
2683	static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2684	{
2685	struct perf_event *event = file->private_data;
2686	void (func)(struct perf_event );
2687	u32 flags = arg;
2688
2689	switch (cmd) {
2690	case PERF_EVENT_IOC_ENABLE:
2691	func = perf_event_enable;
2692	break;
2693	case PERF_EVENT_IOC_DISABLE:
2694	func = perf_event_disable;
2695	break;
2696	case PERF_EVENT_IOC_RESET:
2697	func = perf_event_reset;
2698	break;
2699
2700	case PERF_EVENT_IOC_REFRESH:
2701	return perf_event_refresh(event, arg);
2702
2703	case PERF_EVENT_IOC_PERIOD:
2704	return perf_event_period(event, (u64 __user *)arg);
2705
2706	case PERF_EVENT_IOC_SET_OUTPUT:
2707	{
2708	struct perf_event *output_event = NULL;
2709	int fput_needed = 0;
2710	int ret;
2711
2712	if (arg != -1) {
2713	output_event = perf_fget_light(arg, &fput_needed);
2714	if (IS_ERR(output_event))
2715	return PTR_ERR(output_event);
2716	}
2717
2718	ret = perf_event_set_output(event, output_event);
2719	if (output_event)
2720	fput_light(output_event->filp, fput_needed);
2721
2722	return ret;
2723	}
2724
2725	case PERF_EVENT_IOC_SET_FILTER:
2726	return perf_event_set_filter(event, (void __user *)arg);
2727
2728	default:
2729	return -ENOTTY;
2730	}
2731
2732	if (flags & PERF_IOC_FLAG_GROUP)
2733	perf_event_for_each(event, func);
2734	else
2735	perf_event_for_each_child(event, func);
2736
2737	return 0;
2738	}
2739
2740	int perf_event_task_enable(void)
2741	{
2742	struct perf_event *event;
2743
2744	mutex_lock(&current->perf_event_mutex);
2745	list_for_each_entry(event, &current->perf_event_list, owner_entry)
2746	perf_event_for_each_child(event, perf_event_enable);
2747	mutex_unlock(&current->perf_event_mutex);
2748
2749	return 0;
2750	}
2751
2752	int perf_event_task_disable(void)
2753	{
2754	struct perf_event *event;
2755
2756	mutex_lock(&current->perf_event_mutex);
2757	list_for_each_entry(event, &current->perf_event_list, owner_entry)
2758	perf_event_for_each_child(event, perf_event_disable);
2759	mutex_unlock(&current->perf_event_mutex);
2760
2761	return 0;
2762	}
2763
2764	#ifndef PERF_EVENT_INDEX_OFFSET
2765	# define PERF_EVENT_INDEX_OFFSET 0
2766	#endif
2767
2768	static int perf_event_index(struct perf_event *event)
2769	{
2770	if (event->hw.state & PERF_HES_STOPPED)
2771	return 0;
2772
2773	if (event->state != PERF_EVENT_STATE_ACTIVE)
2774	return 0;
2775
2776	return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET;
2777	}
2778
2779	/*
2780	* Callers need to ensure there can be no nesting of this function, otherwise
2781	* the seqlock logic goes bad. We can not serialize this because the arch
2782	* code calls this from NMI context.
2783	*/
2784	void perf_event_update_userpage(struct perf_event *event)
2785	{
2786	struct perf_event_mmap_page *userpg;
2787	struct perf_buffer *buffer;
2788
2789	rcu_read_lock();
2790	buffer = rcu_dereference(event->buffer);
2791	if (!buffer)
2792	goto unlock;
2793
2794	userpg = buffer->user_page;
2795
2796	/*
2797	* Disable preemption so as to not let the corresponding user-space
2798	* spin too long if we get preempted.
2799	*/
2800	preempt_disable();
2801	++userpg->lock;
2802	barrier();
2803	userpg->index = perf_event_index(event);
2804	userpg->offset = perf_event_count(event);
2805	if (event->state == PERF_EVENT_STATE_ACTIVE)
2806	userpg->offset -= local64_read(&event->hw.prev_count);
2807
2808	userpg->time_enabled = event->total_time_enabled +
2809	atomic64_read(&event->child_total_time_enabled);
2810
2811	userpg->time_running = event->total_time_running +
2812	atomic64_read(&event->child_total_time_running);
2813
2814	barrier();
2815	++userpg->lock;
2816	preempt_enable();
2817	unlock:
2818	rcu_read_unlock();
2819	}
2820
2821	static unsigned long perf_data_size(struct perf_buffer *buffer);
2822
2823	static void
2824	perf_buffer_init(struct perf_buffer *buffer, long watermark, int flags)
2825	{
2826	long max_size = perf_data_size(buffer);
2827
2828	if (watermark)
2829	buffer->watermark = min(max_size, watermark);
2830
2831	if (!buffer->watermark)
2832	buffer->watermark = max_size / 2;
2833
2834	if (flags & PERF_BUFFER_WRITABLE)
2835	buffer->writable = 1;
2836
2837	atomic_set(&buffer->refcount, 1);
2838	}
2839
2840	#ifndef CONFIG_PERF_USE_VMALLOC
2841
2842	/*
2843	* Back perf_mmap() with regular GFP_KERNEL-0 pages.
2844	*/
2845
2846	static struct page *
2847	perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
2848	{
2849	if (pgoff > buffer->nr_pages)
2850	return NULL;
2851
2852	if (pgoff == 0)
2853	return virt_to_page(buffer->user_page);
2854
2855	return virt_to_page(buffer->data_pages[pgoff - 1]);
2856	}
2857
2858	static void *perf_mmap_alloc_page(int cpu)
2859	{
2860	struct page *page;
2861	int node;
2862
2863	node = (cpu == -1) ? cpu : cpu_to_node(cpu);
2864	page = alloc_pages_node(node, GFP_KERNEL \| __GFP_ZERO, 0);
2865	if (!page)
2866	return NULL;
2867
2868	return page_address(page);
2869	}
2870
2871	static struct perf_buffer *
2872	perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
2873	{
2874	struct perf_buffer *buffer;
2875	unsigned long size;
2876	int i;
2877
2878	size = sizeof(struct perf_buffer);
2879	size += nr_pages * sizeof(void *);
2880
2881	buffer = kzalloc(size, GFP_KERNEL);
2882	if (!buffer)
2883	goto fail;
2884
2885	buffer->user_page = perf_mmap_alloc_page(cpu);
2886	if (!buffer->user_page)
2887	goto fail_user_page;
2888
2889	for (i = 0; i < nr_pages; i++) {
2890	buffer->data_pages[i] = perf_mmap_alloc_page(cpu);
2891	if (!buffer->data_pages[i])
2892	goto fail_data_pages;
2893	}
2894
2895	buffer->nr_pages = nr_pages;
2896
2897	perf_buffer_init(buffer, watermark, flags);
2898
2899	return buffer;
2900
2901	fail_data_pages:
2902	for (i--; i >= 0; i--)
2903	free_page((unsigned long)buffer->data_pages[i]);
2904
2905	free_page((unsigned long)buffer->user_page);
2906
2907	fail_user_page:
2908	kfree(buffer);
2909
2910	fail:
2911	return NULL;
2912	}
2913
2914	static void perf_mmap_free_page(unsigned long addr)
2915	{
2916	struct page page = virt_to_page((void )addr);
2917
2918	page->mapping = NULL;
2919	__free_page(page);
2920	}
2921
2922	static void perf_buffer_free(struct perf_buffer *buffer)
2923	{
2924	int i;
2925
2926	perf_mmap_free_page((unsigned long)buffer->user_page);
2927	for (i = 0; i < buffer->nr_pages; i++)
2928	perf_mmap_free_page((unsigned long)buffer->data_pages[i]);
2929	kfree(buffer);
2930	}
2931
2932	static inline int page_order(struct perf_buffer *buffer)
2933	{
2934	return 0;
2935	}
2936
2937	#else
2938
2939	/*
2940	* Back perf_mmap() with vmalloc memory.
2941	*
2942	* Required for architectures that have d-cache aliasing issues.
2943	*/
2944
2945	static inline int page_order(struct perf_buffer *buffer)
2946	{
2947	return buffer->page_order;
2948	}
2949
2950	static struct page *
2951	perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
2952	{
2953	if (pgoff > (1UL << page_order(buffer)))
2954	return NULL;
2955
2956	return vmalloc_to_page((void )buffer->user_page + pgoff PAGE_SIZE);
2957	}
2958
2959	static void perf_mmap_unmark_page(void *addr)
2960	{
2961	struct page *page = vmalloc_to_page(addr);
2962
2963	page->mapping = NULL;
2964	}
2965
2966	static void perf_buffer_free_work(struct work_struct *work)
2967	{
2968	struct perf_buffer *buffer;
2969	void *base;
2970	int i, nr;
2971
2972	buffer = container_of(work, struct perf_buffer, work);
2973	nr = 1 << page_order(buffer);
2974
2975	base = buffer->user_page;
2976	for (i = 0; i < nr + 1; i++)
2977	perf_mmap_unmark_page(base + (i * PAGE_SIZE));
2978
2979	vfree(base);
2980	kfree(buffer);
2981	}
2982
2983	static void perf_buffer_free(struct perf_buffer *buffer)
2984	{
2985	schedule_work(&buffer->work);
2986	}
2987
2988	static struct perf_buffer *
2989	perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
2990	{
2991	struct perf_buffer *buffer;
2992	unsigned long size;
2993	void *all_buf;
2994
2995	size = sizeof(struct perf_buffer);
2996	size += sizeof(void *);
2997
2998	buffer = kzalloc(size, GFP_KERNEL);
2999	if (!buffer)
3000	goto fail;
3001
3002	INIT_WORK(&buffer->work, perf_buffer_free_work);
3003
3004	all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
3005	if (!all_buf)
3006	goto fail_all_buf;
3007
3008	buffer->user_page = all_buf;
3009	buffer->data_pages[0] = all_buf + PAGE_SIZE;
3010	buffer->page_order = ilog2(nr_pages);
3011	buffer->nr_pages = 1;
3012
3013	perf_buffer_init(buffer, watermark, flags);
3014
3015	return buffer;
3016
3017	fail_all_buf:
3018	kfree(buffer);
3019
3020	fail:
3021	return NULL;
3022	}
3023
3024	#endif
3025
3026	static unsigned long perf_data_size(struct perf_buffer *buffer)
3027	{
3028	return buffer->nr_pages << (PAGE_SHIFT + page_order(buffer));
3029	}
3030
3031	static int perf_mmap_fault(struct vm_area_struct vma, struct vm_fault vmf)
3032	{
3033	struct perf_event *event = vma->vm_file->private_data;
3034	struct perf_buffer *buffer;
3035	int ret = VM_FAULT_SIGBUS;
3036
3037	if (vmf->flags & FAULT_FLAG_MKWRITE) {
3038	if (vmf->pgoff == 0)
3039	ret = 0;
3040	return ret;
3041	}
3042
3043	rcu_read_lock();
3044	buffer = rcu_dereference(event->buffer);
3045	if (!buffer)
3046	goto unlock;
3047
3048	if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
3049	goto unlock;
3050
3051	vmf->page = perf_mmap_to_page(buffer, vmf->pgoff);
3052	if (!vmf->page)
3053	goto unlock;
3054
3055	get_page(vmf->page);
3056	vmf->page->mapping = vma->vm_file->f_mapping;
3057	vmf->page->index = vmf->pgoff;
3058
3059	ret = 0;
3060	unlock:
3061	rcu_read_unlock();
3062
3063	return ret;
3064	}
3065
3066	static void perf_buffer_free_rcu(struct rcu_head *rcu_head)
3067	{
3068	struct perf_buffer *buffer;
3069
3070	buffer = container_of(rcu_head, struct perf_buffer, rcu_head);
3071	perf_buffer_free(buffer);
3072	}
3073
3074	static struct perf_buffer perf_buffer_get(struct perf_event event)
3075	{
3076	struct perf_buffer *buffer;
3077
3078	rcu_read_lock();
3079	buffer = rcu_dereference(event->buffer);
3080	if (buffer) {
3081	if (!atomic_inc_not_zero(&buffer->refcount))
3082	buffer = NULL;
3083	}
3084	rcu_read_unlock();
3085
3086	return buffer;
3087	}
3088
3089	static void perf_buffer_put(struct perf_buffer *buffer)
3090	{
3091	if (!atomic_dec_and_test(&buffer->refcount))
3092	return;
3093
3094	call_rcu(&buffer->rcu_head, perf_buffer_free_rcu);
3095	}
3096
3097	static void perf_mmap_open(struct vm_area_struct *vma)
3098	{
3099	struct perf_event *event = vma->vm_file->private_data;
3100
3101	atomic_inc(&event->mmap_count);
3102	}
3103
3104	static void perf_mmap_close(struct vm_area_struct *vma)
3105	{
3106	struct perf_event *event = vma->vm_file->private_data;
3107
3108	if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
3109	unsigned long size = perf_data_size(event->buffer);
3110	struct user_struct *user = event->mmap_user;
3111	struct perf_buffer *buffer = event->buffer;
3112
3113	atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
3114	vma->vm_mm->locked_vm -= event->mmap_locked;
3115	rcu_assign_pointer(event->buffer, NULL);
3116	mutex_unlock(&event->mmap_mutex);
3117
3118	perf_buffer_put(buffer);
3119	free_uid(user);
3120	}
3121	}
3122
3123	static const struct vm_operations_struct perf_mmap_vmops = {
3124	.open = perf_mmap_open,
3125	.close = perf_mmap_close,
3126	.fault = perf_mmap_fault,
3127	.page_mkwrite = perf_mmap_fault,
3128	};
3129
3130	static int perf_mmap(struct file file, struct vm_area_struct vma)
3131	{
3132	struct perf_event *event = file->private_data;
3133	unsigned long user_locked, user_lock_limit;
3134	struct user_struct *user = current_user();
3135	unsigned long locked, lock_limit;
3136	struct perf_buffer *buffer;
3137	unsigned long vma_size;
3138	unsigned long nr_pages;
3139	long user_extra, extra;
3140	int ret = 0, flags = 0;
3141
3142	/*
3143	* Don't allow mmap() of inherited per-task counters. This would
3144	* create a performance issue due to all children writing to the
3145	* same buffer.
3146	*/
3147	if (event->cpu == -1 && event->attr.inherit)
3148	return -EINVAL;
3149
3150	if (!(vma->vm_flags & VM_SHARED))
3151	return -EINVAL;
3152
3153	vma_size = vma->vm_end - vma->vm_start;
3154	nr_pages = (vma_size / PAGE_SIZE) - 1;
3155
3156	/*
3157	* If we have buffer pages ensure they're a power-of-two number, so we
3158	* can do bitmasks instead of modulo.
3159	*/
3160	if (nr_pages != 0 && !is_power_of_2(nr_pages))
3161	return -EINVAL;
3162
3163	if (vma_size != PAGE_SIZE * (1 + nr_pages))
3164	return -EINVAL;
3165
3166	if (vma->vm_pgoff != 0)
3167	return -EINVAL;
3168
3169	WARN_ON_ONCE(event->ctx->parent_ctx);
3170	mutex_lock(&event->mmap_mutex);
3171	if (event->buffer) {
3172	if (event->buffer->nr_pages == nr_pages)
3173	atomic_inc(&event->buffer->refcount);
3174	else
3175	ret = -EINVAL;
3176	goto unlock;
3177	}
3178
3179	user_extra = nr_pages + 1;
3180	user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
3181
3182	/*
3183	* Increase the limit linearly with more CPUs:
3184	*/
3185	user_lock_limit *= num_online_cpus();
3186
3187	user_locked = atomic_long_read(&user->locked_vm) + user_extra;
3188
3189	extra = 0;
3190	if (user_locked > user_lock_limit)
3191	extra = user_locked - user_lock_limit;
3192
3193	lock_limit = rlimit(RLIMIT_MEMLOCK);
3194	lock_limit >>= PAGE_SHIFT;
3195	locked = vma->vm_mm->locked_vm + extra;
3196
3197	if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
3198	!capable(CAP_IPC_LOCK)) {
3199	ret = -EPERM;
3200	goto unlock;
3201	}
3202
3203	WARN_ON(event->buffer);
3204
3205	if (vma->vm_flags & VM_WRITE)
3206	flags \|= PERF_BUFFER_WRITABLE;
3207
3208	buffer = perf_buffer_alloc(nr_pages, event->attr.wakeup_watermark,
3209	event->cpu, flags);
3210	if (!buffer) {
3211	ret = -ENOMEM;
3212	goto unlock;
3213	}
3214	rcu_assign_pointer(event->buffer, buffer);
3215
3216	atomic_long_add(user_extra, &user->locked_vm);
3217	event->mmap_locked = extra;
3218	event->mmap_user = get_current_user();
3219	vma->vm_mm->locked_vm += event->mmap_locked;
3220
3221	unlock:
3222	if (!ret)
3223	atomic_inc(&event->mmap_count);
3224	mutex_unlock(&event->mmap_mutex);
3225
3226	vma->vm_flags \|= VM_RESERVED;
3227	vma->vm_ops = &perf_mmap_vmops;
3228
3229	return ret;
3230	}
3231
3232	static int perf_fasync(int fd, struct file *filp, int on)
3233	{
3234	struct inode *inode = filp->f_path.dentry->d_inode;
3235	struct perf_event *event = filp->private_data;
3236	int retval;
3237
3238	mutex_lock(&inode->i_mutex);
3239	retval = fasync_helper(fd, filp, on, &event->fasync);
3240	mutex_unlock(&inode->i_mutex);
3241
3242	if (retval < 0)
3243	return retval;
3244
3245	return 0;
3246	}
3247
3248	static const struct file_operations perf_fops = {
3249	.llseek = no_llseek,
3250	.release = perf_release,
3251	.read = perf_read,
3252	.poll = perf_poll,
3253	.unlocked_ioctl = perf_ioctl,
3254	.compat_ioctl = perf_ioctl,
3255	.mmap = perf_mmap,
3256	.fasync = perf_fasync,
3257	};
3258
3259	/*
3260	* Perf event wakeup
3261	*
3262	* If there's data, ensure we set the poll() state and publish everything
3263	* to user-space before waking everybody up.
3264	*/
3265
3266	void perf_event_wakeup(struct perf_event *event)
3267	{
3268	wake_up_all(&event->waitq);
3269
3270	if (event->pending_kill) {
3271	kill_fasync(&event->fasync, SIGIO, event->pending_kill);
3272	event->pending_kill = 0;
3273	}
3274	}
3275
3276	static void perf_pending_event(struct irq_work *entry)
3277	{
3278	struct perf_event *event = container_of(entry,
3279	struct perf_event, pending);
3280
3281	if (event->pending_disable) {
3282	event->pending_disable = 0;
3283	__perf_event_disable(event);
3284	}
3285
3286	if (event->pending_wakeup) {
3287	event->pending_wakeup = 0;
3288	perf_event_wakeup(event);
3289	}
3290	}
3291
3292	/*
3293	* We assume there is only KVM supporting the callbacks.
3294	* Later on, we might change it to a list if there is
3295	* another virtualization implementation supporting the callbacks.
3296	*/
3297	struct perf_guest_info_callbacks *perf_guest_cbs;
3298
3299	int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
3300	{
3301	perf_guest_cbs = cbs;
3302	return 0;
3303	}
3304	EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
3305
3306	int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
3307	{
3308	perf_guest_cbs = NULL;
3309	return 0;
3310	}
3311	EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
3312
3313	/*
3314	* Output
3315	*/
3316	static bool perf_output_space(struct perf_buffer *buffer, unsigned long tail,
3317	unsigned long offset, unsigned long head)
3318	{
3319	unsigned long mask;
3320
3321	if (!buffer->writable)
3322	return true;
3323
3324	mask = perf_data_size(buffer) - 1;
3325
3326	offset = (offset - tail) & mask;
3327	head = (head - tail) & mask;
3328
3329	if ((int)(head - offset) < 0)
3330	return false;
3331
3332	return true;
3333	}
3334
3335	static void perf_output_wakeup(struct perf_output_handle *handle)
3336	{
3337	atomic_set(&handle->buffer->poll, POLL_IN);
3338
3339	if (handle->nmi) {
3340	handle->event->pending_wakeup = 1;
3341	irq_work_queue(&handle->event->pending);
3342	} else
3343	perf_event_wakeup(handle->event);
3344	}
3345
3346	/*
3347	* We need to ensure a later event_id doesn't publish a head when a former
3348	* event isn't done writing. However since we need to deal with NMIs we
3349	* cannot fully serialize things.
3350	*
3351	* We only publish the head (and generate a wakeup) when the outer-most
3352	* event completes.
3353	*/
3354	static void perf_output_get_handle(struct perf_output_handle *handle)
3355	{
3356	struct perf_buffer *buffer = handle->buffer;
3357
3358	preempt_disable();
3359	local_inc(&buffer->nest);
3360	handle->wakeup = local_read(&buffer->wakeup);
3361	}
3362
3363	static void perf_output_put_handle(struct perf_output_handle *handle)
3364	{
3365	struct perf_buffer *buffer = handle->buffer;
3366	unsigned long head;
3367
3368	again:
3369	head = local_read(&buffer->head);
3370
3371	/*
3372	* IRQ/NMI can happen here, which means we can miss a head update.
3373	*/
3374
3375	if (!local_dec_and_test(&buffer->nest))
3376	goto out;
3377
3378	/*
3379	* Publish the known good head. Rely on the full barrier implied
3380	* by atomic_dec_and_test() order the buffer->head read and this
3381	* write.
3382	*/
3383	buffer->user_page->data_head = head;
3384
3385	/*
3386	* Now check if we missed an update, rely on the (compiler)
3387	* barrier in atomic_dec_and_test() to re-read buffer->head.
3388	*/
3389	if (unlikely(head != local_read(&buffer->head))) {
3390	local_inc(&buffer->nest);
3391	goto again;
3392	}
3393
3394	if (handle->wakeup != local_read(&buffer->wakeup))
3395	perf_output_wakeup(handle);
3396
3397	out:
3398	preempt_enable();
3399	}
3400
3401	__always_inline void perf_output_copy(struct perf_output_handle *handle,
3402	const void *buf, unsigned int len)
3403	{
3404	do {
3405	unsigned long size = min_t(unsigned long, handle->size, len);
3406
3407	memcpy(handle->addr, buf, size);
3408
3409	len -= size;
3410	handle->addr += size;
3411	buf += size;
3412	handle->size -= size;
3413	if (!handle->size) {
3414	struct perf_buffer *buffer = handle->buffer;
3415
3416	handle->page++;
3417	handle->page &= buffer->nr_pages - 1;
3418	handle->addr = buffer->data_pages[handle->page];
3419	handle->size = PAGE_SIZE << page_order(buffer);
3420	}
3421	} while (len);
3422	}
3423
3424	static void __perf_event_header__init_id(struct perf_event_header *header,
3425	struct perf_sample_data *data,
3426	struct perf_event *event)
3427	{
3428	u64 sample_type = event->attr.sample_type;
3429
3430	data->type = sample_type;
3431	header->size += event->id_header_size;
3432
3433	if (sample_type & PERF_SAMPLE_TID) {
3434	/* namespace issues */
3435	data->tid_entry.pid = perf_event_pid(event, current);
3436	data->tid_entry.tid = perf_event_tid(event, current);
3437	}
3438
3439	if (sample_type & PERF_SAMPLE_TIME)
3440	data->time = perf_clock();
3441
3442	if (sample_type & PERF_SAMPLE_ID)
3443	data->id = primary_event_id(event);
3444
3445	if (sample_type & PERF_SAMPLE_STREAM_ID)
3446	data->stream_id = event->id;
3447
3448	if (sample_type & PERF_SAMPLE_CPU) {
3449	data->cpu_entry.cpu = raw_smp_processor_id();
3450	data->cpu_entry.reserved = 0;
3451	}
3452	}
3453
3454	static void perf_event_header__init_id(struct perf_event_header *header,
3455	struct perf_sample_data *data,
3456	struct perf_event *event)
3457	{
3458	if (event->attr.sample_id_all)
3459	__perf_event_header__init_id(header, data, event);
3460	}
3461
3462	static void __perf_event__output_id_sample(struct perf_output_handle *handle,
3463	struct perf_sample_data *data)
3464	{
3465	u64 sample_type = data->type;
3466
3467	if (sample_type & PERF_SAMPLE_TID)
3468	perf_output_put(handle, data->tid_entry);
3469
3470	if (sample_type & PERF_SAMPLE_TIME)
3471	perf_output_put(handle, data->time);
3472
3473	if (sample_type & PERF_SAMPLE_ID)
3474	perf_output_put(handle, data->id);
3475
3476	if (sample_type & PERF_SAMPLE_STREAM_ID)
3477	perf_output_put(handle, data->stream_id);
3478
3479	if (sample_type & PERF_SAMPLE_CPU)
3480	perf_output_put(handle, data->cpu_entry);
3481	}
3482
3483	static void perf_event__output_id_sample(struct perf_event *event,
3484	struct perf_output_handle *handle,
3485	struct perf_sample_data *sample)
3486	{
3487	if (event->attr.sample_id_all)
3488	__perf_event__output_id_sample(handle, sample);
3489	}
3490
3491	int perf_output_begin(struct perf_output_handle *handle,
3492	struct perf_event *event, unsigned int size,
3493	int nmi, int sample)
3494	{
3495	struct perf_buffer *buffer;
3496	unsigned long tail, offset, head;
3497	int have_lost;
3498	struct perf_sample_data sample_data;
3499	struct {
3500	struct perf_event_header header;
3501	u64 id;
3502	u64 lost;
3503	} lost_event;
3504
3505	rcu_read_lock();
3506	/*
3507	* For inherited events we send all the output towards the parent.
3508	*/
3509	if (event->parent)
3510	event = event->parent;
3511
3512	buffer = rcu_dereference(event->buffer);
3513	if (!buffer)
3514	goto out;
3515
3516	handle->buffer = buffer;
3517	handle->event = event;
3518	handle->nmi = nmi;
3519	handle->sample = sample;
3520
3521	if (!buffer->nr_pages)
3522	goto out;
3523
3524	have_lost = local_read(&buffer->lost);
3525	if (have_lost) {
3526	lost_event.header.size = sizeof(lost_event);
3527	perf_event_header__init_id(&lost_event.header, &sample_data,
3528	event);
3529	size += lost_event.header.size;
3530	}
3531
3532	perf_output_get_handle(handle);
3533
3534	do {
3535	/*
3536	* Userspace could choose to issue a mb() before updating the
3537	* tail pointer. So that all reads will be completed before the
3538	* write is issued.
3539	*/
3540	tail = ACCESS_ONCE(buffer->user_page->data_tail);
3541	smp_rmb();
3542	offset = head = local_read(&buffer->head);
3543	head += size;
3544	if (unlikely(!perf_output_space(buffer, tail, offset, head)))
3545	goto fail;
3546	} while (local_cmpxchg(&buffer->head, offset, head) != offset);
3547
3548	if (head - local_read(&buffer->wakeup) > buffer->watermark)
3549	local_add(buffer->watermark, &buffer->wakeup);
3550
3551	handle->page = offset >> (PAGE_SHIFT + page_order(buffer));
3552	handle->page &= buffer->nr_pages - 1;
3553	handle->size = offset & ((PAGE_SIZE << page_order(buffer)) - 1);
3554	handle->addr = buffer->data_pages[handle->page];
3555	handle->addr += handle->size;
3556	handle->size = (PAGE_SIZE << page_order(buffer)) - handle->size;
3557
3558	if (have_lost) {
3559	lost_event.header.type = PERF_RECORD_LOST;
3560	lost_event.header.misc = 0;
3561	lost_event.id = event->id;
3562	lost_event.lost = local_xchg(&buffer->lost, 0);
3563
3564	perf_output_put(handle, lost_event);
3565	perf_event__output_id_sample(event, handle, &sample_data);
3566	}
3567
3568	return 0;
3569
3570	fail:
3571	local_inc(&buffer->lost);
3572	perf_output_put_handle(handle);
3573	out:
3574	rcu_read_unlock();
3575
3576	return -ENOSPC;
3577	}
3578
3579	void perf_output_end(struct perf_output_handle *handle)
3580	{
3581	struct perf_event *event = handle->event;
3582	struct perf_buffer *buffer = handle->buffer;
3583
3584	int wakeup_events = event->attr.wakeup_events;
3585
3586	if (handle->sample && wakeup_events) {
3587	int events = local_inc_return(&buffer->events);
3588	if (events >= wakeup_events) {
3589	local_sub(wakeup_events, &buffer->events);
3590	local_inc(&buffer->wakeup);
3591	}
3592	}
3593
3594	perf_output_put_handle(handle);
3595	rcu_read_unlock();
3596	}
3597
3598	static void perf_output_read_one(struct perf_output_handle *handle,
3599	struct perf_event *event,
3600	u64 enabled, u64 running)
3601	{
3602	u64 read_format = event->attr.read_format;
3603	u64 values[4];
3604	int n = 0;
3605
3606	values[n++] = perf_event_count(event);
3607	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3608	values[n++] = enabled +
3609	atomic64_read(&event->child_total_time_enabled);
3610	}
3611	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3612	values[n++] = running +
3613	atomic64_read(&event->child_total_time_running);
3614	}
3615	if (read_format & PERF_FORMAT_ID)
3616	values[n++] = primary_event_id(event);
3617
3618	perf_output_copy(handle, values, n * sizeof(u64));
3619	}
3620
3621	/*
3622	* XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
3623	*/
3624	static void perf_output_read_group(struct perf_output_handle *handle,
3625	struct perf_event *event,
3626	u64 enabled, u64 running)
3627	{
3628	struct perf_event leader = event->group_leader, sub;
3629	u64 read_format = event->attr.read_format;
3630	u64 values[5];
3631	int n = 0;
3632
3633	values[n++] = 1 + leader->nr_siblings;
3634
3635	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3636	values[n++] = enabled;
3637
3638	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3639	values[n++] = running;
3640
3641	if (leader != event)
3642	leader->pmu->read(leader);
3643
3644	values[n++] = perf_event_count(leader);
3645	if (read_format & PERF_FORMAT_ID)
3646	values[n++] = primary_event_id(leader);
3647
3648	perf_output_copy(handle, values, n * sizeof(u64));
3649
3650	list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3651	n = 0;
3652
3653	if (sub != event)
3654	sub->pmu->read(sub);
3655
3656	values[n++] = perf_event_count(sub);
3657	if (read_format & PERF_FORMAT_ID)
3658	values[n++] = primary_event_id(sub);
3659
3660	perf_output_copy(handle, values, n * sizeof(u64));
3661	}
3662	}
3663
3664	#define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED\|\
3665	PERF_FORMAT_TOTAL_TIME_RUNNING)
3666
3667	static void perf_output_read(struct perf_output_handle *handle,
3668	struct perf_event *event)
3669	{
3670	u64 enabled = 0, running = 0, now, ctx_time;
3671	u64 read_format = event->attr.read_format;
3672
3673	/*
3674	* compute total_time_enabled, total_time_running
3675	* based on snapshot values taken when the event
3676	* was last scheduled in.
3677	*
3678	* we cannot simply called update_context_time()
3679	* because of locking issue as we are called in
3680	* NMI context
3681	*/
3682	if (read_format & PERF_FORMAT_TOTAL_TIMES) {
3683	now = perf_clock();
3684	ctx_time = event->shadow_ctx_time + now;
3685	enabled = ctx_time - event->tstamp_enabled;
3686	running = ctx_time - event->tstamp_running;
3687	}
3688
3689	if (event->attr.read_format & PERF_FORMAT_GROUP)
3690	perf_output_read_group(handle, event, enabled, running);
3691	else
3692	perf_output_read_one(handle, event, enabled, running);
3693	}
3694
3695	void perf_output_sample(struct perf_output_handle *handle,
3696	struct perf_event_header *header,
3697	struct perf_sample_data *data,
3698	struct perf_event *event)
3699	{
3700	u64 sample_type = data->type;
3701
3702	perf_output_put(handle, *header);
3703
3704	if (sample_type & PERF_SAMPLE_IP)
3705	perf_output_put(handle, data->ip);
3706
3707	if (sample_type & PERF_SAMPLE_TID)
3708	perf_output_put(handle, data->tid_entry);
3709
3710	if (sample_type & PERF_SAMPLE_TIME)
3711	perf_output_put(handle, data->time);
3712
3713	if (sample_type & PERF_SAMPLE_ADDR)
3714	perf_output_put(handle, data->addr);
3715
3716	if (sample_type & PERF_SAMPLE_ID)
3717	perf_output_put(handle, data->id);
3718
3719	if (sample_type & PERF_SAMPLE_STREAM_ID)
3720	perf_output_put(handle, data->stream_id);
3721
3722	if (sample_type & PERF_SAMPLE_CPU)
3723	perf_output_put(handle, data->cpu_entry);
3724
3725	if (sample_type & PERF_SAMPLE_PERIOD)
3726	perf_output_put(handle, data->period);
3727
3728	if (sample_type & PERF_SAMPLE_READ)
3729	perf_output_read(handle, event);
3730
3731	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3732	if (data->callchain) {
3733	int size = 1;
3734
3735	if (data->callchain)
3736	size += data->callchain->nr;
3737
3738	size *= sizeof(u64);
3739
3740	perf_output_copy(handle, data->callchain, size);
3741	} else {
3742	u64 nr = 0;
3743	perf_output_put(handle, nr);
3744	}
3745	}
3746
3747	if (sample_type & PERF_SAMPLE_RAW) {
3748	if (data->raw) {
3749	perf_output_put(handle, data->raw->size);
3750	perf_output_copy(handle, data->raw->data,
3751	data->raw->size);
3752	} else {
3753	struct {
3754	u32 size;
3755	u32 data;
3756	} raw = {
3757	.size = sizeof(u32),
3758	.data = 0,
3759	};
3760	perf_output_put(handle, raw);
3761	}
3762	}
3763	}
3764
3765	void perf_prepare_sample(struct perf_event_header *header,
3766	struct perf_sample_data *data,
3767	struct perf_event *event,
3768	struct pt_regs *regs)
3769	{
3770	u64 sample_type = event->attr.sample_type;
3771
3772	header->type = PERF_RECORD_SAMPLE;
3773	header->size = sizeof(*header) + event->header_size;
3774
3775	header->misc = 0;
3776	header->misc \|= perf_misc_flags(regs);
3777
3778	__perf_event_header__init_id(header, data, event);
3779
3780	if (sample_type & PERF_SAMPLE_IP)
3781	data->ip = perf_instruction_pointer(regs);
3782
3783	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3784	int size = 1;
3785
3786	data->callchain = perf_callchain(regs);
3787
3788	if (data->callchain)
3789	size += data->callchain->nr;
3790
3791	header->size += size * sizeof(u64);
3792	}
3793
3794	if (sample_type & PERF_SAMPLE_RAW) {
3795	int size = sizeof(u32);
3796
3797	if (data->raw)
3798	size += data->raw->size;
3799	else
3800	size += sizeof(u32);
3801
3802	WARN_ON_ONCE(size & (sizeof(u64)-1));
3803	header->size += size;
3804	}
3805	}
3806
3807	static void perf_event_output(struct perf_event *event, int nmi,
3808	struct perf_sample_data *data,
3809	struct pt_regs *regs)
3810	{
3811	struct perf_output_handle handle;
3812	struct perf_event_header header;
3813
3814	/* protect the callchain buffers */
3815	rcu_read_lock();
3816
3817	perf_prepare_sample(&header, data, event, regs);
3818
3819	if (perf_output_begin(&handle, event, header.size, nmi, 1))
3820	goto exit;
3821
3822	perf_output_sample(&handle, &header, data, event);
3823
3824	perf_output_end(&handle);
3825
3826	exit:
3827	rcu_read_unlock();
3828	}
3829
3830	/*
3831	* read event_id
3832	*/
3833
3834	struct perf_read_event {
3835	struct perf_event_header header;
3836
3837	u32 pid;
3838	u32 tid;
3839	};
3840
3841	static void
3842	perf_event_read_event(struct perf_event *event,
3843	struct task_struct *task)
3844	{
3845	struct perf_output_handle handle;
3846	struct perf_sample_data sample;
3847	struct perf_read_event read_event = {
3848	.header = {
3849	.type = PERF_RECORD_READ,
3850	.misc = 0,
3851	.size = sizeof(read_event) + event->read_size,
3852	},
3853	.pid = perf_event_pid(event, task),
3854	.tid = perf_event_tid(event, task),
3855	};
3856	int ret;
3857
3858	perf_event_header__init_id(&read_event.header, &sample, event);
3859	ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0);
3860	if (ret)
3861	return;
3862
3863	perf_output_put(&handle, read_event);
3864	perf_output_read(&handle, event);
3865	perf_event__output_id_sample(event, &handle, &sample);
3866
3867	perf_output_end(&handle);
3868	}
3869
3870	/*
3871	* task tracking -- fork/exit
3872	*
3873	* enabled by: attr.comm \| attr.mmap \| attr.mmap_data \| attr.task
3874	*/
3875
3876	struct perf_task_event {
3877	struct task_struct *task;
3878	struct perf_event_context *task_ctx;
3879
3880	struct {
3881	struct perf_event_header header;
3882
3883	u32 pid;
3884	u32 ppid;
3885	u32 tid;
3886	u32 ptid;
3887	u64 time;
3888	} event_id;
3889	};
3890
3891	static void perf_event_task_output(struct perf_event *event,
3892	struct perf_task_event *task_event)
3893	{
3894	struct perf_output_handle handle;
3895	struct perf_sample_data sample;
3896	struct task_struct *task = task_event->task;
3897	int ret, size = task_event->event_id.header.size;
3898
3899	perf_event_header__init_id(&task_event->event_id.header, &sample, event);
3900
3901	ret = perf_output_begin(&handle, event,
3902	task_event->event_id.header.size, 0, 0);
3903	if (ret)
3904	goto out;
3905
3906	task_event->event_id.pid = perf_event_pid(event, task);
3907	task_event->event_id.ppid = perf_event_pid(event, current);
3908
3909	task_event->event_id.tid = perf_event_tid(event, task);
3910	task_event->event_id.ptid = perf_event_tid(event, current);
3911
3912	perf_output_put(&handle, task_event->event_id);
3913
3914	perf_event__output_id_sample(event, &handle, &sample);
3915
3916	perf_output_end(&handle);
3917	out:
3918	task_event->event_id.header.size = size;
3919	}
3920
3921	static int perf_event_task_match(struct perf_event *event)
3922	{
3923	if (event->state < PERF_EVENT_STATE_INACTIVE)
3924	return 0;
3925
3926	if (!event_filter_match(event))
3927	return 0;
3928
3929	if (event->attr.comm \|\| event->attr.mmap \|\|
3930	event->attr.mmap_data \|\| event->attr.task)
3931	return 1;
3932
3933	return 0;
3934	}
3935
3936	static void perf_event_task_ctx(struct perf_event_context *ctx,
3937	struct perf_task_event *task_event)
3938	{
3939	struct perf_event *event;
3940
3941	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3942	if (perf_event_task_match(event))
3943	perf_event_task_output(event, task_event);
3944	}
3945	}
3946
3947	static void perf_event_task_event(struct perf_task_event *task_event)
3948	{
3949	struct perf_cpu_context *cpuctx;
3950	struct perf_event_context *ctx;
3951	struct pmu *pmu;
3952	int ctxn;
3953
3954	rcu_read_lock();
3955	list_for_each_entry_rcu(pmu, &pmus, entry) {
3956	cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
3957	if (cpuctx->active_pmu != pmu)
3958	goto next;
3959	perf_event_task_ctx(&cpuctx->ctx, task_event);
3960
3961	ctx = task_event->task_ctx;
3962	if (!ctx) {
3963	ctxn = pmu->task_ctx_nr;
3964	if (ctxn < 0)
3965	goto next;
3966	ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
3967	}
3968	if (ctx)
3969	perf_event_task_ctx(ctx, task_event);
3970	next:
3971	put_cpu_ptr(pmu->pmu_cpu_context);
3972	}
3973	rcu_read_unlock();
3974	}
3975
3976	static void perf_event_task(struct task_struct *task,
3977	struct perf_event_context *task_ctx,
3978	int new)
3979	{
3980	struct perf_task_event task_event;
3981
3982	if (!atomic_read(&nr_comm_events) &&
3983	!atomic_read(&nr_mmap_events) &&
3984	!atomic_read(&nr_task_events))
3985	return;
3986
3987	task_event = (struct perf_task_event){
3988	.task = task,
3989	.task_ctx = task_ctx,
3990	.event_id = {
3991	.header = {
3992	.type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
3993	.misc = 0,
3994	.size = sizeof(task_event.event_id),
3995	},
3996	/* .pid */
3997	/* .ppid */
3998	/* .tid */
3999	/* .ptid */
4000	.time = perf_clock(),
4001	},
4002	};
4003
4004	perf_event_task_event(&task_event);
4005	}
4006
4007	void perf_event_fork(struct task_struct *task)
4008	{
4009	perf_event_task(task, NULL, 1);
4010	}
4011
4012	/*
4013	* comm tracking
4014	*/
4015
4016	struct perf_comm_event {
4017	struct task_struct *task;
4018	char *comm;
4019	int comm_size;
4020
4021	struct {
4022	struct perf_event_header header;
4023
4024	u32 pid;
4025	u32 tid;
4026	} event_id;
4027	};
4028
4029	static void perf_event_comm_output(struct perf_event *event,
4030	struct perf_comm_event *comm_event)
4031	{
4032	struct perf_output_handle handle;
4033	struct perf_sample_data sample;
4034	int size = comm_event->event_id.header.size;
4035	int ret;
4036
4037	perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
4038	ret = perf_output_begin(&handle, event,
4039	comm_event->event_id.header.size, 0, 0);
4040
4041	if (ret)
4042	goto out;
4043
4044	comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
4045	comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
4046
4047	perf_output_put(&handle, comm_event->event_id);
4048	perf_output_copy(&handle, comm_event->comm,
4049	comm_event->comm_size);
4050
4051	perf_event__output_id_sample(event, &handle, &sample);
4052
4053	perf_output_end(&handle);
4054	out:
4055	comm_event->event_id.header.size = size;
4056	}
4057
4058	static int perf_event_comm_match(struct perf_event *event)
4059	{
4060	if (event->state < PERF_EVENT_STATE_INACTIVE)
4061	return 0;
4062
4063	if (!event_filter_match(event))
4064	return 0;
4065
4066	if (event->attr.comm)
4067	return 1;
4068
4069	return 0;
4070	}
4071
4072	static void perf_event_comm_ctx(struct perf_event_context *ctx,
4073	struct perf_comm_event *comm_event)
4074	{
4075	struct perf_event *event;
4076
4077	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4078	if (perf_event_comm_match(event))
4079	perf_event_comm_output(event, comm_event);
4080	}
4081	}
4082
4083	static void perf_event_comm_event(struct perf_comm_event *comm_event)
4084	{
4085	struct perf_cpu_context *cpuctx;
4086	struct perf_event_context *ctx;
4087	char comm[TASK_COMM_LEN];
4088	unsigned int size;
4089	struct pmu *pmu;
4090	int ctxn;
4091
4092	memset(comm, 0, sizeof(comm));
4093	strlcpy(comm, comm_event->task->comm, sizeof(comm));
4094	size = ALIGN(strlen(comm)+1, sizeof(u64));
4095
4096	comm_event->comm = comm;
4097	comm_event->comm_size = size;
4098
4099	comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
4100	rcu_read_lock();
4101	list_for_each_entry_rcu(pmu, &pmus, entry) {
4102	cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
4103	if (cpuctx->active_pmu != pmu)
4104	goto next;
4105	perf_event_comm_ctx(&cpuctx->ctx, comm_event);
4106
4107	ctxn = pmu->task_ctx_nr;
4108	if (ctxn < 0)
4109	goto next;
4110
4111	ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
4112	if (ctx)
4113	perf_event_comm_ctx(ctx, comm_event);
4114	next:
4115	put_cpu_ptr(pmu->pmu_cpu_context);
4116	}
4117	rcu_read_unlock();
4118	}
4119
4120	void perf_event_comm(struct task_struct *task)
4121	{
4122	struct perf_comm_event comm_event;
4123	struct perf_event_context *ctx;
4124	int ctxn;
4125
4126	for_each_task_context_nr(ctxn) {
4127	ctx = task->perf_event_ctxp[ctxn];
4128	if (!ctx)
4129	continue;
4130
4131	perf_event_enable_on_exec(ctx);
4132	}
4133
4134	if (!atomic_read(&nr_comm_events))
4135	return;
4136
4137	comm_event = (struct perf_comm_event){
4138	.task = task,
4139	/* .comm */
4140	/* .comm_size */
4141	.event_id = {
4142	.header = {
4143	.type = PERF_RECORD_COMM,
4144	.misc = 0,
4145	/* .size */
4146	},
4147	/* .pid */
4148	/* .tid */
4149	},
4150	};
4151
4152	perf_event_comm_event(&comm_event);
4153	}
4154
4155	/*
4156	* mmap tracking
4157	*/
4158
4159	struct perf_mmap_event {
4160	struct vm_area_struct *vma;
4161
4162	const char *file_name;
4163	int file_size;
4164
4165	struct {
4166	struct perf_event_header header;
4167
4168	u32 pid;
4169	u32 tid;
4170	u64 start;
4171	u64 len;
4172	u64 pgoff;
4173	} event_id;
4174	};
4175
4176	static void perf_event_mmap_output(struct perf_event *event,
4177	struct perf_mmap_event *mmap_event)
4178	{
4179	struct perf_output_handle handle;
4180	struct perf_sample_data sample;
4181	int size = mmap_event->event_id.header.size;
4182	int ret;
4183
4184	perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
4185	ret = perf_output_begin(&handle, event,
4186	mmap_event->event_id.header.size, 0, 0);
4187	if (ret)
4188	goto out;
4189
4190	mmap_event->event_id.pid = perf_event_pid(event, current);
4191	mmap_event->event_id.tid = perf_event_tid(event, current);
4192
4193	perf_output_put(&handle, mmap_event->event_id);
4194	perf_output_copy(&handle, mmap_event->file_name,
4195	mmap_event->file_size);
4196
4197	perf_event__output_id_sample(event, &handle, &sample);
4198
4199	perf_output_end(&handle);
4200	out:
4201	mmap_event->event_id.header.size = size;
4202	}
4203
4204	static int perf_event_mmap_match(struct perf_event *event,
4205	struct perf_mmap_event *mmap_event,
4206	int executable)
4207	{
4208	if (event->state < PERF_EVENT_STATE_INACTIVE)
4209	return 0;
4210
4211	if (!event_filter_match(event))
4212	return 0;
4213
4214	if ((!executable && event->attr.mmap_data) \|\|
4215	(executable && event->attr.mmap))
4216	return 1;
4217
4218	return 0;
4219	}
4220
4221	static void perf_event_mmap_ctx(struct perf_event_context *ctx,
4222	struct perf_mmap_event *mmap_event,
4223	int executable)
4224	{
4225	struct perf_event *event;
4226
4227	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4228	if (perf_event_mmap_match(event, mmap_event, executable))
4229	perf_event_mmap_output(event, mmap_event);
4230	}
4231	}
4232
4233	static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
4234	{
4235	struct perf_cpu_context *cpuctx;
4236	struct perf_event_context *ctx;
4237	struct vm_area_struct *vma = mmap_event->vma;
4238	struct file *file = vma->vm_file;
4239	unsigned int size;
4240	char tmp[16];
4241	char *buf = NULL;
4242	const char *name;
4243	struct pmu *pmu;
4244	int ctxn;
4245
4246	memset(tmp, 0, sizeof(tmp));
4247
4248	if (file) {
4249	/*
4250	* d_path works from the end of the buffer backwards, so we
4251	* need to add enough zero bytes after the string to handle
4252	* the 64bit alignment we do later.
4253	*/
4254	buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
4255	if (!buf) {
4256	name = strncpy(tmp, "//enomem", sizeof(tmp));
4257	goto got_name;
4258	}
4259	name = d_path(&file->f_path, buf, PATH_MAX);
4260	if (IS_ERR(name)) {
4261	name = strncpy(tmp, "//toolong", sizeof(tmp));
4262	goto got_name;
4263	}
4264	} else {
4265	if (arch_vma_name(mmap_event->vma)) {
4266	name = strncpy(tmp, arch_vma_name(mmap_event->vma),
4267	sizeof(tmp));
4268	goto got_name;
4269	}
4270
4271	if (!vma->vm_mm) {
4272	name = strncpy(tmp, "[vdso]", sizeof(tmp));
4273	goto got_name;
4274	} else if (vma->vm_start <= vma->vm_mm->start_brk &&
4275	vma->vm_end >= vma->vm_mm->brk) {
4276	name = strncpy(tmp, "[heap]", sizeof(tmp));
4277	goto got_name;
4278	} else if (vma->vm_start <= vma->vm_mm->start_stack &&
4279	vma->vm_end >= vma->vm_mm->start_stack) {
4280	name = strncpy(tmp, "[stack]", sizeof(tmp));
4281	goto got_name;
4282	}
4283
4284	name = strncpy(tmp, "//anon", sizeof(tmp));
4285	goto got_name;
4286	}
4287
4288	got_name:
4289	size = ALIGN(strlen(name)+1, sizeof(u64));
4290
4291	mmap_event->file_name = name;
4292	mmap_event->file_size = size;
4293
4294	mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
4295
4296	rcu_read_lock();
4297	list_for_each_entry_rcu(pmu, &pmus, entry) {
4298	cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
4299	if (cpuctx->active_pmu != pmu)
4300	goto next;
4301	perf_event_mmap_ctx(&cpuctx->ctx, mmap_event,
4302	vma->vm_flags & VM_EXEC);
4303
4304	ctxn = pmu->task_ctx_nr;
4305	if (ctxn < 0)
4306	goto next;
4307
4308	ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
4309	if (ctx) {
4310	perf_event_mmap_ctx(ctx, mmap_event,
4311	vma->vm_flags & VM_EXEC);
4312	}
4313	next:
4314	put_cpu_ptr(pmu->pmu_cpu_context);
4315	}
4316	rcu_read_unlock();
4317
4318	kfree(buf);
4319	}
4320
4321	void perf_event_mmap(struct vm_area_struct *vma)
4322	{
4323	struct perf_mmap_event mmap_event;
4324
4325	if (!atomic_read(&nr_mmap_events))
4326	return;
4327
4328	mmap_event = (struct perf_mmap_event){
4329	.vma = vma,
4330	/* .file_name */
4331	/* .file_size */
4332	.event_id = {
4333	.header = {
4334	.type = PERF_RECORD_MMAP,
4335	.misc = PERF_RECORD_MISC_USER,
4336	/* .size */
4337	},
4338	/* .pid */
4339	/* .tid */
4340	.start = vma->vm_start,
4341	.len = vma->vm_end - vma->vm_start,
4342	.pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
4343	},
4344	};
4345
4346	perf_event_mmap_event(&mmap_event);
4347	}
4348
4349	/*
4350	* IRQ throttle logging
4351	*/
4352
4353	static void perf_log_throttle(struct perf_event *event, int enable)
4354	{
4355	struct perf_output_handle handle;
4356	struct perf_sample_data sample;
4357	int ret;
4358
4359	struct {
4360	struct perf_event_header header;
4361	u64 time;
4362	u64 id;
4363	u64 stream_id;
4364	} throttle_event = {
4365	.header = {
4366	.type = PERF_RECORD_THROTTLE,
4367	.misc = 0,
4368	.size = sizeof(throttle_event),
4369	},
4370	.time = perf_clock(),
4371	.id = primary_event_id(event),
4372	.stream_id = event->id,
4373	};
4374
4375	if (enable)
4376	throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
4377
4378	perf_event_header__init_id(&throttle_event.header, &sample, event);
4379
4380	ret = perf_output_begin(&handle, event,
4381	throttle_event.header.size, 1, 0);
4382	if (ret)
4383	return;
4384
4385	perf_output_put(&handle, throttle_event);
4386	perf_event__output_id_sample(event, &handle, &sample);
4387	perf_output_end(&handle);
4388	}
4389
4390	/*
4391	* Generic event overflow handling, sampling.
4392	*/
4393
4394	static int __perf_event_overflow(struct perf_event *event, int nmi,
4395	int throttle, struct perf_sample_data *data,
4396	struct pt_regs *regs)
4397	{
4398	int events = atomic_read(&event->event_limit);
4399	struct hw_perf_event *hwc = &event->hw;
4400	int ret = 0;
4401
4402	/*
4403	* Non-sampling counters might still use the PMI to fold short
4404	* hardware counters, ignore those.
4405	*/
4406	if (unlikely(!is_sampling_event(event)))
4407	return 0;
4408
4409	if (!throttle) {
4410	hwc->interrupts++;
4411	} else {
4412	if (hwc->interrupts != MAX_INTERRUPTS) {
4413	hwc->interrupts++;
4414	if (HZ * hwc->interrupts >
4415	(u64)sysctl_perf_event_sample_rate) {
4416	hwc->interrupts = MAX_INTERRUPTS;
4417	perf_log_throttle(event, 0);
4418	ret = 1;
4419	}
4420	} else {
4421	/*
4422	* Keep re-disabling events even though on the previous
4423	* pass we disabled it - just in case we raced with a
4424	* sched-in and the event got enabled again:
4425	*/
4426	ret = 1;
4427	}
4428	}
4429
4430	if (event->attr.freq) {
4431	u64 now = perf_clock();
4432	s64 delta = now - hwc->freq_time_stamp;
4433
4434	hwc->freq_time_stamp = now;
4435
4436	if (delta > 0 && delta < 2*TICK_NSEC)
4437	perf_adjust_period(event, delta, hwc->last_period);
4438	}
4439
4440	/*
4441	* XXX event_limit might not quite work as expected on inherited
4442	* events
4443	*/
4444
4445	event->pending_kill = POLL_IN;
4446	if (events && atomic_dec_and_test(&event->event_limit)) {
4447	ret = 1;
4448	event->pending_kill = POLL_HUP;
4449	if (nmi) {
4450	event->pending_disable = 1;
4451	irq_work_queue(&event->pending);
4452	} else
4453	perf_event_disable(event);
4454	}
4455
4456	if (event->overflow_handler)
4457	event->overflow_handler(event, nmi, data, regs);
4458	else
4459	perf_event_output(event, nmi, data, regs);
4460
4461	return ret;
4462	}
4463
4464	int perf_event_overflow(struct perf_event *event, int nmi,
4465	struct perf_sample_data *data,
4466	struct pt_regs *regs)
4467	{
4468	return __perf_event_overflow(event, nmi, 1, data, regs);
4469	}
4470
4471	/*
4472	* Generic software event infrastructure
4473	*/
4474
4475	struct swevent_htable {
4476	struct swevent_hlist *swevent_hlist;
4477	struct mutex hlist_mutex;
4478	int hlist_refcount;
4479
4480	/* Recursion avoidance in each contexts */
4481	int recursion[PERF_NR_CONTEXTS];
4482	};
4483
4484	static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
4485
4486	/*
4487	* We directly increment event->count and keep a second value in
4488	* event->hw.period_left to count intervals. This period event
4489	* is kept in the range [-sample_period, 0] so that we can use the
4490	* sign as trigger.
4491	*/
4492
4493	static u64 perf_swevent_set_period(struct perf_event *event)
4494	{
4495	struct hw_perf_event *hwc = &event->hw;
4496	u64 period = hwc->last_period;
4497	u64 nr, offset;
4498	s64 old, val;
4499
4500	hwc->last_period = hwc->sample_period;
4501
4502	again:
4503	old = val = local64_read(&hwc->period_left);
4504	if (val < 0)
4505	return 0;
4506
4507	nr = div64_u64(period + val, period);
4508	offset = nr * period;
4509	val -= offset;
4510	if (local64_cmpxchg(&hwc->period_left, old, val) != old)
4511	goto again;
4512
4513	return nr;
4514	}
4515
4516	static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
4517	int nmi, struct perf_sample_data *data,
4518	struct pt_regs *regs)
4519	{
4520	struct hw_perf_event *hwc = &event->hw;
4521	int throttle = 0;
4522
4523	data->period = event->hw.last_period;
4524	if (!overflow)
4525	overflow = perf_swevent_set_period(event);
4526
4527	if (hwc->interrupts == MAX_INTERRUPTS)
4528	return;
4529
4530	for (; overflow; overflow--) {
4531	if (__perf_event_overflow(event, nmi, throttle,
4532	data, regs)) {
4533	/*
4534	* We inhibit the overflow from happening when
4535	* hwc->interrupts == MAX_INTERRUPTS.
4536	*/
4537	break;
4538	}
4539	throttle = 1;
4540	}
4541	}
4542
4543	static void perf_swevent_event(struct perf_event *event, u64 nr,
4544	int nmi, struct perf_sample_data *data,
4545	struct pt_regs *regs)
4546	{
4547	struct hw_perf_event *hwc = &event->hw;
4548
4549	local64_add(nr, &event->count);
4550
4551	if (!regs)
4552	return;
4553
4554	if (!is_sampling_event(event))
4555	return;
4556
4557	if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
4558	return perf_swevent_overflow(event, 1, nmi, data, regs);
4559
4560	if (local64_add_negative(nr, &hwc->period_left))
4561	return;
4562
4563	perf_swevent_overflow(event, 0, nmi, data, regs);
4564	}
4565
4566	static int perf_exclude_event(struct perf_event *event,
4567	struct pt_regs *regs)
4568	{
4569	if (event->hw.state & PERF_HES_STOPPED)
4570	return 0;
4571
4572	if (regs) {
4573	if (event->attr.exclude_user && user_mode(regs))
4574	return 1;
4575
4576	if (event->attr.exclude_kernel && !user_mode(regs))
4577	return 1;
4578	}
4579
4580	return 0;
4581	}
4582
4583	static int perf_swevent_match(struct perf_event *event,
4584	enum perf_type_id type,
4585	u32 event_id,
4586	struct perf_sample_data *data,
4587	struct pt_regs *regs)
4588	{
4589	if (event->attr.type != type)
4590	return 0;
4591
4592	if (event->attr.config != event_id)
4593	return 0;
4594
4595	if (perf_exclude_event(event, regs))
4596	return 0;
4597
4598	return 1;
4599	}
4600
4601	static inline u64 swevent_hash(u64 type, u32 event_id)
4602	{
4603	u64 val = event_id \| (type << 32);
4604
4605	return hash_64(val, SWEVENT_HLIST_BITS);
4606	}
4607
4608	static inline struct hlist_head *
4609	__find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
4610	{
4611	u64 hash = swevent_hash(type, event_id);
4612
4613	return &hlist->heads[hash];
4614	}
4615
4616	/* For the read side: events when they trigger */
4617	static inline struct hlist_head *
4618	find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
4619	{
4620	struct swevent_hlist *hlist;
4621
4622	hlist = rcu_dereference(swhash->swevent_hlist);
4623	if (!hlist)
4624	return NULL;
4625
4626	return __find_swevent_head(hlist, type, event_id);
4627	}
4628
4629	/* For the event head insertion and removal in the hlist */
4630	static inline struct hlist_head *
4631	find_swevent_head(struct swevent_htable swhash, struct perf_event event)
4632	{
4633	struct swevent_hlist *hlist;
4634	u32 event_id = event->attr.config;
4635	u64 type = event->attr.type;
4636
4637	/*
4638	* Event scheduling is always serialized against hlist allocation
4639	* and release. Which makes the protected version suitable here.
4640	* The context lock guarantees that.
4641	*/
4642	hlist = rcu_dereference_protected(swhash->swevent_hlist,
4643	lockdep_is_held(&event->ctx->lock));
4644	if (!hlist)
4645	return NULL;
4646
4647	return __find_swevent_head(hlist, type, event_id);
4648	}
4649
4650	static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
4651	u64 nr, int nmi,
4652	struct perf_sample_data *data,
4653	struct pt_regs *regs)
4654	{
4655	struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
4656	struct perf_event *event;
4657	struct hlist_node *node;
4658	struct hlist_head *head;
4659
4660	rcu_read_lock();
4661	head = find_swevent_head_rcu(swhash, type, event_id);
4662	if (!head)
4663	goto end;
4664
4665	hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
4666	if (perf_swevent_match(event, type, event_id, data, regs))
4667	perf_swevent_event(event, nr, nmi, data, regs);
4668	}
4669	end:
4670	rcu_read_unlock();
4671	}
4672
4673	int perf_swevent_get_recursion_context(void)
4674	{
4675	struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
4676
4677	return get_recursion_context(swhash->recursion);
4678	}
4679	EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
4680
4681	inline void perf_swevent_put_recursion_context(int rctx)
4682	{
4683	struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
4684
4685	put_recursion_context(swhash->recursion, rctx);
4686	}
4687
4688	void __perf_sw_event(u32 event_id, u64 nr, int nmi,
4689	struct pt_regs *regs, u64 addr)
4690	{
4691	struct perf_sample_data data;
4692	int rctx;
4693
4694	preempt_disable_notrace();
4695	rctx = perf_swevent_get_recursion_context();
4696	if (rctx < 0)
4697	return;
4698
4699	perf_sample_data_init(&data, addr);
4700
4701	do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs);
4702
4703	perf_swevent_put_recursion_context(rctx);
4704	preempt_enable_notrace();
4705	}
4706
4707	static void perf_swevent_read(struct perf_event *event)
4708	{
4709	}
4710
4711	static int perf_swevent_add(struct perf_event *event, int flags)
4712	{
4713	struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
4714	struct hw_perf_event *hwc = &event->hw;
4715	struct hlist_head *head;
4716
4717	if (is_sampling_event(event)) {
4718	hwc->last_period = hwc->sample_period;
4719	perf_swevent_set_period(event);
4720	}
4721
4722	hwc->state = !(flags & PERF_EF_START);
4723
4724	head = find_swevent_head(swhash, event);
4725	if (WARN_ON_ONCE(!head))
4726	return -EINVAL;
4727
4728	hlist_add_head_rcu(&event->hlist_entry, head);
4729
4730	return 0;
4731	}
4732
4733	static void perf_swevent_del(struct perf_event *event, int flags)
4734	{
4735	hlist_del_rcu(&event->hlist_entry);
4736	}
4737
4738	static void perf_swevent_start(struct perf_event *event, int flags)
4739	{
4740	event->hw.state = 0;
4741	}
4742
4743	static void perf_swevent_stop(struct perf_event *event, int flags)
4744	{
4745	event->hw.state = PERF_HES_STOPPED;
4746	}
4747
4748	/* Deref the hlist from the update side */
4749	static inline struct swevent_hlist *
4750	swevent_hlist_deref(struct swevent_htable *swhash)
4751	{
4752	return rcu_dereference_protected(swhash->swevent_hlist,
4753	lockdep_is_held(&swhash->hlist_mutex));
4754	}
4755
4756	static void swevent_hlist_release_rcu(struct rcu_head *rcu_head)
4757	{
4758	struct swevent_hlist *hlist;
4759
4760	hlist = container_of(rcu_head, struct swevent_hlist, rcu_head);
4761	kfree(hlist);
4762	}
4763
4764	static void swevent_hlist_release(struct swevent_htable *swhash)
4765	{
4766	struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
4767
4768	if (!hlist)
4769	return;
4770
4771	rcu_assign_pointer(swhash->swevent_hlist, NULL);
4772	call_rcu(&hlist->rcu_head, swevent_hlist_release_rcu);
4773	}
4774
4775	static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
4776	{
4777	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
4778
4779	mutex_lock(&swhash->hlist_mutex);
4780
4781	if (!--swhash->hlist_refcount)
4782	swevent_hlist_release(swhash);
4783
4784	mutex_unlock(&swhash->hlist_mutex);
4785	}
4786
4787	static void swevent_hlist_put(struct perf_event *event)
4788	{
4789	int cpu;
4790
4791	if (event->cpu != -1) {
4792	swevent_hlist_put_cpu(event, event->cpu);
4793	return;
4794	}
4795
4796	for_each_possible_cpu(cpu)
4797	swevent_hlist_put_cpu(event, cpu);
4798	}
4799
4800	static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
4801	{
4802	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
4803	int err = 0;
4804
4805	mutex_lock(&swhash->hlist_mutex);
4806
4807	if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
4808	struct swevent_hlist *hlist;
4809
4810	hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
4811	if (!hlist) {
4812	err = -ENOMEM;
4813	goto exit;
4814	}
4815	rcu_assign_pointer(swhash->swevent_hlist, hlist);
4816	}
4817	swhash->hlist_refcount++;
4818	exit:
4819	mutex_unlock(&swhash->hlist_mutex);
4820
4821	return err;
4822	}
4823
4824	static int swevent_hlist_get(struct perf_event *event)
4825	{
4826	int err;
4827	int cpu, failed_cpu;
4828
4829	if (event->cpu != -1)
4830	return swevent_hlist_get_cpu(event, event->cpu);
4831
4832	get_online_cpus();
4833	for_each_possible_cpu(cpu) {
4834	err = swevent_hlist_get_cpu(event, cpu);
4835	if (err) {
4836	failed_cpu = cpu;
4837	goto fail;
4838	}
4839	}
4840	put_online_cpus();
4841
4842	return 0;
4843	fail:
4844	for_each_possible_cpu(cpu) {
4845	if (cpu == failed_cpu)
4846	break;
4847	swevent_hlist_put_cpu(event, cpu);
4848	}
4849
4850	put_online_cpus();
4851	return err;
4852	}
4853
4854	atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX];
4855
4856	static void sw_perf_event_destroy(struct perf_event *event)
4857	{
4858	u64 event_id = event->attr.config;
4859
4860	WARN_ON(event->parent);
4861
4862	jump_label_dec(&perf_swevent_enabled[event_id]);
4863	swevent_hlist_put(event);
4864	}
4865
4866	static int perf_swevent_init(struct perf_event *event)
4867	{
4868	int event_id = event->attr.config;
4869
4870	if (event->attr.type != PERF_TYPE_SOFTWARE)
4871	return -ENOENT;
4872
4873	switch (event_id) {
4874	case PERF_COUNT_SW_CPU_CLOCK:
4875	case PERF_COUNT_SW_TASK_CLOCK:
4876	return -ENOENT;
4877
4878	default:
4879	break;
4880	}
4881
4882	if (event_id >= PERF_COUNT_SW_MAX)
4883	return -ENOENT;
4884
4885	if (!event->parent) {
4886	int err;
4887
4888	err = swevent_hlist_get(event);
4889	if (err)
4890	return err;
4891
4892	jump_label_inc(&perf_swevent_enabled[event_id]);
4893	event->destroy = sw_perf_event_destroy;
4894	}
4895
4896	return 0;
4897	}
4898
4899	static struct pmu perf_swevent = {
4900	.task_ctx_nr = perf_sw_context,
4901
4902	.event_init = perf_swevent_init,
4903	.add = perf_swevent_add,
4904	.del = perf_swevent_del,
4905	.start = perf_swevent_start,
4906	.stop = perf_swevent_stop,
4907	.read = perf_swevent_read,
4908	};
4909
4910	#ifdef CONFIG_EVENT_TRACING
4911
4912	static int perf_tp_filter_match(struct perf_event *event,
4913	struct perf_sample_data *data)
4914	{
4915	void *record = data->raw->data;
4916
4917	if (likely(!event->filter) \|\| filter_match_preds(event->filter, record))
4918	return 1;
4919	return 0;
4920	}
4921
4922	static int perf_tp_event_match(struct perf_event *event,
4923	struct perf_sample_data *data,
4924	struct pt_regs *regs)
4925	{
4926	/*
4927	* All tracepoints are from kernel-space.
4928	*/
4929	if (event->attr.exclude_kernel)
4930	return 0;
4931
4932	if (!perf_tp_filter_match(event, data))
4933	return 0;
4934
4935	return 1;
4936	}
4937
4938	void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
4939	struct pt_regs regs, struct hlist_head head, int rctx)
4940	{
4941	struct perf_sample_data data;
4942	struct perf_event *event;
4943	struct hlist_node *node;
4944
4945	struct perf_raw_record raw = {
4946	.size = entry_size,
4947	.data = record,
4948	};
4949
4950	perf_sample_data_init(&data, addr);
4951	data.raw = &raw;
4952
4953	hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
4954	if (perf_tp_event_match(event, &data, regs))
4955	perf_swevent_event(event, count, 1, &data, regs);
4956	}
4957
4958	perf_swevent_put_recursion_context(rctx);
4959	}
4960	EXPORT_SYMBOL_GPL(perf_tp_event);
4961
4962	static void tp_perf_event_destroy(struct perf_event *event)
4963	{
4964	perf_trace_destroy(event);
4965	}
4966
4967	static int perf_tp_event_init(struct perf_event *event)
4968	{
4969	int err;
4970
4971	if (event->attr.type != PERF_TYPE_TRACEPOINT)
4972	return -ENOENT;
4973
4974	err = perf_trace_init(event);
4975	if (err)
4976	return err;
4977
4978	event->destroy = tp_perf_event_destroy;
4979
4980	return 0;
4981	}
4982
4983	static struct pmu perf_tracepoint = {
4984	.task_ctx_nr = perf_sw_context,
4985
4986	.event_init = perf_tp_event_init,
4987	.add = perf_trace_add,
4988	.del = perf_trace_del,
4989	.start = perf_swevent_start,
4990	.stop = perf_swevent_stop,
4991	.read = perf_swevent_read,
4992	};
4993
4994	static inline void perf_tp_register(void)
4995	{
4996	perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
4997	}
4998
4999	static int perf_event_set_filter(struct perf_event event, void __user arg)
5000	{
5001	char *filter_str;
5002	int ret;
5003
5004	if (event->attr.type != PERF_TYPE_TRACEPOINT)
5005	return -EINVAL;
5006
5007	filter_str = strndup_user(arg, PAGE_SIZE);
5008	if (IS_ERR(filter_str))
5009	return PTR_ERR(filter_str);
5010
5011	ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
5012
5013	kfree(filter_str);
5014	return ret;
5015	}
5016
5017	static void perf_event_free_filter(struct perf_event *event)
5018	{
5019	ftrace_profile_free_filter(event);
5020	}
5021
5022	#else
5023
5024	static inline void perf_tp_register(void)
5025	{
5026	}
5027
5028	static int perf_event_set_filter(struct perf_event event, void __user arg)
5029	{
5030	return -ENOENT;
5031	}
5032
5033	static void perf_event_free_filter(struct perf_event *event)
5034	{
5035	}
5036
5037	#endif /* CONFIG_EVENT_TRACING */
5038
5039	#ifdef CONFIG_HAVE_HW_BREAKPOINT
5040	void perf_bp_event(struct perf_event bp, void data)
5041	{
5042	struct perf_sample_data sample;
5043	struct pt_regs *regs = data;
5044
5045	perf_sample_data_init(&sample, bp->attr.bp_addr);
5046
5047	if (!bp->hw.state && !perf_exclude_event(bp, regs))
5048	perf_swevent_event(bp, 1, 1, &sample, regs);
5049	}
5050	#endif
5051
5052	/*
5053	* hrtimer based swevent callback
5054	*/
5055
5056	static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
5057	{
5058	enum hrtimer_restart ret = HRTIMER_RESTART;
5059	struct perf_sample_data data;
5060	struct pt_regs *regs;
5061	struct perf_event *event;
5062	u64 period;
5063
5064	event = container_of(hrtimer, struct perf_event, hw.hrtimer);
5065	event->pmu->read(event);
5066
5067	perf_sample_data_init(&data, 0);
5068	data.period = event->hw.last_period;
5069	regs = get_irq_regs();
5070
5071	if (regs && !perf_exclude_event(event, regs)) {
5072	if (!(event->attr.exclude_idle && current->pid == 0))
5073	if (perf_event_overflow(event, 0, &data, regs))
5074	ret = HRTIMER_NORESTART;
5075	}
5076
5077	period = max_t(u64, 10000, event->hw.sample_period);
5078	hrtimer_forward_now(hrtimer, ns_to_ktime(period));
5079
5080	return ret;
5081	}
5082
5083	static void perf_swevent_start_hrtimer(struct perf_event *event)
5084	{
5085	struct hw_perf_event *hwc = &event->hw;
5086	s64 period;
5087
5088	if (!is_sampling_event(event))
5089	return;
5090
5091	hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
5092	hwc->hrtimer.function = perf_swevent_hrtimer;
5093
5094	period = local64_read(&hwc->period_left);
5095	if (period) {
5096	if (period < 0)
5097	period = 10000;
5098
5099	local64_set(&hwc->period_left, 0);
5100	} else {
5101	period = max_t(u64, 10000, hwc->sample_period);
5102	}
5103	__hrtimer_start_range_ns(&hwc->hrtimer,
5104	ns_to_ktime(period), 0,
5105	HRTIMER_MODE_REL_PINNED, 0);
5106	}
5107
5108	static void perf_swevent_cancel_hrtimer(struct perf_event *event)
5109	{
5110	struct hw_perf_event *hwc = &event->hw;
5111
5112	if (is_sampling_event(event)) {
5113	ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
5114	local64_set(&hwc->period_left, ktime_to_ns(remaining));
5115
5116	hrtimer_cancel(&hwc->hrtimer);
5117	}
5118	}
5119
5120	/*
5121	* Software event: cpu wall time clock
5122	*/
5123
5124	static void cpu_clock_event_update(struct perf_event *event)
5125	{
5126	s64 prev;
5127	u64 now;
5128
5129	now = local_clock();
5130	prev = local64_xchg(&event->hw.prev_count, now);
5131	local64_add(now - prev, &event->count);
5132	}
5133
5134	static void cpu_clock_event_start(struct perf_event *event, int flags)
5135	{
5136	local64_set(&event->hw.prev_count, local_clock());
5137	perf_swevent_start_hrtimer(event);
5138	}
5139
5140	static void cpu_clock_event_stop(struct perf_event *event, int flags)
5141	{
5142	perf_swevent_cancel_hrtimer(event);
5143	cpu_clock_event_update(event);
5144	}
5145
5146	static int cpu_clock_event_add(struct perf_event *event, int flags)
5147	{
5148	if (flags & PERF_EF_START)
5149	cpu_clock_event_start(event, flags);
5150
5151	return 0;
5152	}
5153
5154	static void cpu_clock_event_del(struct perf_event *event, int flags)
5155	{
5156	cpu_clock_event_stop(event, flags);
5157	}
5158
5159	static void cpu_clock_event_read(struct perf_event *event)
5160	{
5161	cpu_clock_event_update(event);
5162	}
5163
5164	static int cpu_clock_event_init(struct perf_event *event)
5165	{
5166	if (event->attr.type != PERF_TYPE_SOFTWARE)
5167	return -ENOENT;
5168
5169	if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
5170	return -ENOENT;
5171
5172	return 0;
5173	}
5174
5175	static struct pmu perf_cpu_clock = {
5176	.task_ctx_nr = perf_sw_context,
5177
5178	.event_init = cpu_clock_event_init,
5179	.add = cpu_clock_event_add,
5180	.del = cpu_clock_event_del,
5181	.start = cpu_clock_event_start,
5182	.stop = cpu_clock_event_stop,
5183	.read = cpu_clock_event_read,
5184	};
5185
5186	/*
5187	* Software event: task time clock
5188	*/
5189
5190	static void task_clock_event_update(struct perf_event *event, u64 now)
5191	{
5192	u64 prev;
5193	s64 delta;
5194
5195	prev = local64_xchg(&event->hw.prev_count, now);
5196	delta = now - prev;
5197	local64_add(delta, &event->count);
5198	}
5199
5200	static void task_clock_event_start(struct perf_event *event, int flags)
5201	{
5202	local64_set(&event->hw.prev_count, event->ctx->time);
5203	perf_swevent_start_hrtimer(event);
5204	}
5205
5206	static void task_clock_event_stop(struct perf_event *event, int flags)
5207	{
5208	perf_swevent_cancel_hrtimer(event);
5209	task_clock_event_update(event, event->ctx->time);
5210	}
5211
5212	static int task_clock_event_add(struct perf_event *event, int flags)
5213	{
5214	if (flags & PERF_EF_START)
5215	task_clock_event_start(event, flags);
5216
5217	return 0;
5218	}
5219
5220	static void task_clock_event_del(struct perf_event *event, int flags)
5221	{
5222	task_clock_event_stop(event, PERF_EF_UPDATE);
5223	}
5224
5225	static void task_clock_event_read(struct perf_event *event)
5226	{
5227	u64 time;
5228
5229	if (!in_nmi()) {
5230	update_context_time(event->ctx);
5231	time = event->ctx->time;
5232	} else {
5233	u64 now = perf_clock();
5234	u64 delta = now - event->ctx->timestamp;
5235	time = event->ctx->time + delta;
5236	}
5237
5238	task_clock_event_update(event, time);
5239	}
5240
5241	static int task_clock_event_init(struct perf_event *event)
5242	{
5243	if (event->attr.type != PERF_TYPE_SOFTWARE)
5244	return -ENOENT;
5245
5246	if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
5247	return -ENOENT;
5248
5249	return 0;
5250	}
5251
5252	static struct pmu perf_task_clock = {
5253	.task_ctx_nr = perf_sw_context,
5254
5255	.event_init = task_clock_event_init,
5256	.add = task_clock_event_add,
5257	.del = task_clock_event_del,
5258	.start = task_clock_event_start,
5259	.stop = task_clock_event_stop,
5260	.read = task_clock_event_read,
5261	};
5262
5263	static void perf_pmu_nop_void(struct pmu *pmu)
5264	{
5265	}
5266
5267	static int perf_pmu_nop_int(struct pmu *pmu)
5268	{
5269	return 0;
5270	}
5271
5272	static void perf_pmu_start_txn(struct pmu *pmu)
5273	{
5274	perf_pmu_disable(pmu);
5275	}
5276
5277	static int perf_pmu_commit_txn(struct pmu *pmu)
5278	{
5279	perf_pmu_enable(pmu);
5280	return 0;
5281	}
5282
5283	static void perf_pmu_cancel_txn(struct pmu *pmu)
5284	{
5285	perf_pmu_enable(pmu);
5286	}
5287
5288	/*
5289	* Ensures all contexts with the same task_ctx_nr have the same
5290	* pmu_cpu_context too.
5291	*/
5292	static void *find_pmu_context(int ctxn)
5293	{
5294	struct pmu *pmu;
5295
5296	if (ctxn < 0)
5297	return NULL;
5298
5299	list_for_each_entry(pmu, &pmus, entry) {
5300	if (pmu->task_ctx_nr == ctxn)
5301	return pmu->pmu_cpu_context;
5302	}
5303
5304	return NULL;
5305	}
5306
5307	static void update_pmu_context(struct pmu pmu, struct pmu old_pmu)
5308	{
5309	int cpu;
5310
5311	for_each_possible_cpu(cpu) {
5312	struct perf_cpu_context *cpuctx;
5313
5314	cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
5315
5316	if (cpuctx->active_pmu == old_pmu)
5317	cpuctx->active_pmu = pmu;
5318	}
5319	}
5320
5321	static void free_pmu_context(struct pmu *pmu)
5322	{
5323	struct pmu *i;
5324
5325	mutex_lock(&pmus_lock);
5326	/*
5327	* Like a real lame refcount.
5328	*/
5329	list_for_each_entry(i, &pmus, entry) {
5330	if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
5331	update_pmu_context(i, pmu);
5332	goto out;
5333	}
5334	}
5335
5336	free_percpu(pmu->pmu_cpu_context);
5337	out:
5338	mutex_unlock(&pmus_lock);
5339	}
5340	static struct idr pmu_idr;
5341
5342	static ssize_t
5343	type_show(struct device dev, struct device_attribute attr, char *page)
5344	{
5345	struct pmu *pmu = dev_get_drvdata(dev);
5346
5347	return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
5348	}
5349
5350	static struct device_attribute pmu_dev_attrs[] = {
5351	__ATTR_RO(type),
5352	__ATTR_NULL,
5353	};
5354
5355	static int pmu_bus_running;
5356	static struct bus_type pmu_bus = {
5357	.name = "event_source",
5358	.dev_attrs = pmu_dev_attrs,
5359	};
5360
5361	static void pmu_dev_release(struct device *dev)
5362	{
5363	kfree(dev);
5364	}
5365
5366	static int pmu_dev_alloc(struct pmu *pmu)
5367	{
5368	int ret = -ENOMEM;
5369
5370	pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
5371	if (!pmu->dev)
5372	goto out;
5373
5374	device_initialize(pmu->dev);
5375	ret = dev_set_name(pmu->dev, "%s", pmu->name);
5376	if (ret)
5377	goto free_dev;
5378
5379	dev_set_drvdata(pmu->dev, pmu);
5380	pmu->dev->bus = &pmu_bus;
5381	pmu->dev->release = pmu_dev_release;
5382	ret = device_add(pmu->dev);
5383	if (ret)
5384	goto free_dev;
5385
5386	out:
5387	return ret;
5388
5389	free_dev:
5390	put_device(pmu->dev);
5391	goto out;
5392	}
5393
5394	static struct lock_class_key cpuctx_mutex;
5395
5396	int perf_pmu_register(struct pmu pmu, char name, int type)
5397	{
5398	int cpu, ret;
5399
5400	mutex_lock(&pmus_lock);
5401	ret = -ENOMEM;
5402	pmu->pmu_disable_count = alloc_percpu(int);
5403	if (!pmu->pmu_disable_count)
5404	goto unlock;
5405
5406	pmu->type = -1;
5407	if (!name)
5408	goto skip_type;
5409	pmu->name = name;
5410
5411	if (type < 0) {
5412	int err = idr_pre_get(&pmu_idr, GFP_KERNEL);
5413	if (!err)
5414	goto free_pdc;
5415
5416	err = idr_get_new_above(&pmu_idr, pmu, PERF_TYPE_MAX, &type);
5417	if (err) {
5418	ret = err;
5419	goto free_pdc;
5420	}
5421	}
5422	pmu->type = type;
5423
5424	if (pmu_bus_running) {
5425	ret = pmu_dev_alloc(pmu);
5426	if (ret)
5427	goto free_idr;
5428	}
5429
5430	skip_type:
5431	pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
5432	if (pmu->pmu_cpu_context)
5433	goto got_cpu_context;
5434
5435	pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
5436	if (!pmu->pmu_cpu_context)
5437	goto free_dev;
5438
5439	for_each_possible_cpu(cpu) {
5440	struct perf_cpu_context *cpuctx;
5441
5442	cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
5443	__perf_event_init_context(&cpuctx->ctx);
5444	lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
5445	cpuctx->ctx.type = cpu_context;
5446	cpuctx->ctx.pmu = pmu;
5447	cpuctx->jiffies_interval = 1;
5448	INIT_LIST_HEAD(&cpuctx->rotation_list);
5449	cpuctx->active_pmu = pmu;
5450	}
5451
5452	got_cpu_context:
5453	if (!pmu->start_txn) {
5454	if (pmu->pmu_enable) {
5455	/*
5456	* If we have pmu_enable/pmu_disable calls, install
5457	* transaction stubs that use that to try and batch
5458	* hardware accesses.
5459	*/
5460	pmu->start_txn = perf_pmu_start_txn;
5461	pmu->commit_txn = perf_pmu_commit_txn;
5462	pmu->cancel_txn = perf_pmu_cancel_txn;
5463	} else {
5464	pmu->start_txn = perf_pmu_nop_void;
5465	pmu->commit_txn = perf_pmu_nop_int;
5466	pmu->cancel_txn = perf_pmu_nop_void;
5467	}
5468	}
5469
5470	if (!pmu->pmu_enable) {
5471	pmu->pmu_enable = perf_pmu_nop_void;
5472	pmu->pmu_disable = perf_pmu_nop_void;
5473	}
5474
5475	list_add_rcu(&pmu->entry, &pmus);
5476	ret = 0;
5477	unlock:
5478	mutex_unlock(&pmus_lock);
5479
5480	return ret;
5481
5482	free_dev:
5483	device_del(pmu->dev);
5484	put_device(pmu->dev);
5485
5486	free_idr:
5487	if (pmu->type >= PERF_TYPE_MAX)
5488	idr_remove(&pmu_idr, pmu->type);
5489
5490	free_pdc:
5491	free_percpu(pmu->pmu_disable_count);
5492	goto unlock;
5493	}
5494
5495	void perf_pmu_unregister(struct pmu *pmu)
5496	{
5497	mutex_lock(&pmus_lock);
5498	list_del_rcu(&pmu->entry);
5499	mutex_unlock(&pmus_lock);
5500
5501	/*
5502	* We dereference the pmu list under both SRCU and regular RCU, so
5503	* synchronize against both of those.
5504	*/
5505	synchronize_srcu(&pmus_srcu);
5506	synchronize_rcu();
5507
5508	free_percpu(pmu->pmu_disable_count);
5509	if (pmu->type >= PERF_TYPE_MAX)
5510	idr_remove(&pmu_idr, pmu->type);
5511	device_del(pmu->dev);
5512	put_device(pmu->dev);
5513	free_pmu_context(pmu);
5514	}
5515
5516	struct pmu perf_init_event(struct perf_event event)
5517	{
5518	struct pmu *pmu = NULL;
5519	int idx;
5520
5521	idx = srcu_read_lock(&pmus_srcu);
5522
5523	rcu_read_lock();
5524	pmu = idr_find(&pmu_idr, event->attr.type);
5525	rcu_read_unlock();
5526	if (pmu)
5527	goto unlock;
5528
5529	list_for_each_entry_rcu(pmu, &pmus, entry) {
5530	int ret = pmu->event_init(event);
5531	if (!ret)
5532	goto unlock;
5533
5534	if (ret != -ENOENT) {
5535	pmu = ERR_PTR(ret);
5536	goto unlock;
5537	}
5538	}
5539	pmu = ERR_PTR(-ENOENT);
5540	unlock:
5541	srcu_read_unlock(&pmus_srcu, idx);
5542
5543	return pmu;
5544	}
5545
5546	/*
5547	* Allocate and initialize a event structure
5548	*/
5549	static struct perf_event *
5550	perf_event_alloc(struct perf_event_attr *attr, int cpu,
5551	struct task_struct *task,
5552	struct perf_event *group_leader,
5553	struct perf_event *parent_event,
5554	perf_overflow_handler_t overflow_handler)
5555	{
5556	struct pmu *pmu;
5557	struct perf_event *event;
5558	struct hw_perf_event *hwc;
5559	long err;
5560
5561	if ((unsigned)cpu >= nr_cpu_ids) {
5562	if (!task \|\| cpu != -1)
5563	return ERR_PTR(-EINVAL);
5564	}
5565
5566	event = kzalloc(sizeof(*event), GFP_KERNEL);
5567	if (!event)
5568	return ERR_PTR(-ENOMEM);
5569
5570	/*
5571	* Single events are their own group leaders, with an
5572	* empty sibling list:
5573	*/
5574	if (!group_leader)
5575	group_leader = event;
5576
5577	mutex_init(&event->child_mutex);
5578	INIT_LIST_HEAD(&event->child_list);
5579
5580	INIT_LIST_HEAD(&event->group_entry);
5581	INIT_LIST_HEAD(&event->event_entry);
5582	INIT_LIST_HEAD(&event->sibling_list);
5583	init_waitqueue_head(&event->waitq);
5584	init_irq_work(&event->pending, perf_pending_event);
5585
5586	mutex_init(&event->mmap_mutex);
5587
5588	event->cpu = cpu;
5589	event->attr = *attr;
5590	event->group_leader = group_leader;
5591	event->pmu = NULL;
5592	event->oncpu = -1;
5593
5594	event->parent = parent_event;
5595
5596	event->ns = get_pid_ns(current->nsproxy->pid_ns);
5597	event->id = atomic64_inc_return(&perf_event_id);
5598
5599	event->state = PERF_EVENT_STATE_INACTIVE;
5600
5601	if (task) {
5602	event->attach_state = PERF_ATTACH_TASK;
5603	#ifdef CONFIG_HAVE_HW_BREAKPOINT
5604	/*
5605	* hw_breakpoint is a bit difficult here..
5606	*/
5607	if (attr->type == PERF_TYPE_BREAKPOINT)
5608	event->hw.bp_target = task;
5609	#endif
5610	}
5611
5612	if (!overflow_handler && parent_event)
5613	overflow_handler = parent_event->overflow_handler;
5614
5615	event->overflow_handler = overflow_handler;
5616
5617	if (attr->disabled)
5618	event->state = PERF_EVENT_STATE_OFF;
5619
5620	pmu = NULL;
5621
5622	hwc = &event->hw;
5623	hwc->sample_period = attr->sample_period;
5624	if (attr->freq && attr->sample_freq)
5625	hwc->sample_period = 1;
5626	hwc->last_period = hwc->sample_period;
5627
5628	local64_set(&hwc->period_left, hwc->sample_period);
5629
5630	/*
5631	* we currently do not support PERF_FORMAT_GROUP on inherited events
5632	*/
5633	if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
5634	goto done;
5635
5636	pmu = perf_init_event(event);
5637
5638	done:
5639	err = 0;
5640	if (!pmu)
5641	err = -EINVAL;
5642	else if (IS_ERR(pmu))
5643	err = PTR_ERR(pmu);
5644
5645	if (err) {
5646	if (event->ns)
5647	put_pid_ns(event->ns);
5648	kfree(event);
5649	return ERR_PTR(err);
5650	}
5651
5652	event->pmu = pmu;
5653
5654	if (!event->parent) {
5655	if (event->attach_state & PERF_ATTACH_TASK)
5656	jump_label_inc(&perf_task_events);
5657	if (event->attr.mmap \|\| event->attr.mmap_data)
5658	atomic_inc(&nr_mmap_events);
5659	if (event->attr.comm)
5660	atomic_inc(&nr_comm_events);
5661	if (event->attr.task)
5662	atomic_inc(&nr_task_events);
5663	if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
5664	err = get_callchain_buffers();
5665	if (err) {
5666	free_event(event);
5667	return ERR_PTR(err);
5668	}
5669	}
5670	}
5671
5672	return event;
5673	}
5674
5675	static int perf_copy_attr(struct perf_event_attr __user *uattr,
5676	struct perf_event_attr *attr)
5677	{
5678	u32 size;
5679	int ret;
5680
5681	if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
5682	return -EFAULT;
5683
5684	/*
5685	* zero the full structure, so that a short copy will be nice.
5686	*/
5687	memset(attr, 0, sizeof(*attr));
5688
5689	ret = get_user(size, &uattr->size);
5690	if (ret)
5691	return ret;
5692
5693	if (size > PAGE_SIZE) /* silly large */
5694	goto err_size;
5695
5696	if (!size) /* abi compat */
5697	size = PERF_ATTR_SIZE_VER0;
5698
5699	if (size < PERF_ATTR_SIZE_VER0)
5700	goto err_size;
5701
5702	/*
5703	* If we're handed a bigger struct than we know of,
5704	* ensure all the unknown bits are 0 - i.e. new
5705	* user-space does not rely on any kernel feature
5706	* extensions we dont know about yet.
5707	*/
5708	if (size > sizeof(*attr)) {
5709	unsigned char __user *addr;
5710	unsigned char __user *end;
5711	unsigned char val;
5712
5713	addr = (void __user )uattr + sizeof(attr);
5714	end = (void __user *)uattr + size;
5715
5716	for (; addr < end; addr++) {
5717	ret = get_user(val, addr);
5718	if (ret)
5719	return ret;
5720	if (val)
5721	goto err_size;
5722	}
5723	size = sizeof(*attr);
5724	}
5725
5726	ret = copy_from_user(attr, uattr, size);
5727	if (ret)
5728	return -EFAULT;
5729
5730	/*
5731	* If the type exists, the corresponding creation will verify
5732	* the attr->config.
5733	*/
5734	if (attr->type >= PERF_TYPE_MAX)
5735	return -EINVAL;
5736
5737	if (attr->__reserved_1)
5738	return -EINVAL;
5739
5740	if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
5741	return -EINVAL;
5742
5743	if (attr->read_format & ~(PERF_FORMAT_MAX-1))
5744	return -EINVAL;
5745
5746	out:
5747	return ret;
5748
5749	err_size:
5750	put_user(sizeof(*attr), &uattr->size);
5751	ret = -E2BIG;
5752	goto out;
5753	}
5754
5755	static int
5756	perf_event_set_output(struct perf_event event, struct perf_event output_event)
5757	{
5758	struct perf_buffer buffer = NULL, old_buffer = NULL;
5759	int ret = -EINVAL;
5760
5761	if (!output_event)
5762	goto set;
5763
5764	/* don't allow circular references */
5765	if (event == output_event)
5766	goto out;
5767
5768	/*
5769	* Don't allow cross-cpu buffers
5770	*/
5771	if (output_event->cpu != event->cpu)
5772	goto out;
5773
5774	/*
5775	* If its not a per-cpu buffer, it must be the same task.
5776	*/
5777	if (output_event->cpu == -1 && output_event->ctx != event->ctx)
5778	goto out;
5779
5780	set:
5781	mutex_lock(&event->mmap_mutex);
5782	/* Can't redirect output if we've got an active mmap() */
5783	if (atomic_read(&event->mmap_count))
5784	goto unlock;
5785
5786	if (output_event) {
5787	/* get the buffer we want to redirect to */
5788	buffer = perf_buffer_get(output_event);
5789	if (!buffer)
5790	goto unlock;
5791	}
5792
5793	old_buffer = event->buffer;
5794	rcu_assign_pointer(event->buffer, buffer);
5795	ret = 0;
5796	unlock:
5797	mutex_unlock(&event->mmap_mutex);
5798
5799	if (old_buffer)
5800	perf_buffer_put(old_buffer);
5801	out:
5802	return ret;
5803	}
5804
5805	/**
5806	* sys_perf_event_open - open a performance event, associate it to a task/cpu
5807	*
5808	* @attr_uptr: event_id type attributes for monitoring/sampling
5809	* @pid: target pid
5810	* @cpu: target cpu
5811	* @group_fd: group leader event fd
5812	*/
5813	SYSCALL_DEFINE5(perf_event_open,
5814	struct perf_event_attr __user *, attr_uptr,
5815	pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
5816	{
5817	struct perf_event group_leader = NULL, output_event = NULL;
5818	struct perf_event event, sibling;
5819	struct perf_event_attr attr;
5820	struct perf_event_context *ctx;
5821	struct file *event_file = NULL;
5822	struct file *group_file = NULL;
5823	struct task_struct *task = NULL;
5824	struct pmu *pmu;
5825	int event_fd;
5826	int move_group = 0;
5827	int fput_needed = 0;
5828	int err;
5829
5830	/* for future expandability... */
5831	if (flags & ~(PERF_FLAG_FD_NO_GROUP \| PERF_FLAG_FD_OUTPUT))
5832	return -EINVAL;
5833
5834	err = perf_copy_attr(attr_uptr, &attr);
5835	if (err)
5836	return err;
5837
5838	if (!attr.exclude_kernel) {
5839	if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
5840	return -EACCES;
5841	}
5842
5843	if (attr.freq) {
5844	if (attr.sample_freq > sysctl_perf_event_sample_rate)
5845	return -EINVAL;
5846	}
5847
5848	event_fd = get_unused_fd_flags(O_RDWR);
5849	if (event_fd < 0)
5850	return event_fd;
5851
5852	if (group_fd != -1) {
5853	group_leader = perf_fget_light(group_fd, &fput_needed);
5854	if (IS_ERR(group_leader)) {
5855	err = PTR_ERR(group_leader);
5856	goto err_fd;
5857	}
5858	group_file = group_leader->filp;
5859	if (flags & PERF_FLAG_FD_OUTPUT)
5860	output_event = group_leader;
5861	if (flags & PERF_FLAG_FD_NO_GROUP)
5862	group_leader = NULL;
5863	}
5864
5865	if (pid != -1) {
5866	task = find_lively_task_by_vpid(pid);
5867	if (IS_ERR(task)) {
5868	err = PTR_ERR(task);
5869	goto err_group_fd;
5870	}
5871	}
5872
5873	event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, NULL);
5874	if (IS_ERR(event)) {
5875	err = PTR_ERR(event);
5876	goto err_task;
5877	}
5878
5879	/*
5880	* Special case software events and allow them to be part of
5881	* any hardware group.
5882	*/
5883	pmu = event->pmu;
5884
5885	if (group_leader &&
5886	(is_software_event(event) != is_software_event(group_leader))) {
5887	if (is_software_event(event)) {
5888	/*
5889	* If event and group_leader are not both a software
5890	* event, and event is, then group leader is not.
5891	*
5892	* Allow the addition of software events to !software
5893	* groups, this is safe because software events never
5894	* fail to schedule.
5895	*/
5896	pmu = group_leader->pmu;
5897	} else if (is_software_event(group_leader) &&
5898	(group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
5899	/*
5900	* In case the group is a pure software group, and we
5901	* try to add a hardware event, move the whole group to
5902	* the hardware context.
5903	*/
5904	move_group = 1;
5905	}
5906	}
5907
5908	/*
5909	* Get the target context (task or percpu):
5910	*/
5911	ctx = find_get_context(pmu, task, cpu);
5912	if (IS_ERR(ctx)) {
5913	err = PTR_ERR(ctx);
5914	goto err_alloc;
5915	}
5916
5917	/*
5918	* Look up the group leader (we will attach this event to it):
5919	*/
5920	if (group_leader) {
5921	err = -EINVAL;
5922
5923	/*
5924	* Do not allow a recursive hierarchy (this new sibling
5925	* becoming part of another group-sibling):
5926	*/
5927	if (group_leader->group_leader != group_leader)
5928	goto err_context;
5929	/*
5930	* Do not allow to attach to a group in a different
5931	* task or CPU context:
5932	*/
5933	if (move_group) {
5934	if (group_leader->ctx->type != ctx->type)
5935	goto err_context;
5936	} else {
5937	if (group_leader->ctx != ctx)
5938	goto err_context;
5939	}
5940
5941	/*
5942	* Only a group leader can be exclusive or pinned
5943	*/
5944	if (attr.exclusive \|\| attr.pinned)
5945	goto err_context;
5946	}
5947
5948	if (output_event) {
5949	err = perf_event_set_output(event, output_event);
5950	if (err)
5951	goto err_context;
5952	}
5953
5954	event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, O_RDWR);
5955	if (IS_ERR(event_file)) {
5956	err = PTR_ERR(event_file);
5957	goto err_context;
5958	}
5959
5960	if (move_group) {
5961	struct perf_event_context *gctx = group_leader->ctx;
5962
5963	mutex_lock(&gctx->mutex);
5964	perf_event_remove_from_context(group_leader);
5965	list_for_each_entry(sibling, &group_leader->sibling_list,
5966	group_entry) {
5967	perf_event_remove_from_context(sibling);
5968	put_ctx(gctx);
5969	}
5970	mutex_unlock(&gctx->mutex);
5971	put_ctx(gctx);
5972	}
5973
5974	event->filp = event_file;
5975	WARN_ON_ONCE(ctx->parent_ctx);
5976	mutex_lock(&ctx->mutex);
5977
5978	if (move_group) {
5979	perf_install_in_context(ctx, group_leader, cpu);
5980	get_ctx(ctx);
5981	list_for_each_entry(sibling, &group_leader->sibling_list,
5982	group_entry) {
5983	perf_install_in_context(ctx, sibling, cpu);
5984	get_ctx(ctx);
5985	}
5986	}
5987
5988	perf_install_in_context(ctx, event, cpu);
5989	++ctx->generation;
5990	mutex_unlock(&ctx->mutex);
5991
5992	event->owner = current;
5993
5994	mutex_lock(&current->perf_event_mutex);
5995	list_add_tail(&event->owner_entry, &current->perf_event_list);
5996	mutex_unlock(&current->perf_event_mutex);
5997
5998	/*
5999	* Precalculate sample_data sizes
6000	*/
6001	perf_event__header_size(event);
6002	perf_event__id_header_size(event);
6003
6004	/*
6005	* Drop the reference on the group_event after placing the
6006	* new event on the sibling_list. This ensures destruction
6007	* of the group leader will find the pointer to itself in
6008	* perf_group_detach().
6009	*/
6010	fput_light(group_file, fput_needed);
6011	fd_install(event_fd, event_file);
6012	return event_fd;
6013
6014	err_context:
6015	put_ctx(ctx);
6016	err_alloc:
6017	free_event(event);
6018	err_task:
6019	if (task)
6020	put_task_struct(task);
6021	err_group_fd:
6022	fput_light(group_file, fput_needed);
6023	err_fd:
6024	put_unused_fd(event_fd);
6025	return err;
6026	}
6027
6028	/**
6029	* perf_event_create_kernel_counter
6030	*
6031	* @attr: attributes of the counter to create
6032	* @cpu: cpu in which the counter is bound
6033	* @task: task to profile (NULL for percpu)
6034	*/
6035	struct perf_event *
6036	perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
6037	struct task_struct *task,
6038	perf_overflow_handler_t overflow_handler)
6039	{
6040	struct perf_event_context *ctx;
6041	struct perf_event *event;
6042	int err;
6043
6044	/*
6045	* Get the target context (task or percpu):
6046	*/
6047
6048	event = perf_event_alloc(attr, cpu, task, NULL, NULL, overflow_handler);
6049	if (IS_ERR(event)) {
6050	err = PTR_ERR(event);
6051	goto err;
6052	}
6053
6054	ctx = find_get_context(event->pmu, task, cpu);
6055	if (IS_ERR(ctx)) {
6056	err = PTR_ERR(ctx);
6057	goto err_free;
6058	}
6059
6060	event->filp = NULL;
6061	WARN_ON_ONCE(ctx->parent_ctx);
6062	mutex_lock(&ctx->mutex);
6063	perf_install_in_context(ctx, event, cpu);
6064	++ctx->generation;
6065	mutex_unlock(&ctx->mutex);
6066
6067	return event;
6068
6069	err_free:
6070	free_event(event);
6071	err:
6072	return ERR_PTR(err);
6073	}
6074	EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
6075
6076	static void sync_child_event(struct perf_event *child_event,
6077	struct task_struct *child)
6078	{
6079	struct perf_event *parent_event = child_event->parent;
6080	u64 child_val;
6081
6082	if (child_event->attr.inherit_stat)
6083	perf_event_read_event(child_event, child);
6084
6085	child_val = perf_event_count(child_event);
6086
6087	/*
6088	* Add back the child's count to the parent's count:
6089	*/
6090	atomic64_add(child_val, &parent_event->child_count);
6091	atomic64_add(child_event->total_time_enabled,
6092	&parent_event->child_total_time_enabled);
6093	atomic64_add(child_event->total_time_running,
6094	&parent_event->child_total_time_running);
6095
6096	/*
6097	* Remove this event from the parent's list
6098	*/
6099	WARN_ON_ONCE(parent_event->ctx->parent_ctx);
6100	mutex_lock(&parent_event->child_mutex);
6101	list_del_init(&child_event->child_list);
6102	mutex_unlock(&parent_event->child_mutex);
6103
6104	/*
6105	* Release the parent event, if this was the last
6106	* reference to it.
6107	*/
6108	fput(parent_event->filp);
6109	}
6110
6111	static void
6112	__perf_event_exit_task(struct perf_event *child_event,
6113	struct perf_event_context *child_ctx,
6114	struct task_struct *child)
6115	{
6116	struct perf_event *parent_event;
6117
6118	perf_event_remove_from_context(child_event);
6119
6120	parent_event = child_event->parent;
6121	/*
6122	* It can happen that parent exits first, and has events
6123	* that are still around due to the child reference. These
6124	* events need to be zapped - but otherwise linger.
6125	*/
6126	if (parent_event) {
6127	sync_child_event(child_event, child);
6128	free_event(child_event);
6129	}
6130	}
6131
6132	static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
6133	{
6134	struct perf_event child_event, tmp;
6135	struct perf_event_context *child_ctx;
6136	unsigned long flags;
6137
6138	if (likely(!child->perf_event_ctxp[ctxn])) {
6139	perf_event_task(child, NULL, 0);
6140	return;
6141	}
6142
6143	local_irq_save(flags);
6144	/*
6145	* We can't reschedule here because interrupts are disabled,
6146	* and either child is current or it is a task that can't be
6147	* scheduled, so we are now safe from rescheduling changing
6148	* our context.
6149	*/
6150	child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);
6151	task_ctx_sched_out(child_ctx, EVENT_ALL);
6152
6153	/*