perf: Reimplement frequency driven sampling
[linux-2.6.git] / 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/file.h>
17 #include <linux/poll.h>
18 #include <linux/sysfs.h>
19 #include <linux/dcache.h>
20 #include <linux/percpu.h>
21 #include <linux/ptrace.h>
22 #include <linux/vmstat.h>
23 #include <linux/vmalloc.h>
24 #include <linux/hardirq.h>
25 #include <linux/rculist.h>
26 #include <linux/uaccess.h>
27 #include <linux/syscalls.h>
28 #include <linux/anon_inodes.h>
29 #include <linux/kernel_stat.h>
30 #include <linux/perf_event.h>
31 #include <linux/ftrace_event.h>
32 #include <linux/hw_breakpoint.h>
33
34 #include <asm/irq_regs.h>
35
36 /*
37  * Each CPU has a list of per CPU events:
38  */
39 static DEFINE_PER_CPU(struct perf_cpu_context, perf_cpu_context);
40
41 int perf_max_events __read_mostly = 1;
42 static int perf_reserved_percpu __read_mostly;
43 static int perf_overcommit __read_mostly = 1;
44
45 static atomic_t nr_events __read_mostly;
46 static atomic_t nr_mmap_events __read_mostly;
47 static atomic_t nr_comm_events __read_mostly;
48 static atomic_t nr_task_events __read_mostly;
49
50 /*
51  * perf event paranoia level:
52  *  -1 - not paranoid at all
53  *   0 - disallow raw tracepoint access for unpriv
54  *   1 - disallow cpu events for unpriv
55  *   2 - disallow kernel profiling for unpriv
56  */
57 int sysctl_perf_event_paranoid __read_mostly = 1;
58
59 static inline bool perf_paranoid_tracepoint_raw(void)
60 {
61         return sysctl_perf_event_paranoid > -1;
62 }
63
64 static inline bool perf_paranoid_cpu(void)
65 {
66         return sysctl_perf_event_paranoid > 0;
67 }
68
69 static inline bool perf_paranoid_kernel(void)
70 {
71         return sysctl_perf_event_paranoid > 1;
72 }
73
74 int sysctl_perf_event_mlock __read_mostly = 512; /* 'free' kb per user */
75
76 /*
77  * max perf event sample rate
78  */
79 int sysctl_perf_event_sample_rate __read_mostly = 100000;
80
81 static atomic64_t perf_event_id;
82
83 /*
84  * Lock for (sysadmin-configurable) event reservations:
85  */
86 static DEFINE_SPINLOCK(perf_resource_lock);
87
88 /*
89  * Architecture provided APIs - weak aliases:
90  */
91 extern __weak const struct pmu *hw_perf_event_init(struct perf_event *event)
92 {
93         return NULL;
94 }
95
96 void __weak hw_perf_disable(void)               { barrier(); }
97 void __weak hw_perf_enable(void)                { barrier(); }
98
99 void __weak hw_perf_event_setup(int cpu)        { barrier(); }
100 void __weak hw_perf_event_setup_online(int cpu) { barrier(); }
101
102 int __weak
103 hw_perf_group_sched_in(struct perf_event *group_leader,
104                struct perf_cpu_context *cpuctx,
105                struct perf_event_context *ctx, int cpu)
106 {
107         return 0;
108 }
109
110 void __weak perf_event_print_debug(void)        { }
111
112 static DEFINE_PER_CPU(int, perf_disable_count);
113
114 void __perf_disable(void)
115 {
116         __get_cpu_var(perf_disable_count)++;
117 }
118
119 bool __perf_enable(void)
120 {
121         return !--__get_cpu_var(perf_disable_count);
122 }
123
124 void perf_disable(void)
125 {
126         __perf_disable();
127         hw_perf_disable();
128 }
129
130 void perf_enable(void)
131 {
132         if (__perf_enable())
133                 hw_perf_enable();
134 }
135
136 static void get_ctx(struct perf_event_context *ctx)
137 {
138         WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
139 }
140
141 static void free_ctx(struct rcu_head *head)
142 {
143         struct perf_event_context *ctx;
144
145         ctx = container_of(head, struct perf_event_context, rcu_head);
146         kfree(ctx);
147 }
148
149 static void put_ctx(struct perf_event_context *ctx)
150 {
151         if (atomic_dec_and_test(&ctx->refcount)) {
152                 if (ctx->parent_ctx)
153                         put_ctx(ctx->parent_ctx);
154                 if (ctx->task)
155                         put_task_struct(ctx->task);
156                 call_rcu(&ctx->rcu_head, free_ctx);
157         }
158 }
159
160 static void unclone_ctx(struct perf_event_context *ctx)
161 {
162         if (ctx->parent_ctx) {
163                 put_ctx(ctx->parent_ctx);
164                 ctx->parent_ctx = NULL;
165         }
166 }
167
168 /*
169  * If we inherit events we want to return the parent event id
170  * to userspace.
171  */
172 static u64 primary_event_id(struct perf_event *event)
173 {
174         u64 id = event->id;
175
176         if (event->parent)
177                 id = event->parent->id;
178
179         return id;
180 }
181
182 /*
183  * Get the perf_event_context for a task and lock it.
184  * This has to cope with with the fact that until it is locked,
185  * the context could get moved to another task.
186  */
187 static struct perf_event_context *
188 perf_lock_task_context(struct task_struct *task, unsigned long *flags)
189 {
190         struct perf_event_context *ctx;
191
192         rcu_read_lock();
193  retry:
194         ctx = rcu_dereference(task->perf_event_ctxp);
195         if (ctx) {
196                 /*
197                  * If this context is a clone of another, it might
198                  * get swapped for another underneath us by
199                  * perf_event_task_sched_out, though the
200                  * rcu_read_lock() protects us from any context
201                  * getting freed.  Lock the context and check if it
202                  * got swapped before we could get the lock, and retry
203                  * if so.  If we locked the right context, then it
204                  * can't get swapped on us any more.
205                  */
206                 raw_spin_lock_irqsave(&ctx->lock, *flags);
207                 if (ctx != rcu_dereference(task->perf_event_ctxp)) {
208                         raw_spin_unlock_irqrestore(&ctx->lock, *flags);
209                         goto retry;
210                 }
211
212                 if (!atomic_inc_not_zero(&ctx->refcount)) {
213                         raw_spin_unlock_irqrestore(&ctx->lock, *flags);
214                         ctx = NULL;
215                 }
216         }
217         rcu_read_unlock();
218         return ctx;
219 }
220
221 /*
222  * Get the context for a task and increment its pin_count so it
223  * can't get swapped to another task.  This also increments its
224  * reference count so that the context can't get freed.
225  */
226 static struct perf_event_context *perf_pin_task_context(struct task_struct *task)
227 {
228         struct perf_event_context *ctx;
229         unsigned long flags;
230
231         ctx = perf_lock_task_context(task, &flags);
232         if (ctx) {
233                 ++ctx->pin_count;
234                 raw_spin_unlock_irqrestore(&ctx->lock, flags);
235         }
236         return ctx;
237 }
238
239 static void perf_unpin_context(struct perf_event_context *ctx)
240 {
241         unsigned long flags;
242
243         raw_spin_lock_irqsave(&ctx->lock, flags);
244         --ctx->pin_count;
245         raw_spin_unlock_irqrestore(&ctx->lock, flags);
246         put_ctx(ctx);
247 }
248
249 static inline u64 perf_clock(void)
250 {
251         return cpu_clock(smp_processor_id());
252 }
253
254 /*
255  * Update the record of the current time in a context.
256  */
257 static void update_context_time(struct perf_event_context *ctx)
258 {
259         u64 now = perf_clock();
260
261         ctx->time += now - ctx->timestamp;
262         ctx->timestamp = now;
263 }
264
265 /*
266  * Update the total_time_enabled and total_time_running fields for a event.
267  */
268 static void update_event_times(struct perf_event *event)
269 {
270         struct perf_event_context *ctx = event->ctx;
271         u64 run_end;
272
273         if (event->state < PERF_EVENT_STATE_INACTIVE ||
274             event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
275                 return;
276
277         if (ctx->is_active)
278                 run_end = ctx->time;
279         else
280                 run_end = event->tstamp_stopped;
281
282         event->total_time_enabled = run_end - event->tstamp_enabled;
283
284         if (event->state == PERF_EVENT_STATE_INACTIVE)
285                 run_end = event->tstamp_stopped;
286         else
287                 run_end = ctx->time;
288
289         event->total_time_running = run_end - event->tstamp_running;
290 }
291
292 static struct list_head *
293 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
294 {
295         if (event->attr.pinned)
296                 return &ctx->pinned_groups;
297         else
298                 return &ctx->flexible_groups;
299 }
300
301 /*
302  * Add a event from the lists for its context.
303  * Must be called with ctx->mutex and ctx->lock held.
304  */
305 static void
306 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
307 {
308         struct perf_event *group_leader = event->group_leader;
309
310         /*
311          * Depending on whether it is a standalone or sibling event,
312          * add it straight to the context's event list, or to the group
313          * leader's sibling list:
314          */
315         if (group_leader == event) {
316                 struct list_head *list;
317
318                 if (is_software_event(event))
319                         event->group_flags |= PERF_GROUP_SOFTWARE;
320
321                 list = ctx_group_list(event, ctx);
322                 list_add_tail(&event->group_entry, list);
323         } else {
324                 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
325                     !is_software_event(event))
326                         group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
327
328                 list_add_tail(&event->group_entry, &group_leader->sibling_list);
329                 group_leader->nr_siblings++;
330         }
331
332         list_add_rcu(&event->event_entry, &ctx->event_list);
333         ctx->nr_events++;
334         if (event->attr.inherit_stat)
335                 ctx->nr_stat++;
336 }
337
338 /*
339  * Remove a event from the lists for its context.
340  * Must be called with ctx->mutex and ctx->lock held.
341  */
342 static void
343 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
344 {
345         struct perf_event *sibling, *tmp;
346
347         if (list_empty(&event->group_entry))
348                 return;
349         ctx->nr_events--;
350         if (event->attr.inherit_stat)
351                 ctx->nr_stat--;
352
353         list_del_init(&event->group_entry);
354         list_del_rcu(&event->event_entry);
355
356         if (event->group_leader != event)
357                 event->group_leader->nr_siblings--;
358
359         update_event_times(event);
360
361         /*
362          * If event was in error state, then keep it
363          * that way, otherwise bogus counts will be
364          * returned on read(). The only way to get out
365          * of error state is by explicit re-enabling
366          * of the event
367          */
368         if (event->state > PERF_EVENT_STATE_OFF)
369                 event->state = PERF_EVENT_STATE_OFF;
370
371         /*
372          * If this was a group event with sibling events then
373          * upgrade the siblings to singleton events by adding them
374          * to the context list directly:
375          */
376         list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
377                 struct list_head *list;
378
379                 list = ctx_group_list(event, ctx);
380                 list_move_tail(&sibling->group_entry, list);
381                 sibling->group_leader = sibling;
382
383                 /* Inherit group flags from the previous leader */
384                 sibling->group_flags = event->group_flags;
385         }
386 }
387
388 static void
389 event_sched_out(struct perf_event *event,
390                   struct perf_cpu_context *cpuctx,
391                   struct perf_event_context *ctx)
392 {
393         if (event->state != PERF_EVENT_STATE_ACTIVE)
394                 return;
395
396         event->state = PERF_EVENT_STATE_INACTIVE;
397         if (event->pending_disable) {
398                 event->pending_disable = 0;
399                 event->state = PERF_EVENT_STATE_OFF;
400         }
401         event->tstamp_stopped = ctx->time;
402         event->pmu->disable(event);
403         event->oncpu = -1;
404
405         if (!is_software_event(event))
406                 cpuctx->active_oncpu--;
407         ctx->nr_active--;
408         if (event->attr.exclusive || !cpuctx->active_oncpu)
409                 cpuctx->exclusive = 0;
410 }
411
412 static void
413 group_sched_out(struct perf_event *group_event,
414                 struct perf_cpu_context *cpuctx,
415                 struct perf_event_context *ctx)
416 {
417         struct perf_event *event;
418
419         if (group_event->state != PERF_EVENT_STATE_ACTIVE)
420                 return;
421
422         event_sched_out(group_event, cpuctx, ctx);
423
424         /*
425          * Schedule out siblings (if any):
426          */
427         list_for_each_entry(event, &group_event->sibling_list, group_entry)
428                 event_sched_out(event, cpuctx, ctx);
429
430         if (group_event->attr.exclusive)
431                 cpuctx->exclusive = 0;
432 }
433
434 /*
435  * Cross CPU call to remove a performance event
436  *
437  * We disable the event on the hardware level first. After that we
438  * remove it from the context list.
439  */
440 static void __perf_event_remove_from_context(void *info)
441 {
442         struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
443         struct perf_event *event = info;
444         struct perf_event_context *ctx = event->ctx;
445
446         /*
447          * If this is a task context, we need to check whether it is
448          * the current task context of this cpu. If not it has been
449          * scheduled out before the smp call arrived.
450          */
451         if (ctx->task && cpuctx->task_ctx != ctx)
452                 return;
453
454         raw_spin_lock(&ctx->lock);
455         /*
456          * Protect the list operation against NMI by disabling the
457          * events on a global level.
458          */
459         perf_disable();
460
461         event_sched_out(event, cpuctx, ctx);
462
463         list_del_event(event, ctx);
464
465         if (!ctx->task) {
466                 /*
467                  * Allow more per task events with respect to the
468                  * reservation:
469                  */
470                 cpuctx->max_pertask =
471                         min(perf_max_events - ctx->nr_events,
472                             perf_max_events - perf_reserved_percpu);
473         }
474
475         perf_enable();
476         raw_spin_unlock(&ctx->lock);
477 }
478
479
480 /*
481  * Remove the event from a task's (or a CPU's) list of events.
482  *
483  * Must be called with ctx->mutex held.
484  *
485  * CPU events are removed with a smp call. For task events we only
486  * call when the task is on a CPU.
487  *
488  * If event->ctx is a cloned context, callers must make sure that
489  * every task struct that event->ctx->task could possibly point to
490  * remains valid.  This is OK when called from perf_release since
491  * that only calls us on the top-level context, which can't be a clone.
492  * When called from perf_event_exit_task, it's OK because the
493  * context has been detached from its task.
494  */
495 static void perf_event_remove_from_context(struct perf_event *event)
496 {
497         struct perf_event_context *ctx = event->ctx;
498         struct task_struct *task = ctx->task;
499
500         if (!task) {
501                 /*
502                  * Per cpu events are removed via an smp call and
503                  * the removal is always successful.
504                  */
505                 smp_call_function_single(event->cpu,
506                                          __perf_event_remove_from_context,
507                                          event, 1);
508                 return;
509         }
510
511 retry:
512         task_oncpu_function_call(task, __perf_event_remove_from_context,
513                                  event);
514
515         raw_spin_lock_irq(&ctx->lock);
516         /*
517          * If the context is active we need to retry the smp call.
518          */
519         if (ctx->nr_active && !list_empty(&event->group_entry)) {
520                 raw_spin_unlock_irq(&ctx->lock);
521                 goto retry;
522         }
523
524         /*
525          * The lock prevents that this context is scheduled in so we
526          * can remove the event safely, if the call above did not
527          * succeed.
528          */
529         if (!list_empty(&event->group_entry))
530                 list_del_event(event, ctx);
531         raw_spin_unlock_irq(&ctx->lock);
532 }
533
534 /*
535  * Update total_time_enabled and total_time_running for all events in a group.
536  */
537 static void update_group_times(struct perf_event *leader)
538 {
539         struct perf_event *event;
540
541         update_event_times(leader);
542         list_for_each_entry(event, &leader->sibling_list, group_entry)
543                 update_event_times(event);
544 }
545
546 /*
547  * Cross CPU call to disable a performance event
548  */
549 static void __perf_event_disable(void *info)
550 {
551         struct perf_event *event = info;
552         struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
553         struct perf_event_context *ctx = event->ctx;
554
555         /*
556          * If this is a per-task event, need to check whether this
557          * event's task is the current task on this cpu.
558          */
559         if (ctx->task && cpuctx->task_ctx != ctx)
560                 return;
561
562         raw_spin_lock(&ctx->lock);
563
564         /*
565          * If the event is on, turn it off.
566          * If it is in error state, leave it in error state.
567          */
568         if (event->state >= PERF_EVENT_STATE_INACTIVE) {
569                 update_context_time(ctx);
570                 update_group_times(event);
571                 if (event == event->group_leader)
572                         group_sched_out(event, cpuctx, ctx);
573                 else
574                         event_sched_out(event, cpuctx, ctx);
575                 event->state = PERF_EVENT_STATE_OFF;
576         }
577
578         raw_spin_unlock(&ctx->lock);
579 }
580
581 /*
582  * Disable a event.
583  *
584  * If event->ctx is a cloned context, callers must make sure that
585  * every task struct that event->ctx->task could possibly point to
586  * remains valid.  This condition is satisifed when called through
587  * perf_event_for_each_child or perf_event_for_each because they
588  * hold the top-level event's child_mutex, so any descendant that
589  * goes to exit will block in sync_child_event.
590  * When called from perf_pending_event it's OK because event->ctx
591  * is the current context on this CPU and preemption is disabled,
592  * hence we can't get into perf_event_task_sched_out for this context.
593  */
594 void perf_event_disable(struct perf_event *event)
595 {
596         struct perf_event_context *ctx = event->ctx;
597         struct task_struct *task = ctx->task;
598
599         if (!task) {
600                 /*
601                  * Disable the event on the cpu that it's on
602                  */
603                 smp_call_function_single(event->cpu, __perf_event_disable,
604                                          event, 1);
605                 return;
606         }
607
608  retry:
609         task_oncpu_function_call(task, __perf_event_disable, event);
610
611         raw_spin_lock_irq(&ctx->lock);
612         /*
613          * If the event is still active, we need to retry the cross-call.
614          */
615         if (event->state == PERF_EVENT_STATE_ACTIVE) {
616                 raw_spin_unlock_irq(&ctx->lock);
617                 goto retry;
618         }
619
620         /*
621          * Since we have the lock this context can't be scheduled
622          * in, so we can change the state safely.
623          */
624         if (event->state == PERF_EVENT_STATE_INACTIVE) {
625                 update_group_times(event);
626                 event->state = PERF_EVENT_STATE_OFF;
627         }
628
629         raw_spin_unlock_irq(&ctx->lock);
630 }
631
632 static int
633 event_sched_in(struct perf_event *event,
634                  struct perf_cpu_context *cpuctx,
635                  struct perf_event_context *ctx,
636                  int cpu)
637 {
638         if (event->state <= PERF_EVENT_STATE_OFF)
639                 return 0;
640
641         event->state = PERF_EVENT_STATE_ACTIVE;
642         event->oncpu = cpu;     /* TODO: put 'cpu' into cpuctx->cpu */
643         /*
644          * The new state must be visible before we turn it on in the hardware:
645          */
646         smp_wmb();
647
648         if (event->pmu->enable(event)) {
649                 event->state = PERF_EVENT_STATE_INACTIVE;
650                 event->oncpu = -1;
651                 return -EAGAIN;
652         }
653
654         event->tstamp_running += ctx->time - event->tstamp_stopped;
655
656         if (!is_software_event(event))
657                 cpuctx->active_oncpu++;
658         ctx->nr_active++;
659
660         if (event->attr.exclusive)
661                 cpuctx->exclusive = 1;
662
663         return 0;
664 }
665
666 static int
667 group_sched_in(struct perf_event *group_event,
668                struct perf_cpu_context *cpuctx,
669                struct perf_event_context *ctx,
670                int cpu)
671 {
672         struct perf_event *event, *partial_group;
673         int ret;
674
675         if (group_event->state == PERF_EVENT_STATE_OFF)
676                 return 0;
677
678         ret = hw_perf_group_sched_in(group_event, cpuctx, ctx, cpu);
679         if (ret)
680                 return ret < 0 ? ret : 0;
681
682         if (event_sched_in(group_event, cpuctx, ctx, cpu))
683                 return -EAGAIN;
684
685         /*
686          * Schedule in siblings as one group (if any):
687          */
688         list_for_each_entry(event, &group_event->sibling_list, group_entry) {
689                 if (event_sched_in(event, cpuctx, ctx, cpu)) {
690                         partial_group = event;
691                         goto group_error;
692                 }
693         }
694
695         return 0;
696
697 group_error:
698         /*
699          * Groups can be scheduled in as one unit only, so undo any
700          * partial group before returning:
701          */
702         list_for_each_entry(event, &group_event->sibling_list, group_entry) {
703                 if (event == partial_group)
704                         break;
705                 event_sched_out(event, cpuctx, ctx);
706         }
707         event_sched_out(group_event, cpuctx, ctx);
708
709         return -EAGAIN;
710 }
711
712 /*
713  * Work out whether we can put this event group on the CPU now.
714  */
715 static int group_can_go_on(struct perf_event *event,
716                            struct perf_cpu_context *cpuctx,
717                            int can_add_hw)
718 {
719         /*
720          * Groups consisting entirely of software events can always go on.
721          */
722         if (event->group_flags & PERF_GROUP_SOFTWARE)
723                 return 1;
724         /*
725          * If an exclusive group is already on, no other hardware
726          * events can go on.
727          */
728         if (cpuctx->exclusive)
729                 return 0;
730         /*
731          * If this group is exclusive and there are already
732          * events on the CPU, it can't go on.
733          */
734         if (event->attr.exclusive && cpuctx->active_oncpu)
735                 return 0;
736         /*
737          * Otherwise, try to add it if all previous groups were able
738          * to go on.
739          */
740         return can_add_hw;
741 }
742
743 static void add_event_to_ctx(struct perf_event *event,
744                                struct perf_event_context *ctx)
745 {
746         list_add_event(event, ctx);
747         event->tstamp_enabled = ctx->time;
748         event->tstamp_running = ctx->time;
749         event->tstamp_stopped = ctx->time;
750 }
751
752 /*
753  * Cross CPU call to install and enable a performance event
754  *
755  * Must be called with ctx->mutex held
756  */
757 static void __perf_install_in_context(void *info)
758 {
759         struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
760         struct perf_event *event = info;
761         struct perf_event_context *ctx = event->ctx;
762         struct perf_event *leader = event->group_leader;
763         int cpu = smp_processor_id();
764         int err;
765
766         /*
767          * If this is a task context, we need to check whether it is
768          * the current task context of this cpu. If not it has been
769          * scheduled out before the smp call arrived.
770          * Or possibly this is the right context but it isn't
771          * on this cpu because it had no events.
772          */
773         if (ctx->task && cpuctx->task_ctx != ctx) {
774                 if (cpuctx->task_ctx || ctx->task != current)
775                         return;
776                 cpuctx->task_ctx = ctx;
777         }
778
779         raw_spin_lock(&ctx->lock);
780         ctx->is_active = 1;
781         update_context_time(ctx);
782
783         /*
784          * Protect the list operation against NMI by disabling the
785          * events on a global level. NOP for non NMI based events.
786          */
787         perf_disable();
788
789         add_event_to_ctx(event, ctx);
790
791         if (event->cpu != -1 && event->cpu != smp_processor_id())
792                 goto unlock;
793
794         /*
795          * Don't put the event on if it is disabled or if
796          * it is in a group and the group isn't on.
797          */
798         if (event->state != PERF_EVENT_STATE_INACTIVE ||
799             (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE))
800                 goto unlock;
801
802         /*
803          * An exclusive event can't go on if there are already active
804          * hardware events, and no hardware event can go on if there
805          * is already an exclusive event on.
806          */
807         if (!group_can_go_on(event, cpuctx, 1))
808                 err = -EEXIST;
809         else
810                 err = event_sched_in(event, cpuctx, ctx, cpu);
811
812         if (err) {
813                 /*
814                  * This event couldn't go on.  If it is in a group
815                  * then we have to pull the whole group off.
816                  * If the event group is pinned then put it in error state.
817                  */
818                 if (leader != event)
819                         group_sched_out(leader, cpuctx, ctx);
820                 if (leader->attr.pinned) {
821                         update_group_times(leader);
822                         leader->state = PERF_EVENT_STATE_ERROR;
823                 }
824         }
825
826         if (!err && !ctx->task && cpuctx->max_pertask)
827                 cpuctx->max_pertask--;
828
829  unlock:
830         perf_enable();
831
832         raw_spin_unlock(&ctx->lock);
833 }
834
835 /*
836  * Attach a performance event to a context
837  *
838  * First we add the event to the list with the hardware enable bit
839  * in event->hw_config cleared.
840  *
841  * If the event is attached to a task which is on a CPU we use a smp
842  * call to enable it in the task context. The task might have been
843  * scheduled away, but we check this in the smp call again.
844  *
845  * Must be called with ctx->mutex held.
846  */
847 static void
848 perf_install_in_context(struct perf_event_context *ctx,
849                         struct perf_event *event,
850                         int cpu)
851 {
852         struct task_struct *task = ctx->task;
853
854         if (!task) {
855                 /*
856                  * Per cpu events are installed via an smp call and
857                  * the install is always successful.
858                  */
859                 smp_call_function_single(cpu, __perf_install_in_context,
860                                          event, 1);
861                 return;
862         }
863
864 retry:
865         task_oncpu_function_call(task, __perf_install_in_context,
866                                  event);
867
868         raw_spin_lock_irq(&ctx->lock);
869         /*
870          * we need to retry the smp call.
871          */
872         if (ctx->is_active && list_empty(&event->group_entry)) {
873                 raw_spin_unlock_irq(&ctx->lock);
874                 goto retry;
875         }
876
877         /*
878          * The lock prevents that this context is scheduled in so we
879          * can add the event safely, if it the call above did not
880          * succeed.
881          */
882         if (list_empty(&event->group_entry))
883                 add_event_to_ctx(event, ctx);
884         raw_spin_unlock_irq(&ctx->lock);
885 }
886
887 /*
888  * Put a event into inactive state and update time fields.
889  * Enabling the leader of a group effectively enables all
890  * the group members that aren't explicitly disabled, so we
891  * have to update their ->tstamp_enabled also.
892  * Note: this works for group members as well as group leaders
893  * since the non-leader members' sibling_lists will be empty.
894  */
895 static void __perf_event_mark_enabled(struct perf_event *event,
896                                         struct perf_event_context *ctx)
897 {
898         struct perf_event *sub;
899
900         event->state = PERF_EVENT_STATE_INACTIVE;
901         event->tstamp_enabled = ctx->time - event->total_time_enabled;
902         list_for_each_entry(sub, &event->sibling_list, group_entry)
903                 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
904                         sub->tstamp_enabled =
905                                 ctx->time - sub->total_time_enabled;
906 }
907
908 /*
909  * Cross CPU call to enable a performance event
910  */
911 static void __perf_event_enable(void *info)
912 {
913         struct perf_event *event = info;
914         struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
915         struct perf_event_context *ctx = event->ctx;
916         struct perf_event *leader = event->group_leader;
917         int err;
918
919         /*
920          * If this is a per-task event, need to check whether this
921          * event's task is the current task on this cpu.
922          */
923         if (ctx->task && cpuctx->task_ctx != ctx) {
924                 if (cpuctx->task_ctx || ctx->task != current)
925                         return;
926                 cpuctx->task_ctx = ctx;
927         }
928
929         raw_spin_lock(&ctx->lock);
930         ctx->is_active = 1;
931         update_context_time(ctx);
932
933         if (event->state >= PERF_EVENT_STATE_INACTIVE)
934                 goto unlock;
935         __perf_event_mark_enabled(event, ctx);
936
937         if (event->cpu != -1 && event->cpu != smp_processor_id())
938                 goto unlock;
939
940         /*
941          * If the event is in a group and isn't the group leader,
942          * then don't put it on unless the group is on.
943          */
944         if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
945                 goto unlock;
946
947         if (!group_can_go_on(event, cpuctx, 1)) {
948                 err = -EEXIST;
949         } else {
950                 perf_disable();
951                 if (event == leader)
952                         err = group_sched_in(event, cpuctx, ctx,
953                                              smp_processor_id());
954                 else
955                         err = event_sched_in(event, cpuctx, ctx,
956                                                smp_processor_id());
957                 perf_enable();
958         }
959
960         if (err) {
961                 /*
962                  * If this event can't go on and it's part of a
963                  * group, then the whole group has to come off.
964                  */
965                 if (leader != event)
966                         group_sched_out(leader, cpuctx, ctx);
967                 if (leader->attr.pinned) {
968                         update_group_times(leader);
969                         leader->state = PERF_EVENT_STATE_ERROR;
970                 }
971         }
972
973  unlock:
974         raw_spin_unlock(&ctx->lock);
975 }
976
977 /*
978  * Enable a event.
979  *
980  * If event->ctx is a cloned context, callers must make sure that
981  * every task struct that event->ctx->task could possibly point to
982  * remains valid.  This condition is satisfied when called through
983  * perf_event_for_each_child or perf_event_for_each as described
984  * for perf_event_disable.
985  */
986 void perf_event_enable(struct perf_event *event)
987 {
988         struct perf_event_context *ctx = event->ctx;
989         struct task_struct *task = ctx->task;
990
991         if (!task) {
992                 /*
993                  * Enable the event on the cpu that it's on
994                  */
995                 smp_call_function_single(event->cpu, __perf_event_enable,
996                                          event, 1);
997                 return;
998         }
999
1000         raw_spin_lock_irq(&ctx->lock);
1001         if (event->state >= PERF_EVENT_STATE_INACTIVE)
1002                 goto out;
1003
1004         /*
1005          * If the event is in error state, clear that first.
1006          * That way, if we see the event in error state below, we
1007          * know that it has gone back into error state, as distinct
1008          * from the task having been scheduled away before the
1009          * cross-call arrived.
1010          */
1011         if (event->state == PERF_EVENT_STATE_ERROR)
1012                 event->state = PERF_EVENT_STATE_OFF;
1013
1014  retry:
1015         raw_spin_unlock_irq(&ctx->lock);
1016         task_oncpu_function_call(task, __perf_event_enable, event);
1017
1018         raw_spin_lock_irq(&ctx->lock);
1019
1020         /*
1021          * If the context is active and the event is still off,
1022          * we need to retry the cross-call.
1023          */
1024         if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF)
1025                 goto retry;
1026
1027         /*
1028          * Since we have the lock this context can't be scheduled
1029          * in, so we can change the state safely.
1030          */
1031         if (event->state == PERF_EVENT_STATE_OFF)
1032                 __perf_event_mark_enabled(event, ctx);
1033
1034  out:
1035         raw_spin_unlock_irq(&ctx->lock);
1036 }
1037
1038 static int perf_event_refresh(struct perf_event *event, int refresh)
1039 {
1040         /*
1041          * not supported on inherited events
1042          */
1043         if (event->attr.inherit)
1044                 return -EINVAL;
1045
1046         atomic_add(refresh, &event->event_limit);
1047         perf_event_enable(event);
1048
1049         return 0;
1050 }
1051
1052 enum event_type_t {
1053         EVENT_FLEXIBLE = 0x1,
1054         EVENT_PINNED = 0x2,
1055         EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
1056 };
1057
1058 static void ctx_sched_out(struct perf_event_context *ctx,
1059                           struct perf_cpu_context *cpuctx,
1060                           enum event_type_t event_type)
1061 {
1062         struct perf_event *event;
1063
1064         raw_spin_lock(&ctx->lock);
1065         ctx->is_active = 0;
1066         if (likely(!ctx->nr_events))
1067                 goto out;
1068         update_context_time(ctx);
1069
1070         perf_disable();
1071         if (!ctx->nr_active)
1072                 goto out_enable;
1073
1074         if (event_type & EVENT_PINNED)
1075                 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
1076                         group_sched_out(event, cpuctx, ctx);
1077
1078         if (event_type & EVENT_FLEXIBLE)
1079                 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
1080                         group_sched_out(event, cpuctx, ctx);
1081
1082  out_enable:
1083         perf_enable();
1084  out:
1085         raw_spin_unlock(&ctx->lock);
1086 }
1087
1088 /*
1089  * Test whether two contexts are equivalent, i.e. whether they
1090  * have both been cloned from the same version of the same context
1091  * and they both have the same number of enabled events.
1092  * If the number of enabled events is the same, then the set
1093  * of enabled events should be the same, because these are both
1094  * inherited contexts, therefore we can't access individual events
1095  * in them directly with an fd; we can only enable/disable all
1096  * events via prctl, or enable/disable all events in a family
1097  * via ioctl, which will have the same effect on both contexts.
1098  */
1099 static int context_equiv(struct perf_event_context *ctx1,
1100                          struct perf_event_context *ctx2)
1101 {
1102         return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
1103                 && ctx1->parent_gen == ctx2->parent_gen
1104                 && !ctx1->pin_count && !ctx2->pin_count;
1105 }
1106
1107 static void __perf_event_sync_stat(struct perf_event *event,
1108                                      struct perf_event *next_event)
1109 {
1110         u64 value;
1111
1112         if (!event->attr.inherit_stat)
1113                 return;
1114
1115         /*
1116          * Update the event value, we cannot use perf_event_read()
1117          * because we're in the middle of a context switch and have IRQs
1118          * disabled, which upsets smp_call_function_single(), however
1119          * we know the event must be on the current CPU, therefore we
1120          * don't need to use it.
1121          */
1122         switch (event->state) {
1123         case PERF_EVENT_STATE_ACTIVE:
1124                 event->pmu->read(event);
1125                 /* fall-through */
1126
1127         case PERF_EVENT_STATE_INACTIVE:
1128                 update_event_times(event);
1129                 break;
1130
1131         default:
1132                 break;
1133         }
1134
1135         /*
1136          * In order to keep per-task stats reliable we need to flip the event
1137          * values when we flip the contexts.
1138          */
1139         value = atomic64_read(&next_event->count);
1140         value = atomic64_xchg(&event->count, value);
1141         atomic64_set(&next_event->count, value);
1142
1143         swap(event->total_time_enabled, next_event->total_time_enabled);
1144         swap(event->total_time_running, next_event->total_time_running);
1145
1146         /*
1147          * Since we swizzled the values, update the user visible data too.
1148          */
1149         perf_event_update_userpage(event);
1150         perf_event_update_userpage(next_event);
1151 }
1152
1153 #define list_next_entry(pos, member) \
1154         list_entry(pos->member.next, typeof(*pos), member)
1155
1156 static void perf_event_sync_stat(struct perf_event_context *ctx,
1157                                    struct perf_event_context *next_ctx)
1158 {
1159         struct perf_event *event, *next_event;
1160
1161         if (!ctx->nr_stat)
1162                 return;
1163
1164         update_context_time(ctx);
1165
1166         event = list_first_entry(&ctx->event_list,
1167                                    struct perf_event, event_entry);
1168
1169         next_event = list_first_entry(&next_ctx->event_list,
1170                                         struct perf_event, event_entry);
1171
1172         while (&event->event_entry != &ctx->event_list &&
1173                &next_event->event_entry != &next_ctx->event_list) {
1174
1175                 __perf_event_sync_stat(event, next_event);
1176
1177                 event = list_next_entry(event, event_entry);
1178                 next_event = list_next_entry(next_event, event_entry);
1179         }
1180 }
1181
1182 /*
1183  * Called from scheduler to remove the events of the current task,
1184  * with interrupts disabled.
1185  *
1186  * We stop each event and update the event value in event->count.
1187  *
1188  * This does not protect us against NMI, but disable()
1189  * sets the disabled bit in the control field of event _before_
1190  * accessing the event control register. If a NMI hits, then it will
1191  * not restart the event.
1192  */
1193 void perf_event_task_sched_out(struct task_struct *task,
1194                                  struct task_struct *next)
1195 {
1196         struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1197         struct perf_event_context *ctx = task->perf_event_ctxp;
1198         struct perf_event_context *next_ctx;
1199         struct perf_event_context *parent;
1200         struct pt_regs *regs;
1201         int do_switch = 1;
1202
1203         regs = task_pt_regs(task);
1204         perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, regs, 0);
1205
1206         if (likely(!ctx || !cpuctx->task_ctx))
1207                 return;
1208
1209         rcu_read_lock();
1210         parent = rcu_dereference(ctx->parent_ctx);
1211         next_ctx = next->perf_event_ctxp;
1212         if (parent && next_ctx &&
1213             rcu_dereference(next_ctx->parent_ctx) == parent) {
1214                 /*
1215                  * Looks like the two contexts are clones, so we might be
1216                  * able to optimize the context switch.  We lock both
1217                  * contexts and check that they are clones under the
1218                  * lock (including re-checking that neither has been
1219                  * uncloned in the meantime).  It doesn't matter which
1220                  * order we take the locks because no other cpu could
1221                  * be trying to lock both of these tasks.
1222                  */
1223                 raw_spin_lock(&ctx->lock);
1224                 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
1225                 if (context_equiv(ctx, next_ctx)) {
1226                         /*
1227                          * XXX do we need a memory barrier of sorts
1228                          * wrt to rcu_dereference() of perf_event_ctxp
1229                          */
1230                         task->perf_event_ctxp = next_ctx;
1231                         next->perf_event_ctxp = ctx;
1232                         ctx->task = next;
1233                         next_ctx->task = task;
1234                         do_switch = 0;
1235
1236                         perf_event_sync_stat(ctx, next_ctx);
1237                 }
1238                 raw_spin_unlock(&next_ctx->lock);
1239                 raw_spin_unlock(&ctx->lock);
1240         }
1241         rcu_read_unlock();
1242
1243         if (do_switch) {
1244                 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
1245                 cpuctx->task_ctx = NULL;
1246         }
1247 }
1248
1249 static void task_ctx_sched_out(struct perf_event_context *ctx,
1250                                enum event_type_t event_type)
1251 {
1252         struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1253
1254         if (!cpuctx->task_ctx)
1255                 return;
1256
1257         if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
1258                 return;
1259
1260         ctx_sched_out(ctx, cpuctx, event_type);
1261         cpuctx->task_ctx = NULL;
1262 }
1263
1264 /*
1265  * Called with IRQs disabled
1266  */
1267 static void __perf_event_task_sched_out(struct perf_event_context *ctx)
1268 {
1269         task_ctx_sched_out(ctx, EVENT_ALL);
1270 }
1271
1272 /*
1273  * Called with IRQs disabled
1274  */
1275 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
1276                               enum event_type_t event_type)
1277 {
1278         ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
1279 }
1280
1281 static void
1282 ctx_pinned_sched_in(struct perf_event_context *ctx,
1283                     struct perf_cpu_context *cpuctx,
1284                     int cpu)
1285 {
1286         struct perf_event *event;
1287
1288         list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
1289                 if (event->state <= PERF_EVENT_STATE_OFF)
1290                         continue;
1291                 if (event->cpu != -1 && event->cpu != cpu)
1292                         continue;
1293
1294                 if (group_can_go_on(event, cpuctx, 1))
1295                         group_sched_in(event, cpuctx, ctx, cpu);
1296
1297                 /*
1298                  * If this pinned group hasn't been scheduled,
1299                  * put it in error state.
1300                  */
1301                 if (event->state == PERF_EVENT_STATE_INACTIVE) {
1302                         update_group_times(event);
1303                         event->state = PERF_EVENT_STATE_ERROR;
1304                 }
1305         }
1306 }
1307
1308 static void
1309 ctx_flexible_sched_in(struct perf_event_context *ctx,
1310                       struct perf_cpu_context *cpuctx,
1311                       int cpu)
1312 {
1313         struct perf_event *event;
1314         int can_add_hw = 1;
1315
1316         list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
1317                 /* Ignore events in OFF or ERROR state */
1318                 if (event->state <= PERF_EVENT_STATE_OFF)
1319                         continue;
1320                 /*
1321                  * Listen to the 'cpu' scheduling filter constraint
1322                  * of events:
1323                  */
1324                 if (event->cpu != -1 && event->cpu != cpu)
1325                         continue;
1326
1327                 if (group_can_go_on(event, cpuctx, can_add_hw))
1328                         if (group_sched_in(event, cpuctx, ctx, cpu))
1329                                 can_add_hw = 0;
1330         }
1331 }
1332
1333 static void
1334 ctx_sched_in(struct perf_event_context *ctx,
1335              struct perf_cpu_context *cpuctx,
1336              enum event_type_t event_type)
1337 {
1338         int cpu = smp_processor_id();
1339
1340         raw_spin_lock(&ctx->lock);
1341         ctx->is_active = 1;
1342         if (likely(!ctx->nr_events))
1343                 goto out;
1344
1345         ctx->timestamp = perf_clock();
1346
1347         perf_disable();
1348
1349         /*
1350          * First go through the list and put on any pinned groups
1351          * in order to give them the best chance of going on.
1352          */
1353         if (event_type & EVENT_PINNED)
1354                 ctx_pinned_sched_in(ctx, cpuctx, cpu);
1355
1356         /* Then walk through the lower prio flexible groups */
1357         if (event_type & EVENT_FLEXIBLE)
1358                 ctx_flexible_sched_in(ctx, cpuctx, cpu);
1359
1360         perf_enable();
1361  out:
1362         raw_spin_unlock(&ctx->lock);
1363 }
1364
1365 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
1366                              enum event_type_t event_type)
1367 {
1368         struct perf_event_context *ctx = &cpuctx->ctx;
1369
1370         ctx_sched_in(ctx, cpuctx, event_type);
1371 }
1372
1373 static void task_ctx_sched_in(struct task_struct *task,
1374                               enum event_type_t event_type)
1375 {
1376         struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1377         struct perf_event_context *ctx = task->perf_event_ctxp;
1378
1379         if (likely(!ctx))
1380                 return;
1381         if (cpuctx->task_ctx == ctx)
1382                 return;
1383         ctx_sched_in(ctx, cpuctx, event_type);
1384         cpuctx->task_ctx = ctx;
1385 }
1386 /*
1387  * Called from scheduler to add the events of the current task
1388  * with interrupts disabled.
1389  *
1390  * We restore the event value and then enable it.
1391  *
1392  * This does not protect us against NMI, but enable()
1393  * sets the enabled bit in the control field of event _before_
1394  * accessing the event control register. If a NMI hits, then it will
1395  * keep the event running.
1396  */
1397 void perf_event_task_sched_in(struct task_struct *task)
1398 {
1399         struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1400         struct perf_event_context *ctx = task->perf_event_ctxp;
1401
1402         if (likely(!ctx))
1403                 return;
1404
1405         if (cpuctx->task_ctx == ctx)
1406                 return;
1407
1408         /*
1409          * We want to keep the following priority order:
1410          * cpu pinned (that don't need to move), task pinned,
1411          * cpu flexible, task flexible.
1412          */
1413         cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
1414
1415         ctx_sched_in(ctx, cpuctx, EVENT_PINNED);
1416         cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
1417         ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE);
1418
1419         cpuctx->task_ctx = ctx;
1420 }
1421
1422 #define MAX_INTERRUPTS (~0ULL)
1423
1424 static void perf_log_throttle(struct perf_event *event, int enable);
1425
1426 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
1427 {
1428         u64 frequency = event->attr.sample_freq;
1429         u64 sec = NSEC_PER_SEC;
1430         u64 divisor, dividend;
1431
1432         int count_fls, nsec_fls, frequency_fls, sec_fls;
1433
1434         count_fls = fls64(count);
1435         nsec_fls = fls64(nsec);
1436         frequency_fls = fls64(frequency);
1437         sec_fls = 30;
1438
1439         /*
1440          * We got @count in @nsec, with a target of sample_freq HZ
1441          * the target period becomes:
1442          *
1443          *             @count * 10^9
1444          * period = -------------------
1445          *          @nsec * sample_freq
1446          *
1447          */
1448
1449         /*
1450          * Reduce accuracy by one bit such that @a and @b converge
1451          * to a similar magnitude.
1452          */
1453 #define REDUCE_FLS(a, b)                \
1454 do {                                    \
1455         if (a##_fls > b##_fls) {        \
1456                 a >>= 1;                \
1457                 a##_fls--;              \
1458         } else {                        \
1459                 b >>= 1;                \
1460                 b##_fls--;              \
1461         }                               \
1462 } while (0)
1463
1464         /*
1465          * Reduce accuracy until either term fits in a u64, then proceed with
1466          * the other, so that finally we can do a u64/u64 division.
1467          */
1468         while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
1469                 REDUCE_FLS(nsec, frequency);
1470                 REDUCE_FLS(sec, count);
1471         }
1472
1473         if (count_fls + sec_fls > 64) {
1474                 divisor = nsec * frequency;
1475
1476                 while (count_fls + sec_fls > 64) {
1477                         REDUCE_FLS(count, sec);
1478                         divisor >>= 1;
1479                 }
1480
1481                 dividend = count * sec;
1482         } else {
1483                 dividend = count * sec;
1484
1485                 while (nsec_fls + frequency_fls > 64) {
1486                         REDUCE_FLS(nsec, frequency);
1487                         dividend >>= 1;
1488                 }
1489
1490                 divisor = nsec * frequency;
1491         }
1492
1493         return div64_u64(dividend, divisor);
1494 }
1495
1496 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
1497 {
1498         struct hw_perf_event *hwc = &event->hw;
1499         u64 period, sample_period;
1500         s64 delta;
1501
1502         period = perf_calculate_period(event, nsec, count);
1503
1504         delta = (s64)(period - hwc->sample_period);
1505         delta = (delta + 7) / 8; /* low pass filter */
1506
1507         sample_period = hwc->sample_period + delta;
1508
1509         if (!sample_period)
1510                 sample_period = 1;
1511
1512         hwc->sample_period = sample_period;
1513
1514         if (atomic64_read(&hwc->period_left) > 8*sample_period) {
1515                 perf_disable();
1516                 event->pmu->disable(event);
1517                 atomic64_set(&hwc->period_left, 0);
1518                 event->pmu->enable(event);
1519                 perf_enable();
1520         }
1521 }
1522
1523 static void perf_ctx_adjust_freq(struct perf_event_context *ctx)
1524 {
1525         struct perf_event *event;
1526         struct hw_perf_event *hwc;
1527         u64 interrupts, now;
1528         s64 delta;
1529
1530         raw_spin_lock(&ctx->lock);
1531         list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
1532                 if (event->state != PERF_EVENT_STATE_ACTIVE)
1533                         continue;
1534
1535                 if (event->cpu != -1 && event->cpu != smp_processor_id())
1536                         continue;
1537
1538                 hwc = &event->hw;
1539
1540                 interrupts = hwc->interrupts;
1541                 hwc->interrupts = 0;
1542
1543                 /*
1544                  * unthrottle events on the tick
1545                  */
1546                 if (interrupts == MAX_INTERRUPTS) {
1547                         perf_log_throttle(event, 1);
1548                         event->pmu->unthrottle(event);
1549                 }
1550
1551                 if (!event->attr.freq || !event->attr.sample_freq)
1552                         continue;
1553
1554                 event->pmu->read(event);
1555                 now = atomic64_read(&event->count);
1556                 delta = now - hwc->freq_count_stamp;
1557                 hwc->freq_count_stamp = now;
1558
1559                 if (delta > 0)
1560                         perf_adjust_period(event, TICK_NSEC, delta);
1561         }
1562         raw_spin_unlock(&ctx->lock);
1563 }
1564
1565 /*
1566  * Round-robin a context's events:
1567  */
1568 static void rotate_ctx(struct perf_event_context *ctx)
1569 {
1570         if (!ctx->nr_events)
1571                 return;
1572
1573         raw_spin_lock(&ctx->lock);
1574
1575         /* Rotate the first entry last of non-pinned groups */
1576         perf_disable();
1577
1578         list_rotate_left(&ctx->flexible_groups);
1579
1580         perf_enable();
1581
1582         raw_spin_unlock(&ctx->lock);
1583 }
1584
1585 void perf_event_task_tick(struct task_struct *curr)
1586 {
1587         struct perf_cpu_context *cpuctx;
1588         struct perf_event_context *ctx;
1589
1590         if (!atomic_read(&nr_events))
1591                 return;
1592
1593         cpuctx = &__get_cpu_var(perf_cpu_context);
1594         ctx = curr->perf_event_ctxp;
1595
1596         perf_ctx_adjust_freq(&cpuctx->ctx);
1597         if (ctx)
1598                 perf_ctx_adjust_freq(ctx);
1599
1600         cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
1601         if (ctx)
1602                 task_ctx_sched_out(ctx, EVENT_FLEXIBLE);
1603
1604         rotate_ctx(&cpuctx->ctx);
1605         if (ctx)
1606                 rotate_ctx(ctx);
1607
1608         cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
1609         if (ctx)
1610                 task_ctx_sched_in(curr, EVENT_FLEXIBLE);
1611 }
1612
1613 static int event_enable_on_exec(struct perf_event *event,
1614                                 struct perf_event_context *ctx)
1615 {
1616         if (!event->attr.enable_on_exec)
1617                 return 0;
1618
1619         event->attr.enable_on_exec = 0;
1620         if (event->state >= PERF_EVENT_STATE_INACTIVE)
1621                 return 0;
1622
1623         __perf_event_mark_enabled(event, ctx);
1624
1625         return 1;
1626 }
1627
1628 /*
1629  * Enable all of a task's events that have been marked enable-on-exec.
1630  * This expects task == current.
1631  */
1632 static void perf_event_enable_on_exec(struct task_struct *task)
1633 {
1634         struct perf_event_context *ctx;
1635         struct perf_event *event;
1636         unsigned long flags;
1637         int enabled = 0;
1638         int ret;
1639
1640         local_irq_save(flags);
1641         ctx = task->perf_event_ctxp;
1642         if (!ctx || !ctx->nr_events)
1643                 goto out;
1644
1645         __perf_event_task_sched_out(ctx);
1646
1647         raw_spin_lock(&ctx->lock);
1648
1649         list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
1650                 ret = event_enable_on_exec(event, ctx);
1651                 if (ret)
1652                         enabled = 1;
1653         }
1654
1655         list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
1656                 ret = event_enable_on_exec(event, ctx);
1657                 if (ret)
1658                         enabled = 1;
1659         }
1660
1661         /*
1662          * Unclone this context if we enabled any event.
1663          */
1664         if (enabled)
1665                 unclone_ctx(ctx);
1666
1667         raw_spin_unlock(&ctx->lock);
1668
1669         perf_event_task_sched_in(task);
1670  out:
1671         local_irq_restore(flags);
1672 }
1673
1674 /*
1675  * Cross CPU call to read the hardware event
1676  */
1677 static void __perf_event_read(void *info)
1678 {
1679         struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1680         struct perf_event *event = info;
1681         struct perf_event_context *ctx = event->ctx;
1682
1683         /*
1684          * If this is a task context, we need to check whether it is
1685          * the current task context of this cpu.  If not it has been
1686          * scheduled out before the smp call arrived.  In that case
1687          * event->count would have been updated to a recent sample
1688          * when the event was scheduled out.
1689          */
1690         if (ctx->task && cpuctx->task_ctx != ctx)
1691                 return;
1692
1693         raw_spin_lock(&ctx->lock);
1694         update_context_time(ctx);
1695         update_event_times(event);
1696         raw_spin_unlock(&ctx->lock);
1697
1698         event->pmu->read(event);
1699 }
1700
1701 static u64 perf_event_read(struct perf_event *event)
1702 {
1703         /*
1704          * If event is enabled and currently active on a CPU, update the
1705          * value in the event structure:
1706          */
1707         if (event->state == PERF_EVENT_STATE_ACTIVE) {
1708                 smp_call_function_single(event->oncpu,
1709                                          __perf_event_read, event, 1);
1710         } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
1711                 struct perf_event_context *ctx = event->ctx;
1712                 unsigned long flags;
1713
1714                 raw_spin_lock_irqsave(&ctx->lock, flags);
1715                 update_context_time(ctx);
1716                 update_event_times(event);
1717                 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1718         }
1719
1720         return atomic64_read(&event->count);
1721 }
1722
1723 /*
1724  * Initialize the perf_event context in a task_struct:
1725  */
1726 static void
1727 __perf_event_init_context(struct perf_event_context *ctx,
1728                             struct task_struct *task)
1729 {
1730         raw_spin_lock_init(&ctx->lock);
1731         mutex_init(&ctx->mutex);
1732         INIT_LIST_HEAD(&ctx->pinned_groups);
1733         INIT_LIST_HEAD(&ctx->flexible_groups);
1734         INIT_LIST_HEAD(&ctx->event_list);
1735         atomic_set(&ctx->refcount, 1);
1736         ctx->task = task;
1737 }
1738
1739 static struct perf_event_context *find_get_context(pid_t pid, int cpu)
1740 {
1741         struct perf_event_context *ctx;
1742         struct perf_cpu_context *cpuctx;
1743         struct task_struct *task;
1744         unsigned long flags;
1745         int err;
1746
1747         if (pid == -1 && cpu != -1) {
1748                 /* Must be root to operate on a CPU event: */
1749                 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
1750                         return ERR_PTR(-EACCES);
1751
1752                 if (cpu < 0 || cpu >= nr_cpumask_bits)
1753                         return ERR_PTR(-EINVAL);
1754
1755                 /*
1756                  * We could be clever and allow to attach a event to an
1757                  * offline CPU and activate it when the CPU comes up, but
1758                  * that's for later.
1759                  */
1760                 if (!cpu_online(cpu))
1761                         return ERR_PTR(-ENODEV);
1762
1763                 cpuctx = &per_cpu(perf_cpu_context, cpu);
1764                 ctx = &cpuctx->ctx;
1765                 get_ctx(ctx);
1766
1767                 return ctx;
1768         }
1769
1770         rcu_read_lock();
1771         if (!pid)
1772                 task = current;
1773         else
1774                 task = find_task_by_vpid(pid);
1775         if (task)
1776                 get_task_struct(task);
1777         rcu_read_unlock();
1778
1779         if (!task)
1780                 return ERR_PTR(-ESRCH);
1781
1782         /*
1783          * Can't attach events to a dying task.
1784          */
1785         err = -ESRCH;
1786         if (task->flags & PF_EXITING)
1787                 goto errout;
1788
1789         /* Reuse ptrace permission checks for now. */
1790         err = -EACCES;
1791         if (!ptrace_may_access(task, PTRACE_MODE_READ))
1792                 goto errout;
1793
1794  retry:
1795         ctx = perf_lock_task_context(task, &flags);
1796         if (ctx) {
1797                 unclone_ctx(ctx);
1798                 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1799         }
1800
1801         if (!ctx) {
1802                 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
1803                 err = -ENOMEM;
1804                 if (!ctx)
1805                         goto errout;
1806                 __perf_event_init_context(ctx, task);
1807                 get_ctx(ctx);
1808                 if (cmpxchg(&task->perf_event_ctxp, NULL, ctx)) {
1809                         /*
1810                          * We raced with some other task; use
1811                          * the context they set.
1812                          */
1813                         kfree(ctx);
1814                         goto retry;
1815                 }
1816                 get_task_struct(task);
1817         }
1818
1819         put_task_struct(task);
1820         return ctx;
1821
1822  errout:
1823         put_task_struct(task);
1824         return ERR_PTR(err);
1825 }
1826
1827 static void perf_event_free_filter(struct perf_event *event);
1828
1829 static void free_event_rcu(struct rcu_head *head)
1830 {
1831         struct perf_event *event;
1832
1833         event = container_of(head, struct perf_event, rcu_head);
1834         if (event->ns)
1835                 put_pid_ns(event->ns);
1836         perf_event_free_filter(event);
1837         kfree(event);
1838 }
1839
1840 static void perf_pending_sync(struct perf_event *event);
1841
1842 static void free_event(struct perf_event *event)
1843 {
1844         perf_pending_sync(event);
1845
1846         if (!event->parent) {
1847                 atomic_dec(&nr_events);
1848                 if (event->attr.mmap)
1849                         atomic_dec(&nr_mmap_events);
1850                 if (event->attr.comm)
1851                         atomic_dec(&nr_comm_events);
1852                 if (event->attr.task)
1853                         atomic_dec(&nr_task_events);
1854         }
1855
1856         if (event->output) {
1857                 fput(event->output->filp);
1858                 event->output = NULL;
1859         }
1860
1861         if (event->destroy)
1862                 event->destroy(event);
1863
1864         put_ctx(event->ctx);
1865         call_rcu(&event->rcu_head, free_event_rcu);
1866 }
1867
1868 int perf_event_release_kernel(struct perf_event *event)
1869 {
1870         struct perf_event_context *ctx = event->ctx;
1871
1872         WARN_ON_ONCE(ctx->parent_ctx);
1873         mutex_lock(&ctx->mutex);
1874         perf_event_remove_from_context(event);
1875         mutex_unlock(&ctx->mutex);
1876
1877         mutex_lock(&event->owner->perf_event_mutex);
1878         list_del_init(&event->owner_entry);
1879         mutex_unlock(&event->owner->perf_event_mutex);
1880         put_task_struct(event->owner);
1881
1882         free_event(event);
1883
1884         return 0;
1885 }
1886 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
1887
1888 /*
1889  * Called when the last reference to the file is gone.
1890  */
1891 static int perf_release(struct inode *inode, struct file *file)
1892 {
1893         struct perf_event *event = file->private_data;
1894
1895         file->private_data = NULL;
1896
1897         return perf_event_release_kernel(event);
1898 }
1899
1900 static int perf_event_read_size(struct perf_event *event)
1901 {
1902         int entry = sizeof(u64); /* value */
1903         int size = 0;
1904         int nr = 1;
1905
1906         if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1907                 size += sizeof(u64);
1908
1909         if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1910                 size += sizeof(u64);
1911
1912         if (event->attr.read_format & PERF_FORMAT_ID)
1913                 entry += sizeof(u64);
1914
1915         if (event->attr.read_format & PERF_FORMAT_GROUP) {
1916                 nr += event->group_leader->nr_siblings;
1917                 size += sizeof(u64);
1918         }
1919
1920         size += entry * nr;
1921
1922         return size;
1923 }
1924
1925 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
1926 {
1927         struct perf_event *child;
1928         u64 total = 0;
1929
1930         *enabled = 0;
1931         *running = 0;
1932
1933         mutex_lock(&event->child_mutex);
1934         total += perf_event_read(event);
1935         *enabled += event->total_time_enabled +
1936                         atomic64_read(&event->child_total_time_enabled);
1937         *running += event->total_time_running +
1938                         atomic64_read(&event->child_total_time_running);
1939
1940         list_for_each_entry(child, &event->child_list, child_list) {
1941                 total += perf_event_read(child);
1942                 *enabled += child->total_time_enabled;
1943                 *running += child->total_time_running;
1944         }
1945         mutex_unlock(&event->child_mutex);
1946
1947         return total;
1948 }
1949 EXPORT_SYMBOL_GPL(perf_event_read_value);
1950
1951 static int perf_event_read_group(struct perf_event *event,
1952                                    u64 read_format, char __user *buf)
1953 {
1954         struct perf_event *leader = event->group_leader, *sub;
1955         int n = 0, size = 0, ret = -EFAULT;
1956         struct perf_event_context *ctx = leader->ctx;
1957         u64 values[5];
1958         u64 count, enabled, running;
1959
1960         mutex_lock(&ctx->mutex);
1961         count = perf_event_read_value(leader, &enabled, &running);
1962
1963         values[n++] = 1 + leader->nr_siblings;
1964         if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1965                 values[n++] = enabled;
1966         if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1967                 values[n++] = running;
1968         values[n++] = count;
1969         if (read_format & PERF_FORMAT_ID)
1970                 values[n++] = primary_event_id(leader);
1971
1972         size = n * sizeof(u64);
1973
1974         if (copy_to_user(buf, values, size))
1975                 goto unlock;
1976
1977         ret = size;
1978
1979         list_for_each_entry(sub, &leader->sibling_list, group_entry) {
1980                 n = 0;
1981
1982                 values[n++] = perf_event_read_value(sub, &enabled, &running);
1983                 if (read_format & PERF_FORMAT_ID)
1984                         values[n++] = primary_event_id(sub);
1985
1986                 size = n * sizeof(u64);
1987
1988                 if (copy_to_user(buf + ret, values, size)) {
1989                         ret = -EFAULT;
1990                         goto unlock;
1991                 }
1992
1993                 ret += size;
1994         }
1995 unlock:
1996         mutex_unlock(&ctx->mutex);
1997
1998         return ret;
1999 }
2000
2001 static int perf_event_read_one(struct perf_event *event,
2002                                  u64 read_format, char __user *buf)
2003 {
2004         u64 enabled, running;
2005         u64 values[4];
2006         int n = 0;
2007
2008         values[n++] = perf_event_read_value(event, &enabled, &running);
2009         if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
2010                 values[n++] = enabled;
2011         if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
2012                 values[n++] = running;
2013         if (read_format & PERF_FORMAT_ID)
2014                 values[n++] = primary_event_id(event);
2015
2016         if (copy_to_user(buf, values, n * sizeof(u64)))
2017                 return -EFAULT;
2018
2019         return n * sizeof(u64);
2020 }
2021
2022 /*
2023  * Read the performance event - simple non blocking version for now
2024  */
2025 static ssize_t
2026 perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
2027 {
2028         u64 read_format = event->attr.read_format;
2029         int ret;
2030
2031         /*
2032          * Return end-of-file for a read on a event that is in
2033          * error state (i.e. because it was pinned but it couldn't be
2034          * scheduled on to the CPU at some point).
2035          */
2036         if (event->state == PERF_EVENT_STATE_ERROR)
2037                 return 0;
2038
2039         if (count < perf_event_read_size(event))
2040                 return -ENOSPC;
2041
2042         WARN_ON_ONCE(event->ctx->parent_ctx);
2043         if (read_format & PERF_FORMAT_GROUP)
2044                 ret = perf_event_read_group(event, read_format, buf);
2045         else
2046                 ret = perf_event_read_one(event, read_format, buf);
2047
2048         return ret;
2049 }
2050
2051 static ssize_t
2052 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
2053 {
2054         struct perf_event *event = file->private_data;
2055
2056         return perf_read_hw(event, buf, count);
2057 }
2058
2059 static unsigned int perf_poll(struct file *file, poll_table *wait)
2060 {
2061         struct perf_event *event = file->private_data;
2062         struct perf_mmap_data *data;
2063         unsigned int events = POLL_HUP;
2064
2065         rcu_read_lock();
2066         data = rcu_dereference(event->data);
2067         if (data)
2068                 events = atomic_xchg(&data->poll, 0);
2069         rcu_read_unlock();
2070
2071         poll_wait(file, &event->waitq, wait);
2072
2073         return events;
2074 }
2075
2076 static void perf_event_reset(struct perf_event *event)
2077 {
2078         (void)perf_event_read(event);
2079         atomic64_set(&event->count, 0);
2080         perf_event_update_userpage(event);
2081 }
2082
2083 /*
2084  * Holding the top-level event's child_mutex means that any
2085  * descendant process that has inherited this event will block
2086  * in sync_child_event if it goes to exit, thus satisfying the
2087  * task existence requirements of perf_event_enable/disable.
2088  */
2089 static void perf_event_for_each_child(struct perf_event *event,
2090                                         void (*func)(struct perf_event *))
2091 {
2092         struct perf_event *child;
2093
2094         WARN_ON_ONCE(event->ctx->parent_ctx);
2095         mutex_lock(&event->child_mutex);
2096         func(event);
2097         list_for_each_entry(child, &event->child_list, child_list)
2098                 func(child);
2099         mutex_unlock(&event->child_mutex);
2100 }
2101
2102 static void perf_event_for_each(struct perf_event *event,
2103                                   void (*func)(struct perf_event *))
2104 {
2105         struct perf_event_context *ctx = event->ctx;
2106         struct perf_event *sibling;
2107
2108         WARN_ON_ONCE(ctx->parent_ctx);
2109         mutex_lock(&ctx->mutex);
2110         event = event->group_leader;
2111
2112         perf_event_for_each_child(event, func);
2113         func(event);
2114         list_for_each_entry(sibling, &event->sibling_list, group_entry)
2115                 perf_event_for_each_child(event, func);
2116         mutex_unlock(&ctx->mutex);
2117 }
2118
2119 static int perf_event_period(struct perf_event *event, u64 __user *arg)
2120 {
2121         struct perf_event_context *ctx = event->ctx;
2122         unsigned long size;
2123         int ret = 0;
2124         u64 value;
2125
2126         if (!event->attr.sample_period)
2127                 return -EINVAL;
2128
2129         size = copy_from_user(&value, arg, sizeof(value));
2130         if (size != sizeof(value))
2131                 return -EFAULT;
2132
2133         if (!value)
2134                 return -EINVAL;
2135
2136         raw_spin_lock_irq(&ctx->lock);
2137         if (event->attr.freq) {
2138                 if (value > sysctl_perf_event_sample_rate) {
2139                         ret = -EINVAL;
2140                         goto unlock;
2141                 }
2142
2143                 event->attr.sample_freq = value;
2144         } else {
2145                 event->attr.sample_period = value;
2146                 event->hw.sample_period = value;
2147         }
2148 unlock:
2149         raw_spin_unlock_irq(&ctx->lock);
2150
2151         return ret;
2152 }
2153
2154 static int perf_event_set_output(struct perf_event *event, int output_fd);
2155 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
2156
2157 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2158 {
2159         struct perf_event *event = file->private_data;
2160         void (*func)(struct perf_event *);
2161         u32 flags = arg;
2162
2163         switch (cmd) {
2164         case PERF_EVENT_IOC_ENABLE:
2165                 func = perf_event_enable;
2166                 break;
2167         case PERF_EVENT_IOC_DISABLE:
2168                 func = perf_event_disable;
2169                 break;
2170         case PERF_EVENT_IOC_RESET:
2171                 func = perf_event_reset;
2172                 break;
2173
2174         case PERF_EVENT_IOC_REFRESH:
2175                 return perf_event_refresh(event, arg);
2176
2177         case PERF_EVENT_IOC_PERIOD:
2178                 return perf_event_period(event, (u64 __user *)arg);
2179
2180         case PERF_EVENT_IOC_SET_OUTPUT:
2181                 return perf_event_set_output(event, arg);
2182
2183         case PERF_EVENT_IOC_SET_FILTER:
2184                 return perf_event_set_filter(event, (void __user *)arg);
2185
2186         default:
2187                 return -ENOTTY;
2188         }
2189
2190         if (flags & PERF_IOC_FLAG_GROUP)
2191                 perf_event_for_each(event, func);
2192         else
2193                 perf_event_for_each_child(event, func);
2194
2195         return 0;
2196 }
2197
2198 int perf_event_task_enable(void)
2199 {
2200         struct perf_event *event;
2201
2202         mutex_lock(&current->perf_event_mutex);
2203         list_for_each_entry(event, &current->perf_event_list, owner_entry)
2204                 perf_event_for_each_child(event, perf_event_enable);
2205         mutex_unlock(&current->perf_event_mutex);
2206
2207         return 0;
2208 }
2209
2210 int perf_event_task_disable(void)
2211 {
2212         struct perf_event *event;
2213
2214         mutex_lock(&current->perf_event_mutex);
2215         list_for_each_entry(event, &current->perf_event_list, owner_entry)
2216                 perf_event_for_each_child(event, perf_event_disable);
2217         mutex_unlock(&current->perf_event_mutex);
2218
2219         return 0;
2220 }
2221
2222 #ifndef PERF_EVENT_INDEX_OFFSET
2223 # define PERF_EVENT_INDEX_OFFSET 0
2224 #endif
2225
2226 static int perf_event_index(struct perf_event *event)
2227 {
2228         if (event->state != PERF_EVENT_STATE_ACTIVE)
2229                 return 0;
2230
2231         return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET;
2232 }
2233
2234 /*
2235  * Callers need to ensure there can be no nesting of this function, otherwise
2236  * the seqlock logic goes bad. We can not serialize this because the arch
2237  * code calls this from NMI context.
2238  */
2239 void perf_event_update_userpage(struct perf_event *event)
2240 {
2241         struct perf_event_mmap_page *userpg;
2242         struct perf_mmap_data *data;
2243
2244         rcu_read_lock();
2245         data = rcu_dereference(event->data);
2246         if (!data)
2247                 goto unlock;
2248
2249         userpg = data->user_page;
2250
2251         /*
2252          * Disable preemption so as to not let the corresponding user-space
2253          * spin too long if we get preempted.
2254          */
2255         preempt_disable();
2256         ++userpg->lock;
2257         barrier();
2258         userpg->index = perf_event_index(event);
2259         userpg->offset = atomic64_read(&event->count);
2260         if (event->state == PERF_EVENT_STATE_ACTIVE)
2261                 userpg->offset -= atomic64_read(&event->hw.prev_count);
2262
2263         userpg->time_enabled = event->total_time_enabled +
2264                         atomic64_read(&event->child_total_time_enabled);
2265
2266         userpg->time_running = event->total_time_running +
2267                         atomic64_read(&event->child_total_time_running);
2268
2269         barrier();
2270         ++userpg->lock;
2271         preempt_enable();
2272 unlock:
2273         rcu_read_unlock();
2274 }
2275
2276 static unsigned long perf_data_size(struct perf_mmap_data *data)
2277 {
2278         return data->nr_pages << (PAGE_SHIFT + data->data_order);
2279 }
2280
2281 #ifndef CONFIG_PERF_USE_VMALLOC
2282
2283 /*
2284  * Back perf_mmap() with regular GFP_KERNEL-0 pages.
2285  */
2286
2287 static struct page *
2288 perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff)
2289 {
2290         if (pgoff > data->nr_pages)
2291                 return NULL;
2292
2293         if (pgoff == 0)
2294                 return virt_to_page(data->user_page);
2295
2296         return virt_to_page(data->data_pages[pgoff - 1]);
2297 }
2298
2299 static struct perf_mmap_data *
2300 perf_mmap_data_alloc(struct perf_event *event, int nr_pages)
2301 {
2302         struct perf_mmap_data *data;
2303         unsigned long size;
2304         int i;
2305
2306         WARN_ON(atomic_read(&event->mmap_count));
2307
2308         size = sizeof(struct perf_mmap_data);
2309         size += nr_pages * sizeof(void *);
2310
2311         data = kzalloc(size, GFP_KERNEL);
2312         if (!data)
2313                 goto fail;
2314
2315         data->user_page = (void *)get_zeroed_page(GFP_KERNEL);
2316         if (!data->user_page)
2317                 goto fail_user_page;
2318
2319         for (i = 0; i < nr_pages; i++) {
2320                 data->data_pages[i] = (void *)get_zeroed_page(GFP_KERNEL);
2321                 if (!data->data_pages[i])
2322                         goto fail_data_pages;
2323         }
2324
2325         data->data_order = 0;
2326         data->nr_pages = nr_pages;
2327
2328         return data;
2329
2330 fail_data_pages:
2331         for (i--; i >= 0; i--)
2332                 free_page((unsigned long)data->data_pages[i]);
2333
2334         free_page((unsigned long)data->user_page);
2335
2336 fail_user_page:
2337         kfree(data);
2338
2339 fail:
2340         return NULL;
2341 }
2342
2343 static void perf_mmap_free_page(unsigned long addr)
2344 {
2345         struct page *page = virt_to_page((void *)addr);
2346
2347         page->mapping = NULL;
2348         __free_page(page);
2349 }
2350
2351 static void perf_mmap_data_free(struct perf_mmap_data *data)
2352 {
2353         int i;
2354
2355         perf_mmap_free_page((unsigned long)data->user_page);
2356         for (i = 0; i < data->nr_pages; i++)
2357                 perf_mmap_free_page((unsigned long)data->data_pages[i]);
2358         kfree(data);
2359 }
2360
2361 #else
2362
2363 /*
2364  * Back perf_mmap() with vmalloc memory.
2365  *
2366  * Required for architectures that have d-cache aliasing issues.
2367  */
2368
2369 static struct page *
2370 perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff)
2371 {
2372         if (pgoff > (1UL << data->data_order))
2373                 return NULL;
2374
2375         return vmalloc_to_page((void *)data->user_page + pgoff * PAGE_SIZE);
2376 }
2377
2378 static void perf_mmap_unmark_page(void *addr)
2379 {
2380         struct page *page = vmalloc_to_page(addr);
2381
2382         page->mapping = NULL;
2383 }
2384
2385 static void perf_mmap_data_free_work(struct work_struct *work)
2386 {
2387         struct perf_mmap_data *data;
2388         void *base;
2389         int i, nr;
2390
2391         data = container_of(work, struct perf_mmap_data, work);
2392         nr = 1 << data->data_order;
2393
2394         base = data->user_page;
2395         for (i = 0; i < nr + 1; i++)
2396                 perf_mmap_unmark_page(base + (i * PAGE_SIZE));
2397
2398         vfree(base);
2399         kfree(data);
2400 }
2401
2402 static void perf_mmap_data_free(struct perf_mmap_data *data)
2403 {
2404         schedule_work(&data->work);
2405 }
2406
2407 static struct perf_mmap_data *
2408 perf_mmap_data_alloc(struct perf_event *event, int nr_pages)
2409 {
2410         struct perf_mmap_data *data;
2411         unsigned long size;
2412         void *all_buf;
2413
2414         WARN_ON(atomic_read(&event->mmap_count));
2415
2416         size = sizeof(struct perf_mmap_data);
2417         size += sizeof(void *);
2418
2419         data = kzalloc(size, GFP_KERNEL);
2420         if (!data)
2421                 goto fail;
2422
2423         INIT_WORK(&data->work, perf_mmap_data_free_work);
2424
2425         all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
2426         if (!all_buf)
2427                 goto fail_all_buf;
2428
2429         data->user_page = all_buf;
2430         data->data_pages[0] = all_buf + PAGE_SIZE;
2431         data->data_order = ilog2(nr_pages);
2432         data->nr_pages = 1;
2433
2434         return data;
2435
2436 fail_all_buf:
2437         kfree(data);
2438
2439 fail:
2440         return NULL;
2441 }
2442
2443 #endif
2444
2445 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2446 {
2447         struct perf_event *event = vma->vm_file->private_data;
2448         struct perf_mmap_data *data;
2449         int ret = VM_FAULT_SIGBUS;
2450
2451         if (vmf->flags & FAULT_FLAG_MKWRITE) {
2452                 if (vmf->pgoff == 0)
2453                         ret = 0;
2454                 return ret;
2455         }
2456
2457         rcu_read_lock();
2458         data = rcu_dereference(event->data);
2459         if (!data)
2460                 goto unlock;
2461
2462         if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
2463                 goto unlock;
2464
2465         vmf->page = perf_mmap_to_page(data, vmf->pgoff);
2466         if (!vmf->page)
2467                 goto unlock;
2468
2469         get_page(vmf->page);
2470         vmf->page->mapping = vma->vm_file->f_mapping;
2471         vmf->page->index   = vmf->pgoff;
2472
2473         ret = 0;
2474 unlock:
2475         rcu_read_unlock();
2476
2477         return ret;
2478 }
2479
2480 static void
2481 perf_mmap_data_init(struct perf_event *event, struct perf_mmap_data *data)
2482 {
2483         long max_size = perf_data_size(data);
2484
2485         atomic_set(&data->lock, -1);
2486
2487         if (event->attr.watermark) {
2488                 data->watermark = min_t(long, max_size,
2489                                         event->attr.wakeup_watermark);
2490         }
2491
2492         if (!data->watermark)
2493                 data->watermark = max_size / 2;
2494
2495
2496         rcu_assign_pointer(event->data, data);
2497 }
2498
2499 static void perf_mmap_data_free_rcu(struct rcu_head *rcu_head)
2500 {
2501         struct perf_mmap_data *data;
2502
2503         data = container_of(rcu_head, struct perf_mmap_data, rcu_head);
2504         perf_mmap_data_free(data);
2505 }
2506
2507 static void perf_mmap_data_release(struct perf_event *event)
2508 {
2509         struct perf_mmap_data *data = event->data;
2510
2511         WARN_ON(atomic_read(&event->mmap_count));
2512
2513         rcu_assign_pointer(event->data, NULL);
2514         call_rcu(&data->rcu_head, perf_mmap_data_free_rcu);
2515 }
2516
2517 static void perf_mmap_open(struct vm_area_struct *vma)
2518 {
2519         struct perf_event *event = vma->vm_file->private_data;
2520
2521         atomic_inc(&event->mmap_count);
2522 }
2523
2524 static void perf_mmap_close(struct vm_area_struct *vma)
2525 {
2526         struct perf_event *event = vma->vm_file->private_data;
2527
2528         WARN_ON_ONCE(event->ctx->parent_ctx);
2529         if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
2530                 unsigned long size = perf_data_size(event->data);
2531                 struct user_struct *user = current_user();
2532
2533                 atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
2534                 vma->vm_mm->locked_vm -= event->data->nr_locked;
2535                 perf_mmap_data_release(event);
2536                 mutex_unlock(&event->mmap_mutex);
2537         }
2538 }
2539
2540 static const struct vm_operations_struct perf_mmap_vmops = {
2541         .open           = perf_mmap_open,
2542         .close          = perf_mmap_close,
2543         .fault          = perf_mmap_fault,
2544         .page_mkwrite   = perf_mmap_fault,
2545 };
2546
2547 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
2548 {
2549         struct perf_event *event = file->private_data;
2550         unsigned long user_locked, user_lock_limit;
2551         struct user_struct *user = current_user();
2552         unsigned long locked, lock_limit;
2553         struct perf_mmap_data *data;
2554         unsigned long vma_size;
2555         unsigned long nr_pages;
2556         long user_extra, extra;
2557         int ret = 0;
2558
2559         if (!(vma->vm_flags & VM_SHARED))
2560                 return -EINVAL;
2561
2562         vma_size = vma->vm_end - vma->vm_start;
2563         nr_pages = (vma_size / PAGE_SIZE) - 1;
2564
2565         /*
2566          * If we have data pages ensure they're a power-of-two number, so we
2567          * can do bitmasks instead of modulo.
2568          */
2569         if (nr_pages != 0 && !is_power_of_2(nr_pages))
2570                 return -EINVAL;
2571
2572         if (vma_size != PAGE_SIZE * (1 + nr_pages))
2573                 return -EINVAL;
2574
2575         if (vma->vm_pgoff != 0)
2576                 return -EINVAL;
2577
2578         WARN_ON_ONCE(event->ctx->parent_ctx);
2579         mutex_lock(&event->mmap_mutex);
2580         if (event->output) {
2581                 ret = -EINVAL;
2582                 goto unlock;
2583         }
2584
2585         if (atomic_inc_not_zero(&event->mmap_count)) {
2586                 if (nr_pages != event->data->nr_pages)
2587                         ret = -EINVAL;
2588                 goto unlock;
2589         }
2590
2591         user_extra = nr_pages + 1;
2592         user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
2593
2594         /*
2595          * Increase the limit linearly with more CPUs:
2596          */
2597         user_lock_limit *= num_online_cpus();
2598
2599         user_locked = atomic_long_read(&user->locked_vm) + user_extra;
2600
2601         extra = 0;
2602         if (user_locked > user_lock_limit)
2603                 extra = user_locked - user_lock_limit;
2604
2605         lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
2606         lock_limit >>= PAGE_SHIFT;
2607         locked = vma->vm_mm->locked_vm + extra;
2608
2609         if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
2610                 !capable(CAP_IPC_LOCK)) {
2611                 ret = -EPERM;
2612                 goto unlock;
2613         }
2614
2615         WARN_ON(event->data);
2616
2617         data = perf_mmap_data_alloc(event, nr_pages);
2618         ret = -ENOMEM;
2619         if (!data)
2620                 goto unlock;
2621
2622         ret = 0;
2623         perf_mmap_data_init(event, data);
2624
2625         atomic_set(&event->mmap_count, 1);
2626         atomic_long_add(user_extra, &user->locked_vm);
2627         vma->vm_mm->locked_vm += extra;
2628         event->data->nr_locked = extra;
2629         if (vma->vm_flags & VM_WRITE)
2630                 event->data->writable = 1;
2631
2632 unlock:
2633         mutex_unlock(&event->mmap_mutex);
2634
2635         vma->vm_flags |= VM_RESERVED;
2636         vma->vm_ops = &perf_mmap_vmops;
2637
2638         return ret;
2639 }
2640
2641 static int perf_fasync(int fd, struct file *filp, int on)
2642 {
2643         struct inode *inode = filp->f_path.dentry->d_inode;
2644         struct perf_event *event = filp->private_data;
2645         int retval;
2646
2647         mutex_lock(&inode->i_mutex);
2648         retval = fasync_helper(fd, filp, on, &event->fasync);
2649         mutex_unlock(&inode->i_mutex);
2650
2651         if (retval < 0)
2652                 return retval;
2653
2654         return 0;
2655 }
2656
2657 static const struct file_operations perf_fops = {
2658         .release                = perf_release,
2659         .read                   = perf_read,
2660         .poll                   = perf_poll,
2661         .unlocked_ioctl         = perf_ioctl,
2662         .compat_ioctl           = perf_ioctl,
2663         .mmap                   = perf_mmap,
2664         .fasync                 = perf_fasync,
2665 };
2666
2667 /*
2668  * Perf event wakeup
2669  *
2670  * If there's data, ensure we set the poll() state and publish everything
2671  * to user-space before waking everybody up.
2672  */
2673
2674 void perf_event_wakeup(struct perf_event *event)
2675 {
2676         wake_up_all(&event->waitq);
2677
2678         if (event->pending_kill) {
2679                 kill_fasync(&event->fasync, SIGIO, event->pending_kill);
2680                 event->pending_kill = 0;
2681         }
2682 }
2683
2684 /*
2685  * Pending wakeups
2686  *
2687  * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
2688  *
2689  * The NMI bit means we cannot possibly take locks. Therefore, maintain a
2690  * single linked list and use cmpxchg() to add entries lockless.
2691  */
2692
2693 static void perf_pending_event(struct perf_pending_entry *entry)
2694 {
2695         struct perf_event *event = container_of(entry,
2696                         struct perf_event, pending);
2697
2698         if (event->pending_disable) {
2699                 event->pending_disable = 0;
2700                 __perf_event_disable(event);
2701         }
2702
2703         if (event->pending_wakeup) {
2704                 event->pending_wakeup = 0;
2705                 perf_event_wakeup(event);
2706         }
2707 }
2708
2709 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
2710
2711 static DEFINE_PER_CPU(struct perf_pending_entry *, perf_pending_head) = {
2712         PENDING_TAIL,
2713 };
2714
2715 static void perf_pending_queue(struct perf_pending_entry *entry,
2716                                void (*func)(struct perf_pending_entry *))
2717 {
2718         struct perf_pending_entry **head;
2719
2720         if (cmpxchg(&entry->next, NULL, PENDING_TAIL) != NULL)
2721                 return;
2722
2723         entry->func = func;
2724
2725         head = &get_cpu_var(perf_pending_head);
2726
2727         do {
2728                 entry->next = *head;
2729         } while (cmpxchg(head, entry->next, entry) != entry->next);
2730
2731         set_perf_event_pending();
2732
2733         put_cpu_var(perf_pending_head);
2734 }
2735
2736 static int __perf_pending_run(void)
2737 {
2738         struct perf_pending_entry *list;
2739         int nr = 0;
2740
2741         list = xchg(&__get_cpu_var(perf_pending_head), PENDING_TAIL);
2742         while (list != PENDING_TAIL) {
2743                 void (*func)(struct perf_pending_entry *);
2744                 struct perf_pending_entry *entry = list;
2745
2746                 list = list->next;
2747
2748                 func = entry->func;
2749                 entry->next = NULL;
2750                 /*
2751                  * Ensure we observe the unqueue before we issue the wakeup,
2752                  * so that we won't be waiting forever.
2753                  * -- see perf_not_pending().
2754                  */
2755                 smp_wmb();
2756
2757                 func(entry);
2758                 nr++;
2759         }
2760
2761         return nr;
2762 }
2763
2764 static inline int perf_not_pending(struct perf_event *event)
2765 {
2766         /*
2767          * If we flush on whatever cpu we run, there is a chance we don't
2768          * need to wait.
2769          */
2770         get_cpu();
2771         __perf_pending_run();
2772         put_cpu();
2773
2774         /*
2775          * Ensure we see the proper queue state before going to sleep
2776          * so that we do not miss the wakeup. -- see perf_pending_handle()
2777          */
2778         smp_rmb();
2779         return event->pending.next == NULL;
2780 }
2781
2782 static void perf_pending_sync(struct perf_event *event)
2783 {
2784         wait_event(event->waitq, perf_not_pending(event));
2785 }
2786
2787 void perf_event_do_pending(void)
2788 {
2789         __perf_pending_run();
2790 }
2791
2792 /*
2793  * Callchain support -- arch specific
2794  */
2795
2796 __weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
2797 {
2798         return NULL;
2799 }
2800
2801 /*
2802  * Output
2803  */
2804 static bool perf_output_space(struct perf_mmap_data *data, unsigned long tail,
2805                               unsigned long offset, unsigned long head)
2806 {
2807         unsigned long mask;
2808
2809         if (!data->writable)
2810                 return true;
2811
2812         mask = perf_data_size(data) - 1;
2813
2814         offset = (offset - tail) & mask;
2815         head   = (head   - tail) & mask;
2816
2817         if ((int)(head - offset) < 0)
2818                 return false;
2819
2820         return true;
2821 }
2822
2823 static void perf_output_wakeup(struct perf_output_handle *handle)
2824 {
2825         atomic_set(&handle->data->poll, POLL_IN);
2826
2827         if (handle->nmi) {
2828                 handle->event->pending_wakeup = 1;
2829                 perf_pending_queue(&handle->event->pending,
2830                                    perf_pending_event);
2831         } else
2832                 perf_event_wakeup(handle->event);
2833 }
2834
2835 /*
2836  * Curious locking construct.
2837  *
2838  * We need to ensure a later event_id doesn't publish a head when a former
2839  * event_id isn't done writing. However since we need to deal with NMIs we
2840  * cannot fully serialize things.
2841  *
2842  * What we do is serialize between CPUs so we only have to deal with NMI
2843  * nesting on a single CPU.
2844  *
2845  * We only publish the head (and generate a wakeup) when the outer-most
2846  * event_id completes.
2847  */
2848 static void perf_output_lock(struct perf_output_handle *handle)
2849 {
2850         struct perf_mmap_data *data = handle->data;
2851         int cur, cpu = get_cpu();
2852
2853         handle->locked = 0;
2854
2855         for (;;) {
2856                 cur = atomic_cmpxchg(&data->lock, -1, cpu);
2857                 if (cur == -1) {
2858                         handle->locked = 1;
2859                         break;
2860                 }
2861                 if (cur == cpu)
2862                         break;
2863
2864                 cpu_relax();
2865         }
2866 }
2867
2868 static void perf_output_unlock(struct perf_output_handle *handle)
2869 {
2870         struct perf_mmap_data *data = handle->data;
2871         unsigned long head;
2872         int cpu;
2873
2874         data->done_head = data->head;
2875
2876         if (!handle->locked)
2877                 goto out;
2878
2879 again:
2880         /*
2881          * The xchg implies a full barrier that ensures all writes are done
2882          * before we publish the new head, matched by a rmb() in userspace when
2883          * reading this position.
2884          */
2885         while ((head = atomic_long_xchg(&data->done_head, 0)))
2886                 data->user_page->data_head = head;
2887
2888         /*
2889          * NMI can happen here, which means we can miss a done_head update.
2890          */
2891
2892         cpu = atomic_xchg(&data->lock, -1);
2893         WARN_ON_ONCE(cpu != smp_processor_id());
2894
2895         /*
2896          * Therefore we have to validate we did not indeed do so.
2897          */
2898         if (unlikely(atomic_long_read(&data->done_head))) {
2899                 /*
2900                  * Since we had it locked, we can lock it again.
2901                  */
2902                 while (atomic_cmpxchg(&data->lock, -1, cpu) != -1)
2903                         cpu_relax();
2904
2905                 goto again;
2906         }
2907
2908         if (atomic_xchg(&data->wakeup, 0))
2909                 perf_output_wakeup(handle);
2910 out:
2911         put_cpu();
2912 }
2913
2914 void perf_output_copy(struct perf_output_handle *handle,
2915                       const void *buf, unsigned int len)
2916 {
2917         unsigned int pages_mask;
2918         unsigned long offset;
2919         unsigned int size;
2920         void **pages;
2921
2922         offset          = handle->offset;
2923         pages_mask      = handle->data->nr_pages - 1;
2924         pages           = handle->data->data_pages;
2925
2926         do {
2927                 unsigned long page_offset;
2928                 unsigned long page_size;
2929                 int nr;
2930
2931                 nr          = (offset >> PAGE_SHIFT) & pages_mask;
2932                 page_size   = 1UL << (handle->data->data_order + PAGE_SHIFT);
2933                 page_offset = offset & (page_size - 1);
2934                 size        = min_t(unsigned int, page_size - page_offset, len);
2935
2936                 memcpy(pages[nr] + page_offset, buf, size);
2937
2938                 len         -= size;
2939                 buf         += size;
2940                 offset      += size;
2941         } while (len);
2942
2943         handle->offset = offset;
2944
2945         /*
2946          * Check we didn't copy past our reservation window, taking the
2947          * possible unsigned int wrap into account.
2948          */
2949         WARN_ON_ONCE(((long)(handle->head - handle->offset)) < 0);
2950 }
2951
2952 int perf_output_begin(struct perf_output_handle *handle,
2953                       struct perf_event *event, unsigned int size,
2954                       int nmi, int sample)
2955 {
2956         struct perf_event *output_event;
2957         struct perf_mmap_data *data;
2958         unsigned long tail, offset, head;
2959         int have_lost;
2960         struct {
2961                 struct perf_event_header header;
2962                 u64                      id;
2963                 u64                      lost;
2964         } lost_event;
2965
2966         rcu_read_lock();
2967         /*
2968          * For inherited events we send all the output towards the parent.
2969          */
2970         if (event->parent)
2971                 event = event->parent;
2972
2973         output_event = rcu_dereference(event->output);
2974         if (output_event)
2975                 event = output_event;
2976
2977         data = rcu_dereference(event->data);
2978         if (!data)
2979                 goto out;
2980
2981         handle->data    = data;
2982         handle->event   = event;
2983         handle->nmi     = nmi;
2984         handle->sample  = sample;
2985
2986         if (!data->nr_pages)
2987                 goto fail;
2988
2989         have_lost = atomic_read(&data->lost);
2990         if (have_lost)
2991                 size += sizeof(lost_event);
2992
2993         perf_output_lock(handle);
2994
2995         do {
2996                 /*
2997                  * Userspace could choose to issue a mb() before updating the
2998                  * tail pointer. So that all reads will be completed before the
2999                  * write is issued.
3000                  */
3001                 tail = ACCESS_ONCE(data->user_page->data_tail);
3002                 smp_rmb();
3003                 offset = head = atomic_long_read(&data->head);
3004                 head += size;
3005                 if (unlikely(!perf_output_space(data, tail, offset, head)))
3006                         goto fail;
3007         } while (atomic_long_cmpxchg(&data->head, offset, head) != offset);
3008
3009         handle->offset  = offset;
3010         handle->head    = head;
3011
3012         if (head - tail > data->watermark)
3013                 atomic_set(&data->wakeup, 1);
3014
3015         if (have_lost) {
3016                 lost_event.header.type = PERF_RECORD_LOST;
3017                 lost_event.header.misc = 0;
3018                 lost_event.header.size = sizeof(lost_event);
3019                 lost_event.id          = event->id;
3020                 lost_event.lost        = atomic_xchg(&data->lost, 0);
3021
3022                 perf_output_put(handle, lost_event);
3023         }
3024
3025         return 0;
3026
3027 fail:
3028         atomic_inc(&data->lost);
3029         perf_output_unlock(handle);
3030 out:
3031         rcu_read_unlock();
3032
3033         return -ENOSPC;
3034 }
3035
3036 void perf_output_end(struct perf_output_handle *handle)
3037 {
3038         struct perf_event *event = handle->event;
3039         struct perf_mmap_data *data = handle->data;
3040
3041         int wakeup_events = event->attr.wakeup_events;
3042
3043         if (handle->sample && wakeup_events) {
3044                 int events = atomic_inc_return(&data->events);
3045                 if (events >= wakeup_events) {
3046                         atomic_sub(wakeup_events, &data->events);
3047                         atomic_set(&data->wakeup, 1);
3048                 }
3049         }
3050
3051         perf_output_unlock(handle);
3052         rcu_read_unlock();
3053 }
3054
3055 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
3056 {
3057         /*
3058          * only top level events have the pid namespace they were created in
3059          */
3060         if (event->parent)
3061                 event = event->parent;
3062
3063         return task_tgid_nr_ns(p, event->ns);
3064 }
3065
3066 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
3067 {
3068         /*
3069          * only top level events have the pid namespace they were created in
3070          */
3071         if (event->parent)
3072                 event = event->parent;
3073
3074         return task_pid_nr_ns(p, event->ns);
3075 }
3076
3077 static void perf_output_read_one(struct perf_output_handle *handle,
3078                                  struct perf_event *event)
3079 {
3080         u64 read_format = event->attr.read_format;
3081         u64 values[4];
3082         int n = 0;
3083
3084         values[n++] = atomic64_read(&event->count);
3085         if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3086                 values[n++] = event->total_time_enabled +
3087                         atomic64_read(&event->child_total_time_enabled);
3088         }
3089         if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3090                 values[n++] = event->total_time_running +
3091                         atomic64_read(&event->child_total_time_running);
3092         }
3093         if (read_format & PERF_FORMAT_ID)
3094                 values[n++] = primary_event_id(event);
3095
3096         perf_output_copy(handle, values, n * sizeof(u64));
3097 }
3098
3099 /*
3100  * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
3101  */
3102 static void perf_output_read_group(struct perf_output_handle *handle,
3103                             struct perf_event *event)
3104 {
3105         struct perf_event *leader = event->group_leader, *sub;
3106         u64 read_format = event->attr.read_format;
3107         u64 values[5];
3108         int n = 0;
3109
3110         values[n++] = 1 + leader->nr_siblings;
3111
3112         if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3113                 values[n++] = leader->total_time_enabled;
3114
3115         if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3116                 values[n++] = leader->total_time_running;
3117
3118         if (leader != event)
3119                 leader->pmu->read(leader);
3120
3121         values[n++] = atomic64_read(&leader->count);
3122         if (read_format & PERF_FORMAT_ID)
3123                 values[n++] = primary_event_id(leader);
3124
3125         perf_output_copy(handle, values, n * sizeof(u64));
3126
3127         list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3128                 n = 0;
3129
3130                 if (sub != event)
3131                         sub->pmu->read(sub);
3132
3133                 values[n++] = atomic64_read(&sub->count);
3134                 if (read_format & PERF_FORMAT_ID)
3135                         values[n++] = primary_event_id(sub);
3136
3137                 perf_output_copy(handle, values, n * sizeof(u64));
3138         }
3139 }
3140
3141 static void perf_output_read(struct perf_output_handle *handle,
3142                              struct perf_event *event)
3143 {
3144         if (event->attr.read_format & PERF_FORMAT_GROUP)
3145                 perf_output_read_group(handle, event);
3146         else
3147                 perf_output_read_one(handle, event);
3148 }
3149
3150 void perf_output_sample(struct perf_output_handle *handle,
3151                         struct perf_event_header *header,
3152                         struct perf_sample_data *data,
3153                         struct perf_event *event)
3154 {
3155         u64 sample_type = data->type;
3156
3157         perf_output_put(handle, *header);
3158
3159         if (sample_type & PERF_SAMPLE_IP)
3160                 perf_output_put(handle, data->ip);
3161
3162         if (sample_type & PERF_SAMPLE_TID)
3163                 perf_output_put(handle, data->tid_entry);
3164
3165         if (sample_type & PERF_SAMPLE_TIME)
3166                 perf_output_put(handle, data->time);
3167
3168         if (sample_type & PERF_SAMPLE_ADDR)
3169                 perf_output_put(handle, data->addr);
3170
3171         if (sample_type & PERF_SAMPLE_ID)
3172                 perf_output_put(handle, data->id);
3173
3174         if (sample_type & PERF_SAMPLE_STREAM_ID)
3175                 perf_output_put(handle, data->stream_id);
3176
3177         if (sample_type & PERF_SAMPLE_CPU)
3178                 perf_output_put(handle, data->cpu_entry);
3179
3180         if (sample_type & PERF_SAMPLE_PERIOD)
3181                 perf_output_put(handle, data->period);
3182
3183         if (sample_type & PERF_SAMPLE_READ)
3184                 perf_output_read(handle, event);
3185
3186         if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3187                 if (data->callchain) {
3188                         int size = 1;
3189
3190                         if (data->callchain)
3191                                 size += data->callchain->nr;
3192
3193                         size *= sizeof(u64);
3194
3195                         perf_output_copy(handle, data->callchain, size);
3196                 } else {
3197                         u64 nr = 0;
3198                         perf_output_put(handle, nr);
3199                 }
3200         }
3201
3202         if (sample_type & PERF_SAMPLE_RAW) {
3203                 if (data->raw) {
3204                         perf_output_put(handle, data->raw->size);
3205                         perf_output_copy(handle, data->raw->data,
3206                                          data->raw->size);
3207                 } else {
3208                         struct {
3209                                 u32     size;
3210                                 u32     data;
3211                         } raw = {
3212                                 .size = sizeof(u32),
3213                                 .data = 0,
3214                         };
3215                         perf_output_put(handle, raw);
3216                 }
3217         }
3218 }
3219
3220 void perf_prepare_sample(struct perf_event_header *header,
3221                          struct perf_sample_data *data,
3222                          struct perf_event *event,
3223                          struct pt_regs *regs)
3224 {
3225         u64 sample_type = event->attr.sample_type;
3226
3227         data->type = sample_type;
3228
3229         header->type = PERF_RECORD_SAMPLE;
3230         header->size = sizeof(*header);
3231
3232         header->misc = 0;
3233         header->misc |= perf_misc_flags(regs);
3234
3235         if (sample_type & PERF_SAMPLE_IP) {
3236                 data->ip = perf_instruction_pointer(regs);
3237
3238                 header->size += sizeof(data->ip);
3239         }
3240
3241         if (sample_type & PERF_SAMPLE_TID) {
3242                 /* namespace issues */
3243                 data->tid_entry.pid = perf_event_pid(event, current);
3244                 data->tid_entry.tid = perf_event_tid(event, current);
3245
3246                 header->size += sizeof(data->tid_entry);
3247         }
3248
3249         if (sample_type & PERF_SAMPLE_TIME) {
3250                 data->time = perf_clock();
3251
3252                 header->size += sizeof(data->time);
3253         }
3254
3255         if (sample_type & PERF_SAMPLE_ADDR)
3256                 header->size += sizeof(data->addr);
3257
3258         if (sample_type & PERF_SAMPLE_ID) {
3259                 data->id = primary_event_id(event);
3260
3261                 header->size += sizeof(data->id);
3262         }
3263
3264         if (sample_type & PERF_SAMPLE_STREAM_ID) {
3265                 data->stream_id = event->id;
3266
3267                 header->size += sizeof(data->stream_id);
3268         }
3269
3270         if (sample_type & PERF_SAMPLE_CPU) {
3271                 data->cpu_entry.cpu             = raw_smp_processor_id();
3272                 data->cpu_entry.reserved        = 0;
3273
3274                 header->size += sizeof(data->cpu_entry);
3275         }
3276
3277         if (sample_type & PERF_SAMPLE_PERIOD)
3278                 header->size += sizeof(data->period);
3279
3280         if (sample_type & PERF_SAMPLE_READ)
3281                 header->size += perf_event_read_size(event);
3282
3283         if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3284                 int size = 1;
3285
3286                 data->callchain = perf_callchain(regs);
3287
3288                 if (data->callchain)
3289                         size += data->callchain->nr;
3290
3291                 header->size += size * sizeof(u64);
3292         }
3293
3294         if (sample_type & PERF_SAMPLE_RAW) {
3295                 int size = sizeof(u32);
3296
3297                 if (data->raw)
3298                         size += data->raw->size;
3299                 else
3300                         size += sizeof(u32);
3301
3302                 WARN_ON_ONCE(size & (sizeof(u64)-1));
3303                 header->size += size;
3304         }
3305 }
3306
3307 static void perf_event_output(struct perf_event *event, int nmi,
3308                                 struct perf_sample_data *data,
3309                                 struct pt_regs *regs)
3310 {
3311         struct perf_output_handle handle;
3312         struct perf_event_header header;
3313
3314         perf_prepare_sample(&header, data, event, regs);
3315
3316         if (perf_output_begin(&handle, event, header.size, nmi, 1))
3317                 return;
3318
3319         perf_output_sample(&handle, &header, data, event);
3320
3321         perf_output_end(&handle);
3322 }
3323
3324 /*
3325  * read event_id
3326  */
3327
3328 struct perf_read_event {
3329         struct perf_event_header        header;
3330
3331         u32                             pid;
3332         u32                             tid;
3333 };
3334
3335 static void
3336 perf_event_read_event(struct perf_event *event,
3337                         struct task_struct *task)
3338 {
3339         struct perf_output_handle handle;
3340         struct perf_read_event read_event = {
3341                 .header = {
3342                         .type = PERF_RECORD_READ,
3343                         .misc = 0,
3344                         .size = sizeof(read_event) + perf_event_read_size(event),
3345                 },
3346                 .pid = perf_event_pid(event, task),
3347                 .tid = perf_event_tid(event, task),
3348         };
3349         int ret;
3350
3351         ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0);
3352         if (ret)
3353                 return;
3354
3355         perf_output_put(&handle, read_event);
3356         perf_output_read(&handle, event);
3357
3358         perf_output_end(&handle);
3359 }
3360
3361 /*
3362  * task tracking -- fork/exit
3363  *
3364  * enabled by: attr.comm | attr.mmap | attr.task
3365  */
3366
3367 struct perf_task_event {
3368         struct task_struct              *task;
3369         struct perf_event_context       *task_ctx;
3370
3371         struct {
3372                 struct perf_event_header        header;
3373
3374                 u32                             pid;
3375                 u32                             ppid;
3376                 u32                             tid;
3377                 u32                             ptid;
3378                 u64                             time;
3379         } event_id;
3380 };
3381
3382 static void perf_event_task_output(struct perf_event *event,
3383                                      struct perf_task_event *task_event)
3384 {
3385         struct perf_output_handle handle;
3386         int size;
3387         struct task_struct *task = task_event->task;
3388         int ret;
3389
3390         size  = task_event->event_id.header.size;
3391         ret = perf_output_begin(&handle, event, size, 0, 0);
3392
3393         if (ret)
3394                 return;
3395
3396         task_event->event_id.pid = perf_event_pid(event, task);
3397         task_event->event_id.ppid = perf_event_pid(event, current);
3398
3399         task_event->event_id.tid = perf_event_tid(event, task);
3400         task_event->event_id.ptid = perf_event_tid(event, current);
3401
3402         task_event->event_id.time = perf_clock();
3403
3404         perf_output_put(&handle, task_event->event_id);
3405
3406         perf_output_end(&handle);
3407 }
3408
3409 static int perf_event_task_match(struct perf_event *event)
3410 {
3411         if (event->cpu != -1 && event->cpu != smp_processor_id())
3412                 return 0;
3413
3414         if (event->attr.comm || event->attr.mmap || event->attr.task)
3415                 return 1;
3416
3417         return 0;
3418 }
3419
3420 static void perf_event_task_ctx(struct perf_event_context *ctx,
3421                                   struct perf_task_event *task_event)
3422 {
3423         struct perf_event *event;
3424
3425         list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3426                 if (perf_event_task_match(event))
3427                         perf_event_task_output(event, task_event);
3428         }
3429 }
3430
3431 static void perf_event_task_event(struct perf_task_event *task_event)
3432 {
3433         struct perf_cpu_context *cpuctx;
3434         struct perf_event_context *ctx = task_event->task_ctx;
3435
3436         rcu_read_lock();
3437         cpuctx = &get_cpu_var(perf_cpu_context);
3438         perf_event_task_ctx(&cpuctx->ctx, task_event);
3439         if (!ctx)
3440                 ctx = rcu_dereference(task_event->task->perf_event_ctxp);
3441         if (ctx)
3442                 perf_event_task_ctx(ctx, task_event);
3443         put_cpu_var(perf_cpu_context);
3444         rcu_read_unlock();
3445 }
3446
3447 static void perf_event_task(struct task_struct *task,
3448                               struct perf_event_context *task_ctx,
3449                               int new)
3450 {
3451         struct perf_task_event task_event;
3452
3453         if (!atomic_read(&nr_comm_events) &&
3454             !atomic_read(&nr_mmap_events) &&
3455             !atomic_read(&nr_task_events))
3456                 return;
3457
3458         task_event = (struct perf_task_event){
3459                 .task     = task,
3460                 .task_ctx = task_ctx,
3461                 .event_id    = {
3462                         .header = {
3463                                 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
3464                                 .misc = 0,
3465                                 .size = sizeof(task_event.event_id),
3466                         },
3467                         /* .pid  */
3468                         /* .ppid */
3469                         /* .tid  */
3470                         /* .ptid */
3471                 },
3472         };
3473
3474         perf_event_task_event(&task_event);
3475 }
3476
3477 void perf_event_fork(struct task_struct *task)
3478 {
3479         perf_event_task(task, NULL, 1);
3480 }
3481
3482 /*
3483  * comm tracking
3484  */
3485
3486 struct perf_comm_event {
3487         struct task_struct      *task;
3488         char                    *comm;
3489         int                     comm_size;
3490
3491         struct {
3492                 struct perf_event_header        header;
3493
3494                 u32                             pid;
3495                 u32                             tid;
3496         } event_id;
3497 };
3498
3499 static void perf_event_comm_output(struct perf_event *event,
3500                                      struct perf_comm_event *comm_event)
3501 {
3502         struct perf_output_handle handle;
3503         int size = comm_event->event_id.header.size;
3504         int ret = perf_output_begin(&handle, event, size, 0, 0);
3505
3506         if (ret)
3507                 return;
3508
3509         comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
3510         comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
3511
3512         perf_output_put(&handle, comm_event->event_id);
3513         perf_output_copy(&handle, comm_event->comm,
3514                                    comm_event->comm_size);
3515         perf_output_end(&handle);
3516 }
3517
3518 static int perf_event_comm_match(struct perf_event *event)
3519 {
3520         if (event->cpu != -1 && event->cpu != smp_processor_id())
3521                 return 0;
3522
3523         if (event->attr.comm)
3524                 return 1;
3525
3526         return 0;
3527 }
3528
3529 static void perf_event_comm_ctx(struct perf_event_context *ctx,
3530                                   struct perf_comm_event *comm_event)
3531 {
3532         struct perf_event *event;
3533
3534         list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3535                 if (perf_event_comm_match(event))
3536                         perf_event_comm_output(event, comm_event);
3537         }
3538 }
3539
3540 static void perf_event_comm_event(struct perf_comm_event *comm_event)
3541 {
3542         struct perf_cpu_context *cpuctx;
3543         struct perf_event_context *ctx;
3544         unsigned int size;
3545         char comm[TASK_COMM_LEN];
3546
3547         memset(comm, 0, sizeof(comm));
3548         strlcpy(comm, comm_event->task->comm, sizeof(comm));
3549         size = ALIGN(strlen(comm)+1, sizeof(u64));
3550
3551         comm_event->comm = comm;
3552         comm_event->comm_size = size;
3553
3554         comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
3555
3556         rcu_read_lock();
3557         cpuctx = &get_cpu_var(perf_cpu_context);
3558         perf_event_comm_ctx(&cpuctx->ctx, comm_event);
3559         ctx = rcu_dereference(current->perf_event_ctxp);
3560         if (ctx)
3561                 perf_event_comm_ctx(ctx, comm_event);
3562         put_cpu_var(perf_cpu_context);
3563         rcu_read_unlock();
3564 }
3565
3566 void perf_event_comm(struct task_struct *task)
3567 {
3568         struct perf_comm_event comm_event;
3569
3570         if (task->perf_event_ctxp)
3571                 perf_event_enable_on_exec(task);
3572
3573         if (!atomic_read(&nr_comm_events))
3574                 return;
3575
3576         comm_event = (struct perf_comm_event){
3577                 .task   = task,
3578                 /* .comm      */
3579                 /* .comm_size */
3580                 .event_id  = {
3581                         .header = {
3582                                 .type = PERF_RECORD_COMM,
3583                                 .misc = 0,
3584                                 /* .size */
3585                         },
3586                         /* .pid */
3587                         /* .tid */
3588                 },
3589         };
3590
3591         perf_event_comm_event(&comm_event);
3592 }
3593
3594 /*
3595  * mmap tracking
3596  */
3597
3598 struct perf_mmap_event {
3599         struct vm_area_struct   *vma;
3600
3601         const char              *file_name;
3602         int                     file_size;
3603
3604         struct {
3605                 struct perf_event_header        header;
3606
3607                 u32                             pid;
3608                 u32                             tid;
3609                 u64                             start;
3610                 u64                             len;
3611                 u64                             pgoff;
3612         } event_id;
3613 };
3614
3615 static void perf_event_mmap_output(struct perf_event *event,
3616                                      struct perf_mmap_event *mmap_event)
3617 {
3618         struct perf_output_handle handle;
3619         int size = mmap_event->event_id.header.size;
3620         int ret = perf_output_begin(&handle, event, size, 0, 0);
3621
3622         if (ret)
3623                 return;
3624
3625         mmap_event->event_id.pid = perf_event_pid(event, current);
3626         mmap_event->event_id.tid = perf_event_tid(event, current);
3627
3628         perf_output_put(&handle, mmap_event->event_id);
3629         perf_output_copy(&handle, mmap_event->file_name,
3630                                    mmap_event->file_size);
3631         perf_output_end(&handle);
3632 }
3633
3634 static int perf_event_mmap_match(struct perf_event *event,
3635                                    struct perf_mmap_event *mmap_event)
3636 {
3637         if (event->cpu != -1 && event->cpu != smp_processor_id())
3638                 return 0;
3639
3640         if (event->attr.mmap)
3641                 return 1;
3642
3643         return 0;
3644 }
3645
3646 static void perf_event_mmap_ctx(struct perf_event_context *ctx,
3647                                   struct perf_mmap_event *mmap_event)
3648 {
3649         struct perf_event *event;
3650
3651         list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3652                 if (perf_event_mmap_match(event, mmap_event))
3653                         perf_event_mmap_output(event, mmap_event);
3654         }
3655 }
3656
3657 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
3658 {
3659         struct perf_cpu_context *cpuctx;
3660         struct perf_event_context *ctx;
3661         struct vm_area_struct *vma = mmap_event->vma;
3662         struct file *file = vma->vm_file;
3663         unsigned int size;
3664         char tmp[16];
3665         char *buf = NULL;
3666         const char *name;
3667
3668         memset(tmp, 0, sizeof(tmp));
3669
3670         if (file) {
3671                 /*
3672                  * d_path works from the end of the buffer backwards, so we
3673                  * need to add enough zero bytes after the string to handle
3674                  * the 64bit alignment we do later.
3675                  */
3676                 buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
3677                 if (!buf) {
3678                         name = strncpy(tmp, "//enomem", sizeof(tmp));
3679                         goto got_name;
3680                 }
3681                 name = d_path(&file->f_path, buf, PATH_MAX);
3682                 if (IS_ERR(name)) {
3683                         name = strncpy(tmp, "//toolong", sizeof(tmp));
3684                         goto got_name;
3685                 }
3686         } else {
3687                 if (arch_vma_name(mmap_event->vma)) {
3688                         name = strncpy(tmp, arch_vma_name(mmap_event->vma),
3689                                        sizeof(tmp));
3690                         goto got_name;
3691                 }
3692
3693                 if (!vma->vm_mm) {
3694                         name = strncpy(tmp, "[vdso]", sizeof(tmp));
3695                         goto got_name;
3696                 }
3697
3698                 name = strncpy(tmp, "//anon", sizeof(tmp));
3699                 goto got_name;
3700         }
3701
3702 got_name:
3703         size = ALIGN(strlen(name)+1, sizeof(u64));
3704
3705         mmap_event->file_name = name;
3706         mmap_event->file_size = size;
3707
3708         mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
3709
3710         rcu_read_lock();
3711         cpuctx = &get_cpu_var(perf_cpu_context);
3712         perf_event_mmap_ctx(&cpuctx->ctx, mmap_event);
3713         ctx = rcu_dereference(current->perf_event_ctxp);
3714         if (ctx)
3715                 perf_event_mmap_ctx(ctx, mmap_event);
3716         put_cpu_var(perf_cpu_context);
3717         rcu_read_unlock();
3718
3719         kfree(buf);
3720 }
3721
3722 void __perf_event_mmap(struct vm_area_struct *vma)
3723 {
3724         struct perf_mmap_event mmap_event;
3725
3726         if (!atomic_read(&nr_mmap_events))
3727                 return;
3728
3729         mmap_event = (struct perf_mmap_event){
3730                 .vma    = vma,
3731                 /* .file_name */
3732                 /* .file_size */
3733                 .event_id  = {
3734                         .header = {
3735                                 .type = PERF_RECORD_MMAP,
3736                                 .misc = 0,
3737                                 /* .size */
3738                         },
3739                         /* .pid */
3740                         /* .tid */
3741                         .start  = vma->vm_start,
3742                         .len    = vma->vm_end - vma->vm_start,
3743                         .pgoff  = vma->vm_pgoff,
3744                 },
3745         };
3746
3747         perf_event_mmap_event(&mmap_event);
3748 }
3749
3750 /*
3751  * IRQ throttle logging
3752  */
3753
3754 static void perf_log_throttle(struct perf_event *event, int enable)
3755 {
3756         struct perf_output_handle handle;
3757         int ret;
3758
3759         struct {
3760                 struct perf_event_header        header;
3761                 u64                             time;
3762                 u64                             id;
3763                 u64                             stream_id;
3764         } throttle_event = {
3765                 .header = {
3766                         .type = PERF_RECORD_THROTTLE,
3767                         .misc = 0,
3768                         .size = sizeof(throttle_event),
3769                 },
3770                 .time           = perf_clock(),
3771                 .id             = primary_event_id(event),
3772                 .stream_id      = event->id,
3773         };
3774
3775         if (enable)
3776                 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
3777
3778         ret = perf_output_begin(&handle, event, sizeof(throttle_event), 1, 0);
3779         if (ret)
3780                 return;
3781
3782         perf_output_put(&handle, throttle_event);
3783         perf_output_end(&handle);
3784 }
3785
3786 /*
3787  * Generic event overflow handling, sampling.
3788  */
3789
3790 static int __perf_event_overflow(struct perf_event *event, int nmi,
3791                                    int throttle, struct perf_sample_data *data,
3792                                    struct pt_regs *regs)
3793 {
3794         int events = atomic_read(&event->event_limit);
3795         struct hw_perf_event *hwc = &event->hw;
3796         int ret = 0;
3797
3798         throttle = (throttle && event->pmu->unthrottle != NULL);
3799
3800         if (!throttle) {
3801                 hwc->interrupts++;
3802         } else {
3803                 if (hwc->interrupts != MAX_INTERRUPTS) {
3804                         hwc->interrupts++;
3805                         if (HZ * hwc->interrupts >
3806                                         (u64)sysctl_perf_event_sample_rate) {
3807                                 hwc->interrupts = MAX_INTERRUPTS;
3808                                 perf_log_throttle(event, 0);
3809                                 ret = 1;
3810                         }
3811                 } else {
3812                         /*
3813                          * Keep re-disabling events even though on the previous
3814                          * pass we disabled it - just in case we raced with a
3815                          * sched-in and the event got enabled again:
3816                          */
3817                         ret = 1;
3818                 }
3819         }
3820
3821         if (event->attr.freq) {
3822                 u64 now = perf_clock();
3823                 s64 delta = now - hwc->freq_time_stamp;
3824
3825                 hwc->freq_time_stamp = now;
3826
3827                 if (delta > 0 && delta < 2*TICK_NSEC)
3828                         perf_adjust_period(event, delta, hwc->last_period);
3829         }
3830
3831         /*
3832          * XXX event_limit might not quite work as expected on inherited
3833          * events
3834          */
3835
3836         event->pending_kill = POLL_IN;
3837         if (events && atomic_dec_and_test(&event->event_limit)) {
3838                 ret = 1;
3839                 event->pending_kill = POLL_HUP;
3840                 if (nmi) {
3841                         event->pending_disable = 1;
3842                         perf_pending_queue(&event->pending,
3843                                            perf_pending_event);
3844                 } else
3845                         perf_event_disable(event);
3846         }
3847
3848         if (event->overflow_handler)
3849                 event->overflow_handler(event, nmi, data, regs);
3850         else
3851                 perf_event_output(event, nmi, data, regs);
3852
3853         return ret;
3854 }
3855
3856 int perf_event_overflow(struct perf_event *event, int nmi,
3857                           struct perf_sample_data *data,
3858                           struct pt_regs *regs)
3859 {
3860         return __perf_event_overflow(event, nmi, 1, data, regs);
3861 }
3862
3863 /*
3864  * Generic software event infrastructure
3865  */
3866
3867 /*
3868  * We directly increment event->count and keep a second value in
3869  * event->hw.period_left to count intervals. This period event
3870  * is kept in the range [-sample_period, 0] so that we can use the
3871  * sign as trigger.
3872  */
3873
3874 static u64 perf_swevent_set_period(struct perf_event *event)
3875 {
3876         struct hw_perf_event *hwc = &event->hw;
3877         u64 period = hwc->last_period;
3878         u64 nr, offset;
3879         s64 old, val;
3880
3881         hwc->last_period = hwc->sample_period;
3882
3883 again:
3884         old = val = atomic64_read(&hwc->period_left);
3885         if (val < 0)
3886                 return 0;
3887
3888         nr = div64_u64(period + val, period);
3889         offset = nr * period;
3890         val -= offset;
3891         if (atomic64_cmpxchg(&hwc->period_left, old, val) != old)
3892                 goto again;
3893
3894         return nr;
3895 }
3896
3897 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
3898                                     int nmi, struct perf_sample_data *data,
3899                                     struct pt_regs *regs)
3900 {
3901         struct hw_perf_event *hwc = &event->hw;
3902         int throttle = 0;
3903
3904         data->period = event->hw.last_period;
3905         if (!overflow)
3906                 overflow = perf_swevent_set_period(event);
3907
3908         if (hwc->interrupts == MAX_INTERRUPTS)
3909                 return;
3910
3911         for (; overflow; overflow--) {
3912                 if (__perf_event_overflow(event, nmi, throttle,
3913                                             data, regs)) {
3914                         /*
3915                          * We inhibit the overflow from happening when
3916                          * hwc->interrupts == MAX_INTERRUPTS.
3917                          */
3918                         break;
3919                 }
3920                 throttle = 1;
3921         }
3922 }
3923
3924 static void perf_swevent_unthrottle(struct perf_event *event)
3925 {
3926         /*
3927          * Nothing to do, we already reset hwc->interrupts.
3928          */
3929 }
3930
3931 static void perf_swevent_add(struct perf_event *event, u64 nr,
3932                                int nmi, struct perf_sample_data *data,
3933                                struct pt_regs *regs)
3934 {
3935         struct hw_perf_event *hwc = &event->hw;
3936
3937         atomic64_add(nr, &event->count);
3938
3939         if (!regs)
3940                 return;
3941
3942         if (!hwc->sample_period)
3943                 return;
3944
3945         if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
3946                 return perf_swevent_overflow(event, 1, nmi, data, regs);
3947
3948         if (atomic64_add_negative(nr, &hwc->period_left))
3949                 return;
3950
3951         perf_swevent_overflow(event, 0, nmi, data, regs);
3952 }
3953
3954 static int perf_swevent_is_counting(struct perf_event *event)
3955 {
3956         /*
3957          * The event is active, we're good!
3958          */
3959         if (event->state == PERF_EVENT_STATE_ACTIVE)
3960                 return 1;
3961
3962         /*
3963          * The event is off/error, not counting.
3964          */
3965         if (event->state != PERF_EVENT_STATE_INACTIVE)
3966                 return 0;
3967
3968         /*
3969          * The event is inactive, if the context is active
3970          * we're part of a group that didn't make it on the 'pmu',
3971          * not counting.
3972          */
3973         if (event->ctx->is_active)
3974                 return 0;
3975
3976         /*
3977          * We're inactive and the context is too, this means the
3978          * task is scheduled out, we're counting events that happen
3979          * to us, like migration events.
3980          */
3981         return 1;
3982 }
3983
3984 static int perf_tp_event_match(struct perf_event *event,
3985                                 struct perf_sample_data *data);
3986
3987 static int perf_exclude_event(struct perf_event *event,
3988                               struct pt_regs *regs)
3989 {
3990         if (regs) {
3991                 if (event->attr.exclude_user && user_mode(regs))
3992                         return 1;
3993
3994                 if (event->attr.exclude_kernel && !user_mode(regs))
3995                         return 1;
3996         }
3997
3998         return 0;
3999 }
4000
4001 static int perf_swevent_match(struct perf_event *event,
4002                                 enum perf_type_id type,
4003                                 u32 event_id,
4004                                 struct perf_sample_data *data,
4005                                 struct pt_regs *regs)
4006 {
4007         if (event->cpu != -1 && event->cpu != smp_processor_id())
4008                 return 0;
4009
4010         if (!perf_swevent_is_counting(event))
4011                 return 0;
4012
4013         if (event->attr.type != type)
4014                 return 0;
4015
4016         if (event->attr.config != event_id)
4017                 return 0;
4018
4019         if (perf_exclude_event(event, regs))
4020                 return 0;
4021
4022         if (event->attr.type == PERF_TYPE_TRACEPOINT &&
4023             !perf_tp_event_match(event, data))
4024                 return 0;
4025
4026         return 1;
4027 }
4028
4029 static void perf_swevent_ctx_event(struct perf_event_context *ctx,
4030                                      enum perf_type_id type,
4031                                      u32 event_id, u64 nr, int nmi,
4032                                      struct perf_sample_data *data,
4033                                      struct pt_regs *regs)
4034 {
4035         struct perf_event *event;
4036
4037         list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4038                 if (perf_swevent_match(event, type, event_id, data, regs))
4039                         perf_swevent_add(event, nr, nmi, data, regs);
4040         }
4041 }
4042
4043 int perf_swevent_get_recursion_context(void)
4044 {
4045         struct perf_cpu_context *cpuctx = &get_cpu_var(perf_cpu_context);
4046         int rctx;
4047
4048         if (in_nmi())
4049                 rctx = 3;
4050         else if (in_irq())
4051                 rctx = 2;
4052         else if (in_softirq())
4053                 rctx = 1;
4054         else
4055                 rctx = 0;
4056
4057         if (cpuctx->recursion[rctx]) {
4058                 put_cpu_var(perf_cpu_context);
4059                 return -1;
4060         }
4061
4062         cpuctx->recursion[rctx]++;
4063         barrier();
4064
4065         return rctx;
4066 }
4067 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
4068
4069 void perf_swevent_put_recursion_context(int rctx)
4070 {
4071         struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
4072         barrier();
4073         cpuctx->recursion[rctx]--;
4074         put_cpu_var(perf_cpu_context);
4075 }
4076 EXPORT_SYMBOL_GPL(perf_swevent_put_recursion_context);
4077
4078 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
4079                                     u64 nr, int nmi,
4080                                     struct perf_sample_data *data,
4081                                     struct pt_regs *regs)
4082 {
4083         struct perf_cpu_context *cpuctx;
4084         struct perf_event_context *ctx;
4085
4086         cpuctx = &__get_cpu_var(perf_cpu_context);
4087         rcu_read_lock();
4088         perf_swevent_ctx_event(&cpuctx->ctx, type, event_id,
4089                                  nr, nmi, data, regs);
4090         /*
4091          * doesn't really matter which of the child contexts the
4092          * events ends up in.
4093          */
4094         ctx = rcu_dereference(current->perf_event_ctxp);
4095         if (ctx)
4096                 perf_swevent_ctx_event(ctx, type, event_id, nr, nmi, data, regs);
4097         rcu_read_unlock();
4098 }
4099
4100 void __perf_sw_event(u32 event_id, u64 nr, int nmi,
4101                             struct pt_regs *regs, u64 addr)
4102 {
4103         struct perf_sample_data data;
4104         int rctx;
4105
4106         rctx = perf_swevent_get_recursion_context();
4107         if (rctx < 0)
4108                 return;
4109
4110         data.addr = addr;
4111         data.raw  = NULL;
4112
4113         do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs);
4114
4115         perf_swevent_put_recursion_context(rctx);
4116 }
4117
4118 static void perf_swevent_read(struct perf_event *event)
4119 {
4120 }
4121
4122 static int perf_swevent_enable(struct perf_event *event)
4123 {
4124         struct hw_perf_event *hwc = &event->hw;
4125
4126         if (hwc->sample_period) {
4127                 hwc->last_period = hwc->sample_period;
4128                 perf_swevent_set_period(event);
4129         }
4130         return 0;
4131 }
4132
4133 static void perf_swevent_disable(struct perf_event *event)
4134 {
4135 }
4136
4137 static const struct pmu perf_ops_generic = {
4138         .enable         = perf_swevent_enable,
4139         .disable        = perf_swevent_disable,
4140         .read           = perf_swevent_read,
4141         .unthrottle     = perf_swevent_unthrottle,
4142 };
4143
4144 /*
4145  * hrtimer based swevent callback
4146  */
4147
4148 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
4149 {
4150         enum hrtimer_restart ret = HRTIMER_RESTART;
4151         struct perf_sample_data data;
4152         struct pt_regs *regs;
4153         struct perf_event *event;
4154         u64 period;
4155
4156         event   = container_of(hrtimer, struct perf_event, hw.hrtimer);
4157         event->pmu->read(event);
4158
4159         data.addr = 0;
4160         data.raw = NULL;
4161         data.period = event->hw.last_period;
4162         regs = get_irq_regs();
4163         /*
4164          * In case we exclude kernel IPs or are somehow not in interrupt
4165          * context, provide the next best thing, the user IP.
4166          */
4167         if ((event->attr.exclude_kernel || !regs) &&
4168                         !event->attr.exclude_user)
4169                 regs = task_pt_regs(current);
4170
4171         if (regs) {
4172                 if (!(event->attr.exclude_idle && current->pid == 0))
4173                         if (perf_event_overflow(event, 0, &data, regs))
4174                                 ret = HRTIMER_NORESTART;
4175         }
4176
4177         period = max_t(u64, 10000, event->hw.sample_period);
4178         hrtimer_forward_now(hrtimer, ns_to_ktime(period));
4179
4180         return ret;
4181 }
4182
4183 static void perf_swevent_start_hrtimer(struct perf_event *event)
4184 {
4185         struct hw_perf_event *hwc = &event->hw;
4186
4187         hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
4188         hwc->hrtimer.function = perf_swevent_hrtimer;
4189         if (hwc->sample_period) {
4190                 u64 period;
4191
4192                 if (hwc->remaining) {
4193                         if (hwc->remaining < 0)
4194                                 period = 10000;
4195                         else
4196                                 period = hwc->remaining;
4197                         hwc->remaining = 0;
4198                 } else {
4199                         period = max_t(u64, 10000, hwc->sample_period);
4200                 }
4201                 __hrtimer_start_range_ns(&hwc->hrtimer,
4202                                 ns_to_ktime(period), 0,
4203                                 HRTIMER_MODE_REL, 0);
4204         }
4205 }
4206
4207 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
4208 {
4209         struct hw_perf_event *hwc = &event->hw;
4210
4211         if (hwc->sample_period) {
4212                 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
4213                 hwc->remaining = ktime_to_ns(remaining);
4214
4215                 hrtimer_cancel(&hwc->hrtimer);
4216         }
4217 }
4218
4219 /*
4220  * Software event: cpu wall time clock
4221  */
4222
4223 static void cpu_clock_perf_event_update(struct perf_event *event)
4224 {
4225         int cpu = raw_smp_processor_id();
4226         s64 prev;
4227         u64 now;
4228
4229         now = cpu_clock(cpu);
4230         prev = atomic64_xchg(&event->hw.prev_count, now);
4231         atomic64_add(now - prev, &event->count);
4232 }
4233
4234 static int cpu_clock_perf_event_enable(struct perf_event *event)
4235 {
4236         struct hw_perf_event *hwc = &event->hw;
4237         int cpu = raw_smp_processor_id();
4238
4239         atomic64_set(&hwc->prev_count, cpu_clock(cpu));
4240         perf_swevent_start_hrtimer(event);
4241
4242         return 0;
4243 }
4244
4245 static void cpu_clock_perf_event_disable(struct perf_event *event)
4246 {
4247         perf_swevent_cancel_hrtimer(event);
4248         cpu_clock_perf_event_update(event);
4249 }
4250
4251 static void cpu_clock_perf_event_read(struct perf_event *event)
4252 {
4253         cpu_clock_perf_event_update(event);
4254 }
4255
4256 static const struct pmu perf_ops_cpu_clock = {
4257         .enable         = cpu_clock_perf_event_enable,
4258         .disable        = cpu_clock_perf_event_disable,
4259         .read           = cpu_clock_perf_event_read,
4260 };
4261
4262 /*
4263  * Software event: task time clock
4264  */
4265
4266 static void task_clock_perf_event_update(struct perf_event *event, u64 now)
4267 {
4268         u64 prev;
4269         s64 delta;
4270
4271         prev = atomic64_xchg(&event->hw.prev_count, now);
4272         delta = now - prev;
4273         atomic64_add(delta, &event->count);
4274 }
4275
4276 static int task_clock_perf_event_enable(struct perf_event *event)
4277 {
4278         struct hw_perf_event *hwc = &event->hw;
4279         u64 now;
4280
4281         now = event->ctx->time;
4282
4283         atomic64_set(&hwc->prev_count, now);
4284
4285         perf_swevent_start_hrtimer(event);
4286
4287         return 0;
4288 }
4289
4290 static void task_clock_perf_event_disable(struct perf_event *event)
4291 {
4292         perf_swevent_cancel_hrtimer(event);
4293         task_clock_perf_event_update(event, event->ctx->time);
4294
4295 }
4296
4297 static void task_clock_perf_event_read(struct perf_event *event)
4298 {
4299         u64 time;
4300
4301         if (!in_nmi()) {
4302                 update_context_time(event->ctx);
4303                 time = event->ctx->time;
4304         } else {
4305                 u64 now = perf_clock();
4306                 u64 delta = now - event->ctx->timestamp;
4307                 time = event->ctx->time + delta;
4308         }
4309
4310         task_clock_perf_event_update(event, time);
4311 }
4312
4313 static const struct pmu perf_ops_task_clock = {
4314         .enable         = task_clock_perf_event_enable,
4315         .disable        = task_clock_perf_event_disable,
4316         .read           = task_clock_perf_event_read,
4317 };
4318
4319 #ifdef CONFIG_EVENT_TRACING
4320
4321 void perf_tp_event(int event_id, u64 addr, u64 count, void *record,
4322                           int entry_size)
4323 {
4324         struct perf_raw_record raw = {
4325                 .size = entry_size,
4326                 .data = record,
4327         };
4328
4329         struct perf_sample_data data = {
4330                 .addr = addr,
4331                 .raw = &raw,
4332         };
4333
4334         struct pt_regs *regs = get_irq_regs();
4335
4336         if (!regs)
4337                 regs = task_pt_regs(current);
4338
4339         /* Trace events already protected against recursion */
4340         do_perf_sw_event(PERF_TYPE_TRACEPOINT, event_id, count, 1,
4341                                 &data, regs);
4342 }
4343 EXPORT_SYMBOL_GPL(perf_tp_event);
4344
4345 static int perf_tp_event_match(struct perf_event *event,
4346                                 struct perf_sample_data *data)
4347 {
4348         void *record = data->raw->data;
4349
4350         if (likely(!event->filter) || filter_match_preds(event->filter, record))
4351                 return 1;
4352         return 0;
4353 }
4354
4355 static void tp_perf_event_destroy(struct perf_event *event)
4356 {
4357         ftrace_profile_disable(event->attr.config);
4358 }
4359
4360 static const struct pmu *tp_perf_event_init(struct perf_event *event)
4361 {
4362         /*
4363          * Raw tracepoint data is a severe data leak, only allow root to
4364          * have these.
4365          */
4366         if ((event->attr.sample_type & PERF_SAMPLE_RAW) &&
4367                         perf_paranoid_tracepoint_raw() &&
4368                         !capable(CAP_SYS_ADMIN))
4369                 return ERR_PTR(-EPERM);
4370
4371         if (ftrace_profile_enable(event->attr.config))
4372                 return NULL;
4373
4374         event->destroy = tp_perf_event_destroy;
4375
4376         return &perf_ops_generic;
4377 }
4378
4379 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
4380 {
4381         char *filter_str;
4382         int ret;
4383
4384         if (event->attr.type != PERF_TYPE_TRACEPOINT)
4385                 return -EINVAL;
4386
4387         filter_str = strndup_user(arg, PAGE_SIZE);
4388         if (IS_ERR(filter_str))
4389                 return PTR_ERR(filter_str);
4390
4391         ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
4392
4393         kfree(filter_str);
4394         return ret;
4395 }
4396
4397 static void perf_event_free_filter(struct perf_event *event)
4398 {
4399         ftrace_profile_free_filter(event);
4400 }
4401
4402 #else
4403
4404 static int perf_tp_event_match(struct perf_event *event,
4405                                 struct perf_sample_data *data)
4406 {
4407         return 1;
4408 }
4409
4410 static const struct pmu *tp_perf_event_init(struct perf_event *event)
4411 {
4412         return NULL;
4413 }
4414
4415 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
4416 {
4417         return -ENOENT;
4418 }
4419
4420 static void perf_event_free_filter(struct perf_event *event)
4421 {
4422 }
4423
4424 #endif /* CONFIG_EVENT_TRACING */
4425
4426 #ifdef CONFIG_HAVE_HW_BREAKPOINT
4427 static void bp_perf_event_destroy(struct perf_event *event)
4428 {
4429         release_bp_slot(event);
4430 }
4431
4432 static const struct pmu *bp_perf_event_init(struct perf_event *bp)
4433 {
4434         int err;
4435
4436         err = register_perf_hw_breakpoint(bp);
4437         if (err)
4438                 return ERR_PTR(err);
4439
4440         bp->destroy = bp_perf_event_destroy;
4441
4442         return &perf_ops_bp;
4443 }
4444
4445 void perf_bp_event(struct perf_event *bp, void *data)
4446 {
4447         struct perf_sample_data sample;
4448         struct pt_regs *regs = data;
4449
4450         sample.raw = NULL;
4451         sample.addr = bp->attr.bp_addr;
4452
4453         if (!perf_exclude_event(bp, regs))
4454                 perf_swevent_add(bp, 1, 1, &sample, regs);
4455 }
4456 #else
4457 static const struct pmu *bp_perf_event_init(struct perf_event *bp)
4458 {
4459         return NULL;
4460 }
4461
4462 void perf_bp_event(struct perf_event *bp, void *regs)
4463 {
4464 }
4465 #endif
4466
4467 atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX];
4468
4469 static void sw_perf_event_destroy(struct perf_event *event)
4470 {
4471         u64 event_id = event->attr.config;
4472
4473         WARN_ON(event->parent);
4474
4475         atomic_dec(&perf_swevent_enabled[event_id]);
4476 }
4477
4478 static const struct pmu *sw_perf_event_init(struct perf_event *event)
4479 {
4480         const struct pmu *pmu = NULL;
4481         u64 event_id = event->attr.config;
4482
4483         /*
4484          * Software events (currently) can't in general distinguish
4485          * between user, kernel and hypervisor events.
4486          * However, context switches and cpu migrations are considered
4487          * to be kernel events, and page faults are never hypervisor
4488          * events.
4489          */
4490         switch (event_id) {
4491         case PERF_COUNT_SW_CPU_CLOCK:
4492                 pmu = &perf_ops_cpu_clock;
4493
4494                 break;
4495         case PERF_COUNT_SW_TASK_CLOCK:
4496                 /*
4497                  * If the user instantiates this as a per-cpu event,
4498                  * use the cpu_clock event instead.
4499                  */
4500                 if (event->ctx->task)
4501                         pmu = &perf_ops_task_clock;
4502                 else
4503                         pmu = &perf_ops_cpu_clock;
4504
4505                 break;
4506         case PERF_COUNT_SW_PAGE_FAULTS:
4507         case PERF_COUNT_SW_PAGE_FAULTS_MIN:
4508         case PERF_COUNT_SW_PAGE_FAULTS_MAJ:
4509         case PERF_COUNT_SW_CONTEXT_SWITCHES:
4510         case PERF_COUNT_SW_CPU_MIGRATIONS:
4511         case PERF_COUNT_SW_ALIGNMENT_FAULTS:
4512         case PERF_COUNT_SW_EMULATION_FAULTS:
4513                 if (!event->parent) {
4514                         atomic_inc(&perf_swevent_enabled[event_id]);
4515                         event->destroy = sw_perf_event_destroy;
4516                 }
4517                 pmu = &perf_ops_generic;
4518                 break;
4519         }
4520
4521         return pmu;
4522 }
4523
4524 /*
4525  * Allocate and initialize a event structure
4526  */
4527 static struct perf_event *
4528 perf_event_alloc(struct perf_event_attr *attr,
4529                    int cpu,
4530                    struct perf_event_context *ctx,
4531                    struct perf_event *group_leader,
4532                    struct perf_event *parent_event,
4533                    perf_overflow_handler_t overflow_handler,
4534                    gfp_t gfpflags)
4535 {
4536         const struct pmu *pmu;
4537         struct perf_event *event;
4538         struct hw_perf_event *hwc;
4539         long err;
4540
4541         event = kzalloc(sizeof(*event), gfpflags);
4542         if (!event)
4543                 return ERR_PTR(-ENOMEM);
4544
4545         /*
4546          * Single events are their own group leaders, with an
4547          * empty sibling list:
4548          */
4549         if (!group_leader)
4550                 group_leader = event;
4551
4552         mutex_init(&event->child_mutex);
4553         INIT_LIST_HEAD(&event->child_list);
4554
4555         INIT_LIST_HEAD(&event->group_entry);
4556         INIT_LIST_HEAD(&event->event_entry);
4557         INIT_LIST_HEAD(&event->sibling_list);
4558         init_waitqueue_head(&event->waitq);
4559
4560         mutex_init(&event->mmap_mutex);
4561
4562         event->cpu              = cpu;
4563         event->attr             = *attr;
4564         event->group_leader     = group_leader;
4565         event->pmu              = NULL;
4566         event->ctx              = ctx;
4567         event->oncpu            = -1;
4568
4569         event->parent           = parent_event;
4570
4571         event->ns               = get_pid_ns(current->nsproxy->pid_ns);
4572         event->id               = atomic64_inc_return(&perf_event_id);
4573
4574         event->state            = PERF_EVENT_STATE_INACTIVE;
4575
4576         if (!overflow_handler && parent_event)
4577                 overflow_handler = parent_event->overflow_handler;
4578         
4579         event->overflow_handler = overflow_handler;
4580
4581         if (attr->disabled)
4582                 event->state = PERF_EVENT_STATE_OFF;
4583
4584         pmu = NULL;
4585
4586         hwc = &event->hw;
4587         hwc->sample_period = attr->sample_period;
4588         if (attr->freq && attr->sample_freq)
4589                 hwc->sample_period = 1;
4590         hwc->last_period = hwc->sample_period;
4591
4592         atomic64_set(&hwc->period_left, hwc->sample_period);
4593
4594         /*
4595          * we currently do not support PERF_FORMAT_GROUP on inherited events
4596          */
4597         if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
4598                 goto done;
4599
4600         switch (attr->type) {
4601         case PERF_TYPE_RAW:
4602         case PERF_TYPE_HARDWARE:
4603         case PERF_TYPE_HW_CACHE:
4604                 pmu = hw_perf_event_init(event);
4605                 break;
4606
4607         case PERF_TYPE_SOFTWARE:
4608                 pmu = sw_perf_event_init(event);
4609                 break;
4610
4611         case PERF_TYPE_TRACEPOINT:
4612                 pmu = tp_perf_event_init(event);
4613                 break;
4614
4615         case PERF_TYPE_BREAKPOINT:
4616                 pmu = bp_perf_event_init(event);
4617                 break;
4618
4619
4620         default:
4621                 break;
4622         }
4623 done:
4624         err = 0;
4625         if (!pmu)
4626                 err = -EINVAL;
4627         else if (IS_ERR(pmu))
4628                 err = PTR_ERR(pmu);
4629
4630         if (err) {
4631                 if (event->ns)
4632                         put_pid_ns(event->ns);
4633                 kfree(event);
4634                 return ERR_PTR(err);
4635         }
4636
4637         event->pmu = pmu;
4638
4639         if (!event->parent) {
4640                 atomic_inc(&nr_events);
4641                 if (event->attr.mmap)
4642                         atomic_inc(&nr_mmap_events);
4643                 if (event->attr.comm)
4644                         atomic_inc(&nr_comm_events);
4645                 if (event->attr.task)
4646                         atomic_inc(&nr_task_events);
4647         }
4648
4649         return event;
4650 }
4651
4652 static int perf_copy_attr(struct perf_event_attr __user *uattr,
4653                           struct perf_event_attr *attr)
4654 {
4655         u32 size;
4656         int ret;
4657
4658         if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
4659                 return -EFAULT;
4660
4661         /*
4662          * zero the full structure, so that a short copy will be nice.
4663          */
4664         memset(attr, 0, sizeof(*attr));
4665
4666         ret = get_user(size, &uattr->size);
4667         if (ret)
4668                 return ret;
4669
4670         if (size > PAGE_SIZE)   /* silly large */
4671                 goto err_size;
4672
4673         if (!size)              /* abi compat */
4674                 size = PERF_ATTR_SIZE_VER0;
4675
4676         if (size < PERF_ATTR_SIZE_VER0)
4677                 goto err_size;
4678
4679         /*
4680          * If we're handed a bigger struct than we know of,
4681          * ensure all the unknown bits are 0 - i.e. new
4682          * user-space does not rely on any kernel feature
4683          * extensions we dont know about yet.
4684          */
4685         if (size > sizeof(*attr)) {
4686                 unsigned char __user *addr;
4687                 unsigned char __user *end;
4688                 unsigned char val;
4689
4690                 addr = (void __user *)uattr + sizeof(*attr);
4691                 end  = (void __user *)uattr + size;
4692
4693                 for (; addr < end; addr++) {
4694                         ret = get_user(val, addr);
4695                         if (ret)
4696                                 return ret;
4697                         if (val)
4698                                 goto err_size;
4699                 }
4700                 size = sizeof(*attr);
4701         }
4702
4703         ret = copy_from_user(attr, uattr, size);
4704         if (ret)
4705                 return -EFAULT;
4706
4707         /*
4708          * If the type exists, the corresponding creation will verify
4709          * the attr->config.
4710          */
4711         if (attr->type >= PERF_TYPE_MAX)
4712                 return -EINVAL;
4713
4714         if (attr->__reserved_1 || attr->__reserved_2)
4715                 return -EINVAL;
4716
4717         if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
4718                 return -EINVAL;
4719
4720         if (attr->read_format & ~(PERF_FORMAT_MAX-1))
4721                 return -EINVAL;
4722
4723 out:
4724         return ret;
4725
4726 err_size:
4727         put_user(sizeof(*attr), &uattr->size);
4728         ret = -E2BIG;
4729         goto out;
4730 }
4731
4732 static int perf_event_set_output(struct perf_event *event, int output_fd)
4733 {
4734         struct perf_event *output_event = NULL;
4735         struct file *output_file = NULL;
4736         struct perf_event *old_output;
4737         int fput_needed = 0;
4738         int ret = -EINVAL;
4739
4740         if (!output_fd)
4741                 goto set;
4742
4743         output_file = fget_light(output_fd, &fput_needed);
4744         if (!output_file)
4745                 return -EBADF;
4746
4747         if (output_file->f_op != &perf_fops)
4748                 goto out;
4749
4750         output_event = output_file->private_data;
4751
4752         /* Don't chain output fds */
4753         if (output_event->output)
4754                 goto out;
4755
4756         /* Don't set an output fd when we already have an output channel */
4757         if (event->data)
4758                 goto out;
4759
4760         atomic_long_inc(&output_file->f_count);
4761
4762 set:
4763         mutex_lock(&event->mmap_mutex);
4764         old_output = event->output;
4765         rcu_assign_pointer(event->output, output_event);
4766         mutex_unlock(&event->mmap_mutex);
4767
4768         if (old_output) {
4769                 /*
4770                  * we need to make sure no existing perf_output_*()
4771                  * is still referencing this event.
4772                  */
4773                 synchronize_rcu();
4774                 fput(old_output->filp);
4775         }
4776
4777         ret = 0;
4778 out:
4779         fput_light(output_file, fput_needed);
4780         return ret;
4781 }
4782
4783 /**
4784  * sys_perf_event_open - open a performance event, associate it to a task/cpu
4785  *
4786  * @attr_uptr:  event_id type attributes for monitoring/sampling
4787  * @pid:                target pid
4788  * @cpu:                target cpu
4789  * @group_fd:           group leader event fd
4790  */
4791 SYSCALL_DEFINE5(perf_event_open,
4792                 struct perf_event_attr __user *, attr_uptr,
4793                 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
4794 {
4795         struct perf_event *event, *group_leader;
4796         struct perf_event_attr attr;
4797         struct perf_event_context *ctx;
4798         struct file *event_file = NULL;
4799         struct file *group_file = NULL;
4800         int fput_needed = 0;
4801         int fput_needed2 = 0;
4802         int err;
4803
4804         /* for future expandability... */
4805         if (flags & ~(PERF_FLAG_FD_NO_GROUP | PERF_FLAG_FD_OUTPUT))
4806                 return -EINVAL;
4807
4808         err = perf_copy_attr(attr_uptr, &attr);
4809         if (err)
4810                 return err;
4811
4812         if (!attr.exclude_kernel) {
4813                 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
4814                         return -EACCES;
4815         }
4816
4817         if (attr.freq) {
4818                 if (attr.sample_freq > sysctl_perf_event_sample_rate)
4819                         return -EINVAL;
4820         }
4821
4822         /*
4823          * Get the target context (task or percpu):
4824          */
4825         ctx = find_get_context(pid, cpu);
4826         if (IS_ERR(ctx))
4827                 return PTR_ERR(ctx);
4828
4829         /*
4830          * Look up the group leader (we will attach this event to it):
4831          */
4832         group_leader = NULL;
4833         if (group_fd != -1 && !(flags & PERF_FLAG_FD_NO_GROUP)) {
4834                 err = -EINVAL;
4835                 group_file = fget_light(group_fd, &fput_needed);
4836                 if (!group_file)
4837                         goto err_put_context;
4838                 if (group_file->f_op != &perf_fops)
4839                         goto err_put_context;
4840
4841                 group_leader = group_file->private_data;
4842                 /*
4843                  * Do not allow a recursive hierarchy (this new sibling
4844                  * becoming part of another group-sibling):
4845                  */
4846                 if (group_leader->group_leader != group_leader)
4847                         goto err_put_context;
4848                 /*
4849                  * Do not allow to attach to a group in a different
4850                  * task or CPU context:
4851                  */
4852                 if (group_leader->ctx != ctx)
4853                         goto err_put_context;
4854                 /*
4855                  * Only a group leader can be exclusive or pinned
4856                  */
4857                 if (attr.exclusive || attr.pinned)
4858                         goto err_put_context;
4859         }
4860
4861         event = perf_event_alloc(&attr, cpu, ctx, group_leader,
4862                                      NULL, NULL, GFP_KERNEL);
4863         err = PTR_ERR(event);
4864         if (IS_ERR(event))
4865                 goto err_put_context;
4866
4867         err = anon_inode_getfd("[perf_event]", &perf_fops, event, O_RDWR);
4868         if (err < 0)
4869                 goto err_free_put_context;
4870
4871         event_file = fget_light(err, &fput_needed2);
4872         if (!event_file)
4873                 goto err_free_put_context;
4874
4875         if (flags & PERF_FLAG_FD_OUTPUT) {
4876                 err = perf_event_set_output(event, group_fd);
4877                 if (err)
4878                         goto err_fput_free_put_context;
4879         }
4880
4881         event->filp = event_file;
4882         WARN_ON_ONCE(ctx->parent_ctx);
4883         mutex_lock(&ctx->mutex);
4884         perf_install_in_context(ctx, event, cpu);
4885         ++ctx->generation;
4886         mutex_unlock(&ctx->mutex);
4887
4888         event->owner = current;
4889         get_task_struct(current);
4890         mutex_lock(&current->perf_event_mutex);
4891         list_add_tail(&event->owner_entry, &current->perf_event_list);
4892         mutex_unlock(&current->perf_event_mutex);
4893
4894 err_fput_free_put_context:
4895         fput_light(event_file, fput_needed2);
4896
4897 err_free_put_context:
4898         if (err < 0)
4899                 kfree(event);
4900
4901 err_put_context:
4902         if (err < 0)
4903                 put_ctx(ctx);
4904
4905         fput_light(group_file, fput_needed);
4906
4907         return err;
4908 }
4909
4910 /**
4911  * perf_event_create_kernel_counter
4912  *
4913  * @attr: attributes of the counter to create
4914  * @cpu: cpu in which the counter is bound
4915  * @pid: task to profile
4916  */
4917 struct perf_event *
4918 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
4919                                  pid_t pid,
4920                                  perf_overflow_handler_t overflow_handler)
4921 {
4922         struct perf_event *event;
4923         struct perf_event_context *ctx;
4924         int err;
4925
4926         /*
4927          * Get the target context (task or percpu):
4928          */
4929
4930         ctx = find_get_context(pid, cpu);
4931         if (IS_ERR(ctx)) {
4932                 err = PTR_ERR(ctx);
4933                 goto err_exit;
4934         }
4935
4936         event = perf_event_alloc(attr, cpu, ctx, NULL,
4937                                  NULL, overflow_handler, GFP_KERNEL);
4938         if (IS_ERR(event)) {
4939                 err = PTR_ERR(event);
4940                 goto err_put_context;
4941         }
4942
4943         event->filp = NULL;
4944         WARN_ON_ONCE(ctx->parent_ctx);
4945         mutex_lock(&ctx->mutex);
4946         perf_install_in_context(ctx, event, cpu);
4947         ++ctx->generation;
4948         mutex_unlock(&ctx->mutex);
4949
4950         event->owner = current;
4951         get_task_struct(current);
4952         mutex_lock(&current->perf_event_mutex);
4953         list_add_tail(&event->owner_entry, &current->perf_event_list);
4954         mutex_unlock(&current->perf_event_mutex);
4955
4956         return event;
4957
4958  err_put_context:
4959         put_ctx(ctx);
4960  err_exit:
4961         return ERR_PTR(err);
4962 }
4963 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
4964
4965 /*
4966  * inherit a event from parent task to child task:
4967  */
4968 static struct perf_event *
4969 inherit_event(struct perf_event *parent_event,
4970               struct task_struct *parent,
4971               struct perf_event_context *parent_ctx,
4972               struct task_struct *child,
4973               struct perf_event *group_leader,
4974               struct perf_event_context *child_ctx)
4975 {
4976         struct perf_event *child_event;
4977
4978         /*
4979          * Instead of creating recursive hierarchies of events,
4980          * we link inherited events back to the original parent,
4981          * which has a filp for sure, which we use as the reference
4982          * count:
4983          */
4984         if (parent_event->parent)
4985                 parent_event = parent_event->parent;
4986
4987         child_event = perf_event_alloc(&parent_event->attr,
4988                                            parent_event->cpu, child_ctx,
4989                                            group_leader, parent_event,
4990                                            NULL, GFP_KERNEL);
4991         if (IS_ERR(child_event))
4992                 return child_event;
4993         get_ctx(child_ctx);
4994
4995         /*
4996          * Make the child state follow the state of the parent event,
4997          * not its attr.disabled bit.  We hold the parent's mutex,
4998          * so we won't race with perf_event_{en, dis}able_family.
4999          */
5000         if (parent_event->state >= PERF_EVENT_STATE_INACTIVE)
5001                 child_event->state = PERF_EVENT_STATE_INACTIVE;
5002         else
5003                 child_event->state = PERF_EVENT_STATE_OFF;
5004
5005         if (parent_event->attr.freq)
5006                 child_event->hw.sample_period = parent_event->hw.sample_period;
5007
5008         child_event->overflow_handler = parent_event->overflow_handler;
5009
5010         /*
5011          * Link it up in the child's context:
5012          */
5013         add_event_to_ctx(child_event, child_ctx);
5014
5015         /*
5016          * Get a reference to the parent filp - we will fput it
5017          * when the child event exits. This is safe to do because
5018          * we are in the parent and we know that the filp still
5019          * exists and has a nonzero count:
5020          */
5021         atomic_long_inc(&parent_event->filp->f_count);
5022
5023         /*
5024          * Link this into the parent event's child list
5025          */
5026         WARN_ON_ONCE(parent_event->ctx->parent_ctx);
5027         mutex_lock(&parent_event->child_mutex);
5028         list_add_tail(&child_event->child_list, &parent_event->child_list);
5029         mutex_unlock(&parent_event->child_mutex);
5030
5031         return child_event;
5032 }
5033
5034 static int inherit_group(struct perf_event *parent_event,
5035               struct task_struct *parent,
5036               struct perf_event_context *parent_ctx,
5037               struct task_struct *child,
5038               struct perf_event_context *child_ctx)
5039 {
5040         struct perf_event *leader;
5041         struct perf_event *sub;
5042         struct perf_event *child_ctr;
5043
5044         leader = inherit_event(parent_event, parent, parent_ctx,
5045                                  child, NULL, child_ctx);
5046         if (IS_ERR(leader))
5047                 return PTR_ERR(leader);
5048         list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
5049                 child_ctr = inherit_event(sub, parent, parent_ctx,
5050                                             child, leader, child_ctx);
5051                 if (IS_ERR(child_ctr))
5052                         return PTR_ERR(child_ctr);
5053         }
5054         return 0;
5055 }
5056
5057 static void sync_child_event(struct perf_event *child_event,
5058                                struct task_struct *child)
5059 {
5060         struct perf_event *parent_event = child_event->parent;
5061         u64 child_val;
5062
5063         if (child_event->attr.inherit_stat)
5064                 perf_event_read_event(child_event, child);
5065
5066         child_val = atomic64_read(&child_event->count);
5067
5068         /*
5069          * Add back the child's count to the parent's count:
5070          */
5071         atomic64_add(child_val, &parent_event->count);
5072         atomic64_add(child_event->total_time_enabled,
5073                      &parent_event->child_total_time_enabled);
5074         atomic64_add(child_event->total_time_running,
5075                      &parent_event->child_total_time_running);
5076
5077         /*
5078          * Remove this event from the parent's list
5079          */
5080         WARN_ON_ONCE(parent_event->ctx->parent_ctx);
5081         mutex_lock(&parent_event->child_mutex);
5082         list_del_init(&child_event->child_list);
5083         mutex_unlock(&parent_event->child_mutex);
5084
5085         /*
5086          * Release the parent event, if this was the last
5087          * reference to it.
5088          */
5089         fput(parent_event->filp);
5090 }
5091
5092 static void
5093 __perf_event_exit_task(struct perf_event *child_event,
5094                          struct perf_event_context *child_ctx,
5095                          struct task_struct *child)
5096 {
5097         struct perf_event *parent_event;
5098
5099         perf_event_remove_from_context(child_event);
5100
5101         parent_event = child_event->parent;
5102         /*
5103          * It can happen that parent exits first, and has events
5104          * that are still around due to the child reference. These
5105          * events need to be zapped - but otherwise linger.
5106          */
5107         if (parent_event) {
5108                 sync_child_event(child_event, child);
5109                 free_event(child_event);
5110         }
5111 }
5112
5113 /*
5114  * When a child task exits, feed back event values to parent events.
5115  */
5116 void perf_event_exit_task(struct task_struct *child)
5117 {
5118         struct perf_event *child_event, *tmp;
5119         struct perf_event_context *child_ctx;
5120         unsigned long flags;
5121
5122         if (likely(!child->perf_event_ctxp)) {
5123                 perf_event_task(child, NULL, 0);
5124                 return;
5125         }
5126
5127         local_irq_save(flags);
5128         /*
5129          * We can't reschedule here because interrupts are disabled,
5130          * and either child is current or it is a task that can't be
5131          * scheduled, so we are now safe from rescheduling changing
5132          * our context.
5133          */
5134         child_ctx = child->perf_event_ctxp;
5135         __perf_event_task_sched_out(child_ctx);
5136
5137         /*
5138          * Take the context lock here so that if find_get_context is
5139          * reading child->perf_event_ctxp, we wait until it has
5140          * incremented the context's refcount before we do put_ctx below.
5141          */
5142         raw_spin_lock(&child_ctx->lock);
5143         child->perf_event_ctxp = NULL;
5144         /*
5145          * If this context is a clone; unclone it so it can't get
5146          * swapped to another process while we're removing all
5147          * the events from it.
5148          */
5149         unclone_ctx(child_ctx);
5150         update_context_time(child_ctx);
5151         raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
5152
5153         /*
5154          * Report the task dead after unscheduling the events so that we
5155          * won't get any samples after PERF_RECORD_EXIT. We can however still
5156          * get a few PERF_RECORD_READ events.
5157          */
5158         perf_event_task(child, child_ctx, 0);
5159
5160         /*
5161          * We can recurse on the same lock type through:
5162          *
5163          *   __perf_event_exit_task()
5164          *     sync_child_event()
5165          *       fput(parent_event->filp)
5166          *         perf_release()
5167          *           mutex_lock(&ctx->mutex)
5168          *
5169          * But since its the parent context it won't be the same instance.
5170          */
5171         mutex_lock_nested(&child_ctx->mutex, SINGLE_DEPTH_NESTING);
5172
5173 again:
5174         list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups,
5175                                  group_entry)
5176                 __perf_event_exit_task(child_event, child_ctx, child);
5177
5178         list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups,
5179                                  group_entry)
5180                 __perf_event_exit_task(child_event, child_ctx, child);
5181
5182         /*
5183          * If the last event was a group event, it will have appended all
5184          * its siblings to the list, but we obtained 'tmp' before that which
5185          * will still point to the list head terminating the iteration.
5186          */
5187         if (!list_empty(&child_ctx->pinned_groups) ||
5188             !list_empty(&child_ctx->flexible_groups))
5189                 goto again;
5190
5191         mutex_unlock(&child_ctx->mutex);
5192
5193         put_ctx(child_ctx);
5194 }
5195
5196 static void perf_free_event(struct perf_event *event,
5197                             struct perf_event_context *ctx)
5198 {
5199         struct perf_event *parent = event->parent;
5200
5201         if (WARN_ON_ONCE(!parent))
5202                 return;
5203
5204         mutex_lock(&parent->child_mutex);
5205         list_del_init(&event->child_list);
5206         mutex_unlock(&parent->child_mutex);
5207
5208         fput(parent->filp);
5209
5210         list_del_event(event, ctx);
5211         free_event(event);
5212 }
5213
5214 /*
5215  * free an unexposed, unused context as created by inheritance by
5216  * init_task below, used by fork() in case of fail.
5217  */
5218 void perf_event_free_task(struct task_struct *task)
5219 {
5220         struct perf_event_context *ctx = task->perf_event_ctxp;
5221         struct perf_event *event, *tmp;
5222
5223         if (!ctx)
5224                 return;
5225
5226         mutex_lock(&ctx->mutex);
5227 again:
5228         list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
5229                 perf_free_event(event, ctx);
5230
5231         list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
5232                                  group_entry)
5233                 perf_free_event(event, ctx);
5234
5235         if (!list_empty(&ctx->pinned_groups) ||
5236             !list_empty(&ctx->flexible_groups))
5237                 goto again;
5238
5239         mutex_unlock(&ctx->mutex);
5240
5241         put_ctx(ctx);
5242 }
5243
5244 static int
5245 inherit_task_group(struct perf_event *event, struct task_struct *parent,
5246                    struct perf_event_context *parent_ctx,
5247                    struct task_struct *child,
5248                    int *inherited_all)
5249 {
5250         int ret;
5251         struct perf_event_context *child_ctx = child->perf_event_ctxp;
5252
5253         if (!event->attr.inherit) {
5254                 *inherited_all = 0;
5255                 return 0;
5256         }
5257
5258         if (!child_ctx) {
5259                 /*
5260                  * This is executed from the parent task context, so
5261                  * inherit events that have been marked for cloning.
5262                  * First allocate and initialize a context for the
5263                  * child.
5264                  */
5265
5266                 child_ctx = kzalloc(sizeof(struct perf_event_context),
5267                                     GFP_KERNEL);
5268                 if (!child_ctx)
5269                         return -ENOMEM;
5270
5271                 __perf_event_init_context(child_ctx, child);
5272                 child->perf_event_ctxp = child_ctx;
5273                 get_task_struct(child);
5274         }
5275
5276         ret = inherit_group(event, parent, parent_ctx,
5277                             child, child_ctx);
5278
5279         if (ret)
5280                 *inherited_all = 0;
5281
5282         return ret;
5283 }
5284
5285
5286 /*
5287  * Initialize the perf_event context in task_struct
5288  */
5289 int perf_event_init_task(struct task_struct *child)
5290 {
5291         struct perf_event_context *child_ctx, *parent_ctx;
5292         struct perf_event_context *cloned_ctx;
5293         struct perf_event *event;
5294         struct task_struct *parent = current;
5295         int inherited_all = 1;
5296         int ret = 0;
5297
5298         child->perf_event_ctxp = NULL;
5299
5300         mutex_init(&child->perf_event_mutex);
5301         INIT_LIST_HEAD(&child->perf_event_list);
5302
5303         if (likely(!parent->perf_event_ctxp))
5304                 return 0;
5305
5306         /*
5307          * If the parent's context is a clone, pin it so it won't get
5308          * swapped under us.
5309          */
5310         parent_ctx = perf_pin_task_context(parent);
5311
5312         /*
5313          * No need to check if parent_ctx != NULL here; since we saw
5314          * it non-NULL earlier, the only reason for it to become NULL
5315          * is if we exit, and since we're currently in the middle of
5316          * a fork we can't be exiting at the same time.
5317          */
5318
5319         /*
5320          * Lock the parent list. No need to lock the child - not PID
5321          * hashed yet and not running, so nobody can access it.
5322          */
5323         mutex_lock(&parent_ctx->mutex);
5324
5325         /*
5326          * We dont have to disable NMIs - we are only looking at
5327          * the list, not manipulating it:
5328          */
5329         list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
5330                 ret = inherit_task_group(event, parent, parent_ctx, child,
5331                                          &inherited_all);
5332                 if (ret)
5333                         break;
5334         }
5335
5336         list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
5337                 ret = inherit_task_group(event, parent, parent_ctx, child,
5338                                          &inherited_all);
5339                 if (ret)
5340                         break;
5341         }
5342
5343         child_ctx = child->perf_event_ctxp;
5344
5345         if (child_ctx && inherited_all) {
5346                 /*
5347                  * Mark the child context as a clone of the parent
5348                  * context, or of whatever the parent is a clone of.
5349                  * Note that if the parent is a clone, it could get
5350                  * uncloned at any point, but that doesn't matter
5351                  * because the list of events and the generation
5352                  * count can't have changed since we took the mutex.
5353                  */
5354                 cloned_ctx = rcu_dereference(parent_ctx->parent_ctx);
5355                 if (cloned_ctx) {
5356                         child_ctx->parent_ctx = cloned_ctx;
5357                         child_ctx->parent_gen = parent_ctx->parent_gen;
5358                 } else {
5359                         child_ctx->parent_ctx = parent_ctx;
5360                         child_ctx->parent_gen = parent_ctx->generation;
5361                 }
5362                 get_ctx(child_ctx->parent_ctx);
5363         }
5364
5365         mutex_unlock(&parent_ctx->mutex);
5366
5367         perf_unpin_context(parent_ctx);
5368
5369         return ret;
5370 }
5371
5372 static void __cpuinit perf_event_init_cpu(int cpu)
5373 {
5374         struct perf_cpu_context *cpuctx;
5375
5376         cpuctx = &per_cpu(perf_cpu_context, cpu);
5377         __perf_event_init_context(&cpuctx->ctx, NULL);
5378
5379         spin_lock(&perf_resource_lock);
5380         cpuctx->max_pertask = perf_max_events - perf_reserved_percpu;
5381         spin_unlock(&perf_resource_lock);
5382
5383         hw_perf_event_setup(cpu);
5384 }
5385
5386 #ifdef CONFIG_HOTPLUG_CPU
5387 static void __perf_event_exit_cpu(void *info)
5388 {
5389         struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
5390         struct perf_event_context *ctx = &cpuctx->ctx;
5391         struct perf_event *event, *tmp;
5392
5393         list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
5394                 __perf_event_remove_from_context(event);
5395         list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry)
5396                 __perf_event_remove_from_context(event);
5397 }
5398 static void perf_event_exit_cpu(int cpu)
5399 {
5400         struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
5401         struct perf_event_context *ctx = &cpuctx->ctx;
5402
5403         mutex_lock(&ctx->mutex);
5404         smp_call_function_single(cpu, __perf_event_exit_cpu, NULL, 1);
5405         mutex_unlock(&ctx->mutex);
5406 }
5407 #else
5408 static inline void perf_event_exit_cpu(int cpu) { }
5409 #endif
5410
5411 static int __cpuinit
5412 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
5413 {
5414         unsigned int cpu = (long)hcpu;
5415
5416         switch (action) {
5417
5418         case CPU_UP_PREPARE:
5419         case CPU_UP_PREPARE_FROZEN:
5420                 perf_event_init_cpu(cpu);
5421                 break;
5422
5423         case CPU_ONLINE:
5424         case CPU_ONLINE_FROZEN:
5425                 hw_perf_event_setup_online(cpu);
5426                 break;
5427
5428         case CPU_DOWN_PREPARE:
5429         case CPU_DOWN_PREPARE_FROZEN:
5430                 perf_event_exit_cpu(cpu);
5431                 break;
5432
5433         default:
5434                 break;
5435         }
5436
5437         return NOTIFY_OK;
5438 }
5439
5440 /*
5441  * This has to have a higher priority than migration_notifier in sched.c.
5442  */
5443 static struct notifier_block __cpuinitdata perf_cpu_nb = {
5444         .notifier_call          = perf_cpu_notify,
5445         .priority               = 20,
5446 };
5447
5448 void __init perf_event_init(void)
5449 {
5450         perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE,
5451                         (void *)(long)smp_processor_id());
5452         perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_ONLINE,
5453                         (void *)(long)smp_processor_id());
5454         register_cpu_notifier(&perf_cpu_nb);
5455 }
5456
5457 static ssize_t perf_show_reserve_percpu(struct sysdev_class *class, char *buf)
5458 {
5459         return sprintf(buf, "%d\n", perf_reserved_percpu);
5460 }
5461
5462 static ssize_t
5463 perf_set_reserve_percpu(struct sysdev_class *class,
5464                         const char *buf,
5465                         size_t count)
5466 {
5467         struct perf_cpu_context *cpuctx;
5468         unsigned long val;
5469         int err, cpu, mpt;
5470
5471         err = strict_strtoul(buf, 10, &val);
5472         if (err)
5473                 return err;
5474         if (val > perf_max_events)
5475                 return -EINVAL;
5476
5477         spin_lock(&perf_resource_lock);
5478         perf_reserved_percpu = val;
5479         for_each_online_cpu(cpu) {
5480                 cpuctx = &per_cpu(perf_cpu_context, cpu);
5481                 raw_spin_lock_irq(&cpuctx->ctx.lock);
5482                 mpt = min(perf_max_events - cpuctx->ctx.nr_events,
5483                           perf_max_events - perf_reserved_percpu);
5484                 cpuctx->max_pertask = mpt;
5485                 raw_spin_unlock_irq(&cpuctx->ctx.lock);
5486         }
5487         spin_unlock(&perf_resource_lock);
5488
5489         return count;
5490 }
5491
5492 static ssize_t perf_show_overcommit(struct sysdev_class *class, char *buf)
5493 {
5494         return sprintf(buf, "%d\n", perf_overcommit);
5495 }
5496
5497 static ssize_t
5498 perf_set_overcommit(struct sysdev_class *class, const char *buf, size_t count)
5499 {
5500         unsigned long val;
5501         int err;
5502
5503         err = strict_strtoul(buf, 10, &val);
5504         if (err)
5505                 return err;
5506         if (val > 1)
5507                 return -EINVAL;
5508
5509         spin_lock(&perf_resource_lock);
5510         perf_overcommit = val;
5511         spin_unlock(&perf_resource_lock);
5512
5513         return count;
5514 }
5515
5516 static SYSDEV_CLASS_ATTR(
5517                                 reserve_percpu,
5518                                 0644,
5519                                 perf_show_reserve_percpu,
5520                                 perf_set_reserve_percpu
5521                         );
5522
5523 static SYSDEV_CLASS_ATTR(
5524                                 overcommit,
5525                                 0644,
5526                                 perf_show_overcommit,
5527                                 perf_set_overcommit
5528                         );
5529
5530 static struct attribute *perfclass_attrs[] = {
5531         &attr_reserve_percpu.attr,
5532         &attr_overcommit.attr,
5533         NULL
5534 };
5535
5536 static struct attribute_group perfclass_attr_group = {
5537         .attrs                  = perfclass_attrs,
5538         .name                   = "perf_events",
5539 };
5540
5541 static int __init perf_event_sysfs_init(void)
5542 {
5543         return sysfs_create_group(&cpu_sysdev_class.kset.kobj,
5544                                   &perfclass_attr_group);
5545 }
5546 device_initcall(perf_event_sysfs_init);