d5899b62b2769854c04e5447483e31525791d791
[linux-2.6.git] / kernel / perf_counter.c
1 /*
2  * Performance counter 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/hardirq.h>
24 #include <linux/rculist.h>
25 #include <linux/uaccess.h>
26 #include <linux/syscalls.h>
27 #include <linux/anon_inodes.h>
28 #include <linux/kernel_stat.h>
29 #include <linux/perf_counter.h>
30
31 #include <asm/irq_regs.h>
32
33 /*
34  * Each CPU has a list of per CPU counters:
35  */
36 DEFINE_PER_CPU(struct perf_cpu_context, perf_cpu_context);
37
38 int perf_max_counters __read_mostly = 1;
39 static int perf_reserved_percpu __read_mostly;
40 static int perf_overcommit __read_mostly = 1;
41
42 static atomic_t nr_counters __read_mostly;
43 static atomic_t nr_mmap_counters __read_mostly;
44 static atomic_t nr_comm_counters __read_mostly;
45 static atomic_t nr_task_counters __read_mostly;
46
47 /*
48  * perf counter paranoia level:
49  *  -1 - not paranoid at all
50  *   0 - disallow raw tracepoint access for unpriv
51  *   1 - disallow cpu counters for unpriv
52  *   2 - disallow kernel profiling for unpriv
53  */
54 int sysctl_perf_counter_paranoid __read_mostly = 1;
55
56 static inline bool perf_paranoid_tracepoint_raw(void)
57 {
58         return sysctl_perf_counter_paranoid > -1;
59 }
60
61 static inline bool perf_paranoid_cpu(void)
62 {
63         return sysctl_perf_counter_paranoid > 0;
64 }
65
66 static inline bool perf_paranoid_kernel(void)
67 {
68         return sysctl_perf_counter_paranoid > 1;
69 }
70
71 int sysctl_perf_counter_mlock __read_mostly = 512; /* 'free' kb per user */
72
73 /*
74  * max perf counter sample rate
75  */
76 int sysctl_perf_counter_sample_rate __read_mostly = 100000;
77
78 static atomic64_t perf_counter_id;
79
80 /*
81  * Lock for (sysadmin-configurable) counter reservations:
82  */
83 static DEFINE_SPINLOCK(perf_resource_lock);
84
85 /*
86  * Architecture provided APIs - weak aliases:
87  */
88 extern __weak const struct pmu *hw_perf_counter_init(struct perf_counter *counter)
89 {
90         return NULL;
91 }
92
93 void __weak hw_perf_disable(void)               { barrier(); }
94 void __weak hw_perf_enable(void)                { barrier(); }
95
96 void __weak hw_perf_counter_setup(int cpu)      { barrier(); }
97 void __weak hw_perf_counter_setup_online(int cpu)       { barrier(); }
98
99 int __weak
100 hw_perf_group_sched_in(struct perf_counter *group_leader,
101                struct perf_cpu_context *cpuctx,
102                struct perf_counter_context *ctx, int cpu)
103 {
104         return 0;
105 }
106
107 void __weak perf_counter_print_debug(void)      { }
108
109 static DEFINE_PER_CPU(int, perf_disable_count);
110
111 void __perf_disable(void)
112 {
113         __get_cpu_var(perf_disable_count)++;
114 }
115
116 bool __perf_enable(void)
117 {
118         return !--__get_cpu_var(perf_disable_count);
119 }
120
121 void perf_disable(void)
122 {
123         __perf_disable();
124         hw_perf_disable();
125 }
126
127 void perf_enable(void)
128 {
129         if (__perf_enable())
130                 hw_perf_enable();
131 }
132
133 static void get_ctx(struct perf_counter_context *ctx)
134 {
135         WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
136 }
137
138 static void free_ctx(struct rcu_head *head)
139 {
140         struct perf_counter_context *ctx;
141
142         ctx = container_of(head, struct perf_counter_context, rcu_head);
143         kfree(ctx);
144 }
145
146 static void put_ctx(struct perf_counter_context *ctx)
147 {
148         if (atomic_dec_and_test(&ctx->refcount)) {
149                 if (ctx->parent_ctx)
150                         put_ctx(ctx->parent_ctx);
151                 if (ctx->task)
152                         put_task_struct(ctx->task);
153                 call_rcu(&ctx->rcu_head, free_ctx);
154         }
155 }
156
157 static void unclone_ctx(struct perf_counter_context *ctx)
158 {
159         if (ctx->parent_ctx) {
160                 put_ctx(ctx->parent_ctx);
161                 ctx->parent_ctx = NULL;
162         }
163 }
164
165 /*
166  * If we inherit counters we want to return the parent counter id
167  * to userspace.
168  */
169 static u64 primary_counter_id(struct perf_counter *counter)
170 {
171         u64 id = counter->id;
172
173         if (counter->parent)
174                 id = counter->parent->id;
175
176         return id;
177 }
178
179 /*
180  * Get the perf_counter_context for a task and lock it.
181  * This has to cope with with the fact that until it is locked,
182  * the context could get moved to another task.
183  */
184 static struct perf_counter_context *
185 perf_lock_task_context(struct task_struct *task, unsigned long *flags)
186 {
187         struct perf_counter_context *ctx;
188
189         rcu_read_lock();
190  retry:
191         ctx = rcu_dereference(task->perf_counter_ctxp);
192         if (ctx) {
193                 /*
194                  * If this context is a clone of another, it might
195                  * get swapped for another underneath us by
196                  * perf_counter_task_sched_out, though the
197                  * rcu_read_lock() protects us from any context
198                  * getting freed.  Lock the context and check if it
199                  * got swapped before we could get the lock, and retry
200                  * if so.  If we locked the right context, then it
201                  * can't get swapped on us any more.
202                  */
203                 spin_lock_irqsave(&ctx->lock, *flags);
204                 if (ctx != rcu_dereference(task->perf_counter_ctxp)) {
205                         spin_unlock_irqrestore(&ctx->lock, *flags);
206                         goto retry;
207                 }
208
209                 if (!atomic_inc_not_zero(&ctx->refcount)) {
210                         spin_unlock_irqrestore(&ctx->lock, *flags);
211                         ctx = NULL;
212                 }
213         }
214         rcu_read_unlock();
215         return ctx;
216 }
217
218 /*
219  * Get the context for a task and increment its pin_count so it
220  * can't get swapped to another task.  This also increments its
221  * reference count so that the context can't get freed.
222  */
223 static struct perf_counter_context *perf_pin_task_context(struct task_struct *task)
224 {
225         struct perf_counter_context *ctx;
226         unsigned long flags;
227
228         ctx = perf_lock_task_context(task, &flags);
229         if (ctx) {
230                 ++ctx->pin_count;
231                 spin_unlock_irqrestore(&ctx->lock, flags);
232         }
233         return ctx;
234 }
235
236 static void perf_unpin_context(struct perf_counter_context *ctx)
237 {
238         unsigned long flags;
239
240         spin_lock_irqsave(&ctx->lock, flags);
241         --ctx->pin_count;
242         spin_unlock_irqrestore(&ctx->lock, flags);
243         put_ctx(ctx);
244 }
245
246 /*
247  * Add a counter from the lists for its context.
248  * Must be called with ctx->mutex and ctx->lock held.
249  */
250 static void
251 list_add_counter(struct perf_counter *counter, struct perf_counter_context *ctx)
252 {
253         struct perf_counter *group_leader = counter->group_leader;
254
255         /*
256          * Depending on whether it is a standalone or sibling counter,
257          * add it straight to the context's counter list, or to the group
258          * leader's sibling list:
259          */
260         if (group_leader == counter)
261                 list_add_tail(&counter->list_entry, &ctx->counter_list);
262         else {
263                 list_add_tail(&counter->list_entry, &group_leader->sibling_list);
264                 group_leader->nr_siblings++;
265         }
266
267         list_add_rcu(&counter->event_entry, &ctx->event_list);
268         ctx->nr_counters++;
269         if (counter->attr.inherit_stat)
270                 ctx->nr_stat++;
271 }
272
273 /*
274  * Remove a counter from the lists for its context.
275  * Must be called with ctx->mutex and ctx->lock held.
276  */
277 static void
278 list_del_counter(struct perf_counter *counter, struct perf_counter_context *ctx)
279 {
280         struct perf_counter *sibling, *tmp;
281
282         if (list_empty(&counter->list_entry))
283                 return;
284         ctx->nr_counters--;
285         if (counter->attr.inherit_stat)
286                 ctx->nr_stat--;
287
288         list_del_init(&counter->list_entry);
289         list_del_rcu(&counter->event_entry);
290
291         if (counter->group_leader != counter)
292                 counter->group_leader->nr_siblings--;
293
294         /*
295          * If this was a group counter with sibling counters then
296          * upgrade the siblings to singleton counters by adding them
297          * to the context list directly:
298          */
299         list_for_each_entry_safe(sibling, tmp,
300                                  &counter->sibling_list, list_entry) {
301
302                 list_move_tail(&sibling->list_entry, &ctx->counter_list);
303                 sibling->group_leader = sibling;
304         }
305 }
306
307 static void
308 counter_sched_out(struct perf_counter *counter,
309                   struct perf_cpu_context *cpuctx,
310                   struct perf_counter_context *ctx)
311 {
312         if (counter->state != PERF_COUNTER_STATE_ACTIVE)
313                 return;
314
315         counter->state = PERF_COUNTER_STATE_INACTIVE;
316         if (counter->pending_disable) {
317                 counter->pending_disable = 0;
318                 counter->state = PERF_COUNTER_STATE_OFF;
319         }
320         counter->tstamp_stopped = ctx->time;
321         counter->pmu->disable(counter);
322         counter->oncpu = -1;
323
324         if (!is_software_counter(counter))
325                 cpuctx->active_oncpu--;
326         ctx->nr_active--;
327         if (counter->attr.exclusive || !cpuctx->active_oncpu)
328                 cpuctx->exclusive = 0;
329 }
330
331 static void
332 group_sched_out(struct perf_counter *group_counter,
333                 struct perf_cpu_context *cpuctx,
334                 struct perf_counter_context *ctx)
335 {
336         struct perf_counter *counter;
337
338         if (group_counter->state != PERF_COUNTER_STATE_ACTIVE)
339                 return;
340
341         counter_sched_out(group_counter, cpuctx, ctx);
342
343         /*
344          * Schedule out siblings (if any):
345          */
346         list_for_each_entry(counter, &group_counter->sibling_list, list_entry)
347                 counter_sched_out(counter, cpuctx, ctx);
348
349         if (group_counter->attr.exclusive)
350                 cpuctx->exclusive = 0;
351 }
352
353 /*
354  * Cross CPU call to remove a performance counter
355  *
356  * We disable the counter on the hardware level first. After that we
357  * remove it from the context list.
358  */
359 static void __perf_counter_remove_from_context(void *info)
360 {
361         struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
362         struct perf_counter *counter = info;
363         struct perf_counter_context *ctx = counter->ctx;
364
365         /*
366          * If this is a task context, we need to check whether it is
367          * the current task context of this cpu. If not it has been
368          * scheduled out before the smp call arrived.
369          */
370         if (ctx->task && cpuctx->task_ctx != ctx)
371                 return;
372
373         spin_lock(&ctx->lock);
374         /*
375          * Protect the list operation against NMI by disabling the
376          * counters on a global level.
377          */
378         perf_disable();
379
380         counter_sched_out(counter, cpuctx, ctx);
381
382         list_del_counter(counter, ctx);
383
384         if (!ctx->task) {
385                 /*
386                  * Allow more per task counters with respect to the
387                  * reservation:
388                  */
389                 cpuctx->max_pertask =
390                         min(perf_max_counters - ctx->nr_counters,
391                             perf_max_counters - perf_reserved_percpu);
392         }
393
394         perf_enable();
395         spin_unlock(&ctx->lock);
396 }
397
398
399 /*
400  * Remove the counter from a task's (or a CPU's) list of counters.
401  *
402  * Must be called with ctx->mutex held.
403  *
404  * CPU counters are removed with a smp call. For task counters we only
405  * call when the task is on a CPU.
406  *
407  * If counter->ctx is a cloned context, callers must make sure that
408  * every task struct that counter->ctx->task could possibly point to
409  * remains valid.  This is OK when called from perf_release since
410  * that only calls us on the top-level context, which can't be a clone.
411  * When called from perf_counter_exit_task, it's OK because the
412  * context has been detached from its task.
413  */
414 static void perf_counter_remove_from_context(struct perf_counter *counter)
415 {
416         struct perf_counter_context *ctx = counter->ctx;
417         struct task_struct *task = ctx->task;
418
419         if (!task) {
420                 /*
421                  * Per cpu counters are removed via an smp call and
422                  * the removal is always sucessful.
423                  */
424                 smp_call_function_single(counter->cpu,
425                                          __perf_counter_remove_from_context,
426                                          counter, 1);
427                 return;
428         }
429
430 retry:
431         task_oncpu_function_call(task, __perf_counter_remove_from_context,
432                                  counter);
433
434         spin_lock_irq(&ctx->lock);
435         /*
436          * If the context is active we need to retry the smp call.
437          */
438         if (ctx->nr_active && !list_empty(&counter->list_entry)) {
439                 spin_unlock_irq(&ctx->lock);
440                 goto retry;
441         }
442
443         /*
444          * The lock prevents that this context is scheduled in so we
445          * can remove the counter safely, if the call above did not
446          * succeed.
447          */
448         if (!list_empty(&counter->list_entry)) {
449                 list_del_counter(counter, ctx);
450         }
451         spin_unlock_irq(&ctx->lock);
452 }
453
454 static inline u64 perf_clock(void)
455 {
456         return cpu_clock(smp_processor_id());
457 }
458
459 /*
460  * Update the record of the current time in a context.
461  */
462 static void update_context_time(struct perf_counter_context *ctx)
463 {
464         u64 now = perf_clock();
465
466         ctx->time += now - ctx->timestamp;
467         ctx->timestamp = now;
468 }
469
470 /*
471  * Update the total_time_enabled and total_time_running fields for a counter.
472  */
473 static void update_counter_times(struct perf_counter *counter)
474 {
475         struct perf_counter_context *ctx = counter->ctx;
476         u64 run_end;
477
478         if (counter->state < PERF_COUNTER_STATE_INACTIVE ||
479             counter->group_leader->state < PERF_COUNTER_STATE_INACTIVE)
480                 return;
481
482         counter->total_time_enabled = ctx->time - counter->tstamp_enabled;
483
484         if (counter->state == PERF_COUNTER_STATE_INACTIVE)
485                 run_end = counter->tstamp_stopped;
486         else
487                 run_end = ctx->time;
488
489         counter->total_time_running = run_end - counter->tstamp_running;
490 }
491
492 /*
493  * Update total_time_enabled and total_time_running for all counters in a group.
494  */
495 static void update_group_times(struct perf_counter *leader)
496 {
497         struct perf_counter *counter;
498
499         update_counter_times(leader);
500         list_for_each_entry(counter, &leader->sibling_list, list_entry)
501                 update_counter_times(counter);
502 }
503
504 /*
505  * Cross CPU call to disable a performance counter
506  */
507 static void __perf_counter_disable(void *info)
508 {
509         struct perf_counter *counter = info;
510         struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
511         struct perf_counter_context *ctx = counter->ctx;
512
513         /*
514          * If this is a per-task counter, need to check whether this
515          * counter's task is the current task on this cpu.
516          */
517         if (ctx->task && cpuctx->task_ctx != ctx)
518                 return;
519
520         spin_lock(&ctx->lock);
521
522         /*
523          * If the counter is on, turn it off.
524          * If it is in error state, leave it in error state.
525          */
526         if (counter->state >= PERF_COUNTER_STATE_INACTIVE) {
527                 update_context_time(ctx);
528                 update_group_times(counter);
529                 if (counter == counter->group_leader)
530                         group_sched_out(counter, cpuctx, ctx);
531                 else
532                         counter_sched_out(counter, cpuctx, ctx);
533                 counter->state = PERF_COUNTER_STATE_OFF;
534         }
535
536         spin_unlock(&ctx->lock);
537 }
538
539 /*
540  * Disable a counter.
541  *
542  * If counter->ctx is a cloned context, callers must make sure that
543  * every task struct that counter->ctx->task could possibly point to
544  * remains valid.  This condition is satisifed when called through
545  * perf_counter_for_each_child or perf_counter_for_each because they
546  * hold the top-level counter's child_mutex, so any descendant that
547  * goes to exit will block in sync_child_counter.
548  * When called from perf_pending_counter it's OK because counter->ctx
549  * is the current context on this CPU and preemption is disabled,
550  * hence we can't get into perf_counter_task_sched_out for this context.
551  */
552 static void perf_counter_disable(struct perf_counter *counter)
553 {
554         struct perf_counter_context *ctx = counter->ctx;
555         struct task_struct *task = ctx->task;
556
557         if (!task) {
558                 /*
559                  * Disable the counter on the cpu that it's on
560                  */
561                 smp_call_function_single(counter->cpu, __perf_counter_disable,
562                                          counter, 1);
563                 return;
564         }
565
566  retry:
567         task_oncpu_function_call(task, __perf_counter_disable, counter);
568
569         spin_lock_irq(&ctx->lock);
570         /*
571          * If the counter is still active, we need to retry the cross-call.
572          */
573         if (counter->state == PERF_COUNTER_STATE_ACTIVE) {
574                 spin_unlock_irq(&ctx->lock);
575                 goto retry;
576         }
577
578         /*
579          * Since we have the lock this context can't be scheduled
580          * in, so we can change the state safely.
581          */
582         if (counter->state == PERF_COUNTER_STATE_INACTIVE) {
583                 update_group_times(counter);
584                 counter->state = PERF_COUNTER_STATE_OFF;
585         }
586
587         spin_unlock_irq(&ctx->lock);
588 }
589
590 static int
591 counter_sched_in(struct perf_counter *counter,
592                  struct perf_cpu_context *cpuctx,
593                  struct perf_counter_context *ctx,
594                  int cpu)
595 {
596         if (counter->state <= PERF_COUNTER_STATE_OFF)
597                 return 0;
598
599         counter->state = PERF_COUNTER_STATE_ACTIVE;
600         counter->oncpu = cpu;   /* TODO: put 'cpu' into cpuctx->cpu */
601         /*
602          * The new state must be visible before we turn it on in the hardware:
603          */
604         smp_wmb();
605
606         if (counter->pmu->enable(counter)) {
607                 counter->state = PERF_COUNTER_STATE_INACTIVE;
608                 counter->oncpu = -1;
609                 return -EAGAIN;
610         }
611
612         counter->tstamp_running += ctx->time - counter->tstamp_stopped;
613
614         if (!is_software_counter(counter))
615                 cpuctx->active_oncpu++;
616         ctx->nr_active++;
617
618         if (counter->attr.exclusive)
619                 cpuctx->exclusive = 1;
620
621         return 0;
622 }
623
624 static int
625 group_sched_in(struct perf_counter *group_counter,
626                struct perf_cpu_context *cpuctx,
627                struct perf_counter_context *ctx,
628                int cpu)
629 {
630         struct perf_counter *counter, *partial_group;
631         int ret;
632
633         if (group_counter->state == PERF_COUNTER_STATE_OFF)
634                 return 0;
635
636         ret = hw_perf_group_sched_in(group_counter, cpuctx, ctx, cpu);
637         if (ret)
638                 return ret < 0 ? ret : 0;
639
640         if (counter_sched_in(group_counter, cpuctx, ctx, cpu))
641                 return -EAGAIN;
642
643         /*
644          * Schedule in siblings as one group (if any):
645          */
646         list_for_each_entry(counter, &group_counter->sibling_list, list_entry) {
647                 if (counter_sched_in(counter, cpuctx, ctx, cpu)) {
648                         partial_group = counter;
649                         goto group_error;
650                 }
651         }
652
653         return 0;
654
655 group_error:
656         /*
657          * Groups can be scheduled in as one unit only, so undo any
658          * partial group before returning:
659          */
660         list_for_each_entry(counter, &group_counter->sibling_list, list_entry) {
661                 if (counter == partial_group)
662                         break;
663                 counter_sched_out(counter, cpuctx, ctx);
664         }
665         counter_sched_out(group_counter, cpuctx, ctx);
666
667         return -EAGAIN;
668 }
669
670 /*
671  * Return 1 for a group consisting entirely of software counters,
672  * 0 if the group contains any hardware counters.
673  */
674 static int is_software_only_group(struct perf_counter *leader)
675 {
676         struct perf_counter *counter;
677
678         if (!is_software_counter(leader))
679                 return 0;
680
681         list_for_each_entry(counter, &leader->sibling_list, list_entry)
682                 if (!is_software_counter(counter))
683                         return 0;
684
685         return 1;
686 }
687
688 /*
689  * Work out whether we can put this counter group on the CPU now.
690  */
691 static int group_can_go_on(struct perf_counter *counter,
692                            struct perf_cpu_context *cpuctx,
693                            int can_add_hw)
694 {
695         /*
696          * Groups consisting entirely of software counters can always go on.
697          */
698         if (is_software_only_group(counter))
699                 return 1;
700         /*
701          * If an exclusive group is already on, no other hardware
702          * counters can go on.
703          */
704         if (cpuctx->exclusive)
705                 return 0;
706         /*
707          * If this group is exclusive and there are already
708          * counters on the CPU, it can't go on.
709          */
710         if (counter->attr.exclusive && cpuctx->active_oncpu)
711                 return 0;
712         /*
713          * Otherwise, try to add it if all previous groups were able
714          * to go on.
715          */
716         return can_add_hw;
717 }
718
719 static void add_counter_to_ctx(struct perf_counter *counter,
720                                struct perf_counter_context *ctx)
721 {
722         list_add_counter(counter, ctx);
723         counter->tstamp_enabled = ctx->time;
724         counter->tstamp_running = ctx->time;
725         counter->tstamp_stopped = ctx->time;
726 }
727
728 /*
729  * Cross CPU call to install and enable a performance counter
730  *
731  * Must be called with ctx->mutex held
732  */
733 static void __perf_install_in_context(void *info)
734 {
735         struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
736         struct perf_counter *counter = info;
737         struct perf_counter_context *ctx = counter->ctx;
738         struct perf_counter *leader = counter->group_leader;
739         int cpu = smp_processor_id();
740         int err;
741
742         /*
743          * If this is a task context, we need to check whether it is
744          * the current task context of this cpu. If not it has been
745          * scheduled out before the smp call arrived.
746          * Or possibly this is the right context but it isn't
747          * on this cpu because it had no counters.
748          */
749         if (ctx->task && cpuctx->task_ctx != ctx) {
750                 if (cpuctx->task_ctx || ctx->task != current)
751                         return;
752                 cpuctx->task_ctx = ctx;
753         }
754
755         spin_lock(&ctx->lock);
756         ctx->is_active = 1;
757         update_context_time(ctx);
758
759         /*
760          * Protect the list operation against NMI by disabling the
761          * counters on a global level. NOP for non NMI based counters.
762          */
763         perf_disable();
764
765         add_counter_to_ctx(counter, ctx);
766
767         /*
768          * Don't put the counter on if it is disabled or if
769          * it is in a group and the group isn't on.
770          */
771         if (counter->state != PERF_COUNTER_STATE_INACTIVE ||
772             (leader != counter && leader->state != PERF_COUNTER_STATE_ACTIVE))
773                 goto unlock;
774
775         /*
776          * An exclusive counter can't go on if there are already active
777          * hardware counters, and no hardware counter can go on if there
778          * is already an exclusive counter on.
779          */
780         if (!group_can_go_on(counter, cpuctx, 1))
781                 err = -EEXIST;
782         else
783                 err = counter_sched_in(counter, cpuctx, ctx, cpu);
784
785         if (err) {
786                 /*
787                  * This counter couldn't go on.  If it is in a group
788                  * then we have to pull the whole group off.
789                  * If the counter group is pinned then put it in error state.
790                  */
791                 if (leader != counter)
792                         group_sched_out(leader, cpuctx, ctx);
793                 if (leader->attr.pinned) {
794                         update_group_times(leader);
795                         leader->state = PERF_COUNTER_STATE_ERROR;
796                 }
797         }
798
799         if (!err && !ctx->task && cpuctx->max_pertask)
800                 cpuctx->max_pertask--;
801
802  unlock:
803         perf_enable();
804
805         spin_unlock(&ctx->lock);
806 }
807
808 /*
809  * Attach a performance counter to a context
810  *
811  * First we add the counter to the list with the hardware enable bit
812  * in counter->hw_config cleared.
813  *
814  * If the counter is attached to a task which is on a CPU we use a smp
815  * call to enable it in the task context. The task might have been
816  * scheduled away, but we check this in the smp call again.
817  *
818  * Must be called with ctx->mutex held.
819  */
820 static void
821 perf_install_in_context(struct perf_counter_context *ctx,
822                         struct perf_counter *counter,
823                         int cpu)
824 {
825         struct task_struct *task = ctx->task;
826
827         if (!task) {
828                 /*
829                  * Per cpu counters are installed via an smp call and
830                  * the install is always sucessful.
831                  */
832                 smp_call_function_single(cpu, __perf_install_in_context,
833                                          counter, 1);
834                 return;
835         }
836
837 retry:
838         task_oncpu_function_call(task, __perf_install_in_context,
839                                  counter);
840
841         spin_lock_irq(&ctx->lock);
842         /*
843          * we need to retry the smp call.
844          */
845         if (ctx->is_active && list_empty(&counter->list_entry)) {
846                 spin_unlock_irq(&ctx->lock);
847                 goto retry;
848         }
849
850         /*
851          * The lock prevents that this context is scheduled in so we
852          * can add the counter safely, if it the call above did not
853          * succeed.
854          */
855         if (list_empty(&counter->list_entry))
856                 add_counter_to_ctx(counter, ctx);
857         spin_unlock_irq(&ctx->lock);
858 }
859
860 /*
861  * Put a counter into inactive state and update time fields.
862  * Enabling the leader of a group effectively enables all
863  * the group members that aren't explicitly disabled, so we
864  * have to update their ->tstamp_enabled also.
865  * Note: this works for group members as well as group leaders
866  * since the non-leader members' sibling_lists will be empty.
867  */
868 static void __perf_counter_mark_enabled(struct perf_counter *counter,
869                                         struct perf_counter_context *ctx)
870 {
871         struct perf_counter *sub;
872
873         counter->state = PERF_COUNTER_STATE_INACTIVE;
874         counter->tstamp_enabled = ctx->time - counter->total_time_enabled;
875         list_for_each_entry(sub, &counter->sibling_list, list_entry)
876                 if (sub->state >= PERF_COUNTER_STATE_INACTIVE)
877                         sub->tstamp_enabled =
878                                 ctx->time - sub->total_time_enabled;
879 }
880
881 /*
882  * Cross CPU call to enable a performance counter
883  */
884 static void __perf_counter_enable(void *info)
885 {
886         struct perf_counter *counter = info;
887         struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
888         struct perf_counter_context *ctx = counter->ctx;
889         struct perf_counter *leader = counter->group_leader;
890         int err;
891
892         /*
893          * If this is a per-task counter, need to check whether this
894          * counter's task is the current task on this cpu.
895          */
896         if (ctx->task && cpuctx->task_ctx != ctx) {
897                 if (cpuctx->task_ctx || ctx->task != current)
898                         return;
899                 cpuctx->task_ctx = ctx;
900         }
901
902         spin_lock(&ctx->lock);
903         ctx->is_active = 1;
904         update_context_time(ctx);
905
906         if (counter->state >= PERF_COUNTER_STATE_INACTIVE)
907                 goto unlock;
908         __perf_counter_mark_enabled(counter, ctx);
909
910         /*
911          * If the counter is in a group and isn't the group leader,
912          * then don't put it on unless the group is on.
913          */
914         if (leader != counter && leader->state != PERF_COUNTER_STATE_ACTIVE)
915                 goto unlock;
916
917         if (!group_can_go_on(counter, cpuctx, 1)) {
918                 err = -EEXIST;
919         } else {
920                 perf_disable();
921                 if (counter == leader)
922                         err = group_sched_in(counter, cpuctx, ctx,
923                                              smp_processor_id());
924                 else
925                         err = counter_sched_in(counter, cpuctx, ctx,
926                                                smp_processor_id());
927                 perf_enable();
928         }
929
930         if (err) {
931                 /*
932                  * If this counter can't go on and it's part of a
933                  * group, then the whole group has to come off.
934                  */
935                 if (leader != counter)
936                         group_sched_out(leader, cpuctx, ctx);
937                 if (leader->attr.pinned) {
938                         update_group_times(leader);
939                         leader->state = PERF_COUNTER_STATE_ERROR;
940                 }
941         }
942
943  unlock:
944         spin_unlock(&ctx->lock);
945 }
946
947 /*
948  * Enable a counter.
949  *
950  * If counter->ctx is a cloned context, callers must make sure that
951  * every task struct that counter->ctx->task could possibly point to
952  * remains valid.  This condition is satisfied when called through
953  * perf_counter_for_each_child or perf_counter_for_each as described
954  * for perf_counter_disable.
955  */
956 static void perf_counter_enable(struct perf_counter *counter)
957 {
958         struct perf_counter_context *ctx = counter->ctx;
959         struct task_struct *task = ctx->task;
960
961         if (!task) {
962                 /*
963                  * Enable the counter on the cpu that it's on
964                  */
965                 smp_call_function_single(counter->cpu, __perf_counter_enable,
966                                          counter, 1);
967                 return;
968         }
969
970         spin_lock_irq(&ctx->lock);
971         if (counter->state >= PERF_COUNTER_STATE_INACTIVE)
972                 goto out;
973
974         /*
975          * If the counter is in error state, clear that first.
976          * That way, if we see the counter in error state below, we
977          * know that it has gone back into error state, as distinct
978          * from the task having been scheduled away before the
979          * cross-call arrived.
980          */
981         if (counter->state == PERF_COUNTER_STATE_ERROR)
982                 counter->state = PERF_COUNTER_STATE_OFF;
983
984  retry:
985         spin_unlock_irq(&ctx->lock);
986         task_oncpu_function_call(task, __perf_counter_enable, counter);
987
988         spin_lock_irq(&ctx->lock);
989
990         /*
991          * If the context is active and the counter is still off,
992          * we need to retry the cross-call.
993          */
994         if (ctx->is_active && counter->state == PERF_COUNTER_STATE_OFF)
995                 goto retry;
996
997         /*
998          * Since we have the lock this context can't be scheduled
999          * in, so we can change the state safely.
1000          */
1001         if (counter->state == PERF_COUNTER_STATE_OFF)
1002                 __perf_counter_mark_enabled(counter, ctx);
1003
1004  out:
1005         spin_unlock_irq(&ctx->lock);
1006 }
1007
1008 static int perf_counter_refresh(struct perf_counter *counter, int refresh)
1009 {
1010         /*
1011          * not supported on inherited counters
1012          */
1013         if (counter->attr.inherit)
1014                 return -EINVAL;
1015
1016         atomic_add(refresh, &counter->event_limit);
1017         perf_counter_enable(counter);
1018
1019         return 0;
1020 }
1021
1022 void __perf_counter_sched_out(struct perf_counter_context *ctx,
1023                               struct perf_cpu_context *cpuctx)
1024 {
1025         struct perf_counter *counter;
1026
1027         spin_lock(&ctx->lock);
1028         ctx->is_active = 0;
1029         if (likely(!ctx->nr_counters))
1030                 goto out;
1031         update_context_time(ctx);
1032
1033         perf_disable();
1034         if (ctx->nr_active) {
1035                 list_for_each_entry(counter, &ctx->counter_list, list_entry) {
1036                         if (counter != counter->group_leader)
1037                                 counter_sched_out(counter, cpuctx, ctx);
1038                         else
1039                                 group_sched_out(counter, cpuctx, ctx);
1040                 }
1041         }
1042         perf_enable();
1043  out:
1044         spin_unlock(&ctx->lock);
1045 }
1046
1047 /*
1048  * Test whether two contexts are equivalent, i.e. whether they
1049  * have both been cloned from the same version of the same context
1050  * and they both have the same number of enabled counters.
1051  * If the number of enabled counters is the same, then the set
1052  * of enabled counters should be the same, because these are both
1053  * inherited contexts, therefore we can't access individual counters
1054  * in them directly with an fd; we can only enable/disable all
1055  * counters via prctl, or enable/disable all counters in a family
1056  * via ioctl, which will have the same effect on both contexts.
1057  */
1058 static int context_equiv(struct perf_counter_context *ctx1,
1059                          struct perf_counter_context *ctx2)
1060 {
1061         return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
1062                 && ctx1->parent_gen == ctx2->parent_gen
1063                 && !ctx1->pin_count && !ctx2->pin_count;
1064 }
1065
1066 static void __perf_counter_read(void *counter);
1067
1068 static void __perf_counter_sync_stat(struct perf_counter *counter,
1069                                      struct perf_counter *next_counter)
1070 {
1071         u64 value;
1072
1073         if (!counter->attr.inherit_stat)
1074                 return;
1075
1076         /*
1077          * Update the counter value, we cannot use perf_counter_read()
1078          * because we're in the middle of a context switch and have IRQs
1079          * disabled, which upsets smp_call_function_single(), however
1080          * we know the counter must be on the current CPU, therefore we
1081          * don't need to use it.
1082          */
1083         switch (counter->state) {
1084         case PERF_COUNTER_STATE_ACTIVE:
1085                 __perf_counter_read(counter);
1086                 break;
1087
1088         case PERF_COUNTER_STATE_INACTIVE:
1089                 update_counter_times(counter);
1090                 break;
1091
1092         default:
1093                 break;
1094         }
1095
1096         /*
1097          * In order to keep per-task stats reliable we need to flip the counter
1098          * values when we flip the contexts.
1099          */
1100         value = atomic64_read(&next_counter->count);
1101         value = atomic64_xchg(&counter->count, value);
1102         atomic64_set(&next_counter->count, value);
1103
1104         swap(counter->total_time_enabled, next_counter->total_time_enabled);
1105         swap(counter->total_time_running, next_counter->total_time_running);
1106
1107         /*
1108          * Since we swizzled the values, update the user visible data too.
1109          */
1110         perf_counter_update_userpage(counter);
1111         perf_counter_update_userpage(next_counter);
1112 }
1113
1114 #define list_next_entry(pos, member) \
1115         list_entry(pos->member.next, typeof(*pos), member)
1116
1117 static void perf_counter_sync_stat(struct perf_counter_context *ctx,
1118                                    struct perf_counter_context *next_ctx)
1119 {
1120         struct perf_counter *counter, *next_counter;
1121
1122         if (!ctx->nr_stat)
1123                 return;
1124
1125         counter = list_first_entry(&ctx->event_list,
1126                                    struct perf_counter, event_entry);
1127
1128         next_counter = list_first_entry(&next_ctx->event_list,
1129                                         struct perf_counter, event_entry);
1130
1131         while (&counter->event_entry != &ctx->event_list &&
1132                &next_counter->event_entry != &next_ctx->event_list) {
1133
1134                 __perf_counter_sync_stat(counter, next_counter);
1135
1136                 counter = list_next_entry(counter, event_entry);
1137                 next_counter = list_next_entry(next_counter, event_entry);
1138         }
1139 }
1140
1141 /*
1142  * Called from scheduler to remove the counters of the current task,
1143  * with interrupts disabled.
1144  *
1145  * We stop each counter and update the counter value in counter->count.
1146  *
1147  * This does not protect us against NMI, but disable()
1148  * sets the disabled bit in the control field of counter _before_
1149  * accessing the counter control register. If a NMI hits, then it will
1150  * not restart the counter.
1151  */
1152 void perf_counter_task_sched_out(struct task_struct *task,
1153                                  struct task_struct *next, int cpu)
1154 {
1155         struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
1156         struct perf_counter_context *ctx = task->perf_counter_ctxp;
1157         struct perf_counter_context *next_ctx;
1158         struct perf_counter_context *parent;
1159         struct pt_regs *regs;
1160         int do_switch = 1;
1161
1162         regs = task_pt_regs(task);
1163         perf_swcounter_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, regs, 0);
1164
1165         if (likely(!ctx || !cpuctx->task_ctx))
1166                 return;
1167
1168         update_context_time(ctx);
1169
1170         rcu_read_lock();
1171         parent = rcu_dereference(ctx->parent_ctx);
1172         next_ctx = next->perf_counter_ctxp;
1173         if (parent && next_ctx &&
1174             rcu_dereference(next_ctx->parent_ctx) == parent) {
1175                 /*
1176                  * Looks like the two contexts are clones, so we might be
1177                  * able to optimize the context switch.  We lock both
1178                  * contexts and check that they are clones under the
1179                  * lock (including re-checking that neither has been
1180                  * uncloned in the meantime).  It doesn't matter which
1181                  * order we take the locks because no other cpu could
1182                  * be trying to lock both of these tasks.
1183                  */
1184                 spin_lock(&ctx->lock);
1185                 spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
1186                 if (context_equiv(ctx, next_ctx)) {
1187                         /*
1188                          * XXX do we need a memory barrier of sorts
1189                          * wrt to rcu_dereference() of perf_counter_ctxp
1190                          */
1191                         task->perf_counter_ctxp = next_ctx;
1192                         next->perf_counter_ctxp = ctx;
1193                         ctx->task = next;
1194                         next_ctx->task = task;
1195                         do_switch = 0;
1196
1197                         perf_counter_sync_stat(ctx, next_ctx);
1198                 }
1199                 spin_unlock(&next_ctx->lock);
1200                 spin_unlock(&ctx->lock);
1201         }
1202         rcu_read_unlock();
1203
1204         if (do_switch) {
1205                 __perf_counter_sched_out(ctx, cpuctx);
1206                 cpuctx->task_ctx = NULL;
1207         }
1208 }
1209
1210 /*
1211  * Called with IRQs disabled
1212  */
1213 static void __perf_counter_task_sched_out(struct perf_counter_context *ctx)
1214 {
1215         struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1216
1217         if (!cpuctx->task_ctx)
1218                 return;
1219
1220         if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
1221                 return;
1222
1223         __perf_counter_sched_out(ctx, cpuctx);
1224         cpuctx->task_ctx = NULL;
1225 }
1226
1227 /*
1228  * Called with IRQs disabled
1229  */
1230 static void perf_counter_cpu_sched_out(struct perf_cpu_context *cpuctx)
1231 {
1232         __perf_counter_sched_out(&cpuctx->ctx, cpuctx);
1233 }
1234
1235 static void
1236 __perf_counter_sched_in(struct perf_counter_context *ctx,
1237                         struct perf_cpu_context *cpuctx, int cpu)
1238 {
1239         struct perf_counter *counter;
1240         int can_add_hw = 1;
1241
1242         spin_lock(&ctx->lock);
1243         ctx->is_active = 1;
1244         if (likely(!ctx->nr_counters))
1245                 goto out;
1246
1247         ctx->timestamp = perf_clock();
1248
1249         perf_disable();
1250
1251         /*
1252          * First go through the list and put on any pinned groups
1253          * in order to give them the best chance of going on.
1254          */
1255         list_for_each_entry(counter, &ctx->counter_list, list_entry) {
1256                 if (counter->state <= PERF_COUNTER_STATE_OFF ||
1257                     !counter->attr.pinned)
1258                         continue;
1259                 if (counter->cpu != -1 && counter->cpu != cpu)
1260                         continue;
1261
1262                 if (counter != counter->group_leader)
1263                         counter_sched_in(counter, cpuctx, ctx, cpu);
1264                 else {
1265                         if (group_can_go_on(counter, cpuctx, 1))
1266                                 group_sched_in(counter, cpuctx, ctx, cpu);
1267                 }
1268
1269                 /*
1270                  * If this pinned group hasn't been scheduled,
1271                  * put it in error state.
1272                  */
1273                 if (counter->state == PERF_COUNTER_STATE_INACTIVE) {
1274                         update_group_times(counter);
1275                         counter->state = PERF_COUNTER_STATE_ERROR;
1276                 }
1277         }
1278
1279         list_for_each_entry(counter, &ctx->counter_list, list_entry) {
1280                 /*
1281                  * Ignore counters in OFF or ERROR state, and
1282                  * ignore pinned counters since we did them already.
1283                  */
1284                 if (counter->state <= PERF_COUNTER_STATE_OFF ||
1285                     counter->attr.pinned)
1286                         continue;
1287
1288                 /*
1289                  * Listen to the 'cpu' scheduling filter constraint
1290                  * of counters:
1291                  */
1292                 if (counter->cpu != -1 && counter->cpu != cpu)
1293                         continue;
1294
1295                 if (counter != counter->group_leader) {
1296                         if (counter_sched_in(counter, cpuctx, ctx, cpu))
1297                                 can_add_hw = 0;
1298                 } else {
1299                         if (group_can_go_on(counter, cpuctx, can_add_hw)) {
1300                                 if (group_sched_in(counter, cpuctx, ctx, cpu))
1301                                         can_add_hw = 0;
1302                         }
1303                 }
1304         }
1305         perf_enable();
1306  out:
1307         spin_unlock(&ctx->lock);
1308 }
1309
1310 /*
1311  * Called from scheduler to add the counters of the current task
1312  * with interrupts disabled.
1313  *
1314  * We restore the counter value and then enable it.
1315  *
1316  * This does not protect us against NMI, but enable()
1317  * sets the enabled bit in the control field of counter _before_
1318  * accessing the counter control register. If a NMI hits, then it will
1319  * keep the counter running.
1320  */
1321 void perf_counter_task_sched_in(struct task_struct *task, int cpu)
1322 {
1323         struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
1324         struct perf_counter_context *ctx = task->perf_counter_ctxp;
1325
1326         if (likely(!ctx))
1327                 return;
1328         if (cpuctx->task_ctx == ctx)
1329                 return;
1330         __perf_counter_sched_in(ctx, cpuctx, cpu);
1331         cpuctx->task_ctx = ctx;
1332 }
1333
1334 static void perf_counter_cpu_sched_in(struct perf_cpu_context *cpuctx, int cpu)
1335 {
1336         struct perf_counter_context *ctx = &cpuctx->ctx;
1337
1338         __perf_counter_sched_in(ctx, cpuctx, cpu);
1339 }
1340
1341 #define MAX_INTERRUPTS (~0ULL)
1342
1343 static void perf_log_throttle(struct perf_counter *counter, int enable);
1344
1345 static void perf_adjust_period(struct perf_counter *counter, u64 events)
1346 {
1347         struct hw_perf_counter *hwc = &counter->hw;
1348         u64 period, sample_period;
1349         s64 delta;
1350
1351         events *= hwc->sample_period;
1352         period = div64_u64(events, counter->attr.sample_freq);
1353
1354         delta = (s64)(period - hwc->sample_period);
1355         delta = (delta + 7) / 8; /* low pass filter */
1356
1357         sample_period = hwc->sample_period + delta;
1358
1359         if (!sample_period)
1360                 sample_period = 1;
1361
1362         hwc->sample_period = sample_period;
1363 }
1364
1365 static void perf_ctx_adjust_freq(struct perf_counter_context *ctx)
1366 {
1367         struct perf_counter *counter;
1368         struct hw_perf_counter *hwc;
1369         u64 interrupts, freq;
1370
1371         spin_lock(&ctx->lock);
1372         list_for_each_entry(counter, &ctx->counter_list, list_entry) {
1373                 if (counter->state != PERF_COUNTER_STATE_ACTIVE)
1374                         continue;
1375
1376                 hwc = &counter->hw;
1377
1378                 interrupts = hwc->interrupts;
1379                 hwc->interrupts = 0;
1380
1381                 /*
1382                  * unthrottle counters on the tick
1383                  */
1384                 if (interrupts == MAX_INTERRUPTS) {
1385                         perf_log_throttle(counter, 1);
1386                         counter->pmu->unthrottle(counter);
1387                         interrupts = 2*sysctl_perf_counter_sample_rate/HZ;
1388                 }
1389
1390                 if (!counter->attr.freq || !counter->attr.sample_freq)
1391                         continue;
1392
1393                 /*
1394                  * if the specified freq < HZ then we need to skip ticks
1395                  */
1396                 if (counter->attr.sample_freq < HZ) {
1397                         freq = counter->attr.sample_freq;
1398
1399                         hwc->freq_count += freq;
1400                         hwc->freq_interrupts += interrupts;
1401
1402                         if (hwc->freq_count < HZ)
1403                                 continue;
1404
1405                         interrupts = hwc->freq_interrupts;
1406                         hwc->freq_interrupts = 0;
1407                         hwc->freq_count -= HZ;
1408                 } else
1409                         freq = HZ;
1410
1411                 perf_adjust_period(counter, freq * interrupts);
1412
1413                 /*
1414                  * In order to avoid being stalled by an (accidental) huge
1415                  * sample period, force reset the sample period if we didn't
1416                  * get any events in this freq period.
1417                  */
1418                 if (!interrupts) {
1419                         perf_disable();
1420                         counter->pmu->disable(counter);
1421                         atomic64_set(&hwc->period_left, 0);
1422                         counter->pmu->enable(counter);
1423                         perf_enable();
1424                 }
1425         }
1426         spin_unlock(&ctx->lock);
1427 }
1428
1429 /*
1430  * Round-robin a context's counters:
1431  */
1432 static void rotate_ctx(struct perf_counter_context *ctx)
1433 {
1434         struct perf_counter *counter;
1435
1436         if (!ctx->nr_counters)
1437                 return;
1438
1439         spin_lock(&ctx->lock);
1440         /*
1441          * Rotate the first entry last (works just fine for group counters too):
1442          */
1443         perf_disable();
1444         list_for_each_entry(counter, &ctx->counter_list, list_entry) {
1445                 list_move_tail(&counter->list_entry, &ctx->counter_list);
1446                 break;
1447         }
1448         perf_enable();
1449
1450         spin_unlock(&ctx->lock);
1451 }
1452
1453 void perf_counter_task_tick(struct task_struct *curr, int cpu)
1454 {
1455         struct perf_cpu_context *cpuctx;
1456         struct perf_counter_context *ctx;
1457
1458         if (!atomic_read(&nr_counters))
1459                 return;
1460
1461         cpuctx = &per_cpu(perf_cpu_context, cpu);
1462         ctx = curr->perf_counter_ctxp;
1463
1464         perf_ctx_adjust_freq(&cpuctx->ctx);
1465         if (ctx)
1466                 perf_ctx_adjust_freq(ctx);
1467
1468         perf_counter_cpu_sched_out(cpuctx);
1469         if (ctx)
1470                 __perf_counter_task_sched_out(ctx);
1471
1472         rotate_ctx(&cpuctx->ctx);
1473         if (ctx)
1474                 rotate_ctx(ctx);
1475
1476         perf_counter_cpu_sched_in(cpuctx, cpu);
1477         if (ctx)
1478                 perf_counter_task_sched_in(curr, cpu);
1479 }
1480
1481 /*
1482  * Enable all of a task's counters that have been marked enable-on-exec.
1483  * This expects task == current.
1484  */
1485 static void perf_counter_enable_on_exec(struct task_struct *task)
1486 {
1487         struct perf_counter_context *ctx;
1488         struct perf_counter *counter;
1489         unsigned long flags;
1490         int enabled = 0;
1491
1492         local_irq_save(flags);
1493         ctx = task->perf_counter_ctxp;
1494         if (!ctx || !ctx->nr_counters)
1495                 goto out;
1496
1497         __perf_counter_task_sched_out(ctx);
1498
1499         spin_lock(&ctx->lock);
1500
1501         list_for_each_entry(counter, &ctx->counter_list, list_entry) {
1502                 if (!counter->attr.enable_on_exec)
1503                         continue;
1504                 counter->attr.enable_on_exec = 0;
1505                 if (counter->state >= PERF_COUNTER_STATE_INACTIVE)
1506                         continue;
1507                 __perf_counter_mark_enabled(counter, ctx);
1508                 enabled = 1;
1509         }
1510
1511         /*
1512          * Unclone this context if we enabled any counter.
1513          */
1514         if (enabled)
1515                 unclone_ctx(ctx);
1516
1517         spin_unlock(&ctx->lock);
1518
1519         perf_counter_task_sched_in(task, smp_processor_id());
1520  out:
1521         local_irq_restore(flags);
1522 }
1523
1524 /*
1525  * Cross CPU call to read the hardware counter
1526  */
1527 static void __perf_counter_read(void *info)
1528 {
1529         struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1530         struct perf_counter *counter = info;
1531         struct perf_counter_context *ctx = counter->ctx;
1532         unsigned long flags;
1533
1534         /*
1535          * If this is a task context, we need to check whether it is
1536          * the current task context of this cpu.  If not it has been
1537          * scheduled out before the smp call arrived.  In that case
1538          * counter->count would have been updated to a recent sample
1539          * when the counter was scheduled out.
1540          */
1541         if (ctx->task && cpuctx->task_ctx != ctx)
1542                 return;
1543
1544         local_irq_save(flags);
1545         if (ctx->is_active)
1546                 update_context_time(ctx);
1547         counter->pmu->read(counter);
1548         update_counter_times(counter);
1549         local_irq_restore(flags);
1550 }
1551
1552 static u64 perf_counter_read(struct perf_counter *counter)
1553 {
1554         /*
1555          * If counter is enabled and currently active on a CPU, update the
1556          * value in the counter structure:
1557          */
1558         if (counter->state == PERF_COUNTER_STATE_ACTIVE) {
1559                 smp_call_function_single(counter->oncpu,
1560                                          __perf_counter_read, counter, 1);
1561         } else if (counter->state == PERF_COUNTER_STATE_INACTIVE) {
1562                 update_counter_times(counter);
1563         }
1564
1565         return atomic64_read(&counter->count);
1566 }
1567
1568 /*
1569  * Initialize the perf_counter context in a task_struct:
1570  */
1571 static void
1572 __perf_counter_init_context(struct perf_counter_context *ctx,
1573                             struct task_struct *task)
1574 {
1575         memset(ctx, 0, sizeof(*ctx));
1576         spin_lock_init(&ctx->lock);
1577         mutex_init(&ctx->mutex);
1578         INIT_LIST_HEAD(&ctx->counter_list);
1579         INIT_LIST_HEAD(&ctx->event_list);
1580         atomic_set(&ctx->refcount, 1);
1581         ctx->task = task;
1582 }
1583
1584 static struct perf_counter_context *find_get_context(pid_t pid, int cpu)
1585 {
1586         struct perf_counter_context *ctx;
1587         struct perf_cpu_context *cpuctx;
1588         struct task_struct *task;
1589         unsigned long flags;
1590         int err;
1591
1592         /*
1593          * If cpu is not a wildcard then this is a percpu counter:
1594          */
1595         if (cpu != -1) {
1596                 /* Must be root to operate on a CPU counter: */
1597                 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
1598                         return ERR_PTR(-EACCES);
1599
1600                 if (cpu < 0 || cpu > num_possible_cpus())
1601                         return ERR_PTR(-EINVAL);
1602
1603                 /*
1604                  * We could be clever and allow to attach a counter to an
1605                  * offline CPU and activate it when the CPU comes up, but
1606                  * that's for later.
1607                  */
1608                 if (!cpu_isset(cpu, cpu_online_map))
1609                         return ERR_PTR(-ENODEV);
1610
1611                 cpuctx = &per_cpu(perf_cpu_context, cpu);
1612                 ctx = &cpuctx->ctx;
1613                 get_ctx(ctx);
1614
1615                 return ctx;
1616         }
1617
1618         rcu_read_lock();
1619         if (!pid)
1620                 task = current;
1621         else
1622                 task = find_task_by_vpid(pid);
1623         if (task)
1624                 get_task_struct(task);
1625         rcu_read_unlock();
1626
1627         if (!task)
1628                 return ERR_PTR(-ESRCH);
1629
1630         /*
1631          * Can't attach counters to a dying task.
1632          */
1633         err = -ESRCH;
1634         if (task->flags & PF_EXITING)
1635                 goto errout;
1636
1637         /* Reuse ptrace permission checks for now. */
1638         err = -EACCES;
1639         if (!ptrace_may_access(task, PTRACE_MODE_READ))
1640                 goto errout;
1641
1642  retry:
1643         ctx = perf_lock_task_context(task, &flags);
1644         if (ctx) {
1645                 unclone_ctx(ctx);
1646                 spin_unlock_irqrestore(&ctx->lock, flags);
1647         }
1648
1649         if (!ctx) {
1650                 ctx = kmalloc(sizeof(struct perf_counter_context), GFP_KERNEL);
1651                 err = -ENOMEM;
1652                 if (!ctx)
1653                         goto errout;
1654                 __perf_counter_init_context(ctx, task);
1655                 get_ctx(ctx);
1656                 if (cmpxchg(&task->perf_counter_ctxp, NULL, ctx)) {
1657                         /*
1658                          * We raced with some other task; use
1659                          * the context they set.
1660                          */
1661                         kfree(ctx);
1662                         goto retry;
1663                 }
1664                 get_task_struct(task);
1665         }
1666
1667         put_task_struct(task);
1668         return ctx;
1669
1670  errout:
1671         put_task_struct(task);
1672         return ERR_PTR(err);
1673 }
1674
1675 static void free_counter_rcu(struct rcu_head *head)
1676 {
1677         struct perf_counter *counter;
1678
1679         counter = container_of(head, struct perf_counter, rcu_head);
1680         if (counter->ns)
1681                 put_pid_ns(counter->ns);
1682         kfree(counter);
1683 }
1684
1685 static void perf_pending_sync(struct perf_counter *counter);
1686
1687 static void free_counter(struct perf_counter *counter)
1688 {
1689         perf_pending_sync(counter);
1690
1691         if (!counter->parent) {
1692                 atomic_dec(&nr_counters);
1693                 if (counter->attr.mmap)
1694                         atomic_dec(&nr_mmap_counters);
1695                 if (counter->attr.comm)
1696                         atomic_dec(&nr_comm_counters);
1697                 if (counter->attr.task)
1698                         atomic_dec(&nr_task_counters);
1699         }
1700
1701         if (counter->output) {
1702                 fput(counter->output->filp);
1703                 counter->output = NULL;
1704         }
1705
1706         if (counter->destroy)
1707                 counter->destroy(counter);
1708
1709         put_ctx(counter->ctx);
1710         call_rcu(&counter->rcu_head, free_counter_rcu);
1711 }
1712
1713 /*
1714  * Called when the last reference to the file is gone.
1715  */
1716 static int perf_release(struct inode *inode, struct file *file)
1717 {
1718         struct perf_counter *counter = file->private_data;
1719         struct perf_counter_context *ctx = counter->ctx;
1720
1721         file->private_data = NULL;
1722
1723         WARN_ON_ONCE(ctx->parent_ctx);
1724         mutex_lock(&ctx->mutex);
1725         perf_counter_remove_from_context(counter);
1726         mutex_unlock(&ctx->mutex);
1727
1728         mutex_lock(&counter->owner->perf_counter_mutex);
1729         list_del_init(&counter->owner_entry);
1730         mutex_unlock(&counter->owner->perf_counter_mutex);
1731         put_task_struct(counter->owner);
1732
1733         free_counter(counter);
1734
1735         return 0;
1736 }
1737
1738 static int perf_counter_read_size(struct perf_counter *counter)
1739 {
1740         int entry = sizeof(u64); /* value */
1741         int size = 0;
1742         int nr = 1;
1743
1744         if (counter->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1745                 size += sizeof(u64);
1746
1747         if (counter->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1748                 size += sizeof(u64);
1749
1750         if (counter->attr.read_format & PERF_FORMAT_ID)
1751                 entry += sizeof(u64);
1752
1753         if (counter->attr.read_format & PERF_FORMAT_GROUP) {
1754                 nr += counter->group_leader->nr_siblings;
1755                 size += sizeof(u64);
1756         }
1757
1758         size += entry * nr;
1759
1760         return size;
1761 }
1762
1763 static u64 perf_counter_read_value(struct perf_counter *counter)
1764 {
1765         struct perf_counter *child;
1766         u64 total = 0;
1767
1768         total += perf_counter_read(counter);
1769         list_for_each_entry(child, &counter->child_list, child_list)
1770                 total += perf_counter_read(child);
1771
1772         return total;
1773 }
1774
1775 static int perf_counter_read_entry(struct perf_counter *counter,
1776                                    u64 read_format, char __user *buf)
1777 {
1778         int n = 0, count = 0;
1779         u64 values[2];
1780
1781         values[n++] = perf_counter_read_value(counter);
1782         if (read_format & PERF_FORMAT_ID)
1783                 values[n++] = primary_counter_id(counter);
1784
1785         count = n * sizeof(u64);
1786
1787         if (copy_to_user(buf, values, count))
1788                 return -EFAULT;
1789
1790         return count;
1791 }
1792
1793 static int perf_counter_read_group(struct perf_counter *counter,
1794                                    u64 read_format, char __user *buf)
1795 {
1796         struct perf_counter *leader = counter->group_leader, *sub;
1797         int n = 0, size = 0, err = -EFAULT;
1798         u64 values[3];
1799
1800         values[n++] = 1 + leader->nr_siblings;
1801         if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
1802                 values[n++] = leader->total_time_enabled +
1803                         atomic64_read(&leader->child_total_time_enabled);
1804         }
1805         if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
1806                 values[n++] = leader->total_time_running +
1807                         atomic64_read(&leader->child_total_time_running);
1808         }
1809
1810         size = n * sizeof(u64);
1811
1812         if (copy_to_user(buf, values, size))
1813                 return -EFAULT;
1814
1815         err = perf_counter_read_entry(leader, read_format, buf + size);
1816         if (err < 0)
1817                 return err;
1818
1819         size += err;
1820
1821         list_for_each_entry(sub, &leader->sibling_list, list_entry) {
1822                 err = perf_counter_read_entry(sub, read_format,
1823                                 buf + size);
1824                 if (err < 0)
1825                         return err;
1826
1827                 size += err;
1828         }
1829
1830         return size;
1831 }
1832
1833 static int perf_counter_read_one(struct perf_counter *counter,
1834                                  u64 read_format, char __user *buf)
1835 {
1836         u64 values[4];
1837         int n = 0;
1838
1839         values[n++] = perf_counter_read_value(counter);
1840         if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
1841                 values[n++] = counter->total_time_enabled +
1842                         atomic64_read(&counter->child_total_time_enabled);
1843         }
1844         if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
1845                 values[n++] = counter->total_time_running +
1846                         atomic64_read(&counter->child_total_time_running);
1847         }
1848         if (read_format & PERF_FORMAT_ID)
1849                 values[n++] = primary_counter_id(counter);
1850
1851         if (copy_to_user(buf, values, n * sizeof(u64)))
1852                 return -EFAULT;
1853
1854         return n * sizeof(u64);
1855 }
1856
1857 /*
1858  * Read the performance counter - simple non blocking version for now
1859  */
1860 static ssize_t
1861 perf_read_hw(struct perf_counter *counter, char __user *buf, size_t count)
1862 {
1863         u64 read_format = counter->attr.read_format;
1864         int ret;
1865
1866         /*
1867          * Return end-of-file for a read on a counter that is in
1868          * error state (i.e. because it was pinned but it couldn't be
1869          * scheduled on to the CPU at some point).
1870          */
1871         if (counter->state == PERF_COUNTER_STATE_ERROR)
1872                 return 0;
1873
1874         if (count < perf_counter_read_size(counter))
1875                 return -ENOSPC;
1876
1877         WARN_ON_ONCE(counter->ctx->parent_ctx);
1878         mutex_lock(&counter->child_mutex);
1879         if (read_format & PERF_FORMAT_GROUP)
1880                 ret = perf_counter_read_group(counter, read_format, buf);
1881         else
1882                 ret = perf_counter_read_one(counter, read_format, buf);
1883         mutex_unlock(&counter->child_mutex);
1884
1885         return ret;
1886 }
1887
1888 static ssize_t
1889 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
1890 {
1891         struct perf_counter *counter = file->private_data;
1892
1893         return perf_read_hw(counter, buf, count);
1894 }
1895
1896 static unsigned int perf_poll(struct file *file, poll_table *wait)
1897 {
1898         struct perf_counter *counter = file->private_data;
1899         struct perf_mmap_data *data;
1900         unsigned int events = POLL_HUP;
1901
1902         rcu_read_lock();
1903         data = rcu_dereference(counter->data);
1904         if (data)
1905                 events = atomic_xchg(&data->poll, 0);
1906         rcu_read_unlock();
1907
1908         poll_wait(file, &counter->waitq, wait);
1909
1910         return events;
1911 }
1912
1913 static void perf_counter_reset(struct perf_counter *counter)
1914 {
1915         (void)perf_counter_read(counter);
1916         atomic64_set(&counter->count, 0);
1917         perf_counter_update_userpage(counter);
1918 }
1919
1920 /*
1921  * Holding the top-level counter's child_mutex means that any
1922  * descendant process that has inherited this counter will block
1923  * in sync_child_counter if it goes to exit, thus satisfying the
1924  * task existence requirements of perf_counter_enable/disable.
1925  */
1926 static void perf_counter_for_each_child(struct perf_counter *counter,
1927                                         void (*func)(struct perf_counter *))
1928 {
1929         struct perf_counter *child;
1930
1931         WARN_ON_ONCE(counter->ctx->parent_ctx);
1932         mutex_lock(&counter->child_mutex);
1933         func(counter);
1934         list_for_each_entry(child, &counter->child_list, child_list)
1935                 func(child);
1936         mutex_unlock(&counter->child_mutex);
1937 }
1938
1939 static void perf_counter_for_each(struct perf_counter *counter,
1940                                   void (*func)(struct perf_counter *))
1941 {
1942         struct perf_counter_context *ctx = counter->ctx;
1943         struct perf_counter *sibling;
1944
1945         WARN_ON_ONCE(ctx->parent_ctx);
1946         mutex_lock(&ctx->mutex);
1947         counter = counter->group_leader;
1948
1949         perf_counter_for_each_child(counter, func);
1950         func(counter);
1951         list_for_each_entry(sibling, &counter->sibling_list, list_entry)
1952                 perf_counter_for_each_child(counter, func);
1953         mutex_unlock(&ctx->mutex);
1954 }
1955
1956 static int perf_counter_period(struct perf_counter *counter, u64 __user *arg)
1957 {
1958         struct perf_counter_context *ctx = counter->ctx;
1959         unsigned long size;
1960         int ret = 0;
1961         u64 value;
1962
1963         if (!counter->attr.sample_period)
1964                 return -EINVAL;
1965
1966         size = copy_from_user(&value, arg, sizeof(value));
1967         if (size != sizeof(value))
1968                 return -EFAULT;
1969
1970         if (!value)
1971                 return -EINVAL;
1972
1973         spin_lock_irq(&ctx->lock);
1974         if (counter->attr.freq) {
1975                 if (value > sysctl_perf_counter_sample_rate) {
1976                         ret = -EINVAL;
1977                         goto unlock;
1978                 }
1979
1980                 counter->attr.sample_freq = value;
1981         } else {
1982                 counter->attr.sample_period = value;
1983                 counter->hw.sample_period = value;
1984         }
1985 unlock:
1986         spin_unlock_irq(&ctx->lock);
1987
1988         return ret;
1989 }
1990
1991 int perf_counter_set_output(struct perf_counter *counter, int output_fd);
1992
1993 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1994 {
1995         struct perf_counter *counter = file->private_data;
1996         void (*func)(struct perf_counter *);
1997         u32 flags = arg;
1998
1999         switch (cmd) {
2000         case PERF_COUNTER_IOC_ENABLE:
2001                 func = perf_counter_enable;
2002                 break;
2003         case PERF_COUNTER_IOC_DISABLE:
2004                 func = perf_counter_disable;
2005                 break;
2006         case PERF_COUNTER_IOC_RESET:
2007                 func = perf_counter_reset;
2008                 break;
2009
2010         case PERF_COUNTER_IOC_REFRESH:
2011                 return perf_counter_refresh(counter, arg);
2012
2013         case PERF_COUNTER_IOC_PERIOD:
2014                 return perf_counter_period(counter, (u64 __user *)arg);
2015
2016         case PERF_COUNTER_IOC_SET_OUTPUT:
2017                 return perf_counter_set_output(counter, arg);
2018
2019         default:
2020                 return -ENOTTY;
2021         }
2022
2023         if (flags & PERF_IOC_FLAG_GROUP)
2024                 perf_counter_for_each(counter, func);
2025         else
2026                 perf_counter_for_each_child(counter, func);
2027
2028         return 0;
2029 }
2030
2031 int perf_counter_task_enable(void)
2032 {
2033         struct perf_counter *counter;
2034
2035         mutex_lock(&current->perf_counter_mutex);
2036         list_for_each_entry(counter, &current->perf_counter_list, owner_entry)
2037                 perf_counter_for_each_child(counter, perf_counter_enable);
2038         mutex_unlock(&current->perf_counter_mutex);
2039
2040         return 0;
2041 }
2042
2043 int perf_counter_task_disable(void)
2044 {
2045         struct perf_counter *counter;
2046
2047         mutex_lock(&current->perf_counter_mutex);
2048         list_for_each_entry(counter, &current->perf_counter_list, owner_entry)
2049                 perf_counter_for_each_child(counter, perf_counter_disable);
2050         mutex_unlock(&current->perf_counter_mutex);
2051
2052         return 0;
2053 }
2054
2055 #ifndef PERF_COUNTER_INDEX_OFFSET
2056 # define PERF_COUNTER_INDEX_OFFSET 0
2057 #endif
2058
2059 static int perf_counter_index(struct perf_counter *counter)
2060 {
2061         if (counter->state != PERF_COUNTER_STATE_ACTIVE)
2062                 return 0;
2063
2064         return counter->hw.idx + 1 - PERF_COUNTER_INDEX_OFFSET;
2065 }
2066
2067 /*
2068  * Callers need to ensure there can be no nesting of this function, otherwise
2069  * the seqlock logic goes bad. We can not serialize this because the arch
2070  * code calls this from NMI context.
2071  */
2072 void perf_counter_update_userpage(struct perf_counter *counter)
2073 {
2074         struct perf_counter_mmap_page *userpg;
2075         struct perf_mmap_data *data;
2076
2077         rcu_read_lock();
2078         data = rcu_dereference(counter->data);
2079         if (!data)
2080                 goto unlock;
2081
2082         userpg = data->user_page;
2083
2084         /*
2085          * Disable preemption so as to not let the corresponding user-space
2086          * spin too long if we get preempted.
2087          */
2088         preempt_disable();
2089         ++userpg->lock;
2090         barrier();
2091         userpg->index = perf_counter_index(counter);
2092         userpg->offset = atomic64_read(&counter->count);
2093         if (counter->state == PERF_COUNTER_STATE_ACTIVE)
2094                 userpg->offset -= atomic64_read(&counter->hw.prev_count);
2095
2096         userpg->time_enabled = counter->total_time_enabled +
2097                         atomic64_read(&counter->child_total_time_enabled);
2098
2099         userpg->time_running = counter->total_time_running +
2100                         atomic64_read(&counter->child_total_time_running);
2101
2102         barrier();
2103         ++userpg->lock;
2104         preempt_enable();
2105 unlock:
2106         rcu_read_unlock();
2107 }
2108
2109 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2110 {
2111         struct perf_counter *counter = vma->vm_file->private_data;
2112         struct perf_mmap_data *data;
2113         int ret = VM_FAULT_SIGBUS;
2114
2115         if (vmf->flags & FAULT_FLAG_MKWRITE) {
2116                 if (vmf->pgoff == 0)
2117                         ret = 0;
2118                 return ret;
2119         }
2120
2121         rcu_read_lock();
2122         data = rcu_dereference(counter->data);
2123         if (!data)
2124                 goto unlock;
2125
2126         if (vmf->pgoff == 0) {
2127                 vmf->page = virt_to_page(data->user_page);
2128         } else {
2129                 int nr = vmf->pgoff - 1;
2130
2131                 if ((unsigned)nr > data->nr_pages)
2132                         goto unlock;
2133
2134                 if (vmf->flags & FAULT_FLAG_WRITE)
2135                         goto unlock;
2136
2137                 vmf->page = virt_to_page(data->data_pages[nr]);
2138         }
2139
2140         get_page(vmf->page);
2141         vmf->page->mapping = vma->vm_file->f_mapping;
2142         vmf->page->index   = vmf->pgoff;
2143
2144         ret = 0;
2145 unlock:
2146         rcu_read_unlock();
2147
2148         return ret;
2149 }
2150
2151 static int perf_mmap_data_alloc(struct perf_counter *counter, int nr_pages)
2152 {
2153         struct perf_mmap_data *data;
2154         unsigned long size;
2155         int i;
2156
2157         WARN_ON(atomic_read(&counter->mmap_count));
2158
2159         size = sizeof(struct perf_mmap_data);
2160         size += nr_pages * sizeof(void *);
2161
2162         data = kzalloc(size, GFP_KERNEL);
2163         if (!data)
2164                 goto fail;
2165
2166         data->user_page = (void *)get_zeroed_page(GFP_KERNEL);
2167         if (!data->user_page)
2168                 goto fail_user_page;
2169
2170         for (i = 0; i < nr_pages; i++) {
2171                 data->data_pages[i] = (void *)get_zeroed_page(GFP_KERNEL);
2172                 if (!data->data_pages[i])
2173                         goto fail_data_pages;
2174         }
2175
2176         data->nr_pages = nr_pages;
2177         atomic_set(&data->lock, -1);
2178
2179         if (counter->attr.watermark) {
2180                 data->watermark = min_t(long, PAGE_SIZE * nr_pages,
2181                                       counter->attr.wakeup_watermark);
2182         }
2183         if (!data->watermark)
2184                 data->watermark = max(PAGE_SIZE, PAGE_SIZE * nr_pages / 4);
2185
2186         rcu_assign_pointer(counter->data, data);
2187
2188         return 0;
2189
2190 fail_data_pages:
2191         for (i--; i >= 0; i--)
2192                 free_page((unsigned long)data->data_pages[i]);
2193
2194         free_page((unsigned long)data->user_page);
2195
2196 fail_user_page:
2197         kfree(data);
2198
2199 fail:
2200         return -ENOMEM;
2201 }
2202
2203 static void perf_mmap_free_page(unsigned long addr)
2204 {
2205         struct page *page = virt_to_page((void *)addr);
2206
2207         page->mapping = NULL;
2208         __free_page(page);
2209 }
2210
2211 static void __perf_mmap_data_free(struct rcu_head *rcu_head)
2212 {
2213         struct perf_mmap_data *data;
2214         int i;
2215
2216         data = container_of(rcu_head, struct perf_mmap_data, rcu_head);
2217
2218         perf_mmap_free_page((unsigned long)data->user_page);
2219         for (i = 0; i < data->nr_pages; i++)
2220                 perf_mmap_free_page((unsigned long)data->data_pages[i]);
2221
2222         kfree(data);
2223 }
2224
2225 static void perf_mmap_data_free(struct perf_counter *counter)
2226 {
2227         struct perf_mmap_data *data = counter->data;
2228
2229         WARN_ON(atomic_read(&counter->mmap_count));
2230
2231         rcu_assign_pointer(counter->data, NULL);
2232         call_rcu(&data->rcu_head, __perf_mmap_data_free);
2233 }
2234
2235 static void perf_mmap_open(struct vm_area_struct *vma)
2236 {
2237         struct perf_counter *counter = vma->vm_file->private_data;
2238
2239         atomic_inc(&counter->mmap_count);
2240 }
2241
2242 static void perf_mmap_close(struct vm_area_struct *vma)
2243 {
2244         struct perf_counter *counter = vma->vm_file->private_data;
2245
2246         WARN_ON_ONCE(counter->ctx->parent_ctx);
2247         if (atomic_dec_and_mutex_lock(&counter->mmap_count, &counter->mmap_mutex)) {
2248                 struct user_struct *user = current_user();
2249
2250                 atomic_long_sub(counter->data->nr_pages + 1, &user->locked_vm);
2251                 vma->vm_mm->locked_vm -= counter->data->nr_locked;
2252                 perf_mmap_data_free(counter);
2253                 mutex_unlock(&counter->mmap_mutex);
2254         }
2255 }
2256
2257 static struct vm_operations_struct perf_mmap_vmops = {
2258         .open           = perf_mmap_open,
2259         .close          = perf_mmap_close,
2260         .fault          = perf_mmap_fault,
2261         .page_mkwrite   = perf_mmap_fault,
2262 };
2263
2264 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
2265 {
2266         struct perf_counter *counter = file->private_data;
2267         unsigned long user_locked, user_lock_limit;
2268         struct user_struct *user = current_user();
2269         unsigned long locked, lock_limit;
2270         unsigned long vma_size;
2271         unsigned long nr_pages;
2272         long user_extra, extra;
2273         int ret = 0;
2274
2275         if (!(vma->vm_flags & VM_SHARED))
2276                 return -EINVAL;
2277
2278         vma_size = vma->vm_end - vma->vm_start;
2279         nr_pages = (vma_size / PAGE_SIZE) - 1;
2280
2281         /*
2282          * If we have data pages ensure they're a power-of-two number, so we
2283          * can do bitmasks instead of modulo.
2284          */
2285         if (nr_pages != 0 && !is_power_of_2(nr_pages))
2286                 return -EINVAL;
2287
2288         if (vma_size != PAGE_SIZE * (1 + nr_pages))
2289                 return -EINVAL;
2290
2291         if (vma->vm_pgoff != 0)
2292                 return -EINVAL;
2293
2294         WARN_ON_ONCE(counter->ctx->parent_ctx);
2295         mutex_lock(&counter->mmap_mutex);
2296         if (counter->output) {
2297                 ret = -EINVAL;
2298                 goto unlock;
2299         }
2300
2301         if (atomic_inc_not_zero(&counter->mmap_count)) {
2302                 if (nr_pages != counter->data->nr_pages)
2303                         ret = -EINVAL;
2304                 goto unlock;
2305         }
2306
2307         user_extra = nr_pages + 1;
2308         user_lock_limit = sysctl_perf_counter_mlock >> (PAGE_SHIFT - 10);
2309
2310         /*
2311          * Increase the limit linearly with more CPUs:
2312          */
2313         user_lock_limit *= num_online_cpus();
2314
2315         user_locked = atomic_long_read(&user->locked_vm) + user_extra;
2316
2317         extra = 0;
2318         if (user_locked > user_lock_limit)
2319                 extra = user_locked - user_lock_limit;
2320
2321         lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
2322         lock_limit >>= PAGE_SHIFT;
2323         locked = vma->vm_mm->locked_vm + extra;
2324
2325         if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
2326                 !capable(CAP_IPC_LOCK)) {
2327                 ret = -EPERM;
2328                 goto unlock;
2329         }
2330
2331         WARN_ON(counter->data);
2332         ret = perf_mmap_data_alloc(counter, nr_pages);
2333         if (ret)
2334                 goto unlock;
2335
2336         atomic_set(&counter->mmap_count, 1);
2337         atomic_long_add(user_extra, &user->locked_vm);
2338         vma->vm_mm->locked_vm += extra;
2339         counter->data->nr_locked = extra;
2340         if (vma->vm_flags & VM_WRITE)
2341                 counter->data->writable = 1;
2342
2343 unlock:
2344         mutex_unlock(&counter->mmap_mutex);
2345
2346         vma->vm_flags |= VM_RESERVED;
2347         vma->vm_ops = &perf_mmap_vmops;
2348
2349         return ret;
2350 }
2351
2352 static int perf_fasync(int fd, struct file *filp, int on)
2353 {
2354         struct inode *inode = filp->f_path.dentry->d_inode;
2355         struct perf_counter *counter = filp->private_data;
2356         int retval;
2357
2358         mutex_lock(&inode->i_mutex);
2359         retval = fasync_helper(fd, filp, on, &counter->fasync);
2360         mutex_unlock(&inode->i_mutex);
2361
2362         if (retval < 0)
2363                 return retval;
2364
2365         return 0;
2366 }
2367
2368 static const struct file_operations perf_fops = {
2369         .release                = perf_release,
2370         .read                   = perf_read,
2371         .poll                   = perf_poll,
2372         .unlocked_ioctl         = perf_ioctl,
2373         .compat_ioctl           = perf_ioctl,
2374         .mmap                   = perf_mmap,
2375         .fasync                 = perf_fasync,
2376 };
2377
2378 /*
2379  * Perf counter wakeup
2380  *
2381  * If there's data, ensure we set the poll() state and publish everything
2382  * to user-space before waking everybody up.
2383  */
2384
2385 void perf_counter_wakeup(struct perf_counter *counter)
2386 {
2387         wake_up_all(&counter->waitq);
2388
2389         if (counter->pending_kill) {
2390                 kill_fasync(&counter->fasync, SIGIO, counter->pending_kill);
2391                 counter->pending_kill = 0;
2392         }
2393 }
2394
2395 /*
2396  * Pending wakeups
2397  *
2398  * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
2399  *
2400  * The NMI bit means we cannot possibly take locks. Therefore, maintain a
2401  * single linked list and use cmpxchg() to add entries lockless.
2402  */
2403
2404 static void perf_pending_counter(struct perf_pending_entry *entry)
2405 {
2406         struct perf_counter *counter = container_of(entry,
2407                         struct perf_counter, pending);
2408
2409         if (counter->pending_disable) {
2410                 counter->pending_disable = 0;
2411                 __perf_counter_disable(counter);
2412         }
2413
2414         if (counter->pending_wakeup) {
2415                 counter->pending_wakeup = 0;
2416                 perf_counter_wakeup(counter);
2417         }
2418 }
2419
2420 #define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
2421
2422 static DEFINE_PER_CPU(struct perf_pending_entry *, perf_pending_head) = {
2423         PENDING_TAIL,
2424 };
2425
2426 static void perf_pending_queue(struct perf_pending_entry *entry,
2427                                void (*func)(struct perf_pending_entry *))
2428 {
2429         struct perf_pending_entry **head;
2430
2431         if (cmpxchg(&entry->next, NULL, PENDING_TAIL) != NULL)
2432                 return;
2433
2434         entry->func = func;
2435
2436         head = &get_cpu_var(perf_pending_head);
2437
2438         do {
2439                 entry->next = *head;
2440         } while (cmpxchg(head, entry->next, entry) != entry->next);
2441
2442         set_perf_counter_pending();
2443
2444         put_cpu_var(perf_pending_head);
2445 }
2446
2447 static int __perf_pending_run(void)
2448 {
2449         struct perf_pending_entry *list;
2450         int nr = 0;
2451
2452         list = xchg(&__get_cpu_var(perf_pending_head), PENDING_TAIL);
2453         while (list != PENDING_TAIL) {
2454                 void (*func)(struct perf_pending_entry *);
2455                 struct perf_pending_entry *entry = list;
2456
2457                 list = list->next;
2458
2459                 func = entry->func;
2460                 entry->next = NULL;
2461                 /*
2462                  * Ensure we observe the unqueue before we issue the wakeup,
2463                  * so that we won't be waiting forever.
2464                  * -- see perf_not_pending().
2465                  */
2466                 smp_wmb();
2467
2468                 func(entry);
2469                 nr++;
2470         }
2471
2472         return nr;
2473 }
2474
2475 static inline int perf_not_pending(struct perf_counter *counter)
2476 {
2477         /*
2478          * If we flush on whatever cpu we run, there is a chance we don't
2479          * need to wait.
2480          */
2481         get_cpu();
2482         __perf_pending_run();
2483         put_cpu();
2484
2485         /*
2486          * Ensure we see the proper queue state before going to sleep
2487          * so that we do not miss the wakeup. -- see perf_pending_handle()
2488          */
2489         smp_rmb();
2490         return counter->pending.next == NULL;
2491 }
2492
2493 static void perf_pending_sync(struct perf_counter *counter)
2494 {
2495         wait_event(counter->waitq, perf_not_pending(counter));
2496 }
2497
2498 void perf_counter_do_pending(void)
2499 {
2500         __perf_pending_run();
2501 }
2502
2503 /*
2504  * Callchain support -- arch specific
2505  */
2506
2507 __weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
2508 {
2509         return NULL;
2510 }
2511
2512 /*
2513  * Output
2514  */
2515 static bool perf_output_space(struct perf_mmap_data *data, unsigned long tail,
2516                               unsigned long offset, unsigned long head)
2517 {
2518         unsigned long mask;
2519
2520         if (!data->writable)
2521                 return true;
2522
2523         mask = (data->nr_pages << PAGE_SHIFT) - 1;
2524
2525         offset = (offset - tail) & mask;
2526         head   = (head   - tail) & mask;
2527
2528         if ((int)(head - offset) < 0)
2529                 return false;
2530
2531         return true;
2532 }
2533
2534 static void perf_output_wakeup(struct perf_output_handle *handle)
2535 {
2536         atomic_set(&handle->data->poll, POLL_IN);
2537
2538         if (handle->nmi) {
2539                 handle->counter->pending_wakeup = 1;
2540                 perf_pending_queue(&handle->counter->pending,
2541                                    perf_pending_counter);
2542         } else
2543                 perf_counter_wakeup(handle->counter);
2544 }
2545
2546 /*
2547  * Curious locking construct.
2548  *
2549  * We need to ensure a later event doesn't publish a head when a former
2550  * event isn't done writing. However since we need to deal with NMIs we
2551  * cannot fully serialize things.
2552  *
2553  * What we do is serialize between CPUs so we only have to deal with NMI
2554  * nesting on a single CPU.
2555  *
2556  * We only publish the head (and generate a wakeup) when the outer-most
2557  * event completes.
2558  */
2559 static void perf_output_lock(struct perf_output_handle *handle)
2560 {
2561         struct perf_mmap_data *data = handle->data;
2562         int cpu;
2563
2564         handle->locked = 0;
2565
2566         local_irq_save(handle->flags);
2567         cpu = smp_processor_id();
2568
2569         if (in_nmi() && atomic_read(&data->lock) == cpu)
2570                 return;
2571
2572         while (atomic_cmpxchg(&data->lock, -1, cpu) != -1)
2573                 cpu_relax();
2574
2575         handle->locked = 1;
2576 }
2577
2578 static void perf_output_unlock(struct perf_output_handle *handle)
2579 {
2580         struct perf_mmap_data *data = handle->data;
2581         unsigned long head;
2582         int cpu;
2583
2584         data->done_head = data->head;
2585
2586         if (!handle->locked)
2587                 goto out;
2588
2589 again:
2590         /*
2591          * The xchg implies a full barrier that ensures all writes are done
2592          * before we publish the new head, matched by a rmb() in userspace when
2593          * reading this position.
2594          */
2595         while ((head = atomic_long_xchg(&data->done_head, 0)))
2596                 data->user_page->data_head = head;
2597
2598         /*
2599          * NMI can happen here, which means we can miss a done_head update.
2600          */
2601
2602         cpu = atomic_xchg(&data->lock, -1);
2603         WARN_ON_ONCE(cpu != smp_processor_id());
2604
2605         /*
2606          * Therefore we have to validate we did not indeed do so.
2607          */
2608         if (unlikely(atomic_long_read(&data->done_head))) {
2609                 /*
2610                  * Since we had it locked, we can lock it again.
2611                  */
2612                 while (atomic_cmpxchg(&data->lock, -1, cpu) != -1)
2613                         cpu_relax();
2614
2615                 goto again;
2616         }
2617
2618         if (atomic_xchg(&data->wakeup, 0))
2619                 perf_output_wakeup(handle);
2620 out:
2621         local_irq_restore(handle->flags);
2622 }
2623
2624 void perf_output_copy(struct perf_output_handle *handle,
2625                       const void *buf, unsigned int len)
2626 {
2627         unsigned int pages_mask;
2628         unsigned int offset;
2629         unsigned int size;
2630         void **pages;
2631
2632         offset          = handle->offset;
2633         pages_mask      = handle->data->nr_pages - 1;
2634         pages           = handle->data->data_pages;
2635
2636         do {
2637                 unsigned int page_offset;
2638                 int nr;
2639
2640                 nr          = (offset >> PAGE_SHIFT) & pages_mask;
2641                 page_offset = offset & (PAGE_SIZE - 1);
2642                 size        = min_t(unsigned int, PAGE_SIZE - page_offset, len);
2643
2644                 memcpy(pages[nr] + page_offset, buf, size);
2645
2646                 len         -= size;
2647                 buf         += size;
2648                 offset      += size;
2649         } while (len);
2650
2651         handle->offset = offset;
2652
2653         /*
2654          * Check we didn't copy past our reservation window, taking the
2655          * possible unsigned int wrap into account.
2656          */
2657         WARN_ON_ONCE(((long)(handle->head - handle->offset)) < 0);
2658 }
2659
2660 int perf_output_begin(struct perf_output_handle *handle,
2661                       struct perf_counter *counter, unsigned int size,
2662                       int nmi, int sample)
2663 {
2664         struct perf_counter *output_counter;
2665         struct perf_mmap_data *data;
2666         unsigned long tail, offset, head;
2667         int have_lost;
2668         struct {
2669                 struct perf_event_header header;
2670                 u64                      id;
2671                 u64                      lost;
2672         } lost_event;
2673
2674         rcu_read_lock();
2675         /*
2676          * For inherited counters we send all the output towards the parent.
2677          */
2678         if (counter->parent)
2679                 counter = counter->parent;
2680
2681         output_counter = rcu_dereference(counter->output);
2682         if (output_counter)
2683                 counter = output_counter;
2684
2685         data = rcu_dereference(counter->data);
2686         if (!data)
2687                 goto out;
2688
2689         handle->data    = data;
2690         handle->counter = counter;
2691         handle->nmi     = nmi;
2692         handle->sample  = sample;
2693
2694         if (!data->nr_pages)
2695                 goto fail;
2696
2697         have_lost = atomic_read(&data->lost);
2698         if (have_lost)
2699                 size += sizeof(lost_event);
2700
2701         perf_output_lock(handle);
2702
2703         do {
2704                 /*
2705                  * Userspace could choose to issue a mb() before updating the
2706                  * tail pointer. So that all reads will be completed before the
2707                  * write is issued.
2708                  */
2709                 tail = ACCESS_ONCE(data->user_page->data_tail);
2710                 smp_rmb();
2711                 offset = head = atomic_long_read(&data->head);
2712                 head += size;
2713                 if (unlikely(!perf_output_space(data, tail, offset, head)))
2714                         goto fail;
2715         } while (atomic_long_cmpxchg(&data->head, offset, head) != offset);
2716
2717         handle->offset  = offset;
2718         handle->head    = head;
2719
2720         if (head - tail > data->watermark)
2721                 atomic_set(&data->wakeup, 1);
2722
2723         if (have_lost) {
2724                 lost_event.header.type = PERF_EVENT_LOST;
2725                 lost_event.header.misc = 0;
2726                 lost_event.header.size = sizeof(lost_event);
2727                 lost_event.id          = counter->id;
2728                 lost_event.lost        = atomic_xchg(&data->lost, 0);
2729
2730                 perf_output_put(handle, lost_event);
2731         }
2732
2733         return 0;
2734
2735 fail:
2736         atomic_inc(&data->lost);
2737         perf_output_unlock(handle);
2738 out:
2739         rcu_read_unlock();
2740
2741         return -ENOSPC;
2742 }
2743
2744 void perf_output_end(struct perf_output_handle *handle)
2745 {
2746         struct perf_counter *counter = handle->counter;
2747         struct perf_mmap_data *data = handle->data;
2748
2749         int wakeup_events = counter->attr.wakeup_events;
2750
2751         if (handle->sample && wakeup_events) {
2752                 int events = atomic_inc_return(&data->events);
2753                 if (events >= wakeup_events) {
2754                         atomic_sub(wakeup_events, &data->events);
2755                         atomic_set(&data->wakeup, 1);
2756                 }
2757         }
2758
2759         perf_output_unlock(handle);
2760         rcu_read_unlock();
2761 }
2762
2763 static u32 perf_counter_pid(struct perf_counter *counter, struct task_struct *p)
2764 {
2765         /*
2766          * only top level counters have the pid namespace they were created in
2767          */
2768         if (counter->parent)
2769                 counter = counter->parent;
2770
2771         return task_tgid_nr_ns(p, counter->ns);
2772 }
2773
2774 static u32 perf_counter_tid(struct perf_counter *counter, struct task_struct *p)
2775 {
2776         /*
2777          * only top level counters have the pid namespace they were created in
2778          */
2779         if (counter->parent)
2780                 counter = counter->parent;
2781
2782         return task_pid_nr_ns(p, counter->ns);
2783 }
2784
2785 static void perf_output_read_one(struct perf_output_handle *handle,
2786                                  struct perf_counter *counter)
2787 {
2788         u64 read_format = counter->attr.read_format;
2789         u64 values[4];
2790         int n = 0;
2791
2792         values[n++] = atomic64_read(&counter->count);
2793         if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
2794                 values[n++] = counter->total_time_enabled +
2795                         atomic64_read(&counter->child_total_time_enabled);
2796         }
2797         if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
2798                 values[n++] = counter->total_time_running +
2799                         atomic64_read(&counter->child_total_time_running);
2800         }
2801         if (read_format & PERF_FORMAT_ID)
2802                 values[n++] = primary_counter_id(counter);
2803
2804         perf_output_copy(handle, values, n * sizeof(u64));
2805 }
2806
2807 /*
2808  * XXX PERF_FORMAT_GROUP vs inherited counters seems difficult.
2809  */
2810 static void perf_output_read_group(struct perf_output_handle *handle,
2811                             struct perf_counter *counter)
2812 {
2813         struct perf_counter *leader = counter->group_leader, *sub;
2814         u64 read_format = counter->attr.read_format;
2815         u64 values[5];
2816         int n = 0;
2817
2818         values[n++] = 1 + leader->nr_siblings;
2819
2820         if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
2821                 values[n++] = leader->total_time_enabled;
2822
2823         if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
2824                 values[n++] = leader->total_time_running;
2825
2826         if (leader != counter)
2827                 leader->pmu->read(leader);
2828
2829         values[n++] = atomic64_read(&leader->count);
2830         if (read_format & PERF_FORMAT_ID)
2831                 values[n++] = primary_counter_id(leader);
2832
2833         perf_output_copy(handle, values, n * sizeof(u64));
2834
2835         list_for_each_entry(sub, &leader->sibling_list, list_entry) {
2836                 n = 0;
2837
2838                 if (sub != counter)
2839                         sub->pmu->read(sub);
2840
2841                 values[n++] = atomic64_read(&sub->count);
2842                 if (read_format & PERF_FORMAT_ID)
2843                         values[n++] = primary_counter_id(sub);
2844
2845                 perf_output_copy(handle, values, n * sizeof(u64));
2846         }
2847 }
2848
2849 static void perf_output_read(struct perf_output_handle *handle,
2850                              struct perf_counter *counter)
2851 {
2852         if (counter->attr.read_format & PERF_FORMAT_GROUP)
2853                 perf_output_read_group(handle, counter);
2854         else
2855                 perf_output_read_one(handle, counter);
2856 }
2857
2858 void perf_output_sample(struct perf_output_handle *handle,
2859                         struct perf_event_header *header,
2860                         struct perf_sample_data *data,
2861                         struct perf_counter *counter)
2862 {
2863         u64 sample_type = data->type;
2864
2865         perf_output_put(handle, *header);
2866
2867         if (sample_type & PERF_SAMPLE_IP)
2868                 perf_output_put(handle, data->ip);
2869
2870         if (sample_type & PERF_SAMPLE_TID)
2871                 perf_output_put(handle, data->tid_entry);
2872
2873         if (sample_type & PERF_SAMPLE_TIME)
2874                 perf_output_put(handle, data->time);
2875
2876         if (sample_type & PERF_SAMPLE_ADDR)
2877                 perf_output_put(handle, data->addr);
2878
2879         if (sample_type & PERF_SAMPLE_ID)
2880                 perf_output_put(handle, data->id);
2881
2882         if (sample_type & PERF_SAMPLE_STREAM_ID)
2883                 perf_output_put(handle, data->stream_id);
2884
2885         if (sample_type & PERF_SAMPLE_CPU)
2886                 perf_output_put(handle, data->cpu_entry);
2887
2888         if (sample_type & PERF_SAMPLE_PERIOD)
2889                 perf_output_put(handle, data->period);
2890
2891         if (sample_type & PERF_SAMPLE_READ)
2892                 perf_output_read(handle, counter);
2893
2894         if (sample_type & PERF_SAMPLE_CALLCHAIN) {
2895                 if (data->callchain) {
2896                         int size = 1;
2897
2898                         if (data->callchain)
2899                                 size += data->callchain->nr;
2900
2901                         size *= sizeof(u64);
2902
2903                         perf_output_copy(handle, data->callchain, size);
2904                 } else {
2905                         u64 nr = 0;
2906                         perf_output_put(handle, nr);
2907                 }
2908         }
2909
2910         if (sample_type & PERF_SAMPLE_RAW) {
2911                 if (data->raw) {
2912                         perf_output_put(handle, data->raw->size);
2913                         perf_output_copy(handle, data->raw->data,
2914                                          data->raw->size);
2915                 } else {
2916                         struct {
2917                                 u32     size;
2918                                 u32     data;
2919                         } raw = {
2920                                 .size = sizeof(u32),
2921                                 .data = 0,
2922                         };
2923                         perf_output_put(handle, raw);
2924                 }
2925         }
2926 }
2927
2928 void perf_prepare_sample(struct perf_event_header *header,
2929                          struct perf_sample_data *data,
2930                          struct perf_counter *counter,
2931                          struct pt_regs *regs)
2932 {
2933         u64 sample_type = counter->attr.sample_type;
2934
2935         data->type = sample_type;
2936
2937         header->type = PERF_EVENT_SAMPLE;
2938         header->size = sizeof(*header);
2939
2940         header->misc = 0;
2941         header->misc |= perf_misc_flags(regs);
2942
2943         if (sample_type & PERF_SAMPLE_IP) {
2944                 data->ip = perf_instruction_pointer(regs);
2945
2946                 header->size += sizeof(data->ip);
2947         }
2948
2949         if (sample_type & PERF_SAMPLE_TID) {
2950                 /* namespace issues */
2951                 data->tid_entry.pid = perf_counter_pid(counter, current);
2952                 data->tid_entry.tid = perf_counter_tid(counter, current);
2953
2954                 header->size += sizeof(data->tid_entry);
2955         }
2956
2957         if (sample_type & PERF_SAMPLE_TIME) {
2958                 data->time = perf_clock();
2959
2960                 header->size += sizeof(data->time);
2961         }
2962
2963         if (sample_type & PERF_SAMPLE_ADDR)
2964                 header->size += sizeof(data->addr);
2965
2966         if (sample_type & PERF_SAMPLE_ID) {
2967                 data->id = primary_counter_id(counter);
2968
2969                 header->size += sizeof(data->id);
2970         }
2971
2972         if (sample_type & PERF_SAMPLE_STREAM_ID) {
2973                 data->stream_id = counter->id;
2974
2975                 header->size += sizeof(data->stream_id);
2976         }
2977
2978         if (sample_type & PERF_SAMPLE_CPU) {
2979                 data->cpu_entry.cpu             = raw_smp_processor_id();
2980                 data->cpu_entry.reserved        = 0;
2981
2982                 header->size += sizeof(data->cpu_entry);
2983         }
2984
2985         if (sample_type & PERF_SAMPLE_PERIOD)
2986                 header->size += sizeof(data->period);
2987
2988         if (sample_type & PERF_SAMPLE_READ)
2989                 header->size += perf_counter_read_size(counter);
2990
2991         if (sample_type & PERF_SAMPLE_CALLCHAIN) {
2992                 int size = 1;
2993
2994                 data->callchain = perf_callchain(regs);
2995
2996                 if (data->callchain)
2997                         size += data->callchain->nr;
2998
2999                 header->size += size * sizeof(u64);
3000         }
3001
3002         if (sample_type & PERF_SAMPLE_RAW) {
3003                 int size = sizeof(u32);
3004
3005                 if (data->raw)
3006                         size += data->raw->size;
3007                 else
3008                         size += sizeof(u32);
3009
3010                 WARN_ON_ONCE(size & (sizeof(u64)-1));
3011                 header->size += size;
3012         }
3013 }
3014
3015 static void perf_counter_output(struct perf_counter *counter, int nmi,
3016                                 struct perf_sample_data *data,
3017                                 struct pt_regs *regs)
3018 {
3019         struct perf_output_handle handle;
3020         struct perf_event_header header;
3021
3022         perf_prepare_sample(&header, data, counter, regs);
3023
3024         if (perf_output_begin(&handle, counter, header.size, nmi, 1))
3025                 return;
3026
3027         perf_output_sample(&handle, &header, data, counter);
3028
3029         perf_output_end(&handle);
3030 }
3031
3032 /*
3033  * read event
3034  */
3035
3036 struct perf_read_event {
3037         struct perf_event_header        header;
3038
3039         u32                             pid;
3040         u32                             tid;
3041 };
3042
3043 static void
3044 perf_counter_read_event(struct perf_counter *counter,
3045                         struct task_struct *task)
3046 {
3047         struct perf_output_handle handle;
3048         struct perf_read_event event = {
3049                 .header = {
3050                         .type = PERF_EVENT_READ,
3051                         .misc = 0,
3052                         .size = sizeof(event) + perf_counter_read_size(counter),
3053                 },
3054                 .pid = perf_counter_pid(counter, task),
3055                 .tid = perf_counter_tid(counter, task),
3056         };
3057         int ret;
3058
3059         ret = perf_output_begin(&handle, counter, event.header.size, 0, 0);
3060         if (ret)
3061                 return;
3062
3063         perf_output_put(&handle, event);
3064         perf_output_read(&handle, counter);
3065
3066         perf_output_end(&handle);
3067 }
3068
3069 /*
3070  * task tracking -- fork/exit
3071  *
3072  * enabled by: attr.comm | attr.mmap | attr.task
3073  */
3074
3075 struct perf_task_event {
3076         struct task_struct              *task;
3077         struct perf_counter_context     *task_ctx;
3078
3079         struct {
3080                 struct perf_event_header        header;
3081
3082                 u32                             pid;
3083                 u32                             ppid;
3084                 u32                             tid;
3085                 u32                             ptid;
3086                 u64                             time;
3087         } event;
3088 };
3089
3090 static void perf_counter_task_output(struct perf_counter *counter,
3091                                      struct perf_task_event *task_event)
3092 {
3093         struct perf_output_handle handle;
3094         int size;
3095         struct task_struct *task = task_event->task;
3096         int ret;
3097
3098         size  = task_event->event.header.size;
3099         ret = perf_output_begin(&handle, counter, size, 0, 0);
3100
3101         if (ret)
3102                 return;
3103
3104         task_event->event.pid = perf_counter_pid(counter, task);
3105         task_event->event.ppid = perf_counter_pid(counter, current);
3106
3107         task_event->event.tid = perf_counter_tid(counter, task);
3108         task_event->event.ptid = perf_counter_tid(counter, current);
3109
3110         task_event->event.time = perf_clock();
3111
3112         perf_output_put(&handle, task_event->event);
3113
3114         perf_output_end(&handle);
3115 }
3116
3117 static int perf_counter_task_match(struct perf_counter *counter)
3118 {
3119         if (counter->attr.comm || counter->attr.mmap || counter->attr.task)
3120                 return 1;
3121
3122         return 0;
3123 }
3124
3125 static void perf_counter_task_ctx(struct perf_counter_context *ctx,
3126                                   struct perf_task_event *task_event)
3127 {
3128         struct perf_counter *counter;
3129
3130         if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
3131                 return;
3132
3133         rcu_read_lock();
3134         list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
3135                 if (perf_counter_task_match(counter))
3136                         perf_counter_task_output(counter, task_event);
3137         }
3138         rcu_read_unlock();
3139 }
3140
3141 static void perf_counter_task_event(struct perf_task_event *task_event)
3142 {
3143         struct perf_cpu_context *cpuctx;
3144         struct perf_counter_context *ctx = task_event->task_ctx;
3145
3146         cpuctx = &get_cpu_var(perf_cpu_context);
3147         perf_counter_task_ctx(&cpuctx->ctx, task_event);
3148         put_cpu_var(perf_cpu_context);
3149
3150         rcu_read_lock();
3151         if (!ctx)
3152                 ctx = rcu_dereference(task_event->task->perf_counter_ctxp);
3153         if (ctx)
3154                 perf_counter_task_ctx(ctx, task_event);
3155         rcu_read_unlock();
3156 }
3157
3158 static void perf_counter_task(struct task_struct *task,
3159                               struct perf_counter_context *task_ctx,
3160                               int new)
3161 {
3162         struct perf_task_event task_event;
3163
3164         if (!atomic_read(&nr_comm_counters) &&
3165             !atomic_read(&nr_mmap_counters) &&
3166             !atomic_read(&nr_task_counters))
3167                 return;
3168
3169         task_event = (struct perf_task_event){
3170                 .task     = task,
3171                 .task_ctx = task_ctx,
3172                 .event    = {
3173                         .header = {
3174                                 .type = new ? PERF_EVENT_FORK : PERF_EVENT_EXIT,
3175                                 .misc = 0,
3176                                 .size = sizeof(task_event.event),
3177                         },
3178                         /* .pid  */
3179                         /* .ppid */
3180                         /* .tid  */
3181                         /* .ptid */
3182                 },
3183         };
3184
3185         perf_counter_task_event(&task_event);
3186 }
3187
3188 void perf_counter_fork(struct task_struct *task)
3189 {
3190         perf_counter_task(task, NULL, 1);
3191 }
3192
3193 /*
3194  * comm tracking
3195  */
3196
3197 struct perf_comm_event {
3198         struct task_struct      *task;
3199         char                    *comm;
3200         int                     comm_size;
3201
3202         struct {
3203                 struct perf_event_header        header;
3204
3205                 u32                             pid;
3206                 u32                             tid;
3207         } event;
3208 };
3209
3210 static void perf_counter_comm_output(struct perf_counter *counter,
3211                                      struct perf_comm_event *comm_event)
3212 {
3213         struct perf_output_handle handle;
3214         int size = comm_event->event.header.size;
3215         int ret = perf_output_begin(&handle, counter, size, 0, 0);
3216
3217         if (ret)
3218                 return;
3219
3220         comm_event->event.pid = perf_counter_pid(counter, comm_event->task);
3221         comm_event->event.tid = perf_counter_tid(counter, comm_event->task);
3222
3223         perf_output_put(&handle, comm_event->event);
3224         perf_output_copy(&handle, comm_event->comm,
3225                                    comm_event->comm_size);
3226         perf_output_end(&handle);
3227 }
3228
3229 static int perf_counter_comm_match(struct perf_counter *counter)
3230 {
3231         if (counter->attr.comm)
3232                 return 1;
3233
3234         return 0;
3235 }
3236
3237 static void perf_counter_comm_ctx(struct perf_counter_context *ctx,
3238                                   struct perf_comm_event *comm_event)
3239 {
3240         struct perf_counter *counter;
3241
3242         if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
3243                 return;
3244
3245         rcu_read_lock();
3246         list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
3247                 if (perf_counter_comm_match(counter))
3248                         perf_counter_comm_output(counter, comm_event);
3249         }
3250         rcu_read_unlock();
3251 }
3252
3253 static void perf_counter_comm_event(struct perf_comm_event *comm_event)
3254 {
3255         struct perf_cpu_context *cpuctx;
3256         struct perf_counter_context *ctx;
3257         unsigned int size;
3258         char comm[TASK_COMM_LEN];
3259
3260         memset(comm, 0, sizeof(comm));
3261         strncpy(comm, comm_event->task->comm, sizeof(comm));
3262         size = ALIGN(strlen(comm)+1, sizeof(u64));
3263
3264         comm_event->comm = comm;
3265         comm_event->comm_size = size;
3266
3267         comm_event->event.header.size = sizeof(comm_event->event) + size;
3268
3269         cpuctx = &get_cpu_var(perf_cpu_context);
3270         perf_counter_comm_ctx(&cpuctx->ctx, comm_event);
3271         put_cpu_var(perf_cpu_context);
3272
3273         rcu_read_lock();
3274         /*
3275          * doesn't really matter which of the child contexts the
3276          * events ends up in.
3277          */
3278         ctx = rcu_dereference(current->perf_counter_ctxp);
3279         if (ctx)
3280                 perf_counter_comm_ctx(ctx, comm_event);
3281         rcu_read_unlock();
3282 }
3283
3284 void perf_counter_comm(struct task_struct *task)
3285 {
3286         struct perf_comm_event comm_event;
3287
3288         if (task->perf_counter_ctxp)
3289                 perf_counter_enable_on_exec(task);
3290
3291         if (!atomic_read(&nr_comm_counters))
3292                 return;
3293
3294         comm_event = (struct perf_comm_event){
3295                 .task   = task,
3296                 /* .comm      */
3297                 /* .comm_size */
3298                 .event  = {
3299                         .header = {
3300                                 .type = PERF_EVENT_COMM,
3301                                 .misc = 0,
3302                                 /* .size */
3303                         },
3304                         /* .pid */
3305                         /* .tid */
3306                 },
3307         };
3308
3309         perf_counter_comm_event(&comm_event);
3310 }
3311
3312 /*
3313  * mmap tracking
3314  */
3315
3316 struct perf_mmap_event {
3317         struct vm_area_struct   *vma;
3318
3319         const char              *file_name;
3320         int                     file_size;
3321
3322         struct {
3323                 struct perf_event_header        header;
3324
3325                 u32                             pid;
3326                 u32                             tid;
3327                 u64                             start;
3328                 u64                             len;
3329                 u64                             pgoff;
3330         } event;
3331 };
3332
3333 static void perf_counter_mmap_output(struct perf_counter *counter,
3334                                      struct perf_mmap_event *mmap_event)
3335 {
3336         struct perf_output_handle handle;
3337         int size = mmap_event->event.header.size;
3338         int ret = perf_output_begin(&handle, counter, size, 0, 0);
3339
3340         if (ret)
3341                 return;
3342
3343         mmap_event->event.pid = perf_counter_pid(counter, current);
3344         mmap_event->event.tid = perf_counter_tid(counter, current);
3345
3346         perf_output_put(&handle, mmap_event->event);
3347         perf_output_copy(&handle, mmap_event->file_name,
3348                                    mmap_event->file_size);
3349         perf_output_end(&handle);
3350 }
3351
3352 static int perf_counter_mmap_match(struct perf_counter *counter,
3353                                    struct perf_mmap_event *mmap_event)
3354 {
3355         if (counter->attr.mmap)
3356                 return 1;
3357
3358         return 0;
3359 }
3360
3361 static void perf_counter_mmap_ctx(struct perf_counter_context *ctx,
3362                                   struct perf_mmap_event *mmap_event)
3363 {
3364         struct perf_counter *counter;
3365
3366         if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
3367                 return;
3368
3369         rcu_read_lock();
3370         list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
3371                 if (perf_counter_mmap_match(counter, mmap_event))
3372                         perf_counter_mmap_output(counter, mmap_event);
3373         }
3374         rcu_read_unlock();
3375 }
3376
3377 static void perf_counter_mmap_event(struct perf_mmap_event *mmap_event)
3378 {
3379         struct perf_cpu_context *cpuctx;
3380         struct perf_counter_context *ctx;
3381         struct vm_area_struct *vma = mmap_event->vma;
3382         struct file *file = vma->vm_file;
3383         unsigned int size;
3384         char tmp[16];
3385         char *buf = NULL;
3386         const char *name;
3387
3388         memset(tmp, 0, sizeof(tmp));
3389
3390         if (file) {
3391                 /*
3392                  * d_path works from the end of the buffer backwards, so we
3393                  * need to add enough zero bytes after the string to handle
3394                  * the 64bit alignment we do later.
3395                  */
3396                 buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
3397                 if (!buf) {
3398                         name = strncpy(tmp, "//enomem", sizeof(tmp));
3399                         goto got_name;
3400                 }
3401                 name = d_path(&file->f_path, buf, PATH_MAX);
3402                 if (IS_ERR(name)) {
3403                         name = strncpy(tmp, "//toolong", sizeof(tmp));
3404                         goto got_name;
3405                 }
3406         } else {
3407                 if (arch_vma_name(mmap_event->vma)) {
3408                         name = strncpy(tmp, arch_vma_name(mmap_event->vma),
3409                                        sizeof(tmp));
3410                         goto got_name;
3411                 }
3412
3413                 if (!vma->vm_mm) {
3414                         name = strncpy(tmp, "[vdso]", sizeof(tmp));
3415                         goto got_name;
3416                 }
3417
3418                 name = strncpy(tmp, "//anon", sizeof(tmp));
3419                 goto got_name;
3420         }
3421
3422 got_name:
3423         size = ALIGN(strlen(name)+1, sizeof(u64));
3424
3425         mmap_event->file_name = name;
3426         mmap_event->file_size = size;
3427
3428         mmap_event->event.header.size = sizeof(mmap_event->event) + size;
3429
3430         cpuctx = &get_cpu_var(perf_cpu_context);
3431         perf_counter_mmap_ctx(&cpuctx->ctx, mmap_event);
3432         put_cpu_var(perf_cpu_context);
3433
3434         rcu_read_lock();
3435         /*
3436          * doesn't really matter which of the child contexts the
3437          * events ends up in.
3438          */
3439         ctx = rcu_dereference(current->perf_counter_ctxp);
3440         if (ctx)
3441                 perf_counter_mmap_ctx(ctx, mmap_event);
3442         rcu_read_unlock();
3443
3444         kfree(buf);
3445 }
3446
3447 void __perf_counter_mmap(struct vm_area_struct *vma)
3448 {
3449         struct perf_mmap_event mmap_event;
3450
3451         if (!atomic_read(&nr_mmap_counters))
3452                 return;
3453
3454         mmap_event = (struct perf_mmap_event){
3455                 .vma    = vma,
3456                 /* .file_name */
3457                 /* .file_size */
3458                 .event  = {
3459                         .header = {
3460                                 .type = PERF_EVENT_MMAP,
3461                                 .misc = 0,
3462                                 /* .size */
3463                         },
3464                         /* .pid */
3465                         /* .tid */
3466                         .start  = vma->vm_start,
3467                         .len    = vma->vm_end - vma->vm_start,
3468                         .pgoff  = vma->vm_pgoff,
3469                 },
3470         };
3471
3472         perf_counter_mmap_event(&mmap_event);
3473 }
3474
3475 /*
3476  * IRQ throttle logging
3477  */
3478
3479 static void perf_log_throttle(struct perf_counter *counter, int enable)
3480 {
3481         struct perf_output_handle handle;
3482         int ret;
3483
3484         struct {
3485                 struct perf_event_header        header;
3486                 u64                             time;
3487                 u64                             id;
3488                 u64                             stream_id;
3489         } throttle_event = {
3490                 .header = {
3491                         .type = PERF_EVENT_THROTTLE,
3492                         .misc = 0,
3493                         .size = sizeof(throttle_event),
3494                 },
3495                 .time           = perf_clock(),
3496                 .id             = primary_counter_id(counter),
3497                 .stream_id      = counter->id,
3498         };
3499
3500         if (enable)
3501                 throttle_event.header.type = PERF_EVENT_UNTHROTTLE;
3502
3503         ret = perf_output_begin(&handle, counter, sizeof(throttle_event), 1, 0);
3504         if (ret)
3505                 return;
3506
3507         perf_output_put(&handle, throttle_event);
3508         perf_output_end(&handle);
3509 }
3510
3511 /*
3512  * Generic counter overflow handling, sampling.
3513  */
3514
3515 static int __perf_counter_overflow(struct perf_counter *counter, int nmi,
3516                                    int throttle, struct perf_sample_data *data,
3517                                    struct pt_regs *regs)
3518 {
3519         int events = atomic_read(&counter->event_limit);
3520         struct hw_perf_counter *hwc = &counter->hw;
3521         int ret = 0;
3522
3523         throttle = (throttle && counter->pmu->unthrottle != NULL);
3524
3525         if (!throttle) {
3526                 hwc->interrupts++;
3527         } else {
3528                 if (hwc->interrupts != MAX_INTERRUPTS) {
3529                         hwc->interrupts++;
3530                         if (HZ * hwc->interrupts >
3531                                         (u64)sysctl_perf_counter_sample_rate) {
3532                                 hwc->interrupts = MAX_INTERRUPTS;
3533                                 perf_log_throttle(counter, 0);
3534                                 ret = 1;
3535                         }
3536                 } else {
3537                         /*
3538                          * Keep re-disabling counters even though on the previous
3539                          * pass we disabled it - just in case we raced with a
3540                          * sched-in and the counter got enabled again:
3541                          */
3542                         ret = 1;
3543                 }
3544         }
3545
3546         if (counter->attr.freq) {
3547                 u64 now = perf_clock();
3548                 s64 delta = now - hwc->freq_stamp;
3549
3550                 hwc->freq_stamp = now;
3551
3552                 if (delta > 0 && delta < TICK_NSEC)
3553                         perf_adjust_period(counter, NSEC_PER_SEC / (int)delta);
3554         }
3555
3556         /*
3557          * XXX event_limit might not quite work as expected on inherited
3558          * counters
3559          */
3560
3561         counter->pending_kill = POLL_IN;
3562         if (events && atomic_dec_and_test(&counter->event_limit)) {
3563                 ret = 1;
3564                 counter->pending_kill = POLL_HUP;
3565                 if (nmi) {
3566                         counter->pending_disable = 1;
3567                         perf_pending_queue(&counter->pending,
3568                                            perf_pending_counter);
3569                 } else
3570                         perf_counter_disable(counter);
3571         }
3572
3573         perf_counter_output(counter, nmi, data, regs);
3574         return ret;
3575 }
3576
3577 int perf_counter_overflow(struct perf_counter *counter, int nmi,
3578                           struct perf_sample_data *data,
3579                           struct pt_regs *regs)
3580 {
3581         return __perf_counter_overflow(counter, nmi, 1, data, regs);
3582 }
3583
3584 /*
3585  * Generic software counter infrastructure
3586  */
3587
3588 /*
3589  * We directly increment counter->count and keep a second value in
3590  * counter->hw.period_left to count intervals. This period counter
3591  * is kept in the range [-sample_period, 0] so that we can use the
3592  * sign as trigger.
3593  */
3594
3595 static u64 perf_swcounter_set_period(struct perf_counter *counter)
3596 {
3597         struct hw_perf_counter *hwc = &counter->hw;
3598         u64 period = hwc->last_period;
3599         u64 nr, offset;
3600         s64 old, val;
3601
3602         hwc->last_period = hwc->sample_period;
3603
3604 again:
3605         old = val = atomic64_read(&hwc->period_left);
3606         if (val < 0)
3607                 return 0;
3608
3609         nr = div64_u64(period + val, period);
3610         offset = nr * period;
3611         val -= offset;
3612         if (atomic64_cmpxchg(&hwc->period_left, old, val) != old)
3613                 goto again;
3614
3615         return nr;
3616 }
3617
3618 static void perf_swcounter_overflow(struct perf_counter *counter,
3619                                     int nmi, struct perf_sample_data *data,
3620                                     struct pt_regs *regs)
3621 {
3622         struct hw_perf_counter *hwc = &counter->hw;
3623         int throttle = 0;
3624         u64 overflow;
3625
3626         data->period = counter->hw.last_period;
3627         overflow = perf_swcounter_set_period(counter);
3628
3629         if (hwc->interrupts == MAX_INTERRUPTS)
3630                 return;
3631
3632         for (; overflow; overflow--) {
3633                 if (__perf_counter_overflow(counter, nmi, throttle,
3634                                             data, regs)) {
3635                         /*
3636                          * We inhibit the overflow from happening when
3637                          * hwc->interrupts == MAX_INTERRUPTS.
3638                          */
3639                         break;
3640                 }
3641                 throttle = 1;
3642         }
3643 }
3644
3645 static void perf_swcounter_unthrottle(struct perf_counter *counter)
3646 {
3647         /*
3648          * Nothing to do, we already reset hwc->interrupts.
3649          */
3650 }
3651
3652 static void perf_swcounter_add(struct perf_counter *counter, u64 nr,
3653                                int nmi, struct perf_sample_data *data,
3654                                struct pt_regs *regs)
3655 {
3656         struct hw_perf_counter *hwc = &counter->hw;
3657
3658         atomic64_add(nr, &counter->count);
3659
3660         if (!hwc->sample_period)
3661                 return;
3662
3663         if (!regs)
3664                 return;
3665
3666         if (!atomic64_add_negative(nr, &hwc->period_left))
3667                 perf_swcounter_overflow(counter, nmi, data, regs);
3668 }
3669
3670 static int perf_swcounter_is_counting(struct perf_counter *counter)
3671 {
3672         /*
3673          * The counter is active, we're good!
3674          */
3675         if (counter->state == PERF_COUNTER_STATE_ACTIVE)
3676                 return 1;
3677
3678         /*
3679          * The counter is off/error, not counting.
3680          */
3681         if (counter->state != PERF_COUNTER_STATE_INACTIVE)
3682                 return 0;
3683
3684         /*
3685          * The counter is inactive, if the context is active
3686          * we're part of a group that didn't make it on the 'pmu',
3687          * not counting.
3688          */
3689         if (counter->ctx->is_active)
3690                 return 0;
3691
3692         /*
3693          * We're inactive and the context is too, this means the
3694          * task is scheduled out, we're counting events that happen
3695          * to us, like migration events.
3696          */
3697         return 1;
3698 }
3699
3700 static int perf_swcounter_match(struct perf_counter *counter,
3701                                 enum perf_type_id type,
3702                                 u32 event, struct pt_regs *regs)
3703 {
3704         if (!perf_swcounter_is_counting(counter))
3705                 return 0;
3706
3707         if (counter->attr.type != type)
3708                 return 0;
3709         if (counter->attr.config != event)
3710                 return 0;
3711
3712         if (regs) {
3713                 if (counter->attr.exclude_user && user_mode(regs))
3714                         return 0;
3715
3716                 if (counter->attr.exclude_kernel && !user_mode(regs))
3717                         return 0;
3718         }
3719
3720         return 1;
3721 }
3722
3723 static void perf_swcounter_ctx_event(struct perf_counter_context *ctx,
3724                                      enum perf_type_id type,
3725                                      u32 event, u64 nr, int nmi,
3726                                      struct perf_sample_data *data,
3727                                      struct pt_regs *regs)
3728 {
3729         struct perf_counter *counter;
3730
3731         if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
3732                 return;
3733
3734         rcu_read_lock();
3735         list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
3736                 if (perf_swcounter_match(counter, type, event, regs))
3737                         perf_swcounter_add(counter, nr, nmi, data, regs);
3738         }
3739         rcu_read_unlock();
3740 }
3741
3742 static int *perf_swcounter_recursion_context(struct perf_cpu_context *cpuctx)
3743 {
3744         if (in_nmi())
3745                 return &cpuctx->recursion[3];
3746
3747         if (in_irq())
3748                 return &cpuctx->recursion[2];
3749
3750         if (in_softirq())
3751                 return &cpuctx->recursion[1];
3752
3753         return &cpuctx->recursion[0];
3754 }
3755
3756 static void do_perf_swcounter_event(enum perf_type_id type, u32 event,
3757                                     u64 nr, int nmi,
3758                                     struct perf_sample_data *data,
3759                                     struct pt_regs *regs)
3760 {
3761         struct perf_cpu_context *cpuctx = &get_cpu_var(perf_cpu_context);
3762         int *recursion = perf_swcounter_recursion_context(cpuctx);
3763         struct perf_counter_context *ctx;
3764
3765         if (*recursion)
3766                 goto out;
3767
3768         (*recursion)++;
3769         barrier();
3770
3771         perf_swcounter_ctx_event(&cpuctx->ctx, type, event,
3772                                  nr, nmi, data, regs);
3773         rcu_read_lock();
3774         /*
3775          * doesn't really matter which of the child contexts the
3776          * events ends up in.
3777          */
3778         ctx = rcu_dereference(current->perf_counter_ctxp);
3779         if (ctx)
3780                 perf_swcounter_ctx_event(ctx, type, event, nr, nmi, data, regs);
3781         rcu_read_unlock();
3782
3783         barrier();
3784         (*recursion)--;
3785
3786 out:
3787         put_cpu_var(perf_cpu_context);
3788 }
3789
3790 void __perf_swcounter_event(u32 event, u64 nr, int nmi,
3791                             struct pt_regs *regs, u64 addr)
3792 {
3793         struct perf_sample_data data = {
3794                 .addr = addr,
3795         };
3796
3797         do_perf_swcounter_event(PERF_TYPE_SOFTWARE, event, nr, nmi,
3798                                 &data, regs);
3799 }
3800
3801 static void perf_swcounter_read(struct perf_counter *counter)
3802 {
3803 }
3804
3805 static int perf_swcounter_enable(struct perf_counter *counter)
3806 {
3807         struct hw_perf_counter *hwc = &counter->hw;
3808
3809         if (hwc->sample_period) {
3810                 hwc->last_period = hwc->sample_period;
3811                 perf_swcounter_set_period(counter);
3812         }
3813         return 0;
3814 }
3815
3816 static void perf_swcounter_disable(struct perf_counter *counter)
3817 {
3818 }
3819
3820 static const struct pmu perf_ops_generic = {
3821         .enable         = perf_swcounter_enable,
3822         .disable        = perf_swcounter_disable,
3823         .read           = perf_swcounter_read,
3824         .unthrottle     = perf_swcounter_unthrottle,
3825 };
3826
3827 /*
3828  * hrtimer based swcounter callback
3829  */
3830
3831 static enum hrtimer_restart perf_swcounter_hrtimer(struct hrtimer *hrtimer)
3832 {
3833         enum hrtimer_restart ret = HRTIMER_RESTART;
3834         struct perf_sample_data data;
3835         struct pt_regs *regs;
3836         struct perf_counter *counter;
3837         u64 period;
3838
3839         counter = container_of(hrtimer, struct perf_counter, hw.hrtimer);
3840         counter->pmu->read(counter);
3841
3842         data.addr = 0;
3843         regs = get_irq_regs();
3844         /*
3845          * In case we exclude kernel IPs or are somehow not in interrupt
3846          * context, provide the next best thing, the user IP.
3847          */
3848         if ((counter->attr.exclude_kernel || !regs) &&
3849                         !counter->attr.exclude_user)
3850                 regs = task_pt_regs(current);
3851
3852         if (regs) {
3853                 if (perf_counter_overflow(counter, 0, &data, regs))
3854                         ret = HRTIMER_NORESTART;
3855         }
3856
3857         period = max_t(u64, 10000, counter->hw.sample_period);
3858         hrtimer_forward_now(hrtimer, ns_to_ktime(period));
3859
3860         return ret;
3861 }
3862
3863 /*
3864  * Software counter: cpu wall time clock
3865  */
3866
3867 static void cpu_clock_perf_counter_update(struct perf_counter *counter)
3868 {
3869         int cpu = raw_smp_processor_id();
3870         s64 prev;
3871         u64 now;
3872
3873         now = cpu_clock(cpu);
3874         prev = atomic64_read(&counter->hw.prev_count);
3875         atomic64_set(&counter->hw.prev_count, now);
3876         atomic64_add(now - prev, &counter->count);
3877 }
3878
3879 static int cpu_clock_perf_counter_enable(struct perf_counter *counter)
3880 {
3881         struct hw_perf_counter *hwc = &counter->hw;
3882         int cpu = raw_smp_processor_id();
3883
3884         atomic64_set(&hwc->prev_count, cpu_clock(cpu));
3885         hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
3886         hwc->hrtimer.function = perf_swcounter_hrtimer;
3887         if (hwc->sample_period) {
3888                 u64 period = max_t(u64, 10000, hwc->sample_period);
3889                 __hrtimer_start_range_ns(&hwc->hrtimer,
3890                                 ns_to_ktime(period), 0,
3891                                 HRTIMER_MODE_REL, 0);
3892         }
3893
3894         return 0;
3895 }
3896
3897 static void cpu_clock_perf_counter_disable(struct perf_counter *counter)
3898 {
3899         if (counter->hw.sample_period)
3900                 hrtimer_cancel(&counter->hw.hrtimer);
3901         cpu_clock_perf_counter_update(counter);
3902 }
3903
3904 static void cpu_clock_perf_counter_read(struct perf_counter *counter)
3905 {
3906         cpu_clock_perf_counter_update(counter);
3907 }
3908
3909 static const struct pmu perf_ops_cpu_clock = {
3910         .enable         = cpu_clock_perf_counter_enable,
3911         .disable        = cpu_clock_perf_counter_disable,
3912         .read           = cpu_clock_perf_counter_read,
3913 };
3914
3915 /*
3916  * Software counter: task time clock
3917  */
3918
3919 static void task_clock_perf_counter_update(struct perf_counter *counter, u64 now)
3920 {
3921         u64 prev;
3922         s64 delta;
3923
3924         prev = atomic64_xchg(&counter->hw.prev_count, now);
3925         delta = now - prev;
3926         atomic64_add(delta, &counter->count);
3927 }
3928
3929 static int task_clock_perf_counter_enable(struct perf_counter *counter)
3930 {
3931         struct hw_perf_counter *hwc = &counter->hw;
3932         u64 now;
3933
3934         now = counter->ctx->time;
3935
3936         atomic64_set(&hwc->prev_count, now);
3937         hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
3938         hwc->hrtimer.function = perf_swcounter_hrtimer;
3939         if (hwc->sample_period) {
3940                 u64 period = max_t(u64, 10000, hwc->sample_period);
3941                 __hrtimer_start_range_ns(&hwc->hrtimer,
3942                                 ns_to_ktime(period), 0,
3943                                 HRTIMER_MODE_REL, 0);
3944         }
3945
3946         return 0;
3947 }
3948
3949 static void task_clock_perf_counter_disable(struct perf_counter *counter)
3950 {
3951         if (counter->hw.sample_period)
3952                 hrtimer_cancel(&counter->hw.hrtimer);
3953         task_clock_perf_counter_update(counter, counter->ctx->time);
3954
3955 }
3956
3957 static void task_clock_perf_counter_read(struct perf_counter *counter)
3958 {
3959         u64 time;
3960
3961         if (!in_nmi()) {
3962                 update_context_time(counter->ctx);
3963                 time = counter->ctx->time;
3964         } else {
3965                 u64 now = perf_clock();
3966                 u64 delta = now - counter->ctx->timestamp;
3967                 time = counter->ctx->time + delta;
3968         }
3969
3970         task_clock_perf_counter_update(counter, time);
3971 }
3972
3973 static const struct pmu perf_ops_task_clock = {
3974         .enable         = task_clock_perf_counter_enable,
3975         .disable        = task_clock_perf_counter_disable,
3976         .read           = task_clock_perf_counter_read,
3977 };
3978
3979 #ifdef CONFIG_EVENT_PROFILE
3980 void perf_tpcounter_event(int event_id, u64 addr, u64 count, void *record,
3981                           int entry_size)
3982 {
3983         struct perf_raw_record raw = {
3984                 .size = entry_size,
3985                 .data = record,
3986         };
3987
3988         struct perf_sample_data data = {
3989                 .addr = addr,
3990                 .raw = &raw,
3991         };
3992
3993         struct pt_regs *regs = get_irq_regs();
3994
3995         if (!regs)
3996                 regs = task_pt_regs(current);
3997
3998         do_perf_swcounter_event(PERF_TYPE_TRACEPOINT, event_id, count, 1,
3999                                 &data, regs);
4000 }
4001 EXPORT_SYMBOL_GPL(perf_tpcounter_event);
4002
4003 extern int ftrace_profile_enable(int);
4004 extern void ftrace_profile_disable(int);
4005
4006 static void tp_perf_counter_destroy(struct perf_counter *counter)
4007 {
4008         ftrace_profile_disable(counter->attr.config);
4009 }
4010
4011 static const struct pmu *tp_perf_counter_init(struct perf_counter *counter)
4012 {
4013         /*
4014          * Raw tracepoint data is a severe data leak, only allow root to
4015          * have these.
4016          */
4017         if ((counter->attr.sample_type & PERF_SAMPLE_RAW) &&
4018                         perf_paranoid_tracepoint_raw() &&
4019                         !capable(CAP_SYS_ADMIN))
4020                 return ERR_PTR(-EPERM);
4021
4022         if (ftrace_profile_enable(counter->attr.config))
4023                 return NULL;
4024
4025         counter->destroy = tp_perf_counter_destroy;
4026
4027         return &perf_ops_generic;
4028 }
4029 #else
4030 static const struct pmu *tp_perf_counter_init(struct perf_counter *counter)
4031 {
4032         return NULL;
4033 }
4034 #endif
4035
4036 atomic_t perf_swcounter_enabled[PERF_COUNT_SW_MAX];
4037
4038 static void sw_perf_counter_destroy(struct perf_counter *counter)
4039 {
4040         u64 event = counter->attr.config;
4041
4042         WARN_ON(counter->parent);
4043
4044         atomic_dec(&perf_swcounter_enabled[event]);
4045 }
4046
4047 static const struct pmu *sw_perf_counter_init(struct perf_counter *counter)
4048 {
4049         const struct pmu *pmu = NULL;
4050         u64 event = counter->attr.config;
4051
4052         /*
4053          * Software counters (currently) can't in general distinguish
4054          * between user, kernel and hypervisor events.
4055          * However, context switches and cpu migrations are considered
4056          * to be kernel events, and page faults are never hypervisor
4057          * events.
4058          */
4059         switch (event) {
4060         case PERF_COUNT_SW_CPU_CLOCK:
4061                 pmu = &perf_ops_cpu_clock;
4062
4063                 break;
4064         case PERF_COUNT_SW_TASK_CLOCK:
4065                 /*
4066                  * If the user instantiates this as a per-cpu counter,
4067                  * use the cpu_clock counter instead.
4068                  */
4069                 if (counter->ctx->task)
4070                         pmu = &perf_ops_task_clock;
4071                 else
4072                         pmu = &perf_ops_cpu_clock;
4073
4074                 break;
4075         case PERF_COUNT_SW_PAGE_FAULTS:
4076         case PERF_COUNT_SW_PAGE_FAULTS_MIN:
4077         case PERF_COUNT_SW_PAGE_FAULTS_MAJ:
4078         case PERF_COUNT_SW_CONTEXT_SWITCHES:
4079         case PERF_COUNT_SW_CPU_MIGRATIONS:
4080                 if (!counter->parent) {
4081                         atomic_inc(&perf_swcounter_enabled[event]);
4082                         counter->destroy = sw_perf_counter_destroy;
4083                 }
4084                 pmu = &perf_ops_generic;
4085                 break;
4086         }
4087
4088         return pmu;
4089 }
4090
4091 /*
4092  * Allocate and initialize a counter structure
4093  */
4094 static struct perf_counter *
4095 perf_counter_alloc(struct perf_counter_attr *attr,
4096                    int cpu,
4097                    struct perf_counter_context *ctx,
4098                    struct perf_counter *group_leader,
4099                    struct perf_counter *parent_counter,
4100                    gfp_t gfpflags)
4101 {
4102         const struct pmu *pmu;
4103         struct perf_counter *counter;
4104         struct hw_perf_counter *hwc;
4105         long err;
4106
4107         counter = kzalloc(sizeof(*counter), gfpflags);
4108         if (!counter)
4109                 return ERR_PTR(-ENOMEM);
4110
4111         /*
4112          * Single counters are their own group leaders, with an
4113          * empty sibling list:
4114          */
4115         if (!group_leader)
<