perf: export perf_trace_regs and perf_arch_fetch_caller_regs
[linux-2.6.git] / arch / x86 / kernel / cpu / perf_event.c
1 /*
2  * Performance events x86 architecture code
3  *
4  *  Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5  *  Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
6  *  Copyright (C) 2009 Jaswinder Singh Rajput
7  *  Copyright (C) 2009 Advanced Micro Devices, Inc., Robert Richter
8  *  Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
9  *  Copyright (C) 2009 Intel Corporation, <markus.t.metzger@intel.com>
10  *  Copyright (C) 2009 Google, Inc., Stephane Eranian
11  *
12  *  For licencing details see kernel-base/COPYING
13  */
14
15 #include <linux/perf_event.h>
16 #include <linux/capability.h>
17 #include <linux/notifier.h>
18 #include <linux/hardirq.h>
19 #include <linux/kprobes.h>
20 #include <linux/module.h>
21 #include <linux/kdebug.h>
22 #include <linux/sched.h>
23 #include <linux/uaccess.h>
24 #include <linux/highmem.h>
25 #include <linux/cpu.h>
26 #include <linux/bitops.h>
27
28 #include <asm/apic.h>
29 #include <asm/stacktrace.h>
30 #include <asm/nmi.h>
31
32 static u64 perf_event_mask __read_mostly;
33
34 /* The maximal number of PEBS events: */
35 #define MAX_PEBS_EVENTS 4
36
37 /* The size of a BTS record in bytes: */
38 #define BTS_RECORD_SIZE         24
39
40 /* The size of a per-cpu BTS buffer in bytes: */
41 #define BTS_BUFFER_SIZE         (BTS_RECORD_SIZE * 2048)
42
43 /* The BTS overflow threshold in bytes from the end of the buffer: */
44 #define BTS_OVFL_TH             (BTS_RECORD_SIZE * 128)
45
46
47 /*
48  * Bits in the debugctlmsr controlling branch tracing.
49  */
50 #define X86_DEBUGCTL_TR                 (1 << 6)
51 #define X86_DEBUGCTL_BTS                (1 << 7)
52 #define X86_DEBUGCTL_BTINT              (1 << 8)
53 #define X86_DEBUGCTL_BTS_OFF_OS         (1 << 9)
54 #define X86_DEBUGCTL_BTS_OFF_USR        (1 << 10)
55
56 /*
57  * A debug store configuration.
58  *
59  * We only support architectures that use 64bit fields.
60  */
61 struct debug_store {
62         u64     bts_buffer_base;
63         u64     bts_index;
64         u64     bts_absolute_maximum;
65         u64     bts_interrupt_threshold;
66         u64     pebs_buffer_base;
67         u64     pebs_index;
68         u64     pebs_absolute_maximum;
69         u64     pebs_interrupt_threshold;
70         u64     pebs_event_reset[MAX_PEBS_EVENTS];
71 };
72
73 struct event_constraint {
74         union {
75                 unsigned long   idxmsk[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
76                 u64             idxmsk64;
77         };
78         u64     code;
79         u64     cmask;
80         int     weight;
81 };
82
83 struct amd_nb {
84         int nb_id;  /* NorthBridge id */
85         int refcnt; /* reference count */
86         struct perf_event *owners[X86_PMC_IDX_MAX];
87         struct event_constraint event_constraints[X86_PMC_IDX_MAX];
88 };
89
90 struct cpu_hw_events {
91         struct perf_event       *events[X86_PMC_IDX_MAX]; /* in counter order */
92         unsigned long           active_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
93         unsigned long           interrupts;
94         int                     enabled;
95         struct debug_store      *ds;
96
97         int                     n_events;
98         int                     n_added;
99         int                     assign[X86_PMC_IDX_MAX]; /* event to counter assignment */
100         u64                     tags[X86_PMC_IDX_MAX];
101         struct perf_event       *event_list[X86_PMC_IDX_MAX]; /* in enabled order */
102         struct amd_nb           *amd_nb;
103 };
104
105 #define __EVENT_CONSTRAINT(c, n, m, w) {\
106         { .idxmsk64 = (n) },            \
107         .code = (c),                    \
108         .cmask = (m),                   \
109         .weight = (w),                  \
110 }
111
112 #define EVENT_CONSTRAINT(c, n, m)       \
113         __EVENT_CONSTRAINT(c, n, m, HWEIGHT(n))
114
115 #define INTEL_EVENT_CONSTRAINT(c, n)    \
116         EVENT_CONSTRAINT(c, n, INTEL_ARCH_EVTSEL_MASK)
117
118 #define FIXED_EVENT_CONSTRAINT(c, n)    \
119         EVENT_CONSTRAINT(c, (1ULL << (32+n)), INTEL_ARCH_FIXED_MASK)
120
121 #define EVENT_CONSTRAINT_END            \
122         EVENT_CONSTRAINT(0, 0, 0)
123
124 #define for_each_event_constraint(e, c) \
125         for ((e) = (c); (e)->cmask; (e)++)
126
127 /*
128  * struct x86_pmu - generic x86 pmu
129  */
130 struct x86_pmu {
131         const char      *name;
132         int             version;
133         int             (*handle_irq)(struct pt_regs *);
134         void            (*disable_all)(void);
135         void            (*enable_all)(void);
136         void            (*enable)(struct perf_event *);
137         void            (*disable)(struct perf_event *);
138         unsigned        eventsel;
139         unsigned        perfctr;
140         u64             (*event_map)(int);
141         u64             (*raw_event)(u64);
142         int             max_events;
143         int             num_events;
144         int             num_events_fixed;
145         int             event_bits;
146         u64             event_mask;
147         int             apic;
148         u64             max_period;
149         u64             intel_ctrl;
150         void            (*enable_bts)(u64 config);
151         void            (*disable_bts)(void);
152
153         struct event_constraint *
154                         (*get_event_constraints)(struct cpu_hw_events *cpuc,
155                                                  struct perf_event *event);
156
157         void            (*put_event_constraints)(struct cpu_hw_events *cpuc,
158                                                  struct perf_event *event);
159         struct event_constraint *event_constraints;
160
161         void            (*cpu_prepare)(int cpu);
162         void            (*cpu_starting)(int cpu);
163         void            (*cpu_dying)(int cpu);
164         void            (*cpu_dead)(int cpu);
165 };
166
167 static struct x86_pmu x86_pmu __read_mostly;
168
169 static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = {
170         .enabled = 1,
171 };
172
173 static int x86_perf_event_set_period(struct perf_event *event);
174
175 /*
176  * Generalized hw caching related hw_event table, filled
177  * in on a per model basis. A value of 0 means
178  * 'not supported', -1 means 'hw_event makes no sense on
179  * this CPU', any other value means the raw hw_event
180  * ID.
181  */
182
183 #define C(x) PERF_COUNT_HW_CACHE_##x
184
185 static u64 __read_mostly hw_cache_event_ids
186                                 [PERF_COUNT_HW_CACHE_MAX]
187                                 [PERF_COUNT_HW_CACHE_OP_MAX]
188                                 [PERF_COUNT_HW_CACHE_RESULT_MAX];
189
190 /*
191  * Propagate event elapsed time into the generic event.
192  * Can only be executed on the CPU where the event is active.
193  * Returns the delta events processed.
194  */
195 static u64
196 x86_perf_event_update(struct perf_event *event)
197 {
198         struct hw_perf_event *hwc = &event->hw;
199         int shift = 64 - x86_pmu.event_bits;
200         u64 prev_raw_count, new_raw_count;
201         int idx = hwc->idx;
202         s64 delta;
203
204         if (idx == X86_PMC_IDX_FIXED_BTS)
205                 return 0;
206
207         /*
208          * Careful: an NMI might modify the previous event value.
209          *
210          * Our tactic to handle this is to first atomically read and
211          * exchange a new raw count - then add that new-prev delta
212          * count to the generic event atomically:
213          */
214 again:
215         prev_raw_count = atomic64_read(&hwc->prev_count);
216         rdmsrl(hwc->event_base + idx, new_raw_count);
217
218         if (atomic64_cmpxchg(&hwc->prev_count, prev_raw_count,
219                                         new_raw_count) != prev_raw_count)
220                 goto again;
221
222         /*
223          * Now we have the new raw value and have updated the prev
224          * timestamp already. We can now calculate the elapsed delta
225          * (event-)time and add that to the generic event.
226          *
227          * Careful, not all hw sign-extends above the physical width
228          * of the count.
229          */
230         delta = (new_raw_count << shift) - (prev_raw_count << shift);
231         delta >>= shift;
232
233         atomic64_add(delta, &event->count);
234         atomic64_sub(delta, &hwc->period_left);
235
236         return new_raw_count;
237 }
238
239 static atomic_t active_events;
240 static DEFINE_MUTEX(pmc_reserve_mutex);
241
242 static bool reserve_pmc_hardware(void)
243 {
244 #ifdef CONFIG_X86_LOCAL_APIC
245         int i;
246
247         if (nmi_watchdog == NMI_LOCAL_APIC)
248                 disable_lapic_nmi_watchdog();
249
250         for (i = 0; i < x86_pmu.num_events; i++) {
251                 if (!reserve_perfctr_nmi(x86_pmu.perfctr + i))
252                         goto perfctr_fail;
253         }
254
255         for (i = 0; i < x86_pmu.num_events; i++) {
256                 if (!reserve_evntsel_nmi(x86_pmu.eventsel + i))
257                         goto eventsel_fail;
258         }
259 #endif
260
261         return true;
262
263 #ifdef CONFIG_X86_LOCAL_APIC
264 eventsel_fail:
265         for (i--; i >= 0; i--)
266                 release_evntsel_nmi(x86_pmu.eventsel + i);
267
268         i = x86_pmu.num_events;
269
270 perfctr_fail:
271         for (i--; i >= 0; i--)
272                 release_perfctr_nmi(x86_pmu.perfctr + i);
273
274         if (nmi_watchdog == NMI_LOCAL_APIC)
275                 enable_lapic_nmi_watchdog();
276
277         return false;
278 #endif
279 }
280
281 static void release_pmc_hardware(void)
282 {
283 #ifdef CONFIG_X86_LOCAL_APIC
284         int i;
285
286         for (i = 0; i < x86_pmu.num_events; i++) {
287                 release_perfctr_nmi(x86_pmu.perfctr + i);
288                 release_evntsel_nmi(x86_pmu.eventsel + i);
289         }
290
291         if (nmi_watchdog == NMI_LOCAL_APIC)
292                 enable_lapic_nmi_watchdog();
293 #endif
294 }
295
296 static inline bool bts_available(void)
297 {
298         return x86_pmu.enable_bts != NULL;
299 }
300
301 static void init_debug_store_on_cpu(int cpu)
302 {
303         struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
304
305         if (!ds)
306                 return;
307
308         wrmsr_on_cpu(cpu, MSR_IA32_DS_AREA,
309                      (u32)((u64)(unsigned long)ds),
310                      (u32)((u64)(unsigned long)ds >> 32));
311 }
312
313 static void fini_debug_store_on_cpu(int cpu)
314 {
315         if (!per_cpu(cpu_hw_events, cpu).ds)
316                 return;
317
318         wrmsr_on_cpu(cpu, MSR_IA32_DS_AREA, 0, 0);
319 }
320
321 static void release_bts_hardware(void)
322 {
323         int cpu;
324
325         if (!bts_available())
326                 return;
327
328         get_online_cpus();
329
330         for_each_online_cpu(cpu)
331                 fini_debug_store_on_cpu(cpu);
332
333         for_each_possible_cpu(cpu) {
334                 struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
335
336                 if (!ds)
337                         continue;
338
339                 per_cpu(cpu_hw_events, cpu).ds = NULL;
340
341                 kfree((void *)(unsigned long)ds->bts_buffer_base);
342                 kfree(ds);
343         }
344
345         put_online_cpus();
346 }
347
348 static int reserve_bts_hardware(void)
349 {
350         int cpu, err = 0;
351
352         if (!bts_available())
353                 return 0;
354
355         get_online_cpus();
356
357         for_each_possible_cpu(cpu) {
358                 struct debug_store *ds;
359                 void *buffer;
360
361                 err = -ENOMEM;
362                 buffer = kzalloc(BTS_BUFFER_SIZE, GFP_KERNEL);
363                 if (unlikely(!buffer))
364                         break;
365
366                 ds = kzalloc(sizeof(*ds), GFP_KERNEL);
367                 if (unlikely(!ds)) {
368                         kfree(buffer);
369                         break;
370                 }
371
372                 ds->bts_buffer_base = (u64)(unsigned long)buffer;
373                 ds->bts_index = ds->bts_buffer_base;
374                 ds->bts_absolute_maximum =
375                         ds->bts_buffer_base + BTS_BUFFER_SIZE;
376                 ds->bts_interrupt_threshold =
377                         ds->bts_absolute_maximum - BTS_OVFL_TH;
378
379                 per_cpu(cpu_hw_events, cpu).ds = ds;
380                 err = 0;
381         }
382
383         if (err)
384                 release_bts_hardware();
385         else {
386                 for_each_online_cpu(cpu)
387                         init_debug_store_on_cpu(cpu);
388         }
389
390         put_online_cpus();
391
392         return err;
393 }
394
395 static void hw_perf_event_destroy(struct perf_event *event)
396 {
397         if (atomic_dec_and_mutex_lock(&active_events, &pmc_reserve_mutex)) {
398                 release_pmc_hardware();
399                 release_bts_hardware();
400                 mutex_unlock(&pmc_reserve_mutex);
401         }
402 }
403
404 static inline int x86_pmu_initialized(void)
405 {
406         return x86_pmu.handle_irq != NULL;
407 }
408
409 static inline int
410 set_ext_hw_attr(struct hw_perf_event *hwc, struct perf_event_attr *attr)
411 {
412         unsigned int cache_type, cache_op, cache_result;
413         u64 config, val;
414
415         config = attr->config;
416
417         cache_type = (config >>  0) & 0xff;
418         if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
419                 return -EINVAL;
420
421         cache_op = (config >>  8) & 0xff;
422         if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
423                 return -EINVAL;
424
425         cache_result = (config >> 16) & 0xff;
426         if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
427                 return -EINVAL;
428
429         val = hw_cache_event_ids[cache_type][cache_op][cache_result];
430
431         if (val == 0)
432                 return -ENOENT;
433
434         if (val == -1)
435                 return -EINVAL;
436
437         hwc->config |= val;
438
439         return 0;
440 }
441
442 /*
443  * Setup the hardware configuration for a given attr_type
444  */
445 static int __hw_perf_event_init(struct perf_event *event)
446 {
447         struct perf_event_attr *attr = &event->attr;
448         struct hw_perf_event *hwc = &event->hw;
449         u64 config;
450         int err;
451
452         if (!x86_pmu_initialized())
453                 return -ENODEV;
454
455         err = 0;
456         if (!atomic_inc_not_zero(&active_events)) {
457                 mutex_lock(&pmc_reserve_mutex);
458                 if (atomic_read(&active_events) == 0) {
459                         if (!reserve_pmc_hardware())
460                                 err = -EBUSY;
461                         else
462                                 err = reserve_bts_hardware();
463                 }
464                 if (!err)
465                         atomic_inc(&active_events);
466                 mutex_unlock(&pmc_reserve_mutex);
467         }
468         if (err)
469                 return err;
470
471         event->destroy = hw_perf_event_destroy;
472
473         /*
474          * Generate PMC IRQs:
475          * (keep 'enabled' bit clear for now)
476          */
477         hwc->config = ARCH_PERFMON_EVENTSEL_INT;
478
479         hwc->idx = -1;
480         hwc->last_cpu = -1;
481         hwc->last_tag = ~0ULL;
482
483         /*
484          * Count user and OS events unless requested not to.
485          */
486         if (!attr->exclude_user)
487                 hwc->config |= ARCH_PERFMON_EVENTSEL_USR;
488         if (!attr->exclude_kernel)
489                 hwc->config |= ARCH_PERFMON_EVENTSEL_OS;
490
491         if (!hwc->sample_period) {
492                 hwc->sample_period = x86_pmu.max_period;
493                 hwc->last_period = hwc->sample_period;
494                 atomic64_set(&hwc->period_left, hwc->sample_period);
495         } else {
496                 /*
497                  * If we have a PMU initialized but no APIC
498                  * interrupts, we cannot sample hardware
499                  * events (user-space has to fall back and
500                  * sample via a hrtimer based software event):
501                  */
502                 if (!x86_pmu.apic)
503                         return -EOPNOTSUPP;
504         }
505
506         /*
507          * Raw hw_event type provide the config in the hw_event structure
508          */
509         if (attr->type == PERF_TYPE_RAW) {
510                 hwc->config |= x86_pmu.raw_event(attr->config);
511                 if ((hwc->config & ARCH_PERFMON_EVENTSEL_ANY) &&
512                     perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
513                         return -EACCES;
514                 return 0;
515         }
516
517         if (attr->type == PERF_TYPE_HW_CACHE)
518                 return set_ext_hw_attr(hwc, attr);
519
520         if (attr->config >= x86_pmu.max_events)
521                 return -EINVAL;
522
523         /*
524          * The generic map:
525          */
526         config = x86_pmu.event_map(attr->config);
527
528         if (config == 0)
529                 return -ENOENT;
530
531         if (config == -1LL)
532                 return -EINVAL;
533
534         /*
535          * Branch tracing:
536          */
537         if ((attr->config == PERF_COUNT_HW_BRANCH_INSTRUCTIONS) &&
538             (hwc->sample_period == 1)) {
539                 /* BTS is not supported by this architecture. */
540                 if (!bts_available())
541                         return -EOPNOTSUPP;
542
543                 /* BTS is currently only allowed for user-mode. */
544                 if (hwc->config & ARCH_PERFMON_EVENTSEL_OS)
545                         return -EOPNOTSUPP;
546         }
547
548         hwc->config |= config;
549
550         return 0;
551 }
552
553 static void x86_pmu_disable_all(void)
554 {
555         struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
556         int idx;
557
558         for (idx = 0; idx < x86_pmu.num_events; idx++) {
559                 u64 val;
560
561                 if (!test_bit(idx, cpuc->active_mask))
562                         continue;
563                 rdmsrl(x86_pmu.eventsel + idx, val);
564                 if (!(val & ARCH_PERFMON_EVENTSEL_ENABLE))
565                         continue;
566                 val &= ~ARCH_PERFMON_EVENTSEL_ENABLE;
567                 wrmsrl(x86_pmu.eventsel + idx, val);
568         }
569 }
570
571 void hw_perf_disable(void)
572 {
573         struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
574
575         if (!x86_pmu_initialized())
576                 return;
577
578         if (!cpuc->enabled)
579                 return;
580
581         cpuc->n_added = 0;
582         cpuc->enabled = 0;
583         barrier();
584
585         x86_pmu.disable_all();
586 }
587
588 static void x86_pmu_enable_all(void)
589 {
590         struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
591         int idx;
592
593         for (idx = 0; idx < x86_pmu.num_events; idx++) {
594                 struct perf_event *event = cpuc->events[idx];
595                 u64 val;
596
597                 if (!test_bit(idx, cpuc->active_mask))
598                         continue;
599
600                 val = event->hw.config;
601                 val |= ARCH_PERFMON_EVENTSEL_ENABLE;
602                 wrmsrl(x86_pmu.eventsel + idx, val);
603         }
604 }
605
606 static const struct pmu pmu;
607
608 static inline int is_x86_event(struct perf_event *event)
609 {
610         return event->pmu == &pmu;
611 }
612
613 static int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign)
614 {
615         struct event_constraint *c, *constraints[X86_PMC_IDX_MAX];
616         unsigned long used_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
617         int i, j, w, wmax, num = 0;
618         struct hw_perf_event *hwc;
619
620         bitmap_zero(used_mask, X86_PMC_IDX_MAX);
621
622         for (i = 0; i < n; i++) {
623                 c = x86_pmu.get_event_constraints(cpuc, cpuc->event_list[i]);
624                 constraints[i] = c;
625         }
626
627         /*
628          * fastpath, try to reuse previous register
629          */
630         for (i = 0; i < n; i++) {
631                 hwc = &cpuc->event_list[i]->hw;
632                 c = constraints[i];
633
634                 /* never assigned */
635                 if (hwc->idx == -1)
636                         break;
637
638                 /* constraint still honored */
639                 if (!test_bit(hwc->idx, c->idxmsk))
640                         break;
641
642                 /* not already used */
643                 if (test_bit(hwc->idx, used_mask))
644                         break;
645
646                 __set_bit(hwc->idx, used_mask);
647                 if (assign)
648                         assign[i] = hwc->idx;
649         }
650         if (i == n)
651                 goto done;
652
653         /*
654          * begin slow path
655          */
656
657         bitmap_zero(used_mask, X86_PMC_IDX_MAX);
658
659         /*
660          * weight = number of possible counters
661          *
662          * 1    = most constrained, only works on one counter
663          * wmax = least constrained, works on any counter
664          *
665          * assign events to counters starting with most
666          * constrained events.
667          */
668         wmax = x86_pmu.num_events;
669
670         /*
671          * when fixed event counters are present,
672          * wmax is incremented by 1 to account
673          * for one more choice
674          */
675         if (x86_pmu.num_events_fixed)
676                 wmax++;
677
678         for (w = 1, num = n; num && w <= wmax; w++) {
679                 /* for each event */
680                 for (i = 0; num && i < n; i++) {
681                         c = constraints[i];
682                         hwc = &cpuc->event_list[i]->hw;
683
684                         if (c->weight != w)
685                                 continue;
686
687                         for_each_set_bit(j, c->idxmsk, X86_PMC_IDX_MAX) {
688                                 if (!test_bit(j, used_mask))
689                                         break;
690                         }
691
692                         if (j == X86_PMC_IDX_MAX)
693                                 break;
694
695                         __set_bit(j, used_mask);
696
697                         if (assign)
698                                 assign[i] = j;
699                         num--;
700                 }
701         }
702 done:
703         /*
704          * scheduling failed or is just a simulation,
705          * free resources if necessary
706          */
707         if (!assign || num) {
708                 for (i = 0; i < n; i++) {
709                         if (x86_pmu.put_event_constraints)
710                                 x86_pmu.put_event_constraints(cpuc, cpuc->event_list[i]);
711                 }
712         }
713         return num ? -ENOSPC : 0;
714 }
715
716 /*
717  * dogrp: true if must collect siblings events (group)
718  * returns total number of events and error code
719  */
720 static int collect_events(struct cpu_hw_events *cpuc, struct perf_event *leader, bool dogrp)
721 {
722         struct perf_event *event;
723         int n, max_count;
724
725         max_count = x86_pmu.num_events + x86_pmu.num_events_fixed;
726
727         /* current number of events already accepted */
728         n = cpuc->n_events;
729
730         if (is_x86_event(leader)) {
731                 if (n >= max_count)
732                         return -ENOSPC;
733                 cpuc->event_list[n] = leader;
734                 n++;
735         }
736         if (!dogrp)
737                 return n;
738
739         list_for_each_entry(event, &leader->sibling_list, group_entry) {
740                 if (!is_x86_event(event) ||
741                     event->state <= PERF_EVENT_STATE_OFF)
742                         continue;
743
744                 if (n >= max_count)
745                         return -ENOSPC;
746
747                 cpuc->event_list[n] = event;
748                 n++;
749         }
750         return n;
751 }
752
753 static inline void x86_assign_hw_event(struct perf_event *event,
754                                 struct cpu_hw_events *cpuc, int i)
755 {
756         struct hw_perf_event *hwc = &event->hw;
757
758         hwc->idx = cpuc->assign[i];
759         hwc->last_cpu = smp_processor_id();
760         hwc->last_tag = ++cpuc->tags[i];
761
762         if (hwc->idx == X86_PMC_IDX_FIXED_BTS) {
763                 hwc->config_base = 0;
764                 hwc->event_base = 0;
765         } else if (hwc->idx >= X86_PMC_IDX_FIXED) {
766                 hwc->config_base = MSR_ARCH_PERFMON_FIXED_CTR_CTRL;
767                 /*
768                  * We set it so that event_base + idx in wrmsr/rdmsr maps to
769                  * MSR_ARCH_PERFMON_FIXED_CTR0 ... CTR2:
770                  */
771                 hwc->event_base =
772                         MSR_ARCH_PERFMON_FIXED_CTR0 - X86_PMC_IDX_FIXED;
773         } else {
774                 hwc->config_base = x86_pmu.eventsel;
775                 hwc->event_base  = x86_pmu.perfctr;
776         }
777 }
778
779 static inline int match_prev_assignment(struct hw_perf_event *hwc,
780                                         struct cpu_hw_events *cpuc,
781                                         int i)
782 {
783         return hwc->idx == cpuc->assign[i] &&
784                 hwc->last_cpu == smp_processor_id() &&
785                 hwc->last_tag == cpuc->tags[i];
786 }
787
788 static int x86_pmu_start(struct perf_event *event);
789 static void x86_pmu_stop(struct perf_event *event);
790
791 void hw_perf_enable(void)
792 {
793         struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
794         struct perf_event *event;
795         struct hw_perf_event *hwc;
796         int i;
797
798         if (!x86_pmu_initialized())
799                 return;
800
801         if (cpuc->enabled)
802                 return;
803
804         if (cpuc->n_added) {
805                 int n_running = cpuc->n_events - cpuc->n_added;
806                 /*
807                  * apply assignment obtained either from
808                  * hw_perf_group_sched_in() or x86_pmu_enable()
809                  *
810                  * step1: save events moving to new counters
811                  * step2: reprogram moved events into new counters
812                  */
813                 for (i = 0; i < n_running; i++) {
814                         event = cpuc->event_list[i];
815                         hwc = &event->hw;
816
817                         /*
818                          * we can avoid reprogramming counter if:
819                          * - assigned same counter as last time
820                          * - running on same CPU as last time
821                          * - no other event has used the counter since
822                          */
823                         if (hwc->idx == -1 ||
824                             match_prev_assignment(hwc, cpuc, i))
825                                 continue;
826
827                         x86_pmu_stop(event);
828                 }
829
830                 for (i = 0; i < cpuc->n_events; i++) {
831                         event = cpuc->event_list[i];
832                         hwc = &event->hw;
833
834                         if (!match_prev_assignment(hwc, cpuc, i))
835                                 x86_assign_hw_event(event, cpuc, i);
836                         else if (i < n_running)
837                                 continue;
838
839                         x86_pmu_start(event);
840                 }
841                 cpuc->n_added = 0;
842                 perf_events_lapic_init();
843         }
844
845         cpuc->enabled = 1;
846         barrier();
847
848         x86_pmu.enable_all();
849 }
850
851 static inline void __x86_pmu_enable_event(struct hw_perf_event *hwc)
852 {
853         (void)checking_wrmsrl(hwc->config_base + hwc->idx,
854                               hwc->config | ARCH_PERFMON_EVENTSEL_ENABLE);
855 }
856
857 static inline void x86_pmu_disable_event(struct perf_event *event)
858 {
859         struct hw_perf_event *hwc = &event->hw;
860         (void)checking_wrmsrl(hwc->config_base + hwc->idx, hwc->config);
861 }
862
863 static DEFINE_PER_CPU(u64 [X86_PMC_IDX_MAX], pmc_prev_left);
864
865 /*
866  * Set the next IRQ period, based on the hwc->period_left value.
867  * To be called with the event disabled in hw:
868  */
869 static int
870 x86_perf_event_set_period(struct perf_event *event)
871 {
872         struct hw_perf_event *hwc = &event->hw;
873         s64 left = atomic64_read(&hwc->period_left);
874         s64 period = hwc->sample_period;
875         int err, ret = 0, idx = hwc->idx;
876
877         if (idx == X86_PMC_IDX_FIXED_BTS)
878                 return 0;
879
880         /*
881          * If we are way outside a reasonable range then just skip forward:
882          */
883         if (unlikely(left <= -period)) {
884                 left = period;
885                 atomic64_set(&hwc->period_left, left);
886                 hwc->last_period = period;
887                 ret = 1;
888         }
889
890         if (unlikely(left <= 0)) {
891                 left += period;
892                 atomic64_set(&hwc->period_left, left);
893                 hwc->last_period = period;
894                 ret = 1;
895         }
896         /*
897          * Quirk: certain CPUs dont like it if just 1 hw_event is left:
898          */
899         if (unlikely(left < 2))
900                 left = 2;
901
902         if (left > x86_pmu.max_period)
903                 left = x86_pmu.max_period;
904
905         per_cpu(pmc_prev_left[idx], smp_processor_id()) = left;
906
907         /*
908          * The hw event starts counting from this event offset,
909          * mark it to be able to extra future deltas:
910          */
911         atomic64_set(&hwc->prev_count, (u64)-left);
912
913         err = checking_wrmsrl(hwc->event_base + idx,
914                              (u64)(-left) & x86_pmu.event_mask);
915
916         perf_event_update_userpage(event);
917
918         return ret;
919 }
920
921 static void x86_pmu_enable_event(struct perf_event *event)
922 {
923         struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
924         if (cpuc->enabled)
925                 __x86_pmu_enable_event(&event->hw);
926 }
927
928 /*
929  * activate a single event
930  *
931  * The event is added to the group of enabled events
932  * but only if it can be scehduled with existing events.
933  *
934  * Called with PMU disabled. If successful and return value 1,
935  * then guaranteed to call perf_enable() and hw_perf_enable()
936  */
937 static int x86_pmu_enable(struct perf_event *event)
938 {
939         struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
940         struct hw_perf_event *hwc;
941         int assign[X86_PMC_IDX_MAX];
942         int n, n0, ret;
943
944         hwc = &event->hw;
945
946         n0 = cpuc->n_events;
947         n = collect_events(cpuc, event, false);
948         if (n < 0)
949                 return n;
950
951         ret = x86_schedule_events(cpuc, n, assign);
952         if (ret)
953                 return ret;
954         /*
955          * copy new assignment, now we know it is possible
956          * will be used by hw_perf_enable()
957          */
958         memcpy(cpuc->assign, assign, n*sizeof(int));
959
960         cpuc->n_events = n;
961         cpuc->n_added += n - n0;
962
963         return 0;
964 }
965
966 static int x86_pmu_start(struct perf_event *event)
967 {
968         struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
969         int idx = event->hw.idx;
970
971         if (idx == -1)
972                 return -EAGAIN;
973
974         x86_perf_event_set_period(event);
975         cpuc->events[idx] = event;
976         __set_bit(idx, cpuc->active_mask);
977         x86_pmu.enable(event);
978         perf_event_update_userpage(event);
979
980         return 0;
981 }
982
983 static void x86_pmu_unthrottle(struct perf_event *event)
984 {
985         int ret = x86_pmu_start(event);
986         WARN_ON_ONCE(ret);
987 }
988
989 void perf_event_print_debug(void)
990 {
991         u64 ctrl, status, overflow, pmc_ctrl, pmc_count, prev_left, fixed;
992         struct cpu_hw_events *cpuc;
993         unsigned long flags;
994         int cpu, idx;
995
996         if (!x86_pmu.num_events)
997                 return;
998
999         local_irq_save(flags);
1000
1001         cpu = smp_processor_id();
1002         cpuc = &per_cpu(cpu_hw_events, cpu);
1003
1004         if (x86_pmu.version >= 2) {
1005                 rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, ctrl);
1006                 rdmsrl(MSR_CORE_PERF_GLOBAL_STATUS, status);
1007                 rdmsrl(MSR_CORE_PERF_GLOBAL_OVF_CTRL, overflow);
1008                 rdmsrl(MSR_ARCH_PERFMON_FIXED_CTR_CTRL, fixed);
1009
1010                 pr_info("\n");
1011                 pr_info("CPU#%d: ctrl:       %016llx\n", cpu, ctrl);
1012                 pr_info("CPU#%d: status:     %016llx\n", cpu, status);
1013                 pr_info("CPU#%d: overflow:   %016llx\n", cpu, overflow);
1014                 pr_info("CPU#%d: fixed:      %016llx\n", cpu, fixed);
1015         }
1016         pr_info("CPU#%d: active:       %016llx\n", cpu, *(u64 *)cpuc->active_mask);
1017
1018         for (idx = 0; idx < x86_pmu.num_events; idx++) {
1019                 rdmsrl(x86_pmu.eventsel + idx, pmc_ctrl);
1020                 rdmsrl(x86_pmu.perfctr  + idx, pmc_count);
1021
1022                 prev_left = per_cpu(pmc_prev_left[idx], cpu);
1023
1024                 pr_info("CPU#%d:   gen-PMC%d ctrl:  %016llx\n",
1025                         cpu, idx, pmc_ctrl);
1026                 pr_info("CPU#%d:   gen-PMC%d count: %016llx\n",
1027                         cpu, idx, pmc_count);
1028                 pr_info("CPU#%d:   gen-PMC%d left:  %016llx\n",
1029                         cpu, idx, prev_left);
1030         }
1031         for (idx = 0; idx < x86_pmu.num_events_fixed; idx++) {
1032                 rdmsrl(MSR_ARCH_PERFMON_FIXED_CTR0 + idx, pmc_count);
1033
1034                 pr_info("CPU#%d: fixed-PMC%d count: %016llx\n",
1035                         cpu, idx, pmc_count);
1036         }
1037         local_irq_restore(flags);
1038 }
1039
1040 static void x86_pmu_stop(struct perf_event *event)
1041 {
1042         struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
1043         struct hw_perf_event *hwc = &event->hw;
1044         int idx = hwc->idx;
1045
1046         if (!__test_and_clear_bit(idx, cpuc->active_mask))
1047                 return;
1048
1049         x86_pmu.disable(event);
1050
1051         /*
1052          * Drain the remaining delta count out of a event
1053          * that we are disabling:
1054          */
1055         x86_perf_event_update(event);
1056
1057         cpuc->events[idx] = NULL;
1058 }
1059
1060 static void x86_pmu_disable(struct perf_event *event)
1061 {
1062         struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
1063         int i;
1064
1065         x86_pmu_stop(event);
1066
1067         for (i = 0; i < cpuc->n_events; i++) {
1068                 if (event == cpuc->event_list[i]) {
1069
1070                         if (x86_pmu.put_event_constraints)
1071                                 x86_pmu.put_event_constraints(cpuc, event);
1072
1073                         while (++i < cpuc->n_events)
1074                                 cpuc->event_list[i-1] = cpuc->event_list[i];
1075
1076                         --cpuc->n_events;
1077                         break;
1078                 }
1079         }
1080         perf_event_update_userpage(event);
1081 }
1082
1083 static int x86_pmu_handle_irq(struct pt_regs *regs)
1084 {
1085         struct perf_sample_data data;
1086         struct cpu_hw_events *cpuc;
1087         struct perf_event *event;
1088         struct hw_perf_event *hwc;
1089         int idx, handled = 0;
1090         u64 val;
1091
1092         perf_sample_data_init(&data, 0);
1093
1094         cpuc = &__get_cpu_var(cpu_hw_events);
1095
1096         for (idx = 0; idx < x86_pmu.num_events; idx++) {
1097                 if (!test_bit(idx, cpuc->active_mask))
1098                         continue;
1099
1100                 event = cpuc->events[idx];
1101                 hwc = &event->hw;
1102
1103                 val = x86_perf_event_update(event);
1104                 if (val & (1ULL << (x86_pmu.event_bits - 1)))
1105                         continue;
1106
1107                 /*
1108                  * event overflow
1109                  */
1110                 handled         = 1;
1111                 data.period     = event->hw.last_period;
1112
1113                 if (!x86_perf_event_set_period(event))
1114                         continue;
1115
1116                 if (perf_event_overflow(event, 1, &data, regs))
1117                         x86_pmu_stop(event);
1118         }
1119
1120         if (handled)
1121                 inc_irq_stat(apic_perf_irqs);
1122
1123         return handled;
1124 }
1125
1126 void smp_perf_pending_interrupt(struct pt_regs *regs)
1127 {
1128         irq_enter();
1129         ack_APIC_irq();
1130         inc_irq_stat(apic_pending_irqs);
1131         perf_event_do_pending();
1132         irq_exit();
1133 }
1134
1135 void set_perf_event_pending(void)
1136 {
1137 #ifdef CONFIG_X86_LOCAL_APIC
1138         if (!x86_pmu.apic || !x86_pmu_initialized())
1139                 return;
1140
1141         apic->send_IPI_self(LOCAL_PENDING_VECTOR);
1142 #endif
1143 }
1144
1145 void perf_events_lapic_init(void)
1146 {
1147 #ifdef CONFIG_X86_LOCAL_APIC
1148         if (!x86_pmu.apic || !x86_pmu_initialized())
1149                 return;
1150
1151         /*
1152          * Always use NMI for PMU
1153          */
1154         apic_write(APIC_LVTPC, APIC_DM_NMI);
1155 #endif
1156 }
1157
1158 static int __kprobes
1159 perf_event_nmi_handler(struct notifier_block *self,
1160                          unsigned long cmd, void *__args)
1161 {
1162         struct die_args *args = __args;
1163         struct pt_regs *regs;
1164
1165         if (!atomic_read(&active_events))
1166                 return NOTIFY_DONE;
1167
1168         switch (cmd) {
1169         case DIE_NMI:
1170         case DIE_NMI_IPI:
1171                 break;
1172
1173         default:
1174                 return NOTIFY_DONE;
1175         }
1176
1177         regs = args->regs;
1178
1179 #ifdef CONFIG_X86_LOCAL_APIC
1180         apic_write(APIC_LVTPC, APIC_DM_NMI);
1181 #endif
1182         /*
1183          * Can't rely on the handled return value to say it was our NMI, two
1184          * events could trigger 'simultaneously' raising two back-to-back NMIs.
1185          *
1186          * If the first NMI handles both, the latter will be empty and daze
1187          * the CPU.
1188          */
1189         x86_pmu.handle_irq(regs);
1190
1191         return NOTIFY_STOP;
1192 }
1193
1194 static __read_mostly struct notifier_block perf_event_nmi_notifier = {
1195         .notifier_call          = perf_event_nmi_handler,
1196         .next                   = NULL,
1197         .priority               = 1
1198 };
1199
1200 static struct event_constraint unconstrained;
1201 static struct event_constraint emptyconstraint;
1202
1203 static struct event_constraint *
1204 x86_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event)
1205 {
1206         struct event_constraint *c;
1207
1208         if (x86_pmu.event_constraints) {
1209                 for_each_event_constraint(c, x86_pmu.event_constraints) {
1210                         if ((event->hw.config & c->cmask) == c->code)
1211                                 return c;
1212                 }
1213         }
1214
1215         return &unconstrained;
1216 }
1217
1218 static int x86_event_sched_in(struct perf_event *event,
1219                           struct perf_cpu_context *cpuctx)
1220 {
1221         int ret = 0;
1222
1223         event->state = PERF_EVENT_STATE_ACTIVE;
1224         event->oncpu = smp_processor_id();
1225         event->tstamp_running += event->ctx->time - event->tstamp_stopped;
1226
1227         if (!is_x86_event(event))
1228                 ret = event->pmu->enable(event);
1229
1230         if (!ret && !is_software_event(event))
1231                 cpuctx->active_oncpu++;
1232
1233         if (!ret && event->attr.exclusive)
1234                 cpuctx->exclusive = 1;
1235
1236         return ret;
1237 }
1238
1239 static void x86_event_sched_out(struct perf_event *event,
1240                             struct perf_cpu_context *cpuctx)
1241 {
1242         event->state = PERF_EVENT_STATE_INACTIVE;
1243         event->oncpu = -1;
1244
1245         if (!is_x86_event(event))
1246                 event->pmu->disable(event);
1247
1248         event->tstamp_running -= event->ctx->time - event->tstamp_stopped;
1249
1250         if (!is_software_event(event))
1251                 cpuctx->active_oncpu--;
1252
1253         if (event->attr.exclusive || !cpuctx->active_oncpu)
1254                 cpuctx->exclusive = 0;
1255 }
1256
1257 /*
1258  * Called to enable a whole group of events.
1259  * Returns 1 if the group was enabled, or -EAGAIN if it could not be.
1260  * Assumes the caller has disabled interrupts and has
1261  * frozen the PMU with hw_perf_save_disable.
1262  *
1263  * called with PMU disabled. If successful and return value 1,
1264  * then guaranteed to call perf_enable() and hw_perf_enable()
1265  */
1266 int hw_perf_group_sched_in(struct perf_event *leader,
1267                struct perf_cpu_context *cpuctx,
1268                struct perf_event_context *ctx)
1269 {
1270         struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
1271         struct perf_event *sub;
1272         int assign[X86_PMC_IDX_MAX];
1273         int n0, n1, ret;
1274
1275         /* n0 = total number of events */
1276         n0 = collect_events(cpuc, leader, true);
1277         if (n0 < 0)
1278                 return n0;
1279
1280         ret = x86_schedule_events(cpuc, n0, assign);
1281         if (ret)
1282                 return ret;
1283
1284         ret = x86_event_sched_in(leader, cpuctx);
1285         if (ret)
1286                 return ret;
1287
1288         n1 = 1;
1289         list_for_each_entry(sub, &leader->sibling_list, group_entry) {
1290                 if (sub->state > PERF_EVENT_STATE_OFF) {
1291                         ret = x86_event_sched_in(sub, cpuctx);
1292                         if (ret)
1293                                 goto undo;
1294                         ++n1;
1295                 }
1296         }
1297         /*
1298          * copy new assignment, now we know it is possible
1299          * will be used by hw_perf_enable()
1300          */
1301         memcpy(cpuc->assign, assign, n0*sizeof(int));
1302
1303         cpuc->n_events  = n0;
1304         cpuc->n_added  += n1;
1305         ctx->nr_active += n1;
1306
1307         /*
1308          * 1 means successful and events are active
1309          * This is not quite true because we defer
1310          * actual activation until hw_perf_enable() but
1311          * this way we* ensure caller won't try to enable
1312          * individual events
1313          */
1314         return 1;
1315 undo:
1316         x86_event_sched_out(leader, cpuctx);
1317         n0  = 1;
1318         list_for_each_entry(sub, &leader->sibling_list, group_entry) {
1319                 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
1320                         x86_event_sched_out(sub, cpuctx);
1321                         if (++n0 == n1)
1322                                 break;
1323                 }
1324         }
1325         return ret;
1326 }
1327
1328 #include "perf_event_amd.c"
1329 #include "perf_event_p6.c"
1330 #include "perf_event_intel.c"
1331
1332 static int __cpuinit
1333 x86_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu)
1334 {
1335         unsigned int cpu = (long)hcpu;
1336
1337         switch (action & ~CPU_TASKS_FROZEN) {
1338         case CPU_UP_PREPARE:
1339                 if (x86_pmu.cpu_prepare)
1340                         x86_pmu.cpu_prepare(cpu);
1341                 break;
1342
1343         case CPU_STARTING:
1344                 if (x86_pmu.cpu_starting)
1345                         x86_pmu.cpu_starting(cpu);
1346                 break;
1347
1348         case CPU_DYING:
1349                 if (x86_pmu.cpu_dying)
1350                         x86_pmu.cpu_dying(cpu);
1351                 break;
1352
1353         case CPU_DEAD:
1354                 if (x86_pmu.cpu_dead)
1355                         x86_pmu.cpu_dead(cpu);
1356                 break;
1357
1358         default:
1359                 break;
1360         }
1361
1362         return NOTIFY_OK;
1363 }
1364
1365 static void __init pmu_check_apic(void)
1366 {
1367         if (cpu_has_apic)
1368                 return;
1369
1370         x86_pmu.apic = 0;
1371         pr_info("no APIC, boot with the \"lapic\" boot parameter to force-enable it.\n");
1372         pr_info("no hardware sampling interrupt available.\n");
1373 }
1374
1375 void __init init_hw_perf_events(void)
1376 {
1377         struct event_constraint *c;
1378         int err;
1379
1380         pr_info("Performance Events: ");
1381
1382         switch (boot_cpu_data.x86_vendor) {
1383         case X86_VENDOR_INTEL:
1384                 err = intel_pmu_init();
1385                 break;
1386         case X86_VENDOR_AMD:
1387                 err = amd_pmu_init();
1388                 break;
1389         default:
1390                 return;
1391         }
1392         if (err != 0) {
1393                 pr_cont("no PMU driver, software events only.\n");
1394                 return;
1395         }
1396
1397         pmu_check_apic();
1398
1399         pr_cont("%s PMU driver.\n", x86_pmu.name);
1400
1401         if (x86_pmu.num_events > X86_PMC_MAX_GENERIC) {
1402                 WARN(1, KERN_ERR "hw perf events %d > max(%d), clipping!",
1403                      x86_pmu.num_events, X86_PMC_MAX_GENERIC);
1404                 x86_pmu.num_events = X86_PMC_MAX_GENERIC;
1405         }
1406         perf_event_mask = (1 << x86_pmu.num_events) - 1;
1407         perf_max_events = x86_pmu.num_events;
1408
1409         if (x86_pmu.num_events_fixed > X86_PMC_MAX_FIXED) {
1410                 WARN(1, KERN_ERR "hw perf events fixed %d > max(%d), clipping!",
1411                      x86_pmu.num_events_fixed, X86_PMC_MAX_FIXED);
1412                 x86_pmu.num_events_fixed = X86_PMC_MAX_FIXED;
1413         }
1414
1415         perf_event_mask |=
1416                 ((1LL << x86_pmu.num_events_fixed)-1) << X86_PMC_IDX_FIXED;
1417         x86_pmu.intel_ctrl = perf_event_mask;
1418
1419         perf_events_lapic_init();
1420         register_die_notifier(&perf_event_nmi_notifier);
1421
1422         unconstrained = (struct event_constraint)
1423                 __EVENT_CONSTRAINT(0, (1ULL << x86_pmu.num_events) - 1,
1424                                    0, x86_pmu.num_events);
1425
1426         if (x86_pmu.event_constraints) {
1427                 for_each_event_constraint(c, x86_pmu.event_constraints) {
1428                         if (c->cmask != INTEL_ARCH_FIXED_MASK)
1429                                 continue;
1430
1431                         c->idxmsk64 |= (1ULL << x86_pmu.num_events) - 1;
1432                         c->weight += x86_pmu.num_events;
1433                 }
1434         }
1435
1436         pr_info("... version:                %d\n",     x86_pmu.version);
1437         pr_info("... bit width:              %d\n",     x86_pmu.event_bits);
1438         pr_info("... generic registers:      %d\n",     x86_pmu.num_events);
1439         pr_info("... value mask:             %016Lx\n", x86_pmu.event_mask);
1440         pr_info("... max period:             %016Lx\n", x86_pmu.max_period);
1441         pr_info("... fixed-purpose events:   %d\n",     x86_pmu.num_events_fixed);
1442         pr_info("... event mask:             %016Lx\n", perf_event_mask);
1443
1444         perf_cpu_notifier(x86_pmu_notifier);
1445 }
1446
1447 static inline void x86_pmu_read(struct perf_event *event)
1448 {
1449         x86_perf_event_update(event);
1450 }
1451
1452 static const struct pmu pmu = {
1453         .enable         = x86_pmu_enable,
1454         .disable        = x86_pmu_disable,
1455         .start          = x86_pmu_start,
1456         .stop           = x86_pmu_stop,
1457         .read           = x86_pmu_read,
1458         .unthrottle     = x86_pmu_unthrottle,
1459 };
1460
1461 /*
1462  * validate a single event group
1463  *
1464  * validation include:
1465  *      - check events are compatible which each other
1466  *      - events do not compete for the same counter
1467  *      - number of events <= number of counters
1468  *
1469  * validation ensures the group can be loaded onto the
1470  * PMU if it was the only group available.
1471  */
1472 static int validate_group(struct perf_event *event)
1473 {
1474         struct perf_event *leader = event->group_leader;
1475         struct cpu_hw_events *fake_cpuc;
1476         int ret, n;
1477
1478         ret = -ENOMEM;
1479         fake_cpuc = kmalloc(sizeof(*fake_cpuc), GFP_KERNEL | __GFP_ZERO);
1480         if (!fake_cpuc)
1481                 goto out;
1482
1483         /*
1484          * the event is not yet connected with its
1485          * siblings therefore we must first collect
1486          * existing siblings, then add the new event
1487          * before we can simulate the scheduling
1488          */
1489         ret = -ENOSPC;
1490         n = collect_events(fake_cpuc, leader, true);
1491         if (n < 0)
1492                 goto out_free;
1493
1494         fake_cpuc->n_events = n;
1495         n = collect_events(fake_cpuc, event, false);
1496         if (n < 0)
1497                 goto out_free;
1498
1499         fake_cpuc->n_events = n;
1500
1501         ret = x86_schedule_events(fake_cpuc, n, NULL);
1502
1503 out_free:
1504         kfree(fake_cpuc);
1505 out:
1506         return ret;
1507 }
1508
1509 const struct pmu *hw_perf_event_init(struct perf_event *event)
1510 {
1511         const struct pmu *tmp;
1512         int err;
1513
1514         err = __hw_perf_event_init(event);
1515         if (!err) {
1516                 /*
1517                  * we temporarily connect event to its pmu
1518                  * such that validate_group() can classify
1519                  * it as an x86 event using is_x86_event()
1520                  */
1521                 tmp = event->pmu;
1522                 event->pmu = &pmu;
1523
1524                 if (event->group_leader != event)
1525                         err = validate_group(event);
1526
1527                 event->pmu = tmp;
1528         }
1529         if (err) {
1530                 if (event->destroy)
1531                         event->destroy(event);
1532                 return ERR_PTR(err);
1533         }
1534
1535         return &pmu;
1536 }
1537
1538 /*
1539  * callchain support
1540  */
1541
1542 static inline
1543 void callchain_store(struct perf_callchain_entry *entry, u64 ip)
1544 {
1545         if (entry->nr < PERF_MAX_STACK_DEPTH)
1546                 entry->ip[entry->nr++] = ip;
1547 }
1548
1549 static DEFINE_PER_CPU(struct perf_callchain_entry, pmc_irq_entry);
1550 static DEFINE_PER_CPU(struct perf_callchain_entry, pmc_nmi_entry);
1551
1552
1553 static void
1554 backtrace_warning_symbol(void *data, char *msg, unsigned long symbol)
1555 {
1556         /* Ignore warnings */
1557 }
1558
1559 static void backtrace_warning(void *data, char *msg)
1560 {
1561         /* Ignore warnings */
1562 }
1563
1564 static int backtrace_stack(void *data, char *name)
1565 {
1566         return 0;
1567 }
1568
1569 static void backtrace_address(void *data, unsigned long addr, int reliable)
1570 {
1571         struct perf_callchain_entry *entry = data;
1572
1573         if (reliable)
1574                 callchain_store(entry, addr);
1575 }
1576
1577 static const struct stacktrace_ops backtrace_ops = {
1578         .warning                = backtrace_warning,
1579         .warning_symbol         = backtrace_warning_symbol,
1580         .stack                  = backtrace_stack,
1581         .address                = backtrace_address,
1582         .walk_stack             = print_context_stack_bp,
1583 };
1584
1585 #include "../dumpstack.h"
1586
1587 static void
1588 perf_callchain_kernel(struct pt_regs *regs, struct perf_callchain_entry *entry)
1589 {
1590         callchain_store(entry, PERF_CONTEXT_KERNEL);
1591         callchain_store(entry, regs->ip);
1592
1593         dump_trace(NULL, regs, NULL, regs->bp, &backtrace_ops, entry);
1594 }
1595
1596 /*
1597  * best effort, GUP based copy_from_user() that assumes IRQ or NMI context
1598  */
1599 static unsigned long
1600 copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
1601 {
1602         unsigned long offset, addr = (unsigned long)from;
1603         int type = in_nmi() ? KM_NMI : KM_IRQ0;
1604         unsigned long size, len = 0;
1605         struct page *page;
1606         void *map;
1607         int ret;
1608
1609         do {
1610                 ret = __get_user_pages_fast(addr, 1, 0, &page);
1611                 if (!ret)
1612                         break;
1613
1614                 offset = addr & (PAGE_SIZE - 1);
1615                 size = min(PAGE_SIZE - offset, n - len);
1616
1617                 map = kmap_atomic(page, type);
1618                 memcpy(to, map+offset, size);
1619                 kunmap_atomic(map, type);
1620                 put_page(page);
1621
1622                 len  += size;
1623                 to   += size;
1624                 addr += size;
1625
1626         } while (len < n);
1627
1628         return len;
1629 }
1630
1631 static int copy_stack_frame(const void __user *fp, struct stack_frame *frame)
1632 {
1633         unsigned long bytes;
1634
1635         bytes = copy_from_user_nmi(frame, fp, sizeof(*frame));
1636
1637         return bytes == sizeof(*frame);
1638 }
1639
1640 static void
1641 perf_callchain_user(struct pt_regs *regs, struct perf_callchain_entry *entry)
1642 {
1643         struct stack_frame frame;
1644         const void __user *fp;
1645
1646         if (!user_mode(regs))
1647                 regs = task_pt_regs(current);
1648
1649         fp = (void __user *)regs->bp;
1650
1651         callchain_store(entry, PERF_CONTEXT_USER);
1652         callchain_store(entry, regs->ip);
1653
1654         while (entry->nr < PERF_MAX_STACK_DEPTH) {
1655                 frame.next_frame             = NULL;
1656                 frame.return_address = 0;
1657
1658                 if (!copy_stack_frame(fp, &frame))
1659                         break;
1660
1661                 if ((unsigned long)fp < regs->sp)
1662                         break;
1663
1664                 callchain_store(entry, frame.return_address);
1665                 fp = frame.next_frame;
1666         }
1667 }
1668
1669 static void
1670 perf_do_callchain(struct pt_regs *regs, struct perf_callchain_entry *entry)
1671 {
1672         int is_user;
1673
1674         if (!regs)
1675                 return;
1676
1677         is_user = user_mode(regs);
1678
1679         if (is_user && current->state != TASK_RUNNING)
1680                 return;
1681
1682         if (!is_user)
1683                 perf_callchain_kernel(regs, entry);
1684
1685         if (current->mm)
1686                 perf_callchain_user(regs, entry);
1687 }
1688
1689 struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
1690 {
1691         struct perf_callchain_entry *entry;
1692
1693         if (in_nmi())
1694                 entry = &__get_cpu_var(pmc_nmi_entry);
1695         else
1696                 entry = &__get_cpu_var(pmc_irq_entry);
1697
1698         entry->nr = 0;
1699
1700         perf_do_callchain(regs, entry);
1701
1702         return entry;
1703 }
1704
1705 void perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int skip)
1706 {
1707         regs->ip = ip;
1708         /*
1709          * perf_arch_fetch_caller_regs adds another call, we need to increment
1710          * the skip level
1711          */
1712         regs->bp = rewind_frame_pointer(skip + 1);
1713         regs->cs = __KERNEL_CS;
1714         local_save_flags(regs->flags);
1715 }
1716 EXPORT_SYMBOL_GPL(perf_arch_fetch_caller_regs);