1 /*
2 * Performance event support - Freescale Embedded Performance Monitor
3 *
4 * Copyright 2008-2009 Paul Mackerras, IBM Corporation.
5 * Copyright 2010 Freescale Semiconductor, Inc.
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 */
12 #include <linux/kernel.h>
13 #include <linux/sched.h>
14 #include <linux/perf_event.h>
15 #include <linux/percpu.h>
16 #include <linux/hardirq.h>
17 #include <asm/reg_fsl_emb.h>
18 #include <asm/pmc.h>
19 #include <asm/machdep.h>
20 #include <asm/firmware.h>
21 #include <asm/ptrace.h>
22
23 struct cpu_hw_events {
24 int n_events;
25 int disabled;
26 u8 pmcs_enabled;
27 struct perf_event *event[MAX_HWEVENTS];
28 };
29 static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events);
30
31 static struct fsl_emb_pmu *ppmu;
32
33 /* Number of perf_events counting hardware events */
34 static atomic_t num_events;
35 /* Used to avoid races in calling reserve/release_pmc_hardware */
36 static DEFINE_MUTEX(pmc_reserve_mutex);
37
38 /*
39 * If interrupts were soft-disabled when a PMU interrupt occurs, treat
40 * it as an NMI.
41 */
perf_intr_is_nmi(struct pt_regs * regs)42 static inline int perf_intr_is_nmi(struct pt_regs *regs)
43 {
44 #ifdef __powerpc64__
45 return !regs->softe;
46 #else
47 return 0;
48 #endif
49 }
50
51 static void perf_event_interrupt(struct pt_regs *regs);
52
53 /*
54 * Read one performance monitor counter (PMC).
55 */
read_pmc(int idx)56 static unsigned long read_pmc(int idx)
57 {
58 unsigned long val;
59
60 switch (idx) {
61 case 0:
62 val = mfpmr(PMRN_PMC0);
63 break;
64 case 1:
65 val = mfpmr(PMRN_PMC1);
66 break;
67 case 2:
68 val = mfpmr(PMRN_PMC2);
69 break;
70 case 3:
71 val = mfpmr(PMRN_PMC3);
72 break;
73 case 4:
74 val = mfpmr(PMRN_PMC4);
75 break;
76 case 5:
77 val = mfpmr(PMRN_PMC5);
78 break;
79 default:
80 printk(KERN_ERR "oops trying to read PMC%d\n", idx);
81 val = 0;
82 }
83 return val;
84 }
85
86 /*
87 * Write one PMC.
88 */
write_pmc(int idx,unsigned long val)89 static void write_pmc(int idx, unsigned long val)
90 {
91 switch (idx) {
92 case 0:
93 mtpmr(PMRN_PMC0, val);
94 break;
95 case 1:
96 mtpmr(PMRN_PMC1, val);
97 break;
98 case 2:
99 mtpmr(PMRN_PMC2, val);
100 break;
101 case 3:
102 mtpmr(PMRN_PMC3, val);
103 break;
104 case 4:
105 mtpmr(PMRN_PMC4, val);
106 break;
107 case 5:
108 mtpmr(PMRN_PMC5, val);
109 break;
110 default:
111 printk(KERN_ERR "oops trying to write PMC%d\n", idx);
112 }
113
114 isync();
115 }
116
117 /*
118 * Write one local control A register
119 */
write_pmlca(int idx,unsigned long val)120 static void write_pmlca(int idx, unsigned long val)
121 {
122 switch (idx) {
123 case 0:
124 mtpmr(PMRN_PMLCA0, val);
125 break;
126 case 1:
127 mtpmr(PMRN_PMLCA1, val);
128 break;
129 case 2:
130 mtpmr(PMRN_PMLCA2, val);
131 break;
132 case 3:
133 mtpmr(PMRN_PMLCA3, val);
134 break;
135 case 4:
136 mtpmr(PMRN_PMLCA4, val);
137 break;
138 case 5:
139 mtpmr(PMRN_PMLCA5, val);
140 break;
141 default:
142 printk(KERN_ERR "oops trying to write PMLCA%d\n", idx);
143 }
144
145 isync();
146 }
147
148 /*
149 * Write one local control B register
150 */
write_pmlcb(int idx,unsigned long val)151 static void write_pmlcb(int idx, unsigned long val)
152 {
153 switch (idx) {
154 case 0:
155 mtpmr(PMRN_PMLCB0, val);
156 break;
157 case 1:
158 mtpmr(PMRN_PMLCB1, val);
159 break;
160 case 2:
161 mtpmr(PMRN_PMLCB2, val);
162 break;
163 case 3:
164 mtpmr(PMRN_PMLCB3, val);
165 break;
166 case 4:
167 mtpmr(PMRN_PMLCB4, val);
168 break;
169 case 5:
170 mtpmr(PMRN_PMLCB5, val);
171 break;
172 default:
173 printk(KERN_ERR "oops trying to write PMLCB%d\n", idx);
174 }
175
176 isync();
177 }
178
fsl_emb_pmu_read(struct perf_event * event)179 static void fsl_emb_pmu_read(struct perf_event *event)
180 {
181 s64 val, delta, prev;
182
183 if (event->hw.state & PERF_HES_STOPPED)
184 return;
185
186 /*
187 * Performance monitor interrupts come even when interrupts
188 * are soft-disabled, as long as interrupts are hard-enabled.
189 * Therefore we treat them like NMIs.
190 */
191 do {
192 prev = local64_read(&event->hw.prev_count);
193 barrier();
194 val = read_pmc(event->hw.idx);
195 } while (local64_cmpxchg(&event->hw.prev_count, prev, val) != prev);
196
197 /* The counters are only 32 bits wide */
198 delta = (val - prev) & 0xfffffffful;
199 local64_add(delta, &event->count);
200 local64_sub(delta, &event->hw.period_left);
201 }
202
203 /*
204 * Disable all events to prevent PMU interrupts and to allow
205 * events to be added or removed.
206 */
fsl_emb_pmu_disable(struct pmu * pmu)207 static void fsl_emb_pmu_disable(struct pmu *pmu)
208 {
209 struct cpu_hw_events *cpuhw;
210 unsigned long flags;
211
212 local_irq_save(flags);
213 cpuhw = this_cpu_ptr(&cpu_hw_events);
214
215 if (!cpuhw->disabled) {
216 cpuhw->disabled = 1;
217
218 /*
219 * Check if we ever enabled the PMU on this cpu.
220 */
221 if (!cpuhw->pmcs_enabled) {
222 ppc_enable_pmcs();
223 cpuhw->pmcs_enabled = 1;
224 }
225
226 if (atomic_read(&num_events)) {
227 /*
228 * Set the 'freeze all counters' bit, and disable
229 * interrupts. The barrier is to make sure the
230 * mtpmr has been executed and the PMU has frozen
231 * the events before we return.
232 */
233
234 mtpmr(PMRN_PMGC0, PMGC0_FAC);
235 isync();
236 }
237 }
238 local_irq_restore(flags);
239 }
240
241 /*
242 * Re-enable all events if disable == 0.
243 * If we were previously disabled and events were added, then
244 * put the new config on the PMU.
245 */
fsl_emb_pmu_enable(struct pmu * pmu)246 static void fsl_emb_pmu_enable(struct pmu *pmu)
247 {
248 struct cpu_hw_events *cpuhw;
249 unsigned long flags;
250
251 local_irq_save(flags);
252 cpuhw = this_cpu_ptr(&cpu_hw_events);
253 if (!cpuhw->disabled)
254 goto out;
255
256 cpuhw->disabled = 0;
257 ppc_set_pmu_inuse(cpuhw->n_events != 0);
258
259 if (cpuhw->n_events > 0) {
260 mtpmr(PMRN_PMGC0, PMGC0_PMIE | PMGC0_FCECE);
261 isync();
262 }
263
264 out:
265 local_irq_restore(flags);
266 }
267
collect_events(struct perf_event * group,int max_count,struct perf_event * ctrs[])268 static int collect_events(struct perf_event *group, int max_count,
269 struct perf_event *ctrs[])
270 {
271 int n = 0;
272 struct perf_event *event;
273
274 if (!is_software_event(group)) {
275 if (n >= max_count)
276 return -1;
277 ctrs[n] = group;
278 n++;
279 }
280 list_for_each_entry(event, &group->sibling_list, group_entry) {
281 if (!is_software_event(event) &&
282 event->state != PERF_EVENT_STATE_OFF) {
283 if (n >= max_count)
284 return -1;
285 ctrs[n] = event;
286 n++;
287 }
288 }
289 return n;
290 }
291
292 /* context locked on entry */
fsl_emb_pmu_add(struct perf_event * event,int flags)293 static int fsl_emb_pmu_add(struct perf_event *event, int flags)
294 {
295 struct cpu_hw_events *cpuhw;
296 int ret = -EAGAIN;
297 int num_counters = ppmu->n_counter;
298 u64 val;
299 int i;
300
301 perf_pmu_disable(event->pmu);
302 cpuhw = &get_cpu_var(cpu_hw_events);
303
304 if (event->hw.config & FSL_EMB_EVENT_RESTRICTED)
305 num_counters = ppmu->n_restricted;
306
307 /*
308 * Allocate counters from top-down, so that restricted-capable
309 * counters are kept free as long as possible.
310 */
311 for (i = num_counters - 1; i >= 0; i--) {
312 if (cpuhw->event[i])
313 continue;
314
315 break;
316 }
317
318 if (i < 0)
319 goto out;
320
321 event->hw.idx = i;
322 cpuhw->event[i] = event;
323 ++cpuhw->n_events;
324
325 val = 0;
326 if (event->hw.sample_period) {
327 s64 left = local64_read(&event->hw.period_left);
328 if (left < 0x80000000L)
329 val = 0x80000000L - left;
330 }
331 local64_set(&event->hw.prev_count, val);
332
333 if (unlikely(!(flags & PERF_EF_START))) {
334 event->hw.state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
335 val = 0;
336 } else {
337 event->hw.state &= ~(PERF_HES_STOPPED | PERF_HES_UPTODATE);
338 }
339
340 write_pmc(i, val);
341 perf_event_update_userpage(event);
342
343 write_pmlcb(i, event->hw.config >> 32);
344 write_pmlca(i, event->hw.config_base);
345
346 ret = 0;
347 out:
348 put_cpu_var(cpu_hw_events);
349 perf_pmu_enable(event->pmu);
350 return ret;
351 }
352
353 /* context locked on entry */
fsl_emb_pmu_del(struct perf_event * event,int flags)354 static void fsl_emb_pmu_del(struct perf_event *event, int flags)
355 {
356 struct cpu_hw_events *cpuhw;
357 int i = event->hw.idx;
358
359 perf_pmu_disable(event->pmu);
360 if (i < 0)
361 goto out;
362
363 fsl_emb_pmu_read(event);
364
365 cpuhw = &get_cpu_var(cpu_hw_events);
366
367 WARN_ON(event != cpuhw->event[event->hw.idx]);
368
369 write_pmlca(i, 0);
370 write_pmlcb(i, 0);
371 write_pmc(i, 0);
372
373 cpuhw->event[i] = NULL;
374 event->hw.idx = -1;
375
376 /*
377 * TODO: if at least one restricted event exists, and we
378 * just freed up a non-restricted-capable counter, and
379 * there is a restricted-capable counter occupied by
380 * a non-restricted event, migrate that event to the
381 * vacated counter.
382 */
383
384 cpuhw->n_events--;
385
386 out:
387 perf_pmu_enable(event->pmu);
388 put_cpu_var(cpu_hw_events);
389 }
390
fsl_emb_pmu_start(struct perf_event * event,int ef_flags)391 static void fsl_emb_pmu_start(struct perf_event *event, int ef_flags)
392 {
393 unsigned long flags;
394 unsigned long val;
395 s64 left;
396
397 if (event->hw.idx < 0 || !event->hw.sample_period)
398 return;
399
400 if (!(event->hw.state & PERF_HES_STOPPED))
401 return;
402
403 if (ef_flags & PERF_EF_RELOAD)
404 WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE));
405
406 local_irq_save(flags);
407 perf_pmu_disable(event->pmu);
408
409 event->hw.state = 0;
410 left = local64_read(&event->hw.period_left);
411 val = 0;
412 if (left < 0x80000000L)
413 val = 0x80000000L - left;
414 write_pmc(event->hw.idx, val);
415
416 perf_event_update_userpage(event);
417 perf_pmu_enable(event->pmu);
418 local_irq_restore(flags);
419 }
420
fsl_emb_pmu_stop(struct perf_event * event,int ef_flags)421 static void fsl_emb_pmu_stop(struct perf_event *event, int ef_flags)
422 {
423 unsigned long flags;
424
425 if (event->hw.idx < 0 || !event->hw.sample_period)
426 return;
427
428 if (event->hw.state & PERF_HES_STOPPED)
429 return;
430
431 local_irq_save(flags);
432 perf_pmu_disable(event->pmu);
433
434 fsl_emb_pmu_read(event);
435 event->hw.state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
436 write_pmc(event->hw.idx, 0);
437
438 perf_event_update_userpage(event);
439 perf_pmu_enable(event->pmu);
440 local_irq_restore(flags);
441 }
442
443 /*
444 * Release the PMU if this is the last perf_event.
445 */
hw_perf_event_destroy(struct perf_event * event)446 static void hw_perf_event_destroy(struct perf_event *event)
447 {
448 if (!atomic_add_unless(&num_events, -1, 1)) {
449 mutex_lock(&pmc_reserve_mutex);
450 if (atomic_dec_return(&num_events) == 0)
451 release_pmc_hardware();
452 mutex_unlock(&pmc_reserve_mutex);
453 }
454 }
455
456 /*
457 * Translate a generic cache event_id config to a raw event_id code.
458 */
hw_perf_cache_event(u64 config,u64 * eventp)459 static int hw_perf_cache_event(u64 config, u64 *eventp)
460 {
461 unsigned long type, op, result;
462 int ev;
463
464 if (!ppmu->cache_events)
465 return -EINVAL;
466
467 /* unpack config */
468 type = config & 0xff;
469 op = (config >> 8) & 0xff;
470 result = (config >> 16) & 0xff;
471
472 if (type >= PERF_COUNT_HW_CACHE_MAX ||
473 op >= PERF_COUNT_HW_CACHE_OP_MAX ||
474 result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
475 return -EINVAL;
476
477 ev = (*ppmu->cache_events)[type][op][result];
478 if (ev == 0)
479 return -EOPNOTSUPP;
480 if (ev == -1)
481 return -EINVAL;
482 *eventp = ev;
483 return 0;
484 }
485
fsl_emb_pmu_event_init(struct perf_event * event)486 static int fsl_emb_pmu_event_init(struct perf_event *event)
487 {
488 u64 ev;
489 struct perf_event *events[MAX_HWEVENTS];
490 int n;
491 int err;
492 int num_restricted;
493 int i;
494
495 if (ppmu->n_counter > MAX_HWEVENTS) {
496 WARN(1, "No. of perf counters (%d) is higher than max array size(%d)\n",
497 ppmu->n_counter, MAX_HWEVENTS);
498 ppmu->n_counter = MAX_HWEVENTS;
499 }
500
501 switch (event->attr.type) {
502 case PERF_TYPE_HARDWARE:
503 ev = event->attr.config;
504 if (ev >= ppmu->n_generic || ppmu->generic_events[ev] == 0)
505 return -EOPNOTSUPP;
506 ev = ppmu->generic_events[ev];
507 break;
508
509 case PERF_TYPE_HW_CACHE:
510 err = hw_perf_cache_event(event->attr.config, &ev);
511 if (err)
512 return err;
513 break;
514
515 case PERF_TYPE_RAW:
516 ev = event->attr.config;
517 break;
518
519 default:
520 return -ENOENT;
521 }
522
523 event->hw.config = ppmu->xlate_event(ev);
524 if (!(event->hw.config & FSL_EMB_EVENT_VALID))
525 return -EINVAL;
526
527 /*
528 * If this is in a group, check if it can go on with all the
529 * other hardware events in the group. We assume the event
530 * hasn't been linked into its leader's sibling list at this point.
531 */
532 n = 0;
533 if (event->group_leader != event) {
534 n = collect_events(event->group_leader,
535 ppmu->n_counter - 1, events);
536 if (n < 0)
537 return -EINVAL;
538 }
539
540 if (event->hw.config & FSL_EMB_EVENT_RESTRICTED) {
541 num_restricted = 0;
542 for (i = 0; i < n; i++) {
543 if (events[i]->hw.config & FSL_EMB_EVENT_RESTRICTED)
544 num_restricted++;
545 }
546
547 if (num_restricted >= ppmu->n_restricted)
548 return -EINVAL;
549 }
550
551 event->hw.idx = -1;
552
553 event->hw.config_base = PMLCA_CE | PMLCA_FCM1 |
554 (u32)((ev << 16) & PMLCA_EVENT_MASK);
555
556 if (event->attr.exclude_user)
557 event->hw.config_base |= PMLCA_FCU;
558 if (event->attr.exclude_kernel)
559 event->hw.config_base |= PMLCA_FCS;
560 if (event->attr.exclude_idle)
561 return -ENOTSUPP;
562
563 event->hw.last_period = event->hw.sample_period;
564 local64_set(&event->hw.period_left, event->hw.last_period);
565
566 /*
567 * See if we need to reserve the PMU.
568 * If no events are currently in use, then we have to take a
569 * mutex to ensure that we don't race with another task doing
570 * reserve_pmc_hardware or release_pmc_hardware.
571 */
572 err = 0;
573 if (!atomic_inc_not_zero(&num_events)) {
574 mutex_lock(&pmc_reserve_mutex);
575 if (atomic_read(&num_events) == 0 &&
576 reserve_pmc_hardware(perf_event_interrupt))
577 err = -EBUSY;
578 else
579 atomic_inc(&num_events);
580 mutex_unlock(&pmc_reserve_mutex);
581
582 mtpmr(PMRN_PMGC0, PMGC0_FAC);
583 isync();
584 }
585 event->destroy = hw_perf_event_destroy;
586
587 return err;
588 }
589
590 static struct pmu fsl_emb_pmu = {
591 .pmu_enable = fsl_emb_pmu_enable,
592 .pmu_disable = fsl_emb_pmu_disable,
593 .event_init = fsl_emb_pmu_event_init,
594 .add = fsl_emb_pmu_add,
595 .del = fsl_emb_pmu_del,
596 .start = fsl_emb_pmu_start,
597 .stop = fsl_emb_pmu_stop,
598 .read = fsl_emb_pmu_read,
599 };
600
601 /*
602 * A counter has overflowed; update its count and record
603 * things if requested. Note that interrupts are hard-disabled
604 * here so there is no possibility of being interrupted.
605 */
record_and_restart(struct perf_event * event,unsigned long val,struct pt_regs * regs)606 static void record_and_restart(struct perf_event *event, unsigned long val,
607 struct pt_regs *regs)
608 {
609 u64 period = event->hw.sample_period;
610 s64 prev, delta, left;
611 int record = 0;
612
613 if (event->hw.state & PERF_HES_STOPPED) {
614 write_pmc(event->hw.idx, 0);
615 return;
616 }
617
618 /* we don't have to worry about interrupts here */
619 prev = local64_read(&event->hw.prev_count);
620 delta = (val - prev) & 0xfffffffful;
621 local64_add(delta, &event->count);
622
623 /*
624 * See if the total period for this event has expired,
625 * and update for the next period.
626 */
627 val = 0;
628 left = local64_read(&event->hw.period_left) - delta;
629 if (period) {
630 if (left <= 0) {
631 left += period;
632 if (left <= 0)
633 left = period;
634 record = 1;
635 event->hw.last_period = event->hw.sample_period;
636 }
637 if (left < 0x80000000LL)
638 val = 0x80000000LL - left;
639 }
640
641 write_pmc(event->hw.idx, val);
642 local64_set(&event->hw.prev_count, val);
643 local64_set(&event->hw.period_left, left);
644 perf_event_update_userpage(event);
645
646 /*
647 * Finally record data if requested.
648 */
649 if (record) {
650 struct perf_sample_data data;
651
652 perf_sample_data_init(&data, 0, event->hw.last_period);
653
654 if (perf_event_overflow(event, &data, regs))
655 fsl_emb_pmu_stop(event, 0);
656 }
657 }
658
perf_event_interrupt(struct pt_regs * regs)659 static void perf_event_interrupt(struct pt_regs *regs)
660 {
661 int i;
662 struct cpu_hw_events *cpuhw = this_cpu_ptr(&cpu_hw_events);
663 struct perf_event *event;
664 unsigned long val;
665 int found = 0;
666 int nmi;
667
668 nmi = perf_intr_is_nmi(regs);
669 if (nmi)
670 nmi_enter();
671 else
672 irq_enter();
673
674 for (i = 0; i < ppmu->n_counter; ++i) {
675 event = cpuhw->event[i];
676
677 val = read_pmc(i);
678 if ((int)val < 0) {
679 if (event) {
680 /* event has overflowed */
681 found = 1;
682 record_and_restart(event, val, regs);
683 } else {
684 /*
685 * Disabled counter is negative,
686 * reset it just in case.
687 */
688 write_pmc(i, 0);
689 }
690 }
691 }
692
693 /* PMM will keep counters frozen until we return from the interrupt. */
694 mtmsr(mfmsr() | MSR_PMM);
695 mtpmr(PMRN_PMGC0, PMGC0_PMIE | PMGC0_FCECE);
696 isync();
697
698 if (nmi)
699 nmi_exit();
700 else
701 irq_exit();
702 }
703
hw_perf_event_setup(int cpu)704 void hw_perf_event_setup(int cpu)
705 {
706 struct cpu_hw_events *cpuhw = &per_cpu(cpu_hw_events, cpu);
707
708 memset(cpuhw, 0, sizeof(*cpuhw));
709 }
710
register_fsl_emb_pmu(struct fsl_emb_pmu * pmu)711 int register_fsl_emb_pmu(struct fsl_emb_pmu *pmu)
712 {
713 if (ppmu)
714 return -EBUSY; /* something's already registered */
715
716 ppmu = pmu;
717 pr_info("%s performance monitor hardware support registered\n",
718 pmu->name);
719
720 perf_pmu_register(&fsl_emb_pmu, "cpu", PERF_TYPE_RAW);
721
722 return 0;
723 }
724