Merge branch 'depends/rmk/devel-stable' into next/boards
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / arch / arm / kernel / perf_event.c
bloba4f192cc51b23b3d75935a0e550c7f8a4cd6b12d
1 #undef DEBUG
3 /*
4 * ARM performance counter support.
6 * Copyright (C) 2009 picoChip Designs, Ltd., Jamie Iles
7 * Copyright (C) 2010 ARM Ltd., Will Deacon <will.deacon@arm.com>
9 * This code is based on the sparc64 perf event code, which is in turn based
10 * on the x86 code. Callchain code is based on the ARM OProfile backtrace
11 * code.
13 #define pr_fmt(fmt) "hw perfevents: " fmt
15 #include <linux/bitmap.h>
16 #include <linux/interrupt.h>
17 #include <linux/kernel.h>
18 #include <linux/export.h>
19 #include <linux/perf_event.h>
20 #include <linux/platform_device.h>
21 #include <linux/spinlock.h>
22 #include <linux/uaccess.h>
24 #include <asm/cputype.h>
25 #include <asm/irq.h>
26 #include <asm/irq_regs.h>
27 #include <asm/pmu.h>
28 #include <asm/stacktrace.h>
31 * ARMv6 supports a maximum of 3 events, starting from index 0. If we add
32 * another platform that supports more, we need to increase this to be the
33 * largest of all platforms.
35 * ARMv7 supports up to 32 events:
36 * cycle counter CCNT + 31 events counters CNT0..30.
37 * Cortex-A8 has 1+4 counters, Cortex-A9 has 1+6 counters.
39 #define ARMPMU_MAX_HWEVENTS 32
41 static DEFINE_PER_CPU(struct perf_event * [ARMPMU_MAX_HWEVENTS], hw_events);
42 static DEFINE_PER_CPU(unsigned long [BITS_TO_LONGS(ARMPMU_MAX_HWEVENTS)], used_mask);
43 static DEFINE_PER_CPU(struct pmu_hw_events, cpu_hw_events);
45 #define to_arm_pmu(p) (container_of(p, struct arm_pmu, pmu))
47 /* Set at runtime when we know what CPU type we are. */
48 static struct arm_pmu *cpu_pmu;
50 enum arm_perf_pmu_ids
51 armpmu_get_pmu_id(void)
53 int id = -ENODEV;
55 if (cpu_pmu != NULL)
56 id = cpu_pmu->id;
58 return id;
60 EXPORT_SYMBOL_GPL(armpmu_get_pmu_id);
62 int perf_num_counters(void)
64 int max_events = 0;
66 if (cpu_pmu != NULL)
67 max_events = cpu_pmu->num_events;
69 return max_events;
71 EXPORT_SYMBOL_GPL(perf_num_counters);
73 #define HW_OP_UNSUPPORTED 0xFFFF
75 #define C(_x) \
76 PERF_COUNT_HW_CACHE_##_x
78 #define CACHE_OP_UNSUPPORTED 0xFFFF
80 static int
81 armpmu_map_cache_event(const unsigned (*cache_map)
82 [PERF_COUNT_HW_CACHE_MAX]
83 [PERF_COUNT_HW_CACHE_OP_MAX]
84 [PERF_COUNT_HW_CACHE_RESULT_MAX],
85 u64 config)
87 unsigned int cache_type, cache_op, cache_result, ret;
89 cache_type = (config >> 0) & 0xff;
90 if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
91 return -EINVAL;
93 cache_op = (config >> 8) & 0xff;
94 if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
95 return -EINVAL;
97 cache_result = (config >> 16) & 0xff;
98 if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
99 return -EINVAL;
101 ret = (int)(*cache_map)[cache_type][cache_op][cache_result];
103 if (ret == CACHE_OP_UNSUPPORTED)
104 return -ENOENT;
106 return ret;
109 static int
110 armpmu_map_event(const unsigned (*event_map)[PERF_COUNT_HW_MAX], u64 config)
112 int mapping = (*event_map)[config];
113 return mapping == HW_OP_UNSUPPORTED ? -ENOENT : mapping;
116 static int
117 armpmu_map_raw_event(u32 raw_event_mask, u64 config)
119 return (int)(config & raw_event_mask);
122 static int map_cpu_event(struct perf_event *event,
123 const unsigned (*event_map)[PERF_COUNT_HW_MAX],
124 const unsigned (*cache_map)
125 [PERF_COUNT_HW_CACHE_MAX]
126 [PERF_COUNT_HW_CACHE_OP_MAX]
127 [PERF_COUNT_HW_CACHE_RESULT_MAX],
128 u32 raw_event_mask)
130 u64 config = event->attr.config;
132 switch (event->attr.type) {
133 case PERF_TYPE_HARDWARE:
134 return armpmu_map_event(event_map, config);
135 case PERF_TYPE_HW_CACHE:
136 return armpmu_map_cache_event(cache_map, config);
137 case PERF_TYPE_RAW:
138 return armpmu_map_raw_event(raw_event_mask, config);
141 return -ENOENT;
145 armpmu_event_set_period(struct perf_event *event,
146 struct hw_perf_event *hwc,
147 int idx)
149 struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
150 s64 left = local64_read(&hwc->period_left);
151 s64 period = hwc->sample_period;
152 int ret = 0;
154 if (unlikely(left <= -period)) {
155 left = period;
156 local64_set(&hwc->period_left, left);
157 hwc->last_period = period;
158 ret = 1;
161 if (unlikely(left <= 0)) {
162 left += period;
163 local64_set(&hwc->period_left, left);
164 hwc->last_period = period;
165 ret = 1;
168 if (left > (s64)armpmu->max_period)
169 left = armpmu->max_period;
171 local64_set(&hwc->prev_count, (u64)-left);
173 armpmu->write_counter(idx, (u64)(-left) & 0xffffffff);
175 perf_event_update_userpage(event);
177 return ret;
181 armpmu_event_update(struct perf_event *event,
182 struct hw_perf_event *hwc,
183 int idx, int overflow)
185 struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
186 u64 delta, prev_raw_count, new_raw_count;
188 again:
189 prev_raw_count = local64_read(&hwc->prev_count);
190 new_raw_count = armpmu->read_counter(idx);
192 if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
193 new_raw_count) != prev_raw_count)
194 goto again;
196 new_raw_count &= armpmu->max_period;
197 prev_raw_count &= armpmu->max_period;
199 if (overflow)
200 delta = armpmu->max_period - prev_raw_count + new_raw_count + 1;
201 else
202 delta = new_raw_count - prev_raw_count;
204 local64_add(delta, &event->count);
205 local64_sub(delta, &hwc->period_left);
207 return new_raw_count;
210 static void
211 armpmu_read(struct perf_event *event)
213 struct hw_perf_event *hwc = &event->hw;
215 /* Don't read disabled counters! */
216 if (hwc->idx < 0)
217 return;
219 armpmu_event_update(event, hwc, hwc->idx, 0);
222 static void
223 armpmu_stop(struct perf_event *event, int flags)
225 struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
226 struct hw_perf_event *hwc = &event->hw;
229 * ARM pmu always has to update the counter, so ignore
230 * PERF_EF_UPDATE, see comments in armpmu_start().
232 if (!(hwc->state & PERF_HES_STOPPED)) {
233 armpmu->disable(hwc, hwc->idx);
234 barrier(); /* why? */
235 armpmu_event_update(event, hwc, hwc->idx, 0);
236 hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
240 static void
241 armpmu_start(struct perf_event *event, int flags)
243 struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
244 struct hw_perf_event *hwc = &event->hw;
247 * ARM pmu always has to reprogram the period, so ignore
248 * PERF_EF_RELOAD, see the comment below.
250 if (flags & PERF_EF_RELOAD)
251 WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
253 hwc->state = 0;
255 * Set the period again. Some counters can't be stopped, so when we
256 * were stopped we simply disabled the IRQ source and the counter
257 * may have been left counting. If we don't do this step then we may
258 * get an interrupt too soon or *way* too late if the overflow has
259 * happened since disabling.
261 armpmu_event_set_period(event, hwc, hwc->idx);
262 armpmu->enable(hwc, hwc->idx);
265 static void
266 armpmu_del(struct perf_event *event, int flags)
268 struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
269 struct pmu_hw_events *hw_events = armpmu->get_hw_events();
270 struct hw_perf_event *hwc = &event->hw;
271 int idx = hwc->idx;
273 WARN_ON(idx < 0);
275 armpmu_stop(event, PERF_EF_UPDATE);
276 hw_events->events[idx] = NULL;
277 clear_bit(idx, hw_events->used_mask);
279 perf_event_update_userpage(event);
282 static int
283 armpmu_add(struct perf_event *event, int flags)
285 struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
286 struct pmu_hw_events *hw_events = armpmu->get_hw_events();
287 struct hw_perf_event *hwc = &event->hw;
288 int idx;
289 int err = 0;
291 perf_pmu_disable(event->pmu);
293 /* If we don't have a space for the counter then finish early. */
294 idx = armpmu->get_event_idx(hw_events, hwc);
295 if (idx < 0) {
296 err = idx;
297 goto out;
301 * If there is an event in the counter we are going to use then make
302 * sure it is disabled.
304 event->hw.idx = idx;
305 armpmu->disable(hwc, idx);
306 hw_events->events[idx] = event;
308 hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
309 if (flags & PERF_EF_START)
310 armpmu_start(event, PERF_EF_RELOAD);
312 /* Propagate our changes to the userspace mapping. */
313 perf_event_update_userpage(event);
315 out:
316 perf_pmu_enable(event->pmu);
317 return err;
320 static int
321 validate_event(struct pmu_hw_events *hw_events,
322 struct perf_event *event)
324 struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
325 struct hw_perf_event fake_event = event->hw;
326 struct pmu *leader_pmu = event->group_leader->pmu;
328 if (event->pmu != leader_pmu || event->state <= PERF_EVENT_STATE_OFF)
329 return 1;
331 return armpmu->get_event_idx(hw_events, &fake_event) >= 0;
334 static int
335 validate_group(struct perf_event *event)
337 struct perf_event *sibling, *leader = event->group_leader;
338 struct pmu_hw_events fake_pmu;
339 DECLARE_BITMAP(fake_used_mask, ARMPMU_MAX_HWEVENTS);
342 * Initialise the fake PMU. We only need to populate the
343 * used_mask for the purposes of validation.
345 memset(fake_used_mask, 0, sizeof(fake_used_mask));
346 fake_pmu.used_mask = fake_used_mask;
348 if (!validate_event(&fake_pmu, leader))
349 return -EINVAL;
351 list_for_each_entry(sibling, &leader->sibling_list, group_entry) {
352 if (!validate_event(&fake_pmu, sibling))
353 return -EINVAL;
356 if (!validate_event(&fake_pmu, event))
357 return -EINVAL;
359 return 0;
362 static irqreturn_t armpmu_platform_irq(int irq, void *dev)
364 struct arm_pmu *armpmu = (struct arm_pmu *) dev;
365 struct platform_device *plat_device = armpmu->plat_device;
366 struct arm_pmu_platdata *plat = dev_get_platdata(&plat_device->dev);
368 return plat->handle_irq(irq, dev, armpmu->handle_irq);
371 static void
372 armpmu_release_hardware(struct arm_pmu *armpmu)
374 int i, irq, irqs;
375 struct platform_device *pmu_device = armpmu->plat_device;
376 struct arm_pmu_platdata *plat =
377 dev_get_platdata(&pmu_device->dev);
379 irqs = min(pmu_device->num_resources, num_possible_cpus());
381 for (i = 0; i < irqs; ++i) {
382 if (!cpumask_test_and_clear_cpu(i, &armpmu->active_irqs))
383 continue;
384 irq = platform_get_irq(pmu_device, i);
385 if (irq >= 0) {
386 if (plat && plat->disable_irq)
387 plat->disable_irq(irq);
388 free_irq(irq, armpmu);
392 release_pmu(armpmu->type);
395 static int
396 armpmu_reserve_hardware(struct arm_pmu *armpmu)
398 struct arm_pmu_platdata *plat;
399 irq_handler_t handle_irq;
400 int i, err, irq, irqs;
401 struct platform_device *pmu_device = armpmu->plat_device;
403 if (!pmu_device)
404 return -ENODEV;
406 err = reserve_pmu(armpmu->type);
407 if (err) {
408 pr_warning("unable to reserve pmu\n");
409 return err;
412 plat = dev_get_platdata(&pmu_device->dev);
413 if (plat && plat->handle_irq)
414 handle_irq = armpmu_platform_irq;
415 else
416 handle_irq = armpmu->handle_irq;
418 irqs = min(pmu_device->num_resources, num_possible_cpus());
419 if (irqs < 1) {
420 pr_err("no irqs for PMUs defined\n");
421 return -ENODEV;
424 for (i = 0; i < irqs; ++i) {
425 err = 0;
426 irq = platform_get_irq(pmu_device, i);
427 if (irq < 0)
428 continue;
431 * If we have a single PMU interrupt that we can't shift,
432 * assume that we're running on a uniprocessor machine and
433 * continue. Otherwise, continue without this interrupt.
435 if (irq_set_affinity(irq, cpumask_of(i)) && irqs > 1) {
436 pr_warning("unable to set irq affinity (irq=%d, cpu=%u)\n",
437 irq, i);
438 continue;
441 err = request_irq(irq, handle_irq,
442 IRQF_DISABLED | IRQF_NOBALANCING,
443 "arm-pmu", armpmu);
444 if (err) {
445 pr_err("unable to request IRQ%d for ARM PMU counters\n",
446 irq);
447 armpmu_release_hardware(armpmu);
448 return err;
449 } else if (plat && plat->enable_irq)
450 plat->enable_irq(irq);
452 cpumask_set_cpu(i, &armpmu->active_irqs);
455 return 0;
458 static void
459 hw_perf_event_destroy(struct perf_event *event)
461 struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
462 atomic_t *active_events = &armpmu->active_events;
463 struct mutex *pmu_reserve_mutex = &armpmu->reserve_mutex;
465 if (atomic_dec_and_mutex_lock(active_events, pmu_reserve_mutex)) {
466 armpmu_release_hardware(armpmu);
467 mutex_unlock(pmu_reserve_mutex);
471 static int
472 event_requires_mode_exclusion(struct perf_event_attr *attr)
474 return attr->exclude_idle || attr->exclude_user ||
475 attr->exclude_kernel || attr->exclude_hv;
478 static int
479 __hw_perf_event_init(struct perf_event *event)
481 struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
482 struct hw_perf_event *hwc = &event->hw;
483 int mapping, err;
485 mapping = armpmu->map_event(event);
487 if (mapping < 0) {
488 pr_debug("event %x:%llx not supported\n", event->attr.type,
489 event->attr.config);
490 return mapping;
494 * We don't assign an index until we actually place the event onto
495 * hardware. Use -1 to signify that we haven't decided where to put it
496 * yet. For SMP systems, each core has it's own PMU so we can't do any
497 * clever allocation or constraints checking at this point.
499 hwc->idx = -1;
500 hwc->config_base = 0;
501 hwc->config = 0;
502 hwc->event_base = 0;
505 * Check whether we need to exclude the counter from certain modes.
507 if ((!armpmu->set_event_filter ||
508 armpmu->set_event_filter(hwc, &event->attr)) &&
509 event_requires_mode_exclusion(&event->attr)) {
510 pr_debug("ARM performance counters do not support "
511 "mode exclusion\n");
512 return -EPERM;
516 * Store the event encoding into the config_base field.
518 hwc->config_base |= (unsigned long)mapping;
520 if (!hwc->sample_period) {
521 hwc->sample_period = armpmu->max_period;
522 hwc->last_period = hwc->sample_period;
523 local64_set(&hwc->period_left, hwc->sample_period);
526 err = 0;
527 if (event->group_leader != event) {
528 err = validate_group(event);
529 if (err)
530 return -EINVAL;
533 return err;
536 static int armpmu_event_init(struct perf_event *event)
538 struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
539 int err = 0;
540 atomic_t *active_events = &armpmu->active_events;
542 if (armpmu->map_event(event) == -ENOENT)
543 return -ENOENT;
545 event->destroy = hw_perf_event_destroy;
547 if (!atomic_inc_not_zero(active_events)) {
548 mutex_lock(&armpmu->reserve_mutex);
549 if (atomic_read(active_events) == 0)
550 err = armpmu_reserve_hardware(armpmu);
552 if (!err)
553 atomic_inc(active_events);
554 mutex_unlock(&armpmu->reserve_mutex);
557 if (err)
558 return err;
560 err = __hw_perf_event_init(event);
561 if (err)
562 hw_perf_event_destroy(event);
564 return err;
567 static void armpmu_enable(struct pmu *pmu)
569 struct arm_pmu *armpmu = to_arm_pmu(pmu);
570 struct pmu_hw_events *hw_events = armpmu->get_hw_events();
571 int enabled = bitmap_weight(hw_events->used_mask, armpmu->num_events);
573 if (enabled)
574 armpmu->start();
577 static void armpmu_disable(struct pmu *pmu)
579 struct arm_pmu *armpmu = to_arm_pmu(pmu);
580 armpmu->stop();
583 static void __init armpmu_init(struct arm_pmu *armpmu)
585 atomic_set(&armpmu->active_events, 0);
586 mutex_init(&armpmu->reserve_mutex);
588 armpmu->pmu = (struct pmu) {
589 .pmu_enable = armpmu_enable,
590 .pmu_disable = armpmu_disable,
591 .event_init = armpmu_event_init,
592 .add = armpmu_add,
593 .del = armpmu_del,
594 .start = armpmu_start,
595 .stop = armpmu_stop,
596 .read = armpmu_read,
600 int __init armpmu_register(struct arm_pmu *armpmu, char *name, int type)
602 armpmu_init(armpmu);
603 return perf_pmu_register(&armpmu->pmu, name, type);
606 /* Include the PMU-specific implementations. */
607 #include "perf_event_xscale.c"
608 #include "perf_event_v6.c"
609 #include "perf_event_v7.c"
612 * Ensure the PMU has sane values out of reset.
613 * This requires SMP to be available, so exists as a separate initcall.
615 static int __init
616 cpu_pmu_reset(void)
618 if (cpu_pmu && cpu_pmu->reset)
619 return on_each_cpu(cpu_pmu->reset, NULL, 1);
620 return 0;
622 arch_initcall(cpu_pmu_reset);
625 * PMU platform driver and devicetree bindings.
627 static struct of_device_id armpmu_of_device_ids[] = {
628 {.compatible = "arm,cortex-a9-pmu"},
629 {.compatible = "arm,cortex-a8-pmu"},
630 {.compatible = "arm,arm1136-pmu"},
631 {.compatible = "arm,arm1176-pmu"},
635 static struct platform_device_id armpmu_plat_device_ids[] = {
636 {.name = "arm-pmu"},
640 static int __devinit armpmu_device_probe(struct platform_device *pdev)
642 cpu_pmu->plat_device = pdev;
643 return 0;
646 static struct platform_driver armpmu_driver = {
647 .driver = {
648 .name = "arm-pmu",
649 .of_match_table = armpmu_of_device_ids,
651 .probe = armpmu_device_probe,
652 .id_table = armpmu_plat_device_ids,
655 static int __init register_pmu_driver(void)
657 return platform_driver_register(&armpmu_driver);
659 device_initcall(register_pmu_driver);
661 static struct pmu_hw_events *armpmu_get_cpu_events(void)
663 return &__get_cpu_var(cpu_hw_events);
666 static void __init cpu_pmu_init(struct arm_pmu *armpmu)
668 int cpu;
669 for_each_possible_cpu(cpu) {
670 struct pmu_hw_events *events = &per_cpu(cpu_hw_events, cpu);
671 events->events = per_cpu(hw_events, cpu);
672 events->used_mask = per_cpu(used_mask, cpu);
673 raw_spin_lock_init(&events->pmu_lock);
675 armpmu->get_hw_events = armpmu_get_cpu_events;
676 armpmu->type = ARM_PMU_DEVICE_CPU;
680 * CPU PMU identification and registration.
682 static int __init
683 init_hw_perf_events(void)
685 unsigned long cpuid = read_cpuid_id();
686 unsigned long implementor = (cpuid & 0xFF000000) >> 24;
687 unsigned long part_number = (cpuid & 0xFFF0);
689 /* ARM Ltd CPUs. */
690 if (0x41 == implementor) {
691 switch (part_number) {
692 case 0xB360: /* ARM1136 */
693 case 0xB560: /* ARM1156 */
694 case 0xB760: /* ARM1176 */
695 cpu_pmu = armv6pmu_init();
696 break;
697 case 0xB020: /* ARM11mpcore */
698 cpu_pmu = armv6mpcore_pmu_init();
699 break;
700 case 0xC080: /* Cortex-A8 */
701 cpu_pmu = armv7_a8_pmu_init();
702 break;
703 case 0xC090: /* Cortex-A9 */
704 cpu_pmu = armv7_a9_pmu_init();
705 break;
706 case 0xC050: /* Cortex-A5 */
707 cpu_pmu = armv7_a5_pmu_init();
708 break;
709 case 0xC0F0: /* Cortex-A15 */
710 cpu_pmu = armv7_a15_pmu_init();
711 break;
713 /* Intel CPUs [xscale]. */
714 } else if (0x69 == implementor) {
715 part_number = (cpuid >> 13) & 0x7;
716 switch (part_number) {
717 case 1:
718 cpu_pmu = xscale1pmu_init();
719 break;
720 case 2:
721 cpu_pmu = xscale2pmu_init();
722 break;
726 if (cpu_pmu) {
727 pr_info("enabled with %s PMU driver, %d counters available\n",
728 cpu_pmu->name, cpu_pmu->num_events);
729 cpu_pmu_init(cpu_pmu);
730 armpmu_register(cpu_pmu, "cpu", PERF_TYPE_RAW);
731 } else {
732 pr_info("no hardware support available\n");
735 return 0;
737 early_initcall(init_hw_perf_events);
740 * Callchain handling code.
744 * The registers we're interested in are at the end of the variable
745 * length saved register structure. The fp points at the end of this
746 * structure so the address of this struct is:
747 * (struct frame_tail *)(xxx->fp)-1
749 * This code has been adapted from the ARM OProfile support.
751 struct frame_tail {
752 struct frame_tail __user *fp;
753 unsigned long sp;
754 unsigned long lr;
755 } __attribute__((packed));
758 * Get the return address for a single stackframe and return a pointer to the
759 * next frame tail.
761 static struct frame_tail __user *
762 user_backtrace(struct frame_tail __user *tail,
763 struct perf_callchain_entry *entry)
765 struct frame_tail buftail;
767 /* Also check accessibility of one struct frame_tail beyond */
768 if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
769 return NULL;
770 if (__copy_from_user_inatomic(&buftail, tail, sizeof(buftail)))
771 return NULL;
773 perf_callchain_store(entry, buftail.lr);
776 * Frame pointers should strictly progress back up the stack
777 * (towards higher addresses).
779 if (tail + 1 >= buftail.fp)
780 return NULL;
782 return buftail.fp - 1;
785 void
786 perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs)
788 struct frame_tail __user *tail;
791 tail = (struct frame_tail __user *)regs->ARM_fp - 1;
793 while ((entry->nr < PERF_MAX_STACK_DEPTH) &&
794 tail && !((unsigned long)tail & 0x3))
795 tail = user_backtrace(tail, entry);
799 * Gets called by walk_stackframe() for every stackframe. This will be called
800 * whist unwinding the stackframe and is like a subroutine return so we use
801 * the PC.
803 static int
804 callchain_trace(struct stackframe *fr,
805 void *data)
807 struct perf_callchain_entry *entry = data;
808 perf_callchain_store(entry, fr->pc);
809 return 0;
812 void
813 perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs)
815 struct stackframe fr;
817 fr.fp = regs->ARM_fp;
818 fr.sp = regs->ARM_sp;
819 fr.lr = regs->ARM_lr;
820 fr.pc = regs->ARM_pc;
821 walk_stackframe(&fr, callchain_trace, entry);