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
13 #define pr_fmt(fmt) "hw perfevents: " fmt
15 #include <linux/kernel.h>
16 #include <linux/platform_device.h>
17 #include <linux/pm_runtime.h>
18 #include <linux/uaccess.h>
20 #include <asm/irq_regs.h>
22 #include <asm/stacktrace.h>
25 armpmu_map_cache_event(const unsigned (*cache_map
)
26 [PERF_COUNT_HW_CACHE_MAX
]
27 [PERF_COUNT_HW_CACHE_OP_MAX
]
28 [PERF_COUNT_HW_CACHE_RESULT_MAX
],
31 unsigned int cache_type
, cache_op
, cache_result
, ret
;
33 cache_type
= (config
>> 0) & 0xff;
34 if (cache_type
>= PERF_COUNT_HW_CACHE_MAX
)
37 cache_op
= (config
>> 8) & 0xff;
38 if (cache_op
>= PERF_COUNT_HW_CACHE_OP_MAX
)
41 cache_result
= (config
>> 16) & 0xff;
42 if (cache_result
>= PERF_COUNT_HW_CACHE_RESULT_MAX
)
45 ret
= (int)(*cache_map
)[cache_type
][cache_op
][cache_result
];
47 if (ret
== CACHE_OP_UNSUPPORTED
)
54 armpmu_map_hw_event(const unsigned (*event_map
)[PERF_COUNT_HW_MAX
], u64 config
)
58 if (config
>= PERF_COUNT_HW_MAX
)
61 mapping
= (*event_map
)[config
];
62 return mapping
== HW_OP_UNSUPPORTED
? -ENOENT
: mapping
;
66 armpmu_map_raw_event(u32 raw_event_mask
, u64 config
)
68 return (int)(config
& raw_event_mask
);
72 armpmu_map_event(struct perf_event
*event
,
73 const unsigned (*event_map
)[PERF_COUNT_HW_MAX
],
74 const unsigned (*cache_map
)
75 [PERF_COUNT_HW_CACHE_MAX
]
76 [PERF_COUNT_HW_CACHE_OP_MAX
]
77 [PERF_COUNT_HW_CACHE_RESULT_MAX
],
80 u64 config
= event
->attr
.config
;
82 switch (event
->attr
.type
) {
83 case PERF_TYPE_HARDWARE
:
84 return armpmu_map_hw_event(event_map
, config
);
85 case PERF_TYPE_HW_CACHE
:
86 return armpmu_map_cache_event(cache_map
, config
);
88 return armpmu_map_raw_event(raw_event_mask
, config
);
94 int armpmu_event_set_period(struct perf_event
*event
)
96 struct arm_pmu
*armpmu
= to_arm_pmu(event
->pmu
);
97 struct hw_perf_event
*hwc
= &event
->hw
;
98 s64 left
= local64_read(&hwc
->period_left
);
99 s64 period
= hwc
->sample_period
;
102 /* The period may have been changed by PERF_EVENT_IOC_PERIOD */
103 if (unlikely(period
!= hwc
->last_period
))
104 left
= period
- (hwc
->last_period
- left
);
106 if (unlikely(left
<= -period
)) {
108 local64_set(&hwc
->period_left
, left
);
109 hwc
->last_period
= period
;
113 if (unlikely(left
<= 0)) {
115 local64_set(&hwc
->period_left
, left
);
116 hwc
->last_period
= period
;
120 if (left
> (s64
)armpmu
->max_period
)
121 left
= armpmu
->max_period
;
123 local64_set(&hwc
->prev_count
, (u64
)-left
);
125 armpmu
->write_counter(event
, (u64
)(-left
) & 0xffffffff);
127 perf_event_update_userpage(event
);
132 u64
armpmu_event_update(struct perf_event
*event
)
134 struct arm_pmu
*armpmu
= to_arm_pmu(event
->pmu
);
135 struct hw_perf_event
*hwc
= &event
->hw
;
136 u64 delta
, prev_raw_count
, new_raw_count
;
139 prev_raw_count
= local64_read(&hwc
->prev_count
);
140 new_raw_count
= armpmu
->read_counter(event
);
142 if (local64_cmpxchg(&hwc
->prev_count
, prev_raw_count
,
143 new_raw_count
) != prev_raw_count
)
146 delta
= (new_raw_count
- prev_raw_count
) & armpmu
->max_period
;
148 local64_add(delta
, &event
->count
);
149 local64_sub(delta
, &hwc
->period_left
);
151 return new_raw_count
;
155 armpmu_read(struct perf_event
*event
)
157 armpmu_event_update(event
);
161 armpmu_stop(struct perf_event
*event
, int flags
)
163 struct arm_pmu
*armpmu
= to_arm_pmu(event
->pmu
);
164 struct hw_perf_event
*hwc
= &event
->hw
;
167 * ARM pmu always has to update the counter, so ignore
168 * PERF_EF_UPDATE, see comments in armpmu_start().
170 if (!(hwc
->state
& PERF_HES_STOPPED
)) {
171 armpmu
->disable(event
);
172 armpmu_event_update(event
);
173 hwc
->state
|= PERF_HES_STOPPED
| PERF_HES_UPTODATE
;
177 static void armpmu_start(struct perf_event
*event
, int flags
)
179 struct arm_pmu
*armpmu
= to_arm_pmu(event
->pmu
);
180 struct hw_perf_event
*hwc
= &event
->hw
;
183 * ARM pmu always has to reprogram the period, so ignore
184 * PERF_EF_RELOAD, see the comment below.
186 if (flags
& PERF_EF_RELOAD
)
187 WARN_ON_ONCE(!(hwc
->state
& PERF_HES_UPTODATE
));
191 * Set the period again. Some counters can't be stopped, so when we
192 * were stopped we simply disabled the IRQ source and the counter
193 * may have been left counting. If we don't do this step then we may
194 * get an interrupt too soon or *way* too late if the overflow has
195 * happened since disabling.
197 armpmu_event_set_period(event
);
198 armpmu
->enable(event
);
202 armpmu_del(struct perf_event
*event
, int flags
)
204 struct arm_pmu
*armpmu
= to_arm_pmu(event
->pmu
);
205 struct pmu_hw_events
*hw_events
= armpmu
->get_hw_events();
206 struct hw_perf_event
*hwc
= &event
->hw
;
209 armpmu_stop(event
, PERF_EF_UPDATE
);
210 hw_events
->events
[idx
] = NULL
;
211 clear_bit(idx
, hw_events
->used_mask
);
213 perf_event_update_userpage(event
);
217 armpmu_add(struct perf_event
*event
, int flags
)
219 struct arm_pmu
*armpmu
= to_arm_pmu(event
->pmu
);
220 struct pmu_hw_events
*hw_events
= armpmu
->get_hw_events();
221 struct hw_perf_event
*hwc
= &event
->hw
;
225 perf_pmu_disable(event
->pmu
);
227 /* If we don't have a space for the counter then finish early. */
228 idx
= armpmu
->get_event_idx(hw_events
, event
);
235 * If there is an event in the counter we are going to use then make
236 * sure it is disabled.
239 armpmu
->disable(event
);
240 hw_events
->events
[idx
] = event
;
242 hwc
->state
= PERF_HES_STOPPED
| PERF_HES_UPTODATE
;
243 if (flags
& PERF_EF_START
)
244 armpmu_start(event
, PERF_EF_RELOAD
);
246 /* Propagate our changes to the userspace mapping. */
247 perf_event_update_userpage(event
);
250 perf_pmu_enable(event
->pmu
);
255 validate_event(struct pmu_hw_events
*hw_events
,
256 struct perf_event
*event
)
258 struct arm_pmu
*armpmu
= to_arm_pmu(event
->pmu
);
259 struct pmu
*leader_pmu
= event
->group_leader
->pmu
;
261 if (is_software_event(event
))
264 if (event
->pmu
!= leader_pmu
|| event
->state
< PERF_EVENT_STATE_OFF
)
267 if (event
->state
== PERF_EVENT_STATE_OFF
&& !event
->attr
.enable_on_exec
)
270 return armpmu
->get_event_idx(hw_events
, event
) >= 0;
274 validate_group(struct perf_event
*event
)
276 struct perf_event
*sibling
, *leader
= event
->group_leader
;
277 struct pmu_hw_events fake_pmu
;
278 DECLARE_BITMAP(fake_used_mask
, ARMPMU_MAX_HWEVENTS
);
281 * Initialise the fake PMU. We only need to populate the
282 * used_mask for the purposes of validation.
284 memset(fake_used_mask
, 0, sizeof(fake_used_mask
));
285 fake_pmu
.used_mask
= fake_used_mask
;
287 if (!validate_event(&fake_pmu
, leader
))
290 list_for_each_entry(sibling
, &leader
->sibling_list
, group_entry
) {
291 if (!validate_event(&fake_pmu
, sibling
))
295 if (!validate_event(&fake_pmu
, event
))
301 static irqreturn_t
armpmu_dispatch_irq(int irq
, void *dev
)
303 struct arm_pmu
*armpmu
= (struct arm_pmu
*) dev
;
304 struct platform_device
*plat_device
= armpmu
->plat_device
;
305 struct arm_pmu_platdata
*plat
= dev_get_platdata(&plat_device
->dev
);
307 u64 start_clock
, finish_clock
;
309 start_clock
= sched_clock();
310 if (plat
&& plat
->handle_irq
)
311 ret
= plat
->handle_irq(irq
, dev
, armpmu
->handle_irq
);
313 ret
= armpmu
->handle_irq(irq
, dev
);
314 finish_clock
= sched_clock();
316 perf_sample_event_took(finish_clock
- start_clock
);
321 armpmu_release_hardware(struct arm_pmu
*armpmu
)
323 armpmu
->free_irq(armpmu
);
324 pm_runtime_put_sync(&armpmu
->plat_device
->dev
);
328 armpmu_reserve_hardware(struct arm_pmu
*armpmu
)
331 struct platform_device
*pmu_device
= armpmu
->plat_device
;
336 pm_runtime_get_sync(&pmu_device
->dev
);
337 err
= armpmu
->request_irq(armpmu
, armpmu_dispatch_irq
);
339 armpmu_release_hardware(armpmu
);
347 hw_perf_event_destroy(struct perf_event
*event
)
349 struct arm_pmu
*armpmu
= to_arm_pmu(event
->pmu
);
350 atomic_t
*active_events
= &armpmu
->active_events
;
351 struct mutex
*pmu_reserve_mutex
= &armpmu
->reserve_mutex
;
353 if (atomic_dec_and_mutex_lock(active_events
, pmu_reserve_mutex
)) {
354 armpmu_release_hardware(armpmu
);
355 mutex_unlock(pmu_reserve_mutex
);
360 event_requires_mode_exclusion(struct perf_event_attr
*attr
)
362 return attr
->exclude_idle
|| attr
->exclude_user
||
363 attr
->exclude_kernel
|| attr
->exclude_hv
;
367 __hw_perf_event_init(struct perf_event
*event
)
369 struct arm_pmu
*armpmu
= to_arm_pmu(event
->pmu
);
370 struct hw_perf_event
*hwc
= &event
->hw
;
373 mapping
= armpmu
->map_event(event
);
376 pr_debug("event %x:%llx not supported\n", event
->attr
.type
,
382 * We don't assign an index until we actually place the event onto
383 * hardware. Use -1 to signify that we haven't decided where to put it
384 * yet. For SMP systems, each core has it's own PMU so we can't do any
385 * clever allocation or constraints checking at this point.
388 hwc
->config_base
= 0;
393 * Check whether we need to exclude the counter from certain modes.
395 if ((!armpmu
->set_event_filter
||
396 armpmu
->set_event_filter(hwc
, &event
->attr
)) &&
397 event_requires_mode_exclusion(&event
->attr
)) {
398 pr_debug("ARM performance counters do not support "
404 * Store the event encoding into the config_base field.
406 hwc
->config_base
|= (unsigned long)mapping
;
408 if (!hwc
->sample_period
) {
410 * For non-sampling runs, limit the sample_period to half
411 * of the counter width. That way, the new counter value
412 * is far less likely to overtake the previous one unless
413 * you have some serious IRQ latency issues.
415 hwc
->sample_period
= armpmu
->max_period
>> 1;
416 hwc
->last_period
= hwc
->sample_period
;
417 local64_set(&hwc
->period_left
, hwc
->sample_period
);
420 if (event
->group_leader
!= event
) {
421 if (validate_group(event
) != 0)
428 static int armpmu_event_init(struct perf_event
*event
)
430 struct arm_pmu
*armpmu
= to_arm_pmu(event
->pmu
);
432 atomic_t
*active_events
= &armpmu
->active_events
;
434 /* does not support taken branch sampling */
435 if (has_branch_stack(event
))
438 if (armpmu
->map_event(event
) == -ENOENT
)
441 event
->destroy
= hw_perf_event_destroy
;
443 if (!atomic_inc_not_zero(active_events
)) {
444 mutex_lock(&armpmu
->reserve_mutex
);
445 if (atomic_read(active_events
) == 0)
446 err
= armpmu_reserve_hardware(armpmu
);
449 atomic_inc(active_events
);
450 mutex_unlock(&armpmu
->reserve_mutex
);
456 err
= __hw_perf_event_init(event
);
458 hw_perf_event_destroy(event
);
463 static void armpmu_enable(struct pmu
*pmu
)
465 struct arm_pmu
*armpmu
= to_arm_pmu(pmu
);
466 struct pmu_hw_events
*hw_events
= armpmu
->get_hw_events();
467 int enabled
= bitmap_weight(hw_events
->used_mask
, armpmu
->num_events
);
470 armpmu
->start(armpmu
);
473 static void armpmu_disable(struct pmu
*pmu
)
475 struct arm_pmu
*armpmu
= to_arm_pmu(pmu
);
476 armpmu
->stop(armpmu
);
479 #ifdef CONFIG_PM_RUNTIME
480 static int armpmu_runtime_resume(struct device
*dev
)
482 struct arm_pmu_platdata
*plat
= dev_get_platdata(dev
);
484 if (plat
&& plat
->runtime_resume
)
485 return plat
->runtime_resume(dev
);
490 static int armpmu_runtime_suspend(struct device
*dev
)
492 struct arm_pmu_platdata
*plat
= dev_get_platdata(dev
);
494 if (plat
&& plat
->runtime_suspend
)
495 return plat
->runtime_suspend(dev
);
501 const struct dev_pm_ops armpmu_dev_pm_ops
= {
502 SET_RUNTIME_PM_OPS(armpmu_runtime_suspend
, armpmu_runtime_resume
, NULL
)
505 static void armpmu_init(struct arm_pmu
*armpmu
)
507 atomic_set(&armpmu
->active_events
, 0);
508 mutex_init(&armpmu
->reserve_mutex
);
510 armpmu
->pmu
= (struct pmu
) {
511 .pmu_enable
= armpmu_enable
,
512 .pmu_disable
= armpmu_disable
,
513 .event_init
= armpmu_event_init
,
516 .start
= armpmu_start
,
522 int armpmu_register(struct arm_pmu
*armpmu
, int type
)
525 pm_runtime_enable(&armpmu
->plat_device
->dev
);
526 pr_info("enabled with %s PMU driver, %d counters available\n",
527 armpmu
->name
, armpmu
->num_events
);
528 return perf_pmu_register(&armpmu
->pmu
, armpmu
->name
, type
);
532 * Callchain handling code.
536 * The registers we're interested in are at the end of the variable
537 * length saved register structure. The fp points at the end of this
538 * structure so the address of this struct is:
539 * (struct frame_tail *)(xxx->fp)-1
541 * This code has been adapted from the ARM OProfile support.
544 struct frame_tail __user
*fp
;
547 } __attribute__((packed
));
550 * Get the return address for a single stackframe and return a pointer to the
553 static struct frame_tail __user
*
554 user_backtrace(struct frame_tail __user
*tail
,
555 struct perf_callchain_entry
*entry
)
557 struct frame_tail buftail
;
559 /* Also check accessibility of one struct frame_tail beyond */
560 if (!access_ok(VERIFY_READ
, tail
, sizeof(buftail
)))
562 if (__copy_from_user_inatomic(&buftail
, tail
, sizeof(buftail
)))
565 perf_callchain_store(entry
, buftail
.lr
);
568 * Frame pointers should strictly progress back up the stack
569 * (towards higher addresses).
571 if (tail
+ 1 >= buftail
.fp
)
574 return buftail
.fp
- 1;
578 perf_callchain_user(struct perf_callchain_entry
*entry
, struct pt_regs
*regs
)
580 struct frame_tail __user
*tail
;
582 if (perf_guest_cbs
&& perf_guest_cbs
->is_in_guest()) {
583 /* We don't support guest os callchain now */
587 perf_callchain_store(entry
, regs
->ARM_pc
);
588 tail
= (struct frame_tail __user
*)regs
->ARM_fp
- 1;
590 while ((entry
->nr
< PERF_MAX_STACK_DEPTH
) &&
591 tail
&& !((unsigned long)tail
& 0x3))
592 tail
= user_backtrace(tail
, entry
);
596 * Gets called by walk_stackframe() for every stackframe. This will be called
597 * whist unwinding the stackframe and is like a subroutine return so we use
601 callchain_trace(struct stackframe
*fr
,
604 struct perf_callchain_entry
*entry
= data
;
605 perf_callchain_store(entry
, fr
->pc
);
610 perf_callchain_kernel(struct perf_callchain_entry
*entry
, struct pt_regs
*regs
)
612 struct stackframe fr
;
614 if (perf_guest_cbs
&& perf_guest_cbs
->is_in_guest()) {
615 /* We don't support guest os callchain now */
619 fr
.fp
= regs
->ARM_fp
;
620 fr
.sp
= regs
->ARM_sp
;
621 fr
.lr
= regs
->ARM_lr
;
622 fr
.pc
= regs
->ARM_pc
;
623 walk_stackframe(&fr
, callchain_trace
, entry
);
626 unsigned long perf_instruction_pointer(struct pt_regs
*regs
)
628 if (perf_guest_cbs
&& perf_guest_cbs
->is_in_guest())
629 return perf_guest_cbs
->get_guest_ip();
631 return instruction_pointer(regs
);
634 unsigned long perf_misc_flags(struct pt_regs
*regs
)
638 if (perf_guest_cbs
&& perf_guest_cbs
->is_in_guest()) {
639 if (perf_guest_cbs
->is_user_mode())
640 misc
|= PERF_RECORD_MISC_GUEST_USER
;
642 misc
|= PERF_RECORD_MISC_GUEST_KERNEL
;
645 misc
|= PERF_RECORD_MISC_USER
;
647 misc
|= PERF_RECORD_MISC_KERNEL
;