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/*
* ARM performance counter support.
*
* Copyright (C) 2009 picoChip Designs, Ltd., Jamie Iles
* Copyright (C) 2010 ARM Ltd., Will Deacon <will.deacon@arm.com>
*
* This code is based on the sparc64 perf event code, which is in turn based
* on the x86 code. Callchain code is based on the ARM OProfile backtrace
* code.
*/
#define pr_fmt(fmt) "hw perfevents: " fmt
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/perf_event.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <asm/cputype.h>
#include <asm/irq.h>
#include <asm/irq_regs.h>
#include <asm/pmu.h>
#include <asm/stacktrace.h>
static struct platform_device *pmu_device;
/*
* Hardware lock to serialize accesses to PMU registers. Needed for the
* read/modify/write sequences.
*/
static DEFINE_RAW_SPINLOCK(pmu_lock);
/*
* ARMv6 supports a maximum of 3 events, starting from index 1. If we add
* another platform that supports more, we need to increase this to be the
* largest of all platforms.
*
* ARMv7 supports up to 32 events:
* cycle counter CCNT + 31 events counters CNT0..30.
* Cortex-A8 has 1+4 counters, Cortex-A9 has 1+6 counters.
*/
#define ARMPMU_MAX_HWEVENTS 33
/* The events for a given CPU. */
struct cpu_hw_events {
/*
* The events that are active on the CPU for the given index. Index 0
* is reserved.
*/
struct perf_event *events[ARMPMU_MAX_HWEVENTS];
/*
* A 1 bit for an index indicates that the counter is being used for
* an event. A 0 means that the counter can be used.
*/
unsigned long used_mask[BITS_TO_LONGS(ARMPMU_MAX_HWEVENTS)];
/*
* A 1 bit for an index indicates that the counter is actively being
* used.
*/
unsigned long active_mask[BITS_TO_LONGS(ARMPMU_MAX_HWEVENTS)];
};
static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events);
struct arm_pmu {
enum arm_perf_pmu_ids id;
const char *name;
irqreturn_t (*handle_irq)(int irq_num, void *dev);
void (*enable)(struct hw_perf_event *evt, int idx);
void (*disable)(struct hw_perf_event *evt, int idx);
int (*get_event_idx)(struct cpu_hw_events *cpuc,
struct hw_perf_event *hwc);
u32 (*read_counter)(int idx);
void (*write_counter)(int idx, u32 val);
void (*start)(void);
void (*stop)(void);
void (*reset)(void *);
const unsigned (*cache_map)[PERF_COUNT_HW_CACHE_MAX]
[PERF_COUNT_HW_CACHE_OP_MAX]
[PERF_COUNT_HW_CACHE_RESULT_MAX];
const unsigned (*event_map)[PERF_COUNT_HW_MAX];
u32 raw_event_mask;
int num_events;
u64 max_period;
};
/* Set at runtime when we know what CPU type we are. */
static const struct arm_pmu *armpmu;
enum arm_perf_pmu_ids
armpmu_get_pmu_id(void)
{
int id = -ENODEV;
if (armpmu != NULL)
id = armpmu->id;
return id;
}
EXPORT_SYMBOL_GPL(armpmu_get_pmu_id);
int
armpmu_get_max_events(void)
{
int max_events = 0;
if (armpmu != NULL)
max_events = armpmu->num_events;
return max_events;
}
EXPORT_SYMBOL_GPL(armpmu_get_max_events);
int perf_num_counters(void)
{
return armpmu_get_max_events();
}
EXPORT_SYMBOL_GPL(perf_num_counters);
#define HW_OP_UNSUPPORTED 0xFFFF
#define C(_x) \
PERF_COUNT_HW_CACHE_##_x
#define CACHE_OP_UNSUPPORTED 0xFFFF
static int
armpmu_map_cache_event(u64 config)
{
unsigned int cache_type, cache_op, cache_result, ret;
cache_type = (config >> 0) & 0xff;
if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
return -EINVAL;
cache_op = (config >> 8) & 0xff;
if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
return -EINVAL;
cache_result = (config >> 16) & 0xff;
if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
return -EINVAL;
ret = (int)(*armpmu->cache_map)[cache_type][cache_op][cache_result];
if (ret == CACHE_OP_UNSUPPORTED)
return -ENOENT;
return ret;
}
static int
armpmu_map_event(u64 config)
{
int mapping = (*armpmu->event_map)[config];
return mapping == HW_OP_UNSUPPORTED ? -EOPNOTSUPP : mapping;
}
static int
armpmu_map_raw_event(u64 config)
{
return (int)(config & armpmu->raw_event_mask);
}
static int
armpmu_event_set_period(struct perf_event *event,
struct hw_perf_event *hwc,
int idx)
{
s64 left = local64_read(&hwc->period_left);
s64 period = hwc->sample_period;
int ret = 0;
if (unlikely(left <= -period)) {
left = period;
local64_set(&hwc->period_left, left);
hwc->last_period = period;
ret = 1;
}
if (unlikely(left <= 0)) {
left += period;
local64_set(&hwc->period_left, left);
hwc->last_period = period;
ret = 1;
}
if (left > (s64)armpmu->max_period)
left = armpmu->max_period;
local64_set(&hwc->prev_count, (u64)-left);
armpmu->write_counter(idx, (u64)(-left) & 0xffffffff);
perf_event_update_userpage(event);
return ret;
}
static u64
armpmu_event_update(struct perf_event *event,
struct hw_perf_event *hwc,
int idx, int overflow)
{
u64 delta, prev_raw_count, new_raw_count;
again:
prev_raw_count = local64_read(&hwc->prev_count);
new_raw_count = armpmu->read_counter(idx);
if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
new_raw_count) != prev_raw_count)
goto again;
new_raw_count &= armpmu->max_period;
prev_raw_count &= armpmu->max_period;
if (overflow)
delta = armpmu->max_period - prev_raw_count + new_raw_count + 1;
else
delta = new_raw_count - prev_raw_count;
local64_add(delta, &event->count);
local64_sub(delta, &hwc->period_left);
return new_raw_count;
}
static void
armpmu_read(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
/* Don't read disabled counters! */
if (hwc->idx < 0)
return;
armpmu_event_update(event, hwc, hwc->idx, 0);
}
static void
armpmu_stop(struct perf_event *event, int flags)
{
struct hw_perf_event *hwc = &event->hw;
if (!armpmu)
return;
/*
* ARM pmu always has to update the counter, so ignore
* PERF_EF_UPDATE, see comments in armpmu_start().
*/
if (!(hwc->state & PERF_HES_STOPPED)) {
armpmu->disable(hwc, hwc->idx);
barrier(); /* why? */
armpmu_event_update(event, hwc, hwc->idx, 0);
hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
}
}
static void
armpmu_start(struct perf_event *event, int flags)
{
struct hw_perf_event *hwc = &event->hw;
if (!armpmu)
return;
/*
* ARM pmu always has to reprogram the period, so ignore
* PERF_EF_RELOAD, see the comment below.
*/
if (flags & PERF_EF_RELOAD)
WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
hwc->state = 0;
/*
* Set the period again. Some counters can't be stopped, so when we
* were stopped we simply disabled the IRQ source and the counter
* may have been left counting. If we don't do this step then we may
* get an interrupt too soon or *way* too late if the overflow has
* happened since disabling.
*/
armpmu_event_set_period(event, hwc, hwc->idx);
armpmu->enable(hwc, hwc->idx);
}
static void
armpmu_del(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
struct hw_perf_event *hwc = &event->hw;
int idx = hwc->idx;
WARN_ON(idx < 0);
clear_bit(idx, cpuc->active_mask);
armpmu_stop(event, PERF_EF_UPDATE);
cpuc->events[idx] = NULL;
clear_bit(idx, cpuc->used_mask);
perf_event_update_userpage(event);
}
static int
armpmu_add(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
struct hw_perf_event *hwc = &event->hw;
int idx;
int err = 0;
perf_pmu_disable(event->pmu);
/* If we don't have a space for the counter then finish early. */
idx = armpmu->get_event_idx(cpuc, hwc);
if (idx < 0) {
err = idx;
goto out;
}
/*
* If there is an event in the counter we are going to use then make
* sure it is disabled.
*/
event->hw.idx = idx;
armpmu->disable(hwc, idx);
cpuc->events[idx] = event;
set_bit(idx, cpuc->active_mask);
hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
if (flags & PERF_EF_START)
armpmu_start(event, PERF_EF_RELOAD);
/* Propagate our changes to the userspace mapping. */
perf_event_update_userpage(event);
out:
perf_pmu_enable(event->pmu);
return err;
}
static struct pmu pmu;
static int
validate_event(struct cpu_hw_events *cpuc,
struct perf_event *event)
{
struct hw_perf_event fake_event = event->hw;
if (event->pmu != &pmu || event->state <= PERF_EVENT_STATE_OFF)
return 1;
return armpmu->get_event_idx(cpuc, &fake_event) >= 0;
}
static int
validate_group(struct perf_event *event)
{
struct perf_event *sibling, *leader = event->group_leader;
struct cpu_hw_events fake_pmu;
memset(&fake_pmu, 0, sizeof(fake_pmu));
if (!validate_event(&fake_pmu, leader))
return -ENOSPC;
list_for_each_entry(sibling, &leader->sibling_list, group_entry) {
if (!validate_event(&fake_pmu, sibling))
return -ENOSPC;
}
if (!validate_event(&fake_pmu, event))
return -ENOSPC;
return 0;
}
static irqreturn_t armpmu_platform_irq(int irq, void *dev)
{
struct arm_pmu_platdata *plat = dev_get_platdata(&pmu_device->dev);
return plat->handle_irq(irq, dev, armpmu->handle_irq);
}
static int
armpmu_reserve_hardware(void)
{
struct arm_pmu_platdata *plat;
irq_handler_t handle_irq;
int i, err = -ENODEV, irq;
pmu_device = reserve_pmu(ARM_PMU_DEVICE_CPU);
if (IS_ERR(pmu_device)) {
pr_warning("unable to reserve pmu\n");
return PTR_ERR(pmu_device);
}
init_pmu(ARM_PMU_DEVICE_CPU);
plat = dev_get_platdata(&pmu_device->dev);
if (plat && plat->handle_irq)
handle_irq = armpmu_platform_irq;
else
handle_irq = armpmu->handle_irq;
if (pmu_device->num_resources < 1) {
pr_err("no irqs for PMUs defined\n");
return -ENODEV;
}
for (i = 0; i < pmu_device->num_resources; ++i) {
irq = platform_get_irq(pmu_device, i);
if (irq < 0)
continue;
err = request_irq(irq, handle_irq,
IRQF_DISABLED | IRQF_NOBALANCING,
"armpmu", NULL);
if (err) {
pr_warning("unable to request IRQ%d for ARM perf "
"counters\n", irq);
break;
}
}
if (err) {
for (i = i - 1; i >= 0; --i) {
irq = platform_get_irq(pmu_device, i);
if (irq >= 0)
free_irq(irq, NULL);
}
release_pmu(pmu_device);
pmu_device = NULL;
}
return err;
}
static void
armpmu_release_hardware(void)
{
int i, irq;
for (i = pmu_device->num_resources - 1; i >= 0; --i) {
irq = platform_get_irq(pmu_device, i);
if (irq >= 0)
free_irq(irq, NULL);
}
armpmu->stop();
release_pmu(pmu_device);
pmu_device = NULL;
}
static atomic_t active_events = ATOMIC_INIT(0);
static DEFINE_MUTEX(pmu_reserve_mutex);
static void
hw_perf_event_destroy(struct perf_event *event)
{
if (atomic_dec_and_mutex_lock(&active_events, &pmu_reserve_mutex)) {
armpmu_release_hardware();
mutex_unlock(&pmu_reserve_mutex);
}
}
static int
__hw_perf_event_init(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
int mapping, err;
/* Decode the generic type into an ARM event identifier. */
if (PERF_TYPE_HARDWARE == event->attr.type) {
mapping = armpmu_map_event(event->attr.config);
} else if (PERF_TYPE_HW_CACHE == event->attr.type) {
mapping = armpmu_map_cache_event(event->attr.config);
} else if (PERF_TYPE_RAW == event->attr.type) {
mapping = armpmu_map_raw_event(event->attr.config);
} else {
pr_debug("event type %x not supported\n", event->attr.type);
return -EOPNOTSUPP;
}
if (mapping < 0) {
pr_debug("event %x:%llx not supported\n", event->attr.type,
event->attr.config);
return mapping;
}
/*
* Check whether we need to exclude the counter from certain modes.
* The ARM performance counters are on all of the time so if someone
* has asked us for some excludes then we have to fail.
*/
if (event->attr.exclude_kernel || event->attr.exclude_user ||
event->attr.exclude_hv || event->attr.exclude_idle) {
pr_debug("ARM performance counters do not support "
"mode exclusion\n");
return -EPERM;
}
/*
* We don't assign an index until we actually place the event onto
* hardware. Use -1 to signify that we haven't decided where to put it
* yet. For SMP systems, each core has it's own PMU so we can't do any
* clever allocation or constraints checking at this point.
*/
hwc->idx = -1;
/*
* Store the event encoding into the config_base field. config and
* event_base are unused as the only 2 things we need to know are
* the event mapping and the counter to use. The counter to use is
* also the indx and the config_base is the event type.
*/
hwc->config_base = (unsigned long)mapping;
hwc->config = 0;
hwc->event_base = 0;
if (!hwc->sample_period) {
hwc->sample_period = armpmu->max_period;
hwc->last_period = hwc->sample_period;
local64_set(&hwc->period_left, hwc->sample_period);
}
err = 0;
if (event->group_leader != event) {
err = validate_group(event);
if (err)
return -EINVAL;
}
return err;
}
static int armpmu_event_init(struct perf_event *event)
{
int err = 0;
switch (event->attr.type) {
case PERF_TYPE_RAW:
case PERF_TYPE_HARDWARE:
case PERF_TYPE_HW_CACHE:
break;
default:
return -ENOENT;
}
if (!armpmu)
return -ENODEV;
event->destroy = hw_perf_event_destroy;
if (!atomic_inc_not_zero(&active_events)) {
mutex_lock(&pmu_reserve_mutex);
if (atomic_read(&active_events) == 0) {
err = armpmu_reserve_hardware();
}
if (!err)
atomic_inc(&active_events);
mutex_unlock(&pmu_reserve_mutex);
}
if (err)
return err;
err = __hw_perf_event_init(event);
if (err)
hw_perf_event_destroy(event);
return err;
}
static void armpmu_enable(struct pmu *pmu)
{
/* Enable all of the perf events on hardware. */
int idx, enabled = 0;
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
if (!armpmu)
return;
for (idx = 0; idx <= armpmu->num_events; ++idx) {
struct perf_event *event = cpuc->events[idx];
if (!event)
continue;
armpmu->enable(&event->hw, idx);
enabled = 1;
}
if (enabled)
armpmu->start();
}
static void armpmu_disable(struct pmu *pmu)
{
if (armpmu)
armpmu->stop();
}
static struct pmu pmu = {
.pmu_enable = armpmu_enable,
.pmu_disable = armpmu_disable,
.event_init = armpmu_event_init,
.add = armpmu_add,
.del = armpmu_del,
.start = armpmu_start,
.stop = armpmu_stop,
.read = armpmu_read,
};
/* Include the PMU-specific implementations. */
#include "perf_event_xscale.c"
#include "perf_event_v6.c"
#include "perf_event_v7.c"
/*
* Ensure the PMU has sane values out of reset.
* This requires SMP to be available, so exists as a separate initcall.
*/
static int __init
armpmu_reset(void)
{
if (armpmu && armpmu->reset)
return on_each_cpu(armpmu->reset, NULL, 1);
return 0;
}
arch_initcall(armpmu_reset);
static int __init
init_hw_perf_events(void)
{
unsigned long cpuid = read_cpuid_id();
unsigned long implementor = (cpuid & 0xFF000000) >> 24;
unsigned long part_number = (cpuid & 0xFFF0);
/* ARM Ltd CPUs. */
if (0x41 == implementor) {
switch (part_number) {
case 0xB360: /* ARM1136 */
case 0xB560: /* ARM1156 */
case 0xB760: /* ARM1176 */
armpmu = armv6pmu_init();
break;
case 0xB020: /* ARM11mpcore */
armpmu = armv6mpcore_pmu_init();
break;
case 0xC080: /* Cortex-A8 */
armpmu = armv7_a8_pmu_init();
break;
case 0xC090: /* Cortex-A9 */
armpmu = armv7_a9_pmu_init();
break;
}
/* Intel CPUs [xscale]. */
} else if (0x69 == implementor) {
part_number = (cpuid >> 13) & 0x7;
switch (part_number) {
case 1:
armpmu = xscale1pmu_init();
break;
case 2:
armpmu = xscale2pmu_init();
break;
}
}
if (armpmu) {
pr_info("enabled with %s PMU driver, %d counters available\n",
armpmu->name, armpmu->num_events);
} else {
pr_info("no hardware support available\n");
}
perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
return 0;
}
early_initcall(init_hw_perf_events);
/*
* Callchain handling code.
*/
/*
* The registers we're interested in are at the end of the variable
* length saved register structure. The fp points at the end of this
* structure so the address of this struct is:
* (struct frame_tail *)(xxx->fp)-1
*
* This code has been adapted from the ARM OProfile support.
*/
struct frame_tail {
struct frame_tail __user *fp;
unsigned long sp;
unsigned long lr;
} __attribute__((packed));
/*
* Get the return address for a single stackframe and return a pointer to the
* next frame tail.
*/
static struct frame_tail __user *
user_backtrace(struct frame_tail __user *tail,
struct perf_callchain_entry *entry)
{
struct frame_tail buftail;
/* Also check accessibility of one struct frame_tail beyond */
if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
return NULL;
if (__copy_from_user_inatomic(&buftail, tail, sizeof(buftail)))
return NULL;
perf_callchain_store(entry, buftail.lr);
/*
* Frame pointers should strictly progress back up the stack
* (towards higher addresses).
*/
if (tail + 1 >= buftail.fp)
return NULL;
return buftail.fp - 1;
}
void
perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs)
{
struct frame_tail __user *tail;
perf_callchain_store(entry, regs->ARM_pc);
tail = (struct frame_tail __user *)regs->ARM_fp - 1;
while ((entry->nr < PERF_MAX_STACK_DEPTH) &&
tail && !((unsigned long)tail & 0x3))
tail = user_backtrace(tail, entry);
}
/*
* Gets called by walk_stackframe() for every stackframe. This will be called
* whist unwinding the stackframe and is like a subroutine return so we use
* the PC.
*/
static int
callchain_trace(struct stackframe *fr,
void *data)
{
struct perf_callchain_entry *entry = data;
perf_callchain_store(entry, fr->pc);
return 0;
}
void
perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs)
{
struct stackframe fr;
fr.fp = regs->ARM_fp;
fr.sp = regs->ARM_sp;
fr.lr = regs->ARM_lr;
fr.pc = regs->ARM_pc;
walk_stackframe(&fr, callchain_trace, entry);
}
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