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ARM: perf: add support for multiple PMUs
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Currently, a single static instance of struct pmu is used when
registering an ARM PMU with the main perf subsystem. This limits
the ARM perf code to supporting a single PMU.

This patch replaces the static struct pmu instance with a member
variable on struct arm_pmu. This provides bidirectional mapping
between the two structs, and therefore allows for support of multiple
PMUs. The function 'to_arm_pmu' is provided for convenience.

PMU-generic functions are also updated to use the new mapping, and
PMU-generic initialisation of the member variables is moved into a new
function: armpmu_init.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Jamie Iles <jamie@jamieiles.com>
Reviewed-by: Ashwin Chaugule <ashwinc@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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Mark Rutland authored and Will Deacon committed Aug 31, 2011
1 parent e1f431b commit 8a16b34
Showing 1 changed file with 41 additions and 22 deletions.
63 changes: 41 additions & 22 deletions arch/arm/kernel/perf_event.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -59,6 +59,7 @@ struct cpu_hw_events {
static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events);

struct arm_pmu {
struct pmu pmu;
enum arm_perf_pmu_ids id;
enum arm_pmu_type type;
cpumask_t active_irqs;
Expand All @@ -84,6 +85,8 @@ struct arm_pmu {
struct cpu_hw_events *(*get_hw_events)(void);
};

#define to_arm_pmu(p) (container_of(p, struct arm_pmu, pmu))

/* Set at runtime when we know what CPU type we are. */
static struct arm_pmu *armpmu;

Expand Down Expand Up @@ -193,6 +196,7 @@ armpmu_event_set_period(struct perf_event *event,
struct hw_perf_event *hwc,
int idx)
{
struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
s64 left = local64_read(&hwc->period_left);
s64 period = hwc->sample_period;
int ret = 0;
Expand Down Expand Up @@ -228,6 +232,7 @@ armpmu_event_update(struct perf_event *event,
struct hw_perf_event *hwc,
int idx, int overflow)
{
struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
u64 delta, prev_raw_count, new_raw_count;

again:
Expand Down Expand Up @@ -267,6 +272,7 @@ armpmu_read(struct perf_event *event)
static void
armpmu_stop(struct perf_event *event, int flags)
{
struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
struct hw_perf_event *hwc = &event->hw;

/*
Expand All @@ -284,6 +290,7 @@ armpmu_stop(struct perf_event *event, int flags)
static void
armpmu_start(struct perf_event *event, int flags)
{
struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
struct hw_perf_event *hwc = &event->hw;

/*
Expand All @@ -308,6 +315,7 @@ armpmu_start(struct perf_event *event, int flags)
static void
armpmu_del(struct perf_event *event, int flags)
{
struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
struct cpu_hw_events *cpuc = armpmu->get_hw_events();
struct hw_perf_event *hwc = &event->hw;
int idx = hwc->idx;
Expand All @@ -324,6 +332,7 @@ armpmu_del(struct perf_event *event, int flags)
static int
armpmu_add(struct perf_event *event, int flags)
{
struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
struct cpu_hw_events *cpuc = armpmu->get_hw_events();
struct hw_perf_event *hwc = &event->hw;
int idx;
Expand Down Expand Up @@ -358,12 +367,11 @@ armpmu_add(struct perf_event *event, int flags)
return err;
}

static struct pmu pmu;

static int
validate_event(struct cpu_hw_events *cpuc,
struct perf_event *event)
{
struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
struct hw_perf_event fake_event = event->hw;
struct pmu *leader_pmu = event->group_leader->pmu;

Expand Down Expand Up @@ -397,14 +405,15 @@ validate_group(struct perf_event *event)

static irqreturn_t armpmu_platform_irq(int irq, void *dev)
{
struct arm_pmu *armpmu = (struct arm_pmu *) dev;
struct platform_device *plat_device = armpmu->plat_device;
struct arm_pmu_platdata *plat = dev_get_platdata(&plat_device->dev);

return plat->handle_irq(irq, dev, armpmu->handle_irq);
}

static void
armpmu_release_hardware(void)
armpmu_release_hardware(struct arm_pmu *armpmu)
{
int i, irq, irqs;
struct platform_device *pmu_device = armpmu->plat_device;
Expand All @@ -416,14 +425,14 @@ armpmu_release_hardware(void)
continue;
irq = platform_get_irq(pmu_device, i);
if (irq >= 0)
free_irq(irq, NULL);
free_irq(irq, armpmu);
}

release_pmu(armpmu->type);
}

static int
armpmu_reserve_hardware(void)
armpmu_reserve_hardware(struct arm_pmu *armpmu)
{
struct arm_pmu_platdata *plat;
irq_handler_t handle_irq;
Expand Down Expand Up @@ -467,11 +476,11 @@ armpmu_reserve_hardware(void)

err = request_irq(irq, handle_irq,
IRQF_DISABLED | IRQF_NOBALANCING,
"arm-pmu", NULL);
"arm-pmu", armpmu);
if (err) {
pr_err("unable to request IRQ%d for ARM PMU counters\n",
irq);
armpmu_release_hardware();
armpmu_release_hardware(armpmu);
return err;
}

Expand All @@ -484,11 +493,12 @@ armpmu_reserve_hardware(void)
static void
hw_perf_event_destroy(struct perf_event *event)
{
struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
atomic_t *active_events = &armpmu->active_events;
struct mutex *pmu_reserve_mutex = &armpmu->reserve_mutex;

if (atomic_dec_and_mutex_lock(active_events, pmu_reserve_mutex)) {
armpmu_release_hardware();
armpmu_release_hardware(armpmu);
mutex_unlock(pmu_reserve_mutex);
}
}
Expand All @@ -503,6 +513,7 @@ event_requires_mode_exclusion(struct perf_event_attr *attr)
static int
__hw_perf_event_init(struct perf_event *event)
{
struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
struct hw_perf_event *hwc = &event->hw;
int mapping, err;

Expand Down Expand Up @@ -559,6 +570,7 @@ __hw_perf_event_init(struct perf_event *event)

static int armpmu_event_init(struct perf_event *event)
{
struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
int err = 0;
atomic_t *active_events = &armpmu->active_events;

Expand All @@ -570,7 +582,7 @@ static int armpmu_event_init(struct perf_event *event)
if (!atomic_inc_not_zero(active_events)) {
mutex_lock(&armpmu->reserve_mutex);
if (atomic_read(active_events) == 0)
err = armpmu_reserve_hardware();
err = armpmu_reserve_hardware(armpmu);

if (!err)
atomic_inc(active_events);
Expand All @@ -589,6 +601,7 @@ static int armpmu_event_init(struct perf_event *event)

static void armpmu_enable(struct pmu *pmu)
{
struct arm_pmu *armpmu = to_arm_pmu(pmu);
/* Enable all of the perf events on hardware. */
int idx, enabled = 0;
struct cpu_hw_events *cpuc = armpmu->get_hw_events();
Expand All @@ -609,24 +622,31 @@ static void armpmu_enable(struct pmu *pmu)

static void armpmu_disable(struct pmu *pmu)
{
struct arm_pmu *armpmu = to_arm_pmu(pmu);
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,
};

static void __init armpmu_init(struct arm_pmu *armpmu)
{
atomic_set(&armpmu->active_events, 0);
mutex_init(&armpmu->reserve_mutex);

armpmu->pmu = (struct 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,
};
}

static int __init armpmu_register(struct arm_pmu *armpmu, char *name, int type)
{
armpmu_init(armpmu);
return perf_pmu_register(&armpmu->pmu, name, type);
}

/* Include the PMU-specific implementations. */
Expand Down Expand Up @@ -751,8 +771,7 @@ init_hw_perf_events(void)
pr_info("enabled with %s PMU driver, %d counters available\n",
armpmu->name, armpmu->num_events);
cpu_pmu_init(armpmu);
armpmu_init(armpmu);
perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
armpmu_register(armpmu, "cpu", PERF_TYPE_RAW);
} else {
pr_info("no hardware support available\n");
}
Expand Down

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