ARM: perf: add support for multiple PMUs

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>

1 files changed, 41 insertions, 22 deletions

diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index b13bf23ceba3..7f31eff00b80 100644
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -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;
@@ -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;
 
@@ -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;
@@ -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:
@@ -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;
 
         /*
@@ -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;
 
         /*
@@ -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;
@@ -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;
@@ -358,12 +367,11 @@ out:
         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;
 
@@ -397,6 +405,7 @@ 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);
 
@@ -404,7 +413,7 @@ static irqreturn_t armpmu_platform_irq(int irq, void *dev)
 }
 
 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;
@@ -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;
@@ -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;
                 }
 
@@ -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);
         }
 }
@@ -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;
 
@@ -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;
 
@@ -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);
@@ -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();
@@ -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. */
@@ -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");
         }