ARM: perf: move active_events into struct arm_pmu

This patch moves the active_events counter into struct arm_pmu, in
preparation for supporting multiple PMUs. This also moves
pmu_reserve_mutex, as it is used to guard accesses to active_events.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

1 files changed, 20 insertions, 11 deletions

diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index 438482ff7498..9874395e7e7a 100644
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -82,6 +82,8 @@ struct arm_pmu {
         const unsigned  (*event_map)[PERF_COUNT_HW_MAX];
         u32             raw_event_mask;
         int             num_events;
+        atomic_t        active_events;
+        struct mutex    reserve_mutex;
         u64             max_period;
 };
 
@@ -454,15 +456,15 @@ armpmu_reserve_hardware(void)
         return 0;
 }
 
-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)) {
+        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();
-                mutex_unlock(&pmu_reserve_mutex);
+                mutex_unlock(pmu_reserve_mutex);
         }
 }
 
@@ -543,6 +545,7 @@ __hw_perf_event_init(struct perf_event *event)
 static int armpmu_event_init(struct perf_event *event)
 {
         int err = 0;
+        atomic_t *active_events = &armpmu->active_events;
 
         switch (event->attr.type) {
         case PERF_TYPE_RAW:
@@ -556,15 +559,14 @@ static int armpmu_event_init(struct perf_event *event)
 
         event->destroy = hw_perf_event_destroy;
 
-        if (!atomic_inc_not_zero(&active_events)) {
-                mutex_lock(&pmu_reserve_mutex);
-                if (atomic_read(&active_events) == 0) {
+        if (!atomic_inc_not_zero(active_events)) {
+                mutex_lock(&armpmu->reserve_mutex);
+                if (atomic_read(active_events) == 0)
                         err = armpmu_reserve_hardware();
-                }
 
                 if (!err)
-                        atomic_inc(&active_events);
-                mutex_unlock(&pmu_reserve_mutex);
+                        atomic_inc(active_events);
+                mutex_unlock(&armpmu->reserve_mutex);
         }
 
         if (err)
@@ -613,6 +615,12 @@ static struct pmu pmu = {
         .read           = armpmu_read,
 };
 
+static void __init armpmu_init(struct arm_pmu *armpmu)
+{
+        atomic_set(&armpmu->active_events, 0);
+        mutex_init(&armpmu->reserve_mutex);
+}
+
 /* Include the PMU-specific implementations. */
 #include "perf_event_xscale.c"
 #include "perf_event_v6.c"
@@ -718,6 +726,7 @@ init_hw_perf_events(void)
         if (armpmu) {
                 pr_info("enabled with %s PMU driver, %d counters available\n",
                         armpmu->name, armpmu->num_events);
+                armpmu_init(armpmu);
                 perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
         } else {
                 pr_info("no hardware support available\n");