Merge tag 'irq-core-2020-12-23' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux-2.6-microblaze.git] / drivers / gpu / drm / i915 / i915_pmu.c

diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
index 3b88cb0..d76685c 100644 (file)
--- a/drivers/gpu/drm/i915/i915_pmu.c
+++ b/drivers/gpu/drm/i915/i915_pmu.c
@@ -29,6 +29,7 @@
 #define ENGINE_SAMPLE_BITS (1 << I915_PMU_SAMPLE_BITS)
 
 static cpumask_t i915_pmu_cpumask;
+static unsigned int i915_pmu_target_cpu = -1;
 
 static u8 engine_config_sample(u64 config)
 {
@@ -428,6 +429,8 @@ static void i915_pmu_event_destroy(struct perf_event *event)
                container_of(event->pmu, typeof(*i915), pmu.base);
 
        drm_WARN_ON(&i915->drm, event->parent);
+
+       drm_dev_put(&i915->drm);
 }
 
 static int
@@ -493,8 +496,12 @@ static int i915_pmu_event_init(struct perf_event *event)
 {
        struct drm_i915_private *i915 =
                container_of(event->pmu, typeof(*i915), pmu.base);
+       struct i915_pmu *pmu = &i915->pmu;
        int ret;
 
+       if (pmu->closed)
+               return -ENODEV;
+
        if (event->attr.type != event->pmu->type)
                return -ENOENT;
 
@@ -519,8 +526,10 @@ static int i915_pmu_event_init(struct perf_event *event)
        if (ret)
                return ret;
 
-       if (!event->parent)
+       if (!event->parent) {
+               drm_dev_get(&i915->drm);
                event->destroy = i915_pmu_event_destroy;
+       }
 
        return 0;
 }
@@ -577,9 +586,16 @@ static u64 __i915_pmu_event_read(struct perf_event *event)
 
 static void i915_pmu_event_read(struct perf_event *event)
 {
+       struct drm_i915_private *i915 =
+               container_of(event->pmu, typeof(*i915), pmu.base);
        struct hw_perf_event *hwc = &event->hw;
+       struct i915_pmu *pmu = &i915->pmu;
        u64 prev, new;
 
+       if (pmu->closed) {
+               event->hw.state = PERF_HES_STOPPED;
+               return;
+       }
 again:
        prev = local64_read(&hwc->prev_count);
        new = __i915_pmu_event_read(event);
@@ -707,6 +723,13 @@ static void i915_pmu_disable(struct perf_event *event)
 
 static void i915_pmu_event_start(struct perf_event *event, int flags)
 {
+       struct drm_i915_private *i915 =
+               container_of(event->pmu, typeof(*i915), pmu.base);
+       struct i915_pmu *pmu = &i915->pmu;
+
+       if (pmu->closed)
+               return;
+
        i915_pmu_enable(event);
        event->hw.state = 0;
 }
@@ -721,6 +744,13 @@ static void i915_pmu_event_stop(struct perf_event *event, int flags)
 
 static int i915_pmu_event_add(struct perf_event *event, int flags)
 {
+       struct drm_i915_private *i915 =
+               container_of(event->pmu, typeof(*i915), pmu.base);
+       struct i915_pmu *pmu = &i915->pmu;
+
+       if (pmu->closed)
+               return -ENODEV;
+
        if (flags & PERF_EF_START)
                i915_pmu_event_start(event, flags);
 
@@ -1003,25 +1033,39 @@ static int i915_pmu_cpu_online(unsigned int cpu, struct hlist_node *node)
 static int i915_pmu_cpu_offline(unsigned int cpu, struct hlist_node *node)
 {
        struct i915_pmu *pmu = hlist_entry_safe(node, typeof(*pmu), cpuhp.node);
-       unsigned int target;
+       unsigned int target = i915_pmu_target_cpu;
 
        GEM_BUG_ON(!pmu->base.event_init);
 
+       /*
+        * Unregistering an instance generates a CPU offline event which we must
+        * ignore to avoid incorrectly modifying the shared i915_pmu_cpumask.
+        */
+       if (pmu->closed)
+               return 0;
+
        if (cpumask_test_and_clear_cpu(cpu, &i915_pmu_cpumask)) {
                target = cpumask_any_but(topology_sibling_cpumask(cpu), cpu);
+
                /* Migrate events if there is a valid target */
                if (target < nr_cpu_ids) {
                        cpumask_set_cpu(target, &i915_pmu_cpumask);
-                       perf_pmu_migrate_context(&pmu->base, cpu, target);
+                       i915_pmu_target_cpu = target;
                }
        }
 
+       if (target < nr_cpu_ids && target != pmu->cpuhp.cpu) {
+               perf_pmu_migrate_context(&pmu->base, cpu, target);
+               pmu->cpuhp.cpu = target;
+       }
+
        return 0;
 }
 
-static int i915_pmu_register_cpuhp_state(struct i915_pmu *pmu)
+static enum cpuhp_state cpuhp_slot = CPUHP_INVALID;
+
+void i915_pmu_init(void)
 {
-       enum cpuhp_state slot;
        int ret;
 
        ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
@@ -1029,27 +1073,29 @@ static int i915_pmu_register_cpuhp_state(struct i915_pmu *pmu)
                                      i915_pmu_cpu_online,
                                      i915_pmu_cpu_offline);
        if (ret < 0)
-               return ret;
+               pr_notice("Failed to setup cpuhp state for i915 PMU! (%d)\n",
+                         ret);
+       else
+               cpuhp_slot = ret;
+}
 
-       slot = ret;
-       ret = cpuhp_state_add_instance(slot, &pmu->cpuhp.node);
-       if (ret) {
-               cpuhp_remove_multi_state(slot);
-               return ret;
-       }
+void i915_pmu_exit(void)
+{
+       if (cpuhp_slot != CPUHP_INVALID)
+               cpuhp_remove_multi_state(cpuhp_slot);
+}
 
-       pmu->cpuhp.slot = slot;
-       return 0;
+static int i915_pmu_register_cpuhp_state(struct i915_pmu *pmu)
+{
+       if (cpuhp_slot == CPUHP_INVALID)
+               return -EINVAL;
+
+       return cpuhp_state_add_instance(cpuhp_slot, &pmu->cpuhp.node);
 }
 
 static void i915_pmu_unregister_cpuhp_state(struct i915_pmu *pmu)
 {
-       struct drm_i915_private *i915 = container_of(pmu, typeof(*i915), pmu);
-
-       drm_WARN_ON(&i915->drm, pmu->cpuhp.slot == CPUHP_INVALID);
-       drm_WARN_ON(&i915->drm, cpuhp_state_remove_instance(pmu->cpuhp.slot, &pmu->cpuhp.node));
-       cpuhp_remove_multi_state(pmu->cpuhp.slot);
-       pmu->cpuhp.slot = CPUHP_INVALID;
+       cpuhp_state_remove_instance(cpuhp_slot, &pmu->cpuhp.node);
 }
 
 static bool is_igp(struct drm_i915_private *i915)
@@ -1083,7 +1129,7 @@ void i915_pmu_register(struct drm_i915_private *i915)
        spin_lock_init(&pmu->lock);
        hrtimer_init(&pmu->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
        pmu->timer.function = i915_sample;
-       pmu->cpuhp.slot = CPUHP_INVALID;
+       pmu->cpuhp.cpu = -1;
 
        if (!is_igp(i915)) {
                pmu->name = kasprintf(GFP_KERNEL,
@@ -1150,7 +1196,13 @@ void i915_pmu_unregister(struct drm_i915_private *i915)
        if (!pmu->base.event_init)
                return;
 
-       drm_WARN_ON(&i915->drm, pmu->enable);
+       /*
+        * "Disconnect" the PMU callbacks - since all are atomic synchronize_rcu
+        * ensures all currently executing ones will have exited before we
+        * proceed with unregistration.
+        */
+       pmu->closed = true;
+       synchronize_rcu();
 
        hrtimer_cancel(&pmu->timer);