2 files changed, 79 insertions, 6 deletions

diff --git a/drivers/perf/riscv_pmu.c b/drivers/perf/riscv_pmu.c
index b2b8d2074ed0..2c961839903d 100644
--- a/drivers/perf/riscv_pmu.c
+++ b/drivers/perf/riscv_pmu.c
@@ -121,7 +121,7 @@ u64 riscv_pmu_event_update(struct perf_event *event)
 	return delta;
 }
 
-static void riscv_pmu_stop(struct perf_event *event, int flags)
+void riscv_pmu_stop(struct perf_event *event, int flags)
 {
 	struct hw_perf_event *hwc = &event->hw;
 	struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
@@ -175,7 +175,7 @@ int riscv_pmu_event_set_period(struct perf_event *event)
 	return overflow;
 }
 
-static void riscv_pmu_start(struct perf_event *event, int flags)
+void riscv_pmu_start(struct perf_event *event, int flags)
 {
 	struct hw_perf_event *hwc = &event->hw;
 	struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index dca3537a8dcc..adc910e0f1e2 100644
--- a/drivers/perf/riscv_pmu_sbi.c
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -17,6 +17,7 @@
 #include <linux/irqdomain.h>
 #include <linux/of_irq.h>
 #include <linux/of.h>
+#include <linux/cpu_pm.h>
 
 #include <asm/sbi.h>
 #include <asm/hwcap.h>
@@ -693,6 +694,73 @@ static int pmu_sbi_setup_irqs(struct riscv_pmu *pmu, struct platform_device *pde
 	return 0;
 }
 
+#ifdef CONFIG_CPU_PM
+static int riscv_pm_pmu_notify(struct notifier_block *b, unsigned long cmd,
+				void *v)
+{
+	struct riscv_pmu *rvpmu = container_of(b, struct riscv_pmu, riscv_pm_nb);
+	struct cpu_hw_events *cpuc = this_cpu_ptr(rvpmu->hw_events);
+	int enabled = bitmap_weight(cpuc->used_hw_ctrs, RISCV_MAX_COUNTERS);
+	struct perf_event *event;
+	int idx;
+
+	if (!enabled)
+		return NOTIFY_OK;
+
+	for (idx = 0; idx < RISCV_MAX_COUNTERS; idx++) {
+		event = cpuc->events[idx];
+		if (!event)
+			continue;
+
+		switch (cmd) {
+		case CPU_PM_ENTER:
+			/*
+			 * Stop and update the counter
+			 */
+			riscv_pmu_stop(event, PERF_EF_UPDATE);
+			break;
+		case CPU_PM_EXIT:
+		case CPU_PM_ENTER_FAILED:
+			/*
+			 * Restore and enable the counter.
+			 *
+			 * Requires RCU read locking to be functional,
+			 * wrap the call within RCU_NONIDLE to make the
+			 * RCU subsystem aware this cpu is not idle from
+			 * an RCU perspective for the riscv_pmu_start() call
+			 * duration.
+			 */
+			RCU_NONIDLE(riscv_pmu_start(event, PERF_EF_RELOAD));
+			break;
+		default:
+			break;
+		}
+	}
+
+	return NOTIFY_OK;
+}
+
+static int riscv_pm_pmu_register(struct riscv_pmu *pmu)
+{
+	pmu->riscv_pm_nb.notifier_call = riscv_pm_pmu_notify;
+	return cpu_pm_register_notifier(&pmu->riscv_pm_nb);
+}
+
+static void riscv_pm_pmu_unregister(struct riscv_pmu *pmu)
+{
+	cpu_pm_unregister_notifier(&pmu->riscv_pm_nb);
+}
+#else
+static inline int riscv_pm_pmu_register(struct riscv_pmu *pmu) { return 0; }
+static inline void riscv_pm_pmu_unregister(struct riscv_pmu *pmu) { }
+#endif
+
+static void riscv_pmu_destroy(struct riscv_pmu *pmu)
+{
+	riscv_pm_pmu_unregister(pmu);
+	cpuhp_state_remove_instance(CPUHP_AP_PERF_RISCV_STARTING, &pmu->node);
+}
+
 static int pmu_sbi_device_probe(struct platform_device *pdev)
 {
 	struct riscv_pmu *pmu = NULL;
@@ -733,14 +801,19 @@ static int pmu_sbi_device_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	ret = riscv_pm_pmu_register(pmu);
+	if (ret)
+		goto out_unregister;
+
 	ret = perf_pmu_register(&pmu->pmu, "cpu", PERF_TYPE_RAW);
-	if (ret) {
-		cpuhp_state_remove_instance(CPUHP_AP_PERF_RISCV_STARTING, &pmu->node);
-		return ret;
-	}
+	if (ret)
+		goto out_unregister;
 
 	return 0;
 
+out_unregister:
+	riscv_pmu_destroy(pmu);
+
 out_free:
 	kfree(pmu);
 	return ret;