2 files changed, 38 insertions, 16 deletions

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index ae9fc6c6add3..f6ab4f7f75bf 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -685,6 +685,9 @@ static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
         return 0;
 }
 
+static DEFINE_MUTEX(arm_pmu_mutex);
+static LIST_HEAD(arm_pmu_list);
+
 /*
  * PMU hardware loses all context when a CPU goes offline.
  * When a CPU is hotplugged back in, since some hardware registers are
@@ -693,12 +696,17 @@ static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
  */
 static int arm_perf_starting_cpu(unsigned int cpu)
 {
-        if (!__oprofile_cpu_pmu)
-                return 0;
-        if (!cpumask_test_cpu(cpu, &__oprofile_cpu_pmu->supported_cpus))
-                return 0;
-        if (__oprofile_cpu_pmu->reset)
-                __oprofile_cpu_pmu->reset(__oprofile_cpu_pmu);
+        struct arm_pmu *pmu;
+
+        mutex_lock(&arm_pmu_mutex);
+        list_for_each_entry(pmu, &arm_pmu_list, entry) {
+
+                if (!cpumask_test_cpu(cpu, &pmu->supported_cpus))
+                        continue;
+                if (pmu->reset)
+                        pmu->reset(pmu);
+        }
+        mutex_unlock(&arm_pmu_mutex);
         return 0;
 }
 
@@ -810,11 +818,9 @@ static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
         if (!cpu_hw_events)
                 return -ENOMEM;
 
-        err = cpuhp_setup_state_nocalls(CPUHP_AP_PERF_ARM_STARTING,
-                                        "AP_PERF_ARM_STARTING",
-                                        arm_perf_starting_cpu, NULL);
-        if (err)
-                goto out_hw_events;
+        mutex_lock(&arm_pmu_mutex);
+        list_add_tail(&cpu_pmu->entry, &arm_pmu_list);
+        mutex_unlock(&arm_pmu_mutex);
 
         err = cpu_pm_pmu_register(cpu_pmu);
         if (err)
@@ -850,8 +856,9 @@ static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
         return 0;
 
 out_unregister:
-        cpuhp_remove_state_nocalls(CPUHP_AP_PERF_ARM_STARTING);
-out_hw_events:
+        mutex_lock(&arm_pmu_mutex);
+        list_del(&cpu_pmu->entry);
+        mutex_unlock(&arm_pmu_mutex);
         free_percpu(cpu_hw_events);
         return err;
 }
@@ -859,7 +866,9 @@ out_hw_events:
 static void cpu_pmu_destroy(struct arm_pmu *cpu_pmu)
 {
         cpu_pm_pmu_unregister(cpu_pmu);
-        cpuhp_remove_state_nocalls(CPUHP_AP_PERF_ARM_STARTING);
+        mutex_lock(&arm_pmu_mutex);
+        list_del(&cpu_pmu->entry);
+        mutex_unlock(&arm_pmu_mutex);
         free_percpu(cpu_pmu->hw_events);
 }
 
@@ -1019,8 +1028,6 @@ int arm_pmu_device_probe(struct platform_device *pdev,
         if (ret)
                 goto out_destroy;
 
-        WARN(__oprofile_cpu_pmu, "%s(): missing PMU strucure for CPU-hotplug\n",
-             __func__);
         if (!__oprofile_cpu_pmu)
                 __oprofile_cpu_pmu = pmu;
 
@@ -1038,3 +1045,17 @@ out_free:
         kfree(pmu);
         return ret;
 }
+
+static int arm_pmu_hp_init(void)
+{
+        int ret;
+
+        ret = cpuhp_setup_state_nocalls(CPUHP_AP_PERF_ARM_STARTING,
+                                        "AP_PERF_ARM_STARTING",
+                                        arm_perf_starting_cpu, NULL);
+        if (ret)
+                pr_err("CPU hotplug notifier for ARM PMU could not be registered: %d\n",
+                       ret);
+        return ret;
+}
+subsys_initcall(arm_pmu_hp_init);
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index e6ed34eb2b2b..e18843809eec 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -109,6 +109,7 @@ struct arm_pmu {
         DECLARE_BITMAP(pmceid_bitmap, ARMV8_PMUV3_MAX_COMMON_EVENTS);
         struct platform_device  *plat_device;
         struct pmu_hw_events    __percpu *hw_events;
+        struct list_head        entry;
         struct notifier_block   cpu_pm_nb;
 };