1 files changed, 28 insertions, 29 deletions

diff --git a/drivers/bus/arm-ccn.c b/drivers/bus/arm-ccn.c
index acc3eb542c74..97a9185af433 100644
--- a/drivers/bus/arm-ccn.c
+++ b/drivers/bus/arm-ccn.c
@@ -167,7 +167,7 @@ struct arm_ccn_dt {
         struct hrtimer hrtimer;
 
         cpumask_t cpu;
-        struct notifier_block cpu_nb;
+        struct list_head entry;
 
         struct pmu pmu;
 };
@@ -189,6 +189,8 @@ struct arm_ccn {
         struct arm_ccn_dt dt;
 };
 
+static DEFINE_MUTEX(arm_ccn_mutex);
+static LIST_HEAD(arm_ccn_list);
 
 static int arm_ccn_node_to_xp(int node)
 {
@@ -1171,30 +1173,27 @@ static enum hrtimer_restart arm_ccn_pmu_timer_handler(struct hrtimer *hrtimer)
 }
 
 
-static int arm_ccn_pmu_cpu_notifier(struct notifier_block *nb,
-                unsigned long action, void *hcpu)
+static int arm_ccn_pmu_offline_cpu(unsigned int cpu)
 {
-        struct arm_ccn_dt *dt = container_of(nb, struct arm_ccn_dt, cpu_nb);
-        struct arm_ccn *ccn = container_of(dt, struct arm_ccn, dt);
-        unsigned int cpu = (long)hcpu; /* for (long) see kernel/cpu.c */
+        struct arm_ccn_dt *dt;
         unsigned int target;
 
-        switch (action & ~CPU_TASKS_FROZEN) {
-        case CPU_DOWN_PREPARE:
+        mutex_lock(&arm_ccn_mutex);
+        list_for_each_entry(dt, &arm_ccn_list, entry) {
+                struct arm_ccn *ccn = container_of(dt, struct arm_ccn, dt);
+
                 if (!cpumask_test_and_clear_cpu(cpu, &dt->cpu))
-                        break;
+                        continue;
                 target = cpumask_any_but(cpu_online_mask, cpu);
                 if (target >= nr_cpu_ids)
-                        break;
+                        continue;
                 perf_pmu_migrate_context(&dt->pmu, cpu, target);
                 cpumask_set_cpu(target, &dt->cpu);
                 if (ccn->irq)
                         WARN_ON(irq_set_affinity_hint(ccn->irq, &dt->cpu) != 0);
-        default:
-                break;
         }
-
-        return NOTIFY_OK;
+        mutex_unlock(&arm_ccn_mutex);
+        return 0;
 }
 
 
@@ -1266,16 +1265,6 @@ static int arm_ccn_pmu_init(struct arm_ccn *ccn)
         /* Pick one CPU which we will use to collect data from CCN... */
         cpumask_set_cpu(smp_processor_id(), &ccn->dt.cpu);
 
-        /*
-         * ... and change the selection when it goes offline. Priority is
-         * picked to have a chance to migrate events before perf is notified.
-         */
-        ccn->dt.cpu_nb.notifier_call = arm_ccn_pmu_cpu_notifier;
-        ccn->dt.cpu_nb.priority = CPU_PRI_PERF + 1,
-        err = register_cpu_notifier(&ccn->dt.cpu_nb);
-        if (err)
-                goto error_cpu_notifier;
-
         /* Also make sure that the overflow interrupt is handled by this CPU */
         if (ccn->irq) {
                 err = irq_set_affinity_hint(ccn->irq, &ccn->dt.cpu);
@@ -1289,12 +1278,13 @@ static int arm_ccn_pmu_init(struct arm_ccn *ccn)
         if (err)
                 goto error_pmu_register;
 
+        mutex_lock(&arm_ccn_mutex);
+        list_add(&ccn->dt.entry, &arm_ccn_list);
+        mutex_unlock(&arm_ccn_mutex);
         return 0;
 
 error_pmu_register:
 error_set_affinity:
-        unregister_cpu_notifier(&ccn->dt.cpu_nb);
-error_cpu_notifier:
         ida_simple_remove(&arm_ccn_pmu_ida, ccn->dt.id);
         for (i = 0; i < ccn->num_xps; i++)
                 writel(0, ccn->xp[i].base + CCN_XP_DT_CONTROL);
@@ -1306,9 +1296,12 @@ static void arm_ccn_pmu_cleanup(struct arm_ccn *ccn)
 {
         int i;
 
+        mutex_lock(&arm_ccn_mutex);
+        list_del(&ccn->dt.entry);
+        mutex_unlock(&arm_ccn_mutex);
+
         if (ccn->irq)
                 irq_set_affinity_hint(ccn->irq, NULL);
-        unregister_cpu_notifier(&ccn->dt.cpu_nb);
         for (i = 0; i < ccn->num_xps; i++)
                 writel(0, ccn->xp[i].base + CCN_XP_DT_CONTROL);
         writel(0, ccn->dt.base + CCN_DT_PMCR);
@@ -1316,7 +1309,6 @@ static void arm_ccn_pmu_cleanup(struct arm_ccn *ccn)
         ida_simple_remove(&arm_ccn_pmu_ida, ccn->dt.id);
 }
 
-
 static int arm_ccn_for_each_valid_region(struct arm_ccn *ccn,
                 int (*callback)(struct arm_ccn *ccn, int region,
                 void __iomem *base, u32 type, u32 id))
@@ -1533,7 +1525,13 @@ static struct platform_driver arm_ccn_driver = {
 
 static int __init arm_ccn_init(void)
 {
-        int i;
+        int i, ret;
+
+        ret = cpuhp_setup_state_nocalls(CPUHP_AP_PERF_ARM_CCN_ONLINE,
+                                        "AP_PERF_ARM_CCN_ONLINE", NULL,
+                                        arm_ccn_pmu_offline_cpu);
+        if (ret)
+                return ret;
 
         for (i = 0; i < ARRAY_SIZE(arm_ccn_pmu_events); i++)
                 arm_ccn_pmu_events_attrs[i] = &arm_ccn_pmu_events[i].attr.attr;
@@ -1543,6 +1541,7 @@ static int __init arm_ccn_init(void)
 
 static void __exit arm_ccn_exit(void)
 {
+        cpuhp_remove_state_nocalls(CPUHP_AP_PERF_ARM_CCN_ONLINE);
         platform_driver_unregister(&arm_ccn_driver);
 }