Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull smp hotplug updates from Thomas Gleixner:
 "This is the next part of the hotplug rework.

   - Convert all notifiers with a priority assigned

   - Convert all CPU_STARTING/DYING notifiers

     The final removal of the STARTING/DYING infrastructure will happen
     when the merge window closes.

  Another 700 hundred line of unpenetrable maze gone :)"

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (70 commits)
  timers/core: Correct callback order during CPU hot plug
  leds/trigger/cpu: Move from CPU_STARTING to ONLINE level
  powerpc/numa: Convert to hotplug state machine
  arm/perf: Fix hotplug state machine conversion
  irqchip/armada: Avoid unused function warnings
  ARC/time: Convert to hotplug state machine
  clocksource/atlas7: Convert to hotplug state machine
  clocksource/armada-370-xp: Convert to hotplug state machine
  clocksource/exynos_mct: Convert to hotplug state machine
  clocksource/arm_global_timer: Convert to hotplug state machine
  rcu: Convert rcutree to hotplug state machine
  KVM/arm/arm64/vgic-new: Convert to hotplug state machine
  smp/cfd: Convert core to hotplug state machine
  x86/x2apic: Convert to CPU hotplug state machine
  profile: Convert to hotplug state machine
  timers/core: Convert to hotplug state machine
  hrtimer: Convert to hotplug state machine
  x86/tboot: Convert to hotplug state machine
  arm64/armv8 deprecated: Convert to hotplug state machine
  hwtracing/coresight-etm4x: Convert to hotplug state machine
  ...

1 files changed, 37 insertions, 22 deletions

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 8e4d7f590b06..6ccb994bdfcb 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -688,30 +688,29 @@ 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
  * UNKNOWN at reset, the PMU must be explicitly reset to avoid reading
  * junk values out of them.
  */
-static int cpu_pmu_notify(struct notifier_block *b, unsigned long action,
-                          void *hcpu)
+static int arm_perf_starting_cpu(unsigned int cpu)
 {
-        int cpu = (unsigned long)hcpu;
-        struct arm_pmu *pmu = container_of(b, struct arm_pmu, hotplug_nb);
-
-        if ((action & ~CPU_TASKS_FROZEN) != CPU_STARTING)
-                return NOTIFY_DONE;
-
-        if (!cpumask_test_cpu(cpu, &pmu->supported_cpus))
-                return NOTIFY_DONE;
+        struct arm_pmu *pmu;
 
-        if (pmu->reset)
-                pmu->reset(pmu);
-        else
-                return NOTIFY_DONE;
+        mutex_lock(&arm_pmu_mutex);
+        list_for_each_entry(pmu, &arm_pmu_list, entry) {
 
-        return NOTIFY_OK;
+                if (!cpumask_test_cpu(cpu, &pmu->supported_cpus))
+                        continue;
+                if (pmu->reset)
+                        pmu->reset(pmu);
+        }
+        mutex_unlock(&arm_pmu_mutex);
+        return 0;
 }
 
 #ifdef CONFIG_CPU_PM
@@ -822,10 +821,9 @@ static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
         if (!cpu_hw_events)
                 return -ENOMEM;
 
-        cpu_pmu->hotplug_nb.notifier_call = cpu_pmu_notify;
-        err = register_cpu_notifier(&cpu_pmu->hotplug_nb);
-        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)
@@ -861,8 +859,9 @@ static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
         return 0;
 
 out_unregister:
-        unregister_cpu_notifier(&cpu_pmu->hotplug_nb);
-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;
 }
@@ -870,7 +869,9 @@ out_hw_events:
 static void cpu_pmu_destroy(struct arm_pmu *cpu_pmu)
 {
         cpu_pm_pmu_unregister(cpu_pmu);
-        unregister_cpu_notifier(&cpu_pmu->hotplug_nb);
+        mutex_lock(&arm_pmu_mutex);
+        list_del(&cpu_pmu->entry);
+        mutex_unlock(&arm_pmu_mutex);
         free_percpu(cpu_pmu->hw_events);
 }
 
@@ -1061,3 +1062,17 @@ 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);