arm64/FP/SIMD: Convert to hotplug state machine

Install the callbacks via the state machine.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: rt@linutronix.de
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20160906170457.32393-2-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/arm64/kernel/fpsimd.c

@@ -299,28 +299,16 @@ static inline void fpsimd_pm_init(void) { }
 #endif /* CONFIG_CPU_PM */
 
 #ifdef CONFIG_HOTPLUG_CPU
-static int fpsimd_cpu_hotplug_notifier(struct notifier_block *nfb,
-				       unsigned long action,
-				       void *hcpu)
+static int fpsimd_cpu_dead(unsigned int cpu)
 {
-	unsigned int cpu = (long)hcpu;
-
-	switch (action) {
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		per_cpu(fpsimd_last_state, cpu) = NULL;
-		break;
-	}
-	return NOTIFY_OK;
+	per_cpu(fpsimd_last_state, cpu) = NULL;
+	return 0;
 }
 
-static struct notifier_block fpsimd_cpu_hotplug_notifier_block = {
-	.notifier_call = fpsimd_cpu_hotplug_notifier,
-};
-
 static inline void fpsimd_hotplug_init(void)
 {
-	register_cpu_notifier(&fpsimd_cpu_hotplug_notifier_block);
+	cpuhp_setup_state_nocalls(CPUHP_ARM64_FPSIMD_DEAD, "arm64/fpsimd:dead",
+				  NULL, fpsimd_cpu_dead);
 }
 
 #else

include/linux/cpuhotplug.h

@@ -20,6 +20,7 @@ enum cpuhp_state {
 	CPUHP_SOFTIRQ_DEAD,
 	CPUHP_NET_MVNETA_DEAD,
 	CPUHP_CPUIDLE_DEAD,
+	CPUHP_ARM64_FPSIMD_DEAD,
 	CPUHP_WORKQUEUE_PREP,
 	CPUHP_POWER_NUMA_PREPARE,
 	CPUHP_HRTIMERS_PREPARE,