arm64: Use generic idle loop

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: http://lkml.kernel.org/r/20130321215233.887563095@linutronix.de

arch/arm64/Kconfig

@@ -9,6 +9,7 @@ config ARM64
 	select CLONE_BACKWARDS
 	select COMMON_CLK
 	select GENERIC_CLOCKEVENTS
+	select GENERIC_IDLE_LOOP
 	select GENERIC_IOMAP
 	select GENERIC_IRQ_PROBE
 	select GENERIC_IRQ_SHOW

arch/arm64/kernel/process.c

@@ -84,11 +84,15 @@ EXPORT_SYMBOL_GPL(pm_power_off);
 void (*pm_restart)(const char *cmd);
 EXPORT_SYMBOL_GPL(pm_restart);
 
+void arch_cpu_idle_prepare(void)
+{
+	local_fiq_enable();
+}
 
 /*
  * This is our default idle handler.
  */
-static void default_idle(void)
+void arch_cpu_idle(void)
 {
 	/*
 	 * This should do all the clock switching and wait for interrupt
@@ -98,43 +102,6 @@ static void default_idle(void)
 	local_irq_enable();
 }
 
-/*
- * The idle thread.
- * We always respect 'hlt_counter' to prevent low power idle.
- */
-void cpu_idle(void)
-{
-	local_fiq_enable();
-
-	/* endless idle loop with no priority at all */
-	while (1) {
-		tick_nohz_idle_enter();
-		rcu_idle_enter();
-		while (!need_resched()) {
-			/*
-			 * We need to disable interrupts here to ensure
-			 * we don't miss a wakeup call.
-			 */
-			local_irq_disable();
-			if (!need_resched()) {
-				stop_critical_timings();
-				default_idle();
-				start_critical_timings();
-				/*
-				 * default_idle functions should always return
-				 * with IRQs enabled.
-				 */
-				WARN_ON(irqs_disabled());
-			} else {
-				local_irq_enable();
-			}
-		}
-		rcu_idle_exit();
-		tick_nohz_idle_exit();
-		schedule_preempt_disabled();
-	}
-}
-
 void machine_shutdown(void)
 {
 #ifdef CONFIG_SMP

arch/arm64/kernel/smp.c

@@ -216,7 +216,7 @@ asmlinkage void __cpuinit secondary_start_kernel(void)
 	/*
 	 * OK, it's off to the idle thread for us
 	 */
-	cpu_idle();
+	cpu_startup_entry(CPUHP_ONLINE);
 }
 
 void __init smp_cpus_done(unsigned int max_cpus)