um: Use generic idle loop

Signed-off-by: Richard Weinberger <richard@nod.at>
Cc: user-mode-linux-devel@lists.sourceforge.net
Link: http://lkml.kernel.org/r/1366149209-24787-1-git-send-email-richard@nod.atSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/um/Kconfig.common

@@ -12,6 +12,7 @@ config UML
 	select GENERIC_CPU_DEVICES
 	select GENERIC_IO
 	select GENERIC_CLOCKEVENTS
+	select GENERIC_IDLE_LOOP
 	select TTY # Needed for line.c
 
 config MMU

arch/um/kernel/process.c

@@ -210,33 +210,14 @@ void initial_thread_cb(void (*proc)(void *), void *arg)
 	kmalloc_ok = save_kmalloc_ok;
 }
 
-void default_idle(void)
+void arch_cpu_idle(void)
 {
 	unsigned long long nsecs;
 
-	while (1) {
-		/* endless idle loop with no priority at all */
-
-		/*
-		 * although we are an idle CPU, we do not want to
-		 * get into the scheduler unnecessarily.
-		 */
-		if (need_resched())
-			schedule();
-
-		tick_nohz_idle_enter();
-		rcu_idle_enter();
+	cpu_tasks[current_thread_info()->cpu].pid = os_getpid();
 	nsecs = disable_timer();
 	idle_sleep(nsecs);
-		rcu_idle_exit();
-		tick_nohz_idle_exit();
-	}
-}
-
-void cpu_idle(void)
-{
-	cpu_tasks[current_thread_info()->cpu].pid = os_getpid();
-	default_idle();
+	local_irq_enable();
 }
 
 int __cant_sleep(void) {