Don't enable interrupt unconditionally in reboot path

When they were disabled before (e.g. after a panic) it's better
to keep them off, otherwise followon panics can happen from timer
interrupt handlers etc.

Drawback is that pageup in the console won't work anymore though.

Signed-off-by: Andi Kleen <ak@suse.de>

Index: linux/arch/x86_64/kernel/reboot.c
===================================================================
--- linux.orig/arch/x86_64/kernel/reboot.c
+++ linux/arch/x86_64/kernel/reboot.c
@@ -77,6 +77,7 @@ static inline void kb_wait(void)
 
 void machine_shutdown(void)
 {
+	unsigned long flags;
 	/* Stop the cpus and apics */
 #ifdef CONFIG_SMP
 	int reboot_cpu_id;
@@ -98,7 +99,7 @@ void machine_shutdown(void)
 	smp_send_stop();
 #endif
 
-	local_irq_disable();
+	local_irq_save(flags);
 
 #ifndef CONFIG_SMP
 	disable_local_APIC();
@@ -106,7 +107,7 @@ void machine_shutdown(void)
 
 	disable_IO_APIC();
 
-	local_irq_enable();
+	local_irq_restore(flags);
 }
 
 void machine_emergency_restart(void)
Index: linux/arch/x86_64/kernel/smp.c
===================================================================
--- linux.orig/arch/x86_64/kernel/smp.c
+++ linux/arch/x86_64/kernel/smp.c
@@ -450,13 +450,14 @@ int smp_call_function (void (*func) (voi
 
 void smp_stop_cpu(void)
 {
+	unsigned long flags;
 	/*
 	 * Remove this CPU:
 	 */
 	cpu_clear(smp_processor_id(), cpu_online_map);
-	local_irq_disable();
+	local_irq_save(flags);
 	disable_local_APIC();
-	local_irq_enable(); 
+	local_irq_restore(flags);
 }
 
 static void smp_really_stop_cpu(void *dummy)