[PATCH] x86_64: Implemenent machine_emergency_restart

It is not safe to call set_cpus_allowed() in interrupt
context and disabling the apics is complicated code.
So unconditionally skip machine_shutdown in machine_emergency_reboot
on x86_64.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/x86_64/kernel/reboot.c

@@ -109,16 +109,10 @@ void machine_shutdown(void)
 	local_irq_enable();
 }
 
-void machine_restart(char * __unused)
+void machine_emergency_restart(void)
 {
 	int i;
 
-	printk("machine restart\n");
-
-	if (!reboot_force) {
-		machine_shutdown();
-	}
-
 	/* Tell the BIOS if we want cold or warm reboot */
 	*((unsigned short *)__va(0x472)) = reboot_mode;
 
@@ -143,6 +137,16 @@ void machine_restart(char * __unused)
 	}      
 }
 
+void machine_restart(char * __unused)
+{
+	printk("machine restart\n");
+
+	if (!reboot_force) {
+		machine_shutdown();
+	}
+	machine_emergency_restart();
+}
+
 void machine_halt(void)
 {
 }

include/asm-x86_64/emergency-restart.h

@@ -1,6 +1,6 @@
 #ifndef _ASM_EMERGENCY_RESTART_H
 #define _ASM_EMERGENCY_RESTART_H
 
-#include <asm-generic/emergency-restart.h>
+extern void machine_emergency_restart(void);
 
 #endif /* _ASM_EMERGENCY_RESTART_H */