[PATCH] Add emergency_restart()

When the kernel is working well and we want to restart cleanly
kernel_restart is the function to use.   But in many instances
the kernel wants to reboot when thing are expected to be working
very badly such as from panic or a software watchdog handler.

This patch adds the function emergency_restart() so that
callers can be clear what semantics they expect when calling
restart.  emergency_restart() is expected to be callable
from interrupt context and possibly reliable in even more
trying circumstances.

This is an initial generic implementation for all architectures.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/reboot.h b/include/linux/reboot.h
index 828ba4f..3b3266f 100644
--- a/include/linux/reboot.h
+++ b/include/linux/reboot.h
@@ -64,6 +64,13 @@
 extern void kernel_power_off(void);
 extern void kernel_kexec(void);
 
+/*
+ * Emergency restart, callable from an interrupt handler.
+ */
+
+extern void emergency_restart(void);
+#include <asm/emergency-restart.h>
+
 #endif
 
 #endif /* _LINUX_REBOOT_H */