x86: allow machine_crash_shutdown to be replaced

This patch a llows machine_crash_shutdown to
be replaced, just like any of the other functions
in machine_ops

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

arch/x86/kernel/crash.c

@@ -25,6 +25,7 @@
 #include <asm/hpet.h>
 #include <linux/kdebug.h>
 #include <asm/smp.h>
+#include <asm/reboot.h>
 
 #include <mach_ipi.h>
 
@@ -117,7 +118,7 @@ static void nmi_shootdown_cpus(void)
 }
 #endif
 
-void machine_crash_shutdown(struct pt_regs *regs)
+void native_machine_crash_shutdown(struct pt_regs *regs)
 {
 	/* This function is only called after the system
 	 * has panicked or is otherwise in a critical state.

arch/x86/kernel/reboot.c

@@ -470,7 +470,10 @@ struct machine_ops machine_ops = {
 	.shutdown = native_machine_shutdown,
 	.emergency_restart = native_machine_emergency_restart,
 	.restart = native_machine_restart,
-	.halt = native_machine_halt
+	.halt = native_machine_halt,
+#ifdef CONFIG_KEXEC
+	.crash_shutdown = native_machine_crash_shutdown,
+#endif
 };
 
 void machine_power_off(void)
@@ -498,3 +501,9 @@ void machine_halt(void)
 	machine_ops.halt();
 }
 
+#ifdef CONFIG_KEXEC
+void machine_crash_shutdown(struct pt_regs *regs)
+{
+	machine_ops.crash_shutdown(regs);
+}
+#endif

include/asm-x86/reboot.h

@@ -15,5 +15,6 @@ struct machine_ops {
 extern struct machine_ops machine_ops;
 
 void machine_real_restart(unsigned char *code, int length);
+void native_machine_crash_shutdown(struct pt_regs *regs);
 
 #endif	/* _ASM_REBOOT_H */