[PATCH] i386: Add machine_ops interface to abstract halting and rebooting

machine_ops is an interface for the machine_* functions defined in
<linux/reboot.h>. This is intended to allow hypervisors to intercept
the reboot process, but it could be used to implement other x86
subarchtecture reboots.

Signed-off-by: Jeremy Fitzhardinge <[e-mail]>
Signed-off-by: Andi Kleen <[e-mail]>

arch/i386/kernel/apm.c

···
 #include <asm/desc.h>
 #include <asm/i8253.h>
 #include <asm/paravirt.h>
+#include <asm/reboot.h>
 
 #include "io_ports.h"
-
-extern void machine_real_restart(unsigned char *, int);
 
 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
 extern int (*console_blank_hook)(int);

arch/i386/kernel/reboot.c

···
 #include <asm/desc.h>
 #include "mach_reboot.h"
 #include <asm/reboot_fixups.h>
+#include <asm/reboot.h>
 
 /*
  * Power off function, if any
···
 EXPORT_SYMBOL(machine_real_restart);
 #endif
 
-void machine_shutdown(void)
+static void native_machine_shutdown(void)
 {
 #ifdef CONFIG_SMP
 	int reboot_cpu_id;
···
 {
 }
 
-void machine_emergency_restart(void)
+static void native_machine_emergency_restart(void)
 {
 	if (!reboot_thru_bios) {
 		if (efi_enabled) {
···
 	machine_real_restart(jump_to_bios, sizeof(jump_to_bios));
 }
 
-void machine_restart(char * __unused)
+static void native_machine_restart(char * __unused)
 {
 	machine_shutdown();
 	machine_emergency_restart();
 }
 
-void machine_halt(void)
+static void native_machine_halt(void)
 {
 }
 
-void machine_power_off(void)
+static void native_machine_power_off(void)
 {
 	if (pm_power_off) {
 		machine_shutdown();
···
 }
 
 
+struct machine_ops machine_ops = {
+	.power_off = native_machine_power_off,
+	.shutdown = native_machine_shutdown,
+	.emergency_restart = native_machine_emergency_restart,
+	.restart = native_machine_restart,
+	.halt = native_machine_halt,
+};
+
+void machine_power_off(void)
+{
+	machine_ops.power_off();
+}
+
+void machine_shutdown(void)
+{
+	machine_ops.shutdown();
+}
+
+void machine_emergency_restart(void)
+{
+	machine_ops.emergency_restart();
+}
+
+void machine_restart(char *cmd)
+{
+	machine_ops.restart(cmd);
+}
+
+void machine_halt(void)
+{
+	machine_ops.halt();
+}

include/asm-i386/reboot.h

···
+#ifndef _ASM_REBOOT_H
+#define _ASM_REBOOT_H
+
+struct pt_regs;
+
+struct machine_ops
+{
+	void (*restart)(char *cmd);
+	void (*halt)(void);
+	void (*power_off)(void);
+	void (*shutdown)(void);
+	void (*crash_shutdown)(struct pt_regs *);
+	void (*emergency_restart)(void);
+};
+
+extern struct machine_ops machine_ops;
+
+void machine_real_restart(unsigned char *code, int length);
+
+#endif	/* _ASM_REBOOT_H */