x86: add ACPI reboot option
Add the ability to reboot an x86_64 based machine using the RESET_REG in the
FADT ACPI table.
Signed-off-by: Aaron Durbin <adurbin@google.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt
index 9453118..d7a3332 100644
--- a/Documentation/x86_64/boot-options.txt
+++ b/Documentation/x86_64/boot-options.txt
@@ -110,12 +110,15 @@
Rebooting
- reboot=b[ios] | t[riple] | k[bd] [, [w]arm | [c]old]
+ reboot=b[ios] | t[riple] | k[bd] | a[cpi] [, [w]arm | [c]old]
bios Use the CPU reboot vector for warm reset
warm Don't set the cold reboot flag
cold Set the cold reboot flag
triple Force a triple fault (init)
kbd Use the keyboard controller. cold reset (default)
+ acpi Use the ACPI RESET_REG in the FADT. If ACPI is not configured or the
+ ACPI reset does not work, the reboot path attempts the reset using
+ the keyboard controller.
Using warm reset will be much faster especially on big memory
systems because the BIOS will not go through the memory check.
diff --git a/arch/x86/kernel/reboot_64.c b/arch/x86/kernel/reboot_64.c
index 53620a9..307f996 100644
--- a/arch/x86/kernel/reboot_64.c
+++ b/arch/x86/kernel/reboot_64.c
@@ -9,6 +9,7 @@
#include <linux/pm.h>
#include <linux/kdebug.h>
#include <linux/sched.h>
+#include <acpi/reboot.h>
#include <asm/io.h>
#include <asm/delay.h>
#include <asm/desc.h>
@@ -29,7 +30,8 @@
static long no_idt[3];
static enum {
BOOT_TRIPLE = 't',
- BOOT_KBD = 'k'
+ BOOT_KBD = 'k',
+ BOOT_ACPI = 'a'
} reboot_type = BOOT_KBD;
static int reboot_mode = 0;
int reboot_force;
@@ -39,6 +41,7 @@
cold Set the cold reboot flag
triple Force a triple fault (init)
kbd Use the keyboard controller. cold reset (default)
+ acpi Use the RESET_REG in the FADT
force Avoid anything that could hang.
*/
static int __init reboot_setup(char *str)
@@ -54,6 +57,7 @@
break;
case 't':
+ case 'a':
case 'b':
case 'k':
reboot_type = *str;
@@ -146,6 +150,11 @@
reboot_type = BOOT_KBD;
break;
+
+ case BOOT_ACPI:
+ acpi_reboot();
+ reboot_type = BOOT_KBD;
+ break;
}
}
}