[PATCH] x86_64: Add ACPI reboot option

From: Aaron Durbin
Date: Mon Jul 16 2007 - 14:03:09 EST



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@xxxxxxxxxx>
----

This patch relies on the ACPI reboot mechanism patch.

diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt
index 6177d88..a9253bc 100644
--- a/Documentation/x86_64/boot-options.txt
+++ b/Documentation/x86_64/boot-options.txt
@@ -108,12 +108,15 @@ Idle loop

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_64/kernel/reboot.c b/arch/x86_64/kernel/reboot.c
index 7503068..239b576 100644
--- a/arch/x86_64/kernel/reboot.c
+++ b/arch/x86_64/kernel/reboot.c
@@ -9,6 +9,7 @@ #include <linux/string.h>
#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/hw_irq.h>
@@ -26,7 +27,8 @@ EXPORT_SYMBOL(pm_power_off);
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;
@@ -36,6 +38,7 @@ int reboot_force;
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)
@@ -51,6 +54,7 @@ static int __init reboot_setup(char *str
break;

case 't':
+ case 'a':
case 'b':
case 'k':
reboot_type = *str;
@@ -137,6 +141,11 @@ void machine_emergency_restart(void)

reboot_type = BOOT_KBD;
break;
+
+ case BOOT_ACPI:
+ acpi_reboot();
+ reboot_type = BOOT_KBD;
+ break;
}
}
}
-
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