kexec based hibernation -v6: kexec hibernate/resume

This patch implements kexec based hibernate/resume. This is based on the facility provided by kexec_jump. The ACPI methods are called at specified environment to conform the ACPI specification. Two new reboot commands are added to trigger hibernate/resume.

Signed-off-by Huang Ying <[email protected]>

---
 include/linux/kexec.h   |    5 +
 include/linux/reboot.h  |    2 
 include/linux/suspend.h |    9 ++
 kernel/power/disk.c     |  155 ++++++++++++++++++++++++++++++++++++++++++++++++
 kernel/sys.c            |   42 +++++++++++++
 5 files changed, 212 insertions(+), 1 deletion(-)

kernel/power/disk.c +5 -0

@@ -21,6 +21,7 @@
 #include <linux/console.h>
 #include <linux/cpu.h>
 #include <linux/freezer.h>
+#include <linux/kexec.h>
 
 #include "power.h"
 

@@ -438,6 +439,160 @@ int hibernate(void)
 	return error;
 }
 
+#ifdef CONFIG_KEXEC
+static void kexec_hibernate_power_down(void)
+{
+	switch (hibernation_mode) {

kernel/power/disk.c +5 -0

+		/* We should never get here */
+		while (1);
+		break;
+	case HIBERNATION_SHUTDOWN:
+		machine_power_off();

kernel/power/disk.c +21 -0

+
+int kexec_hibernate(struct kimage *image)
+{
+	int error;
+	int platform_mode = (hibernation_mode == HIBERNATION_PLATFORM);
+	unsigned long cmd_ret;
+
+	mutex_lock(&pm_mutex);
+
+	pm_prepare_console();
+	suspend_console();
+
+	error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
+	if (error)
+		goto Resume_console;
+
+	error = platform_start(platform_mode);
+	if (error)
+		goto Resume_console;
+
+	error = device_suspend(PMSG_FREEZE);

kernel/power/disk.c +4 -0

+	local_irq_disable();
+	/* At this point, device_suspend() has been called, but *not*
+	 * device_power_down(). We *must* device_power_down() now.
+	 * Otherwise, drivers for some devices (e.g. interrupt

kernel/power/disk.c +49 -0

+	restore_processor_state();
+
+	if (cmd_ret == KJUMP_CMD_HIBERNATE_POWER_DOWN)
+		kexec_hibernate_power_down();
+
+	platform_leave(platform_mode);
+
+	/* NOTE:  device_power_up() is just a resume() for devices
+	 * that suspended with irqs off ... no overall powerup.
+	 */
+	device_power_up();
+ Enable_irqs:
+	local_irq_enable();
+	enable_nonboot_cpus();
+ Resume_devices:
+	platform_finish(platform_mode);
+	device_resume();
+ Resume_console:
+	pm_notifier_call_chain(PM_POST_HIBERNATION);
+	resume_console();
+	pm_restore_console();
+	mutex_unlock(&pm_mutex);
+	return error;
+}
+
+int kexec_resume(struct kimage *image)
+{
+	int error;
+	int platform_mode = (hibernation_mode == HIBERNATION_PLATFORM);
+
+	mutex_lock(&pm_mutex);
+
+	pm_prepare_console();
+	suspend_console();
+
+	error = device_suspend(PMSG_PRETHAW);
+	if (error)
+		goto Resume_console;
+
+	error = platform_pre_restore(platform_mode);
+	if (error)
+		goto Resume_devices;
+
+	error = disable_nonboot_cpus();
+	if (error)
+		goto Resume_devices;
+	local_irq_disable();
+	/* At this point, device_suspend() has been called, but *not*
+	 * device_power_down(). We *must* device_power_down() now.

kernel/power/disk.c +14 -0

+	restore_processor_state();
+
+	platform_leave(platform_mode);
+
+	/* NOTE:  device_power_up() is just a resume() for devices
+	 * that suspended with irqs off ... no overall powerup.
+	 */
+	device_power_up();
+ Enable_irqs:
+	local_irq_enable();
+	enable_nonboot_cpus();
+ Resume_devices:
+	platform_restore_cleanup(platform_mode);
+	device_resume();

include/linux/suspend.h +9 -0

@@ -207,6 +207,15 @@ static inline void hibernation_set_ops(s
 static inline int hibernate(void) { return -ENOSYS; }
 #endif /* CONFIG_HIBERNATION */
 
+struct kimage;
+#if defined(CONFIG_HIBERNATION) && defined(CONFIG_KEXEC)
+extern int kexec_hibernate(struct kimage *image);
+extern int kexec_resume(struct kimage *image);
+#else
+static inline int kexec_hibernate(struct kimage *image) { return -ENOSYS; }
+static inline int kexec_resume(struct kimage *image) { return -ENOSYS; }
+#endif
+
 #ifdef CONFIG_PM_SLEEP
 void save_processor_state(void);
 void restore_processor_state(void);

kernel/sys.c +42 -0

@@ -321,6 +321,34 @@ static int kernel_kexec(unsigned long cm
 	return ret;
 }
 
+static int kernel_kexec_hibernate(void)
+{
+	int ret = -ENOSYS;
+#if defined(CONFIG_KEXEC) && defined(CONFIG_HIBERNATION)
+	struct kimage *image;
+	image = xchg(&kexec_image, NULL);
+	if (!image)
+		return -EINVAL;
+	ret = kexec_hibernate(image);
+	kimage_free(image);
+#endif
+	return ret;
+}
+
+static int kernel_kexec_resume(void)
+{
+	int ret = -ENOSYS;
+#if defined(CONFIG_KEXEC) && defined(CONFIG_HIBERNATION)
+	struct kimage *image;
+	image = xchg(&kexec_image, NULL);
+	if (!image)
+		return -EINVAL;
+	ret = kexec_resume(image);
+	kimage_free(image);
+#endif
+	return ret;
+}
+
 static void kernel_shutdown_prepare(enum system_states state)
 {
 	blocking_notifier_call_chain(&reboot_notifier_list,

@@ -442,6 +470,20 @@ asmlinkage long sys_reboot(int magic1, i
 		}
 #endif
 
+	case LINUX_REBOOT_CMD_KEXEC_HIBERNATE:
+		{
+			int ret = kernel_kexec_hibernate();
+			unlock_kernel();
+			return ret;
+		}
+
+	case LINUX_REBOOT_CMD_KEXEC_RESUME:
+		{
+			int ret = kernel_kexec_resume();
+			unlock_kernel();
+			return ret;
+		}
+
 	default:
 		unlock_kernel();
 		return -EINVAL;

include/linux/reboot.h +2 -0

@@ -33,6 +33,8 @@
 #define	LINUX_REBOOT_CMD_RESTART2	0xA1B2C3D4
 #define	LINUX_REBOOT_CMD_SW_SUSPEND	0xD000FCE2
 #define	LINUX_REBOOT_CMD_KEXEC		0x45584543
+#define LINUX_REBOOT_CMD_KEXEC_HIBERNATE 0xE4390DF3
+#define LINUX_REBOOT_CMD_KEXEC_RESUME	0xF5A41C2E
 
 
 #ifdef __KERNEL__

include/linux/kexec.h +4 -1

@@ -129,7 +129,10 @@ extern int machine_kexec_jump(struct kim
 			      unsigned long cmd);
 extern int kexec_jump(struct kimage *image, unsigned long *cmd_ret,
 		      unsigned long cmd);
-#define KJUMP_CMD_NONE 0
+#define KJUMP_CMD_NONE			0x0
+#define KJUMP_CMD_HIBERNATE_WRITE_IMAGE	0x6b630001
+#define KJUMP_CMD_HIBERNATE_POWER_DOWN	0x6b630002
+#define KJUMP_CMD_HIBERNATE_RESUME	0x6b630003
 #ifdef CONFIG_COMPAT
 extern asmlinkage long compat_sys_kexec_load(unsigned long entry,
 				unsigned long nr_segments,

Quoted 8 lines

kernel/power/disk.c +8 -0

+#ifdef CONFIG_KEXEC
+static void kexec_hibernate_power_down(void)
+{
+	switch (hibernation_mode) {
+	case HIBERNATION_TEST:
+	case HIBERNATION_TESTPROC:
+		break;
+	case HIBERNATION_REBOOT:

kernel/power/disk.c int hibernate(void) · line 455

Quoted 6 lines

kernel/power/disk.c +6 -0

+		machine_restart(NULL);
+		break;
+	case HIBERNATION_PLATFORM:
+		if (!hibernation_ops)
+			break;
+		hibernation_ops->enter();

hibernation_platform_enter() should be used here (as of the current mainline).

Quoted 10 lines

kernel/power/disk.c +10 -0

+		/* We should never get here */
+		while (1);
+		break;
+	case HIBERNATION_SHUTDOWN:
+		machine_power_off();
+		break;
+	}
+	machine_halt();
+	/*
+	 * Valid image is on the disk, if we continue we risk serious data

kernel/power/disk.c int hibernate(void) · line 470

Quoted 5 lines

kernel/power/disk.c +5 -0

+	 * corruption after resume.
+	 */
+	printk(KERN_CRIT "Please power me down manually\n");
+	while (1);
+}

Hm, what's the difference between the above function and power_down(), actually?

Quoted 26 lines

kernel/power/disk.c +26 -0

+
+int kexec_hibernate(struct kimage *image)
+{
+	int error;
+	int platform_mode = (hibernation_mode == HIBERNATION_PLATFORM);
+	unsigned long cmd_ret;
+
+	mutex_lock(&pm_mutex);
+
+	pm_prepare_console();
+	suspend_console();
+
+	error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
+	if (error)
+		goto Resume_console;
+
+	error = platform_start(platform_mode);
+	if (error)
+		goto Resume_console;
+
+	error = device_suspend(PMSG_FREEZE);
+	if (error)
+		goto Resume_console;
+
+	error = platform_pre_snapshot(platform_mode);
+	if (error)

kernel/power/disk.c int hibernate(void) · line 501

Quoted 5 lines

kernel/power/disk.c +5 -0

+		goto Resume_devices;
+
+	error = disable_nonboot_cpus();
+	if (error)
+		goto Resume_devices;

I wonder if it's viable to merge the above with hibernate() and hibernation_snapshot() somehow, to avoid code duplication?

Apart from the above, there's some new debug code to be added to disk.c in 2.6.25. It's in the ACPI test tree right now and you can get it as individual patches from:
http://www.sisk.pl/kernel/hibernation_and_suspend/2.6.24-rc2/patches/
(patches 10-12).

Please base your changes on top of that.

Quoted 8 lines · Rafael J. Wysocki

Quoted 8 lines

kernel/power/disk.c +8 -0

+#ifdef CONFIG_KEXEC
+static void kexec_hibernate_power_down(void)
+{
+	switch (hibernation_mode) {
+	case HIBERNATION_TEST:
+	case HIBERNATION_TESTPROC:
+		break;
+	case HIBERNATION_REBOOT:

Quoted 8 lines

kernel/power/disk.c int hibernate(void) · line 455

Quoted 6 lines

kernel/power/disk.c +6 -0

+		machine_restart(NULL);
+		break;
+	case HIBERNATION_PLATFORM:
+		if (!hibernation_ops)
+			break;
+		hibernation_ops->enter();

hibernation_platform_enter() should be used here (as of the current mainline).

The power_down will be called with interrupt disabled, device suspended, non-boot CPU disabled. But the latest hibernate_platform_enter calls the device_suspend, disable_nonboot_cpus etc function. So, I use hibernation_ops->enter() directly instead of hibernation_platform_enter().

Quoted 10 lines

Quoted 10 lines

kernel/power/disk.c +10 -0

+		/* We should never get here */
+		while (1);
+		break;
+	case HIBERNATION_SHUTDOWN:
+		machine_power_off();
+		break;
+	}
+	machine_halt();
+	/*
+	 * Valid image is on the disk, if we continue we risk serious data

Quoted 8 lines

kernel/power/disk.c int hibernate(void) · line 470

Quoted 5 lines

kernel/power/disk.c +5 -0

+	 * corruption after resume.
+	 */
+	printk(KERN_CRIT "Please power me down manually\n");
+	while (1);
+}

Hm, what's the difference between the above function and power_down(), actually?

Same as above.

Quoted 26 lines

Quoted 26 lines

kernel/power/disk.c +26 -0

+
+int kexec_hibernate(struct kimage *image)
+{
+	int error;
+	int platform_mode = (hibernation_mode == HIBERNATION_PLATFORM);
+	unsigned long cmd_ret;
+
+	mutex_lock(&pm_mutex);
+
+	pm_prepare_console();
+	suspend_console();
+
+	error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
+	if (error)
+		goto Resume_console;
+
+	error = platform_start(platform_mode);
+	if (error)
+		goto Resume_console;
+
+	error = device_suspend(PMSG_FREEZE);
+	if (error)
+		goto Resume_console;
+
+	error = platform_pre_snapshot(platform_mode);
+	if (error)

Quoted 8 lines

kernel/power/disk.c int hibernate(void) · line 501

Quoted 5 lines

kernel/power/disk.c +5 -0

+		goto Resume_devices;
+
+	error = disable_nonboot_cpus();
+	if (error)
+		goto Resume_devices;

I wonder if it's viable to merge the above with hibernate() and hibernation_snapshot() somehow, to avoid code duplication?

Yes. Most code are duplicated. But there is one advantage not to merge
them: power_down can called with IRQ disabled to make it possible to eliminate the freezer.

I think it is possible to merge the two implementation. I will try to do it.

Quoted 7 lines

Apart from the above, there's some new debug code to be added to disk.c in 2.6.25. It's in the ACPI test tree right now and you can get it as individual patches from:
http://www.sisk.pl/kernel/hibernation_and_suspend/2.6.24-rc2/patches/
(patches 10-12).

Please base your changes on top of that.

OK, I will do it.

Quoted 18 lines · Ying

Quoted 8 lines · Rafael J. Wysocki

Quoted 8 lines

kernel/power/disk.c +8 -0

+#ifdef CONFIG_KEXEC
+static void kexec_hibernate_power_down(void)
+{
+	switch (hibernation_mode) {
+	case HIBERNATION_TEST:
+	case HIBERNATION_TESTPROC:
+		break;
+	case HIBERNATION_REBOOT:

Quoted 8 lines

kernel/power/disk.c int hibernate(void) · line 455

Quoted 6 lines

kernel/power/disk.c +6 -0

+		machine_restart(NULL);
+		break;
+	case HIBERNATION_PLATFORM:
+		if (!hibernation_ops)
+			break;
+		hibernation_ops->enter();

hibernation_platform_enter() should be used here (as of the current mainline).

Quoted 5 lines

The power_down will be called with interrupt disabled, device suspended, non-boot CPU disabled. But the latest hibernate_platform_enter calls the device_suspend, disable_nonboot_cpus etc function. So, I use hibernation_ops->enter() directly instead of hibernation_platform_enter().

Hm, you need to call device_power_down(PMSG_SUSPEND) before hibernation_ops->enter().

Also, all of the ACPI global calls need to be carried out before that and the devices should be suspended rather than shut down in that case.

That's why hibernation_platform_enter() has been introduced, BTW.

- What is the difference between PMSG_SUSPEND and PMSG_FREEZE?

- What is the difference between PMSG_SUSPEND and PMSG_FREEZE?

Quoted 1 line · Ying

- What is the difference between PMSG_SUSPEND and PMSG_FREEZE?

SUSPEND means that the system is about to go into a low-power state, so the driver should take the appropriate action to reduce the device's power consumption. It should also stop all I/O and DMA to the device. Interrupts can remain enabled if the device is supposed to be a wakeup source; otherwise they should be disabled.

FREEZE means that the system is going to hibernate, and devices need to be quiescent (no I/O, no DMA, and no interrupts) so that an atomic memory snapshot can be captured. The driver should take the appropriate action to quiesce the device but the power level doesn't need to change.

PRETHAW means that the system is going to resume from hibernation by loading a previously-saved memory snapshot. The driver should take the appropriate action to quiesce the device (no I/O, no DMA, and no interrupts) so that the snapshot can be safely restored, but the power level doesn't need to change. The driver may also want to put the device into a special state so that the saved kernel's resume method will recognize the device has undergone a hibernation cycle and needs to be reinitialized.

Quoted 1 line · Ying

- What is the difference between PMSG_SUSPEND and PMSG_FREEZE?

SUSPEND means that the system is about to go into a low-power state, so the driver should take the appropriate action to reduce the device's power consumption. It should also stop all I/O and DMA to the device. Interrupts can remain enabled if the device is supposed to be a wakeup source; otherwise they should be disabled.

FREEZE means that the system is going to hibernate, and devices need to be quiescent (no I/O, no DMA, and no interrupts) so that an atomic memory snapshot can be captured. The driver should take the appropriate action to quiesce the device but the power level doesn't need to change.

PRETHAW means that the system is going to resume from hibernation by loading a previously-saved memory snapshot. The driver should take the appropriate action to quiesce the device (no I/O, no DMA, and no interrupts) so that the snapshot can be safely restored, but the power level doesn't need to change. The driver may also want to put the device into a special state so that the saved kernel's resume method will recognize the device has undergone a hibernation cycle and needs to be reinitialized.

Quoted 25 lines · Rafael J. Wysocki

Quoted 18 lines · Ying

Quoted 8 lines · Rafael J. Wysocki

Quoted 8 lines

kernel/power/disk.c +8 -0

+#ifdef CONFIG_KEXEC
+static void kexec_hibernate_power_down(void)
+{
+	switch (hibernation_mode) {
+	case HIBERNATION_TEST:
+	case HIBERNATION_TESTPROC:
+		break;
+	case HIBERNATION_REBOOT:

Quoted 8 lines

kernel/power/disk.c int hibernate(void) · line 455

Quoted 6 lines

kernel/power/disk.c +6 -0

+		machine_restart(NULL);
+		break;
+	case HIBERNATION_PLATFORM:
+		if (!hibernation_ops)
+			break;
+		hibernation_ops->enter();

hibernation_platform_enter() should be used here (as of the current mainline).

Quoted 5 lines

The power_down will be called with interrupt disabled, device suspended, non-boot CPU disabled. But the latest hibernate_platform_enter calls the device_suspend, disable_nonboot_cpus etc function. So, I use hibernation_ops->enter() directly instead of hibernation_platform_enter().

Quoted 7 lines

Hm, you need to call device_power_down(PMSG_SUSPEND) before hibernation_ops->enter().

Also, all of the ACPI global calls need to be carried out before that and the devices should be suspended rather than shut down in that case.

That's why hibernation_platform_enter() has been introduced, BTW.

Situation is a little different between u/swsusp and khiberantion.

u/swsusp:

platform_start();
suspend console();
device_suspend(PMSG_FREEZE);
platform_pre_snapshot();
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_FREEZE);
/* create snapshot */
device_power_up();
local_irq_enable();
enable_nonboot_cpus();
platform_finish();
device_resume();
resume_console();
/* write the image out */
hibernation_ops->start();
suspend_console();
device_suspend(PMSG_SUSPEND);
hibernation_ops->prepare();
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_SUSPEND);
hibernation_ops->enter();

khibernation:

suspend_console();
platform_start();
device_suspend(PMSG_FREEZE);
platform_pre_snapshot();
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_FREEZE);
/* jump to kexeced (hibernating) kernel */
/* in kexeced kernel */
device_power_up();
local_irq_eanble();
enable_nonboot_cpus();

device_resume();
resume_console();
/* write the image */

suspend_console();
device_suspend(PMSG_FREEZE);
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_FREEZE);
/* jump to original (hibernated) kernel */

Quoted 64 lines · Ying

Quoted 25 lines · Rafael J. Wysocki

Quoted 18 lines · Ying

Quoted 8 lines · Rafael J. Wysocki

Quoted 8 lines

kernel/power/disk.c +8 -0

+#ifdef CONFIG_KEXEC
+static void kexec_hibernate_power_down(void)
+{
+	switch (hibernation_mode) {
+	case HIBERNATION_TEST:
+	case HIBERNATION_TESTPROC:
+		break;
+	case HIBERNATION_REBOOT:

Quoted 8 lines

kernel/power/disk.c int hibernate(void) · line 455

Quoted 6 lines

kernel/power/disk.c +6 -0

+		machine_restart(NULL);
+		break;
+	case HIBERNATION_PLATFORM:
+		if (!hibernation_ops)
+			break;
+		hibernation_ops->enter();

hibernation_platform_enter() should be used here (as of the current mainline).

Quoted 5 lines

The power_down will be called with interrupt disabled, device suspended, non-boot CPU disabled. But the latest hibernate_platform_enter calls the device_suspend, disable_nonboot_cpus etc function. So, I use hibernation_ops->enter() directly instead of hibernation_platform_enter().

Quoted 7 lines

Hm, you need to call device_power_down(PMSG_SUSPEND) before hibernation_ops->enter().

Also, all of the ACPI global calls need to be carried out before that and the devices should be suspended rather than shut down in that case.

That's why hibernation_platform_enter() has been introduced, BTW.

Situation is a little different between u/swsusp and khiberantion.

u/swsusp:

platform_start();
suspend console();
device_suspend(PMSG_FREEZE);
platform_pre_snapshot();
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_FREEZE);
/* create snapshot */
device_power_up();
local_irq_enable();
enable_nonboot_cpus();
platform_finish();
device_resume();
resume_console();
/* write the image out */
hibernation_ops->start();
suspend_console();
device_suspend(PMSG_SUSPEND);
hibernation_ops->prepare();
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_SUSPEND);
hibernation_ops->enter();

khibernation:

Quoted 12 lines

suspend_console();
platform_start();
device_suspend(PMSG_FREEZE);
platform_pre_snapshot();
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_FREEZE);
/* jump to kexeced (hibernating) kernel */
/* in kexeced kernel */
device_power_up();
local_irq_eanble();
enable_nonboot_cpus();

You should call platform_finish() here, or device_resume() will not work appropriately on some systems.

However, after platform_finish() has been executed, the ACPI firmware will assume that the hibernation has been canceled, so you need to tell it that you'd like to go into the low power state after all.

Quoted 3 lines

device_resume();
resume_console();
/* write the image */

For this reason, you have to call hibernation_ops->start() once again and the other functions like in the swsusp case, in that order.

Quoted 6 lines

suspend_console();
device_suspend(PMSG_FREEZE);
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_FREEZE);
/* jump to original (hibernated) kernel */

This looks too fragile to my eyes.

Why don't you call hibernation_ops->enter() directly from the "kexeced" kernel?

Quoted 99 lines · Rafael J. Wysocki

Quoted 64 lines · Ying

Quoted 25 lines · Rafael J. Wysocki

Quoted 18 lines · Ying

Quoted 8 lines · Rafael J. Wysocki

Quoted 8 lines

(quoted diff) +8 -0

+#ifdef CONFIG_KEXEC
+static void kexec_hibernate_power_down(void)
+{
+	switch (hibernation_mode) {
+	case HIBERNATION_TEST:
+	case HIBERNATION_TESTPROC:
+		break;
+	case HIBERNATION_REBOOT:

Quoted 8 lines

Review

Quoted 6 lines

(quoted diff) +6 -0

+		machine_restart(NULL);
+		break;
+	case HIBERNATION_PLATFORM:
+		if (!hibernation_ops)
+			break;
+		hibernation_ops->enter();

hibernation_platform_enter() should be used here (as of the current mainline).

Quoted 5 lines

The power_down will be called with interrupt disabled, device suspended, non-boot CPU disabled. But the latest hibernate_platform_enter calls the device_suspend, disable_nonboot_cpus etc function. So, I use hibernation_ops->enter() directly instead of hibernation_platform_enter().

Quoted 7 lines

Hm, you need to call device_power_down(PMSG_SUSPEND) before hibernation_ops->enter().

Also, all of the ACPI global calls need to be carried out before that and the devices should be suspended rather than shut down in that case.

That's why hibernation_platform_enter() has been introduced, BTW.

Situation is a little different between u/swsusp and khiberantion.

u/swsusp:

platform_start();
suspend console();
device_suspend(PMSG_FREEZE);
platform_pre_snapshot();
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_FREEZE);
/* create snapshot */
device_power_up();
local_irq_enable();
enable_nonboot_cpus();
platform_finish();
device_resume();
resume_console();
/* write the image out */
hibernation_ops->start();
suspend_console();
device_suspend(PMSG_SUSPEND);
hibernation_ops->prepare();
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_SUSPEND);
hibernation_ops->enter();

khibernation:

Quoted 12 lines

suspend_console();
platform_start();
device_suspend(PMSG_FREEZE);
platform_pre_snapshot();
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_FREEZE);
/* jump to kexeced (hibernating) kernel */
/* in kexeced kernel */
device_power_up();
local_irq_eanble();
enable_nonboot_cpus();

You should call platform_finish() here, or device_resume() will not work appropriately on some systems.

However, after platform_finish() has been executed, the ACPI firmware will assume that the hibernation has been canceled, so you need to tell it that you'd like to go into the low power state after all.

Quoted 3 lines

device_resume();
resume_console();
/* write the image */

For this reason, you have to call hibernation_ops->start() once again and the other functions like in the swsusp case, in that order.

Quoted 6 lines

suspend_console();
device_suspend(PMSG_FREEZE);
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_FREEZE);
/* jump to original (hibernated) kernel */

Quoted 3 lines

This looks too fragile to my eyes.

Why don't you call hibernation_ops->enter() directly from the "kexeced" kernel?

I don't know whether there are ACPI global state inside Linux kernel. So I restrict all ACPI method calling in original kernel. If the ACPI global state in Linux kernel is not a issue, I can call hibernation_ops->enter() directly in the "kexeced" kernel.

Quoted 99 lines · Rafael J. Wysocki

Quoted 64 lines · Ying

Quoted 25 lines · Rafael J. Wysocki

Quoted 18 lines · Ying

Quoted 8 lines · Rafael J. Wysocki

Quoted 8 lines

(quoted diff) +8 -0

+#ifdef CONFIG_KEXEC
+static void kexec_hibernate_power_down(void)
+{
+	switch (hibernation_mode) {
+	case HIBERNATION_TEST:
+	case HIBERNATION_TESTPROC:
+		break;
+	case HIBERNATION_REBOOT:

Quoted 8 lines

Review

Quoted 6 lines

(quoted diff) +6 -0

+		machine_restart(NULL);
+		break;
+	case HIBERNATION_PLATFORM:
+		if (!hibernation_ops)
+			break;
+		hibernation_ops->enter();

hibernation_platform_enter() should be used here (as of the current mainline).

Quoted 5 lines

The power_down will be called with interrupt disabled, device suspended, non-boot CPU disabled. But the latest hibernate_platform_enter calls the device_suspend, disable_nonboot_cpus etc function. So, I use hibernation_ops->enter() directly instead of hibernation_platform_enter().

Quoted 7 lines

Hm, you need to call device_power_down(PMSG_SUSPEND) before hibernation_ops->enter().

Also, all of the ACPI global calls need to be carried out before that and the devices should be suspended rather than shut down in that case.

That's why hibernation_platform_enter() has been introduced, BTW.

Situation is a little different between u/swsusp and khiberantion.

u/swsusp:

platform_start();
suspend console();
device_suspend(PMSG_FREEZE);
platform_pre_snapshot();
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_FREEZE);
/* create snapshot */
device_power_up();
local_irq_enable();
enable_nonboot_cpus();
platform_finish();
device_resume();
resume_console();
/* write the image out */
hibernation_ops->start();
suspend_console();
device_suspend(PMSG_SUSPEND);
hibernation_ops->prepare();
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_SUSPEND);
hibernation_ops->enter();

khibernation:

Quoted 12 lines

suspend_console();
platform_start();
device_suspend(PMSG_FREEZE);
platform_pre_snapshot();
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_FREEZE);
/* jump to kexeced (hibernating) kernel */
/* in kexeced kernel */
device_power_up();
local_irq_eanble();
enable_nonboot_cpus();

You should call platform_finish() here, or device_resume() will not work appropriately on some systems.

However, after platform_finish() has been executed, the ACPI firmware will assume that the hibernation has been canceled, so you need to tell it that you'd like to go into the low power state after all.

Quoted 3 lines

device_resume();
resume_console();
/* write the image */

For this reason, you have to call hibernation_ops->start() once again and the other functions like in the swsusp case, in that order.

Quoted 6 lines

suspend_console();
device_suspend(PMSG_FREEZE);
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_FREEZE);
/* jump to original (hibernated) kernel */

Quoted 3 lines

This looks too fragile to my eyes.

Why don't you call hibernation_ops->enter() directly from the "kexeced" kernel?

I don't know whether there are ACPI global state inside Linux kernel. So I restrict all ACPI method calling in original kernel. If the ACPI global state in Linux kernel is not a issue, I can call hibernation_ops->enter() directly in the "kexeced" kernel.

Quoted 64 lines · Ying

Quoted 25 lines · Rafael J. Wysocki

Quoted 18 lines · Ying

Quoted 8 lines · Rafael J. Wysocki

Quoted 8 lines

kernel/power/disk.c +8 -0

+#ifdef CONFIG_KEXEC
+static void kexec_hibernate_power_down(void)
+{
+	switch (hibernation_mode) {
+	case HIBERNATION_TEST:
+	case HIBERNATION_TESTPROC:
+		break;
+	case HIBERNATION_REBOOT:

Quoted 8 lines

kernel/power/disk.c int hibernate(void) · line 455

Quoted 6 lines

kernel/power/disk.c +6 -0

+		machine_restart(NULL);
+		break;
+	case HIBERNATION_PLATFORM:
+		if (!hibernation_ops)
+			break;
+		hibernation_ops->enter();

hibernation_platform_enter() should be used here (as of the current mainline).

Quoted 5 lines

The power_down will be called with interrupt disabled, device suspended, non-boot CPU disabled. But the latest hibernate_platform_enter calls the device_suspend, disable_nonboot_cpus etc function. So, I use hibernation_ops->enter() directly instead of hibernation_platform_enter().

Quoted 7 lines

Hm, you need to call device_power_down(PMSG_SUSPEND) before hibernation_ops->enter().

Also, all of the ACPI global calls need to be carried out before that and the devices should be suspended rather than shut down in that case.

That's why hibernation_platform_enter() has been introduced, BTW.

Situation is a little different between u/swsusp and khiberantion.

u/swsusp:

platform_start();
suspend console();
device_suspend(PMSG_FREEZE);
platform_pre_snapshot();
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_FREEZE);
/* create snapshot */
device_power_up();
local_irq_enable();
enable_nonboot_cpus();
platform_finish();
device_resume();
resume_console();
/* write the image out */
hibernation_ops->start();
suspend_console();
device_suspend(PMSG_SUSPEND);
hibernation_ops->prepare();
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_SUSPEND);
hibernation_ops->enter();

khibernation:

Quoted 12 lines

suspend_console();
platform_start();
device_suspend(PMSG_FREEZE);
platform_pre_snapshot();
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_FREEZE);
/* jump to kexeced (hibernating) kernel */
/* in kexeced kernel */
device_power_up();
local_irq_eanble();
enable_nonboot_cpus();

You should call platform_finish() here, or device_resume() will not work appropriately on some systems.

However, after platform_finish() has been executed, the ACPI firmware will assume that the hibernation has been canceled, so you need to tell it that you'd like to go into the low power state after all.

Quoted 3 lines

device_resume();
resume_console();
/* write the image */

For this reason, you have to call hibernation_ops->start() once again and the other functions like in the swsusp case, in that order.

Quoted 6 lines

suspend_console();
device_suspend(PMSG_FREEZE);
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_FREEZE);
/* jump to original (hibernated) kernel */

This looks too fragile to my eyes.

Why don't you call hibernation_ops->enter() directly from the "kexeced" kernel?

Quoted 25 lines · Rafael J. Wysocki

Quoted 18 lines · Ying

Quoted 8 lines · Rafael J. Wysocki

Quoted 8 lines

kernel/power/disk.c +8 -0

+#ifdef CONFIG_KEXEC
+static void kexec_hibernate_power_down(void)
+{
+	switch (hibernation_mode) {
+	case HIBERNATION_TEST:
+	case HIBERNATION_TESTPROC:
+		break;
+	case HIBERNATION_REBOOT:

Quoted 8 lines

kernel/power/disk.c int hibernate(void) · line 455

Quoted 6 lines

kernel/power/disk.c +6 -0

+		machine_restart(NULL);
+		break;
+	case HIBERNATION_PLATFORM:
+		if (!hibernation_ops)
+			break;
+		hibernation_ops->enter();

hibernation_platform_enter() should be used here (as of the current mainline).

Quoted 5 lines

The power_down will be called with interrupt disabled, device suspended, non-boot CPU disabled. But the latest hibernate_platform_enter calls the device_suspend, disable_nonboot_cpus etc function. So, I use hibernation_ops->enter() directly instead of hibernation_platform_enter().

Quoted 7 lines

Hm, you need to call device_power_down(PMSG_SUSPEND) before hibernation_ops->enter().

Also, all of the ACPI global calls need to be carried out before that and the devices should be suspended rather than shut down in that case.

That's why hibernation_platform_enter() has been introduced, BTW.

Situation is a little different between u/swsusp and khiberantion.

u/swsusp:

platform_start();
suspend console();
device_suspend(PMSG_FREEZE);
platform_pre_snapshot();
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_FREEZE);
/* create snapshot */
device_power_up();
local_irq_enable();
enable_nonboot_cpus();
platform_finish();
device_resume();
resume_console();
/* write the image out */
hibernation_ops->start();
suspend_console();
device_suspend(PMSG_SUSPEND);
hibernation_ops->prepare();
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_SUSPEND);
hibernation_ops->enter();

khibernation:

suspend_console();
platform_start();
device_suspend(PMSG_FREEZE);
platform_pre_snapshot();
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_FREEZE);
/* jump to kexeced (hibernating) kernel */
/* in kexeced kernel */
device_power_up();
local_irq_eanble();
enable_nonboot_cpus();

device_resume();
resume_console();
/* write the image */

suspend_console();
device_suspend(PMSG_FREEZE);
disable_nonboot_cpus();
local_irq_disable();
device_power_down(PMSG_FREEZE);
/* jump to original (hibernated) kernel */

Quoted 18 lines · Ying

Quoted 8 lines · Rafael J. Wysocki

Quoted 8 lines

kernel/power/disk.c +8 -0

+#ifdef CONFIG_KEXEC
+static void kexec_hibernate_power_down(void)
+{
+	switch (hibernation_mode) {
+	case HIBERNATION_TEST:
+	case HIBERNATION_TESTPROC:
+		break;
+	case HIBERNATION_REBOOT:

Quoted 8 lines

kernel/power/disk.c int hibernate(void) · line 455

Quoted 6 lines

kernel/power/disk.c +6 -0

+		machine_restart(NULL);
+		break;
+	case HIBERNATION_PLATFORM:
+		if (!hibernation_ops)
+			break;
+		hibernation_ops->enter();

hibernation_platform_enter() should be used here (as of the current mainline).

Quoted 5 lines

The power_down will be called with interrupt disabled, device suspended, non-boot CPU disabled. But the latest hibernate_platform_enter calls the device_suspend, disable_nonboot_cpus etc function. So, I use hibernation_ops->enter() directly instead of hibernation_platform_enter().

Hm, you need to call device_power_down(PMSG_SUSPEND) before hibernation_ops->enter().

Also, all of the ACPI global calls need to be carried out before that and the devices should be suspended rather than shut down in that case.

That's why hibernation_platform_enter() has been introduced, BTW.

Quoted 8 lines · Rafael J. Wysocki

Quoted 8 lines

kernel/power/disk.c +8 -0

+#ifdef CONFIG_KEXEC
+static void kexec_hibernate_power_down(void)
+{
+	switch (hibernation_mode) {
+	case HIBERNATION_TEST:
+	case HIBERNATION_TESTPROC:
+		break;
+	case HIBERNATION_REBOOT:

Quoted 8 lines

kernel/power/disk.c int hibernate(void) · line 455

Quoted 6 lines

kernel/power/disk.c +6 -0

+		machine_restart(NULL);
+		break;
+	case HIBERNATION_PLATFORM:
+		if (!hibernation_ops)
+			break;
+		hibernation_ops->enter();

hibernation_platform_enter() should be used here (as of the current mainline).

The power_down will be called with interrupt disabled, device suspended, non-boot CPU disabled. But the latest hibernate_platform_enter calls the device_suspend, disable_nonboot_cpus etc function. So, I use hibernation_ops->enter() directly instead of hibernation_platform_enter().

Quoted 10 lines

Quoted 10 lines

kernel/power/disk.c +10 -0

+		/* We should never get here */
+		while (1);
+		break;
+	case HIBERNATION_SHUTDOWN:
+		machine_power_off();
+		break;
+	}
+	machine_halt();
+	/*
+	 * Valid image is on the disk, if we continue we risk serious data

Quoted 8 lines

kernel/power/disk.c int hibernate(void) · line 470

Quoted 5 lines

kernel/power/disk.c +5 -0

+	 * corruption after resume.
+	 */
+	printk(KERN_CRIT "Please power me down manually\n");
+	while (1);
+}

Hm, what's the difference between the above function and power_down(), actually?

Same as above.

Quoted 26 lines

Quoted 26 lines

kernel/power/disk.c +26 -0

+
+int kexec_hibernate(struct kimage *image)
+{
+	int error;
+	int platform_mode = (hibernation_mode == HIBERNATION_PLATFORM);
+	unsigned long cmd_ret;
+
+	mutex_lock(&pm_mutex);
+
+	pm_prepare_console();
+	suspend_console();
+
+	error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
+	if (error)
+		goto Resume_console;
+
+	error = platform_start(platform_mode);
+	if (error)
+		goto Resume_console;
+
+	error = device_suspend(PMSG_FREEZE);
+	if (error)
+		goto Resume_console;
+
+	error = platform_pre_snapshot(platform_mode);
+	if (error)

Quoted 8 lines

kernel/power/disk.c int hibernate(void) · line 501

Quoted 5 lines

kernel/power/disk.c +5 -0

+		goto Resume_devices;
+
+	error = disable_nonboot_cpus();
+	if (error)
+		goto Resume_devices;

I wonder if it's viable to merge the above with hibernate() and hibernation_snapshot() somehow, to avoid code duplication?

Yes. Most code are duplicated. But there is one advantage not to merge
them: power_down can called with IRQ disabled to make it possible to eliminate the freezer.

I think it is possible to merge the two implementation. I will try to do it.

Quoted 7 lines

Apart from the above, there's some new debug code to be added to disk.c in 2.6.25. It's in the ACPI test tree right now and you can get it as individual patches from:
http://www.sisk.pl/kernel/hibernation_and_suspend/2.6.24-rc2/patches/
(patches 10-12).

Please base your changes on top of that.

OK, I will do it.

Quoted 8 lines

kernel/power/disk.c +8 -0

+#ifdef CONFIG_KEXEC
+static void kexec_hibernate_power_down(void)
+{
+	switch (hibernation_mode) {
+	case HIBERNATION_TEST:
+	case HIBERNATION_TESTPROC:
+		break;
+	case HIBERNATION_REBOOT:

kernel/power/disk.c int hibernate(void) · line 455

Quoted 6 lines

kernel/power/disk.c +6 -0

+		machine_restart(NULL);
+		break;
+	case HIBERNATION_PLATFORM:
+		if (!hibernation_ops)
+			break;
+		hibernation_ops->enter();

hibernation_platform_enter() should be used here (as of the current mainline).

Quoted 10 lines

kernel/power/disk.c +10 -0

+		/* We should never get here */
+		while (1);
+		break;
+	case HIBERNATION_SHUTDOWN:
+		machine_power_off();
+		break;
+	}
+	machine_halt();
+	/*
+	 * Valid image is on the disk, if we continue we risk serious data

kernel/power/disk.c int hibernate(void) · line 470

Quoted 5 lines

kernel/power/disk.c +5 -0

+	 * corruption after resume.
+	 */
+	printk(KERN_CRIT "Please power me down manually\n");
+	while (1);
+}

Hm, what's the difference between the above function and power_down(), actually?

Quoted 26 lines

kernel/power/disk.c +26 -0

+
+int kexec_hibernate(struct kimage *image)
+{
+	int error;
+	int platform_mode = (hibernation_mode == HIBERNATION_PLATFORM);
+	unsigned long cmd_ret;
+
+	mutex_lock(&pm_mutex);
+
+	pm_prepare_console();
+	suspend_console();
+
+	error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
+	if (error)
+		goto Resume_console;
+
+	error = platform_start(platform_mode);
+	if (error)
+		goto Resume_console;
+
+	error = device_suspend(PMSG_FREEZE);
+	if (error)
+		goto Resume_console;
+
+	error = platform_pre_snapshot(platform_mode);
+	if (error)

kernel/power/disk.c int hibernate(void) · line 501

Quoted 5 lines

kernel/power/disk.c +5 -0

+		goto Resume_devices;
+
+	error = disable_nonboot_cpus();
+	if (error)
+		goto Resume_devices;

I wonder if it's viable to merge the above with hibernate() and hibernation_snapshot() somehow, to avoid code duplication?

Apart from the above, there's some new debug code to be added to disk.c in 2.6.25. It's in the ACPI test tree right now and you can get it as individual patches from:
http://www.sisk.pl/kernel/hibernation_and_suspend/2.6.24-rc2/patches/
(patches 10-12).

Please base your changes on top of that.

This patch implements kexec based hibernate/resume. This is based on the facility provided by kexec_jump. The ACPI methods are called at specified environment to conform the ACPI specification. Two new reboot commands are added to trigger hibernate/resume.

Signed-off-by Huang Ying <[email protected]>

---
 include/linux/kexec.h   |    5 +
 include/linux/reboot.h  |    2 
 include/linux/suspend.h |    9 ++
 kernel/power/disk.c     |  155 ++++++++++++++++++++++++++++++++++++++++++++++++
 kernel/sys.c            |   42 +++++++++++++
 5 files changed, 212 insertions(+), 1 deletion(-)

kernel/power/disk.c +5 -0

@@ -21,6 +21,7 @@
 #include <linux/console.h>
 #include <linux/cpu.h>
 #include <linux/freezer.h>
+#include <linux/kexec.h>
 
 #include "power.h"
 

@@ -438,6 +439,160 @@ int hibernate(void)
 	return error;
 }
 
+#ifdef CONFIG_KEXEC
+static void kexec_hibernate_power_down(void)
+{
+	switch (hibernation_mode) {

kernel/power/disk.c +5 -0

+		/* We should never get here */
+		while (1);
+		break;
+	case HIBERNATION_SHUTDOWN:
+		machine_power_off();

kernel/power/disk.c +21 -0

+
+int kexec_hibernate(struct kimage *image)
+{
+	int error;
+	int platform_mode = (hibernation_mode == HIBERNATION_PLATFORM);
+	unsigned long cmd_ret;
+
+	mutex_lock(&pm_mutex);
+
+	pm_prepare_console();
+	suspend_console();
+
+	error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
+	if (error)
+		goto Resume_console;
+
+	error = platform_start(platform_mode);
+	if (error)
+		goto Resume_console;
+
+	error = device_suspend(PMSG_FREEZE);

kernel/power/disk.c +4 -0

+	local_irq_disable();
+	/* At this point, device_suspend() has been called, but *not*
+	 * device_power_down(). We *must* device_power_down() now.
+	 * Otherwise, drivers for some devices (e.g. interrupt

kernel/power/disk.c +49 -0

+	restore_processor_state();
+
+	if (cmd_ret == KJUMP_CMD_HIBERNATE_POWER_DOWN)
+		kexec_hibernate_power_down();
+
+	platform_leave(platform_mode);
+
+	/* NOTE:  device_power_up() is just a resume() for devices
+	 * that suspended with irqs off ... no overall powerup.
+	 */
+	device_power_up();
+ Enable_irqs:
+	local_irq_enable();
+	enable_nonboot_cpus();
+ Resume_devices:
+	platform_finish(platform_mode);
+	device_resume();
+ Resume_console:
+	pm_notifier_call_chain(PM_POST_HIBERNATION);
+	resume_console();
+	pm_restore_console();
+	mutex_unlock(&pm_mutex);
+	return error;
+}
+
+int kexec_resume(struct kimage *image)
+{
+	int error;
+	int platform_mode = (hibernation_mode == HIBERNATION_PLATFORM);
+
+	mutex_lock(&pm_mutex);
+
+	pm_prepare_console();
+	suspend_console();
+
+	error = device_suspend(PMSG_PRETHAW);
+	if (error)
+		goto Resume_console;
+
+	error = platform_pre_restore(platform_mode);
+	if (error)
+		goto Resume_devices;
+
+	error = disable_nonboot_cpus();
+	if (error)
+		goto Resume_devices;
+	local_irq_disable();
+	/* At this point, device_suspend() has been called, but *not*
+	 * device_power_down(). We *must* device_power_down() now.

kernel/power/disk.c +14 -0

+	restore_processor_state();
+
+	platform_leave(platform_mode);
+
+	/* NOTE:  device_power_up() is just a resume() for devices
+	 * that suspended with irqs off ... no overall powerup.
+	 */
+	device_power_up();
+ Enable_irqs:
+	local_irq_enable();
+	enable_nonboot_cpus();
+ Resume_devices:
+	platform_restore_cleanup(platform_mode);
+	device_resume();

include/linux/suspend.h +9 -0

@@ -207,6 +207,15 @@ static inline void hibernation_set_ops(s
 static inline int hibernate(void) { return -ENOSYS; }
 #endif /* CONFIG_HIBERNATION */
 
+struct kimage;
+#if defined(CONFIG_HIBERNATION) && defined(CONFIG_KEXEC)
+extern int kexec_hibernate(struct kimage *image);
+extern int kexec_resume(struct kimage *image);
+#else
+static inline int kexec_hibernate(struct kimage *image) { return -ENOSYS; }
+static inline int kexec_resume(struct kimage *image) { return -ENOSYS; }
+#endif
+
 #ifdef CONFIG_PM_SLEEP
 void save_processor_state(void);
 void restore_processor_state(void);

kernel/sys.c +42 -0

@@ -321,6 +321,34 @@ static int kernel_kexec(unsigned long cm
 	return ret;
 }
 
+static int kernel_kexec_hibernate(void)
+{
+	int ret = -ENOSYS;
+#if defined(CONFIG_KEXEC) && defined(CONFIG_HIBERNATION)
+	struct kimage *image;
+	image = xchg(&kexec_image, NULL);
+	if (!image)
+		return -EINVAL;
+	ret = kexec_hibernate(image);
+	kimage_free(image);
+#endif
+	return ret;
+}
+
+static int kernel_kexec_resume(void)
+{
+	int ret = -ENOSYS;
+#if defined(CONFIG_KEXEC) && defined(CONFIG_HIBERNATION)
+	struct kimage *image;
+	image = xchg(&kexec_image, NULL);
+	if (!image)
+		return -EINVAL;
+	ret = kexec_resume(image);
+	kimage_free(image);
+#endif
+	return ret;
+}
+
 static void kernel_shutdown_prepare(enum system_states state)
 {
 	blocking_notifier_call_chain(&reboot_notifier_list,

@@ -442,6 +470,20 @@ asmlinkage long sys_reboot(int magic1, i
 		}
 #endif
 
+	case LINUX_REBOOT_CMD_KEXEC_HIBERNATE:
+		{
+			int ret = kernel_kexec_hibernate();
+			unlock_kernel();
+			return ret;
+		}
+
+	case LINUX_REBOOT_CMD_KEXEC_RESUME:
+		{
+			int ret = kernel_kexec_resume();
+			unlock_kernel();
+			return ret;
+		}
+
 	default:
 		unlock_kernel();
 		return -EINVAL;

include/linux/reboot.h +2 -0

@@ -33,6 +33,8 @@
 #define	LINUX_REBOOT_CMD_RESTART2	0xA1B2C3D4
 #define	LINUX_REBOOT_CMD_SW_SUSPEND	0xD000FCE2
 #define	LINUX_REBOOT_CMD_KEXEC		0x45584543
+#define LINUX_REBOOT_CMD_KEXEC_HIBERNATE 0xE4390DF3
+#define LINUX_REBOOT_CMD_KEXEC_RESUME	0xF5A41C2E
 
 
 #ifdef __KERNEL__

include/linux/kexec.h +4 -1

@@ -129,7 +129,10 @@ extern int machine_kexec_jump(struct kim
 			      unsigned long cmd);
 extern int kexec_jump(struct kimage *image, unsigned long *cmd_ret,
 		      unsigned long cmd);
-#define KJUMP_CMD_NONE 0
+#define KJUMP_CMD_NONE			0x0
+#define KJUMP_CMD_HIBERNATE_WRITE_IMAGE	0x6b630001
+#define KJUMP_CMD_HIBERNATE_POWER_DOWN	0x6b630002
+#define KJUMP_CMD_HIBERNATE_RESUME	0x6b630003
 #ifdef CONFIG_COMPAT
 extern asmlinkage long compat_sys_kexec_load(unsigned long entry,
 				unsigned long nr_segments,