1 files changed, 955 insertions, 0 deletions

diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
new file mode 100644
index 000000000000..81d2e7464893
--- /dev/null
+++ b/kernel/power/hibernate.c
@@ -0,0 +1,955 @@
+/*
+ * kernel/power/hibernate.c - Hibernation (a.k.a suspend-to-disk) support.
+ *
+ * Copyright (c) 2003 Patrick Mochel
+ * Copyright (c) 2003 Open Source Development Lab
+ * Copyright (c) 2004 Pavel Machek <pavel@suse.cz>
+ * Copyright (c) 2009 Rafael J. Wysocki, Novell Inc.
+ *
+ * This file is released under the GPLv2.
+ */
+
+#include <linux/suspend.h>
+#include <linux/syscalls.h>
+#include <linux/reboot.h>
+#include <linux/string.h>
+#include <linux/device.h>
+#include <linux/kmod.h>
+#include <linux/delay.h>
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/pm.h>
+#include <linux/console.h>
+#include <linux/cpu.h>
+#include <linux/freezer.h>
+#include <scsi/scsi_scan.h>
+#include <asm/suspend.h>
+
+#include "power.h"
+
+
+static int noresume = 0;
+static char resume_file[256] = CONFIG_PM_STD_PARTITION;
+dev_t swsusp_resume_device;
+sector_t swsusp_resume_block;
+
+enum {
+        HIBERNATION_INVALID,
+        HIBERNATION_PLATFORM,
+        HIBERNATION_TEST,
+        HIBERNATION_TESTPROC,
+        HIBERNATION_SHUTDOWN,
+        HIBERNATION_REBOOT,
+        /* keep last */
+        __HIBERNATION_AFTER_LAST
+};
+#define HIBERNATION_MAX (__HIBERNATION_AFTER_LAST-1)
+#define HIBERNATION_FIRST (HIBERNATION_INVALID + 1)
+
+static int hibernation_mode = HIBERNATION_SHUTDOWN;
+
+static struct platform_hibernation_ops *hibernation_ops;
+
+/**
+ * hibernation_set_ops - set the global hibernate operations
+ * @ops: the hibernation operations to use in subsequent hibernation transitions
+ */
+
+void hibernation_set_ops(struct platform_hibernation_ops *ops)
+{
+        if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
+            && ops->prepare && ops->finish && ops->enter && ops->pre_restore
+            && ops->restore_cleanup)) {
+                WARN_ON(1);
+                return;
+        }
+        mutex_lock(&pm_mutex);
+        hibernation_ops = ops;
+        if (ops)
+                hibernation_mode = HIBERNATION_PLATFORM;
+        else if (hibernation_mode == HIBERNATION_PLATFORM)
+                hibernation_mode = HIBERNATION_SHUTDOWN;
+
+        mutex_unlock(&pm_mutex);
+}
+
+static bool entering_platform_hibernation;
+
+bool system_entering_hibernation(void)
+{
+        return entering_platform_hibernation;
+}
+EXPORT_SYMBOL(system_entering_hibernation);
+
+#ifdef CONFIG_PM_DEBUG
+static void hibernation_debug_sleep(void)
+{
+        printk(KERN_INFO "hibernation debug: Waiting for 5 seconds.\n");
+        mdelay(5000);
+}
+
+static int hibernation_testmode(int mode)
+{
+        if (hibernation_mode == mode) {
+                hibernation_debug_sleep();
+                return 1;
+        }
+        return 0;
+}
+
+static int hibernation_test(int level)
+{
+        if (pm_test_level == level) {
+                hibernation_debug_sleep();
+                return 1;
+        }
+        return 0;
+}
+#else /* !CONFIG_PM_DEBUG */
+static int hibernation_testmode(int mode) { return 0; }
+static int hibernation_test(int level) { return 0; }
+#endif /* !CONFIG_PM_DEBUG */
+
+/**
+ *      platform_begin - tell the platform driver that we're starting
+ *      hibernation
+ */
+
+static int platform_begin(int platform_mode)
+{
+        return (platform_mode && hibernation_ops) ?
+                hibernation_ops->begin() : 0;
+}
+
+/**
+ *      platform_end - tell the platform driver that we've entered the
+ *      working state
+ */
+
+static void platform_end(int platform_mode)
+{
+        if (platform_mode && hibernation_ops)
+                hibernation_ops->end();
+}
+
+/**
+ *      platform_pre_snapshot - prepare the machine for hibernation using the
+ *      platform driver if so configured and return an error code if it fails
+ */
+
+static int platform_pre_snapshot(int platform_mode)
+{
+        return (platform_mode && hibernation_ops) ?
+                hibernation_ops->pre_snapshot() : 0;
+}
+
+/**
+ *      platform_leave - prepare the machine for switching to the normal mode
+ *      of operation using the platform driver (called with interrupts disabled)
+ */
+
+static void platform_leave(int platform_mode)
+{
+        if (platform_mode && hibernation_ops)
+                hibernation_ops->leave();
+}
+
+/**
+ *      platform_finish - switch the machine to the normal mode of operation
+ *      using the platform driver (must be called after platform_prepare())
+ */
+
+static void platform_finish(int platform_mode)
+{
+        if (platform_mode && hibernation_ops)
+                hibernation_ops->finish();
+}
+
+/**
+ *      platform_pre_restore - prepare the platform for the restoration from a
+ *      hibernation image.  If the restore fails after this function has been
+ *      called, platform_restore_cleanup() must be called.
+ */
+
+static int platform_pre_restore(int platform_mode)
+{
+        return (platform_mode && hibernation_ops) ?
+                hibernation_ops->pre_restore() : 0;
+}
+
+/**
+ *      platform_restore_cleanup - switch the platform to the normal mode of
+ *      operation after a failing restore.  If platform_pre_restore() has been
+ *      called before the failing restore, this function must be called too,
+ *      regardless of the result of platform_pre_restore().
+ */
+
+static void platform_restore_cleanup(int platform_mode)
+{
+        if (platform_mode && hibernation_ops)
+                hibernation_ops->restore_cleanup();
+}
+
+/**
+ *      platform_recover - recover the platform from a failure to suspend
+ *      devices.
+ */
+
+static void platform_recover(int platform_mode)
+{
+        if (platform_mode && hibernation_ops && hibernation_ops->recover)
+                hibernation_ops->recover();
+}
+
+/**
+ *      create_image - freeze devices that need to be frozen with interrupts
+ *      off, create the hibernation image and thaw those devices.  Control
+ *      reappears in this routine after a restore.
+ */
+
+static int create_image(int platform_mode)
+{
+        int error;
+
+        error = arch_prepare_suspend();
+        if (error)
+                return error;
+
+        /* At this point, dpm_suspend_start() has been called, but *not*
+         * dpm_suspend_noirq(). We *must* call dpm_suspend_noirq() now.
+         * Otherwise, drivers for some devices (e.g. interrupt controllers)
+         * become desynchronized with the actual state of the hardware
+         * at resume time, and evil weirdness ensues.
+         */
+        error = dpm_suspend_noirq(PMSG_FREEZE);
+        if (error) {
+                printk(KERN_ERR "PM: Some devices failed to power down, "
+                        "aborting hibernation\n");
+                return error;
+        }
+
+        error = platform_pre_snapshot(platform_mode);
+        if (error || hibernation_test(TEST_PLATFORM))
+                goto Platform_finish;
+
+        error = disable_nonboot_cpus();
+        if (error || hibernation_test(TEST_CPUS)
+            || hibernation_testmode(HIBERNATION_TEST))
+                goto Enable_cpus;
+
+        local_irq_disable();
+
+        error = sysdev_suspend(PMSG_FREEZE);
+        if (error) {
+                printk(KERN_ERR "PM: Some system devices failed to power down, "
+                        "aborting hibernation\n");
+                goto Enable_irqs;
+        }
+
+        if (hibernation_test(TEST_CORE))
+                goto Power_up;
+
+        in_suspend = 1;
+        save_processor_state();
+        error = swsusp_arch_suspend();
+        if (error)
+                printk(KERN_ERR "PM: Error %d creating hibernation image\n",
+                        error);
+        /* Restore control flow magically appears here */
+        restore_processor_state();
+        if (!in_suspend)
+                platform_leave(platform_mode);
+
+ Power_up:
+        sysdev_resume();
+        /* NOTE:  dpm_resume_noirq() is just a resume() for devices
+         * that suspended with irqs off ... no overall powerup.
+         */
+
+ Enable_irqs:
+        local_irq_enable();
+
+ Enable_cpus:
+        enable_nonboot_cpus();
+
+ Platform_finish:
+        platform_finish(platform_mode);
+
+        dpm_resume_noirq(in_suspend ?
+                (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
+
+        return error;
+}
+
+/**
+ *      hibernation_snapshot - quiesce devices and create the hibernation
+ *      snapshot image.
+ *      @platform_mode - if set, use the platform driver, if available, to
+ *                       prepare the platform firmware for the power transition.
+ *
+ *      Must be called with pm_mutex held
+ */
+
+int hibernation_snapshot(int platform_mode)
+{
+        int error;
+
+        error = platform_begin(platform_mode);
+        if (error)
+                return error;
+
+        /* Free memory before shutting down devices. */
+        error = swsusp_shrink_memory();
+        if (error)
+                goto Close;
+
+        suspend_console();
+        error = dpm_suspend_start(PMSG_FREEZE);
+        if (error)
+                goto Recover_platform;
+
+        if (hibernation_test(TEST_DEVICES))
+                goto Recover_platform;
+
+        error = create_image(platform_mode);
+        /* Control returns here after successful restore */
+
+ Resume_devices:
+        dpm_resume_end(in_suspend ?
+                (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
+        resume_console();
+ Close:
+        platform_end(platform_mode);
+        return error;
+
+ Recover_platform:
+        platform_recover(platform_mode);
+        goto Resume_devices;
+}
+
+/**
+ *      resume_target_kernel - prepare devices that need to be suspended with
+ *      interrupts off, restore the contents of highmem that have not been
+ *      restored yet from the image and run the low level code that will restore
+ *      the remaining contents of memory and switch to the just restored target
+ *      kernel.
+ */
+
+static int resume_target_kernel(bool platform_mode)
+{
+        int error;
+
+        error = dpm_suspend_noirq(PMSG_QUIESCE);
+        if (error) {
+                printk(KERN_ERR "PM: Some devices failed to power down, "
+                        "aborting resume\n");
+                return error;
+        }
+
+        error = platform_pre_restore(platform_mode);
+        if (error)
+                goto Cleanup;
+
+        error = disable_nonboot_cpus();
+        if (error)
+                goto Enable_cpus;
+
+        local_irq_disable();
+
+        error = sysdev_suspend(PMSG_QUIESCE);
+        if (error)
+                goto Enable_irqs;
+
+        /* We'll ignore saved state, but this gets preempt count (etc) right */
+        save_processor_state();
+        error = restore_highmem();
+        if (!error) {
+                error = swsusp_arch_resume();
+                /*
+                 * The code below is only ever reached in case of a failure.
+                 * Otherwise execution continues at place where
+                 * swsusp_arch_suspend() was called
+                 */
+                BUG_ON(!error);
+                /* This call to restore_highmem() undos the previous one */
+                restore_highmem();
+        }
+        /*
+         * The only reason why swsusp_arch_resume() can fail is memory being
+         * very tight, so we have to free it as soon as we can to avoid
+         * subsequent failures
+         */
+        swsusp_free();
+        restore_processor_state();
+        touch_softlockup_watchdog();
+
+        sysdev_resume();
+
+ Enable_irqs:
+        local_irq_enable();
+
+ Enable_cpus:
+        enable_nonboot_cpus();
+
+ Cleanup:
+        platform_restore_cleanup(platform_mode);
+
+        dpm_resume_noirq(PMSG_RECOVER);
+
+        return error;
+}
+
+/**
+ *      hibernation_restore - quiesce devices and restore the hibernation
+ *      snapshot image.  If successful, control returns in hibernation_snaphot()
+ *      @platform_mode - if set, use the platform driver, if available, to
+ *                       prepare the platform firmware for the transition.
+ *
+ *      Must be called with pm_mutex held
+ */
+
+int hibernation_restore(int platform_mode)
+{
+        int error;
+
+        pm_prepare_console();
+        suspend_console();
+        error = dpm_suspend_start(PMSG_QUIESCE);
+        if (!error) {
+                error = resume_target_kernel(platform_mode);
+                dpm_resume_end(PMSG_RECOVER);
+        }
+        resume_console();
+        pm_restore_console();
+        return error;
+}
+
+/**
+ *      hibernation_platform_enter - enter the hibernation state using the
+ *      platform driver (if available)
+ */
+
+int hibernation_platform_enter(void)
+{
+        int error;
+
+        if (!hibernation_ops)
+                return -ENOSYS;
+
+        /*
+         * We have cancelled the power transition by running
+         * hibernation_ops->finish() before saving the image, so we should let
+         * the firmware know that we're going to enter the sleep state after all
+         */
+        error = hibernation_ops->begin();
+        if (error)
+                goto Close;
+
+        entering_platform_hibernation = true;
+        suspend_console();
+        error = dpm_suspend_start(PMSG_HIBERNATE);
+        if (error) {
+                if (hibernation_ops->recover)
+                        hibernation_ops->recover();
+                goto Resume_devices;
+        }
+
+        error = dpm_suspend_noirq(PMSG_HIBERNATE);
+        if (error)
+                goto Resume_devices;
+
+        error = hibernation_ops->prepare();
+        if (error)
+                goto Platofrm_finish;
+
+        error = disable_nonboot_cpus();
+        if (error)
+                goto Platofrm_finish;
+
+        local_irq_disable();
+        sysdev_suspend(PMSG_HIBERNATE);
+        hibernation_ops->enter();
+        /* We should never get here */
+        while (1);
+
+        /*
+         * We don't need to reenable the nonboot CPUs or resume consoles, since
+         * the system is going to be halted anyway.
+         */
+ Platofrm_finish:
+        hibernation_ops->finish();
+
+        dpm_suspend_noirq(PMSG_RESTORE);
+
+ Resume_devices:
+        entering_platform_hibernation = false;
+        dpm_resume_end(PMSG_RESTORE);
+        resume_console();
+
+ Close:
+        hibernation_ops->end();
+
+        return error;
+}
+
+/**
+ *      power_down - Shut the machine down for hibernation.
+ *
+ *      Use the platform driver, if configured so; otherwise try
+ *      to power off or reboot.
+ */
+
+static void power_down(void)
+{
+        switch (hibernation_mode) {
+        case HIBERNATION_TEST:
+        case HIBERNATION_TESTPROC:
+                break;
+        case HIBERNATION_REBOOT:
+                kernel_restart(NULL);
+                break;
+        case HIBERNATION_PLATFORM:
+                hibernation_platform_enter();
+        case HIBERNATION_SHUTDOWN:
+                kernel_power_off();
+                break;
+        }
+        kernel_halt();
+        /*
+         * Valid image is on the disk, if we continue we risk serious data
+         * corruption after resume.
+         */
+        printk(KERN_CRIT "PM: Please power down manually\n");
+        while(1);
+}
+
+static int prepare_processes(void)
+{
+        int error = 0;
+
+        if (freeze_processes()) {
+                error = -EBUSY;
+                thaw_processes();
+        }
+        return error;
+}
+
+/**
+ *      hibernate - The granpappy of the built-in hibernation management
+ */
+
+int hibernate(void)
+{
+        int error;
+
+        mutex_lock(&pm_mutex);
+        /* The snapshot device should not be opened while we're running */
+        if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
+                error = -EBUSY;
+                goto Unlock;
+        }
+
+        pm_prepare_console();
+        error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
+        if (error)
+                goto Exit;
+
+        error = usermodehelper_disable();
+        if (error)
+                goto Exit;
+
+        /* Allocate memory management structures */
+        error = create_basic_memory_bitmaps();
+        if (error)
+                goto Exit;
+
+        printk(KERN_INFO "PM: Syncing filesystems ... ");
+        sys_sync();
+        printk("done.\n");
+
+        error = prepare_processes();
+        if (error)
+                goto Finish;
+
+        if (hibernation_test(TEST_FREEZER))
+                goto Thaw;
+
+        if (hibernation_testmode(HIBERNATION_TESTPROC))
+                goto Thaw;
+
+        error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
+        if (in_suspend && !error) {
+                unsigned int flags = 0;
+
+                if (hibernation_mode == HIBERNATION_PLATFORM)
+                        flags |= SF_PLATFORM_MODE;
+                pr_debug("PM: writing image.\n");
+                error = swsusp_write(flags);
+                swsusp_free();
+                if (!error)
+                        power_down();
+        } else {
+                pr_debug("PM: Image restored successfully.\n");
+                swsusp_free();
+        }
+ Thaw:
+        thaw_processes();
+ Finish:
+        free_basic_memory_bitmaps();
+        usermodehelper_enable();
+ Exit:
+        pm_notifier_call_chain(PM_POST_HIBERNATION);
+        pm_restore_console();
+        atomic_inc(&snapshot_device_available);
+ Unlock:
+        mutex_unlock(&pm_mutex);
+        return error;
+}
+
+
+/**
+ *      software_resume - Resume from a saved image.
+ *
+ *      Called as a late_initcall (so all devices are discovered and
+ *      initialized), we call swsusp to see if we have a saved image or not.
+ *      If so, we quiesce devices, the restore the saved image. We will
+ *      return above (in hibernate() ) if everything goes well.
+ *      Otherwise, we fail gracefully and return to the normally
+ *      scheduled program.
+ *
+ */
+
+static int software_resume(void)
+{
+        int error;
+        unsigned int flags;
+
+        /*
+         * If the user said "noresume".. bail out early.
+         */
+        if (noresume)
+                return 0;
+
+        /*
+         * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
+         * is configured into the kernel. Since the regular hibernate
+         * trigger path is via sysfs which takes a buffer mutex before
+         * calling hibernate functions (which take pm_mutex) this can
+         * cause lockdep to complain about a possible ABBA deadlock
+         * which cannot happen since we're in the boot code here and
+         * sysfs can't be invoked yet. Therefore, we use a subclass
+         * here to avoid lockdep complaining.
+         */
+        mutex_lock_nested(&pm_mutex, SINGLE_DEPTH_NESTING);
+
+        if (swsusp_resume_device)
+                goto Check_image;
+
+        if (!strlen(resume_file)) {
+                error = -ENOENT;
+                goto Unlock;
+        }
+
+        pr_debug("PM: Checking image partition %s\n", resume_file);
+
+        /* Check if the device is there */
+        swsusp_resume_device = name_to_dev_t(resume_file);
+        if (!swsusp_resume_device) {
+                /*
+                 * Some device discovery might still be in progress; we need
+                 * to wait for this to finish.
+                 */
+                wait_for_device_probe();
+                /*
+                 * We can't depend on SCSI devices being available after loading
+                 * one of their modules until scsi_complete_async_scans() is
+                 * called and the resume device usually is a SCSI one.
+                 */
+                scsi_complete_async_scans();
+
+                swsusp_resume_device = name_to_dev_t(resume_file);
+                if (!swsusp_resume_device) {
+                        error = -ENODEV;
+                        goto Unlock;
+                }
+        }
+
+ Check_image:
+        pr_debug("PM: Resume from partition %d:%d\n",
+                MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
+
+        pr_debug("PM: Checking hibernation image.\n");
+        error = swsusp_check();
+        if (error)
+                goto Unlock;
+
+        /* The snapshot device should not be opened while we're running */
+        if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
+                error = -EBUSY;
+                goto Unlock;
+        }
+
+        pm_prepare_console();
+        error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
+        if (error)
+                goto Finish;
+
+        error = usermodehelper_disable();
+        if (error)
+                goto Finish;
+
+        error = create_basic_memory_bitmaps();
+        if (error)
+                goto Finish;
+
+        pr_debug("PM: Preparing processes for restore.\n");
+        error = prepare_processes();
+        if (error) {
+                swsusp_close(FMODE_READ);
+                goto Done;
+        }
+
+        pr_debug("PM: Reading hibernation image.\n");
+
+        error = swsusp_read(&flags);
+        if (!error)
+                hibernation_restore(flags & SF_PLATFORM_MODE);
+
+        printk(KERN_ERR "PM: Restore failed, recovering.\n");
+        swsusp_free();
+        thaw_processes();
+ Done:
+        free_basic_memory_bitmaps();
+        usermodehelper_enable();
+ Finish:
+        pm_notifier_call_chain(PM_POST_RESTORE);
+        pm_restore_console();
+        atomic_inc(&snapshot_device_available);
+        /* For success case, the suspend path will release the lock */
+ Unlock:
+        mutex_unlock(&pm_mutex);
+        pr_debug("PM: Resume from disk failed.\n");
+        return error;
+}
+
+late_initcall(software_resume);
+
+
+static const char * const hibernation_modes[] = {
+        [HIBERNATION_PLATFORM]  = "platform",
+        [HIBERNATION_SHUTDOWN]  = "shutdown",
+        [HIBERNATION_REBOOT]    = "reboot",
+        [HIBERNATION_TEST]      = "test",
+        [HIBERNATION_TESTPROC]  = "testproc",
+};
+
+/**
+ *      disk - Control hibernation mode
+ *
+ *      Suspend-to-disk can be handled in several ways. We have a few options
+ *      for putting the system to sleep - using the platform driver (e.g. ACPI
+ *      or other hibernation_ops), powering off the system or rebooting the
+ *      system (for testing) as well as the two test modes.
+ *
+ *      The system can support 'platform', and that is known a priori (and
+ *      encoded by the presence of hibernation_ops). However, the user may
+ *      choose 'shutdown' or 'reboot' as alternatives, as well as one fo the
+ *      test modes, 'test' or 'testproc'.
+ *
+ *      show() will display what the mode is currently set to.
+ *      store() will accept one of
+ *
+ *      'platform'
+ *      'shutdown'
+ *      'reboot'
+ *      'test'
+ *      'testproc'
+ *
+ *      It will only change to 'platform' if the system
+ *      supports it (as determined by having hibernation_ops).
+ */
+
+static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
+                         char *buf)
+{
+        int i;
+        char *start = buf;
+
+        for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
+                if (!hibernation_modes[i])
+                        continue;
+                switch (i) {
+                case HIBERNATION_SHUTDOWN:
+                case HIBERNATION_REBOOT:
+                case HIBERNATION_TEST:
+                case HIBERNATION_TESTPROC:
+                        break;
+                case HIBERNATION_PLATFORM:
+                        if (hibernation_ops)
+                                break;
+                        /* not a valid mode, continue with loop */
+                        continue;
+                }
+                if (i == hibernation_mode)
+                        buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
+                else
+                        buf += sprintf(buf, "%s ", hibernation_modes[i]);
+        }
+        buf += sprintf(buf, "\n");
+        return buf-start;
+}
+
+
+static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
+                          const char *buf, size_t n)
+{
+        int error = 0;
+        int i;
+        int len;
+        char *p;
+        int mode = HIBERNATION_INVALID;
+
+        p = memchr(buf, '\n', n);
+        len = p ? p - buf : n;
+
+        mutex_lock(&pm_mutex);
+        for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
+                if (len == strlen(hibernation_modes[i])
+                    && !strncmp(buf, hibernation_modes[i], len)) {
+                        mode = i;
+                        break;
+                }
+        }
+        if (mode != HIBERNATION_INVALID) {
+                switch (mode) {
+                case HIBERNATION_SHUTDOWN:
+                case HIBERNATION_REBOOT:
+                case HIBERNATION_TEST:
+                case HIBERNATION_TESTPROC:
+                        hibernation_mode = mode;
+                        break;
+                case HIBERNATION_PLATFORM:
+                        if (hibernation_ops)
+                                hibernation_mode = mode;
+                        else
+                                error = -EINVAL;
+                }
+        } else
+                error = -EINVAL;
+
+        if (!error)
+                pr_debug("PM: Hibernation mode set to '%s'\n",
+                         hibernation_modes[mode]);
+        mutex_unlock(&pm_mutex);
+        return error ? error : n;
+}
+
+power_attr(disk);
+
+static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
+                           char *buf)
+{
+        return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
+                       MINOR(swsusp_resume_device));
+}
+
+static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
+                            const char *buf, size_t n)
+{
+        unsigned int maj, min;
+        dev_t res;
+        int ret = -EINVAL;
+
+        if (sscanf(buf, "%u:%u", &maj, &min) != 2)
+                goto out;
+
+        res = MKDEV(maj,min);
+        if (maj != MAJOR(res) || min != MINOR(res))
+                goto out;
+
+        mutex_lock(&pm_mutex);
+        swsusp_resume_device = res;
+        mutex_unlock(&pm_mutex);
+        printk(KERN_INFO "PM: Starting manual resume from disk\n");
+        noresume = 0;
+        software_resume();
+        ret = n;
+ out:
+        return ret;
+}
+
+power_attr(resume);
+
+static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
+                               char *buf)
+{
+        return sprintf(buf, "%lu\n", image_size);
+}
+
+static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
+                                const char *buf, size_t n)
+{
+        unsigned long size;
+
+        if (sscanf(buf, "%lu", &size) == 1) {
+                image_size = size;
+                return n;
+        }
+
+        return -EINVAL;
+}
+
+power_attr(image_size);
+
+static struct attribute * g[] = {
+        &disk_attr.attr,
+        &resume_attr.attr,
+        &image_size_attr.attr,
+        NULL,
+};
+
+
+static struct attribute_group attr_group = {
+        .attrs = g,
+};
+
+
+static int __init pm_disk_init(void)
+{
+        return sysfs_create_group(power_kobj, &attr_group);
+}
+
+core_initcall(pm_disk_init);
+
+
+static int __init resume_setup(char *str)
+{
+        if (noresume)
+                return 1;
+
+        strncpy( resume_file, str, 255 );
+        return 1;
+}
+
+static int __init resume_offset_setup(char *str)
+{
+        unsigned long long offset;
+
+        if (noresume)
+                return 1;
+
+        if (sscanf(str, "%llu", &offset) == 1)
+                swsusp_resume_block = offset;
+
+        return 1;
+}
+
+static int __init noresume_setup(char *str)
+{
+        noresume = 1;
+        return 1;
+}
+
+__setup("noresume", noresume_setup);
+__setup("resume_offset=", resume_offset_setup);
+__setup("resume=", resume_setup);