Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1367 insertions, 0 deletions

diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
new file mode 100644
index 000000000..30d1274f0
--- /dev/null
+++ b/kernel/power/hibernate.c
@@ -0,0 +1,1367 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 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@ucw.cz>
+ * Copyright (c) 2009 Rafael J. Wysocki, Novell Inc.
+ * Copyright (C) 2012 Bojan Smojver <bojan@rexursive.com>
+ */
+
+#define pr_fmt(fmt) "PM: hibernation: " fmt
+
+#include <linux/export.h>
+#include <linux/suspend.h>
+#include <linux/reboot.h>
+#include <linux/string.h>
+#include <linux/device.h>
+#include <linux/async.h>
+#include <linux/delay.h>
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/pm.h>
+#include <linux/nmi.h>
+#include <linux/console.h>
+#include <linux/cpu.h>
+#include <linux/freezer.h>
+#include <linux/gfp.h>
+#include <linux/syscore_ops.h>
+#include <linux/ctype.h>
+#include <linux/ktime.h>
+#include <linux/security.h>
+#include <linux/secretmem.h>
+#include <trace/events/power.h>
+
+#include "power.h"
+
+
+static int nocompress;
+static int noresume;
+static int nohibernate;
+static int resume_wait;
+static unsigned int resume_delay;
+static char resume_file[256] = CONFIG_PM_STD_PARTITION;
+dev_t swsusp_resume_device;
+sector_t swsusp_resume_block;
+__visible int in_suspend __nosavedata;
+
+enum {
+	HIBERNATION_INVALID,
+	HIBERNATION_PLATFORM,
+	HIBERNATION_SHUTDOWN,
+	HIBERNATION_REBOOT,
+#ifdef CONFIG_SUSPEND
+	HIBERNATION_SUSPEND,
+#endif
+	HIBERNATION_TEST_RESUME,
+	/* keep last */
+	__HIBERNATION_AFTER_LAST
+};
+#define HIBERNATION_MAX (__HIBERNATION_AFTER_LAST-1)
+#define HIBERNATION_FIRST (HIBERNATION_INVALID + 1)
+
+static int hibernation_mode = HIBERNATION_SHUTDOWN;
+
+bool freezer_test_done;
+bool snapshot_test;
+
+static const struct platform_hibernation_ops *hibernation_ops;
+
+static atomic_t hibernate_atomic = ATOMIC_INIT(1);
+
+bool hibernate_acquire(void)
+{
+	return atomic_add_unless(&hibernate_atomic, -1, 0);
+}
+
+void hibernate_release(void)
+{
+	atomic_inc(&hibernate_atomic);
+}
+
+bool hibernation_available(void)
+{
+	return nohibernate == 0 &&
+		!security_locked_down(LOCKDOWN_HIBERNATION) &&
+		!secretmem_active() && !cxl_mem_active();
+}
+
+/**
+ * hibernation_set_ops - Set the global hibernate operations.
+ * @ops: Hibernation operations to use in subsequent hibernation transitions.
+ */
+void hibernation_set_ops(const struct platform_hibernation_ops *ops)
+{
+	unsigned int sleep_flags;
+
+	if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
+	    && ops->prepare && ops->finish && ops->enter && ops->pre_restore
+	    && ops->restore_cleanup && ops->leave)) {
+		WARN_ON(1);
+		return;
+	}
+
+	sleep_flags = lock_system_sleep();
+
+	hibernation_ops = ops;
+	if (ops)
+		hibernation_mode = HIBERNATION_PLATFORM;
+	else if (hibernation_mode == HIBERNATION_PLATFORM)
+		hibernation_mode = HIBERNATION_SHUTDOWN;
+
+	unlock_system_sleep(sleep_flags);
+}
+EXPORT_SYMBOL_GPL(hibernation_set_ops);
+
+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)
+{
+	pr_info("debug: Waiting for 5 seconds.\n");
+	mdelay(5000);
+}
+
+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_test(int level) { return 0; }
+#endif /* !CONFIG_PM_DEBUG */
+
+/**
+ * platform_begin - Call platform to start hibernation.
+ * @platform_mode: Whether or not to use the platform driver.
+ */
+static int platform_begin(int platform_mode)
+{
+	return (platform_mode && hibernation_ops) ?
+		hibernation_ops->begin(PMSG_FREEZE) : 0;
+}
+
+/**
+ * platform_end - Call platform to finish transition to the working state.
+ * @platform_mode: Whether or not to use the platform driver.
+ */
+static void platform_end(int platform_mode)
+{
+	if (platform_mode && hibernation_ops)
+		hibernation_ops->end();
+}
+
+/**
+ * platform_pre_snapshot - Call platform to prepare the machine for hibernation.
+ * @platform_mode: Whether or not to use the platform driver.
+ *
+ * Use the platform driver to prepare the system for creating a hibernate image,
+ * if so configured, and return an error code if that fails.
+ */
+
+static int platform_pre_snapshot(int platform_mode)
+{
+	return (platform_mode && hibernation_ops) ?
+		hibernation_ops->pre_snapshot() : 0;
+}
+
+/**
+ * platform_leave - Call platform to prepare a transition to the working state.
+ * @platform_mode: Whether or not to use the platform driver.
+ *
+ * Use the platform driver prepare to prepare the machine for switching to the
+ * normal mode of operation.
+ *
+ * This routine is called on one CPU with interrupts disabled.
+ */
+static void platform_leave(int platform_mode)
+{
+	if (platform_mode && hibernation_ops)
+		hibernation_ops->leave();
+}
+
+/**
+ * platform_finish - Call platform to switch the system to the working state.
+ * @platform_mode: Whether or not to use the platform driver.
+ *
+ * Use the platform driver to switch the machine to the normal mode of
+ * operation.
+ *
+ * This routine 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 for hibernate image restoration.
+ * @platform_mode: Whether or not to use the platform driver.
+ *
+ * Use the platform driver to prepare the system for resume 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 to the working state after failing restore.
+ * @platform_mode: Whether or not to use the platform driver.
+ *
+ * Use the platform driver to switch the system 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 from a failure to suspend devices.
+ * @platform_mode: Whether or not to use the platform driver.
+ */
+static void platform_recover(int platform_mode)
+{
+	if (platform_mode && hibernation_ops && hibernation_ops->recover)
+		hibernation_ops->recover();
+}
+
+/**
+ * swsusp_show_speed - Print time elapsed between two events during hibernation.
+ * @start: Starting event.
+ * @stop: Final event.
+ * @nr_pages: Number of memory pages processed between @start and @stop.
+ * @msg: Additional diagnostic message to print.
+ */
+void swsusp_show_speed(ktime_t start, ktime_t stop,
+		      unsigned nr_pages, char *msg)
+{
+	ktime_t diff;
+	u64 elapsed_centisecs64;
+	unsigned int centisecs;
+	unsigned int k;
+	unsigned int kps;
+
+	diff = ktime_sub(stop, start);
+	elapsed_centisecs64 = ktime_divns(diff, 10*NSEC_PER_MSEC);
+	centisecs = elapsed_centisecs64;
+	if (centisecs == 0)
+		centisecs = 1;	/* avoid div-by-zero */
+	k = nr_pages * (PAGE_SIZE / 1024);
+	kps = (k * 100) / centisecs;
+	pr_info("%s %u kbytes in %u.%02u seconds (%u.%02u MB/s)\n",
+		msg, k, centisecs / 100, centisecs % 100, kps / 1000,
+		(kps % 1000) / 10);
+}
+
+__weak int arch_resume_nosmt(void)
+{
+	return 0;
+}
+
+/**
+ * create_image - Create a hibernation image.
+ * @platform_mode: Whether or not to use the platform driver.
+ *
+ * Execute device drivers' "late" and "noirq" freeze callbacks, create a
+ * hibernation image and run the drivers' "noirq" and "early" thaw callbacks.
+ *
+ * Control reappears in this routine after the subsequent restore.
+ */
+static int create_image(int platform_mode)
+{
+	int error;
+
+	error = dpm_suspend_end(PMSG_FREEZE);
+	if (error) {
+		pr_err("Some devices failed to power down, aborting\n");
+		return error;
+	}
+
+	error = platform_pre_snapshot(platform_mode);
+	if (error || hibernation_test(TEST_PLATFORM))
+		goto Platform_finish;
+
+	error = pm_sleep_disable_secondary_cpus();
+	if (error || hibernation_test(TEST_CPUS))
+		goto Enable_cpus;
+
+	local_irq_disable();
+
+	system_state = SYSTEM_SUSPEND;
+
+	error = syscore_suspend();
+	if (error) {
+		pr_err("Some system devices failed to power down, aborting\n");
+		goto Enable_irqs;
+	}
+
+	if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
+		goto Power_up;
+
+	in_suspend = 1;
+	save_processor_state();
+	trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);
+	error = swsusp_arch_suspend();
+	/* Restore control flow magically appears here */
+	restore_processor_state();
+	trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
+	if (error)
+		pr_err("Error %d creating image\n", error);
+
+	if (!in_suspend) {
+		events_check_enabled = false;
+		clear_or_poison_free_pages();
+	}
+
+	platform_leave(platform_mode);
+
+ Power_up:
+	syscore_resume();
+
+ Enable_irqs:
+	system_state = SYSTEM_RUNNING;
+	local_irq_enable();
+
+ Enable_cpus:
+	pm_sleep_enable_secondary_cpus();
+
+	/* Allow architectures to do nosmt-specific post-resume dances */
+	if (!in_suspend)
+		error = arch_resume_nosmt();
+
+ Platform_finish:
+	platform_finish(platform_mode);
+
+	dpm_resume_start(in_suspend ?
+		(error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
+
+	return error;
+}
+
+/**
+ * hibernation_snapshot - Quiesce devices and create a hibernation image.
+ * @platform_mode: If set, use platform driver to prepare for the transition.
+ *
+ * This routine must be called with system_transition_mutex held.
+ */
+int hibernation_snapshot(int platform_mode)
+{
+	pm_message_t msg;
+	int error;
+
+	pm_suspend_clear_flags();
+	error = platform_begin(platform_mode);
+	if (error)
+		goto Close;
+
+	/* Preallocate image memory before shutting down devices. */
+	error = hibernate_preallocate_memory();
+	if (error)
+		goto Close;
+
+	error = freeze_kernel_threads();
+	if (error)
+		goto Cleanup;
+
+	if (hibernation_test(TEST_FREEZER)) {
+
+		/*
+		 * Indicate to the caller that we are returning due to a
+		 * successful freezer test.
+		 */
+		freezer_test_done = true;
+		goto Thaw;
+	}
+
+	error = dpm_prepare(PMSG_FREEZE);
+	if (error) {
+		dpm_complete(PMSG_RECOVER);
+		goto Thaw;
+	}
+
+	suspend_console();
+	pm_restrict_gfp_mask();
+
+	error = dpm_suspend(PMSG_FREEZE);
+
+	if (error || hibernation_test(TEST_DEVICES))
+		platform_recover(platform_mode);
+	else
+		error = create_image(platform_mode);
+
+	/*
+	 * In the case that we call create_image() above, the control
+	 * returns here (1) after the image has been created or the
+	 * image creation has failed and (2) after a successful restore.
+	 */
+
+	/* We may need to release the preallocated image pages here. */
+	if (error || !in_suspend)
+		swsusp_free();
+
+	msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
+	dpm_resume(msg);
+
+	if (error || !in_suspend)
+		pm_restore_gfp_mask();
+
+	resume_console();
+	dpm_complete(msg);
+
+ Close:
+	platform_end(platform_mode);
+	return error;
+
+ Thaw:
+	thaw_kernel_threads();
+ Cleanup:
+	swsusp_free();
+	goto Close;
+}
+
+int __weak hibernate_resume_nonboot_cpu_disable(void)
+{
+	return suspend_disable_secondary_cpus();
+}
+
+/**
+ * resume_target_kernel - Restore system state from a hibernation image.
+ * @platform_mode: Whether or not to use the platform driver.
+ *
+ * Execute device drivers' "noirq" and "late" freeze callbacks, 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_end(PMSG_QUIESCE);
+	if (error) {
+		pr_err("Some devices failed to power down, aborting resume\n");
+		return error;
+	}
+
+	error = platform_pre_restore(platform_mode);
+	if (error)
+		goto Cleanup;
+
+	cpuidle_pause();
+
+	error = hibernate_resume_nonboot_cpu_disable();
+	if (error)
+		goto Enable_cpus;
+
+	local_irq_disable();
+	system_state = SYSTEM_SUSPEND;
+
+	error = syscore_suspend();
+	if (error)
+		goto Enable_irqs;
+
+	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 the place where
+		 * swsusp_arch_suspend() was called.
+		 */
+		BUG_ON(!error);
+		/*
+		 * This call to restore_highmem() reverts the changes made by
+		 * 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();
+
+	syscore_resume();
+
+ Enable_irqs:
+	system_state = SYSTEM_RUNNING;
+	local_irq_enable();
+
+ Enable_cpus:
+	pm_sleep_enable_secondary_cpus();
+
+ Cleanup:
+	platform_restore_cleanup(platform_mode);
+
+	dpm_resume_start(PMSG_RECOVER);
+
+	return error;
+}
+
+/**
+ * hibernation_restore - Quiesce devices and restore from a hibernation image.
+ * @platform_mode: If set, use platform driver to prepare for the transition.
+ *
+ * This routine must be called with system_transition_mutex held.  If it is
+ * successful, control reappears in the restored target kernel in
+ * hibernation_snapshot().
+ */
+int hibernation_restore(int platform_mode)
+{
+	int error;
+
+	pm_prepare_console();
+	suspend_console();
+	pm_restrict_gfp_mask();
+	error = dpm_suspend_start(PMSG_QUIESCE);
+	if (!error) {
+		error = resume_target_kernel(platform_mode);
+		/*
+		 * The above should either succeed and jump to the new kernel,
+		 * or return with an error. Otherwise things are just
+		 * undefined, so let's be paranoid.
+		 */
+		BUG_ON(!error);
+	}
+	dpm_resume_end(PMSG_RECOVER);
+	pm_restore_gfp_mask();
+	resume_console();
+	pm_restore_console();
+	return error;
+}
+
+/**
+ * hibernation_platform_enter - Power off the system using the platform driver.
+ */
+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(PMSG_HIBERNATE);
+	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_end(PMSG_HIBERNATE);
+	if (error)
+		goto Resume_devices;
+
+	error = hibernation_ops->prepare();
+	if (error)
+		goto Platform_finish;
+
+	error = pm_sleep_disable_secondary_cpus();
+	if (error)
+		goto Enable_cpus;
+
+	local_irq_disable();
+	system_state = SYSTEM_SUSPEND;
+	syscore_suspend();
+	if (pm_wakeup_pending()) {
+		error = -EAGAIN;
+		goto Power_up;
+	}
+
+	hibernation_ops->enter();
+	/* We should never get here */
+	while (1);
+
+ Power_up:
+	syscore_resume();
+	system_state = SYSTEM_RUNNING;
+	local_irq_enable();
+
+ Enable_cpus:
+	pm_sleep_enable_secondary_cpus();
+
+ Platform_finish:
+	hibernation_ops->finish();
+
+	dpm_resume_start(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, to put the system into the sleep
+ * state corresponding to hibernation, or try to power it off or reboot,
+ * depending on the value of hibernation_mode.
+ */
+static void power_down(void)
+{
+#ifdef CONFIG_SUSPEND
+	int error;
+
+	if (hibernation_mode == HIBERNATION_SUSPEND) {
+		error = suspend_devices_and_enter(mem_sleep_current);
+		if (error) {
+			hibernation_mode = hibernation_ops ?
+						HIBERNATION_PLATFORM :
+						HIBERNATION_SHUTDOWN;
+		} else {
+			/* Restore swap signature. */
+			error = swsusp_unmark();
+			if (error)
+				pr_err("Swap will be unusable! Try swapon -a.\n");
+
+			return;
+		}
+	}
+#endif
+
+	switch (hibernation_mode) {
+	case HIBERNATION_REBOOT:
+		kernel_restart(NULL);
+		break;
+	case HIBERNATION_PLATFORM:
+		hibernation_platform_enter();
+		fallthrough;
+	case HIBERNATION_SHUTDOWN:
+		if (kernel_can_power_off())
+			kernel_power_off();
+		break;
+	}
+	kernel_halt();
+	/*
+	 * Valid image is on the disk, if we continue we risk serious data
+	 * corruption after resume.
+	 */
+	pr_crit("Power down manually\n");
+	while (1)
+		cpu_relax();
+}
+
+static int load_image_and_restore(void)
+{
+	int error;
+	unsigned int flags;
+	fmode_t mode = FMODE_READ;
+
+	if (snapshot_test)
+		mode |= FMODE_EXCL;
+
+	pm_pr_dbg("Loading hibernation image.\n");
+
+	lock_device_hotplug();
+	error = create_basic_memory_bitmaps();
+	if (error) {
+		swsusp_close(mode);
+		goto Unlock;
+	}
+
+	error = swsusp_read(&flags);
+	swsusp_close(mode);
+	if (!error)
+		error = hibernation_restore(flags & SF_PLATFORM_MODE);
+
+	pr_err("Failed to load image, recovering.\n");
+	swsusp_free();
+	free_basic_memory_bitmaps();
+ Unlock:
+	unlock_device_hotplug();
+
+	return error;
+}
+
+/**
+ * hibernate - Carry out system hibernation, including saving the image.
+ */
+int hibernate(void)
+{
+	unsigned int sleep_flags;
+	int error;
+
+	if (!hibernation_available()) {
+		pm_pr_dbg("Hibernation not available.\n");
+		return -EPERM;
+	}
+
+	sleep_flags = lock_system_sleep();
+	/* The snapshot device should not be opened while we're running */
+	if (!hibernate_acquire()) {
+		error = -EBUSY;
+		goto Unlock;
+	}
+
+	pr_info("hibernation entry\n");
+	pm_prepare_console();
+	error = pm_notifier_call_chain_robust(PM_HIBERNATION_PREPARE, PM_POST_HIBERNATION);
+	if (error)
+		goto Restore;
+
+	ksys_sync_helper();
+
+	error = freeze_processes();
+	if (error)
+		goto Exit;
+
+	/* protected by system_transition_mutex */
+	snapshot_test = false;
+
+	lock_device_hotplug();
+	/* Allocate memory management structures */
+	error = create_basic_memory_bitmaps();
+	if (error)
+		goto Thaw;
+
+	error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
+	if (error || freezer_test_done)
+		goto Free_bitmaps;
+
+	if (in_suspend) {
+		unsigned int flags = 0;
+
+		if (hibernation_mode == HIBERNATION_PLATFORM)
+			flags |= SF_PLATFORM_MODE;
+		if (nocompress)
+			flags |= SF_NOCOMPRESS_MODE;
+		else
+		        flags |= SF_CRC32_MODE;
+
+		pm_pr_dbg("Writing hibernation image.\n");
+		error = swsusp_write(flags);
+		swsusp_free();
+		if (!error) {
+			if (hibernation_mode == HIBERNATION_TEST_RESUME)
+				snapshot_test = true;
+			else
+				power_down();
+		}
+		in_suspend = 0;
+		pm_restore_gfp_mask();
+	} else {
+		pm_pr_dbg("Hibernation image restored successfully.\n");
+	}
+
+ Free_bitmaps:
+	free_basic_memory_bitmaps();
+ Thaw:
+	unlock_device_hotplug();
+	if (snapshot_test) {
+		pm_pr_dbg("Checking hibernation image\n");
+		error = swsusp_check();
+		if (!error)
+			error = load_image_and_restore();
+	}
+	thaw_processes();
+
+	/* Don't bother checking whether freezer_test_done is true */
+	freezer_test_done = false;
+ Exit:
+	pm_notifier_call_chain(PM_POST_HIBERNATION);
+ Restore:
+	pm_restore_console();
+	hibernate_release();
+ Unlock:
+	unlock_system_sleep(sleep_flags);
+	pr_info("hibernation exit\n");
+
+	return error;
+}
+
+/**
+ * hibernate_quiet_exec - Execute a function with all devices frozen.
+ * @func: Function to execute.
+ * @data: Data pointer to pass to @func.
+ *
+ * Return the @func return value or an error code if it cannot be executed.
+ */
+int hibernate_quiet_exec(int (*func)(void *data), void *data)
+{
+	unsigned int sleep_flags;
+	int error;
+
+	sleep_flags = lock_system_sleep();
+
+	if (!hibernate_acquire()) {
+		error = -EBUSY;
+		goto unlock;
+	}
+
+	pm_prepare_console();
+
+	error = pm_notifier_call_chain_robust(PM_HIBERNATION_PREPARE, PM_POST_HIBERNATION);
+	if (error)
+		goto restore;
+
+	error = freeze_processes();
+	if (error)
+		goto exit;
+
+	lock_device_hotplug();
+
+	pm_suspend_clear_flags();
+
+	error = platform_begin(true);
+	if (error)
+		goto thaw;
+
+	error = freeze_kernel_threads();
+	if (error)
+		goto thaw;
+
+	error = dpm_prepare(PMSG_FREEZE);
+	if (error)
+		goto dpm_complete;
+
+	suspend_console();
+
+	error = dpm_suspend(PMSG_FREEZE);
+	if (error)
+		goto dpm_resume;
+
+	error = dpm_suspend_end(PMSG_FREEZE);
+	if (error)
+		goto dpm_resume;
+
+	error = platform_pre_snapshot(true);
+	if (error)
+		goto skip;
+
+	error = func(data);
+
+skip:
+	platform_finish(true);
+
+	dpm_resume_start(PMSG_THAW);
+
+dpm_resume:
+	dpm_resume(PMSG_THAW);
+
+	resume_console();
+
+dpm_complete:
+	dpm_complete(PMSG_THAW);
+
+	thaw_kernel_threads();
+
+thaw:
+	platform_end(true);
+
+	unlock_device_hotplug();
+
+	thaw_processes();
+
+exit:
+	pm_notifier_call_chain(PM_POST_HIBERNATION);
+
+restore:
+	pm_restore_console();
+
+	hibernate_release();
+
+unlock:
+	unlock_system_sleep(sleep_flags);
+
+	return error;
+}
+EXPORT_SYMBOL_GPL(hibernate_quiet_exec);
+
+/**
+ * software_resume - Resume from a saved hibernation image.
+ *
+ * This routine is called as a late initcall, when all devices have been
+ * discovered and initialized already.
+ *
+ * The image reading code is called to see if there is a hibernation image
+ * available for reading.  If that is the case, devices are quiesced and the
+ * contents of memory is restored from the saved image.
+ *
+ * If this is successful, control reappears in the restored target kernel in
+ * hibernation_snapshot() which returns to hibernate().  Otherwise, the routine
+ * attempts to recover gracefully and make the kernel return to the normal mode
+ * of operation.
+ */
+static int software_resume(void)
+{
+	int error;
+
+	/*
+	 * If the user said "noresume".. bail out early.
+	 */
+	if (noresume || !hibernation_available())
+		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 system_transition_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(&system_transition_mutex, SINGLE_DEPTH_NESTING);
+
+	snapshot_test = false;
+
+	if (swsusp_resume_device)
+		goto Check_image;
+
+	if (!strlen(resume_file)) {
+		error = -ENOENT;
+		goto Unlock;
+	}
+
+	pm_pr_dbg("Checking hibernation image partition %s\n", resume_file);
+
+	if (resume_delay) {
+		pr_info("Waiting %dsec before reading resume device ...\n",
+			resume_delay);
+		ssleep(resume_delay);
+	}
+
+	/* 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();
+
+		if (resume_wait) {
+			while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
+				msleep(10);
+			async_synchronize_full();
+		}
+
+		swsusp_resume_device = name_to_dev_t(resume_file);
+		if (!swsusp_resume_device) {
+			error = -ENODEV;
+			goto Unlock;
+		}
+	}
+
+ Check_image:
+	pm_pr_dbg("Hibernation image partition %d:%d present\n",
+		MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
+
+	pm_pr_dbg("Looking for hibernation image.\n");
+	error = swsusp_check();
+	if (error)
+		goto Unlock;
+
+	/* The snapshot device should not be opened while we're running */
+	if (!hibernate_acquire()) {
+		error = -EBUSY;
+		swsusp_close(FMODE_READ | FMODE_EXCL);
+		goto Unlock;
+	}
+
+	pr_info("resume from hibernation\n");
+	pm_prepare_console();
+	error = pm_notifier_call_chain_robust(PM_RESTORE_PREPARE, PM_POST_RESTORE);
+	if (error)
+		goto Restore;
+
+	pm_pr_dbg("Preparing processes for hibernation restore.\n");
+	error = freeze_processes();
+	if (error)
+		goto Close_Finish;
+
+	error = freeze_kernel_threads();
+	if (error) {
+		thaw_processes();
+		goto Close_Finish;
+	}
+
+	error = load_image_and_restore();
+	thaw_processes();
+ Finish:
+	pm_notifier_call_chain(PM_POST_RESTORE);
+ Restore:
+	pm_restore_console();
+	pr_info("resume failed (%d)\n", error);
+	hibernate_release();
+	/* For success case, the suspend path will release the lock */
+ Unlock:
+	mutex_unlock(&system_transition_mutex);
+	pm_pr_dbg("Hibernation image not present or could not be loaded.\n");
+	return error;
+ Close_Finish:
+	swsusp_close(FMODE_READ | FMODE_EXCL);
+	goto Finish;
+}
+
+late_initcall_sync(software_resume);
+
+
+static const char * const hibernation_modes[] = {
+	[HIBERNATION_PLATFORM]	= "platform",
+	[HIBERNATION_SHUTDOWN]	= "shutdown",
+	[HIBERNATION_REBOOT]	= "reboot",
+#ifdef CONFIG_SUSPEND
+	[HIBERNATION_SUSPEND]	= "suspend",
+#endif
+	[HIBERNATION_TEST_RESUME]	= "test_resume",
+};
+
+/*
+ * /sys/power/disk - Control hibernation mode.
+ *
+ * Hibernation can be handled in several ways.  There are a few different ways
+ * to put the system into the sleep state: using the platform driver (e.g. ACPI
+ * or other hibernation_ops), powering it off or rebooting it (for testing
+ * mostly).
+ *
+ * The sysfs file /sys/power/disk provides an interface for selecting the
+ * hibernation mode to use.  Reading from this file causes the available modes
+ * to be printed.  There are 3 modes that can be supported:
+ *
+ *	'platform'
+ *	'shutdown'
+ *	'reboot'
+ *
+ * If a platform hibernation driver is in use, 'platform' will be supported
+ * and will be used by default.  Otherwise, 'shutdown' will be used by default.
+ * The selected option (i.e. the one corresponding to the current value of
+ * hibernation_mode) is enclosed by a square bracket.
+ *
+ * To select a given hibernation mode it is necessary to write the mode's
+ * string representation (as returned by reading from /sys/power/disk) back
+ * into /sys/power/disk.
+ */
+
+static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
+			 char *buf)
+{
+	int i;
+	char *start = buf;
+
+	if (!hibernation_available())
+		return sprintf(buf, "[disabled]\n");
+
+	for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
+		if (!hibernation_modes[i])
+			continue;
+		switch (i) {
+		case HIBERNATION_SHUTDOWN:
+		case HIBERNATION_REBOOT:
+#ifdef CONFIG_SUSPEND
+		case HIBERNATION_SUSPEND:
+#endif
+		case HIBERNATION_TEST_RESUME:
+			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 mode = HIBERNATION_INVALID;
+	unsigned int sleep_flags;
+	int error = 0;
+	int len;
+	char *p;
+	int i;
+
+	if (!hibernation_available())
+		return -EPERM;
+
+	p = memchr(buf, '\n', n);
+	len = p ? p - buf : n;
+
+	sleep_flags = lock_system_sleep();
+	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:
+#ifdef CONFIG_SUSPEND
+		case HIBERNATION_SUSPEND:
+#endif
+		case HIBERNATION_TEST_RESUME:
+			hibernation_mode = mode;
+			break;
+		case HIBERNATION_PLATFORM:
+			if (hibernation_ops)
+				hibernation_mode = mode;
+			else
+				error = -EINVAL;
+		}
+	} else
+		error = -EINVAL;
+
+	if (!error)
+		pm_pr_dbg("Hibernation mode set to '%s'\n",
+			       hibernation_modes[mode]);
+	unlock_system_sleep(sleep_flags);
+	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 sleep_flags;
+	int len = n;
+	char *name;
+	dev_t res;
+
+	if (len && buf[len-1] == '\n')
+		len--;
+	name = kstrndup(buf, len, GFP_KERNEL);
+	if (!name)
+		return -ENOMEM;
+
+	res = name_to_dev_t(name);
+	kfree(name);
+	if (!res)
+		return -EINVAL;
+
+	sleep_flags = lock_system_sleep();
+	swsusp_resume_device = res;
+	unlock_system_sleep(sleep_flags);
+
+	pm_pr_dbg("Configured hibernation resume from disk to %u\n",
+		  swsusp_resume_device);
+	noresume = 0;
+	software_resume();
+	return n;
+}
+
+power_attr(resume);
+
+static ssize_t resume_offset_show(struct kobject *kobj,
+				  struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%llu\n", (unsigned long long)swsusp_resume_block);
+}
+
+static ssize_t resume_offset_store(struct kobject *kobj,
+				   struct kobj_attribute *attr, const char *buf,
+				   size_t n)
+{
+	unsigned long long offset;
+	int rc;
+
+	rc = kstrtoull(buf, 0, &offset);
+	if (rc)
+		return rc;
+	swsusp_resume_block = offset;
+
+	return n;
+}
+
+power_attr(resume_offset);
+
+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 ssize_t reserved_size_show(struct kobject *kobj,
+				  struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%lu\n", reserved_size);
+}
+
+static ssize_t reserved_size_store(struct kobject *kobj,
+				   struct kobj_attribute *attr,
+				   const char *buf, size_t n)
+{
+	unsigned long size;
+
+	if (sscanf(buf, "%lu", &size) == 1) {
+		reserved_size = size;
+		return n;
+	}
+
+	return -EINVAL;
+}
+
+power_attr(reserved_size);
+
+static struct attribute *g[] = {
+	&disk_attr.attr,
+	&resume_offset_attr.attr,
+	&resume_attr.attr,
+	&image_size_attr.attr,
+	&reserved_size_attr.attr,
+	NULL,
+};
+
+
+static const 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 hibernate_setup(char *str)
+{
+	if (!strncmp(str, "noresume", 8)) {
+		noresume = 1;
+	} else if (!strncmp(str, "nocompress", 10)) {
+		nocompress = 1;
+	} else if (!strncmp(str, "no", 2)) {
+		noresume = 1;
+		nohibernate = 1;
+	} else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)
+		   && !strncmp(str, "protect_image", 13)) {
+		enable_restore_image_protection();
+	}
+	return 1;
+}
+
+static int __init noresume_setup(char *str)
+{
+	noresume = 1;
+	return 1;
+}
+
+static int __init resumewait_setup(char *str)
+{
+	resume_wait = 1;
+	return 1;
+}
+
+static int __init resumedelay_setup(char *str)
+{
+	int rc = kstrtouint(str, 0, &resume_delay);
+
+	if (rc)
+		pr_warn("resumedelay: bad option string '%s'\n", str);
+	return 1;
+}
+
+static int __init nohibernate_setup(char *str)
+{
+	noresume = 1;
+	nohibernate = 1;
+	return 1;
+}
+
+__setup("noresume", noresume_setup);
+__setup("resume_offset=", resume_offset_setup);
+__setup("resume=", resume_setup);
+__setup("hibernate=", hibernate_setup);
+__setup("resumewait", resumewait_setup);
+__setup("resumedelay=", resumedelay_setup);
+__setup("nohibernate", nohibernate_setup);