path: root/kernel/power/hibernate.c

// 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/genhd.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;

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();
}

/**
 * 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)
{
	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;
	}
	lock_system_sleep();
	hibernation_ops = ops;
	if (ops)
		hibernation_mode = HIBERNATION_PLATFORM;
	else if (hibernation_mode