// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/kernel/power/user.c
*
* This file provides the user space interface for software suspend/resume.
*
* Copyright (C) 2006 Rafael J. Wysocki <[email protected]>
*/
#include <linux/suspend.h>
#include <linux/reboot.h>
#include <linux/string.h>
#include <linux/device.h>
#include <linux/miscdevice.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/pm.h>
#include <linux/fs.h>
#include <linux/compat.h>
#include <linux/console.h>
#include <linux/cpu.h>
#include <linux/freezer.h>
#include <linux/uaccess.h>
#include "power.h"
static bool need_wait;
static struct snapshot_data {
struct snapshot_handle handle;
int swap;
int mode;
bool frozen;
bool ready;
bool platform_support;
bool free_bitmaps;
dev_t dev;
} snapshot_state;
int is_hibernate_resume_dev(dev_t dev)
{
return hibernation_available() && snapshot_state.dev == dev;
}
static int snapshot_open(struct inode *inode, struct file *filp)
{
struct snapshot_data *data;
unsigned int sleep_flags;
int error;
if (!hibernation_available())
return -EPERM;
sleep_flags = lock_system_sleep();
if (!hibernate_acquire()) {
error = -EBUSY;
goto Unlock;
}
if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
hibernate_release();
error = -ENOSYS;
goto Unlock;
}
nonseekable_open(inode, filp);
data = &snapshot_state;
filp->private_data = data;
memset(&data->handle, 0, sizeof(struct snapshot_handle));
if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
/* Hibernating. The image device should be accessible. */
data->swap = swap_type_of(swsusp_resume_device, 0);
data->mode = O_RDONLY;
data->free_bitmaps = false;
error = pm_notifier_call_chain_robust(PM_HIBERNATION_PREPARE, PM_POST_HIBERNATION);
} else {
/*
* Resuming. We may need to wait for the image device to
* appear.
*/
need_wait = true;
data->swap = -1;
data->mode = O_WRONLY;
error = pm_notifier_call_chain_robust(PM_RESTORE_PREPARE, PM_POST_RESTORE);
if (!error) {
error = create_basic_memory_bitmaps();
data->free_bitmaps = !error;
}
}
if (error)
hibernate_release();
data->frozen = false;
data->ready = false;
data->platform_support = false;
data->dev = 0;
Unlock:
unlock_system_sleep(sleep_flags);
return error;
}
static int snapshot_release(struct inode *inode, struct file *filp)
{
struct snapshot_data *data;
unsigned int sleep_flags;
sleep_flags = lock_system_sleep();
swsusp_free();
data = filp->private_data;
data->dev = 0;
free_all_swap_pages(data->swap);
if (data->frozen) {
pm_restore_gfp_mask();
free_basic_memory_bitmaps();
thaw_processes();
} else if (data->free_bitmaps) {
free_basic_memory_bitmaps();
}
pm_notifier_call_chain(data->mode == O_RDONLY ?
PM_POST_HIBERNATION : PM_POST_RESTORE);
hibernate_release();
unlock_system_sleep(sleep_flags);
return 0;
}
static ssize_t snapshot_read(struct file *filp, char __user *buf,
size_t count, loff_t *offp)
{
loff_t pg_offp = *offp & ~PAGE_MASK;
struct snapshot_data *data;
unsigned int sleep_flags;
ssize_t res;
sleep_flags = lock_system_sleep();
data = filp->private_data;
if (!data->ready) {
res = -ENODATA;
goto Unlock;
}
if (!pg_offp) { /* on page boundary? */
res = snapshot_read_next(&data->handle);
if (res <= 0)
goto Unlock;
} else {
res = PAGE_SIZE - pg_offp;
}
res = simple_read_from_buffer(buf, count, &pg_offp,
data_of(data->handle), res);
if (res > 0)
*offp += res;
Unlock:
unlock_system_sleep(sleep_flags);
return res;
}
static ssize_t snapshot_write(struct file *filp, const char __user *buf,
size_t count, loff_t *offp)
{
loff_t pg_offp = *offp & ~PAGE_MASK;
struct snapshot_data *data;
unsigned long sleep_flags;
ssize_t res;
if (need_wait) {
wait_for_device_probe();
need_wait = false;
}
sleep_flags = lock_system_sleep();
data = filp->private_data;
if (!pg_offp) {
res = snapshot_write_next(&data->handle);
if (res <= 0)
goto unlock;
} else {
res = PAGE_SIZE;
}
if (!data_of(data->handle)) {
res = -EINVAL;
goto unlock;
}
res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
buf, count);
if (res > 0)
*offp += res;
unlock:
unlock_system_sleep(sleep_flags);
return res;
}
struct compat_resume_swap_area {
compat_loff_t offset;
u32 dev;
} __packed;
static int snapshot_set_swap_area(struct snapshot_data *data,
void __user *argp)
{
sector_t offset;
dev_t swdev;
if (swsusp_swap_in_use())
return -EPERM;
if (in_compat_syscall()) {
struct compat_resume_swap_area swap_area;
if (copy_from_user(&swap_area, argp, sizeof(swap_area)))
return -EFAULT;
swdev = new_decode_dev(swap_area.dev);
offset = swap_area.offset;
} else {
struct resume_swap_area swap_area;
if (copy_from_user(&swap_area, argp, sizeof(swap_area)))
return -EFAULT;
swdev = new_decode_dev(swap_area.dev);
offset = swap_area.offset;
}
/*
* User space encodes device types as two-byte values,
* so we need to recode them
*/
data->swap = swap_type_of(swdev, offset);
if (data->swap < 0)
return swdev ? -ENODEV : -EINVAL;
data->dev = swdev;
return 0;
}
static long snapshot_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg)
{
int error = 0;
struct snapshot_data *data;
loff_t size;
sector_t offset;
if (need_wait) {
wait_for_device_probe();
need_wait = false;
}
if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
return -ENOTTY;
if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
return -ENOTTY;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (!mutex_trylock(&system_transition_mutex))
return -EBUSY;
lock_device_hotplug();
data = filp->private_data;
switch (cmd) {
case SNAPSHOT_FREEZE:
if (data->frozen)
break;
ksys_sync_helper();
error = freeze_processes();
if (error)
break;
error = create_basic_memory_bitmaps();
if (error)
thaw_processes();
else
data->frozen = true;
break;
case SNAPSHOT_UNFREEZE:
if (!data->frozen || data->ready)
break;
pm_restore_gfp_mask();
free_basic_memory_bitmaps();
data->free_bitmaps = false;
thaw_processes();
data->frozen = false;
break;
case SNAPSHOT_CREATE_IMAGE:
if (data->mode != O_RDONLY || !data->frozen || data->ready) {
error = -EPERM;
break;
}
pm_restore_gfp_mask();
error = hibernation_snapshot(data->platform_support);
if (!error) {
error = put_user(in_suspend, (int __user *)arg);
data->ready = !freezer_test_done && !error;
freezer_test_done = false;
}
break;
case SNAPSHOT_ATOMIC_RESTORE:
error = snapshot_write_finalize(&data->handle);
if (error)
break;
if (data->mode != O_WRONLY || !data->frozen ||
!snapshot_image_loaded(&data->handle)) {
error = -EPERM;
break;
}
error = hibernation_restore(data->platform_support);
break;
case SNAPSHOT_FREE:
swsusp_free();
memset(&data->handle, 0, sizeof(struct snapshot_handle));
data->ready = false;
/*
* It is necessary to thaw kernel threads here, because
* SNAPSHOT_CREATE_IMAGE may be invoked directly after
* SNAPSHOT_FREE. In that case, if kernel threads were not
* thawed, the preallocation of memory carried out by
* hibernation_snapshot() might run into problems (i.e. it
* might fail or even deadlock).
*/
thaw_kernel_threads();
break;
case SNAPSHOT_PREF_IMAGE_SIZE:
image_size = arg;
break;
case SNAPSHOT_GET_IMAGE_SIZE:
if (!data->ready) {
error = -ENODATA;
break;
}
size = snapshot_get_image_size();
size <<= PAGE_SHIFT;
error = put_user(size, (loff_t __user *)arg);
break;
case SNAPSHOT_AVAIL_SWAP_SIZE:
size = count_swap_pages(data->swap, 1);
size <<= PAGE_SHIFT;
error = put_user(size, (loff_t __user *)arg);
break;
case SNAPSHOT_ALLOC_SWAP_PAGE:
if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
error = -ENODEV;
break;
}
offset = alloc_swapdev_block(data->swap);
if (offset) {
offset <<= PAGE_SHIFT;
error = put_user(offset, (loff_t __user *)arg);
} else {
error = -ENOSPC;
}
break;
case SNAPSHOT_FREE_SWAP_PAGES:
if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
error = -ENODEV;
break;
}
free_all_swap_pages(data->swap);
break;
case SNAPSHOT_S2RAM:
if (!data->frozen) {
error = -EPERM;
break;
}
/*
* Tasks are frozen and the notifiers have been called with
* PM_HIBERNATION_PREPARE
*/
error = suspend_devices_and_enter(PM_SUSPEND_MEM);
data->ready = false;
break;
case SNAPSHOT_PLATFORM_SUPPORT:
data->platform_support = !!arg;
break;
case SNAPSHOT_POWER_OFF:
if (data->platform_support)
error = hibernation_platform_enter();
break;
case SNAPSHOT_SET_SWAP_AREA:
error = snapshot_set_swap_area(data, (void __user *)arg);
break;
default:
error = -ENOTTY;
}
unlock_device_hotplug();
mutex_unlock(&system_transition_mutex);
return error;
}
#ifdef CONFIG_COMPAT
static long
snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t));
switch (cmd) {
case SNAPSHOT_GET_IMAGE_SIZE:
case SNAPSHOT_AVAIL_SWAP_SIZE:
case SNAPSHOT_ALLOC_SWAP_PAGE:
case SNAPSHOT_CREATE_IMAGE:
case SNAPSHOT_SET_SWAP_AREA:
return snapshot_ioctl(file, cmd,
(unsigned long) compat_ptr(arg));
default:
return snapshot_ioctl(file, cmd, arg);
}
}
#endif /* CONFIG_COMPAT */
static const struct file_operations snapshot_fops = {
.open = snapshot_open,
.release = snapshot_release,
.read = snapshot_read,
.write = snapshot_write,
.unlocked_ioctl = snapshot_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = snapshot_compat_ioctl,
#endif
};
static struct miscdevice snapshot_device = {
.minor = SNAPSHOT_MINOR,
.name = "snapshot",
.fops = &snapshot_fops,
};
static int __init snapshot_device_init(void)
{
return misc_register(&snapshot_device);
};
device_initcall(snapshot_device_init);
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