/*
* linux/kernel/power/user.c
*
* This file provides the user space interface for software suspend/resume.
*
* Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
*
* This file is released under the GPLv2.
*
*/
#include <linux/suspend.h>
#include <linux/syscalls.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 <asm/uaccess.h>
#include "power.h"
#define SNAPSHOT_MINOR 231
static struct snapshot_data {
struct snapshot_handle handle;
int swap;
struct bitmap_page *bitmap;
int mode;
char frozen;
char ready;
} snapshot_state;
static atomic_t device_available = ATOMIC_INIT(1);
static int snapshot_open(struct inode *inode, struct file *filp)
{
struct snapshot_data *data;
if (!atomic_add_unless(&device_available, -1, 0))
return -EBUSY;
if ((filp->f_flags & O_ACCMODE) == O_RDWR)
return -ENOSYS;
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) {
data->swap = swsusp_resume_device ? swap_type_of(swsusp_resume_device) : -1;
data->mode = O_RDONLY;
} else {
data->swap = -1;
data->mode = O_WRONLY;
}
data->bitmap = NULL;
data->frozen = 0;
data->ready = 0;
return 0;
}
static int snapshot_release(struct inode *inode, struct file *filp)
{
struct snapshot_data *data;
swsusp_free();
data = filp->private_data;
free_all_swap_pages(data->swap, data->bitmap);
free_bitmap(data->bitmap);
if (data->frozen) {
down(&pm_sem);
thaw_processes();
enable_nonboot_cpus();
up(&pm_sem);
}
atomic_inc(&device_available);
return 0;
}
static ssize_t snapshot_read(struct file *filp, char __user *buf,
size_t count, loff_t *offp)
{
struct snapshot_data *data;
ssize_t res;
data = filp->private_data;
res = snapshot_read_next(&data->handle, count);
if (res > 0) {
if (copy_to_user(buf, data_of(data->handle), res))
res = -EFAULT;
else
*offp = data->handle.offset;
}
return res;
}
static ssize_t snapshot_write(struct file *filp, const char __user *buf,
size_t count, loff_t *offp)
{
struct snapshot_data *data;
ssize_t res;
data = filp->private_data;
res = snapshot_write_next(&data->handle, count);
if (res > 0) {
if (copy_from_user(data_of(data->handle), buf, res))
res = -EFAULT;
else
*offp = data->handle.offset;
}
return res;
}
static int snapshot_ioctl(struct inode *inode, struct file *filp,
unsigned int cmd, unsigned long arg)
{
int error = 0;
struct snapshot_data *data;
loff_t offset, avail;
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;
data = filp->private_data;
switch (cmd) {
case SNAPSHOT_FREEZE:
if (data->frozen)
break;
down(&pm_sem);
disable_nonboot_cpus();
if (freeze_processes()) {
thaw_processes();
enable_nonboot_cpus();
error = -EBUSY;
}
up(&pm_sem);
if (!error)
data->frozen = 1;
break;
case SNAPSHOT_UNFREEZE:
if (!data->frozen)
break;
down(&pm_sem);
thaw_processes();
enable_nonboot_cpus();
up(&pm_sem);
data->frozen = 0;
break;
case SNAPSHOT_ATOMIC_SNAPSHOT:
if (data->mode != O_RDONLY || !data->frozen || data->ready) {
error = -EPERM;
break;
}
down(&pm_sem);
/* Free memory before shutting down devices. */
error = swsusp_shrink_memory();
if (!error) {
error = device_suspend(PMSG_FREEZE);
if (!error) {
in_suspend = 1;
error = swsusp_suspend();
device_resume();
}
}
up(&pm_sem);
if (!error)
error = put_user(in_suspend, (unsigned int __user *)arg);
if (!error)
data->ready = 1;
break;
case SNAPSHOT_ATOMIC_RESTORE:
if (data->mode != O_WRONLY || !data->frozen ||
!snapshot_image_loaded(&data->handle)) {
error = -EPERM;
break;
}
down(&pm_sem);
pm_prepare_console();
error = device_suspend(PMSG_FREEZE);
if (!error) {
error = swsusp_resume();
device_resume();
}
pm_restore_console();
up(&pm_sem);
break;
case SNAPSHOT_FREE:
swsusp_free();
memset(&data->handle, 0, sizeof(struct snapshot_handle));
data->ready = 0;
break;
case SNAPSHOT_SET_IMAGE_SIZE:
image_size = arg;
break;
case SNAPSHOT_AVAIL_SWAP:
avail = count_swap_pages(data->swap, 1);
avail <<= PAGE_SHIFT;
error = put_user(avail, (loff_t __user *)arg);
break;
case SNAPSHOT_GET_SWAP_PAGE:
if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
error = -ENODEV;
break;
}
if (!data->bitmap) {
data->bitmap = alloc_bitmap(count_swap_pages(data->swap, 0));
if (!data->bitmap) {
error = -ENOMEM;
break;
}
}
offset = alloc_swap_page(data->swap, data->bitmap);
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, data->bitmap);
free_bitmap(data->bitmap);
data->bitmap = NULL;
break;
case SNAPSHOT_SET_SWAP_FILE:
if (!data->bitmap) {
/*
* User space encodes device types as two-byte values,
* so we need to recode them
*/
if (old_decode_dev(arg)) {
data->swap = swap_type_of(old_decode_dev(arg));
if (data->swap < 0)
error = -ENODEV;
} else {
data->swap = -1;
error = -EINVAL;
}
} else {
error = -EPERM;
}
break;
default:
error = -ENOTTY;
}
return error;
}
static struct file_operations snapshot_fops = {
.open = snapshot_open,
.release = snapshot_release,
.read = snapshot_read,
.write = snapshot_write,
.llseek = no_llseek,
.ioctl = snapshot_ioctl,
};
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);
