339 lines
6.8 KiB
C
339 lines
6.8 KiB
C
/*
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* linux/kernel/power/user.c
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*
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* This file provides the user space interface for software suspend/resume.
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*
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* Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
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*
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* This file is released under the GPLv2.
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*
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*/
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#include <linux/suspend.h>
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#include <linux/syscalls.h>
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#include <linux/string.h>
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#include <linux/device.h>
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#include <linux/miscdevice.h>
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#include <linux/mm.h>
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#include <linux/swap.h>
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#include <linux/swapops.h>
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#include <linux/pm.h>
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#include <linux/fs.h>
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#include <linux/cpu.h>
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#include <asm/uaccess.h>
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#include "power.h"
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#define SNAPSHOT_MINOR 231
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static struct snapshot_data {
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struct snapshot_handle handle;
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int swap;
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struct bitmap_page *bitmap;
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int mode;
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char frozen;
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char ready;
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} snapshot_state;
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static atomic_t device_available = ATOMIC_INIT(1);
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static int snapshot_open(struct inode *inode, struct file *filp)
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{
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struct snapshot_data *data;
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if (!atomic_add_unless(&device_available, -1, 0))
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return -EBUSY;
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if ((filp->f_flags & O_ACCMODE) == O_RDWR)
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return -ENOSYS;
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nonseekable_open(inode, filp);
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data = &snapshot_state;
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filp->private_data = data;
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memset(&data->handle, 0, sizeof(struct snapshot_handle));
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if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
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data->swap = swsusp_resume_device ? swap_type_of(swsusp_resume_device) : -1;
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data->mode = O_RDONLY;
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} else {
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data->swap = -1;
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data->mode = O_WRONLY;
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}
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data->bitmap = NULL;
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data->frozen = 0;
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data->ready = 0;
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return 0;
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}
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static int snapshot_release(struct inode *inode, struct file *filp)
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{
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struct snapshot_data *data;
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swsusp_free();
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data = filp->private_data;
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free_all_swap_pages(data->swap, data->bitmap);
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free_bitmap(data->bitmap);
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if (data->frozen) {
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down(&pm_sem);
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thaw_processes();
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enable_nonboot_cpus();
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up(&pm_sem);
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}
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atomic_inc(&device_available);
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return 0;
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}
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static ssize_t snapshot_read(struct file *filp, char __user *buf,
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size_t count, loff_t *offp)
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{
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struct snapshot_data *data;
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ssize_t res;
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data = filp->private_data;
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res = snapshot_read_next(&data->handle, count);
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if (res > 0) {
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if (copy_to_user(buf, data_of(data->handle), res))
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res = -EFAULT;
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else
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*offp = data->handle.offset;
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}
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return res;
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}
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static ssize_t snapshot_write(struct file *filp, const char __user *buf,
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size_t count, loff_t *offp)
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{
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struct snapshot_data *data;
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ssize_t res;
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data = filp->private_data;
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res = snapshot_write_next(&data->handle, count);
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if (res > 0) {
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if (copy_from_user(data_of(data->handle), buf, res))
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res = -EFAULT;
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else
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*offp = data->handle.offset;
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}
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return res;
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}
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static int snapshot_ioctl(struct inode *inode, struct file *filp,
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unsigned int cmd, unsigned long arg)
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{
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int error = 0;
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struct snapshot_data *data;
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loff_t offset, avail;
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if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
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return -ENOTTY;
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if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
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return -ENOTTY;
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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data = filp->private_data;
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switch (cmd) {
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case SNAPSHOT_FREEZE:
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if (data->frozen)
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break;
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down(&pm_sem);
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error = disable_nonboot_cpus();
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if (!error) {
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error = freeze_processes();
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if (error) {
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thaw_processes();
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error = -EBUSY;
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}
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}
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enable_nonboot_cpus();
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up(&pm_sem);
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if (!error)
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data->frozen = 1;
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break;
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case SNAPSHOT_UNFREEZE:
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if (!data->frozen)
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break;
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down(&pm_sem);
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thaw_processes();
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enable_nonboot_cpus();
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up(&pm_sem);
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data->frozen = 0;
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break;
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case SNAPSHOT_ATOMIC_SNAPSHOT:
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if (data->mode != O_RDONLY || !data->frozen || data->ready) {
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error = -EPERM;
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break;
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}
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down(&pm_sem);
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/* Free memory before shutting down devices. */
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error = swsusp_shrink_memory();
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if (!error) {
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error = device_suspend(PMSG_FREEZE);
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if (!error) {
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in_suspend = 1;
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error = swsusp_suspend();
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device_resume();
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}
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}
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up(&pm_sem);
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if (!error)
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error = put_user(in_suspend, (unsigned int __user *)arg);
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if (!error)
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data->ready = 1;
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break;
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case SNAPSHOT_ATOMIC_RESTORE:
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if (data->mode != O_WRONLY || !data->frozen ||
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!snapshot_image_loaded(&data->handle)) {
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error = -EPERM;
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break;
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}
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snapshot_free_unused_memory(&data->handle);
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down(&pm_sem);
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pm_prepare_console();
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error = device_suspend(PMSG_FREEZE);
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if (!error) {
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error = swsusp_resume();
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device_resume();
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}
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pm_restore_console();
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up(&pm_sem);
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break;
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case SNAPSHOT_FREE:
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swsusp_free();
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memset(&data->handle, 0, sizeof(struct snapshot_handle));
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data->ready = 0;
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break;
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case SNAPSHOT_SET_IMAGE_SIZE:
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image_size = arg;
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break;
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case SNAPSHOT_AVAIL_SWAP:
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avail = count_swap_pages(data->swap, 1);
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avail <<= PAGE_SHIFT;
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error = put_user(avail, (loff_t __user *)arg);
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break;
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case SNAPSHOT_GET_SWAP_PAGE:
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if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
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error = -ENODEV;
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break;
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}
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if (!data->bitmap) {
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data->bitmap = alloc_bitmap(count_swap_pages(data->swap, 0));
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if (!data->bitmap) {
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error = -ENOMEM;
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break;
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}
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}
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offset = alloc_swap_page(data->swap, data->bitmap);
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if (offset) {
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offset <<= PAGE_SHIFT;
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error = put_user(offset, (loff_t __user *)arg);
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} else {
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error = -ENOSPC;
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}
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break;
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case SNAPSHOT_FREE_SWAP_PAGES:
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if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
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error = -ENODEV;
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break;
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}
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free_all_swap_pages(data->swap, data->bitmap);
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free_bitmap(data->bitmap);
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data->bitmap = NULL;
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break;
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case SNAPSHOT_SET_SWAP_FILE:
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if (!data->bitmap) {
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/*
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* User space encodes device types as two-byte values,
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* so we need to recode them
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*/
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if (old_decode_dev(arg)) {
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data->swap = swap_type_of(old_decode_dev(arg));
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if (data->swap < 0)
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error = -ENODEV;
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} else {
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data->swap = -1;
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error = -EINVAL;
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}
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} else {
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error = -EPERM;
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}
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break;
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case SNAPSHOT_S2RAM:
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if (!data->frozen) {
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error = -EPERM;
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break;
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}
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if (down_trylock(&pm_sem)) {
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error = -EBUSY;
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break;
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}
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if (pm_ops->prepare) {
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error = pm_ops->prepare(PM_SUSPEND_MEM);
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if (error)
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goto OutS3;
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}
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/* Put devices to sleep */
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error = device_suspend(PMSG_SUSPEND);
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if (error) {
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printk(KERN_ERR "Failed to suspend some devices.\n");
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} else {
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/* Enter S3, system is already frozen */
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suspend_enter(PM_SUSPEND_MEM);
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/* Wake up devices */
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device_resume();
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}
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if (pm_ops->finish)
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pm_ops->finish(PM_SUSPEND_MEM);
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OutS3:
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up(&pm_sem);
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break;
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default:
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error = -ENOTTY;
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}
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return error;
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}
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static struct file_operations snapshot_fops = {
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.open = snapshot_open,
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.release = snapshot_release,
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.read = snapshot_read,
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.write = snapshot_write,
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.llseek = no_llseek,
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.ioctl = snapshot_ioctl,
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};
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static struct miscdevice snapshot_device = {
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.minor = SNAPSHOT_MINOR,
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.name = "snapshot",
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.fops = &snapshot_fops,
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};
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static int __init snapshot_device_init(void)
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{
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return misc_register(&snapshot_device);
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};
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device_initcall(snapshot_device_init);
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