463 lines
9.5 KiB
C
463 lines
9.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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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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#include <linux/suspend.h>
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#include <linux/reboot.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/compat.h>
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#include <linux/console.h>
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#include <linux/cpu.h>
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#include <linux/freezer.h>
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#include <linux/uaccess.h>
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#include "power.h"
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static bool need_wait;
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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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int mode;
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bool frozen;
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bool ready;
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bool platform_support;
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bool free_bitmaps;
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dev_t dev;
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} snapshot_state;
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int is_hibernate_resume_dev(dev_t dev)
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{
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return hibernation_available() && snapshot_state.dev == dev;
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}
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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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int error;
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if (!hibernation_available())
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return -EPERM;
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lock_system_sleep();
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if (!hibernate_acquire()) {
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error = -EBUSY;
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goto Unlock;
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}
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if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
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hibernate_release();
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error = -ENOSYS;
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goto Unlock;
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}
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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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/* Hibernating. The image device should be accessible. */
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data->swap = swap_type_of(swsusp_resume_device, 0);
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data->mode = O_RDONLY;
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data->free_bitmaps = false;
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error = pm_notifier_call_chain_robust(PM_HIBERNATION_PREPARE, PM_POST_HIBERNATION);
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} else {
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/*
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* Resuming. We may need to wait for the image device to
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* appear.
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*/
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need_wait = true;
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data->swap = -1;
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data->mode = O_WRONLY;
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error = pm_notifier_call_chain_robust(PM_RESTORE_PREPARE, PM_POST_RESTORE);
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if (!error) {
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error = create_basic_memory_bitmaps();
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data->free_bitmaps = !error;
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}
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}
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if (error)
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hibernate_release();
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data->frozen = false;
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data->ready = false;
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data->platform_support = false;
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data->dev = 0;
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Unlock:
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unlock_system_sleep();
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return error;
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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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lock_system_sleep();
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swsusp_free();
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data = filp->private_data;
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data->dev = 0;
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free_all_swap_pages(data->swap);
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if (data->frozen) {
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pm_restore_gfp_mask();
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free_basic_memory_bitmaps();
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thaw_processes();
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} else if (data->free_bitmaps) {
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free_basic_memory_bitmaps();
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}
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pm_notifier_call_chain(data->mode == O_RDONLY ?
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PM_POST_HIBERNATION : PM_POST_RESTORE);
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hibernate_release();
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unlock_system_sleep();
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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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loff_t pg_offp = *offp & ~PAGE_MASK;
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lock_system_sleep();
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data = filp->private_data;
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if (!data->ready) {
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res = -ENODATA;
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goto Unlock;
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}
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if (!pg_offp) { /* on page boundary? */
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res = snapshot_read_next(&data->handle);
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if (res <= 0)
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goto Unlock;
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} else {
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res = PAGE_SIZE - pg_offp;
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}
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res = simple_read_from_buffer(buf, count, &pg_offp,
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data_of(data->handle), res);
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if (res > 0)
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*offp += res;
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Unlock:
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unlock_system_sleep();
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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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loff_t pg_offp = *offp & ~PAGE_MASK;
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if (need_wait) {
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wait_for_device_probe();
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need_wait = false;
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}
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lock_system_sleep();
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data = filp->private_data;
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if (!pg_offp) {
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res = snapshot_write_next(&data->handle);
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if (res <= 0)
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goto unlock;
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} else {
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res = PAGE_SIZE - pg_offp;
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}
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if (!data_of(data->handle)) {
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res = -EINVAL;
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goto unlock;
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}
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res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
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buf, count);
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if (res > 0)
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*offp += res;
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unlock:
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unlock_system_sleep();
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return res;
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}
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struct compat_resume_swap_area {
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compat_loff_t offset;
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u32 dev;
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} __packed;
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static int snapshot_set_swap_area(struct snapshot_data *data,
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void __user *argp)
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{
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sector_t offset;
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dev_t swdev;
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if (swsusp_swap_in_use())
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return -EPERM;
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if (in_compat_syscall()) {
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struct compat_resume_swap_area swap_area;
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if (copy_from_user(&swap_area, argp, sizeof(swap_area)))
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return -EFAULT;
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swdev = new_decode_dev(swap_area.dev);
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offset = swap_area.offset;
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} else {
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struct resume_swap_area swap_area;
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if (copy_from_user(&swap_area, argp, sizeof(swap_area)))
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return -EFAULT;
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swdev = new_decode_dev(swap_area.dev);
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offset = swap_area.offset;
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}
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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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data->swap = swap_type_of(swdev, offset);
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if (data->swap < 0)
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return swdev ? -ENODEV : -EINVAL;
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data->dev = swdev;
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return 0;
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}
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static long snapshot_ioctl(struct file *filp, unsigned int cmd,
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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 size;
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sector_t offset;
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if (need_wait) {
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wait_for_device_probe();
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need_wait = false;
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}
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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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if (!mutex_trylock(&system_transition_mutex))
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return -EBUSY;
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lock_device_hotplug();
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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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ksys_sync_helper();
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error = freeze_processes();
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if (error)
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break;
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error = create_basic_memory_bitmaps();
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if (error)
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thaw_processes();
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else
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data->frozen = true;
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break;
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case SNAPSHOT_UNFREEZE:
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if (!data->frozen || data->ready)
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break;
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pm_restore_gfp_mask();
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free_basic_memory_bitmaps();
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data->free_bitmaps = false;
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thaw_processes();
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data->frozen = false;
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break;
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case SNAPSHOT_CREATE_IMAGE:
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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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pm_restore_gfp_mask();
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error = hibernation_snapshot(data->platform_support);
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if (!error) {
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error = put_user(in_suspend, (int __user *)arg);
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data->ready = !freezer_test_done && !error;
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freezer_test_done = false;
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}
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break;
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case SNAPSHOT_ATOMIC_RESTORE:
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snapshot_write_finalize(&data->handle);
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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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error = hibernation_restore(data->platform_support);
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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 = false;
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/*
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* It is necessary to thaw kernel threads here, because
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* SNAPSHOT_CREATE_IMAGE may be invoked directly after
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* SNAPSHOT_FREE. In that case, if kernel threads were not
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* thawed, the preallocation of memory carried out by
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* hibernation_snapshot() might run into problems (i.e. it
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* might fail or even deadlock).
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*/
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thaw_kernel_threads();
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break;
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case SNAPSHOT_PREF_IMAGE_SIZE:
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image_size = arg;
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break;
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case SNAPSHOT_GET_IMAGE_SIZE:
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if (!data->ready) {
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error = -ENODATA;
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break;
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}
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size = snapshot_get_image_size();
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size <<= PAGE_SHIFT;
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error = put_user(size, (loff_t __user *)arg);
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break;
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case SNAPSHOT_AVAIL_SWAP_SIZE:
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size = count_swap_pages(data->swap, 1);
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size <<= PAGE_SHIFT;
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error = put_user(size, (loff_t __user *)arg);
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break;
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case SNAPSHOT_ALLOC_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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offset = alloc_swapdev_block(data->swap);
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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);
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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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/*
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* Tasks are frozen and the notifiers have been called with
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* PM_HIBERNATION_PREPARE
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*/
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error = suspend_devices_and_enter(PM_SUSPEND_MEM);
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data->ready = false;
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break;
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case SNAPSHOT_PLATFORM_SUPPORT:
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data->platform_support = !!arg;
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break;
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case SNAPSHOT_POWER_OFF:
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if (data->platform_support)
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error = hibernation_platform_enter();
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break;
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case SNAPSHOT_SET_SWAP_AREA:
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error = snapshot_set_swap_area(data, (void __user *)arg);
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break;
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default:
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error = -ENOTTY;
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}
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unlock_device_hotplug();
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mutex_unlock(&system_transition_mutex);
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return error;
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}
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#ifdef CONFIG_COMPAT
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static long
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snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
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BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t));
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switch (cmd) {
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case SNAPSHOT_GET_IMAGE_SIZE:
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case SNAPSHOT_AVAIL_SWAP_SIZE:
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case SNAPSHOT_ALLOC_SWAP_PAGE:
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case SNAPSHOT_CREATE_IMAGE:
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case SNAPSHOT_SET_SWAP_AREA:
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return snapshot_ioctl(file, cmd,
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(unsigned long) compat_ptr(arg));
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default:
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return snapshot_ioctl(file, cmd, arg);
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}
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}
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#endif /* CONFIG_COMPAT */
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static const 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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.unlocked_ioctl = snapshot_ioctl,
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#ifdef CONFIG_COMPAT
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.compat_ioctl = snapshot_compat_ioctl,
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#endif
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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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