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451 lines
9.4 KiB
451 lines
9.4 KiB
// 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 <[email protected]> |
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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 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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wait_for_device_probe(); |
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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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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; |
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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 (_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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