diff options
Diffstat (limited to 'kernel/power/user.c')
| -rw-r--r-- | kernel/power/user.c | 466 |
1 files changed, 466 insertions, 0 deletions
diff --git a/kernel/power/user.c b/kernel/power/user.c new file mode 100644 index 000000000..3a4e70366 --- /dev/null +++ b/kernel/power/user.c @@ -0,0 +1,466 @@ +// 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 <rjw@sisk.pl> + */ + +#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: + snapshot_write_finalize(&data->handle); + 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, + .llseek = no_llseek, + .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); |