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Diffstat (limited to '')
| -rw-r--r-- | kernel/power/user.c | 301 |
1 files changed, 301 insertions, 0 deletions
diff --git a/kernel/power/user.c b/kernel/power/user.c new file mode 100644 index 000000000000..8cabc405ca10 --- /dev/null +++ b/kernel/power/user.c @@ -0,0 +1,301 @@ +/* + * 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; + sys_sync(); + down(&pm_sem); + pm_prepare_console(); + disable_nonboot_cpus(); + if (freeze_processes()) { + thaw_processes(); + enable_nonboot_cpus(); + pm_restore_console(); + 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(); + pm_restore_console(); + 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); 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