SAFE public projects git trees. - safe/jmp/linux-2.6/blob - kernel/power/user.c

   1 /*
   2  * linux/kernel/power/user.c
   3  *
   4  * This file provides the user space interface for software suspend/resume.
   5  *
   6  * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
   7  *
   8  * This file is released under the GPLv2.
   9  *
  10  */
  11
  12 #include <linux/suspend.h>
  13 #include <linux/syscalls.h>
  14 #include <linux/string.h>
  15 #include <linux/device.h>
  16 #include <linux/miscdevice.h>
  17 #include <linux/mm.h>
  18 #include <linux/swap.h>
  19 #include <linux/swapops.h>
  20 #include <linux/pm.h>
  21 #include <linux/fs.h>
  22
  23 #include <asm/uaccess.h>
  24
  25 #include "power.h"
  26
  27 #define SNAPSHOT_MINOR  231
  28
  29 static struct snapshot_data {
  30         struct snapshot_handle handle;
  31         int swap;
  32         struct bitmap_page *bitmap;
  33         int mode;
  34         char frozen;
  35         char ready;
  36 } snapshot_state;
  37
  38 static atomic_t device_available = ATOMIC_INIT(1);
  39
  40 static int snapshot_open(struct inode *inode, struct file *filp)
  41 {
  42         struct snapshot_data *data;
  43
  44         if (!atomic_add_unless(&device_available, -1, 0))
  45                 return -EBUSY;
  46
  47         if ((filp->f_flags & O_ACCMODE) == O_RDWR)
  48                 return -ENOSYS;
  49
  50         nonseekable_open(inode, filp);
  51         data = &snapshot_state;
  52         filp->private_data = data;
  53         memset(&data->handle, 0, sizeof(struct snapshot_handle));
  54         if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
  55                 data->swap = swsusp_resume_device ? swap_type_of(swsusp_resume_device) : -1;
  56                 data->mode = O_RDONLY;
  57         } else {
  58                 data->swap = -1;
  59                 data->mode = O_WRONLY;
  60         }
  61         data->bitmap = NULL;
  62         data->frozen = 0;
  63         data->ready = 0;
  64
  65         return 0;
  66 }
  67
  68 static int snapshot_release(struct inode *inode, struct file *filp)
  69 {
  70         struct snapshot_data *data;
  71
  72         swsusp_free();
  73         data = filp->private_data;
  74         free_all_swap_pages(data->swap, data->bitmap);
  75         free_bitmap(data->bitmap);
  76         if (data->frozen) {
  77                 down(&pm_sem);
  78                 thaw_processes();
  79                 enable_nonboot_cpus();
  80                 up(&pm_sem);
  81         }
  82         atomic_inc(&device_available);
  83         return 0;
  84 }
  85
  86 static ssize_t snapshot_read(struct file *filp, char __user *buf,
  87                              size_t count, loff_t *offp)
  88 {
  89         struct snapshot_data *data;
  90         ssize_t res;
  91
  92         data = filp->private_data;
  93         res = snapshot_read_next(&data->handle, count);
  94         if (res > 0) {
  95                 if (copy_to_user(buf, data_of(data->handle), res))
  96                         res = -EFAULT;
  97                 else
  98                         *offp = data->handle.offset;
  99         }
 100         return res;
 101 }
 102
 103 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
 104                               size_t count, loff_t *offp)
 105 {
 106         struct snapshot_data *data;
 107         ssize_t res;
 108
 109         data = filp->private_data;
 110         res = snapshot_write_next(&data->handle, count);
 111         if (res > 0) {
 112                 if (copy_from_user(data_of(data->handle), buf, res))
 113                         res = -EFAULT;
 114                 else
 115                         *offp = data->handle.offset;
 116         }
 117         return res;
 118 }
 119
 120 static int snapshot_ioctl(struct inode *inode, struct file *filp,
 121                           unsigned int cmd, unsigned long arg)
 122 {
 123         int error = 0;
 124         struct snapshot_data *data;
 125         loff_t offset, avail;
 126
 127         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
 128                 return -ENOTTY;
 129         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
 130                 return -ENOTTY;
 131         if (!capable(CAP_SYS_ADMIN))
 132                 return -EPERM;
 133
 134         data = filp->private_data;
 135
 136         switch (cmd) {
 137
 138         case SNAPSHOT_FREEZE:
 139                 if (data->frozen)
 140                         break;
 141                 sys_sync();
 142                 down(&pm_sem);
 143                 pm_prepare_console();
 144                 disable_nonboot_cpus();
 145                 if (freeze_processes()) {
 146                         thaw_processes();
 147                         enable_nonboot_cpus();
 148                         pm_restore_console();
 149                         error = -EBUSY;
 150                 }
 151                 up(&pm_sem);
 152                 if (!error)
 153                         data->frozen = 1;
 154                 break;
 155
 156         case SNAPSHOT_UNFREEZE:
 157                 if (!data->frozen)
 158                         break;
 159                 down(&pm_sem);
 160                 thaw_processes();
 161                 enable_nonboot_cpus();
 162                 pm_restore_console();
 163                 up(&pm_sem);
 164                 data->frozen = 0;
 165                 break;
 166
 167         case SNAPSHOT_ATOMIC_SNAPSHOT:
 168                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
 169                         error = -EPERM;
 170                         break;
 171                 }
 172                 down(&pm_sem);
 173                 /* Free memory before shutting down devices. */
 174                 error = swsusp_shrink_memory();
 175                 if (!error) {
 176                         error = device_suspend(PMSG_FREEZE);
 177                         if (!error) {
 178                                 in_suspend = 1;
 179                                 error = swsusp_suspend();
 180                                 device_resume();
 181                         }
 182                 }
 183                 up(&pm_sem);
 184                 if (!error)
 185                         error = put_user(in_suspend, (unsigned int __user *)arg);
 186                 if (!error)
 187                         data->ready = 1;
 188                 break;
 189
 190         case SNAPSHOT_ATOMIC_RESTORE:
 191                 if (data->mode != O_WRONLY || !data->frozen ||
 192                     !snapshot_image_loaded(&data->handle)) {
 193                         error = -EPERM;
 194                         break;
 195                 }
 196                 down(&pm_sem);
 197                 pm_prepare_console();
 198                 error = device_suspend(PMSG_FREEZE);
 199                 if (!error) {
 200                         error = swsusp_resume();
 201                         device_resume();
 202                 }
 203                 pm_restore_console();
 204                 up(&pm_sem);
 205                 break;
 206
 207         case SNAPSHOT_FREE:
 208                 swsusp_free();
 209                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
 210                 data->ready = 0;
 211                 break;
 212
 213         case SNAPSHOT_SET_IMAGE_SIZE:
 214                 image_size = arg;
 215                 break;
 216
 217         case SNAPSHOT_AVAIL_SWAP:
 218                 avail = count_swap_pages(data->swap, 1);
 219                 avail <<= PAGE_SHIFT;
 220                 error = put_user(avail, (loff_t __user *)arg);
 221                 break;
 222
 223         case SNAPSHOT_GET_SWAP_PAGE:
 224                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 225                         error = -ENODEV;
 226                         break;
 227                 }
 228                 if (!data->bitmap) {
 229                         data->bitmap = alloc_bitmap(count_swap_pages(data->swap, 0));
 230                         if (!data->bitmap) {
 231                                 error = -ENOMEM;
 232                                 break;
 233                         }
 234                 }
 235                 offset = alloc_swap_page(data->swap, data->bitmap);
 236                 if (offset) {
 237                         offset <<= PAGE_SHIFT;
 238                         error = put_user(offset, (loff_t __user *)arg);
 239                 } else {
 240                         error = -ENOSPC;
 241                 }
 242                 break;
 243
 244         case SNAPSHOT_FREE_SWAP_PAGES:
 245                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 246                         error = -ENODEV;
 247                         break;
 248                 }
 249                 free_all_swap_pages(data->swap, data->bitmap);
 250                 free_bitmap(data->bitmap);
 251                 data->bitmap = NULL;
 252                 break;
 253
 254         case SNAPSHOT_SET_SWAP_FILE:
 255                 if (!data->bitmap) {
 256                         /*
 257                          * User space encodes device types as two-byte values,
 258                          * so we need to recode them
 259                          */
 260                         if (old_decode_dev(arg)) {
 261                                 data->swap = swap_type_of(old_decode_dev(arg));
 262                                 if (data->swap < 0)
 263                                         error = -ENODEV;
 264                         } else {
 265                                 data->swap = -1;
 266                                 error = -EINVAL;
 267                         }
 268                 } else {
 269                         error = -EPERM;
 270                 }
 271                 break;
 272
 273         default:
 274                 error = -ENOTTY;
 275
 276         }
 277
 278         return error;
 279 }
 280
 281 static struct file_operations snapshot_fops = {
 282         .open = snapshot_open,
 283         .release = snapshot_release,
 284         .read = snapshot_read,
 285         .write = snapshot_write,
 286         .llseek = no_llseek,
 287         .ioctl = snapshot_ioctl,
 288 };
 289
 290 static struct miscdevice snapshot_device = {
 291         .minor = SNAPSHOT_MINOR,
 292         .name = "snapshot",
 293         .fops = &snapshot_fops,
 294 };
 295
 296 static int __init snapshot_device_init(void)
 297 {
 298         return misc_register(&snapshot_device);
 299 };
 300
 301 device_initcall(snapshot_device_init);