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/reboot.h>
  15 #include <linux/string.h>
  16 #include <linux/device.h>
  17 #include <linux/miscdevice.h>
  18 #include <linux/mm.h>
  19 #include <linux/swap.h>
  20 #include <linux/swapops.h>
  21 #include <linux/pm.h>
  22 #include <linux/fs.h>
  23 #include <linux/console.h>
  24 #include <linux/cpu.h>
  25 #include <linux/freezer.h>
  26
  27 #include <asm/uaccess.h>
  28
  29 #include "power.h"
  30
  31 #define SNAPSHOT_MINOR  231
  32
  33 static struct snapshot_data {
  34         struct snapshot_handle handle;
  35         int swap;
  36         int mode;
  37         char frozen;
  38         char ready;
  39         char platform_suspend;
  40 } snapshot_state;
  41
  42 atomic_t snapshot_device_available = ATOMIC_INIT(1);
  43
  44 static int snapshot_open(struct inode *inode, struct file *filp)
  45 {
  46         struct snapshot_data *data;
  47
  48         if (!atomic_add_unless(&snapshot_device_available, -1, 0))
  49                 return -EBUSY;
  50
  51         if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
  52                 atomic_inc(&snapshot_device_available);
  53                 return -ENOSYS;
  54         }
  55         if(create_basic_memory_bitmaps()) {
  56                 atomic_inc(&snapshot_device_available);
  57                 return -ENOMEM;
  58         }
  59         nonseekable_open(inode, filp);
  60         data = &snapshot_state;
  61         filp->private_data = data;
  62         memset(&data->handle, 0, sizeof(struct snapshot_handle));
  63         if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
  64                 data->swap = swsusp_resume_device ?
  65                         swap_type_of(swsusp_resume_device, 0, NULL) : -1;
  66                 data->mode = O_RDONLY;
  67         } else {
  68                 data->swap = -1;
  69                 data->mode = O_WRONLY;
  70         }
  71         data->frozen = 0;
  72         data->ready = 0;
  73         data->platform_suspend = 0;
  74
  75         return 0;
  76 }
  77
  78 static int snapshot_release(struct inode *inode, struct file *filp)
  79 {
  80         struct snapshot_data *data;
  81
  82         swsusp_free();
  83         free_basic_memory_bitmaps();
  84         data = filp->private_data;
  85         free_all_swap_pages(data->swap);
  86         if (data->frozen) {
  87                 mutex_lock(&pm_mutex);
  88                 thaw_processes();
  89                 mutex_unlock(&pm_mutex);
  90         }
  91         atomic_inc(&snapshot_device_available);
  92         return 0;
  93 }
  94
  95 static ssize_t snapshot_read(struct file *filp, char __user *buf,
  96                              size_t count, loff_t *offp)
  97 {
  98         struct snapshot_data *data;
  99         ssize_t res;
 100
 101         data = filp->private_data;
 102         if (!data->ready)
 103                 return -ENODATA;
 104         res = snapshot_read_next(&data->handle, count);
 105         if (res > 0) {
 106                 if (copy_to_user(buf, data_of(data->handle), res))
 107                         res = -EFAULT;
 108                 else
 109                         *offp = data->handle.offset;
 110         }
 111         return res;
 112 }
 113
 114 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
 115                               size_t count, loff_t *offp)
 116 {
 117         struct snapshot_data *data;
 118         ssize_t res;
 119
 120         data = filp->private_data;
 121         res = snapshot_write_next(&data->handle, count);
 122         if (res > 0) {
 123                 if (copy_from_user(data_of(data->handle), buf, res))
 124                         res = -EFAULT;
 125                 else
 126                         *offp = data->handle.offset;
 127         }
 128         return res;
 129 }
 130
 131 static int snapshot_ioctl(struct inode *inode, struct file *filp,
 132                           unsigned int cmd, unsigned long arg)
 133 {
 134         int error = 0;
 135         struct snapshot_data *data;
 136         loff_t avail;
 137         sector_t offset;
 138
 139         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
 140                 return -ENOTTY;
 141         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
 142                 return -ENOTTY;
 143         if (!capable(CAP_SYS_ADMIN))
 144                 return -EPERM;
 145
 146         data = filp->private_data;
 147
 148         switch (cmd) {
 149
 150         case SNAPSHOT_FREEZE:
 151                 if (data->frozen)
 152                         break;
 153                 mutex_lock(&pm_mutex);
 154                 error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
 155                 if (!error) {
 156                         error = freeze_processes();
 157                         if (error)
 158                                 thaw_processes();
 159                 }
 160                 if (error)
 161                         pm_notifier_call_chain(PM_POST_HIBERNATION);
 162                 mutex_unlock(&pm_mutex);
 163                 if (!error)
 164                         data->frozen = 1;
 165                 break;
 166
 167         case SNAPSHOT_UNFREEZE:
 168                 if (!data->frozen || data->ready)
 169                         break;
 170                 mutex_lock(&pm_mutex);
 171                 thaw_processes();
 172                 pm_notifier_call_chain(PM_POST_HIBERNATION);
 173                 mutex_unlock(&pm_mutex);
 174                 data->frozen = 0;
 175                 break;
 176
 177         case SNAPSHOT_ATOMIC_SNAPSHOT:
 178                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
 179                         error = -EPERM;
 180                         break;
 181                 }
 182                 error = hibernation_snapshot(data->platform_suspend);
 183                 if (!error)
 184                         error = put_user(in_suspend, (unsigned int __user *)arg);
 185                 if (!error)
 186                         data->ready = 1;
 187                 break;
 188
 189         case SNAPSHOT_ATOMIC_RESTORE:
 190                 snapshot_write_finalize(&data->handle);
 191                 if (data->mode != O_WRONLY || !data->frozen ||
 192                     !snapshot_image_loaded(&data->handle)) {
 193                         error = -EPERM;
 194                         break;
 195                 }
 196                 error = hibernation_restore(data->platform_suspend);
 197                 break;
 198
 199         case SNAPSHOT_FREE:
 200                 swsusp_free();
 201                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
 202                 data->ready = 0;
 203                 break;
 204
 205         case SNAPSHOT_SET_IMAGE_SIZE:
 206                 image_size = arg;
 207                 break;
 208
 209         case SNAPSHOT_AVAIL_SWAP:
 210                 avail = count_swap_pages(data->swap, 1);
 211                 avail <<= PAGE_SHIFT;
 212                 error = put_user(avail, (loff_t __user *)arg);
 213                 break;
 214
 215         case SNAPSHOT_GET_SWAP_PAGE:
 216                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 217                         error = -ENODEV;
 218                         break;
 219                 }
 220                 offset = alloc_swapdev_block(data->swap);
 221                 if (offset) {
 222                         offset <<= PAGE_SHIFT;
 223                         error = put_user(offset, (sector_t __user *)arg);
 224                 } else {
 225                         error = -ENOSPC;
 226                 }
 227                 break;
 228
 229         case SNAPSHOT_FREE_SWAP_PAGES:
 230                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 231                         error = -ENODEV;
 232                         break;
 233                 }
 234                 free_all_swap_pages(data->swap);
 235                 break;
 236
 237         case SNAPSHOT_SET_SWAP_FILE:
 238                 if (!swsusp_swap_in_use()) {
 239                         /*
 240                          * User space encodes device types as two-byte values,
 241                          * so we need to recode them
 242                          */
 243                         if (old_decode_dev(arg)) {
 244                                 data->swap = swap_type_of(old_decode_dev(arg),
 245                                                         0, NULL);
 246                                 if (data->swap < 0)
 247                                         error = -ENODEV;
 248                         } else {
 249                                 data->swap = -1;
 250                                 error = -EINVAL;
 251                         }
 252                 } else {
 253                         error = -EPERM;
 254                 }
 255                 break;
 256
 257         case SNAPSHOT_S2RAM:
 258                 if (!data->frozen) {
 259                         error = -EPERM;
 260                         break;
 261                 }
 262                 if (!mutex_trylock(&pm_mutex)) {
 263                         error = -EBUSY;
 264                         break;
 265                 }
 266                 /*
 267                  * Tasks are frozen and the notifiers have been called with
 268                  * PM_HIBERNATION_PREPARE
 269                  */
 270                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 271                 mutex_unlock(&pm_mutex);
 272                 break;
 273
 274         case SNAPSHOT_PMOPS:
 275                 error = -EINVAL;
 276
 277                 switch (arg) {
 278
 279                 case PMOPS_PREPARE:
 280                         data->platform_suspend = 1;
 281                         error = 0;
 282                         break;
 283
 284                 case PMOPS_ENTER:
 285                         if (data->platform_suspend)
 286                                 error = hibernation_platform_enter();
 287
 288                         break;
 289
 290                 case PMOPS_FINISH:
 291                         if (data->platform_suspend)
 292                                 error = 0;
 293
 294                         break;
 295
 296                 default:
 297                         printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
 298
 299                 }
 300                 break;
 301
 302         case SNAPSHOT_SET_SWAP_AREA:
 303                 if (swsusp_swap_in_use()) {
 304                         error = -EPERM;
 305                 } else {
 306                         struct resume_swap_area swap_area;
 307                         dev_t swdev;
 308
 309                         error = copy_from_user(&swap_area, (void __user *)arg,
 310                                         sizeof(struct resume_swap_area));
 311                         if (error) {
 312                                 error = -EFAULT;
 313                                 break;
 314                         }
 315
 316                         /*
 317                          * User space encodes device types as two-byte values,
 318                          * so we need to recode them
 319                          */
 320                         swdev = old_decode_dev(swap_area.dev);
 321                         if (swdev) {
 322                                 offset = swap_area.offset;
 323                                 data->swap = swap_type_of(swdev, offset, NULL);
 324                                 if (data->swap < 0)
 325                                         error = -ENODEV;
 326                         } else {
 327                                 data->swap = -1;
 328                                 error = -EINVAL;
 329                         }
 330                 }
 331                 break;
 332
 333         default:
 334                 error = -ENOTTY;
 335
 336         }
 337
 338         return error;
 339 }
 340
 341 static const struct file_operations snapshot_fops = {
 342         .open = snapshot_open,
 343         .release = snapshot_release,
 344         .read = snapshot_read,
 345         .write = snapshot_write,
 346         .llseek = no_llseek,
 347         .ioctl = snapshot_ioctl,
 348 };
 349
 350 static struct miscdevice snapshot_device = {
 351         .minor = SNAPSHOT_MINOR,
 352         .name = "snapshot",
 353         .fops = &snapshot_fops,
 354 };
 355
 356 static int __init snapshot_device_init(void)
 357 {
 358         return misc_register(&snapshot_device);
 359 };
 360
 361 device_initcall(snapshot_device_init);