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 /*
  32  * NOTE: The SNAPSHOT_SET_SWAP_FILE and SNAPSHOT_PMOPS ioctls are obsolete and
  33  * will be removed in the future.  They are only preserved here for
  34  * compatibility with existing userland utilities.
  35  */
  36 #define SNAPSHOT_SET_SWAP_FILE  _IOW(SNAPSHOT_IOC_MAGIC, 10, unsigned int)
  37 #define SNAPSHOT_PMOPS          _IOW(SNAPSHOT_IOC_MAGIC, 12, unsigned int)
  38
  39 #define PMOPS_PREPARE   1
  40 #define PMOPS_ENTER     2
  41 #define PMOPS_FINISH    3
  42
  43 /*
  44  * NOTE: The following ioctl definitions are wrong and have been replaced with
  45  * correct ones.  They are only preserved here for compatibility with existing
  46  * userland utilities and will be removed in the future.
  47  */
  48 #define SNAPSHOT_ATOMIC_SNAPSHOT        _IOW(SNAPSHOT_IOC_MAGIC, 3, void *)
  49 #define SNAPSHOT_SET_IMAGE_SIZE         _IOW(SNAPSHOT_IOC_MAGIC, 6, unsigned long)
  50 #define SNAPSHOT_AVAIL_SWAP             _IOR(SNAPSHOT_IOC_MAGIC, 7, void *)
  51 #define SNAPSHOT_GET_SWAP_PAGE          _IOR(SNAPSHOT_IOC_MAGIC, 8, void *)
  52
  53
  54 #define SNAPSHOT_MINOR  231
  55
  56 static struct snapshot_data {
  57         struct snapshot_handle handle;
  58         int swap;
  59         int mode;
  60         char frozen;
  61         char ready;
  62         char platform_support;
  63 } snapshot_state;
  64
  65 atomic_t snapshot_device_available = ATOMIC_INIT(1);
  66
  67 static int snapshot_open(struct inode *inode, struct file *filp)
  68 {
  69         struct snapshot_data *data;
  70         int error;
  71
  72         if (!atomic_add_unless(&snapshot_device_available, -1, 0))
  73                 return -EBUSY;
  74
  75         if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
  76                 atomic_inc(&snapshot_device_available);
  77                 return -ENOSYS;
  78         }
  79         if(create_basic_memory_bitmaps()) {
  80                 atomic_inc(&snapshot_device_available);
  81                 return -ENOMEM;
  82         }
  83         nonseekable_open(inode, filp);
  84         data = &snapshot_state;
  85         filp->private_data = data;
  86         memset(&data->handle, 0, sizeof(struct snapshot_handle));
  87         if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
  88                 data->swap = swsusp_resume_device ?
  89                         swap_type_of(swsusp_resume_device, 0, NULL) : -1;
  90                 data->mode = O_RDONLY;
  91                 error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
  92                 if (error)
  93                         pm_notifier_call_chain(PM_POST_RESTORE);
  94         } else {
  95                 data->swap = -1;
  96                 data->mode = O_WRONLY;
  97                 error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
  98                 if (error)
  99                         pm_notifier_call_chain(PM_POST_HIBERNATION);
 100         }
 101         if (error) {
 102                 atomic_inc(&snapshot_device_available);
 103                 return error;
 104         }
 105         data->frozen = 0;
 106         data->ready = 0;
 107         data->platform_support = 0;
 108
 109         return 0;
 110 }
 111
 112 static int snapshot_release(struct inode *inode, struct file *filp)
 113 {
 114         struct snapshot_data *data;
 115
 116         swsusp_free();
 117         free_basic_memory_bitmaps();
 118         data = filp->private_data;
 119         free_all_swap_pages(data->swap);
 120         if (data->frozen) {
 121                 mutex_lock(&pm_mutex);
 122                 thaw_processes();
 123                 mutex_unlock(&pm_mutex);
 124         }
 125         pm_notifier_call_chain(data->mode == O_WRONLY ?
 126                         PM_POST_HIBERNATION : PM_POST_RESTORE);
 127         atomic_inc(&snapshot_device_available);
 128         return 0;
 129 }
 130
 131 static ssize_t snapshot_read(struct file *filp, char __user *buf,
 132                              size_t count, loff_t *offp)
 133 {
 134         struct snapshot_data *data;
 135         ssize_t res;
 136
 137         data = filp->private_data;
 138         if (!data->ready)
 139                 return -ENODATA;
 140         res = snapshot_read_next(&data->handle, count);
 141         if (res > 0) {
 142                 if (copy_to_user(buf, data_of(data->handle), res))
 143                         res = -EFAULT;
 144                 else
 145                         *offp = data->handle.offset;
 146         }
 147         return res;
 148 }
 149
 150 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
 151                               size_t count, loff_t *offp)
 152 {
 153         struct snapshot_data *data;
 154         ssize_t res;
 155
 156         data = filp->private_data;
 157         res = snapshot_write_next(&data->handle, count);
 158         if (res > 0) {
 159                 if (copy_from_user(data_of(data->handle), buf, res))
 160                         res = -EFAULT;
 161                 else
 162                         *offp = data->handle.offset;
 163         }
 164         return res;
 165 }
 166
 167 static int snapshot_ioctl(struct inode *inode, struct file *filp,
 168                           unsigned int cmd, unsigned long arg)
 169 {
 170         int error = 0;
 171         struct snapshot_data *data;
 172         loff_t size;
 173         sector_t offset;
 174
 175         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
 176                 return -ENOTTY;
 177         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
 178                 return -ENOTTY;
 179         if (!capable(CAP_SYS_ADMIN))
 180                 return -EPERM;
 181
 182         data = filp->private_data;
 183
 184         switch (cmd) {
 185
 186         case SNAPSHOT_FREEZE:
 187                 if (data->frozen)
 188                         break;
 189                 mutex_lock(&pm_mutex);
 190                 printk("Syncing filesystems ... ");
 191                 sys_sync();
 192                 printk("done.\n");
 193
 194                 error = freeze_processes();
 195                 if (error)
 196                         thaw_processes();
 197                 mutex_unlock(&pm_mutex);
 198                 if (!error)
 199                         data->frozen = 1;
 200                 break;
 201
 202         case SNAPSHOT_UNFREEZE:
 203                 if (!data->frozen || data->ready)
 204                         break;
 205                 mutex_lock(&pm_mutex);
 206                 thaw_processes();
 207                 mutex_unlock(&pm_mutex);
 208                 data->frozen = 0;
 209                 break;
 210
 211         case SNAPSHOT_CREATE_IMAGE:
 212         case SNAPSHOT_ATOMIC_SNAPSHOT:
 213                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
 214                         error = -EPERM;
 215                         break;
 216                 }
 217                 error = hibernation_snapshot(data->platform_support);
 218                 if (!error)
 219                         error = put_user(in_suspend, (int __user *)arg);
 220                 if (!error)
 221                         data->ready = 1;
 222                 break;
 223
 224         case SNAPSHOT_ATOMIC_RESTORE:
 225                 snapshot_write_finalize(&data->handle);
 226                 if (data->mode != O_WRONLY || !data->frozen ||
 227                     !snapshot_image_loaded(&data->handle)) {
 228                         error = -EPERM;
 229                         break;
 230                 }
 231                 error = hibernation_restore(data->platform_support);
 232                 break;
 233
 234         case SNAPSHOT_FREE:
 235                 swsusp_free();
 236                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
 237                 data->ready = 0;
 238                 break;
 239
 240         case SNAPSHOT_PREF_IMAGE_SIZE:
 241         case SNAPSHOT_SET_IMAGE_SIZE:
 242                 image_size = arg;
 243                 break;
 244
 245         case SNAPSHOT_GET_IMAGE_SIZE:
 246                 if (!data->ready) {
 247                         error = -ENODATA;
 248                         break;
 249                 }
 250                 size = snapshot_get_image_size();
 251                 size <<= PAGE_SHIFT;
 252                 error = put_user(size, (loff_t __user *)arg);
 253                 break;
 254
 255         case SNAPSHOT_AVAIL_SWAP_SIZE:
 256         case SNAPSHOT_AVAIL_SWAP:
 257                 size = count_swap_pages(data->swap, 1);
 258                 size <<= PAGE_SHIFT;
 259                 error = put_user(size, (loff_t __user *)arg);
 260                 break;
 261
 262         case SNAPSHOT_ALLOC_SWAP_PAGE:
 263         case SNAPSHOT_GET_SWAP_PAGE:
 264                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 265                         error = -ENODEV;
 266                         break;
 267                 }
 268                 offset = alloc_swapdev_block(data->swap);
 269                 if (offset) {
 270                         offset <<= PAGE_SHIFT;
 271                         error = put_user(offset, (loff_t __user *)arg);
 272                 } else {
 273                         error = -ENOSPC;
 274                 }
 275                 break;
 276
 277         case SNAPSHOT_FREE_SWAP_PAGES:
 278                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 279                         error = -ENODEV;
 280                         break;
 281                 }
 282                 free_all_swap_pages(data->swap);
 283                 break;
 284
 285         case SNAPSHOT_SET_SWAP_FILE: /* This ioctl is deprecated */
 286                 if (!swsusp_swap_in_use()) {
 287                         /*
 288                          * User space encodes device types as two-byte values,
 289                          * so we need to recode them
 290                          */
 291                         if (old_decode_dev(arg)) {
 292                                 data->swap = swap_type_of(old_decode_dev(arg),
 293                                                         0, NULL);
 294                                 if (data->swap < 0)
 295                                         error = -ENODEV;
 296                         } else {
 297                                 data->swap = -1;
 298                                 error = -EINVAL;
 299                         }
 300                 } else {
 301                         error = -EPERM;
 302                 }
 303                 break;
 304
 305         case SNAPSHOT_S2RAM:
 306                 if (!data->frozen) {
 307                         error = -EPERM;
 308                         break;
 309                 }
 310                 if (!mutex_trylock(&pm_mutex)) {
 311                         error = -EBUSY;
 312                         break;
 313                 }
 314                 /*
 315                  * Tasks are frozen and the notifiers have been called with
 316                  * PM_HIBERNATION_PREPARE
 317                  */
 318                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 319                 mutex_unlock(&pm_mutex);
 320                 break;
 321
 322         case SNAPSHOT_PLATFORM_SUPPORT:
 323                 data->platform_support = !!arg;
 324                 break;
 325
 326         case SNAPSHOT_POWER_OFF:
 327                 if (data->platform_support)
 328                         error = hibernation_platform_enter();
 329                 break;
 330
 331         case SNAPSHOT_PMOPS: /* This ioctl is deprecated */
 332                 error = -EINVAL;
 333
 334                 switch (arg) {
 335
 336                 case PMOPS_PREPARE:
 337                         data->platform_support = 1;
 338                         error = 0;
 339                         break;
 340
 341                 case PMOPS_ENTER:
 342                         if (data->platform_support)
 343                                 error = hibernation_platform_enter();
 344                         break;
 345
 346                 case PMOPS_FINISH:
 347                         if (data->platform_support)
 348                                 error = 0;
 349                         break;
 350
 351                 default:
 352                         printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
 353
 354                 }
 355                 break;
 356
 357         case SNAPSHOT_SET_SWAP_AREA:
 358                 if (swsusp_swap_in_use()) {
 359                         error = -EPERM;
 360                 } else {
 361                         struct resume_swap_area swap_area;
 362                         dev_t swdev;
 363
 364                         error = copy_from_user(&swap_area, (void __user *)arg,
 365                                         sizeof(struct resume_swap_area));
 366                         if (error) {
 367                                 error = -EFAULT;
 368                                 break;
 369                         }
 370
 371                         /*
 372                          * User space encodes device types as two-byte values,
 373                          * so we need to recode them
 374                          */
 375                         swdev = old_decode_dev(swap_area.dev);
 376                         if (swdev) {
 377                                 offset = swap_area.offset;
 378                                 data->swap = swap_type_of(swdev, offset, NULL);
 379                                 if (data->swap < 0)
 380                                         error = -ENODEV;
 381                         } else {
 382                                 data->swap = -1;
 383                                 error = -EINVAL;
 384                         }
 385                 }
 386                 break;
 387
 388         default:
 389                 error = -ENOTTY;
 390
 391         }
 392
 393         return error;
 394 }
 395
 396 static const struct file_operations snapshot_fops = {
 397         .open = snapshot_open,
 398         .release = snapshot_release,
 399         .read = snapshot_read,
 400         .write = snapshot_write,
 401         .llseek = no_llseek,
 402         .ioctl = snapshot_ioctl,
 403 };
 404
 405 static struct miscdevice snapshot_device = {
 406         .minor = SNAPSHOT_MINOR,
 407         .name = "snapshot",
 408         .fops = &snapshot_fops,
 409 };
 410
 411 static int __init snapshot_device_init(void)
 412 {
 413         return misc_register(&snapshot_device);
 414 };
 415
 416 device_initcall(snapshot_device_init);