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 #include <scsi/scsi_scan.h>
  27
  28 #include <asm/uaccess.h>
  29
  30 #include "power.h"
  31
  32 /*
  33  * NOTE: The SNAPSHOT_SET_SWAP_FILE and SNAPSHOT_PMOPS ioctls are obsolete and
  34  * will be removed in the future.  They are only preserved here for
  35  * compatibility with existing userland utilities.
  36  */
  37 #define SNAPSHOT_SET_SWAP_FILE  _IOW(SNAPSHOT_IOC_MAGIC, 10, unsigned int)
  38 #define SNAPSHOT_PMOPS          _IOW(SNAPSHOT_IOC_MAGIC, 12, unsigned int)
  39
  40 #define PMOPS_PREPARE   1
  41 #define PMOPS_ENTER     2
  42 #define PMOPS_FINISH    3
  43
  44 /*
  45  * NOTE: The following ioctl definitions are wrong and have been replaced with
  46  * correct ones.  They are only preserved here for compatibility with existing
  47  * userland utilities and will be removed in the future.
  48  */
  49 #define SNAPSHOT_ATOMIC_SNAPSHOT        _IOW(SNAPSHOT_IOC_MAGIC, 3, void *)
  50 #define SNAPSHOT_SET_IMAGE_SIZE         _IOW(SNAPSHOT_IOC_MAGIC, 6, unsigned long)
  51 #define SNAPSHOT_AVAIL_SWAP             _IOR(SNAPSHOT_IOC_MAGIC, 7, void *)
  52 #define SNAPSHOT_GET_SWAP_PAGE          _IOR(SNAPSHOT_IOC_MAGIC, 8, void *)
  53
  54
  55 #define SNAPSHOT_MINOR  231
  56
  57 static struct snapshot_data {
  58         struct snapshot_handle handle;
  59         int swap;
  60         int mode;
  61         char frozen;
  62         char ready;
  63         char platform_support;
  64 } snapshot_state;
  65
  66 atomic_t snapshot_device_available = ATOMIC_INIT(1);
  67
  68 static int snapshot_open(struct inode *inode, struct file *filp)
  69 {
  70         struct snapshot_data *data;
  71         int error;
  72
  73         mutex_lock(&pm_mutex);
  74
  75         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
  76                 error = -EBUSY;
  77                 goto Unlock;
  78         }
  79
  80         if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
  81                 atomic_inc(&snapshot_device_available);
  82                 error = -ENOSYS;
  83                 goto Unlock;
  84         }
  85         if(create_basic_memory_bitmaps()) {
  86                 atomic_inc(&snapshot_device_available);
  87                 error = -ENOMEM;
  88                 goto Unlock;
  89         }
  90         nonseekable_open(inode, filp);
  91         data = &snapshot_state;
  92         filp->private_data = data;
  93         memset(&data->handle, 0, sizeof(struct snapshot_handle));
  94         if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
  95                 /* Hibernating.  The image device should be accessible. */
  96                 data->swap = swsusp_resume_device ?
  97                         swap_type_of(swsusp_resume_device, 0, NULL) : -1;
  98                 data->mode = O_RDONLY;
  99                 error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
 100                 if (error)
 101                         pm_notifier_call_chain(PM_POST_HIBERNATION);
 102         } else {
 103                 /*
 104                  * Resuming.  We may need to wait for the image device to
 105                  * appear.
 106                  */
 107                 wait_for_device_probe();
 108                 scsi_complete_async_scans();
 109
 110                 data->swap = -1;
 111                 data->mode = O_WRONLY;
 112                 error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
 113                 if (error)
 114                         pm_notifier_call_chain(PM_POST_RESTORE);
 115         }
 116         if (error)
 117                 atomic_inc(&snapshot_device_available);
 118         data->frozen = 0;
 119         data->ready = 0;
 120         data->platform_support = 0;
 121
 122  Unlock:
 123         mutex_unlock(&pm_mutex);
 124
 125         return error;
 126 }
 127
 128 static int snapshot_release(struct inode *inode, struct file *filp)
 129 {
 130         struct snapshot_data *data;
 131
 132         mutex_lock(&pm_mutex);
 133
 134         swsusp_free();
 135         free_basic_memory_bitmaps();
 136         data = filp->private_data;
 137         free_all_swap_pages(data->swap);
 138         if (data->frozen)
 139                 thaw_processes();
 140         pm_notifier_call_chain(data->mode == O_WRONLY ?
 141                         PM_POST_HIBERNATION : PM_POST_RESTORE);
 142         atomic_inc(&snapshot_device_available);
 143
 144         mutex_unlock(&pm_mutex);
 145
 146         return 0;
 147 }
 148
 149 static ssize_t snapshot_read(struct file *filp, char __user *buf,
 150                              size_t count, loff_t *offp)
 151 {
 152         struct snapshot_data *data;
 153         ssize_t res;
 154
 155         mutex_lock(&pm_mutex);
 156
 157         data = filp->private_data;
 158         if (!data->ready) {
 159                 res = -ENODATA;
 160                 goto Unlock;
 161         }
 162         res = snapshot_read_next(&data->handle, count);
 163         if (res > 0) {
 164                 if (copy_to_user(buf, data_of(data->handle), res))
 165                         res = -EFAULT;
 166                 else
 167                         *offp = data->handle.offset;
 168         }
 169
 170  Unlock:
 171         mutex_unlock(&pm_mutex);
 172
 173         return res;
 174 }
 175
 176 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
 177                               size_t count, loff_t *offp)
 178 {
 179         struct snapshot_data *data;
 180         ssize_t res;
 181
 182         mutex_lock(&pm_mutex);
 183
 184         data = filp->private_data;
 185         res = snapshot_write_next(&data->handle, count);
 186         if (res > 0) {
 187                 if (copy_from_user(data_of(data->handle), buf, res))
 188                         res = -EFAULT;
 189                 else
 190                         *offp = data->handle.offset;
 191         }
 192
 193         mutex_unlock(&pm_mutex);
 194
 195         return res;
 196 }
 197
 198 static void snapshot_deprecated_ioctl(unsigned int cmd)
 199 {
 200         if (printk_ratelimit())
 201                 printk(KERN_NOTICE "%pf: ioctl '%.8x' is deprecated and will "
 202                                 "be removed soon, update your suspend-to-disk "
 203                                 "utilities\n",
 204                                 __builtin_return_address(0), cmd);
 205 }
 206
 207 static long snapshot_ioctl(struct file *filp, unsigned int cmd,
 208                                                         unsigned long arg)
 209 {
 210         int error = 0;
 211         struct snapshot_data *data;
 212         loff_t size;
 213         sector_t offset;
 214
 215         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
 216                 return -ENOTTY;
 217         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
 218                 return -ENOTTY;
 219         if (!capable(CAP_SYS_ADMIN))
 220                 return -EPERM;
 221
 222         if (!mutex_trylock(&pm_mutex))
 223                 return -EBUSY;
 224
 225         data = filp->private_data;
 226
 227         switch (cmd) {
 228
 229         case SNAPSHOT_FREEZE:
 230                 if (data->frozen)
 231                         break;
 232
 233                 printk("Syncing filesystems ... ");
 234                 sys_sync();
 235                 printk("done.\n");
 236
 237                 error = usermodehelper_disable();
 238                 if (error)
 239                         break;
 240
 241                 error = freeze_processes();
 242                 if (error) {
 243                         thaw_processes();
 244                         usermodehelper_enable();
 245                 }
 246                 if (!error)
 247                         data->frozen = 1;
 248                 break;
 249
 250         case SNAPSHOT_UNFREEZE:
 251                 if (!data->frozen || data->ready)
 252                         break;
 253                 thaw_processes();
 254                 usermodehelper_enable();
 255                 data->frozen = 0;
 256                 break;
 257
 258         case SNAPSHOT_ATOMIC_SNAPSHOT:
 259                 snapshot_deprecated_ioctl(cmd);
 260         case SNAPSHOT_CREATE_IMAGE:
 261                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
 262                         error = -EPERM;
 263                         break;
 264                 }
 265                 error = hibernation_snapshot(data->platform_support);
 266                 if (!error)
 267                         error = put_user(in_suspend, (int __user *)arg);
 268                 if (!error)
 269                         data->ready = 1;
 270                 break;
 271
 272         case SNAPSHOT_ATOMIC_RESTORE:
 273                 snapshot_write_finalize(&data->handle);
 274                 if (data->mode != O_WRONLY || !data->frozen ||
 275                     !snapshot_image_loaded(&data->handle)) {
 276                         error = -EPERM;
 277                         break;
 278                 }
 279                 error = hibernation_restore(data->platform_support);
 280                 break;
 281
 282         case SNAPSHOT_FREE:
 283                 swsusp_free();
 284                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
 285                 data->ready = 0;
 286                 break;
 287
 288         case SNAPSHOT_SET_IMAGE_SIZE:
 289                 snapshot_deprecated_ioctl(cmd);
 290         case SNAPSHOT_PREF_IMAGE_SIZE:
 291                 image_size = arg;
 292                 break;
 293
 294         case SNAPSHOT_GET_IMAGE_SIZE:
 295                 if (!data->ready) {
 296                         error = -ENODATA;
 297                         break;
 298                 }
 299                 size = snapshot_get_image_size();
 300                 size <<= PAGE_SHIFT;
 301                 error = put_user(size, (loff_t __user *)arg);
 302                 break;
 303
 304         case SNAPSHOT_AVAIL_SWAP:
 305                 snapshot_deprecated_ioctl(cmd);
 306         case SNAPSHOT_AVAIL_SWAP_SIZE:
 307                 size = count_swap_pages(data->swap, 1);
 308                 size <<= PAGE_SHIFT;
 309                 error = put_user(size, (loff_t __user *)arg);
 310                 break;
 311
 312         case SNAPSHOT_GET_SWAP_PAGE:
 313                 snapshot_deprecated_ioctl(cmd);
 314         case SNAPSHOT_ALLOC_SWAP_PAGE:
 315                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 316                         error = -ENODEV;
 317                         break;
 318                 }
 319                 offset = alloc_swapdev_block(data->swap);
 320                 if (offset) {
 321                         offset <<= PAGE_SHIFT;
 322                         error = put_user(offset, (loff_t __user *)arg);
 323                 } else {
 324                         error = -ENOSPC;
 325                 }
 326                 break;
 327
 328         case SNAPSHOT_FREE_SWAP_PAGES:
 329                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 330                         error = -ENODEV;
 331                         break;
 332                 }
 333                 free_all_swap_pages(data->swap);
 334                 break;
 335
 336         case SNAPSHOT_SET_SWAP_FILE: /* This ioctl is deprecated */
 337                 snapshot_deprecated_ioctl(cmd);
 338                 if (!swsusp_swap_in_use()) {
 339                         /*
 340                          * User space encodes device types as two-byte values,
 341                          * so we need to recode them
 342                          */
 343                         if (old_decode_dev(arg)) {
 344                                 data->swap = swap_type_of(old_decode_dev(arg),
 345                                                         0, NULL);
 346                                 if (data->swap < 0)
 347                                         error = -ENODEV;
 348                         } else {
 349                                 data->swap = -1;
 350                                 error = -EINVAL;
 351                         }
 352                 } else {
 353                         error = -EPERM;
 354                 }
 355                 break;
 356
 357         case SNAPSHOT_S2RAM:
 358                 if (!data->frozen) {
 359                         error = -EPERM;
 360                         break;
 361                 }
 362                 /*
 363                  * Tasks are frozen and the notifiers have been called with
 364                  * PM_HIBERNATION_PREPARE
 365                  */
 366                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 367                 break;
 368
 369         case SNAPSHOT_PLATFORM_SUPPORT:
 370                 data->platform_support = !!arg;
 371                 break;
 372
 373         case SNAPSHOT_POWER_OFF:
 374                 if (data->platform_support)
 375                         error = hibernation_platform_enter();
 376                 break;
 377
 378         case SNAPSHOT_PMOPS: /* This ioctl is deprecated */
 379                 snapshot_deprecated_ioctl(cmd);
 380                 error = -EINVAL;
 381
 382                 switch (arg) {
 383
 384                 case PMOPS_PREPARE:
 385                         data->platform_support = 1;
 386                         error = 0;
 387                         break;
 388
 389                 case PMOPS_ENTER:
 390                         if (data->platform_support)
 391                                 error = hibernation_platform_enter();
 392                         break;
 393
 394                 case PMOPS_FINISH:
 395                         if (data->platform_support)
 396                                 error = 0;
 397                         break;
 398
 399                 default:
 400                         printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
 401
 402                 }
 403                 break;
 404
 405         case SNAPSHOT_SET_SWAP_AREA:
 406                 if (swsusp_swap_in_use()) {
 407                         error = -EPERM;
 408                 } else {
 409                         struct resume_swap_area swap_area;
 410                         dev_t swdev;
 411
 412                         error = copy_from_user(&swap_area, (void __user *)arg,
 413                                         sizeof(struct resume_swap_area));
 414                         if (error) {
 415                                 error = -EFAULT;
 416                                 break;
 417                         }
 418
 419                         /*
 420                          * User space encodes device types as two-byte values,
 421                          * so we need to recode them
 422                          */
 423                         swdev = old_decode_dev(swap_area.dev);
 424                         if (swdev) {
 425                                 offset = swap_area.offset;
 426                                 data->swap = swap_type_of(swdev, offset, NULL);
 427                                 if (data->swap < 0)
 428                                         error = -ENODEV;
 429                         } else {
 430                                 data->swap = -1;
 431                                 error = -EINVAL;
 432                         }
 433                 }
 434                 break;
 435
 436         default:
 437                 error = -ENOTTY;
 438
 439         }
 440
 441         mutex_unlock(&pm_mutex);
 442
 443         return error;
 444 }
 445
 446 static const struct file_operations snapshot_fops = {
 447         .open = snapshot_open,
 448         .release = snapshot_release,
 449         .read = snapshot_read,
 450         .write = snapshot_write,
 451         .llseek = no_llseek,
 452         .unlocked_ioctl = snapshot_ioctl,
 453 };
 454
 455 static struct miscdevice snapshot_device = {
 456         .minor = SNAPSHOT_MINOR,
 457         .name = "snapshot",
 458         .fops = &snapshot_fops,
 459 };
 460
 461 static int __init snapshot_device_init(void)
 462 {
 463         return misc_register(&snapshot_device);
 464 };
 465
 466 device_initcall(snapshot_device_init);