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_RDONLY ?
 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 long snapshot_ioctl(struct file *filp, unsigned int cmd,
 199                                                         unsigned long arg)
 200 {
 201         int error = 0;
 202         struct snapshot_data *data;
 203         loff_t size;
 204         sector_t offset;
 205
 206         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
 207                 return -ENOTTY;
 208         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
 209                 return -ENOTTY;
 210         if (!capable(CAP_SYS_ADMIN))
 211                 return -EPERM;
 212
 213         if (!mutex_trylock(&pm_mutex))
 214                 return -EBUSY;
 215
 216         data = filp->private_data;
 217
 218         switch (cmd) {
 219
 220         case SNAPSHOT_FREEZE:
 221                 if (data->frozen)
 222                         break;
 223
 224                 printk("Syncing filesystems ... ");
 225                 sys_sync();
 226                 printk("done.\n");
 227
 228                 error = usermodehelper_disable();
 229                 if (error)
 230                         break;
 231
 232                 error = freeze_processes();
 233                 if (error) {
 234                         thaw_processes();
 235                         usermodehelper_enable();
 236                 }
 237                 if (!error)
 238                         data->frozen = 1;
 239                 break;
 240
 241         case SNAPSHOT_UNFREEZE:
 242                 if (!data->frozen || data->ready)
 243                         break;
 244                 thaw_processes();
 245                 usermodehelper_enable();
 246                 data->frozen = 0;
 247                 break;
 248
 249         case SNAPSHOT_CREATE_IMAGE:
 250         case SNAPSHOT_ATOMIC_SNAPSHOT:
 251                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
 252                         error = -EPERM;
 253                         break;
 254                 }
 255                 error = hibernation_snapshot(data->platform_support);
 256                 if (!error)
 257                         error = put_user(in_suspend, (int __user *)arg);
 258                 if (!error)
 259                         data->ready = 1;
 260                 break;
 261
 262         case SNAPSHOT_ATOMIC_RESTORE:
 263                 snapshot_write_finalize(&data->handle);
 264                 if (data->mode != O_WRONLY || !data->frozen ||
 265                     !snapshot_image_loaded(&data->handle)) {
 266                         error = -EPERM;
 267                         break;
 268                 }
 269                 error = hibernation_restore(data->platform_support);
 270                 break;
 271
 272         case SNAPSHOT_FREE:
 273                 swsusp_free();
 274                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
 275                 data->ready = 0;
 276                 break;
 277
 278         case SNAPSHOT_PREF_IMAGE_SIZE:
 279         case SNAPSHOT_SET_IMAGE_SIZE:
 280                 image_size = arg;
 281                 break;
 282
 283         case SNAPSHOT_GET_IMAGE_SIZE:
 284                 if (!data->ready) {
 285                         error = -ENODATA;
 286                         break;
 287                 }
 288                 size = snapshot_get_image_size();
 289                 size <<= PAGE_SHIFT;
 290                 error = put_user(size, (loff_t __user *)arg);
 291                 break;
 292
 293         case SNAPSHOT_AVAIL_SWAP_SIZE:
 294         case SNAPSHOT_AVAIL_SWAP:
 295                 size = count_swap_pages(data->swap, 1);
 296                 size <<= PAGE_SHIFT;
 297                 error = put_user(size, (loff_t __user *)arg);
 298                 break;
 299
 300         case SNAPSHOT_ALLOC_SWAP_PAGE:
 301         case SNAPSHOT_GET_SWAP_PAGE:
 302                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 303                         error = -ENODEV;
 304                         break;
 305                 }
 306                 offset = alloc_swapdev_block(data->swap);
 307                 if (offset) {
 308                         offset <<= PAGE_SHIFT;
 309                         error = put_user(offset, (loff_t __user *)arg);
 310                 } else {
 311                         error = -ENOSPC;
 312                 }
 313                 break;
 314
 315         case SNAPSHOT_FREE_SWAP_PAGES:
 316                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 317                         error = -ENODEV;
 318                         break;
 319                 }
 320                 free_all_swap_pages(data->swap);
 321                 break;
 322
 323         case SNAPSHOT_SET_SWAP_FILE: /* This ioctl is deprecated */
 324                 if (!swsusp_swap_in_use()) {
 325                         /*
 326                          * User space encodes device types as two-byte values,
 327                          * so we need to recode them
 328                          */
 329                         if (old_decode_dev(arg)) {
 330                                 data->swap = swap_type_of(old_decode_dev(arg),
 331                                                         0, NULL);
 332                                 if (data->swap < 0)
 333                                         error = -ENODEV;
 334                         } else {
 335                                 data->swap = -1;
 336                                 error = -EINVAL;
 337                         }
 338                 } else {
 339                         error = -EPERM;
 340                 }
 341                 break;
 342
 343         case SNAPSHOT_S2RAM:
 344                 if (!data->frozen) {
 345                         error = -EPERM;
 346                         break;
 347                 }
 348                 /*
 349                  * Tasks are frozen and the notifiers have been called with
 350                  * PM_HIBERNATION_PREPARE
 351                  */
 352                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 353                 break;
 354
 355         case SNAPSHOT_PLATFORM_SUPPORT:
 356                 data->platform_support = !!arg;
 357                 break;
 358
 359         case SNAPSHOT_POWER_OFF:
 360                 if (data->platform_support)
 361                         error = hibernation_platform_enter();
 362                 break;
 363
 364         case SNAPSHOT_PMOPS: /* This ioctl is deprecated */
 365                 error = -EINVAL;
 366
 367                 switch (arg) {
 368
 369                 case PMOPS_PREPARE:
 370                         data->platform_support = 1;
 371                         error = 0;
 372                         break;
 373
 374                 case PMOPS_ENTER:
 375                         if (data->platform_support)
 376                                 error = hibernation_platform_enter();
 377                         break;
 378
 379                 case PMOPS_FINISH:
 380                         if (data->platform_support)
 381                                 error = 0;
 382                         break;
 383
 384                 default:
 385                         printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
 386
 387                 }
 388                 break;
 389
 390         case SNAPSHOT_SET_SWAP_AREA:
 391                 if (swsusp_swap_in_use()) {
 392                         error = -EPERM;
 393                 } else {
 394                         struct resume_swap_area swap_area;
 395                         dev_t swdev;
 396
 397                         error = copy_from_user(&swap_area, (void __user *)arg,
 398                                         sizeof(struct resume_swap_area));
 399                         if (error) {
 400                                 error = -EFAULT;
 401                                 break;
 402                         }
 403
 404                         /*
 405                          * User space encodes device types as two-byte values,
 406                          * so we need to recode them
 407                          */
 408                         swdev = old_decode_dev(swap_area.dev);
 409                         if (swdev) {
 410                                 offset = swap_area.offset;
 411                                 data->swap = swap_type_of(swdev, offset, NULL);
 412                                 if (data->swap < 0)
 413                                         error = -ENODEV;
 414                         } else {
 415                                 data->swap = -1;
 416                                 error = -EINVAL;
 417                         }
 418                 }
 419                 break;
 420
 421         default:
 422                 error = -ENOTTY;
 423
 424         }
 425
 426         mutex_unlock(&pm_mutex);
 427
 428         return error;
 429 }
 430
 431 static const struct file_operations snapshot_fops = {
 432         .open = snapshot_open,
 433         .release = snapshot_release,
 434         .read = snapshot_read,
 435         .write = snapshot_write,
 436         .llseek = no_llseek,
 437         .unlocked_ioctl = snapshot_ioctl,
 438 };
 439
 440 static struct miscdevice snapshot_device = {
 441         .minor = SNAPSHOT_MINOR,
 442         .name = "snapshot",
 443         .fops = &snapshot_fops,
 444 };
 445
 446 static int __init snapshot_device_init(void)
 447 {
 448         return misc_register(&snapshot_device);
 449 };
 450
 451 device_initcall(snapshot_device_init);