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                 free_basic_memory_bitmaps();
 118                 atomic_inc(&snapshot_device_available);
 119         }
 120         data->frozen = 0;
 121         data->ready = 0;
 122         data->platform_support = 0;
 123
 124  Unlock:
 125         mutex_unlock(&pm_mutex);
 126
 127         return error;
 128 }
 129
 130 static int snapshot_release(struct inode *inode, struct file *filp)
 131 {
 132         struct snapshot_data *data;
 133
 134         mutex_lock(&pm_mutex);
 135
 136         swsusp_free();
 137         free_basic_memory_bitmaps();
 138         data = filp->private_data;
 139         free_all_swap_pages(data->swap);
 140         if (data->frozen) {
 141                 pm_restore_gfp_mask();
 142                 thaw_processes();
 143         }
 144         pm_notifier_call_chain(data->mode == O_RDONLY ?
 145                         PM_POST_HIBERNATION : PM_POST_RESTORE);
 146         atomic_inc(&snapshot_device_available);
 147
 148         mutex_unlock(&pm_mutex);
 149
 150         return 0;
 151 }
 152
 153 static ssize_t snapshot_read(struct file *filp, char __user *buf,
 154                              size_t count, loff_t *offp)
 155 {
 156         struct snapshot_data *data;
 157         ssize_t res;
 158         loff_t pg_offp = *offp & ~PAGE_MASK;
 159
 160         mutex_lock(&pm_mutex);
 161
 162         data = filp->private_data;
 163         if (!data->ready) {
 164                 res = -ENODATA;
 165                 goto Unlock;
 166         }
 167         if (!pg_offp) { /* on page boundary? */
 168                 res = snapshot_read_next(&data->handle);
 169                 if (res <= 0)
 170                         goto Unlock;
 171         } else {
 172                 res = PAGE_SIZE - pg_offp;
 173         }
 174
 175         res = simple_read_from_buffer(buf, count, &pg_offp,
 176                         data_of(data->handle), res);
 177         if (res > 0)
 178                 *offp += res;
 179
 180  Unlock:
 181         mutex_unlock(&pm_mutex);
 182
 183         return res;
 184 }
 185
 186 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
 187                               size_t count, loff_t *offp)
 188 {
 189         struct snapshot_data *data;
 190         ssize_t res;
 191         loff_t pg_offp = *offp & ~PAGE_MASK;
 192
 193         mutex_lock(&pm_mutex);
 194
 195         data = filp->private_data;
 196
 197         if (!pg_offp) {
 198                 res = snapshot_write_next(&data->handle);
 199                 if (res <= 0)
 200                         goto unlock;
 201         } else {
 202                 res = PAGE_SIZE - pg_offp;
 203         }
 204
 205         res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
 206                         buf, count);
 207         if (res > 0)
 208                 *offp += res;
 209 unlock:
 210         mutex_unlock(&pm_mutex);
 211
 212         return res;
 213 }
 214
 215 static void snapshot_deprecated_ioctl(unsigned int cmd)
 216 {
 217         if (printk_ratelimit())
 218                 printk(KERN_NOTICE "%pf: ioctl '%.8x' is deprecated and will "
 219                                 "be removed soon, update your suspend-to-disk "
 220                                 "utilities\n",
 221                                 __builtin_return_address(0), cmd);
 222 }
 223
 224 static long snapshot_ioctl(struct file *filp, unsigned int cmd,
 225                                                         unsigned long arg)
 226 {
 227         int error = 0;
 228         struct snapshot_data *data;
 229         loff_t size;
 230         sector_t offset;
 231
 232         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
 233                 return -ENOTTY;
 234         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
 235                 return -ENOTTY;
 236         if (!capable(CAP_SYS_ADMIN))
 237                 return -EPERM;
 238
 239         if (!mutex_trylock(&pm_mutex))
 240                 return -EBUSY;
 241
 242         data = filp->private_data;
 243
 244         switch (cmd) {
 245
 246         case SNAPSHOT_FREEZE:
 247                 if (data->frozen)
 248                         break;
 249
 250                 printk("Syncing filesystems ... ");
 251                 sys_sync();
 252                 printk("done.\n");
 253
 254                 error = usermodehelper_disable();
 255                 if (error)
 256                         break;
 257
 258                 error = freeze_processes();
 259                 if (error) {
 260                         thaw_processes();
 261                         usermodehelper_enable();
 262                 }
 263                 if (!error)
 264                         data->frozen = 1;
 265                 break;
 266
 267         case SNAPSHOT_UNFREEZE:
 268                 if (!data->frozen || data->ready)
 269                         break;
 270                 pm_restore_gfp_mask();
 271                 thaw_processes();
 272                 usermodehelper_enable();
 273                 data->frozen = 0;
 274                 break;
 275
 276         case SNAPSHOT_ATOMIC_SNAPSHOT:
 277                 snapshot_deprecated_ioctl(cmd);
 278         case SNAPSHOT_CREATE_IMAGE:
 279                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
 280                         error = -EPERM;
 281                         break;
 282                 }
 283                 pm_restore_gfp_mask();
 284                 error = hibernation_snapshot(data->platform_support);
 285                 if (!error)
 286                         error = put_user(in_suspend, (int __user *)arg);
 287                 if (!error)
 288                         data->ready = 1;
 289                 break;
 290
 291         case SNAPSHOT_ATOMIC_RESTORE:
 292                 snapshot_write_finalize(&data->handle);
 293                 if (data->mode != O_WRONLY || !data->frozen ||
 294                     !snapshot_image_loaded(&data->handle)) {
 295                         error = -EPERM;
 296                         break;
 297                 }
 298                 error = hibernation_restore(data->platform_support);
 299                 break;
 300
 301         case SNAPSHOT_FREE:
 302                 swsusp_free();
 303                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
 304                 data->ready = 0;
 305                 break;
 306
 307         case SNAPSHOT_SET_IMAGE_SIZE:
 308                 snapshot_deprecated_ioctl(cmd);
 309         case SNAPSHOT_PREF_IMAGE_SIZE:
 310                 image_size = arg;
 311                 break;
 312
 313         case SNAPSHOT_GET_IMAGE_SIZE:
 314                 if (!data->ready) {
 315                         error = -ENODATA;
 316                         break;
 317                 }
 318                 size = snapshot_get_image_size();
 319                 size <<= PAGE_SHIFT;
 320                 error = put_user(size, (loff_t __user *)arg);
 321                 break;
 322
 323         case SNAPSHOT_AVAIL_SWAP:
 324                 snapshot_deprecated_ioctl(cmd);
 325         case SNAPSHOT_AVAIL_SWAP_SIZE:
 326                 size = count_swap_pages(data->swap, 1);
 327                 size <<= PAGE_SHIFT;
 328                 error = put_user(size, (loff_t __user *)arg);
 329                 break;
 330
 331         case SNAPSHOT_GET_SWAP_PAGE:
 332                 snapshot_deprecated_ioctl(cmd);
 333         case SNAPSHOT_ALLOC_SWAP_PAGE:
 334                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 335                         error = -ENODEV;
 336                         break;
 337                 }
 338                 offset = alloc_swapdev_block(data->swap);
 339                 if (offset) {
 340                         offset <<= PAGE_SHIFT;
 341                         error = put_user(offset, (loff_t __user *)arg);
 342                 } else {
 343                         error = -ENOSPC;
 344                 }
 345                 break;
 346
 347         case SNAPSHOT_FREE_SWAP_PAGES:
 348                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 349                         error = -ENODEV;
 350                         break;
 351                 }
 352                 free_all_swap_pages(data->swap);
 353                 break;
 354
 355         case SNAPSHOT_SET_SWAP_FILE: /* This ioctl is deprecated */
 356                 snapshot_deprecated_ioctl(cmd);
 357                 if (!swsusp_swap_in_use()) {
 358                         /*
 359                          * User space encodes device types as two-byte values,
 360                          * so we need to recode them
 361                          */
 362                         if (old_decode_dev(arg)) {
 363                                 data->swap = swap_type_of(old_decode_dev(arg),
 364                                                         0, NULL);
 365                                 if (data->swap < 0)
 366                                         error = -ENODEV;
 367                         } else {
 368                                 data->swap = -1;
 369                                 error = -EINVAL;
 370                         }
 371                 } else {
 372                         error = -EPERM;
 373                 }
 374                 break;
 375
 376         case SNAPSHOT_S2RAM:
 377                 if (!data->frozen) {
 378                         error = -EPERM;
 379                         break;
 380                 }
 381                 /*
 382                  * Tasks are frozen and the notifiers have been called with
 383                  * PM_HIBERNATION_PREPARE
 384                  */
 385                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 386                 data->ready = 0;
 387                 break;
 388
 389         case SNAPSHOT_PLATFORM_SUPPORT:
 390                 data->platform_support = !!arg;
 391                 break;
 392
 393         case SNAPSHOT_POWER_OFF:
 394                 if (data->platform_support)
 395                         error = hibernation_platform_enter();
 396                 break;
 397
 398         case SNAPSHOT_PMOPS: /* This ioctl is deprecated */
 399                 snapshot_deprecated_ioctl(cmd);
 400                 error = -EINVAL;
 401
 402                 switch (arg) {
 403
 404                 case PMOPS_PREPARE:
 405                         data->platform_support = 1;
 406                         error = 0;
 407                         break;
 408
 409                 case PMOPS_ENTER:
 410                         if (data->platform_support)
 411                                 error = hibernation_platform_enter();
 412                         break;
 413
 414                 case PMOPS_FINISH:
 415                         if (data->platform_support)
 416                                 error = 0;
 417                         break;
 418
 419                 default:
 420                         printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
 421
 422                 }
 423                 break;
 424
 425         case SNAPSHOT_SET_SWAP_AREA:
 426                 if (swsusp_swap_in_use()) {
 427                         error = -EPERM;
 428                 } else {
 429                         struct resume_swap_area swap_area;
 430                         dev_t swdev;
 431
 432                         error = copy_from_user(&swap_area, (void __user *)arg,
 433                                         sizeof(struct resume_swap_area));
 434                         if (error) {
 435                                 error = -EFAULT;
 436                                 break;
 437                         }
 438
 439                         /*
 440                          * User space encodes device types as two-byte values,
 441                          * so we need to recode them
 442                          */
 443                         swdev = new_decode_dev(swap_area.dev);
 444                         if (swdev) {
 445                                 offset = swap_area.offset;
 446                                 data->swap = swap_type_of(swdev, offset, NULL);
 447                                 if (data->swap < 0)
 448                                         error = -ENODEV;
 449                         } else {
 450                                 data->swap = -1;
 451                                 error = -EINVAL;
 452                         }
 453                 }
 454                 break;
 455
 456         default:
 457                 error = -ENOTTY;
 458
 459         }
 460
 461         mutex_unlock(&pm_mutex);
 462
 463         return error;
 464 }
 465
 466 static const struct file_operations snapshot_fops = {
 467         .open = snapshot_open,
 468         .release = snapshot_release,
 469         .read = snapshot_read,
 470         .write = snapshot_write,
 471         .llseek = no_llseek,
 472         .unlocked_ioctl = snapshot_ioctl,
 473 };
 474
 475 static struct miscdevice snapshot_device = {
 476         .minor = SNAPSHOT_MINOR,
 477         .name = "snapshot",
 478         .fops = &snapshot_fops,
 479 };
 480
 481 static int __init snapshot_device_init(void)
 482 {
 483         return misc_register(&snapshot_device);
 484 };
 485
 486 device_initcall(snapshot_device_init);