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