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