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         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                 thaw_processes();
 267                 usermodehelper_enable();
 268                 data->frozen = 0;
 269                 break;
 270
 271         case SNAPSHOT_ATOMIC_SNAPSHOT:
 272                 snapshot_deprecated_ioctl(cmd);
 273         case SNAPSHOT_CREATE_IMAGE:
 274                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
 275                         error = -EPERM;
 276                         break;
 277                 }
 278                 error = hibernation_snapshot(data->platform_support);
 279                 if (!error)
 280                         error = put_user(in_suspend, (int __user *)arg);
 281                 if (!error)
 282                         data->ready = 1;
 283                 break;
 284
 285         case SNAPSHOT_ATOMIC_RESTORE:
 286                 snapshot_write_finalize(&data->handle);
 287                 if (data->mode != O_WRONLY || !data->frozen ||
 288                     !snapshot_image_loaded(&data->handle)) {
 289                         error = -EPERM;
 290                         break;
 291                 }
 292                 error = hibernation_restore(data->platform_support);
 293                 break;
 294
 295         case SNAPSHOT_FREE:
 296                 swsusp_free();
 297                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
 298                 data->ready = 0;
 299                 break;
 300
 301         case SNAPSHOT_SET_IMAGE_SIZE:
 302                 snapshot_deprecated_ioctl(cmd);
 303         case SNAPSHOT_PREF_IMAGE_SIZE:
 304                 image_size = arg;
 305                 break;
 306
 307         case SNAPSHOT_GET_IMAGE_SIZE:
 308                 if (!data->ready) {
 309                         error = -ENODATA;
 310                         break;
 311                 }
 312                 size = snapshot_get_image_size();
 313                 size <<= PAGE_SHIFT;
 314                 error = put_user(size, (loff_t __user *)arg);
 315                 break;
 316
 317         case SNAPSHOT_AVAIL_SWAP:
 318                 snapshot_deprecated_ioctl(cmd);
 319         case SNAPSHOT_AVAIL_SWAP_SIZE:
 320                 size = count_swap_pages(data->swap, 1);
 321                 size <<= PAGE_SHIFT;
 322                 error = put_user(size, (loff_t __user *)arg);
 323                 break;
 324
 325         case SNAPSHOT_GET_SWAP_PAGE:
 326                 snapshot_deprecated_ioctl(cmd);
 327         case SNAPSHOT_ALLOC_SWAP_PAGE:
 328                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 329                         error = -ENODEV;
 330                         break;
 331                 }
 332                 offset = alloc_swapdev_block(data->swap);
 333                 if (offset) {
 334                         offset <<= PAGE_SHIFT;
 335                         error = put_user(offset, (loff_t __user *)arg);
 336                 } else {
 337                         error = -ENOSPC;
 338                 }
 339                 break;
 340
 341         case SNAPSHOT_FREE_SWAP_PAGES:
 342                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 343                         error = -ENODEV;
 344                         break;
 345                 }
 346                 free_all_swap_pages(data->swap);
 347                 break;
 348
 349         case SNAPSHOT_SET_SWAP_FILE: /* This ioctl is deprecated */
 350                 snapshot_deprecated_ioctl(cmd);
 351                 if (!swsusp_swap_in_use()) {
 352                         /*
 353                          * User space encodes device types as two-byte values,
 354                          * so we need to recode them
 355                          */
 356                         if (old_decode_dev(arg)) {
 357                                 data->swap = swap_type_of(old_decode_dev(arg),
 358                                                         0, NULL);
 359                                 if (data->swap < 0)
 360                                         error = -ENODEV;
 361                         } else {
 362                                 data->swap = -1;
 363                                 error = -EINVAL;
 364                         }
 365                 } else {
 366                         error = -EPERM;
 367                 }
 368                 break;
 369
 370         case SNAPSHOT_S2RAM:
 371                 if (!data->frozen) {
 372                         error = -EPERM;
 373                         break;
 374                 }
 375                 /*
 376                  * Tasks are frozen and the notifiers have been called with
 377                  * PM_HIBERNATION_PREPARE
 378                  */
 379                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 380                 break;
 381
 382         case SNAPSHOT_PLATFORM_SUPPORT:
 383                 data->platform_support = !!arg;
 384                 break;
 385
 386         case SNAPSHOT_POWER_OFF:
 387                 if (data->platform_support)
 388                         error = hibernation_platform_enter();
 389                 break;
 390
 391         case SNAPSHOT_PMOPS: /* This ioctl is deprecated */
 392                 snapshot_deprecated_ioctl(cmd);
 393                 error = -EINVAL;
 394
 395                 switch (arg) {
 396
 397                 case PMOPS_PREPARE:
 398                         data->platform_support = 1;
 399                         error = 0;
 400                         break;
 401
 402                 case PMOPS_ENTER:
 403                         if (data->platform_support)
 404                                 error = hibernation_platform_enter();
 405                         break;
 406
 407                 case PMOPS_FINISH:
 408                         if (data->platform_support)
 409                                 error = 0;
 410                         break;
 411
 412                 default:
 413                         printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
 414
 415                 }
 416                 break;
 417
 418         case SNAPSHOT_SET_SWAP_AREA:
 419                 if (swsusp_swap_in_use()) {
 420                         error = -EPERM;
 421                 } else {
 422                         struct resume_swap_area swap_area;
 423                         dev_t swdev;
 424
 425                         error = copy_from_user(&swap_area, (void __user *)arg,
 426                                         sizeof(struct resume_swap_area));
 427                         if (error) {
 428                                 error = -EFAULT;
 429                                 break;
 430                         }
 431
 432                         /*
 433                          * User space encodes device types as two-byte values,
 434                          * so we need to recode them
 435                          */
 436                         swdev = new_decode_dev(swap_area.dev);
 437                         if (swdev) {
 438                                 offset = swap_area.offset;
 439                                 data->swap = swap_type_of(swdev, offset, NULL);
 440                                 if (data->swap < 0)
 441                                         error = -ENODEV;
 442                         } else {
 443                                 data->swap = -1;
 444                                 error = -EINVAL;
 445                         }
 446                 }
 447                 break;
 448
 449         default:
 450                 error = -ENOTTY;
 451
 452         }
 453
 454         mutex_unlock(&pm_mutex);
 455
 456         return error;
 457 }
 458
 459 static const struct file_operations snapshot_fops = {
 460         .open = snapshot_open,
 461         .release = snapshot_release,
 462         .read = snapshot_read,
 463         .write = snapshot_write,
 464         .llseek = no_llseek,
 465         .unlocked_ioctl = snapshot_ioctl,
 466 };
 467
 468 static struct miscdevice snapshot_device = {
 469         .minor = SNAPSHOT_MINOR,
 470         .name = "snapshot",
 471         .fops = &snapshot_fops,
 472 };
 473
 474 static int __init snapshot_device_init(void)
 475 {
 476         return misc_register(&snapshot_device);
 477 };
 478
 479 device_initcall(snapshot_device_init);