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 <linux/smp_lock.h>
  27 #include <scsi/scsi_scan.h>
  28
  29 #include <asm/uaccess.h>
  30
  31 #include "power.h"
  32
  33 /*
  34  * NOTE: The SNAPSHOT_SET_SWAP_FILE and SNAPSHOT_PMOPS ioctls are obsolete and
  35  * will be removed in the future.  They are only preserved here for
  36  * compatibility with existing userland utilities.
  37  */
  38 #define SNAPSHOT_SET_SWAP_FILE  _IOW(SNAPSHOT_IOC_MAGIC, 10, unsigned int)
  39 #define SNAPSHOT_PMOPS          _IOW(SNAPSHOT_IOC_MAGIC, 12, unsigned int)
  40
  41 #define PMOPS_PREPARE   1
  42 #define PMOPS_ENTER     2
  43 #define PMOPS_FINISH    3
  44
  45 /*
  46  * NOTE: The following ioctl definitions are wrong and have been replaced with
  47  * correct ones.  They are only preserved here for compatibility with existing
  48  * userland utilities and will be removed in the future.
  49  */
  50 #define SNAPSHOT_ATOMIC_SNAPSHOT        _IOW(SNAPSHOT_IOC_MAGIC, 3, void *)
  51 #define SNAPSHOT_SET_IMAGE_SIZE         _IOW(SNAPSHOT_IOC_MAGIC, 6, unsigned long)
  52 #define SNAPSHOT_AVAIL_SWAP             _IOR(SNAPSHOT_IOC_MAGIC, 7, void *)
  53 #define SNAPSHOT_GET_SWAP_PAGE          _IOR(SNAPSHOT_IOC_MAGIC, 8, void *)
  54
  55
  56 #define SNAPSHOT_MINOR  231
  57
  58 static struct snapshot_data {
  59         struct snapshot_handle handle;
  60         int swap;
  61         int mode;
  62         char frozen;
  63         char ready;
  64         char platform_support;
  65 } snapshot_state;
  66
  67 atomic_t snapshot_device_available = ATOMIC_INIT(1);
  68
  69 static int snapshot_open(struct inode *inode, struct file *filp)
  70 {
  71         struct snapshot_data *data;
  72         int error;
  73
  74         mutex_lock(&pm_mutex);
  75
  76         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
  77                 error = -EBUSY;
  78                 goto Unlock;
  79         }
  80
  81         if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
  82                 atomic_inc(&snapshot_device_available);
  83                 error = -ENOSYS;
  84                 goto Unlock;
  85         }
  86         if(create_basic_memory_bitmaps()) {
  87                 atomic_inc(&snapshot_device_available);
  88                 error = -ENOMEM;
  89                 goto Unlock;
  90         }
  91         nonseekable_open(inode, filp);
  92         data = &snapshot_state;
  93         filp->private_data = data;
  94         memset(&data->handle, 0, sizeof(struct snapshot_handle));
  95         if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
  96                 /* Hibernating.  The image device should be accessible. */
  97                 data->swap = swsusp_resume_device ?
  98                         swap_type_of(swsusp_resume_device, 0, NULL) : -1;
  99                 data->mode = O_RDONLY;
 100                 error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
 101                 if (error)
 102                         pm_notifier_call_chain(PM_POST_HIBERNATION);
 103         } else {
 104                 /*
 105                  * Resuming.  We may need to wait for the image device to
 106                  * appear.
 107                  */
 108                 wait_for_device_probe();
 109                 scsi_complete_async_scans();
 110
 111                 data->swap = -1;
 112                 data->mode = O_WRONLY;
 113                 error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
 114                 if (error)
 115                         pm_notifier_call_chain(PM_POST_RESTORE);
 116         }
 117         if (error)
 118                 atomic_inc(&snapshot_device_available);
 119         data->frozen = 0;
 120         data->ready = 0;
 121         data->platform_support = 0;
 122
 123  Unlock:
 124         mutex_unlock(&pm_mutex);
 125
 126         return error;
 127 }
 128
 129 static int snapshot_release(struct inode *inode, struct file *filp)
 130 {
 131         struct snapshot_data *data;
 132
 133         mutex_lock(&pm_mutex);
 134
 135         swsusp_free();
 136         free_basic_memory_bitmaps();
 137         data = filp->private_data;
 138         free_all_swap_pages(data->swap);
 139         if (data->frozen)
 140                 thaw_processes();
 141         pm_notifier_call_chain(data->mode == O_WRONLY ?
 142                         PM_POST_HIBERNATION : PM_POST_RESTORE);
 143         atomic_inc(&snapshot_device_available);
 144
 145         mutex_unlock(&pm_mutex);
 146
 147         return 0;
 148 }
 149
 150 static ssize_t snapshot_read(struct file *filp, char __user *buf,
 151                              size_t count, loff_t *offp)
 152 {
 153         struct snapshot_data *data;
 154         ssize_t res;
 155
 156         mutex_lock(&pm_mutex);
 157
 158         data = filp->private_data;
 159         if (!data->ready) {
 160                 res = -ENODATA;
 161                 goto Unlock;
 162         }
 163         res = snapshot_read_next(&data->handle, count);
 164         if (res > 0) {
 165                 if (copy_to_user(buf, data_of(data->handle), res))
 166                         res = -EFAULT;
 167                 else
 168                         *offp = data->handle.offset;
 169         }
 170
 171  Unlock:
 172         mutex_unlock(&pm_mutex);
 173
 174         return res;
 175 }
 176
 177 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
 178                               size_t count, loff_t *offp)
 179 {
 180         struct snapshot_data *data;
 181         ssize_t res;
 182
 183         mutex_lock(&pm_mutex);
 184
 185         data = filp->private_data;
 186         res = snapshot_write_next(&data->handle, count);
 187         if (res > 0) {
 188                 if (copy_from_user(data_of(data->handle), buf, res))
 189                         res = -EFAULT;
 190                 else
 191                         *offp = data->handle.offset;
 192         }
 193
 194         mutex_unlock(&pm_mutex);
 195
 196         return res;
 197 }
 198
 199 static long snapshot_ioctl(struct file *filp, unsigned int cmd,
 200                                                         unsigned long arg)
 201 {
 202         int error = 0;
 203         struct snapshot_data *data;
 204         loff_t size;
 205         sector_t offset;
 206
 207         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
 208                 return -ENOTTY;
 209         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
 210                 return -ENOTTY;
 211         if (!capable(CAP_SYS_ADMIN))
 212                 return -EPERM;
 213
 214         if (!mutex_trylock(&pm_mutex))
 215                 return -EBUSY;
 216
 217         data = filp->private_data;
 218
 219         switch (cmd) {
 220
 221         case SNAPSHOT_FREEZE:
 222                 if (data->frozen)
 223                         break;
 224
 225                 printk("Syncing filesystems ... ");
 226                 sys_sync();
 227                 printk("done.\n");
 228
 229                 error = usermodehelper_disable();
 230                 if (error)
 231                         break;
 232
 233                 error = freeze_processes();
 234                 if (error) {
 235                         thaw_processes();
 236                         usermodehelper_enable();
 237                 }
 238                 if (!error)
 239                         data->frozen = 1;
 240                 break;
 241
 242         case SNAPSHOT_UNFREEZE:
 243                 if (!data->frozen || data->ready)
 244                         break;
 245                 thaw_processes();
 246                 usermodehelper_enable();
 247                 data->frozen = 0;
 248                 break;
 249
 250         case SNAPSHOT_CREATE_IMAGE:
 251         case SNAPSHOT_ATOMIC_SNAPSHOT:
 252                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
 253                         error = -EPERM;
 254                         break;
 255                 }
 256                 error = hibernation_snapshot(data->platform_support);
 257                 if (!error)
 258                         error = put_user(in_suspend, (int __user *)arg);
 259                 if (!error)
 260                         data->ready = 1;
 261                 break;
 262
 263         case SNAPSHOT_ATOMIC_RESTORE:
 264                 snapshot_write_finalize(&data->handle);
 265                 if (data->mode != O_WRONLY || !data->frozen ||
 266                     !snapshot_image_loaded(&data->handle)) {
 267                         error = -EPERM;
 268                         break;
 269                 }
 270                 error = hibernation_restore(data->platform_support);
 271                 break;
 272
 273         case SNAPSHOT_FREE:
 274                 swsusp_free();
 275                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
 276                 data->ready = 0;
 277                 break;
 278
 279         case SNAPSHOT_PREF_IMAGE_SIZE:
 280         case SNAPSHOT_SET_IMAGE_SIZE:
 281                 image_size = arg;
 282                 break;
 283
 284         case SNAPSHOT_GET_IMAGE_SIZE:
 285                 if (!data->ready) {
 286                         error = -ENODATA;
 287                         break;
 288                 }
 289                 size = snapshot_get_image_size();
 290                 size <<= PAGE_SHIFT;
 291                 error = put_user(size, (loff_t __user *)arg);
 292                 break;
 293
 294         case SNAPSHOT_AVAIL_SWAP_SIZE:
 295         case SNAPSHOT_AVAIL_SWAP:
 296                 size = count_swap_pages(data->swap, 1);
 297                 size <<= PAGE_SHIFT;
 298                 error = put_user(size, (loff_t __user *)arg);
 299                 break;
 300
 301         case SNAPSHOT_ALLOC_SWAP_PAGE:
 302         case SNAPSHOT_GET_SWAP_PAGE:
 303                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 304                         error = -ENODEV;
 305                         break;
 306                 }
 307                 offset = alloc_swapdev_block(data->swap);
 308                 if (offset) {
 309                         offset <<= PAGE_SHIFT;
 310                         error = put_user(offset, (loff_t __user *)arg);
 311                 } else {
 312                         error = -ENOSPC;
 313                 }
 314                 break;
 315
 316         case SNAPSHOT_FREE_SWAP_PAGES:
 317                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 318                         error = -ENODEV;
 319                         break;
 320                 }
 321                 free_all_swap_pages(data->swap);
 322                 break;
 323
 324         case SNAPSHOT_SET_SWAP_FILE: /* This ioctl is deprecated */
 325                 if (!swsusp_swap_in_use()) {
 326                         /*
 327                          * User space encodes device types as two-byte values,
 328                          * so we need to recode them
 329                          */
 330                         if (old_decode_dev(arg)) {
 331                                 data->swap = swap_type_of(old_decode_dev(arg),
 332                                                         0, NULL);
 333                                 if (data->swap < 0)
 334                                         error = -ENODEV;
 335                         } else {
 336                                 data->swap = -1;
 337                                 error = -EINVAL;
 338                         }
 339                 } else {
 340                         error = -EPERM;
 341                 }
 342                 break;
 343
 344         case SNAPSHOT_S2RAM:
 345                 if (!data->frozen) {
 346                         error = -EPERM;
 347                         break;
 348                 }
 349                 /*
 350                  * Tasks are frozen and the notifiers have been called with
 351                  * PM_HIBERNATION_PREPARE
 352                  */
 353                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 354                 break;
 355
 356         case SNAPSHOT_PLATFORM_SUPPORT:
 357                 data->platform_support = !!arg;
 358                 break;
 359
 360         case SNAPSHOT_POWER_OFF:
 361                 if (data->platform_support)
 362                         error = hibernation_platform_enter();
 363                 break;
 364
 365         case SNAPSHOT_PMOPS: /* This ioctl is deprecated */
 366                 error = -EINVAL;
 367
 368                 switch (arg) {
 369
 370                 case PMOPS_PREPARE:
 371                         data->platform_support = 1;
 372                         error = 0;
 373                         break;
 374
 375                 case PMOPS_ENTER:
 376                         if (data->platform_support)
 377                                 error = hibernation_platform_enter();
 378                         break;
 379
 380                 case PMOPS_FINISH:
 381                         if (data->platform_support)
 382                                 error = 0;
 383                         break;
 384
 385                 default:
 386                         printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
 387
 388                 }
 389                 break;
 390
 391         case SNAPSHOT_SET_SWAP_AREA:
 392                 if (swsusp_swap_in_use()) {
 393                         error = -EPERM;
 394                 } else {
 395                         struct resume_swap_area swap_area;
 396                         dev_t swdev;
 397
 398                         error = copy_from_user(&swap_area, (void __user *)arg,
 399                                         sizeof(struct resume_swap_area));
 400                         if (error) {
 401                                 error = -EFAULT;
 402                                 break;
 403                         }
 404
 405                         /*
 406                          * User space encodes device types as two-byte values,
 407                          * so we need to recode them
 408                          */
 409                         swdev = old_decode_dev(swap_area.dev);
 410                         if (swdev) {
 411                                 offset = swap_area.offset;
 412                                 data->swap = swap_type_of(swdev, offset, NULL);
 413                                 if (data->swap < 0)
 414                                         error = -ENODEV;
 415                         } else {
 416                                 data->swap = -1;
 417                                 error = -EINVAL;
 418                         }
 419                 }
 420                 break;
 421
 422         default:
 423                 error = -ENOTTY;
 424
 425         }
 426
 427         mutex_unlock(&pm_mutex);
 428
 429         return error;
 430 }
 431
 432 static const struct file_operations snapshot_fops = {
 433         .open = snapshot_open,
 434         .release = snapshot_release,
 435         .read = snapshot_read,
 436         .write = snapshot_write,
 437         .llseek = no_llseek,
 438         .unlocked_ioctl = snapshot_ioctl,
 439 };
 440
 441 static struct miscdevice snapshot_device = {
 442         .minor = SNAPSHOT_MINOR,
 443         .name = "snapshot",
 444         .fops = &snapshot_fops,
 445 };
 446
 447 static int __init snapshot_device_init(void)
 448 {
 449         return misc_register(&snapshot_device);
 450 };
 451
 452 device_initcall(snapshot_device_init);