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
  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                 data->swap = swsusp_resume_device ?
  96                         swap_type_of(swsusp_resume_device, 0, NULL) : -1;
  97                 data->mode = O_RDONLY;
  98                 error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
  99                 if (error)
 100                         pm_notifier_call_chain(PM_POST_RESTORE);
 101         } else {
 102                 data->swap = -1;
 103                 data->mode = O_WRONLY;
 104                 error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
 105                 if (error)
 106                         pm_notifier_call_chain(PM_POST_HIBERNATION);
 107         }
 108         if (error)
 109                 atomic_inc(&snapshot_device_available);
 110         data->frozen = 0;
 111         data->ready = 0;
 112         data->platform_support = 0;
 113
 114  Unlock:
 115         mutex_unlock(&pm_mutex);
 116
 117         return error;
 118 }
 119
 120 static int snapshot_release(struct inode *inode, struct file *filp)
 121 {
 122         struct snapshot_data *data;
 123
 124         mutex_lock(&pm_mutex);
 125
 126         swsusp_free();
 127         free_basic_memory_bitmaps();
 128         data = filp->private_data;
 129         free_all_swap_pages(data->swap);
 130         if (data->frozen)
 131                 thaw_processes();
 132         pm_notifier_call_chain(data->mode == O_WRONLY ?
 133                         PM_POST_HIBERNATION : PM_POST_RESTORE);
 134         atomic_inc(&snapshot_device_available);
 135
 136         mutex_unlock(&pm_mutex);
 137
 138         return 0;
 139 }
 140
 141 static ssize_t snapshot_read(struct file *filp, char __user *buf,
 142                              size_t count, loff_t *offp)
 143 {
 144         struct snapshot_data *data;
 145         ssize_t res;
 146
 147         mutex_lock(&pm_mutex);
 148
 149         data = filp->private_data;
 150         if (!data->ready) {
 151                 res = -ENODATA;
 152                 goto Unlock;
 153         }
 154         res = snapshot_read_next(&data->handle, count);
 155         if (res > 0) {
 156                 if (copy_to_user(buf, data_of(data->handle), res))
 157                         res = -EFAULT;
 158                 else
 159                         *offp = data->handle.offset;
 160         }
 161
 162  Unlock:
 163         mutex_unlock(&pm_mutex);
 164
 165         return res;
 166 }
 167
 168 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
 169                               size_t count, loff_t *offp)
 170 {
 171         struct snapshot_data *data;
 172         ssize_t res;
 173
 174         mutex_lock(&pm_mutex);
 175
 176         data = filp->private_data;
 177         res = snapshot_write_next(&data->handle, count);
 178         if (res > 0) {
 179                 if (copy_from_user(data_of(data->handle), buf, res))
 180                         res = -EFAULT;
 181                 else
 182                         *offp = data->handle.offset;
 183         }
 184
 185         mutex_unlock(&pm_mutex);
 186
 187         return res;
 188 }
 189
 190 static long snapshot_ioctl(struct file *filp, unsigned int cmd,
 191                                                         unsigned long arg)
 192 {
 193         int error = 0;
 194         struct snapshot_data *data;
 195         loff_t size;
 196         sector_t offset;
 197
 198         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
 199                 return -ENOTTY;
 200         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
 201                 return -ENOTTY;
 202         if (!capable(CAP_SYS_ADMIN))
 203                 return -EPERM;
 204
 205         if (!mutex_trylock(&pm_mutex))
 206                 return -EBUSY;
 207
 208         data = filp->private_data;
 209
 210         switch (cmd) {
 211
 212         case SNAPSHOT_FREEZE:
 213                 if (data->frozen)
 214                         break;
 215
 216                 printk("Syncing filesystems ... ");
 217                 sys_sync();
 218                 printk("done.\n");
 219
 220                 error = usermodehelper_disable();
 221                 if (error)
 222                         break;
 223
 224                 error = freeze_processes();
 225                 if (error) {
 226                         thaw_processes();
 227                         usermodehelper_enable();
 228                 }
 229                 if (!error)
 230                         data->frozen = 1;
 231                 break;
 232
 233         case SNAPSHOT_UNFREEZE:
 234                 if (!data->frozen || data->ready)
 235                         break;
 236                 thaw_processes();
 237                 usermodehelper_enable();
 238                 data->frozen = 0;
 239                 break;
 240
 241         case SNAPSHOT_CREATE_IMAGE:
 242         case SNAPSHOT_ATOMIC_SNAPSHOT:
 243                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
 244                         error = -EPERM;
 245                         break;
 246                 }
 247                 error = hibernation_snapshot(data->platform_support);
 248                 if (!error)
 249                         error = put_user(in_suspend, (int __user *)arg);
 250                 if (!error)
 251                         data->ready = 1;
 252                 break;
 253
 254         case SNAPSHOT_ATOMIC_RESTORE:
 255                 snapshot_write_finalize(&data->handle);
 256                 if (data->mode != O_WRONLY || !data->frozen ||
 257                     !snapshot_image_loaded(&data->handle)) {
 258                         error = -EPERM;
 259                         break;
 260                 }
 261                 error = hibernation_restore(data->platform_support);
 262                 break;
 263
 264         case SNAPSHOT_FREE:
 265                 swsusp_free();
 266                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
 267                 data->ready = 0;
 268                 break;
 269
 270         case SNAPSHOT_PREF_IMAGE_SIZE:
 271         case SNAPSHOT_SET_IMAGE_SIZE:
 272                 image_size = arg;
 273                 break;
 274
 275         case SNAPSHOT_GET_IMAGE_SIZE:
 276                 if (!data->ready) {
 277                         error = -ENODATA;
 278                         break;
 279                 }
 280                 size = snapshot_get_image_size();
 281                 size <<= PAGE_SHIFT;
 282                 error = put_user(size, (loff_t __user *)arg);
 283                 break;
 284
 285         case SNAPSHOT_AVAIL_SWAP_SIZE:
 286         case SNAPSHOT_AVAIL_SWAP:
 287                 size = count_swap_pages(data->swap, 1);
 288                 size <<= PAGE_SHIFT;
 289                 error = put_user(size, (loff_t __user *)arg);
 290                 break;
 291
 292         case SNAPSHOT_ALLOC_SWAP_PAGE:
 293         case SNAPSHOT_GET_SWAP_PAGE:
 294                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 295                         error = -ENODEV;
 296                         break;
 297                 }
 298                 offset = alloc_swapdev_block(data->swap);
 299                 if (offset) {
 300                         offset <<= PAGE_SHIFT;
 301                         error = put_user(offset, (loff_t __user *)arg);
 302                 } else {
 303                         error = -ENOSPC;
 304                 }
 305                 break;
 306
 307         case SNAPSHOT_FREE_SWAP_PAGES:
 308                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 309                         error = -ENODEV;
 310                         break;
 311                 }
 312                 free_all_swap_pages(data->swap);
 313                 break;
 314
 315         case SNAPSHOT_SET_SWAP_FILE: /* This ioctl is deprecated */
 316                 if (!swsusp_swap_in_use()) {
 317                         /*
 318                          * User space encodes device types as two-byte values,
 319                          * so we need to recode them
 320                          */
 321                         if (old_decode_dev(arg)) {
 322                                 data->swap = swap_type_of(old_decode_dev(arg),
 323                                                         0, NULL);
 324                                 if (data->swap < 0)
 325                                         error = -ENODEV;
 326                         } else {
 327                                 data->swap = -1;
 328                                 error = -EINVAL;
 329                         }
 330                 } else {
 331                         error = -EPERM;
 332                 }
 333                 break;
 334
 335         case SNAPSHOT_S2RAM:
 336                 if (!data->frozen) {
 337                         error = -EPERM;
 338                         break;
 339                 }
 340                 /*
 341                  * Tasks are frozen and the notifiers have been called with
 342                  * PM_HIBERNATION_PREPARE
 343                  */
 344                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 345                 break;
 346
 347         case SNAPSHOT_PLATFORM_SUPPORT:
 348                 data->platform_support = !!arg;
 349                 break;
 350
 351         case SNAPSHOT_POWER_OFF:
 352                 if (data->platform_support)
 353                         error = hibernation_platform_enter();
 354                 break;
 355
 356         case SNAPSHOT_PMOPS: /* This ioctl is deprecated */
 357                 error = -EINVAL;
 358
 359                 switch (arg) {
 360
 361                 case PMOPS_PREPARE:
 362                         data->platform_support = 1;
 363                         error = 0;
 364                         break;
 365
 366                 case PMOPS_ENTER:
 367                         if (data->platform_support)
 368                                 error = hibernation_platform_enter();
 369                         break;
 370
 371                 case PMOPS_FINISH:
 372                         if (data->platform_support)
 373                                 error = 0;
 374                         break;
 375
 376                 default:
 377                         printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
 378
 379                 }
 380                 break;
 381
 382         case SNAPSHOT_SET_SWAP_AREA:
 383                 if (swsusp_swap_in_use()) {
 384                         error = -EPERM;
 385                 } else {
 386                         struct resume_swap_area swap_area;
 387                         dev_t swdev;
 388
 389                         error = copy_from_user(&swap_area, (void __user *)arg,
 390                                         sizeof(struct resume_swap_area));
 391                         if (error) {
 392                                 error = -EFAULT;
 393                                 break;
 394                         }
 395
 396                         /*
 397                          * User space encodes device types as two-byte values,
 398                          * so we need to recode them
 399                          */
 400                         swdev = old_decode_dev(swap_area.dev);
 401                         if (swdev) {
 402                                 offset = swap_area.offset;
 403                                 data->swap = swap_type_of(swdev, offset, NULL);
 404                                 if (data->swap < 0)
 405                                         error = -ENODEV;
 406                         } else {
 407                                 data->swap = -1;
 408                                 error = -EINVAL;
 409                         }
 410                 }
 411                 break;
 412
 413         default:
 414                 error = -ENOTTY;
 415
 416         }
 417
 418         mutex_unlock(&pm_mutex);
 419
 420         return error;
 421 }
 422
 423 static const struct file_operations snapshot_fops = {
 424         .open = snapshot_open,
 425         .release = snapshot_release,
 426         .read = snapshot_read,
 427         .write = snapshot_write,
 428         .llseek = no_llseek,
 429         .unlocked_ioctl = snapshot_ioctl,
 430 };
 431
 432 static struct miscdevice snapshot_device = {
 433         .minor = SNAPSHOT_MINOR,
 434         .name = "snapshot",
 435         .fops = &snapshot_fops,
 436 };
 437
 438 static int __init snapshot_device_init(void)
 439 {
 440         return misc_register(&snapshot_device);
 441 };
 442
 443 device_initcall(snapshot_device_init);