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         if (!atomic_add_unless(&snapshot_device_available, -1, 0))
  74                 return -EBUSY;
  75
  76         if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
  77                 atomic_inc(&snapshot_device_available);
  78                 return -ENOSYS;
  79         }
  80         if(create_basic_memory_bitmaps()) {
  81                 atomic_inc(&snapshot_device_available);
  82                 return -ENOMEM;
  83         }
  84         nonseekable_open(inode, filp);
  85         data = &snapshot_state;
  86         filp->private_data = data;
  87         memset(&data->handle, 0, sizeof(struct snapshot_handle));
  88         if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
  89                 data->swap = swsusp_resume_device ?
  90                         swap_type_of(swsusp_resume_device, 0, NULL) : -1;
  91                 data->mode = O_RDONLY;
  92                 error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
  93                 if (error)
  94                         pm_notifier_call_chain(PM_POST_RESTORE);
  95         } else {
  96                 data->swap = -1;
  97                 data->mode = O_WRONLY;
  98                 error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
  99                 if (error)
 100                         pm_notifier_call_chain(PM_POST_HIBERNATION);
 101         }
 102         if (error) {
 103                 atomic_inc(&snapshot_device_available);
 104                 return error;
 105         }
 106         data->frozen = 0;
 107         data->ready = 0;
 108         data->platform_support = 0;
 109
 110         return 0;
 111 }
 112
 113 static int snapshot_release(struct inode *inode, struct file *filp)
 114 {
 115         struct snapshot_data *data;
 116
 117         swsusp_free();
 118         free_basic_memory_bitmaps();
 119         data = filp->private_data;
 120         free_all_swap_pages(data->swap);
 121         if (data->frozen) {
 122                 mutex_lock(&pm_mutex);
 123                 thaw_processes();
 124                 mutex_unlock(&pm_mutex);
 125         }
 126         pm_notifier_call_chain(data->mode == O_WRONLY ?
 127                         PM_POST_HIBERNATION : PM_POST_RESTORE);
 128         atomic_inc(&snapshot_device_available);
 129         return 0;
 130 }
 131
 132 static ssize_t snapshot_read(struct file *filp, char __user *buf,
 133                              size_t count, loff_t *offp)
 134 {
 135         struct snapshot_data *data;
 136         ssize_t res;
 137
 138         data = filp->private_data;
 139         if (!data->ready)
 140                 return -ENODATA;
 141         res = snapshot_read_next(&data->handle, count);
 142         if (res > 0) {
 143                 if (copy_to_user(buf, data_of(data->handle), res))
 144                         res = -EFAULT;
 145                 else
 146                         *offp = data->handle.offset;
 147         }
 148         return res;
 149 }
 150
 151 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
 152                               size_t count, loff_t *offp)
 153 {
 154         struct snapshot_data *data;
 155         ssize_t res;
 156
 157         data = filp->private_data;
 158         res = snapshot_write_next(&data->handle, count);
 159         if (res > 0) {
 160                 if (copy_from_user(data_of(data->handle), buf, res))
 161                         res = -EFAULT;
 162                 else
 163                         *offp = data->handle.offset;
 164         }
 165         return res;
 166 }
 167
 168 static long snapshot_ioctl(struct file *filp, unsigned int cmd,
 169                                                         unsigned long arg)
 170 {
 171         int error = 0;
 172         struct snapshot_data *data;
 173         loff_t size;
 174         sector_t offset;
 175
 176         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
 177                 return -ENOTTY;
 178         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
 179                 return -ENOTTY;
 180         if (!capable(CAP_SYS_ADMIN))
 181                 return -EPERM;
 182
 183         data = filp->private_data;
 184
 185         lock_kernel();
 186
 187         switch (cmd) {
 188
 189         case SNAPSHOT_FREEZE:
 190                 if (data->frozen)
 191                         break;
 192                 mutex_lock(&pm_mutex);
 193                 printk("Syncing filesystems ... ");
 194                 sys_sync();
 195                 printk("done.\n");
 196
 197                 error = freeze_processes();
 198                 if (error)
 199                         thaw_processes();
 200                 mutex_unlock(&pm_mutex);
 201                 if (!error)
 202                         data->frozen = 1;
 203                 break;
 204
 205         case SNAPSHOT_UNFREEZE:
 206                 if (!data->frozen || data->ready)
 207                         break;
 208                 mutex_lock(&pm_mutex);
 209                 thaw_processes();
 210                 mutex_unlock(&pm_mutex);
 211                 data->frozen = 0;
 212                 break;
 213
 214         case SNAPSHOT_CREATE_IMAGE:
 215         case SNAPSHOT_ATOMIC_SNAPSHOT:
 216                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
 217                         error = -EPERM;
 218                         break;
 219                 }
 220                 error = hibernation_snapshot(data->platform_support);
 221                 if (!error)
 222                         error = put_user(in_suspend, (int __user *)arg);
 223                 if (!error)
 224                         data->ready = 1;
 225                 break;
 226
 227         case SNAPSHOT_ATOMIC_RESTORE:
 228                 snapshot_write_finalize(&data->handle);
 229                 if (data->mode != O_WRONLY || !data->frozen ||
 230                     !snapshot_image_loaded(&data->handle)) {
 231                         error = -EPERM;
 232                         break;
 233                 }
 234                 error = hibernation_restore(data->platform_support);
 235                 break;
 236
 237         case SNAPSHOT_FREE:
 238                 swsusp_free();
 239                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
 240                 data->ready = 0;
 241                 break;
 242
 243         case SNAPSHOT_PREF_IMAGE_SIZE:
 244         case SNAPSHOT_SET_IMAGE_SIZE:
 245                 image_size = arg;
 246                 break;
 247
 248         case SNAPSHOT_GET_IMAGE_SIZE:
 249                 if (!data->ready) {
 250                         error = -ENODATA;
 251                         break;
 252                 }
 253                 size = snapshot_get_image_size();
 254                 size <<= PAGE_SHIFT;
 255                 error = put_user(size, (loff_t __user *)arg);
 256                 break;
 257
 258         case SNAPSHOT_AVAIL_SWAP_SIZE:
 259         case SNAPSHOT_AVAIL_SWAP:
 260                 size = count_swap_pages(data->swap, 1);
 261                 size <<= PAGE_SHIFT;
 262                 error = put_user(size, (loff_t __user *)arg);
 263                 break;
 264
 265         case SNAPSHOT_ALLOC_SWAP_PAGE:
 266         case SNAPSHOT_GET_SWAP_PAGE:
 267                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 268                         error = -ENODEV;
 269                         break;
 270                 }
 271                 offset = alloc_swapdev_block(data->swap);
 272                 if (offset) {
 273                         offset <<= PAGE_SHIFT;
 274                         error = put_user(offset, (loff_t __user *)arg);
 275                 } else {
 276                         error = -ENOSPC;
 277                 }
 278                 break;
 279
 280         case SNAPSHOT_FREE_SWAP_PAGES:
 281                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 282                         error = -ENODEV;
 283                         break;
 284                 }
 285                 free_all_swap_pages(data->swap);
 286                 break;
 287
 288         case SNAPSHOT_SET_SWAP_FILE: /* This ioctl is deprecated */
 289                 if (!swsusp_swap_in_use()) {
 290                         /*
 291                          * User space encodes device types as two-byte values,
 292                          * so we need to recode them
 293                          */
 294                         if (old_decode_dev(arg)) {
 295                                 data->swap = swap_type_of(old_decode_dev(arg),
 296                                                         0, NULL);
 297                                 if (data->swap < 0)
 298                                         error = -ENODEV;
 299                         } else {
 300                                 data->swap = -1;
 301                                 error = -EINVAL;
 302                         }
 303                 } else {
 304                         error = -EPERM;
 305                 }
 306                 break;
 307
 308         case SNAPSHOT_S2RAM:
 309                 if (!data->frozen) {
 310                         error = -EPERM;
 311                         break;
 312                 }
 313                 if (!mutex_trylock(&pm_mutex)) {
 314                         error = -EBUSY;
 315                         break;
 316                 }
 317                 /*
 318                  * Tasks are frozen and the notifiers have been called with
 319                  * PM_HIBERNATION_PREPARE
 320                  */
 321                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 322                 mutex_unlock(&pm_mutex);
 323                 break;
 324
 325         case SNAPSHOT_PLATFORM_SUPPORT:
 326                 data->platform_support = !!arg;
 327                 break;
 328
 329         case SNAPSHOT_POWER_OFF:
 330                 if (data->platform_support)
 331                         error = hibernation_platform_enter();
 332                 break;
 333
 334         case SNAPSHOT_PMOPS: /* This ioctl is deprecated */
 335                 error = -EINVAL;
 336
 337                 switch (arg) {
 338
 339                 case PMOPS_PREPARE:
 340                         data->platform_support = 1;
 341                         error = 0;
 342                         break;
 343
 344                 case PMOPS_ENTER:
 345                         if (data->platform_support)
 346                                 error = hibernation_platform_enter();
 347                         break;
 348
 349                 case PMOPS_FINISH:
 350                         if (data->platform_support)
 351                                 error = 0;
 352                         break;
 353
 354                 default:
 355                         printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
 356
 357                 }
 358                 break;
 359
 360         case SNAPSHOT_SET_SWAP_AREA:
 361                 if (swsusp_swap_in_use()) {
 362                         error = -EPERM;
 363                 } else {
 364                         struct resume_swap_area swap_area;
 365                         dev_t swdev;
 366
 367                         error = copy_from_user(&swap_area, (void __user *)arg,
 368                                         sizeof(struct resume_swap_area));
 369                         if (error) {
 370                                 error = -EFAULT;
 371                                 break;
 372                         }
 373
 374                         /*
 375                          * User space encodes device types as two-byte values,
 376                          * so we need to recode them
 377                          */
 378                         swdev = old_decode_dev(swap_area.dev);
 379                         if (swdev) {
 380                                 offset = swap_area.offset;
 381                                 data->swap = swap_type_of(swdev, offset, NULL);
 382                                 if (data->swap < 0)
 383                                         error = -ENODEV;
 384                         } else {
 385                                 data->swap = -1;
 386                                 error = -EINVAL;
 387                         }
 388                 }
 389                 break;
 390
 391         default:
 392                 error = -ENOTTY;
 393
 394         }
 395         unlock_kernel();
 396         return error;
 397 }
 398
 399 static const struct file_operations snapshot_fops = {
 400         .open = snapshot_open,
 401         .release = snapshot_release,
 402         .read = snapshot_read,
 403         .write = snapshot_write,
 404         .llseek = no_llseek,
 405         .unlocked_ioctl = snapshot_ioctl,
 406 };
 407
 408 static struct miscdevice snapshot_device = {
 409         .minor = SNAPSHOT_MINOR,
 410         .name = "snapshot",
 411         .fops = &snapshot_fops,
 412 };
 413
 414 static int __init snapshot_device_init(void)
 415 {
 416         return misc_register(&snapshot_device);
 417 };
 418
 419 device_initcall(snapshot_device_init);