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                 printk("Syncing filesystems ... ");
 216                 sys_sync();
 217                 printk("done.\n");
 218
 219                 error = freeze_processes();
 220                 if (error)
 221                         thaw_processes();
 222                 if (!error)
 223                         data->frozen = 1;
 224                 break;
 225
 226         case SNAPSHOT_UNFREEZE:
 227                 if (!data->frozen || data->ready)
 228                         break;
 229                 thaw_processes();
 230                 data->frozen = 0;
 231                 break;
 232
 233         case SNAPSHOT_CREATE_IMAGE:
 234         case SNAPSHOT_ATOMIC_SNAPSHOT:
 235                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
 236                         error = -EPERM;
 237                         break;
 238                 }
 239                 error = hibernation_snapshot(data->platform_support);
 240                 if (!error)
 241                         error = put_user(in_suspend, (int __user *)arg);
 242                 if (!error)
 243                         data->ready = 1;
 244                 break;
 245
 246         case SNAPSHOT_ATOMIC_RESTORE:
 247                 snapshot_write_finalize(&data->handle);
 248                 if (data->mode != O_WRONLY || !data->frozen ||
 249                     !snapshot_image_loaded(&data->handle)) {
 250                         error = -EPERM;
 251                         break;
 252                 }
 253                 error = hibernation_restore(data->platform_support);
 254                 break;
 255
 256         case SNAPSHOT_FREE:
 257                 swsusp_free();
 258                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
 259                 data->ready = 0;
 260                 break;
 261
 262         case SNAPSHOT_PREF_IMAGE_SIZE:
 263         case SNAPSHOT_SET_IMAGE_SIZE:
 264                 image_size = arg;
 265                 break;
 266
 267         case SNAPSHOT_GET_IMAGE_SIZE:
 268                 if (!data->ready) {
 269                         error = -ENODATA;
 270                         break;
 271                 }
 272                 size = snapshot_get_image_size();
 273                 size <<= PAGE_SHIFT;
 274                 error = put_user(size, (loff_t __user *)arg);
 275                 break;
 276
 277         case SNAPSHOT_AVAIL_SWAP_SIZE:
 278         case SNAPSHOT_AVAIL_SWAP:
 279                 size = count_swap_pages(data->swap, 1);
 280                 size <<= PAGE_SHIFT;
 281                 error = put_user(size, (loff_t __user *)arg);
 282                 break;
 283
 284         case SNAPSHOT_ALLOC_SWAP_PAGE:
 285         case SNAPSHOT_GET_SWAP_PAGE:
 286                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 287                         error = -ENODEV;
 288                         break;
 289                 }
 290                 offset = alloc_swapdev_block(data->swap);
 291                 if (offset) {
 292                         offset <<= PAGE_SHIFT;
 293                         error = put_user(offset, (loff_t __user *)arg);
 294                 } else {
 295                         error = -ENOSPC;
 296                 }
 297                 break;
 298
 299         case SNAPSHOT_FREE_SWAP_PAGES:
 300                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 301                         error = -ENODEV;
 302                         break;
 303                 }
 304                 free_all_swap_pages(data->swap);
 305                 break;
 306
 307         case SNAPSHOT_SET_SWAP_FILE: /* This ioctl is deprecated */
 308                 if (!swsusp_swap_in_use()) {
 309                         /*
 310                          * User space encodes device types as two-byte values,
 311                          * so we need to recode them
 312                          */
 313                         if (old_decode_dev(arg)) {
 314                                 data->swap = swap_type_of(old_decode_dev(arg),
 315                                                         0, NULL);
 316                                 if (data->swap < 0)
 317                                         error = -ENODEV;
 318                         } else {
 319                                 data->swap = -1;
 320                                 error = -EINVAL;
 321                         }
 322                 } else {
 323                         error = -EPERM;
 324                 }
 325                 break;
 326
 327         case SNAPSHOT_S2RAM:
 328                 if (!data->frozen) {
 329                         error = -EPERM;
 330                         break;
 331                 }
 332                 /*
 333                  * Tasks are frozen and the notifiers have been called with
 334                  * PM_HIBERNATION_PREPARE
 335                  */
 336                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 337                 break;
 338
 339         case SNAPSHOT_PLATFORM_SUPPORT:
 340                 data->platform_support = !!arg;
 341                 break;
 342
 343         case SNAPSHOT_POWER_OFF:
 344                 if (data->platform_support)
 345                         error = hibernation_platform_enter();
 346                 break;
 347
 348         case SNAPSHOT_PMOPS: /* This ioctl is deprecated */
 349                 error = -EINVAL;
 350
 351                 switch (arg) {
 352
 353                 case PMOPS_PREPARE:
 354                         data->platform_support = 1;
 355                         error = 0;
 356                         break;
 357
 358                 case PMOPS_ENTER:
 359                         if (data->platform_support)
 360                                 error = hibernation_platform_enter();
 361                         break;
 362
 363                 case PMOPS_FINISH:
 364                         if (data->platform_support)
 365                                 error = 0;
 366                         break;
 367
 368                 default:
 369                         printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
 370
 371                 }
 372                 break;
 373
 374         case SNAPSHOT_SET_SWAP_AREA:
 375                 if (swsusp_swap_in_use()) {
 376                         error = -EPERM;
 377                 } else {
 378                         struct resume_swap_area swap_area;
 379                         dev_t swdev;
 380
 381                         error = copy_from_user(&swap_area, (void __user *)arg,
 382                                         sizeof(struct resume_swap_area));
 383                         if (error) {
 384                                 error = -EFAULT;
 385                                 break;
 386                         }
 387
 388                         /*
 389                          * User space encodes device types as two-byte values,
 390                          * so we need to recode them
 391                          */
 392                         swdev = old_decode_dev(swap_area.dev);
 393                         if (swdev) {
 394                                 offset = swap_area.offset;
 395                                 data->swap = swap_type_of(swdev, offset, NULL);
 396                                 if (data->swap < 0)
 397                                         error = -ENODEV;
 398                         } else {
 399                                 data->swap = -1;
 400                                 error = -EINVAL;
 401                         }
 402                 }
 403                 break;
 404
 405         default:
 406                 error = -ENOTTY;
 407
 408         }
 409
 410         mutex_unlock(&pm_mutex);
 411
 412         return error;
 413 }
 414
 415 static const struct file_operations snapshot_fops = {
 416         .open = snapshot_open,
 417         .release = snapshot_release,
 418         .read = snapshot_read,
 419         .write = snapshot_write,
 420         .llseek = no_llseek,
 421         .unlocked_ioctl = snapshot_ioctl,
 422 };
 423
 424 static struct miscdevice snapshot_device = {
 425         .minor = SNAPSHOT_MINOR,
 426         .name = "snapshot",
 427         .fops = &snapshot_fops,
 428 };
 429
 430 static int __init snapshot_device_init(void)
 431 {
 432         return misc_register(&snapshot_device);
 433 };
 434
 435 device_initcall(snapshot_device_init);