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