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