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 #define SNAPSHOT_MINOR  231
  32
  33 static struct snapshot_data {
  34         struct snapshot_handle handle;
  35         int swap;
  36         struct bitmap_page *bitmap;
  37         int mode;
  38         char frozen;
  39         char ready;
  40         char platform_suspend;
  41 } snapshot_state;
  42
  43 static atomic_t device_available = ATOMIC_INIT(1);
  44
  45 static int snapshot_open(struct inode *inode, struct file *filp)
  46 {
  47         struct snapshot_data *data;
  48
  49         if (!atomic_add_unless(&device_available, -1, 0))
  50                 return -EBUSY;
  51
  52         if ((filp->f_flags & O_ACCMODE) == O_RDWR)
  53                 return -ENOSYS;
  54
  55         nonseekable_open(inode, filp);
  56         data = &snapshot_state;
  57         filp->private_data = data;
  58         memset(&data->handle, 0, sizeof(struct snapshot_handle));
  59         if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
  60                 data->swap = swsusp_resume_device ?
  61                         swap_type_of(swsusp_resume_device, 0, NULL) : -1;
  62                 data->mode = O_RDONLY;
  63         } else {
  64                 data->swap = -1;
  65                 data->mode = O_WRONLY;
  66         }
  67         data->bitmap = NULL;
  68         data->frozen = 0;
  69         data->ready = 0;
  70         data->platform_suspend = 0;
  71
  72         return 0;
  73 }
  74
  75 static int snapshot_release(struct inode *inode, struct file *filp)
  76 {
  77         struct snapshot_data *data;
  78
  79         swsusp_free();
  80         data = filp->private_data;
  81         free_all_swap_pages(data->swap, data->bitmap);
  82         free_bitmap(data->bitmap);
  83         if (data->frozen) {
  84                 mutex_lock(&pm_mutex);
  85                 thaw_processes();
  86                 enable_nonboot_cpus();
  87                 mutex_unlock(&pm_mutex);
  88         }
  89         atomic_inc(&device_available);
  90         return 0;
  91 }
  92
  93 static ssize_t snapshot_read(struct file *filp, char __user *buf,
  94                              size_t count, loff_t *offp)
  95 {
  96         struct snapshot_data *data;
  97         ssize_t res;
  98
  99         data = filp->private_data;
 100         res = snapshot_read_next(&data->handle, count);
 101         if (res > 0) {
 102                 if (copy_to_user(buf, data_of(data->handle), res))
 103                         res = -EFAULT;
 104                 else
 105                         *offp = data->handle.offset;
 106         }
 107         return res;
 108 }
 109
 110 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
 111                               size_t count, loff_t *offp)
 112 {
 113         struct snapshot_data *data;
 114         ssize_t res;
 115
 116         data = filp->private_data;
 117         res = snapshot_write_next(&data->handle, count);
 118         if (res > 0) {
 119                 if (copy_from_user(data_of(data->handle), buf, res))
 120                         res = -EFAULT;
 121                 else
 122                         *offp = data->handle.offset;
 123         }
 124         return res;
 125 }
 126
 127 static inline int platform_prepare(void)
 128 {
 129         int error = 0;
 130
 131         if (pm_ops && pm_ops->prepare)
 132                 error = pm_ops->prepare(PM_SUSPEND_DISK);
 133
 134         return error;
 135 }
 136
 137 static inline void platform_finish(void)
 138 {
 139         if (pm_ops && pm_ops->finish)
 140                 pm_ops->finish(PM_SUSPEND_DISK);
 141 }
 142
 143 static inline int snapshot_suspend(int platform_suspend)
 144 {
 145         int error;
 146
 147         mutex_lock(&pm_mutex);
 148         /* Free memory before shutting down devices. */
 149         error = swsusp_shrink_memory();
 150         if (error)
 151                 goto Finish;
 152
 153         if (platform_suspend) {
 154                 error = platform_prepare();
 155                 if (error)
 156                         goto Finish;
 157         }
 158         suspend_console();
 159         error = device_suspend(PMSG_FREEZE);
 160         if (error)
 161                 goto Resume_devices;
 162
 163         error = disable_nonboot_cpus();
 164         if (!error) {
 165                 in_suspend = 1;
 166                 error = swsusp_suspend();
 167         }
 168         enable_nonboot_cpus();
 169  Resume_devices:
 170         if (platform_suspend)
 171                 platform_finish();
 172
 173         device_resume();
 174         resume_console();
 175  Finish:
 176         mutex_unlock(&pm_mutex);
 177         return error;
 178 }
 179
 180 static inline int snapshot_restore(int platform_suspend)
 181 {
 182         int error;
 183
 184         mutex_lock(&pm_mutex);
 185         pm_prepare_console();
 186         if (platform_suspend) {
 187                 error = platform_prepare();
 188                 if (error)
 189                         goto Finish;
 190         }
 191         suspend_console();
 192         error = device_suspend(PMSG_PRETHAW);
 193         if (error)
 194                 goto Resume_devices;
 195
 196         error = disable_nonboot_cpus();
 197         if (!error)
 198                 error = swsusp_resume();
 199
 200         enable_nonboot_cpus();
 201  Resume_devices:
 202         if (platform_suspend)
 203                 platform_finish();
 204
 205         device_resume();
 206         resume_console();
 207  Finish:
 208         pm_restore_console();
 209         mutex_unlock(&pm_mutex);
 210         return error;
 211 }
 212
 213 static int snapshot_ioctl(struct inode *inode, struct file *filp,
 214                           unsigned int cmd, unsigned long arg)
 215 {
 216         int error = 0;
 217         struct snapshot_data *data;
 218         loff_t avail;
 219         sector_t offset;
 220
 221         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
 222                 return -ENOTTY;
 223         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
 224                 return -ENOTTY;
 225         if (!capable(CAP_SYS_ADMIN))
 226                 return -EPERM;
 227
 228         data = filp->private_data;
 229
 230         switch (cmd) {
 231
 232         case SNAPSHOT_FREEZE:
 233                 if (data->frozen)
 234                         break;
 235                 mutex_lock(&pm_mutex);
 236                 if (freeze_processes()) {
 237                         thaw_processes();
 238                         error = -EBUSY;
 239                 }
 240                 mutex_unlock(&pm_mutex);
 241                 if (!error)
 242                         data->frozen = 1;
 243                 break;
 244
 245         case SNAPSHOT_UNFREEZE:
 246                 if (!data->frozen)
 247                         break;
 248                 mutex_lock(&pm_mutex);
 249                 thaw_processes();
 250                 mutex_unlock(&pm_mutex);
 251                 data->frozen = 0;
 252                 break;
 253
 254         case SNAPSHOT_ATOMIC_SNAPSHOT:
 255                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
 256                         error = -EPERM;
 257                         break;
 258                 }
 259                 error = snapshot_suspend(data->platform_suspend);
 260                 if (!error)
 261                         error = put_user(in_suspend, (unsigned int __user *)arg);
 262                 if (!error)
 263                         data->ready = 1;
 264                 break;
 265
 266         case SNAPSHOT_ATOMIC_RESTORE:
 267                 snapshot_write_finalize(&data->handle);
 268                 if (data->mode != O_WRONLY || !data->frozen ||
 269                     !snapshot_image_loaded(&data->handle)) {
 270                         error = -EPERM;
 271                         break;
 272                 }
 273                 error = snapshot_restore(data->platform_suspend);
 274                 break;
 275
 276         case SNAPSHOT_FREE:
 277                 swsusp_free();
 278                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
 279                 data->ready = 0;
 280                 break;
 281
 282         case SNAPSHOT_SET_IMAGE_SIZE:
 283                 image_size = arg;
 284                 break;
 285
 286         case SNAPSHOT_AVAIL_SWAP:
 287                 avail = count_swap_pages(data->swap, 1);
 288                 avail <<= PAGE_SHIFT;
 289                 error = put_user(avail, (loff_t __user *)arg);
 290                 break;
 291
 292         case SNAPSHOT_GET_SWAP_PAGE:
 293                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 294                         error = -ENODEV;
 295                         break;
 296                 }
 297                 if (!data->bitmap) {
 298                         data->bitmap = alloc_bitmap(count_swap_pages(data->swap, 0));
 299                         if (!data->bitmap) {
 300                                 error = -ENOMEM;
 301                                 break;
 302                         }
 303                 }
 304                 offset = alloc_swapdev_block(data->swap, data->bitmap);
 305                 if (offset) {
 306                         offset <<= PAGE_SHIFT;
 307                         error = put_user(offset, (sector_t __user *)arg);
 308                 } else {
 309                         error = -ENOSPC;
 310                 }
 311                 break;
 312
 313         case SNAPSHOT_FREE_SWAP_PAGES:
 314                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 315                         error = -ENODEV;
 316                         break;
 317                 }
 318                 free_all_swap_pages(data->swap, data->bitmap);
 319                 free_bitmap(data->bitmap);
 320                 data->bitmap = NULL;
 321                 break;
 322
 323         case SNAPSHOT_SET_SWAP_FILE:
 324                 if (!data->bitmap) {
 325                         /*
 326                          * User space encodes device types as two-byte values,
 327                          * so we need to recode them
 328                          */
 329                         if (old_decode_dev(arg)) {
 330                                 data->swap = swap_type_of(old_decode_dev(arg),
 331                                                         0, NULL);
 332                                 if (data->swap < 0)
 333                                         error = -ENODEV;
 334                         } else {
 335                                 data->swap = -1;
 336                                 error = -EINVAL;
 337                         }
 338                 } else {
 339                         error = -EPERM;
 340                 }
 341                 break;
 342
 343         case SNAPSHOT_S2RAM:
 344                 if (!pm_ops) {
 345                         error = -ENOSYS;
 346                         break;
 347                 }
 348
 349                 if (!data->frozen) {
 350                         error = -EPERM;
 351                         break;
 352                 }
 353
 354                 if (!mutex_trylock(&pm_mutex)) {
 355                         error = -EBUSY;
 356                         break;
 357                 }
 358
 359                 if (pm_ops->prepare) {
 360                         error = pm_ops->prepare(PM_SUSPEND_MEM);
 361                         if (error)
 362                                 goto OutS3;
 363                 }
 364
 365                 /* Put devices to sleep */
 366                 suspend_console();
 367                 error = device_suspend(PMSG_SUSPEND);
 368                 if (error) {
 369                         printk(KERN_ERR "Failed to suspend some devices.\n");
 370                 } else {
 371                         error = disable_nonboot_cpus();
 372                         if (!error) {
 373                                 /* Enter S3, system is already frozen */
 374                                 suspend_enter(PM_SUSPEND_MEM);
 375                                 enable_nonboot_cpus();
 376                         }
 377                         /* Wake up devices */
 378                         device_resume();
 379                 }
 380                 resume_console();
 381                 if (pm_ops->finish)
 382                         pm_ops->finish(PM_SUSPEND_MEM);
 383
 384  OutS3:
 385                 mutex_unlock(&pm_mutex);
 386                 break;
 387
 388         case SNAPSHOT_PMOPS:
 389                 error = -EINVAL;
 390
 391                 switch (arg) {
 392
 393                 case PMOPS_PREPARE:
 394                         if (pm_ops && pm_ops->enter) {
 395                                 data->platform_suspend = 1;
 396                                 error = 0;
 397                         } else {
 398                                 error = -ENOSYS;
 399                         }
 400                         break;
 401
 402                 case PMOPS_ENTER:
 403                         if (data->platform_suspend) {
 404                                 kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
 405                                 error = pm_ops->enter(PM_SUSPEND_DISK);
 406                                 error = 0;
 407                         }
 408                         break;
 409
 410                 case PMOPS_FINISH:
 411                         if (data->platform_suspend)
 412                                 error = 0;
 413
 414                         break;
 415
 416                 default:
 417                         printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
 418
 419                 }
 420                 break;
 421
 422         case SNAPSHOT_SET_SWAP_AREA:
 423                 if (data->bitmap) {
 424                         error = -EPERM;
 425                 } else {
 426                         struct resume_swap_area swap_area;
 427                         dev_t swdev;
 428
 429                         error = copy_from_user(&swap_area, (void __user *)arg,
 430                                         sizeof(struct resume_swap_area));
 431                         if (error) {
 432                                 error = -EFAULT;
 433                                 break;
 434                         }
 435
 436                         /*
 437                          * User space encodes device types as two-byte values,
 438                          * so we need to recode them
 439                          */
 440                         swdev = old_decode_dev(swap_area.dev);
 441                         if (swdev) {
 442                                 offset = swap_area.offset;
 443                                 data->swap = swap_type_of(swdev, offset, NULL);
 444                                 if (data->swap < 0)
 445                                         error = -ENODEV;
 446                         } else {
 447                                 data->swap = -1;
 448                                 error = -EINVAL;
 449                         }
 450                 }
 451                 break;
 452
 453         default:
 454                 error = -ENOTTY;
 455
 456         }
 457
 458         return error;
 459 }
 460
 461 static const struct file_operations snapshot_fops = {
 462         .open = snapshot_open,
 463         .release = snapshot_release,
 464         .read = snapshot_read,
 465         .write = snapshot_write,
 466         .llseek = no_llseek,
 467         .ioctl = snapshot_ioctl,
 468 };
 469
 470 static struct miscdevice snapshot_device = {
 471         .minor = SNAPSHOT_MINOR,
 472         .name = "snapshot",
 473         .fops = &snapshot_fops,
 474 };
 475
 476 static int __init snapshot_device_init(void)
 477 {
 478         return misc_register(&snapshot_device);
 479 };
 480
 481 device_initcall(snapshot_device_init);