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