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