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                 atomic_inc(&device_available);
  54                 return -ENOSYS;
  55         }
  56         if(create_basic_memory_bitmaps()) {
  57                 atomic_inc(&device_available);
  58                 return -ENOMEM;
  59         }
  60         nonseekable_open(inode, filp);
  61         data = &snapshot_state;
  62         filp->private_data = data;
  63         memset(&data->handle, 0, sizeof(struct snapshot_handle));
  64         if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
  65                 data->swap = swsusp_resume_device ?
  66                         swap_type_of(swsusp_resume_device, 0, NULL) : -1;
  67                 data->mode = O_RDONLY;
  68         } else {
  69                 data->swap = -1;
  70                 data->mode = O_WRONLY;
  71         }
  72         data->bitmap = NULL;
  73         data->frozen = 0;
  74         data->ready = 0;
  75         data->platform_suspend = 0;
  76
  77         return 0;
  78 }
  79
  80 static int snapshot_release(struct inode *inode, struct file *filp)
  81 {
  82         struct snapshot_data *data;
  83
  84         swsusp_free();
  85         free_basic_memory_bitmaps();
  86         data = filp->private_data;
  87         free_all_swap_pages(data->swap, data->bitmap);
  88         free_bitmap(data->bitmap);
  89         if (data->frozen) {
  90                 mutex_lock(&pm_mutex);
  91                 thaw_processes();
  92                 enable_nonboot_cpus();
  93                 mutex_unlock(&pm_mutex);
  94         }
  95         atomic_inc(&device_available);
  96         return 0;
  97 }
  98
  99 static ssize_t snapshot_read(struct file *filp, char __user *buf,
 100                              size_t count, loff_t *offp)
 101 {
 102         struct snapshot_data *data;
 103         ssize_t res;
 104
 105         data = filp->private_data;
 106         res = snapshot_read_next(&data->handle, count);
 107         if (res > 0) {
 108                 if (copy_to_user(buf, data_of(data->handle), res))
 109                         res = -EFAULT;
 110                 else
 111                         *offp = data->handle.offset;
 112         }
 113         return res;
 114 }
 115
 116 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
 117                               size_t count, loff_t *offp)
 118 {
 119         struct snapshot_data *data;
 120         ssize_t res;
 121
 122         data = filp->private_data;
 123         res = snapshot_write_next(&data->handle, count);
 124         if (res > 0) {
 125                 if (copy_from_user(data_of(data->handle), buf, res))
 126                         res = -EFAULT;
 127                 else
 128                         *offp = data->handle.offset;
 129         }
 130         return res;
 131 }
 132
 133 static inline int platform_prepare(void)
 134 {
 135         int error = 0;
 136
 137         if (pm_ops && pm_ops->prepare)
 138                 error = pm_ops->prepare(PM_SUSPEND_DISK);
 139
 140         return error;
 141 }
 142
 143 static inline void platform_finish(void)
 144 {
 145         if (pm_ops && pm_ops->finish)
 146                 pm_ops->finish(PM_SUSPEND_DISK);
 147 }
 148
 149 static inline int snapshot_suspend(int platform_suspend)
 150 {
 151         int error;
 152
 153         mutex_lock(&pm_mutex);
 154         /* Free memory before shutting down devices. */
 155         error = swsusp_shrink_memory();
 156         if (error)
 157                 goto Finish;
 158
 159         if (platform_suspend) {
 160                 error = platform_prepare();
 161                 if (error)
 162                         goto Finish;
 163         }
 164         suspend_console();
 165         error = device_suspend(PMSG_FREEZE);
 166         if (error)
 167                 goto Resume_devices;
 168
 169         error = disable_nonboot_cpus();
 170         if (!error) {
 171                 in_suspend = 1;
 172                 error = swsusp_suspend();
 173         }
 174         enable_nonboot_cpus();
 175  Resume_devices:
 176         if (platform_suspend)
 177                 platform_finish();
 178
 179         device_resume();
 180         resume_console();
 181  Finish:
 182         mutex_unlock(&pm_mutex);
 183         return error;
 184 }
 185
 186 static inline int snapshot_restore(int platform_suspend)
 187 {
 188         int error;
 189
 190         mutex_lock(&pm_mutex);
 191         pm_prepare_console();
 192         if (platform_suspend) {
 193                 error = platform_prepare();
 194                 if (error)
 195                         goto Finish;
 196         }
 197         suspend_console();
 198         error = device_suspend(PMSG_PRETHAW);
 199         if (error)
 200                 goto Resume_devices;
 201
 202         error = disable_nonboot_cpus();
 203         if (!error)
 204                 error = swsusp_resume();
 205
 206         enable_nonboot_cpus();
 207  Resume_devices:
 208         if (platform_suspend)
 209                 platform_finish();
 210
 211         device_resume();
 212         resume_console();
 213  Finish:
 214         pm_restore_console();
 215         mutex_unlock(&pm_mutex);
 216         return error;
 217 }
 218
 219 static int snapshot_ioctl(struct inode *inode, struct file *filp,
 220                           unsigned int cmd, unsigned long arg)
 221 {
 222         int error = 0;
 223         struct snapshot_data *data;
 224         loff_t avail;
 225         sector_t offset;
 226
 227         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
 228                 return -ENOTTY;
 229         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
 230                 return -ENOTTY;
 231         if (!capable(CAP_SYS_ADMIN))
 232                 return -EPERM;
 233
 234         data = filp->private_data;
 235
 236         switch (cmd) {
 237
 238         case SNAPSHOT_FREEZE:
 239                 if (data->frozen)
 240                         break;
 241                 mutex_lock(&pm_mutex);
 242                 if (freeze_processes()) {
 243                         thaw_processes();
 244                         error = -EBUSY;
 245                 }
 246                 mutex_unlock(&pm_mutex);
 247                 if (!error)
 248                         data->frozen = 1;
 249                 break;
 250
 251         case SNAPSHOT_UNFREEZE:
 252                 if (!data->frozen)
 253                         break;
 254                 mutex_lock(&pm_mutex);
 255                 thaw_processes();
 256                 mutex_unlock(&pm_mutex);
 257                 data->frozen = 0;
 258                 break;
 259
 260         case SNAPSHOT_ATOMIC_SNAPSHOT:
 261                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
 262                         error = -EPERM;
 263                         break;
 264                 }
 265                 error = snapshot_suspend(data->platform_suspend);
 266                 if (!error)
 267                         error = put_user(in_suspend, (unsigned int __user *)arg);
 268                 if (!error)
 269                         data->ready = 1;
 270                 break;
 271
 272         case SNAPSHOT_ATOMIC_RESTORE:
 273                 snapshot_write_finalize(&data->handle);
 274                 if (data->mode != O_WRONLY || !data->frozen ||
 275                     !snapshot_image_loaded(&data->handle)) {
 276                         error = -EPERM;
 277                         break;
 278                 }
 279                 error = snapshot_restore(data->platform_suspend);
 280                 break;
 281
 282         case SNAPSHOT_FREE:
 283                 swsusp_free();
 284                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
 285                 data->ready = 0;
 286                 break;
 287
 288         case SNAPSHOT_SET_IMAGE_SIZE:
 289                 image_size = arg;
 290                 break;
 291
 292         case SNAPSHOT_AVAIL_SWAP:
 293                 avail = count_swap_pages(data->swap, 1);
 294                 avail <<= PAGE_SHIFT;
 295                 error = put_user(avail, (loff_t __user *)arg);
 296                 break;
 297
 298         case SNAPSHOT_GET_SWAP_PAGE:
 299                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 300                         error = -ENODEV;
 301                         break;
 302                 }
 303                 if (!data->bitmap) {
 304                         data->bitmap = alloc_bitmap(count_swap_pages(data->swap, 0));
 305                         if (!data->bitmap) {
 306                                 error = -ENOMEM;
 307                                 break;
 308                         }
 309                 }
 310                 offset = alloc_swapdev_block(data->swap, data->bitmap);
 311                 if (offset) {
 312                         offset <<= PAGE_SHIFT;
 313                         error = put_user(offset, (sector_t __user *)arg);
 314                 } else {
 315                         error = -ENOSPC;
 316                 }
 317                 break;
 318
 319         case SNAPSHOT_FREE_SWAP_PAGES:
 320                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 321                         error = -ENODEV;
 322                         break;
 323                 }
 324                 free_all_swap_pages(data->swap, data->bitmap);
 325                 free_bitmap(data->bitmap);
 326                 data->bitmap = NULL;
 327                 break;
 328
 329         case SNAPSHOT_SET_SWAP_FILE:
 330                 if (!data->bitmap) {
 331                         /*
 332                          * User space encodes device types as two-byte values,
 333                          * so we need to recode them
 334                          */
 335                         if (old_decode_dev(arg)) {
 336                                 data->swap = swap_type_of(old_decode_dev(arg),
 337                                                         0, NULL);
 338                                 if (data->swap < 0)
 339                                         error = -ENODEV;
 340                         } else {
 341                                 data->swap = -1;
 342                                 error = -EINVAL;
 343                         }
 344                 } else {
 345                         error = -EPERM;
 346                 }
 347                 break;
 348
 349         case SNAPSHOT_S2RAM:
 350                 if (!pm_ops) {
 351                         error = -ENOSYS;
 352                         break;
 353                 }
 354
 355                 if (!data->frozen) {
 356                         error = -EPERM;
 357                         break;
 358                 }
 359
 360                 if (!mutex_trylock(&pm_mutex)) {
 361                         error = -EBUSY;
 362                         break;
 363                 }
 364
 365                 if (pm_ops->prepare) {
 366                         error = pm_ops->prepare(PM_SUSPEND_MEM);
 367                         if (error)
 368                                 goto OutS3;
 369                 }
 370
 371                 /* Put devices to sleep */
 372                 suspend_console();
 373                 error = device_suspend(PMSG_SUSPEND);
 374                 if (error) {
 375                         printk(KERN_ERR "Failed to suspend some devices.\n");
 376                 } else {
 377                         error = disable_nonboot_cpus();
 378                         if (!error) {
 379                                 /* Enter S3, system is already frozen */
 380                                 suspend_enter(PM_SUSPEND_MEM);
 381                                 enable_nonboot_cpus();
 382                         }
 383                         /* Wake up devices */
 384                         device_resume();
 385                 }
 386                 resume_console();
 387                 if (pm_ops->finish)
 388                         pm_ops->finish(PM_SUSPEND_MEM);
 389
 390  OutS3:
 391                 mutex_unlock(&pm_mutex);
 392                 break;
 393
 394         case SNAPSHOT_PMOPS:
 395                 error = -EINVAL;
 396
 397                 switch (arg) {
 398
 399                 case PMOPS_PREPARE:
 400                         if (pm_ops && pm_ops->enter) {
 401                                 data->platform_suspend = 1;
 402                                 error = 0;
 403                         } else {
 404                                 error = -ENOSYS;
 405                         }
 406                         break;
 407
 408                 case PMOPS_ENTER:
 409                         if (data->platform_suspend) {
 410                                 kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
 411                                 error = pm_ops->enter(PM_SUSPEND_DISK);
 412                                 error = 0;
 413                         }
 414                         break;
 415
 416                 case PMOPS_FINISH:
 417                         if (data->platform_suspend)
 418                                 error = 0;
 419
 420                         break;
 421
 422                 default:
 423                         printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
 424
 425                 }
 426                 break;
 427
 428         case SNAPSHOT_SET_SWAP_AREA:
 429                 if (data->bitmap) {
 430                         error = -EPERM;
 431                 } else {
 432                         struct resume_swap_area swap_area;
 433                         dev_t swdev;
 434
 435                         error = copy_from_user(&swap_area, (void __user *)arg,
 436                                         sizeof(struct resume_swap_area));
 437                         if (error) {
 438                                 error = -EFAULT;
 439                                 break;
 440                         }
 441
 442                         /*
 443                          * User space encodes device types as two-byte values,
 444                          * so we need to recode them
 445                          */
 446                         swdev = old_decode_dev(swap_area.dev);
 447                         if (swdev) {
 448                                 offset = swap_area.offset;
 449                                 data->swap = swap_type_of(swdev, offset, NULL);
 450                                 if (data->swap < 0)
 451                                         error = -ENODEV;
 452                         } else {
 453                                 data->swap = -1;
 454                                 error = -EINVAL;
 455                         }
 456                 }
 457                 break;
 458
 459         default:
 460                 error = -ENOTTY;
 461
 462         }
 463
 464         return error;
 465 }
 466
 467 static const struct file_operations snapshot_fops = {
 468         .open = snapshot_open,
 469         .release = snapshot_release,
 470         .read = snapshot_read,
 471         .write = snapshot_write,
 472         .llseek = no_llseek,
 473         .ioctl = snapshot_ioctl,
 474 };
 475
 476 static struct miscdevice snapshot_device = {
 477         .minor = SNAPSHOT_MINOR,
 478         .name = "snapshot",
 479         .fops = &snapshot_fops,
 480 };
 481
 482 static int __init snapshot_device_init(void)
 483 {
 484         return misc_register(&snapshot_device);
 485 };
 486
 487 device_initcall(snapshot_device_init);