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         if (!data->ready)
 103                 return -ENODATA;
 104         res = snapshot_read_next(&data->handle, count);
 105         if (res > 0) {
 106                 if (copy_to_user(buf, data_of(data->handle), res))
 107                         res = -EFAULT;
 108                 else
 109                         *offp = data->handle.offset;
 110         }
 111         return res;
 112 }
 113
 114 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
 115                               size_t count, loff_t *offp)
 116 {
 117         struct snapshot_data *data;
 118         ssize_t res;
 119
 120         data = filp->private_data;
 121         res = snapshot_write_next(&data->handle, count);
 122         if (res > 0) {
 123                 if (copy_from_user(data_of(data->handle), buf, res))
 124                         res = -EFAULT;
 125                 else
 126                         *offp = data->handle.offset;
 127         }
 128         return res;
 129 }
 130
 131 static inline int platform_prepare(void)
 132 {
 133         int error = 0;
 134
 135         if (hibernation_ops)
 136                 error = hibernation_ops->prepare();
 137
 138         return error;
 139 }
 140
 141 static inline void platform_finish(void)
 142 {
 143         if (hibernation_ops)
 144                 hibernation_ops->finish();
 145 }
 146
 147 static inline int snapshot_suspend(int platform_suspend)
 148 {
 149         int error;
 150
 151         mutex_lock(&pm_mutex);
 152         /* Free memory before shutting down devices. */
 153         error = swsusp_shrink_memory();
 154         if (error)
 155                 goto Finish;
 156
 157         if (platform_suspend) {
 158                 error = platform_prepare();
 159                 if (error)
 160                         goto Finish;
 161         }
 162         suspend_console();
 163         error = device_suspend(PMSG_FREEZE);
 164         if (error)
 165                 goto Resume_devices;
 166
 167         error = disable_nonboot_cpus();
 168         if (!error) {
 169                 in_suspend = 1;
 170                 error = swsusp_suspend();
 171         }
 172         enable_nonboot_cpus();
 173  Resume_devices:
 174         if (platform_suspend)
 175                 platform_finish();
 176
 177         device_resume();
 178         resume_console();
 179  Finish:
 180         mutex_unlock(&pm_mutex);
 181         return error;
 182 }
 183
 184 static inline int snapshot_restore(int platform_suspend)
 185 {
 186         int error;
 187
 188         mutex_lock(&pm_mutex);
 189         pm_prepare_console();
 190         if (platform_suspend) {
 191                 error = platform_prepare();
 192                 if (error)
 193                         goto Finish;
 194         }
 195         suspend_console();
 196         error = device_suspend(PMSG_PRETHAW);
 197         if (error)
 198                 goto Resume_devices;
 199
 200         error = disable_nonboot_cpus();
 201         if (!error)
 202                 error = swsusp_resume();
 203
 204         enable_nonboot_cpus();
 205  Resume_devices:
 206         if (platform_suspend)
 207                 platform_finish();
 208
 209         device_resume();
 210         resume_console();
 211  Finish:
 212         pm_restore_console();
 213         mutex_unlock(&pm_mutex);
 214         return error;
 215 }
 216
 217 static int snapshot_ioctl(struct inode *inode, struct file *filp,
 218                           unsigned int cmd, unsigned long arg)
 219 {
 220         int error = 0;
 221         struct snapshot_data *data;
 222         loff_t avail;
 223         sector_t offset;
 224
 225         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
 226                 return -ENOTTY;
 227         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
 228                 return -ENOTTY;
 229         if (!capable(CAP_SYS_ADMIN))
 230                 return -EPERM;
 231
 232         data = filp->private_data;
 233
 234         switch (cmd) {
 235
 236         case SNAPSHOT_FREEZE:
 237                 if (data->frozen)
 238                         break;
 239                 mutex_lock(&pm_mutex);
 240                 if (freeze_processes()) {
 241                         thaw_processes();
 242                         error = -EBUSY;
 243                 }
 244                 mutex_unlock(&pm_mutex);
 245                 if (!error)
 246                         data->frozen = 1;
 247                 break;
 248
 249         case SNAPSHOT_UNFREEZE:
 250                 if (!data->frozen || data->ready)
 251                         break;
 252                 mutex_lock(&pm_mutex);
 253                 thaw_processes();
 254                 mutex_unlock(&pm_mutex);
 255                 data->frozen = 0;
 256                 break;
 257
 258         case SNAPSHOT_ATOMIC_SNAPSHOT:
 259                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
 260                         error = -EPERM;
 261                         break;
 262                 }
 263                 error = snapshot_suspend(data->platform_suspend);
 264                 if (!error)
 265                         error = put_user(in_suspend, (unsigned int __user *)arg);
 266                 if (!error)
 267                         data->ready = 1;
 268                 break;
 269
 270         case SNAPSHOT_ATOMIC_RESTORE:
 271                 snapshot_write_finalize(&data->handle);
 272                 if (data->mode != O_WRONLY || !data->frozen ||
 273                     !snapshot_image_loaded(&data->handle)) {
 274                         error = -EPERM;
 275                         break;
 276                 }
 277                 error = snapshot_restore(data->platform_suspend);
 278                 break;
 279
 280         case SNAPSHOT_FREE:
 281                 swsusp_free();
 282                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
 283                 data->ready = 0;
 284                 break;
 285
 286         case SNAPSHOT_SET_IMAGE_SIZE:
 287                 image_size = arg;
 288                 break;
 289
 290         case SNAPSHOT_AVAIL_SWAP:
 291                 avail = count_swap_pages(data->swap, 1);
 292                 avail <<= PAGE_SHIFT;
 293                 error = put_user(avail, (loff_t __user *)arg);
 294                 break;
 295
 296         case SNAPSHOT_GET_SWAP_PAGE:
 297                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 298                         error = -ENODEV;
 299                         break;
 300                 }
 301                 offset = alloc_swapdev_block(data->swap);
 302                 if (offset) {
 303                         offset <<= PAGE_SHIFT;
 304                         error = put_user(offset, (sector_t __user *)arg);
 305                 } else {
 306                         error = -ENOSPC;
 307                 }
 308                 break;
 309
 310         case SNAPSHOT_FREE_SWAP_PAGES:
 311                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 312                         error = -ENODEV;
 313                         break;
 314                 }
 315                 free_all_swap_pages(data->swap);
 316                 break;
 317
 318         case SNAPSHOT_SET_SWAP_FILE:
 319                 if (!swsusp_swap_in_use()) {
 320                         /*
 321                          * User space encodes device types as two-byte values,
 322                          * so we need to recode them
 323                          */
 324                         if (old_decode_dev(arg)) {
 325                                 data->swap = swap_type_of(old_decode_dev(arg),
 326                                                         0, NULL);
 327                                 if (data->swap < 0)
 328                                         error = -ENODEV;
 329                         } else {
 330                                 data->swap = -1;
 331                                 error = -EINVAL;
 332                         }
 333                 } else {
 334                         error = -EPERM;
 335                 }
 336                 break;
 337
 338         case SNAPSHOT_S2RAM:
 339                 if (!pm_ops) {
 340                         error = -ENOSYS;
 341                         break;
 342                 }
 343
 344                 if (!data->frozen) {
 345                         error = -EPERM;
 346                         break;
 347                 }
 348
 349                 if (!mutex_trylock(&pm_mutex)) {
 350                         error = -EBUSY;
 351                         break;
 352                 }
 353
 354                 if (pm_ops->prepare) {
 355                         error = pm_ops->prepare(PM_SUSPEND_MEM);
 356                         if (error)
 357                                 goto OutS3;
 358                 }
 359
 360                 /* Put devices to sleep */
 361                 suspend_console();
 362                 error = device_suspend(PMSG_SUSPEND);
 363                 if (error) {
 364                         printk(KERN_ERR "Failed to suspend some devices.\n");
 365                 } else {
 366                         error = disable_nonboot_cpus();
 367                         if (!error) {
 368                                 /* Enter S3, system is already frozen */
 369                                 suspend_enter(PM_SUSPEND_MEM);
 370                                 enable_nonboot_cpus();
 371                         }
 372                         /* Wake up devices */
 373                         device_resume();
 374                 }
 375                 resume_console();
 376                 if (pm_ops->finish)
 377                         pm_ops->finish(PM_SUSPEND_MEM);
 378
 379  OutS3:
 380                 mutex_unlock(&pm_mutex);
 381                 break;
 382
 383         case SNAPSHOT_PMOPS:
 384                 error = -EINVAL;
 385
 386                 switch (arg) {
 387
 388                 case PMOPS_PREPARE:
 389                         if (hibernation_ops) {
 390                                 data->platform_suspend = 1;
 391                                 error = 0;
 392                         } else {
 393                                 error = -ENOSYS;
 394                         }
 395                         break;
 396
 397                 case PMOPS_ENTER:
 398                         if (data->platform_suspend) {
 399                                 kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
 400                                 error = hibernation_ops->enter();
 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);