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(void)
 185 {
 186         int error;
 187
 188         mutex_lock(&pm_mutex);
 189         pm_prepare_console();
 190         suspend_console();
 191         error = device_suspend(PMSG_PRETHAW);
 192         if (error)
 193                 goto Finish;
 194
 195         error = disable_nonboot_cpus();
 196         if (!error)
 197                 error = swsusp_resume();
 198
 199         enable_nonboot_cpus();
 200  Finish:
 201         device_resume();
 202         resume_console();
 203         pm_restore_console();
 204         mutex_unlock(&pm_mutex);
 205         return error;
 206 }
 207
 208 static int snapshot_ioctl(struct inode *inode, struct file *filp,
 209                           unsigned int cmd, unsigned long arg)
 210 {
 211         int error = 0;
 212         struct snapshot_data *data;
 213         loff_t avail;
 214         sector_t offset;
 215
 216         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
 217                 return -ENOTTY;
 218         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
 219                 return -ENOTTY;
 220         if (!capable(CAP_SYS_ADMIN))
 221                 return -EPERM;
 222
 223         data = filp->private_data;
 224
 225         switch (cmd) {
 226
 227         case SNAPSHOT_FREEZE:
 228                 if (data->frozen)
 229                         break;
 230                 mutex_lock(&pm_mutex);
 231                 if (freeze_processes()) {
 232                         thaw_processes();
 233                         error = -EBUSY;
 234                 }
 235                 mutex_unlock(&pm_mutex);
 236                 if (!error)
 237                         data->frozen = 1;
 238                 break;
 239
 240         case SNAPSHOT_UNFREEZE:
 241                 if (!data->frozen || data->ready)
 242                         break;
 243                 mutex_lock(&pm_mutex);
 244                 thaw_processes();
 245                 mutex_unlock(&pm_mutex);
 246                 data->frozen = 0;
 247                 break;
 248
 249         case SNAPSHOT_ATOMIC_SNAPSHOT:
 250                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
 251                         error = -EPERM;
 252                         break;
 253                 }
 254                 error = snapshot_suspend(data->platform_suspend);
 255                 if (!error)
 256                         error = put_user(in_suspend, (unsigned int __user *)arg);
 257                 if (!error)
 258                         data->ready = 1;
 259                 break;
 260
 261         case SNAPSHOT_ATOMIC_RESTORE:
 262                 snapshot_write_finalize(&data->handle);
 263                 if (data->mode != O_WRONLY || !data->frozen ||
 264                     !snapshot_image_loaded(&data->handle)) {
 265                         error = -EPERM;
 266                         break;
 267                 }
 268                 error = snapshot_restore();
 269                 break;
 270
 271         case SNAPSHOT_FREE:
 272                 swsusp_free();
 273                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
 274                 data->ready = 0;
 275                 break;
 276
 277         case SNAPSHOT_SET_IMAGE_SIZE:
 278                 image_size = arg;
 279                 break;
 280
 281         case SNAPSHOT_AVAIL_SWAP:
 282                 avail = count_swap_pages(data->swap, 1);
 283                 avail <<= PAGE_SHIFT;
 284                 error = put_user(avail, (loff_t __user *)arg);
 285                 break;
 286
 287         case SNAPSHOT_GET_SWAP_PAGE:
 288                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 289                         error = -ENODEV;
 290                         break;
 291                 }
 292                 offset = alloc_swapdev_block(data->swap);
 293                 if (offset) {
 294                         offset <<= PAGE_SHIFT;
 295                         error = put_user(offset, (sector_t __user *)arg);
 296                 } else {
 297                         error = -ENOSPC;
 298                 }
 299                 break;
 300
 301         case SNAPSHOT_FREE_SWAP_PAGES:
 302                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 303                         error = -ENODEV;
 304                         break;
 305                 }
 306                 free_all_swap_pages(data->swap);
 307                 break;
 308
 309         case SNAPSHOT_SET_SWAP_FILE:
 310                 if (!swsusp_swap_in_use()) {
 311                         /*
 312                          * User space encodes device types as two-byte values,
 313                          * so we need to recode them
 314                          */
 315                         if (old_decode_dev(arg)) {
 316                                 data->swap = swap_type_of(old_decode_dev(arg),
 317                                                         0, NULL);
 318                                 if (data->swap < 0)
 319                                         error = -ENODEV;
 320                         } else {
 321                                 data->swap = -1;
 322                                 error = -EINVAL;
 323                         }
 324                 } else {
 325                         error = -EPERM;
 326                 }
 327                 break;
 328
 329         case SNAPSHOT_S2RAM:
 330                 if (!pm_ops) {
 331                         error = -ENOSYS;
 332                         break;
 333                 }
 334
 335                 if (!data->frozen) {
 336                         error = -EPERM;
 337                         break;
 338                 }
 339
 340                 if (!mutex_trylock(&pm_mutex)) {
 341                         error = -EBUSY;
 342                         break;
 343                 }
 344
 345                 if (pm_ops->prepare) {
 346                         error = pm_ops->prepare(PM_SUSPEND_MEM);
 347                         if (error)
 348                                 goto OutS3;
 349                 }
 350
 351                 /* Put devices to sleep */
 352                 suspend_console();
 353                 error = device_suspend(PMSG_SUSPEND);
 354                 if (error) {
 355                         printk(KERN_ERR "Failed to suspend some devices.\n");
 356                 } else {
 357                         error = disable_nonboot_cpus();
 358                         if (!error) {
 359                                 /* Enter S3, system is already frozen */
 360                                 suspend_enter(PM_SUSPEND_MEM);
 361                                 enable_nonboot_cpus();
 362                         }
 363                         /* Wake up devices */
 364                         device_resume();
 365                 }
 366                 resume_console();
 367                 if (pm_ops->finish)
 368                         pm_ops->finish(PM_SUSPEND_MEM);
 369
 370  OutS3:
 371                 mutex_unlock(&pm_mutex);
 372                 break;
 373
 374         case SNAPSHOT_PMOPS:
 375                 error = -EINVAL;
 376
 377                 switch (arg) {
 378
 379                 case PMOPS_PREPARE:
 380                         if (hibernation_ops) {
 381                                 data->platform_suspend = 1;
 382                                 error = 0;
 383                         } else {
 384                                 error = -ENOSYS;
 385                         }
 386                         break;
 387
 388                 case PMOPS_ENTER:
 389                         if (data->platform_suspend) {
 390                                 kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
 391                                 error = hibernation_ops->enter();
 392                         }
 393                         break;
 394
 395                 case PMOPS_FINISH:
 396                         if (data->platform_suspend)
 397                                 error = 0;
 398
 399                         break;
 400
 401                 default:
 402                         printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
 403
 404                 }
 405                 break;
 406
 407         case SNAPSHOT_SET_SWAP_AREA:
 408                 if (swsusp_swap_in_use()) {
 409                         error = -EPERM;
 410                 } else {
 411                         struct resume_swap_area swap_area;
 412                         dev_t swdev;
 413
 414                         error = copy_from_user(&swap_area, (void __user *)arg,
 415                                         sizeof(struct resume_swap_area));
 416                         if (error) {
 417                                 error = -EFAULT;
 418                                 break;
 419                         }
 420
 421                         /*
 422                          * User space encodes device types as two-byte values,
 423                          * so we need to recode them
 424                          */
 425                         swdev = old_decode_dev(swap_area.dev);
 426                         if (swdev) {
 427                                 offset = swap_area.offset;
 428                                 data->swap = swap_type_of(swdev, offset, NULL);
 429                                 if (data->swap < 0)
 430                                         error = -ENODEV;
 431                         } else {
 432                                 data->swap = -1;
 433                                 error = -EINVAL;
 434                         }
 435                 }
 436                 break;
 437
 438         default:
 439                 error = -ENOTTY;
 440
 441         }
 442
 443         return error;
 444 }
 445
 446 static const struct file_operations snapshot_fops = {
 447         .open = snapshot_open,
 448         .release = snapshot_release,
 449         .read = snapshot_read,
 450         .write = snapshot_write,
 451         .llseek = no_llseek,
 452         .ioctl = snapshot_ioctl,
 453 };
 454
 455 static struct miscdevice snapshot_device = {
 456         .minor = SNAPSHOT_MINOR,
 457         .name = "snapshot",
 458         .fops = &snapshot_fops,
 459 };
 460
 461 static int __init snapshot_device_init(void)
 462 {
 463         return misc_register(&snapshot_device);
 464 };
 465
 466 device_initcall(snapshot_device_init);