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