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 int snapshot_ioctl(struct inode *inode, struct file *filp,
 132                           unsigned int cmd, unsigned long arg)
 133 {
 134         int error = 0;
 135         struct snapshot_data *data;
 136         loff_t avail;
 137         sector_t offset;
 138
 139         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
 140                 return -ENOTTY;
 141         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
 142                 return -ENOTTY;
 143         if (!capable(CAP_SYS_ADMIN))
 144                 return -EPERM;
 145
 146         data = filp->private_data;
 147
 148         switch (cmd) {
 149
 150         case SNAPSHOT_FREEZE:
 151                 if (data->frozen)
 152                         break;
 153                 mutex_lock(&pm_mutex);
 154                 if (freeze_processes()) {
 155                         thaw_processes();
 156                         error = -EBUSY;
 157                 }
 158                 mutex_unlock(&pm_mutex);
 159                 if (!error)
 160                         data->frozen = 1;
 161                 break;
 162
 163         case SNAPSHOT_UNFREEZE:
 164                 if (!data->frozen || data->ready)
 165                         break;
 166                 mutex_lock(&pm_mutex);
 167                 thaw_processes();
 168                 mutex_unlock(&pm_mutex);
 169                 data->frozen = 0;
 170                 break;
 171
 172         case SNAPSHOT_ATOMIC_SNAPSHOT:
 173                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
 174                         error = -EPERM;
 175                         break;
 176                 }
 177                 error = hibernation_snapshot(data->platform_suspend);
 178                 if (!error)
 179                         error = put_user(in_suspend, (unsigned int __user *)arg);
 180                 if (!error)
 181                         data->ready = 1;
 182                 break;
 183
 184         case SNAPSHOT_ATOMIC_RESTORE:
 185                 snapshot_write_finalize(&data->handle);
 186                 if (data->mode != O_WRONLY || !data->frozen ||
 187                     !snapshot_image_loaded(&data->handle)) {
 188                         error = -EPERM;
 189                         break;
 190                 }
 191                 error = hibernation_restore(data->platform_suspend);
 192                 break;
 193
 194         case SNAPSHOT_FREE:
 195                 swsusp_free();
 196                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
 197                 data->ready = 0;
 198                 break;
 199
 200         case SNAPSHOT_SET_IMAGE_SIZE:
 201                 image_size = arg;
 202                 break;
 203
 204         case SNAPSHOT_AVAIL_SWAP:
 205                 avail = count_swap_pages(data->swap, 1);
 206                 avail <<= PAGE_SHIFT;
 207                 error = put_user(avail, (loff_t __user *)arg);
 208                 break;
 209
 210         case SNAPSHOT_GET_SWAP_PAGE:
 211                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 212                         error = -ENODEV;
 213                         break;
 214                 }
 215                 offset = alloc_swapdev_block(data->swap);
 216                 if (offset) {
 217                         offset <<= PAGE_SHIFT;
 218                         error = put_user(offset, (sector_t __user *)arg);
 219                 } else {
 220                         error = -ENOSPC;
 221                 }
 222                 break;
 223
 224         case SNAPSHOT_FREE_SWAP_PAGES:
 225                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 226                         error = -ENODEV;
 227                         break;
 228                 }
 229                 free_all_swap_pages(data->swap);
 230                 break;
 231
 232         case SNAPSHOT_SET_SWAP_FILE:
 233                 if (!swsusp_swap_in_use()) {
 234                         /*
 235                          * User space encodes device types as two-byte values,
 236                          * so we need to recode them
 237                          */
 238                         if (old_decode_dev(arg)) {
 239                                 data->swap = swap_type_of(old_decode_dev(arg),
 240                                                         0, NULL);
 241                                 if (data->swap < 0)
 242                                         error = -ENODEV;
 243                         } else {
 244                                 data->swap = -1;
 245                                 error = -EINVAL;
 246                         }
 247                 } else {
 248                         error = -EPERM;
 249                 }
 250                 break;
 251
 252         case SNAPSHOT_S2RAM:
 253                 if (!pm_ops) {
 254                         error = -ENOSYS;
 255                         break;
 256                 }
 257
 258                 if (!data->frozen) {
 259                         error = -EPERM;
 260                         break;
 261                 }
 262
 263                 if (!mutex_trylock(&pm_mutex)) {
 264                         error = -EBUSY;
 265                         break;
 266                 }
 267
 268                 if (pm_ops->prepare) {
 269                         error = pm_ops->prepare(PM_SUSPEND_MEM);
 270                         if (error)
 271                                 goto OutS3;
 272                 }
 273
 274                 /* Put devices to sleep */
 275                 suspend_console();
 276                 error = device_suspend(PMSG_SUSPEND);
 277                 if (error) {
 278                         printk(KERN_ERR "Failed to suspend some devices.\n");
 279                 } else {
 280                         error = disable_nonboot_cpus();
 281                         if (!error) {
 282                                 /* Enter S3, system is already frozen */
 283                                 suspend_enter(PM_SUSPEND_MEM);
 284                                 enable_nonboot_cpus();
 285                         }
 286                         /* Wake up devices */
 287                         device_resume();
 288                 }
 289                 resume_console();
 290                 if (pm_ops->finish)
 291                         pm_ops->finish(PM_SUSPEND_MEM);
 292
 293  OutS3:
 294                 mutex_unlock(&pm_mutex);
 295                 break;
 296
 297         case SNAPSHOT_PMOPS:
 298                 error = -EINVAL;
 299
 300                 switch (arg) {
 301
 302                 case PMOPS_PREPARE:
 303                         data->platform_suspend = 1;
 304                         error = 0;
 305                         break;
 306
 307                 case PMOPS_ENTER:
 308                         if (data->platform_suspend)
 309                                 error = hibernation_platform_enter();
 310
 311                         break;
 312
 313                 case PMOPS_FINISH:
 314                         if (data->platform_suspend)
 315                                 error = 0;
 316
 317                         break;
 318
 319                 default:
 320                         printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
 321
 322                 }
 323                 break;
 324
 325         case SNAPSHOT_SET_SWAP_AREA:
 326                 if (swsusp_swap_in_use()) {
 327                         error = -EPERM;
 328                 } else {
 329                         struct resume_swap_area swap_area;
 330                         dev_t swdev;
 331
 332                         error = copy_from_user(&swap_area, (void __user *)arg,
 333                                         sizeof(struct resume_swap_area));
 334                         if (error) {
 335                                 error = -EFAULT;
 336                                 break;
 337                         }
 338
 339                         /*
 340                          * User space encodes device types as two-byte values,
 341                          * so we need to recode them
 342                          */
 343                         swdev = old_decode_dev(swap_area.dev);
 344                         if (swdev) {
 345                                 offset = swap_area.offset;
 346                                 data->swap = swap_type_of(swdev, offset, NULL);
 347                                 if (data->swap < 0)
 348                                         error = -ENODEV;
 349                         } else {
 350                                 data->swap = -1;
 351                                 error = -EINVAL;
 352                         }
 353                 }
 354                 break;
 355
 356         default:
 357                 error = -ENOTTY;
 358
 359         }
 360
 361         return error;
 362 }
 363
 364 static const struct file_operations snapshot_fops = {
 365         .open = snapshot_open,
 366         .release = snapshot_release,
 367         .read = snapshot_read,
 368         .write = snapshot_write,
 369         .llseek = no_llseek,
 370         .ioctl = snapshot_ioctl,
 371 };
 372
 373 static struct miscdevice snapshot_device = {
 374         .minor = SNAPSHOT_MINOR,
 375         .name = "snapshot",
 376         .fops = &snapshot_fops,
 377 };
 378
 379 static int __init snapshot_device_init(void)
 380 {
 381         return misc_register(&snapshot_device);
 382 };
 383
 384 device_initcall(snapshot_device_init);