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 /*
  32  * NOTE: The SNAPSHOT_PMOPS ioctl is obsolete and will be removed in the
  33  * future.  It is only preserved here for compatibility with existing userland
  34  * utilities.
  35  */
  36 #define SNAPSHOT_PMOPS          _IOW(SNAPSHOT_IOC_MAGIC, 12, unsigned int)
  37
  38 #define PMOPS_PREPARE   1
  39 #define PMOPS_ENTER     2
  40 #define PMOPS_FINISH    3
  41
  42
  43 #define SNAPSHOT_MINOR  231
  44
  45 static struct snapshot_data {
  46         struct snapshot_handle handle;
  47         int swap;
  48         int mode;
  49         char frozen;
  50         char ready;
  51         char platform_support;
  52 } snapshot_state;
  53
  54 atomic_t snapshot_device_available = ATOMIC_INIT(1);
  55
  56 static int snapshot_open(struct inode *inode, struct file *filp)
  57 {
  58         struct snapshot_data *data;
  59
  60         if (!atomic_add_unless(&snapshot_device_available, -1, 0))
  61                 return -EBUSY;
  62
  63         if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
  64                 atomic_inc(&snapshot_device_available);
  65                 return -ENOSYS;
  66         }
  67         if(create_basic_memory_bitmaps()) {
  68                 atomic_inc(&snapshot_device_available);
  69                 return -ENOMEM;
  70         }
  71         nonseekable_open(inode, filp);
  72         data = &snapshot_state;
  73         filp->private_data = data;
  74         memset(&data->handle, 0, sizeof(struct snapshot_handle));
  75         if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
  76                 data->swap = swsusp_resume_device ?
  77                         swap_type_of(swsusp_resume_device, 0, NULL) : -1;
  78                 data->mode = O_RDONLY;
  79         } else {
  80                 data->swap = -1;
  81                 data->mode = O_WRONLY;
  82         }
  83         data->frozen = 0;
  84         data->ready = 0;
  85         data->platform_support = 0;
  86
  87         return 0;
  88 }
  89
  90 static int snapshot_release(struct inode *inode, struct file *filp)
  91 {
  92         struct snapshot_data *data;
  93
  94         swsusp_free();
  95         free_basic_memory_bitmaps();
  96         data = filp->private_data;
  97         free_all_swap_pages(data->swap);
  98         if (data->frozen) {
  99                 mutex_lock(&pm_mutex);
 100                 thaw_processes();
 101                 mutex_unlock(&pm_mutex);
 102         }
 103         atomic_inc(&snapshot_device_available);
 104         return 0;
 105 }
 106
 107 static ssize_t snapshot_read(struct file *filp, char __user *buf,
 108                              size_t count, loff_t *offp)
 109 {
 110         struct snapshot_data *data;
 111         ssize_t res;
 112
 113         data = filp->private_data;
 114         if (!data->ready)
 115                 return -ENODATA;
 116         res = snapshot_read_next(&data->handle, count);
 117         if (res > 0) {
 118                 if (copy_to_user(buf, data_of(data->handle), res))
 119                         res = -EFAULT;
 120                 else
 121                         *offp = data->handle.offset;
 122         }
 123         return res;
 124 }
 125
 126 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
 127                               size_t count, loff_t *offp)
 128 {
 129         struct snapshot_data *data;
 130         ssize_t res;
 131
 132         data = filp->private_data;
 133         res = snapshot_write_next(&data->handle, count);
 134         if (res > 0) {
 135                 if (copy_from_user(data_of(data->handle), buf, res))
 136                         res = -EFAULT;
 137                 else
 138                         *offp = data->handle.offset;
 139         }
 140         return res;
 141 }
 142
 143 static int snapshot_ioctl(struct inode *inode, struct file *filp,
 144                           unsigned int cmd, unsigned long arg)
 145 {
 146         int error = 0;
 147         struct snapshot_data *data;
 148         loff_t size;
 149         sector_t offset;
 150
 151         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
 152                 return -ENOTTY;
 153         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
 154                 return -ENOTTY;
 155         if (!capable(CAP_SYS_ADMIN))
 156                 return -EPERM;
 157
 158         data = filp->private_data;
 159
 160         switch (cmd) {
 161
 162         case SNAPSHOT_FREEZE:
 163                 if (data->frozen)
 164                         break;
 165                 mutex_lock(&pm_mutex);
 166                 error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
 167                 if (!error) {
 168                         printk("Syncing filesystems ... ");
 169                         sys_sync();
 170                         printk("done.\n");
 171
 172                         error = freeze_processes();
 173                         if (error)
 174                                 thaw_processes();
 175                 }
 176                 if (error)
 177                         pm_notifier_call_chain(PM_POST_HIBERNATION);
 178                 mutex_unlock(&pm_mutex);
 179                 if (!error)
 180                         data->frozen = 1;
 181                 break;
 182
 183         case SNAPSHOT_UNFREEZE:
 184                 if (!data->frozen || data->ready)
 185                         break;
 186                 mutex_lock(&pm_mutex);
 187                 thaw_processes();
 188                 pm_notifier_call_chain(PM_POST_HIBERNATION);
 189                 mutex_unlock(&pm_mutex);
 190                 data->frozen = 0;
 191                 break;
 192
 193         case SNAPSHOT_ATOMIC_SNAPSHOT:
 194                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
 195                         error = -EPERM;
 196                         break;
 197                 }
 198                 error = hibernation_snapshot(data->platform_support);
 199                 if (!error)
 200                         error = put_user(in_suspend, (unsigned int __user *)arg);
 201                 if (!error)
 202                         data->ready = 1;
 203                 break;
 204
 205         case SNAPSHOT_ATOMIC_RESTORE:
 206                 snapshot_write_finalize(&data->handle);
 207                 if (data->mode != O_WRONLY || !data->frozen ||
 208                     !snapshot_image_loaded(&data->handle)) {
 209                         error = -EPERM;
 210                         break;
 211                 }
 212                 error = hibernation_restore(data->platform_support);
 213                 break;
 214
 215         case SNAPSHOT_FREE:
 216                 swsusp_free();
 217                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
 218                 data->ready = 0;
 219                 break;
 220
 221         case SNAPSHOT_SET_IMAGE_SIZE:
 222                 image_size = arg;
 223                 break;
 224
 225         case SNAPSHOT_GET_IMAGE_SIZE:
 226                 if (!data->ready) {
 227                         error = -ENODATA;
 228                         break;
 229                 }
 230                 size = snapshot_get_image_size();
 231                 size <<= PAGE_SHIFT;
 232                 error = put_user(size, (loff_t __user *)arg);
 233                 break;
 234
 235         case SNAPSHOT_AVAIL_SWAP:
 236                 size = count_swap_pages(data->swap, 1);
 237                 size <<= PAGE_SHIFT;
 238                 error = put_user(size, (loff_t __user *)arg);
 239                 break;
 240
 241         case SNAPSHOT_GET_SWAP_PAGE:
 242                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 243                         error = -ENODEV;
 244                         break;
 245                 }
 246                 offset = alloc_swapdev_block(data->swap);
 247                 if (offset) {
 248                         offset <<= PAGE_SHIFT;
 249                         error = put_user(offset, (sector_t __user *)arg);
 250                 } else {
 251                         error = -ENOSPC;
 252                 }
 253                 break;
 254
 255         case SNAPSHOT_FREE_SWAP_PAGES:
 256                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 257                         error = -ENODEV;
 258                         break;
 259                 }
 260                 free_all_swap_pages(data->swap);
 261                 break;
 262
 263         case SNAPSHOT_SET_SWAP_FILE:
 264                 if (!swsusp_swap_in_use()) {
 265                         /*
 266                          * User space encodes device types as two-byte values,
 267                          * so we need to recode them
 268                          */
 269                         if (old_decode_dev(arg)) {
 270                                 data->swap = swap_type_of(old_decode_dev(arg),
 271                                                         0, NULL);
 272                                 if (data->swap < 0)
 273                                         error = -ENODEV;
 274                         } else {
 275                                 data->swap = -1;
 276                                 error = -EINVAL;
 277                         }
 278                 } else {
 279                         error = -EPERM;
 280                 }
 281                 break;
 282
 283         case SNAPSHOT_S2RAM:
 284                 if (!data->frozen) {
 285                         error = -EPERM;
 286                         break;
 287                 }
 288                 if (!mutex_trylock(&pm_mutex)) {
 289                         error = -EBUSY;
 290                         break;
 291                 }
 292                 /*
 293                  * Tasks are frozen and the notifiers have been called with
 294                  * PM_HIBERNATION_PREPARE
 295                  */
 296                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 297                 mutex_unlock(&pm_mutex);
 298                 break;
 299
 300         case SNAPSHOT_PLATFORM_SUPPORT:
 301                 data->platform_support = !!arg;
 302                 break;
 303
 304         case SNAPSHOT_POWER_OFF:
 305                 if (data->platform_support)
 306                         error = hibernation_platform_enter();
 307                 break;
 308
 309         case SNAPSHOT_PMOPS: /* This ioctl is deprecated */
 310                 error = -EINVAL;
 311
 312                 switch (arg) {
 313
 314                 case PMOPS_PREPARE:
 315                         data->platform_support = 1;
 316                         error = 0;
 317                         break;
 318
 319                 case PMOPS_ENTER:
 320                         if (data->platform_support)
 321                                 error = hibernation_platform_enter();
 322                         break;
 323
 324                 case PMOPS_FINISH:
 325                         if (data->platform_support)
 326                                 error = 0;
 327                         break;
 328
 329                 default:
 330                         printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
 331
 332                 }
 333                 break;
 334
 335         case SNAPSHOT_SET_SWAP_AREA:
 336                 if (swsusp_swap_in_use()) {
 337                         error = -EPERM;
 338                 } else {
 339                         struct resume_swap_area swap_area;
 340                         dev_t swdev;
 341
 342                         error = copy_from_user(&swap_area, (void __user *)arg,
 343                                         sizeof(struct resume_swap_area));
 344                         if (error) {
 345                                 error = -EFAULT;
 346                                 break;
 347                         }
 348
 349                         /*
 350                          * User space encodes device types as two-byte values,
 351                          * so we need to recode them
 352                          */
 353                         swdev = old_decode_dev(swap_area.dev);
 354                         if (swdev) {
 355                                 offset = swap_area.offset;
 356                                 data->swap = swap_type_of(swdev, offset, NULL);
 357                                 if (data->swap < 0)
 358                                         error = -ENODEV;
 359                         } else {
 360                                 data->swap = -1;
 361                                 error = -EINVAL;
 362                         }
 363                 }
 364                 break;
 365
 366         default:
 367                 error = -ENOTTY;
 368
 369         }
 370
 371         return error;
 372 }
 373
 374 static const struct file_operations snapshot_fops = {
 375         .open = snapshot_open,
 376         .release = snapshot_release,
 377         .read = snapshot_read,
 378         .write = snapshot_write,
 379         .llseek = no_llseek,
 380         .ioctl = snapshot_ioctl,
 381 };
 382
 383 static struct miscdevice snapshot_device = {
 384         .minor = SNAPSHOT_MINOR,
 385         .name = "snapshot",
 386         .fops = &snapshot_fops,
 387 };
 388
 389 static int __init snapshot_device_init(void)
 390 {
 391         return misc_register(&snapshot_device);
 392 };
 393
 394 device_initcall(snapshot_device_init);