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/kmod.h>
  16 #include <linux/string.h>
  17 #include <linux/device.h>
  18 #include <linux/miscdevice.h>
  19 #include <linux/mm.h>
  20 #include <linux/swap.h>
  21 #include <linux/swapops.h>
  22 #include <linux/pm.h>
  23 #include <linux/fs.h>
  24 #include <linux/console.h>
  25 #include <linux/cpu.h>
  26 #include <linux/freezer.h>
  27 #include <scsi/scsi_scan.h>
  28
  29 #include <asm/uaccess.h>
  30
  31 #include "power.h"
  32
  33 /*
  34  * NOTE: The SNAPSHOT_SET_SWAP_FILE and SNAPSHOT_PMOPS ioctls are obsolete and
  35  * will be removed in the future.  They are only preserved here for
  36  * compatibility with existing userland utilities.
  37  */
  38 #define SNAPSHOT_SET_SWAP_FILE  _IOW(SNAPSHOT_IOC_MAGIC, 10, unsigned int)
  39 #define SNAPSHOT_PMOPS          _IOW(SNAPSHOT_IOC_MAGIC, 12, unsigned int)
  40
  41 #define PMOPS_PREPARE   1
  42 #define PMOPS_ENTER     2
  43 #define PMOPS_FINISH    3
  44
  45 /*
  46  * NOTE: The following ioctl definitions are wrong and have been replaced with
  47  * correct ones.  They are only preserved here for compatibility with existing
  48  * userland utilities and will be removed in the future.
  49  */
  50 #define SNAPSHOT_ATOMIC_SNAPSHOT        _IOW(SNAPSHOT_IOC_MAGIC, 3, void *)
  51 #define SNAPSHOT_SET_IMAGE_SIZE         _IOW(SNAPSHOT_IOC_MAGIC, 6, unsigned long)
  52 #define SNAPSHOT_AVAIL_SWAP             _IOR(SNAPSHOT_IOC_MAGIC, 7, void *)
  53 #define SNAPSHOT_GET_SWAP_PAGE          _IOR(SNAPSHOT_IOC_MAGIC, 8, void *)
  54
  55
  56 #define SNAPSHOT_MINOR  231
  57
  58 static struct snapshot_data {
  59         struct snapshot_handle handle;
  60         int swap;
  61         int mode;
  62         char frozen;
  63         char ready;
  64         char platform_support;
  65 } snapshot_state;
  66
  67 atomic_t snapshot_device_available = ATOMIC_INIT(1);
  68
  69 static int snapshot_open(struct inode *inode, struct file *filp)
  70 {
  71         struct snapshot_data *data;
  72         int error;
  73
  74         mutex_lock(&pm_mutex);
  75
  76         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
  77                 error = -EBUSY;
  78                 goto Unlock;
  79         }
  80
  81         if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
  82                 atomic_inc(&snapshot_device_available);
  83                 error = -ENOSYS;
  84                 goto Unlock;
  85         }
  86         if(create_basic_memory_bitmaps()) {
  87                 atomic_inc(&snapshot_device_available);
  88                 error = -ENOMEM;
  89                 goto Unlock;
  90         }
  91         nonseekable_open(inode, filp);
  92         data = &snapshot_state;
  93         filp->private_data = data;
  94         memset(&data->handle, 0, sizeof(struct snapshot_handle));
  95         if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
  96                 /* Hibernating.  The image device should be accessible. */
  97                 data->swap = swsusp_resume_device ?
  98                         swap_type_of(swsusp_resume_device, 0, NULL) : -1;
  99                 data->mode = O_RDONLY;
 100                 error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
 101                 if (error)
 102                         pm_notifier_call_chain(PM_POST_HIBERNATION);
 103         } else {
 104                 /*
 105                  * Resuming.  We may need to wait for the image device to
 106                  * appear.
 107                  */
 108                 wait_for_device_probe();
 109                 scsi_complete_async_scans();
 110
 111                 data->swap = -1;
 112                 data->mode = O_WRONLY;
 113                 error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
 114                 if (error)
 115                         pm_notifier_call_chain(PM_POST_RESTORE);
 116         }
 117         if (error) {
 118                 free_basic_memory_bitmaps();
 119                 atomic_inc(&snapshot_device_available);
 120         }
 121         data->frozen = 0;
 122         data->ready = 0;
 123         data->platform_support = 0;
 124
 125  Unlock:
 126         mutex_unlock(&pm_mutex);
 127
 128         return error;
 129 }
 130
 131 static int snapshot_release(struct inode *inode, struct file *filp)
 132 {
 133         struct snapshot_data *data;
 134
 135         mutex_lock(&pm_mutex);
 136
 137         swsusp_free();
 138         free_basic_memory_bitmaps();
 139         data = filp->private_data;
 140         free_all_swap_pages(data->swap);
 141         if (data->frozen) {
 142                 pm_restore_gfp_mask();
 143                 thaw_processes();
 144         }
 145         pm_notifier_call_chain(data->mode == O_RDONLY ?
 146                         PM_POST_HIBERNATION : PM_POST_RESTORE);
 147         atomic_inc(&snapshot_device_available);
 148
 149         mutex_unlock(&pm_mutex);
 150
 151         return 0;
 152 }
 153
 154 static ssize_t snapshot_read(struct file *filp, char __user *buf,
 155                              size_t count, loff_t *offp)
 156 {
 157         struct snapshot_data *data;
 158         ssize_t res;
 159         loff_t pg_offp = *offp & ~PAGE_MASK;
 160
 161         mutex_lock(&pm_mutex);
 162
 163         data = filp->private_data;
 164         if (!data->ready) {
 165                 res = -ENODATA;
 166                 goto Unlock;
 167         }
 168         if (!pg_offp) { /* on page boundary? */
 169                 res = snapshot_read_next(&data->handle);
 170                 if (res <= 0)
 171                         goto Unlock;
 172         } else {
 173                 res = PAGE_SIZE - pg_offp;
 174         }
 175
 176         res = simple_read_from_buffer(buf, count, &pg_offp,
 177                         data_of(data->handle), res);
 178         if (res > 0)
 179                 *offp += res;
 180
 181  Unlock:
 182         mutex_unlock(&pm_mutex);
 183
 184         return res;
 185 }
 186
 187 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
 188                               size_t count, loff_t *offp)
 189 {
 190         struct snapshot_data *data;
 191         ssize_t res;
 192         loff_t pg_offp = *offp & ~PAGE_MASK;
 193
 194         mutex_lock(&pm_mutex);
 195
 196         data = filp->private_data;
 197
 198         if (!pg_offp) {
 199                 res = snapshot_write_next(&data->handle);
 200                 if (res <= 0)
 201                         goto unlock;
 202         } else {
 203                 res = PAGE_SIZE - pg_offp;
 204         }
 205
 206         res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
 207                         buf, count);
 208         if (res > 0)
 209                 *offp += res;
 210 unlock:
 211         mutex_unlock(&pm_mutex);
 212
 213         return res;
 214 }
 215
 216 static void snapshot_deprecated_ioctl(unsigned int cmd)
 217 {
 218         if (printk_ratelimit())
 219                 printk(KERN_NOTICE "%pf: ioctl '%.8x' is deprecated and will "
 220                                 "be removed soon, update your suspend-to-disk "
 221                                 "utilities\n",
 222                                 __builtin_return_address(0), cmd);
 223 }
 224
 225 static long snapshot_ioctl(struct file *filp, unsigned int cmd,
 226                                                         unsigned long arg)
 227 {
 228         int error = 0;
 229         struct snapshot_data *data;
 230         loff_t size;
 231         sector_t offset;
 232
 233         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
 234                 return -ENOTTY;
 235         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
 236                 return -ENOTTY;
 237         if (!capable(CAP_SYS_ADMIN))
 238                 return -EPERM;
 239
 240         if (!mutex_trylock(&pm_mutex))
 241                 return -EBUSY;
 242
 243         data = filp->private_data;
 244
 245         switch (cmd) {
 246
 247         case SNAPSHOT_FREEZE:
 248                 if (data->frozen)
 249                         break;
 250
 251                 printk("Syncing filesystems ... ");
 252                 sys_sync();
 253                 printk("done.\n");
 254
 255                 error = usermodehelper_disable();
 256                 if (error)
 257                         break;
 258
 259                 error = freeze_processes();
 260                 if (error) {
 261                         thaw_processes();
 262                         usermodehelper_enable();
 263                 }
 264                 if (!error)
 265                         data->frozen = 1;
 266                 break;
 267
 268         case SNAPSHOT_UNFREEZE:
 269                 if (!data->frozen || data->ready)
 270                         break;
 271                 pm_restore_gfp_mask();
 272                 thaw_processes();
 273                 usermodehelper_enable();
 274                 data->frozen = 0;
 275                 break;
 276
 277         case SNAPSHOT_ATOMIC_SNAPSHOT:
 278                 snapshot_deprecated_ioctl(cmd);
 279         case SNAPSHOT_CREATE_IMAGE:
 280                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
 281                         error = -EPERM;
 282                         break;
 283                 }
 284                 pm_restore_gfp_mask();
 285                 error = hibernation_snapshot(data->platform_support);
 286                 if (error) {
 287                         thaw_kernel_threads();
 288                 } else {
 289                         error = put_user(in_suspend, (int __user *)arg);
 290                         if (!error && !freezer_test_done)
 291                                 data->ready = 1;
 292                         if (freezer_test_done) {
 293                                 freezer_test_done = false;
 294                                 thaw_kernel_threads();
 295                         }
 296                 }
 297                 break;
 298
 299         case SNAPSHOT_ATOMIC_RESTORE:
 300                 snapshot_write_finalize(&data->handle);
 301                 if (data->mode != O_WRONLY || !data->frozen ||
 302                     !snapshot_image_loaded(&data->handle)) {
 303                         error = -EPERM;
 304                         break;
 305                 }
 306                 error = hibernation_restore(data->platform_support);
 307                 break;
 308
 309         case SNAPSHOT_FREE:
 310                 swsusp_free();
 311                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
 312                 data->ready = 0;
 313                 /*
 314                  * It is necessary to thaw kernel threads here, because
 315                  * SNAPSHOT_CREATE_IMAGE may be invoked directly after
 316                  * SNAPSHOT_FREE.  In that case, if kernel threads were not
 317                  * thawed, the preallocation of memory carried out by
 318                  * hibernation_snapshot() might run into problems (i.e. it
 319                  * might fail or even deadlock).
 320                  */
 321                 thaw_kernel_threads();
 322                 break;
 323
 324         case SNAPSHOT_SET_IMAGE_SIZE:
 325                 snapshot_deprecated_ioctl(cmd);
 326         case SNAPSHOT_PREF_IMAGE_SIZE:
 327                 image_size = arg;
 328                 break;
 329
 330         case SNAPSHOT_GET_IMAGE_SIZE:
 331                 if (!data->ready) {
 332                         error = -ENODATA;
 333                         break;
 334                 }
 335                 size = snapshot_get_image_size();
 336                 size <<= PAGE_SHIFT;
 337                 error = put_user(size, (loff_t __user *)arg);
 338                 break;
 339
 340         case SNAPSHOT_AVAIL_SWAP:
 341                 snapshot_deprecated_ioctl(cmd);
 342         case SNAPSHOT_AVAIL_SWAP_SIZE:
 343                 size = count_swap_pages(data->swap, 1);
 344                 size <<= PAGE_SHIFT;
 345                 error = put_user(size, (loff_t __user *)arg);
 346                 break;
 347
 348         case SNAPSHOT_GET_SWAP_PAGE:
 349                 snapshot_deprecated_ioctl(cmd);
 350         case SNAPSHOT_ALLOC_SWAP_PAGE:
 351                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 352                         error = -ENODEV;
 353                         break;
 354                 }
 355                 offset = alloc_swapdev_block(data->swap);
 356                 if (offset) {
 357                         offset <<= PAGE_SHIFT;
 358                         error = put_user(offset, (loff_t __user *)arg);
 359                 } else {
 360                         error = -ENOSPC;
 361                 }
 362                 break;
 363
 364         case SNAPSHOT_FREE_SWAP_PAGES:
 365                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
 366                         error = -ENODEV;
 367                         break;
 368                 }
 369                 free_all_swap_pages(data->swap);
 370                 break;
 371
 372         case SNAPSHOT_SET_SWAP_FILE: /* This ioctl is deprecated */
 373                 snapshot_deprecated_ioctl(cmd);
 374                 if (!swsusp_swap_in_use()) {
 375                         /*
 376                          * User space encodes device types as two-byte values,
 377                          * so we need to recode them
 378                          */
 379                         if (old_decode_dev(arg)) {
 380                                 data->swap = swap_type_of(old_decode_dev(arg),
 381                                                         0, NULL);
 382                                 if (data->swap < 0)
 383                                         error = -ENODEV;
 384                         } else {
 385                                 data->swap = -1;
 386                                 error = -EINVAL;
 387                         }
 388                 } else {
 389                         error = -EPERM;
 390                 }
 391                 break;
 392
 393         case SNAPSHOT_S2RAM:
 394                 if (!data->frozen) {
 395                         error = -EPERM;
 396                         break;
 397                 }
 398                 /*
 399                  * Tasks are frozen and the notifiers have been called with
 400                  * PM_HIBERNATION_PREPARE
 401                  */
 402                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 403                 data->ready = 0;
 404                 break;
 405
 406         case SNAPSHOT_PLATFORM_SUPPORT:
 407                 data->platform_support = !!arg;
 408                 break;
 409
 410         case SNAPSHOT_POWER_OFF:
 411                 if (data->platform_support)
 412                         error = hibernation_platform_enter();
 413                 break;
 414
 415         case SNAPSHOT_PMOPS: /* This ioctl is deprecated */
 416                 snapshot_deprecated_ioctl(cmd);
 417                 error = -EINVAL;
 418
 419                 switch (arg) {
 420
 421                 case PMOPS_PREPARE:
 422                         data->platform_support = 1;
 423                         error = 0;
 424                         break;
 425
 426                 case PMOPS_ENTER:
 427                         if (data->platform_support)
 428                                 error = hibernation_platform_enter();
 429                         break;
 430
 431                 case PMOPS_FINISH:
 432                         if (data->platform_support)
 433                                 error = 0;
 434                         break;
 435
 436                 default:
 437                         printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
 438
 439                 }
 440                 break;
 441
 442         case SNAPSHOT_SET_SWAP_AREA:
 443                 if (swsusp_swap_in_use()) {
 444                         error = -EPERM;
 445                 } else {
 446                         struct resume_swap_area swap_area;
 447                         dev_t swdev;
 448
 449                         error = copy_from_user(&swap_area, (void __user *)arg,
 450                                         sizeof(struct resume_swap_area));
 451                         if (error) {
 452                                 error = -EFAULT;
 453                                 break;
 454                         }
 455
 456                         /*
 457                          * User space encodes device types as two-byte values,
 458                          * so we need to recode them
 459                          */
 460                         swdev = new_decode_dev(swap_area.dev);
 461                         if (swdev) {
 462                                 offset = swap_area.offset;
 463                                 data->swap = swap_type_of(swdev, offset, NULL);
 464                                 if (data->swap < 0)
 465                                         error = -ENODEV;
 466                         } else {
 467                                 data->swap = -1;
 468                                 error = -EINVAL;
 469                         }
 470                 }
 471                 break;
 472
 473         default:
 474                 error = -ENOTTY;
 475
 476         }
 477
 478         mutex_unlock(&pm_mutex);
 479
 480         return error;
 481 }
 482
 483 static const struct file_operations snapshot_fops = {
 484         .open = snapshot_open,
 485         .release = snapshot_release,
 486         .read = snapshot_read,
 487         .write = snapshot_write,
 488         .llseek = no_llseek,
 489         .unlocked_ioctl = snapshot_ioctl,
 490 };
 491
 492 static struct miscdevice snapshot_device = {
 493         .minor = SNAPSHOT_MINOR,
 494         .name = "snapshot",
 495         .fops = &snapshot_fops,
 496 };
 497
 498 static int __init snapshot_device_init(void)
 499 {
 500         return misc_register(&snapshot_device);
 501 };
 502
 503 device_initcall(snapshot_device_init);