kernel/power/hibernate.c

   1 /*
   2  * kernel/power/hibernate.c - Hibernation (a.k.a suspend-to-disk) support.
   3  *
   4  * Copyright (c) 2003 Patrick Mochel
   5  * Copyright (c) 2003 Open Source Development Lab
   6  * Copyright (c) 2004 Pavel Machek <pavel@ucw.cz>
   7  * Copyright (c) 2009 Rafael J. Wysocki, Novell Inc.
   8  * Copyright (C) 2012 Bojan Smojver <bojan@rexursive.com>
   9  *
  10  * This file is released under the GPLv2.
  11  */
  12
  13 #include <linux/export.h>
  14 #include <linux/suspend.h>
  15 #include <linux/syscalls.h>
  16 #include <linux/reboot.h>
  17 #include <linux/string.h>
  18 #include <linux/device.h>
  19 #include <linux/async.h>
  20 #include <linux/delay.h>
  21 #include <linux/fs.h>
  22 #include <linux/mount.h>
  23 #include <linux/pm.h>
  24 #include <linux/console.h>
  25 #include <linux/cpu.h>
  26 #include <linux/freezer.h>
  27 #include <linux/gfp.h>
  28 #include <linux/syscore_ops.h>
  29 #include <linux/ctype.h>
  30 #include <linux/genhd.h>
  31 #include <trace/events/power.h>
  32
  33 #include "power.h"
  34
  35
  36 static int nocompress;
  37 static int noresume;
  38 static int nohibernate;
  39 static int resume_wait;
  40 static unsigned int resume_delay;
  41 static char resume_file[256] = CONFIG_PM_STD_PARTITION;
  42 dev_t swsusp_resume_device;
  43 sector_t swsusp_resume_block;
  44 __visible int in_suspend __nosavedata;
  45
  46 enum {
  47         HIBERNATION_INVALID,
  48         HIBERNATION_PLATFORM,
  49         HIBERNATION_SHUTDOWN,
  50         HIBERNATION_REBOOT,
  51 #ifdef CONFIG_SUSPEND
  52         HIBERNATION_SUSPEND,
  53 #endif
  54         /* keep last */
  55         __HIBERNATION_AFTER_LAST
  56 };
  57 #define HIBERNATION_MAX (__HIBERNATION_AFTER_LAST-1)
  58 #define HIBERNATION_FIRST (HIBERNATION_INVALID + 1)
  59
  60 static int hibernation_mode = HIBERNATION_SHUTDOWN;
  61
  62 bool freezer_test_done;
  63
  64 static const struct platform_hibernation_ops *hibernation_ops;
  65
  66 bool hibernation_available(void)
  67 {
  68         return (nohibernate == 0);
  69 }
  70
  71 /**
  72  * hibernation_set_ops - Set the global hibernate operations.
  73  * @ops: Hibernation operations to use in subsequent hibernation transitions.
  74  */
  75 void hibernation_set_ops(const struct platform_hibernation_ops *ops)
  76 {
  77         if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
  78             && ops->prepare && ops->finish && ops->enter && ops->pre_restore
  79             && ops->restore_cleanup && ops->leave)) {
  80                 WARN_ON(1);
  81                 return;
  82         }
  83         lock_system_sleep();
  84         hibernation_ops = ops;
  85         if (ops)
  86                 hibernation_mode = HIBERNATION_PLATFORM;
  87         else if (hibernation_mode == HIBERNATION_PLATFORM)
  88                 hibernation_mode = HIBERNATION_SHUTDOWN;
  89
  90         unlock_system_sleep();
  91 }
  92 EXPORT_SYMBOL_GPL(hibernation_set_ops);
  93
  94 static bool entering_platform_hibernation;
  95
  96 bool system_entering_hibernation(void)
  97 {
  98         return entering_platform_hibernation;
  99 }
 100 EXPORT_SYMBOL(system_entering_hibernation);
 101
 102 #ifdef CONFIG_PM_DEBUG
 103 static void hibernation_debug_sleep(void)
 104 {
 105         printk(KERN_INFO "hibernation debug: Waiting for 5 seconds.\n");
 106         mdelay(5000);
 107 }
 108
 109 static int hibernation_test(int level)
 110 {
 111         if (pm_test_level == level) {
 112                 hibernation_debug_sleep();
 113                 return 1;
 114         }
 115         return 0;
 116 }
 117 #else /* !CONFIG_PM_DEBUG */
 118 static int hibernation_test(int level) { return 0; }
 119 #endif /* !CONFIG_PM_DEBUG */
 120
 121 /**
 122  * platform_begin - Call platform to start hibernation.
 123  * @platform_mode: Whether or not to use the platform driver.
 124  */
 125 static int platform_begin(int platform_mode)
 126 {
 127         return (platform_mode && hibernation_ops) ?
 128                 hibernation_ops->begin() : 0;
 129 }
 130
 131 /**
 132  * platform_end - Call platform to finish transition to the working state.
 133  * @platform_mode: Whether or not to use the platform driver.
 134  */
 135 static void platform_end(int platform_mode)
 136 {
 137         if (platform_mode && hibernation_ops)
 138                 hibernation_ops->end();
 139 }
 140
 141 /**
 142  * platform_pre_snapshot - Call platform to prepare the machine for hibernation.
 143  * @platform_mode: Whether or not to use the platform driver.
 144  *
 145  * Use the platform driver to prepare the system for creating a hibernate image,
 146  * if so configured, and return an error code if that fails.
 147  */
 148
 149 static int platform_pre_snapshot(int platform_mode)
 150 {
 151         return (platform_mode && hibernation_ops) ?
 152                 hibernation_ops->pre_snapshot() : 0;
 153 }
 154
 155 /**
 156  * platform_leave - Call platform to prepare a transition to the working state.
 157  * @platform_mode: Whether or not to use the platform driver.
 158  *
 159  * Use the platform driver prepare to prepare the machine for switching to the
 160  * normal mode of operation.
 161  *
 162  * This routine is called on one CPU with interrupts disabled.
 163  */
 164 static void platform_leave(int platform_mode)
 165 {
 166         if (platform_mode && hibernation_ops)
 167                 hibernation_ops->leave();
 168 }
 169
 170 /**
 171  * platform_finish - Call platform to switch the system to the working state.
 172  * @platform_mode: Whether or not to use the platform driver.
 173  *
 174  * Use the platform driver to switch the machine to the normal mode of
 175  * operation.
 176  *
 177  * This routine must be called after platform_prepare().
 178  */
 179 static void platform_finish(int platform_mode)
 180 {
 181         if (platform_mode && hibernation_ops)
 182                 hibernation_ops->finish();
 183 }
 184
 185 /**
 186  * platform_pre_restore - Prepare for hibernate image restoration.
 187  * @platform_mode: Whether or not to use the platform driver.
 188  *
 189  * Use the platform driver to prepare the system for resume from a hibernation
 190  * image.
 191  *
 192  * If the restore fails after this function has been called,
 193  * platform_restore_cleanup() must be called.
 194  */
 195 static int platform_pre_restore(int platform_mode)
 196 {
 197         return (platform_mode && hibernation_ops) ?
 198                 hibernation_ops->pre_restore() : 0;
 199 }
 200
 201 /**
 202  * platform_restore_cleanup - Switch to the working state after failing restore.
 203  * @platform_mode: Whether or not to use the platform driver.
 204  *
 205  * Use the platform driver to switch the system to the normal mode of operation
 206  * after a failing restore.
 207  *
 208  * If platform_pre_restore() has been called before the failing restore, this
 209  * function must be called too, regardless of the result of
 210  * platform_pre_restore().
 211  */
 212 static void platform_restore_cleanup(int platform_mode)
 213 {
 214         if (platform_mode && hibernation_ops)
 215                 hibernation_ops->restore_cleanup();
 216 }
 217
 218 /**
 219  * platform_recover - Recover from a failure to suspend devices.
 220  * @platform_mode: Whether or not to use the platform driver.
 221  */
 222 static void platform_recover(int platform_mode)
 223 {
 224         if (platform_mode && hibernation_ops && hibernation_ops->recover)
 225                 hibernation_ops->recover();
 226 }
 227
 228 /**
 229  * swsusp_show_speed - Print time elapsed between two events during hibernation.
 230  * @start: Starting event.
 231  * @stop: Final event.
 232  * @nr_pages: Number of memory pages processed between @start and @stop.
 233  * @msg: Additional diagnostic message to print.
 234  */
 235 void swsusp_show_speed(struct timeval *start, struct timeval *stop,
 236                         unsigned nr_pages, char *msg)
 237 {
 238         u64 elapsed_centisecs64;
 239         unsigned int centisecs;
 240         unsigned int k;
 241         unsigned int kps;
 242
 243         elapsed_centisecs64 = timeval_to_ns(stop) - timeval_to_ns(start);
 244         /*
 245          * If "(s64)elapsed_centisecs64 < 0", it will print long elapsed time,
 246          * it is obvious enough for what went wrong.
 247          */
 248         do_div(elapsed_centisecs64, NSEC_PER_SEC / 100);
 249         centisecs = elapsed_centisecs64;
 250         if (centisecs == 0)
 251                 centisecs = 1;  /* avoid div-by-zero */
 252         k = nr_pages * (PAGE_SIZE / 1024);
 253         kps = (k * 100) / centisecs;
 254         printk(KERN_INFO "PM: %s %u kbytes in %u.%02u seconds (%u.%02u MB/s)\n",
 255                         msg, k,
 256                         centisecs / 100, centisecs % 100,
 257                         kps / 1000, (kps % 1000) / 10);
 258 }
 259
 260 /**
 261  * create_image - Create a hibernation image.
 262  * @platform_mode: Whether or not to use the platform driver.
 263  *
 264  * Execute device drivers' "late" and "noirq" freeze callbacks, create a
 265  * hibernation image and run the drivers' "noirq" and "early" thaw callbacks.
 266  *
 267  * Control reappears in this routine after the subsequent restore.
 268  */
 269 static int create_image(int platform_mode)
 270 {
 271         int error;
 272
 273         error = dpm_suspend_end(PMSG_FREEZE);
 274         if (error) {
 275                 printk(KERN_ERR "PM: Some devices failed to power down, "
 276                         "aborting hibernation\n");
 277                 return error;
 278         }
 279
 280         error = platform_pre_snapshot(platform_mode);
 281         if (error || hibernation_test(TEST_PLATFORM))
 282                 goto Platform_finish;
 283
 284         error = disable_nonboot_cpus();
 285         if (error || hibernation_test(TEST_CPUS))
 286                 goto Enable_cpus;
 287
 288         local_irq_disable();
 289
 290         error = syscore_suspend();
 291         if (error) {
 292                 printk(KERN_ERR "PM: Some system devices failed to power down, "
 293                         "aborting hibernation\n");
 294                 goto Enable_irqs;
 295         }
 296
 297         if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
 298                 goto Power_up;
 299
 300         in_suspend = 1;
 301         save_processor_state();
 302         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);
 303         error = swsusp_arch_suspend();
 304         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
 305         if (error)
 306                 printk(KERN_ERR "PM: Error %d creating hibernation image\n",
 307                         error);
 308         /* Restore control flow magically appears here */
 309         restore_processor_state();
 310         if (!in_suspend)
 311                 events_check_enabled = false;
 312
 313         platform_leave(platform_mode);
 314
 315  Power_up:
 316         syscore_resume();
 317
 318  Enable_irqs:
 319         local_irq_enable();
 320
 321  Enable_cpus:
 322         enable_nonboot_cpus();
 323
 324  Platform_finish:
 325         platform_finish(platform_mode);
 326
 327         dpm_resume_start(in_suspend ?
 328                 (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
 329
 330         return error;
 331 }
 332
 333 /**
 334  * hibernation_snapshot - Quiesce devices and create a hibernation image.
 335  * @platform_mode: If set, use platform driver to prepare for the transition.
 336  *
 337  * This routine must be called with pm_mutex held.
 338  */
 339 int hibernation_snapshot(int platform_mode)
 340 {
 341         pm_message_t msg;
 342         int error;
 343
 344         error = platform_begin(platform_mode);
 345         if (error)
 346                 goto Close;
 347
 348         /* Preallocate image memory before shutting down devices. */
 349         error = hibernate_preallocate_memory();
 350         if (error)
 351                 goto Close;
 352
 353         error = freeze_kernel_threads();
 354         if (error)
 355                 goto Cleanup;
 356
 357         if (hibernation_test(TEST_FREEZER)) {
 358
 359                 /*
 360                  * Indicate to the caller that we are returning due to a
 361                  * successful freezer test.
 362                  */
 363                 freezer_test_done = true;
 364                 goto Thaw;
 365         }
 366
 367         error = dpm_prepare(PMSG_FREEZE);
 368         if (error) {
 369                 dpm_complete(PMSG_RECOVER);
 370                 goto Thaw;
 371         }
 372
 373         suspend_console();
 374         pm_restrict_gfp_mask();
 375
 376         error = dpm_suspend(PMSG_FREEZE);
 377
 378         if (error || hibernation_test(TEST_DEVICES))
 379                 platform_recover(platform_mode);
 380         else
 381                 error = create_image(platform_mode);
 382
 383         /*
 384          * In the case that we call create_image() above, the control
 385          * returns here (1) after the image has been created or the
 386          * image creation has failed and (2) after a successful restore.
 387          */
 388
 389         /* We may need to release the preallocated image pages here. */
 390         if (error || !in_suspend)
 391                 swsusp_free();
 392
 393         msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
 394         dpm_resume(msg);
 395
 396         if (error || !in_suspend)
 397                 pm_restore_gfp_mask();
 398
 399         resume_console();
 400         dpm_complete(msg);
 401
 402  Close:
 403         platform_end(platform_mode);
 404         return error;
 405
 406  Thaw:
 407         thaw_kernel_threads();
 408  Cleanup:
 409         swsusp_free();
 410         goto Close;
 411 }
 412
 413 /**
 414  * resume_target_kernel - Restore system state from a hibernation image.
 415  * @platform_mode: Whether or not to use the platform driver.
 416  *
 417  * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
 418  * contents of highmem that have not been restored yet from the image and run
 419  * the low-level code that will restore the remaining contents of memory and
 420  * switch to the just restored target kernel.
 421  */
 422 static int resume_target_kernel(bool platform_mode)
 423 {
 424         int error;
 425
 426         error = dpm_suspend_end(PMSG_QUIESCE);
 427         if (error) {
 428                 printk(KERN_ERR "PM: Some devices failed to power down, "
 429                         "aborting resume\n");
 430                 return error;
 431         }
 432
 433         error = platform_pre_restore(platform_mode);
 434         if (error)
 435                 goto Cleanup;
 436
 437         error = disable_nonboot_cpus();
 438         if (error)
 439                 goto Enable_cpus;
 440
 441         local_irq_disable();
 442
 443         error = syscore_suspend();
 444         if (error)
 445                 goto Enable_irqs;
 446
 447         save_processor_state();
 448         error = restore_highmem();
 449         if (!error) {
 450                 error = swsusp_arch_resume();
 451                 /*
 452                  * The code below is only ever reached in case of a failure.
 453                  * Otherwise, execution continues at the place where
 454                  * swsusp_arch_suspend() was called.
 455                  */
 456                 BUG_ON(!error);
 457                 /*
 458                  * This call to restore_highmem() reverts the changes made by
 459                  * the previous one.
 460                  */
 461                 restore_highmem();
 462         }
 463         /*
 464          * The only reason why swsusp_arch_resume() can fail is memory being
 465          * very tight, so we have to free it as soon as we can to avoid
 466          * subsequent failures.
 467          */
 468         swsusp_free();
 469         restore_processor_state();
 470         touch_softlockup_watchdog();
 471
 472         syscore_resume();
 473
 474  Enable_irqs:
 475         local_irq_enable();
 476
 477  Enable_cpus:
 478         enable_nonboot_cpus();
 479
 480  Cleanup:
 481         platform_restore_cleanup(platform_mode);
 482
 483         dpm_resume_start(PMSG_RECOVER);
 484
 485         return error;
 486 }
 487
 488 /**
 489  * hibernation_restore - Quiesce devices and restore from a hibernation image.
 490  * @platform_mode: If set, use platform driver to prepare for the transition.
 491  *
 492  * This routine must be called with pm_mutex held.  If it is successful, control
 493  * reappears in the restored target kernel in hibernation_snapshot().
 494  */
 495 int hibernation_restore(int platform_mode)
 496 {
 497         int error;
 498
 499         pm_prepare_console();
 500         suspend_console();
 501         pm_restrict_gfp_mask();
 502         error = dpm_suspend_start(PMSG_QUIESCE);
 503         if (!error) {
 504                 error = resume_target_kernel(platform_mode);
 505                 dpm_resume_end(PMSG_RECOVER);
 506         }
 507         pm_restore_gfp_mask();
 508         resume_console();
 509         pm_restore_console();
 510         return error;
 511 }
 512
 513 /**
 514  * hibernation_platform_enter - Power off the system using the platform driver.
 515  */
 516 int hibernation_platform_enter(void)
 517 {
 518         int error;
 519
 520         if (!hibernation_ops)
 521                 return -ENOSYS;
 522
 523         /*
 524          * We have cancelled the power transition by running
 525          * hibernation_ops->finish() before saving the image, so we should let
 526          * the firmware know that we're going to enter the sleep state after all
 527          */
 528         error = hibernation_ops->begin();
 529         if (error)
 530                 goto Close;
 531
 532         entering_platform_hibernation = true;
 533         suspend_console();
 534         error = dpm_suspend_start(PMSG_HIBERNATE);
 535         if (error) {
 536                 if (hibernation_ops->recover)
 537                         hibernation_ops->recover();
 538                 goto Resume_devices;
 539         }
 540
 541         error = dpm_suspend_end(PMSG_HIBERNATE);
 542         if (error)
 543                 goto Resume_devices;
 544
 545         error = hibernation_ops->prepare();
 546         if (error)
 547                 goto Platform_finish;
 548
 549         error = disable_nonboot_cpus();
 550         if (error)
 551                 goto Platform_finish;
 552
 553         local_irq_disable();
 554         syscore_suspend();
 555         if (pm_wakeup_pending()) {
 556                 error = -EAGAIN;
 557                 goto Power_up;
 558         }
 559
 560         hibernation_ops->enter();
 561         /* We should never get here */
 562         while (1);
 563
 564  Power_up:
 565         syscore_resume();
 566         local_irq_enable();
 567         enable_nonboot_cpus();
 568
 569  Platform_finish:
 570         hibernation_ops->finish();
 571
 572         dpm_resume_start(PMSG_RESTORE);
 573
 574  Resume_devices:
 575         entering_platform_hibernation = false;
 576         dpm_resume_end(PMSG_RESTORE);
 577         resume_console();
 578
 579  Close:
 580         hibernation_ops->end();
 581
 582         return error;
 583 }
 584
 585 /**
 586  * power_down - Shut the machine down for hibernation.
 587  *
 588  * Use the platform driver, if configured, to put the system into the sleep
 589  * state corresponding to hibernation, or try to power it off or reboot,
 590  * depending on the value of hibernation_mode.
 591  */
 592 static void power_down(void)
 593 {
 594 #ifdef CONFIG_SUSPEND
 595         int error;
 596 #endif
 597
 598         switch (hibernation_mode) {
 599         case HIBERNATION_REBOOT:
 600                 kernel_restart(NULL);
 601                 break;
 602         case HIBERNATION_PLATFORM:
 603                 hibernation_platform_enter();
 604         case HIBERNATION_SHUTDOWN:
 605                 if (pm_power_off)
 606                         kernel_power_off();
 607                 break;
 608 #ifdef CONFIG_SUSPEND
 609         case HIBERNATION_SUSPEND:
 610                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 611                 if (error) {
 612                         if (hibernation_ops)
 613                                 hibernation_mode = HIBERNATION_PLATFORM;
 614                         else
 615                                 hibernation_mode = HIBERNATION_SHUTDOWN;
 616                         power_down();
 617                 }
 618                 /*
 619                  * Restore swap signature.
 620                  */
 621                 error = swsusp_unmark();
 622                 if (error)
 623                         printk(KERN_ERR "PM: Swap will be unusable! "
 624                                         "Try swapon -a.\n");
 625                 return;
 626 #endif
 627         }
 628         kernel_halt();
 629         /*
 630          * Valid image is on the disk, if we continue we risk serious data
 631          * corruption after resume.
 632          */
 633         printk(KERN_CRIT "PM: Please power down manually\n");
 634         while (1)
 635                 cpu_relax();
 636 }
 637
 638 /**
 639  * hibernate - Carry out system hibernation, including saving the image.
 640  */
 641 int hibernate(void)
 642 {
 643         int error;
 644
 645         if (!hibernation_available()) {
 646                 pr_debug("PM: Hibernation not available.\n");
 647                 return -EPERM;
 648         }
 649
 650         lock_system_sleep();
 651         /* The snapshot device should not be opened while we're running */
 652         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 653                 error = -EBUSY;
 654                 goto Unlock;
 655         }
 656
 657         pm_prepare_console();
 658         error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
 659         if (error)
 660                 goto Exit;
 661
 662         printk(KERN_INFO "PM: Syncing filesystems ... ");
 663         sys_sync();
 664         printk("done.\n");
 665
 666         error = freeze_processes();
 667         if (error)
 668                 goto Exit;
 669
 670         lock_device_hotplug();
 671         /* Allocate memory management structures */
 672         error = create_basic_memory_bitmaps();
 673         if (error)
 674                 goto Thaw;
 675
 676         error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
 677         if (error || freezer_test_done)
 678                 goto Free_bitmaps;
 679
 680         if (in_suspend) {
 681                 unsigned int flags = 0;
 682
 683                 if (hibernation_mode == HIBERNATION_PLATFORM)
 684                         flags |= SF_PLATFORM_MODE;
 685                 if (nocompress)
 686                         flags |= SF_NOCOMPRESS_MODE;
 687                 else
 688                         flags |= SF_CRC32_MODE;
 689
 690                 pr_debug("PM: writing image.\n");
 691                 error = swsusp_write(flags);
 692                 swsusp_free();
 693                 if (!error)
 694                         power_down();
 695                 in_suspend = 0;
 696                 pm_restore_gfp_mask();
 697         } else {
 698                 pr_debug("PM: Image restored successfully.\n");
 699         }
 700
 701  Free_bitmaps:
 702         free_basic_memory_bitmaps();
 703  Thaw:
 704         unlock_device_hotplug();
 705         thaw_processes();
 706
 707         /* Don't bother checking whether freezer_test_done is true */
 708         freezer_test_done = false;
 709  Exit:
 710         pm_notifier_call_chain(PM_POST_HIBERNATION);
 711         pm_restore_console();
 712         atomic_inc(&snapshot_device_available);
 713  Unlock:
 714         unlock_system_sleep();
 715         return error;
 716 }
 717
 718
 719 /**
 720  * software_resume - Resume from a saved hibernation image.
 721  *
 722  * This routine is called as a late initcall, when all devices have been
 723  * discovered and initialized already.
 724  *
 725  * The image reading code is called to see if there is a hibernation image
 726  * available for reading.  If that is the case, devices are quiesced and the
 727  * contents of memory is restored from the saved image.
 728  *
 729  * If this is successful, control reappears in the restored target kernel in
 730  * hibernation_snaphot() which returns to hibernate().  Otherwise, the routine
 731  * attempts to recover gracefully and make the kernel return to the normal mode
 732  * of operation.
 733  */
 734 static int software_resume(void)
 735 {
 736         int error;
 737         unsigned int flags;
 738
 739         /*
 740          * If the user said "noresume".. bail out early.
 741          */
 742         if (noresume || !hibernation_available())
 743                 return 0;
 744
 745         /*
 746          * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
 747          * is configured into the kernel. Since the regular hibernate
 748          * trigger path is via sysfs which takes a buffer mutex before
 749          * calling hibernate functions (which take pm_mutex) this can
 750          * cause lockdep to complain about a possible ABBA deadlock
 751          * which cannot happen since we're in the boot code here and
 752          * sysfs can't be invoked yet. Therefore, we use a subclass
 753          * here to avoid lockdep complaining.
 754          */
 755         mutex_lock_nested(&pm_mutex, SINGLE_DEPTH_NESTING);
 756
 757         if (swsusp_resume_device)
 758                 goto Check_image;
 759
 760         if (!strlen(resume_file)) {
 761                 error = -ENOENT;
 762                 goto Unlock;
 763         }
 764
 765         pr_debug("PM: Checking hibernation image partition %s\n", resume_file);
 766
 767         if (resume_delay) {
 768                 printk(KERN_INFO "Waiting %dsec before reading resume device...\n",
 769                         resume_delay);
 770                 ssleep(resume_delay);
 771         }
 772
 773         /* Check if the device is there */
 774         swsusp_resume_device = name_to_dev_t(resume_file);
 775
 776         /*
 777          * name_to_dev_t is ineffective to verify parition if resume_file is in
 778          * integer format. (e.g. major:minor)
 779          */
 780         if (isdigit(resume_file[0]) && resume_wait) {
 781                 int partno;
 782                 while (!get_gendisk(swsusp_resume_device, &partno))
 783                         msleep(10);
 784         }
 785
 786         if (!swsusp_resume_device) {
 787                 /*
 788                  * Some device discovery might still be in progress; we need
 789                  * to wait for this to finish.
 790                  */
 791                 wait_for_device_probe();
 792
 793                 if (resume_wait) {
 794                         while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
 795                                 msleep(10);
 796                         async_synchronize_full();
 797                 }
 798
 799                 swsusp_resume_device = name_to_dev_t(resume_file);
 800                 if (!swsusp_resume_device) {
 801                         error = -ENODEV;
 802                         goto Unlock;
 803                 }
 804         }
 805
 806  Check_image:
 807         pr_debug("PM: Hibernation image partition %d:%d present\n",
 808                 MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 809
 810         pr_debug("PM: Looking for hibernation image.\n");
 811         error = swsusp_check();
 812         if (error)
 813                 goto Unlock;
 814
 815         /* The snapshot device should not be opened while we're running */
 816         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 817                 error = -EBUSY;
 818                 swsusp_close(FMODE_READ);
 819                 goto Unlock;
 820         }
 821
 822         pm_prepare_console();
 823         error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
 824         if (error)
 825                 goto Close_Finish;
 826
 827         pr_debug("PM: Preparing processes for restore.\n");
 828         error = freeze_processes();
 829         if (error)
 830                 goto Close_Finish;
 831
 832         pr_debug("PM: Loading hibernation image.\n");
 833
 834         lock_device_hotplug();
 835         error = create_basic_memory_bitmaps();
 836         if (error)
 837                 goto Thaw;
 838
 839         error = swsusp_read(&flags);
 840         swsusp_close(FMODE_READ);
 841         if (!error)
 842                 hibernation_restore(flags & SF_PLATFORM_MODE);
 843
 844         printk(KERN_ERR "PM: Failed to load hibernation image, recovering.\n");
 845         swsusp_free();
 846         free_basic_memory_bitmaps();
 847  Thaw:
 848         unlock_device_hotplug();
 849         thaw_processes();
 850  Finish:
 851         pm_notifier_call_chain(PM_POST_RESTORE);
 852         pm_restore_console();
 853         atomic_inc(&snapshot_device_available);
 854         /* For success case, the suspend path will release the lock */
 855  Unlock:
 856         mutex_unlock(&pm_mutex);
 857         pr_debug("PM: Hibernation image not present or could not be loaded.\n");
 858         return error;
 859  Close_Finish:
 860         swsusp_close(FMODE_READ);
 861         goto Finish;
 862 }
 863
 864 late_initcall_sync(software_resume);
 865
 866
 867 static const char * const hibernation_modes[] = {
 868         [HIBERNATION_PLATFORM]  = "platform",
 869         [HIBERNATION_SHUTDOWN]  = "shutdown",
 870         [HIBERNATION_REBOOT]    = "reboot",
 871 #ifdef CONFIG_SUSPEND
 872         [HIBERNATION_SUSPEND]   = "suspend",
 873 #endif
 874 };
 875
 876 /*
 877  * /sys/power/disk - Control hibernation mode.
 878  *
 879  * Hibernation can be handled in several ways.  There are a few different ways
 880  * to put the system into the sleep state: using the platform driver (e.g. ACPI
 881  * or other hibernation_ops), powering it off or rebooting it (for testing
 882  * mostly).
 883  *
 884  * The sysfs file /sys/power/disk provides an interface for selecting the
 885  * hibernation mode to use.  Reading from this file causes the available modes
 886  * to be printed.  There are 3 modes that can be supported:
 887  *
 888  *      'platform'
 889  *      'shutdown'
 890  *      'reboot'
 891  *
 892  * If a platform hibernation driver is in use, 'platform' will be supported
 893  * and will be used by default.  Otherwise, 'shutdown' will be used by default.
 894  * The selected option (i.e. the one corresponding to the current value of
 895  * hibernation_mode) is enclosed by a square bracket.
 896  *
 897  * To select a given hibernation mode it is necessary to write the mode's
 898  * string representation (as returned by reading from /sys/power/disk) back
 899  * into /sys/power/disk.
 900  */
 901
 902 static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
 903                          char *buf)
 904 {
 905         int i;
 906         char *start = buf;
 907
 908         if (!hibernation_available())
 909                 return sprintf(buf, "[disabled]\n");
 910
 911         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 912                 if (!hibernation_modes[i])
 913                         continue;
 914                 switch (i) {
 915                 case HIBERNATION_SHUTDOWN:
 916                 case HIBERNATION_REBOOT:
 917 #ifdef CONFIG_SUSPEND
 918                 case HIBERNATION_SUSPEND:
 919 #endif
 920                         break;
 921                 case HIBERNATION_PLATFORM:
 922                         if (hibernation_ops)
 923                                 break;
 924                         /* not a valid mode, continue with loop */
 925                         continue;
 926                 }
 927                 if (i == hibernation_mode)
 928                         buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
 929                 else
 930                         buf += sprintf(buf, "%s ", hibernation_modes[i]);
 931         }
 932         buf += sprintf(buf, "\n");
 933         return buf-start;
 934 }
 935
 936 static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
 937                           const char *buf, size_t n)
 938 {
 939         int error = 0;
 940         int i;
 941         int len;
 942         char *p;
 943         int mode = HIBERNATION_INVALID;
 944
 945         if (!hibernation_available())
 946                 return -EPERM;
 947
 948         p = memchr(buf, '\n', n);
 949         len = p ? p - buf : n;
 950
 951         lock_system_sleep();
 952         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 953                 if (len == strlen(hibernation_modes[i])
 954                     && !strncmp(buf, hibernation_modes[i], len)) {
 955                         mode = i;
 956                         break;
 957                 }
 958         }
 959         if (mode != HIBERNATION_INVALID) {
 960                 switch (mode) {
 961                 case HIBERNATION_SHUTDOWN:
 962                 case HIBERNATION_REBOOT:
 963 #ifdef CONFIG_SUSPEND
 964                 case HIBERNATION_SUSPEND:
 965 #endif
 966                         hibernation_mode = mode;
 967                         break;
 968                 case HIBERNATION_PLATFORM:
 969                         if (hibernation_ops)
 970                                 hibernation_mode = mode;
 971                         else
 972                                 error = -EINVAL;
 973                 }
 974         } else
 975                 error = -EINVAL;
 976
 977         if (!error)
 978                 pr_debug("PM: Hibernation mode set to '%s'\n",
 979                          hibernation_modes[mode]);
 980         unlock_system_sleep();
 981         return error ? error : n;
 982 }
 983
 984 power_attr(disk);
 985
 986 static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
 987                            char *buf)
 988 {
 989         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
 990                        MINOR(swsusp_resume_device));
 991 }
 992
 993 static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
 994                             const char *buf, size_t n)
 995 {
 996         dev_t res;
 997         int len = n;
 998         char *name;
 999
1000         if (len && buf[len-1] == '\n')
1001                 len--;
1002         name = kstrndup(buf, len, GFP_KERNEL);
1003         if (!name)
1004                 return -ENOMEM;
1005
1006         res = name_to_dev_t(name);
1007         kfree(name);
1008         if (!res)
1009                 return -EINVAL;
1010
1011         lock_system_sleep();
1012         swsusp_resume_device = res;
1013         unlock_system_sleep();
1014         printk(KERN_INFO "PM: Starting manual resume from disk\n");
1015         noresume = 0;
1016         software_resume();
1017         return n;
1018 }
1019
1020 power_attr(resume);
1021
1022 static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
1023                                char *buf)
1024 {
1025         return sprintf(buf, "%lu\n", image_size);
1026 }
1027
1028 static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
1029                                 const char *buf, size_t n)
1030 {
1031         unsigned long size;
1032
1033         if (sscanf(buf, "%lu", &size) == 1) {
1034                 image_size = size;
1035                 return n;
1036         }
1037
1038         return -EINVAL;
1039 }
1040
1041 power_attr(image_size);
1042
1043 static ssize_t reserved_size_show(struct kobject *kobj,
1044                                   struct kobj_attribute *attr, char *buf)
1045 {
1046         return sprintf(buf, "%lu\n", reserved_size);
1047 }
1048
1049 static ssize_t reserved_size_store(struct kobject *kobj,
1050                                    struct kobj_attribute *attr,
1051                                    const char *buf, size_t n)
1052 {
1053         unsigned long size;
1054
1055         if (sscanf(buf, "%lu", &size) == 1) {
1056                 reserved_size = size;
1057                 return n;
1058         }
1059
1060         return -EINVAL;
1061 }
1062
1063 power_attr(reserved_size);
1064
1065 static struct attribute * g[] = {
1066         &disk_attr.attr,
1067         &resume_attr.attr,
1068         &image_size_attr.attr,
1069         &reserved_size_attr.attr,
1070         NULL,
1071 };
1072
1073
1074 static struct attribute_group attr_group = {
1075         .attrs = g,
1076 };
1077
1078
1079 static int __init pm_disk_init(void)
1080 {
1081         return sysfs_create_group(power_kobj, &attr_group);
1082 }
1083
1084 core_initcall(pm_disk_init);
1085
1086
1087 static int __init resume_setup(char *str)
1088 {
1089         if (noresume)
1090                 return 1;
1091
1092         strncpy( resume_file, str, 255 );
1093         return 1;
1094 }
1095
1096 static int __init resume_offset_setup(char *str)
1097 {
1098         unsigned long long offset;
1099
1100         if (noresume)
1101                 return 1;
1102
1103         if (sscanf(str, "%llu", &offset) == 1)
1104                 swsusp_resume_block = offset;
1105
1106         return 1;
1107 }
1108
1109 static int __init hibernate_setup(char *str)
1110 {
1111         if (!strncmp(str, "noresume", 8))
1112                 noresume = 1;
1113         else if (!strncmp(str, "nocompress", 10))
1114                 nocompress = 1;
1115         else if (!strncmp(str, "no", 2)) {
1116                 noresume = 1;
1117                 nohibernate = 1;
1118         }
1119         return 1;
1120 }
1121
1122 static int __init noresume_setup(char *str)
1123 {
1124         noresume = 1;
1125         return 1;
1126 }
1127
1128 static int __init resumewait_setup(char *str)
1129 {
1130         resume_wait = 1;
1131         return 1;
1132 }
1133
1134 static int __init resumedelay_setup(char *str)
1135 {
1136         int rc = kstrtouint(str, 0, &resume_delay);
1137
1138         if (rc)
1139                 return rc;
1140         return 1;
1141 }
1142
1143 static int __init nohibernate_setup(char *str)
1144 {
1145         noresume = 1;
1146         nohibernate = 1;
1147         return 1;
1148 }
1149
1150 static int __init kaslr_nohibernate_setup(char *str)
1151 {
1152         return nohibernate_setup(str);
1153 }
1154
1155 __setup("noresume", noresume_setup);
1156 __setup("resume_offset=", resume_offset_setup);
1157 __setup("resume=", resume_setup);
1158 __setup("hibernate=", hibernate_setup);
1159 __setup("resumewait", resumewait_setup);
1160 __setup("resumedelay=", resumedelay_setup);
1161 __setup("nohibernate", nohibernate_setup);
1162 __setup("kaslr", kaslr_nohibernate_setup);