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/nmi.h>
  25 #include <linux/console.h>
  26 #include <linux/cpu.h>
  27 #include <linux/freezer.h>
  28 #include <linux/gfp.h>
  29 #include <linux/syscore_ops.h>
  30 #include <linux/ctype.h>
  31 #include <linux/genhd.h>
  32 #include <linux/ktime.h>
  33 #include <trace/events/power.h>
  34
  35 #include "power.h"
  36
  37
  38 static int nocompress;
  39 static int noresume;
  40 static int nohibernate;
  41 static int resume_wait;
  42 static unsigned int resume_delay;
  43 static char resume_file[256] = CONFIG_PM_STD_PARTITION;
  44 dev_t swsusp_resume_device;
  45 sector_t swsusp_resume_block;
  46 __visible int in_suspend __nosavedata;
  47
  48 enum {
  49         HIBERNATION_INVALID,
  50         HIBERNATION_PLATFORM,
  51         HIBERNATION_SHUTDOWN,
  52         HIBERNATION_REBOOT,
  53 #ifdef CONFIG_SUSPEND
  54         HIBERNATION_SUSPEND,
  55 #endif
  56         HIBERNATION_TEST_RESUME,
  57         /* keep last */
  58         __HIBERNATION_AFTER_LAST
  59 };
  60 #define HIBERNATION_MAX (__HIBERNATION_AFTER_LAST-1)
  61 #define HIBERNATION_FIRST (HIBERNATION_INVALID + 1)
  62
  63 static int hibernation_mode = HIBERNATION_SHUTDOWN;
  64
  65 bool freezer_test_done;
  66
  67 static const struct platform_hibernation_ops *hibernation_ops;
  68
  69 bool hibernation_available(void)
  70 {
  71         return (nohibernate == 0);
  72 }
  73
  74 /**
  75  * hibernation_set_ops - Set the global hibernate operations.
  76  * @ops: Hibernation operations to use in subsequent hibernation transitions.
  77  */
  78 void hibernation_set_ops(const struct platform_hibernation_ops *ops)
  79 {
  80         if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
  81             && ops->prepare && ops->finish && ops->enter && ops->pre_restore
  82             && ops->restore_cleanup && ops->leave)) {
  83                 WARN_ON(1);
  84                 return;
  85         }
  86         lock_system_sleep();
  87         hibernation_ops = ops;
  88         if (ops)
  89                 hibernation_mode = HIBERNATION_PLATFORM;
  90         else if (hibernation_mode == HIBERNATION_PLATFORM)
  91                 hibernation_mode = HIBERNATION_SHUTDOWN;
  92
  93         unlock_system_sleep();
  94 }
  95 EXPORT_SYMBOL_GPL(hibernation_set_ops);
  96
  97 static bool entering_platform_hibernation;
  98
  99 bool system_entering_hibernation(void)
 100 {
 101         return entering_platform_hibernation;
 102 }
 103 EXPORT_SYMBOL(system_entering_hibernation);
 104
 105 #ifdef CONFIG_PM_DEBUG
 106 static void hibernation_debug_sleep(void)
 107 {
 108         printk(KERN_INFO "hibernation debug: Waiting for 5 seconds.\n");
 109         mdelay(5000);
 110 }
 111
 112 static int hibernation_test(int level)
 113 {
 114         if (pm_test_level == level) {
 115                 hibernation_debug_sleep();
 116                 return 1;
 117         }
 118         return 0;
 119 }
 120 #else /* !CONFIG_PM_DEBUG */
 121 static int hibernation_test(int level) { return 0; }
 122 #endif /* !CONFIG_PM_DEBUG */
 123
 124 /**
 125  * platform_begin - Call platform to start hibernation.
 126  * @platform_mode: Whether or not to use the platform driver.
 127  */
 128 static int platform_begin(int platform_mode)
 129 {
 130         return (platform_mode && hibernation_ops) ?
 131                 hibernation_ops->begin() : 0;
 132 }
 133
 134 /**
 135  * platform_end - Call platform to finish transition to the working state.
 136  * @platform_mode: Whether or not to use the platform driver.
 137  */
 138 static void platform_end(int platform_mode)
 139 {
 140         if (platform_mode && hibernation_ops)
 141                 hibernation_ops->end();
 142 }
 143
 144 /**
 145  * platform_pre_snapshot - Call platform to prepare the machine for hibernation.
 146  * @platform_mode: Whether or not to use the platform driver.
 147  *
 148  * Use the platform driver to prepare the system for creating a hibernate image,
 149  * if so configured, and return an error code if that fails.
 150  */
 151
 152 static int platform_pre_snapshot(int platform_mode)
 153 {
 154         return (platform_mode && hibernation_ops) ?
 155                 hibernation_ops->pre_snapshot() : 0;
 156 }
 157
 158 /**
 159  * platform_leave - Call platform to prepare a transition to the working state.
 160  * @platform_mode: Whether or not to use the platform driver.
 161  *
 162  * Use the platform driver prepare to prepare the machine for switching to the
 163  * normal mode of operation.
 164  *
 165  * This routine is called on one CPU with interrupts disabled.
 166  */
 167 static void platform_leave(int platform_mode)
 168 {
 169         if (platform_mode && hibernation_ops)
 170                 hibernation_ops->leave();
 171 }
 172
 173 /**
 174  * platform_finish - Call platform to switch the system to the working state.
 175  * @platform_mode: Whether or not to use the platform driver.
 176  *
 177  * Use the platform driver to switch the machine to the normal mode of
 178  * operation.
 179  *
 180  * This routine must be called after platform_prepare().
 181  */
 182 static void platform_finish(int platform_mode)
 183 {
 184         if (platform_mode && hibernation_ops)
 185                 hibernation_ops->finish();
 186 }
 187
 188 /**
 189  * platform_pre_restore - Prepare for hibernate image restoration.
 190  * @platform_mode: Whether or not to use the platform driver.
 191  *
 192  * Use the platform driver to prepare the system for resume from a hibernation
 193  * image.
 194  *
 195  * If the restore fails after this function has been called,
 196  * platform_restore_cleanup() must be called.
 197  */
 198 static int platform_pre_restore(int platform_mode)
 199 {
 200         return (platform_mode && hibernation_ops) ?
 201                 hibernation_ops->pre_restore() : 0;
 202 }
 203
 204 /**
 205  * platform_restore_cleanup - Switch to the working state after failing restore.
 206  * @platform_mode: Whether or not to use the platform driver.
 207  *
 208  * Use the platform driver to switch the system to the normal mode of operation
 209  * after a failing restore.
 210  *
 211  * If platform_pre_restore() has been called before the failing restore, this
 212  * function must be called too, regardless of the result of
 213  * platform_pre_restore().
 214  */
 215 static void platform_restore_cleanup(int platform_mode)
 216 {
 217         if (platform_mode && hibernation_ops)
 218                 hibernation_ops->restore_cleanup();
 219 }
 220
 221 /**
 222  * platform_recover - Recover from a failure to suspend devices.
 223  * @platform_mode: Whether or not to use the platform driver.
 224  */
 225 static void platform_recover(int platform_mode)
 226 {
 227         if (platform_mode && hibernation_ops && hibernation_ops->recover)
 228                 hibernation_ops->recover();
 229 }
 230
 231 /**
 232  * swsusp_show_speed - Print time elapsed between two events during hibernation.
 233  * @start: Starting event.
 234  * @stop: Final event.
 235  * @nr_pages: Number of memory pages processed between @start and @stop.
 236  * @msg: Additional diagnostic message to print.
 237  */
 238 void swsusp_show_speed(ktime_t start, ktime_t stop,
 239                       unsigned nr_pages, char *msg)
 240 {
 241         ktime_t diff;
 242         u64 elapsed_centisecs64;
 243         unsigned int centisecs;
 244         unsigned int k;
 245         unsigned int kps;
 246
 247         diff = ktime_sub(stop, start);
 248         elapsed_centisecs64 = ktime_divns(diff, 10*NSEC_PER_MSEC);
 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         /* Restore control flow magically appears here */
 305         restore_processor_state();
 306         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
 307         if (error)
 308                 printk(KERN_ERR "PM: Error %d creating hibernation image\n",
 309                         error);
 310         if (!in_suspend) {
 311                 events_check_enabled = false;
 312                 clear_free_pages();
 313         }
 314
 315         platform_leave(platform_mode);
 316
 317  Power_up:
 318         syscore_resume();
 319
 320  Enable_irqs:
 321         local_irq_enable();
 322
 323  Enable_cpus:
 324         enable_nonboot_cpus();
 325
 326  Platform_finish:
 327         platform_finish(platform_mode);
 328
 329         dpm_resume_start(in_suspend ?
 330                 (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
 331
 332         return error;
 333 }
 334
 335 /**
 336  * hibernation_snapshot - Quiesce devices and create a hibernation image.
 337  * @platform_mode: If set, use platform driver to prepare for the transition.
 338  *
 339  * This routine must be called with pm_mutex held.
 340  */
 341 int hibernation_snapshot(int platform_mode)
 342 {
 343         pm_message_t msg;
 344         int error;
 345
 346         pm_suspend_clear_flags();
 347         error = platform_begin(platform_mode);
 348         if (error)
 349                 goto Close;
 350
 351         /* Preallocate image memory before shutting down devices. */
 352         error = hibernate_preallocate_memory();
 353         if (error)
 354                 goto Close;
 355
 356         error = freeze_kernel_threads();
 357         if (error)
 358                 goto Cleanup;
 359
 360         if (hibernation_test(TEST_FREEZER)) {
 361
 362                 /*
 363                  * Indicate to the caller that we are returning due to a
 364                  * successful freezer test.
 365                  */
 366                 freezer_test_done = true;
 367                 goto Thaw;
 368         }
 369
 370         error = dpm_prepare(PMSG_FREEZE);
 371         if (error) {
 372                 dpm_complete(PMSG_RECOVER);
 373                 goto Thaw;
 374         }
 375
 376         suspend_console();
 377         pm_restrict_gfp_mask();
 378
 379         error = dpm_suspend(PMSG_FREEZE);
 380
 381         if (error || hibernation_test(TEST_DEVICES))
 382                 platform_recover(platform_mode);
 383         else
 384                 error = create_image(platform_mode);
 385
 386         /*
 387          * In the case that we call create_image() above, the control
 388          * returns here (1) after the image has been created or the
 389          * image creation has failed and (2) after a successful restore.
 390          */
 391
 392         /* We may need to release the preallocated image pages here. */
 393         if (error || !in_suspend)
 394                 swsusp_free();
 395
 396         msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
 397         dpm_resume(msg);
 398
 399         if (error || !in_suspend)
 400                 pm_restore_gfp_mask();
 401
 402         resume_console();
 403         dpm_complete(msg);
 404
 405  Close:
 406         platform_end(platform_mode);
 407         return error;
 408
 409  Thaw:
 410         thaw_kernel_threads();
 411  Cleanup:
 412         swsusp_free();
 413         goto Close;
 414 }
 415
 416 int __weak hibernate_resume_nonboot_cpu_disable(void)
 417 {
 418         return disable_nonboot_cpus();
 419 }
 420
 421 /**
 422  * resume_target_kernel - Restore system state from a hibernation image.
 423  * @platform_mode: Whether or not to use the platform driver.
 424  *
 425  * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
 426  * contents of highmem that have not been restored yet from the image and run
 427  * the low-level code that will restore the remaining contents of memory and
 428  * switch to the just restored target kernel.
 429  */
 430 static int resume_target_kernel(bool platform_mode)
 431 {
 432         int error;
 433
 434         error = dpm_suspend_end(PMSG_QUIESCE);
 435         if (error) {
 436                 printk(KERN_ERR "PM: Some devices failed to power down, "
 437                         "aborting resume\n");
 438                 return error;
 439         }
 440
 441         error = platform_pre_restore(platform_mode);
 442         if (error)
 443                 goto Cleanup;
 444
 445         error = hibernate_resume_nonboot_cpu_disable();
 446         if (error)
 447                 goto Enable_cpus;
 448
 449         local_irq_disable();
 450
 451         error = syscore_suspend();
 452         if (error)
 453                 goto Enable_irqs;
 454
 455         save_processor_state();
 456         error = restore_highmem();
 457         if (!error) {
 458                 error = swsusp_arch_resume();
 459                 /*
 460                  * The code below is only ever reached in case of a failure.
 461                  * Otherwise, execution continues at the place where
 462                  * swsusp_arch_suspend() was called.
 463                  */
 464                 BUG_ON(!error);
 465                 /*
 466                  * This call to restore_highmem() reverts the changes made by
 467                  * the previous one.
 468                  */
 469                 restore_highmem();
 470         }
 471         /*
 472          * The only reason why swsusp_arch_resume() can fail is memory being
 473          * very tight, so we have to free it as soon as we can to avoid
 474          * subsequent failures.
 475          */
 476         swsusp_free();
 477         restore_processor_state();
 478         touch_softlockup_watchdog();
 479
 480         syscore_resume();
 481
 482  Enable_irqs:
 483         local_irq_enable();
 484
 485  Enable_cpus:
 486         enable_nonboot_cpus();
 487
 488  Cleanup:
 489         platform_restore_cleanup(platform_mode);
 490
 491         dpm_resume_start(PMSG_RECOVER);
 492
 493         return error;
 494 }
 495
 496 /**
 497  * hibernation_restore - Quiesce devices and restore from a hibernation image.
 498  * @platform_mode: If set, use platform driver to prepare for the transition.
 499  *
 500  * This routine must be called with pm_mutex held.  If it is successful, control
 501  * reappears in the restored target kernel in hibernation_snapshot().
 502  */
 503 int hibernation_restore(int platform_mode)
 504 {
 505         int error;
 506
 507         pm_prepare_console();
 508         suspend_console();
 509         pm_restrict_gfp_mask();
 510         error = dpm_suspend_start(PMSG_QUIESCE);
 511         if (!error) {
 512                 error = resume_target_kernel(platform_mode);
 513                 /*
 514                  * The above should either succeed and jump to the new kernel,
 515                  * or return with an error. Otherwise things are just
 516                  * undefined, so let's be paranoid.
 517                  */
 518                 BUG_ON(!error);
 519         }
 520         dpm_resume_end(PMSG_RECOVER);
 521         pm_restore_gfp_mask();
 522         resume_console();
 523         pm_restore_console();
 524         return error;
 525 }
 526
 527 /**
 528  * hibernation_platform_enter - Power off the system using the platform driver.
 529  */
 530 int hibernation_platform_enter(void)
 531 {
 532         int error;
 533
 534         if (!hibernation_ops)
 535                 return -ENOSYS;
 536
 537         /*
 538          * We have cancelled the power transition by running
 539          * hibernation_ops->finish() before saving the image, so we should let
 540          * the firmware know that we're going to enter the sleep state after all
 541          */
 542         error = hibernation_ops->begin();
 543         if (error)
 544                 goto Close;
 545
 546         entering_platform_hibernation = true;
 547         suspend_console();
 548         error = dpm_suspend_start(PMSG_HIBERNATE);
 549         if (error) {
 550                 if (hibernation_ops->recover)
 551                         hibernation_ops->recover();
 552                 goto Resume_devices;
 553         }
 554
 555         error = dpm_suspend_end(PMSG_HIBERNATE);
 556         if (error)
 557                 goto Resume_devices;
 558
 559         error = hibernation_ops->prepare();
 560         if (error)
 561                 goto Platform_finish;
 562
 563         error = disable_nonboot_cpus();
 564         if (error)
 565                 goto Enable_cpus;
 566
 567         local_irq_disable();
 568         syscore_suspend();
 569         if (pm_wakeup_pending()) {
 570                 error = -EAGAIN;
 571                 goto Power_up;
 572         }
 573
 574         hibernation_ops->enter();
 575         /* We should never get here */
 576         while (1);
 577
 578  Power_up:
 579         syscore_resume();
 580         local_irq_enable();
 581
 582  Enable_cpus:
 583         enable_nonboot_cpus();
 584
 585  Platform_finish:
 586         hibernation_ops->finish();
 587
 588         dpm_resume_start(PMSG_RESTORE);
 589
 590  Resume_devices:
 591         entering_platform_hibernation = false;
 592         dpm_resume_end(PMSG_RESTORE);
 593         resume_console();
 594
 595  Close:
 596         hibernation_ops->end();
 597
 598         return error;
 599 }
 600
 601 /**
 602  * power_down - Shut the machine down for hibernation.
 603  *
 604  * Use the platform driver, if configured, to put the system into the sleep
 605  * state corresponding to hibernation, or try to power it off or reboot,
 606  * depending on the value of hibernation_mode.
 607  */
 608 static void power_down(void)
 609 {
 610 #ifdef CONFIG_SUSPEND
 611         int error;
 612 #endif
 613
 614         switch (hibernation_mode) {
 615         case HIBERNATION_REBOOT:
 616                 kernel_restart(NULL);
 617                 break;
 618         case HIBERNATION_PLATFORM:
 619                 hibernation_platform_enter();
 620         case HIBERNATION_SHUTDOWN:
 621                 if (pm_power_off)
 622                         kernel_power_off();
 623                 break;
 624 #ifdef CONFIG_SUSPEND
 625         case HIBERNATION_SUSPEND:
 626                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 627                 if (error) {
 628                         if (hibernation_ops)
 629                                 hibernation_mode = HIBERNATION_PLATFORM;
 630                         else
 631                                 hibernation_mode = HIBERNATION_SHUTDOWN;
 632                         power_down();
 633                 }
 634                 /*
 635                  * Restore swap signature.
 636                  */
 637                 error = swsusp_unmark();
 638                 if (error)
 639                         printk(KERN_ERR "PM: Swap will be unusable! "
 640                                         "Try swapon -a.\n");
 641                 return;
 642 #endif
 643         }
 644         kernel_halt();
 645         /*
 646          * Valid image is on the disk, if we continue we risk serious data
 647          * corruption after resume.
 648          */
 649         printk(KERN_CRIT "PM: Please power down manually\n");
 650         while (1)
 651                 cpu_relax();
 652 }
 653
 654 static int load_image_and_restore(void)
 655 {
 656         int error;
 657         unsigned int flags;
 658
 659         pr_debug("PM: Loading hibernation image.\n");
 660
 661         lock_device_hotplug();
 662         error = create_basic_memory_bitmaps();
 663         if (error)
 664                 goto Unlock;
 665
 666         error = swsusp_read(&flags);
 667         swsusp_close(FMODE_READ);
 668         if (!error)
 669                 hibernation_restore(flags & SF_PLATFORM_MODE);
 670
 671         printk(KERN_ERR "PM: Failed to load hibernation image, recovering.\n");
 672         swsusp_free();
 673         free_basic_memory_bitmaps();
 674  Unlock:
 675         unlock_device_hotplug();
 676
 677         return error;
 678 }
 679
 680 /**
 681  * hibernate - Carry out system hibernation, including saving the image.
 682  */
 683 int hibernate(void)
 684 {
 685         int error, nr_calls = 0;
 686         bool snapshot_test = false;
 687
 688         if (!hibernation_available()) {
 689                 pr_debug("PM: Hibernation not available.\n");
 690                 return -EPERM;
 691         }
 692
 693         lock_system_sleep();
 694         /* The snapshot device should not be opened while we're running */
 695         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 696                 error = -EBUSY;
 697                 goto Unlock;
 698         }
 699
 700         pm_prepare_console();
 701         error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls);
 702         if (error) {
 703                 nr_calls--;
 704                 goto Exit;
 705         }
 706
 707         printk(KERN_INFO "PM: Syncing filesystems ... ");
 708         sys_sync();
 709         printk("done.\n");
 710
 711         error = freeze_processes();
 712         if (error)
 713                 goto Exit;
 714
 715         lock_device_hotplug();
 716         /* Allocate memory management structures */
 717         error = create_basic_memory_bitmaps();
 718         if (error)
 719                 goto Thaw;
 720
 721         error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
 722         if (error || freezer_test_done)
 723                 goto Free_bitmaps;
 724
 725         if (in_suspend) {
 726                 unsigned int flags = 0;
 727
 728                 if (hibernation_mode == HIBERNATION_PLATFORM)
 729                         flags |= SF_PLATFORM_MODE;
 730                 if (nocompress)
 731                         flags |= SF_NOCOMPRESS_MODE;
 732                 else
 733                         flags |= SF_CRC32_MODE;
 734
 735                 pr_debug("PM: writing image.\n");
 736                 error = swsusp_write(flags);
 737                 swsusp_free();
 738                 if (!error) {
 739                         if (hibernation_mode == HIBERNATION_TEST_RESUME)
 740                                 snapshot_test = true;
 741                         else
 742                                 power_down();
 743                 }
 744                 in_suspend = 0;
 745                 pm_restore_gfp_mask();
 746         } else {
 747                 pr_debug("PM: Image restored successfully.\n");
 748         }
 749
 750  Free_bitmaps:
 751         free_basic_memory_bitmaps();
 752  Thaw:
 753         unlock_device_hotplug();
 754         if (snapshot_test) {
 755                 pr_debug("PM: Checking hibernation image\n");
 756                 error = swsusp_check();
 757                 if (!error)
 758                         error = load_image_and_restore();
 759         }
 760         thaw_processes();
 761
 762         /* Don't bother checking whether freezer_test_done is true */
 763         freezer_test_done = false;
 764  Exit:
 765         __pm_notifier_call_chain(PM_POST_HIBERNATION, nr_calls, NULL);
 766         pm_restore_console();
 767         atomic_inc(&snapshot_device_available);
 768  Unlock:
 769         unlock_system_sleep();
 770         return error;
 771 }
 772
 773
 774 /**
 775  * software_resume - Resume from a saved hibernation image.
 776  *
 777  * This routine is called as a late initcall, when all devices have been
 778  * discovered and initialized already.
 779  *
 780  * The image reading code is called to see if there is a hibernation image
 781  * available for reading.  If that is the case, devices are quiesced and the
 782  * contents of memory is restored from the saved image.
 783  *
 784  * If this is successful, control reappears in the restored target kernel in
 785  * hibernation_snapshot() which returns to hibernate().  Otherwise, the routine
 786  * attempts to recover gracefully and make the kernel return to the normal mode
 787  * of operation.
 788  */
 789 static int software_resume(void)
 790 {
 791         int error, nr_calls = 0;
 792
 793         /*
 794          * If the user said "noresume".. bail out early.
 795          */
 796         if (noresume || !hibernation_available())
 797                 return 0;
 798
 799         /*
 800          * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
 801          * is configured into the kernel. Since the regular hibernate
 802          * trigger path is via sysfs which takes a buffer mutex before
 803          * calling hibernate functions (which take pm_mutex) this can
 804          * cause lockdep to complain about a possible ABBA deadlock
 805          * which cannot happen since we're in the boot code here and
 806          * sysfs can't be invoked yet. Therefore, we use a subclass
 807          * here to avoid lockdep complaining.
 808          */
 809         mutex_lock_nested(&pm_mutex, SINGLE_DEPTH_NESTING);
 810
 811         if (swsusp_resume_device)
 812                 goto Check_image;
 813
 814         if (!strlen(resume_file)) {
 815                 error = -ENOENT;
 816                 goto Unlock;
 817         }
 818
 819         pr_debug("PM: Checking hibernation image partition %s\n", resume_file);
 820
 821         if (resume_delay) {
 822                 printk(KERN_INFO "Waiting %dsec before reading resume device...\n",
 823                         resume_delay);
 824                 ssleep(resume_delay);
 825         }
 826
 827         /* Check if the device is there */
 828         swsusp_resume_device = name_to_dev_t(resume_file);
 829
 830         /*
 831          * name_to_dev_t is ineffective to verify parition if resume_file is in
 832          * integer format. (e.g. major:minor)
 833          */
 834         if (isdigit(resume_file[0]) && resume_wait) {
 835                 int partno;
 836                 while (!get_gendisk(swsusp_resume_device, &partno))
 837                         msleep(10);
 838         }
 839
 840         if (!swsusp_resume_device) {
 841                 /*
 842                  * Some device discovery might still be in progress; we need
 843                  * to wait for this to finish.
 844                  */
 845                 wait_for_device_probe();
 846
 847                 if (resume_wait) {
 848                         while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
 849                                 msleep(10);
 850                         async_synchronize_full();
 851                 }
 852
 853                 swsusp_resume_device = name_to_dev_t(resume_file);
 854                 if (!swsusp_resume_device) {
 855                         error = -ENODEV;
 856                         goto Unlock;
 857                 }
 858         }
 859
 860  Check_image:
 861         pr_debug("PM: Hibernation image partition %d:%d present\n",
 862                 MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 863
 864         pr_debug("PM: Looking for hibernation image.\n");
 865         error = swsusp_check();
 866         if (error)
 867                 goto Unlock;
 868
 869         /* The snapshot device should not be opened while we're running */
 870         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 871                 error = -EBUSY;
 872                 swsusp_close(FMODE_READ);
 873                 goto Unlock;
 874         }
 875
 876         pm_prepare_console();
 877         error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls);
 878         if (error) {
 879                 nr_calls--;
 880                 goto Close_Finish;
 881         }
 882
 883         pr_debug("PM: Preparing processes for restore.\n");
 884         error = freeze_processes();
 885         if (error)
 886                 goto Close_Finish;
 887         error = load_image_and_restore();
 888         thaw_processes();
 889  Finish:
 890         __pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);
 891         pm_restore_console();
 892         atomic_inc(&snapshot_device_available);
 893         /* For success case, the suspend path will release the lock */
 894  Unlock:
 895         mutex_unlock(&pm_mutex);
 896         pr_debug("PM: Hibernation image not present or could not be loaded.\n");
 897         return error;
 898  Close_Finish:
 899         swsusp_close(FMODE_READ);
 900         goto Finish;
 901 }
 902
 903 late_initcall_sync(software_resume);
 904
 905
 906 static const char * const hibernation_modes[] = {
 907         [HIBERNATION_PLATFORM]  = "platform",
 908         [HIBERNATION_SHUTDOWN]  = "shutdown",
 909         [HIBERNATION_REBOOT]    = "reboot",
 910 #ifdef CONFIG_SUSPEND
 911         [HIBERNATION_SUSPEND]   = "suspend",
 912 #endif
 913         [HIBERNATION_TEST_RESUME]       = "test_resume",
 914 };
 915
 916 /*
 917  * /sys/power/disk - Control hibernation mode.
 918  *
 919  * Hibernation can be handled in several ways.  There are a few different ways
 920  * to put the system into the sleep state: using the platform driver (e.g. ACPI
 921  * or other hibernation_ops), powering it off or rebooting it (for testing
 922  * mostly).
 923  *
 924  * The sysfs file /sys/power/disk provides an interface for selecting the
 925  * hibernation mode to use.  Reading from this file causes the available modes
 926  * to be printed.  There are 3 modes that can be supported:
 927  *
 928  *      'platform'
 929  *      'shutdown'
 930  *      'reboot'
 931  *
 932  * If a platform hibernation driver is in use, 'platform' will be supported
 933  * and will be used by default.  Otherwise, 'shutdown' will be used by default.
 934  * The selected option (i.e. the one corresponding to the current value of
 935  * hibernation_mode) is enclosed by a square bracket.
 936  *
 937  * To select a given hibernation mode it is necessary to write the mode's
 938  * string representation (as returned by reading from /sys/power/disk) back
 939  * into /sys/power/disk.
 940  */
 941
 942 static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
 943                          char *buf)
 944 {
 945         int i;
 946         char *start = buf;
 947
 948         if (!hibernation_available())
 949                 return sprintf(buf, "[disabled]\n");
 950
 951         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 952                 if (!hibernation_modes[i])
 953                         continue;
 954                 switch (i) {
 955                 case HIBERNATION_SHUTDOWN:
 956                 case HIBERNATION_REBOOT:
 957 #ifdef CONFIG_SUSPEND
 958                 case HIBERNATION_SUSPEND:
 959 #endif
 960                 case HIBERNATION_TEST_RESUME:
 961                         break;
 962                 case HIBERNATION_PLATFORM:
 963                         if (hibernation_ops)
 964                                 break;
 965                         /* not a valid mode, continue with loop */
 966                         continue;
 967                 }
 968                 if (i == hibernation_mode)
 969                         buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
 970                 else
 971                         buf += sprintf(buf, "%s ", hibernation_modes[i]);
 972         }
 973         buf += sprintf(buf, "\n");
 974         return buf-start;
 975 }
 976
 977 static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
 978                           const char *buf, size_t n)
 979 {
 980         int error = 0;
 981         int i;
 982         int len;
 983         char *p;
 984         int mode = HIBERNATION_INVALID;
 985
 986         if (!hibernation_available())
 987                 return -EPERM;
 988
 989         p = memchr(buf, '\n', n);
 990         len = p ? p - buf : n;
 991
 992         lock_system_sleep();
 993         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 994                 if (len == strlen(hibernation_modes[i])
 995                     && !strncmp(buf, hibernation_modes[i], len)) {
 996                         mode = i;
 997                         break;
 998                 }
 999         }
1000         if (mode != HIBERNATION_INVALID) {
1001                 switch (mode) {
1002                 case HIBERNATION_SHUTDOWN:
1003                 case HIBERNATION_REBOOT:
1004 #ifdef CONFIG_SUSPEND
1005                 case HIBERNATION_SUSPEND:
1006 #endif
1007                 case HIBERNATION_TEST_RESUME:
1008                         hibernation_mode = mode;
1009                         break;
1010                 case HIBERNATION_PLATFORM:
1011                         if (hibernation_ops)
1012                                 hibernation_mode = mode;
1013                         else
1014                                 error = -EINVAL;
1015                 }
1016         } else
1017                 error = -EINVAL;
1018
1019         if (!error)
1020                 pr_debug("PM: Hibernation mode set to '%s'\n",
1021                          hibernation_modes[mode]);
1022         unlock_system_sleep();
1023         return error ? error : n;
1024 }
1025
1026 power_attr(disk);
1027
1028 static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
1029                            char *buf)
1030 {
1031         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
1032                        MINOR(swsusp_resume_device));
1033 }
1034
1035 static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
1036                             const char *buf, size_t n)
1037 {
1038         dev_t res;
1039         int len = n;
1040         char *name;
1041
1042         if (len && buf[len-1] == '\n')
1043                 len--;
1044         name = kstrndup(buf, len, GFP_KERNEL);
1045         if (!name)
1046                 return -ENOMEM;
1047
1048         res = name_to_dev_t(name);
1049         kfree(name);
1050         if (!res)
1051                 return -EINVAL;
1052
1053         lock_system_sleep();
1054         swsusp_resume_device = res;
1055         unlock_system_sleep();
1056         printk(KERN_INFO "PM: Starting manual resume from disk\n");
1057         noresume = 0;
1058         software_resume();
1059         return n;
1060 }
1061
1062 power_attr(resume);
1063
1064 static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
1065                                char *buf)
1066 {
1067         return sprintf(buf, "%lu\n", image_size);
1068 }
1069
1070 static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
1071                                 const char *buf, size_t n)
1072 {
1073         unsigned long size;
1074
1075         if (sscanf(buf, "%lu", &size) == 1) {
1076                 image_size = size;
1077                 return n;
1078         }
1079
1080         return -EINVAL;
1081 }
1082
1083 power_attr(image_size);
1084
1085 static ssize_t reserved_size_show(struct kobject *kobj,
1086                                   struct kobj_attribute *attr, char *buf)
1087 {
1088         return sprintf(buf, "%lu\n", reserved_size);
1089 }
1090
1091 static ssize_t reserved_size_store(struct kobject *kobj,
1092                                    struct kobj_attribute *attr,
1093                                    const char *buf, size_t n)
1094 {
1095         unsigned long size;
1096
1097         if (sscanf(buf, "%lu", &size) == 1) {
1098                 reserved_size = size;
1099                 return n;
1100         }
1101
1102         return -EINVAL;
1103 }
1104
1105 power_attr(reserved_size);
1106
1107 static struct attribute * g[] = {
1108         &disk_attr.attr,
1109         &resume_attr.attr,
1110         &image_size_attr.attr,
1111         &reserved_size_attr.attr,
1112         NULL,
1113 };
1114
1115
1116 static struct attribute_group attr_group = {
1117         .attrs = g,
1118 };
1119
1120
1121 static int __init pm_disk_init(void)
1122 {
1123         return sysfs_create_group(power_kobj, &attr_group);
1124 }
1125
1126 core_initcall(pm_disk_init);
1127
1128
1129 static int __init resume_setup(char *str)
1130 {
1131         if (noresume)
1132                 return 1;
1133
1134         strncpy( resume_file, str, 255 );
1135         return 1;
1136 }
1137
1138 static int __init resume_offset_setup(char *str)
1139 {
1140         unsigned long long offset;
1141
1142         if (noresume)
1143                 return 1;
1144
1145         if (sscanf(str, "%llu", &offset) == 1)
1146                 swsusp_resume_block = offset;
1147
1148         return 1;
1149 }
1150
1151 static int __init hibernate_setup(char *str)
1152 {
1153         if (!strncmp(str, "noresume", 8)) {
1154                 noresume = 1;
1155         } else if (!strncmp(str, "nocompress", 10)) {
1156                 nocompress = 1;
1157         } else if (!strncmp(str, "no", 2)) {
1158                 noresume = 1;
1159                 nohibernate = 1;
1160         } else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)
1161                    && !strncmp(str, "protect_image", 13)) {
1162                 enable_restore_image_protection();
1163         }
1164         return 1;
1165 }
1166
1167 static int __init noresume_setup(char *str)
1168 {
1169         noresume = 1;
1170         return 1;
1171 }
1172
1173 static int __init resumewait_setup(char *str)
1174 {
1175         resume_wait = 1;
1176         return 1;
1177 }
1178
1179 static int __init resumedelay_setup(char *str)
1180 {
1181         int rc = kstrtouint(str, 0, &resume_delay);
1182
1183         if (rc)
1184                 return rc;
1185         return 1;
1186 }
1187
1188 static int __init nohibernate_setup(char *str)
1189 {
1190         noresume = 1;
1191         nohibernate = 1;
1192         return 1;
1193 }
1194
1195 __setup("noresume", noresume_setup);
1196 __setup("resume_offset=", resume_offset_setup);
1197 __setup("resume=", resume_setup);
1198 __setup("hibernate=", hibernate_setup);
1199 __setup("resumewait", resumewait_setup);
1200 __setup("resumedelay=", resumedelay_setup);
1201 __setup("nohibernate", nohibernate_setup);