kernel/power/hibernate.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * kernel/power/hibernate.c - Hibernation (a.k.a suspend-to-disk) support.
   4  *
   5  * Copyright (c) 2003 Patrick Mochel
   6  * Copyright (c) 2003 Open Source Development Lab
   7  * Copyright (c) 2004 Pavel Machek <pavel@ucw.cz>
   8  * Copyright (c) 2009 Rafael J. Wysocki, Novell Inc.
   9  * Copyright (C) 2012 Bojan Smojver <bojan@rexursive.com>
  10  */
  11
  12 #define pr_fmt(fmt) "PM: hibernation: " fmt
  13
  14 #include <linux/export.h>
  15 #include <linux/suspend.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 <linux/security.h>
  34 #include <trace/events/power.h>
  35
  36 #include "power.h"
  37
  38
  39 static int nocompress;
  40 static int noresume;
  41 static int nohibernate;
  42 static int resume_wait;
  43 static unsigned int resume_delay;
  44 static char resume_file[256] = CONFIG_PM_STD_PARTITION;
  45 dev_t swsusp_resume_device;
  46 sector_t swsusp_resume_block;
  47 __visible int in_suspend __nosavedata;
  48
  49 enum {
  50         HIBERNATION_INVALID,
  51         HIBERNATION_PLATFORM,
  52         HIBERNATION_SHUTDOWN,
  53         HIBERNATION_REBOOT,
  54 #ifdef CONFIG_SUSPEND
  55         HIBERNATION_SUSPEND,
  56 #endif
  57         HIBERNATION_TEST_RESUME,
  58         /* keep last */
  59         __HIBERNATION_AFTER_LAST
  60 };
  61 #define HIBERNATION_MAX (__HIBERNATION_AFTER_LAST-1)
  62 #define HIBERNATION_FIRST (HIBERNATION_INVALID + 1)
  63
  64 static int hibernation_mode = HIBERNATION_SHUTDOWN;
  65
  66 bool freezer_test_done;
  67
  68 static const struct platform_hibernation_ops *hibernation_ops;
  69
  70 bool hibernation_available(void)
  71 {
  72         return nohibernate == 0 && !security_locked_down(LOCKDOWN_HIBERNATION);
  73 }
  74
  75 /**
  76  * hibernation_set_ops - Set the global hibernate operations.
  77  * @ops: Hibernation operations to use in subsequent hibernation transitions.
  78  */
  79 void hibernation_set_ops(const struct platform_hibernation_ops *ops)
  80 {
  81         if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
  82             && ops->prepare && ops->finish && ops->enter && ops->pre_restore
  83             && ops->restore_cleanup && ops->leave)) {
  84                 WARN_ON(1);
  85                 return;
  86         }
  87         lock_system_sleep();
  88         hibernation_ops = ops;
  89         if (ops)
  90                 hibernation_mode = HIBERNATION_PLATFORM;
  91         else if (hibernation_mode == HIBERNATION_PLATFORM)
  92                 hibernation_mode = HIBERNATION_SHUTDOWN;
  93
  94         unlock_system_sleep();
  95 }
  96 EXPORT_SYMBOL_GPL(hibernation_set_ops);
  97
  98 static bool entering_platform_hibernation;
  99
 100 bool system_entering_hibernation(void)
 101 {
 102         return entering_platform_hibernation;
 103 }
 104 EXPORT_SYMBOL(system_entering_hibernation);
 105
 106 #ifdef CONFIG_PM_DEBUG
 107 static void hibernation_debug_sleep(void)
 108 {
 109         pr_info("debug: Waiting for 5 seconds.\n");
 110         mdelay(5000);
 111 }
 112
 113 static int hibernation_test(int level)
 114 {
 115         if (pm_test_level == level) {
 116                 hibernation_debug_sleep();
 117                 return 1;
 118         }
 119         return 0;
 120 }
 121 #else /* !CONFIG_PM_DEBUG */
 122 static int hibernation_test(int level) { return 0; }
 123 #endif /* !CONFIG_PM_DEBUG */
 124
 125 /**
 126  * platform_begin - Call platform to start hibernation.
 127  * @platform_mode: Whether or not to use the platform driver.
 128  */
 129 static int platform_begin(int platform_mode)
 130 {
 131         return (platform_mode && hibernation_ops) ?
 132                 hibernation_ops->begin(PMSG_FREEZE) : 0;
 133 }
 134
 135 /**
 136  * platform_end - Call platform to finish transition to the working state.
 137  * @platform_mode: Whether or not to use the platform driver.
 138  */
 139 static void platform_end(int platform_mode)
 140 {
 141         if (platform_mode && hibernation_ops)
 142                 hibernation_ops->end();
 143 }
 144
 145 /**
 146  * platform_pre_snapshot - Call platform to prepare the machine for hibernation.
 147  * @platform_mode: Whether or not to use the platform driver.
 148  *
 149  * Use the platform driver to prepare the system for creating a hibernate image,
 150  * if so configured, and return an error code if that fails.
 151  */
 152
 153 static int platform_pre_snapshot(int platform_mode)
 154 {
 155         return (platform_mode && hibernation_ops) ?
 156                 hibernation_ops->pre_snapshot() : 0;
 157 }
 158
 159 /**
 160  * platform_leave - Call platform to prepare a transition to the working state.
 161  * @platform_mode: Whether or not to use the platform driver.
 162  *
 163  * Use the platform driver prepare to prepare the machine for switching to the
 164  * normal mode of operation.
 165  *
 166  * This routine is called on one CPU with interrupts disabled.
 167  */
 168 static void platform_leave(int platform_mode)
 169 {
 170         if (platform_mode && hibernation_ops)
 171                 hibernation_ops->leave();
 172 }
 173
 174 /**
 175  * platform_finish - Call platform to switch the system to the working state.
 176  * @platform_mode: Whether or not to use the platform driver.
 177  *
 178  * Use the platform driver to switch the machine to the normal mode of
 179  * operation.
 180  *
 181  * This routine must be called after platform_prepare().
 182  */
 183 static void platform_finish(int platform_mode)
 184 {
 185         if (platform_mode && hibernation_ops)
 186                 hibernation_ops->finish();
 187 }
 188
 189 /**
 190  * platform_pre_restore - Prepare for hibernate image restoration.
 191  * @platform_mode: Whether or not to use the platform driver.
 192  *
 193  * Use the platform driver to prepare the system for resume from a hibernation
 194  * image.
 195  *
 196  * If the restore fails after this function has been called,
 197  * platform_restore_cleanup() must be called.
 198  */
 199 static int platform_pre_restore(int platform_mode)
 200 {
 201         return (platform_mode && hibernation_ops) ?
 202                 hibernation_ops->pre_restore() : 0;
 203 }
 204
 205 /**
 206  * platform_restore_cleanup - Switch to the working state after failing restore.
 207  * @platform_mode: Whether or not to use the platform driver.
 208  *
 209  * Use the platform driver to switch the system to the normal mode of operation
 210  * after a failing restore.
 211  *
 212  * If platform_pre_restore() has been called before the failing restore, this
 213  * function must be called too, regardless of the result of
 214  * platform_pre_restore().
 215  */
 216 static void platform_restore_cleanup(int platform_mode)
 217 {
 218         if (platform_mode && hibernation_ops)
 219                 hibernation_ops->restore_cleanup();
 220 }
 221
 222 /**
 223  * platform_recover - Recover from a failure to suspend devices.
 224  * @platform_mode: Whether or not to use the platform driver.
 225  */
 226 static void platform_recover(int platform_mode)
 227 {
 228         if (platform_mode && hibernation_ops && hibernation_ops->recover)
 229                 hibernation_ops->recover();
 230 }
 231
 232 /**
 233  * swsusp_show_speed - Print time elapsed between two events during hibernation.
 234  * @start: Starting event.
 235  * @stop: Final event.
 236  * @nr_pages: Number of memory pages processed between @start and @stop.
 237  * @msg: Additional diagnostic message to print.
 238  */
 239 void swsusp_show_speed(ktime_t start, ktime_t stop,
 240                       unsigned nr_pages, char *msg)
 241 {
 242         ktime_t diff;
 243         u64 elapsed_centisecs64;
 244         unsigned int centisecs;
 245         unsigned int k;
 246         unsigned int kps;
 247
 248         diff = ktime_sub(stop, start);
 249         elapsed_centisecs64 = ktime_divns(diff, 10*NSEC_PER_MSEC);
 250         centisecs = elapsed_centisecs64;
 251         if (centisecs == 0)
 252                 centisecs = 1;  /* avoid div-by-zero */
 253         k = nr_pages * (PAGE_SIZE / 1024);
 254         kps = (k * 100) / centisecs;
 255         pr_info("%s %u kbytes in %u.%02u seconds (%u.%02u MB/s)\n",
 256                 msg, k, centisecs / 100, centisecs % 100, kps / 1000,
 257                 (kps % 1000) / 10);
 258 }
 259
 260 __weak int arch_resume_nosmt(void)
 261 {
 262         return 0;
 263 }
 264
 265 /**
 266  * create_image - Create a hibernation image.
 267  * @platform_mode: Whether or not to use the platform driver.
 268  *
 269  * Execute device drivers' "late" and "noirq" freeze callbacks, create a
 270  * hibernation image and run the drivers' "noirq" and "early" thaw callbacks.
 271  *
 272  * Control reappears in this routine after the subsequent restore.
 273  */
 274 static int create_image(int platform_mode)
 275 {
 276         int error;
 277
 278         error = dpm_suspend_end(PMSG_FREEZE);
 279         if (error) {
 280                 pr_err("Some devices failed to power down, aborting\n");
 281                 return error;
 282         }
 283
 284         error = platform_pre_snapshot(platform_mode);
 285         if (error || hibernation_test(TEST_PLATFORM))
 286                 goto Platform_finish;
 287
 288         error = suspend_disable_secondary_cpus();
 289         if (error || hibernation_test(TEST_CPUS))
 290                 goto Enable_cpus;
 291
 292         local_irq_disable();
 293
 294         system_state = SYSTEM_SUSPEND;
 295
 296         error = syscore_suspend();
 297         if (error) {
 298                 pr_err("Some system devices failed to power down, aborting\n");
 299                 goto Enable_irqs;
 300         }
 301
 302         if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
 303                 goto Power_up;
 304
 305         in_suspend = 1;
 306         save_processor_state();
 307         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);
 308         error = swsusp_arch_suspend();
 309         /* Restore control flow magically appears here */
 310         restore_processor_state();
 311         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
 312         if (error)
 313                 pr_err("Error %d creating image\n", error);
 314
 315         if (!in_suspend) {
 316                 events_check_enabled = false;
 317                 clear_free_pages();
 318         }
 319
 320         platform_leave(platform_mode);
 321
 322  Power_up:
 323         syscore_resume();
 324
 325  Enable_irqs:
 326         system_state = SYSTEM_RUNNING;
 327         local_irq_enable();
 328
 329  Enable_cpus:
 330         suspend_enable_secondary_cpus();
 331
 332         /* Allow architectures to do nosmt-specific post-resume dances */
 333         if (!in_suspend)
 334                 error = arch_resume_nosmt();
 335
 336  Platform_finish:
 337         platform_finish(platform_mode);
 338
 339         dpm_resume_start(in_suspend ?
 340                 (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
 341
 342         return error;
 343 }
 344
 345 /**
 346  * hibernation_snapshot - Quiesce devices and create a hibernation image.
 347  * @platform_mode: If set, use platform driver to prepare for the transition.
 348  *
 349  * This routine must be called with system_transition_mutex held.
 350  */
 351 int hibernation_snapshot(int platform_mode)
 352 {
 353         pm_message_t msg;
 354         int error;
 355
 356         pm_suspend_clear_flags();
 357         error = platform_begin(platform_mode);
 358         if (error)
 359                 goto Close;
 360
 361         /* Preallocate image memory before shutting down devices. */
 362         error = hibernate_preallocate_memory();
 363         if (error)
 364                 goto Close;
 365
 366         error = freeze_kernel_threads();
 367         if (error)
 368                 goto Cleanup;
 369
 370         if (hibernation_test(TEST_FREEZER)) {
 371
 372                 /*
 373                  * Indicate to the caller that we are returning due to a
 374                  * successful freezer test.
 375                  */
 376                 freezer_test_done = true;
 377                 goto Thaw;
 378         }
 379
 380         error = dpm_prepare(PMSG_FREEZE);
 381         if (error) {
 382                 dpm_complete(PMSG_RECOVER);
 383                 goto Thaw;
 384         }
 385
 386         suspend_console();
 387         pm_restrict_gfp_mask();
 388
 389         error = dpm_suspend(PMSG_FREEZE);
 390
 391         if (error || hibernation_test(TEST_DEVICES))
 392                 platform_recover(platform_mode);
 393         else
 394                 error = create_image(platform_mode);
 395
 396         /*
 397          * In the case that we call create_image() above, the control
 398          * returns here (1) after the image has been created or the
 399          * image creation has failed and (2) after a successful restore.
 400          */
 401
 402         /* We may need to release the preallocated image pages here. */
 403         if (error || !in_suspend)
 404                 swsusp_free();
 405
 406         msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
 407         dpm_resume(msg);
 408
 409         if (error || !in_suspend)
 410                 pm_restore_gfp_mask();
 411
 412         resume_console();
 413         dpm_complete(msg);
 414
 415  Close:
 416         platform_end(platform_mode);
 417         return error;
 418
 419  Thaw:
 420         thaw_kernel_threads();
 421  Cleanup:
 422         swsusp_free();
 423         goto Close;
 424 }
 425
 426 int __weak hibernate_resume_nonboot_cpu_disable(void)
 427 {
 428         return suspend_disable_secondary_cpus();
 429 }
 430
 431 /**
 432  * resume_target_kernel - Restore system state from a hibernation image.
 433  * @platform_mode: Whether or not to use the platform driver.
 434  *
 435  * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
 436  * contents of highmem that have not been restored yet from the image and run
 437  * the low-level code that will restore the remaining contents of memory and
 438  * switch to the just restored target kernel.
 439  */
 440 static int resume_target_kernel(bool platform_mode)
 441 {
 442         int error;
 443
 444         error = dpm_suspend_end(PMSG_QUIESCE);
 445         if (error) {
 446                 pr_err("Some devices failed to power down, aborting resume\n");
 447                 return error;
 448         }
 449
 450         error = platform_pre_restore(platform_mode);
 451         if (error)
 452                 goto Cleanup;
 453
 454         error = hibernate_resume_nonboot_cpu_disable();
 455         if (error)
 456                 goto Enable_cpus;
 457
 458         local_irq_disable();
 459         system_state = SYSTEM_SUSPEND;
 460
 461         error = syscore_suspend();
 462         if (error)
 463                 goto Enable_irqs;
 464
 465         save_processor_state();
 466         error = restore_highmem();
 467         if (!error) {
 468                 error = swsusp_arch_resume();
 469                 /*
 470                  * The code below is only ever reached in case of a failure.
 471                  * Otherwise, execution continues at the place where
 472                  * swsusp_arch_suspend() was called.
 473                  */
 474                 BUG_ON(!error);
 475                 /*
 476                  * This call to restore_highmem() reverts the changes made by
 477                  * the previous one.
 478                  */
 479                 restore_highmem();
 480         }
 481         /*
 482          * The only reason why swsusp_arch_resume() can fail is memory being
 483          * very tight, so we have to free it as soon as we can to avoid
 484          * subsequent failures.
 485          */
 486         swsusp_free();
 487         restore_processor_state();
 488         touch_softlockup_watchdog();
 489
 490         syscore_resume();
 491
 492  Enable_irqs:
 493         system_state = SYSTEM_RUNNING;
 494         local_irq_enable();
 495
 496  Enable_cpus:
 497         suspend_enable_secondary_cpus();
 498
 499  Cleanup:
 500         platform_restore_cleanup(platform_mode);
 501
 502         dpm_resume_start(PMSG_RECOVER);
 503
 504         return error;
 505 }
 506
 507 /**
 508  * hibernation_restore - Quiesce devices and restore from a hibernation image.
 509  * @platform_mode: If set, use platform driver to prepare for the transition.
 510  *
 511  * This routine must be called with system_transition_mutex held.  If it is
 512  * successful, control reappears in the restored target kernel in
 513  * hibernation_snapshot().
 514  */
 515 int hibernation_restore(int platform_mode)
 516 {
 517         int error;
 518
 519         pm_prepare_console();
 520         suspend_console();
 521         pm_restrict_gfp_mask();
 522         error = dpm_suspend_start(PMSG_QUIESCE);
 523         if (!error) {
 524                 error = resume_target_kernel(platform_mode);
 525                 /*
 526                  * The above should either succeed and jump to the new kernel,
 527                  * or return with an error. Otherwise things are just
 528                  * undefined, so let's be paranoid.
 529                  */
 530                 BUG_ON(!error);
 531         }
 532         dpm_resume_end(PMSG_RECOVER);
 533         pm_restore_gfp_mask();
 534         resume_console();
 535         pm_restore_console();
 536         return error;
 537 }
 538
 539 /**
 540  * hibernation_platform_enter - Power off the system using the platform driver.
 541  */
 542 int hibernation_platform_enter(void)
 543 {
 544         int error;
 545
 546         if (!hibernation_ops)
 547                 return -ENOSYS;
 548
 549         /*
 550          * We have cancelled the power transition by running
 551          * hibernation_ops->finish() before saving the image, so we should let
 552          * the firmware know that we're going to enter the sleep state after all
 553          */
 554         error = hibernation_ops->begin(PMSG_HIBERNATE);
 555         if (error)
 556                 goto Close;
 557
 558         entering_platform_hibernation = true;
 559         suspend_console();
 560         error = dpm_suspend_start(PMSG_HIBERNATE);
 561         if (error) {
 562                 if (hibernation_ops->recover)
 563                         hibernation_ops->recover();
 564                 goto Resume_devices;
 565         }
 566
 567         error = dpm_suspend_end(PMSG_HIBERNATE);
 568         if (error)
 569                 goto Resume_devices;
 570
 571         error = hibernation_ops->prepare();
 572         if (error)
 573                 goto Platform_finish;
 574
 575         error = suspend_disable_secondary_cpus();
 576         if (error)
 577                 goto Enable_cpus;
 578
 579         local_irq_disable();
 580         system_state = SYSTEM_SUSPEND;
 581         syscore_suspend();
 582         if (pm_wakeup_pending()) {
 583                 error = -EAGAIN;
 584                 goto Power_up;
 585         }
 586
 587         hibernation_ops->enter();
 588         /* We should never get here */
 589         while (1);
 590
 591  Power_up:
 592         syscore_resume();
 593         system_state = SYSTEM_RUNNING;
 594         local_irq_enable();
 595
 596  Enable_cpus:
 597         suspend_enable_secondary_cpus();
 598
 599  Platform_finish:
 600         hibernation_ops->finish();
 601
 602         dpm_resume_start(PMSG_RESTORE);
 603
 604  Resume_devices:
 605         entering_platform_hibernation = false;
 606         dpm_resume_end(PMSG_RESTORE);
 607         resume_console();
 608
 609  Close:
 610         hibernation_ops->end();
 611
 612         return error;
 613 }
 614
 615 /**
 616  * power_down - Shut the machine down for hibernation.
 617  *
 618  * Use the platform driver, if configured, to put the system into the sleep
 619  * state corresponding to hibernation, or try to power it off or reboot,
 620  * depending on the value of hibernation_mode.
 621  */
 622 static void power_down(void)
 623 {
 624 #ifdef CONFIG_SUSPEND
 625         int error;
 626
 627         if (hibernation_mode == HIBERNATION_SUSPEND) {
 628                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 629                 if (error) {
 630                         hibernation_mode = hibernation_ops ?
 631                                                 HIBERNATION_PLATFORM :
 632                                                 HIBERNATION_SHUTDOWN;
 633                 } else {
 634                         /* Restore swap signature. */
 635                         error = swsusp_unmark();
 636                         if (error)
 637                                 pr_err("Swap will be unusable! Try swapon -a.\n");
 638
 639                         return;
 640                 }
 641         }
 642 #endif
 643
 644         switch (hibernation_mode) {
 645         case HIBERNATION_REBOOT:
 646                 kernel_restart(NULL);
 647                 break;
 648         case HIBERNATION_PLATFORM:
 649                 hibernation_platform_enter();
 650                 /* Fall through */
 651         case HIBERNATION_SHUTDOWN:
 652                 if (pm_power_off)
 653                         kernel_power_off();
 654                 break;
 655         }
 656         kernel_halt();
 657         /*
 658          * Valid image is on the disk, if we continue we risk serious data
 659          * corruption after resume.
 660          */
 661         pr_crit("Power down manually\n");
 662         while (1)
 663                 cpu_relax();
 664 }
 665
 666 static int load_image_and_restore(void)
 667 {
 668         int error;
 669         unsigned int flags;
 670
 671         pm_pr_dbg("Loading hibernation image.\n");
 672
 673         lock_device_hotplug();
 674         error = create_basic_memory_bitmaps();
 675         if (error)
 676                 goto Unlock;
 677
 678         error = swsusp_read(&flags);
 679         swsusp_close(FMODE_READ);
 680         if (!error)
 681                 error = hibernation_restore(flags & SF_PLATFORM_MODE);
 682
 683         pr_err("Failed to load image, recovering.\n");
 684         swsusp_free();
 685         free_basic_memory_bitmaps();
 686  Unlock:
 687         unlock_device_hotplug();
 688
 689         return error;
 690 }
 691
 692 /**
 693  * hibernate - Carry out system hibernation, including saving the image.
 694  */
 695 int hibernate(void)
 696 {
 697         int error, nr_calls = 0;
 698         bool snapshot_test = false;
 699
 700         if (!hibernation_available()) {
 701                 pm_pr_dbg("Hibernation not available.\n");
 702                 return -EPERM;
 703         }
 704
 705         lock_system_sleep();
 706         /* The snapshot device should not be opened while we're running */
 707         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 708                 error = -EBUSY;
 709                 goto Unlock;
 710         }
 711
 712         pr_info("hibernation entry\n");
 713         pm_prepare_console();
 714         error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls);
 715         if (error) {
 716                 nr_calls--;
 717                 goto Exit;
 718         }
 719
 720         ksys_sync_helper();
 721
 722         error = freeze_processes();
 723         if (error)
 724                 goto Exit;
 725
 726         lock_device_hotplug();
 727         /* Allocate memory management structures */
 728         error = create_basic_memory_bitmaps();
 729         if (error)
 730                 goto Thaw;
 731
 732         error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
 733         if (error || freezer_test_done)
 734                 goto Free_bitmaps;
 735
 736         if (in_suspend) {
 737                 unsigned int flags = 0;
 738
 739                 if (hibernation_mode == HIBERNATION_PLATFORM)
 740                         flags |= SF_PLATFORM_MODE;
 741                 if (nocompress)
 742                         flags |= SF_NOCOMPRESS_MODE;
 743                 else
 744                         flags |= SF_CRC32_MODE;
 745
 746                 pm_pr_dbg("Writing hibernation image.\n");
 747                 error = swsusp_write(flags);
 748                 swsusp_free();
 749                 if (!error) {
 750                         if (hibernation_mode == HIBERNATION_TEST_RESUME)
 751                                 snapshot_test = true;
 752                         else
 753                                 power_down();
 754                 }
 755                 in_suspend = 0;
 756                 pm_restore_gfp_mask();
 757         } else {
 758                 pm_pr_dbg("Hibernation image restored successfully.\n");
 759         }
 760
 761  Free_bitmaps:
 762         free_basic_memory_bitmaps();
 763  Thaw:
 764         unlock_device_hotplug();
 765         if (snapshot_test) {
 766                 pm_pr_dbg("Checking hibernation image\n");
 767                 error = swsusp_check();
 768                 if (!error)
 769                         error = load_image_and_restore();
 770         }
 771         thaw_processes();
 772
 773         /* Don't bother checking whether freezer_test_done is true */
 774         freezer_test_done = false;
 775  Exit:
 776         __pm_notifier_call_chain(PM_POST_HIBERNATION, nr_calls, NULL);
 777         pm_restore_console();
 778         atomic_inc(&snapshot_device_available);
 779  Unlock:
 780         unlock_system_sleep();
 781         pr_info("hibernation exit\n");
 782
 783         return error;
 784 }
 785
 786
 787 /**
 788  * software_resume - Resume from a saved hibernation image.
 789  *
 790  * This routine is called as a late initcall, when all devices have been
 791  * discovered and initialized already.
 792  *
 793  * The image reading code is called to see if there is a hibernation image
 794  * available for reading.  If that is the case, devices are quiesced and the
 795  * contents of memory is restored from the saved image.
 796  *
 797  * If this is successful, control reappears in the restored target kernel in
 798  * hibernation_snapshot() which returns to hibernate().  Otherwise, the routine
 799  * attempts to recover gracefully and make the kernel return to the normal mode
 800  * of operation.
 801  */
 802 static int software_resume(void)
 803 {
 804         int error, nr_calls = 0;
 805
 806         /*
 807          * If the user said "noresume".. bail out early.
 808          */
 809         if (noresume || !hibernation_available())
 810                 return 0;
 811
 812         /*
 813          * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
 814          * is configured into the kernel. Since the regular hibernate
 815          * trigger path is via sysfs which takes a buffer mutex before
 816          * calling hibernate functions (which take system_transition_mutex)
 817          * this can cause lockdep to complain about a possible ABBA deadlock
 818          * which cannot happen since we're in the boot code here and
 819          * sysfs can't be invoked yet. Therefore, we use a subclass
 820          * here to avoid lockdep complaining.
 821          */
 822         mutex_lock_nested(&system_transition_mutex, SINGLE_DEPTH_NESTING);
 823
 824         if (swsusp_resume_device)
 825                 goto Check_image;
 826
 827         if (!strlen(resume_file)) {
 828                 error = -ENOENT;
 829                 goto Unlock;
 830         }
 831
 832         pm_pr_dbg("Checking hibernation image partition %s\n", resume_file);
 833
 834         if (resume_delay) {
 835                 pr_info("Waiting %dsec before reading resume device ...\n",
 836                         resume_delay);
 837                 ssleep(resume_delay);
 838         }
 839
 840         /* Check if the device is there */
 841         swsusp_resume_device = name_to_dev_t(resume_file);
 842
 843         /*
 844          * name_to_dev_t is ineffective to verify parition if resume_file is in
 845          * integer format. (e.g. major:minor)
 846          */
 847         if (isdigit(resume_file[0]) && resume_wait) {
 848                 int partno;
 849                 while (!get_gendisk(swsusp_resume_device, &partno))
 850                         msleep(10);
 851         }
 852
 853         if (!swsusp_resume_device) {
 854                 /*
 855                  * Some device discovery might still be in progress; we need
 856                  * to wait for this to finish.
 857                  */
 858                 wait_for_device_probe();
 859
 860                 if (resume_wait) {
 861                         while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
 862                                 msleep(10);
 863                         async_synchronize_full();
 864                 }
 865
 866                 swsusp_resume_device = name_to_dev_t(resume_file);
 867                 if (!swsusp_resume_device) {
 868                         error = -ENODEV;
 869                         goto Unlock;
 870                 }
 871         }
 872
 873  Check_image:
 874         pm_pr_dbg("Hibernation image partition %d:%d present\n",
 875                 MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 876
 877         pm_pr_dbg("Looking for hibernation image.\n");
 878         error = swsusp_check();
 879         if (error)
 880                 goto Unlock;
 881
 882         /* The snapshot device should not be opened while we're running */
 883         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 884                 error = -EBUSY;
 885                 swsusp_close(FMODE_READ);
 886                 goto Unlock;
 887         }
 888
 889         pr_info("resume from hibernation\n");
 890         pm_prepare_console();
 891         error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls);
 892         if (error) {
 893                 nr_calls--;
 894                 goto Close_Finish;
 895         }
 896
 897         pm_pr_dbg("Preparing processes for hibernation restore.\n");
 898         error = freeze_processes();
 899         if (error)
 900                 goto Close_Finish;
 901
 902         error = freeze_kernel_threads();
 903         if (error) {
 904                 thaw_processes();
 905                 goto Close_Finish;
 906         }
 907
 908         error = load_image_and_restore();
 909         thaw_processes();
 910  Finish:
 911         __pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);
 912         pm_restore_console();
 913         pr_info("resume failed (%d)\n", error);
 914         atomic_inc(&snapshot_device_available);
 915         /* For success case, the suspend path will release the lock */
 916  Unlock:
 917         mutex_unlock(&system_transition_mutex);
 918         pm_pr_dbg("Hibernation image not present or could not be loaded.\n");
 919         return error;
 920  Close_Finish:
 921         swsusp_close(FMODE_READ);
 922         goto Finish;
 923 }
 924
 925 late_initcall_sync(software_resume);
 926
 927
 928 static const char * const hibernation_modes[] = {
 929         [HIBERNATION_PLATFORM]  = "platform",
 930         [HIBERNATION_SHUTDOWN]  = "shutdown",
 931         [HIBERNATION_REBOOT]    = "reboot",
 932 #ifdef CONFIG_SUSPEND
 933         [HIBERNATION_SUSPEND]   = "suspend",
 934 #endif
 935         [HIBERNATION_TEST_RESUME]       = "test_resume",
 936 };
 937
 938 /*
 939  * /sys/power/disk - Control hibernation mode.
 940  *
 941  * Hibernation can be handled in several ways.  There are a few different ways
 942  * to put the system into the sleep state: using the platform driver (e.g. ACPI
 943  * or other hibernation_ops), powering it off or rebooting it (for testing
 944  * mostly).
 945  *
 946  * The sysfs file /sys/power/disk provides an interface for selecting the
 947  * hibernation mode to use.  Reading from this file causes the available modes
 948  * to be printed.  There are 3 modes that can be supported:
 949  *
 950  *      'platform'
 951  *      'shutdown'
 952  *      'reboot'
 953  *
 954  * If a platform hibernation driver is in use, 'platform' will be supported
 955  * and will be used by default.  Otherwise, 'shutdown' will be used by default.
 956  * The selected option (i.e. the one corresponding to the current value of
 957  * hibernation_mode) is enclosed by a square bracket.
 958  *
 959  * To select a given hibernation mode it is necessary to write the mode's
 960  * string representation (as returned by reading from /sys/power/disk) back
 961  * into /sys/power/disk.
 962  */
 963
 964 static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
 965                          char *buf)
 966 {
 967         int i;
 968         char *start = buf;
 969
 970         if (!hibernation_available())
 971                 return sprintf(buf, "[disabled]\n");
 972
 973         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 974                 if (!hibernation_modes[i])
 975                         continue;
 976                 switch (i) {
 977                 case HIBERNATION_SHUTDOWN:
 978                 case HIBERNATION_REBOOT:
 979 #ifdef CONFIG_SUSPEND
 980                 case HIBERNATION_SUSPEND:
 981 #endif
 982                 case HIBERNATION_TEST_RESUME:
 983                         break;
 984                 case HIBERNATION_PLATFORM:
 985                         if (hibernation_ops)
 986                                 break;
 987                         /* not a valid mode, continue with loop */
 988                         continue;
 989                 }
 990                 if (i == hibernation_mode)
 991                         buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
 992                 else
 993                         buf += sprintf(buf, "%s ", hibernation_modes[i]);
 994         }
 995         buf += sprintf(buf, "\n");
 996         return buf-start;
 997 }
 998
 999 static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
1000                           const char *buf, size_t n)
1001 {
1002         int error = 0;
1003         int i;
1004         int len;
1005         char *p;
1006         int mode = HIBERNATION_INVALID;
1007
1008         if (!hibernation_available())
1009                 return -EPERM;
1010
1011         p = memchr(buf, '\n', n);
1012         len = p ? p - buf : n;
1013
1014         lock_system_sleep();
1015         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
1016                 if (len == strlen(hibernation_modes[i])
1017                     && !strncmp(buf, hibernation_modes[i], len)) {
1018                         mode = i;
1019                         break;
1020                 }
1021         }
1022         if (mode != HIBERNATION_INVALID) {
1023                 switch (mode) {
1024                 case HIBERNATION_SHUTDOWN:
1025                 case HIBERNATION_REBOOT:
1026 #ifdef CONFIG_SUSPEND
1027                 case HIBERNATION_SUSPEND:
1028 #endif
1029                 case HIBERNATION_TEST_RESUME:
1030                         hibernation_mode = mode;
1031                         break;
1032                 case HIBERNATION_PLATFORM:
1033                         if (hibernation_ops)
1034                                 hibernation_mode = mode;
1035                         else
1036                                 error = -EINVAL;
1037                 }
1038         } else
1039                 error = -EINVAL;
1040
1041         if (!error)
1042                 pm_pr_dbg("Hibernation mode set to '%s'\n",
1043                                hibernation_modes[mode]);
1044         unlock_system_sleep();
1045         return error ? error : n;
1046 }
1047
1048 power_attr(disk);
1049
1050 static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
1051                            char *buf)
1052 {
1053         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
1054                        MINOR(swsusp_resume_device));
1055 }
1056
1057 static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
1058                             const char *buf, size_t n)
1059 {
1060         dev_t res;
1061         int len = n;
1062         char *name;
1063
1064         if (len && buf[len-1] == '\n')
1065                 len--;
1066         name = kstrndup(buf, len, GFP_KERNEL);
1067         if (!name)
1068                 return -ENOMEM;
1069
1070         res = name_to_dev_t(name);
1071         kfree(name);
1072         if (!res)
1073                 return -EINVAL;
1074
1075         lock_system_sleep();
1076         swsusp_resume_device = res;
1077         unlock_system_sleep();
1078         pm_pr_dbg("Configured hibernation resume from disk to %u\n",
1079                   swsusp_resume_device);
1080         noresume = 0;
1081         software_resume();
1082         return n;
1083 }
1084
1085 power_attr(resume);
1086
1087 static ssize_t resume_offset_show(struct kobject *kobj,
1088                                   struct kobj_attribute *attr, char *buf)
1089 {
1090         return sprintf(buf, "%llu\n", (unsigned long long)swsusp_resume_block);
1091 }
1092
1093 static ssize_t resume_offset_store(struct kobject *kobj,
1094                                    struct kobj_attribute *attr, const char *buf,
1095                                    size_t n)
1096 {
1097         unsigned long long offset;
1098         int rc;
1099
1100         rc = kstrtoull(buf, 0, &offset);
1101         if (rc)
1102                 return rc;
1103         swsusp_resume_block = offset;
1104
1105         return n;
1106 }
1107
1108 power_attr(resume_offset);
1109
1110 static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
1111                                char *buf)
1112 {
1113         return sprintf(buf, "%lu\n", image_size);
1114 }
1115
1116 static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
1117                                 const char *buf, size_t n)
1118 {
1119         unsigned long size;
1120
1121         if (sscanf(buf, "%lu", &size) == 1) {
1122                 image_size = size;
1123                 return n;
1124         }
1125
1126         return -EINVAL;
1127 }
1128
1129 power_attr(image_size);
1130
1131 static ssize_t reserved_size_show(struct kobject *kobj,
1132                                   struct kobj_attribute *attr, char *buf)
1133 {
1134         return sprintf(buf, "%lu\n", reserved_size);
1135 }
1136
1137 static ssize_t reserved_size_store(struct kobject *kobj,
1138                                    struct kobj_attribute *attr,
1139                                    const char *buf, size_t n)
1140 {
1141         unsigned long size;
1142
1143         if (sscanf(buf, "%lu", &size) == 1) {
1144                 reserved_size = size;
1145                 return n;
1146         }
1147
1148         return -EINVAL;
1149 }
1150
1151 power_attr(reserved_size);
1152
1153 static struct attribute * g[] = {
1154         &disk_attr.attr,
1155         &resume_offset_attr.attr,
1156         &resume_attr.attr,
1157         &image_size_attr.attr,
1158         &reserved_size_attr.attr,
1159         NULL,
1160 };
1161
1162
1163 static const struct attribute_group attr_group = {
1164         .attrs = g,
1165 };
1166
1167
1168 static int __init pm_disk_init(void)
1169 {
1170         return sysfs_create_group(power_kobj, &attr_group);
1171 }
1172
1173 core_initcall(pm_disk_init);
1174
1175
1176 static int __init resume_setup(char *str)
1177 {
1178         if (noresume)
1179                 return 1;
1180
1181         strncpy( resume_file, str, 255 );
1182         return 1;
1183 }
1184
1185 static int __init resume_offset_setup(char *str)
1186 {
1187         unsigned long long offset;
1188
1189         if (noresume)
1190                 return 1;
1191
1192         if (sscanf(str, "%llu", &offset) == 1)
1193                 swsusp_resume_block = offset;
1194
1195         return 1;
1196 }
1197
1198 static int __init hibernate_setup(char *str)
1199 {
1200         if (!strncmp(str, "noresume", 8)) {
1201                 noresume = 1;
1202         } else if (!strncmp(str, "nocompress", 10)) {
1203                 nocompress = 1;
1204         } else if (!strncmp(str, "no", 2)) {
1205                 noresume = 1;
1206                 nohibernate = 1;
1207         } else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)
1208                    && !strncmp(str, "protect_image", 13)) {
1209                 enable_restore_image_protection();
1210         }
1211         return 1;
1212 }
1213
1214 static int __init noresume_setup(char *str)
1215 {
1216         noresume = 1;
1217         return 1;
1218 }
1219
1220 static int __init resumewait_setup(char *str)
1221 {
1222         resume_wait = 1;
1223         return 1;
1224 }
1225
1226 static int __init resumedelay_setup(char *str)
1227 {
1228         int rc = kstrtouint(str, 0, &resume_delay);
1229
1230         if (rc)
1231                 return rc;
1232         return 1;
1233 }
1234
1235 static int __init nohibernate_setup(char *str)
1236 {
1237         noresume = 1;
1238         nohibernate = 1;
1239         return 1;
1240 }
1241
1242 __setup("noresume", noresume_setup);
1243 __setup("resume_offset=", resume_offset_setup);
1244 __setup("resume=", resume_setup);
1245 __setup("hibernate=", hibernate_setup);
1246 __setup("resumewait", resumewait_setup);
1247 __setup("resumedelay=", resumedelay_setup);
1248 __setup("nohibernate", nohibernate_setup);