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