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 static atomic_t hibernate_atomic = ATOMIC_INIT(1);
  71
  72 bool hibernate_acquire(void)
  73 {
  74         return atomic_add_unless(&hibernate_atomic, -1, 0);
  75 }
  76
  77 void hibernate_release(void)
  78 {
  79         atomic_inc(&hibernate_atomic);
  80 }
  81
  82 bool hibernation_available(void)
  83 {
  84         return nohibernate == 0 && !security_locked_down(LOCKDOWN_HIBERNATION);
  85 }
  86
  87 /**
  88  * hibernation_set_ops - Set the global hibernate operations.
  89  * @ops: Hibernation operations to use in subsequent hibernation transitions.
  90  */
  91 void hibernation_set_ops(const struct platform_hibernation_ops *ops)
  92 {
  93         if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
  94             && ops->prepare && ops->finish && ops->enter && ops->pre_restore
  95             && ops->restore_cleanup && ops->leave)) {
  96                 WARN_ON(1);
  97                 return;
  98         }
  99         lock_system_sleep();
 100         hibernation_ops = ops;
 101         if (ops)
 102                 hibernation_mode = HIBERNATION_PLATFORM;
 103         else if (hibernation_mode == HIBERNATION_PLATFORM)
 104                 hibernation_mode = HIBERNATION_SHUTDOWN;
 105
 106         unlock_system_sleep();
 107 }
 108 EXPORT_SYMBOL_GPL(hibernation_set_ops);
 109
 110 static bool entering_platform_hibernation;
 111
 112 bool system_entering_hibernation(void)
 113 {
 114         return entering_platform_hibernation;
 115 }
 116 EXPORT_SYMBOL(system_entering_hibernation);
 117
 118 #ifdef CONFIG_PM_DEBUG
 119 static void hibernation_debug_sleep(void)
 120 {
 121         pr_info("debug: Waiting for 5 seconds.\n");
 122         mdelay(5000);
 123 }
 124
 125 static int hibernation_test(int level)
 126 {
 127         if (pm_test_level == level) {
 128                 hibernation_debug_sleep();
 129                 return 1;
 130         }
 131         return 0;
 132 }
 133 #else /* !CONFIG_PM_DEBUG */
 134 static int hibernation_test(int level) { return 0; }
 135 #endif /* !CONFIG_PM_DEBUG */
 136
 137 /**
 138  * platform_begin - Call platform to start hibernation.
 139  * @platform_mode: Whether or not to use the platform driver.
 140  */
 141 static int platform_begin(int platform_mode)
 142 {
 143         return (platform_mode && hibernation_ops) ?
 144                 hibernation_ops->begin(PMSG_FREEZE) : 0;
 145 }
 146
 147 /**
 148  * platform_end - Call platform to finish transition to the working state.
 149  * @platform_mode: Whether or not to use the platform driver.
 150  */
 151 static void platform_end(int platform_mode)
 152 {
 153         if (platform_mode && hibernation_ops)
 154                 hibernation_ops->end();
 155 }
 156
 157 /**
 158  * platform_pre_snapshot - Call platform to prepare the machine for hibernation.
 159  * @platform_mode: Whether or not to use the platform driver.
 160  *
 161  * Use the platform driver to prepare the system for creating a hibernate image,
 162  * if so configured, and return an error code if that fails.
 163  */
 164
 165 static int platform_pre_snapshot(int platform_mode)
 166 {
 167         return (platform_mode && hibernation_ops) ?
 168                 hibernation_ops->pre_snapshot() : 0;
 169 }
 170
 171 /**
 172  * platform_leave - Call platform to prepare a transition to the working state.
 173  * @platform_mode: Whether or not to use the platform driver.
 174  *
 175  * Use the platform driver prepare to prepare the machine for switching to the
 176  * normal mode of operation.
 177  *
 178  * This routine is called on one CPU with interrupts disabled.
 179  */
 180 static void platform_leave(int platform_mode)
 181 {
 182         if (platform_mode && hibernation_ops)
 183                 hibernation_ops->leave();
 184 }
 185
 186 /**
 187  * platform_finish - Call platform to switch the system to the working state.
 188  * @platform_mode: Whether or not to use the platform driver.
 189  *
 190  * Use the platform driver to switch the machine to the normal mode of
 191  * operation.
 192  *
 193  * This routine must be called after platform_prepare().
 194  */
 195 static void platform_finish(int platform_mode)
 196 {
 197         if (platform_mode && hibernation_ops)
 198                 hibernation_ops->finish();
 199 }
 200
 201 /**
 202  * platform_pre_restore - Prepare for hibernate image restoration.
 203  * @platform_mode: Whether or not to use the platform driver.
 204  *
 205  * Use the platform driver to prepare the system for resume from a hibernation
 206  * image.
 207  *
 208  * If the restore fails after this function has been called,
 209  * platform_restore_cleanup() must be called.
 210  */
 211 static int platform_pre_restore(int platform_mode)
 212 {
 213         return (platform_mode && hibernation_ops) ?
 214                 hibernation_ops->pre_restore() : 0;
 215 }
 216
 217 /**
 218  * platform_restore_cleanup - Switch to the working state after failing restore.
 219  * @platform_mode: Whether or not to use the platform driver.
 220  *
 221  * Use the platform driver to switch the system to the normal mode of operation
 222  * after a failing restore.
 223  *
 224  * If platform_pre_restore() has been called before the failing restore, this
 225  * function must be called too, regardless of the result of
 226  * platform_pre_restore().
 227  */
 228 static void platform_restore_cleanup(int platform_mode)
 229 {
 230         if (platform_mode && hibernation_ops)
 231                 hibernation_ops->restore_cleanup();
 232 }
 233
 234 /**
 235  * platform_recover - Recover from a failure to suspend devices.
 236  * @platform_mode: Whether or not to use the platform driver.
 237  */
 238 static void platform_recover(int platform_mode)
 239 {
 240         if (platform_mode && hibernation_ops && hibernation_ops->recover)
 241                 hibernation_ops->recover();
 242 }
 243
 244 /**
 245  * swsusp_show_speed - Print time elapsed between two events during hibernation.
 246  * @start: Starting event.
 247  * @stop: Final event.
 248  * @nr_pages: Number of memory pages processed between @start and @stop.
 249  * @msg: Additional diagnostic message to print.
 250  */
 251 void swsusp_show_speed(ktime_t start, ktime_t stop,
 252                       unsigned nr_pages, char *msg)
 253 {
 254         ktime_t diff;
 255         u64 elapsed_centisecs64;
 256         unsigned int centisecs;
 257         unsigned int k;
 258         unsigned int kps;
 259
 260         diff = ktime_sub(stop, start);
 261         elapsed_centisecs64 = ktime_divns(diff, 10*NSEC_PER_MSEC);
 262         centisecs = elapsed_centisecs64;
 263         if (centisecs == 0)
 264                 centisecs = 1;  /* avoid div-by-zero */
 265         k = nr_pages * (PAGE_SIZE / 1024);
 266         kps = (k * 100) / centisecs;
 267         pr_info("%s %u kbytes in %u.%02u seconds (%u.%02u MB/s)\n",
 268                 msg, k, centisecs / 100, centisecs % 100, kps / 1000,
 269                 (kps % 1000) / 10);
 270 }
 271
 272 __weak int arch_resume_nosmt(void)
 273 {
 274         return 0;
 275 }
 276
 277 /**
 278  * create_image - Create a hibernation image.
 279  * @platform_mode: Whether or not to use the platform driver.
 280  *
 281  * Execute device drivers' "late" and "noirq" freeze callbacks, create a
 282  * hibernation image and run the drivers' "noirq" and "early" thaw callbacks.
 283  *
 284  * Control reappears in this routine after the subsequent restore.
 285  */
 286 static int create_image(int platform_mode)
 287 {
 288         int error;
 289
 290         error = dpm_suspend_end(PMSG_FREEZE);
 291         if (error) {
 292                 pr_err("Some devices failed to power down, aborting\n");
 293                 return error;
 294         }
 295
 296         error = platform_pre_snapshot(platform_mode);
 297         if (error || hibernation_test(TEST_PLATFORM))
 298                 goto Platform_finish;
 299
 300         error = suspend_disable_secondary_cpus();
 301         if (error || hibernation_test(TEST_CPUS))
 302                 goto Enable_cpus;
 303
 304         local_irq_disable();
 305
 306         system_state = SYSTEM_SUSPEND;
 307
 308         error = syscore_suspend();
 309         if (error) {
 310                 pr_err("Some system devices failed to power down, aborting\n");
 311                 goto Enable_irqs;
 312         }
 313
 314         if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
 315                 goto Power_up;
 316
 317         in_suspend = 1;
 318         save_processor_state();
 319         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);
 320         error = swsusp_arch_suspend();
 321         /* Restore control flow magically appears here */
 322         restore_processor_state();
 323         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
 324         if (error)
 325                 pr_err("Error %d creating image\n", error);
 326
 327         if (!in_suspend) {
 328                 events_check_enabled = false;
 329                 clear_free_pages();
 330         }
 331
 332         platform_leave(platform_mode);
 333
 334  Power_up:
 335         syscore_resume();
 336
 337  Enable_irqs:
 338         system_state = SYSTEM_RUNNING;
 339         local_irq_enable();
 340
 341  Enable_cpus:
 342         suspend_enable_secondary_cpus();
 343
 344         /* Allow architectures to do nosmt-specific post-resume dances */
 345         if (!in_suspend)
 346                 error = arch_resume_nosmt();
 347
 348  Platform_finish:
 349         platform_finish(platform_mode);
 350
 351         dpm_resume_start(in_suspend ?
 352                 (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
 353
 354         return error;
 355 }
 356
 357 /**
 358  * hibernation_snapshot - Quiesce devices and create a hibernation image.
 359  * @platform_mode: If set, use platform driver to prepare for the transition.
 360  *
 361  * This routine must be called with system_transition_mutex held.
 362  */
 363 int hibernation_snapshot(int platform_mode)
 364 {
 365         pm_message_t msg;
 366         int error;
 367
 368         pm_suspend_clear_flags();
 369         error = platform_begin(platform_mode);
 370         if (error)
 371                 goto Close;
 372
 373         /* Preallocate image memory before shutting down devices. */
 374         error = hibernate_preallocate_memory();
 375         if (error)
 376                 goto Close;
 377
 378         error = freeze_kernel_threads();
 379         if (error)
 380                 goto Cleanup;
 381
 382         if (hibernation_test(TEST_FREEZER)) {
 383
 384                 /*
 385                  * Indicate to the caller that we are returning due to a
 386                  * successful freezer test.
 387                  */
 388                 freezer_test_done = true;
 389                 goto Thaw;
 390         }
 391
 392         error = dpm_prepare(PMSG_FREEZE);
 393         if (error) {
 394                 dpm_complete(PMSG_RECOVER);
 395                 goto Thaw;
 396         }
 397
 398         suspend_console();
 399         pm_restrict_gfp_mask();
 400
 401         error = dpm_suspend(PMSG_FREEZE);
 402
 403         if (error || hibernation_test(TEST_DEVICES))
 404                 platform_recover(platform_mode);
 405         else
 406                 error = create_image(platform_mode);
 407
 408         /*
 409          * In the case that we call create_image() above, the control
 410          * returns here (1) after the image has been created or the
 411          * image creation has failed and (2) after a successful restore.
 412          */
 413
 414         /* We may need to release the preallocated image pages here. */
 415         if (error || !in_suspend)
 416                 swsusp_free();
 417
 418         msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
 419         dpm_resume(msg);
 420
 421         if (error || !in_suspend)
 422                 pm_restore_gfp_mask();
 423
 424         resume_console();
 425         dpm_complete(msg);
 426
 427  Close:
 428         platform_end(platform_mode);
 429         return error;
 430
 431  Thaw:
 432         thaw_kernel_threads();
 433  Cleanup:
 434         swsusp_free();
 435         goto Close;
 436 }
 437
 438 int __weak hibernate_resume_nonboot_cpu_disable(void)
 439 {
 440         return suspend_disable_secondary_cpus();
 441 }
 442
 443 /**
 444  * resume_target_kernel - Restore system state from a hibernation image.
 445  * @platform_mode: Whether or not to use the platform driver.
 446  *
 447  * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
 448  * contents of highmem that have not been restored yet from the image and run
 449  * the low-level code that will restore the remaining contents of memory and
 450  * switch to the just restored target kernel.
 451  */
 452 static int resume_target_kernel(bool platform_mode)
 453 {
 454         int error;
 455
 456         error = dpm_suspend_end(PMSG_QUIESCE);
 457         if (error) {
 458                 pr_err("Some devices failed to power down, aborting resume\n");
 459                 return error;
 460         }
 461
 462         error = platform_pre_restore(platform_mode);
 463         if (error)
 464                 goto Cleanup;
 465
 466         error = hibernate_resume_nonboot_cpu_disable();
 467         if (error)
 468                 goto Enable_cpus;
 469
 470         local_irq_disable();
 471         system_state = SYSTEM_SUSPEND;
 472
 473         error = syscore_suspend();
 474         if (error)
 475                 goto Enable_irqs;
 476
 477         save_processor_state();
 478         error = restore_highmem();
 479         if (!error) {
 480                 error = swsusp_arch_resume();
 481                 /*
 482                  * The code below is only ever reached in case of a failure.
 483                  * Otherwise, execution continues at the place where
 484                  * swsusp_arch_suspend() was called.
 485                  */
 486                 BUG_ON(!error);
 487                 /*
 488                  * This call to restore_highmem() reverts the changes made by
 489                  * the previous one.
 490                  */
 491                 restore_highmem();
 492         }
 493         /*
 494          * The only reason why swsusp_arch_resume() can fail is memory being
 495          * very tight, so we have to free it as soon as we can to avoid
 496          * subsequent failures.
 497          */
 498         swsusp_free();
 499         restore_processor_state();
 500         touch_softlockup_watchdog();
 501
 502         syscore_resume();
 503
 504  Enable_irqs:
 505         system_state = SYSTEM_RUNNING;
 506         local_irq_enable();
 507
 508  Enable_cpus:
 509         suspend_enable_secondary_cpus();
 510
 511  Cleanup:
 512         platform_restore_cleanup(platform_mode);
 513
 514         dpm_resume_start(PMSG_RECOVER);
 515
 516         return error;
 517 }
 518
 519 /**
 520  * hibernation_restore - Quiesce devices and restore from a hibernation image.
 521  * @platform_mode: If set, use platform driver to prepare for the transition.
 522  *
 523  * This routine must be called with system_transition_mutex held.  If it is
 524  * successful, control reappears in the restored target kernel in
 525  * hibernation_snapshot().
 526  */
 527 int hibernation_restore(int platform_mode)
 528 {
 529         int error;
 530
 531         pm_prepare_console();
 532         suspend_console();
 533         pm_restrict_gfp_mask();
 534         error = dpm_suspend_start(PMSG_QUIESCE);
 535         if (!error) {
 536                 error = resume_target_kernel(platform_mode);
 537                 /*
 538                  * The above should either succeed and jump to the new kernel,
 539                  * or return with an error. Otherwise things are just
 540                  * undefined, so let's be paranoid.
 541                  */
 542                 BUG_ON(!error);
 543         }
 544         dpm_resume_end(PMSG_RECOVER);
 545         pm_restore_gfp_mask();
 546         resume_console();
 547         pm_restore_console();
 548         return error;
 549 }
 550
 551 /**
 552  * hibernation_platform_enter - Power off the system using the platform driver.
 553  */
 554 int hibernation_platform_enter(void)
 555 {
 556         int error;
 557
 558         if (!hibernation_ops)
 559                 return -ENOSYS;
 560
 561         /*
 562          * We have cancelled the power transition by running
 563          * hibernation_ops->finish() before saving the image, so we should let
 564          * the firmware know that we're going to enter the sleep state after all
 565          */
 566         error = hibernation_ops->begin(PMSG_HIBERNATE);
 567         if (error)
 568                 goto Close;
 569
 570         entering_platform_hibernation = true;
 571         suspend_console();
 572         error = dpm_suspend_start(PMSG_HIBERNATE);
 573         if (error) {
 574                 if (hibernation_ops->recover)
 575                         hibernation_ops->recover();
 576                 goto Resume_devices;
 577         }
 578
 579         error = dpm_suspend_end(PMSG_HIBERNATE);
 580         if (error)
 581                 goto Resume_devices;
 582
 583         error = hibernation_ops->prepare();
 584         if (error)
 585                 goto Platform_finish;
 586
 587         error = suspend_disable_secondary_cpus();
 588         if (error)
 589                 goto Enable_cpus;
 590
 591         local_irq_disable();
 592         system_state = SYSTEM_SUSPEND;
 593         syscore_suspend();
 594         if (pm_wakeup_pending()) {
 595                 error = -EAGAIN;
 596                 goto Power_up;
 597         }
 598
 599         hibernation_ops->enter();
 600         /* We should never get here */
 601         while (1);
 602
 603  Power_up:
 604         syscore_resume();
 605         system_state = SYSTEM_RUNNING;
 606         local_irq_enable();
 607
 608  Enable_cpus:
 609         suspend_enable_secondary_cpus();
 610
 611  Platform_finish:
 612         hibernation_ops->finish();
 613
 614         dpm_resume_start(PMSG_RESTORE);
 615
 616  Resume_devices:
 617         entering_platform_hibernation = false;
 618         dpm_resume_end(PMSG_RESTORE);
 619         resume_console();
 620
 621  Close:
 622         hibernation_ops->end();
 623
 624         return error;
 625 }
 626
 627 /**
 628  * power_down - Shut the machine down for hibernation.
 629  *
 630  * Use the platform driver, if configured, to put the system into the sleep
 631  * state corresponding to hibernation, or try to power it off or reboot,
 632  * depending on the value of hibernation_mode.
 633  */
 634 static void power_down(void)
 635 {
 636 #ifdef CONFIG_SUSPEND
 637         int error;
 638
 639         if (hibernation_mode == HIBERNATION_SUSPEND) {
 640                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 641                 if (error) {
 642                         hibernation_mode = hibernation_ops ?
 643                                                 HIBERNATION_PLATFORM :
 644                                                 HIBERNATION_SHUTDOWN;
 645                 } else {
 646                         /* Restore swap signature. */
 647                         error = swsusp_unmark();
 648                         if (error)
 649                                 pr_err("Swap will be unusable! Try swapon -a.\n");
 650
 651                         return;
 652                 }
 653         }
 654 #endif
 655
 656         switch (hibernation_mode) {
 657         case HIBERNATION_REBOOT:
 658                 kernel_restart(NULL);
 659                 break;
 660         case HIBERNATION_PLATFORM:
 661                 hibernation_platform_enter();
 662                 /* Fall through */
 663         case HIBERNATION_SHUTDOWN:
 664                 if (pm_power_off)
 665                         kernel_power_off();
 666                 break;
 667         }
 668         kernel_halt();
 669         /*
 670          * Valid image is on the disk, if we continue we risk serious data
 671          * corruption after resume.
 672          */
 673         pr_crit("Power down manually\n");
 674         while (1)
 675                 cpu_relax();
 676 }
 677
 678 static int load_image_and_restore(void)
 679 {
 680         int error;
 681         unsigned int flags;
 682
 683         pm_pr_dbg("Loading hibernation image.\n");
 684
 685         lock_device_hotplug();
 686         error = create_basic_memory_bitmaps();
 687         if (error)
 688                 goto Unlock;
 689
 690         error = swsusp_read(&flags);
 691         swsusp_close(FMODE_READ);
 692         if (!error)
 693                 error = hibernation_restore(flags & SF_PLATFORM_MODE);
 694
 695         pr_err("Failed to load image, recovering.\n");
 696         swsusp_free();
 697         free_basic_memory_bitmaps();
 698  Unlock:
 699         unlock_device_hotplug();
 700
 701         return error;
 702 }
 703
 704 /**
 705  * hibernate - Carry out system hibernation, including saving the image.
 706  */
 707 int hibernate(void)
 708 {
 709         int error, nr_calls = 0;
 710         bool snapshot_test = false;
 711
 712         if (!hibernation_available()) {
 713                 pm_pr_dbg("Hibernation not available.\n");
 714                 return -EPERM;
 715         }
 716
 717         lock_system_sleep();
 718         /* The snapshot device should not be opened while we're running */
 719         if (!hibernate_acquire()) {
 720                 error = -EBUSY;
 721                 goto Unlock;
 722         }
 723
 724         pr_info("hibernation entry\n");
 725         pm_prepare_console();
 726         error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls);
 727         if (error) {
 728                 nr_calls--;
 729                 goto Exit;
 730         }
 731
 732         ksys_sync_helper();
 733
 734         error = freeze_processes();
 735         if (error)
 736                 goto Exit;
 737
 738         lock_device_hotplug();
 739         /* Allocate memory management structures */
 740         error = create_basic_memory_bitmaps();
 741         if (error)
 742                 goto Thaw;
 743
 744         error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
 745         if (error || freezer_test_done)
 746                 goto Free_bitmaps;
 747
 748         if (in_suspend) {
 749                 unsigned int flags = 0;
 750
 751                 if (hibernation_mode == HIBERNATION_PLATFORM)
 752                         flags |= SF_PLATFORM_MODE;
 753                 if (nocompress)
 754                         flags |= SF_NOCOMPRESS_MODE;
 755                 else
 756                         flags |= SF_CRC32_MODE;
 757
 758                 pm_pr_dbg("Writing hibernation image.\n");
 759                 error = swsusp_write(flags);
 760                 swsusp_free();
 761                 if (!error) {
 762                         if (hibernation_mode == HIBERNATION_TEST_RESUME)
 763                                 snapshot_test = true;
 764                         else
 765                                 power_down();
 766                 }
 767                 in_suspend = 0;
 768                 pm_restore_gfp_mask();
 769         } else {
 770                 pm_pr_dbg("Hibernation image restored successfully.\n");
 771         }
 772
 773  Free_bitmaps:
 774         free_basic_memory_bitmaps();
 775  Thaw:
 776         unlock_device_hotplug();
 777         if (snapshot_test) {
 778                 pm_pr_dbg("Checking hibernation image\n");
 779                 error = swsusp_check();
 780                 if (!error)
 781                         error = load_image_and_restore();
 782         }
 783         thaw_processes();
 784
 785         /* Don't bother checking whether freezer_test_done is true */
 786         freezer_test_done = false;
 787  Exit:
 788         __pm_notifier_call_chain(PM_POST_HIBERNATION, nr_calls, NULL);
 789         pm_restore_console();
 790         hibernate_release();
 791  Unlock:
 792         unlock_system_sleep();
 793         pr_info("hibernation exit\n");
 794
 795         return error;
 796 }
 797
 798
 799 /**
 800  * software_resume - Resume from a saved hibernation image.
 801  *
 802  * This routine is called as a late initcall, when all devices have been
 803  * discovered and initialized already.
 804  *
 805  * The image reading code is called to see if there is a hibernation image
 806  * available for reading.  If that is the case, devices are quiesced and the
 807  * contents of memory is restored from the saved image.
 808  *
 809  * If this is successful, control reappears in the restored target kernel in
 810  * hibernation_snapshot() which returns to hibernate().  Otherwise, the routine
 811  * attempts to recover gracefully and make the kernel return to the normal mode
 812  * of operation.
 813  */
 814 static int software_resume(void)
 815 {
 816         int error, nr_calls = 0;
 817
 818         /*
 819          * If the user said "noresume".. bail out early.
 820          */
 821         if (noresume || !hibernation_available())
 822                 return 0;
 823
 824         /*
 825          * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
 826          * is configured into the kernel. Since the regular hibernate
 827          * trigger path is via sysfs which takes a buffer mutex before
 828          * calling hibernate functions (which take system_transition_mutex)
 829          * this can cause lockdep to complain about a possible ABBA deadlock
 830          * which cannot happen since we're in the boot code here and
 831          * sysfs can't be invoked yet. Therefore, we use a subclass
 832          * here to avoid lockdep complaining.
 833          */
 834         mutex_lock_nested(&system_transition_mutex, SINGLE_DEPTH_NESTING);
 835
 836         if (swsusp_resume_device)
 837                 goto Check_image;
 838
 839         if (!strlen(resume_file)) {
 840                 error = -ENOENT;
 841                 goto Unlock;
 842         }
 843
 844         pm_pr_dbg("Checking hibernation image partition %s\n", resume_file);
 845
 846         if (resume_delay) {
 847                 pr_info("Waiting %dsec before reading resume device ...\n",
 848                         resume_delay);
 849                 ssleep(resume_delay);
 850         }
 851
 852         /* Check if the device is there */
 853         swsusp_resume_device = name_to_dev_t(resume_file);
 854
 855         /*
 856          * name_to_dev_t is ineffective to verify parition if resume_file is in
 857          * integer format. (e.g. major:minor)
 858          */
 859         if (isdigit(resume_file[0]) && resume_wait) {
 860                 int partno;
 861                 while (!get_gendisk(swsusp_resume_device, &partno))
 862                         msleep(10);
 863         }
 864
 865         if (!swsusp_resume_device) {
 866                 /*
 867                  * Some device discovery might still be in progress; we need
 868                  * to wait for this to finish.
 869                  */
 870                 wait_for_device_probe();
 871
 872                 if (resume_wait) {
 873                         while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
 874                                 msleep(10);
 875                         async_synchronize_full();
 876                 }
 877
 878                 swsusp_resume_device = name_to_dev_t(resume_file);
 879                 if (!swsusp_resume_device) {
 880                         error = -ENODEV;
 881                         goto Unlock;
 882                 }
 883         }
 884
 885  Check_image:
 886         pm_pr_dbg("Hibernation image partition %d:%d present\n",
 887                 MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 888
 889         pm_pr_dbg("Looking for hibernation image.\n");
 890         error = swsusp_check();
 891         if (error)
 892                 goto Unlock;
 893
 894         /* The snapshot device should not be opened while we're running */
 895         if (!hibernate_acquire()) {
 896                 error = -EBUSY;
 897                 swsusp_close(FMODE_READ);
 898                 goto Unlock;
 899         }
 900
 901         pr_info("resume from hibernation\n");
 902         pm_prepare_console();
 903         error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls);
 904         if (error) {
 905                 nr_calls--;
 906                 goto Close_Finish;
 907         }
 908
 909         pm_pr_dbg("Preparing processes for hibernation restore.\n");
 910         error = freeze_processes();
 911         if (error)
 912                 goto Close_Finish;
 913
 914         error = freeze_kernel_threads();
 915         if (error) {
 916                 thaw_processes();
 917                 goto Close_Finish;
 918         }
 919
 920         error = load_image_and_restore();
 921         thaw_processes();
 922  Finish:
 923         __pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);
 924         pm_restore_console();
 925         pr_info("resume failed (%d)\n", error);
 926         hibernate_release();
 927         /* For success case, the suspend path will release the lock */
 928  Unlock:
 929         mutex_unlock(&system_transition_mutex);
 930         pm_pr_dbg("Hibernation image not present or could not be loaded.\n");
 931         return error;
 932  Close_Finish:
 933         swsusp_close(FMODE_READ);
 934         goto Finish;
 935 }
 936
 937 late_initcall_sync(software_resume);
 938
 939
 940 static const char * const hibernation_modes[] = {
 941         [HIBERNATION_PLATFORM]  = "platform",
 942         [HIBERNATION_SHUTDOWN]  = "shutdown",
 943         [HIBERNATION_REBOOT]    = "reboot",
 944 #ifdef CONFIG_SUSPEND
 945         [HIBERNATION_SUSPEND]   = "suspend",
 946 #endif
 947         [HIBERNATION_TEST_RESUME]       = "test_resume",
 948 };
 949
 950 /*
 951  * /sys/power/disk - Control hibernation mode.
 952  *
 953  * Hibernation can be handled in several ways.  There are a few different ways
 954  * to put the system into the sleep state: using the platform driver (e.g. ACPI
 955  * or other hibernation_ops), powering it off or rebooting it (for testing
 956  * mostly).
 957  *
 958  * The sysfs file /sys/power/disk provides an interface for selecting the
 959  * hibernation mode to use.  Reading from this file causes the available modes
 960  * to be printed.  There are 3 modes that can be supported:
 961  *
 962  *      'platform'
 963  *      'shutdown'
 964  *      'reboot'
 965  *
 966  * If a platform hibernation driver is in use, 'platform' will be supported
 967  * and will be used by default.  Otherwise, 'shutdown' will be used by default.
 968  * The selected option (i.e. the one corresponding to the current value of
 969  * hibernation_mode) is enclosed by a square bracket.
 970  *
 971  * To select a given hibernation mode it is necessary to write the mode's
 972  * string representation (as returned by reading from /sys/power/disk) back
 973  * into /sys/power/disk.
 974  */
 975
 976 static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
 977                          char *buf)
 978 {
 979         int i;
 980         char *start = buf;
 981
 982         if (!hibernation_available())
 983                 return sprintf(buf, "[disabled]\n");
 984
 985         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 986                 if (!hibernation_modes[i])
 987                         continue;
 988                 switch (i) {
 989                 case HIBERNATION_SHUTDOWN:
 990                 case HIBERNATION_REBOOT:
 991 #ifdef CONFIG_SUSPEND
 992                 case HIBERNATION_SUSPEND:
 993 #endif
 994                 case HIBERNATION_TEST_RESUME:
 995                         break;
 996                 case HIBERNATION_PLATFORM:
 997                         if (hibernation_ops)
 998                                 break;
 999                         /* not a valid mode, continue with loop */
1000                         continue;
1001                 }
1002                 if (i == hibernation_mode)
1003                         buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
1004                 else
1005                         buf += sprintf(buf, "%s ", hibernation_modes[i]);
1006         }
1007         buf += sprintf(buf, "\n");
1008         return buf-start;
1009 }
1010
1011 static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
1012                           const char *buf, size_t n)
1013 {
1014         int error = 0;
1015         int i;
1016         int len;
1017         char *p;
1018         int mode = HIBERNATION_INVALID;
1019
1020         if (!hibernation_available())
1021                 return -EPERM;
1022
1023         p = memchr(buf, '\n', n);
1024         len = p ? p - buf : n;
1025
1026         lock_system_sleep();
1027         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
1028                 if (len == strlen(hibernation_modes[i])
1029                     && !strncmp(buf, hibernation_modes[i], len)) {
1030                         mode = i;
1031                         break;
1032                 }
1033         }
1034         if (mode != HIBERNATION_INVALID) {
1035                 switch (mode) {
1036                 case HIBERNATION_SHUTDOWN:
1037                 case HIBERNATION_REBOOT:
1038 #ifdef CONFIG_SUSPEND
1039                 case HIBERNATION_SUSPEND:
1040 #endif
1041                 case HIBERNATION_TEST_RESUME:
1042                         hibernation_mode = mode;
1043                         break;
1044                 case HIBERNATION_PLATFORM:
1045                         if (hibernation_ops)
1046                                 hibernation_mode = mode;
1047                         else
1048                                 error = -EINVAL;
1049                 }
1050         } else
1051                 error = -EINVAL;
1052
1053         if (!error)
1054                 pm_pr_dbg("Hibernation mode set to '%s'\n",
1055                                hibernation_modes[mode]);
1056         unlock_system_sleep();
1057         return error ? error : n;
1058 }
1059
1060 power_attr(disk);
1061
1062 static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
1063                            char *buf)
1064 {
1065         return sprintf(buf, "%d:%d\n", MAJOR(swsusp_resume_device),
1066                        MINOR(swsusp_resume_device));
1067 }
1068
1069 static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
1070                             const char *buf, size_t n)
1071 {
1072         dev_t res;
1073         int len = n;
1074         char *name;
1075
1076         if (len && buf[len-1] == '\n')
1077                 len--;
1078         name = kstrndup(buf, len, GFP_KERNEL);
1079         if (!name)
1080                 return -ENOMEM;
1081
1082         res = name_to_dev_t(name);
1083         kfree(name);
1084         if (!res)
1085                 return -EINVAL;
1086
1087         lock_system_sleep();
1088         swsusp_resume_device = res;
1089         unlock_system_sleep();
1090         pm_pr_dbg("Configured hibernation resume from disk to %u\n",
1091                   swsusp_resume_device);
1092         noresume = 0;
1093         software_resume();
1094         return n;
1095 }
1096
1097 power_attr(resume);
1098
1099 static ssize_t resume_offset_show(struct kobject *kobj,
1100                                   struct kobj_attribute *attr, char *buf)
1101 {
1102         return sprintf(buf, "%llu\n", (unsigned long long)swsusp_resume_block);
1103 }
1104
1105 static ssize_t resume_offset_store(struct kobject *kobj,
1106                                    struct kobj_attribute *attr, const char *buf,
1107                                    size_t n)
1108 {
1109         unsigned long long offset;
1110         int rc;
1111
1112         rc = kstrtoull(buf, 0, &offset);
1113         if (rc)
1114                 return rc;
1115         swsusp_resume_block = offset;
1116
1117         return n;
1118 }
1119
1120 power_attr(resume_offset);
1121
1122 static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
1123                                char *buf)
1124 {
1125         return sprintf(buf, "%lu\n", image_size);
1126 }
1127
1128 static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
1129                                 const char *buf, size_t n)
1130 {
1131         unsigned long size;
1132
1133         if (sscanf(buf, "%lu", &size) == 1) {
1134                 image_size = size;
1135                 return n;
1136         }
1137
1138         return -EINVAL;
1139 }
1140
1141 power_attr(image_size);
1142
1143 static ssize_t reserved_size_show(struct kobject *kobj,
1144                                   struct kobj_attribute *attr, char *buf)
1145 {
1146         return sprintf(buf, "%lu\n", reserved_size);
1147 }
1148
1149 static ssize_t reserved_size_store(struct kobject *kobj,
1150                                    struct kobj_attribute *attr,
1151                                    const char *buf, size_t n)
1152 {
1153         unsigned long size;
1154
1155         if (sscanf(buf, "%lu", &size) == 1) {
1156                 reserved_size = size;
1157                 return n;
1158         }
1159
1160         return -EINVAL;
1161 }
1162
1163 power_attr(reserved_size);
1164
1165 static struct attribute *g[] = {
1166         &disk_attr.attr,
1167         &resume_offset_attr.attr,
1168         &resume_attr.attr,
1169         &image_size_attr.attr,
1170         &reserved_size_attr.attr,
1171         NULL,
1172 };
1173
1174
1175 static const struct attribute_group attr_group = {
1176         .attrs = g,
1177 };
1178
1179
1180 static int __init pm_disk_init(void)
1181 {
1182         return sysfs_create_group(power_kobj, &attr_group);
1183 }
1184
1185 core_initcall(pm_disk_init);
1186
1187
1188 static int __init resume_setup(char *str)
1189 {
1190         if (noresume)
1191                 return 1;
1192
1193         strncpy(resume_file, str, 255);
1194         return 1;
1195 }
1196
1197 static int __init resume_offset_setup(char *str)
1198 {
1199         unsigned long long offset;
1200
1201         if (noresume)
1202                 return 1;
1203
1204         if (sscanf(str, "%llu", &offset) == 1)
1205                 swsusp_resume_block = offset;
1206
1207         return 1;
1208 }
1209
1210 static int __init hibernate_setup(char *str)
1211 {
1212         if (!strncmp(str, "noresume", 8)) {
1213                 noresume = 1;
1214         } else if (!strncmp(str, "nocompress", 10)) {
1215                 nocompress = 1;
1216         } else if (!strncmp(str, "no", 2)) {
1217                 noresume = 1;
1218                 nohibernate = 1;
1219         } else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)
1220                    && !strncmp(str, "protect_image", 13)) {
1221                 enable_restore_image_protection();
1222         }
1223         return 1;
1224 }
1225
1226 static int __init noresume_setup(char *str)
1227 {
1228         noresume = 1;
1229         return 1;
1230 }
1231
1232 static int __init resumewait_setup(char *str)
1233 {
1234         resume_wait = 1;
1235         return 1;
1236 }
1237
1238 static int __init resumedelay_setup(char *str)
1239 {
1240         int rc = kstrtouint(str, 0, &resume_delay);
1241
1242         if (rc)
1243                 return rc;
1244         return 1;
1245 }
1246
1247 static int __init nohibernate_setup(char *str)
1248 {
1249         noresume = 1;
1250         nohibernate = 1;
1251         return 1;
1252 }
1253
1254 __setup("noresume", noresume_setup);
1255 __setup("resume_offset=", resume_offset_setup);
1256 __setup("resume=", resume_setup);
1257 __setup("hibernate=", hibernate_setup);
1258 __setup("resumewait", resumewait_setup);
1259 __setup("resumedelay=", resumedelay_setup);
1260 __setup("nohibernate", nohibernate_setup);