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 <linux/secretmem.h>
  35 #include <trace/events/power.h>
  36
  37 #include "power.h"
  38
  39
  40 static int nocompress;
  41 static int noresume;
  42 static int nohibernate;
  43 static int resume_wait;
  44 static unsigned int resume_delay;
  45 static char resume_file[256] = CONFIG_PM_STD_PARTITION;
  46 dev_t swsusp_resume_device;
  47 sector_t swsusp_resume_block;
  48 __visible int in_suspend __nosavedata;
  49
  50 enum {
  51         HIBERNATION_INVALID,
  52         HIBERNATION_PLATFORM,
  53         HIBERNATION_SHUTDOWN,
  54         HIBERNATION_REBOOT,
  55 #ifdef CONFIG_SUSPEND
  56         HIBERNATION_SUSPEND,
  57 #endif
  58         HIBERNATION_TEST_RESUME,
  59         /* keep last */
  60         __HIBERNATION_AFTER_LAST
  61 };
  62 #define HIBERNATION_MAX (__HIBERNATION_AFTER_LAST-1)
  63 #define HIBERNATION_FIRST (HIBERNATION_INVALID + 1)
  64
  65 static int hibernation_mode = HIBERNATION_SHUTDOWN;
  66
  67 bool freezer_test_done;
  68
  69 static const struct platform_hibernation_ops *hibernation_ops;
  70
  71 static atomic_t hibernate_atomic = ATOMIC_INIT(1);
  72
  73 bool hibernate_acquire(void)
  74 {
  75         return atomic_add_unless(&hibernate_atomic, -1, 0);
  76 }
  77
  78 void hibernate_release(void)
  79 {
  80         atomic_inc(&hibernate_atomic);
  81 }
  82
  83 bool hibernation_available(void)
  84 {
  85         return nohibernate == 0 &&
  86                 !security_locked_down(LOCKDOWN_HIBERNATION) &&
  87                 !secretmem_active();
  88 }
  89
  90 /**
  91  * hibernation_set_ops - Set the global hibernate operations.
  92  * @ops: Hibernation operations to use in subsequent hibernation transitions.
  93  */
  94 void hibernation_set_ops(const struct platform_hibernation_ops *ops)
  95 {
  96         if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
  97             && ops->prepare && ops->finish && ops->enter && ops->pre_restore
  98             && ops->restore_cleanup && ops->leave)) {
  99                 WARN_ON(1);
 100                 return;
 101         }
 102         lock_system_sleep();
 103         hibernation_ops = ops;
 104         if (ops)
 105                 hibernation_mode = HIBERNATION_PLATFORM;
 106         else if (hibernation_mode == HIBERNATION_PLATFORM)
 107                 hibernation_mode = HIBERNATION_SHUTDOWN;
 108
 109         unlock_system_sleep();
 110 }
 111 EXPORT_SYMBOL_GPL(hibernation_set_ops);
 112
 113 static bool entering_platform_hibernation;
 114
 115 bool system_entering_hibernation(void)
 116 {
 117         return entering_platform_hibernation;
 118 }
 119 EXPORT_SYMBOL(system_entering_hibernation);
 120
 121 #ifdef CONFIG_PM_DEBUG
 122 static void hibernation_debug_sleep(void)
 123 {
 124         pr_info("debug: Waiting for 5 seconds.\n");
 125         mdelay(5000);
 126 }
 127
 128 static int hibernation_test(int level)
 129 {
 130         if (pm_test_level == level) {
 131                 hibernation_debug_sleep();
 132                 return 1;
 133         }
 134         return 0;
 135 }
 136 #else /* !CONFIG_PM_DEBUG */
 137 static int hibernation_test(int level) { return 0; }
 138 #endif /* !CONFIG_PM_DEBUG */
 139
 140 /**
 141  * platform_begin - Call platform to start hibernation.
 142  * @platform_mode: Whether or not to use the platform driver.
 143  */
 144 static int platform_begin(int platform_mode)
 145 {
 146         return (platform_mode && hibernation_ops) ?
 147                 hibernation_ops->begin(PMSG_FREEZE) : 0;
 148 }
 149
 150 /**
 151  * platform_end - Call platform to finish transition to the working state.
 152  * @platform_mode: Whether or not to use the platform driver.
 153  */
 154 static void platform_end(int platform_mode)
 155 {
 156         if (platform_mode && hibernation_ops)
 157                 hibernation_ops->end();
 158 }
 159
 160 /**
 161  * platform_pre_snapshot - Call platform to prepare the machine for hibernation.
 162  * @platform_mode: Whether or not to use the platform driver.
 163  *
 164  * Use the platform driver to prepare the system for creating a hibernate image,
 165  * if so configured, and return an error code if that fails.
 166  */
 167
 168 static int platform_pre_snapshot(int platform_mode)
 169 {
 170         return (platform_mode && hibernation_ops) ?
 171                 hibernation_ops->pre_snapshot() : 0;
 172 }
 173
 174 /**
 175  * platform_leave - Call platform to prepare a transition to the working state.
 176  * @platform_mode: Whether or not to use the platform driver.
 177  *
 178  * Use the platform driver prepare to prepare the machine for switching to the
 179  * normal mode of operation.
 180  *
 181  * This routine is called on one CPU with interrupts disabled.
 182  */
 183 static void platform_leave(int platform_mode)
 184 {
 185         if (platform_mode && hibernation_ops)
 186                 hibernation_ops->leave();
 187 }
 188
 189 /**
 190  * platform_finish - Call platform to switch the system to the working state.
 191  * @platform_mode: Whether or not to use the platform driver.
 192  *
 193  * Use the platform driver to switch the machine to the normal mode of
 194  * operation.
 195  *
 196  * This routine must be called after platform_prepare().
 197  */
 198 static void platform_finish(int platform_mode)
 199 {
 200         if (platform_mode && hibernation_ops)
 201                 hibernation_ops->finish();
 202 }
 203
 204 /**
 205  * platform_pre_restore - Prepare for hibernate image restoration.
 206  * @platform_mode: Whether or not to use the platform driver.
 207  *
 208  * Use the platform driver to prepare the system for resume from a hibernation
 209  * image.
 210  *
 211  * If the restore fails after this function has been called,
 212  * platform_restore_cleanup() must be called.
 213  */
 214 static int platform_pre_restore(int platform_mode)
 215 {
 216         return (platform_mode && hibernation_ops) ?
 217                 hibernation_ops->pre_restore() : 0;
 218 }
 219
 220 /**
 221  * platform_restore_cleanup - Switch to the working state after failing restore.
 222  * @platform_mode: Whether or not to use the platform driver.
 223  *
 224  * Use the platform driver to switch the system to the normal mode of operation
 225  * after a failing restore.
 226  *
 227  * If platform_pre_restore() has been called before the failing restore, this
 228  * function must be called too, regardless of the result of
 229  * platform_pre_restore().
 230  */
 231 static void platform_restore_cleanup(int platform_mode)
 232 {
 233         if (platform_mode && hibernation_ops)
 234                 hibernation_ops->restore_cleanup();
 235 }
 236
 237 /**
 238  * platform_recover - Recover from a failure to suspend devices.
 239  * @platform_mode: Whether or not to use the platform driver.
 240  */
 241 static void platform_recover(int platform_mode)
 242 {
 243         if (platform_mode && hibernation_ops && hibernation_ops->recover)
 244                 hibernation_ops->recover();
 245 }
 246
 247 /**
 248  * swsusp_show_speed - Print time elapsed between two events during hibernation.
 249  * @start: Starting event.
 250  * @stop: Final event.
 251  * @nr_pages: Number of memory pages processed between @start and @stop.
 252  * @msg: Additional diagnostic message to print.
 253  */
 254 void swsusp_show_speed(ktime_t start, ktime_t stop,
 255                       unsigned nr_pages, char *msg)
 256 {
 257         ktime_t diff;
 258         u64 elapsed_centisecs64;
 259         unsigned int centisecs;
 260         unsigned int k;
 261         unsigned int kps;
 262
 263         diff = ktime_sub(stop, start);
 264         elapsed_centisecs64 = ktime_divns(diff, 10*NSEC_PER_MSEC);
 265         centisecs = elapsed_centisecs64;
 266         if (centisecs == 0)
 267                 centisecs = 1;  /* avoid div-by-zero */
 268         k = nr_pages * (PAGE_SIZE / 1024);
 269         kps = (k * 100) / centisecs;
 270         pr_info("%s %u kbytes in %u.%02u seconds (%u.%02u MB/s)\n",
 271                 msg, k, centisecs / 100, centisecs % 100, kps / 1000,
 272                 (kps % 1000) / 10);
 273 }
 274
 275 __weak int arch_resume_nosmt(void)
 276 {
 277         return 0;
 278 }
 279
 280 /**
 281  * create_image - Create a hibernation image.
 282  * @platform_mode: Whether or not to use the platform driver.
 283  *
 284  * Execute device drivers' "late" and "noirq" freeze callbacks, create a
 285  * hibernation image and run the drivers' "noirq" and "early" thaw callbacks.
 286  *
 287  * Control reappears in this routine after the subsequent restore.
 288  */
 289 static int create_image(int platform_mode)
 290 {
 291         int error;
 292
 293         error = dpm_suspend_end(PMSG_FREEZE);
 294         if (error) {
 295                 pr_err("Some devices failed to power down, aborting\n");
 296                 return error;
 297         }
 298
 299         error = platform_pre_snapshot(platform_mode);
 300         if (error || hibernation_test(TEST_PLATFORM))
 301                 goto Platform_finish;
 302
 303         error = suspend_disable_secondary_cpus();
 304         if (error || hibernation_test(TEST_CPUS))
 305                 goto Enable_cpus;
 306
 307         local_irq_disable();
 308
 309         system_state = SYSTEM_SUSPEND;
 310
 311         error = syscore_suspend();
 312         if (error) {
 313                 pr_err("Some system devices failed to power down, aborting\n");
 314                 goto Enable_irqs;
 315         }
 316
 317         if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
 318                 goto Power_up;
 319
 320         in_suspend = 1;
 321         save_processor_state();
 322         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);
 323         error = swsusp_arch_suspend();
 324         /* Restore control flow magically appears here */
 325         restore_processor_state();
 326         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
 327         if (error)
 328                 pr_err("Error %d creating image\n", error);
 329
 330         if (!in_suspend) {
 331                 events_check_enabled = false;
 332                 clear_or_poison_free_pages();
 333         }
 334
 335         platform_leave(platform_mode);
 336
 337  Power_up:
 338         syscore_resume();
 339
 340  Enable_irqs:
 341         system_state = SYSTEM_RUNNING;
 342         local_irq_enable();
 343
 344  Enable_cpus:
 345         suspend_enable_secondary_cpus();
 346
 347         /* Allow architectures to do nosmt-specific post-resume dances */
 348         if (!in_suspend)
 349                 error = arch_resume_nosmt();
 350
 351  Platform_finish:
 352         platform_finish(platform_mode);
 353
 354         dpm_resume_start(in_suspend ?
 355                 (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
 356
 357         return error;
 358 }
 359
 360 /**
 361  * hibernation_snapshot - Quiesce devices and create a hibernation image.
 362  * @platform_mode: If set, use platform driver to prepare for the transition.
 363  *
 364  * This routine must be called with system_transition_mutex held.
 365  */
 366 int hibernation_snapshot(int platform_mode)
 367 {
 368         pm_message_t msg;
 369         int error;
 370
 371         pm_suspend_clear_flags();
 372         error = platform_begin(platform_mode);
 373         if (error)
 374                 goto Close;
 375
 376         /* Preallocate image memory before shutting down devices. */
 377         error = hibernate_preallocate_memory();
 378         if (error)
 379                 goto Close;
 380
 381         error = freeze_kernel_threads();
 382         if (error)
 383                 goto Cleanup;
 384
 385         if (hibernation_test(TEST_FREEZER)) {
 386
 387                 /*
 388                  * Indicate to the caller that we are returning due to a
 389                  * successful freezer test.
 390                  */
 391                 freezer_test_done = true;
 392                 goto Thaw;
 393         }
 394
 395         error = dpm_prepare(PMSG_FREEZE);
 396         if (error) {
 397                 dpm_complete(PMSG_RECOVER);
 398                 goto Thaw;
 399         }
 400
 401         suspend_console();
 402         pm_restrict_gfp_mask();
 403
 404         error = dpm_suspend(PMSG_FREEZE);
 405
 406         if (error || hibernation_test(TEST_DEVICES))
 407                 platform_recover(platform_mode);
 408         else
 409                 error = create_image(platform_mode);
 410
 411         /*
 412          * In the case that we call create_image() above, the control
 413          * returns here (1) after the image has been created or the
 414          * image creation has failed and (2) after a successful restore.
 415          */
 416
 417         /* We may need to release the preallocated image pages here. */
 418         if (error || !in_suspend)
 419                 swsusp_free();
 420
 421         msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
 422         dpm_resume(msg);
 423
 424         if (error || !in_suspend)
 425                 pm_restore_gfp_mask();
 426
 427         resume_console();
 428         dpm_complete(msg);
 429
 430  Close:
 431         platform_end(platform_mode);
 432         return error;
 433
 434  Thaw:
 435         thaw_kernel_threads();
 436  Cleanup:
 437         swsusp_free();
 438         goto Close;
 439 }
 440
 441 int __weak hibernate_resume_nonboot_cpu_disable(void)
 442 {
 443         return suspend_disable_secondary_cpus();
 444 }
 445
 446 /**
 447  * resume_target_kernel - Restore system state from a hibernation image.
 448  * @platform_mode: Whether or not to use the platform driver.
 449  *
 450  * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
 451  * contents of highmem that have not been restored yet from the image and run
 452  * the low-level code that will restore the remaining contents of memory and
 453  * switch to the just restored target kernel.
 454  */
 455 static int resume_target_kernel(bool platform_mode)
 456 {
 457         int error;
 458
 459         error = dpm_suspend_end(PMSG_QUIESCE);
 460         if (error) {
 461                 pr_err("Some devices failed to power down, aborting resume\n");
 462                 return error;
 463         }
 464
 465         error = platform_pre_restore(platform_mode);
 466         if (error)
 467                 goto Cleanup;
 468
 469         error = hibernate_resume_nonboot_cpu_disable();
 470         if (error)
 471                 goto Enable_cpus;
 472
 473         local_irq_disable();
 474         system_state = SYSTEM_SUSPEND;
 475
 476         error = syscore_suspend();
 477         if (error)
 478                 goto Enable_irqs;
 479
 480         save_processor_state();
 481         error = restore_highmem();
 482         if (!error) {
 483                 error = swsusp_arch_resume();
 484                 /*
 485                  * The code below is only ever reached in case of a failure.
 486                  * Otherwise, execution continues at the place where
 487                  * swsusp_arch_suspend() was called.
 488                  */
 489                 BUG_ON(!error);
 490                 /*
 491                  * This call to restore_highmem() reverts the changes made by
 492                  * the previous one.
 493                  */
 494                 restore_highmem();
 495         }
 496         /*
 497          * The only reason why swsusp_arch_resume() can fail is memory being
 498          * very tight, so we have to free it as soon as we can to avoid
 499          * subsequent failures.
 500          */
 501         swsusp_free();
 502         restore_processor_state();
 503         touch_softlockup_watchdog();
 504
 505         syscore_resume();
 506
 507  Enable_irqs:
 508         system_state = SYSTEM_RUNNING;
 509         local_irq_enable();
 510
 511  Enable_cpus:
 512         suspend_enable_secondary_cpus();
 513
 514  Cleanup:
 515         platform_restore_cleanup(platform_mode);
 516
 517         dpm_resume_start(PMSG_RECOVER);
 518
 519         return error;
 520 }
 521
 522 /**
 523  * hibernation_restore - Quiesce devices and restore from a hibernation image.
 524  * @platform_mode: If set, use platform driver to prepare for the transition.
 525  *
 526  * This routine must be called with system_transition_mutex held.  If it is
 527  * successful, control reappears in the restored target kernel in
 528  * hibernation_snapshot().
 529  */
 530 int hibernation_restore(int platform_mode)
 531 {
 532         int error;
 533
 534         pm_prepare_console();
 535         suspend_console();
 536         pm_restrict_gfp_mask();
 537         error = dpm_suspend_start(PMSG_QUIESCE);
 538         if (!error) {
 539                 error = resume_target_kernel(platform_mode);
 540                 /*
 541                  * The above should either succeed and jump to the new kernel,
 542                  * or return with an error. Otherwise things are just
 543                  * undefined, so let's be paranoid.
 544                  */
 545                 BUG_ON(!error);
 546         }
 547         dpm_resume_end(PMSG_RECOVER);
 548         pm_restore_gfp_mask();
 549         resume_console();
 550         pm_restore_console();
 551         return error;
 552 }
 553
 554 /**
 555  * hibernation_platform_enter - Power off the system using the platform driver.
 556  */
 557 int hibernation_platform_enter(void)
 558 {
 559         int error;
 560
 561         if (!hibernation_ops)
 562                 return -ENOSYS;
 563
 564         /*
 565          * We have cancelled the power transition by running
 566          * hibernation_ops->finish() before saving the image, so we should let
 567          * the firmware know that we're going to enter the sleep state after all
 568          */
 569         error = hibernation_ops->begin(PMSG_HIBERNATE);
 570         if (error)
 571                 goto Close;
 572
 573         entering_platform_hibernation = true;
 574         suspend_console();
 575         error = dpm_suspend_start(PMSG_HIBERNATE);
 576         if (error) {
 577                 if (hibernation_ops->recover)
 578                         hibernation_ops->recover();
 579                 goto Resume_devices;
 580         }
 581
 582         error = dpm_suspend_end(PMSG_HIBERNATE);
 583         if (error)
 584                 goto Resume_devices;
 585
 586         error = hibernation_ops->prepare();
 587         if (error)
 588                 goto Platform_finish;
 589
 590         error = suspend_disable_secondary_cpus();
 591         if (error)
 592                 goto Enable_cpus;
 593
 594         local_irq_disable();
 595         system_state = SYSTEM_SUSPEND;
 596         syscore_suspend();
 597         if (pm_wakeup_pending()) {
 598                 error = -EAGAIN;
 599                 goto Power_up;
 600         }
 601
 602         hibernation_ops->enter();
 603         /* We should never get here */
 604         while (1);
 605
 606  Power_up:
 607         syscore_resume();
 608         system_state = SYSTEM_RUNNING;
 609         local_irq_enable();
 610
 611  Enable_cpus:
 612         suspend_enable_secondary_cpus();
 613
 614  Platform_finish:
 615         hibernation_ops->finish();
 616
 617         dpm_resume_start(PMSG_RESTORE);
 618
 619  Resume_devices:
 620         entering_platform_hibernation = false;
 621         dpm_resume_end(PMSG_RESTORE);
 622         resume_console();
 623
 624  Close:
 625         hibernation_ops->end();
 626
 627         return error;
 628 }
 629
 630 /**
 631  * power_down - Shut the machine down for hibernation.
 632  *
 633  * Use the platform driver, if configured, to put the system into the sleep
 634  * state corresponding to hibernation, or try to power it off or reboot,
 635  * depending on the value of hibernation_mode.
 636  */
 637 static void power_down(void)
 638 {
 639 #ifdef CONFIG_SUSPEND
 640         int error;
 641
 642         if (hibernation_mode == HIBERNATION_SUSPEND) {
 643                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 644                 if (error) {
 645                         hibernation_mode = hibernation_ops ?
 646                                                 HIBERNATION_PLATFORM :
 647                                                 HIBERNATION_SHUTDOWN;
 648                 } else {
 649                         /* Restore swap signature. */
 650                         error = swsusp_unmark();
 651                         if (error)
 652                                 pr_err("Swap will be unusable! Try swapon -a.\n");
 653
 654                         return;
 655                 }
 656         }
 657 #endif
 658
 659         switch (hibernation_mode) {
 660         case HIBERNATION_REBOOT:
 661                 kernel_restart(NULL);
 662                 break;
 663         case HIBERNATION_PLATFORM:
 664                 hibernation_platform_enter();
 665                 fallthrough;
 666         case HIBERNATION_SHUTDOWN:
 667                 if (pm_power_off)
 668                         kernel_power_off();
 669                 break;
 670         }
 671         kernel_halt();
 672         /*
 673          * Valid image is on the disk, if we continue we risk serious data
 674          * corruption after resume.
 675          */
 676         pr_crit("Power down manually\n");
 677         while (1)
 678                 cpu_relax();
 679 }
 680
 681 static int load_image_and_restore(void)
 682 {
 683         int error;
 684         unsigned int flags;
 685
 686         pm_pr_dbg("Loading hibernation image.\n");
 687
 688         lock_device_hotplug();
 689         error = create_basic_memory_bitmaps();
 690         if (error)
 691                 goto Unlock;
 692
 693         error = swsusp_read(&flags);
 694         swsusp_close(FMODE_READ);
 695         if (!error)
 696                 error = hibernation_restore(flags & SF_PLATFORM_MODE);
 697
 698         pr_err("Failed to load image, recovering.\n");
 699         swsusp_free();
 700         free_basic_memory_bitmaps();
 701  Unlock:
 702         unlock_device_hotplug();
 703
 704         return error;
 705 }
 706
 707 /**
 708  * hibernate - Carry out system hibernation, including saving the image.
 709  */
 710 int hibernate(void)
 711 {
 712         bool snapshot_test = false;
 713         int error;
 714
 715         if (!hibernation_available()) {
 716                 pm_pr_dbg("Hibernation not available.\n");
 717                 return -EPERM;
 718         }
 719
 720         lock_system_sleep();
 721         /* The snapshot device should not be opened while we're running */
 722         if (!hibernate_acquire()) {
 723                 error = -EBUSY;
 724                 goto Unlock;
 725         }
 726
 727         pr_info("hibernation entry\n");
 728         pm_prepare_console();
 729         error = pm_notifier_call_chain_robust(PM_HIBERNATION_PREPARE, PM_POST_HIBERNATION);
 730         if (error)
 731                 goto Restore;
 732
 733         ksys_sync_helper();
 734
 735         error = freeze_processes();
 736         if (error)
 737                 goto Exit;
 738
 739         lock_device_hotplug();
 740         /* Allocate memory management structures */
 741         error = create_basic_memory_bitmaps();
 742         if (error)
 743                 goto Thaw;
 744
 745         error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
 746         if (error || freezer_test_done)
 747                 goto Free_bitmaps;
 748
 749         if (in_suspend) {
 750                 unsigned int flags = 0;
 751
 752                 if (hibernation_mode == HIBERNATION_PLATFORM)
 753                         flags |= SF_PLATFORM_MODE;
 754                 if (nocompress)
 755                         flags |= SF_NOCOMPRESS_MODE;
 756                 else
 757                         flags |= SF_CRC32_MODE;
 758
 759                 pm_pr_dbg("Writing hibernation image.\n");
 760                 error = swsusp_write(flags);
 761                 swsusp_free();
 762                 if (!error) {
 763                         if (hibernation_mode == HIBERNATION_TEST_RESUME)
 764                                 snapshot_test = true;
 765                         else
 766                                 power_down();
 767                 }
 768                 in_suspend = 0;
 769                 pm_restore_gfp_mask();
 770         } else {
 771                 pm_pr_dbg("Hibernation image restored successfully.\n");
 772         }
 773
 774  Free_bitmaps:
 775         free_basic_memory_bitmaps();
 776  Thaw:
 777         unlock_device_hotplug();
 778         if (snapshot_test) {
 779                 pm_pr_dbg("Checking hibernation image\n");
 780                 error = swsusp_check();
 781                 if (!error)
 782                         error = load_image_and_restore();
 783         }
 784         thaw_processes();
 785
 786         /* Don't bother checking whether freezer_test_done is true */
 787         freezer_test_done = false;
 788  Exit:
 789         pm_notifier_call_chain(PM_POST_HIBERNATION);
 790  Restore:
 791         pm_restore_console();
 792         hibernate_release();
 793  Unlock:
 794         unlock_system_sleep();
 795         pr_info("hibernation exit\n");
 796
 797         return error;
 798 }
 799
 800 /**
 801  * hibernate_quiet_exec - Execute a function with all devices frozen.
 802  * @func: Function to execute.
 803  * @data: Data pointer to pass to @func.
 804  *
 805  * Return the @func return value or an error code if it cannot be executed.
 806  */
 807 int hibernate_quiet_exec(int (*func)(void *data), void *data)
 808 {
 809         int error;
 810
 811         lock_system_sleep();
 812
 813         if (!hibernate_acquire()) {
 814                 error = -EBUSY;
 815                 goto unlock;
 816         }
 817
 818         pm_prepare_console();
 819
 820         error = pm_notifier_call_chain_robust(PM_HIBERNATION_PREPARE, PM_POST_HIBERNATION);
 821         if (error)
 822                 goto restore;
 823
 824         error = freeze_processes();
 825         if (error)
 826                 goto exit;
 827
 828         lock_device_hotplug();
 829
 830         pm_suspend_clear_flags();
 831
 832         error = platform_begin(true);
 833         if (error)
 834                 goto thaw;
 835
 836         error = freeze_kernel_threads();
 837         if (error)
 838                 goto thaw;
 839
 840         error = dpm_prepare(PMSG_FREEZE);
 841         if (error)
 842                 goto dpm_complete;
 843
 844         suspend_console();
 845
 846         error = dpm_suspend(PMSG_FREEZE);
 847         if (error)
 848                 goto dpm_resume;
 849
 850         error = dpm_suspend_end(PMSG_FREEZE);
 851         if (error)
 852                 goto dpm_resume;
 853
 854         error = platform_pre_snapshot(true);
 855         if (error)
 856                 goto skip;
 857
 858         error = func(data);
 859
 860 skip:
 861         platform_finish(true);
 862
 863         dpm_resume_start(PMSG_THAW);
 864
 865 dpm_resume:
 866         dpm_resume(PMSG_THAW);
 867
 868         resume_console();
 869
 870 dpm_complete:
 871         dpm_complete(PMSG_THAW);
 872
 873         thaw_kernel_threads();
 874
 875 thaw:
 876         platform_end(true);
 877
 878         unlock_device_hotplug();
 879
 880         thaw_processes();
 881
 882 exit:
 883         pm_notifier_call_chain(PM_POST_HIBERNATION);
 884
 885 restore:
 886         pm_restore_console();
 887
 888         hibernate_release();
 889
 890 unlock:
 891         unlock_system_sleep();
 892
 893         return error;
 894 }
 895 EXPORT_SYMBOL_GPL(hibernate_quiet_exec);
 896
 897 /**
 898  * software_resume - Resume from a saved hibernation image.
 899  *
 900  * This routine is called as a late initcall, when all devices have been
 901  * discovered and initialized already.
 902  *
 903  * The image reading code is called to see if there is a hibernation image
 904  * available for reading.  If that is the case, devices are quiesced and the
 905  * contents of memory is restored from the saved image.
 906  *
 907  * If this is successful, control reappears in the restored target kernel in
 908  * hibernation_snapshot() which returns to hibernate().  Otherwise, the routine
 909  * attempts to recover gracefully and make the kernel return to the normal mode
 910  * of operation.
 911  */
 912 static int software_resume(void)
 913 {
 914         int error;
 915
 916         /*
 917          * If the user said "noresume".. bail out early.
 918          */
 919         if (noresume || !hibernation_available())
 920                 return 0;
 921
 922         /*
 923          * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
 924          * is configured into the kernel. Since the regular hibernate
 925          * trigger path is via sysfs which takes a buffer mutex before
 926          * calling hibernate functions (which take system_transition_mutex)
 927          * this can cause lockdep to complain about a possible ABBA deadlock
 928          * which cannot happen since we're in the boot code here and
 929          * sysfs can't be invoked yet. Therefore, we use a subclass
 930          * here to avoid lockdep complaining.
 931          */
 932         mutex_lock_nested(&system_transition_mutex, SINGLE_DEPTH_NESTING);
 933
 934         if (swsusp_resume_device)
 935                 goto Check_image;
 936
 937         if (!strlen(resume_file)) {
 938                 error = -ENOENT;
 939                 goto Unlock;
 940         }
 941
 942         pm_pr_dbg("Checking hibernation image partition %s\n", resume_file);
 943
 944         if (resume_delay) {
 945                 pr_info("Waiting %dsec before reading resume device ...\n",
 946                         resume_delay);
 947                 ssleep(resume_delay);
 948         }
 949
 950         /* Check if the device is there */
 951         swsusp_resume_device = name_to_dev_t(resume_file);
 952         if (!swsusp_resume_device) {
 953                 /*
 954                  * Some device discovery might still be in progress; we need
 955                  * to wait for this to finish.
 956                  */
 957                 wait_for_device_probe();
 958
 959                 if (resume_wait) {
 960                         while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
 961                                 msleep(10);
 962                         async_synchronize_full();
 963                 }
 964
 965                 swsusp_resume_device = name_to_dev_t(resume_file);
 966                 if (!swsusp_resume_device) {
 967                         error = -ENODEV;
 968                         goto Unlock;
 969                 }
 970         }
 971
 972  Check_image:
 973         pm_pr_dbg("Hibernation image partition %d:%d present\n",
 974                 MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 975
 976         pm_pr_dbg("Looking for hibernation image.\n");
 977         error = swsusp_check();
 978         if (error)
 979                 goto Unlock;
 980
 981         /* The snapshot device should not be opened while we're running */
 982         if (!hibernate_acquire()) {
 983                 error = -EBUSY;
 984                 swsusp_close(FMODE_READ);
 985                 goto Unlock;
 986         }
 987
 988         pr_info("resume from hibernation\n");
 989         pm_prepare_console();
 990         error = pm_notifier_call_chain_robust(PM_RESTORE_PREPARE, PM_POST_RESTORE);
 991         if (error)
 992                 goto Restore;
 993
 994         pm_pr_dbg("Preparing processes for hibernation restore.\n");
 995         error = freeze_processes();
 996         if (error)
 997                 goto Close_Finish;
 998
 999         error = freeze_kernel_threads();
1000         if (error) {
1001                 thaw_processes();
1002                 goto Close_Finish;
1003         }
1004
1005         error = load_image_and_restore();
1006         thaw_processes();
1007  Finish:
1008         pm_notifier_call_chain(PM_POST_RESTORE);
1009  Restore:
1010         pm_restore_console();
1011         pr_info("resume failed (%d)\n", error);
1012         hibernate_release();
1013         /* For success case, the suspend path will release the lock */
1014  Unlock:
1015         mutex_unlock(&system_transition_mutex);
1016         pm_pr_dbg("Hibernation image not present or could not be loaded.\n");
1017         return error;
1018  Close_Finish:
1019         swsusp_close(FMODE_READ);
1020         goto Finish;
1021 }
1022
1023 late_initcall_sync(software_resume);
1024
1025
1026 static const char * const hibernation_modes[] = {
1027         [HIBERNATION_PLATFORM]  = "platform",
1028         [HIBERNATION_SHUTDOWN]  = "shutdown",
1029         [HIBERNATION_REBOOT]    = "reboot",
1030 #ifdef CONFIG_SUSPEND
1031         [HIBERNATION_SUSPEND]   = "suspend",
1032 #endif
1033         [HIBERNATION_TEST_RESUME]       = "test_resume",
1034 };
1035
1036 /*
1037  * /sys/power/disk - Control hibernation mode.
1038  *
1039  * Hibernation can be handled in several ways.  There are a few different ways
1040  * to put the system into the sleep state: using the platform driver (e.g. ACPI
1041  * or other hibernation_ops), powering it off or rebooting it (for testing
1042  * mostly).
1043  *
1044  * The sysfs file /sys/power/disk provides an interface for selecting the
1045  * hibernation mode to use.  Reading from this file causes the available modes
1046  * to be printed.  There are 3 modes that can be supported:
1047  *
1048  *      'platform'
1049  *      'shutdown'
1050  *      'reboot'
1051  *
1052  * If a platform hibernation driver is in use, 'platform' will be supported
1053  * and will be used by default.  Otherwise, 'shutdown' will be used by default.
1054  * The selected option (i.e. the one corresponding to the current value of
1055  * hibernation_mode) is enclosed by a square bracket.
1056  *
1057  * To select a given hibernation mode it is necessary to write the mode's
1058  * string representation (as returned by reading from /sys/power/disk) back
1059  * into /sys/power/disk.
1060  */
1061
1062 static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
1063                          char *buf)
1064 {
1065         int i;
1066         char *start = buf;
1067
1068         if (!hibernation_available())
1069                 return sprintf(buf, "[disabled]\n");
1070
1071         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
1072                 if (!hibernation_modes[i])
1073                         continue;
1074                 switch (i) {
1075                 case HIBERNATION_SHUTDOWN:
1076                 case HIBERNATION_REBOOT:
1077 #ifdef CONFIG_SUSPEND
1078                 case HIBERNATION_SUSPEND:
1079 #endif
1080                 case HIBERNATION_TEST_RESUME:
1081                         break;
1082                 case HIBERNATION_PLATFORM:
1083                         if (hibernation_ops)
1084                                 break;
1085                         /* not a valid mode, continue with loop */
1086                         continue;
1087                 }
1088                 if (i == hibernation_mode)
1089                         buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
1090                 else
1091                         buf += sprintf(buf, "%s ", hibernation_modes[i]);
1092         }
1093         buf += sprintf(buf, "\n");
1094         return buf-start;
1095 }
1096
1097 static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
1098                           const char *buf, size_t n)
1099 {
1100         int error = 0;
1101         int i;
1102         int len;
1103         char *p;
1104         int mode = HIBERNATION_INVALID;
1105
1106         if (!hibernation_available())
1107                 return -EPERM;
1108
1109         p = memchr(buf, '\n', n);
1110         len = p ? p - buf : n;
1111
1112         lock_system_sleep();
1113         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
1114                 if (len == strlen(hibernation_modes[i])
1115                     && !strncmp(buf, hibernation_modes[i], len)) {
1116                         mode = i;
1117                         break;
1118                 }
1119         }
1120         if (mode != HIBERNATION_INVALID) {
1121                 switch (mode) {
1122                 case HIBERNATION_SHUTDOWN:
1123                 case HIBERNATION_REBOOT:
1124 #ifdef CONFIG_SUSPEND
1125                 case HIBERNATION_SUSPEND:
1126 #endif
1127                 case HIBERNATION_TEST_RESUME:
1128                         hibernation_mode = mode;
1129                         break;
1130                 case HIBERNATION_PLATFORM:
1131                         if (hibernation_ops)
1132                                 hibernation_mode = mode;
1133                         else
1134                                 error = -EINVAL;
1135                 }
1136         } else
1137                 error = -EINVAL;
1138
1139         if (!error)
1140                 pm_pr_dbg("Hibernation mode set to '%s'\n",
1141                                hibernation_modes[mode]);
1142         unlock_system_sleep();
1143         return error ? error : n;
1144 }
1145
1146 power_attr(disk);
1147
1148 static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
1149                            char *buf)
1150 {
1151         return sprintf(buf, "%d:%d\n", MAJOR(swsusp_resume_device),
1152                        MINOR(swsusp_resume_device));
1153 }
1154
1155 static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
1156                             const char *buf, size_t n)
1157 {
1158         dev_t res;
1159         int len = n;
1160         char *name;
1161
1162         if (len && buf[len-1] == '\n')
1163                 len--;
1164         name = kstrndup(buf, len, GFP_KERNEL);
1165         if (!name)
1166                 return -ENOMEM;
1167
1168         res = name_to_dev_t(name);
1169         kfree(name);
1170         if (!res)
1171                 return -EINVAL;
1172
1173         lock_system_sleep();
1174         swsusp_resume_device = res;
1175         unlock_system_sleep();
1176         pm_pr_dbg("Configured hibernation resume from disk to %u\n",
1177                   swsusp_resume_device);
1178         noresume = 0;
1179         software_resume();
1180         return n;
1181 }
1182
1183 power_attr(resume);
1184
1185 static ssize_t resume_offset_show(struct kobject *kobj,
1186                                   struct kobj_attribute *attr, char *buf)
1187 {
1188         return sprintf(buf, "%llu\n", (unsigned long long)swsusp_resume_block);
1189 }
1190
1191 static ssize_t resume_offset_store(struct kobject *kobj,
1192                                    struct kobj_attribute *attr, const char *buf,
1193                                    size_t n)
1194 {
1195         unsigned long long offset;
1196         int rc;
1197
1198         rc = kstrtoull(buf, 0, &offset);
1199         if (rc)
1200                 return rc;
1201         swsusp_resume_block = offset;
1202
1203         return n;
1204 }
1205
1206 power_attr(resume_offset);
1207
1208 static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
1209                                char *buf)
1210 {
1211         return sprintf(buf, "%lu\n", image_size);
1212 }
1213
1214 static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
1215                                 const char *buf, size_t n)
1216 {
1217         unsigned long size;
1218
1219         if (sscanf(buf, "%lu", &size) == 1) {
1220                 image_size = size;
1221                 return n;
1222         }
1223
1224         return -EINVAL;
1225 }
1226
1227 power_attr(image_size);
1228
1229 static ssize_t reserved_size_show(struct kobject *kobj,
1230                                   struct kobj_attribute *attr, char *buf)
1231 {
1232         return sprintf(buf, "%lu\n", reserved_size);
1233 }
1234
1235 static ssize_t reserved_size_store(struct kobject *kobj,
1236                                    struct kobj_attribute *attr,
1237                                    const char *buf, size_t n)
1238 {
1239         unsigned long size;
1240
1241         if (sscanf(buf, "%lu", &size) == 1) {
1242                 reserved_size = size;
1243                 return n;
1244         }
1245
1246         return -EINVAL;
1247 }
1248
1249 power_attr(reserved_size);
1250
1251 static struct attribute *g[] = {
1252         &disk_attr.attr,
1253         &resume_offset_attr.attr,
1254         &resume_attr.attr,
1255         &image_size_attr.attr,
1256         &reserved_size_attr.attr,
1257         NULL,
1258 };
1259
1260
1261 static const struct attribute_group attr_group = {
1262         .attrs = g,
1263 };
1264
1265
1266 static int __init pm_disk_init(void)
1267 {
1268         return sysfs_create_group(power_kobj, &attr_group);
1269 }
1270
1271 core_initcall(pm_disk_init);
1272
1273
1274 static int __init resume_setup(char *str)
1275 {
1276         if (noresume)
1277                 return 1;
1278
1279         strncpy(resume_file, str, 255);
1280         return 1;
1281 }
1282
1283 static int __init resume_offset_setup(char *str)
1284 {
1285         unsigned long long offset;
1286
1287         if (noresume)
1288                 return 1;
1289
1290         if (sscanf(str, "%llu", &offset) == 1)
1291                 swsusp_resume_block = offset;
1292
1293         return 1;
1294 }
1295
1296 static int __init hibernate_setup(char *str)
1297 {
1298         if (!strncmp(str, "noresume", 8)) {
1299                 noresume = 1;
1300         } else if (!strncmp(str, "nocompress", 10)) {
1301                 nocompress = 1;
1302         } else if (!strncmp(str, "no", 2)) {
1303                 noresume = 1;
1304                 nohibernate = 1;
1305         } else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)
1306                    && !strncmp(str, "protect_image", 13)) {
1307                 enable_restore_image_protection();
1308         }
1309         return 1;
1310 }
1311
1312 static int __init noresume_setup(char *str)
1313 {
1314         noresume = 1;
1315         return 1;
1316 }
1317
1318 static int __init resumewait_setup(char *str)
1319 {
1320         resume_wait = 1;
1321         return 1;
1322 }
1323
1324 static int __init resumedelay_setup(char *str)
1325 {
1326         int rc = kstrtouint(str, 0, &resume_delay);
1327
1328         if (rc)
1329                 return rc;
1330         return 1;
1331 }
1332
1333 static int __init nohibernate_setup(char *str)
1334 {
1335         noresume = 1;
1336         nohibernate = 1;
1337         return 1;
1338 }
1339
1340 __setup("noresume", noresume_setup);
1341 __setup("resume_offset=", resume_offset_setup);
1342 __setup("resume=", resume_setup);
1343 __setup("hibernate=", hibernate_setup);
1344 __setup("resumewait", resumewait_setup);
1345 __setup("resumedelay=", resumedelay_setup);
1346 __setup("nohibernate", nohibernate_setup);