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/ktime.h>
  32 #include <linux/security.h>
  33 #include <linux/secretmem.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 &&
  85                 !security_locked_down(LOCKDOWN_HIBERNATION) &&
  86                 !secretmem_active() && !cxl_mem_active();
  87 }
  88
  89 /**
  90  * hibernation_set_ops - Set the global hibernate operations.
  91  * @ops: Hibernation operations to use in subsequent hibernation transitions.
  92  */
  93 void hibernation_set_ops(const struct platform_hibernation_ops *ops)
  94 {
  95         unsigned int sleep_flags;
  96
  97         if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
  98             && ops->prepare && ops->finish && ops->enter && ops->pre_restore
  99             && ops->restore_cleanup && ops->leave)) {
 100                 WARN_ON(1);
 101                 return;
 102         }
 103
 104         sleep_flags = lock_system_sleep();
 105
 106         hibernation_ops = ops;
 107         if (ops)
 108                 hibernation_mode = HIBERNATION_PLATFORM;
 109         else if (hibernation_mode == HIBERNATION_PLATFORM)
 110                 hibernation_mode = HIBERNATION_SHUTDOWN;
 111
 112         unlock_system_sleep(sleep_flags);
 113 }
 114 EXPORT_SYMBOL_GPL(hibernation_set_ops);
 115
 116 static bool entering_platform_hibernation;
 117
 118 bool system_entering_hibernation(void)
 119 {
 120         return entering_platform_hibernation;
 121 }
 122 EXPORT_SYMBOL(system_entering_hibernation);
 123
 124 #ifdef CONFIG_PM_DEBUG
 125 static void hibernation_debug_sleep(void)
 126 {
 127         pr_info("debug: Waiting for 5 seconds.\n");
 128         mdelay(5000);
 129 }
 130
 131 static int hibernation_test(int level)
 132 {
 133         if (pm_test_level == level) {
 134                 hibernation_debug_sleep();
 135                 return 1;
 136         }
 137         return 0;
 138 }
 139 #else /* !CONFIG_PM_DEBUG */
 140 static int hibernation_test(int level) { return 0; }
 141 #endif /* !CONFIG_PM_DEBUG */
 142
 143 /**
 144  * platform_begin - Call platform to start hibernation.
 145  * @platform_mode: Whether or not to use the platform driver.
 146  */
 147 static int platform_begin(int platform_mode)
 148 {
 149         return (platform_mode && hibernation_ops) ?
 150                 hibernation_ops->begin(PMSG_FREEZE) : 0;
 151 }
 152
 153 /**
 154  * platform_end - Call platform to finish transition to the working state.
 155  * @platform_mode: Whether or not to use the platform driver.
 156  */
 157 static void platform_end(int platform_mode)
 158 {
 159         if (platform_mode && hibernation_ops)
 160                 hibernation_ops->end();
 161 }
 162
 163 /**
 164  * platform_pre_snapshot - Call platform to prepare the machine for hibernation.
 165  * @platform_mode: Whether or not to use the platform driver.
 166  *
 167  * Use the platform driver to prepare the system for creating a hibernate image,
 168  * if so configured, and return an error code if that fails.
 169  */
 170
 171 static int platform_pre_snapshot(int platform_mode)
 172 {
 173         return (platform_mode && hibernation_ops) ?
 174                 hibernation_ops->pre_snapshot() : 0;
 175 }
 176
 177 /**
 178  * platform_leave - Call platform to prepare a transition to the working state.
 179  * @platform_mode: Whether or not to use the platform driver.
 180  *
 181  * Use the platform driver prepare to prepare the machine for switching to the
 182  * normal mode of operation.
 183  *
 184  * This routine is called on one CPU with interrupts disabled.
 185  */
 186 static void platform_leave(int platform_mode)
 187 {
 188         if (platform_mode && hibernation_ops)
 189                 hibernation_ops->leave();
 190 }
 191
 192 /**
 193  * platform_finish - Call platform to switch the system to the working state.
 194  * @platform_mode: Whether or not to use the platform driver.
 195  *
 196  * Use the platform driver to switch the machine to the normal mode of
 197  * operation.
 198  *
 199  * This routine must be called after platform_prepare().
 200  */
 201 static void platform_finish(int platform_mode)
 202 {
 203         if (platform_mode && hibernation_ops)
 204                 hibernation_ops->finish();
 205 }
 206
 207 /**
 208  * platform_pre_restore - Prepare for hibernate image restoration.
 209  * @platform_mode: Whether or not to use the platform driver.
 210  *
 211  * Use the platform driver to prepare the system for resume from a hibernation
 212  * image.
 213  *
 214  * If the restore fails after this function has been called,
 215  * platform_restore_cleanup() must be called.
 216  */
 217 static int platform_pre_restore(int platform_mode)
 218 {
 219         return (platform_mode && hibernation_ops) ?
 220                 hibernation_ops->pre_restore() : 0;
 221 }
 222
 223 /**
 224  * platform_restore_cleanup - Switch to the working state after failing restore.
 225  * @platform_mode: Whether or not to use the platform driver.
 226  *
 227  * Use the platform driver to switch the system to the normal mode of operation
 228  * after a failing restore.
 229  *
 230  * If platform_pre_restore() has been called before the failing restore, this
 231  * function must be called too, regardless of the result of
 232  * platform_pre_restore().
 233  */
 234 static void platform_restore_cleanup(int platform_mode)
 235 {
 236         if (platform_mode && hibernation_ops)
 237                 hibernation_ops->restore_cleanup();
 238 }
 239
 240 /**
 241  * platform_recover - Recover from a failure to suspend devices.
 242  * @platform_mode: Whether or not to use the platform driver.
 243  */
 244 static void platform_recover(int platform_mode)
 245 {
 246         if (platform_mode && hibernation_ops && hibernation_ops->recover)
 247                 hibernation_ops->recover();
 248 }
 249
 250 /**
 251  * swsusp_show_speed - Print time elapsed between two events during hibernation.
 252  * @start: Starting event.
 253  * @stop: Final event.
 254  * @nr_pages: Number of memory pages processed between @start and @stop.
 255  * @msg: Additional diagnostic message to print.
 256  */
 257 void swsusp_show_speed(ktime_t start, ktime_t stop,
 258                       unsigned nr_pages, char *msg)
 259 {
 260         ktime_t diff;
 261         u64 elapsed_centisecs64;
 262         unsigned int centisecs;
 263         unsigned int k;
 264         unsigned int kps;
 265
 266         diff = ktime_sub(stop, start);
 267         elapsed_centisecs64 = ktime_divns(diff, 10*NSEC_PER_MSEC);
 268         centisecs = elapsed_centisecs64;
 269         if (centisecs == 0)
 270                 centisecs = 1;  /* avoid div-by-zero */
 271         k = nr_pages * (PAGE_SIZE / 1024);
 272         kps = (k * 100) / centisecs;
 273         pr_info("%s %u kbytes in %u.%02u seconds (%u.%02u MB/s)\n",
 274                 msg, k, centisecs / 100, centisecs % 100, kps / 1000,
 275                 (kps % 1000) / 10);
 276 }
 277
 278 __weak int arch_resume_nosmt(void)
 279 {
 280         return 0;
 281 }
 282
 283 /**
 284  * create_image - Create a hibernation image.
 285  * @platform_mode: Whether or not to use the platform driver.
 286  *
 287  * Execute device drivers' "late" and "noirq" freeze callbacks, create a
 288  * hibernation image and run the drivers' "noirq" and "early" thaw callbacks.
 289  *
 290  * Control reappears in this routine after the subsequent restore.
 291  */
 292 static int create_image(int platform_mode)
 293 {
 294         int error;
 295
 296         error = dpm_suspend_end(PMSG_FREEZE);
 297         if (error) {
 298                 pr_err("Some devices failed to power down, aborting\n");
 299                 return error;
 300         }
 301
 302         error = platform_pre_snapshot(platform_mode);
 303         if (error || hibernation_test(TEST_PLATFORM))
 304                 goto Platform_finish;
 305
 306         error = pm_sleep_disable_secondary_cpus();
 307         if (error || hibernation_test(TEST_CPUS))
 308                 goto Enable_cpus;
 309
 310         local_irq_disable();
 311
 312         system_state = SYSTEM_SUSPEND;
 313
 314         error = syscore_suspend();
 315         if (error) {
 316                 pr_err("Some system devices failed to power down, aborting\n");
 317                 goto Enable_irqs;
 318         }
 319
 320         if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
 321                 goto Power_up;
 322
 323         in_suspend = 1;
 324         save_processor_state();
 325         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);
 326         error = swsusp_arch_suspend();
 327         /* Restore control flow magically appears here */
 328         restore_processor_state();
 329         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
 330         if (error)
 331                 pr_err("Error %d creating image\n", error);
 332
 333         if (!in_suspend) {
 334                 events_check_enabled = false;
 335                 clear_or_poison_free_pages();
 336         }
 337
 338         platform_leave(platform_mode);
 339
 340  Power_up:
 341         syscore_resume();
 342
 343  Enable_irqs:
 344         system_state = SYSTEM_RUNNING;
 345         local_irq_enable();
 346
 347  Enable_cpus:
 348         pm_sleep_enable_secondary_cpus();
 349
 350         /* Allow architectures to do nosmt-specific post-resume dances */
 351         if (!in_suspend)
 352                 error = arch_resume_nosmt();
 353
 354  Platform_finish:
 355         platform_finish(platform_mode);
 356
 357         dpm_resume_start(in_suspend ?
 358                 (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
 359
 360         return error;
 361 }
 362
 363 /**
 364  * hibernation_snapshot - Quiesce devices and create a hibernation image.
 365  * @platform_mode: If set, use platform driver to prepare for the transition.
 366  *
 367  * This routine must be called with system_transition_mutex held.
 368  */
 369 int hibernation_snapshot(int platform_mode)
 370 {
 371         pm_message_t msg;
 372         int error;
 373
 374         pm_suspend_clear_flags();
 375         error = platform_begin(platform_mode);
 376         if (error)
 377                 goto Close;
 378
 379         /* Preallocate image memory before shutting down devices. */
 380         error = hibernate_preallocate_memory();
 381         if (error)
 382                 goto Close;
 383
 384         error = freeze_kernel_threads();
 385         if (error)
 386                 goto Cleanup;
 387
 388         if (hibernation_test(TEST_FREEZER)) {
 389
 390                 /*
 391                  * Indicate to the caller that we are returning due to a
 392                  * successful freezer test.
 393                  */
 394                 freezer_test_done = true;
 395                 goto Thaw;
 396         }
 397
 398         error = dpm_prepare(PMSG_FREEZE);
 399         if (error) {
 400                 dpm_complete(PMSG_RECOVER);
 401                 goto Thaw;
 402         }
 403
 404         suspend_console();
 405         pm_restrict_gfp_mask();
 406
 407         error = dpm_suspend(PMSG_FREEZE);
 408
 409         if (error || hibernation_test(TEST_DEVICES))
 410                 platform_recover(platform_mode);
 411         else
 412                 error = create_image(platform_mode);
 413
 414         /*
 415          * In the case that we call create_image() above, the control
 416          * returns here (1) after the image has been created or the
 417          * image creation has failed and (2) after a successful restore.
 418          */
 419
 420         /* We may need to release the preallocated image pages here. */
 421         if (error || !in_suspend)
 422                 swsusp_free();
 423
 424         msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
 425         dpm_resume(msg);
 426
 427         if (error || !in_suspend)
 428                 pm_restore_gfp_mask();
 429
 430         resume_console();
 431         dpm_complete(msg);
 432
 433  Close:
 434         platform_end(platform_mode);
 435         return error;
 436
 437  Thaw:
 438         thaw_kernel_threads();
 439  Cleanup:
 440         swsusp_free();
 441         goto Close;
 442 }
 443
 444 int __weak hibernate_resume_nonboot_cpu_disable(void)
 445 {
 446         return suspend_disable_secondary_cpus();
 447 }
 448
 449 /**
 450  * resume_target_kernel - Restore system state from a hibernation image.
 451  * @platform_mode: Whether or not to use the platform driver.
 452  *
 453  * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
 454  * contents of highmem that have not been restored yet from the image and run
 455  * the low-level code that will restore the remaining contents of memory and
 456  * switch to the just restored target kernel.
 457  */
 458 static int resume_target_kernel(bool platform_mode)
 459 {
 460         int error;
 461
 462         error = dpm_suspend_end(PMSG_QUIESCE);
 463         if (error) {
 464                 pr_err("Some devices failed to power down, aborting resume\n");
 465                 return error;
 466         }
 467
 468         error = platform_pre_restore(platform_mode);
 469         if (error)
 470                 goto Cleanup;
 471
 472         cpuidle_pause();
 473
 474         error = hibernate_resume_nonboot_cpu_disable();
 475         if (error)
 476                 goto Enable_cpus;
 477
 478         local_irq_disable();
 479         system_state = SYSTEM_SUSPEND;
 480
 481         error = syscore_suspend();
 482         if (error)
 483                 goto Enable_irqs;
 484
 485         save_processor_state();
 486         error = restore_highmem();
 487         if (!error) {
 488                 error = swsusp_arch_resume();
 489                 /*
 490                  * The code below is only ever reached in case of a failure.
 491                  * Otherwise, execution continues at the place where
 492                  * swsusp_arch_suspend() was called.
 493                  */
 494                 BUG_ON(!error);
 495                 /*
 496                  * This call to restore_highmem() reverts the changes made by
 497                  * the previous one.
 498                  */
 499                 restore_highmem();
 500         }
 501         /*
 502          * The only reason why swsusp_arch_resume() can fail is memory being
 503          * very tight, so we have to free it as soon as we can to avoid
 504          * subsequent failures.
 505          */
 506         swsusp_free();
 507         restore_processor_state();
 508         touch_softlockup_watchdog();
 509
 510         syscore_resume();
 511
 512  Enable_irqs:
 513         system_state = SYSTEM_RUNNING;
 514         local_irq_enable();
 515
 516  Enable_cpus:
 517         pm_sleep_enable_secondary_cpus();
 518
 519  Cleanup:
 520         platform_restore_cleanup(platform_mode);
 521
 522         dpm_resume_start(PMSG_RECOVER);
 523
 524         return error;
 525 }
 526
 527 /**
 528  * hibernation_restore - Quiesce devices and restore from a hibernation image.
 529  * @platform_mode: If set, use platform driver to prepare for the transition.
 530  *
 531  * This routine must be called with system_transition_mutex held.  If it is
 532  * successful, control reappears in the restored target kernel in
 533  * hibernation_snapshot().
 534  */
 535 int hibernation_restore(int platform_mode)
 536 {
 537         int error;
 538
 539         pm_prepare_console();
 540         suspend_console();
 541         pm_restrict_gfp_mask();
 542         error = dpm_suspend_start(PMSG_QUIESCE);
 543         if (!error) {
 544                 error = resume_target_kernel(platform_mode);
 545                 /*
 546                  * The above should either succeed and jump to the new kernel,
 547                  * or return with an error. Otherwise things are just
 548                  * undefined, so let's be paranoid.
 549                  */
 550                 BUG_ON(!error);
 551         }
 552         dpm_resume_end(PMSG_RECOVER);
 553         pm_restore_gfp_mask();
 554         resume_console();
 555         pm_restore_console();
 556         return error;
 557 }
 558
 559 /**
 560  * hibernation_platform_enter - Power off the system using the platform driver.
 561  */
 562 int hibernation_platform_enter(void)
 563 {
 564         int error;
 565
 566         if (!hibernation_ops)
 567                 return -ENOSYS;
 568
 569         /*
 570          * We have cancelled the power transition by running
 571          * hibernation_ops->finish() before saving the image, so we should let
 572          * the firmware know that we're going to enter the sleep state after all
 573          */
 574         error = hibernation_ops->begin(PMSG_HIBERNATE);
 575         if (error)
 576                 goto Close;
 577
 578         entering_platform_hibernation = true;
 579         suspend_console();
 580         error = dpm_suspend_start(PMSG_HIBERNATE);
 581         if (error) {
 582                 if (hibernation_ops->recover)
 583                         hibernation_ops->recover();
 584                 goto Resume_devices;
 585         }
 586
 587         error = dpm_suspend_end(PMSG_HIBERNATE);
 588         if (error)
 589                 goto Resume_devices;
 590
 591         error = hibernation_ops->prepare();
 592         if (error)
 593                 goto Platform_finish;
 594
 595         error = pm_sleep_disable_secondary_cpus();
 596         if (error)
 597                 goto Enable_cpus;
 598
 599         local_irq_disable();
 600         system_state = SYSTEM_SUSPEND;
 601         syscore_suspend();
 602         if (pm_wakeup_pending()) {
 603                 error = -EAGAIN;
 604                 goto Power_up;
 605         }
 606
 607         hibernation_ops->enter();
 608         /* We should never get here */
 609         while (1);
 610
 611  Power_up:
 612         syscore_resume();
 613         system_state = SYSTEM_RUNNING;
 614         local_irq_enable();
 615
 616  Enable_cpus:
 617         pm_sleep_enable_secondary_cpus();
 618
 619  Platform_finish:
 620         hibernation_ops->finish();
 621
 622         dpm_resume_start(PMSG_RESTORE);
 623
 624  Resume_devices:
 625         entering_platform_hibernation = false;
 626         dpm_resume_end(PMSG_RESTORE);
 627         resume_console();
 628
 629  Close:
 630         hibernation_ops->end();
 631
 632         return error;
 633 }
 634
 635 /**
 636  * power_down - Shut the machine down for hibernation.
 637  *
 638  * Use the platform driver, if configured, to put the system into the sleep
 639  * state corresponding to hibernation, or try to power it off or reboot,
 640  * depending on the value of hibernation_mode.
 641  */
 642 static void power_down(void)
 643 {
 644 #ifdef CONFIG_SUSPEND
 645         int error;
 646
 647         if (hibernation_mode == HIBERNATION_SUSPEND) {
 648                 error = suspend_devices_and_enter(mem_sleep_current);
 649                 if (error) {
 650                         hibernation_mode = hibernation_ops ?
 651                                                 HIBERNATION_PLATFORM :
 652                                                 HIBERNATION_SHUTDOWN;
 653                 } else {
 654                         /* Restore swap signature. */
 655                         error = swsusp_unmark();
 656                         if (error)
 657                                 pr_err("Swap will be unusable! Try swapon -a.\n");
 658
 659                         return;
 660                 }
 661         }
 662 #endif
 663
 664         switch (hibernation_mode) {
 665         case HIBERNATION_REBOOT:
 666                 kernel_restart(NULL);
 667                 break;
 668         case HIBERNATION_PLATFORM:
 669                 hibernation_platform_enter();
 670                 fallthrough;
 671         case HIBERNATION_SHUTDOWN:
 672                 if (kernel_can_power_off())
 673                         kernel_power_off();
 674                 break;
 675         }
 676         kernel_halt();
 677         /*
 678          * Valid image is on the disk, if we continue we risk serious data
 679          * corruption after resume.
 680          */
 681         pr_crit("Power down manually\n");
 682         while (1)
 683                 cpu_relax();
 684 }
 685
 686 static int load_image_and_restore(void)
 687 {
 688         int error;
 689         unsigned int flags;
 690
 691         pm_pr_dbg("Loading hibernation image.\n");
 692
 693         lock_device_hotplug();
 694         error = create_basic_memory_bitmaps();
 695         if (error) {
 696                 swsusp_close(FMODE_READ | FMODE_EXCL);
 697                 goto Unlock;
 698         }
 699
 700         error = swsusp_read(&flags);
 701         swsusp_close(FMODE_READ | FMODE_EXCL);
 702         if (!error)
 703                 error = hibernation_restore(flags & SF_PLATFORM_MODE);
 704
 705         pr_err("Failed to load image, recovering.\n");
 706         swsusp_free();
 707         free_basic_memory_bitmaps();
 708  Unlock:
 709         unlock_device_hotplug();
 710
 711         return error;
 712 }
 713
 714 /**
 715  * hibernate - Carry out system hibernation, including saving the image.
 716  */
 717 int hibernate(void)
 718 {
 719         bool snapshot_test = false;
 720         unsigned int sleep_flags;
 721         int error;
 722
 723         if (!hibernation_available()) {
 724                 pm_pr_dbg("Hibernation not available.\n");
 725                 return -EPERM;
 726         }
 727
 728         sleep_flags = lock_system_sleep();
 729         /* The snapshot device should not be opened while we're running */
 730         if (!hibernate_acquire()) {
 731                 error = -EBUSY;
 732                 goto Unlock;
 733         }
 734
 735         pr_info("hibernation entry\n");
 736         pm_prepare_console();
 737         error = pm_notifier_call_chain_robust(PM_HIBERNATION_PREPARE, PM_POST_HIBERNATION);
 738         if (error)
 739                 goto Restore;
 740
 741         ksys_sync_helper();
 742
 743         error = freeze_processes();
 744         if (error)
 745                 goto Exit;
 746
 747         lock_device_hotplug();
 748         /* Allocate memory management structures */
 749         error = create_basic_memory_bitmaps();
 750         if (error)
 751                 goto Thaw;
 752
 753         error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
 754         if (error || freezer_test_done)
 755                 goto Free_bitmaps;
 756
 757         if (in_suspend) {
 758                 unsigned int flags = 0;
 759
 760                 if (hibernation_mode == HIBERNATION_PLATFORM)
 761                         flags |= SF_PLATFORM_MODE;
 762                 if (nocompress)
 763                         flags |= SF_NOCOMPRESS_MODE;
 764                 else
 765                         flags |= SF_CRC32_MODE;
 766
 767                 pm_pr_dbg("Writing hibernation image.\n");
 768                 error = swsusp_write(flags);
 769                 swsusp_free();
 770                 if (!error) {
 771                         if (hibernation_mode == HIBERNATION_TEST_RESUME)
 772                                 snapshot_test = true;
 773                         else
 774                                 power_down();
 775                 }
 776                 in_suspend = 0;
 777                 pm_restore_gfp_mask();
 778         } else {
 779                 pm_pr_dbg("Hibernation image restored successfully.\n");
 780         }
 781
 782  Free_bitmaps:
 783         free_basic_memory_bitmaps();
 784  Thaw:
 785         unlock_device_hotplug();
 786         if (snapshot_test) {
 787                 pm_pr_dbg("Checking hibernation image\n");
 788                 error = swsusp_check();
 789                 if (!error)
 790                         error = load_image_and_restore();
 791         }
 792         thaw_processes();
 793
 794         /* Don't bother checking whether freezer_test_done is true */
 795         freezer_test_done = false;
 796  Exit:
 797         pm_notifier_call_chain(PM_POST_HIBERNATION);
 798  Restore:
 799         pm_restore_console();
 800         hibernate_release();
 801  Unlock:
 802         unlock_system_sleep(sleep_flags);
 803         pr_info("hibernation exit\n");
 804
 805         return error;
 806 }
 807
 808 /**
 809  * hibernate_quiet_exec - Execute a function with all devices frozen.
 810  * @func: Function to execute.
 811  * @data: Data pointer to pass to @func.
 812  *
 813  * Return the @func return value or an error code if it cannot be executed.
 814  */
 815 int hibernate_quiet_exec(int (*func)(void *data), void *data)
 816 {
 817         unsigned int sleep_flags;
 818         int error;
 819
 820         sleep_flags = lock_system_sleep();
 821
 822         if (!hibernate_acquire()) {
 823                 error = -EBUSY;
 824                 goto unlock;
 825         }
 826
 827         pm_prepare_console();
 828
 829         error = pm_notifier_call_chain_robust(PM_HIBERNATION_PREPARE, PM_POST_HIBERNATION);
 830         if (error)
 831                 goto restore;
 832
 833         error = freeze_processes();
 834         if (error)
 835                 goto exit;
 836
 837         lock_device_hotplug();
 838
 839         pm_suspend_clear_flags();
 840
 841         error = platform_begin(true);
 842         if (error)
 843                 goto thaw;
 844
 845         error = freeze_kernel_threads();
 846         if (error)
 847                 goto thaw;
 848
 849         error = dpm_prepare(PMSG_FREEZE);
 850         if (error)
 851                 goto dpm_complete;
 852
 853         suspend_console();
 854
 855         error = dpm_suspend(PMSG_FREEZE);
 856         if (error)
 857                 goto dpm_resume;
 858
 859         error = dpm_suspend_end(PMSG_FREEZE);
 860         if (error)
 861                 goto dpm_resume;
 862
 863         error = platform_pre_snapshot(true);
 864         if (error)
 865                 goto skip;
 866
 867         error = func(data);
 868
 869 skip:
 870         platform_finish(true);
 871
 872         dpm_resume_start(PMSG_THAW);
 873
 874 dpm_resume:
 875         dpm_resume(PMSG_THAW);
 876
 877         resume_console();
 878
 879 dpm_complete:
 880         dpm_complete(PMSG_THAW);
 881
 882         thaw_kernel_threads();
 883
 884 thaw:
 885         platform_end(true);
 886
 887         unlock_device_hotplug();
 888
 889         thaw_processes();
 890
 891 exit:
 892         pm_notifier_call_chain(PM_POST_HIBERNATION);
 893
 894 restore:
 895         pm_restore_console();
 896
 897         hibernate_release();
 898
 899 unlock:
 900         unlock_system_sleep(sleep_flags);
 901
 902         return error;
 903 }
 904 EXPORT_SYMBOL_GPL(hibernate_quiet_exec);
 905
 906 /**
 907  * software_resume - Resume from a saved hibernation image.
 908  *
 909  * This routine is called as a late initcall, when all devices have been
 910  * discovered and initialized already.
 911  *
 912  * The image reading code is called to see if there is a hibernation image
 913  * available for reading.  If that is the case, devices are quiesced and the
 914  * contents of memory is restored from the saved image.
 915  *
 916  * If this is successful, control reappears in the restored target kernel in
 917  * hibernation_snapshot() which returns to hibernate().  Otherwise, the routine
 918  * attempts to recover gracefully and make the kernel return to the normal mode
 919  * of operation.
 920  */
 921 static int software_resume(void)
 922 {
 923         int error;
 924
 925         /*
 926          * If the user said "noresume".. bail out early.
 927          */
 928         if (noresume || !hibernation_available())
 929                 return 0;
 930
 931         /*
 932          * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
 933          * is configured into the kernel. Since the regular hibernate
 934          * trigger path is via sysfs which takes a buffer mutex before
 935          * calling hibernate functions (which take system_transition_mutex)
 936          * this can cause lockdep to complain about a possible ABBA deadlock
 937          * which cannot happen since we're in the boot code here and
 938          * sysfs can't be invoked yet. Therefore, we use a subclass
 939          * here to avoid lockdep complaining.
 940          */
 941         mutex_lock_nested(&system_transition_mutex, SINGLE_DEPTH_NESTING);
 942
 943         if (swsusp_resume_device)
 944                 goto Check_image;
 945
 946         if (!strlen(resume_file)) {
 947                 error = -ENOENT;
 948                 goto Unlock;
 949         }
 950
 951         pm_pr_dbg("Checking hibernation image partition %s\n", resume_file);
 952
 953         if (resume_delay) {
 954                 pr_info("Waiting %dsec before reading resume device ...\n",
 955                         resume_delay);
 956                 ssleep(resume_delay);
 957         }
 958
 959         /* Check if the device is there */
 960         swsusp_resume_device = name_to_dev_t(resume_file);
 961         if (!swsusp_resume_device) {
 962                 /*
 963                  * Some device discovery might still be in progress; we need
 964                  * to wait for this to finish.
 965                  */
 966                 wait_for_device_probe();
 967
 968                 if (resume_wait) {
 969                         while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
 970                                 msleep(10);
 971                         async_synchronize_full();
 972                 }
 973
 974                 swsusp_resume_device = name_to_dev_t(resume_file);
 975                 if (!swsusp_resume_device) {
 976                         error = -ENODEV;
 977                         goto Unlock;
 978                 }
 979         }
 980
 981  Check_image:
 982         pm_pr_dbg("Hibernation image partition %d:%d present\n",
 983                 MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 984
 985         pm_pr_dbg("Looking for hibernation image.\n");
 986         error = swsusp_check();
 987         if (error)
 988                 goto Unlock;
 989
 990         /* The snapshot device should not be opened while we're running */
 991         if (!hibernate_acquire()) {
 992                 error = -EBUSY;
 993                 swsusp_close(FMODE_READ | FMODE_EXCL);
 994                 goto Unlock;
 995         }
 996
 997         pr_info("resume from hibernation\n");
 998         pm_prepare_console();
 999         error = pm_notifier_call_chain_robust(PM_RESTORE_PREPARE, PM_POST_RESTORE);
1000         if (error)
1001                 goto Restore;
1002
1003         pm_pr_dbg("Preparing processes for hibernation restore.\n");
1004         error = freeze_processes();
1005         if (error)
1006                 goto Close_Finish;
1007
1008         error = freeze_kernel_threads();
1009         if (error) {
1010                 thaw_processes();
1011                 goto Close_Finish;
1012         }
1013
1014         error = load_image_and_restore();
1015         thaw_processes();
1016  Finish:
1017         pm_notifier_call_chain(PM_POST_RESTORE);
1018  Restore:
1019         pm_restore_console();
1020         pr_info("resume failed (%d)\n", error);
1021         hibernate_release();
1022         /* For success case, the suspend path will release the lock */
1023  Unlock:
1024         mutex_unlock(&system_transition_mutex);
1025         pm_pr_dbg("Hibernation image not present or could not be loaded.\n");
1026         return error;
1027  Close_Finish:
1028         swsusp_close(FMODE_READ | FMODE_EXCL);
1029         goto Finish;
1030 }
1031
1032 late_initcall_sync(software_resume);
1033
1034
1035 static const char * const hibernation_modes[] = {
1036         [HIBERNATION_PLATFORM]  = "platform",
1037         [HIBERNATION_SHUTDOWN]  = "shutdown",
1038         [HIBERNATION_REBOOT]    = "reboot",
1039 #ifdef CONFIG_SUSPEND
1040         [HIBERNATION_SUSPEND]   = "suspend",
1041 #endif
1042         [HIBERNATION_TEST_RESUME]       = "test_resume",
1043 };
1044
1045 /*
1046  * /sys/power/disk - Control hibernation mode.
1047  *
1048  * Hibernation can be handled in several ways.  There are a few different ways
1049  * to put the system into the sleep state: using the platform driver (e.g. ACPI
1050  * or other hibernation_ops), powering it off or rebooting it (for testing
1051  * mostly).
1052  *
1053  * The sysfs file /sys/power/disk provides an interface for selecting the
1054  * hibernation mode to use.  Reading from this file causes the available modes
1055  * to be printed.  There are 3 modes that can be supported:
1056  *
1057  *      'platform'
1058  *      'shutdown'
1059  *      'reboot'
1060  *
1061  * If a platform hibernation driver is in use, 'platform' will be supported
1062  * and will be used by default.  Otherwise, 'shutdown' will be used by default.
1063  * The selected option (i.e. the one corresponding to the current value of
1064  * hibernation_mode) is enclosed by a square bracket.
1065  *
1066  * To select a given hibernation mode it is necessary to write the mode's
1067  * string representation (as returned by reading from /sys/power/disk) back
1068  * into /sys/power/disk.
1069  */
1070
1071 static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
1072                          char *buf)
1073 {
1074         int i;
1075         char *start = buf;
1076
1077         if (!hibernation_available())
1078                 return sprintf(buf, "[disabled]\n");
1079
1080         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
1081                 if (!hibernation_modes[i])
1082                         continue;
1083                 switch (i) {
1084                 case HIBERNATION_SHUTDOWN:
1085                 case HIBERNATION_REBOOT:
1086 #ifdef CONFIG_SUSPEND
1087                 case HIBERNATION_SUSPEND:
1088 #endif
1089                 case HIBERNATION_TEST_RESUME:
1090                         break;
1091                 case HIBERNATION_PLATFORM:
1092                         if (hibernation_ops)
1093                                 break;
1094                         /* not a valid mode, continue with loop */
1095                         continue;
1096                 }
1097                 if (i == hibernation_mode)
1098                         buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
1099                 else
1100                         buf += sprintf(buf, "%s ", hibernation_modes[i]);
1101         }
1102         buf += sprintf(buf, "\n");
1103         return buf-start;
1104 }
1105
1106 static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
1107                           const char *buf, size_t n)
1108 {
1109         int mode = HIBERNATION_INVALID;
1110         unsigned int sleep_flags;
1111         int error = 0;
1112         int len;
1113         char *p;
1114         int i;
1115
1116         if (!hibernation_available())
1117                 return -EPERM;
1118
1119         p = memchr(buf, '\n', n);
1120         len = p ? p - buf : n;
1121
1122         sleep_flags = lock_system_sleep();
1123         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
1124                 if (len == strlen(hibernation_modes[i])
1125                     && !strncmp(buf, hibernation_modes[i], len)) {
1126                         mode = i;
1127                         break;
1128                 }
1129         }
1130         if (mode != HIBERNATION_INVALID) {
1131                 switch (mode) {
1132                 case HIBERNATION_SHUTDOWN:
1133                 case HIBERNATION_REBOOT:
1134 #ifdef CONFIG_SUSPEND
1135                 case HIBERNATION_SUSPEND:
1136 #endif
1137                 case HIBERNATION_TEST_RESUME:
1138                         hibernation_mode = mode;
1139                         break;
1140                 case HIBERNATION_PLATFORM:
1141                         if (hibernation_ops)
1142                                 hibernation_mode = mode;
1143                         else
1144                                 error = -EINVAL;
1145                 }
1146         } else
1147                 error = -EINVAL;
1148
1149         if (!error)
1150                 pm_pr_dbg("Hibernation mode set to '%s'\n",
1151                                hibernation_modes[mode]);
1152         unlock_system_sleep(sleep_flags);
1153         return error ? error : n;
1154 }
1155
1156 power_attr(disk);
1157
1158 static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
1159                            char *buf)
1160 {
1161         return sprintf(buf, "%d:%d\n", MAJOR(swsusp_resume_device),
1162                        MINOR(swsusp_resume_device));
1163 }
1164
1165 static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
1166                             const char *buf, size_t n)
1167 {
1168         unsigned int sleep_flags;
1169         int len = n;
1170         char *name;
1171         dev_t res;
1172
1173         if (len && buf[len-1] == '\n')
1174                 len--;
1175         name = kstrndup(buf, len, GFP_KERNEL);
1176         if (!name)
1177                 return -ENOMEM;
1178
1179         res = name_to_dev_t(name);
1180         kfree(name);
1181         if (!res)
1182                 return -EINVAL;
1183
1184         sleep_flags = lock_system_sleep();
1185         swsusp_resume_device = res;
1186         unlock_system_sleep(sleep_flags);
1187
1188         pm_pr_dbg("Configured hibernation resume from disk to %u\n",
1189                   swsusp_resume_device);
1190         noresume = 0;
1191         software_resume();
1192         return n;
1193 }
1194
1195 power_attr(resume);
1196
1197 static ssize_t resume_offset_show(struct kobject *kobj,
1198                                   struct kobj_attribute *attr, char *buf)
1199 {
1200         return sprintf(buf, "%llu\n", (unsigned long long)swsusp_resume_block);
1201 }
1202
1203 static ssize_t resume_offset_store(struct kobject *kobj,
1204                                    struct kobj_attribute *attr, const char *buf,
1205                                    size_t n)
1206 {
1207         unsigned long long offset;
1208         int rc;
1209
1210         rc = kstrtoull(buf, 0, &offset);
1211         if (rc)
1212                 return rc;
1213         swsusp_resume_block = offset;
1214
1215         return n;
1216 }
1217
1218 power_attr(resume_offset);
1219
1220 static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
1221                                char *buf)
1222 {
1223         return sprintf(buf, "%lu\n", image_size);
1224 }
1225
1226 static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
1227                                 const char *buf, size_t n)
1228 {
1229         unsigned long size;
1230
1231         if (sscanf(buf, "%lu", &size) == 1) {
1232                 image_size = size;
1233                 return n;
1234         }
1235
1236         return -EINVAL;
1237 }
1238
1239 power_attr(image_size);
1240
1241 static ssize_t reserved_size_show(struct kobject *kobj,
1242                                   struct kobj_attribute *attr, char *buf)
1243 {
1244         return sprintf(buf, "%lu\n", reserved_size);
1245 }
1246
1247 static ssize_t reserved_size_store(struct kobject *kobj,
1248                                    struct kobj_attribute *attr,
1249                                    const char *buf, size_t n)
1250 {
1251         unsigned long size;
1252
1253         if (sscanf(buf, "%lu", &size) == 1) {
1254                 reserved_size = size;
1255                 return n;
1256         }
1257
1258         return -EINVAL;
1259 }
1260
1261 power_attr(reserved_size);
1262
1263 static struct attribute *g[] = {
1264         &disk_attr.attr,
1265         &resume_offset_attr.attr,
1266         &resume_attr.attr,
1267         &image_size_attr.attr,
1268         &reserved_size_attr.attr,
1269         NULL,
1270 };
1271
1272
1273 static const struct attribute_group attr_group = {
1274         .attrs = g,
1275 };
1276
1277
1278 static int __init pm_disk_init(void)
1279 {
1280         return sysfs_create_group(power_kobj, &attr_group);
1281 }
1282
1283 core_initcall(pm_disk_init);
1284
1285
1286 static int __init resume_setup(char *str)
1287 {
1288         if (noresume)
1289                 return 1;
1290
1291         strncpy(resume_file, str, 255);
1292         return 1;
1293 }
1294
1295 static int __init resume_offset_setup(char *str)
1296 {
1297         unsigned long long offset;
1298
1299         if (noresume)
1300                 return 1;
1301
1302         if (sscanf(str, "%llu", &offset) == 1)
1303                 swsusp_resume_block = offset;
1304
1305         return 1;
1306 }
1307
1308 static int __init hibernate_setup(char *str)
1309 {
1310         if (!strncmp(str, "noresume", 8)) {
1311                 noresume = 1;
1312         } else if (!strncmp(str, "nocompress", 10)) {
1313                 nocompress = 1;
1314         } else if (!strncmp(str, "no", 2)) {
1315                 noresume = 1;
1316                 nohibernate = 1;
1317         } else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)
1318                    && !strncmp(str, "protect_image", 13)) {
1319                 enable_restore_image_protection();
1320         }
1321         return 1;
1322 }
1323
1324 static int __init noresume_setup(char *str)
1325 {
1326         noresume = 1;
1327         return 1;
1328 }
1329
1330 static int __init resumewait_setup(char *str)
1331 {
1332         resume_wait = 1;
1333         return 1;
1334 }
1335
1336 static int __init resumedelay_setup(char *str)
1337 {
1338         int rc = kstrtouint(str, 0, &resume_delay);
1339
1340         if (rc)
1341                 pr_warn("resumedelay: bad option string '%s'\n", str);
1342         return 1;
1343 }
1344
1345 static int __init nohibernate_setup(char *str)
1346 {
1347         noresume = 1;
1348         nohibernate = 1;
1349         return 1;
1350 }
1351
1352 __setup("noresume", noresume_setup);
1353 __setup("resume_offset=", resume_offset_setup);
1354 __setup("resume=", resume_setup);
1355 __setup("hibernate=", hibernate_setup);
1356 __setup("resumewait", resumewait_setup);
1357 __setup("resumedelay=", resumedelay_setup);
1358 __setup("nohibernate", nohibernate_setup);