kernel/power/hibernate.c

   1 /*
   2  * kernel/power/hibernate.c - Hibernation (a.k.a suspend-to-disk) support.
   3  *
   4  * Copyright (c) 2003 Patrick Mochel
   5  * Copyright (c) 2003 Open Source Development Lab
   6  * Copyright (c) 2004 Pavel Machek <pavel@ucw.cz>
   7  * Copyright (c) 2009 Rafael J. Wysocki, Novell Inc.
   8  * Copyright (C) 2012 Bojan Smojver <bojan@rexursive.com>
   9  *
  10  * This file is released under the GPLv2.
  11  */
  12
  13 #define pr_fmt(fmt) "PM: " fmt
  14
  15 #include <linux/export.h>
  16 #include <linux/suspend.h>
  17 #include <linux/syscalls.h>
  18 #include <linux/reboot.h>
  19 #include <linux/string.h>
  20 #include <linux/device.h>
  21 #include <linux/async.h>
  22 #include <linux/delay.h>
  23 #include <linux/fs.h>
  24 #include <linux/mount.h>
  25 #include <linux/pm.h>
  26 #include <linux/nmi.h>
  27 #include <linux/console.h>
  28 #include <linux/cpu.h>
  29 #include <linux/freezer.h>
  30 #include <linux/gfp.h>
  31 #include <linux/syscore_ops.h>
  32 #include <linux/ctype.h>
  33 #include <linux/genhd.h>
  34 #include <linux/ktime.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 bool hibernation_available(void)
  72 {
  73         return (nohibernate == 0);
  74 }
  75
  76 /**
  77  * hibernation_set_ops - Set the global hibernate operations.
  78  * @ops: Hibernation operations to use in subsequent hibernation transitions.
  79  */
  80 void hibernation_set_ops(const struct platform_hibernation_ops *ops)
  81 {
  82         if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
  83             && ops->prepare && ops->finish && ops->enter && ops->pre_restore
  84             && ops->restore_cleanup && ops->leave)) {
  85                 WARN_ON(1);
  86                 return;
  87         }
  88         lock_system_sleep();
  89         hibernation_ops = ops;
  90         if (ops)
  91                 hibernation_mode = HIBERNATION_PLATFORM;
  92         else if (hibernation_mode == HIBERNATION_PLATFORM)
  93                 hibernation_mode = HIBERNATION_SHUTDOWN;
  94
  95         unlock_system_sleep();
  96 }
  97 EXPORT_SYMBOL_GPL(hibernation_set_ops);
  98
  99 static bool entering_platform_hibernation;
 100
 101 bool system_entering_hibernation(void)
 102 {
 103         return entering_platform_hibernation;
 104 }
 105 EXPORT_SYMBOL(system_entering_hibernation);
 106
 107 #ifdef CONFIG_PM_DEBUG
 108 static void hibernation_debug_sleep(void)
 109 {
 110         pr_info("hibernation debug: Waiting for 5 seconds.\n");
 111         mdelay(5000);
 112 }
 113
 114 static int hibernation_test(int level)
 115 {
 116         if (pm_test_level == level) {
 117                 hibernation_debug_sleep();
 118                 return 1;
 119         }
 120         return 0;
 121 }
 122 #else /* !CONFIG_PM_DEBUG */
 123 static int hibernation_test(int level) { return 0; }
 124 #endif /* !CONFIG_PM_DEBUG */
 125
 126 /**
 127  * platform_begin - Call platform to start hibernation.
 128  * @platform_mode: Whether or not to use the platform driver.
 129  */
 130 static int platform_begin(int platform_mode)
 131 {
 132         return (platform_mode && hibernation_ops) ?
 133                 hibernation_ops->begin() : 0;
 134 }
 135
 136 /**
 137  * platform_end - Call platform to finish transition to the working state.
 138  * @platform_mode: Whether or not to use the platform driver.
 139  */
 140 static void platform_end(int platform_mode)
 141 {
 142         if (platform_mode && hibernation_ops)
 143                 hibernation_ops->end();
 144 }
 145
 146 /**
 147  * platform_pre_snapshot - Call platform to prepare the machine for hibernation.
 148  * @platform_mode: Whether or not to use the platform driver.
 149  *
 150  * Use the platform driver to prepare the system for creating a hibernate image,
 151  * if so configured, and return an error code if that fails.
 152  */
 153
 154 static int platform_pre_snapshot(int platform_mode)
 155 {
 156         return (platform_mode && hibernation_ops) ?
 157                 hibernation_ops->pre_snapshot() : 0;
 158 }
 159
 160 /**
 161  * platform_leave - Call platform to prepare a transition to the working state.
 162  * @platform_mode: Whether or not to use the platform driver.
 163  *
 164  * Use the platform driver prepare to prepare the machine for switching to the
 165  * normal mode of operation.
 166  *
 167  * This routine is called on one CPU with interrupts disabled.
 168  */
 169 static void platform_leave(int platform_mode)
 170 {
 171         if (platform_mode && hibernation_ops)
 172                 hibernation_ops->leave();
 173 }
 174
 175 /**
 176  * platform_finish - Call platform to switch the system to the working state.
 177  * @platform_mode: Whether or not to use the platform driver.
 178  *
 179  * Use the platform driver to switch the machine to the normal mode of
 180  * operation.
 181  *
 182  * This routine must be called after platform_prepare().
 183  */
 184 static void platform_finish(int platform_mode)
 185 {
 186         if (platform_mode && hibernation_ops)
 187                 hibernation_ops->finish();
 188 }
 189
 190 /**
 191  * platform_pre_restore - Prepare for hibernate image restoration.
 192  * @platform_mode: Whether or not to use the platform driver.
 193  *
 194  * Use the platform driver to prepare the system for resume from a hibernation
 195  * image.
 196  *
 197  * If the restore fails after this function has been called,
 198  * platform_restore_cleanup() must be called.
 199  */
 200 static int platform_pre_restore(int platform_mode)
 201 {
 202         return (platform_mode && hibernation_ops) ?
 203                 hibernation_ops->pre_restore() : 0;
 204 }
 205
 206 /**
 207  * platform_restore_cleanup - Switch to the working state after failing restore.
 208  * @platform_mode: Whether or not to use the platform driver.
 209  *
 210  * Use the platform driver to switch the system to the normal mode of operation
 211  * after a failing restore.
 212  *
 213  * If platform_pre_restore() has been called before the failing restore, this
 214  * function must be called too, regardless of the result of
 215  * platform_pre_restore().
 216  */
 217 static void platform_restore_cleanup(int platform_mode)
 218 {
 219         if (platform_mode && hibernation_ops)
 220                 hibernation_ops->restore_cleanup();
 221 }
 222
 223 /**
 224  * platform_recover - Recover from a failure to suspend devices.
 225  * @platform_mode: Whether or not to use the platform driver.
 226  */
 227 static void platform_recover(int platform_mode)
 228 {
 229         if (platform_mode && hibernation_ops && hibernation_ops->recover)
 230                 hibernation_ops->recover();
 231 }
 232
 233 /**
 234  * swsusp_show_speed - Print time elapsed between two events during hibernation.
 235  * @start: Starting event.
 236  * @stop: Final event.
 237  * @nr_pages: Number of memory pages processed between @start and @stop.
 238  * @msg: Additional diagnostic message to print.
 239  */
 240 void swsusp_show_speed(ktime_t start, ktime_t stop,
 241                       unsigned nr_pages, char *msg)
 242 {
 243         ktime_t diff;
 244         u64 elapsed_centisecs64;
 245         unsigned int centisecs;
 246         unsigned int k;
 247         unsigned int kps;
 248
 249         diff = ktime_sub(stop, start);
 250         elapsed_centisecs64 = ktime_divns(diff, 10*NSEC_PER_MSEC);
 251         centisecs = elapsed_centisecs64;
 252         if (centisecs == 0)
 253                 centisecs = 1;  /* avoid div-by-zero */
 254         k = nr_pages * (PAGE_SIZE / 1024);
 255         kps = (k * 100) / centisecs;
 256         pr_info("%s %u kbytes in %u.%02u seconds (%u.%02u MB/s)\n",
 257                 msg, k, centisecs / 100, centisecs % 100, kps / 1000,
 258                 (kps % 1000) / 10);
 259 }
 260
 261 /**
 262  * create_image - Create a hibernation image.
 263  * @platform_mode: Whether or not to use the platform driver.
 264  *
 265  * Execute device drivers' "late" and "noirq" freeze callbacks, create a
 266  * hibernation image and run the drivers' "noirq" and "early" thaw callbacks.
 267  *
 268  * Control reappears in this routine after the subsequent restore.
 269  */
 270 static int create_image(int platform_mode)
 271 {
 272         int error;
 273
 274         error = dpm_suspend_end(PMSG_FREEZE);
 275         if (error) {
 276                 pr_err("Some devices failed to power down, aborting hibernation\n");
 277                 return error;
 278         }
 279
 280         error = platform_pre_snapshot(platform_mode);
 281         if (error || hibernation_test(TEST_PLATFORM))
 282                 goto Platform_finish;
 283
 284         error = suspend_disable_secondary_cpus();
 285         if (error || hibernation_test(TEST_CPUS))
 286                 goto Enable_cpus;
 287
 288         local_irq_disable();
 289
 290         system_state = SYSTEM_SUSPEND;
 291
 292         error = syscore_suspend();
 293         if (error) {
 294                 pr_err("Some system devices failed to power down, aborting hibernation\n");
 295                 goto Enable_irqs;
 296         }
 297
 298         if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
 299                 goto Power_up;
 300
 301         in_suspend = 1;
 302         save_processor_state();
 303         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);
 304         error = swsusp_arch_suspend();
 305         /* Restore control flow magically appears here */
 306         restore_processor_state();
 307         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
 308         if (error)
 309                 pr_err("Error %d creating hibernation image\n", error);
 310
 311         if (!in_suspend) {
 312                 events_check_enabled = false;
 313                 clear_free_pages();
 314         }
 315
 316         platform_leave(platform_mode);
 317
 318  Power_up:
 319         syscore_resume();
 320
 321  Enable_irqs:
 322         system_state = SYSTEM_RUNNING;
 323         local_irq_enable();
 324
 325  Enable_cpus:
 326         suspend_enable_secondary_cpus();
 327
 328  Platform_finish:
 329         platform_finish(platform_mode);
 330
 331         dpm_resume_start(in_suspend ?
 332                 (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
 333
 334         return error;
 335 }
 336
 337 /**
 338  * hibernation_snapshot - Quiesce devices and create a hibernation image.
 339  * @platform_mode: If set, use platform driver to prepare for the transition.
 340  *
 341  * This routine must be called with system_transition_mutex held.
 342  */
 343 int hibernation_snapshot(int platform_mode)
 344 {
 345         pm_message_t msg;
 346         int error;
 347
 348         pm_suspend_clear_flags();
 349         error = platform_begin(platform_mode);
 350         if (error)
 351                 goto Close;
 352
 353         /* Preallocate image memory before shutting down devices. */
 354         error = hibernate_preallocate_memory();
 355         if (error)
 356                 goto Close;
 357
 358         error = freeze_kernel_threads();
 359         if (error)
 360                 goto Cleanup;
 361
 362         if (hibernation_test(TEST_FREEZER)) {
 363
 364                 /*
 365                  * Indicate to the caller that we are returning due to a
 366                  * successful freezer test.
 367                  */
 368                 freezer_test_done = true;
 369                 goto Thaw;
 370         }
 371
 372         error = dpm_prepare(PMSG_FREEZE);
 373         if (error) {
 374                 dpm_complete(PMSG_RECOVER);
 375                 goto Thaw;
 376         }
 377
 378         suspend_console();
 379         pm_restrict_gfp_mask();
 380
 381         error = dpm_suspend(PMSG_FREEZE);
 382
 383         if (error || hibernation_test(TEST_DEVICES))
 384                 platform_recover(platform_mode);
 385         else
 386                 error = create_image(platform_mode);
 387
 388         /*
 389          * In the case that we call create_image() above, the control
 390          * returns here (1) after the image has been created or the
 391          * image creation has failed and (2) after a successful restore.
 392          */
 393
 394         /* We may need to release the preallocated image pages here. */
 395         if (error || !in_suspend)
 396                 swsusp_free();
 397
 398         msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
 399         dpm_resume(msg);
 400
 401         if (error || !in_suspend)
 402                 pm_restore_gfp_mask();
 403
 404         resume_console();
 405         dpm_complete(msg);
 406
 407  Close:
 408         platform_end(platform_mode);
 409         return error;
 410
 411  Thaw:
 412         thaw_kernel_threads();
 413  Cleanup:
 414         swsusp_free();
 415         goto Close;
 416 }
 417
 418 int __weak hibernate_resume_nonboot_cpu_disable(void)
 419 {
 420         return suspend_disable_secondary_cpus();
 421 }
 422
 423 /**
 424  * resume_target_kernel - Restore system state from a hibernation image.
 425  * @platform_mode: Whether or not to use the platform driver.
 426  *
 427  * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
 428  * contents of highmem that have not been restored yet from the image and run
 429  * the low-level code that will restore the remaining contents of memory and
 430  * switch to the just restored target kernel.
 431  */
 432 static int resume_target_kernel(bool platform_mode)
 433 {
 434         int error;
 435
 436         error = dpm_suspend_end(PMSG_QUIESCE);
 437         if (error) {
 438                 pr_err("Some devices failed to power down, aborting resume\n");
 439                 return error;
 440         }
 441
 442         error = platform_pre_restore(platform_mode);
 443         if (error)
 444                 goto Cleanup;
 445
 446         error = hibernate_resume_nonboot_cpu_disable();
 447         if (error)
 448                 goto Enable_cpus;
 449
 450         local_irq_disable();
 451         system_state = SYSTEM_SUSPEND;
 452
 453         error = syscore_suspend();
 454         if (error)
 455                 goto Enable_irqs;
 456
 457         save_processor_state();
 458         error = restore_highmem();
 459         if (!error) {
 460                 error = swsusp_arch_resume();
 461                 /*
 462                  * The code below is only ever reached in case of a failure.
 463                  * Otherwise, execution continues at the place where
 464                  * swsusp_arch_suspend() was called.
 465                  */
 466                 BUG_ON(!error);
 467                 /*
 468                  * This call to restore_highmem() reverts the changes made by
 469                  * the previous one.
 470                  */
 471                 restore_highmem();
 472         }
 473         /*
 474          * The only reason why swsusp_arch_resume() can fail is memory being
 475          * very tight, so we have to free it as soon as we can to avoid
 476          * subsequent failures.
 477          */
 478         swsusp_free();
 479         restore_processor_state();
 480         touch_softlockup_watchdog();
 481
 482         syscore_resume();
 483
 484  Enable_irqs:
 485         system_state = SYSTEM_RUNNING;
 486         local_irq_enable();
 487
 488  Enable_cpus:
 489         suspend_enable_secondary_cpus();
 490
 491  Cleanup:
 492         platform_restore_cleanup(platform_mode);
 493
 494         dpm_resume_start(PMSG_RECOVER);
 495
 496         return error;
 497 }
 498
 499 /**
 500  * hibernation_restore - Quiesce devices and restore from a hibernation image.
 501  * @platform_mode: If set, use platform driver to prepare for the transition.
 502  *
 503  * This routine must be called with system_transition_mutex held.  If it is
 504  * successful, control reappears in the restored target kernel in
 505  * hibernation_snapshot().
 506  */
 507 int hibernation_restore(int platform_mode)
 508 {
 509         int error;
 510
 511         pm_prepare_console();
 512         suspend_console();
 513         pm_restrict_gfp_mask();
 514         error = dpm_suspend_start(PMSG_QUIESCE);
 515         if (!error) {
 516                 error = resume_target_kernel(platform_mode);
 517                 /*
 518                  * The above should either succeed and jump to the new kernel,
 519                  * or return with an error. Otherwise things are just
 520                  * undefined, so let's be paranoid.
 521                  */
 522                 BUG_ON(!error);
 523         }
 524         dpm_resume_end(PMSG_RECOVER);
 525         pm_restore_gfp_mask();
 526         resume_console();
 527         pm_restore_console();
 528         return error;
 529 }
 530
 531 /**
 532  * hibernation_platform_enter - Power off the system using the platform driver.
 533  */
 534 int hibernation_platform_enter(void)
 535 {
 536         int error;
 537
 538         if (!hibernation_ops)
 539                 return -ENOSYS;
 540
 541         /*
 542          * We have cancelled the power transition by running
 543          * hibernation_ops->finish() before saving the image, so we should let
 544          * the firmware know that we're going to enter the sleep state after all
 545          */
 546         error = hibernation_ops->begin();
 547         if (error)
 548                 goto Close;
 549
 550         entering_platform_hibernation = true;
 551         suspend_console();
 552         error = dpm_suspend_start(PMSG_HIBERNATE);
 553         if (error) {
 554                 if (hibernation_ops->recover)
 555                         hibernation_ops->recover();
 556                 goto Resume_devices;
 557         }
 558
 559         error = dpm_suspend_end(PMSG_HIBERNATE);
 560         if (error)
 561                 goto Resume_devices;
 562
 563         error = hibernation_ops->prepare();
 564         if (error)
 565                 goto Platform_finish;
 566
 567         error = suspend_disable_secondary_cpus();
 568         if (error)
 569                 goto Enable_cpus;
 570
 571         local_irq_disable();
 572         system_state = SYSTEM_SUSPEND;
 573         syscore_suspend();
 574         if (pm_wakeup_pending()) {
 575                 error = -EAGAIN;
 576                 goto Power_up;
 577         }
 578
 579         hibernation_ops->enter();
 580         /* We should never get here */
 581         while (1);
 582
 583  Power_up:
 584         syscore_resume();
 585         system_state = SYSTEM_RUNNING;
 586         local_irq_enable();
 587
 588  Enable_cpus:
 589         suspend_enable_secondary_cpus();
 590
 591  Platform_finish:
 592         hibernation_ops->finish();
 593
 594         dpm_resume_start(PMSG_RESTORE);
 595
 596  Resume_devices:
 597         entering_platform_hibernation = false;
 598         dpm_resume_end(PMSG_RESTORE);
 599         resume_console();
 600
 601  Close:
 602         hibernation_ops->end();
 603
 604         return error;
 605 }
 606
 607 /**
 608  * power_down - Shut the machine down for hibernation.
 609  *
 610  * Use the platform driver, if configured, to put the system into the sleep
 611  * state corresponding to hibernation, or try to power it off or reboot,
 612  * depending on the value of hibernation_mode.
 613  */
 614 static void power_down(void)
 615 {
 616 #ifdef CONFIG_SUSPEND
 617         int error;
 618
 619         if (hibernation_mode == HIBERNATION_SUSPEND) {
 620                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 621                 if (error) {
 622                         hibernation_mode = hibernation_ops ?
 623                                                 HIBERNATION_PLATFORM :
 624                                                 HIBERNATION_SHUTDOWN;
 625                 } else {
 626                         /* Restore swap signature. */
 627                         error = swsusp_unmark();
 628                         if (error)
 629                                 pr_err("Swap will be unusable! Try swapon -a.\n");
 630
 631                         return;
 632                 }
 633         }
 634 #endif
 635
 636         switch (hibernation_mode) {
 637         case HIBERNATION_REBOOT:
 638                 kernel_restart(NULL);
 639                 break;
 640         case HIBERNATION_PLATFORM:
 641                 hibernation_platform_enter();
 642                 /* Fall through */
 643         case HIBERNATION_SHUTDOWN:
 644                 if (pm_power_off)
 645                         kernel_power_off();
 646                 break;
 647         }
 648         kernel_halt();
 649         /*
 650          * Valid image is on the disk, if we continue we risk serious data
 651          * corruption after resume.
 652          */
 653         pr_crit("Power down manually\n");
 654         while (1)
 655                 cpu_relax();
 656 }
 657
 658 static int load_image_and_restore(void)
 659 {
 660         int error;
 661         unsigned int flags;
 662
 663         pm_pr_dbg("Loading hibernation image.\n");
 664
 665         lock_device_hotplug();
 666         error = create_basic_memory_bitmaps();
 667         if (error)
 668                 goto Unlock;
 669
 670         error = swsusp_read(&flags);
 671         swsusp_close(FMODE_READ);
 672         if (!error)
 673                 hibernation_restore(flags & SF_PLATFORM_MODE);
 674
 675         pr_err("Failed to load hibernation image, recovering.\n");
 676         swsusp_free();
 677         free_basic_memory_bitmaps();
 678  Unlock:
 679         unlock_device_hotplug();
 680
 681         return error;
 682 }
 683
 684 /**
 685  * hibernate - Carry out system hibernation, including saving the image.
 686  */
 687 int hibernate(void)
 688 {
 689         int error, nr_calls = 0;
 690         bool snapshot_test = false;
 691
 692         if (!hibernation_available()) {
 693                 pm_pr_dbg("Hibernation not available.\n");
 694                 return -EPERM;
 695         }
 696
 697         lock_system_sleep();
 698         /* The snapshot device should not be opened while we're running */
 699         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 700                 error = -EBUSY;
 701                 goto Unlock;
 702         }
 703
 704         pr_info("hibernation entry\n");
 705         pm_prepare_console();
 706         error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls);
 707         if (error) {
 708                 nr_calls--;
 709                 goto Exit;
 710         }
 711
 712         pr_info("Syncing filesystems ... \n");
 713         ksys_sync();
 714         pr_info("done.\n");
 715
 716         error = freeze_processes();
 717         if (error)
 718                 goto Exit;
 719
 720         lock_device_hotplug();
 721         /* Allocate memory management structures */
 722         error = create_basic_memory_bitmaps();
 723         if (error)
 724                 goto Thaw;
 725
 726         error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
 727         if (error || freezer_test_done)
 728                 goto Free_bitmaps;
 729
 730         if (in_suspend) {
 731                 unsigned int flags = 0;
 732
 733                 if (hibernation_mode == HIBERNATION_PLATFORM)
 734                         flags |= SF_PLATFORM_MODE;
 735                 if (nocompress)
 736                         flags |= SF_NOCOMPRESS_MODE;
 737                 else
 738                         flags |= SF_CRC32_MODE;
 739
 740                 pm_pr_dbg("Writing image.\n");
 741                 error = swsusp_write(flags);
 742                 swsusp_free();
 743                 if (!error) {
 744                         if (hibernation_mode == HIBERNATION_TEST_RESUME)
 745                                 snapshot_test = true;
 746                         else
 747                                 power_down();
 748                 }
 749                 in_suspend = 0;
 750                 pm_restore_gfp_mask();
 751         } else {
 752                 pm_pr_dbg("Image restored successfully.\n");
 753         }
 754
 755  Free_bitmaps:
 756         free_basic_memory_bitmaps();
 757  Thaw:
 758         unlock_device_hotplug();
 759         if (snapshot_test) {
 760                 pm_pr_dbg("Checking hibernation image\n");
 761                 error = swsusp_check();
 762                 if (!error)
 763                         error = load_image_and_restore();
 764         }
 765         thaw_processes();
 766
 767         /* Don't bother checking whether freezer_test_done is true */
 768         freezer_test_done = false;
 769  Exit:
 770         __pm_notifier_call_chain(PM_POST_HIBERNATION, nr_calls, NULL);
 771         pm_restore_console();
 772         atomic_inc(&snapshot_device_available);
 773  Unlock:
 774         unlock_system_sleep();
 775         pr_info("hibernation exit\n");
 776
 777         return error;
 778 }
 779
 780
 781 /**
 782  * software_resume - Resume from a saved hibernation image.
 783  *
 784  * This routine is called as a late initcall, when all devices have been
 785  * discovered and initialized already.
 786  *
 787  * The image reading code is called to see if there is a hibernation image
 788  * available for reading.  If that is the case, devices are quiesced and the
 789  * contents of memory is restored from the saved image.
 790  *
 791  * If this is successful, control reappears in the restored target kernel in
 792  * hibernation_snapshot() which returns to hibernate().  Otherwise, the routine
 793  * attempts to recover gracefully and make the kernel return to the normal mode
 794  * of operation.
 795  */
 796 static int software_resume(void)
 797 {
 798         int error, nr_calls = 0;
 799
 800         /*
 801          * If the user said "noresume".. bail out early.
 802          */
 803         if (noresume || !hibernation_available())
 804                 return 0;
 805
 806         /*
 807          * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
 808          * is configured into the kernel. Since the regular hibernate
 809          * trigger path is via sysfs which takes a buffer mutex before
 810          * calling hibernate functions (which take system_transition_mutex)
 811          * this can cause lockdep to complain about a possible ABBA deadlock
 812          * which cannot happen since we're in the boot code here and
 813          * sysfs can't be invoked yet. Therefore, we use a subclass
 814          * here to avoid lockdep complaining.
 815          */
 816         mutex_lock_nested(&system_transition_mutex, SINGLE_DEPTH_NESTING);
 817
 818         if (swsusp_resume_device)
 819                 goto Check_image;
 820
 821         if (!strlen(resume_file)) {
 822                 error = -ENOENT;
 823                 goto Unlock;
 824         }
 825
 826         pm_pr_dbg("Checking hibernation image partition %s\n", resume_file);
 827
 828         if (resume_delay) {
 829                 pr_info("Waiting %dsec before reading resume device ...\n",
 830                         resume_delay);
 831                 ssleep(resume_delay);
 832         }
 833
 834         /* Check if the device is there */
 835         swsusp_resume_device = name_to_dev_t(resume_file);
 836
 837         /*
 838          * name_to_dev_t is ineffective to verify parition if resume_file is in
 839          * integer format. (e.g. major:minor)
 840          */
 841         if (isdigit(resume_file[0]) && resume_wait) {
 842                 int partno;
 843                 while (!get_gendisk(swsusp_resume_device, &partno))
 844                         msleep(10);
 845         }
 846
 847         if (!swsusp_resume_device) {
 848                 /*
 849                  * Some device discovery might still be in progress; we need
 850                  * to wait for this to finish.
 851                  */
 852                 wait_for_device_probe();
 853
 854                 if (resume_wait) {
 855                         while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
 856                                 msleep(10);
 857                         async_synchronize_full();
 858                 }
 859
 860                 swsusp_resume_device = name_to_dev_t(resume_file);
 861                 if (!swsusp_resume_device) {
 862                         error = -ENODEV;
 863                         goto Unlock;
 864                 }
 865         }
 866
 867  Check_image:
 868         pm_pr_dbg("Hibernation image partition %d:%d present\n",
 869                 MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 870
 871         pm_pr_dbg("Looking for hibernation image.\n");
 872         error = swsusp_check();
 873         if (error)
 874                 goto Unlock;
 875
 876         /* The snapshot device should not be opened while we're running */
 877         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 878                 error = -EBUSY;
 879                 swsusp_close(FMODE_READ);
 880                 goto Unlock;
 881         }
 882
 883         pr_info("resume from hibernation\n");
 884         pm_prepare_console();
 885         error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls);
 886         if (error) {
 887                 nr_calls--;
 888                 goto Close_Finish;
 889         }
 890
 891         pm_pr_dbg("Preparing processes for restore.\n");
 892         error = freeze_processes();
 893         if (error)
 894                 goto Close_Finish;
 895         error = load_image_and_restore();
 896         thaw_processes();
 897  Finish:
 898         __pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);
 899         pm_restore_console();
 900         pr_info("resume from hibernation failed (%d)\n", error);
 901         atomic_inc(&snapshot_device_available);
 902         /* For success case, the suspend path will release the lock */
 903  Unlock:
 904         mutex_unlock(&system_transition_mutex);
 905         pm_pr_dbg("Hibernation image not present or could not be loaded.\n");
 906         return error;
 907  Close_Finish:
 908         swsusp_close(FMODE_READ);
 909         goto Finish;
 910 }
 911
 912 late_initcall_sync(software_resume);
 913
 914
 915 static const char * const hibernation_modes[] = {
 916         [HIBERNATION_PLATFORM]  = "platform",
 917         [HIBERNATION_SHUTDOWN]  = "shutdown",
 918         [HIBERNATION_REBOOT]    = "reboot",
 919 #ifdef CONFIG_SUSPEND
 920         [HIBERNATION_SUSPEND]   = "suspend",
 921 #endif
 922         [HIBERNATION_TEST_RESUME]       = "test_resume",
 923 };
 924
 925 /*
 926  * /sys/power/disk - Control hibernation mode.
 927  *
 928  * Hibernation can be handled in several ways.  There are a few different ways
 929  * to put the system into the sleep state: using the platform driver (e.g. ACPI
 930  * or other hibernation_ops), powering it off or rebooting it (for testing
 931  * mostly).
 932  *
 933  * The sysfs file /sys/power/disk provides an interface for selecting the
 934  * hibernation mode to use.  Reading from this file causes the available modes
 935  * to be printed.  There are 3 modes that can be supported:
 936  *
 937  *      'platform'
 938  *      'shutdown'
 939  *      'reboot'
 940  *
 941  * If a platform hibernation driver is in use, 'platform' will be supported
 942  * and will be used by default.  Otherwise, 'shutdown' will be used by default.
 943  * The selected option (i.e. the one corresponding to the current value of
 944  * hibernation_mode) is enclosed by a square bracket.
 945  *
 946  * To select a given hibernation mode it is necessary to write the mode's
 947  * string representation (as returned by reading from /sys/power/disk) back
 948  * into /sys/power/disk.
 949  */
 950
 951 static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
 952                          char *buf)
 953 {
 954         int i;
 955         char *start = buf;
 956
 957         if (!hibernation_available())
 958                 return sprintf(buf, "[disabled]\n");
 959
 960         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 961                 if (!hibernation_modes[i])
 962                         continue;
 963                 switch (i) {
 964                 case HIBERNATION_SHUTDOWN:
 965                 case HIBERNATION_REBOOT:
 966 #ifdef CONFIG_SUSPEND
 967                 case HIBERNATION_SUSPEND:
 968 #endif
 969                 case HIBERNATION_TEST_RESUME:
 970                         break;
 971                 case HIBERNATION_PLATFORM:
 972                         if (hibernation_ops)
 973                                 break;
 974                         /* not a valid mode, continue with loop */
 975                         continue;
 976                 }
 977                 if (i == hibernation_mode)
 978                         buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
 979                 else
 980                         buf += sprintf(buf, "%s ", hibernation_modes[i]);
 981         }
 982         buf += sprintf(buf, "\n");
 983         return buf-start;
 984 }
 985
 986 static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
 987                           const char *buf, size_t n)
 988 {
 989         int error = 0;
 990         int i;
 991         int len;
 992         char *p;
 993         int mode = HIBERNATION_INVALID;
 994
 995         if (!hibernation_available())
 996                 return -EPERM;
 997
 998         p = memchr(buf, '\n', n);
 999         len = p ? p - buf : n;
1000
1001         lock_system_sleep();
1002         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
1003                 if (len == strlen(hibernation_modes[i])
1004                     && !strncmp(buf, hibernation_modes[i], len)) {
1005                         mode = i;
1006                         break;
1007                 }
1008         }
1009         if (mode != HIBERNATION_INVALID) {
1010                 switch (mode) {
1011                 case HIBERNATION_SHUTDOWN:
1012                 case HIBERNATION_REBOOT:
1013 #ifdef CONFIG_SUSPEND
1014                 case HIBERNATION_SUSPEND:
1015 #endif
1016                 case HIBERNATION_TEST_RESUME:
1017                         hibernation_mode = mode;
1018                         break;
1019                 case HIBERNATION_PLATFORM:
1020                         if (hibernation_ops)
1021                                 hibernation_mode = mode;
1022                         else
1023                                 error = -EINVAL;
1024                 }
1025         } else
1026                 error = -EINVAL;
1027
1028         if (!error)
1029                 pm_pr_dbg("Hibernation mode set to '%s'\n",
1030                                hibernation_modes[mode]);
1031         unlock_system_sleep();
1032         return error ? error : n;
1033 }
1034
1035 power_attr(disk);
1036
1037 static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
1038                            char *buf)
1039 {
1040         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
1041                        MINOR(swsusp_resume_device));
1042 }
1043
1044 static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
1045                             const char *buf, size_t n)
1046 {
1047         dev_t res;
1048         int len = n;
1049         char *name;
1050
1051         if (len && buf[len-1] == '\n')
1052                 len--;
1053         name = kstrndup(buf, len, GFP_KERNEL);
1054         if (!name)
1055                 return -ENOMEM;
1056
1057         res = name_to_dev_t(name);
1058         kfree(name);
1059         if (!res)
1060                 return -EINVAL;
1061
1062         lock_system_sleep();
1063         swsusp_resume_device = res;
1064         unlock_system_sleep();
1065         pm_pr_dbg("Configured resume from disk to %u\n", swsusp_resume_device);
1066         noresume = 0;
1067         software_resume();
1068         return n;
1069 }
1070
1071 power_attr(resume);
1072
1073 static ssize_t resume_offset_show(struct kobject *kobj,
1074                                   struct kobj_attribute *attr, char *buf)
1075 {
1076         return sprintf(buf, "%llu\n", (unsigned long long)swsusp_resume_block);
1077 }
1078
1079 static ssize_t resume_offset_store(struct kobject *kobj,
1080                                    struct kobj_attribute *attr, const char *buf,
1081                                    size_t n)
1082 {
1083         unsigned long long offset;
1084         int rc;
1085
1086         rc = kstrtoull(buf, 0, &offset);
1087         if (rc)
1088                 return rc;
1089         swsusp_resume_block = offset;
1090
1091         return n;
1092 }
1093
1094 power_attr(resume_offset);
1095
1096 static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
1097                                char *buf)
1098 {
1099         return sprintf(buf, "%lu\n", image_size);
1100 }
1101
1102 static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
1103                                 const char *buf, size_t n)
1104 {
1105         unsigned long size;
1106
1107         if (sscanf(buf, "%lu", &size) == 1) {
1108                 image_size = size;
1109                 return n;
1110         }
1111
1112         return -EINVAL;
1113 }
1114
1115 power_attr(image_size);
1116
1117 static ssize_t reserved_size_show(struct kobject *kobj,
1118                                   struct kobj_attribute *attr, char *buf)
1119 {
1120         return sprintf(buf, "%lu\n", reserved_size);
1121 }
1122
1123 static ssize_t reserved_size_store(struct kobject *kobj,
1124                                    struct kobj_attribute *attr,
1125                                    const char *buf, size_t n)
1126 {
1127         unsigned long size;
1128
1129         if (sscanf(buf, "%lu", &size) == 1) {
1130                 reserved_size = size;
1131                 return n;
1132         }
1133
1134         return -EINVAL;
1135 }
1136
1137 power_attr(reserved_size);
1138
1139 static struct attribute * g[] = {
1140         &disk_attr.attr,
1141         &resume_offset_attr.attr,
1142         &resume_attr.attr,
1143         &image_size_attr.attr,
1144         &reserved_size_attr.attr,
1145         NULL,
1146 };
1147
1148
1149 static const struct attribute_group attr_group = {
1150         .attrs = g,
1151 };
1152
1153
1154 static int __init pm_disk_init(void)
1155 {
1156         return sysfs_create_group(power_kobj, &attr_group);
1157 }
1158
1159 core_initcall(pm_disk_init);
1160
1161
1162 static int __init resume_setup(char *str)
1163 {
1164         if (noresume)
1165                 return 1;
1166
1167         strncpy( resume_file, str, 255 );
1168         return 1;
1169 }
1170
1171 static int __init resume_offset_setup(char *str)
1172 {
1173         unsigned long long offset;
1174
1175         if (noresume)
1176                 return 1;
1177
1178         if (sscanf(str, "%llu", &offset) == 1)
1179                 swsusp_resume_block = offset;
1180
1181         return 1;
1182 }
1183
1184 static int __init hibernate_setup(char *str)
1185 {
1186         if (!strncmp(str, "noresume", 8)) {
1187                 noresume = 1;
1188         } else if (!strncmp(str, "nocompress", 10)) {
1189                 nocompress = 1;
1190         } else if (!strncmp(str, "no", 2)) {
1191                 noresume = 1;
1192                 nohibernate = 1;
1193         } else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)
1194                    && !strncmp(str, "protect_image", 13)) {
1195                 enable_restore_image_protection();
1196         }
1197         return 1;
1198 }
1199
1200 static int __init noresume_setup(char *str)
1201 {
1202         noresume = 1;
1203         return 1;
1204 }
1205
1206 static int __init resumewait_setup(char *str)
1207 {
1208         resume_wait = 1;
1209         return 1;
1210 }
1211
1212 static int __init resumedelay_setup(char *str)
1213 {
1214         int rc = kstrtouint(str, 0, &resume_delay);
1215
1216         if (rc)
1217                 return rc;
1218         return 1;
1219 }
1220
1221 static int __init nohibernate_setup(char *str)
1222 {
1223         noresume = 1;
1224         nohibernate = 1;
1225         return 1;
1226 }
1227
1228 __setup("noresume", noresume_setup);
1229 __setup("resume_offset=", resume_offset_setup);
1230 __setup("resume=", resume_setup);
1231 __setup("hibernate=", hibernate_setup);
1232 __setup("resumewait", resumewait_setup);
1233 __setup("resumedelay=", resumedelay_setup);
1234 __setup("nohibernate", nohibernate_setup);