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 #include <linux/export.h>
  14 #include <linux/suspend.h>
  15 #include <linux/syscalls.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/console.h>
  25 #include <linux/cpu.h>
  26 #include <linux/freezer.h>
  27 #include <linux/gfp.h>
  28 #include <linux/syscore_ops.h>
  29 #include <linux/ctype.h>
  30 #include <linux/genhd.h>
  31 #include <linux/ktime.h>
  32 #include <trace/events/power.h>
  33
  34 #include "power.h"
  35
  36
  37 static int nocompress;
  38 static int noresume;
  39 static int nohibernate;
  40 static int resume_wait;
  41 static unsigned int resume_delay;
  42 static char resume_file[256] = CONFIG_PM_STD_PARTITION;
  43 dev_t swsusp_resume_device;
  44 sector_t swsusp_resume_block;
  45 __visible int in_suspend __nosavedata;
  46
  47 enum {
  48         HIBERNATION_INVALID,
  49         HIBERNATION_PLATFORM,
  50         HIBERNATION_SHUTDOWN,
  51         HIBERNATION_REBOOT,
  52 #ifdef CONFIG_SUSPEND
  53         HIBERNATION_SUSPEND,
  54 #endif
  55         /* keep last */
  56         __HIBERNATION_AFTER_LAST
  57 };
  58 #define HIBERNATION_MAX (__HIBERNATION_AFTER_LAST-1)
  59 #define HIBERNATION_FIRST (HIBERNATION_INVALID + 1)
  60
  61 static int hibernation_mode = HIBERNATION_SHUTDOWN;
  62
  63 bool freezer_test_done;
  64
  65 static const struct platform_hibernation_ops *hibernation_ops;
  66
  67 bool hibernation_available(void)
  68 {
  69         return (nohibernate == 0);
  70 }
  71
  72 /**
  73  * hibernation_set_ops - Set the global hibernate operations.
  74  * @ops: Hibernation operations to use in subsequent hibernation transitions.
  75  */
  76 void hibernation_set_ops(const struct platform_hibernation_ops *ops)
  77 {
  78         if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
  79             && ops->prepare && ops->finish && ops->enter && ops->pre_restore
  80             && ops->restore_cleanup && ops->leave)) {
  81                 WARN_ON(1);
  82                 return;
  83         }
  84         lock_system_sleep();
  85         hibernation_ops = ops;
  86         if (ops)
  87                 hibernation_mode = HIBERNATION_PLATFORM;
  88         else if (hibernation_mode == HIBERNATION_PLATFORM)
  89                 hibernation_mode = HIBERNATION_SHUTDOWN;
  90
  91         unlock_system_sleep();
  92 }
  93 EXPORT_SYMBOL_GPL(hibernation_set_ops);
  94
  95 static bool entering_platform_hibernation;
  96
  97 bool system_entering_hibernation(void)
  98 {
  99         return entering_platform_hibernation;
 100 }
 101 EXPORT_SYMBOL(system_entering_hibernation);
 102
 103 #ifdef CONFIG_PM_DEBUG
 104 static void hibernation_debug_sleep(void)
 105 {
 106         printk(KERN_INFO "hibernation debug: Waiting for 5 seconds.\n");
 107         mdelay(5000);
 108 }
 109
 110 static int hibernation_test(int level)
 111 {
 112         if (pm_test_level == level) {
 113                 hibernation_debug_sleep();
 114                 return 1;
 115         }
 116         return 0;
 117 }
 118 #else /* !CONFIG_PM_DEBUG */
 119 static int hibernation_test(int level) { return 0; }
 120 #endif /* !CONFIG_PM_DEBUG */
 121
 122 /**
 123  * platform_begin - Call platform to start hibernation.
 124  * @platform_mode: Whether or not to use the platform driver.
 125  */
 126 static int platform_begin(int platform_mode)
 127 {
 128         return (platform_mode && hibernation_ops) ?
 129                 hibernation_ops->begin() : 0;
 130 }
 131
 132 /**
 133  * platform_end - Call platform to finish transition to the working state.
 134  * @platform_mode: Whether or not to use the platform driver.
 135  */
 136 static void platform_end(int platform_mode)
 137 {
 138         if (platform_mode && hibernation_ops)
 139                 hibernation_ops->end();
 140 }
 141
 142 /**
 143  * platform_pre_snapshot - Call platform to prepare the machine for hibernation.
 144  * @platform_mode: Whether or not to use the platform driver.
 145  *
 146  * Use the platform driver to prepare the system for creating a hibernate image,
 147  * if so configured, and return an error code if that fails.
 148  */
 149
 150 static int platform_pre_snapshot(int platform_mode)
 151 {
 152         return (platform_mode && hibernation_ops) ?
 153                 hibernation_ops->pre_snapshot() : 0;
 154 }
 155
 156 /**
 157  * platform_leave - Call platform to prepare a transition to the working state.
 158  * @platform_mode: Whether or not to use the platform driver.
 159  *
 160  * Use the platform driver prepare to prepare the machine for switching to the
 161  * normal mode of operation.
 162  *
 163  * This routine is called on one CPU with interrupts disabled.
 164  */
 165 static void platform_leave(int platform_mode)
 166 {
 167         if (platform_mode && hibernation_ops)
 168                 hibernation_ops->leave();
 169 }
 170
 171 /**
 172  * platform_finish - Call platform to switch the system to the working state.
 173  * @platform_mode: Whether or not to use the platform driver.
 174  *
 175  * Use the platform driver to switch the machine to the normal mode of
 176  * operation.
 177  *
 178  * This routine must be called after platform_prepare().
 179  */
 180 static void platform_finish(int platform_mode)
 181 {
 182         if (platform_mode && hibernation_ops)
 183                 hibernation_ops->finish();
 184 }
 185
 186 /**
 187  * platform_pre_restore - Prepare for hibernate image restoration.
 188  * @platform_mode: Whether or not to use the platform driver.
 189  *
 190  * Use the platform driver to prepare the system for resume from a hibernation
 191  * image.
 192  *
 193  * If the restore fails after this function has been called,
 194  * platform_restore_cleanup() must be called.
 195  */
 196 static int platform_pre_restore(int platform_mode)
 197 {
 198         return (platform_mode && hibernation_ops) ?
 199                 hibernation_ops->pre_restore() : 0;
 200 }
 201
 202 /**
 203  * platform_restore_cleanup - Switch to the working state after failing restore.
 204  * @platform_mode: Whether or not to use the platform driver.
 205  *
 206  * Use the platform driver to switch the system to the normal mode of operation
 207  * after a failing restore.
 208  *
 209  * If platform_pre_restore() has been called before the failing restore, this
 210  * function must be called too, regardless of the result of
 211  * platform_pre_restore().
 212  */
 213 static void platform_restore_cleanup(int platform_mode)
 214 {
 215         if (platform_mode && hibernation_ops)
 216                 hibernation_ops->restore_cleanup();
 217 }
 218
 219 /**
 220  * platform_recover - Recover from a failure to suspend devices.
 221  * @platform_mode: Whether or not to use the platform driver.
 222  */
 223 static void platform_recover(int platform_mode)
 224 {
 225         if (platform_mode && hibernation_ops && hibernation_ops->recover)
 226                 hibernation_ops->recover();
 227 }
 228
 229 /**
 230  * swsusp_show_speed - Print time elapsed between two events during hibernation.
 231  * @start: Starting event.
 232  * @stop: Final event.
 233  * @nr_pages: Number of memory pages processed between @start and @stop.
 234  * @msg: Additional diagnostic message to print.
 235  */
 236 void swsusp_show_speed(ktime_t start, ktime_t stop,
 237                       unsigned nr_pages, char *msg)
 238 {
 239         ktime_t diff;
 240         u64 elapsed_centisecs64;
 241         unsigned int centisecs;
 242         unsigned int k;
 243         unsigned int kps;
 244
 245         diff = ktime_sub(stop, start);
 246         elapsed_centisecs64 = ktime_divns(diff, 10*NSEC_PER_MSEC);
 247         centisecs = elapsed_centisecs64;
 248         if (centisecs == 0)
 249                 centisecs = 1;  /* avoid div-by-zero */
 250         k = nr_pages * (PAGE_SIZE / 1024);
 251         kps = (k * 100) / centisecs;
 252         printk(KERN_INFO "PM: %s %u kbytes in %u.%02u seconds (%u.%02u MB/s)\n",
 253                         msg, k,
 254                         centisecs / 100, centisecs % 100,
 255                         kps / 1000, (kps % 1000) / 10);
 256 }
 257
 258 /**
 259  * create_image - Create a hibernation image.
 260  * @platform_mode: Whether or not to use the platform driver.
 261  *
 262  * Execute device drivers' "late" and "noirq" freeze callbacks, create a
 263  * hibernation image and run the drivers' "noirq" and "early" thaw callbacks.
 264  *
 265  * Control reappears in this routine after the subsequent restore.
 266  */
 267 static int create_image(int platform_mode)
 268 {
 269         int error;
 270
 271         error = dpm_suspend_end(PMSG_FREEZE);
 272         if (error) {
 273                 printk(KERN_ERR "PM: Some devices failed to power down, "
 274                         "aborting hibernation\n");
 275                 return error;
 276         }
 277
 278         error = platform_pre_snapshot(platform_mode);
 279         if (error || hibernation_test(TEST_PLATFORM))
 280                 goto Platform_finish;
 281
 282         error = disable_nonboot_cpus();
 283         if (error || hibernation_test(TEST_CPUS))
 284                 goto Enable_cpus;
 285
 286         local_irq_disable();
 287
 288         error = syscore_suspend();
 289         if (error) {
 290                 printk(KERN_ERR "PM: Some system devices failed to power down, "
 291                         "aborting hibernation\n");
 292                 goto Enable_irqs;
 293         }
 294
 295         if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
 296                 goto Power_up;
 297
 298         in_suspend = 1;
 299         save_processor_state();
 300         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);
 301         error = swsusp_arch_suspend();
 302         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
 303         if (error)
 304                 printk(KERN_ERR "PM: Error %d creating hibernation image\n",
 305                         error);
 306         /* Restore control flow magically appears here */
 307         restore_processor_state();
 308         if (!in_suspend)
 309                 events_check_enabled = false;
 310
 311         platform_leave(platform_mode);
 312
 313  Power_up:
 314         syscore_resume();
 315
 316  Enable_irqs:
 317         local_irq_enable();
 318
 319  Enable_cpus:
 320         enable_nonboot_cpus();
 321
 322  Platform_finish:
 323         platform_finish(platform_mode);
 324
 325         dpm_resume_start(in_suspend ?
 326                 (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
 327
 328         return error;
 329 }
 330
 331 /**
 332  * hibernation_snapshot - Quiesce devices and create a hibernation image.
 333  * @platform_mode: If set, use platform driver to prepare for the transition.
 334  *
 335  * This routine must be called with pm_mutex held.
 336  */
 337 int hibernation_snapshot(int platform_mode)
 338 {
 339         pm_message_t msg;
 340         int error;
 341
 342         error = platform_begin(platform_mode);
 343         if (error)
 344                 goto Close;
 345
 346         /* Preallocate image memory before shutting down devices. */
 347         error = hibernate_preallocate_memory();
 348         if (error)
 349                 goto Close;
 350
 351         error = freeze_kernel_threads();
 352         if (error)
 353                 goto Cleanup;
 354
 355         if (hibernation_test(TEST_FREEZER)) {
 356
 357                 /*
 358                  * Indicate to the caller that we are returning due to a
 359                  * successful freezer test.
 360                  */
 361                 freezer_test_done = true;
 362                 goto Thaw;
 363         }
 364
 365         error = dpm_prepare(PMSG_FREEZE);
 366         if (error) {
 367                 dpm_complete(PMSG_RECOVER);
 368                 goto Thaw;
 369         }
 370
 371         suspend_console();
 372         pm_restrict_gfp_mask();
 373
 374         error = dpm_suspend(PMSG_FREEZE);
 375
 376         if (error || hibernation_test(TEST_DEVICES))
 377                 platform_recover(platform_mode);
 378         else
 379                 error = create_image(platform_mode);
 380
 381         /*
 382          * In the case that we call create_image() above, the control
 383          * returns here (1) after the image has been created or the
 384          * image creation has failed and (2) after a successful restore.
 385          */
 386
 387         /* We may need to release the preallocated image pages here. */
 388         if (error || !in_suspend)
 389                 swsusp_free();
 390
 391         msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
 392         dpm_resume(msg);
 393
 394         if (error || !in_suspend)
 395                 pm_restore_gfp_mask();
 396
 397         resume_console();
 398         dpm_complete(msg);
 399
 400  Close:
 401         platform_end(platform_mode);
 402         return error;
 403
 404  Thaw:
 405         thaw_kernel_threads();
 406  Cleanup:
 407         swsusp_free();
 408         goto Close;
 409 }
 410
 411 /**
 412  * resume_target_kernel - Restore system state from a hibernation image.
 413  * @platform_mode: Whether or not to use the platform driver.
 414  *
 415  * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
 416  * contents of highmem that have not been restored yet from the image and run
 417  * the low-level code that will restore the remaining contents of memory and
 418  * switch to the just restored target kernel.
 419  */
 420 static int resume_target_kernel(bool platform_mode)
 421 {
 422         int error;
 423
 424         error = dpm_suspend_end(PMSG_QUIESCE);
 425         if (error) {
 426                 printk(KERN_ERR "PM: Some devices failed to power down, "
 427                         "aborting resume\n");
 428                 return error;
 429         }
 430
 431         error = platform_pre_restore(platform_mode);
 432         if (error)
 433                 goto Cleanup;
 434
 435         error = disable_nonboot_cpus();
 436         if (error)
 437                 goto Enable_cpus;
 438
 439         local_irq_disable();
 440
 441         error = syscore_suspend();
 442         if (error)
 443                 goto Enable_irqs;
 444
 445         save_processor_state();
 446         error = restore_highmem();
 447         if (!error) {
 448                 error = swsusp_arch_resume();
 449                 /*
 450                  * The code below is only ever reached in case of a failure.
 451                  * Otherwise, execution continues at the place where
 452                  * swsusp_arch_suspend() was called.
 453                  */
 454                 BUG_ON(!error);
 455                 /*
 456                  * This call to restore_highmem() reverts the changes made by
 457                  * the previous one.
 458                  */
 459                 restore_highmem();
 460         }
 461         /*
 462          * The only reason why swsusp_arch_resume() can fail is memory being
 463          * very tight, so we have to free it as soon as we can to avoid
 464          * subsequent failures.
 465          */
 466         swsusp_free();
 467         restore_processor_state();
 468         touch_softlockup_watchdog();
 469
 470         syscore_resume();
 471
 472  Enable_irqs:
 473         local_irq_enable();
 474
 475  Enable_cpus:
 476         enable_nonboot_cpus();
 477
 478  Cleanup:
 479         platform_restore_cleanup(platform_mode);
 480
 481         dpm_resume_start(PMSG_RECOVER);
 482
 483         return error;
 484 }
 485
 486 /**
 487  * hibernation_restore - Quiesce devices and restore from a hibernation image.
 488  * @platform_mode: If set, use platform driver to prepare for the transition.
 489  *
 490  * This routine must be called with pm_mutex held.  If it is successful, control
 491  * reappears in the restored target kernel in hibernation_snapshot().
 492  */
 493 int hibernation_restore(int platform_mode)
 494 {
 495         int error;
 496
 497         pm_prepare_console();
 498         suspend_console();
 499         pm_restrict_gfp_mask();
 500         error = dpm_suspend_start(PMSG_QUIESCE);
 501         if (!error) {
 502                 error = resume_target_kernel(platform_mode);
 503                 /*
 504                  * The above should either succeed and jump to the new kernel,
 505                  * or return with an error. Otherwise things are just
 506                  * undefined, so let's be paranoid.
 507                  */
 508                 BUG_ON(!error);
 509         }
 510         dpm_resume_end(PMSG_RECOVER);
 511         pm_restore_gfp_mask();
 512         resume_console();
 513         pm_restore_console();
 514         return error;
 515 }
 516
 517 /**
 518  * hibernation_platform_enter - Power off the system using the platform driver.
 519  */
 520 int hibernation_platform_enter(void)
 521 {
 522         int error;
 523
 524         if (!hibernation_ops)
 525                 return -ENOSYS;
 526
 527         /*
 528          * We have cancelled the power transition by running
 529          * hibernation_ops->finish() before saving the image, so we should let
 530          * the firmware know that we're going to enter the sleep state after all
 531          */
 532         error = hibernation_ops->begin();
 533         if (error)
 534                 goto Close;
 535
 536         entering_platform_hibernation = true;
 537         suspend_console();
 538         error = dpm_suspend_start(PMSG_HIBERNATE);
 539         if (error) {
 540                 if (hibernation_ops->recover)
 541                         hibernation_ops->recover();
 542                 goto Resume_devices;
 543         }
 544
 545         error = dpm_suspend_end(PMSG_HIBERNATE);
 546         if (error)
 547                 goto Resume_devices;
 548
 549         error = hibernation_ops->prepare();
 550         if (error)
 551                 goto Platform_finish;
 552
 553         error = disable_nonboot_cpus();
 554         if (error)
 555                 goto Platform_finish;
 556
 557         local_irq_disable();
 558         syscore_suspend();
 559         if (pm_wakeup_pending()) {
 560                 error = -EAGAIN;
 561                 goto Power_up;
 562         }
 563
 564         hibernation_ops->enter();
 565         /* We should never get here */
 566         while (1);
 567
 568  Power_up:
 569         syscore_resume();
 570         local_irq_enable();
 571         enable_nonboot_cpus();
 572
 573  Platform_finish:
 574         hibernation_ops->finish();
 575
 576         dpm_resume_start(PMSG_RESTORE);
 577
 578  Resume_devices:
 579         entering_platform_hibernation = false;
 580         dpm_resume_end(PMSG_RESTORE);
 581         resume_console();
 582
 583  Close:
 584         hibernation_ops->end();
 585
 586         return error;
 587 }
 588
 589 /**
 590  * power_down - Shut the machine down for hibernation.
 591  *
 592  * Use the platform driver, if configured, to put the system into the sleep
 593  * state corresponding to hibernation, or try to power it off or reboot,
 594  * depending on the value of hibernation_mode.
 595  */
 596 static void power_down(void)
 597 {
 598 #ifdef CONFIG_SUSPEND
 599         int error;
 600 #endif
 601
 602         switch (hibernation_mode) {
 603         case HIBERNATION_REBOOT:
 604                 kernel_restart(NULL);
 605                 break;
 606         case HIBERNATION_PLATFORM:
 607                 hibernation_platform_enter();
 608         case HIBERNATION_SHUTDOWN:
 609                 if (pm_power_off)
 610                         kernel_power_off();
 611                 break;
 612 #ifdef CONFIG_SUSPEND
 613         case HIBERNATION_SUSPEND:
 614                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 615                 if (error) {
 616                         if (hibernation_ops)
 617                                 hibernation_mode = HIBERNATION_PLATFORM;
 618                         else
 619                                 hibernation_mode = HIBERNATION_SHUTDOWN;
 620                         power_down();
 621                 }
 622                 /*
 623                  * Restore swap signature.
 624                  */
 625                 error = swsusp_unmark();
 626                 if (error)
 627                         printk(KERN_ERR "PM: Swap will be unusable! "
 628                                         "Try swapon -a.\n");
 629                 return;
 630 #endif
 631         }
 632         kernel_halt();
 633         /*
 634          * Valid image is on the disk, if we continue we risk serious data
 635          * corruption after resume.
 636          */
 637         printk(KERN_CRIT "PM: Please power down manually\n");
 638         while (1)
 639                 cpu_relax();
 640 }
 641
 642 /**
 643  * hibernate - Carry out system hibernation, including saving the image.
 644  */
 645 int hibernate(void)
 646 {
 647         int error;
 648
 649         if (!hibernation_available()) {
 650                 pr_debug("PM: Hibernation not available.\n");
 651                 return -EPERM;
 652         }
 653
 654         lock_system_sleep();
 655         /* The snapshot device should not be opened while we're running */
 656         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 657                 error = -EBUSY;
 658                 goto Unlock;
 659         }
 660
 661         pm_prepare_console();
 662         error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
 663         if (error)
 664                 goto Exit;
 665
 666         printk(KERN_INFO "PM: Syncing filesystems ... ");
 667         sys_sync();
 668         printk("done.\n");
 669
 670         error = freeze_processes();
 671         if (error)
 672                 goto Exit;
 673
 674         lock_device_hotplug();
 675         /* Allocate memory management structures */
 676         error = create_basic_memory_bitmaps();
 677         if (error)
 678                 goto Thaw;
 679
 680         error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
 681         if (error || freezer_test_done)
 682                 goto Free_bitmaps;
 683
 684         if (in_suspend) {
 685                 unsigned int flags = 0;
 686
 687                 if (hibernation_mode == HIBERNATION_PLATFORM)
 688                         flags |= SF_PLATFORM_MODE;
 689                 if (nocompress)
 690                         flags |= SF_NOCOMPRESS_MODE;
 691                 else
 692                         flags |= SF_CRC32_MODE;
 693
 694                 pr_debug("PM: writing image.\n");
 695                 error = swsusp_write(flags);
 696                 swsusp_free();
 697                 if (!error)
 698                         power_down();
 699                 in_suspend = 0;
 700                 pm_restore_gfp_mask();
 701         } else {
 702                 pr_debug("PM: Image restored successfully.\n");
 703         }
 704
 705  Free_bitmaps:
 706         free_basic_memory_bitmaps();
 707  Thaw:
 708         unlock_device_hotplug();
 709         thaw_processes();
 710
 711         /* Don't bother checking whether freezer_test_done is true */
 712         freezer_test_done = false;
 713  Exit:
 714         pm_notifier_call_chain(PM_POST_HIBERNATION);
 715         pm_restore_console();
 716         atomic_inc(&snapshot_device_available);
 717  Unlock:
 718         unlock_system_sleep();
 719         return error;
 720 }
 721
 722
 723 /**
 724  * software_resume - Resume from a saved hibernation image.
 725  *
 726  * This routine is called as a late initcall, when all devices have been
 727  * discovered and initialized already.
 728  *
 729  * The image reading code is called to see if there is a hibernation image
 730  * available for reading.  If that is the case, devices are quiesced and the
 731  * contents of memory is restored from the saved image.
 732  *
 733  * If this is successful, control reappears in the restored target kernel in
 734  * hibernation_snaphot() which returns to hibernate().  Otherwise, the routine
 735  * attempts to recover gracefully and make the kernel return to the normal mode
 736  * of operation.
 737  */
 738 static int software_resume(void)
 739 {
 740         int error;
 741         unsigned int flags;
 742
 743         /*
 744          * If the user said "noresume".. bail out early.
 745          */
 746         if (noresume || !hibernation_available())
 747                 return 0;
 748
 749         /*
 750          * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
 751          * is configured into the kernel. Since the regular hibernate
 752          * trigger path is via sysfs which takes a buffer mutex before
 753          * calling hibernate functions (which take pm_mutex) this can
 754          * cause lockdep to complain about a possible ABBA deadlock
 755          * which cannot happen since we're in the boot code here and
 756          * sysfs can't be invoked yet. Therefore, we use a subclass
 757          * here to avoid lockdep complaining.
 758          */
 759         mutex_lock_nested(&pm_mutex, SINGLE_DEPTH_NESTING);
 760
 761         if (swsusp_resume_device)
 762                 goto Check_image;
 763
 764         if (!strlen(resume_file)) {
 765                 error = -ENOENT;
 766                 goto Unlock;
 767         }
 768
 769         pr_debug("PM: Checking hibernation image partition %s\n", resume_file);
 770
 771         if (resume_delay) {
 772                 printk(KERN_INFO "Waiting %dsec before reading resume device...\n",
 773                         resume_delay);
 774                 ssleep(resume_delay);
 775         }
 776
 777         /* Check if the device is there */
 778         swsusp_resume_device = name_to_dev_t(resume_file);
 779
 780         /*
 781          * name_to_dev_t is ineffective to verify parition if resume_file is in
 782          * integer format. (e.g. major:minor)
 783          */
 784         if (isdigit(resume_file[0]) && resume_wait) {
 785                 int partno;
 786                 while (!get_gendisk(swsusp_resume_device, &partno))
 787                         msleep(10);
 788         }
 789
 790         if (!swsusp_resume_device) {
 791                 /*
 792                  * Some device discovery might still be in progress; we need
 793                  * to wait for this to finish.
 794                  */
 795                 wait_for_device_probe();
 796
 797                 if (resume_wait) {
 798                         while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
 799                                 msleep(10);
 800                         async_synchronize_full();
 801                 }
 802
 803                 swsusp_resume_device = name_to_dev_t(resume_file);
 804                 if (!swsusp_resume_device) {
 805                         error = -ENODEV;
 806                         goto Unlock;
 807                 }
 808         }
 809
 810  Check_image:
 811         pr_debug("PM: Hibernation image partition %d:%d present\n",
 812                 MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 813
 814         pr_debug("PM: Looking for hibernation image.\n");
 815         error = swsusp_check();
 816         if (error)
 817                 goto Unlock;
 818
 819         /* The snapshot device should not be opened while we're running */
 820         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 821                 error = -EBUSY;
 822                 swsusp_close(FMODE_READ);
 823                 goto Unlock;
 824         }
 825
 826         pm_prepare_console();
 827         error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
 828         if (error)
 829                 goto Close_Finish;
 830
 831         pr_debug("PM: Preparing processes for restore.\n");
 832         error = freeze_processes();
 833         if (error)
 834                 goto Close_Finish;
 835
 836         pr_debug("PM: Loading hibernation image.\n");
 837
 838         lock_device_hotplug();
 839         error = create_basic_memory_bitmaps();
 840         if (error)
 841                 goto Thaw;
 842
 843         error = swsusp_read(&flags);
 844         swsusp_close(FMODE_READ);
 845         if (!error)
 846                 hibernation_restore(flags & SF_PLATFORM_MODE);
 847
 848         printk(KERN_ERR "PM: Failed to load hibernation image, recovering.\n");
 849         swsusp_free();
 850         free_basic_memory_bitmaps();
 851  Thaw:
 852         unlock_device_hotplug();
 853         thaw_processes();
 854  Finish:
 855         pm_notifier_call_chain(PM_POST_RESTORE);
 856         pm_restore_console();
 857         atomic_inc(&snapshot_device_available);
 858         /* For success case, the suspend path will release the lock */
 859  Unlock:
 860         mutex_unlock(&pm_mutex);
 861         pr_debug("PM: Hibernation image not present or could not be loaded.\n");
 862         return error;
 863  Close_Finish:
 864         swsusp_close(FMODE_READ);
 865         goto Finish;
 866 }
 867
 868 late_initcall_sync(software_resume);
 869
 870
 871 static const char * const hibernation_modes[] = {
 872         [HIBERNATION_PLATFORM]  = "platform",
 873         [HIBERNATION_SHUTDOWN]  = "shutdown",
 874         [HIBERNATION_REBOOT]    = "reboot",
 875 #ifdef CONFIG_SUSPEND
 876         [HIBERNATION_SUSPEND]   = "suspend",
 877 #endif
 878 };
 879
 880 /*
 881  * /sys/power/disk - Control hibernation mode.
 882  *
 883  * Hibernation can be handled in several ways.  There are a few different ways
 884  * to put the system into the sleep state: using the platform driver (e.g. ACPI
 885  * or other hibernation_ops), powering it off or rebooting it (for testing
 886  * mostly).
 887  *
 888  * The sysfs file /sys/power/disk provides an interface for selecting the
 889  * hibernation mode to use.  Reading from this file causes the available modes
 890  * to be printed.  There are 3 modes that can be supported:
 891  *
 892  *      'platform'
 893  *      'shutdown'
 894  *      'reboot'
 895  *
 896  * If a platform hibernation driver is in use, 'platform' will be supported
 897  * and will be used by default.  Otherwise, 'shutdown' will be used by default.
 898  * The selected option (i.e. the one corresponding to the current value of
 899  * hibernation_mode) is enclosed by a square bracket.
 900  *
 901  * To select a given hibernation mode it is necessary to write the mode's
 902  * string representation (as returned by reading from /sys/power/disk) back
 903  * into /sys/power/disk.
 904  */
 905
 906 static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
 907                          char *buf)
 908 {
 909         int i;
 910         char *start = buf;
 911
 912         if (!hibernation_available())
 913                 return sprintf(buf, "[disabled]\n");
 914
 915         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 916                 if (!hibernation_modes[i])
 917                         continue;
 918                 switch (i) {
 919                 case HIBERNATION_SHUTDOWN:
 920                 case HIBERNATION_REBOOT:
 921 #ifdef CONFIG_SUSPEND
 922                 case HIBERNATION_SUSPEND:
 923 #endif
 924                         break;
 925                 case HIBERNATION_PLATFORM:
 926                         if (hibernation_ops)
 927                                 break;
 928                         /* not a valid mode, continue with loop */
 929                         continue;
 930                 }
 931                 if (i == hibernation_mode)
 932                         buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
 933                 else
 934                         buf += sprintf(buf, "%s ", hibernation_modes[i]);
 935         }
 936         buf += sprintf(buf, "\n");
 937         return buf-start;
 938 }
 939
 940 static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
 941                           const char *buf, size_t n)
 942 {
 943         int error = 0;
 944         int i;
 945         int len;
 946         char *p;
 947         int mode = HIBERNATION_INVALID;
 948
 949         if (!hibernation_available())
 950                 return -EPERM;
 951
 952         p = memchr(buf, '\n', n);
 953         len = p ? p - buf : n;
 954
 955         lock_system_sleep();
 956         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 957                 if (len == strlen(hibernation_modes[i])
 958                     && !strncmp(buf, hibernation_modes[i], len)) {
 959                         mode = i;
 960                         break;
 961                 }
 962         }
 963         if (mode != HIBERNATION_INVALID) {
 964                 switch (mode) {
 965                 case HIBERNATION_SHUTDOWN:
 966                 case HIBERNATION_REBOOT:
 967 #ifdef CONFIG_SUSPEND
 968                 case HIBERNATION_SUSPEND:
 969 #endif
 970                         hibernation_mode = mode;
 971                         break;
 972                 case HIBERNATION_PLATFORM:
 973                         if (hibernation_ops)
 974                                 hibernation_mode = mode;
 975                         else
 976                                 error = -EINVAL;
 977                 }
 978         } else
 979                 error = -EINVAL;
 980
 981         if (!error)
 982                 pr_debug("PM: Hibernation mode set to '%s'\n",
 983                          hibernation_modes[mode]);
 984         unlock_system_sleep();
 985         return error ? error : n;
 986 }
 987
 988 power_attr(disk);
 989
 990 static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
 991                            char *buf)
 992 {
 993         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
 994                        MINOR(swsusp_resume_device));
 995 }
 996
 997 static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
 998                             const char *buf, size_t n)
 999 {
1000         dev_t res;
1001         int len = n;
1002         char *name;
1003
1004         if (len && buf[len-1] == '\n')
1005                 len--;
1006         name = kstrndup(buf, len, GFP_KERNEL);
1007         if (!name)
1008                 return -ENOMEM;
1009
1010         res = name_to_dev_t(name);
1011         kfree(name);
1012         if (!res)
1013                 return -EINVAL;
1014
1015         lock_system_sleep();
1016         swsusp_resume_device = res;
1017         unlock_system_sleep();
1018         printk(KERN_INFO "PM: Starting manual resume from disk\n");
1019         noresume = 0;
1020         software_resume();
1021         return n;
1022 }
1023
1024 power_attr(resume);
1025
1026 static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
1027                                char *buf)
1028 {
1029         return sprintf(buf, "%lu\n", image_size);
1030 }
1031
1032 static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
1033                                 const char *buf, size_t n)
1034 {
1035         unsigned long size;
1036
1037         if (sscanf(buf, "%lu", &size) == 1) {
1038                 image_size = size;
1039                 return n;
1040         }
1041
1042         return -EINVAL;
1043 }
1044
1045 power_attr(image_size);
1046
1047 static ssize_t reserved_size_show(struct kobject *kobj,
1048                                   struct kobj_attribute *attr, char *buf)
1049 {
1050         return sprintf(buf, "%lu\n", reserved_size);
1051 }
1052
1053 static ssize_t reserved_size_store(struct kobject *kobj,
1054                                    struct kobj_attribute *attr,
1055                                    const char *buf, size_t n)
1056 {
1057         unsigned long size;
1058
1059         if (sscanf(buf, "%lu", &size) == 1) {
1060                 reserved_size = size;
1061                 return n;
1062         }
1063
1064         return -EINVAL;
1065 }
1066
1067 power_attr(reserved_size);
1068
1069 static struct attribute * g[] = {
1070         &disk_attr.attr,
1071         &resume_attr.attr,
1072         &image_size_attr.attr,
1073         &reserved_size_attr.attr,
1074         NULL,
1075 };
1076
1077
1078 static struct attribute_group attr_group = {
1079         .attrs = g,
1080 };
1081
1082
1083 static int __init pm_disk_init(void)
1084 {
1085         return sysfs_create_group(power_kobj, &attr_group);
1086 }
1087
1088 core_initcall(pm_disk_init);
1089
1090
1091 static int __init resume_setup(char *str)
1092 {
1093         if (noresume)
1094                 return 1;
1095
1096         strncpy( resume_file, str, 255 );
1097         return 1;
1098 }
1099
1100 static int __init resume_offset_setup(char *str)
1101 {
1102         unsigned long long offset;
1103
1104         if (noresume)
1105                 return 1;
1106
1107         if (sscanf(str, "%llu", &offset) == 1)
1108                 swsusp_resume_block = offset;
1109
1110         return 1;
1111 }
1112
1113 static int __init hibernate_setup(char *str)
1114 {
1115         if (!strncmp(str, "noresume", 8))
1116                 noresume = 1;
1117         else if (!strncmp(str, "nocompress", 10))
1118                 nocompress = 1;
1119         else if (!strncmp(str, "no", 2)) {
1120                 noresume = 1;
1121                 nohibernate = 1;
1122         }
1123         return 1;
1124 }
1125
1126 static int __init noresume_setup(char *str)
1127 {
1128         noresume = 1;
1129         return 1;
1130 }
1131
1132 static int __init resumewait_setup(char *str)
1133 {
1134         resume_wait = 1;
1135         return 1;
1136 }
1137
1138 static int __init resumedelay_setup(char *str)
1139 {
1140         int rc = kstrtouint(str, 0, &resume_delay);
1141
1142         if (rc)
1143                 return rc;
1144         return 1;
1145 }
1146
1147 static int __init nohibernate_setup(char *str)
1148 {
1149         noresume = 1;
1150         nohibernate = 1;
1151         return 1;
1152 }
1153
1154 static int __init kaslr_nohibernate_setup(char *str)
1155 {
1156         return nohibernate_setup(str);
1157 }
1158
1159 __setup("noresume", noresume_setup);
1160 __setup("resume_offset=", resume_offset_setup);
1161 __setup("resume=", resume_setup);
1162 __setup("hibernate=", hibernate_setup);
1163 __setup("resumewait", resumewait_setup);
1164 __setup("resumedelay=", resumedelay_setup);
1165 __setup("nohibernate", nohibernate_setup);
1166 __setup("kaslr", kaslr_nohibernate_setup);