kernel/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         system_state = SYSTEM_SUSPEND;
 289
 290         error = syscore_suspend();
 291         if (error) {
 292                 printk(KERN_ERR "PM: Some system devices failed to power down, "
 293                         "aborting hibernation\n");
 294                 goto Enable_irqs;
 295         }
 296
 297         if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
 298                 goto Power_up;
 299
 300         in_suspend = 1;
 301         save_processor_state();
 302         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);
 303         error = swsusp_arch_suspend();
 304         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
 305         if (error)
 306                 printk(KERN_ERR "PM: Error %d creating hibernation image\n",
 307                         error);
 308         /* Restore control flow magically appears here */
 309         restore_processor_state();
 310         if (!in_suspend)
 311                 events_check_enabled = false;
 312
 313         platform_leave(platform_mode);
 314
 315  Power_up:
 316         syscore_resume();
 317
 318  Enable_irqs:
 319         system_state = SYSTEM_RUNNING;
 320         local_irq_enable();
 321
 322  Enable_cpus:
 323         enable_nonboot_cpus();
 324
 325  Platform_finish:
 326         platform_finish(platform_mode);
 327
 328         dpm_resume_start(in_suspend ?
 329                 (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
 330
 331         return error;
 332 }
 333
 334 /**
 335  * hibernation_snapshot - Quiesce devices and create a hibernation image.
 336  * @platform_mode: If set, use platform driver to prepare for the transition.
 337  *
 338  * This routine must be called with pm_mutex held.
 339  */
 340 int hibernation_snapshot(int platform_mode)
 341 {
 342         pm_message_t msg;
 343         int error;
 344
 345         error = platform_begin(platform_mode);
 346         if (error)
 347                 goto Close;
 348
 349         /* Preallocate image memory before shutting down devices. */
 350         error = hibernate_preallocate_memory();
 351         if (error)
 352                 goto Close;
 353
 354         error = freeze_kernel_threads();
 355         if (error)
 356                 goto Cleanup;
 357
 358         if (hibernation_test(TEST_FREEZER)) {
 359
 360                 /*
 361                  * Indicate to the caller that we are returning due to a
 362                  * successful freezer test.
 363                  */
 364                 freezer_test_done = true;
 365                 goto Thaw;
 366         }
 367
 368         error = dpm_prepare(PMSG_FREEZE);
 369         if (error) {
 370                 dpm_complete(PMSG_RECOVER);
 371                 goto Thaw;
 372         }
 373
 374         suspend_console();
 375         pm_restrict_gfp_mask();
 376
 377         error = dpm_suspend(PMSG_FREEZE);
 378
 379         if (error || hibernation_test(TEST_DEVICES))
 380                 platform_recover(platform_mode);
 381         else
 382                 error = create_image(platform_mode);
 383
 384         /*
 385          * In the case that we call create_image() above, the control
 386          * returns here (1) after the image has been created or the
 387          * image creation has failed and (2) after a successful restore.
 388          */
 389
 390         /* We may need to release the preallocated image pages here. */
 391         if (error || !in_suspend)
 392                 swsusp_free();
 393
 394         msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
 395         dpm_resume(msg);
 396
 397         if (error || !in_suspend)
 398                 pm_restore_gfp_mask();
 399
 400         resume_console();
 401         dpm_complete(msg);
 402
 403  Close:
 404         platform_end(platform_mode);
 405         return error;
 406
 407  Thaw:
 408         thaw_kernel_threads();
 409  Cleanup:
 410         swsusp_free();
 411         goto Close;
 412 }
 413
 414 /**
 415  * resume_target_kernel - Restore system state from a hibernation image.
 416  * @platform_mode: Whether or not to use the platform driver.
 417  *
 418  * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
 419  * contents of highmem that have not been restored yet from the image and run
 420  * the low-level code that will restore the remaining contents of memory and
 421  * switch to the just restored target kernel.
 422  */
 423 static int resume_target_kernel(bool platform_mode)
 424 {
 425         int error;
 426
 427         error = dpm_suspend_end(PMSG_QUIESCE);
 428         if (error) {
 429                 printk(KERN_ERR "PM: Some devices failed to power down, "
 430                         "aborting resume\n");
 431                 return error;
 432         }
 433
 434         error = platform_pre_restore(platform_mode);
 435         if (error)
 436                 goto Cleanup;
 437
 438         error = disable_nonboot_cpus();
 439         if (error)
 440                 goto Enable_cpus;
 441
 442         local_irq_disable();
 443         system_state = SYSTEM_SUSPEND;
 444
 445         error = syscore_suspend();
 446         if (error)
 447                 goto Enable_irqs;
 448
 449         save_processor_state();
 450         error = restore_highmem();
 451         if (!error) {
 452                 error = swsusp_arch_resume();
 453                 /*
 454                  * The code below is only ever reached in case of a failure.
 455                  * Otherwise, execution continues at the place where
 456                  * swsusp_arch_suspend() was called.
 457                  */
 458                 BUG_ON(!error);
 459                 /*
 460                  * This call to restore_highmem() reverts the changes made by
 461                  * the previous one.
 462                  */
 463                 restore_highmem();
 464         }
 465         /*
 466          * The only reason why swsusp_arch_resume() can fail is memory being
 467          * very tight, so we have to free it as soon as we can to avoid
 468          * subsequent failures.
 469          */
 470         swsusp_free();
 471         restore_processor_state();
 472         touch_softlockup_watchdog();
 473
 474         syscore_resume();
 475
 476  Enable_irqs:
 477         system_state = SYSTEM_RUNNING;
 478         local_irq_enable();
 479
 480  Enable_cpus:
 481         enable_nonboot_cpus();
 482
 483  Cleanup:
 484         platform_restore_cleanup(platform_mode);
 485
 486         dpm_resume_start(PMSG_RECOVER);
 487
 488         return error;
 489 }
 490
 491 /**
 492  * hibernation_restore - Quiesce devices and restore from a hibernation image.
 493  * @platform_mode: If set, use platform driver to prepare for the transition.
 494  *
 495  * This routine must be called with pm_mutex held.  If it is successful, control
 496  * reappears in the restored target kernel in hibernation_snapshot().
 497  */
 498 int hibernation_restore(int platform_mode)
 499 {
 500         int error;
 501
 502         pm_prepare_console();
 503         suspend_console();
 504         pm_restrict_gfp_mask();
 505         error = dpm_suspend_start(PMSG_QUIESCE);
 506         if (!error) {
 507                 error = resume_target_kernel(platform_mode);
 508                 /*
 509                  * The above should either succeed and jump to the new kernel,
 510                  * or return with an error. Otherwise things are just
 511                  * undefined, so let's be paranoid.
 512                  */
 513                 BUG_ON(!error);
 514         }
 515         dpm_resume_end(PMSG_RECOVER);
 516         pm_restore_gfp_mask();
 517         resume_console();
 518         pm_restore_console();
 519         return error;
 520 }
 521
 522 /**
 523  * hibernation_platform_enter - Power off the system using the platform driver.
 524  */
 525 int hibernation_platform_enter(void)
 526 {
 527         int error;
 528
 529         if (!hibernation_ops)
 530                 return -ENOSYS;
 531
 532         /*
 533          * We have cancelled the power transition by running
 534          * hibernation_ops->finish() before saving the image, so we should let
 535          * the firmware know that we're going to enter the sleep state after all
 536          */
 537         error = hibernation_ops->begin();
 538         if (error)
 539                 goto Close;
 540
 541         entering_platform_hibernation = true;
 542         suspend_console();
 543         error = dpm_suspend_start(PMSG_HIBERNATE);
 544         if (error) {
 545                 if (hibernation_ops->recover)
 546                         hibernation_ops->recover();
 547                 goto Resume_devices;
 548         }
 549
 550         error = dpm_suspend_end(PMSG_HIBERNATE);
 551         if (error)
 552                 goto Resume_devices;
 553
 554         error = hibernation_ops->prepare();
 555         if (error)
 556                 goto Platform_finish;
 557
 558         error = disable_nonboot_cpus();
 559         if (error)
 560                 goto Platform_finish;
 561
 562         local_irq_disable();
 563         system_state = SYSTEM_SUSPEND;
 564         syscore_suspend();
 565         if (pm_wakeup_pending()) {
 566                 error = -EAGAIN;
 567                 goto Power_up;
 568         }
 569
 570         hibernation_ops->enter();
 571         /* We should never get here */
 572         while (1);
 573
 574  Power_up:
 575         syscore_resume();
 576         system_state = SYSTEM_RUNNING;
 577         local_irq_enable();
 578         enable_nonboot_cpus();
 579
 580  Platform_finish:
 581         hibernation_ops->finish();
 582
 583         dpm_resume_start(PMSG_RESTORE);
 584
 585  Resume_devices:
 586         entering_platform_hibernation = false;
 587         dpm_resume_end(PMSG_RESTORE);
 588         resume_console();
 589
 590  Close:
 591         hibernation_ops->end();
 592
 593         return error;
 594 }
 595
 596 /**
 597  * power_down - Shut the machine down for hibernation.
 598  *
 599  * Use the platform driver, if configured, to put the system into the sleep
 600  * state corresponding to hibernation, or try to power it off or reboot,
 601  * depending on the value of hibernation_mode.
 602  */
 603 static void power_down(void)
 604 {
 605 #ifdef CONFIG_SUSPEND
 606         int error;
 607 #endif
 608
 609         switch (hibernation_mode) {
 610         case HIBERNATION_REBOOT:
 611                 kernel_restart(NULL);
 612                 break;
 613         case HIBERNATION_PLATFORM:
 614                 hibernation_platform_enter();
 615         case HIBERNATION_SHUTDOWN:
 616                 if (pm_power_off)
 617                         kernel_power_off();
 618                 break;
 619 #ifdef CONFIG_SUSPEND
 620         case HIBERNATION_SUSPEND:
 621                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
 622                 if (error) {
 623                         if (hibernation_ops)
 624                                 hibernation_mode = HIBERNATION_PLATFORM;
 625                         else
 626                                 hibernation_mode = HIBERNATION_SHUTDOWN;
 627                         power_down();
 628                 }
 629                 /*
 630                  * Restore swap signature.
 631                  */
 632                 error = swsusp_unmark();
 633                 if (error)
 634                         printk(KERN_ERR "PM: Swap will be unusable! "
 635                                         "Try swapon -a.\n");
 636                 return;
 637 #endif
 638         }
 639         kernel_halt();
 640         /*
 641          * Valid image is on the disk, if we continue we risk serious data
 642          * corruption after resume.
 643          */
 644         printk(KERN_CRIT "PM: Please power down manually\n");
 645         while (1)
 646                 cpu_relax();
 647 }
 648
 649 /**
 650  * hibernate - Carry out system hibernation, including saving the image.
 651  */
 652 int hibernate(void)
 653 {
 654         int error;
 655
 656         if (!hibernation_available()) {
 657                 pr_debug("PM: Hibernation not available.\n");
 658                 return -EPERM;
 659         }
 660
 661         lock_system_sleep();
 662         /* The snapshot device should not be opened while we're running */
 663         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 664                 error = -EBUSY;
 665                 goto Unlock;
 666         }
 667
 668         pm_prepare_console();
 669         error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
 670         if (error)
 671                 goto Exit;
 672
 673         printk(KERN_INFO "PM: Syncing filesystems ... ");
 674         sys_sync();
 675         printk("done.\n");
 676
 677         error = freeze_processes();
 678         if (error)
 679                 goto Exit;
 680
 681         lock_device_hotplug();
 682         /* Allocate memory management structures */
 683         error = create_basic_memory_bitmaps();
 684         if (error)
 685                 goto Thaw;
 686
 687         error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
 688         if (error || freezer_test_done)
 689                 goto Free_bitmaps;
 690
 691         if (in_suspend) {
 692                 unsigned int flags = 0;
 693
 694                 if (hibernation_mode == HIBERNATION_PLATFORM)
 695                         flags |= SF_PLATFORM_MODE;
 696                 if (nocompress)
 697                         flags |= SF_NOCOMPRESS_MODE;
 698                 else
 699                         flags |= SF_CRC32_MODE;
 700
 701                 pr_debug("PM: writing image.\n");
 702                 error = swsusp_write(flags);
 703                 swsusp_free();
 704                 if (!error)
 705                         power_down();
 706                 in_suspend = 0;
 707                 pm_restore_gfp_mask();
 708         } else {
 709                 pr_debug("PM: Image restored successfully.\n");
 710         }
 711
 712  Free_bitmaps:
 713         free_basic_memory_bitmaps();
 714  Thaw:
 715         unlock_device_hotplug();
 716         thaw_processes();
 717
 718         /* Don't bother checking whether freezer_test_done is true */
 719         freezer_test_done = false;
 720  Exit:
 721         pm_notifier_call_chain(PM_POST_HIBERNATION);
 722         pm_restore_console();
 723         atomic_inc(&snapshot_device_available);
 724  Unlock:
 725         unlock_system_sleep();
 726         return error;
 727 }
 728
 729
 730 /**
 731  * software_resume - Resume from a saved hibernation image.
 732  *
 733  * This routine is called as a late initcall, when all devices have been
 734  * discovered and initialized already.
 735  *
 736  * The image reading code is called to see if there is a hibernation image
 737  * available for reading.  If that is the case, devices are quiesced and the
 738  * contents of memory is restored from the saved image.
 739  *
 740  * If this is successful, control reappears in the restored target kernel in
 741  * hibernation_snaphot() which returns to hibernate().  Otherwise, the routine
 742  * attempts to recover gracefully and make the kernel return to the normal mode
 743  * of operation.
 744  */
 745 static int software_resume(void)
 746 {
 747         int error;
 748         unsigned int flags;
 749
 750         /*
 751          * If the user said "noresume".. bail out early.
 752          */
 753         if (noresume || !hibernation_available())
 754                 return 0;
 755
 756         /*
 757          * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
 758          * is configured into the kernel. Since the regular hibernate
 759          * trigger path is via sysfs which takes a buffer mutex before
 760          * calling hibernate functions (which take pm_mutex) this can
 761          * cause lockdep to complain about a possible ABBA deadlock
 762          * which cannot happen since we're in the boot code here and
 763          * sysfs can't be invoked yet. Therefore, we use a subclass
 764          * here to avoid lockdep complaining.
 765          */
 766         mutex_lock_nested(&pm_mutex, SINGLE_DEPTH_NESTING);
 767
 768         if (swsusp_resume_device)
 769                 goto Check_image;
 770
 771         if (!strlen(resume_file)) {
 772                 error = -ENOENT;
 773                 goto Unlock;
 774         }
 775
 776         pr_debug("PM: Checking hibernation image partition %s\n", resume_file);
 777
 778         if (resume_delay) {
 779                 printk(KERN_INFO "Waiting %dsec before reading resume device...\n",
 780                         resume_delay);
 781                 ssleep(resume_delay);
 782         }
 783
 784         /* Check if the device is there */
 785         swsusp_resume_device = name_to_dev_t(resume_file);
 786
 787         /*
 788          * name_to_dev_t is ineffective to verify parition if resume_file is in
 789          * integer format. (e.g. major:minor)
 790          */
 791         if (isdigit(resume_file[0]) && resume_wait) {
 792                 int partno;
 793                 while (!get_gendisk(swsusp_resume_device, &partno))
 794                         msleep(10);
 795         }
 796
 797         if (!swsusp_resume_device) {
 798                 /*
 799                  * Some device discovery might still be in progress; we need
 800                  * to wait for this to finish.
 801                  */
 802                 wait_for_device_probe();
 803
 804                 if (resume_wait) {
 805                         while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
 806                                 msleep(10);
 807                         async_synchronize_full();
 808                 }
 809
 810                 swsusp_resume_device = name_to_dev_t(resume_file);
 811                 if (!swsusp_resume_device) {
 812                         error = -ENODEV;
 813                         goto Unlock;
 814                 }
 815         }
 816
 817  Check_image:
 818         pr_debug("PM: Hibernation image partition %d:%d present\n",
 819                 MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 820
 821         pr_debug("PM: Looking for hibernation image.\n");
 822         error = swsusp_check();
 823         if (error)
 824                 goto Unlock;
 825
 826         /* The snapshot device should not be opened while we're running */
 827         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
 828                 error = -EBUSY;
 829                 swsusp_close(FMODE_READ);
 830                 goto Unlock;
 831         }
 832
 833         pm_prepare_console();
 834         error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
 835         if (error)
 836                 goto Close_Finish;
 837
 838         pr_debug("PM: Preparing processes for restore.\n");
 839         error = freeze_processes();
 840         if (error)
 841                 goto Close_Finish;
 842
 843         pr_debug("PM: Loading hibernation image.\n");
 844
 845         lock_device_hotplug();
 846         error = create_basic_memory_bitmaps();
 847         if (error)
 848                 goto Thaw;
 849
 850         error = swsusp_read(&flags);
 851         swsusp_close(FMODE_READ);
 852         if (!error)
 853                 hibernation_restore(flags & SF_PLATFORM_MODE);
 854
 855         printk(KERN_ERR "PM: Failed to load hibernation image, recovering.\n");
 856         swsusp_free();
 857         free_basic_memory_bitmaps();
 858  Thaw:
 859         unlock_device_hotplug();
 860         thaw_processes();
 861  Finish:
 862         pm_notifier_call_chain(PM_POST_RESTORE);
 863         pm_restore_console();
 864         atomic_inc(&snapshot_device_available);
 865         /* For success case, the suspend path will release the lock */
 866  Unlock:
 867         mutex_unlock(&pm_mutex);
 868         pr_debug("PM: Hibernation image not present or could not be loaded.\n");
 869         return error;
 870  Close_Finish:
 871         swsusp_close(FMODE_READ);
 872         goto Finish;
 873 }
 874
 875 late_initcall_sync(software_resume);
 876
 877
 878 static const char * const hibernation_modes[] = {
 879         [HIBERNATION_PLATFORM]  = "platform",
 880         [HIBERNATION_SHUTDOWN]  = "shutdown",
 881         [HIBERNATION_REBOOT]    = "reboot",
 882 #ifdef CONFIG_SUSPEND
 883         [HIBERNATION_SUSPEND]   = "suspend",
 884 #endif
 885 };
 886
 887 /*
 888  * /sys/power/disk - Control hibernation mode.
 889  *
 890  * Hibernation can be handled in several ways.  There are a few different ways
 891  * to put the system into the sleep state: using the platform driver (e.g. ACPI
 892  * or other hibernation_ops), powering it off or rebooting it (for testing
 893  * mostly).
 894  *
 895  * The sysfs file /sys/power/disk provides an interface for selecting the
 896  * hibernation mode to use.  Reading from this file causes the available modes
 897  * to be printed.  There are 3 modes that can be supported:
 898  *
 899  *      'platform'
 900  *      'shutdown'
 901  *      'reboot'
 902  *
 903  * If a platform hibernation driver is in use, 'platform' will be supported
 904  * and will be used by default.  Otherwise, 'shutdown' will be used by default.
 905  * The selected option (i.e. the one corresponding to the current value of
 906  * hibernation_mode) is enclosed by a square bracket.
 907  *
 908  * To select a given hibernation mode it is necessary to write the mode's
 909  * string representation (as returned by reading from /sys/power/disk) back
 910  * into /sys/power/disk.
 911  */
 912
 913 static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
 914                          char *buf)
 915 {
 916         int i;
 917         char *start = buf;
 918
 919         if (!hibernation_available())
 920                 return sprintf(buf, "[disabled]\n");
 921
 922         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 923                 if (!hibernation_modes[i])
 924                         continue;
 925                 switch (i) {
 926                 case HIBERNATION_SHUTDOWN:
 927                 case HIBERNATION_REBOOT:
 928 #ifdef CONFIG_SUSPEND
 929                 case HIBERNATION_SUSPEND:
 930 #endif
 931                         break;
 932                 case HIBERNATION_PLATFORM:
 933                         if (hibernation_ops)
 934                                 break;
 935                         /* not a valid mode, continue with loop */
 936                         continue;
 937                 }
 938                 if (i == hibernation_mode)
 939                         buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
 940                 else
 941                         buf += sprintf(buf, "%s ", hibernation_modes[i]);
 942         }
 943         buf += sprintf(buf, "\n");
 944         return buf-start;
 945 }
 946
 947 static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
 948                           const char *buf, size_t n)
 949 {
 950         int error = 0;
 951         int i;
 952         int len;
 953         char *p;
 954         int mode = HIBERNATION_INVALID;
 955
 956         if (!hibernation_available())
 957                 return -EPERM;
 958
 959         p = memchr(buf, '\n', n);
 960         len = p ? p - buf : n;
 961
 962         lock_system_sleep();
 963         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
 964                 if (len == strlen(hibernation_modes[i])
 965                     && !strncmp(buf, hibernation_modes[i], len)) {
 966                         mode = i;
 967                         break;
 968                 }
 969         }
 970         if (mode != HIBERNATION_INVALID) {
 971                 switch (mode) {
 972                 case HIBERNATION_SHUTDOWN:
 973                 case HIBERNATION_REBOOT:
 974 #ifdef CONFIG_SUSPEND
 975                 case HIBERNATION_SUSPEND:
 976 #endif
 977                         hibernation_mode = mode;
 978                         break;
 979                 case HIBERNATION_PLATFORM:
 980                         if (hibernation_ops)
 981                                 hibernation_mode = mode;
 982                         else
 983                                 error = -EINVAL;
 984                 }
 985         } else
 986                 error = -EINVAL;
 987
 988         if (!error)
 989                 pr_debug("PM: Hibernation mode set to '%s'\n",
 990                          hibernation_modes[mode]);
 991         unlock_system_sleep();
 992         return error ? error : n;
 993 }
 994
 995 power_attr(disk);
 996
 997 static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
 998                            char *buf)
 999 {
1000         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
1001                        MINOR(swsusp_resume_device));
1002 }
1003
1004 static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
1005                             const char *buf, size_t n)
1006 {
1007         dev_t res;
1008         int len = n;
1009         char *name;
1010
1011         if (len && buf[len-1] == '\n')
1012                 len--;
1013         name = kstrndup(buf, len, GFP_KERNEL);
1014         if (!name)
1015                 return -ENOMEM;
1016
1017         res = name_to_dev_t(name);
1018         kfree(name);
1019         if (!res)
1020                 return -EINVAL;
1021
1022         lock_system_sleep();
1023         swsusp_resume_device = res;
1024         unlock_system_sleep();
1025         printk(KERN_INFO "PM: Starting manual resume from disk\n");
1026         noresume = 0;
1027         software_resume();
1028         return n;
1029 }
1030
1031 power_attr(resume);
1032
1033 static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
1034                                char *buf)
1035 {
1036         return sprintf(buf, "%lu\n", image_size);
1037 }
1038
1039 static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
1040                                 const char *buf, size_t n)
1041 {
1042         unsigned long size;
1043
1044         if (sscanf(buf, "%lu", &size) == 1) {
1045                 image_size = size;
1046                 return n;
1047         }
1048
1049         return -EINVAL;
1050 }
1051
1052 power_attr(image_size);
1053
1054 static ssize_t reserved_size_show(struct kobject *kobj,
1055                                   struct kobj_attribute *attr, char *buf)
1056 {
1057         return sprintf(buf, "%lu\n", reserved_size);
1058 }
1059
1060 static ssize_t reserved_size_store(struct kobject *kobj,
1061                                    struct kobj_attribute *attr,
1062                                    const char *buf, size_t n)
1063 {
1064         unsigned long size;
1065
1066         if (sscanf(buf, "%lu", &size) == 1) {
1067                 reserved_size = size;
1068                 return n;
1069         }
1070
1071         return -EINVAL;
1072 }
1073
1074 power_attr(reserved_size);
1075
1076 static struct attribute * g[] = {
1077         &disk_attr.attr,
1078         &resume_attr.attr,
1079         &image_size_attr.attr,
1080         &reserved_size_attr.attr,
1081         NULL,
1082 };
1083
1084
1085 static struct attribute_group attr_group = {
1086         .attrs = g,
1087 };
1088
1089
1090 static int __init pm_disk_init(void)
1091 {
1092         return sysfs_create_group(power_kobj, &attr_group);
1093 }
1094
1095 core_initcall(pm_disk_init);
1096
1097
1098 static int __init resume_setup(char *str)
1099 {
1100         if (noresume)
1101                 return 1;
1102
1103         strncpy( resume_file, str, 255 );
1104         return 1;
1105 }
1106
1107 static int __init resume_offset_setup(char *str)
1108 {
1109         unsigned long long offset;
1110
1111         if (noresume)
1112                 return 1;
1113
1114         if (sscanf(str, "%llu", &offset) == 1)
1115                 swsusp_resume_block = offset;
1116
1117         return 1;
1118 }
1119
1120 static int __init hibernate_setup(char *str)
1121 {
1122         if (!strncmp(str, "noresume", 8))
1123                 noresume = 1;
1124         else if (!strncmp(str, "nocompress", 10))
1125                 nocompress = 1;
1126         else if (!strncmp(str, "no", 2)) {
1127                 noresume = 1;
1128                 nohibernate = 1;
1129         }
1130         return 1;
1131 }
1132
1133 static int __init noresume_setup(char *str)
1134 {
1135         noresume = 1;
1136         return 1;
1137 }
1138
1139 static int __init resumewait_setup(char *str)
1140 {
1141         resume_wait = 1;
1142         return 1;
1143 }
1144
1145 static int __init resumedelay_setup(char *str)
1146 {
1147         int rc = kstrtouint(str, 0, &resume_delay);
1148
1149         if (rc)
1150                 return rc;
1151         return 1;
1152 }
1153
1154 static int __init nohibernate_setup(char *str)
1155 {
1156         noresume = 1;
1157         nohibernate = 1;
1158         return 1;
1159 }
1160
1161 static int __init kaslr_nohibernate_setup(char *str)
1162 {
1163         return nohibernate_setup(str);
1164 }
1165
1166 __setup("noresume", noresume_setup);
1167 __setup("resume_offset=", resume_offset_setup);
1168 __setup("resume=", resume_setup);
1169 __setup("hibernate=", hibernate_setup);
1170 __setup("resumewait", resumewait_setup);
1171 __setup("resumedelay=", resumedelay_setup);
1172 __setup("nohibernate", nohibernate_setup);
1173 __setup("kaslr", kaslr_nohibernate_setup);