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TOMOYO Linux Cross Reference
Linux/kernel/power/hibernate.c

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  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 = disable_nonboot_cpus();
285         if (error || hibernation_test(TEST_CPUS))
286                 goto Enable_cpus;
287 
288         local_irq_disable();
289 
290         error = syscore_suspend();
291         if (error) {
292                 pr_err("Some system devices failed to power down, aborting hibernation\n");
293                 goto Enable_irqs;
294         }
295 
296         if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
297                 goto Power_up;
298 
299         in_suspend = 1;
300         save_processor_state();
301         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);
302         error = swsusp_arch_suspend();
303         /* Restore control flow magically appears here */
304         restore_processor_state();
305         trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
306         if (error)
307                 pr_err("Error %d creating hibernation image\n", error);
308 
309         if (!in_suspend) {
310                 events_check_enabled = false;
311                 clear_free_pages();
312         }
313 
314         platform_leave(platform_mode);
315 
316  Power_up:
317         syscore_resume();
318 
319  Enable_irqs:
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         pm_suspend_clear_flags();
346         error = platform_begin(platform_mode);
347         if (error)
348                 goto Close;
349 
350         /* Preallocate image memory before shutting down devices. */
351         error = hibernate_preallocate_memory();
352         if (error)
353                 goto Close;
354 
355         error = freeze_kernel_threads();
356         if (error)
357                 goto Cleanup;
358 
359         if (hibernation_test(TEST_FREEZER)) {
360 
361                 /*
362                  * Indicate to the caller that we are returning due to a
363                  * successful freezer test.
364                  */
365                 freezer_test_done = true;
366                 goto Thaw;
367         }
368 
369         error = dpm_prepare(PMSG_FREEZE);
370         if (error) {
371                 dpm_complete(PMSG_RECOVER);
372                 goto Thaw;
373         }
374 
375         suspend_console();
376         pm_restrict_gfp_mask();
377 
378         error = dpm_suspend(PMSG_FREEZE);
379 
380         if (error || hibernation_test(TEST_DEVICES))
381                 platform_recover(platform_mode);
382         else
383                 error = create_image(platform_mode);
384 
385         /*
386          * In the case that we call create_image() above, the control
387          * returns here (1) after the image has been created or the
388          * image creation has failed and (2) after a successful restore.
389          */
390 
391         /* We may need to release the preallocated image pages here. */
392         if (error || !in_suspend)
393                 swsusp_free();
394 
395         msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
396         dpm_resume(msg);
397 
398         if (error || !in_suspend)
399                 pm_restore_gfp_mask();
400 
401         resume_console();
402         dpm_complete(msg);
403 
404  Close:
405         platform_end(platform_mode);
406         return error;
407 
408  Thaw:
409         thaw_kernel_threads();
410  Cleanup:
411         swsusp_free();
412         goto Close;
413 }
414 
415 int __weak hibernate_resume_nonboot_cpu_disable(void)
416 {
417         return disable_nonboot_cpus();
418 }
419 
420 /**
421  * resume_target_kernel - Restore system state from a hibernation image.
422  * @platform_mode: Whether or not to use the platform driver.
423  *
424  * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
425  * contents of highmem that have not been restored yet from the image and run
426  * the low-level code that will restore the remaining contents of memory and
427  * switch to the just restored target kernel.
428  */
429 static int resume_target_kernel(bool platform_mode)
430 {
431         int error;
432 
433         error = dpm_suspend_end(PMSG_QUIESCE);
434         if (error) {
435                 pr_err("Some devices failed to power down, aborting resume\n");
436                 return error;
437         }
438 
439         error = platform_pre_restore(platform_mode);
440         if (error)
441                 goto Cleanup;
442 
443         error = hibernate_resume_nonboot_cpu_disable();
444         if (error)
445                 goto Enable_cpus;
446 
447         local_irq_disable();
448 
449         error = syscore_suspend();
450         if (error)
451                 goto Enable_irqs;
452 
453         save_processor_state();
454         error = restore_highmem();
455         if (!error) {
456                 error = swsusp_arch_resume();
457                 /*
458                  * The code below is only ever reached in case of a failure.
459                  * Otherwise, execution continues at the place where
460                  * swsusp_arch_suspend() was called.
461                  */
462                 BUG_ON(!error);
463                 /*
464                  * This call to restore_highmem() reverts the changes made by
465                  * the previous one.
466                  */
467                 restore_highmem();
468         }
469         /*
470          * The only reason why swsusp_arch_resume() can fail is memory being
471          * very tight, so we have to free it as soon as we can to avoid
472          * subsequent failures.
473          */
474         swsusp_free();
475         restore_processor_state();
476         touch_softlockup_watchdog();
477 
478         syscore_resume();
479 
480  Enable_irqs:
481         local_irq_enable();
482 
483  Enable_cpus:
484         enable_nonboot_cpus();
485 
486  Cleanup:
487         platform_restore_cleanup(platform_mode);
488 
489         dpm_resume_start(PMSG_RECOVER);
490 
491         return error;
492 }
493 
494 /**
495  * hibernation_restore - Quiesce devices and restore from a hibernation image.
496  * @platform_mode: If set, use platform driver to prepare for the transition.
497  *
498  * This routine must be called with pm_mutex held.  If it is successful, control
499  * reappears in the restored target kernel in hibernation_snapshot().
500  */
501 int hibernation_restore(int platform_mode)
502 {
503         int error;
504 
505         pm_prepare_console();
506         suspend_console();
507         pm_restrict_gfp_mask();
508         error = dpm_suspend_start(PMSG_QUIESCE);
509         if (!error) {
510                 error = resume_target_kernel(platform_mode);
511                 /*
512                  * The above should either succeed and jump to the new kernel,
513                  * or return with an error. Otherwise things are just
514                  * undefined, so let's be paranoid.
515                  */
516                 BUG_ON(!error);
517         }
518         dpm_resume_end(PMSG_RECOVER);
519         pm_restore_gfp_mask();
520         resume_console();
521         pm_restore_console();
522         return error;
523 }
524 
525 /**
526  * hibernation_platform_enter - Power off the system using the platform driver.
527  */
528 int hibernation_platform_enter(void)
529 {
530         int error;
531 
532         if (!hibernation_ops)
533                 return -ENOSYS;
534 
535         /*
536          * We have cancelled the power transition by running
537          * hibernation_ops->finish() before saving the image, so we should let
538          * the firmware know that we're going to enter the sleep state after all
539          */
540         error = hibernation_ops->begin();
541         if (error)
542                 goto Close;
543 
544         entering_platform_hibernation = true;
545         suspend_console();
546         error = dpm_suspend_start(PMSG_HIBERNATE);
547         if (error) {
548                 if (hibernation_ops->recover)
549                         hibernation_ops->recover();
550                 goto Resume_devices;
551         }
552 
553         error = dpm_suspend_end(PMSG_HIBERNATE);
554         if (error)
555                 goto Resume_devices;
556 
557         error = hibernation_ops->prepare();
558         if (error)
559                 goto Platform_finish;
560 
561         error = disable_nonboot_cpus();
562         if (error)
563                 goto Enable_cpus;
564 
565         local_irq_disable();
566         syscore_suspend();
567         if (pm_wakeup_pending()) {
568                 error = -EAGAIN;
569                 goto Power_up;
570         }
571 
572         hibernation_ops->enter();
573         /* We should never get here */
574         while (1);
575 
576  Power_up:
577         syscore_resume();
578         local_irq_enable();
579 
580  Enable_cpus:
581         enable_nonboot_cpus();
582 
583  Platform_finish:
584         hibernation_ops->finish();
585 
586         dpm_resume_start(PMSG_RESTORE);
587 
588  Resume_devices:
589         entering_platform_hibernation = false;
590         dpm_resume_end(PMSG_RESTORE);
591         resume_console();
592 
593  Close:
594         hibernation_ops->end();
595 
596         return error;
597 }
598 
599 /**
600  * power_down - Shut the machine down for hibernation.
601  *
602  * Use the platform driver, if configured, to put the system into the sleep
603  * state corresponding to hibernation, or try to power it off or reboot,
604  * depending on the value of hibernation_mode.
605  */
606 static void power_down(void)
607 {
608 #ifdef CONFIG_SUSPEND
609         int error;
610 
611         if (hibernation_mode == HIBERNATION_SUSPEND) {
612                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
613                 if (error) {
614                         hibernation_mode = hibernation_ops ?
615                                                 HIBERNATION_PLATFORM :
616                                                 HIBERNATION_SHUTDOWN;
617                 } else {
618                         /* Restore swap signature. */
619                         error = swsusp_unmark();
620                         if (error)
621                                 pr_err("Swap will be unusable! Try swapon -a.\n");
622 
623                         return;
624                 }
625         }
626 #endif
627 
628         switch (hibernation_mode) {
629         case HIBERNATION_REBOOT:
630                 kernel_restart(NULL);
631                 break;
632         case HIBERNATION_PLATFORM:
633                 hibernation_platform_enter();
634         case HIBERNATION_SHUTDOWN:
635                 if (pm_power_off)
636                         kernel_power_off();
637                 break;
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         pr_crit("Power down manually\n");
645         while (1)
646                 cpu_relax();
647 }
648 
649 static int load_image_and_restore(void)
650 {
651         int error;
652         unsigned int flags;
653 
654         pm_pr_dbg("Loading hibernation image.\n");
655 
656         lock_device_hotplug();
657         error = create_basic_memory_bitmaps();
658         if (error)
659                 goto Unlock;
660 
661         error = swsusp_read(&flags);
662         swsusp_close(FMODE_READ);
663         if (!error)
664                 hibernation_restore(flags & SF_PLATFORM_MODE);
665 
666         pr_err("Failed to load hibernation image, recovering.\n");
667         swsusp_free();
668         free_basic_memory_bitmaps();
669  Unlock:
670         unlock_device_hotplug();
671 
672         return error;
673 }
674 
675 /**
676  * hibernate - Carry out system hibernation, including saving the image.
677  */
678 int hibernate(void)
679 {
680         int error, nr_calls = 0;
681         bool snapshot_test = false;
682 
683         if (!hibernation_available()) {
684                 pm_pr_dbg("Hibernation not available.\n");
685                 return -EPERM;
686         }
687 
688         lock_system_sleep();
689         /* The snapshot device should not be opened while we're running */
690         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
691                 error = -EBUSY;
692                 goto Unlock;
693         }
694 
695         pr_info("hibernation entry\n");
696         pm_prepare_console();
697         error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls);
698         if (error) {
699                 nr_calls--;
700                 goto Exit;
701         }
702 
703         pr_info("Syncing filesystems ... \n");
704         sys_sync();
705         pr_info("done.\n");
706 
707         error = freeze_processes();
708         if (error)
709                 goto Exit;
710 
711         lock_device_hotplug();
712         /* Allocate memory management structures */
713         error = create_basic_memory_bitmaps();
714         if (error)
715                 goto Thaw;
716 
717         error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
718         if (error || freezer_test_done)
719                 goto Free_bitmaps;
720 
721         if (in_suspend) {
722                 unsigned int flags = 0;
723 
724                 if (hibernation_mode == HIBERNATION_PLATFORM)
725                         flags |= SF_PLATFORM_MODE;
726                 if (nocompress)
727                         flags |= SF_NOCOMPRESS_MODE;
728                 else
729                         flags |= SF_CRC32_MODE;
730 
731                 pm_pr_dbg("Writing image.\n");
732                 error = swsusp_write(flags);
733                 swsusp_free();
734                 if (!error) {
735                         if (hibernation_mode == HIBERNATION_TEST_RESUME)
736                                 snapshot_test = true;
737                         else
738                                 power_down();
739                 }
740                 in_suspend = 0;
741                 pm_restore_gfp_mask();
742         } else {
743                 pm_pr_dbg("Image restored successfully.\n");
744         }
745 
746  Free_bitmaps:
747         free_basic_memory_bitmaps();
748  Thaw:
749         unlock_device_hotplug();
750         if (snapshot_test) {
751                 pm_pr_dbg("Checking hibernation image\n");
752                 error = swsusp_check();
753                 if (!error)
754                         error = load_image_and_restore();
755         }
756         thaw_processes();
757 
758         /* Don't bother checking whether freezer_test_done is true */
759         freezer_test_done = false;
760  Exit:
761         __pm_notifier_call_chain(PM_POST_HIBERNATION, nr_calls, NULL);
762         pm_restore_console();
763         atomic_inc(&snapshot_device_available);
764  Unlock:
765         unlock_system_sleep();
766         pr_info("hibernation exit\n");
767 
768         return error;
769 }
770 
771 
772 /**
773  * software_resume - Resume from a saved hibernation image.
774  *
775  * This routine is called as a late initcall, when all devices have been
776  * discovered and initialized already.
777  *
778  * The image reading code is called to see if there is a hibernation image
779  * available for reading.  If that is the case, devices are quiesced and the
780  * contents of memory is restored from the saved image.
781  *
782  * If this is successful, control reappears in the restored target kernel in
783  * hibernation_snapshot() which returns to hibernate().  Otherwise, the routine
784  * attempts to recover gracefully and make the kernel return to the normal mode
785  * of operation.
786  */
787 static int software_resume(void)
788 {
789         int error, nr_calls = 0;
790 
791         /*
792          * If the user said "noresume".. bail out early.
793          */
794         if (noresume || !hibernation_available())
795                 return 0;
796 
797         /*
798          * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
799          * is configured into the kernel. Since the regular hibernate
800          * trigger path is via sysfs which takes a buffer mutex before
801          * calling hibernate functions (which take pm_mutex) this can
802          * cause lockdep to complain about a possible ABBA deadlock
803          * which cannot happen since we're in the boot code here and
804          * sysfs can't be invoked yet. Therefore, we use a subclass
805          * here to avoid lockdep complaining.
806          */
807         mutex_lock_nested(&pm_mutex, SINGLE_DEPTH_NESTING);
808 
809         if (swsusp_resume_device)
810                 goto Check_image;
811 
812         if (!strlen(resume_file)) {
813                 error = -ENOENT;
814                 goto Unlock;
815         }
816 
817         pm_pr_dbg("Checking hibernation image partition %s\n", resume_file);
818 
819         if (resume_delay) {
820                 pr_info("Waiting %dsec before reading resume device ...\n",
821                         resume_delay);
822                 ssleep(resume_delay);
823         }
824 
825         /* Check if the device is there */
826         swsusp_resume_device = name_to_dev_t(resume_file);
827 
828         /*
829          * name_to_dev_t is ineffective to verify parition if resume_file is in
830          * integer format. (e.g. major:minor)
831          */
832         if (isdigit(resume_file[0]) && resume_wait) {
833                 int partno;
834                 while (!get_gendisk(swsusp_resume_device, &partno))
835                         msleep(10);
836         }
837 
838         if (!swsusp_resume_device) {
839                 /*
840                  * Some device discovery might still be in progress; we need
841                  * to wait for this to finish.
842                  */
843                 wait_for_device_probe();
844 
845                 if (resume_wait) {
846                         while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
847                                 msleep(10);
848                         async_synchronize_full();
849                 }
850 
851                 swsusp_resume_device = name_to_dev_t(resume_file);
852                 if (!swsusp_resume_device) {
853                         error = -ENODEV;
854                         goto Unlock;
855                 }
856         }
857 
858  Check_image:
859         pm_pr_dbg("Hibernation image partition %d:%d present\n",
860                 MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
861 
862         pm_pr_dbg("Looking for hibernation image.\n");
863         error = swsusp_check();
864         if (error)
865                 goto Unlock;
866 
867         /* The snapshot device should not be opened while we're running */
868         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
869                 error = -EBUSY;
870                 swsusp_close(FMODE_READ);
871                 goto Unlock;
872         }
873 
874         pr_info("resume from hibernation\n");
875         pm_prepare_console();
876         error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls);
877         if (error) {
878                 nr_calls--;
879                 goto Close_Finish;
880         }
881 
882         pm_pr_dbg("Preparing processes for restore.\n");
883         error = freeze_processes();
884         if (error)
885                 goto Close_Finish;
886         error = load_image_and_restore();
887         thaw_processes();
888  Finish:
889         __pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);
890         pm_restore_console();
891         pr_info("resume from hibernation failed (%d)\n", error);
892         atomic_inc(&snapshot_device_available);
893         /* For success case, the suspend path will release the lock */
894  Unlock:
895         mutex_unlock(&pm_mutex);
896         pm_pr_dbg("Hibernation image not present or could not be loaded.\n");
897         return error;
898  Close_Finish:
899         swsusp_close(FMODE_READ);
900         goto Finish;
901 }
902 
903 late_initcall_sync(software_resume);
904 
905 
906 static const char * const hibernation_modes[] = {
907         [HIBERNATION_PLATFORM]  = "platform",
908         [HIBERNATION_SHUTDOWN]  = "shutdown",
909         [HIBERNATION_REBOOT]    = "reboot",
910 #ifdef CONFIG_SUSPEND
911         [HIBERNATION_SUSPEND]   = "suspend",
912 #endif
913         [HIBERNATION_TEST_RESUME]       = "test_resume",
914 };
915 
916 /*
917  * /sys/power/disk - Control hibernation mode.
918  *
919  * Hibernation can be handled in several ways.  There are a few different ways
920  * to put the system into the sleep state: using the platform driver (e.g. ACPI
921  * or other hibernation_ops), powering it off or rebooting it (for testing
922  * mostly).
923  *
924  * The sysfs file /sys/power/disk provides an interface for selecting the
925  * hibernation mode to use.  Reading from this file causes the available modes
926  * to be printed.  There are 3 modes that can be supported:
927  *
928  *      'platform'
929  *      'shutdown'
930  *      'reboot'
931  *
932  * If a platform hibernation driver is in use, 'platform' will be supported
933  * and will be used by default.  Otherwise, 'shutdown' will be used by default.
934  * The selected option (i.e. the one corresponding to the current value of
935  * hibernation_mode) is enclosed by a square bracket.
936  *
937  * To select a given hibernation mode it is necessary to write the mode's
938  * string representation (as returned by reading from /sys/power/disk) back
939  * into /sys/power/disk.
940  */
941 
942 static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
943                          char *buf)
944 {
945         int i;
946         char *start = buf;
947 
948         if (!hibernation_available())
949                 return sprintf(buf, "[disabled]\n");
950 
951         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
952                 if (!hibernation_modes[i])
953                         continue;
954                 switch (i) {
955                 case HIBERNATION_SHUTDOWN:
956                 case HIBERNATION_REBOOT:
957 #ifdef CONFIG_SUSPEND
958                 case HIBERNATION_SUSPEND:
959 #endif
960                 case HIBERNATION_TEST_RESUME:
961                         break;
962                 case HIBERNATION_PLATFORM:
963                         if (hibernation_ops)
964                                 break;
965                         /* not a valid mode, continue with loop */
966                         continue;
967                 }
968                 if (i == hibernation_mode)
969                         buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
970                 else
971                         buf += sprintf(buf, "%s ", hibernation_modes[i]);
972         }
973         buf += sprintf(buf, "\n");
974         return buf-start;
975 }
976 
977 static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
978                           const char *buf, size_t n)
979 {
980         int error = 0;
981         int i;
982         int len;
983         char *p;
984         int mode = HIBERNATION_INVALID;
985 
986         if (!hibernation_available())
987                 return -EPERM;
988 
989         p = memchr(buf, '\n', n);
990         len = p ? p - buf : n;
991 
992         lock_system_sleep();
993         for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
994                 if (len == strlen(hibernation_modes[i])
995                     && !strncmp(buf, hibernation_modes[i], len)) {
996                         mode = i;
997                         break;
998                 }
999         }
1000         if (mode != HIBERNATION_INVALID) {
1001                 switch (mode) {
1002                 case HIBERNATION_SHUTDOWN:
1003                 case HIBERNATION_REBOOT:
1004 #ifdef CONFIG_SUSPEND
1005                 case HIBERNATION_SUSPEND:
1006 #endif
1007                 case HIBERNATION_TEST_RESUME:
1008                         hibernation_mode = mode;
1009                         break;
1010                 case HIBERNATION_PLATFORM:
1011                         if (hibernation_ops)
1012                                 hibernation_mode = mode;
1013                         else
1014                                 error = -EINVAL;
1015                 }
1016         } else
1017                 error = -EINVAL;
1018 
1019         if (!error)
1020                 pm_pr_dbg("Hibernation mode set to '%s'\n",
1021                                hibernation_modes[mode]);
1022         unlock_system_sleep();
1023         return error ? error : n;
1024 }
1025 
1026 power_attr(disk);
1027 
1028 static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
1029                            char *buf)
1030 {
1031         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
1032                        MINOR(swsusp_resume_device));
1033 }
1034 
1035 static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
1036                             const char *buf, size_t n)
1037 {
1038         dev_t res;
1039         int len = n;
1040         char *name;
1041 
1042         if (len && buf[len-1] == '\n')
1043                 len--;
1044         name = kstrndup(buf, len, GFP_KERNEL);
1045         if (!name)
1046                 return -ENOMEM;
1047 
1048         res = name_to_dev_t(name);
1049         kfree(name);
1050         if (!res)
1051                 return -EINVAL;
1052 
1053         lock_system_sleep();
1054         swsusp_resume_device = res;
1055         unlock_system_sleep();
1056         pr_info("Starting manual resume from disk\n");
1057         noresume = 0;
1058         software_resume();
1059         return n;
1060 }
1061 
1062 power_attr(resume);
1063 
1064 static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
1065                                char *buf)
1066 {
1067         return sprintf(buf, "%lu\n", image_size);
1068 }
1069 
1070 static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
1071                                 const char *buf, size_t n)
1072 {
1073         unsigned long size;
1074 
1075         if (sscanf(buf, "%lu", &size) == 1) {
1076                 image_size = size;
1077                 return n;
1078         }
1079 
1080         return -EINVAL;
1081 }
1082 
1083 power_attr(image_size);
1084 
1085 static ssize_t reserved_size_show(struct kobject *kobj,
1086                                   struct kobj_attribute *attr, char *buf)
1087 {
1088         return sprintf(buf, "%lu\n", reserved_size);
1089 }
1090 
1091 static ssize_t reserved_size_store(struct kobject *kobj,
1092                                    struct kobj_attribute *attr,
1093                                    const char *buf, size_t n)
1094 {
1095         unsigned long size;
1096 
1097         if (sscanf(buf, "%lu", &size) == 1) {
1098                 reserved_size = size;
1099                 return n;
1100         }
1101 
1102         return -EINVAL;
1103 }
1104 
1105 power_attr(reserved_size);
1106 
1107 static struct attribute * g[] = {
1108         &disk_attr.attr,
1109         &resume_attr.attr,
1110         &image_size_attr.attr,
1111         &reserved_size_attr.attr,
1112         NULL,
1113 };
1114 
1115 
1116 static const struct attribute_group attr_group = {
1117         .attrs = g,
1118 };
1119 
1120 
1121 static int __init pm_disk_init(void)
1122 {
1123         return sysfs_create_group(power_kobj, &attr_group);
1124 }
1125 
1126 core_initcall(pm_disk_init);
1127 
1128 
1129 static int __init resume_setup(char *str)
1130 {
1131         if (noresume)
1132                 return 1;
1133 
1134         strncpy( resume_file, str, 255 );
1135         return 1;
1136 }
1137 
1138 static int __init resume_offset_setup(char *str)
1139 {
1140         unsigned long long offset;
1141 
1142         if (noresume)
1143                 return 1;
1144 
1145         if (sscanf(str, "%llu", &offset) == 1)
1146                 swsusp_resume_block = offset;
1147 
1148         return 1;
1149 }
1150 
1151 static int __init hibernate_setup(char *str)
1152 {
1153         if (!strncmp(str, "noresume", 8)) {
1154                 noresume = 1;
1155         } else if (!strncmp(str, "nocompress", 10)) {
1156                 nocompress = 1;
1157         } else if (!strncmp(str, "no", 2)) {
1158                 noresume = 1;
1159                 nohibernate = 1;
1160         } else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)
1161                    && !strncmp(str, "protect_image", 13)) {
1162                 enable_restore_image_protection();
1163         }
1164         return 1;
1165 }
1166 
1167 static int __init noresume_setup(char *str)
1168 {
1169         noresume = 1;
1170         return 1;
1171 }
1172 
1173 static int __init resumewait_setup(char *str)
1174 {
1175         resume_wait = 1;
1176         return 1;
1177 }
1178 
1179 static int __init resumedelay_setup(char *str)
1180 {
1181         int rc = kstrtouint(str, 0, &resume_delay);
1182 
1183         if (rc)
1184                 return rc;
1185         return 1;
1186 }
1187 
1188 static int __init nohibernate_setup(char *str)
1189 {
1190         noresume = 1;
1191         nohibernate = 1;
1192         return 1;
1193 }
1194 
1195 __setup("noresume", noresume_setup);
1196 __setup("resume_offset=", resume_offset_setup);
1197 __setup("resume=", resume_setup);
1198 __setup("hibernate=", hibernate_setup);
1199 __setup("resumewait", resumewait_setup);
1200 __setup("resumedelay=", resumedelay_setup);
1201 __setup("nohibernate", nohibernate_setup);
1202 

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