xref: /linux/kernel/power/hibernate.c (revision 71fd68e7d234f6b7d8407c8f486764d24f8411f4)
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@suse.cz>
7  * Copyright (c) 2009 Rafael J. Wysocki, Novell Inc.
8  *
9  * This file is released under the GPLv2.
10  */
11 
12 #include <linux/suspend.h>
13 #include <linux/syscalls.h>
14 #include <linux/reboot.h>
15 #include <linux/string.h>
16 #include <linux/device.h>
17 #include <linux/kmod.h>
18 #include <linux/delay.h>
19 #include <linux/fs.h>
20 #include <linux/mount.h>
21 #include <linux/pm.h>
22 #include <linux/console.h>
23 #include <linux/cpu.h>
24 #include <linux/freezer.h>
25 #include <scsi/scsi_scan.h>
26 #include <asm/suspend.h>
27 
28 #include "power.h"
29 
30 
31 static int noresume = 0;
32 static char resume_file[256] = CONFIG_PM_STD_PARTITION;
33 dev_t swsusp_resume_device;
34 sector_t swsusp_resume_block;
35 
36 enum {
37 	HIBERNATION_INVALID,
38 	HIBERNATION_PLATFORM,
39 	HIBERNATION_TEST,
40 	HIBERNATION_TESTPROC,
41 	HIBERNATION_SHUTDOWN,
42 	HIBERNATION_REBOOT,
43 	/* keep last */
44 	__HIBERNATION_AFTER_LAST
45 };
46 #define HIBERNATION_MAX (__HIBERNATION_AFTER_LAST-1)
47 #define HIBERNATION_FIRST (HIBERNATION_INVALID + 1)
48 
49 static int hibernation_mode = HIBERNATION_SHUTDOWN;
50 
51 static struct platform_hibernation_ops *hibernation_ops;
52 
53 /**
54  * hibernation_set_ops - set the global hibernate operations
55  * @ops: the hibernation operations to use in subsequent hibernation transitions
56  */
57 
58 void hibernation_set_ops(struct platform_hibernation_ops *ops)
59 {
60 	if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
61 	    && ops->prepare && ops->finish && ops->enter && ops->pre_restore
62 	    && ops->restore_cleanup)) {
63 		WARN_ON(1);
64 		return;
65 	}
66 	mutex_lock(&pm_mutex);
67 	hibernation_ops = ops;
68 	if (ops)
69 		hibernation_mode = HIBERNATION_PLATFORM;
70 	else if (hibernation_mode == HIBERNATION_PLATFORM)
71 		hibernation_mode = HIBERNATION_SHUTDOWN;
72 
73 	mutex_unlock(&pm_mutex);
74 }
75 
76 static bool entering_platform_hibernation;
77 
78 bool system_entering_hibernation(void)
79 {
80 	return entering_platform_hibernation;
81 }
82 EXPORT_SYMBOL(system_entering_hibernation);
83 
84 #ifdef CONFIG_PM_DEBUG
85 static void hibernation_debug_sleep(void)
86 {
87 	printk(KERN_INFO "hibernation debug: Waiting for 5 seconds.\n");
88 	mdelay(5000);
89 }
90 
91 static int hibernation_testmode(int mode)
92 {
93 	if (hibernation_mode == mode) {
94 		hibernation_debug_sleep();
95 		return 1;
96 	}
97 	return 0;
98 }
99 
100 static int hibernation_test(int level)
101 {
102 	if (pm_test_level == level) {
103 		hibernation_debug_sleep();
104 		return 1;
105 	}
106 	return 0;
107 }
108 #else /* !CONFIG_PM_DEBUG */
109 static int hibernation_testmode(int mode) { return 0; }
110 static int hibernation_test(int level) { return 0; }
111 #endif /* !CONFIG_PM_DEBUG */
112 
113 /**
114  *	platform_begin - tell the platform driver that we're starting
115  *	hibernation
116  */
117 
118 static int platform_begin(int platform_mode)
119 {
120 	return (platform_mode && hibernation_ops) ?
121 		hibernation_ops->begin() : 0;
122 }
123 
124 /**
125  *	platform_end - tell the platform driver that we've entered the
126  *	working state
127  */
128 
129 static void platform_end(int platform_mode)
130 {
131 	if (platform_mode && hibernation_ops)
132 		hibernation_ops->end();
133 }
134 
135 /**
136  *	platform_pre_snapshot - prepare the machine for hibernation using the
137  *	platform driver if so configured and return an error code if it fails
138  */
139 
140 static int platform_pre_snapshot(int platform_mode)
141 {
142 	return (platform_mode && hibernation_ops) ?
143 		hibernation_ops->pre_snapshot() : 0;
144 }
145 
146 /**
147  *	platform_leave - prepare the machine for switching to the normal mode
148  *	of operation using the platform driver (called with interrupts disabled)
149  */
150 
151 static void platform_leave(int platform_mode)
152 {
153 	if (platform_mode && hibernation_ops)
154 		hibernation_ops->leave();
155 }
156 
157 /**
158  *	platform_finish - switch the machine to the normal mode of operation
159  *	using the platform driver (must be called after platform_prepare())
160  */
161 
162 static void platform_finish(int platform_mode)
163 {
164 	if (platform_mode && hibernation_ops)
165 		hibernation_ops->finish();
166 }
167 
168 /**
169  *	platform_pre_restore - prepare the platform for the restoration from a
170  *	hibernation image.  If the restore fails after this function has been
171  *	called, platform_restore_cleanup() must be called.
172  */
173 
174 static int platform_pre_restore(int platform_mode)
175 {
176 	return (platform_mode && hibernation_ops) ?
177 		hibernation_ops->pre_restore() : 0;
178 }
179 
180 /**
181  *	platform_restore_cleanup - switch the platform to the normal mode of
182  *	operation after a failing restore.  If platform_pre_restore() has been
183  *	called before the failing restore, this function must be called too,
184  *	regardless of the result of platform_pre_restore().
185  */
186 
187 static void platform_restore_cleanup(int platform_mode)
188 {
189 	if (platform_mode && hibernation_ops)
190 		hibernation_ops->restore_cleanup();
191 }
192 
193 /**
194  *	platform_recover - recover the platform from a failure to suspend
195  *	devices.
196  */
197 
198 static void platform_recover(int platform_mode)
199 {
200 	if (platform_mode && hibernation_ops && hibernation_ops->recover)
201 		hibernation_ops->recover();
202 }
203 
204 /**
205  *	create_image - freeze devices that need to be frozen with interrupts
206  *	off, create the hibernation image and thaw those devices.  Control
207  *	reappears in this routine after a restore.
208  */
209 
210 static int create_image(int platform_mode)
211 {
212 	int error;
213 
214 	error = arch_prepare_suspend();
215 	if (error)
216 		return error;
217 
218 	/* At this point, dpm_suspend_start() has been called, but *not*
219 	 * dpm_suspend_noirq(). We *must* call dpm_suspend_noirq() now.
220 	 * Otherwise, drivers for some devices (e.g. interrupt controllers)
221 	 * become desynchronized with the actual state of the hardware
222 	 * at resume time, and evil weirdness ensues.
223 	 */
224 	error = dpm_suspend_noirq(PMSG_FREEZE);
225 	if (error) {
226 		printk(KERN_ERR "PM: Some devices failed to power down, "
227 			"aborting hibernation\n");
228 		return error;
229 	}
230 
231 	error = platform_pre_snapshot(platform_mode);
232 	if (error || hibernation_test(TEST_PLATFORM))
233 		goto Platform_finish;
234 
235 	error = disable_nonboot_cpus();
236 	if (error || hibernation_test(TEST_CPUS)
237 	    || hibernation_testmode(HIBERNATION_TEST))
238 		goto Enable_cpus;
239 
240 	local_irq_disable();
241 
242 	error = sysdev_suspend(PMSG_FREEZE);
243 	if (error) {
244 		printk(KERN_ERR "PM: Some system devices failed to power down, "
245 			"aborting hibernation\n");
246 		goto Enable_irqs;
247 	}
248 
249 	if (hibernation_test(TEST_CORE))
250 		goto Power_up;
251 
252 	in_suspend = 1;
253 	save_processor_state();
254 	error = swsusp_arch_suspend();
255 	if (error)
256 		printk(KERN_ERR "PM: Error %d creating hibernation image\n",
257 			error);
258 	/* Restore control flow magically appears here */
259 	restore_processor_state();
260 	if (!in_suspend)
261 		platform_leave(platform_mode);
262 
263  Power_up:
264 	sysdev_resume();
265 	/* NOTE:  dpm_resume_noirq() is just a resume() for devices
266 	 * that suspended with irqs off ... no overall powerup.
267 	 */
268 
269  Enable_irqs:
270 	local_irq_enable();
271 
272  Enable_cpus:
273 	enable_nonboot_cpus();
274 
275  Platform_finish:
276 	platform_finish(platform_mode);
277 
278 	dpm_resume_noirq(in_suspend ?
279 		(error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
280 
281 	return error;
282 }
283 
284 /**
285  *	hibernation_snapshot - quiesce devices and create the hibernation
286  *	snapshot image.
287  *	@platform_mode - if set, use the platform driver, if available, to
288  *			 prepare the platform firmware for the power transition.
289  *
290  *	Must be called with pm_mutex held
291  */
292 
293 int hibernation_snapshot(int platform_mode)
294 {
295 	int error;
296 
297 	error = platform_begin(platform_mode);
298 	if (error)
299 		return error;
300 
301 	/* Preallocate image memory before shutting down devices. */
302 	error = hibernate_preallocate_memory();
303 	if (error)
304 		goto Close;
305 
306 	suspend_console();
307 	error = dpm_suspend_start(PMSG_FREEZE);
308 	if (error)
309 		goto Recover_platform;
310 
311 	if (hibernation_test(TEST_DEVICES))
312 		goto Recover_platform;
313 
314 	error = create_image(platform_mode);
315 	/* Control returns here after successful restore */
316 
317  Resume_devices:
318 	/* We may need to release the preallocated image pages here. */
319 	if (error || !in_suspend)
320 		swsusp_free();
321 
322 	dpm_resume_end(in_suspend ?
323 		(error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
324 	resume_console();
325  Close:
326 	platform_end(platform_mode);
327 	return error;
328 
329  Recover_platform:
330 	platform_recover(platform_mode);
331 	goto Resume_devices;
332 }
333 
334 /**
335  *	resume_target_kernel - prepare devices that need to be suspended with
336  *	interrupts off, restore the contents of highmem that have not been
337  *	restored yet from the image and run the low level code that will restore
338  *	the remaining contents of memory and switch to the just restored target
339  *	kernel.
340  */
341 
342 static int resume_target_kernel(bool platform_mode)
343 {
344 	int error;
345 
346 	error = dpm_suspend_noirq(PMSG_QUIESCE);
347 	if (error) {
348 		printk(KERN_ERR "PM: Some devices failed to power down, "
349 			"aborting resume\n");
350 		return error;
351 	}
352 
353 	error = platform_pre_restore(platform_mode);
354 	if (error)
355 		goto Cleanup;
356 
357 	error = disable_nonboot_cpus();
358 	if (error)
359 		goto Enable_cpus;
360 
361 	local_irq_disable();
362 
363 	error = sysdev_suspend(PMSG_QUIESCE);
364 	if (error)
365 		goto Enable_irqs;
366 
367 	/* We'll ignore saved state, but this gets preempt count (etc) right */
368 	save_processor_state();
369 	error = restore_highmem();
370 	if (!error) {
371 		error = swsusp_arch_resume();
372 		/*
373 		 * The code below is only ever reached in case of a failure.
374 		 * Otherwise execution continues at place where
375 		 * swsusp_arch_suspend() was called
376 		 */
377 		BUG_ON(!error);
378 		/* This call to restore_highmem() undos the previous one */
379 		restore_highmem();
380 	}
381 	/*
382 	 * The only reason why swsusp_arch_resume() can fail is memory being
383 	 * very tight, so we have to free it as soon as we can to avoid
384 	 * subsequent failures
385 	 */
386 	swsusp_free();
387 	restore_processor_state();
388 	touch_softlockup_watchdog();
389 
390 	sysdev_resume();
391 
392  Enable_irqs:
393 	local_irq_enable();
394 
395  Enable_cpus:
396 	enable_nonboot_cpus();
397 
398  Cleanup:
399 	platform_restore_cleanup(platform_mode);
400 
401 	dpm_resume_noirq(PMSG_RECOVER);
402 
403 	return error;
404 }
405 
406 /**
407  *	hibernation_restore - quiesce devices and restore the hibernation
408  *	snapshot image.  If successful, control returns in hibernation_snaphot()
409  *	@platform_mode - if set, use the platform driver, if available, to
410  *			 prepare the platform firmware for the transition.
411  *
412  *	Must be called with pm_mutex held
413  */
414 
415 int hibernation_restore(int platform_mode)
416 {
417 	int error;
418 
419 	pm_prepare_console();
420 	suspend_console();
421 	error = dpm_suspend_start(PMSG_QUIESCE);
422 	if (!error) {
423 		error = resume_target_kernel(platform_mode);
424 		dpm_resume_end(PMSG_RECOVER);
425 	}
426 	resume_console();
427 	pm_restore_console();
428 	return error;
429 }
430 
431 /**
432  *	hibernation_platform_enter - enter the hibernation state using the
433  *	platform driver (if available)
434  */
435 
436 int hibernation_platform_enter(void)
437 {
438 	int error;
439 
440 	if (!hibernation_ops)
441 		return -ENOSYS;
442 
443 	/*
444 	 * We have cancelled the power transition by running
445 	 * hibernation_ops->finish() before saving the image, so we should let
446 	 * the firmware know that we're going to enter the sleep state after all
447 	 */
448 	error = hibernation_ops->begin();
449 	if (error)
450 		goto Close;
451 
452 	entering_platform_hibernation = true;
453 	suspend_console();
454 	error = dpm_suspend_start(PMSG_HIBERNATE);
455 	if (error) {
456 		if (hibernation_ops->recover)
457 			hibernation_ops->recover();
458 		goto Resume_devices;
459 	}
460 
461 	error = dpm_suspend_noirq(PMSG_HIBERNATE);
462 	if (error)
463 		goto Resume_devices;
464 
465 	error = hibernation_ops->prepare();
466 	if (error)
467 		goto Platform_finish;
468 
469 	error = disable_nonboot_cpus();
470 	if (error)
471 		goto Platform_finish;
472 
473 	local_irq_disable();
474 	sysdev_suspend(PMSG_HIBERNATE);
475 	hibernation_ops->enter();
476 	/* We should never get here */
477 	while (1);
478 
479 	/*
480 	 * We don't need to reenable the nonboot CPUs or resume consoles, since
481 	 * the system is going to be halted anyway.
482 	 */
483  Platform_finish:
484 	hibernation_ops->finish();
485 
486 	dpm_suspend_noirq(PMSG_RESTORE);
487 
488  Resume_devices:
489 	entering_platform_hibernation = false;
490 	dpm_resume_end(PMSG_RESTORE);
491 	resume_console();
492 
493  Close:
494 	hibernation_ops->end();
495 
496 	return error;
497 }
498 
499 /**
500  *	power_down - Shut the machine down for hibernation.
501  *
502  *	Use the platform driver, if configured so; otherwise try
503  *	to power off or reboot.
504  */
505 
506 static void power_down(void)
507 {
508 	switch (hibernation_mode) {
509 	case HIBERNATION_TEST:
510 	case HIBERNATION_TESTPROC:
511 		break;
512 	case HIBERNATION_REBOOT:
513 		kernel_restart(NULL);
514 		break;
515 	case HIBERNATION_PLATFORM:
516 		hibernation_platform_enter();
517 	case HIBERNATION_SHUTDOWN:
518 		kernel_power_off();
519 		break;
520 	}
521 	kernel_halt();
522 	/*
523 	 * Valid image is on the disk, if we continue we risk serious data
524 	 * corruption after resume.
525 	 */
526 	printk(KERN_CRIT "PM: Please power down manually\n");
527 	while(1);
528 }
529 
530 static int prepare_processes(void)
531 {
532 	int error = 0;
533 
534 	if (freeze_processes()) {
535 		error = -EBUSY;
536 		thaw_processes();
537 	}
538 	return error;
539 }
540 
541 /**
542  *	hibernate - The granpappy of the built-in hibernation management
543  */
544 
545 int hibernate(void)
546 {
547 	int error;
548 
549 	mutex_lock(&pm_mutex);
550 	/* The snapshot device should not be opened while we're running */
551 	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
552 		error = -EBUSY;
553 		goto Unlock;
554 	}
555 
556 	pm_prepare_console();
557 	error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
558 	if (error)
559 		goto Exit;
560 
561 	error = usermodehelper_disable();
562 	if (error)
563 		goto Exit;
564 
565 	/* Allocate memory management structures */
566 	error = create_basic_memory_bitmaps();
567 	if (error)
568 		goto Exit;
569 
570 	printk(KERN_INFO "PM: Syncing filesystems ... ");
571 	sys_sync();
572 	printk("done.\n");
573 
574 	error = prepare_processes();
575 	if (error)
576 		goto Finish;
577 
578 	if (hibernation_test(TEST_FREEZER))
579 		goto Thaw;
580 
581 	if (hibernation_testmode(HIBERNATION_TESTPROC))
582 		goto Thaw;
583 
584 	error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
585 	if (error)
586 		goto Thaw;
587 
588 	if (in_suspend) {
589 		unsigned int flags = 0;
590 
591 		if (hibernation_mode == HIBERNATION_PLATFORM)
592 			flags |= SF_PLATFORM_MODE;
593 		pr_debug("PM: writing image.\n");
594 		error = swsusp_write(flags);
595 		swsusp_free();
596 		if (!error)
597 			power_down();
598 	} else {
599 		pr_debug("PM: Image restored successfully.\n");
600 	}
601 
602  Thaw:
603 	thaw_processes();
604  Finish:
605 	free_basic_memory_bitmaps();
606 	usermodehelper_enable();
607  Exit:
608 	pm_notifier_call_chain(PM_POST_HIBERNATION);
609 	pm_restore_console();
610 	atomic_inc(&snapshot_device_available);
611  Unlock:
612 	mutex_unlock(&pm_mutex);
613 	return error;
614 }
615 
616 
617 /**
618  *	software_resume - Resume from a saved image.
619  *
620  *	Called as a late_initcall (so all devices are discovered and
621  *	initialized), we call swsusp to see if we have a saved image or not.
622  *	If so, we quiesce devices, the restore the saved image. We will
623  *	return above (in hibernate() ) if everything goes well.
624  *	Otherwise, we fail gracefully and return to the normally
625  *	scheduled program.
626  *
627  */
628 
629 static int software_resume(void)
630 {
631 	int error;
632 	unsigned int flags;
633 
634 	/*
635 	 * If the user said "noresume".. bail out early.
636 	 */
637 	if (noresume)
638 		return 0;
639 
640 	/*
641 	 * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
642 	 * is configured into the kernel. Since the regular hibernate
643 	 * trigger path is via sysfs which takes a buffer mutex before
644 	 * calling hibernate functions (which take pm_mutex) this can
645 	 * cause lockdep to complain about a possible ABBA deadlock
646 	 * which cannot happen since we're in the boot code here and
647 	 * sysfs can't be invoked yet. Therefore, we use a subclass
648 	 * here to avoid lockdep complaining.
649 	 */
650 	mutex_lock_nested(&pm_mutex, SINGLE_DEPTH_NESTING);
651 
652 	if (swsusp_resume_device)
653 		goto Check_image;
654 
655 	if (!strlen(resume_file)) {
656 		error = -ENOENT;
657 		goto Unlock;
658 	}
659 
660 	pr_debug("PM: Checking image partition %s\n", resume_file);
661 
662 	/* Check if the device is there */
663 	swsusp_resume_device = name_to_dev_t(resume_file);
664 	if (!swsusp_resume_device) {
665 		/*
666 		 * Some device discovery might still be in progress; we need
667 		 * to wait for this to finish.
668 		 */
669 		wait_for_device_probe();
670 		/*
671 		 * We can't depend on SCSI devices being available after loading
672 		 * one of their modules until scsi_complete_async_scans() is
673 		 * called and the resume device usually is a SCSI one.
674 		 */
675 		scsi_complete_async_scans();
676 
677 		swsusp_resume_device = name_to_dev_t(resume_file);
678 		if (!swsusp_resume_device) {
679 			error = -ENODEV;
680 			goto Unlock;
681 		}
682 	}
683 
684  Check_image:
685 	pr_debug("PM: Resume from partition %d:%d\n",
686 		MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
687 
688 	pr_debug("PM: Checking hibernation image.\n");
689 	error = swsusp_check();
690 	if (error)
691 		goto Unlock;
692 
693 	/* The snapshot device should not be opened while we're running */
694 	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
695 		error = -EBUSY;
696 		goto Unlock;
697 	}
698 
699 	pm_prepare_console();
700 	error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
701 	if (error)
702 		goto Finish;
703 
704 	error = usermodehelper_disable();
705 	if (error)
706 		goto Finish;
707 
708 	error = create_basic_memory_bitmaps();
709 	if (error)
710 		goto Finish;
711 
712 	pr_debug("PM: Preparing processes for restore.\n");
713 	error = prepare_processes();
714 	if (error) {
715 		swsusp_close(FMODE_READ);
716 		goto Done;
717 	}
718 
719 	pr_debug("PM: Reading hibernation image.\n");
720 
721 	error = swsusp_read(&flags);
722 	if (!error)
723 		hibernation_restore(flags & SF_PLATFORM_MODE);
724 
725 	printk(KERN_ERR "PM: Restore failed, recovering.\n");
726 	swsusp_free();
727 	thaw_processes();
728  Done:
729 	free_basic_memory_bitmaps();
730 	usermodehelper_enable();
731  Finish:
732 	pm_notifier_call_chain(PM_POST_RESTORE);
733 	pm_restore_console();
734 	atomic_inc(&snapshot_device_available);
735 	/* For success case, the suspend path will release the lock */
736  Unlock:
737 	mutex_unlock(&pm_mutex);
738 	pr_debug("PM: Resume from disk failed.\n");
739 	return error;
740 }
741 
742 late_initcall(software_resume);
743 
744 
745 static const char * const hibernation_modes[] = {
746 	[HIBERNATION_PLATFORM]	= "platform",
747 	[HIBERNATION_SHUTDOWN]	= "shutdown",
748 	[HIBERNATION_REBOOT]	= "reboot",
749 	[HIBERNATION_TEST]	= "test",
750 	[HIBERNATION_TESTPROC]	= "testproc",
751 };
752 
753 /**
754  *	disk - Control hibernation mode
755  *
756  *	Suspend-to-disk can be handled in several ways. We have a few options
757  *	for putting the system to sleep - using the platform driver (e.g. ACPI
758  *	or other hibernation_ops), powering off the system or rebooting the
759  *	system (for testing) as well as the two test modes.
760  *
761  *	The system can support 'platform', and that is known a priori (and
762  *	encoded by the presence of hibernation_ops). However, the user may
763  *	choose 'shutdown' or 'reboot' as alternatives, as well as one fo the
764  *	test modes, 'test' or 'testproc'.
765  *
766  *	show() will display what the mode is currently set to.
767  *	store() will accept one of
768  *
769  *	'platform'
770  *	'shutdown'
771  *	'reboot'
772  *	'test'
773  *	'testproc'
774  *
775  *	It will only change to 'platform' if the system
776  *	supports it (as determined by having hibernation_ops).
777  */
778 
779 static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
780 			 char *buf)
781 {
782 	int i;
783 	char *start = buf;
784 
785 	for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
786 		if (!hibernation_modes[i])
787 			continue;
788 		switch (i) {
789 		case HIBERNATION_SHUTDOWN:
790 		case HIBERNATION_REBOOT:
791 		case HIBERNATION_TEST:
792 		case HIBERNATION_TESTPROC:
793 			break;
794 		case HIBERNATION_PLATFORM:
795 			if (hibernation_ops)
796 				break;
797 			/* not a valid mode, continue with loop */
798 			continue;
799 		}
800 		if (i == hibernation_mode)
801 			buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
802 		else
803 			buf += sprintf(buf, "%s ", hibernation_modes[i]);
804 	}
805 	buf += sprintf(buf, "\n");
806 	return buf-start;
807 }
808 
809 
810 static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
811 			  const char *buf, size_t n)
812 {
813 	int error = 0;
814 	int i;
815 	int len;
816 	char *p;
817 	int mode = HIBERNATION_INVALID;
818 
819 	p = memchr(buf, '\n', n);
820 	len = p ? p - buf : n;
821 
822 	mutex_lock(&pm_mutex);
823 	for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
824 		if (len == strlen(hibernation_modes[i])
825 		    && !strncmp(buf, hibernation_modes[i], len)) {
826 			mode = i;
827 			break;
828 		}
829 	}
830 	if (mode != HIBERNATION_INVALID) {
831 		switch (mode) {
832 		case HIBERNATION_SHUTDOWN:
833 		case HIBERNATION_REBOOT:
834 		case HIBERNATION_TEST:
835 		case HIBERNATION_TESTPROC:
836 			hibernation_mode = mode;
837 			break;
838 		case HIBERNATION_PLATFORM:
839 			if (hibernation_ops)
840 				hibernation_mode = mode;
841 			else
842 				error = -EINVAL;
843 		}
844 	} else
845 		error = -EINVAL;
846 
847 	if (!error)
848 		pr_debug("PM: Hibernation mode set to '%s'\n",
849 			 hibernation_modes[mode]);
850 	mutex_unlock(&pm_mutex);
851 	return error ? error : n;
852 }
853 
854 power_attr(disk);
855 
856 static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
857 			   char *buf)
858 {
859 	return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
860 		       MINOR(swsusp_resume_device));
861 }
862 
863 static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
864 			    const char *buf, size_t n)
865 {
866 	unsigned int maj, min;
867 	dev_t res;
868 	int ret = -EINVAL;
869 
870 	if (sscanf(buf, "%u:%u", &maj, &min) != 2)
871 		goto out;
872 
873 	res = MKDEV(maj,min);
874 	if (maj != MAJOR(res) || min != MINOR(res))
875 		goto out;
876 
877 	mutex_lock(&pm_mutex);
878 	swsusp_resume_device = res;
879 	mutex_unlock(&pm_mutex);
880 	printk(KERN_INFO "PM: Starting manual resume from disk\n");
881 	noresume = 0;
882 	software_resume();
883 	ret = n;
884  out:
885 	return ret;
886 }
887 
888 power_attr(resume);
889 
890 static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
891 			       char *buf)
892 {
893 	return sprintf(buf, "%lu\n", image_size);
894 }
895 
896 static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
897 				const char *buf, size_t n)
898 {
899 	unsigned long size;
900 
901 	if (sscanf(buf, "%lu", &size) == 1) {
902 		image_size = size;
903 		return n;
904 	}
905 
906 	return -EINVAL;
907 }
908 
909 power_attr(image_size);
910 
911 static struct attribute * g[] = {
912 	&disk_attr.attr,
913 	&resume_attr.attr,
914 	&image_size_attr.attr,
915 	NULL,
916 };
917 
918 
919 static struct attribute_group attr_group = {
920 	.attrs = g,
921 };
922 
923 
924 static int __init pm_disk_init(void)
925 {
926 	return sysfs_create_group(power_kobj, &attr_group);
927 }
928 
929 core_initcall(pm_disk_init);
930 
931 
932 static int __init resume_setup(char *str)
933 {
934 	if (noresume)
935 		return 1;
936 
937 	strncpy( resume_file, str, 255 );
938 	return 1;
939 }
940 
941 static int __init resume_offset_setup(char *str)
942 {
943 	unsigned long long offset;
944 
945 	if (noresume)
946 		return 1;
947 
948 	if (sscanf(str, "%llu", &offset) == 1)
949 		swsusp_resume_block = offset;
950 
951 	return 1;
952 }
953 
954 static int __init noresume_setup(char *str)
955 {
956 	noresume = 1;
957 	return 1;
958 }
959 
960 __setup("noresume", noresume_setup);
961 __setup("resume_offset=", resume_offset_setup);
962 __setup("resume=", resume_setup);
963