1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * kernel/power/main.c - PM subsystem core functionality.
4 *
5 * Copyright (c) 2003 Patrick Mochel
6 * Copyright (c) 2003 Open Source Development Lab
7 */
8
9#include <linux/acpi.h>
10#include <linux/export.h>
11#include <linux/kobject.h>
12#include <linux/string.h>
13#include <linux/pm-trace.h>
14#include <linux/workqueue.h>
15#include <linux/debugfs.h>
16#include <linux/seq_file.h>
17#include <linux/suspend.h>
18#include <linux/syscalls.h>
19#include <linux/pm_runtime.h>
20
21#include "power.h"
22
23#ifdef CONFIG_PM_SLEEP
24/*
25 * The following functions are used by the suspend/hibernate code to temporarily
26 * change gfp_allowed_mask in order to avoid using I/O during memory allocations
27 * while devices are suspended. To avoid races with the suspend/hibernate code,
28 * they should always be called with system_transition_mutex held
29 * (gfp_allowed_mask also should only be modified with system_transition_mutex
30 * held, unless the suspend/hibernate code is guaranteed not to run in parallel
31 * with that modification).
32 */
33static gfp_t saved_gfp_mask;
34
35void pm_restore_gfp_mask(void)
36{
37 WARN_ON(!mutex_is_locked(&system_transition_mutex));
38 if (saved_gfp_mask) {
39 gfp_allowed_mask = saved_gfp_mask;
40 saved_gfp_mask = 0;
41 }
42}
43
44void pm_restrict_gfp_mask(void)
45{
46 WARN_ON(!mutex_is_locked(&system_transition_mutex));
47 WARN_ON(saved_gfp_mask);
48 saved_gfp_mask = gfp_allowed_mask;
49 gfp_allowed_mask &= ~(__GFP_IO | __GFP_FS);
50}
51
52unsigned int lock_system_sleep(void)
53{
54 unsigned int flags = current->flags;
55 current->flags |= PF_NOFREEZE;
56 mutex_lock(&system_transition_mutex);
57 return flags;
58}
59EXPORT_SYMBOL_GPL(lock_system_sleep);
60
61void unlock_system_sleep(unsigned int flags)
62{
63 /*
64 * Don't use freezer_count() because we don't want the call to
65 * try_to_freeze() here.
66 *
67 * Reason:
68 * Fundamentally, we just don't need it, because freezing condition
69 * doesn't come into effect until we release the
70 * system_transition_mutex lock, since the freezer always works with
71 * system_transition_mutex held.
72 *
73 * More importantly, in the case of hibernation,
74 * unlock_system_sleep() gets called in snapshot_read() and
75 * snapshot_write() when the freezing condition is still in effect.
76 * Which means, if we use try_to_freeze() here, it would make them
77 * enter the refrigerator, thus causing hibernation to lockup.
78 */
79 if (!(flags & PF_NOFREEZE))
80 current->flags &= ~PF_NOFREEZE;
81 mutex_unlock(lock: &system_transition_mutex);
82}
83EXPORT_SYMBOL_GPL(unlock_system_sleep);
84
85void ksys_sync_helper(void)
86{
87 ktime_t start;
88 long elapsed_msecs;
89
90 start = ktime_get();
91 ksys_sync();
92 elapsed_msecs = ktime_to_ms(ktime_sub(ktime_get(), start));
93 pr_info("Filesystems sync: %ld.%03ld seconds\n",
94 elapsed_msecs / MSEC_PER_SEC, elapsed_msecs % MSEC_PER_SEC);
95}
96EXPORT_SYMBOL_GPL(ksys_sync_helper);
97
98/* Routines for PM-transition notifications */
99
100static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
101
102int register_pm_notifier(struct notifier_block *nb)
103{
104 return blocking_notifier_chain_register(nh: &pm_chain_head, nb);
105}
106EXPORT_SYMBOL_GPL(register_pm_notifier);
107
108int unregister_pm_notifier(struct notifier_block *nb)
109{
110 return blocking_notifier_chain_unregister(nh: &pm_chain_head, nb);
111}
112EXPORT_SYMBOL_GPL(unregister_pm_notifier);
113
114void pm_report_hw_sleep_time(u64 t)
115{
116 suspend_stats.last_hw_sleep = t;
117 suspend_stats.total_hw_sleep += t;
118}
119EXPORT_SYMBOL_GPL(pm_report_hw_sleep_time);
120
121void pm_report_max_hw_sleep(u64 t)
122{
123 suspend_stats.max_hw_sleep = t;
124}
125EXPORT_SYMBOL_GPL(pm_report_max_hw_sleep);
126
127int pm_notifier_call_chain_robust(unsigned long val_up, unsigned long val_down)
128{
129 int ret;
130
131 ret = blocking_notifier_call_chain_robust(nh: &pm_chain_head, val_up, val_down, NULL);
132
133 return notifier_to_errno(ret);
134}
135
136int pm_notifier_call_chain(unsigned long val)
137{
138 return blocking_notifier_call_chain(nh: &pm_chain_head, val, NULL);
139}
140
141/* If set, devices may be suspended and resumed asynchronously. */
142int pm_async_enabled = 1;
143
144static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr,
145 char *buf)
146{
147 return sprintf(buf, fmt: "%d\n", pm_async_enabled);
148}
149
150static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr,
151 const char *buf, size_t n)
152{
153 unsigned long val;
154
155 if (kstrtoul(s: buf, base: 10, res: &val))
156 return -EINVAL;
157
158 if (val > 1)
159 return -EINVAL;
160
161 pm_async_enabled = val;
162 return n;
163}
164
165power_attr(pm_async);
166
167#ifdef CONFIG_SUSPEND
168static ssize_t mem_sleep_show(struct kobject *kobj, struct kobj_attribute *attr,
169 char *buf)
170{
171 char *s = buf;
172 suspend_state_t i;
173
174 for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++) {
175 if (i >= PM_SUSPEND_MEM && cxl_mem_active())
176 continue;
177 if (mem_sleep_states[i]) {
178 const char *label = mem_sleep_states[i];
179
180 if (mem_sleep_current == i)
181 s += sprintf(buf: s, fmt: "[%s] ", label);
182 else
183 s += sprintf(buf: s, fmt: "%s ", label);
184 }
185 }
186
187 /* Convert the last space to a newline if needed. */
188 if (s != buf)
189 *(s-1) = '\n';
190
191 return (s - buf);
192}
193
194static suspend_state_t decode_suspend_state(const char *buf, size_t n)
195{
196 suspend_state_t state;
197 char *p;
198 int len;
199
200 p = memchr(p: buf, c: '\n', size: n);
201 len = p ? p - buf : n;
202
203 for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) {
204 const char *label = mem_sleep_states[state];
205
206 if (label && len == strlen(label) && !strncmp(buf, label, len))
207 return state;
208 }
209
210 return PM_SUSPEND_ON;
211}
212
213static ssize_t mem_sleep_store(struct kobject *kobj, struct kobj_attribute *attr,
214 const char *buf, size_t n)
215{
216 suspend_state_t state;
217 int error;
218
219 error = pm_autosleep_lock();
220 if (error)
221 return error;
222
223 if (pm_autosleep_state() > PM_SUSPEND_ON) {
224 error = -EBUSY;
225 goto out;
226 }
227
228 state = decode_suspend_state(buf, n);
229 if (state < PM_SUSPEND_MAX && state > PM_SUSPEND_ON)
230 mem_sleep_current = state;
231 else
232 error = -EINVAL;
233
234 out:
235 pm_autosleep_unlock();
236 return error ? error : n;
237}
238
239power_attr(mem_sleep);
240
241/*
242 * sync_on_suspend: invoke ksys_sync_helper() before suspend.
243 *
244 * show() returns whether ksys_sync_helper() is invoked before suspend.
245 * store() accepts 0 or 1. 0 disables ksys_sync_helper() and 1 enables it.
246 */
247bool sync_on_suspend_enabled = !IS_ENABLED(CONFIG_SUSPEND_SKIP_SYNC);
248
249static ssize_t sync_on_suspend_show(struct kobject *kobj,
250 struct kobj_attribute *attr, char *buf)
251{
252 return sprintf(buf, fmt: "%d\n", sync_on_suspend_enabled);
253}
254
255static ssize_t sync_on_suspend_store(struct kobject *kobj,
256 struct kobj_attribute *attr,
257 const char *buf, size_t n)
258{
259 unsigned long val;
260
261 if (kstrtoul(s: buf, base: 10, res: &val))
262 return -EINVAL;
263
264 if (val > 1)
265 return -EINVAL;
266
267 sync_on_suspend_enabled = !!val;
268 return n;
269}
270
271power_attr(sync_on_suspend);
272#endif /* CONFIG_SUSPEND */
273
274#ifdef CONFIG_PM_SLEEP_DEBUG
275int pm_test_level = TEST_NONE;
276
277static const char * const pm_tests[__TEST_AFTER_LAST] = {
278 [TEST_NONE] = "none",
279 [TEST_CORE] = "core",
280 [TEST_CPUS] = "processors",
281 [TEST_PLATFORM] = "platform",
282 [TEST_DEVICES] = "devices",
283 [TEST_FREEZER] = "freezer",
284};
285
286static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
287 char *buf)
288{
289 char *s = buf;
290 int level;
291
292 for (level = TEST_FIRST; level <= TEST_MAX; level++)
293 if (pm_tests[level]) {
294 if (level == pm_test_level)
295 s += sprintf(buf: s, fmt: "[%s] ", pm_tests[level]);
296 else
297 s += sprintf(buf: s, fmt: "%s ", pm_tests[level]);
298 }
299
300 if (s != buf)
301 /* convert the last space to a newline */
302 *(s-1) = '\n';
303
304 return (s - buf);
305}
306
307static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
308 const char *buf, size_t n)
309{
310 unsigned int sleep_flags;
311 const char * const *s;
312 int error = -EINVAL;
313 int level;
314 char *p;
315 int len;
316
317 p = memchr(p: buf, c: '\n', size: n);
318 len = p ? p - buf : n;
319
320 sleep_flags = lock_system_sleep();
321
322 level = TEST_FIRST;
323 for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
324 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
325 pm_test_level = level;
326 error = 0;
327 break;
328 }
329
330 unlock_system_sleep(sleep_flags);
331
332 return error ? error : n;
333}
334
335power_attr(pm_test);
336#endif /* CONFIG_PM_SLEEP_DEBUG */
337
338static char *suspend_step_name(enum suspend_stat_step step)
339{
340 switch (step) {
341 case SUSPEND_FREEZE:
342 return "freeze";
343 case SUSPEND_PREPARE:
344 return "prepare";
345 case SUSPEND_SUSPEND:
346 return "suspend";
347 case SUSPEND_SUSPEND_NOIRQ:
348 return "suspend_noirq";
349 case SUSPEND_RESUME_NOIRQ:
350 return "resume_noirq";
351 case SUSPEND_RESUME:
352 return "resume";
353 default:
354 return "";
355 }
356}
357
358#define suspend_attr(_name, format_str) \
359static ssize_t _name##_show(struct kobject *kobj, \
360 struct kobj_attribute *attr, char *buf) \
361{ \
362 return sprintf(buf, format_str, suspend_stats._name); \
363} \
364static struct kobj_attribute _name = __ATTR_RO(_name)
365
366suspend_attr(success, "%d\n");
367suspend_attr(fail, "%d\n");
368suspend_attr(failed_freeze, "%d\n");
369suspend_attr(failed_prepare, "%d\n");
370suspend_attr(failed_suspend, "%d\n");
371suspend_attr(failed_suspend_late, "%d\n");
372suspend_attr(failed_suspend_noirq, "%d\n");
373suspend_attr(failed_resume, "%d\n");
374suspend_attr(failed_resume_early, "%d\n");
375suspend_attr(failed_resume_noirq, "%d\n");
376suspend_attr(last_hw_sleep, "%llu\n");
377suspend_attr(total_hw_sleep, "%llu\n");
378suspend_attr(max_hw_sleep, "%llu\n");
379
380static ssize_t last_failed_dev_show(struct kobject *kobj,
381 struct kobj_attribute *attr, char *buf)
382{
383 int index;
384 char *last_failed_dev = NULL;
385
386 index = suspend_stats.last_failed_dev + REC_FAILED_NUM - 1;
387 index %= REC_FAILED_NUM;
388 last_failed_dev = suspend_stats.failed_devs[index];
389
390 return sprintf(buf, fmt: "%s\n", last_failed_dev);
391}
392static struct kobj_attribute last_failed_dev = __ATTR_RO(last_failed_dev);
393
394static ssize_t last_failed_errno_show(struct kobject *kobj,
395 struct kobj_attribute *attr, char *buf)
396{
397 int index;
398 int last_failed_errno;
399
400 index = suspend_stats.last_failed_errno + REC_FAILED_NUM - 1;
401 index %= REC_FAILED_NUM;
402 last_failed_errno = suspend_stats.errno[index];
403
404 return sprintf(buf, fmt: "%d\n", last_failed_errno);
405}
406static struct kobj_attribute last_failed_errno = __ATTR_RO(last_failed_errno);
407
408static ssize_t last_failed_step_show(struct kobject *kobj,
409 struct kobj_attribute *attr, char *buf)
410{
411 int index;
412 enum suspend_stat_step step;
413 char *last_failed_step = NULL;
414
415 index = suspend_stats.last_failed_step + REC_FAILED_NUM - 1;
416 index %= REC_FAILED_NUM;
417 step = suspend_stats.failed_steps[index];
418 last_failed_step = suspend_step_name(step);
419
420 return sprintf(buf, fmt: "%s\n", last_failed_step);
421}
422static struct kobj_attribute last_failed_step = __ATTR_RO(last_failed_step);
423
424static struct attribute *suspend_attrs[] = {
425 &success.attr,
426 &fail.attr,
427 &failed_freeze.attr,
428 &failed_prepare.attr,
429 &failed_suspend.attr,
430 &failed_suspend_late.attr,
431 &failed_suspend_noirq.attr,
432 &failed_resume.attr,
433 &failed_resume_early.attr,
434 &failed_resume_noirq.attr,
435 &last_failed_dev.attr,
436 &last_failed_errno.attr,
437 &last_failed_step.attr,
438 &last_hw_sleep.attr,
439 &total_hw_sleep.attr,
440 &max_hw_sleep.attr,
441 NULL,
442};
443
444static umode_t suspend_attr_is_visible(struct kobject *kobj, struct attribute *attr, int idx)
445{
446 if (attr != &last_hw_sleep.attr &&
447 attr != &total_hw_sleep.attr &&
448 attr != &max_hw_sleep.attr)
449 return 0444;
450
451#ifdef CONFIG_ACPI
452 if (acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0)
453 return 0444;
454#endif
455 return 0;
456}
457
458static const struct attribute_group suspend_attr_group = {
459 .name = "suspend_stats",
460 .attrs = suspend_attrs,
461 .is_visible = suspend_attr_is_visible,
462};
463
464#ifdef CONFIG_DEBUG_FS
465static int suspend_stats_show(struct seq_file *s, void *unused)
466{
467 int i, index, last_dev, last_errno, last_step;
468
469 last_dev = suspend_stats.last_failed_dev + REC_FAILED_NUM - 1;
470 last_dev %= REC_FAILED_NUM;
471 last_errno = suspend_stats.last_failed_errno + REC_FAILED_NUM - 1;
472 last_errno %= REC_FAILED_NUM;
473 last_step = suspend_stats.last_failed_step + REC_FAILED_NUM - 1;
474 last_step %= REC_FAILED_NUM;
475 seq_printf(m: s, fmt: "%s: %d\n%s: %d\n%s: %d\n%s: %d\n%s: %d\n"
476 "%s: %d\n%s: %d\n%s: %d\n%s: %d\n%s: %d\n",
477 "success", suspend_stats.success,
478 "fail", suspend_stats.fail,
479 "failed_freeze", suspend_stats.failed_freeze,
480 "failed_prepare", suspend_stats.failed_prepare,
481 "failed_suspend", suspend_stats.failed_suspend,
482 "failed_suspend_late",
483 suspend_stats.failed_suspend_late,
484 "failed_suspend_noirq",
485 suspend_stats.failed_suspend_noirq,
486 "failed_resume", suspend_stats.failed_resume,
487 "failed_resume_early",
488 suspend_stats.failed_resume_early,
489 "failed_resume_noirq",
490 suspend_stats.failed_resume_noirq);
491 seq_printf(m: s, fmt: "failures:\n last_failed_dev:\t%-s\n",
492 suspend_stats.failed_devs[last_dev]);
493 for (i = 1; i < REC_FAILED_NUM; i++) {
494 index = last_dev + REC_FAILED_NUM - i;
495 index %= REC_FAILED_NUM;
496 seq_printf(m: s, fmt: "\t\t\t%-s\n",
497 suspend_stats.failed_devs[index]);
498 }
499 seq_printf(m: s, fmt: " last_failed_errno:\t%-d\n",
500 suspend_stats.errno[last_errno]);
501 for (i = 1; i < REC_FAILED_NUM; i++) {
502 index = last_errno + REC_FAILED_NUM - i;
503 index %= REC_FAILED_NUM;
504 seq_printf(m: s, fmt: "\t\t\t%-d\n",
505 suspend_stats.errno[index]);
506 }
507 seq_printf(m: s, fmt: " last_failed_step:\t%-s\n",
508 suspend_step_name(
509 step: suspend_stats.failed_steps[last_step]));
510 for (i = 1; i < REC_FAILED_NUM; i++) {
511 index = last_step + REC_FAILED_NUM - i;
512 index %= REC_FAILED_NUM;
513 seq_printf(m: s, fmt: "\t\t\t%-s\n",
514 suspend_step_name(
515 step: suspend_stats.failed_steps[index]));
516 }
517
518 return 0;
519}
520DEFINE_SHOW_ATTRIBUTE(suspend_stats);
521
522static int __init pm_debugfs_init(void)
523{
524 debugfs_create_file(name: "suspend_stats", S_IFREG | S_IRUGO,
525 NULL, NULL, fops: &suspend_stats_fops);
526 return 0;
527}
528
529late_initcall(pm_debugfs_init);
530#endif /* CONFIG_DEBUG_FS */
531
532#endif /* CONFIG_PM_SLEEP */
533
534#ifdef CONFIG_PM_SLEEP_DEBUG
535/*
536 * pm_print_times: print time taken by devices to suspend and resume.
537 *
538 * show() returns whether printing of suspend and resume times is enabled.
539 * store() accepts 0 or 1. 0 disables printing and 1 enables it.
540 */
541bool pm_print_times_enabled;
542
543static ssize_t pm_print_times_show(struct kobject *kobj,
544 struct kobj_attribute *attr, char *buf)
545{
546 return sprintf(buf, fmt: "%d\n", pm_print_times_enabled);
547}
548
549static ssize_t pm_print_times_store(struct kobject *kobj,
550 struct kobj_attribute *attr,
551 const char *buf, size_t n)
552{
553 unsigned long val;
554
555 if (kstrtoul(s: buf, base: 10, res: &val))
556 return -EINVAL;
557
558 if (val > 1)
559 return -EINVAL;
560
561 pm_print_times_enabled = !!val;
562 return n;
563}
564
565power_attr(pm_print_times);
566
567static inline void pm_print_times_init(void)
568{
569 pm_print_times_enabled = !!initcall_debug;
570}
571
572static ssize_t pm_wakeup_irq_show(struct kobject *kobj,
573 struct kobj_attribute *attr,
574 char *buf)
575{
576 if (!pm_wakeup_irq())
577 return -ENODATA;
578
579 return sprintf(buf, fmt: "%u\n", pm_wakeup_irq());
580}
581
582power_attr_ro(pm_wakeup_irq);
583
584bool pm_debug_messages_on __read_mostly;
585
586bool pm_debug_messages_should_print(void)
587{
588 return pm_debug_messages_on && pm_suspend_target_state != PM_SUSPEND_ON;
589}
590EXPORT_SYMBOL_GPL(pm_debug_messages_should_print);
591
592static ssize_t pm_debug_messages_show(struct kobject *kobj,
593 struct kobj_attribute *attr, char *buf)
594{
595 return sprintf(buf, fmt: "%d\n", pm_debug_messages_on);
596}
597
598static ssize_t pm_debug_messages_store(struct kobject *kobj,
599 struct kobj_attribute *attr,
600 const char *buf, size_t n)
601{
602 unsigned long val;
603
604 if (kstrtoul(s: buf, base: 10, res: &val))
605 return -EINVAL;
606
607 if (val > 1)
608 return -EINVAL;
609
610 pm_debug_messages_on = !!val;
611 return n;
612}
613
614power_attr(pm_debug_messages);
615
616static int __init pm_debug_messages_setup(char *str)
617{
618 pm_debug_messages_on = true;
619 return 1;
620}
621__setup("pm_debug_messages", pm_debug_messages_setup);
622
623#else /* !CONFIG_PM_SLEEP_DEBUG */
624static inline void pm_print_times_init(void) {}
625#endif /* CONFIG_PM_SLEEP_DEBUG */
626
627struct kobject *power_kobj;
628
629/*
630 * state - control system sleep states.
631 *
632 * show() returns available sleep state labels, which may be "mem", "standby",
633 * "freeze" and "disk" (hibernation).
634 * See Documentation/admin-guide/pm/sleep-states.rst for a description of
635 * what they mean.
636 *
637 * store() accepts one of those strings, translates it into the proper
638 * enumerated value, and initiates a suspend transition.
639 */
640static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
641 char *buf)
642{
643 char *s = buf;
644#ifdef CONFIG_SUSPEND
645 suspend_state_t i;
646
647 for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
648 if (pm_states[i])
649 s += sprintf(buf: s,fmt: "%s ", pm_states[i]);
650
651#endif
652 if (hibernation_available())
653 s += sprintf(buf: s, fmt: "disk ");
654 if (s != buf)
655 /* convert the last space to a newline */
656 *(s-1) = '\n';
657 return (s - buf);
658}
659
660static suspend_state_t decode_state(const char *buf, size_t n)
661{
662#ifdef CONFIG_SUSPEND
663 suspend_state_t state;
664#endif
665 char *p;
666 int len;
667
668 p = memchr(p: buf, c: '\n', size: n);
669 len = p ? p - buf : n;
670
671 /* Check hibernation first. */
672 if (len == 4 && str_has_prefix(str: buf, prefix: "disk"))
673 return PM_SUSPEND_MAX;
674
675#ifdef CONFIG_SUSPEND
676 for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) {
677 const char *label = pm_states[state];
678
679 if (label && len == strlen(label) && !strncmp(buf, label, len))
680 return state;
681 }
682#endif
683
684 return PM_SUSPEND_ON;
685}
686
687static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
688 const char *buf, size_t n)
689{
690 suspend_state_t state;
691 int error;
692
693 error = pm_autosleep_lock();
694 if (error)
695 return error;
696
697 if (pm_autosleep_state() > PM_SUSPEND_ON) {
698 error = -EBUSY;
699 goto out;
700 }
701
702 state = decode_state(buf, n);
703 if (state < PM_SUSPEND_MAX) {
704 if (state == PM_SUSPEND_MEM)
705 state = mem_sleep_current;
706
707 error = pm_suspend(state);
708 } else if (state == PM_SUSPEND_MAX) {
709 error = hibernate();
710 } else {
711 error = -EINVAL;
712 }
713
714 out:
715 pm_autosleep_unlock();
716 return error ? error : n;
717}
718
719power_attr(state);
720
721#ifdef CONFIG_PM_SLEEP
722/*
723 * The 'wakeup_count' attribute, along with the functions defined in
724 * drivers/base/power/wakeup.c, provides a means by which wakeup events can be
725 * handled in a non-racy way.
726 *
727 * If a wakeup event occurs when the system is in a sleep state, it simply is
728 * woken up. In turn, if an event that would wake the system up from a sleep
729 * state occurs when it is undergoing a transition to that sleep state, the
730 * transition should be aborted. Moreover, if such an event occurs when the
731 * system is in the working state, an attempt to start a transition to the
732 * given sleep state should fail during certain period after the detection of
733 * the event. Using the 'state' attribute alone is not sufficient to satisfy
734 * these requirements, because a wakeup event may occur exactly when 'state'
735 * is being written to and may be delivered to user space right before it is
736 * frozen, so the event will remain only partially processed until the system is
737 * woken up by another event. In particular, it won't cause the transition to
738 * a sleep state to be aborted.
739 *
740 * This difficulty may be overcome if user space uses 'wakeup_count' before
741 * writing to 'state'. It first should read from 'wakeup_count' and store
742 * the read value. Then, after carrying out its own preparations for the system
743 * transition to a sleep state, it should write the stored value to
744 * 'wakeup_count'. If that fails, at least one wakeup event has occurred since
745 * 'wakeup_count' was read and 'state' should not be written to. Otherwise, it
746 * is allowed to write to 'state', but the transition will be aborted if there
747 * are any wakeup events detected after 'wakeup_count' was written to.
748 */
749
750static ssize_t wakeup_count_show(struct kobject *kobj,
751 struct kobj_attribute *attr,
752 char *buf)
753{
754 unsigned int val;
755
756 return pm_get_wakeup_count(count: &val, block: true) ?
757 sprintf(buf, fmt: "%u\n", val) : -EINTR;
758}
759
760static ssize_t wakeup_count_store(struct kobject *kobj,
761 struct kobj_attribute *attr,
762 const char *buf, size_t n)
763{
764 unsigned int val;
765 int error;
766
767 error = pm_autosleep_lock();
768 if (error)
769 return error;
770
771 if (pm_autosleep_state() > PM_SUSPEND_ON) {
772 error = -EBUSY;
773 goto out;
774 }
775
776 error = -EINVAL;
777 if (sscanf(buf, "%u", &val) == 1) {
778 if (pm_save_wakeup_count(count: val))
779 error = n;
780 else
781 pm_print_active_wakeup_sources();
782 }
783
784 out:
785 pm_autosleep_unlock();
786 return error;
787}
788
789power_attr(wakeup_count);
790
791#ifdef CONFIG_PM_AUTOSLEEP
792static ssize_t autosleep_show(struct kobject *kobj,
793 struct kobj_attribute *attr,
794 char *buf)
795{
796 suspend_state_t state = pm_autosleep_state();
797
798 if (state == PM_SUSPEND_ON)
799 return sprintf(buf, fmt: "off\n");
800
801#ifdef CONFIG_SUSPEND
802 if (state < PM_SUSPEND_MAX)
803 return sprintf(buf, fmt: "%s\n", pm_states[state] ?
804 pm_states[state] : "error");
805#endif
806#ifdef CONFIG_HIBERNATION
807 return sprintf(buf, fmt: "disk\n");
808#else
809 return sprintf(buf, "error");
810#endif
811}
812
813static ssize_t autosleep_store(struct kobject *kobj,
814 struct kobj_attribute *attr,
815 const char *buf, size_t n)
816{
817 suspend_state_t state = decode_state(buf, n);
818 int error;
819
820 if (state == PM_SUSPEND_ON
821 && strcmp(buf, "off") && strcmp(buf, "off\n"))
822 return -EINVAL;
823
824 if (state == PM_SUSPEND_MEM)
825 state = mem_sleep_current;
826
827 error = pm_autosleep_set_state(state);
828 return error ? error : n;
829}
830
831power_attr(autosleep);
832#endif /* CONFIG_PM_AUTOSLEEP */
833
834#ifdef CONFIG_PM_WAKELOCKS
835static ssize_t wake_lock_show(struct kobject *kobj,
836 struct kobj_attribute *attr,
837 char *buf)
838{
839 return pm_show_wakelocks(buf, show_active: true);
840}
841
842static ssize_t wake_lock_store(struct kobject *kobj,
843 struct kobj_attribute *attr,
844 const char *buf, size_t n)
845{
846 int error = pm_wake_lock(buf);
847 return error ? error : n;
848}
849
850power_attr(wake_lock);
851
852static ssize_t wake_unlock_show(struct kobject *kobj,
853 struct kobj_attribute *attr,
854 char *buf)
855{
856 return pm_show_wakelocks(buf, show_active: false);
857}
858
859static ssize_t wake_unlock_store(struct kobject *kobj,
860 struct kobj_attribute *attr,
861 const char *buf, size_t n)
862{
863 int error = pm_wake_unlock(buf);
864 return error ? error : n;
865}
866
867power_attr(wake_unlock);
868
869#endif /* CONFIG_PM_WAKELOCKS */
870#endif /* CONFIG_PM_SLEEP */
871
872#ifdef CONFIG_PM_TRACE
873int pm_trace_enabled;
874
875static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
876 char *buf)
877{
878 return sprintf(buf, fmt: "%d\n", pm_trace_enabled);
879}
880
881static ssize_t
882pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
883 const char *buf, size_t n)
884{
885 int val;
886
887 if (sscanf(buf, "%d", &val) == 1) {
888 pm_trace_enabled = !!val;
889 if (pm_trace_enabled) {
890 pr_warn("PM: Enabling pm_trace changes system date and time during resume.\n"
891 "PM: Correct system time has to be restored manually after resume.\n");
892 }
893 return n;
894 }
895 return -EINVAL;
896}
897
898power_attr(pm_trace);
899
900static ssize_t pm_trace_dev_match_show(struct kobject *kobj,
901 struct kobj_attribute *attr,
902 char *buf)
903{
904 return show_trace_dev_match(buf, PAGE_SIZE);
905}
906
907power_attr_ro(pm_trace_dev_match);
908
909#endif /* CONFIG_PM_TRACE */
910
911#ifdef CONFIG_FREEZER
912static ssize_t pm_freeze_timeout_show(struct kobject *kobj,
913 struct kobj_attribute *attr, char *buf)
914{
915 return sprintf(buf, fmt: "%u\n", freeze_timeout_msecs);
916}
917
918static ssize_t pm_freeze_timeout_store(struct kobject *kobj,
919 struct kobj_attribute *attr,
920 const char *buf, size_t n)
921{
922 unsigned long val;
923
924 if (kstrtoul(s: buf, base: 10, res: &val))
925 return -EINVAL;
926
927 freeze_timeout_msecs = val;
928 return n;
929}
930
931power_attr(pm_freeze_timeout);
932
933#endif /* CONFIG_FREEZER*/
934
935static struct attribute * g[] = {
936 &state_attr.attr,
937#ifdef CONFIG_PM_TRACE
938 &pm_trace_attr.attr,
939 &pm_trace_dev_match_attr.attr,
940#endif
941#ifdef CONFIG_PM_SLEEP
942 &pm_async_attr.attr,
943 &wakeup_count_attr.attr,
944#ifdef CONFIG_SUSPEND
945 &mem_sleep_attr.attr,
946 &sync_on_suspend_attr.attr,
947#endif
948#ifdef CONFIG_PM_AUTOSLEEP
949 &autosleep_attr.attr,
950#endif
951#ifdef CONFIG_PM_WAKELOCKS
952 &wake_lock_attr.attr,
953 &wake_unlock_attr.attr,
954#endif
955#ifdef CONFIG_PM_SLEEP_DEBUG
956 &pm_test_attr.attr,
957 &pm_print_times_attr.attr,
958 &pm_wakeup_irq_attr.attr,
959 &pm_debug_messages_attr.attr,
960#endif
961#endif
962#ifdef CONFIG_FREEZER
963 &pm_freeze_timeout_attr.attr,
964#endif
965 NULL,
966};
967
968static const struct attribute_group attr_group = {
969 .attrs = g,
970};
971
972static const struct attribute_group *attr_groups[] = {
973 &attr_group,
974#ifdef CONFIG_PM_SLEEP
975 &suspend_attr_group,
976#endif
977 NULL,
978};
979
980struct workqueue_struct *pm_wq;
981EXPORT_SYMBOL_GPL(pm_wq);
982
983static int __init pm_start_workqueue(void)
984{
985 pm_wq = alloc_workqueue(fmt: "pm", flags: WQ_FREEZABLE, max_active: 0);
986
987 return pm_wq ? 0 : -ENOMEM;
988}
989
990static int __init pm_init(void)
991{
992 int error = pm_start_workqueue();
993 if (error)
994 return error;
995 hibernate_image_size_init();
996 hibernate_reserved_size_init();
997 pm_states_init();
998 power_kobj = kobject_create_and_add(name: "power", NULL);
999 if (!power_kobj)
1000 return -ENOMEM;
1001 error = sysfs_create_groups(kobj: power_kobj, groups: attr_groups);
1002 if (error)
1003 return error;
1004 pm_print_times_init();
1005 return pm_autosleep_init();
1006}
1007
1008core_initcall(pm_init);
1009

source code of linux/kernel/power/main.c