kernel/power/main.c

   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  */
  33 static gfp_t saved_gfp_mask;
  34
  35 void 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
  44 void 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
  52 unsigned 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 }
  59 EXPORT_SYMBOL_GPL(lock_system_sleep);
  60
  61 void 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(&system_transition_mutex);
  82 }
  83 EXPORT_SYMBOL_GPL(unlock_system_sleep);
  84
  85 void 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 }
  96 EXPORT_SYMBOL_GPL(ksys_sync_helper);
  97
  98 /* Routines for PM-transition notifications */
  99
 100 static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
 101
 102 int register_pm_notifier(struct notifier_block *nb)
 103 {
 104         return blocking_notifier_chain_register(&pm_chain_head, nb);
 105 }
 106 EXPORT_SYMBOL_GPL(register_pm_notifier);
 107
 108 int unregister_pm_notifier(struct notifier_block *nb)
 109 {
 110         return blocking_notifier_chain_unregister(&pm_chain_head, nb);
 111 }
 112 EXPORT_SYMBOL_GPL(unregister_pm_notifier);
 113
 114 void pm_report_hw_sleep_time(u64 t)
 115 {
 116         suspend_stats.last_hw_sleep = t;
 117         suspend_stats.total_hw_sleep += t;
 118 }
 119 EXPORT_SYMBOL_GPL(pm_report_hw_sleep_time);
 120
 121 void pm_report_max_hw_sleep(u64 t)
 122 {
 123         suspend_stats.max_hw_sleep = t;
 124 }
 125 EXPORT_SYMBOL_GPL(pm_report_max_hw_sleep);
 126
 127 int 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(&pm_chain_head, val_up, val_down, NULL);
 132
 133         return notifier_to_errno(ret);
 134 }
 135
 136 int pm_notifier_call_chain(unsigned long val)
 137 {
 138         return blocking_notifier_call_chain(&pm_chain_head, val, NULL);
 139 }
 140
 141 /* If set, devices may be suspended and resumed asynchronously. */
 142 int pm_async_enabled = 1;
 143
 144 static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr,
 145                              char *buf)
 146 {
 147         return sprintf(buf, "%d\n", pm_async_enabled);
 148 }
 149
 150 static 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(buf, 10, &val))
 156                 return -EINVAL;
 157
 158         if (val > 1)
 159                 return -EINVAL;
 160
 161         pm_async_enabled = val;
 162         return n;
 163 }
 164
 165 power_attr(pm_async);
 166
 167 #ifdef CONFIG_SUSPEND
 168 static 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(s, "[%s] ", label);
 182                         else
 183                                 s += sprintf(s, "%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
 194 static 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(buf, '\n', 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
 213 static 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
 239 power_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  */
 247 bool sync_on_suspend_enabled = !IS_ENABLED(CONFIG_SUSPEND_SKIP_SYNC);
 248
 249 static ssize_t sync_on_suspend_show(struct kobject *kobj,
 250                                    struct kobj_attribute *attr, char *buf)
 251 {
 252         return sprintf(buf, "%d\n", sync_on_suspend_enabled);
 253 }
 254
 255 static 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(buf, 10, &val))
 262                 return -EINVAL;
 263
 264         if (val > 1)
 265                 return -EINVAL;
 266
 267         sync_on_suspend_enabled = !!val;
 268         return n;
 269 }
 270
 271 power_attr(sync_on_suspend);
 272 #endif /* CONFIG_SUSPEND */
 273
 274 #ifdef CONFIG_PM_SLEEP_DEBUG
 275 int pm_test_level = TEST_NONE;
 276
 277 static 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
 286 static 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(s, "[%s] ", pm_tests[level]);
 296                         else
 297                                 s += sprintf(s, "%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
 307 static 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(buf, '\n', 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
 335 power_attr(pm_test);
 336 #endif /* CONFIG_PM_SLEEP_DEBUG */
 337
 338 static 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)                         \
 359 static 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 }                                                               \
 364 static struct kobj_attribute _name = __ATTR_RO(_name)
 365
 366 suspend_attr(success, "%d\n");
 367 suspend_attr(fail, "%d\n");
 368 suspend_attr(failed_freeze, "%d\n");
 369 suspend_attr(failed_prepare, "%d\n");
 370 suspend_attr(failed_suspend, "%d\n");
 371 suspend_attr(failed_suspend_late, "%d\n");
 372 suspend_attr(failed_suspend_noirq, "%d\n");
 373 suspend_attr(failed_resume, "%d\n");
 374 suspend_attr(failed_resume_early, "%d\n");
 375 suspend_attr(failed_resume_noirq, "%d\n");
 376 suspend_attr(last_hw_sleep, "%llu\n");
 377 suspend_attr(total_hw_sleep, "%llu\n");
 378 suspend_attr(max_hw_sleep, "%llu\n");
 379
 380 static 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, "%s\n", last_failed_dev);
 391 }
 392 static struct kobj_attribute last_failed_dev = __ATTR_RO(last_failed_dev);
 393
 394 static 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, "%d\n", last_failed_errno);
 405 }
 406 static struct kobj_attribute last_failed_errno = __ATTR_RO(last_failed_errno);
 407
 408 static 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, "%s\n", last_failed_step);
 421 }
 422 static struct kobj_attribute last_failed_step = __ATTR_RO(last_failed_step);
 423
 424 static 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
 444 static 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
 458 static 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
 465 static 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(s, "%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(s,   "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(s, "\t\t\t%-s\n",
 497                         suspend_stats.failed_devs[index]);
 498         }
 499         seq_printf(s,   "  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(s, "\t\t\t%-d\n",
 505                         suspend_stats.errno[index]);
 506         }
 507         seq_printf(s,   "  last_failed_step:\t%-s\n",
 508                         suspend_step_name(
 509                                 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(s, "\t\t\t%-s\n",
 514                         suspend_step_name(
 515                                 suspend_stats.failed_steps[index]));
 516         }
 517
 518         return 0;
 519 }
 520 DEFINE_SHOW_ATTRIBUTE(suspend_stats);
 521
 522 static int __init pm_debugfs_init(void)
 523 {
 524         debugfs_create_file("suspend_stats", S_IFREG | S_IRUGO,
 525                         NULL, NULL, &suspend_stats_fops);
 526         return 0;
 527 }
 528
 529 late_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  */
 541 bool pm_print_times_enabled;
 542
 543 static ssize_t pm_print_times_show(struct kobject *kobj,
 544                                    struct kobj_attribute *attr, char *buf)
 545 {
 546         return sprintf(buf, "%d\n", pm_print_times_enabled);
 547 }
 548
 549 static 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(buf, 10, &val))
 556                 return -EINVAL;
 557
 558         if (val > 1)
 559                 return -EINVAL;
 560
 561         pm_print_times_enabled = !!val;
 562         return n;
 563 }
 564
 565 power_attr(pm_print_times);
 566
 567 static inline void pm_print_times_init(void)
 568 {
 569         pm_print_times_enabled = !!initcall_debug;
 570 }
 571
 572 static 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, "%u\n", pm_wakeup_irq());
 580 }
 581
 582 power_attr_ro(pm_wakeup_irq);
 583
 584 bool pm_debug_messages_on __read_mostly;
 585
 586 bool pm_debug_messages_should_print(void)
 587 {
 588         return pm_debug_messages_on && pm_suspend_target_state != PM_SUSPEND_ON;
 589 }
 590 EXPORT_SYMBOL_GPL(pm_debug_messages_should_print);
 591
 592 static ssize_t pm_debug_messages_show(struct kobject *kobj,
 593                                       struct kobj_attribute *attr, char *buf)
 594 {
 595         return sprintf(buf, "%d\n", pm_debug_messages_on);
 596 }
 597
 598 static 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(buf, 10, &val))
 605                 return -EINVAL;
 606
 607         if (val > 1)
 608                 return -EINVAL;
 609
 610         pm_debug_messages_on = !!val;
 611         return n;
 612 }
 613
 614 power_attr(pm_debug_messages);
 615
 616 static 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 */
 624 static inline void pm_print_times_init(void) {}
 625 #endif /* CONFIG_PM_SLEEP_DEBUG */
 626
 627 struct 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  */
 640 static 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(s,"%s ", pm_states[i]);
 650
 651 #endif
 652         if (hibernation_available())
 653                 s += sprintf(s, "disk ");
 654         if (s != buf)
 655                 /* convert the last space to a newline */
 656                 *(s-1) = '\n';
 657         return (s - buf);
 658 }
 659
 660 static 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(buf, '\n', n);
 669         len = p ? p - buf : n;
 670
 671         /* Check hibernation first. */
 672         if (len == 4 && str_has_prefix(buf, "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
 687 static 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
 719 power_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
 750 static 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(&val, true) ?
 757                 sprintf(buf, "%u\n", val) : -EINTR;
 758 }
 759
 760 static 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(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
 789 power_attr(wakeup_count);
 790
 791 #ifdef CONFIG_PM_AUTOSLEEP
 792 static 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, "off\n");
 800
 801 #ifdef CONFIG_SUSPEND
 802         if (state < PM_SUSPEND_MAX)
 803                 return sprintf(buf, "%s\n", pm_states[state] ?
 804                                         pm_states[state] : "error");
 805 #endif
 806 #ifdef CONFIG_HIBERNATION
 807         return sprintf(buf, "disk\n");
 808 #else
 809         return sprintf(buf, "error");
 810 #endif
 811 }
 812
 813 static 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
 831 power_attr(autosleep);
 832 #endif /* CONFIG_PM_AUTOSLEEP */
 833
 834 #ifdef CONFIG_PM_WAKELOCKS
 835 static ssize_t wake_lock_show(struct kobject *kobj,
 836                               struct kobj_attribute *attr,
 837                               char *buf)
 838 {
 839         return pm_show_wakelocks(buf, true);
 840 }
 841
 842 static 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
 850 power_attr(wake_lock);
 851
 852 static ssize_t wake_unlock_show(struct kobject *kobj,
 853                                 struct kobj_attribute *attr,
 854                                 char *buf)
 855 {
 856         return pm_show_wakelocks(buf, false);
 857 }
 858
 859 static 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
 867 power_attr(wake_unlock);
 868
 869 #endif /* CONFIG_PM_WAKELOCKS */
 870 #endif /* CONFIG_PM_SLEEP */
 871
 872 #ifdef CONFIG_PM_TRACE
 873 int pm_trace_enabled;
 874
 875 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
 876                              char *buf)
 877 {
 878         return sprintf(buf, "%d\n", pm_trace_enabled);
 879 }
 880
 881 static ssize_t
 882 pm_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
 898 power_attr(pm_trace);
 899
 900 static 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
 907 power_attr_ro(pm_trace_dev_match);
 908
 909 #endif /* CONFIG_PM_TRACE */
 910
 911 #ifdef CONFIG_FREEZER
 912 static ssize_t pm_freeze_timeout_show(struct kobject *kobj,
 913                                       struct kobj_attribute *attr, char *buf)
 914 {
 915         return sprintf(buf, "%u\n", freeze_timeout_msecs);
 916 }
 917
 918 static 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(buf, 10, &val))
 925                 return -EINVAL;
 926
 927         freeze_timeout_msecs = val;
 928         return n;
 929 }
 930
 931 power_attr(pm_freeze_timeout);
 932
 933 #endif  /* CONFIG_FREEZER*/
 934
 935 static 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
 968 static const struct attribute_group attr_group = {
 969         .attrs = g,
 970 };
 971
 972 static const struct attribute_group *attr_groups[] = {
 973         &attr_group,
 974 #ifdef CONFIG_PM_SLEEP
 975         &suspend_attr_group,
 976 #endif
 977         NULL,
 978 };
 979
 980 struct workqueue_struct *pm_wq;
 981 EXPORT_SYMBOL_GPL(pm_wq);
 982
 983 static int __init pm_start_workqueue(void)
 984 {
 985         pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0);
 986
 987         return pm_wq ? 0 : -ENOMEM;
 988 }
 989
 990 static 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("power", NULL);
 999         if (!power_kobj)
1000                 return -ENOMEM;
1001         error = sysfs_create_groups(power_kobj, attr_groups);
1002         if (error)
1003                 return error;
1004         pm_print_times_init();
1005         return pm_autosleep_init();
1006 }
1007
1008 core_initcall(pm_init);