include/linux/suspend.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_SUSPEND_H
   3 #define _LINUX_SUSPEND_H
   4
   5 #include <linux/swap.h>
   6 #include <linux/notifier.h>
   7 #include <linux/init.h>
   8 #include <linux/pm.h>
   9 #include <linux/mm.h>
  10 #include <linux/freezer.h>
  11 #include <asm/errno.h>
  12
  13 #ifdef CONFIG_VT
  14 extern void pm_set_vt_switch(int);
  15 #else
  16 static inline void pm_set_vt_switch(int do_switch)
  17 {
  18 }
  19 #endif
  20
  21 #ifdef CONFIG_VT_CONSOLE_SLEEP
  22 extern void pm_prepare_console(void);
  23 extern void pm_restore_console(void);
  24 #else
  25 static inline void pm_prepare_console(void)
  26 {
  27 }
  28
  29 static inline void pm_restore_console(void)
  30 {
  31 }
  32 #endif
  33
  34 typedef int __bitwise suspend_state_t;
  35
  36 #define PM_SUSPEND_ON           ((__force suspend_state_t) 0)
  37 #define PM_SUSPEND_TO_IDLE      ((__force suspend_state_t) 1)
  38 #define PM_SUSPEND_STANDBY      ((__force suspend_state_t) 2)
  39 #define PM_SUSPEND_MEM          ((__force suspend_state_t) 3)
  40 #define PM_SUSPEND_MIN          PM_SUSPEND_TO_IDLE
  41 #define PM_SUSPEND_MAX          ((__force suspend_state_t) 4)
  42
  43 enum suspend_stat_step {
  44         SUSPEND_FREEZE = 1,
  45         SUSPEND_PREPARE,
  46         SUSPEND_SUSPEND,
  47         SUSPEND_SUSPEND_LATE,
  48         SUSPEND_SUSPEND_NOIRQ,
  49         SUSPEND_RESUME_NOIRQ,
  50         SUSPEND_RESUME_EARLY,
  51         SUSPEND_RESUME
  52 };
  53
  54 struct suspend_stats {
  55         int     success;
  56         int     fail;
  57         int     failed_freeze;
  58         int     failed_prepare;
  59         int     failed_suspend;
  60         int     failed_suspend_late;
  61         int     failed_suspend_noirq;
  62         int     failed_resume;
  63         int     failed_resume_early;
  64         int     failed_resume_noirq;
  65 #define REC_FAILED_NUM  2
  66         int     last_failed_dev;
  67         char    failed_devs[REC_FAILED_NUM][40];
  68         int     last_failed_errno;
  69         int     errno[REC_FAILED_NUM];
  70         int     last_failed_step;
  71         enum suspend_stat_step  failed_steps[REC_FAILED_NUM];
  72 };
  73
  74 extern struct suspend_stats suspend_stats;
  75
  76 static inline void dpm_save_failed_dev(const char *name)
  77 {
  78         strlcpy(suspend_stats.failed_devs[suspend_stats.last_failed_dev],
  79                 name,
  80                 sizeof(suspend_stats.failed_devs[0]));
  81         suspend_stats.last_failed_dev++;
  82         suspend_stats.last_failed_dev %= REC_FAILED_NUM;
  83 }
  84
  85 static inline void dpm_save_failed_errno(int err)
  86 {
  87         suspend_stats.errno[suspend_stats.last_failed_errno] = err;
  88         suspend_stats.last_failed_errno++;
  89         suspend_stats.last_failed_errno %= REC_FAILED_NUM;
  90 }
  91
  92 static inline void dpm_save_failed_step(enum suspend_stat_step step)
  93 {
  94         suspend_stats.failed_steps[suspend_stats.last_failed_step] = step;
  95         suspend_stats.last_failed_step++;
  96         suspend_stats.last_failed_step %= REC_FAILED_NUM;
  97 }
  98
  99 /**
 100  * struct platform_suspend_ops - Callbacks for managing platform dependent
 101  *      system sleep states.
 102  *
 103  * @valid: Callback to determine if given system sleep state is supported by
 104  *      the platform.
 105  *      Valid (ie. supported) states are advertised in /sys/power/state.  Note
 106  *      that it still may be impossible to enter given system sleep state if the
 107  *      conditions aren't right.
 108  *      There is the %suspend_valid_only_mem function available that can be
 109  *      assigned to this if the platform only supports mem sleep.
 110  *
 111  * @begin: Initialise a transition to given system sleep state.
 112  *      @begin() is executed right prior to suspending devices.  The information
 113  *      conveyed to the platform code by @begin() should be disregarded by it as
 114  *      soon as @end() is executed.  If @begin() fails (ie. returns nonzero),
 115  *      @prepare(), @enter() and @finish() will not be called by the PM core.
 116  *      This callback is optional.  However, if it is implemented, the argument
 117  *      passed to @enter() is redundant and should be ignored.
 118  *
 119  * @prepare: Prepare the platform for entering the system sleep state indicated
 120  *      by @begin().
 121  *      @prepare() is called right after devices have been suspended (ie. the
 122  *      appropriate .suspend() method has been executed for each device) and
 123  *      before device drivers' late suspend callbacks are executed.  It returns
 124  *      0 on success or a negative error code otherwise, in which case the
 125  *      system cannot enter the desired sleep state (@prepare_late(), @enter(),
 126  *      and @wake() will not be called in that case).
 127  *
 128  * @prepare_late: Finish preparing the platform for entering the system sleep
 129  *      state indicated by @begin().
 130  *      @prepare_late is called before disabling nonboot CPUs and after
 131  *      device drivers' late suspend callbacks have been executed.  It returns
 132  *      0 on success or a negative error code otherwise, in which case the
 133  *      system cannot enter the desired sleep state (@enter() will not be
 134  *      executed).
 135  *
 136  * @enter: Enter the system sleep state indicated by @begin() or represented by
 137  *      the argument if @begin() is not implemented.
 138  *      This callback is mandatory.  It returns 0 on success or a negative
 139  *      error code otherwise, in which case the system cannot enter the desired
 140  *      sleep state.
 141  *
 142  * @wake: Called when the system has just left a sleep state, right after
 143  *      the nonboot CPUs have been enabled and before device drivers' early
 144  *      resume callbacks are executed.
 145  *      This callback is optional, but should be implemented by the platforms
 146  *      that implement @prepare_late().  If implemented, it is always called
 147  *      after @prepare_late and @enter(), even if one of them fails.
 148  *
 149  * @finish: Finish wake-up of the platform.
 150  *      @finish is called right prior to calling device drivers' regular suspend
 151  *      callbacks.
 152  *      This callback is optional, but should be implemented by the platforms
 153  *      that implement @prepare().  If implemented, it is always called after
 154  *      @enter() and @wake(), even if any of them fails.  It is executed after
 155  *      a failing @prepare.
 156  *
 157  * @suspend_again: Returns whether the system should suspend again (true) or
 158  *      not (false). If the platform wants to poll sensors or execute some
 159  *      code during suspended without invoking userspace and most of devices,
 160  *      suspend_again callback is the place assuming that periodic-wakeup or
 161  *      alarm-wakeup is already setup. This allows to execute some codes while
 162  *      being kept suspended in the view of userland and devices.
 163  *
 164  * @end: Called by the PM core right after resuming devices, to indicate to
 165  *      the platform that the system has returned to the working state or
 166  *      the transition to the sleep state has been aborted.
 167  *      This callback is optional, but should be implemented by the platforms
 168  *      that implement @begin().  Accordingly, platforms implementing @begin()
 169  *      should also provide a @end() which cleans up transitions aborted before
 170  *      @enter().
 171  *
 172  * @recover: Recover the platform from a suspend failure.
 173  *      Called by the PM core if the suspending of devices fails.
 174  *      This callback is optional and should only be implemented by platforms
 175  *      which require special recovery actions in that situation.
 176  */
 177 struct platform_suspend_ops {
 178         int (*valid)(suspend_state_t state);
 179         int (*begin)(suspend_state_t state);
 180         int (*prepare)(void);
 181         int (*prepare_late)(void);
 182         int (*enter)(suspend_state_t state);
 183         void (*wake)(void);
 184         void (*finish)(void);
 185         bool (*suspend_again)(void);
 186         void (*end)(void);
 187         void (*recover)(void);
 188 };
 189
 190 struct platform_s2idle_ops {
 191         int (*begin)(void);
 192         int (*prepare)(void);
 193         int (*prepare_late)(void);
 194         bool (*wake)(void);
 195         void (*restore_early)(void);
 196         void (*restore)(void);
 197         void (*end)(void);
 198 };
 199
 200 #ifdef CONFIG_SUSPEND
 201 extern suspend_state_t mem_sleep_current;
 202 extern suspend_state_t mem_sleep_default;
 203
 204 /**
 205  * suspend_set_ops - set platform dependent suspend operations
 206  * @ops: The new suspend operations to set.
 207  */
 208 extern void suspend_set_ops(const struct platform_suspend_ops *ops);
 209 extern int suspend_valid_only_mem(suspend_state_t state);
 210
 211 extern unsigned int pm_suspend_global_flags;
 212
 213 #define PM_SUSPEND_FLAG_FW_SUSPEND      BIT(0)
 214 #define PM_SUSPEND_FLAG_FW_RESUME       BIT(1)
 215 #define PM_SUSPEND_FLAG_NO_PLATFORM     BIT(2)
 216
 217 static inline void pm_suspend_clear_flags(void)
 218 {
 219         pm_suspend_global_flags = 0;
 220 }
 221
 222 static inline void pm_set_suspend_via_firmware(void)
 223 {
 224         pm_suspend_global_flags |= PM_SUSPEND_FLAG_FW_SUSPEND;
 225 }
 226
 227 static inline void pm_set_resume_via_firmware(void)
 228 {
 229         pm_suspend_global_flags |= PM_SUSPEND_FLAG_FW_RESUME;
 230 }
 231
 232 static inline void pm_set_suspend_no_platform(void)
 233 {
 234         pm_suspend_global_flags |= PM_SUSPEND_FLAG_NO_PLATFORM;
 235 }
 236
 237 /**
 238  * pm_suspend_via_firmware - Check if platform firmware will suspend the system.
 239  *
 240  * To be called during system-wide power management transitions to sleep states
 241  * or during the subsequent system-wide transitions back to the working state.
 242  *
 243  * Return 'true' if the platform firmware is going to be invoked at the end of
 244  * the system-wide power management transition (to a sleep state) in progress in
 245  * order to complete it, or if the platform firmware has been invoked in order
 246  * to complete the last (or preceding) transition of the system to a sleep
 247  * state.
 248  *
 249  * This matters if the caller needs or wants to carry out some special actions
 250  * depending on whether or not control will be passed to the platform firmware
 251  * subsequently (for example, the device may need to be reset before letting the
 252  * platform firmware manipulate it, which is not necessary when the platform
 253  * firmware is not going to be invoked) or when such special actions may have
 254  * been carried out during the preceding transition of the system to a sleep
 255  * state (as they may need to be taken into account).
 256  */
 257 static inline bool pm_suspend_via_firmware(void)
 258 {
 259         return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_FW_SUSPEND);
 260 }
 261
 262 /**
 263  * pm_resume_via_firmware - Check if platform firmware has woken up the system.
 264  *
 265  * To be called during system-wide power management transitions from sleep
 266  * states.
 267  *
 268  * Return 'true' if the platform firmware has passed control to the kernel at
 269  * the beginning of the system-wide power management transition in progress, so
 270  * the event that woke up the system from sleep has been handled by the platform
 271  * firmware.
 272  */
 273 static inline bool pm_resume_via_firmware(void)
 274 {
 275         return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_FW_RESUME);
 276 }
 277
 278 /**
 279  * pm_suspend_no_platform - Check if platform may change device power states.
 280  *
 281  * To be called during system-wide power management transitions to sleep states
 282  * or during the subsequent system-wide transitions back to the working state.
 283  *
 284  * Return 'true' if the power states of devices remain under full control of the
 285  * kernel throughout the system-wide suspend and resume cycle in progress (that
 286  * is, if a device is put into a certain power state during suspend, it can be
 287  * expected to remain in that state during resume).
 288  */
 289 static inline bool pm_suspend_no_platform(void)
 290 {
 291         return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_NO_PLATFORM);
 292 }
 293
 294 /* Suspend-to-idle state machnine. */
 295 enum s2idle_states {
 296         S2IDLE_STATE_NONE,      /* Not suspended/suspending. */
 297         S2IDLE_STATE_ENTER,     /* Enter suspend-to-idle. */
 298         S2IDLE_STATE_WAKE,      /* Wake up from suspend-to-idle. */
 299 };
 300
 301 extern enum s2idle_states __read_mostly s2idle_state;
 302
 303 static inline bool idle_should_enter_s2idle(void)
 304 {
 305         return unlikely(s2idle_state == S2IDLE_STATE_ENTER);
 306 }
 307
 308 extern bool pm_suspend_default_s2idle(void);
 309 extern void __init pm_states_init(void);
 310 extern void s2idle_set_ops(const struct platform_s2idle_ops *ops);
 311 extern void s2idle_wake(void);
 312
 313 /**
 314  * arch_suspend_disable_irqs - disable IRQs for suspend
 315  *
 316  * Disables IRQs (in the default case). This is a weak symbol in the common
 317  * code and thus allows architectures to override it if more needs to be
 318  * done. Not called for suspend to disk.
 319  */
 320 extern void arch_suspend_disable_irqs(void);
 321
 322 /**
 323  * arch_suspend_enable_irqs - enable IRQs after suspend
 324  *
 325  * Enables IRQs (in the default case). This is a weak symbol in the common
 326  * code and thus allows architectures to override it if more needs to be
 327  * done. Not called for suspend to disk.
 328  */
 329 extern void arch_suspend_enable_irqs(void);
 330
 331 extern int pm_suspend(suspend_state_t state);
 332 #else /* !CONFIG_SUSPEND */
 333 #define suspend_valid_only_mem  NULL
 334
 335 static inline void pm_suspend_clear_flags(void) {}
 336 static inline void pm_set_suspend_via_firmware(void) {}
 337 static inline void pm_set_resume_via_firmware(void) {}
 338 static inline bool pm_suspend_via_firmware(void) { return false; }
 339 static inline bool pm_resume_via_firmware(void) { return false; }
 340 static inline bool pm_suspend_no_platform(void) { return false; }
 341 static inline bool pm_suspend_default_s2idle(void) { return false; }
 342
 343 static inline void suspend_set_ops(const struct platform_suspend_ops *ops) {}
 344 static inline int pm_suspend(suspend_state_t state) { return -ENOSYS; }
 345 static inline bool idle_should_enter_s2idle(void) { return false; }
 346 static inline void __init pm_states_init(void) {}
 347 static inline void s2idle_set_ops(const struct platform_s2idle_ops *ops) {}
 348 static inline void s2idle_wake(void) {}
 349 #endif /* !CONFIG_SUSPEND */
 350
 351 /* struct pbe is used for creating lists of pages that should be restored
 352  * atomically during the resume from disk, because the page frames they have
 353  * occupied before the suspend are in use.
 354  */
 355 struct pbe {
 356         void *address;          /* address of the copy */
 357         void *orig_address;     /* original address of a page */
 358         struct pbe *next;
 359 };
 360
 361 /* mm/page_alloc.c */
 362 extern void mark_free_pages(struct zone *zone);
 363
 364 /**
 365  * struct platform_hibernation_ops - hibernation platform support
 366  *
 367  * The methods in this structure allow a platform to carry out special
 368  * operations required by it during a hibernation transition.
 369  *
 370  * All the methods below, except for @recover(), must be implemented.
 371  *
 372  * @begin: Tell the platform driver that we're starting hibernation.
 373  *      Called right after shrinking memory and before freezing devices.
 374  *
 375  * @end: Called by the PM core right after resuming devices, to indicate to
 376  *      the platform that the system has returned to the working state.
 377  *
 378  * @pre_snapshot: Prepare the platform for creating the hibernation image.
 379  *      Called right after devices have been frozen and before the nonboot
 380  *      CPUs are disabled (runs with IRQs on).
 381  *
 382  * @finish: Restore the previous state of the platform after the hibernation
 383  *      image has been created *or* put the platform into the normal operation
 384  *      mode after the hibernation (the same method is executed in both cases).
 385  *      Called right after the nonboot CPUs have been enabled and before
 386  *      thawing devices (runs with IRQs on).
 387  *
 388  * @prepare: Prepare the platform for entering the low power state.
 389  *      Called right after the hibernation image has been saved and before
 390  *      devices are prepared for entering the low power state.
 391  *
 392  * @enter: Put the system into the low power state after the hibernation image
 393  *      has been saved to disk.
 394  *      Called after the nonboot CPUs have been disabled and all of the low
 395  *      level devices have been shut down (runs with IRQs off).
 396  *
 397  * @leave: Perform the first stage of the cleanup after the system sleep state
 398  *      indicated by @set_target() has been left.
 399  *      Called right after the control has been passed from the boot kernel to
 400  *      the image kernel, before the nonboot CPUs are enabled and before devices
 401  *      are resumed.  Executed with interrupts disabled.
 402  *
 403  * @pre_restore: Prepare system for the restoration from a hibernation image.
 404  *      Called right after devices have been frozen and before the nonboot
 405  *      CPUs are disabled (runs with IRQs on).
 406  *
 407  * @restore_cleanup: Clean up after a failing image restoration.
 408  *      Called right after the nonboot CPUs have been enabled and before
 409  *      thawing devices (runs with IRQs on).
 410  *
 411  * @recover: Recover the platform from a failure to suspend devices.
 412  *      Called by the PM core if the suspending of devices during hibernation
 413  *      fails.  This callback is optional and should only be implemented by
 414  *      platforms which require special recovery actions in that situation.
 415  */
 416 struct platform_hibernation_ops {
 417         int (*begin)(pm_message_t stage);
 418         void (*end)(void);
 419         int (*pre_snapshot)(void);
 420         void (*finish)(void);
 421         int (*prepare)(void);
 422         int (*enter)(void);
 423         void (*leave)(void);
 424         int (*pre_restore)(void);
 425         void (*restore_cleanup)(void);
 426         void (*recover)(void);
 427 };
 428
 429 #ifdef CONFIG_HIBERNATION
 430 /* kernel/power/snapshot.c */
 431 extern void __register_nosave_region(unsigned long b, unsigned long e, int km);
 432 static inline void __init register_nosave_region(unsigned long b, unsigned long e)
 433 {
 434         __register_nosave_region(b, e, 0);
 435 }
 436 static inline void __init register_nosave_region_late(unsigned long b, unsigned long e)
 437 {
 438         __register_nosave_region(b, e, 1);
 439 }
 440 extern int swsusp_page_is_forbidden(struct page *);
 441 extern void swsusp_set_page_free(struct page *);
 442 extern void swsusp_unset_page_free(struct page *);
 443 extern unsigned long get_safe_page(gfp_t gfp_mask);
 444 extern asmlinkage int swsusp_arch_suspend(void);
 445 extern asmlinkage int swsusp_arch_resume(void);
 446
 447 extern void hibernation_set_ops(const struct platform_hibernation_ops *ops);
 448 extern int hibernate(void);
 449 extern bool system_entering_hibernation(void);
 450 extern bool hibernation_available(void);
 451 asmlinkage int swsusp_save(void);
 452 extern struct pbe *restore_pblist;
 453 int pfn_is_nosave(unsigned long pfn);
 454 #else /* CONFIG_HIBERNATION */
 455 static inline void register_nosave_region(unsigned long b, unsigned long e) {}
 456 static inline void register_nosave_region_late(unsigned long b, unsigned long e) {}
 457 static inline int swsusp_page_is_forbidden(struct page *p) { return 0; }
 458 static inline void swsusp_set_page_free(struct page *p) {}
 459 static inline void swsusp_unset_page_free(struct page *p) {}
 460
 461 static inline void hibernation_set_ops(const struct platform_hibernation_ops *ops) {}
 462 static inline int hibernate(void) { return -ENOSYS; }
 463 static inline bool system_entering_hibernation(void) { return false; }
 464 static inline bool hibernation_available(void) { return false; }
 465 #endif /* CONFIG_HIBERNATION */
 466
 467 /* Hibernation and suspend events */
 468 #define PM_HIBERNATION_PREPARE  0x0001 /* Going to hibernate */
 469 #define PM_POST_HIBERNATION     0x0002 /* Hibernation finished */
 470 #define PM_SUSPEND_PREPARE      0x0003 /* Going to suspend the system */
 471 #define PM_POST_SUSPEND         0x0004 /* Suspend finished */
 472 #define PM_RESTORE_PREPARE      0x0005 /* Going to restore a saved image */
 473 #define PM_POST_RESTORE         0x0006 /* Restore failed */
 474
 475 extern struct mutex system_transition_mutex;
 476
 477 #ifdef CONFIG_PM_SLEEP
 478 void save_processor_state(void);
 479 void restore_processor_state(void);
 480
 481 /* kernel/power/main.c */
 482 extern int register_pm_notifier(struct notifier_block *nb);
 483 extern int unregister_pm_notifier(struct notifier_block *nb);
 484 extern void ksys_sync_helper(void);
 485
 486 #define pm_notifier(fn, pri) {                          \
 487         static struct notifier_block fn##_nb =                  \
 488                 { .notifier_call = fn, .priority = pri };       \
 489         register_pm_notifier(&fn##_nb);                 \
 490 }
 491
 492 /* drivers/base/power/wakeup.c */
 493 extern bool events_check_enabled;
 494 extern unsigned int pm_wakeup_irq;
 495 extern suspend_state_t pm_suspend_target_state;
 496
 497 extern bool pm_wakeup_pending(void);
 498 extern void pm_system_wakeup(void);
 499 extern void pm_system_cancel_wakeup(void);
 500 extern void pm_wakeup_clear(bool reset);
 501 extern void pm_system_irq_wakeup(unsigned int irq_number);
 502 extern bool pm_get_wakeup_count(unsigned int *count, bool block);
 503 extern bool pm_save_wakeup_count(unsigned int count);
 504 extern void pm_wakep_autosleep_enabled(bool set);
 505 extern void pm_print_active_wakeup_sources(void);
 506
 507 extern void lock_system_sleep(void);
 508 extern void unlock_system_sleep(void);
 509
 510 #else /* !CONFIG_PM_SLEEP */
 511
 512 static inline int register_pm_notifier(struct notifier_block *nb)
 513 {
 514         return 0;
 515 }
 516
 517 static inline int unregister_pm_notifier(struct notifier_block *nb)
 518 {
 519         return 0;
 520 }
 521
 522 static inline void ksys_sync_helper(void) {}
 523
 524 #define pm_notifier(fn, pri)    do { (void)(fn); } while (0)
 525
 526 static inline bool pm_wakeup_pending(void) { return false; }
 527 static inline void pm_system_wakeup(void) {}
 528 static inline void pm_wakeup_clear(bool reset) {}
 529 static inline void pm_system_irq_wakeup(unsigned int irq_number) {}
 530
 531 static inline void lock_system_sleep(void) {}
 532 static inline void unlock_system_sleep(void) {}
 533
 534 #endif /* !CONFIG_PM_SLEEP */
 535
 536 #ifdef CONFIG_PM_SLEEP_DEBUG
 537 extern bool pm_print_times_enabled;
 538 extern bool pm_debug_messages_on;
 539 extern __printf(2, 3) void __pm_pr_dbg(bool defer, const char *fmt, ...);
 540 #else
 541 #define pm_print_times_enabled  (false)
 542 #define pm_debug_messages_on    (false)
 543
 544 #include <linux/printk.h>
 545
 546 #define __pm_pr_dbg(defer, fmt, ...) \
 547         no_printk(KERN_DEBUG fmt, ##__VA_ARGS__)
 548 #endif
 549
 550 #define pm_pr_dbg(fmt, ...) \
 551         __pm_pr_dbg(false, fmt, ##__VA_ARGS__)
 552
 553 #define pm_deferred_pr_dbg(fmt, ...) \
 554         __pm_pr_dbg(true, fmt, ##__VA_ARGS__)
 555
 556 #ifdef CONFIG_PM_AUTOSLEEP
 557
 558 /* kernel/power/autosleep.c */
 559 void queue_up_suspend_work(void);
 560
 561 #else /* !CONFIG_PM_AUTOSLEEP */
 562
 563 static inline void queue_up_suspend_work(void) {}
 564
 565 #endif /* !CONFIG_PM_AUTOSLEEP */
 566
 567 #ifdef CONFIG_ARCH_SAVE_PAGE_KEYS
 568 /*
 569  * The ARCH_SAVE_PAGE_KEYS functions can be used by an architecture
 570  * to save/restore additional information to/from the array of page
 571  * frame numbers in the hibernation image. For s390 this is used to
 572  * save and restore the storage key for each page that is included
 573  * in the hibernation image.
 574  */
 575 unsigned long page_key_additional_pages(unsigned long pages);
 576 int page_key_alloc(unsigned long pages);
 577 void page_key_free(void);
 578 void page_key_read(unsigned long *pfn);
 579 void page_key_memorize(unsigned long *pfn);
 580 void page_key_write(void *address);
 581
 582 #else /* !CONFIG_ARCH_SAVE_PAGE_KEYS */
 583
 584 static inline unsigned long page_key_additional_pages(unsigned long pages)
 585 {
 586         return 0;
 587 }
 588
 589 static inline int  page_key_alloc(unsigned long pages)
 590 {
 591         return 0;
 592 }
 593
 594 static inline void page_key_free(void) {}
 595 static inline void page_key_read(unsigned long *pfn) {}
 596 static inline void page_key_memorize(unsigned long *pfn) {}
 597 static inline void page_key_write(void *address) {}
 598
 599 #endif /* !CONFIG_ARCH_SAVE_PAGE_KEYS */
 600
 601 #endif /* _LINUX_SUSPEND_H */