2 * linux/kernel/time/timekeeping.c
4 * Kernel timekeeping code and accessor functions
6 * This code was moved from linux/kernel/timer.c.
7 * Please see that file for copyright and history logs.
11 #include <linux/timekeeper_internal.h>
12 #include <linux/module.h>
13 #include <linux/interrupt.h>
14 #include <linux/percpu.h>
15 #include <linux/init.h>
17 #include <linux/sched.h>
18 #include <linux/syscore_ops.h>
19 #include <linux/clocksource.h>
20 #include <linux/jiffies.h>
21 #include <linux/time.h>
22 #include <linux/tick.h>
23 #include <linux/stop_machine.h>
24 #include <linux/pvclock_gtod.h>
25 #include <linux/compiler.h>
27 #include "tick-internal.h"
28 #include "ntp_internal.h"
29 #include "timekeeping_internal.h"
31 #define TK_CLEAR_NTP (1 << 0)
32 #define TK_MIRROR (1 << 1)
33 #define TK_CLOCK_WAS_SET (1 << 2)
36 * The most important data for readout fits into a single 64 byte
41 struct timekeeper timekeeper
;
42 } tk_core ____cacheline_aligned
;
44 static DEFINE_RAW_SPINLOCK(timekeeper_lock
);
45 static struct timekeeper shadow_timekeeper
;
47 /* flag for if timekeeping is suspended */
48 int __read_mostly timekeeping_suspended
;
50 /* Flag for if there is a persistent clock on this platform */
51 bool __read_mostly persistent_clock_exist
= false;
53 static inline void tk_normalize_xtime(struct timekeeper
*tk
)
55 while (tk
->xtime_nsec
>= ((u64
)NSEC_PER_SEC
<< tk
->shift
)) {
56 tk
->xtime_nsec
-= (u64
)NSEC_PER_SEC
<< tk
->shift
;
61 static inline struct timespec64
tk_xtime(struct timekeeper
*tk
)
65 ts
.tv_sec
= tk
->xtime_sec
;
66 ts
.tv_nsec
= (long)(tk
->xtime_nsec
>> tk
->shift
);
70 static void tk_set_xtime(struct timekeeper
*tk
, const struct timespec64
*ts
)
72 tk
->xtime_sec
= ts
->tv_sec
;
73 tk
->xtime_nsec
= (u64
)ts
->tv_nsec
<< tk
->shift
;
76 static void tk_xtime_add(struct timekeeper
*tk
, const struct timespec64
*ts
)
78 tk
->xtime_sec
+= ts
->tv_sec
;
79 tk
->xtime_nsec
+= (u64
)ts
->tv_nsec
<< tk
->shift
;
80 tk_normalize_xtime(tk
);
83 static void tk_set_wall_to_mono(struct timekeeper
*tk
, struct timespec64 wtm
)
85 struct timespec64 tmp
;
88 * Verify consistency of: offset_real = -wall_to_monotonic
89 * before modifying anything
91 set_normalized_timespec64(&tmp
, -tk
->wall_to_monotonic
.tv_sec
,
92 -tk
->wall_to_monotonic
.tv_nsec
);
93 WARN_ON_ONCE(tk
->offs_real
.tv64
!= timespec64_to_ktime(tmp
).tv64
);
94 tk
->wall_to_monotonic
= wtm
;
95 set_normalized_timespec64(&tmp
, -wtm
.tv_sec
, -wtm
.tv_nsec
);
96 tk
->offs_real
= timespec64_to_ktime(tmp
);
97 tk
->offs_tai
= ktime_add(tk
->offs_real
, ktime_set(tk
->tai_offset
, 0));
100 static void tk_set_sleep_time(struct timekeeper
*tk
, struct timespec64 t
)
102 /* Verify consistency before modifying */
103 WARN_ON_ONCE(tk
->offs_boot
.tv64
!= timespec64_to_ktime(tk
->total_sleep_time
).tv64
);
105 tk
->total_sleep_time
= t
;
106 tk
->offs_boot
= timespec64_to_ktime(t
);
110 * tk_setup_internals - Set up internals to use clocksource clock.
112 * @tk: The target timekeeper to setup.
113 * @clock: Pointer to clocksource.
115 * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
116 * pair and interval request.
118 * Unless you're the timekeeping code, you should not be using this!
120 static void tk_setup_internals(struct timekeeper
*tk
, struct clocksource
*clock
)
123 u64 tmp
, ntpinterval
;
124 struct clocksource
*old_clock
;
126 old_clock
= tk
->clock
;
128 tk
->cycle_last
= clock
->cycle_last
= clock
->read(clock
);
130 /* Do the ns -> cycle conversion first, using original mult */
131 tmp
= NTP_INTERVAL_LENGTH
;
132 tmp
<<= clock
->shift
;
134 tmp
+= clock
->mult
/2;
135 do_div(tmp
, clock
->mult
);
139 interval
= (cycle_t
) tmp
;
140 tk
->cycle_interval
= interval
;
142 /* Go back from cycles -> shifted ns */
143 tk
->xtime_interval
= (u64
) interval
* clock
->mult
;
144 tk
->xtime_remainder
= ntpinterval
- tk
->xtime_interval
;
146 ((u64
) interval
* clock
->mult
) >> clock
->shift
;
148 /* if changing clocks, convert xtime_nsec shift units */
150 int shift_change
= clock
->shift
- old_clock
->shift
;
151 if (shift_change
< 0)
152 tk
->xtime_nsec
>>= -shift_change
;
154 tk
->xtime_nsec
<<= shift_change
;
156 tk
->shift
= clock
->shift
;
159 tk
->ntp_error_shift
= NTP_SCALE_SHIFT
- clock
->shift
;
162 * The timekeeper keeps its own mult values for the currently
163 * active clocksource. These value will be adjusted via NTP
164 * to counteract clock drifting.
166 tk
->mult
= clock
->mult
;
169 /* Timekeeper helper functions. */
171 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
172 static u32
default_arch_gettimeoffset(void) { return 0; }
173 u32 (*arch_gettimeoffset
)(void) = default_arch_gettimeoffset
;
175 static inline u32
arch_gettimeoffset(void) { return 0; }
178 static inline s64
timekeeping_get_ns(struct timekeeper
*tk
)
180 cycle_t cycle_now
, cycle_delta
;
181 struct clocksource
*clock
;
184 /* read clocksource: */
186 cycle_now
= clock
->read(clock
);
188 /* calculate the delta since the last update_wall_time: */
189 cycle_delta
= (cycle_now
- clock
->cycle_last
) & clock
->mask
;
191 nsec
= cycle_delta
* tk
->mult
+ tk
->xtime_nsec
;
194 /* If arch requires, add in get_arch_timeoffset() */
195 return nsec
+ arch_gettimeoffset();
198 static inline s64
timekeeping_get_ns_raw(struct timekeeper
*tk
)
200 cycle_t cycle_now
, cycle_delta
;
201 struct clocksource
*clock
;
204 /* read clocksource: */
206 cycle_now
= clock
->read(clock
);
208 /* calculate the delta since the last update_wall_time: */
209 cycle_delta
= (cycle_now
- clock
->cycle_last
) & clock
->mask
;
211 /* convert delta to nanoseconds. */
212 nsec
= clocksource_cyc2ns(cycle_delta
, clock
->mult
, clock
->shift
);
214 /* If arch requires, add in get_arch_timeoffset() */
215 return nsec
+ arch_gettimeoffset();
218 #ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD
220 static inline void update_vsyscall(struct timekeeper
*tk
)
225 update_vsyscall_old(&xt
, &tk
->wall_to_monotonic
, tk
->clock
, tk
->mult
);
228 static inline void old_vsyscall_fixup(struct timekeeper
*tk
)
233 * Store only full nanoseconds into xtime_nsec after rounding
234 * it up and add the remainder to the error difference.
235 * XXX - This is necessary to avoid small 1ns inconsistnecies caused
236 * by truncating the remainder in vsyscalls. However, it causes
237 * additional work to be done in timekeeping_adjust(). Once
238 * the vsyscall implementations are converted to use xtime_nsec
239 * (shifted nanoseconds), and CONFIG_GENERIC_TIME_VSYSCALL_OLD
240 * users are removed, this can be killed.
242 remainder
= tk
->xtime_nsec
& ((1ULL << tk
->shift
) - 1);
243 tk
->xtime_nsec
-= remainder
;
244 tk
->xtime_nsec
+= 1ULL << tk
->shift
;
245 tk
->ntp_error
+= remainder
<< tk
->ntp_error_shift
;
246 tk
->ntp_error
-= (1ULL << tk
->shift
) << tk
->ntp_error_shift
;
249 #define old_vsyscall_fixup(tk)
252 static RAW_NOTIFIER_HEAD(pvclock_gtod_chain
);
254 static void update_pvclock_gtod(struct timekeeper
*tk
, bool was_set
)
256 raw_notifier_call_chain(&pvclock_gtod_chain
, was_set
, tk
);
260 * pvclock_gtod_register_notifier - register a pvclock timedata update listener
262 int pvclock_gtod_register_notifier(struct notifier_block
*nb
)
264 struct timekeeper
*tk
= &tk_core
.timekeeper
;
268 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
269 ret
= raw_notifier_chain_register(&pvclock_gtod_chain
, nb
);
270 update_pvclock_gtod(tk
, true);
271 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
275 EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier
);
278 * pvclock_gtod_unregister_notifier - unregister a pvclock
279 * timedata update listener
281 int pvclock_gtod_unregister_notifier(struct notifier_block
*nb
)
286 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
287 ret
= raw_notifier_chain_unregister(&pvclock_gtod_chain
, nb
);
288 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
292 EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier
);
295 * Update the ktime_t based scalar nsec members of the timekeeper
297 static inline void tk_update_ktime_data(struct timekeeper
*tk
)
302 * The xtime based monotonic readout is:
303 * nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();
304 * The ktime based monotonic readout is:
305 * nsec = base_mono + now();
306 * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec
308 nsec
= (s64
)(tk
->xtime_sec
+ tk
->wall_to_monotonic
.tv_sec
);
309 nsec
*= NSEC_PER_SEC
;
310 nsec
+= tk
->wall_to_monotonic
.tv_nsec
;
311 tk
->base_mono
= ns_to_ktime(nsec
);
314 /* must hold timekeeper_lock */
315 static void timekeeping_update(struct timekeeper
*tk
, unsigned int action
)
317 if (action
& TK_CLEAR_NTP
) {
322 update_pvclock_gtod(tk
, action
& TK_CLOCK_WAS_SET
);
324 tk_update_ktime_data(tk
);
326 if (action
& TK_MIRROR
)
327 memcpy(&shadow_timekeeper
, &tk_core
.timekeeper
,
328 sizeof(tk_core
.timekeeper
));
332 * timekeeping_forward_now - update clock to the current time
334 * Forward the current clock to update its state since the last call to
335 * update_wall_time(). This is useful before significant clock changes,
336 * as it avoids having to deal with this time offset explicitly.
338 static void timekeeping_forward_now(struct timekeeper
*tk
)
340 cycle_t cycle_now
, cycle_delta
;
341 struct clocksource
*clock
;
345 cycle_now
= clock
->read(clock
);
346 cycle_delta
= (cycle_now
- clock
->cycle_last
) & clock
->mask
;
347 tk
->cycle_last
= clock
->cycle_last
= cycle_now
;
349 tk
->xtime_nsec
+= cycle_delta
* tk
->mult
;
351 /* If arch requires, add in get_arch_timeoffset() */
352 tk
->xtime_nsec
+= (u64
)arch_gettimeoffset() << tk
->shift
;
354 tk_normalize_xtime(tk
);
356 nsec
= clocksource_cyc2ns(cycle_delta
, clock
->mult
, clock
->shift
);
357 timespec64_add_ns(&tk
->raw_time
, nsec
);
361 * __getnstimeofday64 - Returns the time of day in a timespec64.
362 * @ts: pointer to the timespec to be set
364 * Updates the time of day in the timespec.
365 * Returns 0 on success, or -ve when suspended (timespec will be undefined).
367 int __getnstimeofday64(struct timespec64
*ts
)
369 struct timekeeper
*tk
= &tk_core
.timekeeper
;
374 seq
= read_seqcount_begin(&tk_core
.seq
);
376 ts
->tv_sec
= tk
->xtime_sec
;
377 nsecs
= timekeeping_get_ns(tk
);
379 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
382 timespec64_add_ns(ts
, nsecs
);
385 * Do not bail out early, in case there were callers still using
386 * the value, even in the face of the WARN_ON.
388 if (unlikely(timekeeping_suspended
))
392 EXPORT_SYMBOL(__getnstimeofday64
);
395 * getnstimeofday64 - Returns the time of day in a timespec64.
396 * @ts: pointer to the timespec to be set
398 * Returns the time of day in a timespec (WARN if suspended).
400 void getnstimeofday64(struct timespec64
*ts
)
402 WARN_ON(__getnstimeofday64(ts
));
404 EXPORT_SYMBOL(getnstimeofday64
);
406 ktime_t
ktime_get(void)
408 struct timekeeper
*tk
= &tk_core
.timekeeper
;
413 WARN_ON(timekeeping_suspended
);
416 seq
= read_seqcount_begin(&tk_core
.seq
);
417 base
= tk
->base_mono
;
418 nsecs
= timekeeping_get_ns(tk
);
420 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
422 return ktime_add_ns(base
, nsecs
);
424 EXPORT_SYMBOL_GPL(ktime_get
);
426 static ktime_t
*offsets
[TK_OFFS_MAX
] = {
427 [TK_OFFS_REAL
] = &tk_core
.timekeeper
.offs_real
,
428 [TK_OFFS_BOOT
] = &tk_core
.timekeeper
.offs_boot
,
429 [TK_OFFS_TAI
] = &tk_core
.timekeeper
.offs_tai
,
432 ktime_t
ktime_get_with_offset(enum tk_offsets offs
)
434 struct timekeeper
*tk
= &tk_core
.timekeeper
;
436 ktime_t base
, *offset
= offsets
[offs
];
439 WARN_ON(timekeeping_suspended
);
442 seq
= read_seqcount_begin(&tk_core
.seq
);
443 base
= ktime_add(tk
->base_mono
, *offset
);
444 nsecs
= timekeeping_get_ns(tk
);
446 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
448 return ktime_add_ns(base
, nsecs
);
451 EXPORT_SYMBOL_GPL(ktime_get_with_offset
);
454 * ktime_get_ts64 - get the monotonic clock in timespec64 format
455 * @ts: pointer to timespec variable
457 * The function calculates the monotonic clock from the realtime
458 * clock and the wall_to_monotonic offset and stores the result
459 * in normalized timespec format in the variable pointed to by @ts.
461 void ktime_get_ts64(struct timespec64
*ts
)
463 struct timekeeper
*tk
= &tk_core
.timekeeper
;
464 struct timespec64 tomono
;
468 WARN_ON(timekeeping_suspended
);
471 seq
= read_seqcount_begin(&tk_core
.seq
);
472 ts
->tv_sec
= tk
->xtime_sec
;
473 nsec
= timekeeping_get_ns(tk
);
474 tomono
= tk
->wall_to_monotonic
;
476 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
478 ts
->tv_sec
+= tomono
.tv_sec
;
480 timespec64_add_ns(ts
, nsec
+ tomono
.tv_nsec
);
482 EXPORT_SYMBOL_GPL(ktime_get_ts64
);
486 * timekeeping_clocktai - Returns the TAI time of day in a timespec
487 * @ts: pointer to the timespec to be set
489 * Returns the time of day in a timespec.
491 void timekeeping_clocktai(struct timespec
*ts
)
493 struct timekeeper
*tk
= &tk_core
.timekeeper
;
494 struct timespec64 ts64
;
498 WARN_ON(timekeeping_suspended
);
501 seq
= read_seqcount_begin(&tk_core
.seq
);
503 ts64
.tv_sec
= tk
->xtime_sec
+ tk
->tai_offset
;
504 nsecs
= timekeeping_get_ns(tk
);
506 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
509 timespec64_add_ns(&ts64
, nsecs
);
510 *ts
= timespec64_to_timespec(ts64
);
513 EXPORT_SYMBOL(timekeeping_clocktai
);
517 * ktime_get_clocktai - Returns the TAI time of day in a ktime
519 * Returns the time of day in a ktime.
521 ktime_t
ktime_get_clocktai(void)
525 timekeeping_clocktai(&ts
);
526 return timespec_to_ktime(ts
);
528 EXPORT_SYMBOL(ktime_get_clocktai
);
530 #ifdef CONFIG_NTP_PPS
533 * getnstime_raw_and_real - get day and raw monotonic time in timespec format
534 * @ts_raw: pointer to the timespec to be set to raw monotonic time
535 * @ts_real: pointer to the timespec to be set to the time of day
537 * This function reads both the time of day and raw monotonic time at the
538 * same time atomically and stores the resulting timestamps in timespec
541 void getnstime_raw_and_real(struct timespec
*ts_raw
, struct timespec
*ts_real
)
543 struct timekeeper
*tk
= &tk_core
.timekeeper
;
545 s64 nsecs_raw
, nsecs_real
;
547 WARN_ON_ONCE(timekeeping_suspended
);
550 seq
= read_seqcount_begin(&tk_core
.seq
);
552 *ts_raw
= timespec64_to_timespec(tk
->raw_time
);
553 ts_real
->tv_sec
= tk
->xtime_sec
;
554 ts_real
->tv_nsec
= 0;
556 nsecs_raw
= timekeeping_get_ns_raw(tk
);
557 nsecs_real
= timekeeping_get_ns(tk
);
559 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
561 timespec_add_ns(ts_raw
, nsecs_raw
);
562 timespec_add_ns(ts_real
, nsecs_real
);
564 EXPORT_SYMBOL(getnstime_raw_and_real
);
566 #endif /* CONFIG_NTP_PPS */
569 * do_gettimeofday - Returns the time of day in a timeval
570 * @tv: pointer to the timeval to be set
572 * NOTE: Users should be converted to using getnstimeofday()
574 void do_gettimeofday(struct timeval
*tv
)
576 struct timespec64 now
;
578 getnstimeofday64(&now
);
579 tv
->tv_sec
= now
.tv_sec
;
580 tv
->tv_usec
= now
.tv_nsec
/1000;
582 EXPORT_SYMBOL(do_gettimeofday
);
585 * do_settimeofday - Sets the time of day
586 * @tv: pointer to the timespec variable containing the new time
588 * Sets the time of day to the new time and update NTP and notify hrtimers
590 int do_settimeofday(const struct timespec
*tv
)
592 struct timekeeper
*tk
= &tk_core
.timekeeper
;
593 struct timespec64 ts_delta
, xt
, tmp
;
596 if (!timespec_valid_strict(tv
))
599 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
600 write_seqcount_begin(&tk_core
.seq
);
602 timekeeping_forward_now(tk
);
605 ts_delta
.tv_sec
= tv
->tv_sec
- xt
.tv_sec
;
606 ts_delta
.tv_nsec
= tv
->tv_nsec
- xt
.tv_nsec
;
608 tk_set_wall_to_mono(tk
, timespec64_sub(tk
->wall_to_monotonic
, ts_delta
));
610 tmp
= timespec_to_timespec64(*tv
);
611 tk_set_xtime(tk
, &tmp
);
613 timekeeping_update(tk
, TK_CLEAR_NTP
| TK_MIRROR
| TK_CLOCK_WAS_SET
);
615 write_seqcount_end(&tk_core
.seq
);
616 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
618 /* signal hrtimers about time change */
623 EXPORT_SYMBOL(do_settimeofday
);
626 * timekeeping_inject_offset - Adds or subtracts from the current time.
627 * @tv: pointer to the timespec variable containing the offset
629 * Adds or subtracts an offset value from the current time.
631 int timekeeping_inject_offset(struct timespec
*ts
)
633 struct timekeeper
*tk
= &tk_core
.timekeeper
;
635 struct timespec64 ts64
, tmp
;
638 if ((unsigned long)ts
->tv_nsec
>= NSEC_PER_SEC
)
641 ts64
= timespec_to_timespec64(*ts
);
643 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
644 write_seqcount_begin(&tk_core
.seq
);
646 timekeeping_forward_now(tk
);
648 /* Make sure the proposed value is valid */
649 tmp
= timespec64_add(tk_xtime(tk
), ts64
);
650 if (!timespec64_valid_strict(&tmp
)) {
655 tk_xtime_add(tk
, &ts64
);
656 tk_set_wall_to_mono(tk
, timespec64_sub(tk
->wall_to_monotonic
, ts64
));
658 error
: /* even if we error out, we forwarded the time, so call update */
659 timekeeping_update(tk
, TK_CLEAR_NTP
| TK_MIRROR
| TK_CLOCK_WAS_SET
);
661 write_seqcount_end(&tk_core
.seq
);
662 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
664 /* signal hrtimers about time change */
669 EXPORT_SYMBOL(timekeeping_inject_offset
);
673 * timekeeping_get_tai_offset - Returns current TAI offset from UTC
676 s32
timekeeping_get_tai_offset(void)
678 struct timekeeper
*tk
= &tk_core
.timekeeper
;
683 seq
= read_seqcount_begin(&tk_core
.seq
);
684 ret
= tk
->tai_offset
;
685 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
691 * __timekeeping_set_tai_offset - Lock free worker function
694 static void __timekeeping_set_tai_offset(struct timekeeper
*tk
, s32 tai_offset
)
696 tk
->tai_offset
= tai_offset
;
697 tk
->offs_tai
= ktime_add(tk
->offs_real
, ktime_set(tai_offset
, 0));
701 * timekeeping_set_tai_offset - Sets the current TAI offset from UTC
704 void timekeeping_set_tai_offset(s32 tai_offset
)
706 struct timekeeper
*tk
= &tk_core
.timekeeper
;
709 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
710 write_seqcount_begin(&tk_core
.seq
);
711 __timekeeping_set_tai_offset(tk
, tai_offset
);
712 timekeeping_update(tk
, TK_MIRROR
| TK_CLOCK_WAS_SET
);
713 write_seqcount_end(&tk_core
.seq
);
714 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
719 * change_clocksource - Swaps clocksources if a new one is available
721 * Accumulates current time interval and initializes new clocksource
723 static int change_clocksource(void *data
)
725 struct timekeeper
*tk
= &tk_core
.timekeeper
;
726 struct clocksource
*new, *old
;
729 new = (struct clocksource
*) data
;
731 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
732 write_seqcount_begin(&tk_core
.seq
);
734 timekeeping_forward_now(tk
);
736 * If the cs is in module, get a module reference. Succeeds
737 * for built-in code (owner == NULL) as well.
739 if (try_module_get(new->owner
)) {
740 if (!new->enable
|| new->enable(new) == 0) {
742 tk_setup_internals(tk
, new);
745 module_put(old
->owner
);
747 module_put(new->owner
);
750 timekeeping_update(tk
, TK_CLEAR_NTP
| TK_MIRROR
| TK_CLOCK_WAS_SET
);
752 write_seqcount_end(&tk_core
.seq
);
753 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
759 * timekeeping_notify - Install a new clock source
760 * @clock: pointer to the clock source
762 * This function is called from clocksource.c after a new, better clock
763 * source has been registered. The caller holds the clocksource_mutex.
765 int timekeeping_notify(struct clocksource
*clock
)
767 struct timekeeper
*tk
= &tk_core
.timekeeper
;
769 if (tk
->clock
== clock
)
771 stop_machine(change_clocksource
, clock
, NULL
);
773 return tk
->clock
== clock
? 0 : -1;
777 * getrawmonotonic - Returns the raw monotonic time in a timespec
778 * @ts: pointer to the timespec to be set
780 * Returns the raw monotonic time (completely un-modified by ntp)
782 void getrawmonotonic(struct timespec
*ts
)
784 struct timekeeper
*tk
= &tk_core
.timekeeper
;
785 struct timespec64 ts64
;
790 seq
= read_seqcount_begin(&tk_core
.seq
);
791 nsecs
= timekeeping_get_ns_raw(tk
);
794 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
796 timespec64_add_ns(&ts64
, nsecs
);
797 *ts
= timespec64_to_timespec(ts64
);
799 EXPORT_SYMBOL(getrawmonotonic
);
802 * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
804 int timekeeping_valid_for_hres(void)
806 struct timekeeper
*tk
= &tk_core
.timekeeper
;
811 seq
= read_seqcount_begin(&tk_core
.seq
);
813 ret
= tk
->clock
->flags
& CLOCK_SOURCE_VALID_FOR_HRES
;
815 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
821 * timekeeping_max_deferment - Returns max time the clocksource can be deferred
823 u64
timekeeping_max_deferment(void)
825 struct timekeeper
*tk
= &tk_core
.timekeeper
;
830 seq
= read_seqcount_begin(&tk_core
.seq
);
832 ret
= tk
->clock
->max_idle_ns
;
834 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
840 * read_persistent_clock - Return time from the persistent clock.
842 * Weak dummy function for arches that do not yet support it.
843 * Reads the time from the battery backed persistent clock.
844 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
846 * XXX - Do be sure to remove it once all arches implement it.
848 void __weak
read_persistent_clock(struct timespec
*ts
)
855 * read_boot_clock - Return time of the system start.
857 * Weak dummy function for arches that do not yet support it.
858 * Function to read the exact time the system has been started.
859 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
861 * XXX - Do be sure to remove it once all arches implement it.
863 void __weak
read_boot_clock(struct timespec
*ts
)
870 * timekeeping_init - Initializes the clocksource and common timekeeping values
872 void __init
timekeeping_init(void)
874 struct timekeeper
*tk
= &tk_core
.timekeeper
;
875 struct clocksource
*clock
;
877 struct timespec64 now
, boot
, tmp
;
880 read_persistent_clock(&ts
);
881 now
= timespec_to_timespec64(ts
);
882 if (!timespec64_valid_strict(&now
)) {
883 pr_warn("WARNING: Persistent clock returned invalid value!\n"
884 " Check your CMOS/BIOS settings.\n");
887 } else if (now
.tv_sec
|| now
.tv_nsec
)
888 persistent_clock_exist
= true;
890 read_boot_clock(&ts
);
891 boot
= timespec_to_timespec64(ts
);
892 if (!timespec64_valid_strict(&boot
)) {
893 pr_warn("WARNING: Boot clock returned invalid value!\n"
894 " Check your CMOS/BIOS settings.\n");
899 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
900 write_seqcount_begin(&tk_core
.seq
);
903 clock
= clocksource_default_clock();
905 clock
->enable(clock
);
906 tk_setup_internals(tk
, clock
);
908 tk_set_xtime(tk
, &now
);
909 tk
->raw_time
.tv_sec
= 0;
910 tk
->raw_time
.tv_nsec
= 0;
911 if (boot
.tv_sec
== 0 && boot
.tv_nsec
== 0)
914 set_normalized_timespec64(&tmp
, -boot
.tv_sec
, -boot
.tv_nsec
);
915 tk_set_wall_to_mono(tk
, tmp
);
919 tk_set_sleep_time(tk
, tmp
);
921 timekeeping_update(tk
, TK_MIRROR
);
923 write_seqcount_end(&tk_core
.seq
);
924 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
927 /* time in seconds when suspend began */
928 static struct timespec64 timekeeping_suspend_time
;
931 * __timekeeping_inject_sleeptime - Internal function to add sleep interval
932 * @delta: pointer to a timespec delta value
934 * Takes a timespec offset measuring a suspend interval and properly
935 * adds the sleep offset to the timekeeping variables.
937 static void __timekeeping_inject_sleeptime(struct timekeeper
*tk
,
938 struct timespec64
*delta
)
940 if (!timespec64_valid_strict(delta
)) {
941 printk_deferred(KERN_WARNING
942 "__timekeeping_inject_sleeptime: Invalid "
943 "sleep delta value!\n");
946 tk_xtime_add(tk
, delta
);
947 tk_set_wall_to_mono(tk
, timespec64_sub(tk
->wall_to_monotonic
, *delta
));
948 tk_set_sleep_time(tk
, timespec64_add(tk
->total_sleep_time
, *delta
));
949 tk_debug_account_sleep_time(delta
);
953 * timekeeping_inject_sleeptime - Adds suspend interval to timeekeeping values
954 * @delta: pointer to a timespec delta value
956 * This hook is for architectures that cannot support read_persistent_clock
957 * because their RTC/persistent clock is only accessible when irqs are enabled.
959 * This function should only be called by rtc_resume(), and allows
960 * a suspend offset to be injected into the timekeeping values.
962 void timekeeping_inject_sleeptime(struct timespec
*delta
)
964 struct timekeeper
*tk
= &tk_core
.timekeeper
;
965 struct timespec64 tmp
;
969 * Make sure we don't set the clock twice, as timekeeping_resume()
972 if (has_persistent_clock())
975 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
976 write_seqcount_begin(&tk_core
.seq
);
978 timekeeping_forward_now(tk
);
980 tmp
= timespec_to_timespec64(*delta
);
981 __timekeeping_inject_sleeptime(tk
, &tmp
);
983 timekeeping_update(tk
, TK_CLEAR_NTP
| TK_MIRROR
| TK_CLOCK_WAS_SET
);
985 write_seqcount_end(&tk_core
.seq
);
986 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
988 /* signal hrtimers about time change */
993 * timekeeping_resume - Resumes the generic timekeeping subsystem.
995 * This is for the generic clocksource timekeeping.
996 * xtime/wall_to_monotonic/jiffies/etc are
997 * still managed by arch specific suspend/resume code.
999 static void timekeeping_resume(void)
1001 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1002 struct clocksource
*clock
= tk
->clock
;
1003 unsigned long flags
;
1004 struct timespec64 ts_new
, ts_delta
;
1005 struct timespec tmp
;
1006 cycle_t cycle_now
, cycle_delta
;
1007 bool suspendtime_found
= false;
1009 read_persistent_clock(&tmp
);
1010 ts_new
= timespec_to_timespec64(tmp
);
1012 clockevents_resume();
1013 clocksource_resume();
1015 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1016 write_seqcount_begin(&tk_core
.seq
);
1019 * After system resumes, we need to calculate the suspended time and
1020 * compensate it for the OS time. There are 3 sources that could be
1021 * used: Nonstop clocksource during suspend, persistent clock and rtc
1024 * One specific platform may have 1 or 2 or all of them, and the
1025 * preference will be:
1026 * suspend-nonstop clocksource -> persistent clock -> rtc
1027 * The less preferred source will only be tried if there is no better
1028 * usable source. The rtc part is handled separately in rtc core code.
1030 cycle_now
= clock
->read(clock
);
1031 if ((clock
->flags
& CLOCK_SOURCE_SUSPEND_NONSTOP
) &&
1032 cycle_now
> clock
->cycle_last
) {
1033 u64 num
, max
= ULLONG_MAX
;
1034 u32 mult
= clock
->mult
;
1035 u32 shift
= clock
->shift
;
1038 cycle_delta
= (cycle_now
- clock
->cycle_last
) & clock
->mask
;
1041 * "cycle_delta * mutl" may cause 64 bits overflow, if the
1042 * suspended time is too long. In that case we need do the
1043 * 64 bits math carefully
1046 if (cycle_delta
> max
) {
1047 num
= div64_u64(cycle_delta
, max
);
1048 nsec
= (((u64
) max
* mult
) >> shift
) * num
;
1049 cycle_delta
-= num
* max
;
1051 nsec
+= ((u64
) cycle_delta
* mult
) >> shift
;
1053 ts_delta
= ns_to_timespec64(nsec
);
1054 suspendtime_found
= true;
1055 } else if (timespec64_compare(&ts_new
, &timekeeping_suspend_time
) > 0) {
1056 ts_delta
= timespec64_sub(ts_new
, timekeeping_suspend_time
);
1057 suspendtime_found
= true;
1060 if (suspendtime_found
)
1061 __timekeeping_inject_sleeptime(tk
, &ts_delta
);
1063 /* Re-base the last cycle value */
1064 tk
->cycle_last
= clock
->cycle_last
= cycle_now
;
1066 timekeeping_suspended
= 0;
1067 timekeeping_update(tk
, TK_MIRROR
| TK_CLOCK_WAS_SET
);
1068 write_seqcount_end(&tk_core
.seq
);
1069 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1071 touch_softlockup_watchdog();
1073 clockevents_notify(CLOCK_EVT_NOTIFY_RESUME
, NULL
);
1075 /* Resume hrtimers */
1079 static int timekeeping_suspend(void)
1081 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1082 unsigned long flags
;
1083 struct timespec64 delta
, delta_delta
;
1084 static struct timespec64 old_delta
;
1085 struct timespec tmp
;
1087 read_persistent_clock(&tmp
);
1088 timekeeping_suspend_time
= timespec_to_timespec64(tmp
);
1091 * On some systems the persistent_clock can not be detected at
1092 * timekeeping_init by its return value, so if we see a valid
1093 * value returned, update the persistent_clock_exists flag.
1095 if (timekeeping_suspend_time
.tv_sec
|| timekeeping_suspend_time
.tv_nsec
)
1096 persistent_clock_exist
= true;
1098 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1099 write_seqcount_begin(&tk_core
.seq
);
1100 timekeeping_forward_now(tk
);
1101 timekeeping_suspended
= 1;
1104 * To avoid drift caused by repeated suspend/resumes,
1105 * which each can add ~1 second drift error,
1106 * try to compensate so the difference in system time
1107 * and persistent_clock time stays close to constant.
1109 delta
= timespec64_sub(tk_xtime(tk
), timekeeping_suspend_time
);
1110 delta_delta
= timespec64_sub(delta
, old_delta
);
1111 if (abs(delta_delta
.tv_sec
) >= 2) {
1113 * if delta_delta is too large, assume time correction
1114 * has occured and set old_delta to the current delta.
1118 /* Otherwise try to adjust old_system to compensate */
1119 timekeeping_suspend_time
=
1120 timespec64_add(timekeeping_suspend_time
, delta_delta
);
1123 timekeeping_update(tk
, TK_MIRROR
);
1124 write_seqcount_end(&tk_core
.seq
);
1125 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1127 clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND
, NULL
);
1128 clocksource_suspend();
1129 clockevents_suspend();
1134 /* sysfs resume/suspend bits for timekeeping */
1135 static struct syscore_ops timekeeping_syscore_ops
= {
1136 .resume
= timekeeping_resume
,
1137 .suspend
= timekeeping_suspend
,
1140 static int __init
timekeeping_init_ops(void)
1142 register_syscore_ops(&timekeeping_syscore_ops
);
1146 device_initcall(timekeeping_init_ops
);
1149 * If the error is already larger, we look ahead even further
1150 * to compensate for late or lost adjustments.
1152 static __always_inline
int timekeeping_bigadjust(struct timekeeper
*tk
,
1153 s64 error
, s64
*interval
,
1157 u32 look_ahead
, adj
;
1161 * Use the current error value to determine how much to look ahead.
1162 * The larger the error the slower we adjust for it to avoid problems
1163 * with losing too many ticks, otherwise we would overadjust and
1164 * produce an even larger error. The smaller the adjustment the
1165 * faster we try to adjust for it, as lost ticks can do less harm
1166 * here. This is tuned so that an error of about 1 msec is adjusted
1167 * within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks).
1169 error2
= tk
->ntp_error
>> (NTP_SCALE_SHIFT
+ 22 - 2 * SHIFT_HZ
);
1170 error2
= abs(error2
);
1171 for (look_ahead
= 0; error2
> 0; look_ahead
++)
1175 * Now calculate the error in (1 << look_ahead) ticks, but first
1176 * remove the single look ahead already included in the error.
1178 tick_error
= ntp_tick_length() >> (tk
->ntp_error_shift
+ 1);
1179 tick_error
-= tk
->xtime_interval
>> 1;
1180 error
= ((error
- tick_error
) >> look_ahead
) + tick_error
;
1182 /* Finally calculate the adjustment shift value. */
1187 *interval
= -*interval
;
1191 for (adj
= 0; error
> i
; adj
++)
1200 * Adjust the multiplier to reduce the error value,
1201 * this is optimized for the most common adjustments of -1,0,1,
1202 * for other values we can do a bit more work.
1204 static void timekeeping_adjust(struct timekeeper
*tk
, s64 offset
)
1206 s64 error
, interval
= tk
->cycle_interval
;
1210 * The point of this is to check if the error is greater than half
1213 * First we shift it down from NTP_SHIFT to clocksource->shifted nsecs.
1215 * Note we subtract one in the shift, so that error is really error*2.
1216 * This "saves" dividing(shifting) interval twice, but keeps the
1217 * (error > interval) comparison as still measuring if error is
1218 * larger than half an interval.
1220 * Note: It does not "save" on aggravation when reading the code.
1222 error
= tk
->ntp_error
>> (tk
->ntp_error_shift
- 1);
1223 if (error
> interval
) {
1225 * We now divide error by 4(via shift), which checks if
1226 * the error is greater than twice the interval.
1227 * If it is greater, we need a bigadjust, if its smaller,
1228 * we can adjust by 1.
1231 if (likely(error
<= interval
))
1234 adj
= timekeeping_bigadjust(tk
, error
, &interval
, &offset
);
1236 if (error
< -interval
) {
1237 /* See comment above, this is just switched for the negative */
1239 if (likely(error
>= -interval
)) {
1241 interval
= -interval
;
1244 adj
= timekeeping_bigadjust(tk
, error
, &interval
, &offset
);
1251 if (unlikely(tk
->clock
->maxadj
&&
1252 (tk
->mult
+ adj
> tk
->clock
->mult
+ tk
->clock
->maxadj
))) {
1253 printk_deferred_once(KERN_WARNING
1254 "Adjusting %s more than 11%% (%ld vs %ld)\n",
1255 tk
->clock
->name
, (long)tk
->mult
+ adj
,
1256 (long)tk
->clock
->mult
+ tk
->clock
->maxadj
);
1259 * So the following can be confusing.
1261 * To keep things simple, lets assume adj == 1 for now.
1263 * When adj != 1, remember that the interval and offset values
1264 * have been appropriately scaled so the math is the same.
1266 * The basic idea here is that we're increasing the multiplier
1267 * by one, this causes the xtime_interval to be incremented by
1268 * one cycle_interval. This is because:
1269 * xtime_interval = cycle_interval * mult
1270 * So if mult is being incremented by one:
1271 * xtime_interval = cycle_interval * (mult + 1)
1273 * xtime_interval = (cycle_interval * mult) + cycle_interval
1274 * Which can be shortened to:
1275 * xtime_interval += cycle_interval
1277 * So offset stores the non-accumulated cycles. Thus the current
1278 * time (in shifted nanoseconds) is:
1279 * now = (offset * adj) + xtime_nsec
1280 * Now, even though we're adjusting the clock frequency, we have
1281 * to keep time consistent. In other words, we can't jump back
1282 * in time, and we also want to avoid jumping forward in time.
1284 * So given the same offset value, we need the time to be the same
1285 * both before and after the freq adjustment.
1286 * now = (offset * adj_1) + xtime_nsec_1
1287 * now = (offset * adj_2) + xtime_nsec_2
1289 * (offset * adj_1) + xtime_nsec_1 =
1290 * (offset * adj_2) + xtime_nsec_2
1294 * (offset * adj_1) + xtime_nsec_1 =
1295 * (offset * (adj_1+1)) + xtime_nsec_2
1296 * (offset * adj_1) + xtime_nsec_1 =
1297 * (offset * adj_1) + offset + xtime_nsec_2
1298 * Canceling the sides:
1299 * xtime_nsec_1 = offset + xtime_nsec_2
1301 * xtime_nsec_2 = xtime_nsec_1 - offset
1302 * Which simplfies to:
1303 * xtime_nsec -= offset
1305 * XXX - TODO: Doc ntp_error calculation.
1308 tk
->xtime_interval
+= interval
;
1309 tk
->xtime_nsec
-= offset
;
1310 tk
->ntp_error
-= (interval
- offset
) << tk
->ntp_error_shift
;
1314 * It may be possible that when we entered this function, xtime_nsec
1315 * was very small. Further, if we're slightly speeding the clocksource
1316 * in the code above, its possible the required corrective factor to
1317 * xtime_nsec could cause it to underflow.
1319 * Now, since we already accumulated the second, cannot simply roll
1320 * the accumulated second back, since the NTP subsystem has been
1321 * notified via second_overflow. So instead we push xtime_nsec forward
1322 * by the amount we underflowed, and add that amount into the error.
1324 * We'll correct this error next time through this function, when
1325 * xtime_nsec is not as small.
1327 if (unlikely((s64
)tk
->xtime_nsec
< 0)) {
1328 s64 neg
= -(s64
)tk
->xtime_nsec
;
1330 tk
->ntp_error
+= neg
<< tk
->ntp_error_shift
;
1336 * accumulate_nsecs_to_secs - Accumulates nsecs into secs
1338 * Helper function that accumulates a the nsecs greater then a second
1339 * from the xtime_nsec field to the xtime_secs field.
1340 * It also calls into the NTP code to handle leapsecond processing.
1343 static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper
*tk
)
1345 u64 nsecps
= (u64
)NSEC_PER_SEC
<< tk
->shift
;
1346 unsigned int clock_set
= 0;
1348 while (tk
->xtime_nsec
>= nsecps
) {
1351 tk
->xtime_nsec
-= nsecps
;
1354 /* Figure out if its a leap sec and apply if needed */
1355 leap
= second_overflow(tk
->xtime_sec
);
1356 if (unlikely(leap
)) {
1357 struct timespec64 ts
;
1359 tk
->xtime_sec
+= leap
;
1363 tk_set_wall_to_mono(tk
,
1364 timespec64_sub(tk
->wall_to_monotonic
, ts
));
1366 __timekeeping_set_tai_offset(tk
, tk
->tai_offset
- leap
);
1368 clock_set
= TK_CLOCK_WAS_SET
;
1375 * logarithmic_accumulation - shifted accumulation of cycles
1377 * This functions accumulates a shifted interval of cycles into
1378 * into a shifted interval nanoseconds. Allows for O(log) accumulation
1381 * Returns the unconsumed cycles.
1383 static cycle_t
logarithmic_accumulation(struct timekeeper
*tk
, cycle_t offset
,
1385 unsigned int *clock_set
)
1387 cycle_t interval
= tk
->cycle_interval
<< shift
;
1390 /* If the offset is smaller then a shifted interval, do nothing */
1391 if (offset
< interval
)
1394 /* Accumulate one shifted interval */
1396 tk
->cycle_last
+= interval
;
1398 tk
->xtime_nsec
+= tk
->xtime_interval
<< shift
;
1399 *clock_set
|= accumulate_nsecs_to_secs(tk
);
1401 /* Accumulate raw time */
1402 raw_nsecs
= (u64
)tk
->raw_interval
<< shift
;
1403 raw_nsecs
+= tk
->raw_time
.tv_nsec
;
1404 if (raw_nsecs
>= NSEC_PER_SEC
) {
1405 u64 raw_secs
= raw_nsecs
;
1406 raw_nsecs
= do_div(raw_secs
, NSEC_PER_SEC
);
1407 tk
->raw_time
.tv_sec
+= raw_secs
;
1409 tk
->raw_time
.tv_nsec
= raw_nsecs
;
1411 /* Accumulate error between NTP and clock interval */
1412 tk
->ntp_error
+= ntp_tick_length() << shift
;
1413 tk
->ntp_error
-= (tk
->xtime_interval
+ tk
->xtime_remainder
) <<
1414 (tk
->ntp_error_shift
+ shift
);
1420 * update_wall_time - Uses the current clocksource to increment the wall time
1423 void update_wall_time(void)
1425 struct clocksource
*clock
;
1426 struct timekeeper
*real_tk
= &tk_core
.timekeeper
;
1427 struct timekeeper
*tk
= &shadow_timekeeper
;
1429 int shift
= 0, maxshift
;
1430 unsigned int clock_set
= 0;
1431 unsigned long flags
;
1433 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1435 /* Make sure we're fully resumed: */
1436 if (unlikely(timekeeping_suspended
))
1439 clock
= real_tk
->clock
;
1441 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
1442 offset
= real_tk
->cycle_interval
;
1444 offset
= (clock
->read(clock
) - clock
->cycle_last
) & clock
->mask
;
1447 /* Check if there's really nothing to do */
1448 if (offset
< real_tk
->cycle_interval
)
1452 * With NO_HZ we may have to accumulate many cycle_intervals
1453 * (think "ticks") worth of time at once. To do this efficiently,
1454 * we calculate the largest doubling multiple of cycle_intervals
1455 * that is smaller than the offset. We then accumulate that
1456 * chunk in one go, and then try to consume the next smaller
1459 shift
= ilog2(offset
) - ilog2(tk
->cycle_interval
);
1460 shift
= max(0, shift
);
1461 /* Bound shift to one less than what overflows tick_length */
1462 maxshift
= (64 - (ilog2(ntp_tick_length())+1)) - 1;
1463 shift
= min(shift
, maxshift
);
1464 while (offset
>= tk
->cycle_interval
) {
1465 offset
= logarithmic_accumulation(tk
, offset
, shift
,
1467 if (offset
< tk
->cycle_interval
<<shift
)
1471 /* correct the clock when NTP error is too big */
1472 timekeeping_adjust(tk
, offset
);
1475 * XXX This can be killed once everyone converts
1476 * to the new update_vsyscall.
1478 old_vsyscall_fixup(tk
);
1481 * Finally, make sure that after the rounding
1482 * xtime_nsec isn't larger than NSEC_PER_SEC
1484 clock_set
|= accumulate_nsecs_to_secs(tk
);
1486 write_seqcount_begin(&tk_core
.seq
);
1487 /* Update clock->cycle_last with the new value */
1488 clock
->cycle_last
= tk
->cycle_last
;
1490 * Update the real timekeeper.
1492 * We could avoid this memcpy by switching pointers, but that
1493 * requires changes to all other timekeeper usage sites as
1494 * well, i.e. move the timekeeper pointer getter into the
1495 * spinlocked/seqcount protected sections. And we trade this
1496 * memcpy under the tk_core.seq against one before we start
1499 memcpy(real_tk
, tk
, sizeof(*tk
));
1500 timekeeping_update(real_tk
, clock_set
);
1501 write_seqcount_end(&tk_core
.seq
);
1503 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1505 /* Have to call _delayed version, since in irq context*/
1506 clock_was_set_delayed();
1510 * getboottime - Return the real time of system boot.
1511 * @ts: pointer to the timespec to be set
1513 * Returns the wall-time of boot in a timespec.
1515 * This is based on the wall_to_monotonic offset and the total suspend
1516 * time. Calls to settimeofday will affect the value returned (which
1517 * basically means that however wrong your real time clock is at boot time,
1518 * you get the right time here).
1520 void getboottime(struct timespec
*ts
)
1522 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1523 struct timespec boottime
= {
1524 .tv_sec
= tk
->wall_to_monotonic
.tv_sec
+
1525 tk
->total_sleep_time
.tv_sec
,
1526 .tv_nsec
= tk
->wall_to_monotonic
.tv_nsec
+
1527 tk
->total_sleep_time
.tv_nsec
1530 set_normalized_timespec(ts
, -boottime
.tv_sec
, -boottime
.tv_nsec
);
1532 EXPORT_SYMBOL_GPL(getboottime
);
1535 * get_monotonic_boottime - Returns monotonic time since boot
1536 * @ts: pointer to the timespec to be set
1538 * Returns the monotonic time since boot in a timespec.
1540 * This is similar to CLOCK_MONTONIC/ktime_get_ts, but also
1541 * includes the time spent in suspend.
1543 void get_monotonic_boottime(struct timespec
*ts
)
1545 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1546 struct timespec64 tomono
, sleep
, ret
;
1550 WARN_ON(timekeeping_suspended
);
1553 seq
= read_seqcount_begin(&tk_core
.seq
);
1554 ret
.tv_sec
= tk
->xtime_sec
;
1555 nsec
= timekeeping_get_ns(tk
);
1556 tomono
= tk
->wall_to_monotonic
;
1557 sleep
= tk
->total_sleep_time
;
1559 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1561 ret
.tv_sec
+= tomono
.tv_sec
+ sleep
.tv_sec
;
1563 timespec64_add_ns(&ret
, nsec
+ tomono
.tv_nsec
+ sleep
.tv_nsec
);
1564 *ts
= timespec64_to_timespec(ret
);
1566 EXPORT_SYMBOL_GPL(get_monotonic_boottime
);
1569 * ktime_get_boottime - Returns monotonic time since boot in a ktime
1571 * Returns the monotonic time since boot in a ktime
1573 * This is similar to CLOCK_MONTONIC/ktime_get, but also
1574 * includes the time spent in suspend.
1576 ktime_t
ktime_get_boottime(void)
1580 get_monotonic_boottime(&ts
);
1581 return timespec_to_ktime(ts
);
1583 EXPORT_SYMBOL_GPL(ktime_get_boottime
);
1586 * monotonic_to_bootbased - Convert the monotonic time to boot based.
1587 * @ts: pointer to the timespec to be converted
1589 void monotonic_to_bootbased(struct timespec
*ts
)
1591 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1592 struct timespec64 ts64
;
1594 ts64
= timespec_to_timespec64(*ts
);
1595 ts64
= timespec64_add(ts64
, tk
->total_sleep_time
);
1596 *ts
= timespec64_to_timespec(ts64
);
1598 EXPORT_SYMBOL_GPL(monotonic_to_bootbased
);
1600 unsigned long get_seconds(void)
1602 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1604 return tk
->xtime_sec
;
1606 EXPORT_SYMBOL(get_seconds
);
1608 struct timespec
__current_kernel_time(void)
1610 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1612 return timespec64_to_timespec(tk_xtime(tk
));
1615 struct timespec
current_kernel_time(void)
1617 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1618 struct timespec64 now
;
1622 seq
= read_seqcount_begin(&tk_core
.seq
);
1625 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1627 return timespec64_to_timespec(now
);
1629 EXPORT_SYMBOL(current_kernel_time
);
1631 struct timespec
get_monotonic_coarse(void)
1633 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1634 struct timespec64 now
, mono
;
1638 seq
= read_seqcount_begin(&tk_core
.seq
);
1641 mono
= tk
->wall_to_monotonic
;
1642 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1644 set_normalized_timespec64(&now
, now
.tv_sec
+ mono
.tv_sec
,
1645 now
.tv_nsec
+ mono
.tv_nsec
);
1647 return timespec64_to_timespec(now
);
1651 * Must hold jiffies_lock
1653 void do_timer(unsigned long ticks
)
1655 jiffies_64
+= ticks
;
1656 calc_global_load(ticks
);
1660 * ktime_get_update_offsets_tick - hrtimer helper
1661 * @offs_real: pointer to storage for monotonic -> realtime offset
1662 * @offs_boot: pointer to storage for monotonic -> boottime offset
1663 * @offs_tai: pointer to storage for monotonic -> clock tai offset
1665 * Returns monotonic time at last tick and various offsets
1667 ktime_t
ktime_get_update_offsets_tick(ktime_t
*offs_real
, ktime_t
*offs_boot
,
1670 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1671 struct timespec64 ts
;
1676 seq
= read_seqcount_begin(&tk_core
.seq
);
1679 *offs_real
= tk
->offs_real
;
1680 *offs_boot
= tk
->offs_boot
;
1681 *offs_tai
= tk
->offs_tai
;
1682 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1684 now
= ktime_set(ts
.tv_sec
, ts
.tv_nsec
);
1685 now
= ktime_sub(now
, *offs_real
);
1689 #ifdef CONFIG_HIGH_RES_TIMERS
1691 * ktime_get_update_offsets_now - hrtimer helper
1692 * @offs_real: pointer to storage for monotonic -> realtime offset
1693 * @offs_boot: pointer to storage for monotonic -> boottime offset
1694 * @offs_tai: pointer to storage for monotonic -> clock tai offset
1696 * Returns current monotonic time and updates the offsets
1697 * Called from hrtimer_interrupt() or retrigger_next_event()
1699 ktime_t
ktime_get_update_offsets_now(ktime_t
*offs_real
, ktime_t
*offs_boot
,
1702 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1708 seq
= read_seqcount_begin(&tk_core
.seq
);
1710 secs
= tk
->xtime_sec
;
1711 nsecs
= timekeeping_get_ns(tk
);
1713 *offs_real
= tk
->offs_real
;
1714 *offs_boot
= tk
->offs_boot
;
1715 *offs_tai
= tk
->offs_tai
;
1716 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1718 now
= ktime_add_ns(ktime_set(secs
, 0), nsecs
);
1719 now
= ktime_sub(now
, *offs_real
);
1725 * ktime_get_monotonic_offset() - get wall_to_monotonic in ktime_t format
1727 ktime_t
ktime_get_monotonic_offset(void)
1729 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1731 struct timespec64 wtom
;
1734 seq
= read_seqcount_begin(&tk_core
.seq
);
1735 wtom
= tk
->wall_to_monotonic
;
1736 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1738 return timespec64_to_ktime(wtom
);
1740 EXPORT_SYMBOL_GPL(ktime_get_monotonic_offset
);
1743 * do_adjtimex() - Accessor function to NTP __do_adjtimex function
1745 int do_adjtimex(struct timex
*txc
)
1747 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1748 unsigned long flags
;
1749 struct timespec64 ts
;
1753 /* Validate the data before disabling interrupts */
1754 ret
= ntp_validate_timex(txc
);
1758 if (txc
->modes
& ADJ_SETOFFSET
) {
1759 struct timespec delta
;
1760 delta
.tv_sec
= txc
->time
.tv_sec
;
1761 delta
.tv_nsec
= txc
->time
.tv_usec
;
1762 if (!(txc
->modes
& ADJ_NANO
))
1763 delta
.tv_nsec
*= 1000;
1764 ret
= timekeeping_inject_offset(&delta
);
1769 getnstimeofday64(&ts
);
1771 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1772 write_seqcount_begin(&tk_core
.seq
);
1774 orig_tai
= tai
= tk
->tai_offset
;
1775 ret
= __do_adjtimex(txc
, &ts
, &tai
);
1777 if (tai
!= orig_tai
) {
1778 __timekeeping_set_tai_offset(tk
, tai
);
1779 timekeeping_update(tk
, TK_MIRROR
| TK_CLOCK_WAS_SET
);
1781 write_seqcount_end(&tk_core
.seq
);
1782 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1784 if (tai
!= orig_tai
)
1787 ntp_notify_cmos_timer();
1792 #ifdef CONFIG_NTP_PPS
1794 * hardpps() - Accessor function to NTP __hardpps function
1796 void hardpps(const struct timespec
*phase_ts
, const struct timespec
*raw_ts
)
1798 unsigned long flags
;
1800 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1801 write_seqcount_begin(&tk_core
.seq
);
1803 __hardpps(phase_ts
, raw_ts
);
1805 write_seqcount_end(&tk_core
.seq
);
1806 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1808 EXPORT_SYMBOL(hardpps
);
1812 * xtime_update() - advances the timekeeping infrastructure
1813 * @ticks: number of ticks, that have elapsed since the last call.
1815 * Must be called with interrupts disabled.
1817 void xtime_update(unsigned long ticks
)
1819 write_seqlock(&jiffies_lock
);
1821 write_sequnlock(&jiffies_lock
);