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
;
48 * struct tk_fast - NMI safe timekeeper
49 * @seq: Sequence counter for protecting updates. The lowest bit
50 * is the index for the tk_read_base array
51 * @base: tk_read_base array. Access is indexed by the lowest bit of
54 * See @update_fast_timekeeper() below.
58 struct tk_read_base base
[2];
61 static struct tk_fast tk_fast_mono ____cacheline_aligned
;
63 /* flag for if timekeeping is suspended */
64 int __read_mostly timekeeping_suspended
;
66 /* Flag for if there is a persistent clock on this platform */
67 bool __read_mostly persistent_clock_exist
= false;
69 static inline void tk_normalize_xtime(struct timekeeper
*tk
)
71 while (tk
->tkr
.xtime_nsec
>= ((u64
)NSEC_PER_SEC
<< tk
->tkr
.shift
)) {
72 tk
->tkr
.xtime_nsec
-= (u64
)NSEC_PER_SEC
<< tk
->tkr
.shift
;
77 static inline struct timespec64
tk_xtime(struct timekeeper
*tk
)
81 ts
.tv_sec
= tk
->xtime_sec
;
82 ts
.tv_nsec
= (long)(tk
->tkr
.xtime_nsec
>> tk
->tkr
.shift
);
86 static void tk_set_xtime(struct timekeeper
*tk
, const struct timespec64
*ts
)
88 tk
->xtime_sec
= ts
->tv_sec
;
89 tk
->tkr
.xtime_nsec
= (u64
)ts
->tv_nsec
<< tk
->tkr
.shift
;
92 static void tk_xtime_add(struct timekeeper
*tk
, const struct timespec64
*ts
)
94 tk
->xtime_sec
+= ts
->tv_sec
;
95 tk
->tkr
.xtime_nsec
+= (u64
)ts
->tv_nsec
<< tk
->tkr
.shift
;
96 tk_normalize_xtime(tk
);
99 static void tk_set_wall_to_mono(struct timekeeper
*tk
, struct timespec64 wtm
)
101 struct timespec64 tmp
;
104 * Verify consistency of: offset_real = -wall_to_monotonic
105 * before modifying anything
107 set_normalized_timespec64(&tmp
, -tk
->wall_to_monotonic
.tv_sec
,
108 -tk
->wall_to_monotonic
.tv_nsec
);
109 WARN_ON_ONCE(tk
->offs_real
.tv64
!= timespec64_to_ktime(tmp
).tv64
);
110 tk
->wall_to_monotonic
= wtm
;
111 set_normalized_timespec64(&tmp
, -wtm
.tv_sec
, -wtm
.tv_nsec
);
112 tk
->offs_real
= timespec64_to_ktime(tmp
);
113 tk
->offs_tai
= ktime_add(tk
->offs_real
, ktime_set(tk
->tai_offset
, 0));
116 static inline void tk_update_sleep_time(struct timekeeper
*tk
, ktime_t delta
)
118 tk
->offs_boot
= ktime_add(tk
->offs_boot
, delta
);
122 * tk_setup_internals - Set up internals to use clocksource clock.
124 * @tk: The target timekeeper to setup.
125 * @clock: Pointer to clocksource.
127 * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
128 * pair and interval request.
130 * Unless you're the timekeeping code, you should not be using this!
132 static void tk_setup_internals(struct timekeeper
*tk
, struct clocksource
*clock
)
135 u64 tmp
, ntpinterval
;
136 struct clocksource
*old_clock
;
138 old_clock
= tk
->tkr
.clock
;
139 tk
->tkr
.clock
= clock
;
140 tk
->tkr
.read
= clock
->read
;
141 tk
->tkr
.mask
= clock
->mask
;
142 tk
->tkr
.cycle_last
= tk
->tkr
.read(clock
);
144 /* Do the ns -> cycle conversion first, using original mult */
145 tmp
= NTP_INTERVAL_LENGTH
;
146 tmp
<<= clock
->shift
;
148 tmp
+= clock
->mult
/2;
149 do_div(tmp
, clock
->mult
);
153 interval
= (cycle_t
) tmp
;
154 tk
->cycle_interval
= interval
;
156 /* Go back from cycles -> shifted ns */
157 tk
->xtime_interval
= (u64
) interval
* clock
->mult
;
158 tk
->xtime_remainder
= ntpinterval
- tk
->xtime_interval
;
160 ((u64
) interval
* clock
->mult
) >> clock
->shift
;
162 /* if changing clocks, convert xtime_nsec shift units */
164 int shift_change
= clock
->shift
- old_clock
->shift
;
165 if (shift_change
< 0)
166 tk
->tkr
.xtime_nsec
>>= -shift_change
;
168 tk
->tkr
.xtime_nsec
<<= shift_change
;
170 tk
->tkr
.shift
= clock
->shift
;
173 tk
->ntp_error_shift
= NTP_SCALE_SHIFT
- clock
->shift
;
174 tk
->ntp_tick
= ntpinterval
<< tk
->ntp_error_shift
;
177 * The timekeeper keeps its own mult values for the currently
178 * active clocksource. These value will be adjusted via NTP
179 * to counteract clock drifting.
181 tk
->tkr
.mult
= clock
->mult
;
182 tk
->ntp_err_mult
= 0;
185 /* Timekeeper helper functions. */
187 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
188 static u32
default_arch_gettimeoffset(void) { return 0; }
189 u32 (*arch_gettimeoffset
)(void) = default_arch_gettimeoffset
;
191 static inline u32
arch_gettimeoffset(void) { return 0; }
194 static inline s64
timekeeping_get_ns(struct tk_read_base
*tkr
)
196 cycle_t cycle_now
, delta
;
199 /* read clocksource: */
200 cycle_now
= tkr
->read(tkr
->clock
);
202 /* calculate the delta since the last update_wall_time: */
203 delta
= clocksource_delta(cycle_now
, tkr
->cycle_last
, tkr
->mask
);
205 nsec
= delta
* tkr
->mult
+ tkr
->xtime_nsec
;
208 /* If arch requires, add in get_arch_timeoffset() */
209 return nsec
+ arch_gettimeoffset();
212 static inline s64
timekeeping_get_ns_raw(struct timekeeper
*tk
)
214 struct clocksource
*clock
= tk
->tkr
.clock
;
215 cycle_t cycle_now
, delta
;
218 /* read clocksource: */
219 cycle_now
= tk
->tkr
.read(clock
);
221 /* calculate the delta since the last update_wall_time: */
222 delta
= clocksource_delta(cycle_now
, tk
->tkr
.cycle_last
, tk
->tkr
.mask
);
224 /* convert delta to nanoseconds. */
225 nsec
= clocksource_cyc2ns(delta
, clock
->mult
, clock
->shift
);
227 /* If arch requires, add in get_arch_timeoffset() */
228 return nsec
+ arch_gettimeoffset();
232 * update_fast_timekeeper - Update the fast and NMI safe monotonic timekeeper.
233 * @tk: The timekeeper from which we take the update
234 * @tkf: The fast timekeeper to update
235 * @tbase: The time base for the fast timekeeper (mono/raw)
237 * We want to use this from any context including NMI and tracing /
238 * instrumenting the timekeeping code itself.
240 * So we handle this differently than the other timekeeping accessor
241 * functions which retry when the sequence count has changed. The
244 * smp_wmb(); <- Ensure that the last base[1] update is visible
246 * smp_wmb(); <- Ensure that the seqcount update is visible
247 * update(tkf->base[0], tk);
248 * smp_wmb(); <- Ensure that the base[0] update is visible
250 * smp_wmb(); <- Ensure that the seqcount update is visible
251 * update(tkf->base[1], tk);
253 * The reader side does:
259 * now = now(tkf->base[idx]);
261 * } while (seq != tkf->seq)
263 * As long as we update base[0] readers are forced off to
264 * base[1]. Once base[0] is updated readers are redirected to base[0]
265 * and the base[1] update takes place.
267 * So if a NMI hits the update of base[0] then it will use base[1]
268 * which is still consistent. In the worst case this can result is a
269 * slightly wrong timestamp (a few nanoseconds). See
270 * @ktime_get_mono_fast_ns.
272 static void update_fast_timekeeper(struct timekeeper
*tk
)
274 struct tk_read_base
*base
= tk_fast_mono
.base
;
276 /* Force readers off to base[1] */
277 raw_write_seqcount_latch(&tk_fast_mono
.seq
);
280 memcpy(base
, &tk
->tkr
, sizeof(*base
));
282 /* Force readers back to base[0] */
283 raw_write_seqcount_latch(&tk_fast_mono
.seq
);
286 memcpy(base
+ 1, base
, sizeof(*base
));
290 * ktime_get_mono_fast_ns - Fast NMI safe access to clock monotonic
292 * This timestamp is not guaranteed to be monotonic across an update.
293 * The timestamp is calculated by:
295 * now = base_mono + clock_delta * slope
297 * So if the update lowers the slope, readers who are forced to the
298 * not yet updated second array are still using the old steeper slope.
307 * |12345678---> reader order
313 * So reader 6 will observe time going backwards versus reader 5.
315 * While other CPUs are likely to be able observe that, the only way
316 * for a CPU local observation is when an NMI hits in the middle of
317 * the update. Timestamps taken from that NMI context might be ahead
318 * of the following timestamps. Callers need to be aware of that and
321 u64 notrace
ktime_get_mono_fast_ns(void)
323 struct tk_read_base
*tkr
;
328 seq
= raw_read_seqcount(&tk_fast_mono
.seq
);
329 tkr
= tk_fast_mono
.base
+ (seq
& 0x01);
330 now
= ktime_to_ns(tkr
->base_mono
) + timekeeping_get_ns(tkr
);
332 } while (read_seqcount_retry(&tk_fast_mono
.seq
, seq
));
335 EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns
);
337 #ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD
339 static inline void update_vsyscall(struct timekeeper
*tk
)
343 xt
= timespec64_to_timespec(tk_xtime(tk
));
344 update_vsyscall_old(&xt
, &tk
->wall_to_monotonic
, tk
->tkr
.clock
, tk
->tkr
.mult
,
348 static inline void old_vsyscall_fixup(struct timekeeper
*tk
)
353 * Store only full nanoseconds into xtime_nsec after rounding
354 * it up and add the remainder to the error difference.
355 * XXX - This is necessary to avoid small 1ns inconsistnecies caused
356 * by truncating the remainder in vsyscalls. However, it causes
357 * additional work to be done in timekeeping_adjust(). Once
358 * the vsyscall implementations are converted to use xtime_nsec
359 * (shifted nanoseconds), and CONFIG_GENERIC_TIME_VSYSCALL_OLD
360 * users are removed, this can be killed.
362 remainder
= tk
->tkr
.xtime_nsec
& ((1ULL << tk
->tkr
.shift
) - 1);
363 tk
->tkr
.xtime_nsec
-= remainder
;
364 tk
->tkr
.xtime_nsec
+= 1ULL << tk
->tkr
.shift
;
365 tk
->ntp_error
+= remainder
<< tk
->ntp_error_shift
;
366 tk
->ntp_error
-= (1ULL << tk
->tkr
.shift
) << tk
->ntp_error_shift
;
369 #define old_vsyscall_fixup(tk)
372 static RAW_NOTIFIER_HEAD(pvclock_gtod_chain
);
374 static void update_pvclock_gtod(struct timekeeper
*tk
, bool was_set
)
376 raw_notifier_call_chain(&pvclock_gtod_chain
, was_set
, tk
);
380 * pvclock_gtod_register_notifier - register a pvclock timedata update listener
382 int pvclock_gtod_register_notifier(struct notifier_block
*nb
)
384 struct timekeeper
*tk
= &tk_core
.timekeeper
;
388 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
389 ret
= raw_notifier_chain_register(&pvclock_gtod_chain
, nb
);
390 update_pvclock_gtod(tk
, true);
391 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
395 EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier
);
398 * pvclock_gtod_unregister_notifier - unregister a pvclock
399 * timedata update listener
401 int pvclock_gtod_unregister_notifier(struct notifier_block
*nb
)
406 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
407 ret
= raw_notifier_chain_unregister(&pvclock_gtod_chain
, nb
);
408 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
412 EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier
);
415 * Update the ktime_t based scalar nsec members of the timekeeper
417 static inline void tk_update_ktime_data(struct timekeeper
*tk
)
422 * The xtime based monotonic readout is:
423 * nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();
424 * The ktime based monotonic readout is:
425 * nsec = base_mono + now();
426 * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec
428 nsec
= (s64
)(tk
->xtime_sec
+ tk
->wall_to_monotonic
.tv_sec
);
429 nsec
*= NSEC_PER_SEC
;
430 nsec
+= tk
->wall_to_monotonic
.tv_nsec
;
431 tk
->tkr
.base_mono
= ns_to_ktime(nsec
);
433 /* Update the monotonic raw base */
434 tk
->base_raw
= timespec64_to_ktime(tk
->raw_time
);
437 /* must hold timekeeper_lock */
438 static void timekeeping_update(struct timekeeper
*tk
, unsigned int action
)
440 if (action
& TK_CLEAR_NTP
) {
445 update_pvclock_gtod(tk
, action
& TK_CLOCK_WAS_SET
);
447 tk_update_ktime_data(tk
);
449 if (action
& TK_MIRROR
)
450 memcpy(&shadow_timekeeper
, &tk_core
.timekeeper
,
451 sizeof(tk_core
.timekeeper
));
453 update_fast_timekeeper(tk
);
457 * timekeeping_forward_now - update clock to the current time
459 * Forward the current clock to update its state since the last call to
460 * update_wall_time(). This is useful before significant clock changes,
461 * as it avoids having to deal with this time offset explicitly.
463 static void timekeeping_forward_now(struct timekeeper
*tk
)
465 struct clocksource
*clock
= tk
->tkr
.clock
;
466 cycle_t cycle_now
, delta
;
469 cycle_now
= tk
->tkr
.read(clock
);
470 delta
= clocksource_delta(cycle_now
, tk
->tkr
.cycle_last
, tk
->tkr
.mask
);
471 tk
->tkr
.cycle_last
= cycle_now
;
473 tk
->tkr
.xtime_nsec
+= delta
* tk
->tkr
.mult
;
475 /* If arch requires, add in get_arch_timeoffset() */
476 tk
->tkr
.xtime_nsec
+= (u64
)arch_gettimeoffset() << tk
->tkr
.shift
;
478 tk_normalize_xtime(tk
);
480 nsec
= clocksource_cyc2ns(delta
, clock
->mult
, clock
->shift
);
481 timespec64_add_ns(&tk
->raw_time
, nsec
);
485 * __getnstimeofday64 - Returns the time of day in a timespec64.
486 * @ts: pointer to the timespec to be set
488 * Updates the time of day in the timespec.
489 * Returns 0 on success, or -ve when suspended (timespec will be undefined).
491 int __getnstimeofday64(struct timespec64
*ts
)
493 struct timekeeper
*tk
= &tk_core
.timekeeper
;
498 seq
= read_seqcount_begin(&tk_core
.seq
);
500 ts
->tv_sec
= tk
->xtime_sec
;
501 nsecs
= timekeeping_get_ns(&tk
->tkr
);
503 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
506 timespec64_add_ns(ts
, nsecs
);
509 * Do not bail out early, in case there were callers still using
510 * the value, even in the face of the WARN_ON.
512 if (unlikely(timekeeping_suspended
))
516 EXPORT_SYMBOL(__getnstimeofday64
);
519 * getnstimeofday64 - Returns the time of day in a timespec64.
520 * @ts: pointer to the timespec to be set
522 * Returns the time of day in a timespec (WARN if suspended).
524 void getnstimeofday64(struct timespec64
*ts
)
526 WARN_ON(__getnstimeofday64(ts
));
528 EXPORT_SYMBOL(getnstimeofday64
);
530 ktime_t
ktime_get(void)
532 struct timekeeper
*tk
= &tk_core
.timekeeper
;
537 WARN_ON(timekeeping_suspended
);
540 seq
= read_seqcount_begin(&tk_core
.seq
);
541 base
= tk
->tkr
.base_mono
;
542 nsecs
= timekeeping_get_ns(&tk
->tkr
);
544 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
546 return ktime_add_ns(base
, nsecs
);
548 EXPORT_SYMBOL_GPL(ktime_get
);
550 static ktime_t
*offsets
[TK_OFFS_MAX
] = {
551 [TK_OFFS_REAL
] = &tk_core
.timekeeper
.offs_real
,
552 [TK_OFFS_BOOT
] = &tk_core
.timekeeper
.offs_boot
,
553 [TK_OFFS_TAI
] = &tk_core
.timekeeper
.offs_tai
,
556 ktime_t
ktime_get_with_offset(enum tk_offsets offs
)
558 struct timekeeper
*tk
= &tk_core
.timekeeper
;
560 ktime_t base
, *offset
= offsets
[offs
];
563 WARN_ON(timekeeping_suspended
);
566 seq
= read_seqcount_begin(&tk_core
.seq
);
567 base
= ktime_add(tk
->tkr
.base_mono
, *offset
);
568 nsecs
= timekeeping_get_ns(&tk
->tkr
);
570 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
572 return ktime_add_ns(base
, nsecs
);
575 EXPORT_SYMBOL_GPL(ktime_get_with_offset
);
578 * ktime_mono_to_any() - convert mononotic time to any other time
579 * @tmono: time to convert.
580 * @offs: which offset to use
582 ktime_t
ktime_mono_to_any(ktime_t tmono
, enum tk_offsets offs
)
584 ktime_t
*offset
= offsets
[offs
];
589 seq
= read_seqcount_begin(&tk_core
.seq
);
590 tconv
= ktime_add(tmono
, *offset
);
591 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
595 EXPORT_SYMBOL_GPL(ktime_mono_to_any
);
598 * ktime_get_raw - Returns the raw monotonic time in ktime_t format
600 ktime_t
ktime_get_raw(void)
602 struct timekeeper
*tk
= &tk_core
.timekeeper
;
608 seq
= read_seqcount_begin(&tk_core
.seq
);
610 nsecs
= timekeeping_get_ns_raw(tk
);
612 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
614 return ktime_add_ns(base
, nsecs
);
616 EXPORT_SYMBOL_GPL(ktime_get_raw
);
619 * ktime_get_ts64 - get the monotonic clock in timespec64 format
620 * @ts: pointer to timespec variable
622 * The function calculates the monotonic clock from the realtime
623 * clock and the wall_to_monotonic offset and stores the result
624 * in normalized timespec format in the variable pointed to by @ts.
626 void ktime_get_ts64(struct timespec64
*ts
)
628 struct timekeeper
*tk
= &tk_core
.timekeeper
;
629 struct timespec64 tomono
;
633 WARN_ON(timekeeping_suspended
);
636 seq
= read_seqcount_begin(&tk_core
.seq
);
637 ts
->tv_sec
= tk
->xtime_sec
;
638 nsec
= timekeeping_get_ns(&tk
->tkr
);
639 tomono
= tk
->wall_to_monotonic
;
641 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
643 ts
->tv_sec
+= tomono
.tv_sec
;
645 timespec64_add_ns(ts
, nsec
+ tomono
.tv_nsec
);
647 EXPORT_SYMBOL_GPL(ktime_get_ts64
);
649 #ifdef CONFIG_NTP_PPS
652 * getnstime_raw_and_real - get day and raw monotonic time in timespec format
653 * @ts_raw: pointer to the timespec to be set to raw monotonic time
654 * @ts_real: pointer to the timespec to be set to the time of day
656 * This function reads both the time of day and raw monotonic time at the
657 * same time atomically and stores the resulting timestamps in timespec
660 void getnstime_raw_and_real(struct timespec
*ts_raw
, struct timespec
*ts_real
)
662 struct timekeeper
*tk
= &tk_core
.timekeeper
;
664 s64 nsecs_raw
, nsecs_real
;
666 WARN_ON_ONCE(timekeeping_suspended
);
669 seq
= read_seqcount_begin(&tk_core
.seq
);
671 *ts_raw
= timespec64_to_timespec(tk
->raw_time
);
672 ts_real
->tv_sec
= tk
->xtime_sec
;
673 ts_real
->tv_nsec
= 0;
675 nsecs_raw
= timekeeping_get_ns_raw(tk
);
676 nsecs_real
= timekeeping_get_ns(&tk
->tkr
);
678 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
680 timespec_add_ns(ts_raw
, nsecs_raw
);
681 timespec_add_ns(ts_real
, nsecs_real
);
683 EXPORT_SYMBOL(getnstime_raw_and_real
);
685 #endif /* CONFIG_NTP_PPS */
688 * do_gettimeofday - Returns the time of day in a timeval
689 * @tv: pointer to the timeval to be set
691 * NOTE: Users should be converted to using getnstimeofday()
693 void do_gettimeofday(struct timeval
*tv
)
695 struct timespec64 now
;
697 getnstimeofday64(&now
);
698 tv
->tv_sec
= now
.tv_sec
;
699 tv
->tv_usec
= now
.tv_nsec
/1000;
701 EXPORT_SYMBOL(do_gettimeofday
);
704 * do_settimeofday - Sets the time of day
705 * @tv: pointer to the timespec variable containing the new time
707 * Sets the time of day to the new time and update NTP and notify hrtimers
709 int do_settimeofday(const struct timespec
*tv
)
711 struct timekeeper
*tk
= &tk_core
.timekeeper
;
712 struct timespec64 ts_delta
, xt
, tmp
;
715 if (!timespec_valid_strict(tv
))
718 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
719 write_seqcount_begin(&tk_core
.seq
);
721 timekeeping_forward_now(tk
);
724 ts_delta
.tv_sec
= tv
->tv_sec
- xt
.tv_sec
;
725 ts_delta
.tv_nsec
= tv
->tv_nsec
- xt
.tv_nsec
;
727 tk_set_wall_to_mono(tk
, timespec64_sub(tk
->wall_to_monotonic
, ts_delta
));
729 tmp
= timespec_to_timespec64(*tv
);
730 tk_set_xtime(tk
, &tmp
);
732 timekeeping_update(tk
, TK_CLEAR_NTP
| TK_MIRROR
| TK_CLOCK_WAS_SET
);
734 write_seqcount_end(&tk_core
.seq
);
735 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
737 /* signal hrtimers about time change */
742 EXPORT_SYMBOL(do_settimeofday
);
745 * timekeeping_inject_offset - Adds or subtracts from the current time.
746 * @tv: pointer to the timespec variable containing the offset
748 * Adds or subtracts an offset value from the current time.
750 int timekeeping_inject_offset(struct timespec
*ts
)
752 struct timekeeper
*tk
= &tk_core
.timekeeper
;
754 struct timespec64 ts64
, tmp
;
757 if ((unsigned long)ts
->tv_nsec
>= NSEC_PER_SEC
)
760 ts64
= timespec_to_timespec64(*ts
);
762 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
763 write_seqcount_begin(&tk_core
.seq
);
765 timekeeping_forward_now(tk
);
767 /* Make sure the proposed value is valid */
768 tmp
= timespec64_add(tk_xtime(tk
), ts64
);
769 if (!timespec64_valid_strict(&tmp
)) {
774 tk_xtime_add(tk
, &ts64
);
775 tk_set_wall_to_mono(tk
, timespec64_sub(tk
->wall_to_monotonic
, ts64
));
777 error
: /* even if we error out, we forwarded the time, so call update */
778 timekeeping_update(tk
, TK_CLEAR_NTP
| TK_MIRROR
| TK_CLOCK_WAS_SET
);
780 write_seqcount_end(&tk_core
.seq
);
781 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
783 /* signal hrtimers about time change */
788 EXPORT_SYMBOL(timekeeping_inject_offset
);
792 * timekeeping_get_tai_offset - Returns current TAI offset from UTC
795 s32
timekeeping_get_tai_offset(void)
797 struct timekeeper
*tk
= &tk_core
.timekeeper
;
802 seq
= read_seqcount_begin(&tk_core
.seq
);
803 ret
= tk
->tai_offset
;
804 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
810 * __timekeeping_set_tai_offset - Lock free worker function
813 static void __timekeeping_set_tai_offset(struct timekeeper
*tk
, s32 tai_offset
)
815 tk
->tai_offset
= tai_offset
;
816 tk
->offs_tai
= ktime_add(tk
->offs_real
, ktime_set(tai_offset
, 0));
820 * timekeeping_set_tai_offset - Sets the current TAI offset from UTC
823 void timekeeping_set_tai_offset(s32 tai_offset
)
825 struct timekeeper
*tk
= &tk_core
.timekeeper
;
828 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
829 write_seqcount_begin(&tk_core
.seq
);
830 __timekeeping_set_tai_offset(tk
, tai_offset
);
831 timekeeping_update(tk
, TK_MIRROR
| TK_CLOCK_WAS_SET
);
832 write_seqcount_end(&tk_core
.seq
);
833 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
838 * change_clocksource - Swaps clocksources if a new one is available
840 * Accumulates current time interval and initializes new clocksource
842 static int change_clocksource(void *data
)
844 struct timekeeper
*tk
= &tk_core
.timekeeper
;
845 struct clocksource
*new, *old
;
848 new = (struct clocksource
*) data
;
850 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
851 write_seqcount_begin(&tk_core
.seq
);
853 timekeeping_forward_now(tk
);
855 * If the cs is in module, get a module reference. Succeeds
856 * for built-in code (owner == NULL) as well.
858 if (try_module_get(new->owner
)) {
859 if (!new->enable
|| new->enable(new) == 0) {
861 tk_setup_internals(tk
, new);
864 module_put(old
->owner
);
866 module_put(new->owner
);
869 timekeeping_update(tk
, TK_CLEAR_NTP
| TK_MIRROR
| TK_CLOCK_WAS_SET
);
871 write_seqcount_end(&tk_core
.seq
);
872 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
878 * timekeeping_notify - Install a new clock source
879 * @clock: pointer to the clock source
881 * This function is called from clocksource.c after a new, better clock
882 * source has been registered. The caller holds the clocksource_mutex.
884 int timekeeping_notify(struct clocksource
*clock
)
886 struct timekeeper
*tk
= &tk_core
.timekeeper
;
888 if (tk
->tkr
.clock
== clock
)
890 stop_machine(change_clocksource
, clock
, NULL
);
892 return tk
->tkr
.clock
== clock
? 0 : -1;
896 * getrawmonotonic - Returns the raw monotonic time in a timespec
897 * @ts: pointer to the timespec to be set
899 * Returns the raw monotonic time (completely un-modified by ntp)
901 void getrawmonotonic(struct timespec
*ts
)
903 struct timekeeper
*tk
= &tk_core
.timekeeper
;
904 struct timespec64 ts64
;
909 seq
= read_seqcount_begin(&tk_core
.seq
);
910 nsecs
= timekeeping_get_ns_raw(tk
);
913 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
915 timespec64_add_ns(&ts64
, nsecs
);
916 *ts
= timespec64_to_timespec(ts64
);
918 EXPORT_SYMBOL(getrawmonotonic
);
921 * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
923 int timekeeping_valid_for_hres(void)
925 struct timekeeper
*tk
= &tk_core
.timekeeper
;
930 seq
= read_seqcount_begin(&tk_core
.seq
);
932 ret
= tk
->tkr
.clock
->flags
& CLOCK_SOURCE_VALID_FOR_HRES
;
934 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
940 * timekeeping_max_deferment - Returns max time the clocksource can be deferred
942 u64
timekeeping_max_deferment(void)
944 struct timekeeper
*tk
= &tk_core
.timekeeper
;
949 seq
= read_seqcount_begin(&tk_core
.seq
);
951 ret
= tk
->tkr
.clock
->max_idle_ns
;
953 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
959 * read_persistent_clock - Return time from the persistent clock.
961 * Weak dummy function for arches that do not yet support it.
962 * Reads the time from the battery backed persistent clock.
963 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
965 * XXX - Do be sure to remove it once all arches implement it.
967 void __weak
read_persistent_clock(struct timespec
*ts
)
974 * read_boot_clock - Return time of the system start.
976 * Weak dummy function for arches that do not yet support it.
977 * Function to read the exact time the system has been started.
978 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
980 * XXX - Do be sure to remove it once all arches implement it.
982 void __weak
read_boot_clock(struct timespec
*ts
)
989 * timekeeping_init - Initializes the clocksource and common timekeeping values
991 void __init
timekeeping_init(void)
993 struct timekeeper
*tk
= &tk_core
.timekeeper
;
994 struct clocksource
*clock
;
996 struct timespec64 now
, boot
, tmp
;
999 read_persistent_clock(&ts
);
1000 now
= timespec_to_timespec64(ts
);
1001 if (!timespec64_valid_strict(&now
)) {
1002 pr_warn("WARNING: Persistent clock returned invalid value!\n"
1003 " Check your CMOS/BIOS settings.\n");
1006 } else if (now
.tv_sec
|| now
.tv_nsec
)
1007 persistent_clock_exist
= true;
1009 read_boot_clock(&ts
);
1010 boot
= timespec_to_timespec64(ts
);
1011 if (!timespec64_valid_strict(&boot
)) {
1012 pr_warn("WARNING: Boot clock returned invalid value!\n"
1013 " Check your CMOS/BIOS settings.\n");
1018 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1019 write_seqcount_begin(&tk_core
.seq
);
1022 clock
= clocksource_default_clock();
1024 clock
->enable(clock
);
1025 tk_setup_internals(tk
, clock
);
1027 tk_set_xtime(tk
, &now
);
1028 tk
->raw_time
.tv_sec
= 0;
1029 tk
->raw_time
.tv_nsec
= 0;
1030 tk
->base_raw
.tv64
= 0;
1031 if (boot
.tv_sec
== 0 && boot
.tv_nsec
== 0)
1032 boot
= tk_xtime(tk
);
1034 set_normalized_timespec64(&tmp
, -boot
.tv_sec
, -boot
.tv_nsec
);
1035 tk_set_wall_to_mono(tk
, tmp
);
1037 timekeeping_update(tk
, TK_MIRROR
);
1039 write_seqcount_end(&tk_core
.seq
);
1040 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1043 /* time in seconds when suspend began */
1044 static struct timespec64 timekeeping_suspend_time
;
1047 * __timekeeping_inject_sleeptime - Internal function to add sleep interval
1048 * @delta: pointer to a timespec delta value
1050 * Takes a timespec offset measuring a suspend interval and properly
1051 * adds the sleep offset to the timekeeping variables.
1053 static void __timekeeping_inject_sleeptime(struct timekeeper
*tk
,
1054 struct timespec64
*delta
)
1056 if (!timespec64_valid_strict(delta
)) {
1057 printk_deferred(KERN_WARNING
1058 "__timekeeping_inject_sleeptime: Invalid "
1059 "sleep delta value!\n");
1062 tk_xtime_add(tk
, delta
);
1063 tk_set_wall_to_mono(tk
, timespec64_sub(tk
->wall_to_monotonic
, *delta
));
1064 tk_update_sleep_time(tk
, timespec64_to_ktime(*delta
));
1065 tk_debug_account_sleep_time(delta
);
1069 * timekeeping_inject_sleeptime - Adds suspend interval to timeekeeping values
1070 * @delta: pointer to a timespec delta value
1072 * This hook is for architectures that cannot support read_persistent_clock
1073 * because their RTC/persistent clock is only accessible when irqs are enabled.
1075 * This function should only be called by rtc_resume(), and allows
1076 * a suspend offset to be injected into the timekeeping values.
1078 void timekeeping_inject_sleeptime(struct timespec
*delta
)
1080 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1081 struct timespec64 tmp
;
1082 unsigned long flags
;
1085 * Make sure we don't set the clock twice, as timekeeping_resume()
1088 if (has_persistent_clock())
1091 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1092 write_seqcount_begin(&tk_core
.seq
);
1094 timekeeping_forward_now(tk
);
1096 tmp
= timespec_to_timespec64(*delta
);
1097 __timekeeping_inject_sleeptime(tk
, &tmp
);
1099 timekeeping_update(tk
, TK_CLEAR_NTP
| TK_MIRROR
| TK_CLOCK_WAS_SET
);
1101 write_seqcount_end(&tk_core
.seq
);
1102 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1104 /* signal hrtimers about time change */
1109 * timekeeping_resume - Resumes the generic timekeeping subsystem.
1111 * This is for the generic clocksource timekeeping.
1112 * xtime/wall_to_monotonic/jiffies/etc are
1113 * still managed by arch specific suspend/resume code.
1115 static void timekeeping_resume(void)
1117 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1118 struct clocksource
*clock
= tk
->tkr
.clock
;
1119 unsigned long flags
;
1120 struct timespec64 ts_new
, ts_delta
;
1121 struct timespec tmp
;
1122 cycle_t cycle_now
, cycle_delta
;
1123 bool suspendtime_found
= false;
1125 read_persistent_clock(&tmp
);
1126 ts_new
= timespec_to_timespec64(tmp
);
1128 clockevents_resume();
1129 clocksource_resume();
1131 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1132 write_seqcount_begin(&tk_core
.seq
);
1135 * After system resumes, we need to calculate the suspended time and
1136 * compensate it for the OS time. There are 3 sources that could be
1137 * used: Nonstop clocksource during suspend, persistent clock and rtc
1140 * One specific platform may have 1 or 2 or all of them, and the
1141 * preference will be:
1142 * suspend-nonstop clocksource -> persistent clock -> rtc
1143 * The less preferred source will only be tried if there is no better
1144 * usable source. The rtc part is handled separately in rtc core code.
1146 cycle_now
= tk
->tkr
.read(clock
);
1147 if ((clock
->flags
& CLOCK_SOURCE_SUSPEND_NONSTOP
) &&
1148 cycle_now
> tk
->tkr
.cycle_last
) {
1149 u64 num
, max
= ULLONG_MAX
;
1150 u32 mult
= clock
->mult
;
1151 u32 shift
= clock
->shift
;
1154 cycle_delta
= clocksource_delta(cycle_now
, tk
->tkr
.cycle_last
,
1158 * "cycle_delta * mutl" may cause 64 bits overflow, if the
1159 * suspended time is too long. In that case we need do the
1160 * 64 bits math carefully
1163 if (cycle_delta
> max
) {
1164 num
= div64_u64(cycle_delta
, max
);
1165 nsec
= (((u64
) max
* mult
) >> shift
) * num
;
1166 cycle_delta
-= num
* max
;
1168 nsec
+= ((u64
) cycle_delta
* mult
) >> shift
;
1170 ts_delta
= ns_to_timespec64(nsec
);
1171 suspendtime_found
= true;
1172 } else if (timespec64_compare(&ts_new
, &timekeeping_suspend_time
) > 0) {
1173 ts_delta
= timespec64_sub(ts_new
, timekeeping_suspend_time
);
1174 suspendtime_found
= true;
1177 if (suspendtime_found
)
1178 __timekeeping_inject_sleeptime(tk
, &ts_delta
);
1180 /* Re-base the last cycle value */
1181 tk
->tkr
.cycle_last
= cycle_now
;
1183 timekeeping_suspended
= 0;
1184 timekeeping_update(tk
, TK_MIRROR
| TK_CLOCK_WAS_SET
);
1185 write_seqcount_end(&tk_core
.seq
);
1186 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1188 touch_softlockup_watchdog();
1190 clockevents_notify(CLOCK_EVT_NOTIFY_RESUME
, NULL
);
1192 /* Resume hrtimers */
1196 static int timekeeping_suspend(void)
1198 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1199 unsigned long flags
;
1200 struct timespec64 delta
, delta_delta
;
1201 static struct timespec64 old_delta
;
1202 struct timespec tmp
;
1204 read_persistent_clock(&tmp
);
1205 timekeeping_suspend_time
= timespec_to_timespec64(tmp
);
1208 * On some systems the persistent_clock can not be detected at
1209 * timekeeping_init by its return value, so if we see a valid
1210 * value returned, update the persistent_clock_exists flag.
1212 if (timekeeping_suspend_time
.tv_sec
|| timekeeping_suspend_time
.tv_nsec
)
1213 persistent_clock_exist
= true;
1215 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1216 write_seqcount_begin(&tk_core
.seq
);
1217 timekeeping_forward_now(tk
);
1218 timekeeping_suspended
= 1;
1221 * To avoid drift caused by repeated suspend/resumes,
1222 * which each can add ~1 second drift error,
1223 * try to compensate so the difference in system time
1224 * and persistent_clock time stays close to constant.
1226 delta
= timespec64_sub(tk_xtime(tk
), timekeeping_suspend_time
);
1227 delta_delta
= timespec64_sub(delta
, old_delta
);
1228 if (abs(delta_delta
.tv_sec
) >= 2) {
1230 * if delta_delta is too large, assume time correction
1231 * has occured and set old_delta to the current delta.
1235 /* Otherwise try to adjust old_system to compensate */
1236 timekeeping_suspend_time
=
1237 timespec64_add(timekeeping_suspend_time
, delta_delta
);
1240 timekeeping_update(tk
, TK_MIRROR
);
1241 write_seqcount_end(&tk_core
.seq
);
1242 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1244 clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND
, NULL
);
1245 clocksource_suspend();
1246 clockevents_suspend();
1251 /* sysfs resume/suspend bits for timekeeping */
1252 static struct syscore_ops timekeeping_syscore_ops
= {
1253 .resume
= timekeeping_resume
,
1254 .suspend
= timekeeping_suspend
,
1257 static int __init
timekeeping_init_ops(void)
1259 register_syscore_ops(&timekeeping_syscore_ops
);
1262 device_initcall(timekeeping_init_ops
);
1265 * Apply a multiplier adjustment to the timekeeper
1267 static __always_inline
void timekeeping_apply_adjustment(struct timekeeper
*tk
,
1272 s64 interval
= tk
->cycle_interval
;
1276 mult_adj
= -mult_adj
;
1277 interval
= -interval
;
1280 mult_adj
<<= adj_scale
;
1281 interval
<<= adj_scale
;
1282 offset
<<= adj_scale
;
1285 * So the following can be confusing.
1287 * To keep things simple, lets assume mult_adj == 1 for now.
1289 * When mult_adj != 1, remember that the interval and offset values
1290 * have been appropriately scaled so the math is the same.
1292 * The basic idea here is that we're increasing the multiplier
1293 * by one, this causes the xtime_interval to be incremented by
1294 * one cycle_interval. This is because:
1295 * xtime_interval = cycle_interval * mult
1296 * So if mult is being incremented by one:
1297 * xtime_interval = cycle_interval * (mult + 1)
1299 * xtime_interval = (cycle_interval * mult) + cycle_interval
1300 * Which can be shortened to:
1301 * xtime_interval += cycle_interval
1303 * So offset stores the non-accumulated cycles. Thus the current
1304 * time (in shifted nanoseconds) is:
1305 * now = (offset * adj) + xtime_nsec
1306 * Now, even though we're adjusting the clock frequency, we have
1307 * to keep time consistent. In other words, we can't jump back
1308 * in time, and we also want to avoid jumping forward in time.
1310 * So given the same offset value, we need the time to be the same
1311 * both before and after the freq adjustment.
1312 * now = (offset * adj_1) + xtime_nsec_1
1313 * now = (offset * adj_2) + xtime_nsec_2
1315 * (offset * adj_1) + xtime_nsec_1 =
1316 * (offset * adj_2) + xtime_nsec_2
1320 * (offset * adj_1) + xtime_nsec_1 =
1321 * (offset * (adj_1+1)) + xtime_nsec_2
1322 * (offset * adj_1) + xtime_nsec_1 =
1323 * (offset * adj_1) + offset + xtime_nsec_2
1324 * Canceling the sides:
1325 * xtime_nsec_1 = offset + xtime_nsec_2
1327 * xtime_nsec_2 = xtime_nsec_1 - offset
1328 * Which simplfies to:
1329 * xtime_nsec -= offset
1331 * XXX - TODO: Doc ntp_error calculation.
1333 tk
->tkr
.mult
+= mult_adj
;
1334 tk
->xtime_interval
+= interval
;
1335 tk
->tkr
.xtime_nsec
-= offset
;
1336 tk
->ntp_error
-= (interval
- offset
) << tk
->ntp_error_shift
;
1340 * Calculate the multiplier adjustment needed to match the frequency
1343 static __always_inline
void timekeeping_freqadjust(struct timekeeper
*tk
,
1346 s64 interval
= tk
->cycle_interval
;
1347 s64 xinterval
= tk
->xtime_interval
;
1352 /* Remove any current error adj from freq calculation */
1353 if (tk
->ntp_err_mult
)
1354 xinterval
-= tk
->cycle_interval
;
1356 tk
->ntp_tick
= ntp_tick_length();
1358 /* Calculate current error per tick */
1359 tick_error
= ntp_tick_length() >> tk
->ntp_error_shift
;
1360 tick_error
-= (xinterval
+ tk
->xtime_remainder
);
1362 /* Don't worry about correcting it if its small */
1363 if (likely((tick_error
>= 0) && (tick_error
<= interval
)))
1366 /* preserve the direction of correction */
1367 negative
= (tick_error
< 0);
1369 /* Sort out the magnitude of the correction */
1370 tick_error
= abs(tick_error
);
1371 for (adj
= 0; tick_error
> interval
; adj
++)
1374 /* scale the corrections */
1375 timekeeping_apply_adjustment(tk
, offset
, negative
, adj
);
1379 * Adjust the timekeeper's multiplier to the correct frequency
1380 * and also to reduce the accumulated error value.
1382 static void timekeeping_adjust(struct timekeeper
*tk
, s64 offset
)
1384 /* Correct for the current frequency error */
1385 timekeeping_freqadjust(tk
, offset
);
1387 /* Next make a small adjustment to fix any cumulative error */
1388 if (!tk
->ntp_err_mult
&& (tk
->ntp_error
> 0)) {
1389 tk
->ntp_err_mult
= 1;
1390 timekeeping_apply_adjustment(tk
, offset
, 0, 0);
1391 } else if (tk
->ntp_err_mult
&& (tk
->ntp_error
<= 0)) {
1392 /* Undo any existing error adjustment */
1393 timekeeping_apply_adjustment(tk
, offset
, 1, 0);
1394 tk
->ntp_err_mult
= 0;
1397 if (unlikely(tk
->tkr
.clock
->maxadj
&&
1398 (tk
->tkr
.mult
> tk
->tkr
.clock
->mult
+ tk
->tkr
.clock
->maxadj
))) {
1399 printk_once(KERN_WARNING
1400 "Adjusting %s more than 11%% (%ld vs %ld)\n",
1401 tk
->tkr
.clock
->name
, (long)tk
->tkr
.mult
,
1402 (long)tk
->tkr
.clock
->mult
+ tk
->tkr
.clock
->maxadj
);
1406 * It may be possible that when we entered this function, xtime_nsec
1407 * was very small. Further, if we're slightly speeding the clocksource
1408 * in the code above, its possible the required corrective factor to
1409 * xtime_nsec could cause it to underflow.
1411 * Now, since we already accumulated the second, cannot simply roll
1412 * the accumulated second back, since the NTP subsystem has been
1413 * notified via second_overflow. So instead we push xtime_nsec forward
1414 * by the amount we underflowed, and add that amount into the error.
1416 * We'll correct this error next time through this function, when
1417 * xtime_nsec is not as small.
1419 if (unlikely((s64
)tk
->tkr
.xtime_nsec
< 0)) {
1420 s64 neg
= -(s64
)tk
->tkr
.xtime_nsec
;
1421 tk
->tkr
.xtime_nsec
= 0;
1422 tk
->ntp_error
+= neg
<< tk
->ntp_error_shift
;
1427 * accumulate_nsecs_to_secs - Accumulates nsecs into secs
1429 * Helper function that accumulates a the nsecs greater then a second
1430 * from the xtime_nsec field to the xtime_secs field.
1431 * It also calls into the NTP code to handle leapsecond processing.
1434 static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper
*tk
)
1436 u64 nsecps
= (u64
)NSEC_PER_SEC
<< tk
->tkr
.shift
;
1437 unsigned int clock_set
= 0;
1439 while (tk
->tkr
.xtime_nsec
>= nsecps
) {
1442 tk
->tkr
.xtime_nsec
-= nsecps
;
1445 /* Figure out if its a leap sec and apply if needed */
1446 leap
= second_overflow(tk
->xtime_sec
);
1447 if (unlikely(leap
)) {
1448 struct timespec64 ts
;
1450 tk
->xtime_sec
+= leap
;
1454 tk_set_wall_to_mono(tk
,
1455 timespec64_sub(tk
->wall_to_monotonic
, ts
));
1457 __timekeeping_set_tai_offset(tk
, tk
->tai_offset
- leap
);
1459 clock_set
= TK_CLOCK_WAS_SET
;
1466 * logarithmic_accumulation - shifted accumulation of cycles
1468 * This functions accumulates a shifted interval of cycles into
1469 * into a shifted interval nanoseconds. Allows for O(log) accumulation
1472 * Returns the unconsumed cycles.
1474 static cycle_t
logarithmic_accumulation(struct timekeeper
*tk
, cycle_t offset
,
1476 unsigned int *clock_set
)
1478 cycle_t interval
= tk
->cycle_interval
<< shift
;
1481 /* If the offset is smaller then a shifted interval, do nothing */
1482 if (offset
< interval
)
1485 /* Accumulate one shifted interval */
1487 tk
->tkr
.cycle_last
+= interval
;
1489 tk
->tkr
.xtime_nsec
+= tk
->xtime_interval
<< shift
;
1490 *clock_set
|= accumulate_nsecs_to_secs(tk
);
1492 /* Accumulate raw time */
1493 raw_nsecs
= (u64
)tk
->raw_interval
<< shift
;
1494 raw_nsecs
+= tk
->raw_time
.tv_nsec
;
1495 if (raw_nsecs
>= NSEC_PER_SEC
) {
1496 u64 raw_secs
= raw_nsecs
;
1497 raw_nsecs
= do_div(raw_secs
, NSEC_PER_SEC
);
1498 tk
->raw_time
.tv_sec
+= raw_secs
;
1500 tk
->raw_time
.tv_nsec
= raw_nsecs
;
1502 /* Accumulate error between NTP and clock interval */
1503 tk
->ntp_error
+= tk
->ntp_tick
<< shift
;
1504 tk
->ntp_error
-= (tk
->xtime_interval
+ tk
->xtime_remainder
) <<
1505 (tk
->ntp_error_shift
+ shift
);
1511 * update_wall_time - Uses the current clocksource to increment the wall time
1514 void update_wall_time(void)
1516 struct timekeeper
*real_tk
= &tk_core
.timekeeper
;
1517 struct timekeeper
*tk
= &shadow_timekeeper
;
1519 int shift
= 0, maxshift
;
1520 unsigned int clock_set
= 0;
1521 unsigned long flags
;
1523 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1525 /* Make sure we're fully resumed: */
1526 if (unlikely(timekeeping_suspended
))
1529 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
1530 offset
= real_tk
->cycle_interval
;
1532 offset
= clocksource_delta(tk
->tkr
.read(tk
->tkr
.clock
),
1533 tk
->tkr
.cycle_last
, tk
->tkr
.mask
);
1536 /* Check if there's really nothing to do */
1537 if (offset
< real_tk
->cycle_interval
)
1541 * With NO_HZ we may have to accumulate many cycle_intervals
1542 * (think "ticks") worth of time at once. To do this efficiently,
1543 * we calculate the largest doubling multiple of cycle_intervals
1544 * that is smaller than the offset. We then accumulate that
1545 * chunk in one go, and then try to consume the next smaller
1548 shift
= ilog2(offset
) - ilog2(tk
->cycle_interval
);
1549 shift
= max(0, shift
);
1550 /* Bound shift to one less than what overflows tick_length */
1551 maxshift
= (64 - (ilog2(ntp_tick_length())+1)) - 1;
1552 shift
= min(shift
, maxshift
);
1553 while (offset
>= tk
->cycle_interval
) {
1554 offset
= logarithmic_accumulation(tk
, offset
, shift
,
1556 if (offset
< tk
->cycle_interval
<<shift
)
1560 /* correct the clock when NTP error is too big */
1561 timekeeping_adjust(tk
, offset
);
1564 * XXX This can be killed once everyone converts
1565 * to the new update_vsyscall.
1567 old_vsyscall_fixup(tk
);
1570 * Finally, make sure that after the rounding
1571 * xtime_nsec isn't larger than NSEC_PER_SEC
1573 clock_set
|= accumulate_nsecs_to_secs(tk
);
1575 write_seqcount_begin(&tk_core
.seq
);
1577 * Update the real timekeeper.
1579 * We could avoid this memcpy by switching pointers, but that
1580 * requires changes to all other timekeeper usage sites as
1581 * well, i.e. move the timekeeper pointer getter into the
1582 * spinlocked/seqcount protected sections. And we trade this
1583 * memcpy under the tk_core.seq against one before we start
1586 memcpy(real_tk
, tk
, sizeof(*tk
));
1587 timekeeping_update(real_tk
, clock_set
);
1588 write_seqcount_end(&tk_core
.seq
);
1590 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1592 /* Have to call _delayed version, since in irq context*/
1593 clock_was_set_delayed();
1597 * getboottime - Return the real time of system boot.
1598 * @ts: pointer to the timespec to be set
1600 * Returns the wall-time of boot in a timespec.
1602 * This is based on the wall_to_monotonic offset and the total suspend
1603 * time. Calls to settimeofday will affect the value returned (which
1604 * basically means that however wrong your real time clock is at boot time,
1605 * you get the right time here).
1607 void getboottime(struct timespec
*ts
)
1609 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1610 ktime_t t
= ktime_sub(tk
->offs_real
, tk
->offs_boot
);
1612 *ts
= ktime_to_timespec(t
);
1614 EXPORT_SYMBOL_GPL(getboottime
);
1616 unsigned long get_seconds(void)
1618 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1620 return tk
->xtime_sec
;
1622 EXPORT_SYMBOL(get_seconds
);
1624 struct timespec
__current_kernel_time(void)
1626 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1628 return timespec64_to_timespec(tk_xtime(tk
));
1631 struct timespec
current_kernel_time(void)
1633 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1634 struct timespec64 now
;
1638 seq
= read_seqcount_begin(&tk_core
.seq
);
1641 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1643 return timespec64_to_timespec(now
);
1645 EXPORT_SYMBOL(current_kernel_time
);
1647 struct timespec
get_monotonic_coarse(void)
1649 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1650 struct timespec64 now
, mono
;
1654 seq
= read_seqcount_begin(&tk_core
.seq
);
1657 mono
= tk
->wall_to_monotonic
;
1658 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1660 set_normalized_timespec64(&now
, now
.tv_sec
+ mono
.tv_sec
,
1661 now
.tv_nsec
+ mono
.tv_nsec
);
1663 return timespec64_to_timespec(now
);
1667 * Must hold jiffies_lock
1669 void do_timer(unsigned long ticks
)
1671 jiffies_64
+= ticks
;
1672 calc_global_load(ticks
);
1676 * ktime_get_update_offsets_tick - hrtimer helper
1677 * @offs_real: pointer to storage for monotonic -> realtime offset
1678 * @offs_boot: pointer to storage for monotonic -> boottime offset
1679 * @offs_tai: pointer to storage for monotonic -> clock tai offset
1681 * Returns monotonic time at last tick and various offsets
1683 ktime_t
ktime_get_update_offsets_tick(ktime_t
*offs_real
, ktime_t
*offs_boot
,
1686 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1692 seq
= read_seqcount_begin(&tk_core
.seq
);
1694 base
= tk
->tkr
.base_mono
;
1695 nsecs
= tk
->tkr
.xtime_nsec
>> tk
->tkr
.shift
;
1697 *offs_real
= tk
->offs_real
;
1698 *offs_boot
= tk
->offs_boot
;
1699 *offs_tai
= tk
->offs_tai
;
1700 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1702 return ktime_add_ns(base
, nsecs
);
1705 #ifdef CONFIG_HIGH_RES_TIMERS
1707 * ktime_get_update_offsets_now - hrtimer helper
1708 * @offs_real: pointer to storage for monotonic -> realtime offset
1709 * @offs_boot: pointer to storage for monotonic -> boottime offset
1710 * @offs_tai: pointer to storage for monotonic -> clock tai offset
1712 * Returns current monotonic time and updates the offsets
1713 * Called from hrtimer_interrupt() or retrigger_next_event()
1715 ktime_t
ktime_get_update_offsets_now(ktime_t
*offs_real
, ktime_t
*offs_boot
,
1718 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1724 seq
= read_seqcount_begin(&tk_core
.seq
);
1726 base
= tk
->tkr
.base_mono
;
1727 nsecs
= timekeeping_get_ns(&tk
->tkr
);
1729 *offs_real
= tk
->offs_real
;
1730 *offs_boot
= tk
->offs_boot
;
1731 *offs_tai
= tk
->offs_tai
;
1732 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1734 return ktime_add_ns(base
, nsecs
);
1739 * do_adjtimex() - Accessor function to NTP __do_adjtimex function
1741 int do_adjtimex(struct timex
*txc
)
1743 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1744 unsigned long flags
;
1745 struct timespec64 ts
;
1749 /* Validate the data before disabling interrupts */
1750 ret
= ntp_validate_timex(txc
);
1754 if (txc
->modes
& ADJ_SETOFFSET
) {
1755 struct timespec delta
;
1756 delta
.tv_sec
= txc
->time
.tv_sec
;
1757 delta
.tv_nsec
= txc
->time
.tv_usec
;
1758 if (!(txc
->modes
& ADJ_NANO
))
1759 delta
.tv_nsec
*= 1000;
1760 ret
= timekeeping_inject_offset(&delta
);
1765 getnstimeofday64(&ts
);
1767 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1768 write_seqcount_begin(&tk_core
.seq
);
1770 orig_tai
= tai
= tk
->tai_offset
;
1771 ret
= __do_adjtimex(txc
, &ts
, &tai
);
1773 if (tai
!= orig_tai
) {
1774 __timekeeping_set_tai_offset(tk
, tai
);
1775 timekeeping_update(tk
, TK_MIRROR
| TK_CLOCK_WAS_SET
);
1777 write_seqcount_end(&tk_core
.seq
);
1778 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1780 if (tai
!= orig_tai
)
1783 ntp_notify_cmos_timer();
1788 #ifdef CONFIG_NTP_PPS
1790 * hardpps() - Accessor function to NTP __hardpps function
1792 void hardpps(const struct timespec
*phase_ts
, const struct timespec
*raw_ts
)
1794 unsigned long flags
;
1796 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1797 write_seqcount_begin(&tk_core
.seq
);
1799 __hardpps(phase_ts
, raw_ts
);
1801 write_seqcount_end(&tk_core
.seq
);
1802 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1804 EXPORT_SYMBOL(hardpps
);
1808 * xtime_update() - advances the timekeeping infrastructure
1809 * @ticks: number of ticks, that have elapsed since the last call.
1811 * Must be called with interrupts disabled.
1813 void xtime_update(unsigned long ticks
)
1815 write_seqlock(&jiffies_lock
);
1817 write_sequnlock(&jiffies_lock
);