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)
341 struct timespec xt, wm;
343 xt = timespec64_to_timespec(tk_xtime(tk));
344 wm = timespec64_to_timespec(tk->wall_to_monotonic);
345 update_vsyscall_old(&xt, &wm, tk->tkr.clock, tk->tkr.mult,
349 static inline void old_vsyscall_fixup(struct timekeeper *tk)
354 * Store only full nanoseconds into xtime_nsec after rounding
355 * it up and add the remainder to the error difference.
356 * XXX - This is necessary to avoid small 1ns inconsistnecies caused
357 * by truncating the remainder in vsyscalls. However, it causes
358 * additional work to be done in timekeeping_adjust(). Once
359 * the vsyscall implementations are converted to use xtime_nsec
360 * (shifted nanoseconds), and CONFIG_GENERIC_TIME_VSYSCALL_OLD
361 * users are removed, this can be killed.
363 remainder = tk->tkr.xtime_nsec & ((1ULL << tk->tkr.shift) - 1);
364 tk->tkr.xtime_nsec -= remainder;
365 tk->tkr.xtime_nsec += 1ULL << tk->tkr.shift;
366 tk->ntp_error += remainder << tk->ntp_error_shift;
367 tk->ntp_error -= (1ULL << tk->tkr.shift) << tk->ntp_error_shift;
370 #define old_vsyscall_fixup(tk)
373 static RAW_NOTIFIER_HEAD(pvclock_gtod_chain);
375 static void update_pvclock_gtod(struct timekeeper *tk, bool was_set)
377 raw_notifier_call_chain(&pvclock_gtod_chain, was_set, tk);
381 * pvclock_gtod_register_notifier - register a pvclock timedata update listener
383 int pvclock_gtod_register_notifier(struct notifier_block *nb)
385 struct timekeeper *tk = &tk_core.timekeeper;
389 raw_spin_lock_irqsave(&timekeeper_lock, flags);
390 ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb);
391 update_pvclock_gtod(tk, true);
392 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
396 EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier);
399 * pvclock_gtod_unregister_notifier - unregister a pvclock
400 * timedata update listener
402 int pvclock_gtod_unregister_notifier(struct notifier_block *nb)
407 raw_spin_lock_irqsave(&timekeeper_lock, flags);
408 ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb);
409 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
413 EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier);
416 * Update the ktime_t based scalar nsec members of the timekeeper
418 static inline void tk_update_ktime_data(struct timekeeper *tk)
423 * The xtime based monotonic readout is:
424 * nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();
425 * The ktime based monotonic readout is:
426 * nsec = base_mono + now();
427 * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec
429 nsec = (s64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec);
430 nsec *= NSEC_PER_SEC;
431 nsec += tk->wall_to_monotonic.tv_nsec;
432 tk->tkr.base_mono = ns_to_ktime(nsec);
434 /* Update the monotonic raw base */
435 tk->base_raw = timespec64_to_ktime(tk->raw_time);
438 /* must hold timekeeper_lock */
439 static void timekeeping_update(struct timekeeper *tk, unsigned int action)
441 if (action & TK_CLEAR_NTP) {
446 tk_update_ktime_data(tk);
449 update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);
451 if (action & TK_MIRROR)
452 memcpy(&shadow_timekeeper, &tk_core.timekeeper,
453 sizeof(tk_core.timekeeper));
455 update_fast_timekeeper(tk);
459 * timekeeping_forward_now - update clock to the current time
461 * Forward the current clock to update its state since the last call to
462 * update_wall_time(). This is useful before significant clock changes,
463 * as it avoids having to deal with this time offset explicitly.
465 static void timekeeping_forward_now(struct timekeeper *tk)
467 struct clocksource *clock = tk->tkr.clock;
468 cycle_t cycle_now, delta;
471 cycle_now = tk->tkr.read(clock);
472 delta = clocksource_delta(cycle_now, tk->tkr.cycle_last, tk->tkr.mask);
473 tk->tkr.cycle_last = cycle_now;
475 tk->tkr.xtime_nsec += delta * tk->tkr.mult;
477 /* If arch requires, add in get_arch_timeoffset() */
478 tk->tkr.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr.shift;
480 tk_normalize_xtime(tk);
482 nsec = clocksource_cyc2ns(delta, clock->mult, clock->shift);
483 timespec64_add_ns(&tk->raw_time, nsec);
487 * __getnstimeofday64 - Returns the time of day in a timespec64.
488 * @ts: pointer to the timespec to be set
490 * Updates the time of day in the timespec.
491 * Returns 0 on success, or -ve when suspended (timespec will be undefined).
493 int __getnstimeofday64(struct timespec64 *ts)
495 struct timekeeper *tk = &tk_core.timekeeper;
500 seq = read_seqcount_begin(&tk_core.seq);
502 ts->tv_sec = tk->xtime_sec;
503 nsecs = timekeeping_get_ns(&tk->tkr);
505 } while (read_seqcount_retry(&tk_core.seq, seq));
508 timespec64_add_ns(ts, nsecs);
511 * Do not bail out early, in case there were callers still using
512 * the value, even in the face of the WARN_ON.
514 if (unlikely(timekeeping_suspended))
518 EXPORT_SYMBOL(__getnstimeofday64);
521 * getnstimeofday64 - Returns the time of day in a timespec64.
522 * @ts: pointer to the timespec to be set
524 * Returns the time of day in a timespec (WARN if suspended).
526 void getnstimeofday64(struct timespec64 *ts)
528 WARN_ON(__getnstimeofday64(ts));
530 EXPORT_SYMBOL(getnstimeofday64);
532 ktime_t ktime_get(void)
534 struct timekeeper *tk = &tk_core.timekeeper;
539 WARN_ON(timekeeping_suspended);
542 seq = read_seqcount_begin(&tk_core.seq);
543 base = tk->tkr.base_mono;
544 nsecs = timekeeping_get_ns(&tk->tkr);
546 } while (read_seqcount_retry(&tk_core.seq, seq));
548 return ktime_add_ns(base, nsecs);
550 EXPORT_SYMBOL_GPL(ktime_get);
552 static ktime_t *offsets[TK_OFFS_MAX] = {
553 [TK_OFFS_REAL] = &tk_core.timekeeper.offs_real,
554 [TK_OFFS_BOOT] = &tk_core.timekeeper.offs_boot,
555 [TK_OFFS_TAI] = &tk_core.timekeeper.offs_tai,
558 ktime_t ktime_get_with_offset(enum tk_offsets offs)
560 struct timekeeper *tk = &tk_core.timekeeper;
562 ktime_t base, *offset = offsets[offs];
565 WARN_ON(timekeeping_suspended);
568 seq = read_seqcount_begin(&tk_core.seq);
569 base = ktime_add(tk->tkr.base_mono, *offset);
570 nsecs = timekeeping_get_ns(&tk->tkr);
572 } while (read_seqcount_retry(&tk_core.seq, seq));
574 return ktime_add_ns(base, nsecs);
577 EXPORT_SYMBOL_GPL(ktime_get_with_offset);
580 * ktime_mono_to_any() - convert mononotic time to any other time
581 * @tmono: time to convert.
582 * @offs: which offset to use
584 ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs)
586 ktime_t *offset = offsets[offs];
591 seq = read_seqcount_begin(&tk_core.seq);
592 tconv = ktime_add(tmono, *offset);
593 } while (read_seqcount_retry(&tk_core.seq, seq));
597 EXPORT_SYMBOL_GPL(ktime_mono_to_any);
600 * ktime_get_raw - Returns the raw monotonic time in ktime_t format
602 ktime_t ktime_get_raw(void)
604 struct timekeeper *tk = &tk_core.timekeeper;
610 seq = read_seqcount_begin(&tk_core.seq);
612 nsecs = timekeeping_get_ns_raw(tk);
614 } while (read_seqcount_retry(&tk_core.seq, seq));
616 return ktime_add_ns(base, nsecs);
618 EXPORT_SYMBOL_GPL(ktime_get_raw);
621 * ktime_get_ts64 - get the monotonic clock in timespec64 format
622 * @ts: pointer to timespec variable
624 * The function calculates the monotonic clock from the realtime
625 * clock and the wall_to_monotonic offset and stores the result
626 * in normalized timespec format in the variable pointed to by @ts.
628 void ktime_get_ts64(struct timespec64 *ts)
630 struct timekeeper *tk = &tk_core.timekeeper;
631 struct timespec64 tomono;
635 WARN_ON(timekeeping_suspended);
638 seq = read_seqcount_begin(&tk_core.seq);
639 ts->tv_sec = tk->xtime_sec;
640 nsec = timekeeping_get_ns(&tk->tkr);
641 tomono = tk->wall_to_monotonic;
643 } while (read_seqcount_retry(&tk_core.seq, seq));
645 ts->tv_sec += tomono.tv_sec;
647 timespec64_add_ns(ts, nsec + tomono.tv_nsec);
649 EXPORT_SYMBOL_GPL(ktime_get_ts64);
651 #ifdef CONFIG_NTP_PPS
654 * getnstime_raw_and_real - get day and raw monotonic time in timespec format
655 * @ts_raw: pointer to the timespec to be set to raw monotonic time
656 * @ts_real: pointer to the timespec to be set to the time of day
658 * This function reads both the time of day and raw monotonic time at the
659 * same time atomically and stores the resulting timestamps in timespec
662 void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real)
664 struct timekeeper *tk = &tk_core.timekeeper;
666 s64 nsecs_raw, nsecs_real;
668 WARN_ON_ONCE(timekeeping_suspended);
671 seq = read_seqcount_begin(&tk_core.seq);
673 *ts_raw = timespec64_to_timespec(tk->raw_time);
674 ts_real->tv_sec = tk->xtime_sec;
675 ts_real->tv_nsec = 0;
677 nsecs_raw = timekeeping_get_ns_raw(tk);
678 nsecs_real = timekeeping_get_ns(&tk->tkr);
680 } while (read_seqcount_retry(&tk_core.seq, seq));
682 timespec_add_ns(ts_raw, nsecs_raw);
683 timespec_add_ns(ts_real, nsecs_real);
685 EXPORT_SYMBOL(getnstime_raw_and_real);
687 #endif /* CONFIG_NTP_PPS */
690 * do_gettimeofday - Returns the time of day in a timeval
691 * @tv: pointer to the timeval to be set
693 * NOTE: Users should be converted to using getnstimeofday()
695 void do_gettimeofday(struct timeval *tv)
697 struct timespec64 now;
699 getnstimeofday64(&now);
700 tv->tv_sec = now.tv_sec;
701 tv->tv_usec = now.tv_nsec/1000;
703 EXPORT_SYMBOL(do_gettimeofday);
706 * do_settimeofday - Sets the time of day
707 * @tv: pointer to the timespec variable containing the new time
709 * Sets the time of day to the new time and update NTP and notify hrtimers
711 int do_settimeofday(const struct timespec *tv)
713 struct timekeeper *tk = &tk_core.timekeeper;
714 struct timespec64 ts_delta, xt, tmp;
717 if (!timespec_valid_strict(tv))
720 raw_spin_lock_irqsave(&timekeeper_lock, flags);
721 write_seqcount_begin(&tk_core.seq);
723 timekeeping_forward_now(tk);
726 ts_delta.tv_sec = tv->tv_sec - xt.tv_sec;
727 ts_delta.tv_nsec = tv->tv_nsec - xt.tv_nsec;
729 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));
731 tmp = timespec_to_timespec64(*tv);
732 tk_set_xtime(tk, &tmp);
734 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
736 write_seqcount_end(&tk_core.seq);
737 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
739 /* signal hrtimers about time change */
744 EXPORT_SYMBOL(do_settimeofday);
747 * timekeeping_inject_offset - Adds or subtracts from the current time.
748 * @tv: pointer to the timespec variable containing the offset
750 * Adds or subtracts an offset value from the current time.
752 int timekeeping_inject_offset(struct timespec *ts)
754 struct timekeeper *tk = &tk_core.timekeeper;
756 struct timespec64 ts64, tmp;
759 if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
762 ts64 = timespec_to_timespec64(*ts);
764 raw_spin_lock_irqsave(&timekeeper_lock, flags);
765 write_seqcount_begin(&tk_core.seq);
767 timekeeping_forward_now(tk);
769 /* Make sure the proposed value is valid */
770 tmp = timespec64_add(tk_xtime(tk), ts64);
771 if (!timespec64_valid_strict(&tmp)) {
776 tk_xtime_add(tk, &ts64);
777 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts64));
779 error: /* even if we error out, we forwarded the time, so call update */
780 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
782 write_seqcount_end(&tk_core.seq);
783 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
785 /* signal hrtimers about time change */
790 EXPORT_SYMBOL(timekeeping_inject_offset);
794 * timekeeping_get_tai_offset - Returns current TAI offset from UTC
797 s32 timekeeping_get_tai_offset(void)
799 struct timekeeper *tk = &tk_core.timekeeper;
804 seq = read_seqcount_begin(&tk_core.seq);
805 ret = tk->tai_offset;
806 } while (read_seqcount_retry(&tk_core.seq, seq));
812 * __timekeeping_set_tai_offset - Lock free worker function
815 static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset)
817 tk->tai_offset = tai_offset;
818 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tai_offset, 0));
822 * timekeeping_set_tai_offset - Sets the current TAI offset from UTC
825 void timekeeping_set_tai_offset(s32 tai_offset)
827 struct timekeeper *tk = &tk_core.timekeeper;
830 raw_spin_lock_irqsave(&timekeeper_lock, flags);
831 write_seqcount_begin(&tk_core.seq);
832 __timekeeping_set_tai_offset(tk, tai_offset);
833 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
834 write_seqcount_end(&tk_core.seq);
835 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
840 * change_clocksource - Swaps clocksources if a new one is available
842 * Accumulates current time interval and initializes new clocksource
844 static int change_clocksource(void *data)
846 struct timekeeper *tk = &tk_core.timekeeper;
847 struct clocksource *new, *old;
850 new = (struct clocksource *) data;
852 raw_spin_lock_irqsave(&timekeeper_lock, flags);
853 write_seqcount_begin(&tk_core.seq);
855 timekeeping_forward_now(tk);
857 * If the cs is in module, get a module reference. Succeeds
858 * for built-in code (owner == NULL) as well.
860 if (try_module_get(new->owner)) {
861 if (!new->enable || new->enable(new) == 0) {
863 tk_setup_internals(tk, new);
866 module_put(old->owner);
868 module_put(new->owner);
871 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
873 write_seqcount_end(&tk_core.seq);
874 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
880 * timekeeping_notify - Install a new clock source
881 * @clock: pointer to the clock source
883 * This function is called from clocksource.c after a new, better clock
884 * source has been registered. The caller holds the clocksource_mutex.
886 int timekeeping_notify(struct clocksource *clock)
888 struct timekeeper *tk = &tk_core.timekeeper;
890 if (tk->tkr.clock == clock)
892 stop_machine(change_clocksource, clock, NULL);
894 return tk->tkr.clock == clock ? 0 : -1;
898 * getrawmonotonic - Returns the raw monotonic time in a timespec
899 * @ts: pointer to the timespec to be set
901 * Returns the raw monotonic time (completely un-modified by ntp)
903 void getrawmonotonic(struct timespec *ts)
905 struct timekeeper *tk = &tk_core.timekeeper;
906 struct timespec64 ts64;
911 seq = read_seqcount_begin(&tk_core.seq);
912 nsecs = timekeeping_get_ns_raw(tk);
915 } while (read_seqcount_retry(&tk_core.seq, seq));
917 timespec64_add_ns(&ts64, nsecs);
918 *ts = timespec64_to_timespec(ts64);
920 EXPORT_SYMBOL(getrawmonotonic);
923 * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
925 int timekeeping_valid_for_hres(void)
927 struct timekeeper *tk = &tk_core.timekeeper;
932 seq = read_seqcount_begin(&tk_core.seq);
934 ret = tk->tkr.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
936 } while (read_seqcount_retry(&tk_core.seq, seq));
942 * timekeeping_max_deferment - Returns max time the clocksource can be deferred
944 u64 timekeeping_max_deferment(void)
946 struct timekeeper *tk = &tk_core.timekeeper;
951 seq = read_seqcount_begin(&tk_core.seq);
953 ret = tk->tkr.clock->max_idle_ns;
955 } while (read_seqcount_retry(&tk_core.seq, seq));
961 * read_persistent_clock - Return time from the persistent clock.
963 * Weak dummy function for arches that do not yet support it.
964 * Reads the time from the battery backed persistent clock.
965 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
967 * XXX - Do be sure to remove it once all arches implement it.
969 void __weak read_persistent_clock(struct timespec *ts)
976 * read_boot_clock - Return time of the system start.
978 * Weak dummy function for arches that do not yet support it.
979 * Function to read the exact time the system has been started.
980 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
982 * XXX - Do be sure to remove it once all arches implement it.
984 void __weak read_boot_clock(struct timespec *ts)
991 * timekeeping_init - Initializes the clocksource and common timekeeping values
993 void __init timekeeping_init(void)
995 struct timekeeper *tk = &tk_core.timekeeper;
996 struct clocksource *clock;
998 struct timespec64 now, boot, tmp;
1001 read_persistent_clock(&ts);
1002 now = timespec_to_timespec64(ts);
1003 if (!timespec64_valid_strict(&now)) {
1004 pr_warn("WARNING: Persistent clock returned invalid value!\n"
1005 " Check your CMOS/BIOS settings.\n");
1008 } else if (now.tv_sec || now.tv_nsec)
1009 persistent_clock_exist = true;
1011 read_boot_clock(&ts);
1012 boot = timespec_to_timespec64(ts);
1013 if (!timespec64_valid_strict(&boot)) {
1014 pr_warn("WARNING: Boot clock returned invalid value!\n"
1015 " Check your CMOS/BIOS settings.\n");
1020 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1021 write_seqcount_begin(&tk_core.seq);
1024 clock = clocksource_default_clock();
1026 clock->enable(clock);
1027 tk_setup_internals(tk, clock);
1029 tk_set_xtime(tk, &now);
1030 tk->raw_time.tv_sec = 0;
1031 tk->raw_time.tv_nsec = 0;
1032 tk->base_raw.tv64 = 0;
1033 if (boot.tv_sec == 0 && boot.tv_nsec == 0)
1034 boot = tk_xtime(tk);
1036 set_normalized_timespec64(&tmp, -boot.tv_sec, -boot.tv_nsec);
1037 tk_set_wall_to_mono(tk, tmp);
1039 timekeeping_update(tk, TK_MIRROR);
1041 write_seqcount_end(&tk_core.seq);
1042 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1045 /* time in seconds when suspend began */
1046 static struct timespec64 timekeeping_suspend_time;
1049 * __timekeeping_inject_sleeptime - Internal function to add sleep interval
1050 * @delta: pointer to a timespec delta value
1052 * Takes a timespec offset measuring a suspend interval and properly
1053 * adds the sleep offset to the timekeeping variables.
1055 static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
1056 struct timespec64 *delta)
1058 if (!timespec64_valid_strict(delta)) {
1059 printk_deferred(KERN_WARNING
1060 "__timekeeping_inject_sleeptime: Invalid "
1061 "sleep delta value!\n");
1064 tk_xtime_add(tk, delta);
1065 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *delta));
1066 tk_update_sleep_time(tk, timespec64_to_ktime(*delta));
1067 tk_debug_account_sleep_time(delta);
1071 * timekeeping_inject_sleeptime - Adds suspend interval to timeekeeping values
1072 * @delta: pointer to a timespec delta value
1074 * This hook is for architectures that cannot support read_persistent_clock
1075 * because their RTC/persistent clock is only accessible when irqs are enabled.
1077 * This function should only be called by rtc_resume(), and allows
1078 * a suspend offset to be injected into the timekeeping values.
1080 void timekeeping_inject_sleeptime(struct timespec *delta)
1082 struct timekeeper *tk = &tk_core.timekeeper;
1083 struct timespec64 tmp;
1084 unsigned long flags;
1087 * Make sure we don't set the clock twice, as timekeeping_resume()
1090 if (has_persistent_clock())
1093 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1094 write_seqcount_begin(&tk_core.seq);
1096 timekeeping_forward_now(tk);
1098 tmp = timespec_to_timespec64(*delta);
1099 __timekeeping_inject_sleeptime(tk, &tmp);
1101 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1103 write_seqcount_end(&tk_core.seq);
1104 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1106 /* signal hrtimers about time change */
1111 * timekeeping_resume - Resumes the generic timekeeping subsystem.
1113 * This is for the generic clocksource timekeeping.
1114 * xtime/wall_to_monotonic/jiffies/etc are
1115 * still managed by arch specific suspend/resume code.
1117 static void timekeeping_resume(void)
1119 struct timekeeper *tk = &tk_core.timekeeper;
1120 struct clocksource *clock = tk->tkr.clock;
1121 unsigned long flags;
1122 struct timespec64 ts_new, ts_delta;
1123 struct timespec tmp;
1124 cycle_t cycle_now, cycle_delta;
1125 bool suspendtime_found = false;
1127 read_persistent_clock(&tmp);
1128 ts_new = timespec_to_timespec64(tmp);
1130 clockevents_resume();
1131 clocksource_resume();
1133 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1134 write_seqcount_begin(&tk_core.seq);
1137 * After system resumes, we need to calculate the suspended time and
1138 * compensate it for the OS time. There are 3 sources that could be
1139 * used: Nonstop clocksource during suspend, persistent clock and rtc
1142 * One specific platform may have 1 or 2 or all of them, and the
1143 * preference will be:
1144 * suspend-nonstop clocksource -> persistent clock -> rtc
1145 * The less preferred source will only be tried if there is no better
1146 * usable source. The rtc part is handled separately in rtc core code.
1148 cycle_now = tk->tkr.read(clock);
1149 if ((clock->flags & CLOCK_SOURCE_SUSPEND_NONSTOP) &&
1150 cycle_now > tk->tkr.cycle_last) {
1151 u64 num, max = ULLONG_MAX;
1152 u32 mult = clock->mult;
1153 u32 shift = clock->shift;
1156 cycle_delta = clocksource_delta(cycle_now, tk->tkr.cycle_last,
1160 * "cycle_delta * mutl" may cause 64 bits overflow, if the
1161 * suspended time is too long. In that case we need do the
1162 * 64 bits math carefully
1165 if (cycle_delta > max) {
1166 num = div64_u64(cycle_delta, max);
1167 nsec = (((u64) max * mult) >> shift) * num;
1168 cycle_delta -= num * max;
1170 nsec += ((u64) cycle_delta * mult) >> shift;
1172 ts_delta = ns_to_timespec64(nsec);
1173 suspendtime_found = true;
1174 } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) {
1175 ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time);
1176 suspendtime_found = true;
1179 if (suspendtime_found)
1180 __timekeeping_inject_sleeptime(tk, &ts_delta);
1182 /* Re-base the last cycle value */
1183 tk->tkr.cycle_last = cycle_now;
1185 timekeeping_suspended = 0;
1186 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1187 write_seqcount_end(&tk_core.seq);
1188 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1190 touch_softlockup_watchdog();
1192 clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL);
1194 /* Resume hrtimers */
1198 static int timekeeping_suspend(void)
1200 struct timekeeper *tk = &tk_core.timekeeper;
1201 unsigned long flags;
1202 struct timespec64 delta, delta_delta;
1203 static struct timespec64 old_delta;
1204 struct timespec tmp;
1206 read_persistent_clock(&tmp);
1207 timekeeping_suspend_time = timespec_to_timespec64(tmp);
1210 * On some systems the persistent_clock can not be detected at
1211 * timekeeping_init by its return value, so if we see a valid
1212 * value returned, update the persistent_clock_exists flag.
1214 if (timekeeping_suspend_time.tv_sec || timekeeping_suspend_time.tv_nsec)
1215 persistent_clock_exist = true;
1217 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1218 write_seqcount_begin(&tk_core.seq);
1219 timekeeping_forward_now(tk);
1220 timekeeping_suspended = 1;
1223 * To avoid drift caused by repeated suspend/resumes,
1224 * which each can add ~1 second drift error,
1225 * try to compensate so the difference in system time
1226 * and persistent_clock time stays close to constant.
1228 delta = timespec64_sub(tk_xtime(tk), timekeeping_suspend_time);
1229 delta_delta = timespec64_sub(delta, old_delta);
1230 if (abs(delta_delta.tv_sec) >= 2) {
1232 * if delta_delta is too large, assume time correction
1233 * has occured and set old_delta to the current delta.
1237 /* Otherwise try to adjust old_system to compensate */
1238 timekeeping_suspend_time =
1239 timespec64_add(timekeeping_suspend_time, delta_delta);
1242 timekeeping_update(tk, TK_MIRROR);
1243 write_seqcount_end(&tk_core.seq);
1244 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1246 clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL);
1247 clocksource_suspend();
1248 clockevents_suspend();
1253 /* sysfs resume/suspend bits for timekeeping */
1254 static struct syscore_ops timekeeping_syscore_ops = {
1255 .resume = timekeeping_resume,
1256 .suspend = timekeeping_suspend,
1259 static int __init timekeeping_init_ops(void)
1261 register_syscore_ops(&timekeeping_syscore_ops);
1264 device_initcall(timekeeping_init_ops);
1267 * Apply a multiplier adjustment to the timekeeper
1269 static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk,
1274 s64 interval = tk->cycle_interval;
1278 mult_adj = -mult_adj;
1279 interval = -interval;
1282 mult_adj <<= adj_scale;
1283 interval <<= adj_scale;
1284 offset <<= adj_scale;
1287 * So the following can be confusing.
1289 * To keep things simple, lets assume mult_adj == 1 for now.
1291 * When mult_adj != 1, remember that the interval and offset values
1292 * have been appropriately scaled so the math is the same.
1294 * The basic idea here is that we're increasing the multiplier
1295 * by one, this causes the xtime_interval to be incremented by
1296 * one cycle_interval. This is because:
1297 * xtime_interval = cycle_interval * mult
1298 * So if mult is being incremented by one:
1299 * xtime_interval = cycle_interval * (mult + 1)
1301 * xtime_interval = (cycle_interval * mult) + cycle_interval
1302 * Which can be shortened to:
1303 * xtime_interval += cycle_interval
1305 * So offset stores the non-accumulated cycles. Thus the current
1306 * time (in shifted nanoseconds) is:
1307 * now = (offset * adj) + xtime_nsec
1308 * Now, even though we're adjusting the clock frequency, we have
1309 * to keep time consistent. In other words, we can't jump back
1310 * in time, and we also want to avoid jumping forward in time.
1312 * So given the same offset value, we need the time to be the same
1313 * both before and after the freq adjustment.
1314 * now = (offset * adj_1) + xtime_nsec_1
1315 * now = (offset * adj_2) + xtime_nsec_2
1317 * (offset * adj_1) + xtime_nsec_1 =
1318 * (offset * adj_2) + xtime_nsec_2
1322 * (offset * adj_1) + xtime_nsec_1 =
1323 * (offset * (adj_1+1)) + xtime_nsec_2
1324 * (offset * adj_1) + xtime_nsec_1 =
1325 * (offset * adj_1) + offset + xtime_nsec_2
1326 * Canceling the sides:
1327 * xtime_nsec_1 = offset + xtime_nsec_2
1329 * xtime_nsec_2 = xtime_nsec_1 - offset
1330 * Which simplfies to:
1331 * xtime_nsec -= offset
1333 * XXX - TODO: Doc ntp_error calculation.
1335 tk->tkr.mult += mult_adj;
1336 tk->xtime_interval += interval;
1337 tk->tkr.xtime_nsec -= offset;
1338 tk->ntp_error -= (interval - offset) << tk->ntp_error_shift;
1342 * Calculate the multiplier adjustment needed to match the frequency
1345 static __always_inline void timekeeping_freqadjust(struct timekeeper *tk,
1348 s64 interval = tk->cycle_interval;
1349 s64 xinterval = tk->xtime_interval;
1354 /* Remove any current error adj from freq calculation */
1355 if (tk->ntp_err_mult)
1356 xinterval -= tk->cycle_interval;
1358 tk->ntp_tick = ntp_tick_length();
1360 /* Calculate current error per tick */
1361 tick_error = ntp_tick_length() >> tk->ntp_error_shift;
1362 tick_error -= (xinterval + tk->xtime_remainder);
1364 /* Don't worry about correcting it if its small */
1365 if (likely((tick_error >= 0) && (tick_error <= interval)))
1368 /* preserve the direction of correction */
1369 negative = (tick_error < 0);
1371 /* Sort out the magnitude of the correction */
1372 tick_error = abs(tick_error);
1373 for (adj = 0; tick_error > interval; adj++)
1376 /* scale the corrections */
1377 timekeeping_apply_adjustment(tk, offset, negative, adj);
1381 * Adjust the timekeeper's multiplier to the correct frequency
1382 * and also to reduce the accumulated error value.
1384 static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
1386 /* Correct for the current frequency error */
1387 timekeeping_freqadjust(tk, offset);
1389 /* Next make a small adjustment to fix any cumulative error */
1390 if (!tk->ntp_err_mult && (tk->ntp_error > 0)) {
1391 tk->ntp_err_mult = 1;
1392 timekeeping_apply_adjustment(tk, offset, 0, 0);
1393 } else if (tk->ntp_err_mult && (tk->ntp_error <= 0)) {
1394 /* Undo any existing error adjustment */
1395 timekeeping_apply_adjustment(tk, offset, 1, 0);
1396 tk->ntp_err_mult = 0;
1399 if (unlikely(tk->tkr.clock->maxadj &&
1400 (tk->tkr.mult > tk->tkr.clock->mult + tk->tkr.clock->maxadj))) {
1401 printk_once(KERN_WARNING
1402 "Adjusting %s more than 11%% (%ld vs %ld)\n",
1403 tk->tkr.clock->name, (long)tk->tkr.mult,
1404 (long)tk->tkr.clock->mult + tk->tkr.clock->maxadj);
1408 * It may be possible that when we entered this function, xtime_nsec
1409 * was very small. Further, if we're slightly speeding the clocksource
1410 * in the code above, its possible the required corrective factor to
1411 * xtime_nsec could cause it to underflow.
1413 * Now, since we already accumulated the second, cannot simply roll
1414 * the accumulated second back, since the NTP subsystem has been
1415 * notified via second_overflow. So instead we push xtime_nsec forward
1416 * by the amount we underflowed, and add that amount into the error.
1418 * We'll correct this error next time through this function, when
1419 * xtime_nsec is not as small.
1421 if (unlikely((s64)tk->tkr.xtime_nsec < 0)) {
1422 s64 neg = -(s64)tk->tkr.xtime_nsec;
1423 tk->tkr.xtime_nsec = 0;
1424 tk->ntp_error += neg << tk->ntp_error_shift;
1429 * accumulate_nsecs_to_secs - Accumulates nsecs into secs
1431 * Helper function that accumulates a the nsecs greater then a second
1432 * from the xtime_nsec field to the xtime_secs field.
1433 * It also calls into the NTP code to handle leapsecond processing.
1436 static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper *tk)
1438 u64 nsecps = (u64)NSEC_PER_SEC << tk->tkr.shift;
1439 unsigned int clock_set = 0;
1441 while (tk->tkr.xtime_nsec >= nsecps) {
1444 tk->tkr.xtime_nsec -= nsecps;
1447 /* Figure out if its a leap sec and apply if needed */
1448 leap = second_overflow(tk->xtime_sec);
1449 if (unlikely(leap)) {
1450 struct timespec64 ts;
1452 tk->xtime_sec += leap;
1456 tk_set_wall_to_mono(tk,
1457 timespec64_sub(tk->wall_to_monotonic, ts));
1459 __timekeeping_set_tai_offset(tk, tk->tai_offset - leap);
1461 clock_set = TK_CLOCK_WAS_SET;
1468 * logarithmic_accumulation - shifted accumulation of cycles
1470 * This functions accumulates a shifted interval of cycles into
1471 * into a shifted interval nanoseconds. Allows for O(log) accumulation
1474 * Returns the unconsumed cycles.
1476 static cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset,
1478 unsigned int *clock_set)
1480 cycle_t interval = tk->cycle_interval << shift;
1483 /* If the offset is smaller then a shifted interval, do nothing */
1484 if (offset < interval)
1487 /* Accumulate one shifted interval */
1489 tk->tkr.cycle_last += interval;
1491 tk->tkr.xtime_nsec += tk->xtime_interval << shift;
1492 *clock_set |= accumulate_nsecs_to_secs(tk);
1494 /* Accumulate raw time */
1495 raw_nsecs = (u64)tk->raw_interval << shift;
1496 raw_nsecs += tk->raw_time.tv_nsec;
1497 if (raw_nsecs >= NSEC_PER_SEC) {
1498 u64 raw_secs = raw_nsecs;
1499 raw_nsecs = do_div(raw_secs, NSEC_PER_SEC);
1500 tk->raw_time.tv_sec += raw_secs;
1502 tk->raw_time.tv_nsec = raw_nsecs;
1504 /* Accumulate error between NTP and clock interval */
1505 tk->ntp_error += tk->ntp_tick << shift;
1506 tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) <<
1507 (tk->ntp_error_shift + shift);
1513 * update_wall_time - Uses the current clocksource to increment the wall time
1516 void update_wall_time(void)
1518 struct timekeeper *real_tk = &tk_core.timekeeper;
1519 struct timekeeper *tk = &shadow_timekeeper;
1521 int shift = 0, maxshift;
1522 unsigned int clock_set = 0;
1523 unsigned long flags;
1525 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1527 /* Make sure we're fully resumed: */
1528 if (unlikely(timekeeping_suspended))
1531 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
1532 offset = real_tk->cycle_interval;
1534 offset = clocksource_delta(tk->tkr.read(tk->tkr.clock),
1535 tk->tkr.cycle_last, tk->tkr.mask);
1538 /* Check if there's really nothing to do */
1539 if (offset < real_tk->cycle_interval)
1543 * With NO_HZ we may have to accumulate many cycle_intervals
1544 * (think "ticks") worth of time at once. To do this efficiently,
1545 * we calculate the largest doubling multiple of cycle_intervals
1546 * that is smaller than the offset. We then accumulate that
1547 * chunk in one go, and then try to consume the next smaller
1550 shift = ilog2(offset) - ilog2(tk->cycle_interval);
1551 shift = max(0, shift);
1552 /* Bound shift to one less than what overflows tick_length */
1553 maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1;
1554 shift = min(shift, maxshift);
1555 while (offset >= tk->cycle_interval) {
1556 offset = logarithmic_accumulation(tk, offset, shift,
1558 if (offset < tk->cycle_interval<<shift)
1562 /* correct the clock when NTP error is too big */
1563 timekeeping_adjust(tk, offset);
1566 * XXX This can be killed once everyone converts
1567 * to the new update_vsyscall.
1569 old_vsyscall_fixup(tk);
1572 * Finally, make sure that after the rounding
1573 * xtime_nsec isn't larger than NSEC_PER_SEC
1575 clock_set |= accumulate_nsecs_to_secs(tk);
1577 write_seqcount_begin(&tk_core.seq);
1579 * Update the real timekeeper.
1581 * We could avoid this memcpy by switching pointers, but that
1582 * requires changes to all other timekeeper usage sites as
1583 * well, i.e. move the timekeeper pointer getter into the
1584 * spinlocked/seqcount protected sections. And we trade this
1585 * memcpy under the tk_core.seq against one before we start
1588 memcpy(real_tk, tk, sizeof(*tk));
1589 timekeeping_update(real_tk, clock_set);
1590 write_seqcount_end(&tk_core.seq);
1592 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1594 /* Have to call _delayed version, since in irq context*/
1595 clock_was_set_delayed();
1599 * getboottime - Return the real time of system boot.
1600 * @ts: pointer to the timespec to be set
1602 * Returns the wall-time of boot in a timespec.
1604 * This is based on the wall_to_monotonic offset and the total suspend
1605 * time. Calls to settimeofday will affect the value returned (which
1606 * basically means that however wrong your real time clock is at boot time,
1607 * you get the right time here).
1609 void getboottime(struct timespec *ts)
1611 struct timekeeper *tk = &tk_core.timekeeper;
1612 ktime_t t = ktime_sub(tk->offs_real, tk->offs_boot);
1614 *ts = ktime_to_timespec(t);
1616 EXPORT_SYMBOL_GPL(getboottime);
1618 unsigned long get_seconds(void)
1620 struct timekeeper *tk = &tk_core.timekeeper;
1622 return tk->xtime_sec;
1624 EXPORT_SYMBOL(get_seconds);
1626 struct timespec __current_kernel_time(void)
1628 struct timekeeper *tk = &tk_core.timekeeper;
1630 return timespec64_to_timespec(tk_xtime(tk));
1633 struct timespec current_kernel_time(void)
1635 struct timekeeper *tk = &tk_core.timekeeper;
1636 struct timespec64 now;
1640 seq = read_seqcount_begin(&tk_core.seq);
1643 } while (read_seqcount_retry(&tk_core.seq, seq));
1645 return timespec64_to_timespec(now);
1647 EXPORT_SYMBOL(current_kernel_time);
1649 struct timespec get_monotonic_coarse(void)
1651 struct timekeeper *tk = &tk_core.timekeeper;
1652 struct timespec64 now, mono;
1656 seq = read_seqcount_begin(&tk_core.seq);
1659 mono = tk->wall_to_monotonic;
1660 } while (read_seqcount_retry(&tk_core.seq, seq));
1662 set_normalized_timespec64(&now, now.tv_sec + mono.tv_sec,
1663 now.tv_nsec + mono.tv_nsec);
1665 return timespec64_to_timespec(now);
1669 * Must hold jiffies_lock
1671 void do_timer(unsigned long ticks)
1673 jiffies_64 += ticks;
1674 calc_global_load(ticks);
1678 * ktime_get_update_offsets_tick - hrtimer helper
1679 * @offs_real: pointer to storage for monotonic -> realtime offset
1680 * @offs_boot: pointer to storage for monotonic -> boottime offset
1681 * @offs_tai: pointer to storage for monotonic -> clock tai offset
1683 * Returns monotonic time at last tick and various offsets
1685 ktime_t ktime_get_update_offsets_tick(ktime_t *offs_real, ktime_t *offs_boot,
1688 struct timekeeper *tk = &tk_core.timekeeper;
1694 seq = read_seqcount_begin(&tk_core.seq);
1696 base = tk->tkr.base_mono;
1697 nsecs = tk->tkr.xtime_nsec >> tk->tkr.shift;
1699 *offs_real = tk->offs_real;
1700 *offs_boot = tk->offs_boot;
1701 *offs_tai = tk->offs_tai;
1702 } while (read_seqcount_retry(&tk_core.seq, seq));
1704 return ktime_add_ns(base, nsecs);
1707 #ifdef CONFIG_HIGH_RES_TIMERS
1709 * ktime_get_update_offsets_now - hrtimer helper
1710 * @offs_real: pointer to storage for monotonic -> realtime offset
1711 * @offs_boot: pointer to storage for monotonic -> boottime offset
1712 * @offs_tai: pointer to storage for monotonic -> clock tai offset
1714 * Returns current monotonic time and updates the offsets
1715 * Called from hrtimer_interrupt() or retrigger_next_event()
1717 ktime_t ktime_get_update_offsets_now(ktime_t *offs_real, ktime_t *offs_boot,
1720 struct timekeeper *tk = &tk_core.timekeeper;
1726 seq = read_seqcount_begin(&tk_core.seq);
1728 base = tk->tkr.base_mono;
1729 nsecs = timekeeping_get_ns(&tk->tkr);
1731 *offs_real = tk->offs_real;
1732 *offs_boot = tk->offs_boot;
1733 *offs_tai = tk->offs_tai;
1734 } while (read_seqcount_retry(&tk_core.seq, seq));
1736 return ktime_add_ns(base, nsecs);
1741 * do_adjtimex() - Accessor function to NTP __do_adjtimex function
1743 int do_adjtimex(struct timex *txc)
1745 struct timekeeper *tk = &tk_core.timekeeper;
1746 unsigned long flags;
1747 struct timespec64 ts;
1751 /* Validate the data before disabling interrupts */
1752 ret = ntp_validate_timex(txc);
1756 if (txc->modes & ADJ_SETOFFSET) {
1757 struct timespec delta;
1758 delta.tv_sec = txc->time.tv_sec;
1759 delta.tv_nsec = txc->time.tv_usec;
1760 if (!(txc->modes & ADJ_NANO))
1761 delta.tv_nsec *= 1000;
1762 ret = timekeeping_inject_offset(&delta);
1767 getnstimeofday64(&ts);
1769 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1770 write_seqcount_begin(&tk_core.seq);
1772 orig_tai = tai = tk->tai_offset;
1773 ret = __do_adjtimex(txc, &ts, &tai);
1775 if (tai != orig_tai) {
1776 __timekeeping_set_tai_offset(tk, tai);
1777 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1779 write_seqcount_end(&tk_core.seq);
1780 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1782 if (tai != orig_tai)
1785 ntp_notify_cmos_timer();
1790 #ifdef CONFIG_NTP_PPS
1792 * hardpps() - Accessor function to NTP __hardpps function
1794 void hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts)
1796 unsigned long flags;
1798 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1799 write_seqcount_begin(&tk_core.seq);
1801 __hardpps(phase_ts, raw_ts);
1803 write_seqcount_end(&tk_core.seq);
1804 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1806 EXPORT_SYMBOL(hardpps);
1810 * xtime_update() - advances the timekeeping infrastructure
1811 * @ticks: number of ticks, that have elapsed since the last call.
1813 * Must be called with interrupts disabled.
1815 void xtime_update(unsigned long ticks)
1817 write_seqlock(&jiffies_lock);
1819 write_sequnlock(&jiffies_lock);