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/nmi.h>
18 #include <linux/sched.h>
19 #include <linux/sched/loadavg.h>
20 #include <linux/sched/clock.h>
21 #include <linux/syscore_ops.h>
22 #include <linux/clocksource.h>
23 #include <linux/jiffies.h>
24 #include <linux/time.h>
25 #include <linux/tick.h>
26 #include <linux/stop_machine.h>
27 #include <linux/pvclock_gtod.h>
28 #include <linux/compiler.h>
30 #include "tick-internal.h"
31 #include "ntp_internal.h"
32 #include "timekeeping_internal.h"
34 #define TK_CLEAR_NTP (1 << 0)
35 #define TK_MIRROR (1 << 1)
36 #define TK_CLOCK_WAS_SET (1 << 2)
38 enum timekeeping_adv_mode {
39 /* Update timekeeper when a tick has passed */
42 /* Update timekeeper on a direct frequency change */
47 * The most important data for readout fits into a single 64 byte
52 struct timekeeper timekeeper;
53 } tk_core ____cacheline_aligned = {
54 .seq = SEQCNT_ZERO(tk_core.seq),
57 static DEFINE_RAW_SPINLOCK(timekeeper_lock);
58 static struct timekeeper shadow_timekeeper;
61 * struct tk_fast - NMI safe timekeeper
62 * @seq: Sequence counter for protecting updates. The lowest bit
63 * is the index for the tk_read_base array
64 * @base: tk_read_base array. Access is indexed by the lowest bit of
67 * See @update_fast_timekeeper() below.
71 struct tk_read_base base[2];
74 /* Suspend-time cycles value for halted fast timekeeper. */
75 static u64 cycles_at_suspend;
77 static u64 dummy_clock_read(struct clocksource *cs)
79 return cycles_at_suspend;
82 static struct clocksource dummy_clock = {
83 .read = dummy_clock_read,
86 static struct tk_fast tk_fast_mono ____cacheline_aligned = {
87 .base[0] = { .clock = &dummy_clock, },
88 .base[1] = { .clock = &dummy_clock, },
91 static struct tk_fast tk_fast_raw ____cacheline_aligned = {
92 .base[0] = { .clock = &dummy_clock, },
93 .base[1] = { .clock = &dummy_clock, },
96 /* flag for if timekeeping is suspended */
97 int __read_mostly timekeeping_suspended;
99 static inline void tk_normalize_xtime(struct timekeeper *tk)
101 while (tk->tkr_mono.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_mono.shift)) {
102 tk->tkr_mono.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
105 while (tk->tkr_raw.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_raw.shift)) {
106 tk->tkr_raw.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_raw.shift;
111 static inline struct timespec64 tk_xtime(const struct timekeeper *tk)
113 struct timespec64 ts;
115 ts.tv_sec = tk->xtime_sec;
116 ts.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
120 static void tk_set_xtime(struct timekeeper *tk, const struct timespec64 *ts)
122 tk->xtime_sec = ts->tv_sec;
123 tk->tkr_mono.xtime_nsec = (u64)ts->tv_nsec << tk->tkr_mono.shift;
126 static void tk_xtime_add(struct timekeeper *tk, const struct timespec64 *ts)
128 tk->xtime_sec += ts->tv_sec;
129 tk->tkr_mono.xtime_nsec += (u64)ts->tv_nsec << tk->tkr_mono.shift;
130 tk_normalize_xtime(tk);
133 static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec64 wtm)
135 struct timespec64 tmp;
138 * Verify consistency of: offset_real = -wall_to_monotonic
139 * before modifying anything
141 set_normalized_timespec64(&tmp, -tk->wall_to_monotonic.tv_sec,
142 -tk->wall_to_monotonic.tv_nsec);
143 WARN_ON_ONCE(tk->offs_real != timespec64_to_ktime(tmp));
144 tk->wall_to_monotonic = wtm;
145 set_normalized_timespec64(&tmp, -wtm.tv_sec, -wtm.tv_nsec);
146 tk->offs_real = timespec64_to_ktime(tmp);
147 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tk->tai_offset, 0));
150 static inline void tk_update_sleep_time(struct timekeeper *tk, ktime_t delta)
152 tk->offs_boot = ktime_add(tk->offs_boot, delta);
156 * tk_clock_read - atomic clocksource read() helper
158 * This helper is necessary to use in the read paths because, while the
159 * seqlock ensures we don't return a bad value while structures are updated,
160 * it doesn't protect from potential crashes. There is the possibility that
161 * the tkr's clocksource may change between the read reference, and the
162 * clock reference passed to the read function. This can cause crashes if
163 * the wrong clocksource is passed to the wrong read function.
164 * This isn't necessary to use when holding the timekeeper_lock or doing
165 * a read of the fast-timekeeper tkrs (which is protected by its own locking
168 static inline u64 tk_clock_read(const struct tk_read_base *tkr)
170 struct clocksource *clock = READ_ONCE(tkr->clock);
172 return clock->read(clock);
175 #ifdef CONFIG_DEBUG_TIMEKEEPING
176 #define WARNING_FREQ (HZ*300) /* 5 minute rate-limiting */
178 static void timekeeping_check_update(struct timekeeper *tk, u64 offset)
181 u64 max_cycles = tk->tkr_mono.clock->max_cycles;
182 const char *name = tk->tkr_mono.clock->name;
184 if (offset > max_cycles) {
185 printk_deferred("WARNING: timekeeping: Cycle offset (%lld) is larger than allowed by the '%s' clock's max_cycles value (%lld): time overflow danger\n",
186 offset, name, max_cycles);
187 printk_deferred(" timekeeping: Your kernel is sick, but tries to cope by capping time updates\n");
189 if (offset > (max_cycles >> 1)) {
190 printk_deferred("INFO: timekeeping: Cycle offset (%lld) is larger than the '%s' clock's 50%% safety margin (%lld)\n",
191 offset, name, max_cycles >> 1);
192 printk_deferred(" timekeeping: Your kernel is still fine, but is feeling a bit nervous\n");
196 if (tk->underflow_seen) {
197 if (jiffies - tk->last_warning > WARNING_FREQ) {
198 printk_deferred("WARNING: Underflow in clocksource '%s' observed, time update ignored.\n", name);
199 printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
200 printk_deferred(" Your kernel is probably still fine.\n");
201 tk->last_warning = jiffies;
203 tk->underflow_seen = 0;
206 if (tk->overflow_seen) {
207 if (jiffies - tk->last_warning > WARNING_FREQ) {
208 printk_deferred("WARNING: Overflow in clocksource '%s' observed, time update capped.\n", name);
209 printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
210 printk_deferred(" Your kernel is probably still fine.\n");
211 tk->last_warning = jiffies;
213 tk->overflow_seen = 0;
217 static inline u64 timekeeping_get_delta(const struct tk_read_base *tkr)
219 struct timekeeper *tk = &tk_core.timekeeper;
220 u64 now, last, mask, max, delta;
224 * Since we're called holding a seqlock, the data may shift
225 * under us while we're doing the calculation. This can cause
226 * false positives, since we'd note a problem but throw the
227 * results away. So nest another seqlock here to atomically
228 * grab the points we are checking with.
231 seq = read_seqcount_begin(&tk_core.seq);
232 now = tk_clock_read(tkr);
233 last = tkr->cycle_last;
235 max = tkr->clock->max_cycles;
236 } while (read_seqcount_retry(&tk_core.seq, seq));
238 delta = clocksource_delta(now, last, mask);
241 * Try to catch underflows by checking if we are seeing small
242 * mask-relative negative values.
244 if (unlikely((~delta & mask) < (mask >> 3))) {
245 tk->underflow_seen = 1;
249 /* Cap delta value to the max_cycles values to avoid mult overflows */
250 if (unlikely(delta > max)) {
251 tk->overflow_seen = 1;
252 delta = tkr->clock->max_cycles;
258 static inline void timekeeping_check_update(struct timekeeper *tk, u64 offset)
261 static inline u64 timekeeping_get_delta(const struct tk_read_base *tkr)
263 u64 cycle_now, delta;
265 /* read clocksource */
266 cycle_now = tk_clock_read(tkr);
268 /* calculate the delta since the last update_wall_time */
269 delta = clocksource_delta(cycle_now, tkr->cycle_last, tkr->mask);
276 * tk_setup_internals - Set up internals to use clocksource clock.
278 * @tk: The target timekeeper to setup.
279 * @clock: Pointer to clocksource.
281 * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
282 * pair and interval request.
284 * Unless you're the timekeeping code, you should not be using this!
286 static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock)
289 u64 tmp, ntpinterval;
290 struct clocksource *old_clock;
292 ++tk->cs_was_changed_seq;
293 old_clock = tk->tkr_mono.clock;
294 tk->tkr_mono.clock = clock;
295 tk->tkr_mono.mask = clock->mask;
296 tk->tkr_mono.cycle_last = tk_clock_read(&tk->tkr_mono);
298 tk->tkr_raw.clock = clock;
299 tk->tkr_raw.mask = clock->mask;
300 tk->tkr_raw.cycle_last = tk->tkr_mono.cycle_last;
302 /* Do the ns -> cycle conversion first, using original mult */
303 tmp = NTP_INTERVAL_LENGTH;
304 tmp <<= clock->shift;
306 tmp += clock->mult/2;
307 do_div(tmp, clock->mult);
311 interval = (u64) tmp;
312 tk->cycle_interval = interval;
314 /* Go back from cycles -> shifted ns */
315 tk->xtime_interval = interval * clock->mult;
316 tk->xtime_remainder = ntpinterval - tk->xtime_interval;
317 tk->raw_interval = interval * clock->mult;
319 /* if changing clocks, convert xtime_nsec shift units */
321 int shift_change = clock->shift - old_clock->shift;
322 if (shift_change < 0) {
323 tk->tkr_mono.xtime_nsec >>= -shift_change;
324 tk->tkr_raw.xtime_nsec >>= -shift_change;
326 tk->tkr_mono.xtime_nsec <<= shift_change;
327 tk->tkr_raw.xtime_nsec <<= shift_change;
331 tk->tkr_mono.shift = clock->shift;
332 tk->tkr_raw.shift = clock->shift;
335 tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
336 tk->ntp_tick = ntpinterval << tk->ntp_error_shift;
339 * The timekeeper keeps its own mult values for the currently
340 * active clocksource. These value will be adjusted via NTP
341 * to counteract clock drifting.
343 tk->tkr_mono.mult = clock->mult;
344 tk->tkr_raw.mult = clock->mult;
345 tk->ntp_err_mult = 0;
346 tk->skip_second_overflow = 0;
349 /* Timekeeper helper functions. */
351 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
352 static u32 default_arch_gettimeoffset(void) { return 0; }
353 u32 (*arch_gettimeoffset)(void) = default_arch_gettimeoffset;
355 static inline u32 arch_gettimeoffset(void) { return 0; }
358 static inline u64 timekeeping_delta_to_ns(const struct tk_read_base *tkr, u64 delta)
362 nsec = delta * tkr->mult + tkr->xtime_nsec;
365 /* If arch requires, add in get_arch_timeoffset() */
366 return nsec + arch_gettimeoffset();
369 static inline u64 timekeeping_get_ns(const struct tk_read_base *tkr)
373 delta = timekeeping_get_delta(tkr);
374 return timekeeping_delta_to_ns(tkr, delta);
377 static inline u64 timekeeping_cycles_to_ns(const struct tk_read_base *tkr, u64 cycles)
381 /* calculate the delta since the last update_wall_time */
382 delta = clocksource_delta(cycles, tkr->cycle_last, tkr->mask);
383 return timekeeping_delta_to_ns(tkr, delta);
387 * update_fast_timekeeper - Update the fast and NMI safe monotonic timekeeper.
388 * @tkr: Timekeeping readout base from which we take the update
390 * We want to use this from any context including NMI and tracing /
391 * instrumenting the timekeeping code itself.
393 * Employ the latch technique; see @raw_write_seqcount_latch.
395 * So if a NMI hits the update of base[0] then it will use base[1]
396 * which is still consistent. In the worst case this can result is a
397 * slightly wrong timestamp (a few nanoseconds). See
398 * @ktime_get_mono_fast_ns.
400 static void update_fast_timekeeper(const struct tk_read_base *tkr,
403 struct tk_read_base *base = tkf->base;
405 /* Force readers off to base[1] */
406 raw_write_seqcount_latch(&tkf->seq);
409 memcpy(base, tkr, sizeof(*base));
411 /* Force readers back to base[0] */
412 raw_write_seqcount_latch(&tkf->seq);
415 memcpy(base + 1, base, sizeof(*base));
419 * ktime_get_mono_fast_ns - Fast NMI safe access to clock monotonic
421 * This timestamp is not guaranteed to be monotonic across an update.
422 * The timestamp is calculated by:
424 * now = base_mono + clock_delta * slope
426 * So if the update lowers the slope, readers who are forced to the
427 * not yet updated second array are still using the old steeper slope.
436 * |12345678---> reader order
442 * So reader 6 will observe time going backwards versus reader 5.
444 * While other CPUs are likely to be able observe that, the only way
445 * for a CPU local observation is when an NMI hits in the middle of
446 * the update. Timestamps taken from that NMI context might be ahead
447 * of the following timestamps. Callers need to be aware of that and
450 static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf)
452 struct tk_read_base *tkr;
457 seq = raw_read_seqcount_latch(&tkf->seq);
458 tkr = tkf->base + (seq & 0x01);
459 now = ktime_to_ns(tkr->base);
461 now += timekeeping_delta_to_ns(tkr,
466 } while (read_seqcount_retry(&tkf->seq, seq));
471 u64 ktime_get_mono_fast_ns(void)
473 return __ktime_get_fast_ns(&tk_fast_mono);
475 EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns);
477 u64 ktime_get_raw_fast_ns(void)
479 return __ktime_get_fast_ns(&tk_fast_raw);
481 EXPORT_SYMBOL_GPL(ktime_get_raw_fast_ns);
484 * ktime_get_boot_fast_ns - NMI safe and fast access to boot clock.
486 * To keep it NMI safe since we're accessing from tracing, we're not using a
487 * separate timekeeper with updates to monotonic clock and boot offset
488 * protected with seqlocks. This has the following minor side effects:
490 * (1) Its possible that a timestamp be taken after the boot offset is updated
491 * but before the timekeeper is updated. If this happens, the new boot offset
492 * is added to the old timekeeping making the clock appear to update slightly
495 * timekeeping_inject_sleeptime64()
496 * __timekeeping_inject_sleeptime(tk, delta);
498 * timekeeping_update(tk, TK_CLEAR_NTP...);
500 * (2) On 32-bit systems, the 64-bit boot offset (tk->offs_boot) may be
501 * partially updated. Since the tk->offs_boot update is a rare event, this
502 * should be a rare occurrence which postprocessing should be able to handle.
504 u64 notrace ktime_get_boot_fast_ns(void)
506 struct timekeeper *tk = &tk_core.timekeeper;
508 return (ktime_get_mono_fast_ns() + ktime_to_ns(tk->offs_boot));
510 EXPORT_SYMBOL_GPL(ktime_get_boot_fast_ns);
514 * See comment for __ktime_get_fast_ns() vs. timestamp ordering
516 static __always_inline u64 __ktime_get_real_fast_ns(struct tk_fast *tkf)
518 struct tk_read_base *tkr;
523 seq = raw_read_seqcount_latch(&tkf->seq);
524 tkr = tkf->base + (seq & 0x01);
525 now = ktime_to_ns(tkr->base_real);
527 now += timekeeping_delta_to_ns(tkr,
532 } while (read_seqcount_retry(&tkf->seq, seq));
538 * ktime_get_real_fast_ns: - NMI safe and fast access to clock realtime.
540 u64 ktime_get_real_fast_ns(void)
542 return __ktime_get_real_fast_ns(&tk_fast_mono);
544 EXPORT_SYMBOL_GPL(ktime_get_real_fast_ns);
547 * halt_fast_timekeeper - Prevent fast timekeeper from accessing clocksource.
548 * @tk: Timekeeper to snapshot.
550 * It generally is unsafe to access the clocksource after timekeeping has been
551 * suspended, so take a snapshot of the readout base of @tk and use it as the
552 * fast timekeeper's readout base while suspended. It will return the same
553 * number of cycles every time until timekeeping is resumed at which time the
554 * proper readout base for the fast timekeeper will be restored automatically.
556 static void halt_fast_timekeeper(const struct timekeeper *tk)
558 static struct tk_read_base tkr_dummy;
559 const struct tk_read_base *tkr = &tk->tkr_mono;
561 memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
562 cycles_at_suspend = tk_clock_read(tkr);
563 tkr_dummy.clock = &dummy_clock;
564 tkr_dummy.base_real = tkr->base + tk->offs_real;
565 update_fast_timekeeper(&tkr_dummy, &tk_fast_mono);
568 memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
569 tkr_dummy.clock = &dummy_clock;
570 update_fast_timekeeper(&tkr_dummy, &tk_fast_raw);
573 static RAW_NOTIFIER_HEAD(pvclock_gtod_chain);
575 static void update_pvclock_gtod(struct timekeeper *tk, bool was_set)
577 raw_notifier_call_chain(&pvclock_gtod_chain, was_set, tk);
581 * pvclock_gtod_register_notifier - register a pvclock timedata update listener
583 int pvclock_gtod_register_notifier(struct notifier_block *nb)
585 struct timekeeper *tk = &tk_core.timekeeper;
589 raw_spin_lock_irqsave(&timekeeper_lock, flags);
590 ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb);
591 update_pvclock_gtod(tk, true);
592 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
596 EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier);
599 * pvclock_gtod_unregister_notifier - unregister a pvclock
600 * timedata update listener
602 int pvclock_gtod_unregister_notifier(struct notifier_block *nb)
607 raw_spin_lock_irqsave(&timekeeper_lock, flags);
608 ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb);
609 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
613 EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier);
616 * tk_update_leap_state - helper to update the next_leap_ktime
618 static inline void tk_update_leap_state(struct timekeeper *tk)
620 tk->next_leap_ktime = ntp_get_next_leap();
621 if (tk->next_leap_ktime != KTIME_MAX)
622 /* Convert to monotonic time */
623 tk->next_leap_ktime = ktime_sub(tk->next_leap_ktime, tk->offs_real);
627 * Update the ktime_t based scalar nsec members of the timekeeper
629 static inline void tk_update_ktime_data(struct timekeeper *tk)
635 * The xtime based monotonic readout is:
636 * nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();
637 * The ktime based monotonic readout is:
638 * nsec = base_mono + now();
639 * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec
641 seconds = (u64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec);
642 nsec = (u32) tk->wall_to_monotonic.tv_nsec;
643 tk->tkr_mono.base = ns_to_ktime(seconds * NSEC_PER_SEC + nsec);
646 * The sum of the nanoseconds portions of xtime and
647 * wall_to_monotonic can be greater/equal one second. Take
648 * this into account before updating tk->ktime_sec.
650 nsec += (u32)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
651 if (nsec >= NSEC_PER_SEC)
653 tk->ktime_sec = seconds;
655 /* Update the monotonic raw base */
656 tk->tkr_raw.base = ns_to_ktime(tk->raw_sec * NSEC_PER_SEC);
659 /* must hold timekeeper_lock */
660 static void timekeeping_update(struct timekeeper *tk, unsigned int action)
662 if (action & TK_CLEAR_NTP) {
667 tk_update_leap_state(tk);
668 tk_update_ktime_data(tk);
671 update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);
673 tk->tkr_mono.base_real = tk->tkr_mono.base + tk->offs_real;
674 update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
675 update_fast_timekeeper(&tk->tkr_raw, &tk_fast_raw);
677 if (action & TK_CLOCK_WAS_SET)
678 tk->clock_was_set_seq++;
680 * The mirroring of the data to the shadow-timekeeper needs
681 * to happen last here to ensure we don't over-write the
682 * timekeeper structure on the next update with stale data
684 if (action & TK_MIRROR)
685 memcpy(&shadow_timekeeper, &tk_core.timekeeper,
686 sizeof(tk_core.timekeeper));
690 * timekeeping_forward_now - update clock to the current time
692 * Forward the current clock to update its state since the last call to
693 * update_wall_time(). This is useful before significant clock changes,
694 * as it avoids having to deal with this time offset explicitly.
696 static void timekeeping_forward_now(struct timekeeper *tk)
698 u64 cycle_now, delta;
700 cycle_now = tk_clock_read(&tk->tkr_mono);
701 delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
702 tk->tkr_mono.cycle_last = cycle_now;
703 tk->tkr_raw.cycle_last = cycle_now;
705 tk->tkr_mono.xtime_nsec += delta * tk->tkr_mono.mult;
707 /* If arch requires, add in get_arch_timeoffset() */
708 tk->tkr_mono.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr_mono.shift;
711 tk->tkr_raw.xtime_nsec += delta * tk->tkr_raw.mult;
713 /* If arch requires, add in get_arch_timeoffset() */
714 tk->tkr_raw.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr_raw.shift;
716 tk_normalize_xtime(tk);
720 * ktime_get_real_ts64 - Returns the time of day in a timespec64.
721 * @ts: pointer to the timespec to be set
723 * Returns the time of day in a timespec64 (WARN if suspended).
725 void ktime_get_real_ts64(struct timespec64 *ts)
727 struct timekeeper *tk = &tk_core.timekeeper;
731 WARN_ON(timekeeping_suspended);
734 seq = read_seqcount_begin(&tk_core.seq);
736 ts->tv_sec = tk->xtime_sec;
737 nsecs = timekeeping_get_ns(&tk->tkr_mono);
739 } while (read_seqcount_retry(&tk_core.seq, seq));
742 timespec64_add_ns(ts, nsecs);
744 EXPORT_SYMBOL(ktime_get_real_ts64);
746 ktime_t ktime_get(void)
748 struct timekeeper *tk = &tk_core.timekeeper;
753 WARN_ON(timekeeping_suspended);
756 seq = read_seqcount_begin(&tk_core.seq);
757 base = tk->tkr_mono.base;
758 nsecs = timekeeping_get_ns(&tk->tkr_mono);
760 } while (read_seqcount_retry(&tk_core.seq, seq));
762 return ktime_add_ns(base, nsecs);
764 EXPORT_SYMBOL_GPL(ktime_get);
766 u32 ktime_get_resolution_ns(void)
768 struct timekeeper *tk = &tk_core.timekeeper;
772 WARN_ON(timekeeping_suspended);
775 seq = read_seqcount_begin(&tk_core.seq);
776 nsecs = tk->tkr_mono.mult >> tk->tkr_mono.shift;
777 } while (read_seqcount_retry(&tk_core.seq, seq));
781 EXPORT_SYMBOL_GPL(ktime_get_resolution_ns);
783 static ktime_t *offsets[TK_OFFS_MAX] = {
784 [TK_OFFS_REAL] = &tk_core.timekeeper.offs_real,
785 [TK_OFFS_BOOT] = &tk_core.timekeeper.offs_boot,
786 [TK_OFFS_TAI] = &tk_core.timekeeper.offs_tai,
789 ktime_t ktime_get_with_offset(enum tk_offsets offs)
791 struct timekeeper *tk = &tk_core.timekeeper;
793 ktime_t base, *offset = offsets[offs];
796 WARN_ON(timekeeping_suspended);
799 seq = read_seqcount_begin(&tk_core.seq);
800 base = ktime_add(tk->tkr_mono.base, *offset);
801 nsecs = timekeeping_get_ns(&tk->tkr_mono);
803 } while (read_seqcount_retry(&tk_core.seq, seq));
805 return ktime_add_ns(base, nsecs);
808 EXPORT_SYMBOL_GPL(ktime_get_with_offset);
810 ktime_t ktime_get_coarse_with_offset(enum tk_offsets offs)
812 struct timekeeper *tk = &tk_core.timekeeper;
814 ktime_t base, *offset = offsets[offs];
817 WARN_ON(timekeeping_suspended);
820 seq = read_seqcount_begin(&tk_core.seq);
821 base = ktime_add(tk->tkr_mono.base, *offset);
822 nsecs = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
824 } while (read_seqcount_retry(&tk_core.seq, seq));
826 return ktime_add_ns(base, nsecs);
828 EXPORT_SYMBOL_GPL(ktime_get_coarse_with_offset);
831 * ktime_mono_to_any() - convert mononotic time to any other time
832 * @tmono: time to convert.
833 * @offs: which offset to use
835 ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs)
837 ktime_t *offset = offsets[offs];
842 seq = read_seqcount_begin(&tk_core.seq);
843 tconv = ktime_add(tmono, *offset);
844 } while (read_seqcount_retry(&tk_core.seq, seq));
848 EXPORT_SYMBOL_GPL(ktime_mono_to_any);
851 * ktime_get_raw - Returns the raw monotonic time in ktime_t format
853 ktime_t ktime_get_raw(void)
855 struct timekeeper *tk = &tk_core.timekeeper;
861 seq = read_seqcount_begin(&tk_core.seq);
862 base = tk->tkr_raw.base;
863 nsecs = timekeeping_get_ns(&tk->tkr_raw);
865 } while (read_seqcount_retry(&tk_core.seq, seq));
867 return ktime_add_ns(base, nsecs);
869 EXPORT_SYMBOL_GPL(ktime_get_raw);
872 * ktime_get_ts64 - get the monotonic clock in timespec64 format
873 * @ts: pointer to timespec variable
875 * The function calculates the monotonic clock from the realtime
876 * clock and the wall_to_monotonic offset and stores the result
877 * in normalized timespec64 format in the variable pointed to by @ts.
879 void ktime_get_ts64(struct timespec64 *ts)
881 struct timekeeper *tk = &tk_core.timekeeper;
882 struct timespec64 tomono;
886 WARN_ON(timekeeping_suspended);
889 seq = read_seqcount_begin(&tk_core.seq);
890 ts->tv_sec = tk->xtime_sec;
891 nsec = timekeeping_get_ns(&tk->tkr_mono);
892 tomono = tk->wall_to_monotonic;
894 } while (read_seqcount_retry(&tk_core.seq, seq));
896 ts->tv_sec += tomono.tv_sec;
898 timespec64_add_ns(ts, nsec + tomono.tv_nsec);
900 EXPORT_SYMBOL_GPL(ktime_get_ts64);
903 * ktime_get_seconds - Get the seconds portion of CLOCK_MONOTONIC
905 * Returns the seconds portion of CLOCK_MONOTONIC with a single non
906 * serialized read. tk->ktime_sec is of type 'unsigned long' so this
907 * works on both 32 and 64 bit systems. On 32 bit systems the readout
908 * covers ~136 years of uptime which should be enough to prevent
909 * premature wrap arounds.
911 time64_t ktime_get_seconds(void)
913 struct timekeeper *tk = &tk_core.timekeeper;
915 WARN_ON(timekeeping_suspended);
916 return tk->ktime_sec;
918 EXPORT_SYMBOL_GPL(ktime_get_seconds);
921 * ktime_get_real_seconds - Get the seconds portion of CLOCK_REALTIME
923 * Returns the wall clock seconds since 1970. This replaces the
924 * get_seconds() interface which is not y2038 safe on 32bit systems.
926 * For 64bit systems the fast access to tk->xtime_sec is preserved. On
927 * 32bit systems the access must be protected with the sequence
928 * counter to provide "atomic" access to the 64bit tk->xtime_sec
931 time64_t ktime_get_real_seconds(void)
933 struct timekeeper *tk = &tk_core.timekeeper;
937 if (IS_ENABLED(CONFIG_64BIT))
938 return tk->xtime_sec;
941 seq = read_seqcount_begin(&tk_core.seq);
942 seconds = tk->xtime_sec;
944 } while (read_seqcount_retry(&tk_core.seq, seq));
948 EXPORT_SYMBOL_GPL(ktime_get_real_seconds);
951 * __ktime_get_real_seconds - The same as ktime_get_real_seconds
952 * but without the sequence counter protect. This internal function
953 * is called just when timekeeping lock is already held.
955 time64_t __ktime_get_real_seconds(void)
957 struct timekeeper *tk = &tk_core.timekeeper;
959 return tk->xtime_sec;
963 * ktime_get_snapshot - snapshots the realtime/monotonic raw clocks with counter
964 * @systime_snapshot: pointer to struct receiving the system time snapshot
966 void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot)
968 struct timekeeper *tk = &tk_core.timekeeper;
976 WARN_ON_ONCE(timekeeping_suspended);
979 seq = read_seqcount_begin(&tk_core.seq);
980 now = tk_clock_read(&tk->tkr_mono);
981 systime_snapshot->cs_was_changed_seq = tk->cs_was_changed_seq;
982 systime_snapshot->clock_was_set_seq = tk->clock_was_set_seq;
983 base_real = ktime_add(tk->tkr_mono.base,
984 tk_core.timekeeper.offs_real);
985 base_raw = tk->tkr_raw.base;
986 nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, now);
987 nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw, now);
988 } while (read_seqcount_retry(&tk_core.seq, seq));
990 systime_snapshot->cycles = now;
991 systime_snapshot->real = ktime_add_ns(base_real, nsec_real);
992 systime_snapshot->raw = ktime_add_ns(base_raw, nsec_raw);
994 EXPORT_SYMBOL_GPL(ktime_get_snapshot);
996 /* Scale base by mult/div checking for overflow */
997 static int scale64_check_overflow(u64 mult, u64 div, u64 *base)
1001 tmp = div64_u64_rem(*base, div, &rem);
1003 if (((int)sizeof(u64)*8 - fls64(mult) < fls64(tmp)) ||
1004 ((int)sizeof(u64)*8 - fls64(mult) < fls64(rem)))
1008 rem = div64_u64(rem * mult, div);
1014 * adjust_historical_crosststamp - adjust crosstimestamp previous to current interval
1015 * @history: Snapshot representing start of history
1016 * @partial_history_cycles: Cycle offset into history (fractional part)
1017 * @total_history_cycles: Total history length in cycles
1018 * @discontinuity: True indicates clock was set on history period
1019 * @ts: Cross timestamp that should be adjusted using
1020 * partial/total ratio
1022 * Helper function used by get_device_system_crosststamp() to correct the
1023 * crosstimestamp corresponding to the start of the current interval to the
1024 * system counter value (timestamp point) provided by the driver. The
1025 * total_history_* quantities are the total history starting at the provided
1026 * reference point and ending at the start of the current interval. The cycle
1027 * count between the driver timestamp point and the start of the current
1028 * interval is partial_history_cycles.
1030 static int adjust_historical_crosststamp(struct system_time_snapshot *history,
1031 u64 partial_history_cycles,
1032 u64 total_history_cycles,
1034 struct system_device_crosststamp *ts)
1036 struct timekeeper *tk = &tk_core.timekeeper;
1037 u64 corr_raw, corr_real;
1038 bool interp_forward;
1041 if (total_history_cycles == 0 || partial_history_cycles == 0)
1044 /* Interpolate shortest distance from beginning or end of history */
1045 interp_forward = partial_history_cycles > total_history_cycles / 2;
1046 partial_history_cycles = interp_forward ?
1047 total_history_cycles - partial_history_cycles :
1048 partial_history_cycles;
1051 * Scale the monotonic raw time delta by:
1052 * partial_history_cycles / total_history_cycles
1054 corr_raw = (u64)ktime_to_ns(
1055 ktime_sub(ts->sys_monoraw, history->raw));
1056 ret = scale64_check_overflow(partial_history_cycles,
1057 total_history_cycles, &corr_raw);
1062 * If there is a discontinuity in the history, scale monotonic raw
1064 * mult(real)/mult(raw) yielding the realtime correction
1065 * Otherwise, calculate the realtime correction similar to monotonic
1068 if (discontinuity) {
1069 corr_real = mul_u64_u32_div
1070 (corr_raw, tk->tkr_mono.mult, tk->tkr_raw.mult);
1072 corr_real = (u64)ktime_to_ns(
1073 ktime_sub(ts->sys_realtime, history->real));
1074 ret = scale64_check_overflow(partial_history_cycles,
1075 total_history_cycles, &corr_real);
1080 /* Fixup monotonic raw and real time time values */
1081 if (interp_forward) {
1082 ts->sys_monoraw = ktime_add_ns(history->raw, corr_raw);
1083 ts->sys_realtime = ktime_add_ns(history->real, corr_real);
1085 ts->sys_monoraw = ktime_sub_ns(ts->sys_monoraw, corr_raw);
1086 ts->sys_realtime = ktime_sub_ns(ts->sys_realtime, corr_real);
1093 * cycle_between - true if test occurs chronologically between before and after
1095 static bool cycle_between(u64 before, u64 test, u64 after)
1097 if (test > before && test < after)
1099 if (test < before && before > after)
1105 * get_device_system_crosststamp - Synchronously capture system/device timestamp
1106 * @get_time_fn: Callback to get simultaneous device time and
1107 * system counter from the device driver
1108 * @ctx: Context passed to get_time_fn()
1109 * @history_begin: Historical reference point used to interpolate system
1110 * time when counter provided by the driver is before the current interval
1111 * @xtstamp: Receives simultaneously captured system and device time
1113 * Reads a timestamp from a device and correlates it to system time
1115 int get_device_system_crosststamp(int (*get_time_fn)
1116 (ktime_t *device_time,
1117 struct system_counterval_t *sys_counterval,
1120 struct system_time_snapshot *history_begin,
1121 struct system_device_crosststamp *xtstamp)
1123 struct system_counterval_t system_counterval;
1124 struct timekeeper *tk = &tk_core.timekeeper;
1125 u64 cycles, now, interval_start;
1126 unsigned int clock_was_set_seq = 0;
1127 ktime_t base_real, base_raw;
1128 u64 nsec_real, nsec_raw;
1129 u8 cs_was_changed_seq;
1135 seq = read_seqcount_begin(&tk_core.seq);
1137 * Try to synchronously capture device time and a system
1138 * counter value calling back into the device driver
1140 ret = get_time_fn(&xtstamp->device, &system_counterval, ctx);
1145 * Verify that the clocksource associated with the captured
1146 * system counter value is the same as the currently installed
1147 * timekeeper clocksource
1149 if (tk->tkr_mono.clock != system_counterval.cs)
1151 cycles = system_counterval.cycles;
1154 * Check whether the system counter value provided by the
1155 * device driver is on the current timekeeping interval.
1157 now = tk_clock_read(&tk->tkr_mono);
1158 interval_start = tk->tkr_mono.cycle_last;
1159 if (!cycle_between(interval_start, cycles, now)) {
1160 clock_was_set_seq = tk->clock_was_set_seq;
1161 cs_was_changed_seq = tk->cs_was_changed_seq;
1162 cycles = interval_start;
1168 base_real = ktime_add(tk->tkr_mono.base,
1169 tk_core.timekeeper.offs_real);
1170 base_raw = tk->tkr_raw.base;
1172 nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono,
1173 system_counterval.cycles);
1174 nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw,
1175 system_counterval.cycles);
1176 } while (read_seqcount_retry(&tk_core.seq, seq));
1178 xtstamp->sys_realtime = ktime_add_ns(base_real, nsec_real);
1179 xtstamp->sys_monoraw = ktime_add_ns(base_raw, nsec_raw);
1182 * Interpolate if necessary, adjusting back from the start of the
1186 u64 partial_history_cycles, total_history_cycles;
1190 * Check that the counter value occurs after the provided
1191 * history reference and that the history doesn't cross a
1192 * clocksource change
1194 if (!history_begin ||
1195 !cycle_between(history_begin->cycles,
1196 system_counterval.cycles, cycles) ||
1197 history_begin->cs_was_changed_seq != cs_was_changed_seq)
1199 partial_history_cycles = cycles - system_counterval.cycles;
1200 total_history_cycles = cycles - history_begin->cycles;
1202 history_begin->clock_was_set_seq != clock_was_set_seq;
1204 ret = adjust_historical_crosststamp(history_begin,
1205 partial_history_cycles,
1206 total_history_cycles,
1207 discontinuity, xtstamp);
1214 EXPORT_SYMBOL_GPL(get_device_system_crosststamp);
1217 * do_settimeofday64 - Sets the time of day.
1218 * @ts: pointer to the timespec64 variable containing the new time
1220 * Sets the time of day to the new time and update NTP and notify hrtimers
1222 int do_settimeofday64(const struct timespec64 *ts)
1224 struct timekeeper *tk = &tk_core.timekeeper;
1225 struct timespec64 ts_delta, xt;
1226 unsigned long flags;
1229 if (!timespec64_valid_settod(ts))
1232 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1233 write_seqcount_begin(&tk_core.seq);
1235 timekeeping_forward_now(tk);
1238 ts_delta.tv_sec = ts->tv_sec - xt.tv_sec;
1239 ts_delta.tv_nsec = ts->tv_nsec - xt.tv_nsec;
1241 if (timespec64_compare(&tk->wall_to_monotonic, &ts_delta) > 0) {
1246 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));
1248 tk_set_xtime(tk, ts);
1250 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1252 write_seqcount_end(&tk_core.seq);
1253 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1255 /* signal hrtimers about time change */
1260 EXPORT_SYMBOL(do_settimeofday64);
1263 * timekeeping_inject_offset - Adds or subtracts from the current time.
1264 * @tv: pointer to the timespec variable containing the offset
1266 * Adds or subtracts an offset value from the current time.
1268 static int timekeeping_inject_offset(const struct timespec64 *ts)
1270 struct timekeeper *tk = &tk_core.timekeeper;
1271 unsigned long flags;
1272 struct timespec64 tmp;
1275 if (ts->tv_nsec < 0 || ts->tv_nsec >= NSEC_PER_SEC)
1278 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1279 write_seqcount_begin(&tk_core.seq);
1281 timekeeping_forward_now(tk);
1283 /* Make sure the proposed value is valid */
1284 tmp = timespec64_add(tk_xtime(tk), *ts);
1285 if (timespec64_compare(&tk->wall_to_monotonic, ts) > 0 ||
1286 !timespec64_valid_settod(&tmp)) {
1291 tk_xtime_add(tk, ts);
1292 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *ts));
1294 error: /* even if we error out, we forwarded the time, so call update */
1295 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1297 write_seqcount_end(&tk_core.seq);
1298 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1300 /* signal hrtimers about time change */
1307 * Indicates if there is an offset between the system clock and the hardware
1308 * clock/persistent clock/rtc.
1310 int persistent_clock_is_local;
1313 * Adjust the time obtained from the CMOS to be UTC time instead of
1316 * This is ugly, but preferable to the alternatives. Otherwise we
1317 * would either need to write a program to do it in /etc/rc (and risk
1318 * confusion if the program gets run more than once; it would also be
1319 * hard to make the program warp the clock precisely n hours) or
1320 * compile in the timezone information into the kernel. Bad, bad....
1324 * The best thing to do is to keep the CMOS clock in universal time (UTC)
1325 * as real UNIX machines always do it. This avoids all headaches about
1326 * daylight saving times and warping kernel clocks.
1328 void timekeeping_warp_clock(void)
1330 if (sys_tz.tz_minuteswest != 0) {
1331 struct timespec64 adjust;
1333 persistent_clock_is_local = 1;
1334 adjust.tv_sec = sys_tz.tz_minuteswest * 60;
1336 timekeeping_inject_offset(&adjust);
1341 * __timekeeping_set_tai_offset - Sets the TAI offset from UTC and monotonic
1344 static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset)
1346 tk->tai_offset = tai_offset;
1347 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tai_offset, 0));
1351 * change_clocksource - Swaps clocksources if a new one is available
1353 * Accumulates current time interval and initializes new clocksource
1355 static int change_clocksource(void *data)
1357 struct timekeeper *tk = &tk_core.timekeeper;
1358 struct clocksource *new, *old;
1359 unsigned long flags;
1361 new = (struct clocksource *) data;
1363 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1364 write_seqcount_begin(&tk_core.seq);
1366 timekeeping_forward_now(tk);
1368 * If the cs is in module, get a module reference. Succeeds
1369 * for built-in code (owner == NULL) as well.
1371 if (try_module_get(new->owner)) {
1372 if (!new->enable || new->enable(new) == 0) {
1373 old = tk->tkr_mono.clock;
1374 tk_setup_internals(tk, new);
1377 module_put(old->owner);
1379 module_put(new->owner);
1382 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1384 write_seqcount_end(&tk_core.seq);
1385 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1391 * timekeeping_notify - Install a new clock source
1392 * @clock: pointer to the clock source
1394 * This function is called from clocksource.c after a new, better clock
1395 * source has been registered. The caller holds the clocksource_mutex.
1397 int timekeeping_notify(struct clocksource *clock)
1399 struct timekeeper *tk = &tk_core.timekeeper;
1401 if (tk->tkr_mono.clock == clock)
1403 stop_machine(change_clocksource, clock, NULL);
1404 tick_clock_notify();
1405 return tk->tkr_mono.clock == clock ? 0 : -1;
1409 * ktime_get_raw_ts64 - Returns the raw monotonic time in a timespec
1410 * @ts: pointer to the timespec64 to be set
1412 * Returns the raw monotonic time (completely un-modified by ntp)
1414 void ktime_get_raw_ts64(struct timespec64 *ts)
1416 struct timekeeper *tk = &tk_core.timekeeper;
1421 seq = read_seqcount_begin(&tk_core.seq);
1422 ts->tv_sec = tk->raw_sec;
1423 nsecs = timekeeping_get_ns(&tk->tkr_raw);
1425 } while (read_seqcount_retry(&tk_core.seq, seq));
1428 timespec64_add_ns(ts, nsecs);
1430 EXPORT_SYMBOL(ktime_get_raw_ts64);
1434 * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
1436 int timekeeping_valid_for_hres(void)
1438 struct timekeeper *tk = &tk_core.timekeeper;
1443 seq = read_seqcount_begin(&tk_core.seq);
1445 ret = tk->tkr_mono.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
1447 } while (read_seqcount_retry(&tk_core.seq, seq));
1453 * timekeeping_max_deferment - Returns max time the clocksource can be deferred
1455 u64 timekeeping_max_deferment(void)
1457 struct timekeeper *tk = &tk_core.timekeeper;
1462 seq = read_seqcount_begin(&tk_core.seq);
1464 ret = tk->tkr_mono.clock->max_idle_ns;
1466 } while (read_seqcount_retry(&tk_core.seq, seq));
1472 * read_persistent_clock - Return time from the persistent clock.
1474 * Weak dummy function for arches that do not yet support it.
1475 * Reads the time from the battery backed persistent clock.
1476 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
1478 * XXX - Do be sure to remove it once all arches implement it.
1480 void __weak read_persistent_clock(struct timespec *ts)
1486 void __weak read_persistent_clock64(struct timespec64 *ts64)
1490 read_persistent_clock(&ts);
1491 *ts64 = timespec_to_timespec64(ts);
1495 * read_persistent_wall_and_boot_offset - Read persistent clock, and also offset
1498 * Weak dummy function for arches that do not yet support it.
1499 * wall_time - current time as returned by persistent clock
1500 * boot_offset - offset that is defined as wall_time - boot_time
1501 * The default function calculates offset based on the current value of
1502 * local_clock(). This way architectures that support sched_clock() but don't
1503 * support dedicated boot time clock will provide the best estimate of the
1507 read_persistent_wall_and_boot_offset(struct timespec64 *wall_time,
1508 struct timespec64 *boot_offset)
1510 read_persistent_clock64(wall_time);
1511 *boot_offset = ns_to_timespec64(local_clock());
1515 * Flag reflecting whether timekeeping_resume() has injected sleeptime.
1517 * The flag starts of false and is only set when a suspend reaches
1518 * timekeeping_suspend(), timekeeping_resume() sets it to false when the
1519 * timekeeper clocksource is not stopping across suspend and has been
1520 * used to update sleep time. If the timekeeper clocksource has stopped
1521 * then the flag stays true and is used by the RTC resume code to decide
1522 * whether sleeptime must be injected and if so the flag gets false then.
1524 * If a suspend fails before reaching timekeeping_resume() then the flag
1525 * stays false and prevents erroneous sleeptime injection.
1527 static bool suspend_timing_needed;
1529 /* Flag for if there is a persistent clock on this platform */
1530 static bool persistent_clock_exists;
1533 * timekeeping_init - Initializes the clocksource and common timekeeping values
1535 void __init timekeeping_init(void)
1537 struct timespec64 wall_time, boot_offset, wall_to_mono;
1538 struct timekeeper *tk = &tk_core.timekeeper;
1539 struct clocksource *clock;
1540 unsigned long flags;
1542 read_persistent_wall_and_boot_offset(&wall_time, &boot_offset);
1543 if (timespec64_valid_settod(&wall_time) &&
1544 timespec64_to_ns(&wall_time) > 0) {
1545 persistent_clock_exists = true;
1546 } else if (timespec64_to_ns(&wall_time) != 0) {
1547 pr_warn("Persistent clock returned invalid value");
1548 wall_time = (struct timespec64){0};
1551 if (timespec64_compare(&wall_time, &boot_offset) < 0)
1552 boot_offset = (struct timespec64){0};
1555 * We want set wall_to_mono, so the following is true:
1556 * wall time + wall_to_mono = boot time
1558 wall_to_mono = timespec64_sub(boot_offset, wall_time);
1560 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1561 write_seqcount_begin(&tk_core.seq);
1564 clock = clocksource_default_clock();
1566 clock->enable(clock);
1567 tk_setup_internals(tk, clock);
1569 tk_set_xtime(tk, &wall_time);
1572 tk_set_wall_to_mono(tk, wall_to_mono);
1574 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1576 write_seqcount_end(&tk_core.seq);
1577 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1580 /* time in seconds when suspend began for persistent clock */
1581 static struct timespec64 timekeeping_suspend_time;
1584 * __timekeeping_inject_sleeptime - Internal function to add sleep interval
1585 * @delta: pointer to a timespec delta value
1587 * Takes a timespec offset measuring a suspend interval and properly
1588 * adds the sleep offset to the timekeeping variables.
1590 static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
1591 const struct timespec64 *delta)
1593 if (!timespec64_valid_strict(delta)) {
1594 printk_deferred(KERN_WARNING
1595 "__timekeeping_inject_sleeptime: Invalid "
1596 "sleep delta value!\n");
1599 tk_xtime_add(tk, delta);
1600 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *delta));
1601 tk_update_sleep_time(tk, timespec64_to_ktime(*delta));
1602 tk_debug_account_sleep_time(delta);
1605 #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
1607 * We have three kinds of time sources to use for sleep time
1608 * injection, the preference order is:
1609 * 1) non-stop clocksource
1610 * 2) persistent clock (ie: RTC accessible when irqs are off)
1613 * 1) and 2) are used by timekeeping, 3) by RTC subsystem.
1614 * If system has neither 1) nor 2), 3) will be used finally.
1617 * If timekeeping has injected sleeptime via either 1) or 2),
1618 * 3) becomes needless, so in this case we don't need to call
1619 * rtc_resume(), and this is what timekeeping_rtc_skipresume()
1622 bool timekeeping_rtc_skipresume(void)
1624 return !suspend_timing_needed;
1628 * 1) can be determined whether to use or not only when doing
1629 * timekeeping_resume() which is invoked after rtc_suspend(),
1630 * so we can't skip rtc_suspend() surely if system has 1).
1632 * But if system has 2), 2) will definitely be used, so in this
1633 * case we don't need to call rtc_suspend(), and this is what
1634 * timekeeping_rtc_skipsuspend() means.
1636 bool timekeeping_rtc_skipsuspend(void)
1638 return persistent_clock_exists;
1642 * timekeeping_inject_sleeptime64 - Adds suspend interval to timeekeeping values
1643 * @delta: pointer to a timespec64 delta value
1645 * This hook is for architectures that cannot support read_persistent_clock64
1646 * because their RTC/persistent clock is only accessible when irqs are enabled.
1647 * and also don't have an effective nonstop clocksource.
1649 * This function should only be called by rtc_resume(), and allows
1650 * a suspend offset to be injected into the timekeeping values.
1652 void timekeeping_inject_sleeptime64(const struct timespec64 *delta)
1654 struct timekeeper *tk = &tk_core.timekeeper;
1655 unsigned long flags;
1657 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1658 write_seqcount_begin(&tk_core.seq);
1660 suspend_timing_needed = false;
1662 timekeeping_forward_now(tk);
1664 __timekeeping_inject_sleeptime(tk, delta);
1666 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1668 write_seqcount_end(&tk_core.seq);
1669 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1671 /* signal hrtimers about time change */
1677 * timekeeping_resume - Resumes the generic timekeeping subsystem.
1679 void timekeeping_resume(void)
1681 struct timekeeper *tk = &tk_core.timekeeper;
1682 struct clocksource *clock = tk->tkr_mono.clock;
1683 unsigned long flags;
1684 struct timespec64 ts_new, ts_delta;
1685 u64 cycle_now, nsec;
1686 bool inject_sleeptime = false;
1688 read_persistent_clock64(&ts_new);
1690 clockevents_resume();
1691 clocksource_resume();
1693 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1694 write_seqcount_begin(&tk_core.seq);
1697 * After system resumes, we need to calculate the suspended time and
1698 * compensate it for the OS time. There are 3 sources that could be
1699 * used: Nonstop clocksource during suspend, persistent clock and rtc
1702 * One specific platform may have 1 or 2 or all of them, and the
1703 * preference will be:
1704 * suspend-nonstop clocksource -> persistent clock -> rtc
1705 * The less preferred source will only be tried if there is no better
1706 * usable source. The rtc part is handled separately in rtc core code.
1708 cycle_now = tk_clock_read(&tk->tkr_mono);
1709 nsec = clocksource_stop_suspend_timing(clock, cycle_now);
1711 ts_delta = ns_to_timespec64(nsec);
1712 inject_sleeptime = true;
1713 } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) {
1714 ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time);
1715 inject_sleeptime = true;
1718 if (inject_sleeptime) {
1719 suspend_timing_needed = false;
1720 __timekeeping_inject_sleeptime(tk, &ts_delta);
1723 /* Re-base the last cycle value */
1724 tk->tkr_mono.cycle_last = cycle_now;
1725 tk->tkr_raw.cycle_last = cycle_now;
1728 timekeeping_suspended = 0;
1729 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1730 write_seqcount_end(&tk_core.seq);
1731 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1733 touch_softlockup_watchdog();
1739 int timekeeping_suspend(void)
1741 struct timekeeper *tk = &tk_core.timekeeper;
1742 unsigned long flags;
1743 struct timespec64 delta, delta_delta;
1744 static struct timespec64 old_delta;
1745 struct clocksource *curr_clock;
1748 read_persistent_clock64(&timekeeping_suspend_time);
1751 * On some systems the persistent_clock can not be detected at
1752 * timekeeping_init by its return value, so if we see a valid
1753 * value returned, update the persistent_clock_exists flag.
1755 if (timekeeping_suspend_time.tv_sec || timekeeping_suspend_time.tv_nsec)
1756 persistent_clock_exists = true;
1758 suspend_timing_needed = true;
1760 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1761 write_seqcount_begin(&tk_core.seq);
1762 timekeeping_forward_now(tk);
1763 timekeeping_suspended = 1;
1766 * Since we've called forward_now, cycle_last stores the value
1767 * just read from the current clocksource. Save this to potentially
1768 * use in suspend timing.
1770 curr_clock = tk->tkr_mono.clock;
1771 cycle_now = tk->tkr_mono.cycle_last;
1772 clocksource_start_suspend_timing(curr_clock, cycle_now);
1774 if (persistent_clock_exists) {
1776 * To avoid drift caused by repeated suspend/resumes,
1777 * which each can add ~1 second drift error,
1778 * try to compensate so the difference in system time
1779 * and persistent_clock time stays close to constant.
1781 delta = timespec64_sub(tk_xtime(tk), timekeeping_suspend_time);
1782 delta_delta = timespec64_sub(delta, old_delta);
1783 if (abs(delta_delta.tv_sec) >= 2) {
1785 * if delta_delta is too large, assume time correction
1786 * has occurred and set old_delta to the current delta.
1790 /* Otherwise try to adjust old_system to compensate */
1791 timekeeping_suspend_time =
1792 timespec64_add(timekeeping_suspend_time, delta_delta);
1796 timekeeping_update(tk, TK_MIRROR);
1797 halt_fast_timekeeper(tk);
1798 write_seqcount_end(&tk_core.seq);
1799 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1802 clocksource_suspend();
1803 clockevents_suspend();
1808 /* sysfs resume/suspend bits for timekeeping */
1809 static struct syscore_ops timekeeping_syscore_ops = {
1810 .resume = timekeeping_resume,
1811 .suspend = timekeeping_suspend,
1814 static int __init timekeeping_init_ops(void)
1816 register_syscore_ops(&timekeeping_syscore_ops);
1819 device_initcall(timekeeping_init_ops);
1822 * Apply a multiplier adjustment to the timekeeper
1824 static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk,
1828 s64 interval = tk->cycle_interval;
1830 if (mult_adj == 0) {
1832 } else if (mult_adj == -1) {
1833 interval = -interval;
1835 } else if (mult_adj != 1) {
1836 interval *= mult_adj;
1841 * So the following can be confusing.
1843 * To keep things simple, lets assume mult_adj == 1 for now.
1845 * When mult_adj != 1, remember that the interval and offset values
1846 * have been appropriately scaled so the math is the same.
1848 * The basic idea here is that we're increasing the multiplier
1849 * by one, this causes the xtime_interval to be incremented by
1850 * one cycle_interval. This is because:
1851 * xtime_interval = cycle_interval * mult
1852 * So if mult is being incremented by one:
1853 * xtime_interval = cycle_interval * (mult + 1)
1855 * xtime_interval = (cycle_interval * mult) + cycle_interval
1856 * Which can be shortened to:
1857 * xtime_interval += cycle_interval
1859 * So offset stores the non-accumulated cycles. Thus the current
1860 * time (in shifted nanoseconds) is:
1861 * now = (offset * adj) + xtime_nsec
1862 * Now, even though we're adjusting the clock frequency, we have
1863 * to keep time consistent. In other words, we can't jump back
1864 * in time, and we also want to avoid jumping forward in time.
1866 * So given the same offset value, we need the time to be the same
1867 * both before and after the freq adjustment.
1868 * now = (offset * adj_1) + xtime_nsec_1
1869 * now = (offset * adj_2) + xtime_nsec_2
1871 * (offset * adj_1) + xtime_nsec_1 =
1872 * (offset * adj_2) + xtime_nsec_2
1876 * (offset * adj_1) + xtime_nsec_1 =
1877 * (offset * (adj_1+1)) + xtime_nsec_2
1878 * (offset * adj_1) + xtime_nsec_1 =
1879 * (offset * adj_1) + offset + xtime_nsec_2
1880 * Canceling the sides:
1881 * xtime_nsec_1 = offset + xtime_nsec_2
1883 * xtime_nsec_2 = xtime_nsec_1 - offset
1884 * Which simplfies to:
1885 * xtime_nsec -= offset
1887 if ((mult_adj > 0) && (tk->tkr_mono.mult + mult_adj < mult_adj)) {
1888 /* NTP adjustment caused clocksource mult overflow */
1893 tk->tkr_mono.mult += mult_adj;
1894 tk->xtime_interval += interval;
1895 tk->tkr_mono.xtime_nsec -= offset;
1899 * Adjust the timekeeper's multiplier to the correct frequency
1900 * and also to reduce the accumulated error value.
1902 static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
1907 * Determine the multiplier from the current NTP tick length.
1908 * Avoid expensive division when the tick length doesn't change.
1910 if (likely(tk->ntp_tick == ntp_tick_length())) {
1911 mult = tk->tkr_mono.mult - tk->ntp_err_mult;
1913 tk->ntp_tick = ntp_tick_length();
1914 mult = div64_u64((tk->ntp_tick >> tk->ntp_error_shift) -
1915 tk->xtime_remainder, tk->cycle_interval);
1919 * If the clock is behind the NTP time, increase the multiplier by 1
1920 * to catch up with it. If it's ahead and there was a remainder in the
1921 * tick division, the clock will slow down. Otherwise it will stay
1922 * ahead until the tick length changes to a non-divisible value.
1924 tk->ntp_err_mult = tk->ntp_error > 0 ? 1 : 0;
1925 mult += tk->ntp_err_mult;
1927 timekeeping_apply_adjustment(tk, offset, mult - tk->tkr_mono.mult);
1929 if (unlikely(tk->tkr_mono.clock->maxadj &&
1930 (abs(tk->tkr_mono.mult - tk->tkr_mono.clock->mult)
1931 > tk->tkr_mono.clock->maxadj))) {
1932 printk_once(KERN_WARNING
1933 "Adjusting %s more than 11%% (%ld vs %ld)\n",
1934 tk->tkr_mono.clock->name, (long)tk->tkr_mono.mult,
1935 (long)tk->tkr_mono.clock->mult + tk->tkr_mono.clock->maxadj);
1939 * It may be possible that when we entered this function, xtime_nsec
1940 * was very small. Further, if we're slightly speeding the clocksource
1941 * in the code above, its possible the required corrective factor to
1942 * xtime_nsec could cause it to underflow.
1944 * Now, since we have already accumulated the second and the NTP
1945 * subsystem has been notified via second_overflow(), we need to skip
1948 if (unlikely((s64)tk->tkr_mono.xtime_nsec < 0)) {
1949 tk->tkr_mono.xtime_nsec += (u64)NSEC_PER_SEC <<
1952 tk->skip_second_overflow = 1;
1957 * accumulate_nsecs_to_secs - Accumulates nsecs into secs
1959 * Helper function that accumulates the nsecs greater than a second
1960 * from the xtime_nsec field to the xtime_secs field.
1961 * It also calls into the NTP code to handle leapsecond processing.
1964 static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper *tk)
1966 u64 nsecps = (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
1967 unsigned int clock_set = 0;
1969 while (tk->tkr_mono.xtime_nsec >= nsecps) {
1972 tk->tkr_mono.xtime_nsec -= nsecps;
1976 * Skip NTP update if this second was accumulated before,
1977 * i.e. xtime_nsec underflowed in timekeeping_adjust()
1979 if (unlikely(tk->skip_second_overflow)) {
1980 tk->skip_second_overflow = 0;
1984 /* Figure out if its a leap sec and apply if needed */
1985 leap = second_overflow(tk->xtime_sec);
1986 if (unlikely(leap)) {
1987 struct timespec64 ts;
1989 tk->xtime_sec += leap;
1993 tk_set_wall_to_mono(tk,
1994 timespec64_sub(tk->wall_to_monotonic, ts));
1996 __timekeeping_set_tai_offset(tk, tk->tai_offset - leap);
1998 clock_set = TK_CLOCK_WAS_SET;
2005 * logarithmic_accumulation - shifted accumulation of cycles
2007 * This functions accumulates a shifted interval of cycles into
2008 * into a shifted interval nanoseconds. Allows for O(log) accumulation
2011 * Returns the unconsumed cycles.
2013 static u64 logarithmic_accumulation(struct timekeeper *tk, u64 offset,
2014 u32 shift, unsigned int *clock_set)
2016 u64 interval = tk->cycle_interval << shift;
2019 /* If the offset is smaller than a shifted interval, do nothing */
2020 if (offset < interval)
2023 /* Accumulate one shifted interval */
2025 tk->tkr_mono.cycle_last += interval;
2026 tk->tkr_raw.cycle_last += interval;
2028 tk->tkr_mono.xtime_nsec += tk->xtime_interval << shift;
2029 *clock_set |= accumulate_nsecs_to_secs(tk);
2031 /* Accumulate raw time */
2032 tk->tkr_raw.xtime_nsec += tk->raw_interval << shift;
2033 snsec_per_sec = (u64)NSEC_PER_SEC << tk->tkr_raw.shift;
2034 while (tk->tkr_raw.xtime_nsec >= snsec_per_sec) {
2035 tk->tkr_raw.xtime_nsec -= snsec_per_sec;
2039 /* Accumulate error between NTP and clock interval */
2040 tk->ntp_error += tk->ntp_tick << shift;
2041 tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) <<
2042 (tk->ntp_error_shift + shift);
2048 * timekeeping_advance - Updates the timekeeper to the current time and
2049 * current NTP tick length
2051 static void timekeeping_advance(enum timekeeping_adv_mode mode)
2053 struct timekeeper *real_tk = &tk_core.timekeeper;
2054 struct timekeeper *tk = &shadow_timekeeper;
2056 int shift = 0, maxshift;
2057 unsigned int clock_set = 0;
2058 unsigned long flags;
2060 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2062 /* Make sure we're fully resumed: */
2063 if (unlikely(timekeeping_suspended))
2066 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
2067 offset = real_tk->cycle_interval;
2069 if (mode != TK_ADV_TICK)
2072 offset = clocksource_delta(tk_clock_read(&tk->tkr_mono),
2073 tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
2075 /* Check if there's really nothing to do */
2076 if (offset < real_tk->cycle_interval && mode == TK_ADV_TICK)
2080 /* Do some additional sanity checking */
2081 timekeeping_check_update(tk, offset);
2084 * With NO_HZ we may have to accumulate many cycle_intervals
2085 * (think "ticks") worth of time at once. To do this efficiently,
2086 * we calculate the largest doubling multiple of cycle_intervals
2087 * that is smaller than the offset. We then accumulate that
2088 * chunk in one go, and then try to consume the next smaller
2091 shift = ilog2(offset) - ilog2(tk->cycle_interval);
2092 shift = max(0, shift);
2093 /* Bound shift to one less than what overflows tick_length */
2094 maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1;
2095 shift = min(shift, maxshift);
2096 while (offset >= tk->cycle_interval) {
2097 offset = logarithmic_accumulation(tk, offset, shift,
2099 if (offset < tk->cycle_interval<<shift)
2103 /* Adjust the multiplier to correct NTP error */
2104 timekeeping_adjust(tk, offset);
2107 * Finally, make sure that after the rounding
2108 * xtime_nsec isn't larger than NSEC_PER_SEC
2110 clock_set |= accumulate_nsecs_to_secs(tk);
2112 write_seqcount_begin(&tk_core.seq);
2114 * Update the real timekeeper.
2116 * We could avoid this memcpy by switching pointers, but that
2117 * requires changes to all other timekeeper usage sites as
2118 * well, i.e. move the timekeeper pointer getter into the
2119 * spinlocked/seqcount protected sections. And we trade this
2120 * memcpy under the tk_core.seq against one before we start
2123 timekeeping_update(tk, clock_set);
2124 memcpy(real_tk, tk, sizeof(*tk));
2125 /* The memcpy must come last. Do not put anything here! */
2126 write_seqcount_end(&tk_core.seq);
2128 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2130 /* Have to call _delayed version, since in irq context*/
2131 clock_was_set_delayed();
2135 * update_wall_time - Uses the current clocksource to increment the wall time
2138 void update_wall_time(void)
2140 timekeeping_advance(TK_ADV_TICK);
2144 * getboottime64 - Return the real time of system boot.
2145 * @ts: pointer to the timespec64 to be set
2147 * Returns the wall-time of boot in a timespec64.
2149 * This is based on the wall_to_monotonic offset and the total suspend
2150 * time. Calls to settimeofday will affect the value returned (which
2151 * basically means that however wrong your real time clock is at boot time,
2152 * you get the right time here).
2154 void getboottime64(struct timespec64 *ts)
2156 struct timekeeper *tk = &tk_core.timekeeper;
2157 ktime_t t = ktime_sub(tk->offs_real, tk->offs_boot);
2159 *ts = ktime_to_timespec64(t);
2161 EXPORT_SYMBOL_GPL(getboottime64);
2163 void ktime_get_coarse_real_ts64(struct timespec64 *ts)
2165 struct timekeeper *tk = &tk_core.timekeeper;
2169 seq = read_seqcount_begin(&tk_core.seq);
2172 } while (read_seqcount_retry(&tk_core.seq, seq));
2174 EXPORT_SYMBOL(ktime_get_coarse_real_ts64);
2176 void ktime_get_coarse_ts64(struct timespec64 *ts)
2178 struct timekeeper *tk = &tk_core.timekeeper;
2179 struct timespec64 now, mono;
2183 seq = read_seqcount_begin(&tk_core.seq);
2186 mono = tk->wall_to_monotonic;
2187 } while (read_seqcount_retry(&tk_core.seq, seq));
2189 set_normalized_timespec64(ts, now.tv_sec + mono.tv_sec,
2190 now.tv_nsec + mono.tv_nsec);
2192 EXPORT_SYMBOL(ktime_get_coarse_ts64);
2195 * Must hold jiffies_lock
2197 void do_timer(unsigned long ticks)
2199 jiffies_64 += ticks;
2200 calc_global_load(ticks);
2204 * ktime_get_update_offsets_now - hrtimer helper
2205 * @cwsseq: pointer to check and store the clock was set sequence number
2206 * @offs_real: pointer to storage for monotonic -> realtime offset
2207 * @offs_boot: pointer to storage for monotonic -> boottime offset
2208 * @offs_tai: pointer to storage for monotonic -> clock tai offset
2210 * Returns current monotonic time and updates the offsets if the
2211 * sequence number in @cwsseq and timekeeper.clock_was_set_seq are
2214 * Called from hrtimer_interrupt() or retrigger_next_event()
2216 ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq, ktime_t *offs_real,
2217 ktime_t *offs_boot, ktime_t *offs_tai)
2219 struct timekeeper *tk = &tk_core.timekeeper;
2225 seq = read_seqcount_begin(&tk_core.seq);
2227 base = tk->tkr_mono.base;
2228 nsecs = timekeeping_get_ns(&tk->tkr_mono);
2229 base = ktime_add_ns(base, nsecs);
2231 if (*cwsseq != tk->clock_was_set_seq) {
2232 *cwsseq = tk->clock_was_set_seq;
2233 *offs_real = tk->offs_real;
2234 *offs_boot = tk->offs_boot;
2235 *offs_tai = tk->offs_tai;
2238 /* Handle leapsecond insertion adjustments */
2239 if (unlikely(base >= tk->next_leap_ktime))
2240 *offs_real = ktime_sub(tk->offs_real, ktime_set(1, 0));
2242 } while (read_seqcount_retry(&tk_core.seq, seq));
2248 * timekeeping_validate_timex - Ensures the timex is ok for use in do_adjtimex
2250 static int timekeeping_validate_timex(const struct timex *txc)
2252 if (txc->modes & ADJ_ADJTIME) {
2253 /* singleshot must not be used with any other mode bits */
2254 if (!(txc->modes & ADJ_OFFSET_SINGLESHOT))
2256 if (!(txc->modes & ADJ_OFFSET_READONLY) &&
2257 !capable(CAP_SYS_TIME))
2260 /* In order to modify anything, you gotta be super-user! */
2261 if (txc->modes && !capable(CAP_SYS_TIME))
2264 * if the quartz is off by more than 10% then
2265 * something is VERY wrong!
2267 if (txc->modes & ADJ_TICK &&
2268 (txc->tick < 900000/USER_HZ ||
2269 txc->tick > 1100000/USER_HZ))
2273 if (txc->modes & ADJ_SETOFFSET) {
2274 /* In order to inject time, you gotta be super-user! */
2275 if (!capable(CAP_SYS_TIME))
2279 * Validate if a timespec/timeval used to inject a time
2280 * offset is valid. Offsets can be postive or negative, so
2281 * we don't check tv_sec. The value of the timeval/timespec
2282 * is the sum of its fields,but *NOTE*:
2283 * The field tv_usec/tv_nsec must always be non-negative and
2284 * we can't have more nanoseconds/microseconds than a second.
2286 if (txc->time.tv_usec < 0)
2289 if (txc->modes & ADJ_NANO) {
2290 if (txc->time.tv_usec >= NSEC_PER_SEC)
2293 if (txc->time.tv_usec >= USEC_PER_SEC)
2299 * Check for potential multiplication overflows that can
2300 * only happen on 64-bit systems:
2302 if ((txc->modes & ADJ_FREQUENCY) && (BITS_PER_LONG == 64)) {
2303 if (LLONG_MIN / PPM_SCALE > txc->freq)
2305 if (LLONG_MAX / PPM_SCALE < txc->freq)
2314 * do_adjtimex() - Accessor function to NTP __do_adjtimex function
2316 int do_adjtimex(struct timex *txc)
2318 struct timekeeper *tk = &tk_core.timekeeper;
2319 unsigned long flags;
2320 struct timespec64 ts;
2324 /* Validate the data before disabling interrupts */
2325 ret = timekeeping_validate_timex(txc);
2329 if (txc->modes & ADJ_SETOFFSET) {
2330 struct timespec64 delta;
2331 delta.tv_sec = txc->time.tv_sec;
2332 delta.tv_nsec = txc->time.tv_usec;
2333 if (!(txc->modes & ADJ_NANO))
2334 delta.tv_nsec *= 1000;
2335 ret = timekeeping_inject_offset(&delta);
2340 ktime_get_real_ts64(&ts);
2342 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2343 write_seqcount_begin(&tk_core.seq);
2345 orig_tai = tai = tk->tai_offset;
2346 ret = __do_adjtimex(txc, &ts, &tai);
2348 if (tai != orig_tai) {
2349 __timekeeping_set_tai_offset(tk, tai);
2350 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
2352 tk_update_leap_state(tk);
2354 write_seqcount_end(&tk_core.seq);
2355 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2357 /* Update the multiplier immediately if frequency was set directly */
2358 if (txc->modes & (ADJ_FREQUENCY | ADJ_TICK))
2359 timekeeping_advance(TK_ADV_FREQ);
2361 if (tai != orig_tai)
2364 ntp_notify_cmos_timer();
2369 #ifdef CONFIG_NTP_PPS
2371 * hardpps() - Accessor function to NTP __hardpps function
2373 void hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_ts)
2375 unsigned long flags;
2377 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2378 write_seqcount_begin(&tk_core.seq);
2380 __hardpps(phase_ts, raw_ts);
2382 write_seqcount_end(&tk_core.seq);
2383 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2385 EXPORT_SYMBOL(hardpps);
2386 #endif /* CONFIG_NTP_PPS */
2389 * xtime_update() - advances the timekeeping infrastructure
2390 * @ticks: number of ticks, that have elapsed since the last call.
2392 * Must be called with interrupts disabled.
2394 void xtime_update(unsigned long ticks)
2396 write_seqlock(&jiffies_lock);
2398 write_sequnlock(&jiffies_lock);