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
;
62 static struct tk_fast tk_fast_raw ____cacheline_aligned
;
64 /* flag for if timekeeping is suspended */
65 int __read_mostly timekeeping_suspended
;
67 static inline void tk_normalize_xtime(struct timekeeper
*tk
)
69 while (tk
->tkr_mono
.xtime_nsec
>= ((u64
)NSEC_PER_SEC
<< tk
->tkr_mono
.shift
)) {
70 tk
->tkr_mono
.xtime_nsec
-= (u64
)NSEC_PER_SEC
<< tk
->tkr_mono
.shift
;
75 static inline struct timespec64
tk_xtime(struct timekeeper
*tk
)
79 ts
.tv_sec
= tk
->xtime_sec
;
80 ts
.tv_nsec
= (long)(tk
->tkr_mono
.xtime_nsec
>> tk
->tkr_mono
.shift
);
84 static void tk_set_xtime(struct timekeeper
*tk
, const struct timespec64
*ts
)
86 tk
->xtime_sec
= ts
->tv_sec
;
87 tk
->tkr_mono
.xtime_nsec
= (u64
)ts
->tv_nsec
<< tk
->tkr_mono
.shift
;
90 static void tk_xtime_add(struct timekeeper
*tk
, const struct timespec64
*ts
)
92 tk
->xtime_sec
+= ts
->tv_sec
;
93 tk
->tkr_mono
.xtime_nsec
+= (u64
)ts
->tv_nsec
<< tk
->tkr_mono
.shift
;
94 tk_normalize_xtime(tk
);
97 static void tk_set_wall_to_mono(struct timekeeper
*tk
, struct timespec64 wtm
)
99 struct timespec64 tmp
;
102 * Verify consistency of: offset_real = -wall_to_monotonic
103 * before modifying anything
105 set_normalized_timespec64(&tmp
, -tk
->wall_to_monotonic
.tv_sec
,
106 -tk
->wall_to_monotonic
.tv_nsec
);
107 WARN_ON_ONCE(tk
->offs_real
.tv64
!= timespec64_to_ktime(tmp
).tv64
);
108 tk
->wall_to_monotonic
= wtm
;
109 set_normalized_timespec64(&tmp
, -wtm
.tv_sec
, -wtm
.tv_nsec
);
110 tk
->offs_real
= timespec64_to_ktime(tmp
);
111 tk
->offs_tai
= ktime_add(tk
->offs_real
, ktime_set(tk
->tai_offset
, 0));
114 static inline void tk_update_sleep_time(struct timekeeper
*tk
, ktime_t delta
)
116 tk
->offs_boot
= ktime_add(tk
->offs_boot
, delta
);
119 #ifdef CONFIG_DEBUG_TIMEKEEPING
120 #define WARNING_FREQ (HZ*300) /* 5 minute rate-limiting */
122 static void timekeeping_check_update(struct timekeeper
*tk
, cycle_t offset
)
125 cycle_t max_cycles
= tk
->tkr_mono
.clock
->max_cycles
;
126 const char *name
= tk
->tkr_mono
.clock
->name
;
128 if (offset
> max_cycles
) {
129 printk_deferred("WARNING: timekeeping: Cycle offset (%lld) is larger than allowed by the '%s' clock's max_cycles value (%lld): time overflow danger\n",
130 offset
, name
, max_cycles
);
131 printk_deferred(" timekeeping: Your kernel is sick, but tries to cope by capping time updates\n");
133 if (offset
> (max_cycles
>> 1)) {
134 printk_deferred("INFO: timekeeping: Cycle offset (%lld) is larger than the '%s' clock's 50%% safety margin (%lld)\n",
135 offset
, name
, max_cycles
>> 1);
136 printk_deferred(" timekeeping: Your kernel is still fine, but is feeling a bit nervous\n");
140 if (tk
->underflow_seen
) {
141 if (jiffies
- tk
->last_warning
> WARNING_FREQ
) {
142 printk_deferred("WARNING: Underflow in clocksource '%s' observed, time update ignored.\n", name
);
143 printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
144 printk_deferred(" Your kernel is probably still fine.\n");
145 tk
->last_warning
= jiffies
;
147 tk
->underflow_seen
= 0;
150 if (tk
->overflow_seen
) {
151 if (jiffies
- tk
->last_warning
> WARNING_FREQ
) {
152 printk_deferred("WARNING: Overflow in clocksource '%s' observed, time update capped.\n", name
);
153 printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
154 printk_deferred(" Your kernel is probably still fine.\n");
155 tk
->last_warning
= jiffies
;
157 tk
->overflow_seen
= 0;
161 static inline cycle_t
timekeeping_get_delta(struct tk_read_base
*tkr
)
163 struct timekeeper
*tk
= &tk_core
.timekeeper
;
164 cycle_t now
, last
, mask
, max
, delta
;
168 * Since we're called holding a seqlock, the data may shift
169 * under us while we're doing the calculation. This can cause
170 * false positives, since we'd note a problem but throw the
171 * results away. So nest another seqlock here to atomically
172 * grab the points we are checking with.
175 seq
= read_seqcount_begin(&tk_core
.seq
);
176 now
= tkr
->read(tkr
->clock
);
177 last
= tkr
->cycle_last
;
179 max
= tkr
->clock
->max_cycles
;
180 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
182 delta
= clocksource_delta(now
, last
, mask
);
185 * Try to catch underflows by checking if we are seeing small
186 * mask-relative negative values.
188 if (unlikely((~delta
& mask
) < (mask
>> 3))) {
189 tk
->underflow_seen
= 1;
193 /* Cap delta value to the max_cycles values to avoid mult overflows */
194 if (unlikely(delta
> max
)) {
195 tk
->overflow_seen
= 1;
196 delta
= tkr
->clock
->max_cycles
;
202 static inline void timekeeping_check_update(struct timekeeper
*tk
, cycle_t offset
)
205 static inline cycle_t
timekeeping_get_delta(struct tk_read_base
*tkr
)
207 cycle_t cycle_now
, delta
;
209 /* read clocksource */
210 cycle_now
= tkr
->read(tkr
->clock
);
212 /* calculate the delta since the last update_wall_time */
213 delta
= clocksource_delta(cycle_now
, tkr
->cycle_last
, tkr
->mask
);
220 * tk_setup_internals - Set up internals to use clocksource clock.
222 * @tk: The target timekeeper to setup.
223 * @clock: Pointer to clocksource.
225 * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
226 * pair and interval request.
228 * Unless you're the timekeeping code, you should not be using this!
230 static void tk_setup_internals(struct timekeeper
*tk
, struct clocksource
*clock
)
233 u64 tmp
, ntpinterval
;
234 struct clocksource
*old_clock
;
236 ++tk
->cs_was_changed_seq
;
237 old_clock
= tk
->tkr_mono
.clock
;
238 tk
->tkr_mono
.clock
= clock
;
239 tk
->tkr_mono
.read
= clock
->read
;
240 tk
->tkr_mono
.mask
= clock
->mask
;
241 tk
->tkr_mono
.cycle_last
= tk
->tkr_mono
.read(clock
);
243 tk
->tkr_raw
.clock
= clock
;
244 tk
->tkr_raw
.read
= clock
->read
;
245 tk
->tkr_raw
.mask
= clock
->mask
;
246 tk
->tkr_raw
.cycle_last
= tk
->tkr_mono
.cycle_last
;
248 /* Do the ns -> cycle conversion first, using original mult */
249 tmp
= NTP_INTERVAL_LENGTH
;
250 tmp
<<= clock
->shift
;
252 tmp
+= clock
->mult
/2;
253 do_div(tmp
, clock
->mult
);
257 interval
= (cycle_t
) tmp
;
258 tk
->cycle_interval
= interval
;
260 /* Go back from cycles -> shifted ns */
261 tk
->xtime_interval
= (u64
) interval
* clock
->mult
;
262 tk
->xtime_remainder
= ntpinterval
- tk
->xtime_interval
;
264 ((u64
) interval
* clock
->mult
) >> clock
->shift
;
266 /* if changing clocks, convert xtime_nsec shift units */
268 int shift_change
= clock
->shift
- old_clock
->shift
;
269 if (shift_change
< 0)
270 tk
->tkr_mono
.xtime_nsec
>>= -shift_change
;
272 tk
->tkr_mono
.xtime_nsec
<<= shift_change
;
274 tk
->tkr_raw
.xtime_nsec
= 0;
276 tk
->tkr_mono
.shift
= clock
->shift
;
277 tk
->tkr_raw
.shift
= clock
->shift
;
280 tk
->ntp_error_shift
= NTP_SCALE_SHIFT
- clock
->shift
;
281 tk
->ntp_tick
= ntpinterval
<< tk
->ntp_error_shift
;
284 * The timekeeper keeps its own mult values for the currently
285 * active clocksource. These value will be adjusted via NTP
286 * to counteract clock drifting.
288 tk
->tkr_mono
.mult
= clock
->mult
;
289 tk
->tkr_raw
.mult
= clock
->mult
;
290 tk
->ntp_err_mult
= 0;
293 /* Timekeeper helper functions. */
295 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
296 static u32
default_arch_gettimeoffset(void) { return 0; }
297 u32 (*arch_gettimeoffset
)(void) = default_arch_gettimeoffset
;
299 static inline u32
arch_gettimeoffset(void) { return 0; }
302 static inline s64
timekeeping_delta_to_ns(struct tk_read_base
*tkr
,
307 nsec
= delta
* tkr
->mult
+ tkr
->xtime_nsec
;
310 /* If arch requires, add in get_arch_timeoffset() */
311 return nsec
+ arch_gettimeoffset();
314 static inline s64
timekeeping_get_ns(struct tk_read_base
*tkr
)
318 delta
= timekeeping_get_delta(tkr
);
319 return timekeeping_delta_to_ns(tkr
, delta
);
322 static inline s64
timekeeping_cycles_to_ns(struct tk_read_base
*tkr
,
327 /* calculate the delta since the last update_wall_time */
328 delta
= clocksource_delta(cycles
, tkr
->cycle_last
, tkr
->mask
);
329 return timekeeping_delta_to_ns(tkr
, delta
);
333 * update_fast_timekeeper - Update the fast and NMI safe monotonic timekeeper.
334 * @tkr: Timekeeping readout base from which we take the update
336 * We want to use this from any context including NMI and tracing /
337 * instrumenting the timekeeping code itself.
339 * Employ the latch technique; see @raw_write_seqcount_latch.
341 * So if a NMI hits the update of base[0] then it will use base[1]
342 * which is still consistent. In the worst case this can result is a
343 * slightly wrong timestamp (a few nanoseconds). See
344 * @ktime_get_mono_fast_ns.
346 static void update_fast_timekeeper(struct tk_read_base
*tkr
, struct tk_fast
*tkf
)
348 struct tk_read_base
*base
= tkf
->base
;
350 /* Force readers off to base[1] */
351 raw_write_seqcount_latch(&tkf
->seq
);
354 memcpy(base
, tkr
, sizeof(*base
));
356 /* Force readers back to base[0] */
357 raw_write_seqcount_latch(&tkf
->seq
);
360 memcpy(base
+ 1, base
, sizeof(*base
));
364 * ktime_get_mono_fast_ns - Fast NMI safe access to clock monotonic
366 * This timestamp is not guaranteed to be monotonic across an update.
367 * The timestamp is calculated by:
369 * now = base_mono + clock_delta * slope
371 * So if the update lowers the slope, readers who are forced to the
372 * not yet updated second array are still using the old steeper slope.
381 * |12345678---> reader order
387 * So reader 6 will observe time going backwards versus reader 5.
389 * While other CPUs are likely to be able observe that, the only way
390 * for a CPU local observation is when an NMI hits in the middle of
391 * the update. Timestamps taken from that NMI context might be ahead
392 * of the following timestamps. Callers need to be aware of that and
395 static __always_inline u64
__ktime_get_fast_ns(struct tk_fast
*tkf
)
397 struct tk_read_base
*tkr
;
402 seq
= raw_read_seqcount_latch(&tkf
->seq
);
403 tkr
= tkf
->base
+ (seq
& 0x01);
404 now
= ktime_to_ns(tkr
->base
);
406 now
+= clocksource_delta(tkr
->read(tkr
->clock
),
407 tkr
->cycle_last
, tkr
->mask
);
408 } while (read_seqcount_retry(&tkf
->seq
, seq
));
413 u64
ktime_get_mono_fast_ns(void)
415 return __ktime_get_fast_ns(&tk_fast_mono
);
417 EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns
);
419 u64
ktime_get_raw_fast_ns(void)
421 return __ktime_get_fast_ns(&tk_fast_raw
);
423 EXPORT_SYMBOL_GPL(ktime_get_raw_fast_ns
);
425 /* Suspend-time cycles value for halted fast timekeeper. */
426 static cycle_t cycles_at_suspend
;
428 static cycle_t
dummy_clock_read(struct clocksource
*cs
)
430 return cycles_at_suspend
;
434 * halt_fast_timekeeper - Prevent fast timekeeper from accessing clocksource.
435 * @tk: Timekeeper to snapshot.
437 * It generally is unsafe to access the clocksource after timekeeping has been
438 * suspended, so take a snapshot of the readout base of @tk and use it as the
439 * fast timekeeper's readout base while suspended. It will return the same
440 * number of cycles every time until timekeeping is resumed at which time the
441 * proper readout base for the fast timekeeper will be restored automatically.
443 static void halt_fast_timekeeper(struct timekeeper
*tk
)
445 static struct tk_read_base tkr_dummy
;
446 struct tk_read_base
*tkr
= &tk
->tkr_mono
;
448 memcpy(&tkr_dummy
, tkr
, sizeof(tkr_dummy
));
449 cycles_at_suspend
= tkr
->read(tkr
->clock
);
450 tkr_dummy
.read
= dummy_clock_read
;
451 update_fast_timekeeper(&tkr_dummy
, &tk_fast_mono
);
454 memcpy(&tkr_dummy
, tkr
, sizeof(tkr_dummy
));
455 tkr_dummy
.read
= dummy_clock_read
;
456 update_fast_timekeeper(&tkr_dummy
, &tk_fast_raw
);
459 #ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD
461 static inline void update_vsyscall(struct timekeeper
*tk
)
463 struct timespec xt
, wm
;
465 xt
= timespec64_to_timespec(tk_xtime(tk
));
466 wm
= timespec64_to_timespec(tk
->wall_to_monotonic
);
467 update_vsyscall_old(&xt
, &wm
, tk
->tkr_mono
.clock
, tk
->tkr_mono
.mult
,
468 tk
->tkr_mono
.cycle_last
);
471 static inline void old_vsyscall_fixup(struct timekeeper
*tk
)
476 * Store only full nanoseconds into xtime_nsec after rounding
477 * it up and add the remainder to the error difference.
478 * XXX - This is necessary to avoid small 1ns inconsistnecies caused
479 * by truncating the remainder in vsyscalls. However, it causes
480 * additional work to be done in timekeeping_adjust(). Once
481 * the vsyscall implementations are converted to use xtime_nsec
482 * (shifted nanoseconds), and CONFIG_GENERIC_TIME_VSYSCALL_OLD
483 * users are removed, this can be killed.
485 remainder
= tk
->tkr_mono
.xtime_nsec
& ((1ULL << tk
->tkr_mono
.shift
) - 1);
486 if (remainder
!= 0) {
487 tk
->tkr_mono
.xtime_nsec
-= remainder
;
488 tk
->tkr_mono
.xtime_nsec
+= 1ULL << tk
->tkr_mono
.shift
;
489 tk
->ntp_error
+= remainder
<< tk
->ntp_error_shift
;
490 tk
->ntp_error
-= (1ULL << tk
->tkr_mono
.shift
) << tk
->ntp_error_shift
;
494 #define old_vsyscall_fixup(tk)
497 static RAW_NOTIFIER_HEAD(pvclock_gtod_chain
);
499 static void update_pvclock_gtod(struct timekeeper
*tk
, bool was_set
)
501 raw_notifier_call_chain(&pvclock_gtod_chain
, was_set
, tk
);
505 * pvclock_gtod_register_notifier - register a pvclock timedata update listener
507 int pvclock_gtod_register_notifier(struct notifier_block
*nb
)
509 struct timekeeper
*tk
= &tk_core
.timekeeper
;
513 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
514 ret
= raw_notifier_chain_register(&pvclock_gtod_chain
, nb
);
515 update_pvclock_gtod(tk
, true);
516 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
520 EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier
);
523 * pvclock_gtod_unregister_notifier - unregister a pvclock
524 * timedata update listener
526 int pvclock_gtod_unregister_notifier(struct notifier_block
*nb
)
531 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
532 ret
= raw_notifier_chain_unregister(&pvclock_gtod_chain
, nb
);
533 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
537 EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier
);
540 * tk_update_leap_state - helper to update the next_leap_ktime
542 static inline void tk_update_leap_state(struct timekeeper
*tk
)
544 tk
->next_leap_ktime
= ntp_get_next_leap();
545 if (tk
->next_leap_ktime
.tv64
!= KTIME_MAX
)
546 /* Convert to monotonic time */
547 tk
->next_leap_ktime
= ktime_sub(tk
->next_leap_ktime
, tk
->offs_real
);
551 * Update the ktime_t based scalar nsec members of the timekeeper
553 static inline void tk_update_ktime_data(struct timekeeper
*tk
)
559 * The xtime based monotonic readout is:
560 * nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();
561 * The ktime based monotonic readout is:
562 * nsec = base_mono + now();
563 * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec
565 seconds
= (u64
)(tk
->xtime_sec
+ tk
->wall_to_monotonic
.tv_sec
);
566 nsec
= (u32
) tk
->wall_to_monotonic
.tv_nsec
;
567 tk
->tkr_mono
.base
= ns_to_ktime(seconds
* NSEC_PER_SEC
+ nsec
);
569 /* Update the monotonic raw base */
570 tk
->tkr_raw
.base
= timespec64_to_ktime(tk
->raw_time
);
573 * The sum of the nanoseconds portions of xtime and
574 * wall_to_monotonic can be greater/equal one second. Take
575 * this into account before updating tk->ktime_sec.
577 nsec
+= (u32
)(tk
->tkr_mono
.xtime_nsec
>> tk
->tkr_mono
.shift
);
578 if (nsec
>= NSEC_PER_SEC
)
580 tk
->ktime_sec
= seconds
;
583 /* must hold timekeeper_lock */
584 static void timekeeping_update(struct timekeeper
*tk
, unsigned int action
)
586 if (action
& TK_CLEAR_NTP
) {
591 tk_update_leap_state(tk
);
592 tk_update_ktime_data(tk
);
595 update_pvclock_gtod(tk
, action
& TK_CLOCK_WAS_SET
);
597 update_fast_timekeeper(&tk
->tkr_mono
, &tk_fast_mono
);
598 update_fast_timekeeper(&tk
->tkr_raw
, &tk_fast_raw
);
600 if (action
& TK_CLOCK_WAS_SET
)
601 tk
->clock_was_set_seq
++;
603 * The mirroring of the data to the shadow-timekeeper needs
604 * to happen last here to ensure we don't over-write the
605 * timekeeper structure on the next update with stale data
607 if (action
& TK_MIRROR
)
608 memcpy(&shadow_timekeeper
, &tk_core
.timekeeper
,
609 sizeof(tk_core
.timekeeper
));
613 * timekeeping_forward_now - update clock to the current time
615 * Forward the current clock to update its state since the last call to
616 * update_wall_time(). This is useful before significant clock changes,
617 * as it avoids having to deal with this time offset explicitly.
619 static void timekeeping_forward_now(struct timekeeper
*tk
)
621 struct clocksource
*clock
= tk
->tkr_mono
.clock
;
622 cycle_t cycle_now
, delta
;
625 cycle_now
= tk
->tkr_mono
.read(clock
);
626 delta
= clocksource_delta(cycle_now
, tk
->tkr_mono
.cycle_last
, tk
->tkr_mono
.mask
);
627 tk
->tkr_mono
.cycle_last
= cycle_now
;
628 tk
->tkr_raw
.cycle_last
= cycle_now
;
630 tk
->tkr_mono
.xtime_nsec
+= delta
* tk
->tkr_mono
.mult
;
632 /* If arch requires, add in get_arch_timeoffset() */
633 tk
->tkr_mono
.xtime_nsec
+= (u64
)arch_gettimeoffset() << tk
->tkr_mono
.shift
;
635 tk_normalize_xtime(tk
);
637 nsec
= clocksource_cyc2ns(delta
, tk
->tkr_raw
.mult
, tk
->tkr_raw
.shift
);
638 timespec64_add_ns(&tk
->raw_time
, nsec
);
642 * __getnstimeofday64 - Returns the time of day in a timespec64.
643 * @ts: pointer to the timespec to be set
645 * Updates the time of day in the timespec.
646 * Returns 0 on success, or -ve when suspended (timespec will be undefined).
648 int __getnstimeofday64(struct timespec64
*ts
)
650 struct timekeeper
*tk
= &tk_core
.timekeeper
;
655 seq
= read_seqcount_begin(&tk_core
.seq
);
657 ts
->tv_sec
= tk
->xtime_sec
;
658 nsecs
= timekeeping_get_ns(&tk
->tkr_mono
);
660 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
663 timespec64_add_ns(ts
, nsecs
);
666 * Do not bail out early, in case there were callers still using
667 * the value, even in the face of the WARN_ON.
669 if (unlikely(timekeeping_suspended
))
673 EXPORT_SYMBOL(__getnstimeofday64
);
676 * getnstimeofday64 - Returns the time of day in a timespec64.
677 * @ts: pointer to the timespec64 to be set
679 * Returns the time of day in a timespec64 (WARN if suspended).
681 void getnstimeofday64(struct timespec64
*ts
)
683 WARN_ON(__getnstimeofday64(ts
));
685 EXPORT_SYMBOL(getnstimeofday64
);
687 ktime_t
ktime_get(void)
689 struct timekeeper
*tk
= &tk_core
.timekeeper
;
694 WARN_ON(timekeeping_suspended
);
697 seq
= read_seqcount_begin(&tk_core
.seq
);
698 base
= tk
->tkr_mono
.base
;
699 nsecs
= timekeeping_get_ns(&tk
->tkr_mono
);
701 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
703 return ktime_add_ns(base
, nsecs
);
705 EXPORT_SYMBOL_GPL(ktime_get
);
707 u32
ktime_get_resolution_ns(void)
709 struct timekeeper
*tk
= &tk_core
.timekeeper
;
713 WARN_ON(timekeeping_suspended
);
716 seq
= read_seqcount_begin(&tk_core
.seq
);
717 nsecs
= tk
->tkr_mono
.mult
>> tk
->tkr_mono
.shift
;
718 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
722 EXPORT_SYMBOL_GPL(ktime_get_resolution_ns
);
724 static ktime_t
*offsets
[TK_OFFS_MAX
] = {
725 [TK_OFFS_REAL
] = &tk_core
.timekeeper
.offs_real
,
726 [TK_OFFS_BOOT
] = &tk_core
.timekeeper
.offs_boot
,
727 [TK_OFFS_TAI
] = &tk_core
.timekeeper
.offs_tai
,
730 ktime_t
ktime_get_with_offset(enum tk_offsets offs
)
732 struct timekeeper
*tk
= &tk_core
.timekeeper
;
734 ktime_t base
, *offset
= offsets
[offs
];
737 WARN_ON(timekeeping_suspended
);
740 seq
= read_seqcount_begin(&tk_core
.seq
);
741 base
= ktime_add(tk
->tkr_mono
.base
, *offset
);
742 nsecs
= timekeeping_get_ns(&tk
->tkr_mono
);
744 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
746 return ktime_add_ns(base
, nsecs
);
749 EXPORT_SYMBOL_GPL(ktime_get_with_offset
);
752 * ktime_mono_to_any() - convert mononotic time to any other time
753 * @tmono: time to convert.
754 * @offs: which offset to use
756 ktime_t
ktime_mono_to_any(ktime_t tmono
, enum tk_offsets offs
)
758 ktime_t
*offset
= offsets
[offs
];
763 seq
= read_seqcount_begin(&tk_core
.seq
);
764 tconv
= ktime_add(tmono
, *offset
);
765 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
769 EXPORT_SYMBOL_GPL(ktime_mono_to_any
);
772 * ktime_get_raw - Returns the raw monotonic time in ktime_t format
774 ktime_t
ktime_get_raw(void)
776 struct timekeeper
*tk
= &tk_core
.timekeeper
;
782 seq
= read_seqcount_begin(&tk_core
.seq
);
783 base
= tk
->tkr_raw
.base
;
784 nsecs
= timekeeping_get_ns(&tk
->tkr_raw
);
786 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
788 return ktime_add_ns(base
, nsecs
);
790 EXPORT_SYMBOL_GPL(ktime_get_raw
);
793 * ktime_get_ts64 - get the monotonic clock in timespec64 format
794 * @ts: pointer to timespec variable
796 * The function calculates the monotonic clock from the realtime
797 * clock and the wall_to_monotonic offset and stores the result
798 * in normalized timespec64 format in the variable pointed to by @ts.
800 void ktime_get_ts64(struct timespec64
*ts
)
802 struct timekeeper
*tk
= &tk_core
.timekeeper
;
803 struct timespec64 tomono
;
807 WARN_ON(timekeeping_suspended
);
810 seq
= read_seqcount_begin(&tk_core
.seq
);
811 ts
->tv_sec
= tk
->xtime_sec
;
812 nsec
= timekeeping_get_ns(&tk
->tkr_mono
);
813 tomono
= tk
->wall_to_monotonic
;
815 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
817 ts
->tv_sec
+= tomono
.tv_sec
;
819 timespec64_add_ns(ts
, nsec
+ tomono
.tv_nsec
);
821 EXPORT_SYMBOL_GPL(ktime_get_ts64
);
824 * ktime_get_seconds - Get the seconds portion of CLOCK_MONOTONIC
826 * Returns the seconds portion of CLOCK_MONOTONIC with a single non
827 * serialized read. tk->ktime_sec is of type 'unsigned long' so this
828 * works on both 32 and 64 bit systems. On 32 bit systems the readout
829 * covers ~136 years of uptime which should be enough to prevent
830 * premature wrap arounds.
832 time64_t
ktime_get_seconds(void)
834 struct timekeeper
*tk
= &tk_core
.timekeeper
;
836 WARN_ON(timekeeping_suspended
);
837 return tk
->ktime_sec
;
839 EXPORT_SYMBOL_GPL(ktime_get_seconds
);
842 * ktime_get_real_seconds - Get the seconds portion of CLOCK_REALTIME
844 * Returns the wall clock seconds since 1970. This replaces the
845 * get_seconds() interface which is not y2038 safe on 32bit systems.
847 * For 64bit systems the fast access to tk->xtime_sec is preserved. On
848 * 32bit systems the access must be protected with the sequence
849 * counter to provide "atomic" access to the 64bit tk->xtime_sec
852 time64_t
ktime_get_real_seconds(void)
854 struct timekeeper
*tk
= &tk_core
.timekeeper
;
858 if (IS_ENABLED(CONFIG_64BIT
))
859 return tk
->xtime_sec
;
862 seq
= read_seqcount_begin(&tk_core
.seq
);
863 seconds
= tk
->xtime_sec
;
865 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
869 EXPORT_SYMBOL_GPL(ktime_get_real_seconds
);
872 * __ktime_get_real_seconds - The same as ktime_get_real_seconds
873 * but without the sequence counter protect. This internal function
874 * is called just when timekeeping lock is already held.
876 time64_t
__ktime_get_real_seconds(void)
878 struct timekeeper
*tk
= &tk_core
.timekeeper
;
880 return tk
->xtime_sec
;
884 * ktime_get_snapshot - snapshots the realtime/monotonic raw clocks with counter
885 * @systime_snapshot: pointer to struct receiving the system time snapshot
887 void ktime_get_snapshot(struct system_time_snapshot
*systime_snapshot
)
889 struct timekeeper
*tk
= &tk_core
.timekeeper
;
897 WARN_ON_ONCE(timekeeping_suspended
);
900 seq
= read_seqcount_begin(&tk_core
.seq
);
902 now
= tk
->tkr_mono
.read(tk
->tkr_mono
.clock
);
903 systime_snapshot
->cs_was_changed_seq
= tk
->cs_was_changed_seq
;
904 systime_snapshot
->clock_was_set_seq
= tk
->clock_was_set_seq
;
905 base_real
= ktime_add(tk
->tkr_mono
.base
,
906 tk_core
.timekeeper
.offs_real
);
907 base_raw
= tk
->tkr_raw
.base
;
908 nsec_real
= timekeeping_cycles_to_ns(&tk
->tkr_mono
, now
);
909 nsec_raw
= timekeeping_cycles_to_ns(&tk
->tkr_raw
, now
);
910 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
912 systime_snapshot
->cycles
= now
;
913 systime_snapshot
->real
= ktime_add_ns(base_real
, nsec_real
);
914 systime_snapshot
->raw
= ktime_add_ns(base_raw
, nsec_raw
);
916 EXPORT_SYMBOL_GPL(ktime_get_snapshot
);
918 /* Scale base by mult/div checking for overflow */
919 static int scale64_check_overflow(u64 mult
, u64 div
, u64
*base
)
923 tmp
= div64_u64_rem(*base
, div
, &rem
);
925 if (((int)sizeof(u64
)*8 - fls64(mult
) < fls64(tmp
)) ||
926 ((int)sizeof(u64
)*8 - fls64(mult
) < fls64(rem
)))
937 * adjust_historical_crosststamp - adjust crosstimestamp previous to current interval
938 * @history: Snapshot representing start of history
939 * @partial_history_cycles: Cycle offset into history (fractional part)
940 * @total_history_cycles: Total history length in cycles
941 * @discontinuity: True indicates clock was set on history period
942 * @ts: Cross timestamp that should be adjusted using
943 * partial/total ratio
945 * Helper function used by get_device_system_crosststamp() to correct the
946 * crosstimestamp corresponding to the start of the current interval to the
947 * system counter value (timestamp point) provided by the driver. The
948 * total_history_* quantities are the total history starting at the provided
949 * reference point and ending at the start of the current interval. The cycle
950 * count between the driver timestamp point and the start of the current
951 * interval is partial_history_cycles.
953 static int adjust_historical_crosststamp(struct system_time_snapshot
*history
,
954 cycle_t partial_history_cycles
,
955 cycle_t total_history_cycles
,
957 struct system_device_crosststamp
*ts
)
959 struct timekeeper
*tk
= &tk_core
.timekeeper
;
960 u64 corr_raw
, corr_real
;
964 if (total_history_cycles
== 0 || partial_history_cycles
== 0)
967 /* Interpolate shortest distance from beginning or end of history */
968 interp_forward
= partial_history_cycles
> total_history_cycles
/2 ?
970 partial_history_cycles
= interp_forward
?
971 total_history_cycles
- partial_history_cycles
:
972 partial_history_cycles
;
975 * Scale the monotonic raw time delta by:
976 * partial_history_cycles / total_history_cycles
978 corr_raw
= (u64
)ktime_to_ns(
979 ktime_sub(ts
->sys_monoraw
, history
->raw
));
980 ret
= scale64_check_overflow(partial_history_cycles
,
981 total_history_cycles
, &corr_raw
);
986 * If there is a discontinuity in the history, scale monotonic raw
988 * mult(real)/mult(raw) yielding the realtime correction
989 * Otherwise, calculate the realtime correction similar to monotonic
993 corr_real
= mul_u64_u32_div
994 (corr_raw
, tk
->tkr_mono
.mult
, tk
->tkr_raw
.mult
);
996 corr_real
= (u64
)ktime_to_ns(
997 ktime_sub(ts
->sys_realtime
, history
->real
));
998 ret
= scale64_check_overflow(partial_history_cycles
,
999 total_history_cycles
, &corr_real
);
1004 /* Fixup monotonic raw and real time time values */
1005 if (interp_forward
) {
1006 ts
->sys_monoraw
= ktime_add_ns(history
->raw
, corr_raw
);
1007 ts
->sys_realtime
= ktime_add_ns(history
->real
, corr_real
);
1009 ts
->sys_monoraw
= ktime_sub_ns(ts
->sys_monoraw
, corr_raw
);
1010 ts
->sys_realtime
= ktime_sub_ns(ts
->sys_realtime
, corr_real
);
1017 * cycle_between - true if test occurs chronologically between before and after
1019 static bool cycle_between(cycle_t before
, cycle_t test
, cycle_t after
)
1021 if (test
> before
&& test
< after
)
1023 if (test
< before
&& before
> after
)
1029 * get_device_system_crosststamp - Synchronously capture system/device timestamp
1030 * @get_time_fn: Callback to get simultaneous device time and
1031 * system counter from the device driver
1032 * @ctx: Context passed to get_time_fn()
1033 * @history_begin: Historical reference point used to interpolate system
1034 * time when counter provided by the driver is before the current interval
1035 * @xtstamp: Receives simultaneously captured system and device time
1037 * Reads a timestamp from a device and correlates it to system time
1039 int get_device_system_crosststamp(int (*get_time_fn
)
1040 (ktime_t
*device_time
,
1041 struct system_counterval_t
*sys_counterval
,
1044 struct system_time_snapshot
*history_begin
,
1045 struct system_device_crosststamp
*xtstamp
)
1047 struct system_counterval_t system_counterval
;
1048 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1049 cycle_t cycles
, now
, interval_start
;
1050 unsigned int clock_was_set_seq
= 0;
1051 ktime_t base_real
, base_raw
;
1052 s64 nsec_real
, nsec_raw
;
1053 u8 cs_was_changed_seq
;
1059 seq
= read_seqcount_begin(&tk_core
.seq
);
1061 * Try to synchronously capture device time and a system
1062 * counter value calling back into the device driver
1064 ret
= get_time_fn(&xtstamp
->device
, &system_counterval
, ctx
);
1069 * Verify that the clocksource associated with the captured
1070 * system counter value is the same as the currently installed
1071 * timekeeper clocksource
1073 if (tk
->tkr_mono
.clock
!= system_counterval
.cs
)
1075 cycles
= system_counterval
.cycles
;
1078 * Check whether the system counter value provided by the
1079 * device driver is on the current timekeeping interval.
1081 now
= tk
->tkr_mono
.read(tk
->tkr_mono
.clock
);
1082 interval_start
= tk
->tkr_mono
.cycle_last
;
1083 if (!cycle_between(interval_start
, cycles
, now
)) {
1084 clock_was_set_seq
= tk
->clock_was_set_seq
;
1085 cs_was_changed_seq
= tk
->cs_was_changed_seq
;
1086 cycles
= interval_start
;
1092 base_real
= ktime_add(tk
->tkr_mono
.base
,
1093 tk_core
.timekeeper
.offs_real
);
1094 base_raw
= tk
->tkr_raw
.base
;
1096 nsec_real
= timekeeping_cycles_to_ns(&tk
->tkr_mono
,
1097 system_counterval
.cycles
);
1098 nsec_raw
= timekeeping_cycles_to_ns(&tk
->tkr_raw
,
1099 system_counterval
.cycles
);
1100 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1102 xtstamp
->sys_realtime
= ktime_add_ns(base_real
, nsec_real
);
1103 xtstamp
->sys_monoraw
= ktime_add_ns(base_raw
, nsec_raw
);
1106 * Interpolate if necessary, adjusting back from the start of the
1110 cycle_t partial_history_cycles
, total_history_cycles
;
1114 * Check that the counter value occurs after the provided
1115 * history reference and that the history doesn't cross a
1116 * clocksource change
1118 if (!history_begin
||
1119 !cycle_between(history_begin
->cycles
,
1120 system_counterval
.cycles
, cycles
) ||
1121 history_begin
->cs_was_changed_seq
!= cs_was_changed_seq
)
1123 partial_history_cycles
= cycles
- system_counterval
.cycles
;
1124 total_history_cycles
= cycles
- history_begin
->cycles
;
1126 history_begin
->clock_was_set_seq
!= clock_was_set_seq
;
1128 ret
= adjust_historical_crosststamp(history_begin
,
1129 partial_history_cycles
,
1130 total_history_cycles
,
1131 discontinuity
, xtstamp
);
1138 EXPORT_SYMBOL_GPL(get_device_system_crosststamp
);
1141 * do_gettimeofday - Returns the time of day in a timeval
1142 * @tv: pointer to the timeval to be set
1144 * NOTE: Users should be converted to using getnstimeofday()
1146 void do_gettimeofday(struct timeval
*tv
)
1148 struct timespec64 now
;
1150 getnstimeofday64(&now
);
1151 tv
->tv_sec
= now
.tv_sec
;
1152 tv
->tv_usec
= now
.tv_nsec
/1000;
1154 EXPORT_SYMBOL(do_gettimeofday
);
1157 * do_settimeofday64 - Sets the time of day.
1158 * @ts: pointer to the timespec64 variable containing the new time
1160 * Sets the time of day to the new time and update NTP and notify hrtimers
1162 int do_settimeofday64(const struct timespec64
*ts
)
1164 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1165 struct timespec64 ts_delta
, xt
;
1166 unsigned long flags
;
1169 if (!timespec64_valid_strict(ts
))
1172 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1173 write_seqcount_begin(&tk_core
.seq
);
1175 timekeeping_forward_now(tk
);
1178 ts_delta
.tv_sec
= ts
->tv_sec
- xt
.tv_sec
;
1179 ts_delta
.tv_nsec
= ts
->tv_nsec
- xt
.tv_nsec
;
1181 if (timespec64_compare(&tk
->wall_to_monotonic
, &ts_delta
) > 0) {
1186 tk_set_wall_to_mono(tk
, timespec64_sub(tk
->wall_to_monotonic
, ts_delta
));
1188 tk_set_xtime(tk
, ts
);
1190 timekeeping_update(tk
, TK_CLEAR_NTP
| TK_MIRROR
| TK_CLOCK_WAS_SET
);
1192 write_seqcount_end(&tk_core
.seq
);
1193 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1195 /* signal hrtimers about time change */
1200 EXPORT_SYMBOL(do_settimeofday64
);
1203 * timekeeping_inject_offset - Adds or subtracts from the current time.
1204 * @tv: pointer to the timespec variable containing the offset
1206 * Adds or subtracts an offset value from the current time.
1208 int timekeeping_inject_offset(struct timespec
*ts
)
1210 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1211 unsigned long flags
;
1212 struct timespec64 ts64
, tmp
;
1215 if (!timespec_inject_offset_valid(ts
))
1218 ts64
= timespec_to_timespec64(*ts
);
1220 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1221 write_seqcount_begin(&tk_core
.seq
);
1223 timekeeping_forward_now(tk
);
1225 /* Make sure the proposed value is valid */
1226 tmp
= timespec64_add(tk_xtime(tk
), ts64
);
1227 if (timespec64_compare(&tk
->wall_to_monotonic
, &ts64
) > 0 ||
1228 !timespec64_valid_strict(&tmp
)) {
1233 tk_xtime_add(tk
, &ts64
);
1234 tk_set_wall_to_mono(tk
, timespec64_sub(tk
->wall_to_monotonic
, ts64
));
1236 error
: /* even if we error out, we forwarded the time, so call update */
1237 timekeeping_update(tk
, TK_CLEAR_NTP
| TK_MIRROR
| TK_CLOCK_WAS_SET
);
1239 write_seqcount_end(&tk_core
.seq
);
1240 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1242 /* signal hrtimers about time change */
1247 EXPORT_SYMBOL(timekeeping_inject_offset
);
1251 * timekeeping_get_tai_offset - Returns current TAI offset from UTC
1254 s32
timekeeping_get_tai_offset(void)
1256 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1261 seq
= read_seqcount_begin(&tk_core
.seq
);
1262 ret
= tk
->tai_offset
;
1263 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1269 * __timekeeping_set_tai_offset - Lock free worker function
1272 static void __timekeeping_set_tai_offset(struct timekeeper
*tk
, s32 tai_offset
)
1274 tk
->tai_offset
= tai_offset
;
1275 tk
->offs_tai
= ktime_add(tk
->offs_real
, ktime_set(tai_offset
, 0));
1279 * timekeeping_set_tai_offset - Sets the current TAI offset from UTC
1282 void timekeeping_set_tai_offset(s32 tai_offset
)
1284 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1285 unsigned long flags
;
1287 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1288 write_seqcount_begin(&tk_core
.seq
);
1289 __timekeeping_set_tai_offset(tk
, tai_offset
);
1290 timekeeping_update(tk
, TK_MIRROR
| TK_CLOCK_WAS_SET
);
1291 write_seqcount_end(&tk_core
.seq
);
1292 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1297 * change_clocksource - Swaps clocksources if a new one is available
1299 * Accumulates current time interval and initializes new clocksource
1301 static int change_clocksource(void *data
)
1303 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1304 struct clocksource
*new, *old
;
1305 unsigned long flags
;
1307 new = (struct clocksource
*) data
;
1309 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1310 write_seqcount_begin(&tk_core
.seq
);
1312 timekeeping_forward_now(tk
);
1314 * If the cs is in module, get a module reference. Succeeds
1315 * for built-in code (owner == NULL) as well.
1317 if (try_module_get(new->owner
)) {
1318 if (!new->enable
|| new->enable(new) == 0) {
1319 old
= tk
->tkr_mono
.clock
;
1320 tk_setup_internals(tk
, new);
1323 module_put(old
->owner
);
1325 module_put(new->owner
);
1328 timekeeping_update(tk
, TK_CLEAR_NTP
| TK_MIRROR
| TK_CLOCK_WAS_SET
);
1330 write_seqcount_end(&tk_core
.seq
);
1331 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1337 * timekeeping_notify - Install a new clock source
1338 * @clock: pointer to the clock source
1340 * This function is called from clocksource.c after a new, better clock
1341 * source has been registered. The caller holds the clocksource_mutex.
1343 int timekeeping_notify(struct clocksource
*clock
)
1345 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1347 if (tk
->tkr_mono
.clock
== clock
)
1349 stop_machine(change_clocksource
, clock
, NULL
);
1350 tick_clock_notify();
1351 return tk
->tkr_mono
.clock
== clock
? 0 : -1;
1355 * getrawmonotonic64 - Returns the raw monotonic time in a timespec
1356 * @ts: pointer to the timespec64 to be set
1358 * Returns the raw monotonic time (completely un-modified by ntp)
1360 void getrawmonotonic64(struct timespec64
*ts
)
1362 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1363 struct timespec64 ts64
;
1368 seq
= read_seqcount_begin(&tk_core
.seq
);
1369 nsecs
= timekeeping_get_ns(&tk
->tkr_raw
);
1370 ts64
= tk
->raw_time
;
1372 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1374 timespec64_add_ns(&ts64
, nsecs
);
1377 EXPORT_SYMBOL(getrawmonotonic64
);
1381 * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
1383 int timekeeping_valid_for_hres(void)
1385 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1390 seq
= read_seqcount_begin(&tk_core
.seq
);
1392 ret
= tk
->tkr_mono
.clock
->flags
& CLOCK_SOURCE_VALID_FOR_HRES
;
1394 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1400 * timekeeping_max_deferment - Returns max time the clocksource can be deferred
1402 u64
timekeeping_max_deferment(void)
1404 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1409 seq
= read_seqcount_begin(&tk_core
.seq
);
1411 ret
= tk
->tkr_mono
.clock
->max_idle_ns
;
1413 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
1419 * read_persistent_clock - Return time from the persistent clock.
1421 * Weak dummy function for arches that do not yet support it.
1422 * Reads the time from the battery backed persistent clock.
1423 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
1425 * XXX - Do be sure to remove it once all arches implement it.
1427 void __weak
read_persistent_clock(struct timespec
*ts
)
1433 void __weak
read_persistent_clock64(struct timespec64
*ts64
)
1437 read_persistent_clock(&ts
);
1438 *ts64
= timespec_to_timespec64(ts
);
1442 * read_boot_clock64 - Return time of the system start.
1444 * Weak dummy function for arches that do not yet support it.
1445 * Function to read the exact time the system has been started.
1446 * Returns a timespec64 with tv_sec=0 and tv_nsec=0 if unsupported.
1448 * XXX - Do be sure to remove it once all arches implement it.
1450 void __weak
read_boot_clock64(struct timespec64
*ts
)
1456 /* Flag for if timekeeping_resume() has injected sleeptime */
1457 static bool sleeptime_injected
;
1459 /* Flag for if there is a persistent clock on this platform */
1460 static bool persistent_clock_exists
;
1463 * timekeeping_init - Initializes the clocksource and common timekeeping values
1465 void __init
timekeeping_init(void)
1467 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1468 struct clocksource
*clock
;
1469 unsigned long flags
;
1470 struct timespec64 now
, boot
, tmp
;
1472 read_persistent_clock64(&now
);
1473 if (!timespec64_valid_strict(&now
)) {
1474 pr_warn("WARNING: Persistent clock returned invalid value!\n"
1475 " Check your CMOS/BIOS settings.\n");
1478 } else if (now
.tv_sec
|| now
.tv_nsec
)
1479 persistent_clock_exists
= true;
1481 read_boot_clock64(&boot
);
1482 if (!timespec64_valid_strict(&boot
)) {
1483 pr_warn("WARNING: Boot clock returned invalid value!\n"
1484 " Check your CMOS/BIOS settings.\n");
1489 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1490 write_seqcount_begin(&tk_core
.seq
);
1493 clock
= clocksource_default_clock();
1495 clock
->enable(clock
);
1496 tk_setup_internals(tk
, clock
);
1498 tk_set_xtime(tk
, &now
);
1499 tk
->raw_time
.tv_sec
= 0;
1500 tk
->raw_time
.tv_nsec
= 0;
1501 if (boot
.tv_sec
== 0 && boot
.tv_nsec
== 0)
1502 boot
= tk_xtime(tk
);
1504 set_normalized_timespec64(&tmp
, -boot
.tv_sec
, -boot
.tv_nsec
);
1505 tk_set_wall_to_mono(tk
, tmp
);
1507 timekeeping_update(tk
, TK_MIRROR
| TK_CLOCK_WAS_SET
);
1509 write_seqcount_end(&tk_core
.seq
);
1510 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1513 /* time in seconds when suspend began for persistent clock */
1514 static struct timespec64 timekeeping_suspend_time
;
1517 * __timekeeping_inject_sleeptime - Internal function to add sleep interval
1518 * @delta: pointer to a timespec delta value
1520 * Takes a timespec offset measuring a suspend interval and properly
1521 * adds the sleep offset to the timekeeping variables.
1523 static void __timekeeping_inject_sleeptime(struct timekeeper
*tk
,
1524 struct timespec64
*delta
)
1526 if (!timespec64_valid_strict(delta
)) {
1527 printk_deferred(KERN_WARNING
1528 "__timekeeping_inject_sleeptime: Invalid "
1529 "sleep delta value!\n");
1532 tk_xtime_add(tk
, delta
);
1533 tk_set_wall_to_mono(tk
, timespec64_sub(tk
->wall_to_monotonic
, *delta
));
1534 tk_update_sleep_time(tk
, timespec64_to_ktime(*delta
));
1535 tk_debug_account_sleep_time(delta
);
1538 #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
1540 * We have three kinds of time sources to use for sleep time
1541 * injection, the preference order is:
1542 * 1) non-stop clocksource
1543 * 2) persistent clock (ie: RTC accessible when irqs are off)
1546 * 1) and 2) are used by timekeeping, 3) by RTC subsystem.
1547 * If system has neither 1) nor 2), 3) will be used finally.
1550 * If timekeeping has injected sleeptime via either 1) or 2),
1551 * 3) becomes needless, so in this case we don't need to call
1552 * rtc_resume(), and this is what timekeeping_rtc_skipresume()
1555 bool timekeeping_rtc_skipresume(void)
1557 return sleeptime_injected
;
1561 * 1) can be determined whether to use or not only when doing
1562 * timekeeping_resume() which is invoked after rtc_suspend(),
1563 * so we can't skip rtc_suspend() surely if system has 1).
1565 * But if system has 2), 2) will definitely be used, so in this
1566 * case we don't need to call rtc_suspend(), and this is what
1567 * timekeeping_rtc_skipsuspend() means.
1569 bool timekeeping_rtc_skipsuspend(void)
1571 return persistent_clock_exists
;
1575 * timekeeping_inject_sleeptime64 - Adds suspend interval to timeekeeping values
1576 * @delta: pointer to a timespec64 delta value
1578 * This hook is for architectures that cannot support read_persistent_clock64
1579 * because their RTC/persistent clock is only accessible when irqs are enabled.
1580 * and also don't have an effective nonstop clocksource.
1582 * This function should only be called by rtc_resume(), and allows
1583 * a suspend offset to be injected into the timekeeping values.
1585 void timekeeping_inject_sleeptime64(struct timespec64
*delta
)
1587 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1588 unsigned long flags
;
1590 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1591 write_seqcount_begin(&tk_core
.seq
);
1593 timekeeping_forward_now(tk
);
1595 __timekeeping_inject_sleeptime(tk
, delta
);
1597 timekeeping_update(tk
, TK_CLEAR_NTP
| TK_MIRROR
| TK_CLOCK_WAS_SET
);
1599 write_seqcount_end(&tk_core
.seq
);
1600 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1602 /* signal hrtimers about time change */
1608 * timekeeping_resume - Resumes the generic timekeeping subsystem.
1610 void timekeeping_resume(void)
1612 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1613 struct clocksource
*clock
= tk
->tkr_mono
.clock
;
1614 unsigned long flags
;
1615 struct timespec64 ts_new
, ts_delta
;
1616 cycle_t cycle_now
, cycle_delta
;
1618 sleeptime_injected
= false;
1619 read_persistent_clock64(&ts_new
);
1621 clockevents_resume();
1622 clocksource_resume();
1624 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1625 write_seqcount_begin(&tk_core
.seq
);
1628 * After system resumes, we need to calculate the suspended time and
1629 * compensate it for the OS time. There are 3 sources that could be
1630 * used: Nonstop clocksource during suspend, persistent clock and rtc
1633 * One specific platform may have 1 or 2 or all of them, and the
1634 * preference will be:
1635 * suspend-nonstop clocksource -> persistent clock -> rtc
1636 * The less preferred source will only be tried if there is no better
1637 * usable source. The rtc part is handled separately in rtc core code.
1639 cycle_now
= tk
->tkr_mono
.read(clock
);
1640 if ((clock
->flags
& CLOCK_SOURCE_SUSPEND_NONSTOP
) &&
1641 cycle_now
> tk
->tkr_mono
.cycle_last
) {
1642 u64 num
, max
= ULLONG_MAX
;
1643 u32 mult
= clock
->mult
;
1644 u32 shift
= clock
->shift
;
1647 cycle_delta
= clocksource_delta(cycle_now
, tk
->tkr_mono
.cycle_last
,
1651 * "cycle_delta * mutl" may cause 64 bits overflow, if the
1652 * suspended time is too long. In that case we need do the
1653 * 64 bits math carefully
1656 if (cycle_delta
> max
) {
1657 num
= div64_u64(cycle_delta
, max
);
1658 nsec
= (((u64
) max
* mult
) >> shift
) * num
;
1659 cycle_delta
-= num
* max
;
1661 nsec
+= ((u64
) cycle_delta
* mult
) >> shift
;
1663 ts_delta
= ns_to_timespec64(nsec
);
1664 sleeptime_injected
= true;
1665 } else if (timespec64_compare(&ts_new
, &timekeeping_suspend_time
) > 0) {
1666 ts_delta
= timespec64_sub(ts_new
, timekeeping_suspend_time
);
1667 sleeptime_injected
= true;
1670 if (sleeptime_injected
)
1671 __timekeeping_inject_sleeptime(tk
, &ts_delta
);
1673 /* Re-base the last cycle value */
1674 tk
->tkr_mono
.cycle_last
= cycle_now
;
1675 tk
->tkr_raw
.cycle_last
= cycle_now
;
1678 timekeeping_suspended
= 0;
1679 timekeeping_update(tk
, TK_MIRROR
| TK_CLOCK_WAS_SET
);
1680 write_seqcount_end(&tk_core
.seq
);
1681 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1683 touch_softlockup_watchdog();
1689 int timekeeping_suspend(void)
1691 struct timekeeper
*tk
= &tk_core
.timekeeper
;
1692 unsigned long flags
;
1693 struct timespec64 delta
, delta_delta
;
1694 static struct timespec64 old_delta
;
1696 read_persistent_clock64(&timekeeping_suspend_time
);
1699 * On some systems the persistent_clock can not be detected at
1700 * timekeeping_init by its return value, so if we see a valid
1701 * value returned, update the persistent_clock_exists flag.
1703 if (timekeeping_suspend_time
.tv_sec
|| timekeeping_suspend_time
.tv_nsec
)
1704 persistent_clock_exists
= true;
1706 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
1707 write_seqcount_begin(&tk_core
.seq
);
1708 timekeeping_forward_now(tk
);
1709 timekeeping_suspended
= 1;
1711 if (persistent_clock_exists
) {
1713 * To avoid drift caused by repeated suspend/resumes,
1714 * which each can add ~1 second drift error,
1715 * try to compensate so the difference in system time
1716 * and persistent_clock time stays close to constant.
1718 delta
= timespec64_sub(tk_xtime(tk
), timekeeping_suspend_time
);
1719 delta_delta
= timespec64_sub(delta
, old_delta
);
1720 if (abs(delta_delta
.tv_sec
) >= 2) {
1722 * if delta_delta is too large, assume time correction
1723 * has occurred and set old_delta to the current delta.
1727 /* Otherwise try to adjust old_system to compensate */
1728 timekeeping_suspend_time
=
1729 timespec64_add(timekeeping_suspend_time
, delta_delta
);
1733 timekeeping_update(tk
, TK_MIRROR
);
1734 halt_fast_timekeeper(tk
);
1735 write_seqcount_end(&tk_core
.seq
);
1736 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
1739 clocksource_suspend();
1740 clockevents_suspend();
1745 /* sysfs resume/suspend bits for timekeeping */
1746 static struct syscore_ops timekeeping_syscore_ops
= {
1747 .resume
= timekeeping_resume
,
1748 .suspend
= timekeeping_suspend
,
1751 static int __init
timekeeping_init_ops(void)
1753 register_syscore_ops(&timekeeping_syscore_ops
);
1756 device_initcall(timekeeping_init_ops
);
1759 * Apply a multiplier adjustment to the timekeeper
1761 static __always_inline
void timekeeping_apply_adjustment(struct timekeeper
*tk
,
1766 s64 interval
= tk
->cycle_interval
;
1770 mult_adj
= -mult_adj
;
1771 interval
= -interval
;
1774 mult_adj
<<= adj_scale
;
1775 interval
<<= adj_scale
;
1776 offset
<<= adj_scale
;
1779 * So the following can be confusing.
1781 * To keep things simple, lets assume mult_adj == 1 for now.
1783 * When mult_adj != 1, remember that the interval and offset values
1784 * have been appropriately scaled so the math is the same.
1786 * The basic idea here is that we're increasing the multiplier
1787 * by one, this causes the xtime_interval to be incremented by
1788 * one cycle_interval. This is because:
1789 * xtime_interval = cycle_interval * mult
1790 * So if mult is being incremented by one:
1791 * xtime_interval = cycle_interval * (mult + 1)
1793 * xtime_interval = (cycle_interval * mult) + cycle_interval
1794 * Which can be shortened to:
1795 * xtime_interval += cycle_interval
1797 * So offset stores the non-accumulated cycles. Thus the current
1798 * time (in shifted nanoseconds) is:
1799 * now = (offset * adj) + xtime_nsec
1800 * Now, even though we're adjusting the clock frequency, we have
1801 * to keep time consistent. In other words, we can't jump back
1802 * in time, and we also want to avoid jumping forward in time.
1804 * So given the same offset value, we need the time to be the same
1805 * both before and after the freq adjustment.
1806 * now = (offset * adj_1) + xtime_nsec_1
1807 * now = (offset * adj_2) + xtime_nsec_2
1809 * (offset * adj_1) + xtime_nsec_1 =
1810 * (offset * adj_2) + xtime_nsec_2
1814 * (offset * adj_1) + xtime_nsec_1 =
1815 * (offset * (adj_1+1)) + xtime_nsec_2
1816 * (offset * adj_1) + xtime_nsec_1 =
1817 * (offset * adj_1) + offset + xtime_nsec_2
1818 * Canceling the sides:
1819 * xtime_nsec_1 = offset + xtime_nsec_2
1821 * xtime_nsec_2 = xtime_nsec_1 - offset
1822 * Which simplfies to:
1823 * xtime_nsec -= offset
1825 * XXX - TODO: Doc ntp_error calculation.
1827 if ((mult_adj
> 0) && (tk
->tkr_mono
.mult
+ mult_adj
< mult_adj
)) {
1828 /* NTP adjustment caused clocksource mult overflow */
1833 tk
->tkr_mono
.mult
+= mult_adj
;
1834 tk
->xtime_interval
+= interval
;
1835 tk
->tkr_mono
.xtime_nsec
-= offset
;
1836 tk
->ntp_error
-= (interval
- offset
) << tk
->ntp_error_shift
;
1840 * Calculate the multiplier adjustment needed to match the frequency
1843 static __always_inline
void timekeeping_freqadjust(struct timekeeper
*tk
,
1846 s64 interval
= tk
->cycle_interval
;
1847 s64 xinterval
= tk
->xtime_interval
;
1848 u32 base
= tk
->tkr_mono
.clock
->mult
;
1849 u32 max
= tk
->tkr_mono
.clock
->maxadj
;
1850 u32 cur_adj
= tk
->tkr_mono
.mult
;
1855 /* Remove any current error adj from freq calculation */
1856 if (tk
->ntp_err_mult
)
1857 xinterval
-= tk
->cycle_interval
;
1859 tk
->ntp_tick
= ntp_tick_length();
1861 /* Calculate current error per tick */
1862 tick_error
= ntp_tick_length() >> tk
->ntp_error_shift
;
1863 tick_error
-= (xinterval
+ tk
->xtime_remainder
);
1865 /* Don't worry about correcting it if its small */
1866 if (likely((tick_error
>= 0) && (tick_error
<= interval
)))
1869 /* preserve the direction of correction */
1870 negative
= (tick_error
< 0);
1872 /* If any adjustment would pass the max, just return */
1873 if (negative
&& (cur_adj
- 1) <= (base
- max
))
1875 if (!negative
&& (cur_adj
+ 1) >= (base
+ max
))
1878 * Sort out the magnitude of the correction, but
1879 * avoid making so large a correction that we go
1880 * over the max adjustment.
1883 tick_error
= abs(tick_error
);
1884 while (tick_error
> interval
) {
1885 u32 adj
= 1 << (adj_scale
+ 1);
1887 /* Check if adjustment gets us within 1 unit from the max */
1888 if (negative
&& (cur_adj
- adj
) <= (base
- max
))
1890 if (!negative
&& (cur_adj
+ adj
) >= (base
+ max
))
1897 /* scale the corrections */
1898 timekeeping_apply_adjustment(tk
, offset
, negative
, adj_scale
);
1902 * Adjust the timekeeper's multiplier to the correct frequency
1903 * and also to reduce the accumulated error value.
1905 static void timekeeping_adjust(struct timekeeper
*tk
, s64 offset
)
1907 /* Correct for the current frequency error */
1908 timekeeping_freqadjust(tk
, offset
);
1910 /* Next make a small adjustment to fix any cumulative error */
1911 if (!tk
->ntp_err_mult
&& (tk
->ntp_error
> 0)) {
1912 tk
->ntp_err_mult
= 1;
1913 timekeeping_apply_adjustment(tk
, offset
, 0, 0);
1914 } else if (tk
->ntp_err_mult
&& (tk
->ntp_error
<= 0)) {
1915 /* Undo any existing error adjustment */
1916 timekeeping_apply_adjustment(tk
, offset
, 1, 0);
1917 tk
->ntp_err_mult
= 0;
1920 if (unlikely(tk
->tkr_mono
.clock
->maxadj
&&
1921 (abs(tk
->tkr_mono
.mult
- tk
->tkr_mono
.clock
->mult
)
1922 > tk
->tkr_mono
.clock
->maxadj
))) {
1923 printk_once(KERN_WARNING
1924 "Adjusting %s more than 11%% (%ld vs %ld)\n",
1925 tk
->tkr_mono
.clock
->name
, (long)tk
->tkr_mono
.mult
,
1926 (long)tk
->tkr_mono
.clock
->mult
+ tk
->tkr_mono
.clock
->maxadj
);
1930 * It may be possible that when we entered this function, xtime_nsec
1931 * was very small. Further, if we're slightly speeding the clocksource
1932 * in the code above, its possible the required corrective factor to
1933 * xtime_nsec could cause it to underflow.
1935 * Now, since we already accumulated the second, cannot simply roll
1936 * the accumulated second back, since the NTP subsystem has been
1937 * notified via second_overflow. So instead we push xtime_nsec forward
1938 * by the amount we underflowed, and add that amount into the error.
1940 * We'll correct this error next time through this function, when
1941 * xtime_nsec is not as small.
1943 if (unlikely((s64
)tk
->tkr_mono
.xtime_nsec
< 0)) {
1944 s64 neg
= -(s64
)tk
->tkr_mono
.xtime_nsec
;
1945 tk
->tkr_mono
.xtime_nsec
= 0;
1946 tk
->ntp_error
+= neg
<< tk
->ntp_error_shift
;
1951 * accumulate_nsecs_to_secs - Accumulates nsecs into secs
1953 * Helper function that accumulates the nsecs greater than a second
1954 * from the xtime_nsec field to the xtime_secs field.
1955 * It also calls into the NTP code to handle leapsecond processing.
1958 static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper
*tk
)
1960 u64 nsecps
= (u64
)NSEC_PER_SEC
<< tk
->tkr_mono
.shift
;
1961 unsigned int clock_set
= 0;
1963 while (tk
->tkr_mono
.xtime_nsec
>= nsecps
) {
1966 tk
->tkr_mono
.xtime_nsec
-= nsecps
;
1969 /* Figure out if its a leap sec and apply if needed */
1970 leap
= second_overflow(tk
->xtime_sec
);
1971 if (unlikely(leap
)) {
1972 struct timespec64 ts
;
1974 tk
->xtime_sec
+= leap
;
1978 tk_set_wall_to_mono(tk
,
1979 timespec64_sub(tk
->wall_to_monotonic
, ts
));
1981 __timekeeping_set_tai_offset(tk
, tk
->tai_offset
- leap
);
1983 clock_set
= TK_CLOCK_WAS_SET
;
1990 * logarithmic_accumulation - shifted accumulation of cycles
1992 * This functions accumulates a shifted interval of cycles into
1993 * into a shifted interval nanoseconds. Allows for O(log) accumulation
1996 * Returns the unconsumed cycles.
1998 static cycle_t
logarithmic_accumulation(struct timekeeper
*tk
, cycle_t offset
,
2000 unsigned int *clock_set
)
2002 cycle_t interval
= tk
->cycle_interval
<< shift
;
2005 /* If the offset is smaller than a shifted interval, do nothing */
2006 if (offset
< interval
)
2009 /* Accumulate one shifted interval */
2011 tk
->tkr_mono
.cycle_last
+= interval
;
2012 tk
->tkr_raw
.cycle_last
+= interval
;
2014 tk
->tkr_mono
.xtime_nsec
+= tk
->xtime_interval
<< shift
;
2015 *clock_set
|= accumulate_nsecs_to_secs(tk
);
2017 /* Accumulate raw time */
2018 raw_nsecs
= (u64
)tk
->raw_interval
<< shift
;
2019 raw_nsecs
+= tk
->raw_time
.tv_nsec
;
2020 if (raw_nsecs
>= NSEC_PER_SEC
) {
2021 u64 raw_secs
= raw_nsecs
;
2022 raw_nsecs
= do_div(raw_secs
, NSEC_PER_SEC
);
2023 tk
->raw_time
.tv_sec
+= raw_secs
;
2025 tk
->raw_time
.tv_nsec
= raw_nsecs
;
2027 /* Accumulate error between NTP and clock interval */
2028 tk
->ntp_error
+= tk
->ntp_tick
<< shift
;
2029 tk
->ntp_error
-= (tk
->xtime_interval
+ tk
->xtime_remainder
) <<
2030 (tk
->ntp_error_shift
+ shift
);
2036 * update_wall_time - Uses the current clocksource to increment the wall time
2039 void update_wall_time(void)
2041 struct timekeeper
*real_tk
= &tk_core
.timekeeper
;
2042 struct timekeeper
*tk
= &shadow_timekeeper
;
2044 int shift
= 0, maxshift
;
2045 unsigned int clock_set
= 0;
2046 unsigned long flags
;
2048 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
2050 /* Make sure we're fully resumed: */
2051 if (unlikely(timekeeping_suspended
))
2054 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
2055 offset
= real_tk
->cycle_interval
;
2057 offset
= clocksource_delta(tk
->tkr_mono
.read(tk
->tkr_mono
.clock
),
2058 tk
->tkr_mono
.cycle_last
, tk
->tkr_mono
.mask
);
2061 /* Check if there's really nothing to do */
2062 if (offset
< real_tk
->cycle_interval
)
2065 /* Do some additional sanity checking */
2066 timekeeping_check_update(real_tk
, offset
);
2069 * With NO_HZ we may have to accumulate many cycle_intervals
2070 * (think "ticks") worth of time at once. To do this efficiently,
2071 * we calculate the largest doubling multiple of cycle_intervals
2072 * that is smaller than the offset. We then accumulate that
2073 * chunk in one go, and then try to consume the next smaller
2076 shift
= ilog2(offset
) - ilog2(tk
->cycle_interval
);
2077 shift
= max(0, shift
);
2078 /* Bound shift to one less than what overflows tick_length */
2079 maxshift
= (64 - (ilog2(ntp_tick_length())+1)) - 1;
2080 shift
= min(shift
, maxshift
);
2081 while (offset
>= tk
->cycle_interval
) {
2082 offset
= logarithmic_accumulation(tk
, offset
, shift
,
2084 if (offset
< tk
->cycle_interval
<<shift
)
2088 /* correct the clock when NTP error is too big */
2089 timekeeping_adjust(tk
, offset
);
2092 * XXX This can be killed once everyone converts
2093 * to the new update_vsyscall.
2095 old_vsyscall_fixup(tk
);
2098 * Finally, make sure that after the rounding
2099 * xtime_nsec isn't larger than NSEC_PER_SEC
2101 clock_set
|= accumulate_nsecs_to_secs(tk
);
2103 write_seqcount_begin(&tk_core
.seq
);
2105 * Update the real timekeeper.
2107 * We could avoid this memcpy by switching pointers, but that
2108 * requires changes to all other timekeeper usage sites as
2109 * well, i.e. move the timekeeper pointer getter into the
2110 * spinlocked/seqcount protected sections. And we trade this
2111 * memcpy under the tk_core.seq against one before we start
2114 timekeeping_update(tk
, clock_set
);
2115 memcpy(real_tk
, tk
, sizeof(*tk
));
2116 /* The memcpy must come last. Do not put anything here! */
2117 write_seqcount_end(&tk_core
.seq
);
2119 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
2121 /* Have to call _delayed version, since in irq context*/
2122 clock_was_set_delayed();
2126 * getboottime64 - Return the real time of system boot.
2127 * @ts: pointer to the timespec64 to be set
2129 * Returns the wall-time of boot in a timespec64.
2131 * This is based on the wall_to_monotonic offset and the total suspend
2132 * time. Calls to settimeofday will affect the value returned (which
2133 * basically means that however wrong your real time clock is at boot time,
2134 * you get the right time here).
2136 void getboottime64(struct timespec64
*ts
)
2138 struct timekeeper
*tk
= &tk_core
.timekeeper
;
2139 ktime_t t
= ktime_sub(tk
->offs_real
, tk
->offs_boot
);
2141 *ts
= ktime_to_timespec64(t
);
2143 EXPORT_SYMBOL_GPL(getboottime64
);
2145 unsigned long get_seconds(void)
2147 struct timekeeper
*tk
= &tk_core
.timekeeper
;
2149 return tk
->xtime_sec
;
2151 EXPORT_SYMBOL(get_seconds
);
2153 struct timespec
__current_kernel_time(void)
2155 struct timekeeper
*tk
= &tk_core
.timekeeper
;
2157 return timespec64_to_timespec(tk_xtime(tk
));
2160 struct timespec64
current_kernel_time64(void)
2162 struct timekeeper
*tk
= &tk_core
.timekeeper
;
2163 struct timespec64 now
;
2167 seq
= read_seqcount_begin(&tk_core
.seq
);
2170 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
2174 EXPORT_SYMBOL(current_kernel_time64
);
2176 struct timespec64
get_monotonic_coarse64(void)
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(&now
, now
.tv_sec
+ mono
.tv_sec
,
2190 now
.tv_nsec
+ mono
.tv_nsec
);
2194 EXPORT_SYMBOL(get_monotonic_coarse64
);
2197 * Must hold jiffies_lock
2199 void do_timer(unsigned long ticks
)
2201 jiffies_64
+= ticks
;
2202 calc_global_load(ticks
);
2206 * ktime_get_update_offsets_now - hrtimer helper
2207 * @cwsseq: pointer to check and store the clock was set sequence number
2208 * @offs_real: pointer to storage for monotonic -> realtime offset
2209 * @offs_boot: pointer to storage for monotonic -> boottime offset
2210 * @offs_tai: pointer to storage for monotonic -> clock tai offset
2212 * Returns current monotonic time and updates the offsets if the
2213 * sequence number in @cwsseq and timekeeper.clock_was_set_seq are
2216 * Called from hrtimer_interrupt() or retrigger_next_event()
2218 ktime_t
ktime_get_update_offsets_now(unsigned int *cwsseq
, ktime_t
*offs_real
,
2219 ktime_t
*offs_boot
, ktime_t
*offs_tai
)
2221 struct timekeeper
*tk
= &tk_core
.timekeeper
;
2227 seq
= read_seqcount_begin(&tk_core
.seq
);
2229 base
= tk
->tkr_mono
.base
;
2230 nsecs
= timekeeping_get_ns(&tk
->tkr_mono
);
2231 base
= ktime_add_ns(base
, nsecs
);
2233 if (*cwsseq
!= tk
->clock_was_set_seq
) {
2234 *cwsseq
= tk
->clock_was_set_seq
;
2235 *offs_real
= tk
->offs_real
;
2236 *offs_boot
= tk
->offs_boot
;
2237 *offs_tai
= tk
->offs_tai
;
2240 /* Handle leapsecond insertion adjustments */
2241 if (unlikely(base
.tv64
>= tk
->next_leap_ktime
.tv64
))
2242 *offs_real
= ktime_sub(tk
->offs_real
, ktime_set(1, 0));
2244 } while (read_seqcount_retry(&tk_core
.seq
, seq
));
2250 * do_adjtimex() - Accessor function to NTP __do_adjtimex function
2252 int do_adjtimex(struct timex
*txc
)
2254 struct timekeeper
*tk
= &tk_core
.timekeeper
;
2255 unsigned long flags
;
2256 struct timespec64 ts
;
2260 /* Validate the data before disabling interrupts */
2261 ret
= ntp_validate_timex(txc
);
2265 if (txc
->modes
& ADJ_SETOFFSET
) {
2266 struct timespec delta
;
2267 delta
.tv_sec
= txc
->time
.tv_sec
;
2268 delta
.tv_nsec
= txc
->time
.tv_usec
;
2269 if (!(txc
->modes
& ADJ_NANO
))
2270 delta
.tv_nsec
*= 1000;
2271 ret
= timekeeping_inject_offset(&delta
);
2276 getnstimeofday64(&ts
);
2278 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
2279 write_seqcount_begin(&tk_core
.seq
);
2281 orig_tai
= tai
= tk
->tai_offset
;
2282 ret
= __do_adjtimex(txc
, &ts
, &tai
);
2284 if (tai
!= orig_tai
) {
2285 __timekeeping_set_tai_offset(tk
, tai
);
2286 timekeeping_update(tk
, TK_MIRROR
| TK_CLOCK_WAS_SET
);
2288 tk_update_leap_state(tk
);
2290 write_seqcount_end(&tk_core
.seq
);
2291 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
2293 if (tai
!= orig_tai
)
2296 ntp_notify_cmos_timer();
2301 #ifdef CONFIG_NTP_PPS
2303 * hardpps() - Accessor function to NTP __hardpps function
2305 void hardpps(const struct timespec64
*phase_ts
, const struct timespec64
*raw_ts
)
2307 unsigned long flags
;
2309 raw_spin_lock_irqsave(&timekeeper_lock
, flags
);
2310 write_seqcount_begin(&tk_core
.seq
);
2312 __hardpps(phase_ts
, raw_ts
);
2314 write_seqcount_end(&tk_core
.seq
);
2315 raw_spin_unlock_irqrestore(&timekeeper_lock
, flags
);
2317 EXPORT_SYMBOL(hardpps
);
2321 * xtime_update() - advances the timekeeping infrastructure
2322 * @ticks: number of ticks, that have elapsed since the last call.
2324 * Must be called with interrupts disabled.
2326 void xtime_update(unsigned long ticks
)
2328 write_seqlock(&jiffies_lock
);
2330 write_sequnlock(&jiffies_lock
);