85d3763963135cbbdc194fea894452b7f74c0c9b
[deliverable/linux.git] / kernel / time / timekeeping.c
1 /*
2 * linux/kernel/time/timekeeping.c
3 *
4 * Kernel timekeeping code and accessor functions
5 *
6 * This code was moved from linux/kernel/timer.c.
7 * Please see that file for copyright and history logs.
8 *
9 */
10
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>
16 #include <linux/mm.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>
26
27 #include "tick-internal.h"
28 #include "ntp_internal.h"
29 #include "timekeeping_internal.h"
30
31 #define TK_CLEAR_NTP (1 << 0)
32 #define TK_MIRROR (1 << 1)
33 #define TK_CLOCK_WAS_SET (1 << 2)
34
35 /*
36 * The most important data for readout fits into a single 64 byte
37 * cache line.
38 */
39 static struct {
40 seqcount_t seq;
41 struct timekeeper timekeeper;
42 } tk_core ____cacheline_aligned;
43
44 static DEFINE_RAW_SPINLOCK(timekeeper_lock);
45 static struct timekeeper shadow_timekeeper;
46
47 /**
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
52 * @seq.
53 *
54 * See @update_fast_timekeeper() below.
55 */
56 struct tk_fast {
57 seqcount_t seq;
58 struct tk_read_base base[2];
59 };
60
61 static struct tk_fast tk_fast_mono ____cacheline_aligned;
62 static struct tk_fast tk_fast_raw ____cacheline_aligned;
63
64 /* flag for if timekeeping is suspended */
65 int __read_mostly timekeeping_suspended;
66
67 static inline void tk_normalize_xtime(struct timekeeper *tk)
68 {
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;
71 tk->xtime_sec++;
72 }
73 }
74
75 static inline struct timespec64 tk_xtime(struct timekeeper *tk)
76 {
77 struct timespec64 ts;
78
79 ts.tv_sec = tk->xtime_sec;
80 ts.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
81 return ts;
82 }
83
84 static void tk_set_xtime(struct timekeeper *tk, const struct timespec64 *ts)
85 {
86 tk->xtime_sec = ts->tv_sec;
87 tk->tkr_mono.xtime_nsec = (u64)ts->tv_nsec << tk->tkr_mono.shift;
88 }
89
90 static void tk_xtime_add(struct timekeeper *tk, const struct timespec64 *ts)
91 {
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);
95 }
96
97 static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec64 wtm)
98 {
99 struct timespec64 tmp;
100
101 /*
102 * Verify consistency of: offset_real = -wall_to_monotonic
103 * before modifying anything
104 */
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));
112 }
113
114 static inline void tk_update_sleep_time(struct timekeeper *tk, ktime_t delta)
115 {
116 tk->offs_boot = ktime_add(tk->offs_boot, delta);
117 }
118
119 #ifdef CONFIG_DEBUG_TIMEKEEPING
120 #define WARNING_FREQ (HZ*300) /* 5 minute rate-limiting */
121 /*
122 * These simple flag variables are managed
123 * without locks, which is racy, but ok since
124 * we don't really care about being super
125 * precise about how many events were seen,
126 * just that a problem was observed.
127 */
128 static int timekeeping_underflow_seen;
129 static int timekeeping_overflow_seen;
130
131 /* last_warning is only modified under the timekeeping lock */
132 static long timekeeping_last_warning;
133
134 static void timekeeping_check_update(struct timekeeper *tk, cycle_t offset)
135 {
136
137 cycle_t max_cycles = tk->tkr_mono.clock->max_cycles;
138 const char *name = tk->tkr_mono.clock->name;
139
140 if (offset > max_cycles) {
141 printk_deferred("WARNING: timekeeping: Cycle offset (%lld) is larger than allowed by the '%s' clock's max_cycles value (%lld): time overflow danger\n",
142 offset, name, max_cycles);
143 printk_deferred(" timekeeping: Your kernel is sick, but tries to cope by capping time updates\n");
144 } else {
145 if (offset > (max_cycles >> 1)) {
146 printk_deferred("INFO: timekeeping: Cycle offset (%lld) is larger than the the '%s' clock's 50%% safety margin (%lld)\n",
147 offset, name, max_cycles >> 1);
148 printk_deferred(" timekeeping: Your kernel is still fine, but is feeling a bit nervous\n");
149 }
150 }
151
152 if (timekeeping_underflow_seen) {
153 if (jiffies - timekeeping_last_warning > WARNING_FREQ) {
154 printk_deferred("WARNING: Underflow in clocksource '%s' observed, time update ignored.\n", name);
155 printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
156 printk_deferred(" Your kernel is probably still fine.\n");
157 timekeeping_last_warning = jiffies;
158 }
159 timekeeping_underflow_seen = 0;
160 }
161
162 if (timekeeping_overflow_seen) {
163 if (jiffies - timekeeping_last_warning > WARNING_FREQ) {
164 printk_deferred("WARNING: Overflow in clocksource '%s' observed, time update capped.\n", name);
165 printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
166 printk_deferred(" Your kernel is probably still fine.\n");
167 timekeeping_last_warning = jiffies;
168 }
169 timekeeping_overflow_seen = 0;
170 }
171 }
172
173 static inline cycle_t timekeeping_get_delta(struct tk_read_base *tkr)
174 {
175 cycle_t now, last, mask, max, delta;
176 unsigned int seq;
177
178 /*
179 * Since we're called holding a seqlock, the data may shift
180 * under us while we're doing the calculation. This can cause
181 * false positives, since we'd note a problem but throw the
182 * results away. So nest another seqlock here to atomically
183 * grab the points we are checking with.
184 */
185 do {
186 seq = read_seqcount_begin(&tk_core.seq);
187 now = tkr->read(tkr->clock);
188 last = tkr->cycle_last;
189 mask = tkr->mask;
190 max = tkr->clock->max_cycles;
191 } while (read_seqcount_retry(&tk_core.seq, seq));
192
193 delta = clocksource_delta(now, last, mask);
194
195 /*
196 * Try to catch underflows by checking if we are seeing small
197 * mask-relative negative values.
198 */
199 if (unlikely((~delta & mask) < (mask >> 3))) {
200 timekeeping_underflow_seen = 1;
201 delta = 0;
202 }
203
204 /* Cap delta value to the max_cycles values to avoid mult overflows */
205 if (unlikely(delta > max)) {
206 timekeeping_overflow_seen = 1;
207 delta = tkr->clock->max_cycles;
208 }
209
210 return delta;
211 }
212 #else
213 static inline void timekeeping_check_update(struct timekeeper *tk, cycle_t offset)
214 {
215 }
216 static inline cycle_t timekeeping_get_delta(struct tk_read_base *tkr)
217 {
218 cycle_t cycle_now, delta;
219
220 /* read clocksource */
221 cycle_now = tkr->read(tkr->clock);
222
223 /* calculate the delta since the last update_wall_time */
224 delta = clocksource_delta(cycle_now, tkr->cycle_last, tkr->mask);
225
226 return delta;
227 }
228 #endif
229
230 /**
231 * tk_setup_internals - Set up internals to use clocksource clock.
232 *
233 * @tk: The target timekeeper to setup.
234 * @clock: Pointer to clocksource.
235 *
236 * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
237 * pair and interval request.
238 *
239 * Unless you're the timekeeping code, you should not be using this!
240 */
241 static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock)
242 {
243 cycle_t interval;
244 u64 tmp, ntpinterval;
245 struct clocksource *old_clock;
246
247 old_clock = tk->tkr_mono.clock;
248 tk->tkr_mono.clock = clock;
249 tk->tkr_mono.read = clock->read;
250 tk->tkr_mono.mask = clock->mask;
251 tk->tkr_mono.cycle_last = tk->tkr_mono.read(clock);
252
253 tk->tkr_raw.clock = clock;
254 tk->tkr_raw.read = clock->read;
255 tk->tkr_raw.mask = clock->mask;
256 tk->tkr_raw.cycle_last = tk->tkr_mono.cycle_last;
257
258 /* Do the ns -> cycle conversion first, using original mult */
259 tmp = NTP_INTERVAL_LENGTH;
260 tmp <<= clock->shift;
261 ntpinterval = tmp;
262 tmp += clock->mult/2;
263 do_div(tmp, clock->mult);
264 if (tmp == 0)
265 tmp = 1;
266
267 interval = (cycle_t) tmp;
268 tk->cycle_interval = interval;
269
270 /* Go back from cycles -> shifted ns */
271 tk->xtime_interval = (u64) interval * clock->mult;
272 tk->xtime_remainder = ntpinterval - tk->xtime_interval;
273 tk->raw_interval =
274 ((u64) interval * clock->mult) >> clock->shift;
275
276 /* if changing clocks, convert xtime_nsec shift units */
277 if (old_clock) {
278 int shift_change = clock->shift - old_clock->shift;
279 if (shift_change < 0)
280 tk->tkr_mono.xtime_nsec >>= -shift_change;
281 else
282 tk->tkr_mono.xtime_nsec <<= shift_change;
283 }
284 tk->tkr_raw.xtime_nsec = 0;
285
286 tk->tkr_mono.shift = clock->shift;
287 tk->tkr_raw.shift = clock->shift;
288
289 tk->ntp_error = 0;
290 tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
291 tk->ntp_tick = ntpinterval << tk->ntp_error_shift;
292
293 /*
294 * The timekeeper keeps its own mult values for the currently
295 * active clocksource. These value will be adjusted via NTP
296 * to counteract clock drifting.
297 */
298 tk->tkr_mono.mult = clock->mult;
299 tk->tkr_raw.mult = clock->mult;
300 tk->ntp_err_mult = 0;
301 }
302
303 /* Timekeeper helper functions. */
304
305 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
306 static u32 default_arch_gettimeoffset(void) { return 0; }
307 u32 (*arch_gettimeoffset)(void) = default_arch_gettimeoffset;
308 #else
309 static inline u32 arch_gettimeoffset(void) { return 0; }
310 #endif
311
312 static inline s64 timekeeping_get_ns(struct tk_read_base *tkr)
313 {
314 cycle_t delta;
315 s64 nsec;
316
317 delta = timekeeping_get_delta(tkr);
318
319 nsec = delta * tkr->mult + tkr->xtime_nsec;
320 nsec >>= tkr->shift;
321
322 /* If arch requires, add in get_arch_timeoffset() */
323 return nsec + arch_gettimeoffset();
324 }
325
326 /**
327 * update_fast_timekeeper - Update the fast and NMI safe monotonic timekeeper.
328 * @tkr: Timekeeping readout base from which we take the update
329 *
330 * We want to use this from any context including NMI and tracing /
331 * instrumenting the timekeeping code itself.
332 *
333 * So we handle this differently than the other timekeeping accessor
334 * functions which retry when the sequence count has changed. The
335 * update side does:
336 *
337 * smp_wmb(); <- Ensure that the last base[1] update is visible
338 * tkf->seq++;
339 * smp_wmb(); <- Ensure that the seqcount update is visible
340 * update(tkf->base[0], tkr);
341 * smp_wmb(); <- Ensure that the base[0] update is visible
342 * tkf->seq++;
343 * smp_wmb(); <- Ensure that the seqcount update is visible
344 * update(tkf->base[1], tkr);
345 *
346 * The reader side does:
347 *
348 * do {
349 * seq = tkf->seq;
350 * smp_rmb();
351 * idx = seq & 0x01;
352 * now = now(tkf->base[idx]);
353 * smp_rmb();
354 * } while (seq != tkf->seq)
355 *
356 * As long as we update base[0] readers are forced off to
357 * base[1]. Once base[0] is updated readers are redirected to base[0]
358 * and the base[1] update takes place.
359 *
360 * So if a NMI hits the update of base[0] then it will use base[1]
361 * which is still consistent. In the worst case this can result is a
362 * slightly wrong timestamp (a few nanoseconds). See
363 * @ktime_get_mono_fast_ns.
364 */
365 static void update_fast_timekeeper(struct tk_read_base *tkr, struct tk_fast *tkf)
366 {
367 struct tk_read_base *base = tkf->base;
368
369 /* Force readers off to base[1] */
370 raw_write_seqcount_latch(&tkf->seq);
371
372 /* Update base[0] */
373 memcpy(base, tkr, sizeof(*base));
374
375 /* Force readers back to base[0] */
376 raw_write_seqcount_latch(&tkf->seq);
377
378 /* Update base[1] */
379 memcpy(base + 1, base, sizeof(*base));
380 }
381
382 /**
383 * ktime_get_mono_fast_ns - Fast NMI safe access to clock monotonic
384 *
385 * This timestamp is not guaranteed to be monotonic across an update.
386 * The timestamp is calculated by:
387 *
388 * now = base_mono + clock_delta * slope
389 *
390 * So if the update lowers the slope, readers who are forced to the
391 * not yet updated second array are still using the old steeper slope.
392 *
393 * tmono
394 * ^
395 * | o n
396 * | o n
397 * | u
398 * | o
399 * |o
400 * |12345678---> reader order
401 *
402 * o = old slope
403 * u = update
404 * n = new slope
405 *
406 * So reader 6 will observe time going backwards versus reader 5.
407 *
408 * While other CPUs are likely to be able observe that, the only way
409 * for a CPU local observation is when an NMI hits in the middle of
410 * the update. Timestamps taken from that NMI context might be ahead
411 * of the following timestamps. Callers need to be aware of that and
412 * deal with it.
413 */
414 static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf)
415 {
416 struct tk_read_base *tkr;
417 unsigned int seq;
418 u64 now;
419
420 do {
421 seq = raw_read_seqcount(&tkf->seq);
422 tkr = tkf->base + (seq & 0x01);
423 now = ktime_to_ns(tkr->base) + timekeeping_get_ns(tkr);
424 } while (read_seqcount_retry(&tkf->seq, seq));
425
426 return now;
427 }
428
429 u64 ktime_get_mono_fast_ns(void)
430 {
431 return __ktime_get_fast_ns(&tk_fast_mono);
432 }
433 EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns);
434
435 u64 ktime_get_raw_fast_ns(void)
436 {
437 return __ktime_get_fast_ns(&tk_fast_raw);
438 }
439 EXPORT_SYMBOL_GPL(ktime_get_raw_fast_ns);
440
441 /* Suspend-time cycles value for halted fast timekeeper. */
442 static cycle_t cycles_at_suspend;
443
444 static cycle_t dummy_clock_read(struct clocksource *cs)
445 {
446 return cycles_at_suspend;
447 }
448
449 /**
450 * halt_fast_timekeeper - Prevent fast timekeeper from accessing clocksource.
451 * @tk: Timekeeper to snapshot.
452 *
453 * It generally is unsafe to access the clocksource after timekeeping has been
454 * suspended, so take a snapshot of the readout base of @tk and use it as the
455 * fast timekeeper's readout base while suspended. It will return the same
456 * number of cycles every time until timekeeping is resumed at which time the
457 * proper readout base for the fast timekeeper will be restored automatically.
458 */
459 static void halt_fast_timekeeper(struct timekeeper *tk)
460 {
461 static struct tk_read_base tkr_dummy;
462 struct tk_read_base *tkr = &tk->tkr_mono;
463
464 memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
465 cycles_at_suspend = tkr->read(tkr->clock);
466 tkr_dummy.read = dummy_clock_read;
467 update_fast_timekeeper(&tkr_dummy, &tk_fast_mono);
468
469 tkr = &tk->tkr_raw;
470 memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
471 tkr_dummy.read = dummy_clock_read;
472 update_fast_timekeeper(&tkr_dummy, &tk_fast_raw);
473 }
474
475 #ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD
476
477 static inline void update_vsyscall(struct timekeeper *tk)
478 {
479 struct timespec xt, wm;
480
481 xt = timespec64_to_timespec(tk_xtime(tk));
482 wm = timespec64_to_timespec(tk->wall_to_monotonic);
483 update_vsyscall_old(&xt, &wm, tk->tkr_mono.clock, tk->tkr_mono.mult,
484 tk->tkr_mono.cycle_last);
485 }
486
487 static inline void old_vsyscall_fixup(struct timekeeper *tk)
488 {
489 s64 remainder;
490
491 /*
492 * Store only full nanoseconds into xtime_nsec after rounding
493 * it up and add the remainder to the error difference.
494 * XXX - This is necessary to avoid small 1ns inconsistnecies caused
495 * by truncating the remainder in vsyscalls. However, it causes
496 * additional work to be done in timekeeping_adjust(). Once
497 * the vsyscall implementations are converted to use xtime_nsec
498 * (shifted nanoseconds), and CONFIG_GENERIC_TIME_VSYSCALL_OLD
499 * users are removed, this can be killed.
500 */
501 remainder = tk->tkr_mono.xtime_nsec & ((1ULL << tk->tkr_mono.shift) - 1);
502 tk->tkr_mono.xtime_nsec -= remainder;
503 tk->tkr_mono.xtime_nsec += 1ULL << tk->tkr_mono.shift;
504 tk->ntp_error += remainder << tk->ntp_error_shift;
505 tk->ntp_error -= (1ULL << tk->tkr_mono.shift) << tk->ntp_error_shift;
506 }
507 #else
508 #define old_vsyscall_fixup(tk)
509 #endif
510
511 static RAW_NOTIFIER_HEAD(pvclock_gtod_chain);
512
513 static void update_pvclock_gtod(struct timekeeper *tk, bool was_set)
514 {
515 raw_notifier_call_chain(&pvclock_gtod_chain, was_set, tk);
516 }
517
518 /**
519 * pvclock_gtod_register_notifier - register a pvclock timedata update listener
520 */
521 int pvclock_gtod_register_notifier(struct notifier_block *nb)
522 {
523 struct timekeeper *tk = &tk_core.timekeeper;
524 unsigned long flags;
525 int ret;
526
527 raw_spin_lock_irqsave(&timekeeper_lock, flags);
528 ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb);
529 update_pvclock_gtod(tk, true);
530 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
531
532 return ret;
533 }
534 EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier);
535
536 /**
537 * pvclock_gtod_unregister_notifier - unregister a pvclock
538 * timedata update listener
539 */
540 int pvclock_gtod_unregister_notifier(struct notifier_block *nb)
541 {
542 unsigned long flags;
543 int ret;
544
545 raw_spin_lock_irqsave(&timekeeper_lock, flags);
546 ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb);
547 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
548
549 return ret;
550 }
551 EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier);
552
553 /*
554 * Update the ktime_t based scalar nsec members of the timekeeper
555 */
556 static inline void tk_update_ktime_data(struct timekeeper *tk)
557 {
558 u64 seconds;
559 u32 nsec;
560
561 /*
562 * The xtime based monotonic readout is:
563 * nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();
564 * The ktime based monotonic readout is:
565 * nsec = base_mono + now();
566 * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec
567 */
568 seconds = (u64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec);
569 nsec = (u32) tk->wall_to_monotonic.tv_nsec;
570 tk->tkr_mono.base = ns_to_ktime(seconds * NSEC_PER_SEC + nsec);
571
572 /* Update the monotonic raw base */
573 tk->tkr_raw.base = timespec64_to_ktime(tk->raw_time);
574
575 /*
576 * The sum of the nanoseconds portions of xtime and
577 * wall_to_monotonic can be greater/equal one second. Take
578 * this into account before updating tk->ktime_sec.
579 */
580 nsec += (u32)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
581 if (nsec >= NSEC_PER_SEC)
582 seconds++;
583 tk->ktime_sec = seconds;
584 }
585
586 /* must hold timekeeper_lock */
587 static void timekeeping_update(struct timekeeper *tk, unsigned int action)
588 {
589 if (action & TK_CLEAR_NTP) {
590 tk->ntp_error = 0;
591 ntp_clear();
592 }
593
594 tk_update_ktime_data(tk);
595
596 update_vsyscall(tk);
597 update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);
598
599 if (action & TK_MIRROR)
600 memcpy(&shadow_timekeeper, &tk_core.timekeeper,
601 sizeof(tk_core.timekeeper));
602
603 update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
604 update_fast_timekeeper(&tk->tkr_raw, &tk_fast_raw);
605
606 if (action & TK_CLOCK_WAS_SET)
607 tk->clock_was_set_seq++;
608 }
609
610 /**
611 * timekeeping_forward_now - update clock to the current time
612 *
613 * Forward the current clock to update its state since the last call to
614 * update_wall_time(). This is useful before significant clock changes,
615 * as it avoids having to deal with this time offset explicitly.
616 */
617 static void timekeeping_forward_now(struct timekeeper *tk)
618 {
619 struct clocksource *clock = tk->tkr_mono.clock;
620 cycle_t cycle_now, delta;
621 s64 nsec;
622
623 cycle_now = tk->tkr_mono.read(clock);
624 delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
625 tk->tkr_mono.cycle_last = cycle_now;
626 tk->tkr_raw.cycle_last = cycle_now;
627
628 tk->tkr_mono.xtime_nsec += delta * tk->tkr_mono.mult;
629
630 /* If arch requires, add in get_arch_timeoffset() */
631 tk->tkr_mono.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr_mono.shift;
632
633 tk_normalize_xtime(tk);
634
635 nsec = clocksource_cyc2ns(delta, tk->tkr_raw.mult, tk->tkr_raw.shift);
636 timespec64_add_ns(&tk->raw_time, nsec);
637 }
638
639 /**
640 * __getnstimeofday64 - Returns the time of day in a timespec64.
641 * @ts: pointer to the timespec to be set
642 *
643 * Updates the time of day in the timespec.
644 * Returns 0 on success, or -ve when suspended (timespec will be undefined).
645 */
646 int __getnstimeofday64(struct timespec64 *ts)
647 {
648 struct timekeeper *tk = &tk_core.timekeeper;
649 unsigned long seq;
650 s64 nsecs = 0;
651
652 do {
653 seq = read_seqcount_begin(&tk_core.seq);
654
655 ts->tv_sec = tk->xtime_sec;
656 nsecs = timekeeping_get_ns(&tk->tkr_mono);
657
658 } while (read_seqcount_retry(&tk_core.seq, seq));
659
660 ts->tv_nsec = 0;
661 timespec64_add_ns(ts, nsecs);
662
663 /*
664 * Do not bail out early, in case there were callers still using
665 * the value, even in the face of the WARN_ON.
666 */
667 if (unlikely(timekeeping_suspended))
668 return -EAGAIN;
669 return 0;
670 }
671 EXPORT_SYMBOL(__getnstimeofday64);
672
673 /**
674 * getnstimeofday64 - Returns the time of day in a timespec64.
675 * @ts: pointer to the timespec64 to be set
676 *
677 * Returns the time of day in a timespec64 (WARN if suspended).
678 */
679 void getnstimeofday64(struct timespec64 *ts)
680 {
681 WARN_ON(__getnstimeofday64(ts));
682 }
683 EXPORT_SYMBOL(getnstimeofday64);
684
685 ktime_t ktime_get(void)
686 {
687 struct timekeeper *tk = &tk_core.timekeeper;
688 unsigned int seq;
689 ktime_t base;
690 s64 nsecs;
691
692 WARN_ON(timekeeping_suspended);
693
694 do {
695 seq = read_seqcount_begin(&tk_core.seq);
696 base = tk->tkr_mono.base;
697 nsecs = timekeeping_get_ns(&tk->tkr_mono);
698
699 } while (read_seqcount_retry(&tk_core.seq, seq));
700
701 return ktime_add_ns(base, nsecs);
702 }
703 EXPORT_SYMBOL_GPL(ktime_get);
704
705 u32 ktime_get_resolution_ns(void)
706 {
707 struct timekeeper *tk = &tk_core.timekeeper;
708 unsigned int seq;
709 u32 nsecs;
710
711 WARN_ON(timekeeping_suspended);
712
713 do {
714 seq = read_seqcount_begin(&tk_core.seq);
715 nsecs = tk->tkr_mono.mult >> tk->tkr_mono.shift;
716 } while (read_seqcount_retry(&tk_core.seq, seq));
717
718 return nsecs;
719 }
720 EXPORT_SYMBOL_GPL(ktime_get_resolution_ns);
721
722 static ktime_t *offsets[TK_OFFS_MAX] = {
723 [TK_OFFS_REAL] = &tk_core.timekeeper.offs_real,
724 [TK_OFFS_BOOT] = &tk_core.timekeeper.offs_boot,
725 [TK_OFFS_TAI] = &tk_core.timekeeper.offs_tai,
726 };
727
728 ktime_t ktime_get_with_offset(enum tk_offsets offs)
729 {
730 struct timekeeper *tk = &tk_core.timekeeper;
731 unsigned int seq;
732 ktime_t base, *offset = offsets[offs];
733 s64 nsecs;
734
735 WARN_ON(timekeeping_suspended);
736
737 do {
738 seq = read_seqcount_begin(&tk_core.seq);
739 base = ktime_add(tk->tkr_mono.base, *offset);
740 nsecs = timekeeping_get_ns(&tk->tkr_mono);
741
742 } while (read_seqcount_retry(&tk_core.seq, seq));
743
744 return ktime_add_ns(base, nsecs);
745
746 }
747 EXPORT_SYMBOL_GPL(ktime_get_with_offset);
748
749 /**
750 * ktime_mono_to_any() - convert mononotic time to any other time
751 * @tmono: time to convert.
752 * @offs: which offset to use
753 */
754 ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs)
755 {
756 ktime_t *offset = offsets[offs];
757 unsigned long seq;
758 ktime_t tconv;
759
760 do {
761 seq = read_seqcount_begin(&tk_core.seq);
762 tconv = ktime_add(tmono, *offset);
763 } while (read_seqcount_retry(&tk_core.seq, seq));
764
765 return tconv;
766 }
767 EXPORT_SYMBOL_GPL(ktime_mono_to_any);
768
769 /**
770 * ktime_get_raw - Returns the raw monotonic time in ktime_t format
771 */
772 ktime_t ktime_get_raw(void)
773 {
774 struct timekeeper *tk = &tk_core.timekeeper;
775 unsigned int seq;
776 ktime_t base;
777 s64 nsecs;
778
779 do {
780 seq = read_seqcount_begin(&tk_core.seq);
781 base = tk->tkr_raw.base;
782 nsecs = timekeeping_get_ns(&tk->tkr_raw);
783
784 } while (read_seqcount_retry(&tk_core.seq, seq));
785
786 return ktime_add_ns(base, nsecs);
787 }
788 EXPORT_SYMBOL_GPL(ktime_get_raw);
789
790 /**
791 * ktime_get_ts64 - get the monotonic clock in timespec64 format
792 * @ts: pointer to timespec variable
793 *
794 * The function calculates the monotonic clock from the realtime
795 * clock and the wall_to_monotonic offset and stores the result
796 * in normalized timespec64 format in the variable pointed to by @ts.
797 */
798 void ktime_get_ts64(struct timespec64 *ts)
799 {
800 struct timekeeper *tk = &tk_core.timekeeper;
801 struct timespec64 tomono;
802 s64 nsec;
803 unsigned int seq;
804
805 WARN_ON(timekeeping_suspended);
806
807 do {
808 seq = read_seqcount_begin(&tk_core.seq);
809 ts->tv_sec = tk->xtime_sec;
810 nsec = timekeeping_get_ns(&tk->tkr_mono);
811 tomono = tk->wall_to_monotonic;
812
813 } while (read_seqcount_retry(&tk_core.seq, seq));
814
815 ts->tv_sec += tomono.tv_sec;
816 ts->tv_nsec = 0;
817 timespec64_add_ns(ts, nsec + tomono.tv_nsec);
818 }
819 EXPORT_SYMBOL_GPL(ktime_get_ts64);
820
821 /**
822 * ktime_get_seconds - Get the seconds portion of CLOCK_MONOTONIC
823 *
824 * Returns the seconds portion of CLOCK_MONOTONIC with a single non
825 * serialized read. tk->ktime_sec is of type 'unsigned long' so this
826 * works on both 32 and 64 bit systems. On 32 bit systems the readout
827 * covers ~136 years of uptime which should be enough to prevent
828 * premature wrap arounds.
829 */
830 time64_t ktime_get_seconds(void)
831 {
832 struct timekeeper *tk = &tk_core.timekeeper;
833
834 WARN_ON(timekeeping_suspended);
835 return tk->ktime_sec;
836 }
837 EXPORT_SYMBOL_GPL(ktime_get_seconds);
838
839 /**
840 * ktime_get_real_seconds - Get the seconds portion of CLOCK_REALTIME
841 *
842 * Returns the wall clock seconds since 1970. This replaces the
843 * get_seconds() interface which is not y2038 safe on 32bit systems.
844 *
845 * For 64bit systems the fast access to tk->xtime_sec is preserved. On
846 * 32bit systems the access must be protected with the sequence
847 * counter to provide "atomic" access to the 64bit tk->xtime_sec
848 * value.
849 */
850 time64_t ktime_get_real_seconds(void)
851 {
852 struct timekeeper *tk = &tk_core.timekeeper;
853 time64_t seconds;
854 unsigned int seq;
855
856 if (IS_ENABLED(CONFIG_64BIT))
857 return tk->xtime_sec;
858
859 do {
860 seq = read_seqcount_begin(&tk_core.seq);
861 seconds = tk->xtime_sec;
862
863 } while (read_seqcount_retry(&tk_core.seq, seq));
864
865 return seconds;
866 }
867 EXPORT_SYMBOL_GPL(ktime_get_real_seconds);
868
869 #ifdef CONFIG_NTP_PPS
870
871 /**
872 * getnstime_raw_and_real - get day and raw monotonic time in timespec format
873 * @ts_raw: pointer to the timespec to be set to raw monotonic time
874 * @ts_real: pointer to the timespec to be set to the time of day
875 *
876 * This function reads both the time of day and raw monotonic time at the
877 * same time atomically and stores the resulting timestamps in timespec
878 * format.
879 */
880 void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real)
881 {
882 struct timekeeper *tk = &tk_core.timekeeper;
883 unsigned long seq;
884 s64 nsecs_raw, nsecs_real;
885
886 WARN_ON_ONCE(timekeeping_suspended);
887
888 do {
889 seq = read_seqcount_begin(&tk_core.seq);
890
891 *ts_raw = timespec64_to_timespec(tk->raw_time);
892 ts_real->tv_sec = tk->xtime_sec;
893 ts_real->tv_nsec = 0;
894
895 nsecs_raw = timekeeping_get_ns(&tk->tkr_raw);
896 nsecs_real = timekeeping_get_ns(&tk->tkr_mono);
897
898 } while (read_seqcount_retry(&tk_core.seq, seq));
899
900 timespec_add_ns(ts_raw, nsecs_raw);
901 timespec_add_ns(ts_real, nsecs_real);
902 }
903 EXPORT_SYMBOL(getnstime_raw_and_real);
904
905 #endif /* CONFIG_NTP_PPS */
906
907 /**
908 * do_gettimeofday - Returns the time of day in a timeval
909 * @tv: pointer to the timeval to be set
910 *
911 * NOTE: Users should be converted to using getnstimeofday()
912 */
913 void do_gettimeofday(struct timeval *tv)
914 {
915 struct timespec64 now;
916
917 getnstimeofday64(&now);
918 tv->tv_sec = now.tv_sec;
919 tv->tv_usec = now.tv_nsec/1000;
920 }
921 EXPORT_SYMBOL(do_gettimeofday);
922
923 /**
924 * do_settimeofday64 - Sets the time of day.
925 * @ts: pointer to the timespec64 variable containing the new time
926 *
927 * Sets the time of day to the new time and update NTP and notify hrtimers
928 */
929 int do_settimeofday64(const struct timespec64 *ts)
930 {
931 struct timekeeper *tk = &tk_core.timekeeper;
932 struct timespec64 ts_delta, xt;
933 unsigned long flags;
934
935 if (!timespec64_valid_strict(ts))
936 return -EINVAL;
937
938 raw_spin_lock_irqsave(&timekeeper_lock, flags);
939 write_seqcount_begin(&tk_core.seq);
940
941 timekeeping_forward_now(tk);
942
943 xt = tk_xtime(tk);
944 ts_delta.tv_sec = ts->tv_sec - xt.tv_sec;
945 ts_delta.tv_nsec = ts->tv_nsec - xt.tv_nsec;
946
947 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));
948
949 tk_set_xtime(tk, ts);
950
951 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
952
953 write_seqcount_end(&tk_core.seq);
954 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
955
956 /* signal hrtimers about time change */
957 clock_was_set();
958
959 return 0;
960 }
961 EXPORT_SYMBOL(do_settimeofday64);
962
963 /**
964 * timekeeping_inject_offset - Adds or subtracts from the current time.
965 * @tv: pointer to the timespec variable containing the offset
966 *
967 * Adds or subtracts an offset value from the current time.
968 */
969 int timekeeping_inject_offset(struct timespec *ts)
970 {
971 struct timekeeper *tk = &tk_core.timekeeper;
972 unsigned long flags;
973 struct timespec64 ts64, tmp;
974 int ret = 0;
975
976 if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
977 return -EINVAL;
978
979 ts64 = timespec_to_timespec64(*ts);
980
981 raw_spin_lock_irqsave(&timekeeper_lock, flags);
982 write_seqcount_begin(&tk_core.seq);
983
984 timekeeping_forward_now(tk);
985
986 /* Make sure the proposed value is valid */
987 tmp = timespec64_add(tk_xtime(tk), ts64);
988 if (!timespec64_valid_strict(&tmp)) {
989 ret = -EINVAL;
990 goto error;
991 }
992
993 tk_xtime_add(tk, &ts64);
994 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts64));
995
996 error: /* even if we error out, we forwarded the time, so call update */
997 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
998
999 write_seqcount_end(&tk_core.seq);
1000 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1001
1002 /* signal hrtimers about time change */
1003 clock_was_set();
1004
1005 return ret;
1006 }
1007 EXPORT_SYMBOL(timekeeping_inject_offset);
1008
1009
1010 /**
1011 * timekeeping_get_tai_offset - Returns current TAI offset from UTC
1012 *
1013 */
1014 s32 timekeeping_get_tai_offset(void)
1015 {
1016 struct timekeeper *tk = &tk_core.timekeeper;
1017 unsigned int seq;
1018 s32 ret;
1019
1020 do {
1021 seq = read_seqcount_begin(&tk_core.seq);
1022 ret = tk->tai_offset;
1023 } while (read_seqcount_retry(&tk_core.seq, seq));
1024
1025 return ret;
1026 }
1027
1028 /**
1029 * __timekeeping_set_tai_offset - Lock free worker function
1030 *
1031 */
1032 static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset)
1033 {
1034 tk->tai_offset = tai_offset;
1035 tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tai_offset, 0));
1036 }
1037
1038 /**
1039 * timekeeping_set_tai_offset - Sets the current TAI offset from UTC
1040 *
1041 */
1042 void timekeeping_set_tai_offset(s32 tai_offset)
1043 {
1044 struct timekeeper *tk = &tk_core.timekeeper;
1045 unsigned long flags;
1046
1047 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1048 write_seqcount_begin(&tk_core.seq);
1049 __timekeeping_set_tai_offset(tk, tai_offset);
1050 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1051 write_seqcount_end(&tk_core.seq);
1052 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1053 clock_was_set();
1054 }
1055
1056 /**
1057 * change_clocksource - Swaps clocksources if a new one is available
1058 *
1059 * Accumulates current time interval and initializes new clocksource
1060 */
1061 static int change_clocksource(void *data)
1062 {
1063 struct timekeeper *tk = &tk_core.timekeeper;
1064 struct clocksource *new, *old;
1065 unsigned long flags;
1066
1067 new = (struct clocksource *) data;
1068
1069 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1070 write_seqcount_begin(&tk_core.seq);
1071
1072 timekeeping_forward_now(tk);
1073 /*
1074 * If the cs is in module, get a module reference. Succeeds
1075 * for built-in code (owner == NULL) as well.
1076 */
1077 if (try_module_get(new->owner)) {
1078 if (!new->enable || new->enable(new) == 0) {
1079 old = tk->tkr_mono.clock;
1080 tk_setup_internals(tk, new);
1081 if (old->disable)
1082 old->disable(old);
1083 module_put(old->owner);
1084 } else {
1085 module_put(new->owner);
1086 }
1087 }
1088 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1089
1090 write_seqcount_end(&tk_core.seq);
1091 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1092
1093 return 0;
1094 }
1095
1096 /**
1097 * timekeeping_notify - Install a new clock source
1098 * @clock: pointer to the clock source
1099 *
1100 * This function is called from clocksource.c after a new, better clock
1101 * source has been registered. The caller holds the clocksource_mutex.
1102 */
1103 int timekeeping_notify(struct clocksource *clock)
1104 {
1105 struct timekeeper *tk = &tk_core.timekeeper;
1106
1107 if (tk->tkr_mono.clock == clock)
1108 return 0;
1109 stop_machine(change_clocksource, clock, NULL);
1110 tick_clock_notify();
1111 return tk->tkr_mono.clock == clock ? 0 : -1;
1112 }
1113
1114 /**
1115 * getrawmonotonic64 - Returns the raw monotonic time in a timespec
1116 * @ts: pointer to the timespec64 to be set
1117 *
1118 * Returns the raw monotonic time (completely un-modified by ntp)
1119 */
1120 void getrawmonotonic64(struct timespec64 *ts)
1121 {
1122 struct timekeeper *tk = &tk_core.timekeeper;
1123 struct timespec64 ts64;
1124 unsigned long seq;
1125 s64 nsecs;
1126
1127 do {
1128 seq = read_seqcount_begin(&tk_core.seq);
1129 nsecs = timekeeping_get_ns(&tk->tkr_raw);
1130 ts64 = tk->raw_time;
1131
1132 } while (read_seqcount_retry(&tk_core.seq, seq));
1133
1134 timespec64_add_ns(&ts64, nsecs);
1135 *ts = ts64;
1136 }
1137 EXPORT_SYMBOL(getrawmonotonic64);
1138
1139
1140 /**
1141 * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
1142 */
1143 int timekeeping_valid_for_hres(void)
1144 {
1145 struct timekeeper *tk = &tk_core.timekeeper;
1146 unsigned long seq;
1147 int ret;
1148
1149 do {
1150 seq = read_seqcount_begin(&tk_core.seq);
1151
1152 ret = tk->tkr_mono.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
1153
1154 } while (read_seqcount_retry(&tk_core.seq, seq));
1155
1156 return ret;
1157 }
1158
1159 /**
1160 * timekeeping_max_deferment - Returns max time the clocksource can be deferred
1161 */
1162 u64 timekeeping_max_deferment(void)
1163 {
1164 struct timekeeper *tk = &tk_core.timekeeper;
1165 unsigned long seq;
1166 u64 ret;
1167
1168 do {
1169 seq = read_seqcount_begin(&tk_core.seq);
1170
1171 ret = tk->tkr_mono.clock->max_idle_ns;
1172
1173 } while (read_seqcount_retry(&tk_core.seq, seq));
1174
1175 return ret;
1176 }
1177
1178 /**
1179 * read_persistent_clock - Return time from the persistent clock.
1180 *
1181 * Weak dummy function for arches that do not yet support it.
1182 * Reads the time from the battery backed persistent clock.
1183 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
1184 *
1185 * XXX - Do be sure to remove it once all arches implement it.
1186 */
1187 void __weak read_persistent_clock(struct timespec *ts)
1188 {
1189 ts->tv_sec = 0;
1190 ts->tv_nsec = 0;
1191 }
1192
1193 void __weak read_persistent_clock64(struct timespec64 *ts64)
1194 {
1195 struct timespec ts;
1196
1197 read_persistent_clock(&ts);
1198 *ts64 = timespec_to_timespec64(ts);
1199 }
1200
1201 /**
1202 * read_boot_clock - Return time of the system start.
1203 *
1204 * Weak dummy function for arches that do not yet support it.
1205 * Function to read the exact time the system has been started.
1206 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
1207 *
1208 * XXX - Do be sure to remove it once all arches implement it.
1209 */
1210 void __weak read_boot_clock(struct timespec *ts)
1211 {
1212 ts->tv_sec = 0;
1213 ts->tv_nsec = 0;
1214 }
1215
1216 void __weak read_boot_clock64(struct timespec64 *ts64)
1217 {
1218 struct timespec ts;
1219
1220 read_boot_clock(&ts);
1221 *ts64 = timespec_to_timespec64(ts);
1222 }
1223
1224 /* Flag for if timekeeping_resume() has injected sleeptime */
1225 static bool sleeptime_injected;
1226
1227 /* Flag for if there is a persistent clock on this platform */
1228 static bool persistent_clock_exists;
1229
1230 /*
1231 * timekeeping_init - Initializes the clocksource and common timekeeping values
1232 */
1233 void __init timekeeping_init(void)
1234 {
1235 struct timekeeper *tk = &tk_core.timekeeper;
1236 struct clocksource *clock;
1237 unsigned long flags;
1238 struct timespec64 now, boot, tmp;
1239
1240 read_persistent_clock64(&now);
1241 if (!timespec64_valid_strict(&now)) {
1242 pr_warn("WARNING: Persistent clock returned invalid value!\n"
1243 " Check your CMOS/BIOS settings.\n");
1244 now.tv_sec = 0;
1245 now.tv_nsec = 0;
1246 } else if (now.tv_sec || now.tv_nsec)
1247 persistent_clock_exists = true;
1248
1249 read_boot_clock64(&boot);
1250 if (!timespec64_valid_strict(&boot)) {
1251 pr_warn("WARNING: Boot clock returned invalid value!\n"
1252 " Check your CMOS/BIOS settings.\n");
1253 boot.tv_sec = 0;
1254 boot.tv_nsec = 0;
1255 }
1256
1257 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1258 write_seqcount_begin(&tk_core.seq);
1259 ntp_init();
1260
1261 clock = clocksource_default_clock();
1262 if (clock->enable)
1263 clock->enable(clock);
1264 tk_setup_internals(tk, clock);
1265
1266 tk_set_xtime(tk, &now);
1267 tk->raw_time.tv_sec = 0;
1268 tk->raw_time.tv_nsec = 0;
1269 if (boot.tv_sec == 0 && boot.tv_nsec == 0)
1270 boot = tk_xtime(tk);
1271
1272 set_normalized_timespec64(&tmp, -boot.tv_sec, -boot.tv_nsec);
1273 tk_set_wall_to_mono(tk, tmp);
1274
1275 timekeeping_update(tk, TK_MIRROR);
1276
1277 write_seqcount_end(&tk_core.seq);
1278 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1279 }
1280
1281 /* time in seconds when suspend began for persistent clock */
1282 static struct timespec64 timekeeping_suspend_time;
1283
1284 /**
1285 * __timekeeping_inject_sleeptime - Internal function to add sleep interval
1286 * @delta: pointer to a timespec delta value
1287 *
1288 * Takes a timespec offset measuring a suspend interval and properly
1289 * adds the sleep offset to the timekeeping variables.
1290 */
1291 static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
1292 struct timespec64 *delta)
1293 {
1294 if (!timespec64_valid_strict(delta)) {
1295 printk_deferred(KERN_WARNING
1296 "__timekeeping_inject_sleeptime: Invalid "
1297 "sleep delta value!\n");
1298 return;
1299 }
1300 tk_xtime_add(tk, delta);
1301 tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *delta));
1302 tk_update_sleep_time(tk, timespec64_to_ktime(*delta));
1303 tk_debug_account_sleep_time(delta);
1304 }
1305
1306 #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
1307 /**
1308 * We have three kinds of time sources to use for sleep time
1309 * injection, the preference order is:
1310 * 1) non-stop clocksource
1311 * 2) persistent clock (ie: RTC accessible when irqs are off)
1312 * 3) RTC
1313 *
1314 * 1) and 2) are used by timekeeping, 3) by RTC subsystem.
1315 * If system has neither 1) nor 2), 3) will be used finally.
1316 *
1317 *
1318 * If timekeeping has injected sleeptime via either 1) or 2),
1319 * 3) becomes needless, so in this case we don't need to call
1320 * rtc_resume(), and this is what timekeeping_rtc_skipresume()
1321 * means.
1322 */
1323 bool timekeeping_rtc_skipresume(void)
1324 {
1325 return sleeptime_injected;
1326 }
1327
1328 /**
1329 * 1) can be determined whether to use or not only when doing
1330 * timekeeping_resume() which is invoked after rtc_suspend(),
1331 * so we can't skip rtc_suspend() surely if system has 1).
1332 *
1333 * But if system has 2), 2) will definitely be used, so in this
1334 * case we don't need to call rtc_suspend(), and this is what
1335 * timekeeping_rtc_skipsuspend() means.
1336 */
1337 bool timekeeping_rtc_skipsuspend(void)
1338 {
1339 return persistent_clock_exists;
1340 }
1341
1342 /**
1343 * timekeeping_inject_sleeptime64 - Adds suspend interval to timeekeeping values
1344 * @delta: pointer to a timespec64 delta value
1345 *
1346 * This hook is for architectures that cannot support read_persistent_clock64
1347 * because their RTC/persistent clock is only accessible when irqs are enabled.
1348 * and also don't have an effective nonstop clocksource.
1349 *
1350 * This function should only be called by rtc_resume(), and allows
1351 * a suspend offset to be injected into the timekeeping values.
1352 */
1353 void timekeeping_inject_sleeptime64(struct timespec64 *delta)
1354 {
1355 struct timekeeper *tk = &tk_core.timekeeper;
1356 unsigned long flags;
1357
1358 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1359 write_seqcount_begin(&tk_core.seq);
1360
1361 timekeeping_forward_now(tk);
1362
1363 __timekeeping_inject_sleeptime(tk, delta);
1364
1365 timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1366
1367 write_seqcount_end(&tk_core.seq);
1368 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1369
1370 /* signal hrtimers about time change */
1371 clock_was_set();
1372 }
1373 #endif
1374
1375 /**
1376 * timekeeping_resume - Resumes the generic timekeeping subsystem.
1377 */
1378 void timekeeping_resume(void)
1379 {
1380 struct timekeeper *tk = &tk_core.timekeeper;
1381 struct clocksource *clock = tk->tkr_mono.clock;
1382 unsigned long flags;
1383 struct timespec64 ts_new, ts_delta;
1384 cycle_t cycle_now, cycle_delta;
1385
1386 sleeptime_injected = false;
1387 read_persistent_clock64(&ts_new);
1388
1389 clockevents_resume();
1390 clocksource_resume();
1391
1392 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1393 write_seqcount_begin(&tk_core.seq);
1394
1395 /*
1396 * After system resumes, we need to calculate the suspended time and
1397 * compensate it for the OS time. There are 3 sources that could be
1398 * used: Nonstop clocksource during suspend, persistent clock and rtc
1399 * device.
1400 *
1401 * One specific platform may have 1 or 2 or all of them, and the
1402 * preference will be:
1403 * suspend-nonstop clocksource -> persistent clock -> rtc
1404 * The less preferred source will only be tried if there is no better
1405 * usable source. The rtc part is handled separately in rtc core code.
1406 */
1407 cycle_now = tk->tkr_mono.read(clock);
1408 if ((clock->flags & CLOCK_SOURCE_SUSPEND_NONSTOP) &&
1409 cycle_now > tk->tkr_mono.cycle_last) {
1410 u64 num, max = ULLONG_MAX;
1411 u32 mult = clock->mult;
1412 u32 shift = clock->shift;
1413 s64 nsec = 0;
1414
1415 cycle_delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last,
1416 tk->tkr_mono.mask);
1417
1418 /*
1419 * "cycle_delta * mutl" may cause 64 bits overflow, if the
1420 * suspended time is too long. In that case we need do the
1421 * 64 bits math carefully
1422 */
1423 do_div(max, mult);
1424 if (cycle_delta > max) {
1425 num = div64_u64(cycle_delta, max);
1426 nsec = (((u64) max * mult) >> shift) * num;
1427 cycle_delta -= num * max;
1428 }
1429 nsec += ((u64) cycle_delta * mult) >> shift;
1430
1431 ts_delta = ns_to_timespec64(nsec);
1432 sleeptime_injected = true;
1433 } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) {
1434 ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time);
1435 sleeptime_injected = true;
1436 }
1437
1438 if (sleeptime_injected)
1439 __timekeeping_inject_sleeptime(tk, &ts_delta);
1440
1441 /* Re-base the last cycle value */
1442 tk->tkr_mono.cycle_last = cycle_now;
1443 tk->tkr_raw.cycle_last = cycle_now;
1444
1445 tk->ntp_error = 0;
1446 timekeeping_suspended = 0;
1447 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1448 write_seqcount_end(&tk_core.seq);
1449 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1450
1451 touch_softlockup_watchdog();
1452
1453 tick_resume();
1454 hrtimers_resume();
1455 }
1456
1457 int timekeeping_suspend(void)
1458 {
1459 struct timekeeper *tk = &tk_core.timekeeper;
1460 unsigned long flags;
1461 struct timespec64 delta, delta_delta;
1462 static struct timespec64 old_delta;
1463
1464 read_persistent_clock64(&timekeeping_suspend_time);
1465
1466 /*
1467 * On some systems the persistent_clock can not be detected at
1468 * timekeeping_init by its return value, so if we see a valid
1469 * value returned, update the persistent_clock_exists flag.
1470 */
1471 if (timekeeping_suspend_time.tv_sec || timekeeping_suspend_time.tv_nsec)
1472 persistent_clock_exists = true;
1473
1474 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1475 write_seqcount_begin(&tk_core.seq);
1476 timekeeping_forward_now(tk);
1477 timekeeping_suspended = 1;
1478
1479 if (persistent_clock_exists) {
1480 /*
1481 * To avoid drift caused by repeated suspend/resumes,
1482 * which each can add ~1 second drift error,
1483 * try to compensate so the difference in system time
1484 * and persistent_clock time stays close to constant.
1485 */
1486 delta = timespec64_sub(tk_xtime(tk), timekeeping_suspend_time);
1487 delta_delta = timespec64_sub(delta, old_delta);
1488 if (abs(delta_delta.tv_sec) >= 2) {
1489 /*
1490 * if delta_delta is too large, assume time correction
1491 * has occurred and set old_delta to the current delta.
1492 */
1493 old_delta = delta;
1494 } else {
1495 /* Otherwise try to adjust old_system to compensate */
1496 timekeeping_suspend_time =
1497 timespec64_add(timekeeping_suspend_time, delta_delta);
1498 }
1499 }
1500
1501 timekeeping_update(tk, TK_MIRROR);
1502 halt_fast_timekeeper(tk);
1503 write_seqcount_end(&tk_core.seq);
1504 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1505
1506 tick_suspend();
1507 clocksource_suspend();
1508 clockevents_suspend();
1509
1510 return 0;
1511 }
1512
1513 /* sysfs resume/suspend bits for timekeeping */
1514 static struct syscore_ops timekeeping_syscore_ops = {
1515 .resume = timekeeping_resume,
1516 .suspend = timekeeping_suspend,
1517 };
1518
1519 static int __init timekeeping_init_ops(void)
1520 {
1521 register_syscore_ops(&timekeeping_syscore_ops);
1522 return 0;
1523 }
1524 device_initcall(timekeeping_init_ops);
1525
1526 /*
1527 * Apply a multiplier adjustment to the timekeeper
1528 */
1529 static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk,
1530 s64 offset,
1531 bool negative,
1532 int adj_scale)
1533 {
1534 s64 interval = tk->cycle_interval;
1535 s32 mult_adj = 1;
1536
1537 if (negative) {
1538 mult_adj = -mult_adj;
1539 interval = -interval;
1540 offset = -offset;
1541 }
1542 mult_adj <<= adj_scale;
1543 interval <<= adj_scale;
1544 offset <<= adj_scale;
1545
1546 /*
1547 * So the following can be confusing.
1548 *
1549 * To keep things simple, lets assume mult_adj == 1 for now.
1550 *
1551 * When mult_adj != 1, remember that the interval and offset values
1552 * have been appropriately scaled so the math is the same.
1553 *
1554 * The basic idea here is that we're increasing the multiplier
1555 * by one, this causes the xtime_interval to be incremented by
1556 * one cycle_interval. This is because:
1557 * xtime_interval = cycle_interval * mult
1558 * So if mult is being incremented by one:
1559 * xtime_interval = cycle_interval * (mult + 1)
1560 * Its the same as:
1561 * xtime_interval = (cycle_interval * mult) + cycle_interval
1562 * Which can be shortened to:
1563 * xtime_interval += cycle_interval
1564 *
1565 * So offset stores the non-accumulated cycles. Thus the current
1566 * time (in shifted nanoseconds) is:
1567 * now = (offset * adj) + xtime_nsec
1568 * Now, even though we're adjusting the clock frequency, we have
1569 * to keep time consistent. In other words, we can't jump back
1570 * in time, and we also want to avoid jumping forward in time.
1571 *
1572 * So given the same offset value, we need the time to be the same
1573 * both before and after the freq adjustment.
1574 * now = (offset * adj_1) + xtime_nsec_1
1575 * now = (offset * adj_2) + xtime_nsec_2
1576 * So:
1577 * (offset * adj_1) + xtime_nsec_1 =
1578 * (offset * adj_2) + xtime_nsec_2
1579 * And we know:
1580 * adj_2 = adj_1 + 1
1581 * So:
1582 * (offset * adj_1) + xtime_nsec_1 =
1583 * (offset * (adj_1+1)) + xtime_nsec_2
1584 * (offset * adj_1) + xtime_nsec_1 =
1585 * (offset * adj_1) + offset + xtime_nsec_2
1586 * Canceling the sides:
1587 * xtime_nsec_1 = offset + xtime_nsec_2
1588 * Which gives us:
1589 * xtime_nsec_2 = xtime_nsec_1 - offset
1590 * Which simplfies to:
1591 * xtime_nsec -= offset
1592 *
1593 * XXX - TODO: Doc ntp_error calculation.
1594 */
1595 if ((mult_adj > 0) && (tk->tkr_mono.mult + mult_adj < mult_adj)) {
1596 /* NTP adjustment caused clocksource mult overflow */
1597 WARN_ON_ONCE(1);
1598 return;
1599 }
1600
1601 tk->tkr_mono.mult += mult_adj;
1602 tk->xtime_interval += interval;
1603 tk->tkr_mono.xtime_nsec -= offset;
1604 tk->ntp_error -= (interval - offset) << tk->ntp_error_shift;
1605 }
1606
1607 /*
1608 * Calculate the multiplier adjustment needed to match the frequency
1609 * specified by NTP
1610 */
1611 static __always_inline void timekeeping_freqadjust(struct timekeeper *tk,
1612 s64 offset)
1613 {
1614 s64 interval = tk->cycle_interval;
1615 s64 xinterval = tk->xtime_interval;
1616 s64 tick_error;
1617 bool negative;
1618 u32 adj;
1619
1620 /* Remove any current error adj from freq calculation */
1621 if (tk->ntp_err_mult)
1622 xinterval -= tk->cycle_interval;
1623
1624 tk->ntp_tick = ntp_tick_length();
1625
1626 /* Calculate current error per tick */
1627 tick_error = ntp_tick_length() >> tk->ntp_error_shift;
1628 tick_error -= (xinterval + tk->xtime_remainder);
1629
1630 /* Don't worry about correcting it if its small */
1631 if (likely((tick_error >= 0) && (tick_error <= interval)))
1632 return;
1633
1634 /* preserve the direction of correction */
1635 negative = (tick_error < 0);
1636
1637 /* Sort out the magnitude of the correction */
1638 tick_error = abs(tick_error);
1639 for (adj = 0; tick_error > interval; adj++)
1640 tick_error >>= 1;
1641
1642 /* scale the corrections */
1643 timekeeping_apply_adjustment(tk, offset, negative, adj);
1644 }
1645
1646 /*
1647 * Adjust the timekeeper's multiplier to the correct frequency
1648 * and also to reduce the accumulated error value.
1649 */
1650 static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
1651 {
1652 /* Correct for the current frequency error */
1653 timekeeping_freqadjust(tk, offset);
1654
1655 /* Next make a small adjustment to fix any cumulative error */
1656 if (!tk->ntp_err_mult && (tk->ntp_error > 0)) {
1657 tk->ntp_err_mult = 1;
1658 timekeeping_apply_adjustment(tk, offset, 0, 0);
1659 } else if (tk->ntp_err_mult && (tk->ntp_error <= 0)) {
1660 /* Undo any existing error adjustment */
1661 timekeeping_apply_adjustment(tk, offset, 1, 0);
1662 tk->ntp_err_mult = 0;
1663 }
1664
1665 if (unlikely(tk->tkr_mono.clock->maxadj &&
1666 (abs(tk->tkr_mono.mult - tk->tkr_mono.clock->mult)
1667 > tk->tkr_mono.clock->maxadj))) {
1668 printk_once(KERN_WARNING
1669 "Adjusting %s more than 11%% (%ld vs %ld)\n",
1670 tk->tkr_mono.clock->name, (long)tk->tkr_mono.mult,
1671 (long)tk->tkr_mono.clock->mult + tk->tkr_mono.clock->maxadj);
1672 }
1673
1674 /*
1675 * It may be possible that when we entered this function, xtime_nsec
1676 * was very small. Further, if we're slightly speeding the clocksource
1677 * in the code above, its possible the required corrective factor to
1678 * xtime_nsec could cause it to underflow.
1679 *
1680 * Now, since we already accumulated the second, cannot simply roll
1681 * the accumulated second back, since the NTP subsystem has been
1682 * notified via second_overflow. So instead we push xtime_nsec forward
1683 * by the amount we underflowed, and add that amount into the error.
1684 *
1685 * We'll correct this error next time through this function, when
1686 * xtime_nsec is not as small.
1687 */
1688 if (unlikely((s64)tk->tkr_mono.xtime_nsec < 0)) {
1689 s64 neg = -(s64)tk->tkr_mono.xtime_nsec;
1690 tk->tkr_mono.xtime_nsec = 0;
1691 tk->ntp_error += neg << tk->ntp_error_shift;
1692 }
1693 }
1694
1695 /**
1696 * accumulate_nsecs_to_secs - Accumulates nsecs into secs
1697 *
1698 * Helper function that accumulates a the nsecs greater then a second
1699 * from the xtime_nsec field to the xtime_secs field.
1700 * It also calls into the NTP code to handle leapsecond processing.
1701 *
1702 */
1703 static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper *tk)
1704 {
1705 u64 nsecps = (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
1706 unsigned int clock_set = 0;
1707
1708 while (tk->tkr_mono.xtime_nsec >= nsecps) {
1709 int leap;
1710
1711 tk->tkr_mono.xtime_nsec -= nsecps;
1712 tk->xtime_sec++;
1713
1714 /* Figure out if its a leap sec and apply if needed */
1715 leap = second_overflow(tk->xtime_sec);
1716 if (unlikely(leap)) {
1717 struct timespec64 ts;
1718
1719 tk->xtime_sec += leap;
1720
1721 ts.tv_sec = leap;
1722 ts.tv_nsec = 0;
1723 tk_set_wall_to_mono(tk,
1724 timespec64_sub(tk->wall_to_monotonic, ts));
1725
1726 __timekeeping_set_tai_offset(tk, tk->tai_offset - leap);
1727
1728 clock_set = TK_CLOCK_WAS_SET;
1729 }
1730 }
1731 return clock_set;
1732 }
1733
1734 /**
1735 * logarithmic_accumulation - shifted accumulation of cycles
1736 *
1737 * This functions accumulates a shifted interval of cycles into
1738 * into a shifted interval nanoseconds. Allows for O(log) accumulation
1739 * loop.
1740 *
1741 * Returns the unconsumed cycles.
1742 */
1743 static cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset,
1744 u32 shift,
1745 unsigned int *clock_set)
1746 {
1747 cycle_t interval = tk->cycle_interval << shift;
1748 u64 raw_nsecs;
1749
1750 /* If the offset is smaller then a shifted interval, do nothing */
1751 if (offset < interval)
1752 return offset;
1753
1754 /* Accumulate one shifted interval */
1755 offset -= interval;
1756 tk->tkr_mono.cycle_last += interval;
1757 tk->tkr_raw.cycle_last += interval;
1758
1759 tk->tkr_mono.xtime_nsec += tk->xtime_interval << shift;
1760 *clock_set |= accumulate_nsecs_to_secs(tk);
1761
1762 /* Accumulate raw time */
1763 raw_nsecs = (u64)tk->raw_interval << shift;
1764 raw_nsecs += tk->raw_time.tv_nsec;
1765 if (raw_nsecs >= NSEC_PER_SEC) {
1766 u64 raw_secs = raw_nsecs;
1767 raw_nsecs = do_div(raw_secs, NSEC_PER_SEC);
1768 tk->raw_time.tv_sec += raw_secs;
1769 }
1770 tk->raw_time.tv_nsec = raw_nsecs;
1771
1772 /* Accumulate error between NTP and clock interval */
1773 tk->ntp_error += tk->ntp_tick << shift;
1774 tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) <<
1775 (tk->ntp_error_shift + shift);
1776
1777 return offset;
1778 }
1779
1780 /**
1781 * update_wall_time - Uses the current clocksource to increment the wall time
1782 *
1783 */
1784 void update_wall_time(void)
1785 {
1786 struct timekeeper *real_tk = &tk_core.timekeeper;
1787 struct timekeeper *tk = &shadow_timekeeper;
1788 cycle_t offset;
1789 int shift = 0, maxshift;
1790 unsigned int clock_set = 0;
1791 unsigned long flags;
1792
1793 raw_spin_lock_irqsave(&timekeeper_lock, flags);
1794
1795 /* Make sure we're fully resumed: */
1796 if (unlikely(timekeeping_suspended))
1797 goto out;
1798
1799 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
1800 offset = real_tk->cycle_interval;
1801 #else
1802 offset = clocksource_delta(tk->tkr_mono.read(tk->tkr_mono.clock),
1803 tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
1804 #endif
1805
1806 /* Check if there's really nothing to do */
1807 if (offset < real_tk->cycle_interval)
1808 goto out;
1809
1810 /* Do some additional sanity checking */
1811 timekeeping_check_update(real_tk, offset);
1812
1813 /*
1814 * With NO_HZ we may have to accumulate many cycle_intervals
1815 * (think "ticks") worth of time at once. To do this efficiently,
1816 * we calculate the largest doubling multiple of cycle_intervals
1817 * that is smaller than the offset. We then accumulate that
1818 * chunk in one go, and then try to consume the next smaller
1819 * doubled multiple.
1820 */
1821 shift = ilog2(offset) - ilog2(tk->cycle_interval);
1822 shift = max(0, shift);
1823 /* Bound shift to one less than what overflows tick_length */
1824 maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1;
1825 shift = min(shift, maxshift);
1826 while (offset >= tk->cycle_interval) {
1827 offset = logarithmic_accumulation(tk, offset, shift,
1828 &clock_set);
1829 if (offset < tk->cycle_interval<<shift)
1830 shift--;
1831 }
1832
1833 /* correct the clock when NTP error is too big */
1834 timekeeping_adjust(tk, offset);
1835
1836 /*
1837 * XXX This can be killed once everyone converts
1838 * to the new update_vsyscall.
1839 */
1840 old_vsyscall_fixup(tk);
1841
1842 /*
1843 * Finally, make sure that after the rounding
1844 * xtime_nsec isn't larger than NSEC_PER_SEC
1845 */
1846 clock_set |= accumulate_nsecs_to_secs(tk);
1847
1848 write_seqcount_begin(&tk_core.seq);
1849 /*
1850 * Update the real timekeeper.
1851 *
1852 * We could avoid this memcpy by switching pointers, but that
1853 * requires changes to all other timekeeper usage sites as
1854 * well, i.e. move the timekeeper pointer getter into the
1855 * spinlocked/seqcount protected sections. And we trade this
1856 * memcpy under the tk_core.seq against one before we start
1857 * updating.
1858 */
1859 memcpy(real_tk, tk, sizeof(*tk));
1860 timekeeping_update(real_tk, clock_set);
1861 write_seqcount_end(&tk_core.seq);
1862 out:
1863 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1864 if (clock_set)
1865 /* Have to call _delayed version, since in irq context*/
1866 clock_was_set_delayed();
1867 }
1868
1869 /**
1870 * getboottime64 - Return the real time of system boot.
1871 * @ts: pointer to the timespec64 to be set
1872 *
1873 * Returns the wall-time of boot in a timespec64.
1874 *
1875 * This is based on the wall_to_monotonic offset and the total suspend
1876 * time. Calls to settimeofday will affect the value returned (which
1877 * basically means that however wrong your real time clock is at boot time,
1878 * you get the right time here).
1879 */
1880 void getboottime64(struct timespec64 *ts)
1881 {
1882 struct timekeeper *tk = &tk_core.timekeeper;
1883 ktime_t t = ktime_sub(tk->offs_real, tk->offs_boot);
1884
1885 *ts = ktime_to_timespec64(t);
1886 }
1887 EXPORT_SYMBOL_GPL(getboottime64);
1888
1889 unsigned long get_seconds(void)
1890 {
1891 struct timekeeper *tk = &tk_core.timekeeper;
1892
1893 return tk->xtime_sec;
1894 }
1895 EXPORT_SYMBOL(get_seconds);
1896
1897 struct timespec __current_kernel_time(void)
1898 {
1899 struct timekeeper *tk = &tk_core.timekeeper;
1900
1901 return timespec64_to_timespec(tk_xtime(tk));
1902 }
1903
1904 struct timespec current_kernel_time(void)
1905 {
1906 struct timekeeper *tk = &tk_core.timekeeper;
1907 struct timespec64 now;
1908 unsigned long seq;
1909
1910 do {
1911 seq = read_seqcount_begin(&tk_core.seq);
1912
1913 now = tk_xtime(tk);
1914 } while (read_seqcount_retry(&tk_core.seq, seq));
1915
1916 return timespec64_to_timespec(now);
1917 }
1918 EXPORT_SYMBOL(current_kernel_time);
1919
1920 struct timespec64 get_monotonic_coarse64(void)
1921 {
1922 struct timekeeper *tk = &tk_core.timekeeper;
1923 struct timespec64 now, mono;
1924 unsigned long seq;
1925
1926 do {
1927 seq = read_seqcount_begin(&tk_core.seq);
1928
1929 now = tk_xtime(tk);
1930 mono = tk->wall_to_monotonic;
1931 } while (read_seqcount_retry(&tk_core.seq, seq));
1932
1933 set_normalized_timespec64(&now, now.tv_sec + mono.tv_sec,
1934 now.tv_nsec + mono.tv_nsec);
1935
1936 return now;
1937 }
1938
1939 /*
1940 * Must hold jiffies_lock
1941 */
1942 void do_timer(unsigned long ticks)
1943 {
1944 jiffies_64 += ticks;
1945 calc_global_load(ticks);
1946 }
1947
1948 /**
1949 * ktime_get_update_offsets_now - hrtimer helper
1950 * @cwsseq: pointer to check and store the clock was set sequence number
1951 * @offs_real: pointer to storage for monotonic -> realtime offset
1952 * @offs_boot: pointer to storage for monotonic -> boottime offset
1953 * @offs_tai: pointer to storage for monotonic -> clock tai offset
1954 *
1955 * Returns current monotonic time and updates the offsets if the
1956 * sequence number in @cwsseq and timekeeper.clock_was_set_seq are
1957 * different.
1958 *
1959 * Called from hrtimer_interrupt() or retrigger_next_event()
1960 */
1961 ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq, ktime_t *offs_real,
1962 ktime_t *offs_boot, ktime_t *offs_tai)
1963 {
1964 struct timekeeper *tk = &tk_core.timekeeper;
1965 unsigned int seq;
1966 ktime_t base;
1967 u64 nsecs;
1968
1969 do {
1970 seq = read_seqcount_begin(&tk_core.seq);
1971
1972 base = tk->tkr_mono.base;
1973 nsecs = timekeeping_get_ns(&tk->tkr_mono);
1974 if (*cwsseq != tk->clock_was_set_seq) {
1975 *cwsseq = tk->clock_was_set_seq;
1976 *offs_real = tk->offs_real;
1977 *offs_boot = tk->offs_boot;
1978 *offs_tai = tk->offs_tai;
1979 }
1980 } while (read_seqcount_retry(&tk_core.seq, seq));
1981
1982 return ktime_add_ns(base, nsecs);
1983 }
1984
1985 /**
1986 * do_adjtimex() - Accessor function to NTP __do_adjtimex function
1987 */
1988 int do_adjtimex(struct timex *txc)
1989 {
1990 struct timekeeper *tk = &tk_core.timekeeper;
1991 unsigned long flags;
1992 struct timespec64 ts;
1993 s32 orig_tai, tai;
1994 int ret;
1995
1996 /* Validate the data before disabling interrupts */
1997 ret = ntp_validate_timex(txc);
1998 if (ret)
1999 return ret;
2000
2001 if (txc->modes & ADJ_SETOFFSET) {
2002 struct timespec delta;
2003 delta.tv_sec = txc->time.tv_sec;
2004 delta.tv_nsec = txc->time.tv_usec;
2005 if (!(txc->modes & ADJ_NANO))
2006 delta.tv_nsec *= 1000;
2007 ret = timekeeping_inject_offset(&delta);
2008 if (ret)
2009 return ret;
2010 }
2011
2012 getnstimeofday64(&ts);
2013
2014 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2015 write_seqcount_begin(&tk_core.seq);
2016
2017 orig_tai = tai = tk->tai_offset;
2018 ret = __do_adjtimex(txc, &ts, &tai);
2019
2020 if (tai != orig_tai) {
2021 __timekeeping_set_tai_offset(tk, tai);
2022 timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
2023 }
2024 write_seqcount_end(&tk_core.seq);
2025 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2026
2027 if (tai != orig_tai)
2028 clock_was_set();
2029
2030 ntp_notify_cmos_timer();
2031
2032 return ret;
2033 }
2034
2035 #ifdef CONFIG_NTP_PPS
2036 /**
2037 * hardpps() - Accessor function to NTP __hardpps function
2038 */
2039 void hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts)
2040 {
2041 unsigned long flags;
2042
2043 raw_spin_lock_irqsave(&timekeeper_lock, flags);
2044 write_seqcount_begin(&tk_core.seq);
2045
2046 __hardpps(phase_ts, raw_ts);
2047
2048 write_seqcount_end(&tk_core.seq);
2049 raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2050 }
2051 EXPORT_SYMBOL(hardpps);
2052 #endif
2053
2054 /**
2055 * xtime_update() - advances the timekeeping infrastructure
2056 * @ticks: number of ticks, that have elapsed since the last call.
2057 *
2058 * Must be called with interrupts disabled.
2059 */
2060 void xtime_update(unsigned long ticks)
2061 {
2062 write_seqlock(&jiffies_lock);
2063 do_timer(ticks);
2064 write_sequnlock(&jiffies_lock);
2065 update_wall_time();
2066 }
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