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b2441318 1// SPDX-License-Identifier: GPL-2.0
4c7ee8de 2/*
4c7ee8de
JS
3 * NTP state machine interfaces and logic.
4 *
5 * This code was mainly moved from kernel/timer.c and kernel/time.c
6 * Please see those files for relevant copyright info and historical
7 * changelogs.
8 */
aa0ac365 9#include <linux/capability.h>
7dffa3c6 10#include <linux/clocksource.h>
eb3f938f 11#include <linux/workqueue.h>
53bbfa9e
IM
12#include <linux/hrtimer.h>
13#include <linux/jiffies.h>
14#include <linux/math64.h>
15#include <linux/timex.h>
16#include <linux/time.h>
17#include <linux/mm.h>
025b40ab 18#include <linux/module.h>
023f333a 19#include <linux/rtc.h>
7e8eda73 20#include <linux/audit.h>
4c7ee8de 21
aa6f9c59 22#include "ntp_internal.h"
0af86465
D
23#include "timekeeping_internal.h"
24
e2830b5c 25
b0ee7556 26/*
53bbfa9e 27 * NTP timekeeping variables:
a076b214
JS
28 *
29 * Note: All of the NTP state is protected by the timekeeping locks.
b0ee7556 30 */
b0ee7556 31
bd331268 32
53bbfa9e 33/* USER_HZ period (usecs): */
efefc977 34unsigned long tick_usec = USER_TICK_USEC;
53bbfa9e 35
02ab20ae 36/* SHIFTED_HZ period (nsecs): */
53bbfa9e 37unsigned long tick_nsec;
7dffa3c6 38
ea7cf49a 39static u64 tick_length;
53bbfa9e
IM
40static u64 tick_length_base;
41
90bf361c 42#define SECS_PER_DAY 86400
bbd12676 43#define MAX_TICKADJ 500LL /* usecs */
53bbfa9e 44#define MAX_TICKADJ_SCALED \
bbd12676 45 (((MAX_TICKADJ * NSEC_PER_USEC) << NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ)
d897a4ab 46#define MAX_TAI_OFFSET 100000
4c7ee8de
JS
47
48/*
49 * phase-lock loop variables
50 */
53bbfa9e
IM
51
52/*
53 * clock synchronization status
54 *
55 * (TIME_ERROR prevents overwriting the CMOS clock)
56 */
57static int time_state = TIME_OK;
58
59/* clock status bits: */
8357929e 60static int time_status = STA_UNSYNC;
53bbfa9e 61
53bbfa9e
IM
62/* time adjustment (nsecs): */
63static s64 time_offset;
64
65/* pll time constant: */
66static long time_constant = 2;
67
68/* maximum error (usecs): */
1f5b8f8a 69static long time_maxerror = NTP_PHASE_LIMIT;
53bbfa9e
IM
70
71/* estimated error (usecs): */
1f5b8f8a 72static long time_esterror = NTP_PHASE_LIMIT;
53bbfa9e
IM
73
74/* frequency offset (scaled nsecs/secs): */
75static s64 time_freq;
76
77/* time at last adjustment (secs): */
0af86465 78static time64_t time_reftime;
53bbfa9e 79
e1292ba1 80static long time_adjust;
53bbfa9e 81
069569e0
IM
82/* constant (boot-param configurable) NTP tick adjustment (upscaled) */
83static s64 ntp_tick_adj;
53bbfa9e 84
833f32d7
JS
85/* second value of the next pending leapsecond, or TIME64_MAX if no leap */
86static time64_t ntp_next_leap_sec = TIME64_MAX;
87
025b40ab
AG
88#ifdef CONFIG_NTP_PPS
89
90/*
91 * The following variables are used when a pulse-per-second (PPS) signal
92 * is available. They establish the engineering parameters of the clock
93 * discipline loop when controlled by the PPS signal.
94 */
95#define PPS_VALID 10 /* PPS signal watchdog max (s) */
96#define PPS_POPCORN 4 /* popcorn spike threshold (shift) */
97#define PPS_INTMIN 2 /* min freq interval (s) (shift) */
98#define PPS_INTMAX 8 /* max freq interval (s) (shift) */
99#define PPS_INTCOUNT 4 /* number of consecutive good intervals to
100 increase pps_shift or consecutive bad
101 intervals to decrease it */
102#define PPS_MAXWANDER 100000 /* max PPS freq wander (ns/s) */
103
104static int pps_valid; /* signal watchdog counter */
105static long pps_tf[3]; /* phase median filter */
106static long pps_jitter; /* current jitter (ns) */
7ec88e4b 107static struct timespec64 pps_fbase; /* beginning of the last freq interval */
025b40ab
AG
108static int pps_shift; /* current interval duration (s) (shift) */
109static int pps_intcnt; /* interval counter */
110static s64 pps_freq; /* frequency offset (scaled ns/s) */
111static long pps_stabil; /* current stability (scaled ns/s) */
112
113/*
114 * PPS signal quality monitors
115 */
116static long pps_calcnt; /* calibration intervals */
117static long pps_jitcnt; /* jitter limit exceeded */
118static long pps_stbcnt; /* stability limit exceeded */
119static long pps_errcnt; /* calibration errors */
120
121
122/* PPS kernel consumer compensates the whole phase error immediately.
123 * Otherwise, reduce the offset by a fixed factor times the time constant.
124 */
125static inline s64 ntp_offset_chunk(s64 offset)
126{
127 if (time_status & STA_PPSTIME && time_status & STA_PPSSIGNAL)
128 return offset;
129 else
130 return shift_right(offset, SHIFT_PLL + time_constant);
131}
132
133static inline void pps_reset_freq_interval(void)
134{
135 /* the PPS calibration interval may end
136 surprisingly early */
137 pps_shift = PPS_INTMIN;
138 pps_intcnt = 0;
139}
140
141/**
142 * pps_clear - Clears the PPS state variables
025b40ab
AG
143 */
144static inline void pps_clear(void)
145{
146 pps_reset_freq_interval();
147 pps_tf[0] = 0;
148 pps_tf[1] = 0;
149 pps_tf[2] = 0;
150 pps_fbase.tv_sec = pps_fbase.tv_nsec = 0;
151 pps_freq = 0;
152}
153
154/* Decrease pps_valid to indicate that another second has passed since
155 * the last PPS signal. When it reaches 0, indicate that PPS signal is
156 * missing.
025b40ab
AG
157 */
158static inline void pps_dec_valid(void)
159{
160 if (pps_valid > 0)
161 pps_valid--;
162 else {
163 time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER |
164 STA_PPSWANDER | STA_PPSERROR);
165 pps_clear();
166 }
167}
168
169static inline void pps_set_freq(s64 freq)
170{
171 pps_freq = freq;
172}
173
174static inline int is_error_status(int status)
175{
ea54bca3 176 return (status & (STA_UNSYNC|STA_CLOCKERR))
025b40ab
AG
177 /* PPS signal lost when either PPS time or
178 * PPS frequency synchronization requested
179 */
ea54bca3
GS
180 || ((status & (STA_PPSFREQ|STA_PPSTIME))
181 && !(status & STA_PPSSIGNAL))
025b40ab
AG
182 /* PPS jitter exceeded when
183 * PPS time synchronization requested */
ea54bca3 184 || ((status & (STA_PPSTIME|STA_PPSJITTER))
025b40ab
AG
185 == (STA_PPSTIME|STA_PPSJITTER))
186 /* PPS wander exceeded or calibration error when
187 * PPS frequency synchronization requested
188 */
ea54bca3
GS
189 || ((status & STA_PPSFREQ)
190 && (status & (STA_PPSWANDER|STA_PPSERROR)));
025b40ab
AG
191}
192
ead25417 193static inline void pps_fill_timex(struct __kernel_timex *txc)
025b40ab
AG
194{
195 txc->ppsfreq = shift_right((pps_freq >> PPM_SCALE_INV_SHIFT) *
196 PPM_SCALE_INV, NTP_SCALE_SHIFT);
197 txc->jitter = pps_jitter;
198 if (!(time_status & STA_NANO))
ead25417 199 txc->jitter = pps_jitter / NSEC_PER_USEC;
025b40ab
AG
200 txc->shift = pps_shift;
201 txc->stabil = pps_stabil;
202 txc->jitcnt = pps_jitcnt;
203 txc->calcnt = pps_calcnt;
204 txc->errcnt = pps_errcnt;
205 txc->stbcnt = pps_stbcnt;
206}
207
208#else /* !CONFIG_NTP_PPS */
209
210static inline s64 ntp_offset_chunk(s64 offset)
211{
212 return shift_right(offset, SHIFT_PLL + time_constant);
213}
214
215static inline void pps_reset_freq_interval(void) {}
216static inline void pps_clear(void) {}
217static inline void pps_dec_valid(void) {}
218static inline void pps_set_freq(s64 freq) {}
219
220static inline int is_error_status(int status)
221{
222 return status & (STA_UNSYNC|STA_CLOCKERR);
223}
224
ead25417 225static inline void pps_fill_timex(struct __kernel_timex *txc)
025b40ab
AG
226{
227 /* PPS is not implemented, so these are zero */
228 txc->ppsfreq = 0;
229 txc->jitter = 0;
230 txc->shift = 0;
231 txc->stabil = 0;
232 txc->jitcnt = 0;
233 txc->calcnt = 0;
234 txc->errcnt = 0;
235 txc->stbcnt = 0;
236}
237
238#endif /* CONFIG_NTP_PPS */
239
8357929e
JS
240
241/**
242 * ntp_synced - Returns 1 if the NTP status is not UNSYNC
243 *
244 */
245static inline int ntp_synced(void)
246{
247 return !(time_status & STA_UNSYNC);
248}
249
250
53bbfa9e
IM
251/*
252 * NTP methods:
253 */
4c7ee8de 254
9ce616aa
IM
255/*
256 * Update (tick_length, tick_length_base, tick_nsec), based
257 * on (tick_usec, ntp_tick_adj, time_freq):
258 */
70bc42f9
AB
259static void ntp_update_frequency(void)
260{
9ce616aa 261 u64 second_length;
bc26c31d 262 u64 new_base;
9ce616aa
IM
263
264 second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ)
265 << NTP_SCALE_SHIFT;
266
069569e0 267 second_length += ntp_tick_adj;
9ce616aa 268 second_length += time_freq;
70bc42f9 269
9ce616aa 270 tick_nsec = div_u64(second_length, HZ) >> NTP_SCALE_SHIFT;
bc26c31d 271 new_base = div_u64(second_length, NTP_INTERVAL_FREQ);
fdcedf7b
JS
272
273 /*
274 * Don't wait for the next second_overflow, apply
bc26c31d 275 * the change to the tick length immediately:
fdcedf7b 276 */
bc26c31d
IM
277 tick_length += new_base - tick_length_base;
278 tick_length_base = new_base;
70bc42f9
AB
279}
280
478b7aab 281static inline s64 ntp_update_offset_fll(s64 offset64, long secs)
f939890b
IM
282{
283 time_status &= ~STA_MODE;
284
285 if (secs < MINSEC)
478b7aab 286 return 0;
f939890b
IM
287
288 if (!(time_status & STA_FLL) && (secs <= MAXSEC))
478b7aab 289 return 0;
f939890b 290
f939890b
IM
291 time_status |= STA_MODE;
292
a078c6d0 293 return div64_long(offset64 << (NTP_SCALE_SHIFT - SHIFT_FLL), secs);
f939890b
IM
294}
295
ee9851b2
RZ
296static void ntp_update_offset(long offset)
297{
ee9851b2 298 s64 freq_adj;
f939890b
IM
299 s64 offset64;
300 long secs;
ee9851b2
RZ
301
302 if (!(time_status & STA_PLL))
303 return;
304
52d189f1
SL
305 if (!(time_status & STA_NANO)) {
306 /* Make sure the multiplication below won't overflow */
307 offset = clamp(offset, -USEC_PER_SEC, USEC_PER_SEC);
9f14f669 308 offset *= NSEC_PER_USEC;
52d189f1 309 }
ee9851b2
RZ
310
311 /*
312 * Scale the phase adjustment and
313 * clamp to the operating range.
314 */
52d189f1 315 offset = clamp(offset, -MAXPHASE, MAXPHASE);
ee9851b2
RZ
316
317 /*
318 * Select how the frequency is to be controlled
319 * and in which mode (PLL or FLL).
320 */
0af86465 321 secs = (long)(__ktime_get_real_seconds() - time_reftime);
10dd31a7 322 if (unlikely(time_status & STA_FREQHOLD))
c7986acb
IM
323 secs = 0;
324
0af86465 325 time_reftime = __ktime_get_real_seconds();
ee9851b2 326
f939890b 327 offset64 = offset;
8af3c153 328 freq_adj = ntp_update_offset_fll(offset64, secs);
f939890b 329
8af3c153
ML
330 /*
331 * Clamp update interval to reduce PLL gain with low
332 * sampling rate (e.g. intermittent network connection)
333 * to avoid instability.
334 */
335 if (unlikely(secs > 1 << (SHIFT_PLL + 1 + time_constant)))
336 secs = 1 << (SHIFT_PLL + 1 + time_constant);
337
338 freq_adj += (offset64 * secs) <<
339 (NTP_SCALE_SHIFT - 2 * (SHIFT_PLL + 2 + time_constant));
f939890b
IM
340
341 freq_adj = min(freq_adj + time_freq, MAXFREQ_SCALED);
342
343 time_freq = max(freq_adj, -MAXFREQ_SCALED);
344
345 time_offset = div_s64(offset64 << NTP_SCALE_SHIFT, NTP_INTERVAL_FREQ);
ee9851b2
RZ
346}
347
b0ee7556
RZ
348/**
349 * ntp_clear - Clears the NTP state variables
b0ee7556
RZ
350 */
351void ntp_clear(void)
352{
53bbfa9e
IM
353 time_adjust = 0; /* stop active adjtime() */
354 time_status |= STA_UNSYNC;
355 time_maxerror = NTP_PHASE_LIMIT;
356 time_esterror = NTP_PHASE_LIMIT;
b0ee7556
RZ
357
358 ntp_update_frequency();
359
53bbfa9e
IM
360 tick_length = tick_length_base;
361 time_offset = 0;
025b40ab 362
833f32d7 363 ntp_next_leap_sec = TIME64_MAX;
025b40ab
AG
364 /* Clear PPS state variables */
365 pps_clear();
b0ee7556
RZ
366}
367
ea7cf49a
JS
368
369u64 ntp_tick_length(void)
370{
a076b214 371 return tick_length;
ea7cf49a
JS
372}
373
833f32d7
JS
374/**
375 * ntp_get_next_leap - Returns the next leapsecond in CLOCK_REALTIME ktime_t
376 *
377 * Provides the time of the next leapsecond against CLOCK_REALTIME in
378 * a ktime_t format. Returns KTIME_MAX if no leapsecond is pending.
379 */
380ktime_t ntp_get_next_leap(void)
381{
382 ktime_t ret;
383
384 if ((time_state == TIME_INS) && (time_status & STA_INS))
385 return ktime_set(ntp_next_leap_sec, 0);
2456e855 386 ret = KTIME_MAX;
833f32d7
JS
387 return ret;
388}
ea7cf49a 389
4c7ee8de 390/*
6b43ae8a
JS
391 * this routine handles the overflow of the microsecond field
392 *
393 * The tricky bits of code to handle the accurate clock support
394 * were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame.
395 * They were originally developed for SUN and DEC kernels.
396 * All the kudos should go to Dave for this stuff.
397 *
398 * Also handles leap second processing, and returns leap offset
4c7ee8de 399 */
c7963487 400int second_overflow(time64_t secs)
4c7ee8de 401{
6b43ae8a 402 s64 delta;
bd331268 403 int leap = 0;
c7963487 404 s32 rem;
6b43ae8a
JS
405
406 /*
407 * Leap second processing. If in leap-insert state at the end of the
408 * day, the system clock is set back one second; if in leap-delete
409 * state, the system clock is set ahead one second.
410 */
4c7ee8de
JS
411 switch (time_state) {
412 case TIME_OK:
833f32d7 413 if (time_status & STA_INS) {
6b43ae8a 414 time_state = TIME_INS;
c7963487
D
415 div_s64_rem(secs, SECS_PER_DAY, &rem);
416 ntp_next_leap_sec = secs + SECS_PER_DAY - rem;
833f32d7 417 } else if (time_status & STA_DEL) {
6b43ae8a 418 time_state = TIME_DEL;
c7963487
D
419 div_s64_rem(secs + 1, SECS_PER_DAY, &rem);
420 ntp_next_leap_sec = secs + SECS_PER_DAY - rem;
833f32d7 421 }
4c7ee8de
JS
422 break;
423 case TIME_INS:
833f32d7
JS
424 if (!(time_status & STA_INS)) {
425 ntp_next_leap_sec = TIME64_MAX;
6b1859db 426 time_state = TIME_OK;
c7963487 427 } else if (secs == ntp_next_leap_sec) {
6b43ae8a
JS
428 leap = -1;
429 time_state = TIME_OOP;
430 printk(KERN_NOTICE
431 "Clock: inserting leap second 23:59:60 UTC\n");
432 }
4c7ee8de
JS
433 break;
434 case TIME_DEL:
833f32d7
JS
435 if (!(time_status & STA_DEL)) {
436 ntp_next_leap_sec = TIME64_MAX;
6b1859db 437 time_state = TIME_OK;
c7963487 438 } else if (secs == ntp_next_leap_sec) {
6b43ae8a 439 leap = 1;
833f32d7 440 ntp_next_leap_sec = TIME64_MAX;
6b43ae8a
JS
441 time_state = TIME_WAIT;
442 printk(KERN_NOTICE
443 "Clock: deleting leap second 23:59:59 UTC\n");
444 }
4c7ee8de
JS
445 break;
446 case TIME_OOP:
833f32d7 447 ntp_next_leap_sec = TIME64_MAX;
4c7ee8de 448 time_state = TIME_WAIT;
6b43ae8a 449 break;
4c7ee8de
JS
450 case TIME_WAIT:
451 if (!(time_status & (STA_INS | STA_DEL)))
ee9851b2 452 time_state = TIME_OK;
7dffa3c6
RZ
453 break;
454 }
bd331268 455
7dffa3c6
RZ
456
457 /* Bump the maxerror field */
458 time_maxerror += MAXFREQ / NSEC_PER_USEC;
459 if (time_maxerror > NTP_PHASE_LIMIT) {
460 time_maxerror = NTP_PHASE_LIMIT;
461 time_status |= STA_UNSYNC;
4c7ee8de
JS
462 }
463
025b40ab 464 /* Compute the phase adjustment for the next second */
39854fe8
IM
465 tick_length = tick_length_base;
466
025b40ab 467 delta = ntp_offset_chunk(time_offset);
39854fe8
IM
468 time_offset -= delta;
469 tick_length += delta;
4c7ee8de 470
025b40ab
AG
471 /* Check PPS signal */
472 pps_dec_valid();
473
3c972c24 474 if (!time_adjust)
bd331268 475 goto out;
3c972c24
IM
476
477 if (time_adjust > MAX_TICKADJ) {
478 time_adjust -= MAX_TICKADJ;
479 tick_length += MAX_TICKADJ_SCALED;
bd331268 480 goto out;
4c7ee8de 481 }
3c972c24
IM
482
483 if (time_adjust < -MAX_TICKADJ) {
484 time_adjust += MAX_TICKADJ;
485 tick_length -= MAX_TICKADJ_SCALED;
bd331268 486 goto out;
3c972c24
IM
487 }
488
489 tick_length += (s64)(time_adjust * NSEC_PER_USEC / NTP_INTERVAL_FREQ)
490 << NTP_SCALE_SHIFT;
491 time_adjust = 0;
6b43ae8a 492
bd331268 493out:
6b43ae8a 494 return leap;
4c7ee8de
JS
495}
496
0f295b06
JG
497static void sync_hw_clock(struct work_struct *work);
498static DECLARE_DELAYED_WORK(sync_work, sync_hw_clock);
499
500static void sched_sync_hw_clock(struct timespec64 now,
501 unsigned long target_nsec, bool fail)
502
503{
504 struct timespec64 next;
505
d30faff9 506 ktime_get_real_ts64(&next);
0f295b06
JG
507 if (!fail)
508 next.tv_sec = 659;
509 else {
510 /*
511 * Try again as soon as possible. Delaying long periods
512 * decreases the accuracy of the work queue timer. Due to this
513 * the algorithm is very likely to require a short-sleep retry
514 * after the above long sleep to synchronize ts_nsec.
515 */
516 next.tv_sec = 0;
517 }
518
519 /* Compute the needed delay that will get to tv_nsec == target_nsec */
520 next.tv_nsec = target_nsec - next.tv_nsec;
521 if (next.tv_nsec <= 0)
522 next.tv_nsec += NSEC_PER_SEC;
523 if (next.tv_nsec >= NSEC_PER_SEC) {
524 next.tv_sec++;
525 next.tv_nsec -= NSEC_PER_SEC;
526 }
527
528 queue_delayed_work(system_power_efficient_wq, &sync_work,
529 timespec64_to_jiffies(&next));
530}
531
532static void sync_rtc_clock(void)
533{
534 unsigned long target_nsec;
535 struct timespec64 adjust, now;
536 int rc;
537
538 if (!IS_ENABLED(CONFIG_RTC_SYSTOHC))
539 return;
540
d30faff9 541 ktime_get_real_ts64(&now);
0f295b06
JG
542
543 adjust = now;
544 if (persistent_clock_is_local)
545 adjust.tv_sec -= (sys_tz.tz_minuteswest * 60);
546
547 /*
548 * The current RTC in use will provide the target_nsec it wants to be
549 * called at, and does rtc_tv_nsec_ok internally.
550 */
551 rc = rtc_set_ntp_time(adjust, &target_nsec);
552 if (rc == -ENODEV)
553 return;
554
555 sched_sync_hw_clock(now, target_nsec, rc);
556}
557
3c00a1fe
XP
558#ifdef CONFIG_GENERIC_CMOS_UPDATE
559int __weak update_persistent_clock64(struct timespec64 now64)
560{
92661788 561 return -ENODEV;
3c00a1fe
XP
562}
563#endif
564
0f295b06 565static bool sync_cmos_clock(void)
82644459 566{
0f295b06 567 static bool no_cmos;
d6d29896 568 struct timespec64 now;
0f295b06
JG
569 struct timespec64 adjust;
570 int rc = -EPROTO;
571 long target_nsec = NSEC_PER_SEC / 2;
572
573 if (!IS_ENABLED(CONFIG_GENERIC_CMOS_UPDATE))
574 return false;
575
576 if (no_cmos)
577 return false;
82644459
TG
578
579 /*
0f295b06
JG
580 * Historically update_persistent_clock64() has followed x86
581 * semantics, which match the MC146818A/etc RTC. This RTC will store
582 * 'adjust' and then in .5s it will advance once second.
583 *
584 * Architectures are strongly encouraged to use rtclib and not
585 * implement this legacy API.
82644459 586 */
d30faff9 587 ktime_get_real_ts64(&now);
0f295b06 588 if (rtc_tv_nsec_ok(-1 * target_nsec, &adjust, &now)) {
84e345e4
PB
589 if (persistent_clock_is_local)
590 adjust.tv_sec -= (sys_tz.tz_minuteswest * 60);
0f295b06
JG
591 rc = update_persistent_clock64(adjust);
592 /*
593 * The machine does not support update_persistent_clock64 even
594 * though it defines CONFIG_GENERIC_CMOS_UPDATE.
595 */
596 if (rc == -ENODEV) {
597 no_cmos = true;
598 return false;
599 }
023f333a 600 }
82644459 601
0f295b06
JG
602 sched_sync_hw_clock(now, target_nsec, rc);
603 return true;
604}
82644459 605
0f295b06
JG
606/*
607 * If we have an externally synchronized Linux clock, then update RTC clock
608 * accordingly every ~11 minutes. Generally RTCs can only store second
609 * precision, but many RTCs will adjust the phase of their second tick to
610 * match the moment of update. This infrastructure arranges to call to the RTC
611 * set at the correct moment to phase synchronize the RTC second tick over
612 * with the kernel clock.
613 */
614static void sync_hw_clock(struct work_struct *work)
615{
616 if (!ntp_synced())
617 return;
82644459 618
0f295b06
JG
619 if (sync_cmos_clock())
620 return;
621
622 sync_rtc_clock();
82644459
TG
623}
624
7bd36014 625void ntp_notify_cmos_timer(void)
4c7ee8de 626{
0f295b06
JG
627 if (!ntp_synced())
628 return;
82644459 629
0f295b06
JG
630 if (IS_ENABLED(CONFIG_GENERIC_CMOS_UPDATE) ||
631 IS_ENABLED(CONFIG_RTC_SYSTOHC))
632 queue_delayed_work(system_power_efficient_wq, &sync_work, 0);
633}
80f22571
IM
634
635/*
636 * Propagate a new txc->status value into the NTP state:
637 */
ead25417 638static inline void process_adj_status(const struct __kernel_timex *txc)
80f22571 639{
80f22571
IM
640 if ((time_status & STA_PLL) && !(txc->status & STA_PLL)) {
641 time_state = TIME_OK;
642 time_status = STA_UNSYNC;
833f32d7 643 ntp_next_leap_sec = TIME64_MAX;
025b40ab
AG
644 /* restart PPS frequency calibration */
645 pps_reset_freq_interval();
80f22571 646 }
80f22571
IM
647
648 /*
649 * If we turn on PLL adjustments then reset the
650 * reference time to current time.
651 */
652 if (!(time_status & STA_PLL) && (txc->status & STA_PLL))
0af86465 653 time_reftime = __ktime_get_real_seconds();
80f22571 654
a2a5ac86
JS
655 /* only set allowed bits */
656 time_status &= STA_RONLY;
80f22571 657 time_status |= txc->status & ~STA_RONLY;
80f22571 658}
cd5398be 659
a076b214 660
ead25417
DD
661static inline void process_adjtimex_modes(const struct __kernel_timex *txc,
662 s32 *time_tai)
80f22571
IM
663{
664 if (txc->modes & ADJ_STATUS)
0f9987b6 665 process_adj_status(txc);
80f22571
IM
666
667 if (txc->modes & ADJ_NANO)
668 time_status |= STA_NANO;
e9629165 669
80f22571
IM
670 if (txc->modes & ADJ_MICRO)
671 time_status &= ~STA_NANO;
672
673 if (txc->modes & ADJ_FREQUENCY) {
2b9d1496 674 time_freq = txc->freq * PPM_SCALE;
80f22571
IM
675 time_freq = min(time_freq, MAXFREQ_SCALED);
676 time_freq = max(time_freq, -MAXFREQ_SCALED);
025b40ab
AG
677 /* update pps_freq */
678 pps_set_freq(time_freq);
80f22571
IM
679 }
680
681 if (txc->modes & ADJ_MAXERROR)
682 time_maxerror = txc->maxerror;
e9629165 683
80f22571
IM
684 if (txc->modes & ADJ_ESTERROR)
685 time_esterror = txc->esterror;
686
687 if (txc->modes & ADJ_TIMECONST) {
688 time_constant = txc->constant;
689 if (!(time_status & STA_NANO))
690 time_constant += 4;
691 time_constant = min(time_constant, (long)MAXTC);
692 time_constant = max(time_constant, 0l);
693 }
694
d897a4ab
ML
695 if (txc->modes & ADJ_TAI &&
696 txc->constant >= 0 && txc->constant <= MAX_TAI_OFFSET)
cc244dda 697 *time_tai = txc->constant;
80f22571
IM
698
699 if (txc->modes & ADJ_OFFSET)
700 ntp_update_offset(txc->offset);
e9629165 701
80f22571
IM
702 if (txc->modes & ADJ_TICK)
703 tick_usec = txc->tick;
704
705 if (txc->modes & (ADJ_TICK|ADJ_FREQUENCY|ADJ_OFFSET))
706 ntp_update_frequency();
707}
708
ad460967 709
ad460967
JS
710/*
711 * adjtimex mainly allows reading (and writing, if superuser) of
712 * kernel time-keeping variables. used by xntpd.
713 */
ead25417 714int __do_adjtimex(struct __kernel_timex *txc, const struct timespec64 *ts,
7e8eda73 715 s32 *time_tai, struct audit_ntp_data *ad)
ad460967 716{
ad460967
JS
717 int result;
718
916c7a85
RZ
719 if (txc->modes & ADJ_ADJTIME) {
720 long save_adjust = time_adjust;
721
722 if (!(txc->modes & ADJ_OFFSET_READONLY)) {
723 /* adjtime() is independent from ntp_adjtime() */
724 time_adjust = txc->offset;
725 ntp_update_frequency();
7e8eda73
OM
726
727 audit_ntp_set_old(ad, AUDIT_NTP_ADJUST, save_adjust);
728 audit_ntp_set_new(ad, AUDIT_NTP_ADJUST, time_adjust);
916c7a85
RZ
729 }
730 txc->offset = save_adjust;
e9629165 731 } else {
e9629165 732 /* If there are input parameters, then process them: */
7e8eda73
OM
733 if (txc->modes) {
734 audit_ntp_set_old(ad, AUDIT_NTP_OFFSET, time_offset);
735 audit_ntp_set_old(ad, AUDIT_NTP_FREQ, time_freq);
736 audit_ntp_set_old(ad, AUDIT_NTP_STATUS, time_status);
737 audit_ntp_set_old(ad, AUDIT_NTP_TAI, *time_tai);
738 audit_ntp_set_old(ad, AUDIT_NTP_TICK, tick_usec);
739
0f9987b6 740 process_adjtimex_modes(txc, time_tai);
eea83d89 741
7e8eda73
OM
742 audit_ntp_set_new(ad, AUDIT_NTP_OFFSET, time_offset);
743 audit_ntp_set_new(ad, AUDIT_NTP_FREQ, time_freq);
744 audit_ntp_set_new(ad, AUDIT_NTP_STATUS, time_status);
745 audit_ntp_set_new(ad, AUDIT_NTP_TAI, *time_tai);
746 audit_ntp_set_new(ad, AUDIT_NTP_TICK, tick_usec);
747 }
748
e9629165 749 txc->offset = shift_right(time_offset * NTP_INTERVAL_FREQ,
916c7a85 750 NTP_SCALE_SHIFT);
e9629165 751 if (!(time_status & STA_NANO))
ead25417 752 txc->offset = (u32)txc->offset / NSEC_PER_USEC;
e9629165 753 }
916c7a85 754
eea83d89 755 result = time_state; /* mostly `TIME_OK' */
025b40ab
AG
756 /* check for errors */
757 if (is_error_status(time_status))
4c7ee8de
JS
758 result = TIME_ERROR;
759
d40e944c 760 txc->freq = shift_right((time_freq >> PPM_SCALE_INV_SHIFT) *
2b9d1496 761 PPM_SCALE_INV, NTP_SCALE_SHIFT);
4c7ee8de
JS
762 txc->maxerror = time_maxerror;
763 txc->esterror = time_esterror;
764 txc->status = time_status;
765 txc->constant = time_constant;
70bc42f9 766 txc->precision = 1;
074b3b87 767 txc->tolerance = MAXFREQ_SCALED / PPM_SCALE;
4c7ee8de 768 txc->tick = tick_usec;
87ace39b 769 txc->tai = *time_tai;
4c7ee8de 770
025b40ab
AG
771 /* fill PPS status fields */
772 pps_fill_timex(txc);
e9629165 773
2f584134 774 txc->time.tv_sec = ts->tv_sec;
87ace39b 775 txc->time.tv_usec = ts->tv_nsec;
eea83d89 776 if (!(time_status & STA_NANO))
ead25417 777 txc->time.tv_usec = ts->tv_nsec / NSEC_PER_USEC;
ee9851b2 778
96efdcf2
JS
779 /* Handle leapsec adjustments */
780 if (unlikely(ts->tv_sec >= ntp_next_leap_sec)) {
781 if ((time_state == TIME_INS) && (time_status & STA_INS)) {
782 result = TIME_OOP;
783 txc->tai++;
784 txc->time.tv_sec--;
785 }
786 if ((time_state == TIME_DEL) && (time_status & STA_DEL)) {
787 result = TIME_WAIT;
788 txc->tai--;
789 txc->time.tv_sec++;
790 }
791 if ((time_state == TIME_OOP) &&
792 (ts->tv_sec == ntp_next_leap_sec)) {
793 result = TIME_WAIT;
794 }
795 }
796
ee9851b2 797 return result;
4c7ee8de 798}
10a398d0 799
025b40ab
AG
800#ifdef CONFIG_NTP_PPS
801
802/* actually struct pps_normtime is good old struct timespec, but it is
803 * semantically different (and it is the reason why it was invented):
804 * pps_normtime.nsec has a range of ( -NSEC_PER_SEC / 2, NSEC_PER_SEC / 2 ]
805 * while timespec.tv_nsec has a range of [0, NSEC_PER_SEC) */
806struct pps_normtime {
7ec88e4b 807 s64 sec; /* seconds */
025b40ab
AG
808 long nsec; /* nanoseconds */
809};
810
811/* normalize the timestamp so that nsec is in the
812 ( -NSEC_PER_SEC / 2, NSEC_PER_SEC / 2 ] interval */
7ec88e4b 813static inline struct pps_normtime pps_normalize_ts(struct timespec64 ts)
025b40ab
AG
814{
815 struct pps_normtime norm = {
816 .sec = ts.tv_sec,
817 .nsec = ts.tv_nsec
818 };
819
820 if (norm.nsec > (NSEC_PER_SEC >> 1)) {
821 norm.nsec -= NSEC_PER_SEC;
822 norm.sec++;
823 }
824
825 return norm;
826}
827
828/* get current phase correction and jitter */
829static inline long pps_phase_filter_get(long *jitter)
830{
831 *jitter = pps_tf[0] - pps_tf[1];
832 if (*jitter < 0)
833 *jitter = -*jitter;
834
835 /* TODO: test various filters */
836 return pps_tf[0];
837}
838
839/* add the sample to the phase filter */
840static inline void pps_phase_filter_add(long err)
841{
842 pps_tf[2] = pps_tf[1];
843 pps_tf[1] = pps_tf[0];
844 pps_tf[0] = err;
845}
846
847/* decrease frequency calibration interval length.
848 * It is halved after four consecutive unstable intervals.
849 */
850static inline void pps_dec_freq_interval(void)
851{
852 if (--pps_intcnt <= -PPS_INTCOUNT) {
853 pps_intcnt = -PPS_INTCOUNT;
854 if (pps_shift > PPS_INTMIN) {
855 pps_shift--;
856 pps_intcnt = 0;
857 }
858 }
859}
860
861/* increase frequency calibration interval length.
862 * It is doubled after four consecutive stable intervals.
863 */
864static inline void pps_inc_freq_interval(void)
865{
866 if (++pps_intcnt >= PPS_INTCOUNT) {
867 pps_intcnt = PPS_INTCOUNT;
868 if (pps_shift < PPS_INTMAX) {
869 pps_shift++;
870 pps_intcnt = 0;
871 }
872 }
873}
874
875/* update clock frequency based on MONOTONIC_RAW clock PPS signal
876 * timestamps
877 *
878 * At the end of the calibration interval the difference between the
879 * first and last MONOTONIC_RAW clock timestamps divided by the length
880 * of the interval becomes the frequency update. If the interval was
881 * too long, the data are discarded.
882 * Returns the difference between old and new frequency values.
883 */
884static long hardpps_update_freq(struct pps_normtime freq_norm)
885{
886 long delta, delta_mod;
887 s64 ftemp;
888
889 /* check if the frequency interval was too long */
890 if (freq_norm.sec > (2 << pps_shift)) {
891 time_status |= STA_PPSERROR;
892 pps_errcnt++;
893 pps_dec_freq_interval();
6d9bcb62 894 printk_deferred(KERN_ERR
7ec88e4b 895 "hardpps: PPSERROR: interval too long - %lld s\n",
6d9bcb62 896 freq_norm.sec);
025b40ab
AG
897 return 0;
898 }
899
900 /* here the raw frequency offset and wander (stability) is
901 * calculated. If the wander is less than the wander threshold
902 * the interval is increased; otherwise it is decreased.
903 */
904 ftemp = div_s64(((s64)(-freq_norm.nsec)) << NTP_SCALE_SHIFT,
905 freq_norm.sec);
906 delta = shift_right(ftemp - pps_freq, NTP_SCALE_SHIFT);
907 pps_freq = ftemp;
908 if (delta > PPS_MAXWANDER || delta < -PPS_MAXWANDER) {
6d9bcb62
JS
909 printk_deferred(KERN_WARNING
910 "hardpps: PPSWANDER: change=%ld\n", delta);
025b40ab
AG
911 time_status |= STA_PPSWANDER;
912 pps_stbcnt++;
913 pps_dec_freq_interval();
914 } else { /* good sample */
915 pps_inc_freq_interval();
916 }
917
918 /* the stability metric is calculated as the average of recent
919 * frequency changes, but is used only for performance
920 * monitoring
921 */
922 delta_mod = delta;
923 if (delta_mod < 0)
924 delta_mod = -delta_mod;
925 pps_stabil += (div_s64(((s64)delta_mod) <<
926 (NTP_SCALE_SHIFT - SHIFT_USEC),
927 NSEC_PER_USEC) - pps_stabil) >> PPS_INTMIN;
928
929 /* if enabled, the system clock frequency is updated */
930 if ((time_status & STA_PPSFREQ) != 0 &&
931 (time_status & STA_FREQHOLD) == 0) {
932 time_freq = pps_freq;
933 ntp_update_frequency();
934 }
935
936 return delta;
937}
938
939/* correct REALTIME clock phase error against PPS signal */
940static void hardpps_update_phase(long error)
941{
942 long correction = -error;
943 long jitter;
944
945 /* add the sample to the median filter */
946 pps_phase_filter_add(correction);
947 correction = pps_phase_filter_get(&jitter);
948
949 /* Nominal jitter is due to PPS signal noise. If it exceeds the
950 * threshold, the sample is discarded; otherwise, if so enabled,
951 * the time offset is updated.
952 */
953 if (jitter > (pps_jitter << PPS_POPCORN)) {
6d9bcb62
JS
954 printk_deferred(KERN_WARNING
955 "hardpps: PPSJITTER: jitter=%ld, limit=%ld\n",
956 jitter, (pps_jitter << PPS_POPCORN));
025b40ab
AG
957 time_status |= STA_PPSJITTER;
958 pps_jitcnt++;
959 } else if (time_status & STA_PPSTIME) {
960 /* correct the time using the phase offset */
961 time_offset = div_s64(((s64)correction) << NTP_SCALE_SHIFT,
962 NTP_INTERVAL_FREQ);
963 /* cancel running adjtime() */
964 time_adjust = 0;
965 }
966 /* update jitter */
967 pps_jitter += (jitter - pps_jitter) >> PPS_INTMIN;
968}
969
970/*
aa6f9c59 971 * __hardpps() - discipline CPU clock oscillator to external PPS signal
025b40ab
AG
972 *
973 * This routine is called at each PPS signal arrival in order to
974 * discipline the CPU clock oscillator to the PPS signal. It takes two
975 * parameters: REALTIME and MONOTONIC_RAW clock timestamps. The former
976 * is used to correct clock phase error and the latter is used to
977 * correct the frequency.
978 *
979 * This code is based on David Mills's reference nanokernel
980 * implementation. It was mostly rewritten but keeps the same idea.
981 */
7ec88e4b 982void __hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_ts)
025b40ab
AG
983{
984 struct pps_normtime pts_norm, freq_norm;
025b40ab
AG
985
986 pts_norm = pps_normalize_ts(*phase_ts);
987
025b40ab
AG
988 /* clear the error bits, they will be set again if needed */
989 time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR);
990
991 /* indicate signal presence */
992 time_status |= STA_PPSSIGNAL;
993 pps_valid = PPS_VALID;
994
995 /* when called for the first time,
996 * just start the frequency interval */
997 if (unlikely(pps_fbase.tv_sec == 0)) {
998 pps_fbase = *raw_ts;
025b40ab
AG
999 return;
1000 }
1001
1002 /* ok, now we have a base for frequency calculation */
7ec88e4b 1003 freq_norm = pps_normalize_ts(timespec64_sub(*raw_ts, pps_fbase));
025b40ab
AG
1004
1005 /* check that the signal is in the range
1006 * [1s - MAXFREQ us, 1s + MAXFREQ us], otherwise reject it */
1007 if ((freq_norm.sec == 0) ||
1008 (freq_norm.nsec > MAXFREQ * freq_norm.sec) ||
1009 (freq_norm.nsec < -MAXFREQ * freq_norm.sec)) {
1010 time_status |= STA_PPSJITTER;
1011 /* restart the frequency calibration interval */
1012 pps_fbase = *raw_ts;
6d9bcb62 1013 printk_deferred(KERN_ERR "hardpps: PPSJITTER: bad pulse\n");
025b40ab
AG
1014 return;
1015 }
1016
1017 /* signal is ok */
1018
1019 /* check if the current frequency interval is finished */
1020 if (freq_norm.sec >= (1 << pps_shift)) {
1021 pps_calcnt++;
1022 /* restart the frequency calibration interval */
1023 pps_fbase = *raw_ts;
1024 hardpps_update_freq(freq_norm);
1025 }
1026
1027 hardpps_update_phase(pts_norm.nsec);
1028
025b40ab 1029}
025b40ab
AG
1030#endif /* CONFIG_NTP_PPS */
1031
10a398d0
RZ
1032static int __init ntp_tick_adj_setup(char *str)
1033{
86b2dcd4 1034 int rc = kstrtos64(str, 0, &ntp_tick_adj);
cdafb93f
FF
1035 if (rc)
1036 return rc;
069569e0 1037
86b2dcd4 1038 ntp_tick_adj <<= NTP_SCALE_SHIFT;
10a398d0
RZ
1039 return 1;
1040}
1041
1042__setup("ntp_tick_adj=", ntp_tick_adj_setup);
7dffa3c6
RZ
1043
1044void __init ntp_init(void)
1045{
1046 ntp_clear();
7dffa3c6 1047}