Annotation of src/sys/kern/kern_ntptime.c, Revision 1.57.18.1
1.57.18.1! christos 1: /* $NetBSD: kern_ntptime.c,v 1.60 2018/10/29 22:02:25 christos Exp $ */
1.48 ad 2:
3: /*-
4: * Copyright (c) 2008 The NetBSD Foundation, Inc.
5: * All rights reserved.
6: *
7: * Redistribution and use in source and binary forms, with or without
8: * modification, are permitted provided that the following conditions
9: * are met:
10: * 1. Redistributions of source code must retain the above copyright
11: * notice, this list of conditions and the following disclaimer.
12: * 2. Redistributions in binary form must reproduce the above copyright
13: * notice, this list of conditions and the following disclaimer in the
14: * documentation and/or other materials provided with the distribution.
15: *
16: * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
17: * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
18: * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19: * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
20: * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21: * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22: * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23: * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24: * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25: * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26: * POSSIBILITY OF SUCH DAMAGE.
27: */
1.33 kardel 28:
29: /*-
30: ***********************************************************************
31: * *
32: * Copyright (c) David L. Mills 1993-2001 *
33: * *
34: * Permission to use, copy, modify, and distribute this software and *
35: * its documentation for any purpose and without fee is hereby *
36: * granted, provided that the above copyright notice appears in all *
37: * copies and that both the copyright notice and this permission *
38: * notice appear in supporting documentation, and that the name *
39: * University of Delaware not be used in advertising or publicity *
40: * pertaining to distribution of the software without specific, *
41: * written prior permission. The University of Delaware makes no *
42: * representations about the suitability this software for any *
43: * purpose. It is provided "as is" without express or implied *
44: * warranty. *
45: * *
46: **********************************************************************/
1.1 jonathan 47:
1.33 kardel 48: /*
49: * Adapted from the original sources for FreeBSD and timecounters by:
50: * Poul-Henning Kamp <phk@FreeBSD.org>.
51: *
52: * The 32bit version of the "LP" macros seems a bit past its "sell by"
53: * date so I have retained only the 64bit version and included it directly
54: * in this file.
55: *
56: * Only minor changes done to interface with the timecounters over in
57: * sys/kern/kern_clock.c. Some of the comments below may be (even more)
58: * confusing and/or plain wrong in that context.
59: */
60:
61: #include <sys/cdefs.h>
62: /* __FBSDID("$FreeBSD: src/sys/kern/kern_ntptime.c,v 1.59 2005/05/28 14:34:41 rwatson Exp $"); */
1.57.18.1! christos 63: __KERNEL_RCSID(0, "$NetBSD: kern_ntptime.c,v 1.60 2018/10/29 22:02:25 christos Exp $");
1.33 kardel 64:
1.54 pooka 65: #ifdef _KERNEL_OPT
1.33 kardel 66: #include "opt_ntp.h"
1.54 pooka 67: #endif
1.33 kardel 68:
69: #include <sys/param.h>
70: #include <sys/resourcevar.h>
71: #include <sys/systm.h>
72: #include <sys/kernel.h>
73: #include <sys/proc.h>
74: #include <sys/sysctl.h>
75: #include <sys/timex.h>
76: #include <sys/vnode.h>
77: #include <sys/kauth.h>
78: #include <sys/mount.h>
79: #include <sys/syscallargs.h>
1.48 ad 80: #include <sys/cpu.h>
1.33 kardel 81:
1.48 ad 82: #include <compat/sys/timex.h>
1.33 kardel 83:
84: /*
85: * Single-precision macros for 64-bit machines
86: */
87: typedef int64_t l_fp;
88: #define L_ADD(v, u) ((v) += (u))
89: #define L_SUB(v, u) ((v) -= (u))
90: #define L_ADDHI(v, a) ((v) += (int64_t)(a) << 32)
91: #define L_NEG(v) ((v) = -(v))
92: #define L_RSHIFT(v, n) \
93: do { \
94: if ((v) < 0) \
95: (v) = -(-(v) >> (n)); \
96: else \
97: (v) = (v) >> (n); \
98: } while (0)
99: #define L_MPY(v, a) ((v) *= (a))
100: #define L_CLR(v) ((v) = 0)
101: #define L_ISNEG(v) ((v) < 0)
1.57 joerg 102: #define L_LINT(v, a) ((v) = (int64_t)((uint64_t)(a) << 32))
1.33 kardel 103: #define L_GINT(v) ((v) < 0 ? -(-(v) >> 32) : (v) >> 32)
104:
105: #ifdef NTP
106: /*
107: * Generic NTP kernel interface
108: *
109: * These routines constitute the Network Time Protocol (NTP) interfaces
110: * for user and daemon application programs. The ntp_gettime() routine
111: * provides the time, maximum error (synch distance) and estimated error
112: * (dispersion) to client user application programs. The ntp_adjtime()
113: * routine is used by the NTP daemon to adjust the system clock to an
114: * externally derived time. The time offset and related variables set by
115: * this routine are used by other routines in this module to adjust the
116: * phase and frequency of the clock discipline loop which controls the
117: * system clock.
118: *
119: * When the kernel time is reckoned directly in nanoseconds (NTP_NANO
120: * defined), the time at each tick interrupt is derived directly from
121: * the kernel time variable. When the kernel time is reckoned in
122: * microseconds, (NTP_NANO undefined), the time is derived from the
123: * kernel time variable together with a variable representing the
124: * leftover nanoseconds at the last tick interrupt. In either case, the
125: * current nanosecond time is reckoned from these values plus an
126: * interpolated value derived by the clock routines in another
127: * architecture-specific module. The interpolation can use either a
128: * dedicated counter or a processor cycle counter (PCC) implemented in
129: * some architectures.
130: *
131: * Note that all routines must run at priority splclock or higher.
132: */
133: /*
134: * Phase/frequency-lock loop (PLL/FLL) definitions
135: *
136: * The nanosecond clock discipline uses two variable types, time
137: * variables and frequency variables. Both types are represented as 64-
138: * bit fixed-point quantities with the decimal point between two 32-bit
139: * halves. On a 32-bit machine, each half is represented as a single
140: * word and mathematical operations are done using multiple-precision
141: * arithmetic. On a 64-bit machine, ordinary computer arithmetic is
142: * used.
143: *
144: * A time variable is a signed 64-bit fixed-point number in ns and
145: * fraction. It represents the remaining time offset to be amortized
146: * over succeeding tick interrupts. The maximum time offset is about
147: * 0.5 s and the resolution is about 2.3e-10 ns.
148: *
149: * 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
150: * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
151: * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
152: * |s s s| ns |
153: * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
154: * | fraction |
155: * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
156: *
157: * A frequency variable is a signed 64-bit fixed-point number in ns/s
158: * and fraction. It represents the ns and fraction to be added to the
159: * kernel time variable at each second. The maximum frequency offset is
160: * about +-500000 ns/s and the resolution is about 2.3e-10 ns/s.
161: *
162: * 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
163: * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
164: * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
165: * |s s s s s s s s s s s s s| ns/s |
166: * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
167: * | fraction |
168: * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
169: */
170: /*
171: * The following variables establish the state of the PLL/FLL and the
172: * residual time and frequency offset of the local clock.
173: */
174: #define SHIFT_PLL 4 /* PLL loop gain (shift) */
175: #define SHIFT_FLL 2 /* FLL loop gain (shift) */
176:
177: static int time_state = TIME_OK; /* clock state */
178: static int time_status = STA_UNSYNC; /* clock status bits */
179: static long time_tai; /* TAI offset (s) */
180: static long time_monitor; /* last time offset scaled (ns) */
181: static long time_constant; /* poll interval (shift) (s) */
182: static long time_precision = 1; /* clock precision (ns) */
183: static long time_maxerror = MAXPHASE / 1000; /* maximum error (us) */
184: static long time_esterror = MAXPHASE / 1000; /* estimated error (us) */
1.53 tsutsui 185: static time_t time_reftime; /* time at last adjustment (s) */
1.33 kardel 186: static l_fp time_offset; /* time offset (ns) */
187: static l_fp time_freq; /* frequency offset (ns/s) */
188: #endif /* NTP */
189:
190: static l_fp time_adj; /* tick adjust (ns/s) */
191: int64_t time_adjtime; /* correction from adjtime(2) (usec) */
192:
193: extern int time_adjusted; /* ntp might have changed the system time */
194:
195: #ifdef NTP
196: #ifdef PPS_SYNC
197: /*
198: * The following variables are used when a pulse-per-second (PPS) signal
199: * is available and connected via a modem control lead. They establish
200: * the engineering parameters of the clock discipline loop when
201: * controlled by the PPS signal.
202: */
203: #define PPS_FAVG 2 /* min freq avg interval (s) (shift) */
204: #define PPS_FAVGDEF 8 /* default freq avg int (s) (shift) */
205: #define PPS_FAVGMAX 15 /* max freq avg interval (s) (shift) */
206: #define PPS_PAVG 4 /* phase avg interval (s) (shift) */
207: #define PPS_VALID 120 /* PPS signal watchdog max (s) */
208: #define PPS_MAXWANDER 100000 /* max PPS wander (ns/s) */
209: #define PPS_POPCORN 2 /* popcorn spike threshold (shift) */
210:
211: static struct timespec pps_tf[3]; /* phase median filter */
212: static l_fp pps_freq; /* scaled frequency offset (ns/s) */
213: static long pps_fcount; /* frequency accumulator */
214: static long pps_jitter; /* nominal jitter (ns) */
215: static long pps_stabil; /* nominal stability (scaled ns/s) */
216: static long pps_lastsec; /* time at last calibration (s) */
217: static int pps_valid; /* signal watchdog counter */
218: static int pps_shift = PPS_FAVG; /* interval duration (s) (shift) */
219: static int pps_shiftmax = PPS_FAVGDEF; /* max interval duration (s) (shift) */
220: static int pps_intcnt; /* wander counter */
221:
222: /*
223: * PPS signal quality monitors
224: */
225: static long pps_calcnt; /* calibration intervals */
226: static long pps_jitcnt; /* jitter limit exceeded */
227: static long pps_stbcnt; /* stability limit exceeded */
228: static long pps_errcnt; /* calibration errors */
229: #endif /* PPS_SYNC */
230: /*
231: * End of phase/frequency-lock loop (PLL/FLL) definitions
232: */
233:
234: static void hardupdate(long offset);
235:
236: /*
237: * ntp_gettime() - NTP user application interface
238: */
239: void
1.45 dsl 240: ntp_gettime(struct ntptimeval *ntv)
1.33 kardel 241: {
1.57.18.1! christos 242: memset(ntv, 0, sizeof(*ntv));
1.48 ad 243:
244: mutex_spin_enter(&timecounter_lock);
1.33 kardel 245: nanotime(&ntv->time);
246: ntv->maxerror = time_maxerror;
247: ntv->esterror = time_esterror;
248: ntv->tai = time_tai;
249: ntv->time_state = time_state;
1.48 ad 250: mutex_spin_exit(&timecounter_lock);
1.33 kardel 251: }
252:
253: /* ARGSUSED */
254: /*
255: * ntp_adjtime() - NTP daemon application interface
256: */
257: int
1.45 dsl 258: sys_ntp_adjtime(struct lwp *l, const struct sys_ntp_adjtime_args *uap, register_t *retval)
1.33 kardel 259: {
1.45 dsl 260: /* {
1.33 kardel 261: syscallarg(struct timex *) tp;
1.45 dsl 262: } */
1.33 kardel 263: struct timex ntv;
1.56 maxv 264: int error;
1.33 kardel 265:
1.43 christos 266: error = copyin((void *)SCARG(uap, tp), (void *)&ntv, sizeof(ntv));
1.35 ad 267: if (error != 0)
1.33 kardel 268: return (error);
269:
1.37 elad 270: if (ntv.modes != 0 && (error = kauth_authorize_system(l->l_cred,
271: KAUTH_SYSTEM_TIME, KAUTH_REQ_SYSTEM_TIME_NTPADJTIME, NULL,
1.36 elad 272: NULL, NULL)) != 0)
1.33 kardel 273: return (error);
274:
275: ntp_adjtime1(&ntv);
276:
1.43 christos 277: error = copyout((void *)&ntv, (void *)SCARG(uap, tp), sizeof(ntv));
1.35 ad 278: if (!error)
1.33 kardel 279: *retval = ntp_timestatus();
1.35 ad 280:
1.33 kardel 281: return error;
282: }
283:
284: void
1.45 dsl 285: ntp_adjtime1(struct timex *ntv)
1.33 kardel 286: {
287: long freq;
288: int modes;
289:
290: /*
291: * Update selected clock variables - only the superuser can
292: * change anything. Note that there is no error checking here on
293: * the assumption the superuser should know what it is doing.
294: * Note that either the time constant or TAI offset are loaded
295: * from the ntv.constant member, depending on the mode bits. If
296: * the STA_PLL bit in the status word is cleared, the state and
297: * status words are reset to the initial values at boot.
298: */
1.48 ad 299: mutex_spin_enter(&timecounter_lock);
1.33 kardel 300: modes = ntv->modes;
301: if (modes != 0)
302: /* We need to save the system time during shutdown */
303: time_adjusted |= 2;
304: if (modes & MOD_MAXERROR)
305: time_maxerror = ntv->maxerror;
306: if (modes & MOD_ESTERROR)
307: time_esterror = ntv->esterror;
308: if (modes & MOD_STATUS) {
309: if (time_status & STA_PLL && !(ntv->status & STA_PLL)) {
310: time_state = TIME_OK;
311: time_status = STA_UNSYNC;
312: #ifdef PPS_SYNC
313: pps_shift = PPS_FAVG;
314: #endif /* PPS_SYNC */
315: }
316: time_status &= STA_RONLY;
317: time_status |= ntv->status & ~STA_RONLY;
318: }
319: if (modes & MOD_TIMECONST) {
320: if (ntv->constant < 0)
321: time_constant = 0;
322: else if (ntv->constant > MAXTC)
323: time_constant = MAXTC;
324: else
325: time_constant = ntv->constant;
326: }
327: if (modes & MOD_TAI) {
328: if (ntv->constant > 0) /* XXX zero & negative numbers ? */
329: time_tai = ntv->constant;
330: }
331: #ifdef PPS_SYNC
332: if (modes & MOD_PPSMAX) {
333: if (ntv->shift < PPS_FAVG)
334: pps_shiftmax = PPS_FAVG;
335: else if (ntv->shift > PPS_FAVGMAX)
336: pps_shiftmax = PPS_FAVGMAX;
337: else
338: pps_shiftmax = ntv->shift;
339: }
340: #endif /* PPS_SYNC */
341: if (modes & MOD_NANO)
342: time_status |= STA_NANO;
343: if (modes & MOD_MICRO)
344: time_status &= ~STA_NANO;
345: if (modes & MOD_CLKB)
346: time_status |= STA_CLK;
347: if (modes & MOD_CLKA)
348: time_status &= ~STA_CLK;
349: if (modes & MOD_FREQUENCY) {
350: freq = (ntv->freq * 1000LL) >> 16;
351: if (freq > MAXFREQ)
352: L_LINT(time_freq, MAXFREQ);
353: else if (freq < -MAXFREQ)
354: L_LINT(time_freq, -MAXFREQ);
355: else {
356: /*
357: * ntv.freq is [PPM * 2^16] = [us/s * 2^16]
358: * time_freq is [ns/s * 2^32]
359: */
360: time_freq = ntv->freq * 1000LL * 65536LL;
361: }
362: #ifdef PPS_SYNC
363: pps_freq = time_freq;
364: #endif /* PPS_SYNC */
365: }
366: if (modes & MOD_OFFSET) {
367: if (time_status & STA_NANO)
368: hardupdate(ntv->offset);
369: else
370: hardupdate(ntv->offset * 1000);
371: }
372:
373: /*
374: * Retrieve all clock variables. Note that the TAI offset is
375: * returned only by ntp_gettime();
376: */
377: if (time_status & STA_NANO)
378: ntv->offset = L_GINT(time_offset);
379: else
380: ntv->offset = L_GINT(time_offset) / 1000; /* XXX rounding ? */
381: ntv->freq = L_GINT((time_freq / 1000LL) << 16);
382: ntv->maxerror = time_maxerror;
383: ntv->esterror = time_esterror;
384: ntv->status = time_status;
385: ntv->constant = time_constant;
386: if (time_status & STA_NANO)
387: ntv->precision = time_precision;
388: else
389: ntv->precision = time_precision / 1000;
390: ntv->tolerance = MAXFREQ * SCALE_PPM;
391: #ifdef PPS_SYNC
392: ntv->shift = pps_shift;
393: ntv->ppsfreq = L_GINT((pps_freq / 1000LL) << 16);
394: if (time_status & STA_NANO)
395: ntv->jitter = pps_jitter;
396: else
397: ntv->jitter = pps_jitter / 1000;
398: ntv->stabil = pps_stabil;
399: ntv->calcnt = pps_calcnt;
400: ntv->errcnt = pps_errcnt;
401: ntv->jitcnt = pps_jitcnt;
402: ntv->stbcnt = pps_stbcnt;
403: #endif /* PPS_SYNC */
1.48 ad 404: mutex_spin_exit(&timecounter_lock);
1.33 kardel 405: }
406: #endif /* NTP */
407:
408: /*
409: * second_overflow() - called after ntp_tick_adjust()
410: *
411: * This routine is ordinarily called immediately following the above
412: * routine ntp_tick_adjust(). While these two routines are normally
413: * combined, they are separated here only for the purposes of
414: * simulation.
415: */
416: void
417: ntp_update_second(int64_t *adjustment, time_t *newsec)
418: {
419: int tickrate;
420: l_fp ftemp; /* 32/64-bit temporary */
421:
1.48 ad 422: KASSERT(mutex_owned(&timecounter_lock));
423:
1.33 kardel 424: #ifdef NTP
425:
426: /*
427: * On rollover of the second both the nanosecond and microsecond
428: * clocks are updated and the state machine cranked as
429: * necessary. The phase adjustment to be used for the next
430: * second is calculated and the maximum error is increased by
431: * the tolerance.
432: */
433: time_maxerror += MAXFREQ / 1000;
434:
435: /*
436: * Leap second processing. If in leap-insert state at
437: * the end of the day, the system clock is set back one
438: * second; if in leap-delete state, the system clock is
439: * set ahead one second. The nano_time() routine or
440: * external clock driver will insure that reported time
441: * is always monotonic.
442: */
443: switch (time_state) {
444:
445: /*
446: * No warning.
447: */
448: case TIME_OK:
449: if (time_status & STA_INS)
450: time_state = TIME_INS;
451: else if (time_status & STA_DEL)
452: time_state = TIME_DEL;
453: break;
454:
455: /*
456: * Insert second 23:59:60 following second
457: * 23:59:59.
458: */
459: case TIME_INS:
460: if (!(time_status & STA_INS))
461: time_state = TIME_OK;
462: else if ((*newsec) % 86400 == 0) {
463: (*newsec)--;
464: time_state = TIME_OOP;
465: time_tai++;
466: }
467: break;
468:
469: /*
470: * Delete second 23:59:59.
471: */
472: case TIME_DEL:
473: if (!(time_status & STA_DEL))
474: time_state = TIME_OK;
475: else if (((*newsec) + 1) % 86400 == 0) {
476: (*newsec)++;
477: time_tai--;
478: time_state = TIME_WAIT;
479: }
480: break;
481:
482: /*
483: * Insert second in progress.
484: */
485: case TIME_OOP:
486: time_state = TIME_WAIT;
487: break;
488:
489: /*
490: * Wait for status bits to clear.
491: */
492: case TIME_WAIT:
493: if (!(time_status & (STA_INS | STA_DEL)))
494: time_state = TIME_OK;
495: }
496:
497: /*
498: * Compute the total time adjustment for the next second
499: * in ns. The offset is reduced by a factor depending on
500: * whether the PPS signal is operating. Note that the
501: * value is in effect scaled by the clock frequency,
502: * since the adjustment is added at each tick interrupt.
503: */
504: ftemp = time_offset;
505: #ifdef PPS_SYNC
506: /* XXX even if PPS signal dies we should finish adjustment ? */
507: if (time_status & STA_PPSTIME && time_status &
508: STA_PPSSIGNAL)
509: L_RSHIFT(ftemp, pps_shift);
510: else
511: L_RSHIFT(ftemp, SHIFT_PLL + time_constant);
512: #else
513: L_RSHIFT(ftemp, SHIFT_PLL + time_constant);
514: #endif /* PPS_SYNC */
515: time_adj = ftemp;
516: L_SUB(time_offset, ftemp);
517: L_ADD(time_adj, time_freq);
518:
519: #ifdef PPS_SYNC
520: if (pps_valid > 0)
521: pps_valid--;
522: else
523: time_status &= ~STA_PPSSIGNAL;
524: #endif /* PPS_SYNC */
1.34 kardel 525: #else /* !NTP */
526: L_CLR(time_adj);
527: #endif /* !NTP */
1.33 kardel 528:
529: /*
530: * Apply any correction from adjtime(2). If more than one second
531: * off we slew at a rate of 5ms/s (5000 PPM) else 500us/s (500PPM)
532: * until the last second is slewed the final < 500 usecs.
533: */
534: if (time_adjtime != 0) {
535: if (time_adjtime > 1000000)
536: tickrate = 5000;
537: else if (time_adjtime < -1000000)
538: tickrate = -5000;
539: else if (time_adjtime > 500)
540: tickrate = 500;
541: else if (time_adjtime < -500)
542: tickrate = -500;
543: else
544: tickrate = time_adjtime;
545: time_adjtime -= tickrate;
546: L_LINT(ftemp, tickrate * 1000);
547: L_ADD(time_adj, ftemp);
548: }
549: *adjustment = time_adj;
550: }
551:
552: /*
553: * ntp_init() - initialize variables and structures
554: *
555: * This routine must be called after the kernel variables hz and tick
556: * are set or changed and before the next tick interrupt. In this
557: * particular implementation, these values are assumed set elsewhere in
558: * the kernel. The design allows the clock frequency and tick interval
559: * to be changed while the system is running. So, this routine should
560: * probably be integrated with the code that does that.
561: */
562: void
563: ntp_init(void)
564: {
565:
566: /*
567: * The following variables are initialized only at startup. Only
568: * those structures not cleared by the compiler need to be
569: * initialized, and these only in the simulator. In the actual
570: * kernel, any nonzero values here will quickly evaporate.
571: */
572: L_CLR(time_adj);
573: #ifdef NTP
574: L_CLR(time_offset);
575: L_CLR(time_freq);
576: #ifdef PPS_SYNC
577: pps_tf[0].tv_sec = pps_tf[0].tv_nsec = 0;
578: pps_tf[1].tv_sec = pps_tf[1].tv_nsec = 0;
579: pps_tf[2].tv_sec = pps_tf[2].tv_nsec = 0;
580: pps_fcount = 0;
581: L_CLR(pps_freq);
582: #endif /* PPS_SYNC */
583: #endif
584: }
585:
586: #ifdef NTP
587: /*
588: * hardupdate() - local clock update
589: *
590: * This routine is called by ntp_adjtime() to update the local clock
591: * phase and frequency. The implementation is of an adaptive-parameter,
592: * hybrid phase/frequency-lock loop (PLL/FLL). The routine computes new
593: * time and frequency offset estimates for each call. If the kernel PPS
594: * discipline code is configured (PPS_SYNC), the PPS signal itself
595: * determines the new time offset, instead of the calling argument.
596: * Presumably, calls to ntp_adjtime() occur only when the caller
597: * believes the local clock is valid within some bound (+-128 ms with
598: * NTP). If the caller's time is far different than the PPS time, an
599: * argument will ensue, and it's not clear who will lose.
600: *
601: * For uncompensated quartz crystal oscillators and nominal update
602: * intervals less than 256 s, operation should be in phase-lock mode,
603: * where the loop is disciplined to phase. For update intervals greater
604: * than 1024 s, operation should be in frequency-lock mode, where the
605: * loop is disciplined to frequency. Between 256 s and 1024 s, the mode
606: * is selected by the STA_MODE status bit.
607: *
608: * Note: splclock() is in effect.
609: */
610: void
611: hardupdate(long offset)
612: {
613: long mtemp;
614: l_fp ftemp;
615:
1.48 ad 616: KASSERT(mutex_owned(&timecounter_lock));
617:
1.33 kardel 618: /*
619: * Select how the phase is to be controlled and from which
620: * source. If the PPS signal is present and enabled to
621: * discipline the time, the PPS offset is used; otherwise, the
622: * argument offset is used.
623: */
624: if (!(time_status & STA_PLL))
625: return;
626: if (!(time_status & STA_PPSTIME && time_status &
627: STA_PPSSIGNAL)) {
628: if (offset > MAXPHASE)
629: time_monitor = MAXPHASE;
630: else if (offset < -MAXPHASE)
631: time_monitor = -MAXPHASE;
632: else
633: time_monitor = offset;
634: L_LINT(time_offset, time_monitor);
635: }
636:
637: /*
638: * Select how the frequency is to be controlled and in which
639: * mode (PLL or FLL). If the PPS signal is present and enabled
640: * to discipline the frequency, the PPS frequency is used;
641: * otherwise, the argument offset is used to compute it.
642: */
643: if (time_status & STA_PPSFREQ && time_status & STA_PPSSIGNAL) {
644: time_reftime = time_second;
645: return;
646: }
647: if (time_status & STA_FREQHOLD || time_reftime == 0)
648: time_reftime = time_second;
649: mtemp = time_second - time_reftime;
650: L_LINT(ftemp, time_monitor);
651: L_RSHIFT(ftemp, (SHIFT_PLL + 2 + time_constant) << 1);
652: L_MPY(ftemp, mtemp);
653: L_ADD(time_freq, ftemp);
654: time_status &= ~STA_MODE;
655: if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp >
656: MAXSEC)) {
657: L_LINT(ftemp, (time_monitor << 4) / mtemp);
658: L_RSHIFT(ftemp, SHIFT_FLL + 4);
659: L_ADD(time_freq, ftemp);
660: time_status |= STA_MODE;
661: }
662: time_reftime = time_second;
663: if (L_GINT(time_freq) > MAXFREQ)
664: L_LINT(time_freq, MAXFREQ);
665: else if (L_GINT(time_freq) < -MAXFREQ)
666: L_LINT(time_freq, -MAXFREQ);
667: }
668:
669: #ifdef PPS_SYNC
670: /*
671: * hardpps() - discipline CPU clock oscillator to external PPS signal
672: *
673: * This routine is called at each PPS interrupt in order to discipline
674: * the CPU clock oscillator to the PPS signal. It measures the PPS phase
675: * and leaves it in a handy spot for the hardclock() routine. It
676: * integrates successive PPS phase differences and calculates the
677: * frequency offset. This is used in hardclock() to discipline the CPU
678: * clock oscillator so that intrinsic frequency error is cancelled out.
679: * The code requires the caller to capture the time and hardware counter
680: * value at the on-time PPS signal transition.
681: *
682: * Note that, on some Unix systems, this routine runs at an interrupt
683: * priority level higher than the timer interrupt routine hardclock().
684: * Therefore, the variables used are distinct from the hardclock()
685: * variables, except for certain exceptions: The PPS frequency pps_freq
686: * and phase pps_offset variables are determined by this routine and
687: * updated atomically. The time_tolerance variable can be considered a
688: * constant, since it is infrequently changed, and then only when the
689: * PPS signal is disabled. The watchdog counter pps_valid is updated
690: * once per second by hardclock() and is atomically cleared in this
691: * routine.
692: */
693: void
694: hardpps(struct timespec *tsp, /* time at PPS */
695: long nsec /* hardware counter at PPS */)
696: {
697: long u_sec, u_nsec, v_nsec; /* temps */
698: l_fp ftemp;
699:
1.48 ad 700: KASSERT(mutex_owned(&timecounter_lock));
701:
1.33 kardel 702: /*
703: * The signal is first processed by a range gate and frequency
704: * discriminator. The range gate rejects noise spikes outside
705: * the range +-500 us. The frequency discriminator rejects input
706: * signals with apparent frequency outside the range 1 +-500
707: * PPM. If two hits occur in the same second, we ignore the
708: * later hit; if not and a hit occurs outside the range gate,
709: * keep the later hit for later comparison, but do not process
710: * it.
711: */
712: time_status |= STA_PPSSIGNAL | STA_PPSJITTER;
713: time_status &= ~(STA_PPSWANDER | STA_PPSERROR);
714: pps_valid = PPS_VALID;
715: u_sec = tsp->tv_sec;
716: u_nsec = tsp->tv_nsec;
717: if (u_nsec >= (NANOSECOND >> 1)) {
718: u_nsec -= NANOSECOND;
719: u_sec++;
720: }
721: v_nsec = u_nsec - pps_tf[0].tv_nsec;
722: if (u_sec == pps_tf[0].tv_sec && v_nsec < NANOSECOND -
723: MAXFREQ)
724: return;
725: pps_tf[2] = pps_tf[1];
726: pps_tf[1] = pps_tf[0];
727: pps_tf[0].tv_sec = u_sec;
728: pps_tf[0].tv_nsec = u_nsec;
729:
730: /*
731: * Compute the difference between the current and previous
732: * counter values. If the difference exceeds 0.5 s, assume it
733: * has wrapped around, so correct 1.0 s. If the result exceeds
734: * the tick interval, the sample point has crossed a tick
735: * boundary during the last second, so correct the tick. Very
736: * intricate.
737: */
738: u_nsec = nsec;
739: if (u_nsec > (NANOSECOND >> 1))
740: u_nsec -= NANOSECOND;
741: else if (u_nsec < -(NANOSECOND >> 1))
742: u_nsec += NANOSECOND;
743: pps_fcount += u_nsec;
744: if (v_nsec > MAXFREQ || v_nsec < -MAXFREQ)
745: return;
746: time_status &= ~STA_PPSJITTER;
747:
748: /*
749: * A three-stage median filter is used to help denoise the PPS
750: * time. The median sample becomes the time offset estimate; the
751: * difference between the other two samples becomes the time
752: * dispersion (jitter) estimate.
753: */
754: if (pps_tf[0].tv_nsec > pps_tf[1].tv_nsec) {
755: if (pps_tf[1].tv_nsec > pps_tf[2].tv_nsec) {
756: v_nsec = pps_tf[1].tv_nsec; /* 0 1 2 */
757: u_nsec = pps_tf[0].tv_nsec - pps_tf[2].tv_nsec;
758: } else if (pps_tf[2].tv_nsec > pps_tf[0].tv_nsec) {
759: v_nsec = pps_tf[0].tv_nsec; /* 2 0 1 */
760: u_nsec = pps_tf[2].tv_nsec - pps_tf[1].tv_nsec;
761: } else {
762: v_nsec = pps_tf[2].tv_nsec; /* 0 2 1 */
763: u_nsec = pps_tf[0].tv_nsec - pps_tf[1].tv_nsec;
764: }
765: } else {
766: if (pps_tf[1].tv_nsec < pps_tf[2].tv_nsec) {
767: v_nsec = pps_tf[1].tv_nsec; /* 2 1 0 */
768: u_nsec = pps_tf[2].tv_nsec - pps_tf[0].tv_nsec;
769: } else if (pps_tf[2].tv_nsec < pps_tf[0].tv_nsec) {
770: v_nsec = pps_tf[0].tv_nsec; /* 1 0 2 */
771: u_nsec = pps_tf[1].tv_nsec - pps_tf[2].tv_nsec;
772: } else {
773: v_nsec = pps_tf[2].tv_nsec; /* 1 2 0 */
774: u_nsec = pps_tf[1].tv_nsec - pps_tf[0].tv_nsec;
775: }
776: }
777:
778: /*
779: * Nominal jitter is due to PPS signal noise and interrupt
780: * latency. If it exceeds the popcorn threshold, the sample is
781: * discarded. otherwise, if so enabled, the time offset is
782: * updated. We can tolerate a modest loss of data here without
783: * much degrading time accuracy.
784: */
785: if (u_nsec > (pps_jitter << PPS_POPCORN)) {
786: time_status |= STA_PPSJITTER;
787: pps_jitcnt++;
788: } else if (time_status & STA_PPSTIME) {
789: time_monitor = -v_nsec;
790: L_LINT(time_offset, time_monitor);
791: }
792: pps_jitter += (u_nsec - pps_jitter) >> PPS_FAVG;
793: u_sec = pps_tf[0].tv_sec - pps_lastsec;
794: if (u_sec < (1 << pps_shift))
795: return;
796:
797: /*
798: * At the end of the calibration interval the difference between
799: * the first and last counter values becomes the scaled
800: * frequency. It will later be divided by the length of the
801: * interval to determine the frequency update. If the frequency
802: * exceeds a sanity threshold, or if the actual calibration
803: * interval is not equal to the expected length, the data are
804: * discarded. We can tolerate a modest loss of data here without
805: * much degrading frequency accuracy.
806: */
807: pps_calcnt++;
808: v_nsec = -pps_fcount;
809: pps_lastsec = pps_tf[0].tv_sec;
810: pps_fcount = 0;
811: u_nsec = MAXFREQ << pps_shift;
812: if (v_nsec > u_nsec || v_nsec < -u_nsec || u_sec != (1 <<
813: pps_shift)) {
814: time_status |= STA_PPSERROR;
815: pps_errcnt++;
816: return;
817: }
818:
819: /*
820: * Here the raw frequency offset and wander (stability) is
821: * calculated. If the wander is less than the wander threshold
822: * for four consecutive averaging intervals, the interval is
823: * doubled; if it is greater than the threshold for four
824: * consecutive intervals, the interval is halved. The scaled
825: * frequency offset is converted to frequency offset. The
826: * stability metric is calculated as the average of recent
827: * frequency changes, but is used only for performance
828: * monitoring.
829: */
830: L_LINT(ftemp, v_nsec);
831: L_RSHIFT(ftemp, pps_shift);
832: L_SUB(ftemp, pps_freq);
833: u_nsec = L_GINT(ftemp);
834: if (u_nsec > PPS_MAXWANDER) {
835: L_LINT(ftemp, PPS_MAXWANDER);
836: pps_intcnt--;
837: time_status |= STA_PPSWANDER;
838: pps_stbcnt++;
839: } else if (u_nsec < -PPS_MAXWANDER) {
840: L_LINT(ftemp, -PPS_MAXWANDER);
841: pps_intcnt--;
842: time_status |= STA_PPSWANDER;
843: pps_stbcnt++;
844: } else {
845: pps_intcnt++;
846: }
847: if (pps_intcnt >= 4) {
848: pps_intcnt = 4;
849: if (pps_shift < pps_shiftmax) {
850: pps_shift++;
851: pps_intcnt = 0;
852: }
853: } else if (pps_intcnt <= -4 || pps_shift > pps_shiftmax) {
854: pps_intcnt = -4;
855: if (pps_shift > PPS_FAVG) {
856: pps_shift--;
857: pps_intcnt = 0;
858: }
859: }
860: if (u_nsec < 0)
861: u_nsec = -u_nsec;
862: pps_stabil += (u_nsec * SCALE_PPM - pps_stabil) >> PPS_FAVG;
863:
864: /*
865: * The PPS frequency is recalculated and clamped to the maximum
866: * MAXFREQ. If enabled, the system clock frequency is updated as
867: * well.
868: */
869: L_ADD(pps_freq, ftemp);
870: u_nsec = L_GINT(pps_freq);
871: if (u_nsec > MAXFREQ)
872: L_LINT(pps_freq, MAXFREQ);
873: else if (u_nsec < -MAXFREQ)
874: L_LINT(pps_freq, -MAXFREQ);
875: if (time_status & STA_PPSFREQ)
876: time_freq = pps_freq;
877: }
878: #endif /* PPS_SYNC */
879: #endif /* NTP */
880:
881: #ifdef NTP
882: int
1.47 matt 883: ntp_timestatus(void)
1.33 kardel 884: {
1.48 ad 885: int rv;
886:
1.33 kardel 887: /*
888: * Status word error decode. If any of these conditions
889: * occur, an error is returned, instead of the status
890: * word. Most applications will care only about the fact
891: * the system clock may not be trusted, not about the
892: * details.
893: *
894: * Hardware or software error
895: */
1.48 ad 896: mutex_spin_enter(&timecounter_lock);
1.33 kardel 897: if ((time_status & (STA_UNSYNC | STA_CLOCKERR)) ||
898:
899: /*
900: * PPS signal lost when either time or frequency
901: * synchronization requested
902: */
903: (time_status & (STA_PPSFREQ | STA_PPSTIME) &&
904: !(time_status & STA_PPSSIGNAL)) ||
905:
906: /*
907: * PPS jitter exceeded when time synchronization
908: * requested
909: */
910: (time_status & STA_PPSTIME &&
911: time_status & STA_PPSJITTER) ||
912:
913: /*
914: * PPS wander exceeded or calibration error when
915: * frequency synchronization requested
916: */
917: (time_status & STA_PPSFREQ &&
918: time_status & (STA_PPSWANDER | STA_PPSERROR)))
1.48 ad 919: rv = TIME_ERROR;
1.33 kardel 920: else
1.48 ad 921: rv = time_state;
922: mutex_spin_exit(&timecounter_lock);
923:
924: return rv;
1.33 kardel 925: }
1.1 jonathan 926:
1.33 kardel 927: /*ARGSUSED*/
928: /*
929: * ntp_gettime() - NTP user application interface
930: */
931: int
1.51 christos 932: sys___ntp_gettime50(struct lwp *l, const struct sys___ntp_gettime50_args *uap, register_t *retval)
1.33 kardel 933: {
1.45 dsl 934: /* {
1.33 kardel 935: syscallarg(struct ntptimeval *) ntvp;
1.45 dsl 936: } */
1.33 kardel 937: struct ntptimeval ntv;
938: int error = 0;
939:
940: if (SCARG(uap, ntvp)) {
941: ntp_gettime(&ntv);
942:
1.43 christos 943: error = copyout((void *)&ntv, (void *)SCARG(uap, ntvp),
1.33 kardel 944: sizeof(ntv));
945: }
1.1 jonathan 946: if (!error) {
1.33 kardel 947: *retval = ntp_timestatus();
948: }
949: return(error);
950: }
1.1 jonathan 951:
952: /*
953: * return information about kernel precision timekeeping
954: */
1.25 atatat 955: static int
956: sysctl_kern_ntptime(SYSCTLFN_ARGS)
1.1 jonathan 957: {
1.25 atatat 958: struct sysctlnode node;
1.1 jonathan 959: struct ntptimeval ntv;
960:
1.31 drochner 961: ntp_gettime(&ntv);
1.25 atatat 962:
963: node = *rnode;
964: node.sysctl_data = &ntv;
965: node.sysctl_size = sizeof(ntv);
966: return (sysctl_lookup(SYSCTLFN_CALL(&node)));
967: }
968:
969: SYSCTL_SETUP(sysctl_kern_ntptime_setup, "sysctl kern.ntptime node setup")
970: {
971:
1.26 atatat 972: sysctl_createv(clog, 0, NULL, NULL,
973: CTLFLAG_PERMANENT,
1.27 atatat 974: CTLTYPE_STRUCT, "ntptime",
975: SYSCTL_DESCR("Kernel clock values for NTP"),
1.25 atatat 976: sysctl_kern_ntptime, 0, NULL,
977: sizeof(struct ntptimeval),
978: CTL_KERN, KERN_NTPTIME, CTL_EOL);
1.1 jonathan 979: }
1.13 bjh21 980: #endif /* !NTP */
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