1 /* $NetBSD: kern_ntptime.c,v 1.41 2006/11/01 10:17:58 yamt Exp $ */
2 #include <sys/types.h> /* XXX to get __HAVE_TIMECOUNTER, remove
3 after all ports are converted. */
4 #ifdef __HAVE_TIMECOUNTER
5
6 /*-
7 ***********************************************************************
8 * *
9 * Copyright (c) David L. Mills 1993-2001 *
10 * *
11 * Permission to use, copy, modify, and distribute this software and *
12 * its documentation for any purpose and without fee is hereby *
13 * granted, provided that the above copyright notice appears in all *
14 * copies and that both the copyright notice and this permission *
15 * notice appear in supporting documentation, and that the name *
16 * University of Delaware not be used in advertising or publicity *
17 * pertaining to distribution of the software without specific, *
18 * written prior permission. The University of Delaware makes no *
19 * representations about the suitability this software for any *
20 * purpose. It is provided "as is" without express or implied *
21 * warranty. *
22 * *
23 **********************************************************************/
24
25 /*
26 * Adapted from the original sources for FreeBSD and timecounters by:
27 * Poul-Henning Kamp <phk@FreeBSD.org>.
28 *
29 * The 32bit version of the "LP" macros seems a bit past its "sell by"
30 * date so I have retained only the 64bit version and included it directly
31 * in this file.
32 *
33 * Only minor changes done to interface with the timecounters over in
34 * sys/kern/kern_clock.c. Some of the comments below may be (even more)
35 * confusing and/or plain wrong in that context.
36 */
37
38 #include <sys/cdefs.h>
39 /* __FBSDID("$FreeBSD: src/sys/kern/kern_ntptime.c,v 1.59 2005/05/28 14:34:41 rwatson Exp $"); */
40 __KERNEL_RCSID(0, "$NetBSD: kern_ntptime.c,v 1.41 2006/11/01 10:17:58 yamt Exp $");
41
42 #include "opt_ntp.h"
43 #include "opt_compat_netbsd.h"
44
45 #include <sys/param.h>
46 #include <sys/resourcevar.h>
47 #include <sys/systm.h>
48 #include <sys/kernel.h>
49 #include <sys/proc.h>
50 #include <sys/sysctl.h>
51 #include <sys/timex.h>
52 #ifdef COMPAT_30
53 #include <compat/sys/timex.h>
54 #endif
55 #include <sys/vnode.h>
56 #include <sys/kauth.h>
57
58 #include <sys/mount.h>
59 #include <sys/sa.h>
60 #include <sys/syscallargs.h>
61
62 #include <machine/cpu.h>
63
64 /*
65 * Single-precision macros for 64-bit machines
66 */
67 typedef int64_t l_fp;
68 #define L_ADD(v, u) ((v) += (u))
69 #define L_SUB(v, u) ((v) -= (u))
70 #define L_ADDHI(v, a) ((v) += (int64_t)(a) << 32)
71 #define L_NEG(v) ((v) = -(v))
72 #define L_RSHIFT(v, n) \
73 do { \
74 if ((v) < 0) \
75 (v) = -(-(v) >> (n)); \
76 else \
77 (v) = (v) >> (n); \
78 } while (0)
79 #define L_MPY(v, a) ((v) *= (a))
80 #define L_CLR(v) ((v) = 0)
81 #define L_ISNEG(v) ((v) < 0)
82 #define L_LINT(v, a) ((v) = (int64_t)(a) << 32)
83 #define L_GINT(v) ((v) < 0 ? -(-(v) >> 32) : (v) >> 32)
84
85 #ifdef NTP
86 /*
87 * Generic NTP kernel interface
88 *
89 * These routines constitute the Network Time Protocol (NTP) interfaces
90 * for user and daemon application programs. The ntp_gettime() routine
91 * provides the time, maximum error (synch distance) and estimated error
92 * (dispersion) to client user application programs. The ntp_adjtime()
93 * routine is used by the NTP daemon to adjust the system clock to an
94 * externally derived time. The time offset and related variables set by
95 * this routine are used by other routines in this module to adjust the
96 * phase and frequency of the clock discipline loop which controls the
97 * system clock.
98 *
99 * When the kernel time is reckoned directly in nanoseconds (NTP_NANO
100 * defined), the time at each tick interrupt is derived directly from
101 * the kernel time variable. When the kernel time is reckoned in
102 * microseconds, (NTP_NANO undefined), the time is derived from the
103 * kernel time variable together with a variable representing the
104 * leftover nanoseconds at the last tick interrupt. In either case, the
105 * current nanosecond time is reckoned from these values plus an
106 * interpolated value derived by the clock routines in another
107 * architecture-specific module. The interpolation can use either a
108 * dedicated counter or a processor cycle counter (PCC) implemented in
109 * some architectures.
110 *
111 * Note that all routines must run at priority splclock or higher.
112 */
113 /*
114 * Phase/frequency-lock loop (PLL/FLL) definitions
115 *
116 * The nanosecond clock discipline uses two variable types, time
117 * variables and frequency variables. Both types are represented as 64-
118 * bit fixed-point quantities with the decimal point between two 32-bit
119 * halves. On a 32-bit machine, each half is represented as a single
120 * word and mathematical operations are done using multiple-precision
121 * arithmetic. On a 64-bit machine, ordinary computer arithmetic is
122 * used.
123 *
124 * A time variable is a signed 64-bit fixed-point number in ns and
125 * fraction. It represents the remaining time offset to be amortized
126 * over succeeding tick interrupts. The maximum time offset is about
127 * 0.5 s and the resolution is about 2.3e-10 ns.
128 *
129 * 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
130 * 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
131 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
132 * |s s s| ns |
133 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
134 * | fraction |
135 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
136 *
137 * A frequency variable is a signed 64-bit fixed-point number in ns/s
138 * and fraction. It represents the ns and fraction to be added to the
139 * kernel time variable at each second. The maximum frequency offset is
140 * about +-500000 ns/s and the resolution is about 2.3e-10 ns/s.
141 *
142 * 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
143 * 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
144 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
145 * |s s s s s s s s s s s s s| ns/s |
146 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
147 * | fraction |
148 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
149 */
150 /*
151 * The following variables establish the state of the PLL/FLL and the
152 * residual time and frequency offset of the local clock.
153 */
154 #define SHIFT_PLL 4 /* PLL loop gain (shift) */
155 #define SHIFT_FLL 2 /* FLL loop gain (shift) */
156
157 static int time_state = TIME_OK; /* clock state */
158 static int time_status = STA_UNSYNC; /* clock status bits */
159 static long time_tai; /* TAI offset (s) */
160 static long time_monitor; /* last time offset scaled (ns) */
161 static long time_constant; /* poll interval (shift) (s) */
162 static long time_precision = 1; /* clock precision (ns) */
163 static long time_maxerror = MAXPHASE / 1000; /* maximum error (us) */
164 static long time_esterror = MAXPHASE / 1000; /* estimated error (us) */
165 static long time_reftime; /* time at last adjustment (s) */
166 static l_fp time_offset; /* time offset (ns) */
167 static l_fp time_freq; /* frequency offset (ns/s) */
168 #endif /* NTP */
169
170 static l_fp time_adj; /* tick adjust (ns/s) */
171 int64_t time_adjtime; /* correction from adjtime(2) (usec) */
172
173 extern int time_adjusted; /* ntp might have changed the system time */
174
175 #ifdef NTP
176 #ifdef PPS_SYNC
177 /*
178 * The following variables are used when a pulse-per-second (PPS) signal
179 * is available and connected via a modem control lead. They establish
180 * the engineering parameters of the clock discipline loop when
181 * controlled by the PPS signal.
182 */
183 #define PPS_FAVG 2 /* min freq avg interval (s) (shift) */
184 #define PPS_FAVGDEF 8 /* default freq avg int (s) (shift) */
185 #define PPS_FAVGMAX 15 /* max freq avg interval (s) (shift) */
186 #define PPS_PAVG 4 /* phase avg interval (s) (shift) */
187 #define PPS_VALID 120 /* PPS signal watchdog max (s) */
188 #define PPS_MAXWANDER 100000 /* max PPS wander (ns/s) */
189 #define PPS_POPCORN 2 /* popcorn spike threshold (shift) */
190
191 static struct timespec pps_tf[3]; /* phase median filter */
192 static l_fp pps_freq; /* scaled frequency offset (ns/s) */
193 static long pps_fcount; /* frequency accumulator */
194 static long pps_jitter; /* nominal jitter (ns) */
195 static long pps_stabil; /* nominal stability (scaled ns/s) */
196 static long pps_lastsec; /* time at last calibration (s) */
197 static int pps_valid; /* signal watchdog counter */
198 static int pps_shift = PPS_FAVG; /* interval duration (s) (shift) */
199 static int pps_shiftmax = PPS_FAVGDEF; /* max interval duration (s) (shift) */
200 static int pps_intcnt; /* wander counter */
201
202 /*
203 * PPS signal quality monitors
204 */
205 static long pps_calcnt; /* calibration intervals */
206 static long pps_jitcnt; /* jitter limit exceeded */
207 static long pps_stbcnt; /* stability limit exceeded */
208 static long pps_errcnt; /* calibration errors */
209 #endif /* PPS_SYNC */
210 /*
211 * End of phase/frequency-lock loop (PLL/FLL) definitions
212 */
213
214 static void hardupdate(long offset);
215
216 /*
217 * ntp_gettime() - NTP user application interface
218 */
219 void
220 ntp_gettime(ntv)
221 struct ntptimeval *ntv;
222 {
223 nanotime(&ntv->time);
224 ntv->maxerror = time_maxerror;
225 ntv->esterror = time_esterror;
226 ntv->tai = time_tai;
227 ntv->time_state = time_state;
228 }
229
230 /* ARGSUSED */
231 /*
232 * ntp_adjtime() - NTP daemon application interface
233 */
234 int
235 sys_ntp_adjtime(l, v, retval)
236 struct lwp *l;
237 void *v;
238 register_t *retval;
239 {
240 struct sys_ntp_adjtime_args /* {
241 syscallarg(struct timex *) tp;
242 } */ *uap = v;
243 struct timex ntv;
244 int error = 0;
245
246 error = copyin((caddr_t)SCARG(uap, tp), (caddr_t)&ntv, sizeof(ntv));
247 if (error != 0)
248 return (error);
249
250 if (ntv.modes != 0 && (error = kauth_authorize_system(l->l_cred,
251 KAUTH_SYSTEM_TIME, KAUTH_REQ_SYSTEM_TIME_NTPADJTIME, NULL,
252 NULL, NULL)) != 0)
253 return (error);
254
255 ntp_adjtime1(&ntv);
256
257 error = copyout((caddr_t)&ntv, (caddr_t)SCARG(uap, tp), sizeof(ntv));
258 if (!error)
259 *retval = ntp_timestatus();
260
261 return error;
262 }
263
264 void
265 ntp_adjtime1(ntv)
266 struct timex *ntv;
267 {
268 long freq;
269 int modes;
270 int s;
271
272 /*
273 * Update selected clock variables - only the superuser can
274 * change anything. Note that there is no error checking here on
275 * the assumption the superuser should know what it is doing.
276 * Note that either the time constant or TAI offset are loaded
277 * from the ntv.constant member, depending on the mode bits. If
278 * the STA_PLL bit in the status word is cleared, the state and
279 * status words are reset to the initial values at boot.
280 */
281 modes = ntv->modes;
282 if (modes != 0)
283 /* We need to save the system time during shutdown */
284 time_adjusted |= 2;
285 s = splclock();
286 if (modes & MOD_MAXERROR)
287 time_maxerror = ntv->maxerror;
288 if (modes & MOD_ESTERROR)
289 time_esterror = ntv->esterror;
290 if (modes & MOD_STATUS) {
291 if (time_status & STA_PLL && !(ntv->status & STA_PLL)) {
292 time_state = TIME_OK;
293 time_status = STA_UNSYNC;
294 #ifdef PPS_SYNC
295 pps_shift = PPS_FAVG;
296 #endif /* PPS_SYNC */
297 }
298 time_status &= STA_RONLY;
299 time_status |= ntv->status & ~STA_RONLY;
300 }
301 if (modes & MOD_TIMECONST) {
302 if (ntv->constant < 0)
303 time_constant = 0;
304 else if (ntv->constant > MAXTC)
305 time_constant = MAXTC;
306 else
307 time_constant = ntv->constant;
308 }
309 if (modes & MOD_TAI) {
310 if (ntv->constant > 0) /* XXX zero & negative numbers ? */
311 time_tai = ntv->constant;
312 }
313 #ifdef PPS_SYNC
314 if (modes & MOD_PPSMAX) {
315 if (ntv->shift < PPS_FAVG)
316 pps_shiftmax = PPS_FAVG;
317 else if (ntv->shift > PPS_FAVGMAX)
318 pps_shiftmax = PPS_FAVGMAX;
319 else
320 pps_shiftmax = ntv->shift;
321 }
322 #endif /* PPS_SYNC */
323 if (modes & MOD_NANO)
324 time_status |= STA_NANO;
325 if (modes & MOD_MICRO)
326 time_status &= ~STA_NANO;
327 if (modes & MOD_CLKB)
328 time_status |= STA_CLK;
329 if (modes & MOD_CLKA)
330 time_status &= ~STA_CLK;
331 if (modes & MOD_FREQUENCY) {
332 freq = (ntv->freq * 1000LL) >> 16;
333 if (freq > MAXFREQ)
334 L_LINT(time_freq, MAXFREQ);
335 else if (freq < -MAXFREQ)
336 L_LINT(time_freq, -MAXFREQ);
337 else {
338 /*
339 * ntv.freq is [PPM * 2^16] = [us/s * 2^16]
340 * time_freq is [ns/s * 2^32]
341 */
342 time_freq = ntv->freq * 1000LL * 65536LL;
343 }
344 #ifdef PPS_SYNC
345 pps_freq = time_freq;
346 #endif /* PPS_SYNC */
347 }
348 if (modes & MOD_OFFSET) {
349 if (time_status & STA_NANO)
350 hardupdate(ntv->offset);
351 else
352 hardupdate(ntv->offset * 1000);
353 }
354
355 /*
356 * Retrieve all clock variables. Note that the TAI offset is
357 * returned only by ntp_gettime();
358 */
359 if (time_status & STA_NANO)
360 ntv->offset = L_GINT(time_offset);
361 else
362 ntv->offset = L_GINT(time_offset) / 1000; /* XXX rounding ? */
363 ntv->freq = L_GINT((time_freq / 1000LL) << 16);
364 ntv->maxerror = time_maxerror;
365 ntv->esterror = time_esterror;
366 ntv->status = time_status;
367 ntv->constant = time_constant;
368 if (time_status & STA_NANO)
369 ntv->precision = time_precision;
370 else
371 ntv->precision = time_precision / 1000;
372 ntv->tolerance = MAXFREQ * SCALE_PPM;
373 #ifdef PPS_SYNC
374 ntv->shift = pps_shift;
375 ntv->ppsfreq = L_GINT((pps_freq / 1000LL) << 16);
376 if (time_status & STA_NANO)
377 ntv->jitter = pps_jitter;
378 else
379 ntv->jitter = pps_jitter / 1000;
380 ntv->stabil = pps_stabil;
381 ntv->calcnt = pps_calcnt;
382 ntv->errcnt = pps_errcnt;
383 ntv->jitcnt = pps_jitcnt;
384 ntv->stbcnt = pps_stbcnt;
385 #endif /* PPS_SYNC */
386 splx(s);
387 }
388 #endif /* NTP */
389
390 /*
391 * second_overflow() - called after ntp_tick_adjust()
392 *
393 * This routine is ordinarily called immediately following the above
394 * routine ntp_tick_adjust(). While these two routines are normally
395 * combined, they are separated here only for the purposes of
396 * simulation.
397 */
398 void
399 ntp_update_second(int64_t *adjustment, time_t *newsec)
400 {
401 int tickrate;
402 l_fp ftemp; /* 32/64-bit temporary */
403
404 #ifdef NTP
405
406 /*
407 * On rollover of the second both the nanosecond and microsecond
408 * clocks are updated and the state machine cranked as
409 * necessary. The phase adjustment to be used for the next
410 * second is calculated and the maximum error is increased by
411 * the tolerance.
412 */
413 time_maxerror += MAXFREQ / 1000;
414
415 /*
416 * Leap second processing. If in leap-insert state at
417 * the end of the day, the system clock is set back one
418 * second; if in leap-delete state, the system clock is
419 * set ahead one second. The nano_time() routine or
420 * external clock driver will insure that reported time
421 * is always monotonic.
422 */
423 switch (time_state) {
424
425 /*
426 * No warning.
427 */
428 case TIME_OK:
429 if (time_status & STA_INS)
430 time_state = TIME_INS;
431 else if (time_status & STA_DEL)
432 time_state = TIME_DEL;
433 break;
434
435 /*
436 * Insert second 23:59:60 following second
437 * 23:59:59.
438 */
439 case TIME_INS:
440 if (!(time_status & STA_INS))
441 time_state = TIME_OK;
442 else if ((*newsec) % 86400 == 0) {
443 (*newsec)--;
444 time_state = TIME_OOP;
445 time_tai++;
446 }
447 break;
448
449 /*
450 * Delete second 23:59:59.
451 */
452 case TIME_DEL:
453 if (!(time_status & STA_DEL))
454 time_state = TIME_OK;
455 else if (((*newsec) + 1) % 86400 == 0) {
456 (*newsec)++;
457 time_tai--;
458 time_state = TIME_WAIT;
459 }
460 break;
461
462 /*
463 * Insert second in progress.
464 */
465 case TIME_OOP:
466 time_state = TIME_WAIT;
467 break;
468
469 /*
470 * Wait for status bits to clear.
471 */
472 case TIME_WAIT:
473 if (!(time_status & (STA_INS | STA_DEL)))
474 time_state = TIME_OK;
475 }
476
477 /*
478 * Compute the total time adjustment for the next second
479 * in ns. The offset is reduced by a factor depending on
480 * whether the PPS signal is operating. Note that the
481 * value is in effect scaled by the clock frequency,
482 * since the adjustment is added at each tick interrupt.
483 */
484 ftemp = time_offset;
485 #ifdef PPS_SYNC
486 /* XXX even if PPS signal dies we should finish adjustment ? */
487 if (time_status & STA_PPSTIME && time_status &
488 STA_PPSSIGNAL)
489 L_RSHIFT(ftemp, pps_shift);
490 else
491 L_RSHIFT(ftemp, SHIFT_PLL + time_constant);
492 #else
493 L_RSHIFT(ftemp, SHIFT_PLL + time_constant);
494 #endif /* PPS_SYNC */
495 time_adj = ftemp;
496 L_SUB(time_offset, ftemp);
497 L_ADD(time_adj, time_freq);
498
499 #ifdef PPS_SYNC
500 if (pps_valid > 0)
501 pps_valid--;
502 else
503 time_status &= ~STA_PPSSIGNAL;
504 #endif /* PPS_SYNC */
505 #else /* !NTP */
506 L_CLR(time_adj);
507 #endif /* !NTP */
508
509 /*
510 * Apply any correction from adjtime(2). If more than one second
511 * off we slew at a rate of 5ms/s (5000 PPM) else 500us/s (500PPM)
512 * until the last second is slewed the final < 500 usecs.
513 */
514 if (time_adjtime != 0) {
515 if (time_adjtime > 1000000)
516 tickrate = 5000;
517 else if (time_adjtime < -1000000)
518 tickrate = -5000;
519 else if (time_adjtime > 500)
520 tickrate = 500;
521 else if (time_adjtime < -500)
522 tickrate = -500;
523 else
524 tickrate = time_adjtime;
525 time_adjtime -= tickrate;
526 L_LINT(ftemp, tickrate * 1000);
527 L_ADD(time_adj, ftemp);
528 }
529 *adjustment = time_adj;
530 }
531
532 /*
533 * ntp_init() - initialize variables and structures
534 *
535 * This routine must be called after the kernel variables hz and tick
536 * are set or changed and before the next tick interrupt. In this
537 * particular implementation, these values are assumed set elsewhere in
538 * the kernel. The design allows the clock frequency and tick interval
539 * to be changed while the system is running. So, this routine should
540 * probably be integrated with the code that does that.
541 */
542 void
543 ntp_init(void)
544 {
545
546 /*
547 * The following variables are initialized only at startup. Only
548 * those structures not cleared by the compiler need to be
549 * initialized, and these only in the simulator. In the actual
550 * kernel, any nonzero values here will quickly evaporate.
551 */
552 L_CLR(time_adj);
553 #ifdef NTP
554 L_CLR(time_offset);
555 L_CLR(time_freq);
556 #ifdef PPS_SYNC
557 pps_tf[0].tv_sec = pps_tf[0].tv_nsec = 0;
558 pps_tf[1].tv_sec = pps_tf[1].tv_nsec = 0;
559 pps_tf[2].tv_sec = pps_tf[2].tv_nsec = 0;
560 pps_fcount = 0;
561 L_CLR(pps_freq);
562 #endif /* PPS_SYNC */
563 #endif
564 }
565
566 #ifdef NTP
567 /*
568 * hardupdate() - local clock update
569 *
570 * This routine is called by ntp_adjtime() to update the local clock
571 * phase and frequency. The implementation is of an adaptive-parameter,
572 * hybrid phase/frequency-lock loop (PLL/FLL). The routine computes new
573 * time and frequency offset estimates for each call. If the kernel PPS
574 * discipline code is configured (PPS_SYNC), the PPS signal itself
575 * determines the new time offset, instead of the calling argument.
576 * Presumably, calls to ntp_adjtime() occur only when the caller
577 * believes the local clock is valid within some bound (+-128 ms with
578 * NTP). If the caller's time is far different than the PPS time, an
579 * argument will ensue, and it's not clear who will lose.
580 *
581 * For uncompensated quartz crystal oscillators and nominal update
582 * intervals less than 256 s, operation should be in phase-lock mode,
583 * where the loop is disciplined to phase. For update intervals greater
584 * than 1024 s, operation should be in frequency-lock mode, where the
585 * loop is disciplined to frequency. Between 256 s and 1024 s, the mode
586 * is selected by the STA_MODE status bit.
587 *
588 * Note: splclock() is in effect.
589 */
590 void
591 hardupdate(long offset)
592 {
593 long mtemp;
594 l_fp ftemp;
595
596 /*
597 * Select how the phase is to be controlled and from which
598 * source. If the PPS signal is present and enabled to
599 * discipline the time, the PPS offset is used; otherwise, the
600 * argument offset is used.
601 */
602 if (!(time_status & STA_PLL))
603 return;
604 if (!(time_status & STA_PPSTIME && time_status &
605 STA_PPSSIGNAL)) {
606 if (offset > MAXPHASE)
607 time_monitor = MAXPHASE;
608 else if (offset < -MAXPHASE)
609 time_monitor = -MAXPHASE;
610 else
611 time_monitor = offset;
612 L_LINT(time_offset, time_monitor);
613 }
614
615 /*
616 * Select how the frequency is to be controlled and in which
617 * mode (PLL or FLL). If the PPS signal is present and enabled
618 * to discipline the frequency, the PPS frequency is used;
619 * otherwise, the argument offset is used to compute it.
620 */
621 if (time_status & STA_PPSFREQ && time_status & STA_PPSSIGNAL) {
622 time_reftime = time_second;
623 return;
624 }
625 if (time_status & STA_FREQHOLD || time_reftime == 0)
626 time_reftime = time_second;
627 mtemp = time_second - time_reftime;
628 L_LINT(ftemp, time_monitor);
629 L_RSHIFT(ftemp, (SHIFT_PLL + 2 + time_constant) << 1);
630 L_MPY(ftemp, mtemp);
631 L_ADD(time_freq, ftemp);
632 time_status &= ~STA_MODE;
633 if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp >
634 MAXSEC)) {
635 L_LINT(ftemp, (time_monitor << 4) / mtemp);
636 L_RSHIFT(ftemp, SHIFT_FLL + 4);
637 L_ADD(time_freq, ftemp);
638 time_status |= STA_MODE;
639 }
640 time_reftime = time_second;
641 if (L_GINT(time_freq) > MAXFREQ)
642 L_LINT(time_freq, MAXFREQ);
643 else if (L_GINT(time_freq) < -MAXFREQ)
644 L_LINT(time_freq, -MAXFREQ);
645 }
646
647 #ifdef PPS_SYNC
648 /*
649 * hardpps() - discipline CPU clock oscillator to external PPS signal
650 *
651 * This routine is called at each PPS interrupt in order to discipline
652 * the CPU clock oscillator to the PPS signal. It measures the PPS phase
653 * and leaves it in a handy spot for the hardclock() routine. It
654 * integrates successive PPS phase differences and calculates the
655 * frequency offset. This is used in hardclock() to discipline the CPU
656 * clock oscillator so that intrinsic frequency error is cancelled out.
657 * The code requires the caller to capture the time and hardware counter
658 * value at the on-time PPS signal transition.
659 *
660 * Note that, on some Unix systems, this routine runs at an interrupt
661 * priority level higher than the timer interrupt routine hardclock().
662 * Therefore, the variables used are distinct from the hardclock()
663 * variables, except for certain exceptions: The PPS frequency pps_freq
664 * and phase pps_offset variables are determined by this routine and
665 * updated atomically. The time_tolerance variable can be considered a
666 * constant, since it is infrequently changed, and then only when the
667 * PPS signal is disabled. The watchdog counter pps_valid is updated
668 * once per second by hardclock() and is atomically cleared in this
669 * routine.
670 */
671 void
672 hardpps(struct timespec *tsp, /* time at PPS */
673 long nsec /* hardware counter at PPS */)
674 {
675 long u_sec, u_nsec, v_nsec; /* temps */
676 l_fp ftemp;
677
678 /*
679 * The signal is first processed by a range gate and frequency
680 * discriminator. The range gate rejects noise spikes outside
681 * the range +-500 us. The frequency discriminator rejects input
682 * signals with apparent frequency outside the range 1 +-500
683 * PPM. If two hits occur in the same second, we ignore the
684 * later hit; if not and a hit occurs outside the range gate,
685 * keep the later hit for later comparison, but do not process
686 * it.
687 */
688 time_status |= STA_PPSSIGNAL | STA_PPSJITTER;
689 time_status &= ~(STA_PPSWANDER | STA_PPSERROR);
690 pps_valid = PPS_VALID;
691 u_sec = tsp->tv_sec;
692 u_nsec = tsp->tv_nsec;
693 if (u_nsec >= (NANOSECOND >> 1)) {
694 u_nsec -= NANOSECOND;
695 u_sec++;
696 }
697 v_nsec = u_nsec - pps_tf[0].tv_nsec;
698 if (u_sec == pps_tf[0].tv_sec && v_nsec < NANOSECOND -
699 MAXFREQ)
700 return;
701 pps_tf[2] = pps_tf[1];
702 pps_tf[1] = pps_tf[0];
703 pps_tf[0].tv_sec = u_sec;
704 pps_tf[0].tv_nsec = u_nsec;
705
706 /*
707 * Compute the difference between the current and previous
708 * counter values. If the difference exceeds 0.5 s, assume it
709 * has wrapped around, so correct 1.0 s. If the result exceeds
710 * the tick interval, the sample point has crossed a tick
711 * boundary during the last second, so correct the tick. Very
712 * intricate.
713 */
714 u_nsec = nsec;
715 if (u_nsec > (NANOSECOND >> 1))
716 u_nsec -= NANOSECOND;
717 else if (u_nsec < -(NANOSECOND >> 1))
718 u_nsec += NANOSECOND;
719 pps_fcount += u_nsec;
720 if (v_nsec > MAXFREQ || v_nsec < -MAXFREQ)
721 return;
722 time_status &= ~STA_PPSJITTER;
723
724 /*
725 * A three-stage median filter is used to help denoise the PPS
726 * time. The median sample becomes the time offset estimate; the
727 * difference between the other two samples becomes the time
728 * dispersion (jitter) estimate.
729 */
730 if (pps_tf[0].tv_nsec > pps_tf[1].tv_nsec) {
731 if (pps_tf[1].tv_nsec > pps_tf[2].tv_nsec) {
732 v_nsec = pps_tf[1].tv_nsec; /* 0 1 2 */
733 u_nsec = pps_tf[0].tv_nsec - pps_tf[2].tv_nsec;
734 } else if (pps_tf[2].tv_nsec > pps_tf[0].tv_nsec) {
735 v_nsec = pps_tf[0].tv_nsec; /* 2 0 1 */
736 u_nsec = pps_tf[2].tv_nsec - pps_tf[1].tv_nsec;
737 } else {
738 v_nsec = pps_tf[2].tv_nsec; /* 0 2 1 */
739 u_nsec = pps_tf[0].tv_nsec - pps_tf[1].tv_nsec;
740 }
741 } else {
742 if (pps_tf[1].tv_nsec < pps_tf[2].tv_nsec) {
743 v_nsec = pps_tf[1].tv_nsec; /* 2 1 0 */
744 u_nsec = pps_tf[2].tv_nsec - pps_tf[0].tv_nsec;
745 } else if (pps_tf[2].tv_nsec < pps_tf[0].tv_nsec) {
746 v_nsec = pps_tf[0].tv_nsec; /* 1 0 2 */
747 u_nsec = pps_tf[1].tv_nsec - pps_tf[2].tv_nsec;
748 } else {
749 v_nsec = pps_tf[2].tv_nsec; /* 1 2 0 */
750 u_nsec = pps_tf[1].tv_nsec - pps_tf[0].tv_nsec;
751 }
752 }
753
754 /*
755 * Nominal jitter is due to PPS signal noise and interrupt
756 * latency. If it exceeds the popcorn threshold, the sample is
757 * discarded. otherwise, if so enabled, the time offset is
758 * updated. We can tolerate a modest loss of data here without
759 * much degrading time accuracy.
760 */
761 if (u_nsec > (pps_jitter << PPS_POPCORN)) {
762 time_status |= STA_PPSJITTER;
763 pps_jitcnt++;
764 } else if (time_status & STA_PPSTIME) {
765 time_monitor = -v_nsec;
766 L_LINT(time_offset, time_monitor);
767 }
768 pps_jitter += (u_nsec - pps_jitter) >> PPS_FAVG;
769 u_sec = pps_tf[0].tv_sec - pps_lastsec;
770 if (u_sec < (1 << pps_shift))
771 return;
772
773 /*
774 * At the end of the calibration interval the difference between
775 * the first and last counter values becomes the scaled
776 * frequency. It will later be divided by the length of the
777 * interval to determine the frequency update. If the frequency
778 * exceeds a sanity threshold, or if the actual calibration
779 * interval is not equal to the expected length, the data are
780 * discarded. We can tolerate a modest loss of data here without
781 * much degrading frequency accuracy.
782 */
783 pps_calcnt++;
784 v_nsec = -pps_fcount;
785 pps_lastsec = pps_tf[0].tv_sec;
786 pps_fcount = 0;
787 u_nsec = MAXFREQ << pps_shift;
788 if (v_nsec > u_nsec || v_nsec < -u_nsec || u_sec != (1 <<
789 pps_shift)) {
790 time_status |= STA_PPSERROR;
791 pps_errcnt++;
792 return;
793 }
794
795 /*
796 * Here the raw frequency offset and wander (stability) is
797 * calculated. If the wander is less than the wander threshold
798 * for four consecutive averaging intervals, the interval is
799 * doubled; if it is greater than the threshold for four
800 * consecutive intervals, the interval is halved. The scaled
801 * frequency offset is converted to frequency offset. The
802 * stability metric is calculated as the average of recent
803 * frequency changes, but is used only for performance
804 * monitoring.
805 */
806 L_LINT(ftemp, v_nsec);
807 L_RSHIFT(ftemp, pps_shift);
808 L_SUB(ftemp, pps_freq);
809 u_nsec = L_GINT(ftemp);
810 if (u_nsec > PPS_MAXWANDER) {
811 L_LINT(ftemp, PPS_MAXWANDER);
812 pps_intcnt--;
813 time_status |= STA_PPSWANDER;
814 pps_stbcnt++;
815 } else if (u_nsec < -PPS_MAXWANDER) {
816 L_LINT(ftemp, -PPS_MAXWANDER);
817 pps_intcnt--;
818 time_status |= STA_PPSWANDER;
819 pps_stbcnt++;
820 } else {
821 pps_intcnt++;
822 }
823 if (pps_intcnt >= 4) {
824 pps_intcnt = 4;
825 if (pps_shift < pps_shiftmax) {
826 pps_shift++;
827 pps_intcnt = 0;
828 }
829 } else if (pps_intcnt <= -4 || pps_shift > pps_shiftmax) {
830 pps_intcnt = -4;
831 if (pps_shift > PPS_FAVG) {
832 pps_shift--;
833 pps_intcnt = 0;
834 }
835 }
836 if (u_nsec < 0)
837 u_nsec = -u_nsec;
838 pps_stabil += (u_nsec * SCALE_PPM - pps_stabil) >> PPS_FAVG;
839
840 /*
841 * The PPS frequency is recalculated and clamped to the maximum
842 * MAXFREQ. If enabled, the system clock frequency is updated as
843 * well.
844 */
845 L_ADD(pps_freq, ftemp);
846 u_nsec = L_GINT(pps_freq);
847 if (u_nsec > MAXFREQ)
848 L_LINT(pps_freq, MAXFREQ);
849 else if (u_nsec < -MAXFREQ)
850 L_LINT(pps_freq, -MAXFREQ);
851 if (time_status & STA_PPSFREQ)
852 time_freq = pps_freq;
853 }
854 #endif /* PPS_SYNC */
855 #endif /* NTP */
856 #else /* !__HAVE_TIMECOUNTER */
857 /******************************************************************************
858 * *
859 * Copyright (c) David L. Mills 1993, 1994 *
860 * *
861 * Permission to use, copy, modify, and distribute this software and its *
862 * documentation for any purpose and without fee is hereby granted, provided *
863 * that the above copyright notice appears in all copies and that both the *
864 * copyright notice and this permission notice appear in supporting *
865 * documentation, and that the name University of Delaware not be used in *
866 * advertising or publicity pertaining to distribution of the software *
867 * without specific, written prior permission. The University of Delaware *
868 * makes no representations about the suitability this software for any *
869 * purpose. It is provided "as is" without express or implied warranty. *
870 * *
871 ******************************************************************************/
872
873 /*
874 * Modification history kern_ntptime.c
875 *
876 * 24 Sep 94 David L. Mills
877 * Tightened code at exits.
878 *
879 * 24 Mar 94 David L. Mills
880 * Revised syscall interface to include new variables for PPS
881 * time discipline.
882 *
883 * 14 Feb 94 David L. Mills
884 * Added code for external clock
885 *
886 * 28 Nov 93 David L. Mills
887 * Revised frequency scaling to conform with adjusted parameters
888 *
889 * 17 Sep 93 David L. Mills
890 * Created file
891 */
892 /*
893 * ntp_gettime(), ntp_adjtime() - precision time interface for SunOS
894 * V4.1.1 and V4.1.3
895 *
896 * These routines consitute the Network Time Protocol (NTP) interfaces
897 * for user and daemon application programs. The ntp_gettime() routine
898 * provides the time, maximum error (synch distance) and estimated error
899 * (dispersion) to client user application programs. The ntp_adjtime()
900 * routine is used by the NTP daemon to adjust the system clock to an
901 * externally derived time. The time offset and related variables set by
902 * this routine are used by hardclock() to adjust the phase and
903 * frequency of the phase-lock loop which controls the system clock.
904 */
905
906 #include <sys/cdefs.h>
907 __KERNEL_RCSID(0, "$NetBSD: kern_ntptime.c,v 1.41 2006/11/01 10:17:58 yamt Exp $");
908
909 #include "opt_ntp.h"
910 #include "opt_compat_netbsd.h"
911
912 #include <sys/param.h>
913 #include <sys/resourcevar.h>
914 #include <sys/systm.h>
915 #include <sys/kernel.h>
916 #include <sys/proc.h>
917 #include <sys/sysctl.h>
918 #include <sys/timex.h>
919 #ifdef COMPAT_30
920 #include <compat/sys/timex.h>
921 #endif
922 #include <sys/vnode.h>
923 #include <sys/kauth.h>
924
925 #include <sys/mount.h>
926 #include <sys/sa.h>
927 #include <sys/syscallargs.h>
928
929 #include <machine/cpu.h>
930
931 #ifdef NTP
932 /*
933 * The following variables are used by the hardclock() routine in the
934 * kern_clock.c module and are described in that module.
935 */
936 extern int time_state; /* clock state */
937 extern int time_status; /* clock status bits */
938 extern long time_offset; /* time adjustment (us) */
939 extern long time_freq; /* frequency offset (scaled ppm) */
940 extern long time_maxerror; /* maximum error (us) */
941 extern long time_esterror; /* estimated error (us) */
942 extern long time_constant; /* pll time constant */
943 extern long time_precision; /* clock precision (us) */
944 extern long time_tolerance; /* frequency tolerance (scaled ppm) */
945 extern int time_adjusted; /* ntp might have changed the system time */
946
947 #ifdef PPS_SYNC
948 /*
949 * The following variables are used only if the PPS signal discipline
950 * is configured in the kernel.
951 */
952 extern int pps_shift; /* interval duration (s) (shift) */
953 extern long pps_freq; /* pps frequency offset (scaled ppm) */
954 extern long pps_jitter; /* pps jitter (us) */
955 extern long pps_stabil; /* pps stability (scaled ppm) */
956 extern long pps_jitcnt; /* jitter limit exceeded */
957 extern long pps_calcnt; /* calibration intervals */
958 extern long pps_errcnt; /* calibration errors */
959 extern long pps_stbcnt; /* stability limit exceeded */
960 #endif /* PPS_SYNC */
961
962 /*ARGSUSED*/
963 /*
964 * ntp_gettime() - NTP user application interface
965 */
966 void
967 ntp_gettime(ntvp)
968 struct ntptimeval *ntvp;
969 {
970 struct timeval atv;
971 int s;
972
973 memset(ntvp, 0, sizeof(struct ntptimeval));
974
975 s = splclock();
976 #ifdef EXT_CLOCK
977 /*
978 * The microtime() external clock routine returns a
979 * status code. If less than zero, we declare an error
980 * in the clock status word and return the kernel
981 * (software) time variable. While there are other
982 * places that call microtime(), this is the only place
983 * that matters from an application point of view.
984 */
985 if (microtime(&atv) < 0) {
986 time_status |= STA_CLOCKERR;
987 ntvp->time = time;
988 } else
989 time_status &= ~STA_CLOCKERR;
990 #else /* EXT_CLOCK */
991 microtime(&atv);
992 #endif /* EXT_CLOCK */
993 ntvp->maxerror = time_maxerror;
994 ntvp->esterror = time_esterror;
995 (void) splx(s);
996 TIMEVAL_TO_TIMESPEC(&atv, &ntvp->time);
997 }
998
999
1000 /* ARGSUSED */
1001 /*
1002 * ntp_adjtime() - NTP daemon application interface
1003 */
1004 int
1005 sys_ntp_adjtime(l, v, retval)
1006 struct lwp *l;
1007 void *v;
1008 register_t *retval;
1009 {
1010 struct sys_ntp_adjtime_args /* {
1011 syscallarg(struct timex *) tp;
1012 } */ *uap = v;
1013 struct timex ntv;
1014 int error = 0;
1015
1016 error = copyin((caddr_t)SCARG(uap, tp), (caddr_t)&ntv, sizeof(ntv));
1017 if (error != 0)
1018 return (error);
1019
1020 if (ntv.modes != 0 && (error = kauth_authorize_system(l->l_cred,
1021 KAUTH_SYSTEM_TIME, KAUTH_REQ_SYSTEM_TIME_NTPADJTIME, NULL,
1022 NULL, NULL)) != 0)
1023 return (error);
1024
1025 ntp_adjtime1(&ntv);
1026
1027 error = copyout((caddr_t)&ntv, (caddr_t)SCARG(uap, tp), sizeof(ntv));
1028 if (error == 0)
1029 *retval = ntp_timestatus();
1030
1031 return error;
1032 }
1033
1034 void
1035 ntp_adjtime1(ntv)
1036 struct timex *ntv;
1037 {
1038 int modes;
1039 int s;
1040
1041 /*
1042 * Update selected clock variables. Note that there is no error
1043 * checking here on the assumption the superuser should know
1044 * what it is doing.
1045 */
1046 modes = ntv->modes;
1047 if (modes != 0)
1048 /* We need to save the system time during shutdown */
1049 time_adjusted |= 2;
1050 s = splclock();
1051 if (modes & MOD_FREQUENCY)
1052 #ifdef PPS_SYNC
1053 time_freq = ntv->freq - pps_freq;
1054 #else /* PPS_SYNC */
1055 time_freq = ntv->freq;
1056 #endif /* PPS_SYNC */
1057 if (modes & MOD_MAXERROR)
1058 time_maxerror = ntv->maxerror;
1059 if (modes & MOD_ESTERROR)
1060 time_esterror = ntv->esterror;
1061 if (modes & MOD_STATUS) {
1062 time_status &= STA_RONLY;
1063 time_status |= ntv->status & ~STA_RONLY;
1064 }
1065 if (modes & MOD_TIMECONST)
1066 time_constant = ntv->constant;
1067 if (modes & MOD_OFFSET)
1068 hardupdate(ntv->offset);
1069
1070 /*
1071 * Retrieve all clock variables
1072 */
1073 if (time_offset < 0)
1074 ntv->offset = -(-time_offset >> SHIFT_UPDATE);
1075 else
1076 ntv->offset = time_offset >> SHIFT_UPDATE;
1077 #ifdef PPS_SYNC
1078 ntv->freq = time_freq + pps_freq;
1079 #else /* PPS_SYNC */
1080 ntv->freq = time_freq;
1081 #endif /* PPS_SYNC */
1082 ntv->maxerror = time_maxerror;
1083 ntv->esterror = time_esterror;
1084 ntv->status = time_status;
1085 ntv->constant = time_constant;
1086 ntv->precision = time_precision;
1087 ntv->tolerance = time_tolerance;
1088 #ifdef PPS_SYNC
1089 ntv->shift = pps_shift;
1090 ntv->ppsfreq = pps_freq;
1091 ntv->jitter = pps_jitter >> PPS_AVG;
1092 ntv->stabil = pps_stabil;
1093 ntv->calcnt = pps_calcnt;
1094 ntv->errcnt = pps_errcnt;
1095 ntv->jitcnt = pps_jitcnt;
1096 ntv->stbcnt = pps_stbcnt;
1097 #endif /* PPS_SYNC */
1098 (void)splx(s);
1099 }
1100 #endif /* NTP */
1101 #endif /* !__HAVE_TIMECOUNTER */
1102
1103 #ifdef NTP
1104 int
1105 ntp_timestatus()
1106 {
1107 /*
1108 * Status word error decode. If any of these conditions
1109 * occur, an error is returned, instead of the status
1110 * word. Most applications will care only about the fact
1111 * the system clock may not be trusted, not about the
1112 * details.
1113 *
1114 * Hardware or software error
1115 */
1116 if ((time_status & (STA_UNSYNC | STA_CLOCKERR)) ||
1117
1118 /*
1119 * PPS signal lost when either time or frequency
1120 * synchronization requested
1121 */
1122 (time_status & (STA_PPSFREQ | STA_PPSTIME) &&
1123 !(time_status & STA_PPSSIGNAL)) ||
1124
1125 /*
1126 * PPS jitter exceeded when time synchronization
1127 * requested
1128 */
1129 (time_status & STA_PPSTIME &&
1130 time_status & STA_PPSJITTER) ||
1131
1132 /*
1133 * PPS wander exceeded or calibration error when
1134 * frequency synchronization requested
1135 */
1136 (time_status & STA_PPSFREQ &&
1137 time_status & (STA_PPSWANDER | STA_PPSERROR)))
1138 return (TIME_ERROR);
1139 else
1140 return (time_state);
1141 }
1142
1143 /*ARGSUSED*/
1144 /*
1145 * ntp_gettime() - NTP user application interface
1146 */
1147 int
1148 sys___ntp_gettime30(struct lwp *l, void *v, register_t *retval)
1149 {
1150 struct sys___ntp_gettime30_args /* {
1151 syscallarg(struct ntptimeval *) ntvp;
1152 } */ *uap = v;
1153 struct ntptimeval ntv;
1154 int error = 0;
1155
1156 if (SCARG(uap, ntvp)) {
1157 ntp_gettime(&ntv);
1158
1159 error = copyout((caddr_t)&ntv, (caddr_t)SCARG(uap, ntvp),
1160 sizeof(ntv));
1161 }
1162 if (!error) {
1163 *retval = ntp_timestatus();
1164 }
1165 return(error);
1166 }
1167
1168 #ifdef COMPAT_30
1169 int
1170 compat_30_sys_ntp_gettime(struct lwp *l, void *v, register_t *retval)
1171 {
1172 struct compat_30_sys_ntp_gettime_args /* {
1173 syscallarg(struct ntptimeval30 *) ontvp;
1174 } */ *uap = v;
1175 struct ntptimeval ntv;
1176 struct ntptimeval30 ontv;
1177 int error = 0;
1178
1179 if (SCARG(uap, ntvp)) {
1180 ntp_gettime(&ntv);
1181 TIMESPEC_TO_TIMEVAL(&ontv.time, &ntv.time);
1182 ontv.maxerror = ntv.maxerror;
1183 ontv.esterror = ntv.esterror;
1184
1185 error = copyout((caddr_t)&ontv, (caddr_t)SCARG(uap, ntvp),
1186 sizeof(ontv));
1187 }
1188 if (!error)
1189 *retval = ntp_timestatus();
1190
1191 return (error);
1192 }
1193 #endif
1194
1195 /*
1196 * return information about kernel precision timekeeping
1197 */
1198 static int
1199 sysctl_kern_ntptime(SYSCTLFN_ARGS)
1200 {
1201 struct sysctlnode node;
1202 struct ntptimeval ntv;
1203
1204 ntp_gettime(&ntv);
1205
1206 node = *rnode;
1207 node.sysctl_data = &ntv;
1208 node.sysctl_size = sizeof(ntv);
1209 return (sysctl_lookup(SYSCTLFN_CALL(&node)));
1210 }
1211
1212 SYSCTL_SETUP(sysctl_kern_ntptime_setup, "sysctl kern.ntptime node setup")
1213 {
1214
1215 sysctl_createv(clog, 0, NULL, NULL,
1216 CTLFLAG_PERMANENT,
1217 CTLTYPE_NODE, "kern", NULL,
1218 NULL, 0, NULL, 0,
1219 CTL_KERN, CTL_EOL);
1220
1221 sysctl_createv(clog, 0, NULL, NULL,
1222 CTLFLAG_PERMANENT,
1223 CTLTYPE_STRUCT, "ntptime",
1224 SYSCTL_DESCR("Kernel clock values for NTP"),
1225 sysctl_kern_ntptime, 0, NULL,
1226 sizeof(struct ntptimeval),
1227 CTL_KERN, KERN_NTPTIME, CTL_EOL);
1228 }
1229 #else /* !NTP */
1230 /* For some reason, raising SIGSYS (as sys_nosys would) is problematic. */
1231
1232 int
1233 sys___ntp_gettime30(struct lwp *l, void *v, register_t *retval)
1234 {
1235
1236 return(ENOSYS);
1237 }
1238
1239 #ifdef COMPAT_30
1240 int
1241 compat_30_sys_ntp_gettime(struct lwp *l, void *v, register_t *retval)
1242 {
1243
1244 return(ENOSYS);
1245 }
1246 #endif
1247 #endif /* !NTP */
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