1/*- 2 *********************************************************************** 3 * * 4 * Copyright (c) David L. Mills 1993-2001 * 5 * * 6 * Permission to use, copy, modify, and distribute this software and * 7 * its documentation for any purpose and without fee is hereby * 8 * granted, provided that the above copyright notice appears in all * 9 * copies and that both the copyright notice and this permission * 10 * notice appear in supporting documentation, and that the name * 11 * University of Delaware not be used in advertising or publicity * 12 * pertaining to distribution of the software without specific, * 13 * written prior permission. The University of Delaware makes no * 14 * representations about the suitability this software for any * 15 * purpose. It is provided "as is" without express or implied * 16 * warranty. * 17 * * 18 **********************************************************************/ 19 20/* 21 * Adapted from the original sources for FreeBSD and timecounters by: 22 * Poul-Henning Kamp <phk@FreeBSD.org>. 23 * 24 * The 32bit version of the "LP" macros seems a bit past its "sell by" 25 * date so I have retained only the 64bit version and included it directly 26 * in this file. 27 * 28 * Only minor changes done to interface with the timecounters over in 29 * sys/kern/kern_clock.c. Some of the comments below may be (even more) 30 * confusing and/or plain wrong in that context. 31 */ 32 33#include <sys/cdefs.h> 34#include "opt_ntp.h" 35 36#include <sys/param.h> 37#include <sys/systm.h> 38#include <sys/sysproto.h> 39#include <sys/eventhandler.h> 40#include <sys/kernel.h> 41#include <sys/priv.h> 42#include <sys/proc.h> 43#include <sys/lock.h> 44#include <sys/mutex.h> 45#include <sys/time.h> 46#include <sys/timex.h> 47#include <sys/timetc.h> 48#include <sys/timepps.h> 49#include <sys/syscallsubr.h> 50#include <sys/sysctl.h> 51 52#ifdef PPS_SYNC 53FEATURE(pps_sync, "Support usage of external PPS signal by kernel PLL"); 54#endif 55 56/* 57 * Single-precision macros for 64-bit machines 58 */ 59typedef int64_t l_fp; 60#define L_ADD(v, u) ((v) += (u)) 61#define L_SUB(v, u) ((v) -= (u)) 62#define L_ADDHI(v, a) ((v) += (int64_t)(a) << 32) 63#define L_NEG(v) ((v) = -(v)) 64#define L_RSHIFT(v, n) \ 65 do { \ 66 if ((v) < 0) \ 67 (v) = -(-(v) >> (n)); \ 68 else \ 69 (v) = (v) >> (n); \ 70 } while (0) 71#define L_MPY(v, a) ((v) *= (a)) 72#define L_CLR(v) ((v) = 0) 73#define L_ISNEG(v) ((v) < 0) 74#define L_LINT(v, a) \ 75 do { \ 76 if ((a) < 0) \ 77 ((v) = -((int64_t)(-(a)) << 32)); \ 78 else \ 79 ((v) = (int64_t)(a) << 32); \ 80 } while (0) 81#define L_GINT(v) ((v) < 0 ? -(-(v) >> 32) : (v) >> 32) 82 83/* 84 * Generic NTP kernel interface 85 * 86 * These routines constitute the Network Time Protocol (NTP) interfaces 87 * for user and daemon application programs. The ntp_gettime() routine 88 * provides the time, maximum error (synch distance) and estimated error 89 * (dispersion) to client user application programs. The ntp_adjtime() 90 * routine is used by the NTP daemon to adjust the system clock to an 91 * externally derived time. The time offset and related variables set by 92 * this routine are used by other routines in this module to adjust the 93 * phase and frequency of the clock discipline loop which controls the 94 * system clock. 95 * 96 * When the kernel time is reckoned directly in nanoseconds (NTP_NANO 97 * defined), the time at each tick interrupt is derived directly from 98 * the kernel time variable. When the kernel time is reckoned in 99 * microseconds, (NTP_NANO undefined), the time is derived from the 100 * kernel time variable together with a variable representing the 101 * leftover nanoseconds at the last tick interrupt. In either case, the 102 * current nanosecond time is reckoned from these values plus an 103 * interpolated value derived by the clock routines in another 104 * architecture-specific module. The interpolation can use either a 105 * dedicated counter or a processor cycle counter (PCC) implemented in 106 * some architectures. 107 * 108 * Note that all routines must run at priority splclock or higher. 109 */ 110/* 111 * Phase/frequency-lock loop (PLL/FLL) definitions 112 * 113 * The nanosecond clock discipline uses two variable types, time 114 * variables and frequency variables. Both types are represented as 64- 115 * bit fixed-point quantities with the decimal point between two 32-bit 116 * halves. On a 32-bit machine, each half is represented as a single 117 * word and mathematical operations are done using multiple-precision 118 * arithmetic. On a 64-bit machine, ordinary computer arithmetic is 119 * used. 120 * 121 * A time variable is a signed 64-bit fixed-point number in ns and 122 * fraction. It represents the remaining time offset to be amortized 123 * over succeeding tick interrupts. The maximum time offset is about 124 * 0.5 s and the resolution is about 2.3e-10 ns. 125 * 126 * 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 127 * 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 1 128 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 129 * |s s s| ns | 130 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 131 * | fraction | 132 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 133 * 134 * A frequency variable is a signed 64-bit fixed-point number in ns/s 135 * and fraction. It represents the ns and fraction to be added to the 136 * kernel time variable at each second. The maximum frequency offset is 137 * about +-500000 ns/s and the resolution is about 2.3e-10 ns/s. 138 * 139 * 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 140 * 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 1 141 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 142 * |s s s s s s s s s s s s s| ns/s | 143 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 144 * | fraction | 145 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 146 */ 147/* 148 * The following variables establish the state of the PLL/FLL and the 149 * residual time and frequency offset of the local clock. 150 */ 151#define SHIFT_PLL 4 /* PLL loop gain (shift) */ 152#define SHIFT_FLL 2 /* FLL loop gain (shift) */ 153 154static int time_state = TIME_OK; /* clock state */ 155int time_status = STA_UNSYNC; /* clock status bits */ 156static long time_tai; /* TAI offset (s) */ 157static long time_monitor; /* last time offset scaled (ns) */ 158static long time_constant; /* poll interval (shift) (s) */ 159static long time_precision = 1; /* clock precision (ns) */ 160static long time_maxerror = MAXPHASE / 1000; /* maximum error (us) */ 161long time_esterror = MAXPHASE / 1000; /* estimated error (us) */ 162static long time_reftime; /* uptime at last adjustment (s) */ 163static l_fp time_offset; /* time offset (ns) */ 164static l_fp time_freq; /* frequency offset (ns/s) */ 165static l_fp time_adj; /* tick adjust (ns/s) */ 166 167static int64_t time_adjtime; /* correction from adjtime(2) (usec) */ 168 169static struct mtx ntp_lock; 170MTX_SYSINIT(ntp, &ntp_lock, "ntp", MTX_SPIN); 171 172#define NTP_LOCK() mtx_lock_spin(&ntp_lock) 173#define NTP_UNLOCK() mtx_unlock_spin(&ntp_lock) 174#define NTP_ASSERT_LOCKED() mtx_assert(&ntp_lock, MA_OWNED) 175 176#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 191static struct timespec pps_tf[3]; /* phase median filter */ 192static l_fp pps_freq; /* scaled frequency offset (ns/s) */ 193static long pps_fcount; /* frequency accumulator */ 194static long pps_jitter; /* nominal jitter (ns) */ 195static long pps_stabil; /* nominal stability (scaled ns/s) */ 196static long pps_lastsec; /* time at last calibration (s) */ 197static int pps_valid; /* signal watchdog counter */ 198static int pps_shift = PPS_FAVG; /* interval duration (s) (shift) */ 199static int pps_shiftmax = PPS_FAVGDEF; /* max interval duration (s) (shift) */ 200static int pps_intcnt; /* wander counter */ 201 202/* 203 * PPS signal quality monitors 204 */ 205static long pps_calcnt; /* calibration intervals */ 206static long pps_jitcnt; /* jitter limit exceeded */ 207static long pps_stbcnt; /* stability limit exceeded */ 208static long pps_errcnt; /* calibration errors */ 209#endif /* PPS_SYNC */ 210/* 211 * End of phase/frequency-lock loop (PLL/FLL) definitions 212 */ 213 214static void hardupdate(long offset); 215static void ntp_gettime1(struct ntptimeval *ntvp); 216static bool ntp_is_time_error(int tsl); 217 218static bool 219ntp_is_time_error(int tsl) 220{ 221 222 /* 223 * Status word error decode. If any of these conditions occur, 224 * an error is returned, instead of the status word. Most 225 * applications will care only about the fact the system clock 226 * may not be trusted, not about the details. 227 * 228 * Hardware or software error 229 */ 230 if ((tsl & (STA_UNSYNC | STA_CLOCKERR)) || 231 232 /* 233 * PPS signal lost when either time or frequency synchronization 234 * requested 235 */ 236 (tsl & (STA_PPSFREQ | STA_PPSTIME) && 237 !(tsl & STA_PPSSIGNAL)) || 238 239 /* 240 * PPS jitter exceeded when time synchronization requested 241 */ 242 (tsl & STA_PPSTIME && tsl & STA_PPSJITTER) || 243 244 /* 245 * PPS wander exceeded or calibration error when frequency 246 * synchronization requested 247 */ 248 (tsl & STA_PPSFREQ && 249 tsl & (STA_PPSWANDER | STA_PPSERROR))) 250 return (true); 251 252 return (false); 253} 254 255static void 256ntp_gettime1(struct ntptimeval *ntvp) 257{ 258 struct timespec atv; /* nanosecond time */ 259 260 NTP_ASSERT_LOCKED(); 261 262 nanotime(&atv); 263 ntvp->time.tv_sec = atv.tv_sec; 264 ntvp->time.tv_nsec = atv.tv_nsec; 265 ntvp->maxerror = time_maxerror; 266 ntvp->esterror = time_esterror; 267 ntvp->tai = time_tai; 268 ntvp->time_state = time_state; 269 270 if (ntp_is_time_error(time_status)) 271 ntvp->time_state = TIME_ERROR; 272} 273 274/* 275 * ntp_gettime() - NTP user application interface 276 * 277 * See the timex.h header file for synopsis and API description. Note that 278 * the TAI offset is returned in the ntvtimeval.tai structure member. 279 */ 280#ifndef _SYS_SYSPROTO_H_ 281struct ntp_gettime_args { 282 struct ntptimeval *ntvp; 283}; 284#endif 285/* ARGSUSED */ 286int 287sys_ntp_gettime(struct thread *td, struct ntp_gettime_args *uap) 288{ 289 struct ntptimeval ntv; 290 291 memset(&ntv, 0, sizeof(ntv)); 292 293 NTP_LOCK(); 294 ntp_gettime1(&ntv); 295 NTP_UNLOCK(); 296 297 td->td_retval[0] = ntv.time_state; 298 return (copyout(&ntv, uap->ntvp, sizeof(ntv))); 299} 300 301static int 302ntp_sysctl(SYSCTL_HANDLER_ARGS) 303{ 304 struct ntptimeval ntv; /* temporary structure */ 305 306 memset(&ntv, 0, sizeof(ntv)); 307 308 NTP_LOCK(); 309 ntp_gettime1(&ntv); 310 NTP_UNLOCK(); 311 312 return (sysctl_handle_opaque(oidp, &ntv, sizeof(ntv), req)); 313} 314 315SYSCTL_NODE(_kern, OID_AUTO, ntp_pll, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 316 ""); 317SYSCTL_PROC(_kern_ntp_pll, OID_AUTO, gettime, CTLTYPE_OPAQUE | CTLFLAG_RD | 318 CTLFLAG_MPSAFE, 0, sizeof(struct ntptimeval) , ntp_sysctl, "S,ntptimeval", 319 ""); 320 321#ifdef PPS_SYNC 322SYSCTL_INT(_kern_ntp_pll, OID_AUTO, pps_shiftmax, CTLFLAG_RW, 323 &pps_shiftmax, 0, "Max interval duration (sec) (shift)"); 324SYSCTL_INT(_kern_ntp_pll, OID_AUTO, pps_shift, CTLFLAG_RW, 325 &pps_shift, 0, "Interval duration (sec) (shift)"); 326SYSCTL_LONG(_kern_ntp_pll, OID_AUTO, time_monitor, CTLFLAG_RD, 327 &time_monitor, 0, "Last time offset scaled (ns)"); 328 329SYSCTL_S64(_kern_ntp_pll, OID_AUTO, pps_freq, CTLFLAG_RD | CTLFLAG_MPSAFE, 330 &pps_freq, 0, 331 "Scaled frequency offset (ns/sec)"); 332SYSCTL_S64(_kern_ntp_pll, OID_AUTO, time_freq, CTLFLAG_RD | CTLFLAG_MPSAFE, 333 &time_freq, 0, 334 "Frequency offset (ns/sec)"); 335#endif 336 337/* 338 * ntp_adjtime() - NTP daemon application interface 339 * 340 * See the timex.h header file for synopsis and API description. Note that 341 * the timex.constant structure member has a dual purpose to set the time 342 * constant and to set the TAI offset. 343 */ 344int 345kern_ntp_adjtime(struct thread *td, struct timex *ntv, int *retvalp) 346{ 347 long freq; /* frequency ns/s) */ 348 int modes; /* mode bits from structure */ 349 int error, retval; 350 351 /* 352 * Update selected clock variables - only the superuser can 353 * change anything. Note that there is no error checking here on 354 * the assumption the superuser should know what it is doing. 355 * Note that either the time constant or TAI offset are loaded 356 * from the ntv.constant member, depending on the mode bits. If 357 * the STA_PLL bit in the status word is cleared, the state and 358 * status words are reset to the initial values at boot. 359 */ 360 modes = ntv->modes; 361 error = 0; 362 if (modes) 363 error = priv_check(td, PRIV_NTP_ADJTIME); 364 if (error != 0) 365 return (error); 366 NTP_LOCK(); 367 if (modes & MOD_MAXERROR) 368 time_maxerror = ntv->maxerror; 369 if (modes & MOD_ESTERROR) 370 time_esterror = ntv->esterror; 371 if (modes & MOD_STATUS) { 372 if (time_status & STA_PLL && !(ntv->status & STA_PLL)) { 373 time_state = TIME_OK; 374 time_status = STA_UNSYNC; 375#ifdef PPS_SYNC 376 pps_shift = PPS_FAVG; 377#endif /* PPS_SYNC */ 378 } 379 time_status &= STA_RONLY; 380 time_status |= ntv->status & ~STA_RONLY; 381 } 382 if (modes & MOD_TIMECONST) { 383 if (ntv->constant < 0) 384 time_constant = 0; 385 else if (ntv->constant > MAXTC) 386 time_constant = MAXTC; 387 else 388 time_constant = ntv->constant; 389 } 390 if (modes & MOD_TAI) { 391 if (ntv->constant > 0) /* XXX zero & negative numbers ? */ 392 time_tai = ntv->constant; 393 } 394#ifdef PPS_SYNC 395 if (modes & MOD_PPSMAX) { 396 if (ntv->shift < PPS_FAVG) 397 pps_shiftmax = PPS_FAVG; 398 else if (ntv->shift > PPS_FAVGMAX) 399 pps_shiftmax = PPS_FAVGMAX; 400 else 401 pps_shiftmax = ntv->shift; 402 } 403#endif /* PPS_SYNC */ 404 if (modes & MOD_NANO) 405 time_status |= STA_NANO; 406 if (modes & MOD_MICRO) 407 time_status &= ~STA_NANO; 408 if (modes & MOD_CLKB) 409 time_status |= STA_CLK; 410 if (modes & MOD_CLKA) 411 time_status &= ~STA_CLK; 412 if (modes & MOD_FREQUENCY) { 413 freq = (ntv->freq * 1000LL) >> 16; 414 if (freq > MAXFREQ) 415 L_LINT(time_freq, MAXFREQ); 416 else if (freq < -MAXFREQ) 417 L_LINT(time_freq, -MAXFREQ); 418 else { 419 /* 420 * ntv->freq is [PPM * 2^16] = [us/s * 2^16] 421 * time_freq is [ns/s * 2^32] 422 */ 423 time_freq = ntv->freq * 1000LL * 65536LL; 424 } 425#ifdef PPS_SYNC 426 pps_freq = time_freq; 427#endif /* PPS_SYNC */ 428 } 429 if (modes & MOD_OFFSET) { 430 if (time_status & STA_NANO) 431 hardupdate(ntv->offset); 432 else 433 hardupdate(ntv->offset * 1000); 434 } 435 436 /* 437 * Retrieve all clock variables. Note that the TAI offset is 438 * returned only by ntp_gettime(); 439 */ 440 if (time_status & STA_NANO) 441 ntv->offset = L_GINT(time_offset); 442 else 443 ntv->offset = L_GINT(time_offset) / 1000; /* XXX rounding ? */ 444 ntv->freq = L_GINT((time_freq / 1000LL) << 16); 445 ntv->maxerror = time_maxerror; 446 ntv->esterror = time_esterror; 447 ntv->status = time_status; 448 ntv->constant = time_constant; 449 if (time_status & STA_NANO) 450 ntv->precision = time_precision; 451 else 452 ntv->precision = time_precision / 1000; 453 ntv->tolerance = MAXFREQ * SCALE_PPM; 454#ifdef PPS_SYNC 455 ntv->shift = pps_shift; 456 ntv->ppsfreq = L_GINT((pps_freq / 1000LL) << 16); 457 if (time_status & STA_NANO) 458 ntv->jitter = pps_jitter; 459 else 460 ntv->jitter = pps_jitter / 1000; 461 ntv->stabil = pps_stabil; 462 ntv->calcnt = pps_calcnt; 463 ntv->errcnt = pps_errcnt; 464 ntv->jitcnt = pps_jitcnt; 465 ntv->stbcnt = pps_stbcnt; 466#endif /* PPS_SYNC */ 467 retval = ntp_is_time_error(time_status) ? TIME_ERROR : time_state; 468 NTP_UNLOCK(); 469 470 *retvalp = retval; 471 return (0); 472} 473 474#ifndef _SYS_SYSPROTO_H_ 475struct ntp_adjtime_args { 476 struct timex *tp; 477}; 478#endif 479 480int 481sys_ntp_adjtime(struct thread *td, struct ntp_adjtime_args *uap) 482{ 483 struct timex ntv; 484 int error, retval; 485 486 error = copyin(uap->tp, &ntv, sizeof(ntv)); 487 if (error == 0) { 488 error = kern_ntp_adjtime(td, &ntv, &retval); 489 if (error == 0) { 490 error = copyout(&ntv, uap->tp, sizeof(ntv)); 491 if (error == 0) 492 td->td_retval[0] = retval; 493 } 494 } 495 return (error); 496} 497 498/* 499 * second_overflow() - called after ntp_tick_adjust() 500 * 501 * This routine is ordinarily called immediately following the above 502 * routine ntp_tick_adjust(). While these two routines are normally 503 * combined, they are separated here only for the purposes of 504 * simulation. 505 */ 506void 507ntp_update_second(int64_t *adjustment, time_t *newsec) 508{ 509 int tickrate; 510 l_fp ftemp; /* 32/64-bit temporary */ 511 512 NTP_LOCK(); 513 514 /* 515 * On rollover of the second both the nanosecond and microsecond 516 * clocks are updated and the state machine cranked as 517 * necessary. The phase adjustment to be used for the next 518 * second is calculated and the maximum error is increased by 519 * the tolerance. 520 */ 521 time_maxerror += MAXFREQ / 1000; 522 523 /* 524 * Leap second processing. If in leap-insert state at 525 * the end of the day, the system clock is set back one 526 * second; if in leap-delete state, the system clock is 527 * set ahead one second. The nano_time() routine or 528 * external clock driver will insure that reported time 529 * is always monotonic. 530 */ 531 switch (time_state) { 532 /* 533 * No warning. 534 */ 535 case TIME_OK: 536 if (time_status & STA_INS) 537 time_state = TIME_INS; 538 else if (time_status & STA_DEL) 539 time_state = TIME_DEL; 540 break; 541 542 /* 543 * Insert second 23:59:60 following second 544 * 23:59:59. 545 */ 546 case TIME_INS: 547 if (!(time_status & STA_INS)) 548 time_state = TIME_OK; 549 else if ((*newsec) % 86400 == 0) { 550 (*newsec)--; 551 time_state = TIME_OOP; 552 time_tai++; 553 } 554 break; 555 556 /* 557 * Delete second 23:59:59. 558 */ 559 case TIME_DEL: 560 if (!(time_status & STA_DEL)) 561 time_state = TIME_OK; 562 else if (((*newsec) + 1) % 86400 == 0) { 563 (*newsec)++; 564 time_tai--; 565 time_state = TIME_WAIT; 566 } 567 break; 568 569 /* 570 * Insert second in progress. 571 */ 572 case TIME_OOP: 573 time_state = TIME_WAIT; 574 break; 575 576 /* 577 * Wait for status bits to clear. 578 */ 579 case TIME_WAIT: 580 if (!(time_status & (STA_INS | STA_DEL))) 581 time_state = TIME_OK; 582 } 583 584 /* 585 * Compute the total time adjustment for the next second 586 * in ns. The offset is reduced by a factor depending on 587 * whether the PPS signal is operating. Note that the 588 * value is in effect scaled by the clock frequency, 589 * since the adjustment is added at each tick interrupt. 590 */ 591 ftemp = time_offset; 592#ifdef PPS_SYNC 593 /* XXX even if PPS signal dies we should finish adjustment ? */ 594 if (time_status & STA_PPSTIME && time_status & 595 STA_PPSSIGNAL) 596 L_RSHIFT(ftemp, pps_shift); 597 else 598 L_RSHIFT(ftemp, SHIFT_PLL + time_constant); 599#else 600 L_RSHIFT(ftemp, SHIFT_PLL + time_constant); 601#endif /* PPS_SYNC */ 602 time_adj = ftemp; 603 L_SUB(time_offset, ftemp); 604 L_ADD(time_adj, time_freq); 605 606 /* 607 * Apply any correction from adjtime(2). If more than one second 608 * off we slew at a rate of 5ms/s (5000 PPM) else 500us/s (500 PPM) 609 * until the last second is slewed the final < 500 usecs. 610 */ 611 if (time_adjtime != 0) { 612 if (time_adjtime > 1000000) 613 tickrate = 5000; 614 else if (time_adjtime < -1000000) 615 tickrate = -5000; 616 else if (time_adjtime > 500) 617 tickrate = 500; 618 else if (time_adjtime < -500) 619 tickrate = -500; 620 else 621 tickrate = time_adjtime; 622 time_adjtime -= tickrate; 623 L_LINT(ftemp, tickrate * 1000); 624 L_ADD(time_adj, ftemp); 625 } 626 *adjustment = time_adj; 627 628#ifdef PPS_SYNC 629 if (pps_valid > 0) 630 pps_valid--; 631 else 632 time_status &= ~STA_PPSSIGNAL; 633#endif /* PPS_SYNC */ 634 635 NTP_UNLOCK(); 636} 637 638/* 639 * hardupdate() - local clock update 640 * 641 * This routine is called by ntp_adjtime() to update the local clock 642 * phase and frequency. The implementation is of an adaptive-parameter, 643 * hybrid phase/frequency-lock loop (PLL/FLL). The routine computes new 644 * time and frequency offset estimates for each call. If the kernel PPS 645 * discipline code is configured (PPS_SYNC), the PPS signal itself 646 * determines the new time offset, instead of the calling argument. 647 * Presumably, calls to ntp_adjtime() occur only when the caller 648 * believes the local clock is valid within some bound (+-128 ms with 649 * NTP). If the caller's time is far different than the PPS time, an 650 * argument will ensue, and it's not clear who will lose. 651 * 652 * For uncompensated quartz crystal oscillators and nominal update 653 * intervals less than 256 s, operation should be in phase-lock mode, 654 * where the loop is disciplined to phase. For update intervals greater 655 * than 1024 s, operation should be in frequency-lock mode, where the 656 * loop is disciplined to frequency. Between 256 s and 1024 s, the mode 657 * is selected by the STA_MODE status bit. 658 */ 659static void 660hardupdate(long offset /* clock offset (ns) */) 661{ 662 long mtemp; 663 l_fp ftemp; 664 665 NTP_ASSERT_LOCKED(); 666 667 /* 668 * Select how the phase is to be controlled and from which 669 * source. If the PPS signal is present and enabled to 670 * discipline the time, the PPS offset is used; otherwise, the 671 * argument offset is used. 672 */ 673 if (!(time_status & STA_PLL)) 674 return; 675 if (!(time_status & STA_PPSTIME && time_status & 676 STA_PPSSIGNAL)) { 677 if (offset > MAXPHASE) 678 time_monitor = MAXPHASE; 679 else if (offset < -MAXPHASE) 680 time_monitor = -MAXPHASE; 681 else 682 time_monitor = offset; 683 L_LINT(time_offset, time_monitor); 684 } 685 686 /* 687 * Select how the frequency is to be controlled and in which 688 * mode (PLL or FLL). If the PPS signal is present and enabled 689 * to discipline the frequency, the PPS frequency is used; 690 * otherwise, the argument offset is used to compute it. 691 */ 692 if (time_status & STA_PPSFREQ && time_status & STA_PPSSIGNAL) { 693 time_reftime = time_uptime; 694 return; 695 } 696 if (time_status & STA_FREQHOLD || time_reftime == 0) 697 time_reftime = time_uptime; 698 mtemp = time_uptime - time_reftime; 699 L_LINT(ftemp, time_monitor); 700 L_RSHIFT(ftemp, (SHIFT_PLL + 2 + time_constant) << 1); 701 L_MPY(ftemp, mtemp); 702 L_ADD(time_freq, ftemp); 703 time_status &= ~STA_MODE; 704 if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > 705 MAXSEC)) { 706 L_LINT(ftemp, (time_monitor << 4) / mtemp); 707 L_RSHIFT(ftemp, SHIFT_FLL + 4); 708 L_ADD(time_freq, ftemp); 709 time_status |= STA_MODE; 710 } 711 time_reftime = time_uptime; 712 if (L_GINT(time_freq) > MAXFREQ) 713 L_LINT(time_freq, MAXFREQ); 714 else if (L_GINT(time_freq) < -MAXFREQ) 715 L_LINT(time_freq, -MAXFREQ); 716} 717 718#ifdef PPS_SYNC 719/* 720 * hardpps() - discipline CPU clock oscillator to external PPS signal 721 * 722 * This routine is called at each PPS interrupt in order to discipline 723 * the CPU clock oscillator to the PPS signal. There are two independent 724 * first-order feedback loops, one for the phase, the other for the 725 * frequency. The phase loop measures and grooms the PPS phase offset 726 * and leaves it in a handy spot for the seconds overflow routine. The 727 * frequency loop averages successive PPS phase differences and 728 * calculates the PPS frequency offset, which is also processed by the 729 * seconds overflow routine. The code requires the caller to capture the 730 * time and architecture-dependent hardware counter values in 731 * nanoseconds at the on-time PPS signal transition. 732 * 733 * Note that, on some Unix systems this routine runs at an interrupt 734 * priority level higher than the timer interrupt routine hardclock(). 735 * Therefore, the variables used are distinct from the hardclock() 736 * variables, except for the actual time and frequency variables, which 737 * are determined by this routine and updated atomically. 738 * 739 * tsp - time at current PPS event 740 * delta_nsec - time elapsed between the previous and current PPS event 741 */ 742void 743hardpps(struct timespec *tsp, long delta_nsec) 744{ 745 long u_sec, u_nsec, v_nsec; /* temps */ 746 l_fp ftemp; 747 748 NTP_LOCK(); 749 750 /* 751 * The signal is first processed by a range gate and frequency 752 * discriminator. The range gate rejects noise spikes outside 753 * the range +-500 us. The frequency discriminator rejects input 754 * signals with apparent frequency outside the range 1 +-500 755 * PPM. If two hits occur in the same second, we ignore the 756 * later hit; if not and a hit occurs outside the range gate, 757 * keep the later hit for later comparison, but do not process 758 * it. 759 */ 760 time_status |= STA_PPSSIGNAL | STA_PPSJITTER; 761 time_status &= ~(STA_PPSWANDER | STA_PPSERROR); 762 pps_valid = PPS_VALID; 763 u_sec = tsp->tv_sec; 764 u_nsec = tsp->tv_nsec; 765 if (u_nsec >= (NANOSECOND >> 1)) { 766 u_nsec -= NANOSECOND; 767 u_sec++; 768 } 769 v_nsec = u_nsec - pps_tf[0].tv_nsec; 770 if (u_sec == pps_tf[0].tv_sec && v_nsec < NANOSECOND - MAXFREQ) 771 goto out; 772 pps_tf[2] = pps_tf[1]; 773 pps_tf[1] = pps_tf[0]; 774 pps_tf[0].tv_sec = u_sec; 775 pps_tf[0].tv_nsec = u_nsec; 776 777 /* 778 * Update the frequency accumulator using the difference between the 779 * current and previous PPS event measured directly by the timecounter. 780 */ 781 pps_fcount += delta_nsec - NANOSECOND; 782 if (v_nsec > MAXFREQ || v_nsec < -MAXFREQ) 783 goto out; 784 time_status &= ~STA_PPSJITTER; 785 786 /* 787 * A three-stage median filter is used to help denoise the PPS 788 * time. The median sample becomes the time offset estimate; the 789 * difference between the other two samples becomes the time 790 * dispersion (jitter) estimate. 791 */ 792 if (pps_tf[0].tv_nsec > pps_tf[1].tv_nsec) { 793 if (pps_tf[1].tv_nsec > pps_tf[2].tv_nsec) { 794 v_nsec = pps_tf[1].tv_nsec; /* 0 1 2 */ 795 u_nsec = pps_tf[0].tv_nsec - pps_tf[2].tv_nsec; 796 } else if (pps_tf[2].tv_nsec > pps_tf[0].tv_nsec) { 797 v_nsec = pps_tf[0].tv_nsec; /* 2 0 1 */ 798 u_nsec = pps_tf[2].tv_nsec - pps_tf[1].tv_nsec; 799 } else { 800 v_nsec = pps_tf[2].tv_nsec; /* 0 2 1 */ 801 u_nsec = pps_tf[0].tv_nsec - pps_tf[1].tv_nsec; 802 } 803 } else { 804 if (pps_tf[1].tv_nsec < pps_tf[2].tv_nsec) { 805 v_nsec = pps_tf[1].tv_nsec; /* 2 1 0 */ 806 u_nsec = pps_tf[2].tv_nsec - pps_tf[0].tv_nsec; 807 } else if (pps_tf[2].tv_nsec < pps_tf[0].tv_nsec) { 808 v_nsec = pps_tf[0].tv_nsec; /* 1 0 2 */ 809 u_nsec = pps_tf[1].tv_nsec - pps_tf[2].tv_nsec; 810 } else { 811 v_nsec = pps_tf[2].tv_nsec; /* 1 2 0 */ 812 u_nsec = pps_tf[1].tv_nsec - pps_tf[0].tv_nsec; 813 } 814 } 815 816 /* 817 * Nominal jitter is due to PPS signal noise and interrupt 818 * latency. If it exceeds the popcorn threshold, the sample is 819 * discarded. otherwise, if so enabled, the time offset is 820 * updated. We can tolerate a modest loss of data here without 821 * much degrading time accuracy. 822 * 823 * The measurements being checked here were made with the system 824 * timecounter, so the popcorn threshold is not allowed to fall below 825 * the number of nanoseconds in two ticks of the timecounter. For a 826 * timecounter running faster than 1 GHz the lower bound is 2ns, just 827 * to avoid a nonsensical threshold of zero. 828 */ 829 if (u_nsec > lmax(pps_jitter << PPS_POPCORN, 830 2 * (NANOSECOND / (long)qmin(NANOSECOND, tc_getfrequency())))) { 831 time_status |= STA_PPSJITTER; 832 pps_jitcnt++; 833 } else if (time_status & STA_PPSTIME) { 834 time_monitor = -v_nsec; 835 L_LINT(time_offset, time_monitor); 836 } 837 pps_jitter += (u_nsec - pps_jitter) >> PPS_FAVG; 838 u_sec = pps_tf[0].tv_sec - pps_lastsec; 839 if (u_sec < (1 << pps_shift)) 840 goto out; 841 842 /* 843 * At the end of the calibration interval the difference between 844 * the first and last counter values becomes the scaled 845 * frequency. It will later be divided by the length of the 846 * interval to determine the frequency update. If the frequency 847 * exceeds a sanity threshold, or if the actual calibration 848 * interval is not equal to the expected length, the data are 849 * discarded. We can tolerate a modest loss of data here without 850 * much degrading frequency accuracy. 851 */ 852 pps_calcnt++; 853 v_nsec = -pps_fcount; 854 pps_lastsec = pps_tf[0].tv_sec; 855 pps_fcount = 0; 856 u_nsec = MAXFREQ << pps_shift; 857 if (v_nsec > u_nsec || v_nsec < -u_nsec || u_sec != (1 << pps_shift)) { 858 time_status |= STA_PPSERROR; 859 pps_errcnt++; 860 goto out; 861 } 862 863 /* 864 * Here the raw frequency offset and wander (stability) is 865 * calculated. If the wander is less than the wander threshold 866 * for four consecutive averaging intervals, the interval is 867 * doubled; if it is greater than the threshold for four 868 * consecutive intervals, the interval is halved. The scaled 869 * frequency offset is converted to frequency offset. The 870 * stability metric is calculated as the average of recent 871 * frequency changes, but is used only for performance 872 * monitoring. 873 */ 874 L_LINT(ftemp, v_nsec); 875 L_RSHIFT(ftemp, pps_shift); 876 L_SUB(ftemp, pps_freq); 877 u_nsec = L_GINT(ftemp); 878 if (u_nsec > PPS_MAXWANDER) { 879 L_LINT(ftemp, PPS_MAXWANDER); 880 pps_intcnt--; 881 time_status |= STA_PPSWANDER; 882 pps_stbcnt++; 883 } else if (u_nsec < -PPS_MAXWANDER) { 884 L_LINT(ftemp, -PPS_MAXWANDER); 885 pps_intcnt--; 886 time_status |= STA_PPSWANDER; 887 pps_stbcnt++; 888 } else { 889 pps_intcnt++; 890 } 891 if (pps_intcnt >= 4) { 892 pps_intcnt = 4; 893 if (pps_shift < pps_shiftmax) { 894 pps_shift++; 895 pps_intcnt = 0; 896 } 897 } else if (pps_intcnt <= -4 || pps_shift > pps_shiftmax) { 898 pps_intcnt = -4; 899 if (pps_shift > PPS_FAVG) { 900 pps_shift--; 901 pps_intcnt = 0; 902 } 903 } 904 if (u_nsec < 0) 905 u_nsec = -u_nsec; 906 pps_stabil += (u_nsec * SCALE_PPM - pps_stabil) >> PPS_FAVG; 907 908 /* 909 * The PPS frequency is recalculated and clamped to the maximum 910 * MAXFREQ. If enabled, the system clock frequency is updated as 911 * well. 912 */ 913 L_ADD(pps_freq, ftemp); 914 u_nsec = L_GINT(pps_freq); 915 if (u_nsec > MAXFREQ) 916 L_LINT(pps_freq, MAXFREQ); 917 else if (u_nsec < -MAXFREQ) 918 L_LINT(pps_freq, -MAXFREQ); 919 if (time_status & STA_PPSFREQ) 920 time_freq = pps_freq; 921 922out: 923 NTP_UNLOCK(); 924} 925#endif /* PPS_SYNC */ 926 927#ifndef _SYS_SYSPROTO_H_ 928struct adjtime_args { 929 struct timeval *delta; 930 struct timeval *olddelta; 931}; 932#endif 933/* ARGSUSED */ 934int 935sys_adjtime(struct thread *td, struct adjtime_args *uap) 936{ 937 struct timeval delta, olddelta, *deltap; 938 int error; 939 940 if (uap->delta) { 941 error = copyin(uap->delta, &delta, sizeof(delta)); 942 if (error) 943 return (error); 944 deltap = δ 945 } else 946 deltap = NULL; 947 error = kern_adjtime(td, deltap, &olddelta); 948 if (uap->olddelta && error == 0) 949 error = copyout(&olddelta, uap->olddelta, sizeof(olddelta)); 950 return (error); 951} 952 953int 954kern_adjtime(struct thread *td, struct timeval *delta, struct timeval *olddelta) 955{ 956 struct timeval atv; 957 int64_t ltr, ltw; 958 int error; 959 960 if (delta != NULL) { 961 error = priv_check(td, PRIV_ADJTIME); 962 if (error != 0) 963 return (error); 964 ltw = (int64_t)delta->tv_sec * 1000000 + delta->tv_usec; 965 } 966 NTP_LOCK(); 967 ltr = time_adjtime; 968 if (delta != NULL) 969 time_adjtime = ltw; 970 NTP_UNLOCK(); 971 if (olddelta != NULL) { 972 atv.tv_sec = ltr / 1000000; 973 atv.tv_usec = ltr % 1000000; 974 if (atv.tv_usec < 0) { 975 atv.tv_usec += 1000000; 976 atv.tv_sec--; 977 } 978 *olddelta = atv; 979 } 980 return (0); 981} 982 983static struct callout resettodr_callout; 984static int resettodr_period = 1800; 985 986static void 987periodic_resettodr(void *arg __unused) 988{ 989 990 /* 991 * Read of time_status is lock-less, which is fine since 992 * ntp_is_time_error() operates on the consistent read value. 993 */ 994 if (!ntp_is_time_error(time_status)) 995 resettodr(); 996 if (resettodr_period > 0) 997 callout_schedule(&resettodr_callout, resettodr_period * hz); 998} 999 1000static void 1001shutdown_resettodr(void *arg __unused, int howto __unused) 1002{ 1003 1004 callout_drain(&resettodr_callout); 1005 /* Another unlocked read of time_status */ 1006 if (resettodr_period > 0 && !ntp_is_time_error(time_status)) 1007 resettodr(); 1008} 1009 1010static int 1011sysctl_resettodr_period(SYSCTL_HANDLER_ARGS) 1012{ 1013 int error; 1014 1015 error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req); 1016 if (error || !req->newptr) 1017 return (error); 1018 if (cold) 1019 goto done; 1020 if (resettodr_period == 0) 1021 callout_stop(&resettodr_callout); 1022 else 1023 callout_reset(&resettodr_callout, resettodr_period * hz, 1024 periodic_resettodr, NULL); 1025done: 1026 return (0); 1027} 1028 1029SYSCTL_PROC(_machdep, OID_AUTO, rtc_save_period, CTLTYPE_INT | CTLFLAG_RWTUN | 1030 CTLFLAG_MPSAFE, &resettodr_period, 1800, sysctl_resettodr_period, "I", 1031 "Save system time to RTC with this period (in seconds)"); 1032 1033static void 1034start_periodic_resettodr(void *arg __unused) 1035{ 1036 1037 EVENTHANDLER_REGISTER(shutdown_pre_sync, shutdown_resettodr, NULL, 1038 SHUTDOWN_PRI_FIRST); 1039 callout_init(&resettodr_callout, 1); 1040 if (resettodr_period == 0) 1041 return; 1042 callout_reset(&resettodr_callout, resettodr_period * hz, 1043 periodic_resettodr, NULL); 1044} 1045 1046SYSINIT(periodic_resettodr, SI_SUB_LAST, SI_ORDER_MIDDLE, 1047 start_periodic_resettodr, NULL); 1048