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 __FBSDID("$FreeBSD$"); 35 36 #include "opt_ntp.h" 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/sysproto.h> 41 #include <sys/eventhandler.h> 42 #include <sys/kernel.h> 43 #include <sys/priv.h> 44 #include <sys/proc.h> 45 #include <sys/lock.h> 46 #include <sys/mutex.h> 47 #include <sys/time.h> 48 #include <sys/timex.h> 49 #include <sys/timetc.h> 50 #include <sys/timepps.h> 51 #include <sys/syscallsubr.h> 52 #include <sys/sysctl.h> 53 54 /* 55 * Single-precision macros for 64-bit machines 56 */ 57 typedef int64_t l_fp; 58 #define L_ADD(v, u) ((v) += (u)) 59 #define L_SUB(v, u) ((v) -= (u)) 60 #define L_ADDHI(v, a) ((v) += (int64_t)(a) << 32) 61 #define L_NEG(v) ((v) = -(v)) 62 #define L_RSHIFT(v, n) \ 63 do { \ 64 if ((v) < 0) \ 65 (v) = -(-(v) >> (n)); \ 66 else \ 67 (v) = (v) >> (n); \ 68 } while (0) 69 #define L_MPY(v, a) ((v) *= (a)) 70 #define L_CLR(v) ((v) = 0) 71 #define L_ISNEG(v) ((v) < 0) 72 #define L_LINT(v, a) ((v) = (int64_t)(a) << 32) 73 #define L_GINT(v) ((v) < 0 ? -(-(v) >> 32) : (v) >> 32) 74 75 /* 76 * Generic NTP kernel interface 77 * 78 * These routines constitute the Network Time Protocol (NTP) interfaces 79 * for user and daemon application programs. The ntp_gettime() routine 80 * provides the time, maximum error (synch distance) and estimated error 81 * (dispersion) to client user application programs. The ntp_adjtime() 82 * routine is used by the NTP daemon to adjust the system clock to an 83 * externally derived time. The time offset and related variables set by 84 * this routine are used by other routines in this module to adjust the 85 * phase and frequency of the clock discipline loop which controls the 86 * system clock. 87 * 88 * When the kernel time is reckoned directly in nanoseconds (NTP_NANO 89 * defined), the time at each tick interrupt is derived directly from 90 * the kernel time variable. When the kernel time is reckoned in 91 * microseconds, (NTP_NANO undefined), the time is derived from the 92 * kernel time variable together with a variable representing the 93 * leftover nanoseconds at the last tick interrupt. In either case, the 94 * current nanosecond time is reckoned from these values plus an 95 * interpolated value derived by the clock routines in another 96 * architecture-specific module. The interpolation can use either a 97 * dedicated counter or a processor cycle counter (PCC) implemented in 98 * some architectures. 99 * 100 * Note that all routines must run at priority splclock or higher. 101 */ 102 /* 103 * Phase/frequency-lock loop (PLL/FLL) definitions 104 * 105 * The nanosecond clock discipline uses two variable types, time 106 * variables and frequency variables. Both types are represented as 64- 107 * bit fixed-point quantities with the decimal point between two 32-bit 108 * halves. On a 32-bit machine, each half is represented as a single 109 * word and mathematical operations are done using multiple-precision 110 * arithmetic. On a 64-bit machine, ordinary computer arithmetic is 111 * used. 112 * 113 * A time variable is a signed 64-bit fixed-point number in ns and 114 * fraction. It represents the remaining time offset to be amortized 115 * over succeeding tick interrupts. The maximum time offset is about 116 * 0.5 s and the resolution is about 2.3e-10 ns. 117 * 118 * 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 119 * 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 1 120 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 121 * |s s s| ns | 122 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 123 * | fraction | 124 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 125 * 126 * A frequency variable is a signed 64-bit fixed-point number in ns/s 127 * and fraction. It represents the ns and fraction to be added to the 128 * kernel time variable at each second. The maximum frequency offset is 129 * about +-500000 ns/s and the resolution is about 2.3e-10 ns/s. 130 * 131 * 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 132 * 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 1 133 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 134 * |s s s s s s s s s s s s s| ns/s | 135 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 136 * | fraction | 137 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 138 */ 139 /* 140 * The following variables establish the state of the PLL/FLL and the 141 * residual time and frequency offset of the local clock. 142 */ 143 #define SHIFT_PLL 4 /* PLL loop gain (shift) */ 144 #define SHIFT_FLL 2 /* FLL loop gain (shift) */ 145 146 static int time_state = TIME_OK; /* clock state */ 147 static int time_status = STA_UNSYNC; /* clock status bits */ 148 static long time_tai; /* TAI offset (s) */ 149 static long time_monitor; /* last time offset scaled (ns) */ 150 static long time_constant; /* poll interval (shift) (s) */ 151 static long time_precision = 1; /* clock precision (ns) */ 152 static long time_maxerror = MAXPHASE / 1000; /* maximum error (us) */ 153 static long time_esterror = MAXPHASE / 1000; /* estimated error (us) */ 154 static long time_reftime; /* time at last adjustment (s) */ 155 static l_fp time_offset; /* time offset (ns) */ 156 static l_fp time_freq; /* frequency offset (ns/s) */ 157 static l_fp time_adj; /* tick adjust (ns/s) */ 158 159 static int64_t time_adjtime; /* correction from adjtime(2) (usec) */ 160 161 #ifdef PPS_SYNC 162 /* 163 * The following variables are used when a pulse-per-second (PPS) signal 164 * is available and connected via a modem control lead. They establish 165 * the engineering parameters of the clock discipline loop when 166 * controlled by the PPS signal. 167 */ 168 #define PPS_FAVG 2 /* min freq avg interval (s) (shift) */ 169 #define PPS_FAVGDEF 8 /* default freq avg int (s) (shift) */ 170 #define PPS_FAVGMAX 15 /* max freq avg interval (s) (shift) */ 171 #define PPS_PAVG 4 /* phase avg interval (s) (shift) */ 172 #define PPS_VALID 120 /* PPS signal watchdog max (s) */ 173 #define PPS_MAXWANDER 100000 /* max PPS wander (ns/s) */ 174 #define PPS_POPCORN 2 /* popcorn spike threshold (shift) */ 175 176 static struct timespec pps_tf[3]; /* phase median filter */ 177 static l_fp pps_freq; /* scaled frequency offset (ns/s) */ 178 static long pps_fcount; /* frequency accumulator */ 179 static long pps_jitter; /* nominal jitter (ns) */ 180 static long pps_stabil; /* nominal stability (scaled ns/s) */ 181 static long pps_lastsec; /* time at last calibration (s) */ 182 static int pps_valid; /* signal watchdog counter */ 183 static int pps_shift = PPS_FAVG; /* interval duration (s) (shift) */ 184 static int pps_shiftmax = PPS_FAVGDEF; /* max interval duration (s) (shift) */ 185 static int pps_intcnt; /* wander counter */ 186 187 /* 188 * PPS signal quality monitors 189 */ 190 static long pps_calcnt; /* calibration intervals */ 191 static long pps_jitcnt; /* jitter limit exceeded */ 192 static long pps_stbcnt; /* stability limit exceeded */ 193 static long pps_errcnt; /* calibration errors */ 194 #endif /* PPS_SYNC */ 195 /* 196 * End of phase/frequency-lock loop (PLL/FLL) definitions 197 */ 198 199 static void ntp_init(void); 200 static void hardupdate(long offset); 201 static void ntp_gettime1(struct ntptimeval *ntvp); 202 static int ntp_is_time_error(void); 203 204 static int 205 ntp_is_time_error(void) 206 { 207 /* 208 * Status word error decode. If any of these conditions occur, 209 * an error is returned, instead of the status word. Most 210 * applications will care only about the fact the system clock 211 * may not be trusted, not about the details. 212 * 213 * Hardware or software error 214 */ 215 if ((time_status & (STA_UNSYNC | STA_CLOCKERR)) || 216 217 /* 218 * PPS signal lost when either time or frequency synchronization 219 * requested 220 */ 221 (time_status & (STA_PPSFREQ | STA_PPSTIME) && 222 !(time_status & STA_PPSSIGNAL)) || 223 224 /* 225 * PPS jitter exceeded when time synchronization requested 226 */ 227 (time_status & STA_PPSTIME && 228 time_status & STA_PPSJITTER) || 229 230 /* 231 * PPS wander exceeded or calibration error when frequency 232 * synchronization requested 233 */ 234 (time_status & STA_PPSFREQ && 235 time_status & (STA_PPSWANDER | STA_PPSERROR))) 236 return (1); 237 238 return (0); 239 } 240 241 static void 242 ntp_gettime1(struct ntptimeval *ntvp) 243 { 244 struct timespec atv; /* nanosecond time */ 245 246 GIANT_REQUIRED; 247 248 nanotime(&atv); 249 ntvp->time.tv_sec = atv.tv_sec; 250 ntvp->time.tv_nsec = atv.tv_nsec; 251 ntvp->maxerror = time_maxerror; 252 ntvp->esterror = time_esterror; 253 ntvp->tai = time_tai; 254 ntvp->time_state = time_state; 255 256 if (ntp_is_time_error()) 257 ntvp->time_state = TIME_ERROR; 258 } 259 260 /* 261 * ntp_gettime() - NTP user application interface 262 * 263 * See the timex.h header file for synopsis and API description. Note that 264 * the TAI offset is returned in the ntvtimeval.tai structure member. 265 */ 266 #ifndef _SYS_SYSPROTO_H_ 267 struct ntp_gettime_args { 268 struct ntptimeval *ntvp; 269 }; 270 #endif 271 /* ARGSUSED */ 272 int 273 ntp_gettime(struct thread *td, struct ntp_gettime_args *uap) 274 { 275 struct ntptimeval ntv; 276 277 mtx_lock(&Giant); 278 ntp_gettime1(&ntv); 279 mtx_unlock(&Giant); 280 281 td->td_retval[0] = ntv.time_state; 282 return (copyout(&ntv, uap->ntvp, sizeof(ntv))); 283 } 284 285 static int 286 ntp_sysctl(SYSCTL_HANDLER_ARGS) 287 { 288 struct ntptimeval ntv; /* temporary structure */ 289 290 ntp_gettime1(&ntv); 291 292 return (sysctl_handle_opaque(oidp, &ntv, sizeof(ntv), req)); 293 } 294 295 SYSCTL_NODE(_kern, OID_AUTO, ntp_pll, CTLFLAG_RW, 0, ""); 296 SYSCTL_PROC(_kern_ntp_pll, OID_AUTO, gettime, CTLTYPE_OPAQUE|CTLFLAG_RD, 297 0, sizeof(struct ntptimeval) , ntp_sysctl, "S,ntptimeval", ""); 298 299 #ifdef PPS_SYNC 300 SYSCTL_INT(_kern_ntp_pll, OID_AUTO, pps_shiftmax, CTLFLAG_RW, &pps_shiftmax, 0, ""); 301 SYSCTL_INT(_kern_ntp_pll, OID_AUTO, pps_shift, CTLFLAG_RW, &pps_shift, 0, ""); 302 SYSCTL_INT(_kern_ntp_pll, OID_AUTO, time_monitor, CTLFLAG_RD, &time_monitor, 0, ""); 303 304 SYSCTL_OPAQUE(_kern_ntp_pll, OID_AUTO, pps_freq, CTLFLAG_RD, &pps_freq, sizeof(pps_freq), "I", ""); 305 SYSCTL_OPAQUE(_kern_ntp_pll, OID_AUTO, time_freq, CTLFLAG_RD, &time_freq, sizeof(time_freq), "I", ""); 306 #endif 307 308 /* 309 * ntp_adjtime() - NTP daemon application interface 310 * 311 * See the timex.h header file for synopsis and API description. Note that 312 * the timex.constant structure member has a dual purpose to set the time 313 * constant and to set the TAI offset. 314 */ 315 #ifndef _SYS_SYSPROTO_H_ 316 struct ntp_adjtime_args { 317 struct timex *tp; 318 }; 319 #endif 320 321 int 322 ntp_adjtime(struct thread *td, struct ntp_adjtime_args *uap) 323 { 324 struct timex ntv; /* temporary structure */ 325 long freq; /* frequency ns/s) */ 326 int modes; /* mode bits from structure */ 327 int s; /* caller priority */ 328 int error; 329 330 error = copyin((caddr_t)uap->tp, (caddr_t)&ntv, sizeof(ntv)); 331 if (error) 332 return(error); 333 334 /* 335 * Update selected clock variables - only the superuser can 336 * change anything. Note that there is no error checking here on 337 * the assumption the superuser should know what it is doing. 338 * Note that either the time constant or TAI offset are loaded 339 * from the ntv.constant member, depending on the mode bits. If 340 * the STA_PLL bit in the status word is cleared, the state and 341 * status words are reset to the initial values at boot. 342 */ 343 mtx_lock(&Giant); 344 modes = ntv.modes; 345 if (modes) 346 error = priv_check(td, PRIV_NTP_ADJTIME); 347 if (error) 348 goto done2; 349 s = splclock(); 350 if (modes & MOD_MAXERROR) 351 time_maxerror = ntv.maxerror; 352 if (modes & MOD_ESTERROR) 353 time_esterror = ntv.esterror; 354 if (modes & MOD_STATUS) { 355 if (time_status & STA_PLL && !(ntv.status & STA_PLL)) { 356 time_state = TIME_OK; 357 time_status = STA_UNSYNC; 358 #ifdef PPS_SYNC 359 pps_shift = PPS_FAVG; 360 #endif /* PPS_SYNC */ 361 } 362 time_status &= STA_RONLY; 363 time_status |= ntv.status & ~STA_RONLY; 364 } 365 if (modes & MOD_TIMECONST) { 366 if (ntv.constant < 0) 367 time_constant = 0; 368 else if (ntv.constant > MAXTC) 369 time_constant = MAXTC; 370 else 371 time_constant = ntv.constant; 372 } 373 if (modes & MOD_TAI) { 374 if (ntv.constant > 0) /* XXX zero & negative numbers ? */ 375 time_tai = ntv.constant; 376 } 377 #ifdef PPS_SYNC 378 if (modes & MOD_PPSMAX) { 379 if (ntv.shift < PPS_FAVG) 380 pps_shiftmax = PPS_FAVG; 381 else if (ntv.shift > PPS_FAVGMAX) 382 pps_shiftmax = PPS_FAVGMAX; 383 else 384 pps_shiftmax = ntv.shift; 385 } 386 #endif /* PPS_SYNC */ 387 if (modes & MOD_NANO) 388 time_status |= STA_NANO; 389 if (modes & MOD_MICRO) 390 time_status &= ~STA_NANO; 391 if (modes & MOD_CLKB) 392 time_status |= STA_CLK; 393 if (modes & MOD_CLKA) 394 time_status &= ~STA_CLK; 395 if (modes & MOD_FREQUENCY) { 396 freq = (ntv.freq * 1000LL) >> 16; 397 if (freq > MAXFREQ) 398 L_LINT(time_freq, MAXFREQ); 399 else if (freq < -MAXFREQ) 400 L_LINT(time_freq, -MAXFREQ); 401 else { 402 /* 403 * ntv.freq is [PPM * 2^16] = [us/s * 2^16] 404 * time_freq is [ns/s * 2^32] 405 */ 406 time_freq = ntv.freq * 1000LL * 65536LL; 407 } 408 #ifdef PPS_SYNC 409 pps_freq = time_freq; 410 #endif /* PPS_SYNC */ 411 } 412 if (modes & MOD_OFFSET) { 413 if (time_status & STA_NANO) 414 hardupdate(ntv.offset); 415 else 416 hardupdate(ntv.offset * 1000); 417 } 418 419 /* 420 * Retrieve all clock variables. Note that the TAI offset is 421 * returned only by ntp_gettime(); 422 */ 423 if (time_status & STA_NANO) 424 ntv.offset = L_GINT(time_offset); 425 else 426 ntv.offset = L_GINT(time_offset) / 1000; /* XXX rounding ? */ 427 ntv.freq = L_GINT((time_freq / 1000LL) << 16); 428 ntv.maxerror = time_maxerror; 429 ntv.esterror = time_esterror; 430 ntv.status = time_status; 431 ntv.constant = time_constant; 432 if (time_status & STA_NANO) 433 ntv.precision = time_precision; 434 else 435 ntv.precision = time_precision / 1000; 436 ntv.tolerance = MAXFREQ * SCALE_PPM; 437 #ifdef PPS_SYNC 438 ntv.shift = pps_shift; 439 ntv.ppsfreq = L_GINT((pps_freq / 1000LL) << 16); 440 if (time_status & STA_NANO) 441 ntv.jitter = pps_jitter; 442 else 443 ntv.jitter = pps_jitter / 1000; 444 ntv.stabil = pps_stabil; 445 ntv.calcnt = pps_calcnt; 446 ntv.errcnt = pps_errcnt; 447 ntv.jitcnt = pps_jitcnt; 448 ntv.stbcnt = pps_stbcnt; 449 #endif /* PPS_SYNC */ 450 splx(s); 451 452 error = copyout((caddr_t)&ntv, (caddr_t)uap->tp, sizeof(ntv)); 453 if (error) 454 goto done2; 455 456 if (ntp_is_time_error()) 457 td->td_retval[0] = TIME_ERROR; 458 else 459 td->td_retval[0] = time_state; 460 461 done2: 462 mtx_unlock(&Giant); 463 return (error); 464 } 465 466 /* 467 * second_overflow() - called after ntp_tick_adjust() 468 * 469 * This routine is ordinarily called immediately following the above 470 * routine ntp_tick_adjust(). While these two routines are normally 471 * combined, they are separated here only for the purposes of 472 * simulation. 473 */ 474 void 475 ntp_update_second(int64_t *adjustment, time_t *newsec) 476 { 477 int tickrate; 478 l_fp ftemp; /* 32/64-bit temporary */ 479 480 /* 481 * On rollover of the second both the nanosecond and microsecond 482 * clocks are updated and the state machine cranked as 483 * necessary. The phase adjustment to be used for the next 484 * second is calculated and the maximum error is increased by 485 * the tolerance. 486 */ 487 time_maxerror += MAXFREQ / 1000; 488 489 /* 490 * Leap second processing. If in leap-insert state at 491 * the end of the day, the system clock is set back one 492 * second; if in leap-delete state, the system clock is 493 * set ahead one second. The nano_time() routine or 494 * external clock driver will insure that reported time 495 * is always monotonic. 496 */ 497 switch (time_state) { 498 499 /* 500 * No warning. 501 */ 502 case TIME_OK: 503 if (time_status & STA_INS) 504 time_state = TIME_INS; 505 else if (time_status & STA_DEL) 506 time_state = TIME_DEL; 507 break; 508 509 /* 510 * Insert second 23:59:60 following second 511 * 23:59:59. 512 */ 513 case TIME_INS: 514 if (!(time_status & STA_INS)) 515 time_state = TIME_OK; 516 else if ((*newsec) % 86400 == 0) { 517 (*newsec)--; 518 time_state = TIME_OOP; 519 time_tai++; 520 } 521 break; 522 523 /* 524 * Delete second 23:59:59. 525 */ 526 case TIME_DEL: 527 if (!(time_status & STA_DEL)) 528 time_state = TIME_OK; 529 else if (((*newsec) + 1) % 86400 == 0) { 530 (*newsec)++; 531 time_tai--; 532 time_state = TIME_WAIT; 533 } 534 break; 535 536 /* 537 * Insert second in progress. 538 */ 539 case TIME_OOP: 540 time_state = TIME_WAIT; 541 break; 542 543 /* 544 * Wait for status bits to clear. 545 */ 546 case TIME_WAIT: 547 if (!(time_status & (STA_INS | STA_DEL))) 548 time_state = TIME_OK; 549 } 550 551 /* 552 * Compute the total time adjustment for the next second 553 * in ns. The offset is reduced by a factor depending on 554 * whether the PPS signal is operating. Note that the 555 * value is in effect scaled by the clock frequency, 556 * since the adjustment is added at each tick interrupt. 557 */ 558 ftemp = time_offset; 559 #ifdef PPS_SYNC 560 /* XXX even if PPS signal dies we should finish adjustment ? */ 561 if (time_status & STA_PPSTIME && time_status & 562 STA_PPSSIGNAL) 563 L_RSHIFT(ftemp, pps_shift); 564 else 565 L_RSHIFT(ftemp, SHIFT_PLL + time_constant); 566 #else 567 L_RSHIFT(ftemp, SHIFT_PLL + time_constant); 568 #endif /* PPS_SYNC */ 569 time_adj = ftemp; 570 L_SUB(time_offset, ftemp); 571 L_ADD(time_adj, time_freq); 572 573 /* 574 * Apply any correction from adjtime(2). If more than one second 575 * off we slew at a rate of 5ms/s (5000 PPM) else 500us/s (500PPM) 576 * until the last second is slewed the final < 500 usecs. 577 */ 578 if (time_adjtime != 0) { 579 if (time_adjtime > 1000000) 580 tickrate = 5000; 581 else if (time_adjtime < -1000000) 582 tickrate = -5000; 583 else if (time_adjtime > 500) 584 tickrate = 500; 585 else if (time_adjtime < -500) 586 tickrate = -500; 587 else 588 tickrate = time_adjtime; 589 time_adjtime -= tickrate; 590 L_LINT(ftemp, tickrate * 1000); 591 L_ADD(time_adj, ftemp); 592 } 593 *adjustment = time_adj; 594 595 #ifdef PPS_SYNC 596 if (pps_valid > 0) 597 pps_valid--; 598 else 599 time_status &= ~STA_PPSSIGNAL; 600 #endif /* PPS_SYNC */ 601 } 602 603 /* 604 * ntp_init() - initialize variables and structures 605 * 606 * This routine must be called after the kernel variables hz and tick 607 * are set or changed and before the next tick interrupt. In this 608 * particular implementation, these values are assumed set elsewhere in 609 * the kernel. The design allows the clock frequency and tick interval 610 * to be changed while the system is running. So, this routine should 611 * probably be integrated with the code that does that. 612 */ 613 static void 614 ntp_init() 615 { 616 617 /* 618 * The following variables are initialized only at startup. Only 619 * those structures not cleared by the compiler need to be 620 * initialized, and these only in the simulator. In the actual 621 * kernel, any nonzero values here will quickly evaporate. 622 */ 623 L_CLR(time_offset); 624 L_CLR(time_freq); 625 #ifdef PPS_SYNC 626 pps_tf[0].tv_sec = pps_tf[0].tv_nsec = 0; 627 pps_tf[1].tv_sec = pps_tf[1].tv_nsec = 0; 628 pps_tf[2].tv_sec = pps_tf[2].tv_nsec = 0; 629 pps_fcount = 0; 630 L_CLR(pps_freq); 631 #endif /* PPS_SYNC */ 632 } 633 634 SYSINIT(ntpclocks, SI_SUB_CLOCKS, SI_ORDER_MIDDLE, ntp_init, NULL); 635 636 /* 637 * hardupdate() - local clock update 638 * 639 * This routine is called by ntp_adjtime() to update the local clock 640 * phase and frequency. The implementation is of an adaptive-parameter, 641 * hybrid phase/frequency-lock loop (PLL/FLL). The routine computes new 642 * time and frequency offset estimates for each call. If the kernel PPS 643 * discipline code is configured (PPS_SYNC), the PPS signal itself 644 * determines the new time offset, instead of the calling argument. 645 * Presumably, calls to ntp_adjtime() occur only when the caller 646 * believes the local clock is valid within some bound (+-128 ms with 647 * NTP). If the caller's time is far different than the PPS time, an 648 * argument will ensue, and it's not clear who will lose. 649 * 650 * For uncompensated quartz crystal oscillators and nominal update 651 * intervals less than 256 s, operation should be in phase-lock mode, 652 * where the loop is disciplined to phase. For update intervals greater 653 * than 1024 s, operation should be in frequency-lock mode, where the 654 * loop is disciplined to frequency. Between 256 s and 1024 s, the mode 655 * is selected by the STA_MODE status bit. 656 */ 657 static void 658 hardupdate(offset) 659 long offset; /* clock offset (ns) */ 660 { 661 long mtemp; 662 l_fp ftemp; 663 664 /* 665 * Select how the phase is to be controlled and from which 666 * source. If the PPS signal is present and enabled to 667 * discipline the time, the PPS offset is used; otherwise, the 668 * argument offset is used. 669 */ 670 if (!(time_status & STA_PLL)) 671 return; 672 if (!(time_status & STA_PPSTIME && time_status & 673 STA_PPSSIGNAL)) { 674 if (offset > MAXPHASE) 675 time_monitor = MAXPHASE; 676 else if (offset < -MAXPHASE) 677 time_monitor = -MAXPHASE; 678 else 679 time_monitor = offset; 680 L_LINT(time_offset, time_monitor); 681 } 682 683 /* 684 * Select how the frequency is to be controlled and in which 685 * mode (PLL or FLL). If the PPS signal is present and enabled 686 * to discipline the frequency, the PPS frequency is used; 687 * otherwise, the argument offset is used to compute it. 688 */ 689 if (time_status & STA_PPSFREQ && time_status & STA_PPSSIGNAL) { 690 time_reftime = time_second; 691 return; 692 } 693 if (time_status & STA_FREQHOLD || time_reftime == 0) 694 time_reftime = time_second; 695 mtemp = time_second - time_reftime; 696 L_LINT(ftemp, time_monitor); 697 L_RSHIFT(ftemp, (SHIFT_PLL + 2 + time_constant) << 1); 698 L_MPY(ftemp, mtemp); 699 L_ADD(time_freq, ftemp); 700 time_status &= ~STA_MODE; 701 if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > 702 MAXSEC)) { 703 L_LINT(ftemp, (time_monitor << 4) / mtemp); 704 L_RSHIFT(ftemp, SHIFT_FLL + 4); 705 L_ADD(time_freq, ftemp); 706 time_status |= STA_MODE; 707 } 708 time_reftime = time_second; 709 if (L_GINT(time_freq) > MAXFREQ) 710 L_LINT(time_freq, MAXFREQ); 711 else if (L_GINT(time_freq) < -MAXFREQ) 712 L_LINT(time_freq, -MAXFREQ); 713 } 714 715 #ifdef PPS_SYNC 716 /* 717 * hardpps() - discipline CPU clock oscillator to external PPS signal 718 * 719 * This routine is called at each PPS interrupt in order to discipline 720 * the CPU clock oscillator to the PPS signal. There are two independent 721 * first-order feedback loops, one for the phase, the other for the 722 * frequency. The phase loop measures and grooms the PPS phase offset 723 * and leaves it in a handy spot for the seconds overflow routine. The 724 * frequency loop averages successive PPS phase differences and 725 * calculates the PPS frequency offset, which is also processed by the 726 * seconds overflow routine. The code requires the caller to capture the 727 * time and architecture-dependent hardware counter values in 728 * nanoseconds at the on-time PPS signal transition. 729 * 730 * Note that, on some Unix systems this routine runs at an interrupt 731 * priority level higher than the timer interrupt routine hardclock(). 732 * Therefore, the variables used are distinct from the hardclock() 733 * variables, except for the actual time and frequency variables, which 734 * are determined by this routine and updated atomically. 735 */ 736 void 737 hardpps(tsp, nsec) 738 struct timespec *tsp; /* time at PPS */ 739 long nsec; /* hardware counter at PPS */ 740 { 741 long u_sec, u_nsec, v_nsec; /* temps */ 742 l_fp ftemp; 743 744 /* 745 * The signal is first processed by a range gate and frequency 746 * discriminator. The range gate rejects noise spikes outside 747 * the range +-500 us. The frequency discriminator rejects input 748 * signals with apparent frequency outside the range 1 +-500 749 * PPM. If two hits occur in the same second, we ignore the 750 * later hit; if not and a hit occurs outside the range gate, 751 * keep the later hit for later comparison, but do not process 752 * it. 753 */ 754 time_status |= STA_PPSSIGNAL | STA_PPSJITTER; 755 time_status &= ~(STA_PPSWANDER | STA_PPSERROR); 756 pps_valid = PPS_VALID; 757 u_sec = tsp->tv_sec; 758 u_nsec = tsp->tv_nsec; 759 if (u_nsec >= (NANOSECOND >> 1)) { 760 u_nsec -= NANOSECOND; 761 u_sec++; 762 } 763 v_nsec = u_nsec - pps_tf[0].tv_nsec; 764 if (u_sec == pps_tf[0].tv_sec && v_nsec < NANOSECOND - 765 MAXFREQ) 766 return; 767 pps_tf[2] = pps_tf[1]; 768 pps_tf[1] = pps_tf[0]; 769 pps_tf[0].tv_sec = u_sec; 770 pps_tf[0].tv_nsec = u_nsec; 771 772 /* 773 * Compute the difference between the current and previous 774 * counter values. If the difference exceeds 0.5 s, assume it 775 * has wrapped around, so correct 1.0 s. If the result exceeds 776 * the tick interval, the sample point has crossed a tick 777 * boundary during the last second, so correct the tick. Very 778 * intricate. 779 */ 780 u_nsec = nsec; 781 if (u_nsec > (NANOSECOND >> 1)) 782 u_nsec -= NANOSECOND; 783 else if (u_nsec < -(NANOSECOND >> 1)) 784 u_nsec += NANOSECOND; 785 pps_fcount += u_nsec; 786 if (v_nsec > MAXFREQ || v_nsec < -MAXFREQ) 787 return; 788 time_status &= ~STA_PPSJITTER; 789 790 /* 791 * A three-stage median filter is used to help denoise the PPS 792 * time. The median sample becomes the time offset estimate; the 793 * difference between the other two samples becomes the time 794 * dispersion (jitter) estimate. 795 */ 796 if (pps_tf[0].tv_nsec > pps_tf[1].tv_nsec) { 797 if (pps_tf[1].tv_nsec > pps_tf[2].tv_nsec) { 798 v_nsec = pps_tf[1].tv_nsec; /* 0 1 2 */ 799 u_nsec = pps_tf[0].tv_nsec - pps_tf[2].tv_nsec; 800 } else if (pps_tf[2].tv_nsec > pps_tf[0].tv_nsec) { 801 v_nsec = pps_tf[0].tv_nsec; /* 2 0 1 */ 802 u_nsec = pps_tf[2].tv_nsec - pps_tf[1].tv_nsec; 803 } else { 804 v_nsec = pps_tf[2].tv_nsec; /* 0 2 1 */ 805 u_nsec = pps_tf[0].tv_nsec - pps_tf[1].tv_nsec; 806 } 807 } else { 808 if (pps_tf[1].tv_nsec < pps_tf[2].tv_nsec) { 809 v_nsec = pps_tf[1].tv_nsec; /* 2 1 0 */ 810 u_nsec = pps_tf[2].tv_nsec - pps_tf[0].tv_nsec; 811 } else if (pps_tf[2].tv_nsec < pps_tf[0].tv_nsec) { 812 v_nsec = pps_tf[0].tv_nsec; /* 1 0 2 */ 813 u_nsec = pps_tf[1].tv_nsec - pps_tf[2].tv_nsec; 814 } else { 815 v_nsec = pps_tf[2].tv_nsec; /* 1 2 0 */ 816 u_nsec = pps_tf[1].tv_nsec - pps_tf[0].tv_nsec; 817 } 818 } 819 820 /* 821 * Nominal jitter is due to PPS signal noise and interrupt 822 * latency. If it exceeds the popcorn threshold, the sample is 823 * discarded. otherwise, if so enabled, the time offset is 824 * updated. We can tolerate a modest loss of data here without 825 * much degrading time accuracy. 826 */ 827 if (u_nsec > (pps_jitter << PPS_POPCORN)) { 828 time_status |= STA_PPSJITTER; 829 pps_jitcnt++; 830 } else if (time_status & STA_PPSTIME) { 831 time_monitor = -v_nsec; 832 L_LINT(time_offset, time_monitor); 833 } 834 pps_jitter += (u_nsec - pps_jitter) >> PPS_FAVG; 835 u_sec = pps_tf[0].tv_sec - pps_lastsec; 836 if (u_sec < (1 << pps_shift)) 837 return; 838 839 /* 840 * At the end of the calibration interval the difference between 841 * the first and last counter values becomes the scaled 842 * frequency. It will later be divided by the length of the 843 * interval to determine the frequency update. If the frequency 844 * exceeds a sanity threshold, or if the actual calibration 845 * interval is not equal to the expected length, the data are 846 * discarded. We can tolerate a modest loss of data here without 847 * much degrading frequency accuracy. 848 */ 849 pps_calcnt++; 850 v_nsec = -pps_fcount; 851 pps_lastsec = pps_tf[0].tv_sec; 852 pps_fcount = 0; 853 u_nsec = MAXFREQ << pps_shift; 854 if (v_nsec > u_nsec || v_nsec < -u_nsec || u_sec != (1 << 855 pps_shift)) { 856 time_status |= STA_PPSERROR; 857 pps_errcnt++; 858 return; 859 } 860 861 /* 862 * Here the raw frequency offset and wander (stability) is 863 * calculated. If the wander is less than the wander threshold 864 * for four consecutive averaging intervals, the interval is 865 * doubled; if it is greater than the threshold for four 866 * consecutive intervals, the interval is halved. The scaled 867 * frequency offset is converted to frequency offset. The 868 * stability metric is calculated as the average of recent 869 * frequency changes, but is used only for performance 870 * monitoring. 871 */ 872 L_LINT(ftemp, v_nsec); 873 L_RSHIFT(ftemp, pps_shift); 874 L_SUB(ftemp, pps_freq); 875 u_nsec = L_GINT(ftemp); 876 if (u_nsec > PPS_MAXWANDER) { 877 L_LINT(ftemp, PPS_MAXWANDER); 878 pps_intcnt--; 879 time_status |= STA_PPSWANDER; 880 pps_stbcnt++; 881 } else if (u_nsec < -PPS_MAXWANDER) { 882 L_LINT(ftemp, -PPS_MAXWANDER); 883 pps_intcnt--; 884 time_status |= STA_PPSWANDER; 885 pps_stbcnt++; 886 } else { 887 pps_intcnt++; 888 } 889 if (pps_intcnt >= 4) { 890 pps_intcnt = 4; 891 if (pps_shift < pps_shiftmax) { 892 pps_shift++; 893 pps_intcnt = 0; 894 } 895 } else if (pps_intcnt <= -4 || pps_shift > pps_shiftmax) { 896 pps_intcnt = -4; 897 if (pps_shift > PPS_FAVG) { 898 pps_shift--; 899 pps_intcnt = 0; 900 } 901 } 902 if (u_nsec < 0) 903 u_nsec = -u_nsec; 904 pps_stabil += (u_nsec * SCALE_PPM - pps_stabil) >> PPS_FAVG; 905 906 /* 907 * The PPS frequency is recalculated and clamped to the maximum 908 * MAXFREQ. If enabled, the system clock frequency is updated as 909 * well. 910 */ 911 L_ADD(pps_freq, ftemp); 912 u_nsec = L_GINT(pps_freq); 913 if (u_nsec > MAXFREQ) 914 L_LINT(pps_freq, MAXFREQ); 915 else if (u_nsec < -MAXFREQ) 916 L_LINT(pps_freq, -MAXFREQ); 917 if (time_status & STA_PPSFREQ) 918 time_freq = pps_freq; 919 } 920 #endif /* PPS_SYNC */ 921 922 #ifndef _SYS_SYSPROTO_H_ 923 struct adjtime_args { 924 struct timeval *delta; 925 struct timeval *olddelta; 926 }; 927 #endif 928 /* ARGSUSED */ 929 int 930 adjtime(struct thread *td, struct adjtime_args *uap) 931 { 932 struct timeval delta, olddelta, *deltap; 933 int error; 934 935 if (uap->delta) { 936 error = copyin(uap->delta, &delta, sizeof(delta)); 937 if (error) 938 return (error); 939 deltap = δ 940 } else 941 deltap = NULL; 942 error = kern_adjtime(td, deltap, &olddelta); 943 if (uap->olddelta && error == 0) 944 error = copyout(&olddelta, uap->olddelta, sizeof(olddelta)); 945 return (error); 946 } 947 948 int 949 kern_adjtime(struct thread *td, struct timeval *delta, struct timeval *olddelta) 950 { 951 struct timeval atv; 952 int error; 953 954 mtx_lock(&Giant); 955 if (olddelta) { 956 atv.tv_sec = time_adjtime / 1000000; 957 atv.tv_usec = time_adjtime % 1000000; 958 if (atv.tv_usec < 0) { 959 atv.tv_usec += 1000000; 960 atv.tv_sec--; 961 } 962 *olddelta = atv; 963 } 964 if (delta) { 965 if ((error = priv_check(td, PRIV_ADJTIME))) { 966 mtx_unlock(&Giant); 967 return (error); 968 } 969 time_adjtime = (int64_t)delta->tv_sec * 1000000 + 970 delta->tv_usec; 971 } 972 mtx_unlock(&Giant); 973 return (0); 974 } 975 976 static struct callout resettodr_callout; 977 static int resettodr_period = 1800; 978 979 static void 980 periodic_resettodr(void *arg __unused) 981 { 982 983 if (!ntp_is_time_error()) { 984 mtx_lock(&Giant); 985 resettodr(); 986 mtx_unlock(&Giant); 987 } 988 if (resettodr_period > 0) 989 callout_schedule(&resettodr_callout, resettodr_period * hz); 990 } 991 992 static void 993 shutdown_resettodr(void *arg __unused, int howto __unused) 994 { 995 996 callout_drain(&resettodr_callout); 997 if (resettodr_period > 0 && !ntp_is_time_error()) { 998 mtx_lock(&Giant); 999 resettodr(); 1000 mtx_unlock(&Giant); 1001 } 1002 } 1003 1004 static int 1005 sysctl_resettodr_period(SYSCTL_HANDLER_ARGS) 1006 { 1007 int error; 1008 1009 error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req); 1010 if (error || !req->newptr) 1011 return (error); 1012 if (resettodr_period == 0) 1013 callout_stop(&resettodr_callout); 1014 else 1015 callout_reset(&resettodr_callout, resettodr_period * hz, 1016 periodic_resettodr, NULL); 1017 return (0); 1018 } 1019 1020 SYSCTL_PROC(_machdep, OID_AUTO, rtc_save_period, CTLTYPE_INT|CTLFLAG_RW, 1021 &resettodr_period, 1800, sysctl_resettodr_period, "I", 1022 "Save system time to RTC with this period (in seconds)"); 1023 TUNABLE_INT("machdep.rtc_save_period", &resettodr_period); 1024 1025 static void 1026 start_periodic_resettodr(void *arg __unused) 1027 { 1028 1029 EVENTHANDLER_REGISTER(shutdown_pre_sync, shutdown_resettodr, NULL, 1030 SHUTDOWN_PRI_FIRST); 1031 callout_init(&resettodr_callout, 1); 1032 if (resettodr_period == 0) 1033 return; 1034 callout_reset(&resettodr_callout, resettodr_period * hz, 1035 periodic_resettodr, NULL); 1036 } 1037 1038 SYSINIT(periodic_resettodr, SI_SUB_RUN_SCHEDULER, SI_ORDER_MIDDLE, 1039 start_periodic_resettodr, NULL); 1040