1 /* $NetBSD: kern_ntptime.c,v 1.46 2008/01/20 18:09:11 joerg Exp $ */ 2 3 /*- 4 *********************************************************************** 5 * * 6 * Copyright (c) David L. Mills 1993-2001 * 7 * * 8 * Permission to use, copy, modify, and distribute this software and * 9 * its documentation for any purpose and without fee is hereby * 10 * granted, provided that the above copyright notice appears in all * 11 * copies and that both the copyright notice and this permission * 12 * notice appear in supporting documentation, and that the name * 13 * University of Delaware not be used in advertising or publicity * 14 * pertaining to distribution of the software without specific, * 15 * written prior permission. The University of Delaware makes no * 16 * representations about the suitability this software for any * 17 * purpose. It is provided "as is" without express or implied * 18 * warranty. * 19 * * 20 **********************************************************************/ 21 22 /* 23 * Adapted from the original sources for FreeBSD and timecounters by: 24 * Poul-Henning Kamp <phk@FreeBSD.org>. 25 * 26 * The 32bit version of the "LP" macros seems a bit past its "sell by" 27 * date so I have retained only the 64bit version and included it directly 28 * in this file. 29 * 30 * Only minor changes done to interface with the timecounters over in 31 * sys/kern/kern_clock.c. Some of the comments below may be (even more) 32 * confusing and/or plain wrong in that context. 33 */ 34 35 #include <sys/cdefs.h> 36 /* __FBSDID("$FreeBSD: src/sys/kern/kern_ntptime.c,v 1.59 2005/05/28 14:34:41 rwatson Exp $"); */ 37 __KERNEL_RCSID(0, "$NetBSD: kern_ntptime.c,v 1.46 2008/01/20 18:09:11 joerg Exp $"); 38 39 #include "opt_ntp.h" 40 #include "opt_compat_netbsd.h" 41 42 #include <sys/param.h> 43 #include <sys/resourcevar.h> 44 #include <sys/systm.h> 45 #include <sys/kernel.h> 46 #include <sys/proc.h> 47 #include <sys/sysctl.h> 48 #include <sys/timex.h> 49 #ifdef COMPAT_30 50 #include <compat/sys/timex.h> 51 #endif 52 #include <sys/vnode.h> 53 #include <sys/kauth.h> 54 55 #include <sys/mount.h> 56 #include <sys/syscallargs.h> 57 58 #include <sys/cpu.h> 59 60 /* 61 * Single-precision macros for 64-bit machines 62 */ 63 typedef int64_t l_fp; 64 #define L_ADD(v, u) ((v) += (u)) 65 #define L_SUB(v, u) ((v) -= (u)) 66 #define L_ADDHI(v, a) ((v) += (int64_t)(a) << 32) 67 #define L_NEG(v) ((v) = -(v)) 68 #define L_RSHIFT(v, n) \ 69 do { \ 70 if ((v) < 0) \ 71 (v) = -(-(v) >> (n)); \ 72 else \ 73 (v) = (v) >> (n); \ 74 } while (0) 75 #define L_MPY(v, a) ((v) *= (a)) 76 #define L_CLR(v) ((v) = 0) 77 #define L_ISNEG(v) ((v) < 0) 78 #define L_LINT(v, a) ((v) = (int64_t)(a) << 32) 79 #define L_GINT(v) ((v) < 0 ? -(-(v) >> 32) : (v) >> 32) 80 81 #ifdef NTP 82 /* 83 * Generic NTP kernel interface 84 * 85 * These routines constitute the Network Time Protocol (NTP) interfaces 86 * for user and daemon application programs. The ntp_gettime() routine 87 * provides the time, maximum error (synch distance) and estimated error 88 * (dispersion) to client user application programs. The ntp_adjtime() 89 * routine is used by the NTP daemon to adjust the system clock to an 90 * externally derived time. The time offset and related variables set by 91 * this routine are used by other routines in this module to adjust the 92 * phase and frequency of the clock discipline loop which controls the 93 * system clock. 94 * 95 * When the kernel time is reckoned directly in nanoseconds (NTP_NANO 96 * defined), the time at each tick interrupt is derived directly from 97 * the kernel time variable. When the kernel time is reckoned in 98 * microseconds, (NTP_NANO undefined), the time is derived from the 99 * kernel time variable together with a variable representing the 100 * leftover nanoseconds at the last tick interrupt. In either case, the 101 * current nanosecond time is reckoned from these values plus an 102 * interpolated value derived by the clock routines in another 103 * architecture-specific module. The interpolation can use either a 104 * dedicated counter or a processor cycle counter (PCC) implemented in 105 * some architectures. 106 * 107 * Note that all routines must run at priority splclock or higher. 108 */ 109 /* 110 * Phase/frequency-lock loop (PLL/FLL) definitions 111 * 112 * The nanosecond clock discipline uses two variable types, time 113 * variables and frequency variables. Both types are represented as 64- 114 * bit fixed-point quantities with the decimal point between two 32-bit 115 * halves. On a 32-bit machine, each half is represented as a single 116 * word and mathematical operations are done using multiple-precision 117 * arithmetic. On a 64-bit machine, ordinary computer arithmetic is 118 * used. 119 * 120 * A time variable is a signed 64-bit fixed-point number in ns and 121 * fraction. It represents the remaining time offset to be amortized 122 * over succeeding tick interrupts. The maximum time offset is about 123 * 0.5 s and the resolution is about 2.3e-10 ns. 124 * 125 * 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 126 * 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 1 127 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 128 * |s s s| ns | 129 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 130 * | fraction | 131 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 132 * 133 * A frequency variable is a signed 64-bit fixed-point number in ns/s 134 * and fraction. It represents the ns and fraction to be added to the 135 * kernel time variable at each second. The maximum frequency offset is 136 * about +-500000 ns/s and the resolution is about 2.3e-10 ns/s. 137 * 138 * 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 139 * 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 1 140 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 141 * |s s s s s s s s s s s s s| ns/s | 142 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 143 * | fraction | 144 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 145 */ 146 /* 147 * The following variables establish the state of the PLL/FLL and the 148 * residual time and frequency offset of the local clock. 149 */ 150 #define SHIFT_PLL 4 /* PLL loop gain (shift) */ 151 #define SHIFT_FLL 2 /* FLL loop gain (shift) */ 152 153 static int time_state = TIME_OK; /* clock state */ 154 static int time_status = STA_UNSYNC; /* clock status bits */ 155 static long time_tai; /* TAI offset (s) */ 156 static long time_monitor; /* last time offset scaled (ns) */ 157 static long time_constant; /* poll interval (shift) (s) */ 158 static long time_precision = 1; /* clock precision (ns) */ 159 static long time_maxerror = MAXPHASE / 1000; /* maximum error (us) */ 160 static long time_esterror = MAXPHASE / 1000; /* estimated error (us) */ 161 static long time_reftime; /* time at last adjustment (s) */ 162 static l_fp time_offset; /* time offset (ns) */ 163 static l_fp time_freq; /* frequency offset (ns/s) */ 164 #endif /* NTP */ 165 166 static l_fp time_adj; /* tick adjust (ns/s) */ 167 int64_t time_adjtime; /* correction from adjtime(2) (usec) */ 168 169 extern int time_adjusted; /* ntp might have changed the system time */ 170 171 #ifdef NTP 172 #ifdef PPS_SYNC 173 /* 174 * The following variables are used when a pulse-per-second (PPS) signal 175 * is available and connected via a modem control lead. They establish 176 * the engineering parameters of the clock discipline loop when 177 * controlled by the PPS signal. 178 */ 179 #define PPS_FAVG 2 /* min freq avg interval (s) (shift) */ 180 #define PPS_FAVGDEF 8 /* default freq avg int (s) (shift) */ 181 #define PPS_FAVGMAX 15 /* max freq avg interval (s) (shift) */ 182 #define PPS_PAVG 4 /* phase avg interval (s) (shift) */ 183 #define PPS_VALID 120 /* PPS signal watchdog max (s) */ 184 #define PPS_MAXWANDER 100000 /* max PPS wander (ns/s) */ 185 #define PPS_POPCORN 2 /* popcorn spike threshold (shift) */ 186 187 static struct timespec pps_tf[3]; /* phase median filter */ 188 static l_fp pps_freq; /* scaled frequency offset (ns/s) */ 189 static long pps_fcount; /* frequency accumulator */ 190 static long pps_jitter; /* nominal jitter (ns) */ 191 static long pps_stabil; /* nominal stability (scaled ns/s) */ 192 static long pps_lastsec; /* time at last calibration (s) */ 193 static int pps_valid; /* signal watchdog counter */ 194 static int pps_shift = PPS_FAVG; /* interval duration (s) (shift) */ 195 static int pps_shiftmax = PPS_FAVGDEF; /* max interval duration (s) (shift) */ 196 static int pps_intcnt; /* wander counter */ 197 198 /* 199 * PPS signal quality monitors 200 */ 201 static long pps_calcnt; /* calibration intervals */ 202 static long pps_jitcnt; /* jitter limit exceeded */ 203 static long pps_stbcnt; /* stability limit exceeded */ 204 static long pps_errcnt; /* calibration errors */ 205 #endif /* PPS_SYNC */ 206 /* 207 * End of phase/frequency-lock loop (PLL/FLL) definitions 208 */ 209 210 static void hardupdate(long offset); 211 212 /* 213 * ntp_gettime() - NTP user application interface 214 */ 215 void 216 ntp_gettime(struct ntptimeval *ntv) 217 { 218 nanotime(&ntv->time); 219 ntv->maxerror = time_maxerror; 220 ntv->esterror = time_esterror; 221 ntv->tai = time_tai; 222 ntv->time_state = time_state; 223 } 224 225 /* ARGSUSED */ 226 /* 227 * ntp_adjtime() - NTP daemon application interface 228 */ 229 int 230 sys_ntp_adjtime(struct lwp *l, const struct sys_ntp_adjtime_args *uap, register_t *retval) 231 { 232 /* { 233 syscallarg(struct timex *) tp; 234 } */ 235 struct timex ntv; 236 int error = 0; 237 238 error = copyin((void *)SCARG(uap, tp), (void *)&ntv, sizeof(ntv)); 239 if (error != 0) 240 return (error); 241 242 if (ntv.modes != 0 && (error = kauth_authorize_system(l->l_cred, 243 KAUTH_SYSTEM_TIME, KAUTH_REQ_SYSTEM_TIME_NTPADJTIME, NULL, 244 NULL, NULL)) != 0) 245 return (error); 246 247 ntp_adjtime1(&ntv); 248 249 error = copyout((void *)&ntv, (void *)SCARG(uap, tp), sizeof(ntv)); 250 if (!error) 251 *retval = ntp_timestatus(); 252 253 return error; 254 } 255 256 void 257 ntp_adjtime1(struct timex *ntv) 258 { 259 long freq; 260 int modes; 261 int s; 262 263 /* 264 * Update selected clock variables - only the superuser can 265 * change anything. Note that there is no error checking here on 266 * the assumption the superuser should know what it is doing. 267 * Note that either the time constant or TAI offset are loaded 268 * from the ntv.constant member, depending on the mode bits. If 269 * the STA_PLL bit in the status word is cleared, the state and 270 * status words are reset to the initial values at boot. 271 */ 272 modes = ntv->modes; 273 if (modes != 0) 274 /* We need to save the system time during shutdown */ 275 time_adjusted |= 2; 276 s = splclock(); 277 if (modes & MOD_MAXERROR) 278 time_maxerror = ntv->maxerror; 279 if (modes & MOD_ESTERROR) 280 time_esterror = ntv->esterror; 281 if (modes & MOD_STATUS) { 282 if (time_status & STA_PLL && !(ntv->status & STA_PLL)) { 283 time_state = TIME_OK; 284 time_status = STA_UNSYNC; 285 #ifdef PPS_SYNC 286 pps_shift = PPS_FAVG; 287 #endif /* PPS_SYNC */ 288 } 289 time_status &= STA_RONLY; 290 time_status |= ntv->status & ~STA_RONLY; 291 } 292 if (modes & MOD_TIMECONST) { 293 if (ntv->constant < 0) 294 time_constant = 0; 295 else if (ntv->constant > MAXTC) 296 time_constant = MAXTC; 297 else 298 time_constant = ntv->constant; 299 } 300 if (modes & MOD_TAI) { 301 if (ntv->constant > 0) /* XXX zero & negative numbers ? */ 302 time_tai = ntv->constant; 303 } 304 #ifdef PPS_SYNC 305 if (modes & MOD_PPSMAX) { 306 if (ntv->shift < PPS_FAVG) 307 pps_shiftmax = PPS_FAVG; 308 else if (ntv->shift > PPS_FAVGMAX) 309 pps_shiftmax = PPS_FAVGMAX; 310 else 311 pps_shiftmax = ntv->shift; 312 } 313 #endif /* PPS_SYNC */ 314 if (modes & MOD_NANO) 315 time_status |= STA_NANO; 316 if (modes & MOD_MICRO) 317 time_status &= ~STA_NANO; 318 if (modes & MOD_CLKB) 319 time_status |= STA_CLK; 320 if (modes & MOD_CLKA) 321 time_status &= ~STA_CLK; 322 if (modes & MOD_FREQUENCY) { 323 freq = (ntv->freq * 1000LL) >> 16; 324 if (freq > MAXFREQ) 325 L_LINT(time_freq, MAXFREQ); 326 else if (freq < -MAXFREQ) 327 L_LINT(time_freq, -MAXFREQ); 328 else { 329 /* 330 * ntv.freq is [PPM * 2^16] = [us/s * 2^16] 331 * time_freq is [ns/s * 2^32] 332 */ 333 time_freq = ntv->freq * 1000LL * 65536LL; 334 } 335 #ifdef PPS_SYNC 336 pps_freq = time_freq; 337 #endif /* PPS_SYNC */ 338 } 339 if (modes & MOD_OFFSET) { 340 if (time_status & STA_NANO) 341 hardupdate(ntv->offset); 342 else 343 hardupdate(ntv->offset * 1000); 344 } 345 346 /* 347 * Retrieve all clock variables. Note that the TAI offset is 348 * returned only by ntp_gettime(); 349 */ 350 if (time_status & STA_NANO) 351 ntv->offset = L_GINT(time_offset); 352 else 353 ntv->offset = L_GINT(time_offset) / 1000; /* XXX rounding ? */ 354 ntv->freq = L_GINT((time_freq / 1000LL) << 16); 355 ntv->maxerror = time_maxerror; 356 ntv->esterror = time_esterror; 357 ntv->status = time_status; 358 ntv->constant = time_constant; 359 if (time_status & STA_NANO) 360 ntv->precision = time_precision; 361 else 362 ntv->precision = time_precision / 1000; 363 ntv->tolerance = MAXFREQ * SCALE_PPM; 364 #ifdef PPS_SYNC 365 ntv->shift = pps_shift; 366 ntv->ppsfreq = L_GINT((pps_freq / 1000LL) << 16); 367 if (time_status & STA_NANO) 368 ntv->jitter = pps_jitter; 369 else 370 ntv->jitter = pps_jitter / 1000; 371 ntv->stabil = pps_stabil; 372 ntv->calcnt = pps_calcnt; 373 ntv->errcnt = pps_errcnt; 374 ntv->jitcnt = pps_jitcnt; 375 ntv->stbcnt = pps_stbcnt; 376 #endif /* PPS_SYNC */ 377 splx(s); 378 } 379 #endif /* NTP */ 380 381 /* 382 * second_overflow() - called after ntp_tick_adjust() 383 * 384 * This routine is ordinarily called immediately following the above 385 * routine ntp_tick_adjust(). While these two routines are normally 386 * combined, they are separated here only for the purposes of 387 * simulation. 388 */ 389 void 390 ntp_update_second(int64_t *adjustment, time_t *newsec) 391 { 392 int tickrate; 393 l_fp ftemp; /* 32/64-bit temporary */ 394 395 #ifdef NTP 396 397 /* 398 * On rollover of the second both the nanosecond and microsecond 399 * clocks are updated and the state machine cranked as 400 * necessary. The phase adjustment to be used for the next 401 * second is calculated and the maximum error is increased by 402 * the tolerance. 403 */ 404 time_maxerror += MAXFREQ / 1000; 405 406 /* 407 * Leap second processing. If in leap-insert state at 408 * the end of the day, the system clock is set back one 409 * second; if in leap-delete state, the system clock is 410 * set ahead one second. The nano_time() routine or 411 * external clock driver will insure that reported time 412 * is always monotonic. 413 */ 414 switch (time_state) { 415 416 /* 417 * No warning. 418 */ 419 case TIME_OK: 420 if (time_status & STA_INS) 421 time_state = TIME_INS; 422 else if (time_status & STA_DEL) 423 time_state = TIME_DEL; 424 break; 425 426 /* 427 * Insert second 23:59:60 following second 428 * 23:59:59. 429 */ 430 case TIME_INS: 431 if (!(time_status & STA_INS)) 432 time_state = TIME_OK; 433 else if ((*newsec) % 86400 == 0) { 434 (*newsec)--; 435 time_state = TIME_OOP; 436 time_tai++; 437 } 438 break; 439 440 /* 441 * Delete second 23:59:59. 442 */ 443 case TIME_DEL: 444 if (!(time_status & STA_DEL)) 445 time_state = TIME_OK; 446 else if (((*newsec) + 1) % 86400 == 0) { 447 (*newsec)++; 448 time_tai--; 449 time_state = TIME_WAIT; 450 } 451 break; 452 453 /* 454 * Insert second in progress. 455 */ 456 case TIME_OOP: 457 time_state = TIME_WAIT; 458 break; 459 460 /* 461 * Wait for status bits to clear. 462 */ 463 case TIME_WAIT: 464 if (!(time_status & (STA_INS | STA_DEL))) 465 time_state = TIME_OK; 466 } 467 468 /* 469 * Compute the total time adjustment for the next second 470 * in ns. The offset is reduced by a factor depending on 471 * whether the PPS signal is operating. Note that the 472 * value is in effect scaled by the clock frequency, 473 * since the adjustment is added at each tick interrupt. 474 */ 475 ftemp = time_offset; 476 #ifdef PPS_SYNC 477 /* XXX even if PPS signal dies we should finish adjustment ? */ 478 if (time_status & STA_PPSTIME && time_status & 479 STA_PPSSIGNAL) 480 L_RSHIFT(ftemp, pps_shift); 481 else 482 L_RSHIFT(ftemp, SHIFT_PLL + time_constant); 483 #else 484 L_RSHIFT(ftemp, SHIFT_PLL + time_constant); 485 #endif /* PPS_SYNC */ 486 time_adj = ftemp; 487 L_SUB(time_offset, ftemp); 488 L_ADD(time_adj, time_freq); 489 490 #ifdef PPS_SYNC 491 if (pps_valid > 0) 492 pps_valid--; 493 else 494 time_status &= ~STA_PPSSIGNAL; 495 #endif /* PPS_SYNC */ 496 #else /* !NTP */ 497 L_CLR(time_adj); 498 #endif /* !NTP */ 499 500 /* 501 * Apply any correction from adjtime(2). If more than one second 502 * off we slew at a rate of 5ms/s (5000 PPM) else 500us/s (500PPM) 503 * until the last second is slewed the final < 500 usecs. 504 */ 505 if (time_adjtime != 0) { 506 if (time_adjtime > 1000000) 507 tickrate = 5000; 508 else if (time_adjtime < -1000000) 509 tickrate = -5000; 510 else if (time_adjtime > 500) 511 tickrate = 500; 512 else if (time_adjtime < -500) 513 tickrate = -500; 514 else 515 tickrate = time_adjtime; 516 time_adjtime -= tickrate; 517 L_LINT(ftemp, tickrate * 1000); 518 L_ADD(time_adj, ftemp); 519 } 520 *adjustment = time_adj; 521 } 522 523 /* 524 * ntp_init() - initialize variables and structures 525 * 526 * This routine must be called after the kernel variables hz and tick 527 * are set or changed and before the next tick interrupt. In this 528 * particular implementation, these values are assumed set elsewhere in 529 * the kernel. The design allows the clock frequency and tick interval 530 * to be changed while the system is running. So, this routine should 531 * probably be integrated with the code that does that. 532 */ 533 void 534 ntp_init(void) 535 { 536 537 /* 538 * The following variables are initialized only at startup. Only 539 * those structures not cleared by the compiler need to be 540 * initialized, and these only in the simulator. In the actual 541 * kernel, any nonzero values here will quickly evaporate. 542 */ 543 L_CLR(time_adj); 544 #ifdef NTP 545 L_CLR(time_offset); 546 L_CLR(time_freq); 547 #ifdef PPS_SYNC 548 pps_tf[0].tv_sec = pps_tf[0].tv_nsec = 0; 549 pps_tf[1].tv_sec = pps_tf[1].tv_nsec = 0; 550 pps_tf[2].tv_sec = pps_tf[2].tv_nsec = 0; 551 pps_fcount = 0; 552 L_CLR(pps_freq); 553 #endif /* PPS_SYNC */ 554 #endif 555 } 556 557 #ifdef NTP 558 /* 559 * hardupdate() - local clock update 560 * 561 * This routine is called by ntp_adjtime() to update the local clock 562 * phase and frequency. The implementation is of an adaptive-parameter, 563 * hybrid phase/frequency-lock loop (PLL/FLL). The routine computes new 564 * time and frequency offset estimates for each call. If the kernel PPS 565 * discipline code is configured (PPS_SYNC), the PPS signal itself 566 * determines the new time offset, instead of the calling argument. 567 * Presumably, calls to ntp_adjtime() occur only when the caller 568 * believes the local clock is valid within some bound (+-128 ms with 569 * NTP). If the caller's time is far different than the PPS time, an 570 * argument will ensue, and it's not clear who will lose. 571 * 572 * For uncompensated quartz crystal oscillators and nominal update 573 * intervals less than 256 s, operation should be in phase-lock mode, 574 * where the loop is disciplined to phase. For update intervals greater 575 * than 1024 s, operation should be in frequency-lock mode, where the 576 * loop is disciplined to frequency. Between 256 s and 1024 s, the mode 577 * is selected by the STA_MODE status bit. 578 * 579 * Note: splclock() is in effect. 580 */ 581 void 582 hardupdate(long offset) 583 { 584 long mtemp; 585 l_fp ftemp; 586 587 /* 588 * Select how the phase is to be controlled and from which 589 * source. If the PPS signal is present and enabled to 590 * discipline the time, the PPS offset is used; otherwise, the 591 * argument offset is used. 592 */ 593 if (!(time_status & STA_PLL)) 594 return; 595 if (!(time_status & STA_PPSTIME && time_status & 596 STA_PPSSIGNAL)) { 597 if (offset > MAXPHASE) 598 time_monitor = MAXPHASE; 599 else if (offset < -MAXPHASE) 600 time_monitor = -MAXPHASE; 601 else 602 time_monitor = offset; 603 L_LINT(time_offset, time_monitor); 604 } 605 606 /* 607 * Select how the frequency is to be controlled and in which 608 * mode (PLL or FLL). If the PPS signal is present and enabled 609 * to discipline the frequency, the PPS frequency is used; 610 * otherwise, the argument offset is used to compute it. 611 */ 612 if (time_status & STA_PPSFREQ && time_status & STA_PPSSIGNAL) { 613 time_reftime = time_second; 614 return; 615 } 616 if (time_status & STA_FREQHOLD || time_reftime == 0) 617 time_reftime = time_second; 618 mtemp = time_second - time_reftime; 619 L_LINT(ftemp, time_monitor); 620 L_RSHIFT(ftemp, (SHIFT_PLL + 2 + time_constant) << 1); 621 L_MPY(ftemp, mtemp); 622 L_ADD(time_freq, ftemp); 623 time_status &= ~STA_MODE; 624 if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > 625 MAXSEC)) { 626 L_LINT(ftemp, (time_monitor << 4) / mtemp); 627 L_RSHIFT(ftemp, SHIFT_FLL + 4); 628 L_ADD(time_freq, ftemp); 629 time_status |= STA_MODE; 630 } 631 time_reftime = time_second; 632 if (L_GINT(time_freq) > MAXFREQ) 633 L_LINT(time_freq, MAXFREQ); 634 else if (L_GINT(time_freq) < -MAXFREQ) 635 L_LINT(time_freq, -MAXFREQ); 636 } 637 638 #ifdef PPS_SYNC 639 /* 640 * hardpps() - discipline CPU clock oscillator to external PPS signal 641 * 642 * This routine is called at each PPS interrupt in order to discipline 643 * the CPU clock oscillator to the PPS signal. It measures the PPS phase 644 * and leaves it in a handy spot for the hardclock() routine. It 645 * integrates successive PPS phase differences and calculates the 646 * frequency offset. This is used in hardclock() to discipline the CPU 647 * clock oscillator so that intrinsic frequency error is cancelled out. 648 * The code requires the caller to capture the time and hardware counter 649 * value at the on-time PPS signal transition. 650 * 651 * Note that, on some Unix systems, this routine runs at an interrupt 652 * priority level higher than the timer interrupt routine hardclock(). 653 * Therefore, the variables used are distinct from the hardclock() 654 * variables, except for certain exceptions: The PPS frequency pps_freq 655 * and phase pps_offset variables are determined by this routine and 656 * updated atomically. The time_tolerance variable can be considered a 657 * constant, since it is infrequently changed, and then only when the 658 * PPS signal is disabled. The watchdog counter pps_valid is updated 659 * once per second by hardclock() and is atomically cleared in this 660 * routine. 661 */ 662 void 663 hardpps(struct timespec *tsp, /* time at PPS */ 664 long nsec /* hardware counter at PPS */) 665 { 666 long u_sec, u_nsec, v_nsec; /* temps */ 667 l_fp ftemp; 668 669 /* 670 * The signal is first processed by a range gate and frequency 671 * discriminator. The range gate rejects noise spikes outside 672 * the range +-500 us. The frequency discriminator rejects input 673 * signals with apparent frequency outside the range 1 +-500 674 * PPM. If two hits occur in the same second, we ignore the 675 * later hit; if not and a hit occurs outside the range gate, 676 * keep the later hit for later comparison, but do not process 677 * it. 678 */ 679 time_status |= STA_PPSSIGNAL | STA_PPSJITTER; 680 time_status &= ~(STA_PPSWANDER | STA_PPSERROR); 681 pps_valid = PPS_VALID; 682 u_sec = tsp->tv_sec; 683 u_nsec = tsp->tv_nsec; 684 if (u_nsec >= (NANOSECOND >> 1)) { 685 u_nsec -= NANOSECOND; 686 u_sec++; 687 } 688 v_nsec = u_nsec - pps_tf[0].tv_nsec; 689 if (u_sec == pps_tf[0].tv_sec && v_nsec < NANOSECOND - 690 MAXFREQ) 691 return; 692 pps_tf[2] = pps_tf[1]; 693 pps_tf[1] = pps_tf[0]; 694 pps_tf[0].tv_sec = u_sec; 695 pps_tf[0].tv_nsec = u_nsec; 696 697 /* 698 * Compute the difference between the current and previous 699 * counter values. If the difference exceeds 0.5 s, assume it 700 * has wrapped around, so correct 1.0 s. If the result exceeds 701 * the tick interval, the sample point has crossed a tick 702 * boundary during the last second, so correct the tick. Very 703 * intricate. 704 */ 705 u_nsec = nsec; 706 if (u_nsec > (NANOSECOND >> 1)) 707 u_nsec -= NANOSECOND; 708 else if (u_nsec < -(NANOSECOND >> 1)) 709 u_nsec += NANOSECOND; 710 pps_fcount += u_nsec; 711 if (v_nsec > MAXFREQ || v_nsec < -MAXFREQ) 712 return; 713 time_status &= ~STA_PPSJITTER; 714 715 /* 716 * A three-stage median filter is used to help denoise the PPS 717 * time. The median sample becomes the time offset estimate; the 718 * difference between the other two samples becomes the time 719 * dispersion (jitter) estimate. 720 */ 721 if (pps_tf[0].tv_nsec > pps_tf[1].tv_nsec) { 722 if (pps_tf[1].tv_nsec > pps_tf[2].tv_nsec) { 723 v_nsec = pps_tf[1].tv_nsec; /* 0 1 2 */ 724 u_nsec = pps_tf[0].tv_nsec - pps_tf[2].tv_nsec; 725 } else if (pps_tf[2].tv_nsec > pps_tf[0].tv_nsec) { 726 v_nsec = pps_tf[0].tv_nsec; /* 2 0 1 */ 727 u_nsec = pps_tf[2].tv_nsec - pps_tf[1].tv_nsec; 728 } else { 729 v_nsec = pps_tf[2].tv_nsec; /* 0 2 1 */ 730 u_nsec = pps_tf[0].tv_nsec - pps_tf[1].tv_nsec; 731 } 732 } else { 733 if (pps_tf[1].tv_nsec < pps_tf[2].tv_nsec) { 734 v_nsec = pps_tf[1].tv_nsec; /* 2 1 0 */ 735 u_nsec = pps_tf[2].tv_nsec - pps_tf[0].tv_nsec; 736 } else if (pps_tf[2].tv_nsec < pps_tf[0].tv_nsec) { 737 v_nsec = pps_tf[0].tv_nsec; /* 1 0 2 */ 738 u_nsec = pps_tf[1].tv_nsec - pps_tf[2].tv_nsec; 739 } else { 740 v_nsec = pps_tf[2].tv_nsec; /* 1 2 0 */ 741 u_nsec = pps_tf[1].tv_nsec - pps_tf[0].tv_nsec; 742 } 743 } 744 745 /* 746 * Nominal jitter is due to PPS signal noise and interrupt 747 * latency. If it exceeds the popcorn threshold, the sample is 748 * discarded. otherwise, if so enabled, the time offset is 749 * updated. We can tolerate a modest loss of data here without 750 * much degrading time accuracy. 751 */ 752 if (u_nsec > (pps_jitter << PPS_POPCORN)) { 753 time_status |= STA_PPSJITTER; 754 pps_jitcnt++; 755 } else if (time_status & STA_PPSTIME) { 756 time_monitor = -v_nsec; 757 L_LINT(time_offset, time_monitor); 758 } 759 pps_jitter += (u_nsec - pps_jitter) >> PPS_FAVG; 760 u_sec = pps_tf[0].tv_sec - pps_lastsec; 761 if (u_sec < (1 << pps_shift)) 762 return; 763 764 /* 765 * At the end of the calibration interval the difference between 766 * the first and last counter values becomes the scaled 767 * frequency. It will later be divided by the length of the 768 * interval to determine the frequency update. If the frequency 769 * exceeds a sanity threshold, or if the actual calibration 770 * interval is not equal to the expected length, the data are 771 * discarded. We can tolerate a modest loss of data here without 772 * much degrading frequency accuracy. 773 */ 774 pps_calcnt++; 775 v_nsec = -pps_fcount; 776 pps_lastsec = pps_tf[0].tv_sec; 777 pps_fcount = 0; 778 u_nsec = MAXFREQ << pps_shift; 779 if (v_nsec > u_nsec || v_nsec < -u_nsec || u_sec != (1 << 780 pps_shift)) { 781 time_status |= STA_PPSERROR; 782 pps_errcnt++; 783 return; 784 } 785 786 /* 787 * Here the raw frequency offset and wander (stability) is 788 * calculated. If the wander is less than the wander threshold 789 * for four consecutive averaging intervals, the interval is 790 * doubled; if it is greater than the threshold for four 791 * consecutive intervals, the interval is halved. The scaled 792 * frequency offset is converted to frequency offset. The 793 * stability metric is calculated as the average of recent 794 * frequency changes, but is used only for performance 795 * monitoring. 796 */ 797 L_LINT(ftemp, v_nsec); 798 L_RSHIFT(ftemp, pps_shift); 799 L_SUB(ftemp, pps_freq); 800 u_nsec = L_GINT(ftemp); 801 if (u_nsec > PPS_MAXWANDER) { 802 L_LINT(ftemp, PPS_MAXWANDER); 803 pps_intcnt--; 804 time_status |= STA_PPSWANDER; 805 pps_stbcnt++; 806 } else if (u_nsec < -PPS_MAXWANDER) { 807 L_LINT(ftemp, -PPS_MAXWANDER); 808 pps_intcnt--; 809 time_status |= STA_PPSWANDER; 810 pps_stbcnt++; 811 } else { 812 pps_intcnt++; 813 } 814 if (pps_intcnt >= 4) { 815 pps_intcnt = 4; 816 if (pps_shift < pps_shiftmax) { 817 pps_shift++; 818 pps_intcnt = 0; 819 } 820 } else if (pps_intcnt <= -4 || pps_shift > pps_shiftmax) { 821 pps_intcnt = -4; 822 if (pps_shift > PPS_FAVG) { 823 pps_shift--; 824 pps_intcnt = 0; 825 } 826 } 827 if (u_nsec < 0) 828 u_nsec = -u_nsec; 829 pps_stabil += (u_nsec * SCALE_PPM - pps_stabil) >> PPS_FAVG; 830 831 /* 832 * The PPS frequency is recalculated and clamped to the maximum 833 * MAXFREQ. If enabled, the system clock frequency is updated as 834 * well. 835 */ 836 L_ADD(pps_freq, ftemp); 837 u_nsec = L_GINT(pps_freq); 838 if (u_nsec > MAXFREQ) 839 L_LINT(pps_freq, MAXFREQ); 840 else if (u_nsec < -MAXFREQ) 841 L_LINT(pps_freq, -MAXFREQ); 842 if (time_status & STA_PPSFREQ) 843 time_freq = pps_freq; 844 } 845 #endif /* PPS_SYNC */ 846 #endif /* NTP */ 847 848 #ifdef NTP 849 int 850 ntp_timestatus() 851 { 852 /* 853 * Status word error decode. If any of these conditions 854 * occur, an error is returned, instead of the status 855 * word. Most applications will care only about the fact 856 * the system clock may not be trusted, not about the 857 * details. 858 * 859 * Hardware or software error 860 */ 861 if ((time_status & (STA_UNSYNC | STA_CLOCKERR)) || 862 863 /* 864 * PPS signal lost when either time or frequency 865 * synchronization requested 866 */ 867 (time_status & (STA_PPSFREQ | STA_PPSTIME) && 868 !(time_status & STA_PPSSIGNAL)) || 869 870 /* 871 * PPS jitter exceeded when time synchronization 872 * requested 873 */ 874 (time_status & STA_PPSTIME && 875 time_status & STA_PPSJITTER) || 876 877 /* 878 * PPS wander exceeded or calibration error when 879 * frequency synchronization requested 880 */ 881 (time_status & STA_PPSFREQ && 882 time_status & (STA_PPSWANDER | STA_PPSERROR))) 883 return (TIME_ERROR); 884 else 885 return (time_state); 886 } 887 888 /*ARGSUSED*/ 889 /* 890 * ntp_gettime() - NTP user application interface 891 */ 892 int 893 sys___ntp_gettime30(struct lwp *l, const struct sys___ntp_gettime30_args *uap, register_t *retval) 894 { 895 /* { 896 syscallarg(struct ntptimeval *) ntvp; 897 } */ 898 struct ntptimeval ntv; 899 int error = 0; 900 901 if (SCARG(uap, ntvp)) { 902 ntp_gettime(&ntv); 903 904 error = copyout((void *)&ntv, (void *)SCARG(uap, ntvp), 905 sizeof(ntv)); 906 } 907 if (!error) { 908 *retval = ntp_timestatus(); 909 } 910 return(error); 911 } 912 913 #ifdef COMPAT_30 914 int 915 compat_30_sys_ntp_gettime(struct lwp *l, const struct compat_30_sys_ntp_gettime_args *uap, register_t *retval) 916 { 917 /* { 918 syscallarg(struct ntptimeval30 *) ontvp; 919 } */ 920 struct ntptimeval ntv; 921 struct ntptimeval30 ontv; 922 int error = 0; 923 924 if (SCARG(uap, ntvp)) { 925 ntp_gettime(&ntv); 926 TIMESPEC_TO_TIMEVAL(&ontv.time, &ntv.time); 927 ontv.maxerror = ntv.maxerror; 928 ontv.esterror = ntv.esterror; 929 930 error = copyout((void *)&ontv, (void *)SCARG(uap, ntvp), 931 sizeof(ontv)); 932 } 933 if (!error) 934 *retval = ntp_timestatus(); 935 936 return (error); 937 } 938 #endif 939 940 /* 941 * return information about kernel precision timekeeping 942 */ 943 static int 944 sysctl_kern_ntptime(SYSCTLFN_ARGS) 945 { 946 struct sysctlnode node; 947 struct ntptimeval ntv; 948 949 ntp_gettime(&ntv); 950 951 node = *rnode; 952 node.sysctl_data = &ntv; 953 node.sysctl_size = sizeof(ntv); 954 return (sysctl_lookup(SYSCTLFN_CALL(&node))); 955 } 956 957 SYSCTL_SETUP(sysctl_kern_ntptime_setup, "sysctl kern.ntptime node setup") 958 { 959 960 sysctl_createv(clog, 0, NULL, NULL, 961 CTLFLAG_PERMANENT, 962 CTLTYPE_NODE, "kern", NULL, 963 NULL, 0, NULL, 0, 964 CTL_KERN, CTL_EOL); 965 966 sysctl_createv(clog, 0, NULL, NULL, 967 CTLFLAG_PERMANENT, 968 CTLTYPE_STRUCT, "ntptime", 969 SYSCTL_DESCR("Kernel clock values for NTP"), 970 sysctl_kern_ntptime, 0, NULL, 971 sizeof(struct ntptimeval), 972 CTL_KERN, KERN_NTPTIME, CTL_EOL); 973 } 974 #else /* !NTP */ 975 /* For some reason, raising SIGSYS (as sys_nosys would) is problematic. */ 976 977 int 978 sys___ntp_gettime30(struct lwp *l, const struct sys___ntp_gettime30_args *uap, register_t *retval) 979 { 980 981 return(ENOSYS); 982 } 983 984 #ifdef COMPAT_30 985 int 986 compat_30_sys_ntp_gettime(struct lwp *l, const struct compat_30_sys_ntp_gettime_args *uap, register_t *retval) 987 { 988 989 return(ENOSYS); 990 } 991 #endif 992 #endif /* !NTP */ 993