1 /* $NetBSD: kern_ntptime.c,v 1.51 2009/01/11 02:45:52 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 /*- 30 *********************************************************************** 31 * * 32 * Copyright (c) David L. Mills 1993-2001 * 33 * * 34 * Permission to use, copy, modify, and distribute this software and * 35 * its documentation for any purpose and without fee is hereby * 36 * granted, provided that the above copyright notice appears in all * 37 * copies and that both the copyright notice and this permission * 38 * notice appear in supporting documentation, and that the name * 39 * University of Delaware not be used in advertising or publicity * 40 * pertaining to distribution of the software without specific, * 41 * written prior permission. The University of Delaware makes no * 42 * representations about the suitability this software for any * 43 * purpose. It is provided "as is" without express or implied * 44 * warranty. * 45 * * 46 **********************************************************************/ 47 48 /* 49 * Adapted from the original sources for FreeBSD and timecounters by: 50 * Poul-Henning Kamp <phk@FreeBSD.org>. 51 * 52 * The 32bit version of the "LP" macros seems a bit past its "sell by" 53 * date so I have retained only the 64bit version and included it directly 54 * in this file. 55 * 56 * Only minor changes done to interface with the timecounters over in 57 * sys/kern/kern_clock.c. Some of the comments below may be (even more) 58 * confusing and/or plain wrong in that context. 59 */ 60 61 #include <sys/cdefs.h> 62 /* __FBSDID("$FreeBSD: src/sys/kern/kern_ntptime.c,v 1.59 2005/05/28 14:34:41 rwatson Exp $"); */ 63 __KERNEL_RCSID(0, "$NetBSD: kern_ntptime.c,v 1.51 2009/01/11 02:45:52 christos Exp $"); 64 65 #include "opt_ntp.h" 66 67 #include <sys/param.h> 68 #include <sys/resourcevar.h> 69 #include <sys/systm.h> 70 #include <sys/kernel.h> 71 #include <sys/proc.h> 72 #include <sys/sysctl.h> 73 #include <sys/timex.h> 74 #include <sys/vnode.h> 75 #include <sys/kauth.h> 76 #include <sys/mount.h> 77 #include <sys/syscallargs.h> 78 #include <sys/cpu.h> 79 80 #include <compat/sys/timex.h> 81 82 /* 83 * Single-precision macros for 64-bit machines 84 */ 85 typedef int64_t l_fp; 86 #define L_ADD(v, u) ((v) += (u)) 87 #define L_SUB(v, u) ((v) -= (u)) 88 #define L_ADDHI(v, a) ((v) += (int64_t)(a) << 32) 89 #define L_NEG(v) ((v) = -(v)) 90 #define L_RSHIFT(v, n) \ 91 do { \ 92 if ((v) < 0) \ 93 (v) = -(-(v) >> (n)); \ 94 else \ 95 (v) = (v) >> (n); \ 96 } while (0) 97 #define L_MPY(v, a) ((v) *= (a)) 98 #define L_CLR(v) ((v) = 0) 99 #define L_ISNEG(v) ((v) < 0) 100 #define L_LINT(v, a) ((v) = (int64_t)(a) << 32) 101 #define L_GINT(v) ((v) < 0 ? -(-(v) >> 32) : (v) >> 32) 102 103 #ifdef NTP 104 /* 105 * Generic NTP kernel interface 106 * 107 * These routines constitute the Network Time Protocol (NTP) interfaces 108 * for user and daemon application programs. The ntp_gettime() routine 109 * provides the time, maximum error (synch distance) and estimated error 110 * (dispersion) to client user application programs. The ntp_adjtime() 111 * routine is used by the NTP daemon to adjust the system clock to an 112 * externally derived time. The time offset and related variables set by 113 * this routine are used by other routines in this module to adjust the 114 * phase and frequency of the clock discipline loop which controls the 115 * system clock. 116 * 117 * When the kernel time is reckoned directly in nanoseconds (NTP_NANO 118 * defined), the time at each tick interrupt is derived directly from 119 * the kernel time variable. When the kernel time is reckoned in 120 * microseconds, (NTP_NANO undefined), the time is derived from the 121 * kernel time variable together with a variable representing the 122 * leftover nanoseconds at the last tick interrupt. In either case, the 123 * current nanosecond time is reckoned from these values plus an 124 * interpolated value derived by the clock routines in another 125 * architecture-specific module. The interpolation can use either a 126 * dedicated counter or a processor cycle counter (PCC) implemented in 127 * some architectures. 128 * 129 * Note that all routines must run at priority splclock or higher. 130 */ 131 /* 132 * Phase/frequency-lock loop (PLL/FLL) definitions 133 * 134 * The nanosecond clock discipline uses two variable types, time 135 * variables and frequency variables. Both types are represented as 64- 136 * bit fixed-point quantities with the decimal point between two 32-bit 137 * halves. On a 32-bit machine, each half is represented as a single 138 * word and mathematical operations are done using multiple-precision 139 * arithmetic. On a 64-bit machine, ordinary computer arithmetic is 140 * used. 141 * 142 * A time variable is a signed 64-bit fixed-point number in ns and 143 * fraction. It represents the remaining time offset to be amortized 144 * over succeeding tick interrupts. The maximum time offset is about 145 * 0.5 s and the resolution is about 2.3e-10 ns. 146 * 147 * 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 148 * 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 1 149 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 150 * |s s s| ns | 151 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 152 * | fraction | 153 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 154 * 155 * A frequency variable is a signed 64-bit fixed-point number in ns/s 156 * and fraction. It represents the ns and fraction to be added to the 157 * kernel time variable at each second. The maximum frequency offset is 158 * about +-500000 ns/s and the resolution is about 2.3e-10 ns/s. 159 * 160 * 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 161 * 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 1 162 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 163 * |s s s s s s s s s s s s s| ns/s | 164 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 165 * | fraction | 166 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 167 */ 168 /* 169 * The following variables establish the state of the PLL/FLL and the 170 * residual time and frequency offset of the local clock. 171 */ 172 #define SHIFT_PLL 4 /* PLL loop gain (shift) */ 173 #define SHIFT_FLL 2 /* FLL loop gain (shift) */ 174 175 static int time_state = TIME_OK; /* clock state */ 176 static int time_status = STA_UNSYNC; /* clock status bits */ 177 static long time_tai; /* TAI offset (s) */ 178 static long time_monitor; /* last time offset scaled (ns) */ 179 static long time_constant; /* poll interval (shift) (s) */ 180 static long time_precision = 1; /* clock precision (ns) */ 181 static long time_maxerror = MAXPHASE / 1000; /* maximum error (us) */ 182 static long time_esterror = MAXPHASE / 1000; /* estimated error (us) */ 183 static long time_reftime; /* time at last adjustment (s) */ 184 static l_fp time_offset; /* time offset (ns) */ 185 static l_fp time_freq; /* frequency offset (ns/s) */ 186 #endif /* NTP */ 187 188 static l_fp time_adj; /* tick adjust (ns/s) */ 189 int64_t time_adjtime; /* correction from adjtime(2) (usec) */ 190 191 extern int time_adjusted; /* ntp might have changed the system time */ 192 193 #ifdef NTP 194 #ifdef PPS_SYNC 195 /* 196 * The following variables are used when a pulse-per-second (PPS) signal 197 * is available and connected via a modem control lead. They establish 198 * the engineering parameters of the clock discipline loop when 199 * controlled by the PPS signal. 200 */ 201 #define PPS_FAVG 2 /* min freq avg interval (s) (shift) */ 202 #define PPS_FAVGDEF 8 /* default freq avg int (s) (shift) */ 203 #define PPS_FAVGMAX 15 /* max freq avg interval (s) (shift) */ 204 #define PPS_PAVG 4 /* phase avg interval (s) (shift) */ 205 #define PPS_VALID 120 /* PPS signal watchdog max (s) */ 206 #define PPS_MAXWANDER 100000 /* max PPS wander (ns/s) */ 207 #define PPS_POPCORN 2 /* popcorn spike threshold (shift) */ 208 209 static struct timespec pps_tf[3]; /* phase median filter */ 210 static l_fp pps_freq; /* scaled frequency offset (ns/s) */ 211 static long pps_fcount; /* frequency accumulator */ 212 static long pps_jitter; /* nominal jitter (ns) */ 213 static long pps_stabil; /* nominal stability (scaled ns/s) */ 214 static long pps_lastsec; /* time at last calibration (s) */ 215 static int pps_valid; /* signal watchdog counter */ 216 static int pps_shift = PPS_FAVG; /* interval duration (s) (shift) */ 217 static int pps_shiftmax = PPS_FAVGDEF; /* max interval duration (s) (shift) */ 218 static int pps_intcnt; /* wander counter */ 219 220 /* 221 * PPS signal quality monitors 222 */ 223 static long pps_calcnt; /* calibration intervals */ 224 static long pps_jitcnt; /* jitter limit exceeded */ 225 static long pps_stbcnt; /* stability limit exceeded */ 226 static long pps_errcnt; /* calibration errors */ 227 #endif /* PPS_SYNC */ 228 /* 229 * End of phase/frequency-lock loop (PLL/FLL) definitions 230 */ 231 232 static void hardupdate(long offset); 233 234 /* 235 * ntp_gettime() - NTP user application interface 236 */ 237 void 238 ntp_gettime(struct ntptimeval *ntv) 239 { 240 241 mutex_spin_enter(&timecounter_lock); 242 nanotime(&ntv->time); 243 ntv->maxerror = time_maxerror; 244 ntv->esterror = time_esterror; 245 ntv->tai = time_tai; 246 ntv->time_state = time_state; 247 mutex_spin_exit(&timecounter_lock); 248 } 249 250 /* ARGSUSED */ 251 /* 252 * ntp_adjtime() - NTP daemon application interface 253 */ 254 int 255 sys_ntp_adjtime(struct lwp *l, const struct sys_ntp_adjtime_args *uap, register_t *retval) 256 { 257 /* { 258 syscallarg(struct timex *) tp; 259 } */ 260 struct timex ntv; 261 int error = 0; 262 263 error = copyin((void *)SCARG(uap, tp), (void *)&ntv, sizeof(ntv)); 264 if (error != 0) 265 return (error); 266 267 if (ntv.modes != 0 && (error = kauth_authorize_system(l->l_cred, 268 KAUTH_SYSTEM_TIME, KAUTH_REQ_SYSTEM_TIME_NTPADJTIME, NULL, 269 NULL, NULL)) != 0) 270 return (error); 271 272 ntp_adjtime1(&ntv); 273 274 error = copyout((void *)&ntv, (void *)SCARG(uap, tp), sizeof(ntv)); 275 if (!error) 276 *retval = ntp_timestatus(); 277 278 return error; 279 } 280 281 void 282 ntp_adjtime1(struct timex *ntv) 283 { 284 long freq; 285 int modes; 286 287 /* 288 * Update selected clock variables - only the superuser can 289 * change anything. Note that there is no error checking here on 290 * the assumption the superuser should know what it is doing. 291 * Note that either the time constant or TAI offset are loaded 292 * from the ntv.constant member, depending on the mode bits. If 293 * the STA_PLL bit in the status word is cleared, the state and 294 * status words are reset to the initial values at boot. 295 */ 296 mutex_spin_enter(&timecounter_lock); 297 modes = ntv->modes; 298 if (modes != 0) 299 /* We need to save the system time during shutdown */ 300 time_adjusted |= 2; 301 if (modes & MOD_MAXERROR) 302 time_maxerror = ntv->maxerror; 303 if (modes & MOD_ESTERROR) 304 time_esterror = ntv->esterror; 305 if (modes & MOD_STATUS) { 306 if (time_status & STA_PLL && !(ntv->status & STA_PLL)) { 307 time_state = TIME_OK; 308 time_status = STA_UNSYNC; 309 #ifdef PPS_SYNC 310 pps_shift = PPS_FAVG; 311 #endif /* PPS_SYNC */ 312 } 313 time_status &= STA_RONLY; 314 time_status |= ntv->status & ~STA_RONLY; 315 } 316 if (modes & MOD_TIMECONST) { 317 if (ntv->constant < 0) 318 time_constant = 0; 319 else if (ntv->constant > MAXTC) 320 time_constant = MAXTC; 321 else 322 time_constant = ntv->constant; 323 } 324 if (modes & MOD_TAI) { 325 if (ntv->constant > 0) /* XXX zero & negative numbers ? */ 326 time_tai = ntv->constant; 327 } 328 #ifdef PPS_SYNC 329 if (modes & MOD_PPSMAX) { 330 if (ntv->shift < PPS_FAVG) 331 pps_shiftmax = PPS_FAVG; 332 else if (ntv->shift > PPS_FAVGMAX) 333 pps_shiftmax = PPS_FAVGMAX; 334 else 335 pps_shiftmax = ntv->shift; 336 } 337 #endif /* PPS_SYNC */ 338 if (modes & MOD_NANO) 339 time_status |= STA_NANO; 340 if (modes & MOD_MICRO) 341 time_status &= ~STA_NANO; 342 if (modes & MOD_CLKB) 343 time_status |= STA_CLK; 344 if (modes & MOD_CLKA) 345 time_status &= ~STA_CLK; 346 if (modes & MOD_FREQUENCY) { 347 freq = (ntv->freq * 1000LL) >> 16; 348 if (freq > MAXFREQ) 349 L_LINT(time_freq, MAXFREQ); 350 else if (freq < -MAXFREQ) 351 L_LINT(time_freq, -MAXFREQ); 352 else { 353 /* 354 * ntv.freq is [PPM * 2^16] = [us/s * 2^16] 355 * time_freq is [ns/s * 2^32] 356 */ 357 time_freq = ntv->freq * 1000LL * 65536LL; 358 } 359 #ifdef PPS_SYNC 360 pps_freq = time_freq; 361 #endif /* PPS_SYNC */ 362 } 363 if (modes & MOD_OFFSET) { 364 if (time_status & STA_NANO) 365 hardupdate(ntv->offset); 366 else 367 hardupdate(ntv->offset * 1000); 368 } 369 370 /* 371 * Retrieve all clock variables. Note that the TAI offset is 372 * returned only by ntp_gettime(); 373 */ 374 if (time_status & STA_NANO) 375 ntv->offset = L_GINT(time_offset); 376 else 377 ntv->offset = L_GINT(time_offset) / 1000; /* XXX rounding ? */ 378 ntv->freq = L_GINT((time_freq / 1000LL) << 16); 379 ntv->maxerror = time_maxerror; 380 ntv->esterror = time_esterror; 381 ntv->status = time_status; 382 ntv->constant = time_constant; 383 if (time_status & STA_NANO) 384 ntv->precision = time_precision; 385 else 386 ntv->precision = time_precision / 1000; 387 ntv->tolerance = MAXFREQ * SCALE_PPM; 388 #ifdef PPS_SYNC 389 ntv->shift = pps_shift; 390 ntv->ppsfreq = L_GINT((pps_freq / 1000LL) << 16); 391 if (time_status & STA_NANO) 392 ntv->jitter = pps_jitter; 393 else 394 ntv->jitter = pps_jitter / 1000; 395 ntv->stabil = pps_stabil; 396 ntv->calcnt = pps_calcnt; 397 ntv->errcnt = pps_errcnt; 398 ntv->jitcnt = pps_jitcnt; 399 ntv->stbcnt = pps_stbcnt; 400 #endif /* PPS_SYNC */ 401 mutex_spin_exit(&timecounter_lock); 402 } 403 #endif /* NTP */ 404 405 /* 406 * second_overflow() - called after ntp_tick_adjust() 407 * 408 * This routine is ordinarily called immediately following the above 409 * routine ntp_tick_adjust(). While these two routines are normally 410 * combined, they are separated here only for the purposes of 411 * simulation. 412 */ 413 void 414 ntp_update_second(int64_t *adjustment, time_t *newsec) 415 { 416 int tickrate; 417 l_fp ftemp; /* 32/64-bit temporary */ 418 419 KASSERT(mutex_owned(&timecounter_lock)); 420 421 #ifdef NTP 422 423 /* 424 * On rollover of the second both the nanosecond and microsecond 425 * clocks are updated and the state machine cranked as 426 * necessary. The phase adjustment to be used for the next 427 * second is calculated and the maximum error is increased by 428 * the tolerance. 429 */ 430 time_maxerror += MAXFREQ / 1000; 431 432 /* 433 * Leap second processing. If in leap-insert state at 434 * the end of the day, the system clock is set back one 435 * second; if in leap-delete state, the system clock is 436 * set ahead one second. The nano_time() routine or 437 * external clock driver will insure that reported time 438 * is always monotonic. 439 */ 440 switch (time_state) { 441 442 /* 443 * No warning. 444 */ 445 case TIME_OK: 446 if (time_status & STA_INS) 447 time_state = TIME_INS; 448 else if (time_status & STA_DEL) 449 time_state = TIME_DEL; 450 break; 451 452 /* 453 * Insert second 23:59:60 following second 454 * 23:59:59. 455 */ 456 case TIME_INS: 457 if (!(time_status & STA_INS)) 458 time_state = TIME_OK; 459 else if ((*newsec) % 86400 == 0) { 460 (*newsec)--; 461 time_state = TIME_OOP; 462 time_tai++; 463 } 464 break; 465 466 /* 467 * Delete second 23:59:59. 468 */ 469 case TIME_DEL: 470 if (!(time_status & STA_DEL)) 471 time_state = TIME_OK; 472 else if (((*newsec) + 1) % 86400 == 0) { 473 (*newsec)++; 474 time_tai--; 475 time_state = TIME_WAIT; 476 } 477 break; 478 479 /* 480 * Insert second in progress. 481 */ 482 case TIME_OOP: 483 time_state = TIME_WAIT; 484 break; 485 486 /* 487 * Wait for status bits to clear. 488 */ 489 case TIME_WAIT: 490 if (!(time_status & (STA_INS | STA_DEL))) 491 time_state = TIME_OK; 492 } 493 494 /* 495 * Compute the total time adjustment for the next second 496 * in ns. The offset is reduced by a factor depending on 497 * whether the PPS signal is operating. Note that the 498 * value is in effect scaled by the clock frequency, 499 * since the adjustment is added at each tick interrupt. 500 */ 501 ftemp = time_offset; 502 #ifdef PPS_SYNC 503 /* XXX even if PPS signal dies we should finish adjustment ? */ 504 if (time_status & STA_PPSTIME && time_status & 505 STA_PPSSIGNAL) 506 L_RSHIFT(ftemp, pps_shift); 507 else 508 L_RSHIFT(ftemp, SHIFT_PLL + time_constant); 509 #else 510 L_RSHIFT(ftemp, SHIFT_PLL + time_constant); 511 #endif /* PPS_SYNC */ 512 time_adj = ftemp; 513 L_SUB(time_offset, ftemp); 514 L_ADD(time_adj, time_freq); 515 516 #ifdef PPS_SYNC 517 if (pps_valid > 0) 518 pps_valid--; 519 else 520 time_status &= ~STA_PPSSIGNAL; 521 #endif /* PPS_SYNC */ 522 #else /* !NTP */ 523 L_CLR(time_adj); 524 #endif /* !NTP */ 525 526 /* 527 * Apply any correction from adjtime(2). If more than one second 528 * off we slew at a rate of 5ms/s (5000 PPM) else 500us/s (500PPM) 529 * until the last second is slewed the final < 500 usecs. 530 */ 531 if (time_adjtime != 0) { 532 if (time_adjtime > 1000000) 533 tickrate = 5000; 534 else if (time_adjtime < -1000000) 535 tickrate = -5000; 536 else if (time_adjtime > 500) 537 tickrate = 500; 538 else if (time_adjtime < -500) 539 tickrate = -500; 540 else 541 tickrate = time_adjtime; 542 time_adjtime -= tickrate; 543 L_LINT(ftemp, tickrate * 1000); 544 L_ADD(time_adj, ftemp); 545 } 546 *adjustment = time_adj; 547 } 548 549 /* 550 * ntp_init() - initialize variables and structures 551 * 552 * This routine must be called after the kernel variables hz and tick 553 * are set or changed and before the next tick interrupt. In this 554 * particular implementation, these values are assumed set elsewhere in 555 * the kernel. The design allows the clock frequency and tick interval 556 * to be changed while the system is running. So, this routine should 557 * probably be integrated with the code that does that. 558 */ 559 void 560 ntp_init(void) 561 { 562 563 /* 564 * The following variables are initialized only at startup. Only 565 * those structures not cleared by the compiler need to be 566 * initialized, and these only in the simulator. In the actual 567 * kernel, any nonzero values here will quickly evaporate. 568 */ 569 L_CLR(time_adj); 570 #ifdef NTP 571 L_CLR(time_offset); 572 L_CLR(time_freq); 573 #ifdef PPS_SYNC 574 pps_tf[0].tv_sec = pps_tf[0].tv_nsec = 0; 575 pps_tf[1].tv_sec = pps_tf[1].tv_nsec = 0; 576 pps_tf[2].tv_sec = pps_tf[2].tv_nsec = 0; 577 pps_fcount = 0; 578 L_CLR(pps_freq); 579 #endif /* PPS_SYNC */ 580 #endif 581 } 582 583 #ifdef NTP 584 /* 585 * hardupdate() - local clock update 586 * 587 * This routine is called by ntp_adjtime() to update the local clock 588 * phase and frequency. The implementation is of an adaptive-parameter, 589 * hybrid phase/frequency-lock loop (PLL/FLL). The routine computes new 590 * time and frequency offset estimates for each call. If the kernel PPS 591 * discipline code is configured (PPS_SYNC), the PPS signal itself 592 * determines the new time offset, instead of the calling argument. 593 * Presumably, calls to ntp_adjtime() occur only when the caller 594 * believes the local clock is valid within some bound (+-128 ms with 595 * NTP). If the caller's time is far different than the PPS time, an 596 * argument will ensue, and it's not clear who will lose. 597 * 598 * For uncompensated quartz crystal oscillators and nominal update 599 * intervals less than 256 s, operation should be in phase-lock mode, 600 * where the loop is disciplined to phase. For update intervals greater 601 * than 1024 s, operation should be in frequency-lock mode, where the 602 * loop is disciplined to frequency. Between 256 s and 1024 s, the mode 603 * is selected by the STA_MODE status bit. 604 * 605 * Note: splclock() is in effect. 606 */ 607 void 608 hardupdate(long offset) 609 { 610 long mtemp; 611 l_fp ftemp; 612 613 KASSERT(mutex_owned(&timecounter_lock)); 614 615 /* 616 * Select how the phase is to be controlled and from which 617 * source. If the PPS signal is present and enabled to 618 * discipline the time, the PPS offset is used; otherwise, the 619 * argument offset is used. 620 */ 621 if (!(time_status & STA_PLL)) 622 return; 623 if (!(time_status & STA_PPSTIME && time_status & 624 STA_PPSSIGNAL)) { 625 if (offset > MAXPHASE) 626 time_monitor = MAXPHASE; 627 else if (offset < -MAXPHASE) 628 time_monitor = -MAXPHASE; 629 else 630 time_monitor = offset; 631 L_LINT(time_offset, time_monitor); 632 } 633 634 /* 635 * Select how the frequency is to be controlled and in which 636 * mode (PLL or FLL). If the PPS signal is present and enabled 637 * to discipline the frequency, the PPS frequency is used; 638 * otherwise, the argument offset is used to compute it. 639 */ 640 if (time_status & STA_PPSFREQ && time_status & STA_PPSSIGNAL) { 641 time_reftime = time_second; 642 return; 643 } 644 if (time_status & STA_FREQHOLD || time_reftime == 0) 645 time_reftime = time_second; 646 mtemp = time_second - time_reftime; 647 L_LINT(ftemp, time_monitor); 648 L_RSHIFT(ftemp, (SHIFT_PLL + 2 + time_constant) << 1); 649 L_MPY(ftemp, mtemp); 650 L_ADD(time_freq, ftemp); 651 time_status &= ~STA_MODE; 652 if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > 653 MAXSEC)) { 654 L_LINT(ftemp, (time_monitor << 4) / mtemp); 655 L_RSHIFT(ftemp, SHIFT_FLL + 4); 656 L_ADD(time_freq, ftemp); 657 time_status |= STA_MODE; 658 } 659 time_reftime = time_second; 660 if (L_GINT(time_freq) > MAXFREQ) 661 L_LINT(time_freq, MAXFREQ); 662 else if (L_GINT(time_freq) < -MAXFREQ) 663 L_LINT(time_freq, -MAXFREQ); 664 } 665 666 #ifdef PPS_SYNC 667 /* 668 * hardpps() - discipline CPU clock oscillator to external PPS signal 669 * 670 * This routine is called at each PPS interrupt in order to discipline 671 * the CPU clock oscillator to the PPS signal. It measures the PPS phase 672 * and leaves it in a handy spot for the hardclock() routine. It 673 * integrates successive PPS phase differences and calculates the 674 * frequency offset. This is used in hardclock() to discipline the CPU 675 * clock oscillator so that intrinsic frequency error is cancelled out. 676 * The code requires the caller to capture the time and hardware counter 677 * value at the on-time PPS signal transition. 678 * 679 * Note that, on some Unix systems, this routine runs at an interrupt 680 * priority level higher than the timer interrupt routine hardclock(). 681 * Therefore, the variables used are distinct from the hardclock() 682 * variables, except for certain exceptions: The PPS frequency pps_freq 683 * and phase pps_offset variables are determined by this routine and 684 * updated atomically. The time_tolerance variable can be considered a 685 * constant, since it is infrequently changed, and then only when the 686 * PPS signal is disabled. The watchdog counter pps_valid is updated 687 * once per second by hardclock() and is atomically cleared in this 688 * routine. 689 */ 690 void 691 hardpps(struct timespec *tsp, /* time at PPS */ 692 long nsec /* hardware counter at PPS */) 693 { 694 long u_sec, u_nsec, v_nsec; /* temps */ 695 l_fp ftemp; 696 697 KASSERT(mutex_owned(&timecounter_lock)); 698 699 /* 700 * The signal is first processed by a range gate and frequency 701 * discriminator. The range gate rejects noise spikes outside 702 * the range +-500 us. The frequency discriminator rejects input 703 * signals with apparent frequency outside the range 1 +-500 704 * PPM. If two hits occur in the same second, we ignore the 705 * later hit; if not and a hit occurs outside the range gate, 706 * keep the later hit for later comparison, but do not process 707 * it. 708 */ 709 time_status |= STA_PPSSIGNAL | STA_PPSJITTER; 710 time_status &= ~(STA_PPSWANDER | STA_PPSERROR); 711 pps_valid = PPS_VALID; 712 u_sec = tsp->tv_sec; 713 u_nsec = tsp->tv_nsec; 714 if (u_nsec >= (NANOSECOND >> 1)) { 715 u_nsec -= NANOSECOND; 716 u_sec++; 717 } 718 v_nsec = u_nsec - pps_tf[0].tv_nsec; 719 if (u_sec == pps_tf[0].tv_sec && v_nsec < NANOSECOND - 720 MAXFREQ) 721 return; 722 pps_tf[2] = pps_tf[1]; 723 pps_tf[1] = pps_tf[0]; 724 pps_tf[0].tv_sec = u_sec; 725 pps_tf[0].tv_nsec = u_nsec; 726 727 /* 728 * Compute the difference between the current and previous 729 * counter values. If the difference exceeds 0.5 s, assume it 730 * has wrapped around, so correct 1.0 s. If the result exceeds 731 * the tick interval, the sample point has crossed a tick 732 * boundary during the last second, so correct the tick. Very 733 * intricate. 734 */ 735 u_nsec = nsec; 736 if (u_nsec > (NANOSECOND >> 1)) 737 u_nsec -= NANOSECOND; 738 else if (u_nsec < -(NANOSECOND >> 1)) 739 u_nsec += NANOSECOND; 740 pps_fcount += u_nsec; 741 if (v_nsec > MAXFREQ || v_nsec < -MAXFREQ) 742 return; 743 time_status &= ~STA_PPSJITTER; 744 745 /* 746 * A three-stage median filter is used to help denoise the PPS 747 * time. The median sample becomes the time offset estimate; the 748 * difference between the other two samples becomes the time 749 * dispersion (jitter) estimate. 750 */ 751 if (pps_tf[0].tv_nsec > pps_tf[1].tv_nsec) { 752 if (pps_tf[1].tv_nsec > pps_tf[2].tv_nsec) { 753 v_nsec = pps_tf[1].tv_nsec; /* 0 1 2 */ 754 u_nsec = pps_tf[0].tv_nsec - pps_tf[2].tv_nsec; 755 } else if (pps_tf[2].tv_nsec > pps_tf[0].tv_nsec) { 756 v_nsec = pps_tf[0].tv_nsec; /* 2 0 1 */ 757 u_nsec = pps_tf[2].tv_nsec - pps_tf[1].tv_nsec; 758 } else { 759 v_nsec = pps_tf[2].tv_nsec; /* 0 2 1 */ 760 u_nsec = pps_tf[0].tv_nsec - pps_tf[1].tv_nsec; 761 } 762 } else { 763 if (pps_tf[1].tv_nsec < pps_tf[2].tv_nsec) { 764 v_nsec = pps_tf[1].tv_nsec; /* 2 1 0 */ 765 u_nsec = pps_tf[2].tv_nsec - pps_tf[0].tv_nsec; 766 } else if (pps_tf[2].tv_nsec < pps_tf[0].tv_nsec) { 767 v_nsec = pps_tf[0].tv_nsec; /* 1 0 2 */ 768 u_nsec = pps_tf[1].tv_nsec - pps_tf[2].tv_nsec; 769 } else { 770 v_nsec = pps_tf[2].tv_nsec; /* 1 2 0 */ 771 u_nsec = pps_tf[1].tv_nsec - pps_tf[0].tv_nsec; 772 } 773 } 774 775 /* 776 * Nominal jitter is due to PPS signal noise and interrupt 777 * latency. If it exceeds the popcorn threshold, the sample is 778 * discarded. otherwise, if so enabled, the time offset is 779 * updated. We can tolerate a modest loss of data here without 780 * much degrading time accuracy. 781 */ 782 if (u_nsec > (pps_jitter << PPS_POPCORN)) { 783 time_status |= STA_PPSJITTER; 784 pps_jitcnt++; 785 } else if (time_status & STA_PPSTIME) { 786 time_monitor = -v_nsec; 787 L_LINT(time_offset, time_monitor); 788 } 789 pps_jitter += (u_nsec - pps_jitter) >> PPS_FAVG; 790 u_sec = pps_tf[0].tv_sec - pps_lastsec; 791 if (u_sec < (1 << pps_shift)) 792 return; 793 794 /* 795 * At the end of the calibration interval the difference between 796 * the first and last counter values becomes the scaled 797 * frequency. It will later be divided by the length of the 798 * interval to determine the frequency update. If the frequency 799 * exceeds a sanity threshold, or if the actual calibration 800 * interval is not equal to the expected length, the data are 801 * discarded. We can tolerate a modest loss of data here without 802 * much degrading frequency accuracy. 803 */ 804 pps_calcnt++; 805 v_nsec = -pps_fcount; 806 pps_lastsec = pps_tf[0].tv_sec; 807 pps_fcount = 0; 808 u_nsec = MAXFREQ << pps_shift; 809 if (v_nsec > u_nsec || v_nsec < -u_nsec || u_sec != (1 << 810 pps_shift)) { 811 time_status |= STA_PPSERROR; 812 pps_errcnt++; 813 return; 814 } 815 816 /* 817 * Here the raw frequency offset and wander (stability) is 818 * calculated. If the wander is less than the wander threshold 819 * for four consecutive averaging intervals, the interval is 820 * doubled; if it is greater than the threshold for four 821 * consecutive intervals, the interval is halved. The scaled 822 * frequency offset is converted to frequency offset. The 823 * stability metric is calculated as the average of recent 824 * frequency changes, but is used only for performance 825 * monitoring. 826 */ 827 L_LINT(ftemp, v_nsec); 828 L_RSHIFT(ftemp, pps_shift); 829 L_SUB(ftemp, pps_freq); 830 u_nsec = L_GINT(ftemp); 831 if (u_nsec > PPS_MAXWANDER) { 832 L_LINT(ftemp, PPS_MAXWANDER); 833 pps_intcnt--; 834 time_status |= STA_PPSWANDER; 835 pps_stbcnt++; 836 } else if (u_nsec < -PPS_MAXWANDER) { 837 L_LINT(ftemp, -PPS_MAXWANDER); 838 pps_intcnt--; 839 time_status |= STA_PPSWANDER; 840 pps_stbcnt++; 841 } else { 842 pps_intcnt++; 843 } 844 if (pps_intcnt >= 4) { 845 pps_intcnt = 4; 846 if (pps_shift < pps_shiftmax) { 847 pps_shift++; 848 pps_intcnt = 0; 849 } 850 } else if (pps_intcnt <= -4 || pps_shift > pps_shiftmax) { 851 pps_intcnt = -4; 852 if (pps_shift > PPS_FAVG) { 853 pps_shift--; 854 pps_intcnt = 0; 855 } 856 } 857 if (u_nsec < 0) 858 u_nsec = -u_nsec; 859 pps_stabil += (u_nsec * SCALE_PPM - pps_stabil) >> PPS_FAVG; 860 861 /* 862 * The PPS frequency is recalculated and clamped to the maximum 863 * MAXFREQ. If enabled, the system clock frequency is updated as 864 * well. 865 */ 866 L_ADD(pps_freq, ftemp); 867 u_nsec = L_GINT(pps_freq); 868 if (u_nsec > MAXFREQ) 869 L_LINT(pps_freq, MAXFREQ); 870 else if (u_nsec < -MAXFREQ) 871 L_LINT(pps_freq, -MAXFREQ); 872 if (time_status & STA_PPSFREQ) 873 time_freq = pps_freq; 874 } 875 #endif /* PPS_SYNC */ 876 #endif /* NTP */ 877 878 #ifdef NTP 879 int 880 ntp_timestatus(void) 881 { 882 int rv; 883 884 /* 885 * Status word error decode. If any of these conditions 886 * occur, an error is returned, instead of the status 887 * word. Most applications will care only about the fact 888 * the system clock may not be trusted, not about the 889 * details. 890 * 891 * Hardware or software error 892 */ 893 mutex_spin_enter(&timecounter_lock); 894 if ((time_status & (STA_UNSYNC | STA_CLOCKERR)) || 895 896 /* 897 * PPS signal lost when either time or frequency 898 * synchronization requested 899 */ 900 (time_status & (STA_PPSFREQ | STA_PPSTIME) && 901 !(time_status & STA_PPSSIGNAL)) || 902 903 /* 904 * PPS jitter exceeded when time synchronization 905 * requested 906 */ 907 (time_status & STA_PPSTIME && 908 time_status & STA_PPSJITTER) || 909 910 /* 911 * PPS wander exceeded or calibration error when 912 * frequency synchronization requested 913 */ 914 (time_status & STA_PPSFREQ && 915 time_status & (STA_PPSWANDER | STA_PPSERROR))) 916 rv = TIME_ERROR; 917 else 918 rv = time_state; 919 mutex_spin_exit(&timecounter_lock); 920 921 return rv; 922 } 923 924 /*ARGSUSED*/ 925 /* 926 * ntp_gettime() - NTP user application interface 927 */ 928 int 929 sys___ntp_gettime50(struct lwp *l, const struct sys___ntp_gettime50_args *uap, register_t *retval) 930 { 931 /* { 932 syscallarg(struct ntptimeval *) ntvp; 933 } */ 934 struct ntptimeval ntv; 935 int error = 0; 936 937 if (SCARG(uap, ntvp)) { 938 ntp_gettime(&ntv); 939 940 error = copyout((void *)&ntv, (void *)SCARG(uap, ntvp), 941 sizeof(ntv)); 942 } 943 if (!error) { 944 *retval = ntp_timestatus(); 945 } 946 return(error); 947 } 948 949 /* 950 * return information about kernel precision timekeeping 951 */ 952 static int 953 sysctl_kern_ntptime(SYSCTLFN_ARGS) 954 { 955 struct sysctlnode node; 956 struct ntptimeval ntv; 957 958 ntp_gettime(&ntv); 959 960 node = *rnode; 961 node.sysctl_data = &ntv; 962 node.sysctl_size = sizeof(ntv); 963 return (sysctl_lookup(SYSCTLFN_CALL(&node))); 964 } 965 966 SYSCTL_SETUP(sysctl_kern_ntptime_setup, "sysctl kern.ntptime node setup") 967 { 968 969 sysctl_createv(clog, 0, NULL, NULL, 970 CTLFLAG_PERMANENT, 971 CTLTYPE_NODE, "kern", NULL, 972 NULL, 0, NULL, 0, 973 CTL_KERN, CTL_EOL); 974 975 sysctl_createv(clog, 0, NULL, NULL, 976 CTLFLAG_PERMANENT, 977 CTLTYPE_STRUCT, "ntptime", 978 SYSCTL_DESCR("Kernel clock values for NTP"), 979 sysctl_kern_ntptime, 0, NULL, 980 sizeof(struct ntptimeval), 981 CTL_KERN, KERN_NTPTIME, CTL_EOL); 982 } 983 #else /* !NTP */ 984 /* For some reason, raising SIGSYS (as sys_nosys would) is problematic. */ 985 986 int 987 sys___ntp_gettime50(struct lwp *l, const struct sys___ntp_gettime50_args *uap, register_t *retval) 988 { 989 990 return(ENOSYS); 991 } 992 993 #endif /* !NTP */ 994