1 /*- 2 * ---------------------------------------------------------------------------- 3 * "THE BEER-WARE LICENSE" (Revision 42): 4 * <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you 5 * can do whatever you want with this stuff. If we meet some day, and you think 6 * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp 7 * ---------------------------------------------------------------------------- 8 */ 9 10 #include <sys/cdefs.h> 11 __FBSDID("$FreeBSD$"); 12 13 #include "opt_ntp.h" 14 15 #include <sys/param.h> 16 #include <sys/kernel.h> 17 #include <sys/sysctl.h> 18 #include <sys/syslog.h> 19 #include <sys/systm.h> 20 #include <sys/timepps.h> 21 #include <sys/timetc.h> 22 #include <sys/timex.h> 23 24 /* 25 * A large step happens on boot. This constant detects such steps. 26 * It is relatively small so that ntp_update_second gets called enough 27 * in the typical 'missed a couple of seconds' case, but doesn't loop 28 * forever when the time step is large. 29 */ 30 #define LARGE_STEP 200 31 32 /* 33 * Implement a dummy timecounter which we can use until we get a real one 34 * in the air. This allows the console and other early stuff to use 35 * time services. 36 */ 37 38 static u_int 39 dummy_get_timecount(struct timecounter *tc) 40 { 41 static u_int now; 42 43 return (++now); 44 } 45 46 static struct timecounter dummy_timecounter = { 47 dummy_get_timecount, 0, ~0u, 1000000, "dummy", -1000000 48 }; 49 50 struct timehands { 51 /* These fields must be initialized by the driver. */ 52 struct timecounter *th_counter; 53 int64_t th_adjustment; 54 uint64_t th_scale; 55 u_int th_offset_count; 56 struct bintime th_offset; 57 struct timeval th_microtime; 58 struct timespec th_nanotime; 59 /* Fields not to be copied in tc_windup start with th_generation. */ 60 volatile u_int th_generation; 61 struct timehands *th_next; 62 }; 63 64 static struct timehands th0; 65 static struct timehands th9 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th0}; 66 static struct timehands th8 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th9}; 67 static struct timehands th7 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th8}; 68 static struct timehands th6 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th7}; 69 static struct timehands th5 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th6}; 70 static struct timehands th4 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th5}; 71 static struct timehands th3 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th4}; 72 static struct timehands th2 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th3}; 73 static struct timehands th1 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th2}; 74 static struct timehands th0 = { 75 &dummy_timecounter, 76 0, 77 (uint64_t)-1 / 1000000, 78 0, 79 {1, 0}, 80 {0, 0}, 81 {0, 0}, 82 1, 83 &th1 84 }; 85 86 static struct timehands *volatile timehands = &th0; 87 struct timecounter *timecounter = &dummy_timecounter; 88 static struct timecounter *timecounters = &dummy_timecounter; 89 90 int tc_min_ticktock_freq = 1; 91 92 time_t time_second = 1; 93 time_t time_uptime = 1; 94 95 struct bintime boottimebin; 96 struct timeval boottime; 97 static int sysctl_kern_boottime(SYSCTL_HANDLER_ARGS); 98 SYSCTL_PROC(_kern, KERN_BOOTTIME, boottime, CTLTYPE_STRUCT|CTLFLAG_RD, 99 NULL, 0, sysctl_kern_boottime, "S,timeval", "System boottime"); 100 101 SYSCTL_NODE(_kern, OID_AUTO, timecounter, CTLFLAG_RW, 0, ""); 102 SYSCTL_NODE(_kern_timecounter, OID_AUTO, tc, CTLFLAG_RW, 0, ""); 103 104 static int timestepwarnings; 105 SYSCTL_INT(_kern_timecounter, OID_AUTO, stepwarnings, CTLFLAG_RW, 106 ×tepwarnings, 0, "Log time steps"); 107 108 static void tc_windup(void); 109 static void cpu_tick_calibrate(int); 110 111 static int 112 sysctl_kern_boottime(SYSCTL_HANDLER_ARGS) 113 { 114 #ifdef SCTL_MASK32 115 int tv[2]; 116 117 if (req->flags & SCTL_MASK32) { 118 tv[0] = boottime.tv_sec; 119 tv[1] = boottime.tv_usec; 120 return SYSCTL_OUT(req, tv, sizeof(tv)); 121 } else 122 #endif 123 return SYSCTL_OUT(req, &boottime, sizeof(boottime)); 124 } 125 126 static int 127 sysctl_kern_timecounter_get(SYSCTL_HANDLER_ARGS) 128 { 129 u_int ncount; 130 struct timecounter *tc = arg1; 131 132 ncount = tc->tc_get_timecount(tc); 133 return sysctl_handle_int(oidp, &ncount, 0, req); 134 } 135 136 static int 137 sysctl_kern_timecounter_freq(SYSCTL_HANDLER_ARGS) 138 { 139 uint64_t freq; 140 struct timecounter *tc = arg1; 141 142 freq = tc->tc_frequency; 143 return sysctl_handle_64(oidp, &freq, 0, req); 144 } 145 146 /* 147 * Return the difference between the timehands' counter value now and what 148 * was when we copied it to the timehands' offset_count. 149 */ 150 static __inline u_int 151 tc_delta(struct timehands *th) 152 { 153 struct timecounter *tc; 154 155 tc = th->th_counter; 156 return ((tc->tc_get_timecount(tc) - th->th_offset_count) & 157 tc->tc_counter_mask); 158 } 159 160 /* 161 * Functions for reading the time. We have to loop until we are sure that 162 * the timehands that we operated on was not updated under our feet. See 163 * the comment in <sys/time.h> for a description of these 12 functions. 164 */ 165 166 void 167 binuptime(struct bintime *bt) 168 { 169 struct timehands *th; 170 u_int gen; 171 172 do { 173 th = timehands; 174 gen = th->th_generation; 175 *bt = th->th_offset; 176 bintime_addx(bt, th->th_scale * tc_delta(th)); 177 } while (gen == 0 || gen != th->th_generation); 178 } 179 180 void 181 nanouptime(struct timespec *tsp) 182 { 183 struct bintime bt; 184 185 binuptime(&bt); 186 bintime2timespec(&bt, tsp); 187 } 188 189 void 190 microuptime(struct timeval *tvp) 191 { 192 struct bintime bt; 193 194 binuptime(&bt); 195 bintime2timeval(&bt, tvp); 196 } 197 198 void 199 bintime(struct bintime *bt) 200 { 201 202 binuptime(bt); 203 bintime_add(bt, &boottimebin); 204 } 205 206 void 207 nanotime(struct timespec *tsp) 208 { 209 struct bintime bt; 210 211 bintime(&bt); 212 bintime2timespec(&bt, tsp); 213 } 214 215 void 216 microtime(struct timeval *tvp) 217 { 218 struct bintime bt; 219 220 bintime(&bt); 221 bintime2timeval(&bt, tvp); 222 } 223 224 void 225 getbinuptime(struct bintime *bt) 226 { 227 struct timehands *th; 228 u_int gen; 229 230 do { 231 th = timehands; 232 gen = th->th_generation; 233 *bt = th->th_offset; 234 } while (gen == 0 || gen != th->th_generation); 235 } 236 237 void 238 getnanouptime(struct timespec *tsp) 239 { 240 struct timehands *th; 241 u_int gen; 242 243 do { 244 th = timehands; 245 gen = th->th_generation; 246 bintime2timespec(&th->th_offset, tsp); 247 } while (gen == 0 || gen != th->th_generation); 248 } 249 250 void 251 getmicrouptime(struct timeval *tvp) 252 { 253 struct timehands *th; 254 u_int gen; 255 256 do { 257 th = timehands; 258 gen = th->th_generation; 259 bintime2timeval(&th->th_offset, tvp); 260 } while (gen == 0 || gen != th->th_generation); 261 } 262 263 void 264 getbintime(struct bintime *bt) 265 { 266 struct timehands *th; 267 u_int gen; 268 269 do { 270 th = timehands; 271 gen = th->th_generation; 272 *bt = th->th_offset; 273 } while (gen == 0 || gen != th->th_generation); 274 bintime_add(bt, &boottimebin); 275 } 276 277 void 278 getnanotime(struct timespec *tsp) 279 { 280 struct timehands *th; 281 u_int gen; 282 283 do { 284 th = timehands; 285 gen = th->th_generation; 286 *tsp = th->th_nanotime; 287 } while (gen == 0 || gen != th->th_generation); 288 } 289 290 void 291 getmicrotime(struct timeval *tvp) 292 { 293 struct timehands *th; 294 u_int gen; 295 296 do { 297 th = timehands; 298 gen = th->th_generation; 299 *tvp = th->th_microtime; 300 } while (gen == 0 || gen != th->th_generation); 301 } 302 303 /* 304 * Initialize a new timecounter and possibly use it. 305 */ 306 void 307 tc_init(struct timecounter *tc) 308 { 309 u_int u; 310 struct sysctl_oid *tc_root; 311 312 u = tc->tc_frequency / tc->tc_counter_mask; 313 /* XXX: We need some margin here, 10% is a guess */ 314 u *= 11; 315 u /= 10; 316 if (u > hz && tc->tc_quality >= 0) { 317 tc->tc_quality = -2000; 318 if (bootverbose) { 319 printf("Timecounter \"%s\" frequency %ju Hz", 320 tc->tc_name, (uintmax_t)tc->tc_frequency); 321 printf(" -- Insufficient hz, needs at least %u\n", u); 322 } 323 } else if (tc->tc_quality >= 0 || bootverbose) { 324 printf("Timecounter \"%s\" frequency %ju Hz quality %d\n", 325 tc->tc_name, (uintmax_t)tc->tc_frequency, 326 tc->tc_quality); 327 } 328 329 tc->tc_next = timecounters; 330 timecounters = tc; 331 /* 332 * Set up sysctl tree for this counter. 333 */ 334 tc_root = SYSCTL_ADD_NODE(NULL, 335 SYSCTL_STATIC_CHILDREN(_kern_timecounter_tc), OID_AUTO, tc->tc_name, 336 CTLFLAG_RW, 0, "timecounter description"); 337 SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO, 338 "mask", CTLFLAG_RD, &(tc->tc_counter_mask), 0, 339 "mask for implemented bits"); 340 SYSCTL_ADD_PROC(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO, 341 "counter", CTLTYPE_UINT | CTLFLAG_RD, tc, sizeof(*tc), 342 sysctl_kern_timecounter_get, "IU", "current timecounter value"); 343 SYSCTL_ADD_PROC(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO, 344 "frequency", CTLTYPE_U64 | CTLFLAG_RD, tc, sizeof(*tc), 345 sysctl_kern_timecounter_freq, "QU", "timecounter frequency"); 346 SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO, 347 "quality", CTLFLAG_RD, &(tc->tc_quality), 0, 348 "goodness of time counter"); 349 /* 350 * Never automatically use a timecounter with negative quality. 351 * Even though we run on the dummy counter, switching here may be 352 * worse since this timecounter may not be monotonous. 353 */ 354 if (tc->tc_quality < 0) 355 return; 356 if (tc->tc_quality < timecounter->tc_quality) 357 return; 358 if (tc->tc_quality == timecounter->tc_quality && 359 tc->tc_frequency < timecounter->tc_frequency) 360 return; 361 (void)tc->tc_get_timecount(tc); 362 (void)tc->tc_get_timecount(tc); 363 timecounter = tc; 364 } 365 366 /* Report the frequency of the current timecounter. */ 367 uint64_t 368 tc_getfrequency(void) 369 { 370 371 return (timehands->th_counter->tc_frequency); 372 } 373 374 /* 375 * Step our concept of UTC. This is done by modifying our estimate of 376 * when we booted. 377 * XXX: not locked. 378 */ 379 void 380 tc_setclock(struct timespec *ts) 381 { 382 struct timespec tbef, taft; 383 struct bintime bt, bt2; 384 385 cpu_tick_calibrate(1); 386 nanotime(&tbef); 387 timespec2bintime(ts, &bt); 388 binuptime(&bt2); 389 bintime_sub(&bt, &bt2); 390 bintime_add(&bt2, &boottimebin); 391 boottimebin = bt; 392 bintime2timeval(&bt, &boottime); 393 394 /* XXX fiddle all the little crinkly bits around the fiords... */ 395 tc_windup(); 396 nanotime(&taft); 397 if (timestepwarnings) { 398 log(LOG_INFO, 399 "Time stepped from %jd.%09ld to %jd.%09ld (%jd.%09ld)\n", 400 (intmax_t)tbef.tv_sec, tbef.tv_nsec, 401 (intmax_t)taft.tv_sec, taft.tv_nsec, 402 (intmax_t)ts->tv_sec, ts->tv_nsec); 403 } 404 cpu_tick_calibrate(1); 405 } 406 407 /* 408 * Initialize the next struct timehands in the ring and make 409 * it the active timehands. Along the way we might switch to a different 410 * timecounter and/or do seconds processing in NTP. Slightly magic. 411 */ 412 static void 413 tc_windup(void) 414 { 415 struct bintime bt; 416 struct timehands *th, *tho; 417 uint64_t scale; 418 u_int delta, ncount, ogen; 419 int i; 420 time_t t; 421 422 /* 423 * Make the next timehands a copy of the current one, but do not 424 * overwrite the generation or next pointer. While we update 425 * the contents, the generation must be zero. 426 */ 427 tho = timehands; 428 th = tho->th_next; 429 ogen = th->th_generation; 430 th->th_generation = 0; 431 bcopy(tho, th, offsetof(struct timehands, th_generation)); 432 433 /* 434 * Capture a timecounter delta on the current timecounter and if 435 * changing timecounters, a counter value from the new timecounter. 436 * Update the offset fields accordingly. 437 */ 438 delta = tc_delta(th); 439 if (th->th_counter != timecounter) 440 ncount = timecounter->tc_get_timecount(timecounter); 441 else 442 ncount = 0; 443 th->th_offset_count += delta; 444 th->th_offset_count &= th->th_counter->tc_counter_mask; 445 while (delta > th->th_counter->tc_frequency) { 446 /* Eat complete unadjusted seconds. */ 447 delta -= th->th_counter->tc_frequency; 448 th->th_offset.sec++; 449 } 450 if ((delta > th->th_counter->tc_frequency / 2) && 451 (th->th_scale * delta < ((uint64_t)1 << 63))) { 452 /* The product th_scale * delta just barely overflows. */ 453 th->th_offset.sec++; 454 } 455 bintime_addx(&th->th_offset, th->th_scale * delta); 456 457 /* 458 * Hardware latching timecounters may not generate interrupts on 459 * PPS events, so instead we poll them. There is a finite risk that 460 * the hardware might capture a count which is later than the one we 461 * got above, and therefore possibly in the next NTP second which might 462 * have a different rate than the current NTP second. It doesn't 463 * matter in practice. 464 */ 465 if (tho->th_counter->tc_poll_pps) 466 tho->th_counter->tc_poll_pps(tho->th_counter); 467 468 /* 469 * Deal with NTP second processing. The for loop normally 470 * iterates at most once, but in extreme situations it might 471 * keep NTP sane if timeouts are not run for several seconds. 472 * At boot, the time step can be large when the TOD hardware 473 * has been read, so on really large steps, we call 474 * ntp_update_second only twice. We need to call it twice in 475 * case we missed a leap second. 476 */ 477 bt = th->th_offset; 478 bintime_add(&bt, &boottimebin); 479 i = bt.sec - tho->th_microtime.tv_sec; 480 if (i > LARGE_STEP) 481 i = 2; 482 for (; i > 0; i--) { 483 t = bt.sec; 484 ntp_update_second(&th->th_adjustment, &bt.sec); 485 if (bt.sec != t) 486 boottimebin.sec += bt.sec - t; 487 } 488 /* Update the UTC timestamps used by the get*() functions. */ 489 /* XXX shouldn't do this here. Should force non-`get' versions. */ 490 bintime2timeval(&bt, &th->th_microtime); 491 bintime2timespec(&bt, &th->th_nanotime); 492 493 /* Now is a good time to change timecounters. */ 494 if (th->th_counter != timecounter) { 495 th->th_counter = timecounter; 496 th->th_offset_count = ncount; 497 tc_min_ticktock_freq = max(1, timecounter->tc_frequency / 498 (((uint64_t)timecounter->tc_counter_mask + 1) / 3)); 499 } 500 501 /*- 502 * Recalculate the scaling factor. We want the number of 1/2^64 503 * fractions of a second per period of the hardware counter, taking 504 * into account the th_adjustment factor which the NTP PLL/adjtime(2) 505 * processing provides us with. 506 * 507 * The th_adjustment is nanoseconds per second with 32 bit binary 508 * fraction and we want 64 bit binary fraction of second: 509 * 510 * x = a * 2^32 / 10^9 = a * 4.294967296 511 * 512 * The range of th_adjustment is +/- 5000PPM so inside a 64bit int 513 * we can only multiply by about 850 without overflowing, that 514 * leaves no suitably precise fractions for multiply before divide. 515 * 516 * Divide before multiply with a fraction of 2199/512 results in a 517 * systematic undercompensation of 10PPM of th_adjustment. On a 518 * 5000PPM adjustment this is a 0.05PPM error. This is acceptable. 519 * 520 * We happily sacrifice the lowest of the 64 bits of our result 521 * to the goddess of code clarity. 522 * 523 */ 524 scale = (uint64_t)1 << 63; 525 scale += (th->th_adjustment / 1024) * 2199; 526 scale /= th->th_counter->tc_frequency; 527 th->th_scale = scale * 2; 528 529 /* 530 * Now that the struct timehands is again consistent, set the new 531 * generation number, making sure to not make it zero. 532 */ 533 if (++ogen == 0) 534 ogen = 1; 535 th->th_generation = ogen; 536 537 /* Go live with the new struct timehands. */ 538 time_second = th->th_microtime.tv_sec; 539 time_uptime = th->th_offset.sec; 540 timehands = th; 541 } 542 543 /* Report or change the active timecounter hardware. */ 544 static int 545 sysctl_kern_timecounter_hardware(SYSCTL_HANDLER_ARGS) 546 { 547 char newname[32]; 548 struct timecounter *newtc, *tc; 549 int error; 550 551 tc = timecounter; 552 strlcpy(newname, tc->tc_name, sizeof(newname)); 553 554 error = sysctl_handle_string(oidp, &newname[0], sizeof(newname), req); 555 if (error != 0 || req->newptr == NULL || 556 strcmp(newname, tc->tc_name) == 0) 557 return (error); 558 for (newtc = timecounters; newtc != NULL; newtc = newtc->tc_next) { 559 if (strcmp(newname, newtc->tc_name) != 0) 560 continue; 561 562 /* Warm up new timecounter. */ 563 (void)newtc->tc_get_timecount(newtc); 564 (void)newtc->tc_get_timecount(newtc); 565 566 timecounter = newtc; 567 return (0); 568 } 569 return (EINVAL); 570 } 571 572 SYSCTL_PROC(_kern_timecounter, OID_AUTO, hardware, CTLTYPE_STRING | CTLFLAG_RW, 573 0, 0, sysctl_kern_timecounter_hardware, "A", 574 "Timecounter hardware selected"); 575 576 577 /* Report or change the active timecounter hardware. */ 578 static int 579 sysctl_kern_timecounter_choice(SYSCTL_HANDLER_ARGS) 580 { 581 char buf[32], *spc; 582 struct timecounter *tc; 583 int error; 584 585 spc = ""; 586 error = 0; 587 for (tc = timecounters; error == 0 && tc != NULL; tc = tc->tc_next) { 588 sprintf(buf, "%s%s(%d)", 589 spc, tc->tc_name, tc->tc_quality); 590 error = SYSCTL_OUT(req, buf, strlen(buf)); 591 spc = " "; 592 } 593 return (error); 594 } 595 596 SYSCTL_PROC(_kern_timecounter, OID_AUTO, choice, CTLTYPE_STRING | CTLFLAG_RD, 597 0, 0, sysctl_kern_timecounter_choice, "A", "Timecounter hardware detected"); 598 599 /* 600 * RFC 2783 PPS-API implementation. 601 */ 602 603 int 604 pps_ioctl(u_long cmd, caddr_t data, struct pps_state *pps) 605 { 606 pps_params_t *app; 607 struct pps_fetch_args *fapi; 608 #ifdef PPS_SYNC 609 struct pps_kcbind_args *kapi; 610 #endif 611 612 KASSERT(pps != NULL, ("NULL pps pointer in pps_ioctl")); 613 switch (cmd) { 614 case PPS_IOC_CREATE: 615 return (0); 616 case PPS_IOC_DESTROY: 617 return (0); 618 case PPS_IOC_SETPARAMS: 619 app = (pps_params_t *)data; 620 if (app->mode & ~pps->ppscap) 621 return (EINVAL); 622 pps->ppsparam = *app; 623 return (0); 624 case PPS_IOC_GETPARAMS: 625 app = (pps_params_t *)data; 626 *app = pps->ppsparam; 627 app->api_version = PPS_API_VERS_1; 628 return (0); 629 case PPS_IOC_GETCAP: 630 *(int*)data = pps->ppscap; 631 return (0); 632 case PPS_IOC_FETCH: 633 fapi = (struct pps_fetch_args *)data; 634 if (fapi->tsformat && fapi->tsformat != PPS_TSFMT_TSPEC) 635 return (EINVAL); 636 if (fapi->timeout.tv_sec || fapi->timeout.tv_nsec) 637 return (EOPNOTSUPP); 638 pps->ppsinfo.current_mode = pps->ppsparam.mode; 639 fapi->pps_info_buf = pps->ppsinfo; 640 return (0); 641 case PPS_IOC_KCBIND: 642 #ifdef PPS_SYNC 643 kapi = (struct pps_kcbind_args *)data; 644 /* XXX Only root should be able to do this */ 645 if (kapi->tsformat && kapi->tsformat != PPS_TSFMT_TSPEC) 646 return (EINVAL); 647 if (kapi->kernel_consumer != PPS_KC_HARDPPS) 648 return (EINVAL); 649 if (kapi->edge & ~pps->ppscap) 650 return (EINVAL); 651 pps->kcmode = kapi->edge; 652 return (0); 653 #else 654 return (EOPNOTSUPP); 655 #endif 656 default: 657 return (ENOIOCTL); 658 } 659 } 660 661 void 662 pps_init(struct pps_state *pps) 663 { 664 pps->ppscap |= PPS_TSFMT_TSPEC; 665 if (pps->ppscap & PPS_CAPTUREASSERT) 666 pps->ppscap |= PPS_OFFSETASSERT; 667 if (pps->ppscap & PPS_CAPTURECLEAR) 668 pps->ppscap |= PPS_OFFSETCLEAR; 669 } 670 671 void 672 pps_capture(struct pps_state *pps) 673 { 674 struct timehands *th; 675 676 KASSERT(pps != NULL, ("NULL pps pointer in pps_capture")); 677 th = timehands; 678 pps->capgen = th->th_generation; 679 pps->capth = th; 680 pps->capcount = th->th_counter->tc_get_timecount(th->th_counter); 681 if (pps->capgen != th->th_generation) 682 pps->capgen = 0; 683 } 684 685 void 686 pps_event(struct pps_state *pps, int event) 687 { 688 struct bintime bt; 689 struct timespec ts, *tsp, *osp; 690 u_int tcount, *pcount; 691 int foff, fhard; 692 pps_seq_t *pseq; 693 694 KASSERT(pps != NULL, ("NULL pps pointer in pps_event")); 695 /* If the timecounter was wound up underneath us, bail out. */ 696 if (pps->capgen == 0 || pps->capgen != pps->capth->th_generation) 697 return; 698 699 /* Things would be easier with arrays. */ 700 if (event == PPS_CAPTUREASSERT) { 701 tsp = &pps->ppsinfo.assert_timestamp; 702 osp = &pps->ppsparam.assert_offset; 703 foff = pps->ppsparam.mode & PPS_OFFSETASSERT; 704 fhard = pps->kcmode & PPS_CAPTUREASSERT; 705 pcount = &pps->ppscount[0]; 706 pseq = &pps->ppsinfo.assert_sequence; 707 } else { 708 tsp = &pps->ppsinfo.clear_timestamp; 709 osp = &pps->ppsparam.clear_offset; 710 foff = pps->ppsparam.mode & PPS_OFFSETCLEAR; 711 fhard = pps->kcmode & PPS_CAPTURECLEAR; 712 pcount = &pps->ppscount[1]; 713 pseq = &pps->ppsinfo.clear_sequence; 714 } 715 716 /* 717 * If the timecounter changed, we cannot compare the count values, so 718 * we have to drop the rest of the PPS-stuff until the next event. 719 */ 720 if (pps->ppstc != pps->capth->th_counter) { 721 pps->ppstc = pps->capth->th_counter; 722 *pcount = pps->capcount; 723 pps->ppscount[2] = pps->capcount; 724 return; 725 } 726 727 /* Convert the count to a timespec. */ 728 tcount = pps->capcount - pps->capth->th_offset_count; 729 tcount &= pps->capth->th_counter->tc_counter_mask; 730 bt = pps->capth->th_offset; 731 bintime_addx(&bt, pps->capth->th_scale * tcount); 732 bintime_add(&bt, &boottimebin); 733 bintime2timespec(&bt, &ts); 734 735 /* If the timecounter was wound up underneath us, bail out. */ 736 if (pps->capgen != pps->capth->th_generation) 737 return; 738 739 *pcount = pps->capcount; 740 (*pseq)++; 741 *tsp = ts; 742 743 if (foff) { 744 timespecadd(tsp, osp); 745 if (tsp->tv_nsec < 0) { 746 tsp->tv_nsec += 1000000000; 747 tsp->tv_sec -= 1; 748 } 749 } 750 #ifdef PPS_SYNC 751 if (fhard) { 752 uint64_t scale; 753 754 /* 755 * Feed the NTP PLL/FLL. 756 * The FLL wants to know how many (hardware) nanoseconds 757 * elapsed since the previous event. 758 */ 759 tcount = pps->capcount - pps->ppscount[2]; 760 pps->ppscount[2] = pps->capcount; 761 tcount &= pps->capth->th_counter->tc_counter_mask; 762 scale = (uint64_t)1 << 63; 763 scale /= pps->capth->th_counter->tc_frequency; 764 scale *= 2; 765 bt.sec = 0; 766 bt.frac = 0; 767 bintime_addx(&bt, scale * tcount); 768 bintime2timespec(&bt, &ts); 769 hardpps(tsp, ts.tv_nsec + 1000000000 * ts.tv_sec); 770 } 771 #endif 772 } 773 774 /* 775 * Timecounters need to be updated every so often to prevent the hardware 776 * counter from overflowing. Updating also recalculates the cached values 777 * used by the get*() family of functions, so their precision depends on 778 * the update frequency. 779 */ 780 781 static int tc_tick; 782 SYSCTL_INT(_kern_timecounter, OID_AUTO, tick, CTLFLAG_RD, &tc_tick, 0, 783 "Approximate number of hardclock ticks in a millisecond"); 784 785 void 786 tc_ticktock(int cnt) 787 { 788 static int count; 789 790 count += cnt; 791 if (count < tc_tick) 792 return; 793 count = 0; 794 tc_windup(); 795 } 796 797 static void 798 inittimecounter(void *dummy) 799 { 800 u_int p; 801 802 /* 803 * Set the initial timeout to 804 * max(1, <approx. number of hardclock ticks in a millisecond>). 805 * People should probably not use the sysctl to set the timeout 806 * to smaller than its inital value, since that value is the 807 * smallest reasonable one. If they want better timestamps they 808 * should use the non-"get"* functions. 809 */ 810 if (hz > 1000) 811 tc_tick = (hz + 500) / 1000; 812 else 813 tc_tick = 1; 814 p = (tc_tick * 1000000) / hz; 815 printf("Timecounters tick every %d.%03u msec\n", p / 1000, p % 1000); 816 817 /* warm up new timecounter (again) and get rolling. */ 818 (void)timecounter->tc_get_timecount(timecounter); 819 (void)timecounter->tc_get_timecount(timecounter); 820 tc_windup(); 821 } 822 823 SYSINIT(timecounter, SI_SUB_CLOCKS, SI_ORDER_SECOND, inittimecounter, NULL); 824 825 /* Cpu tick handling -------------------------------------------------*/ 826 827 static int cpu_tick_variable; 828 static uint64_t cpu_tick_frequency; 829 830 static uint64_t 831 tc_cpu_ticks(void) 832 { 833 static uint64_t base; 834 static unsigned last; 835 unsigned u; 836 struct timecounter *tc; 837 838 tc = timehands->th_counter; 839 u = tc->tc_get_timecount(tc) & tc->tc_counter_mask; 840 if (u < last) 841 base += (uint64_t)tc->tc_counter_mask + 1; 842 last = u; 843 return (u + base); 844 } 845 846 void 847 cpu_tick_calibration(void) 848 { 849 static time_t last_calib; 850 851 if (time_uptime != last_calib && !(time_uptime & 0xf)) { 852 cpu_tick_calibrate(0); 853 last_calib = time_uptime; 854 } 855 } 856 857 /* 858 * This function gets called every 16 seconds on only one designated 859 * CPU in the system from hardclock() via cpu_tick_calibration()(). 860 * 861 * Whenever the real time clock is stepped we get called with reset=1 862 * to make sure we handle suspend/resume and similar events correctly. 863 */ 864 865 static void 866 cpu_tick_calibrate(int reset) 867 { 868 static uint64_t c_last; 869 uint64_t c_this, c_delta; 870 static struct bintime t_last; 871 struct bintime t_this, t_delta; 872 uint32_t divi; 873 874 if (reset) { 875 /* The clock was stepped, abort & reset */ 876 t_last.sec = 0; 877 return; 878 } 879 880 /* we don't calibrate fixed rate cputicks */ 881 if (!cpu_tick_variable) 882 return; 883 884 getbinuptime(&t_this); 885 c_this = cpu_ticks(); 886 if (t_last.sec != 0) { 887 c_delta = c_this - c_last; 888 t_delta = t_this; 889 bintime_sub(&t_delta, &t_last); 890 /* 891 * Headroom: 892 * 2^(64-20) / 16[s] = 893 * 2^(44) / 16[s] = 894 * 17.592.186.044.416 / 16 = 895 * 1.099.511.627.776 [Hz] 896 */ 897 divi = t_delta.sec << 20; 898 divi |= t_delta.frac >> (64 - 20); 899 c_delta <<= 20; 900 c_delta /= divi; 901 if (c_delta > cpu_tick_frequency) { 902 if (0 && bootverbose) 903 printf("cpu_tick increased to %ju Hz\n", 904 c_delta); 905 cpu_tick_frequency = c_delta; 906 } 907 } 908 c_last = c_this; 909 t_last = t_this; 910 } 911 912 void 913 set_cputicker(cpu_tick_f *func, uint64_t freq, unsigned var) 914 { 915 916 if (func == NULL) { 917 cpu_ticks = tc_cpu_ticks; 918 } else { 919 cpu_tick_frequency = freq; 920 cpu_tick_variable = var; 921 cpu_ticks = func; 922 } 923 } 924 925 uint64_t 926 cpu_tickrate(void) 927 { 928 929 if (cpu_ticks == tc_cpu_ticks) 930 return (tc_getfrequency()); 931 return (cpu_tick_frequency); 932 } 933 934 /* 935 * We need to be slightly careful converting cputicks to microseconds. 936 * There is plenty of margin in 64 bits of microseconds (half a million 937 * years) and in 64 bits at 4 GHz (146 years), but if we do a multiply 938 * before divide conversion (to retain precision) we find that the 939 * margin shrinks to 1.5 hours (one millionth of 146y). 940 * With a three prong approach we never lose significant bits, no 941 * matter what the cputick rate and length of timeinterval is. 942 */ 943 944 uint64_t 945 cputick2usec(uint64_t tick) 946 { 947 948 if (tick > 18446744073709551LL) /* floor(2^64 / 1000) */ 949 return (tick / (cpu_tickrate() / 1000000LL)); 950 else if (tick > 18446744073709LL) /* floor(2^64 / 1000000) */ 951 return ((tick * 1000LL) / (cpu_tickrate() / 1000LL)); 952 else 953 return ((tick * 1000000LL) / cpu_tickrate()); 954 } 955 956 cpu_tick_f *cpu_ticks = tc_cpu_ticks; 957