sys/kern/kern_tc.c

   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         u_int64_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 time_t time_second = 1;
  91 time_t time_uptime = 1;
  92
  93 static struct bintime boottimebin;
  94 struct timeval boottime;
  95 static int sysctl_kern_boottime(SYSCTL_HANDLER_ARGS);
  96 SYSCTL_PROC(_kern, KERN_BOOTTIME, boottime, CTLTYPE_STRUCT|CTLFLAG_RD,
  97     NULL, 0, sysctl_kern_boottime, "S,timeval", "System boottime");
  98
  99 SYSCTL_NODE(_kern, OID_AUTO, timecounter, CTLFLAG_RW, 0, "");
 100 SYSCTL_NODE(_kern_timecounter, OID_AUTO, tc, CTLFLAG_RW, 0, "");
 101
 102 static int timestepwarnings;
 103 SYSCTL_INT(_kern_timecounter, OID_AUTO, stepwarnings, CTLFLAG_RW,
 104     &timestepwarnings, 0, "");
 105
 106 #define TC_STATS(foo) \
 107         static u_int foo; \
 108         SYSCTL_UINT(_kern_timecounter, OID_AUTO, foo, CTLFLAG_RD, &foo, 0, "");\
 109         struct __hack
 110
 111 TC_STATS(nbinuptime);    TC_STATS(nnanouptime);    TC_STATS(nmicrouptime);
 112 TC_STATS(nbintime);      TC_STATS(nnanotime);      TC_STATS(nmicrotime);
 113 TC_STATS(ngetbinuptime); TC_STATS(ngetnanouptime); TC_STATS(ngetmicrouptime);
 114 TC_STATS(ngetbintime);   TC_STATS(ngetnanotime);   TC_STATS(ngetmicrotime);
 115 TC_STATS(nsetclock);
 116
 117 #undef TC_STATS
 118
 119 static void tc_windup(void);
 120 static void cpu_tick_calibrate(int);
 121
 122 static int
 123 sysctl_kern_boottime(SYSCTL_HANDLER_ARGS)
 124 {
 125 #ifdef SCTL_MASK32
 126         int tv[2];
 127
 128         if (req->flags & SCTL_MASK32) {
 129                 tv[0] = boottime.tv_sec;
 130                 tv[1] = boottime.tv_usec;
 131                 return SYSCTL_OUT(req, tv, sizeof(tv));
 132         } else
 133 #endif
 134                 return SYSCTL_OUT(req, &boottime, sizeof(boottime));
 135 }
 136
 137 static int
 138 sysctl_kern_timecounter_get(SYSCTL_HANDLER_ARGS)
 139 {
 140         u_int ncount;
 141         struct timecounter *tc = arg1;
 142
 143         ncount = tc->tc_get_timecount(tc);
 144         return sysctl_handle_int(oidp, &ncount, 0, req);
 145 }
 146
 147 static int
 148 sysctl_kern_timecounter_freq(SYSCTL_HANDLER_ARGS)
 149 {
 150         u_int64_t freq;
 151         struct timecounter *tc = arg1;
 152
 153         freq = tc->tc_frequency;
 154         return sysctl_handle_quad(oidp, &freq, 0, req);
 155 }
 156
 157 /*
 158  * Return the difference between the timehands' counter value now and what
 159  * was when we copied it to the timehands' offset_count.
 160  */
 161 static __inline u_int
 162 tc_delta(struct timehands *th)
 163 {
 164         struct timecounter *tc;
 165
 166         tc = th->th_counter;
 167         return ((tc->tc_get_timecount(tc) - th->th_offset_count) &
 168             tc->tc_counter_mask);
 169 }
 170
 171 /*
 172  * Functions for reading the time.  We have to loop until we are sure that
 173  * the timehands that we operated on was not updated under our feet.  See
 174  * the comment in <sys/time.h> for a description of these 12 functions.
 175  */
 176
 177 void
 178 binuptime(struct bintime *bt)
 179 {
 180         struct timehands *th;
 181         u_int gen;
 182
 183         nbinuptime++;
 184         do {
 185                 th = timehands;
 186                 gen = th->th_generation;
 187                 *bt = th->th_offset;
 188                 bintime_addx(bt, th->th_scale * tc_delta(th));
 189         } while (gen == 0 || gen != th->th_generation);
 190 }
 191
 192 void
 193 nanouptime(struct timespec *tsp)
 194 {
 195         struct bintime bt;
 196
 197         nnanouptime++;
 198         binuptime(&bt);
 199         bintime2timespec(&bt, tsp);
 200 }
 201
 202 void
 203 microuptime(struct timeval *tvp)
 204 {
 205         struct bintime bt;
 206
 207         nmicrouptime++;
 208         binuptime(&bt);
 209         bintime2timeval(&bt, tvp);
 210 }
 211
 212 void
 213 bintime(struct bintime *bt)
 214 {
 215
 216         nbintime++;
 217         binuptime(bt);
 218         bintime_add(bt, &boottimebin);
 219 }
 220
 221 void
 222 nanotime(struct timespec *tsp)
 223 {
 224         struct bintime bt;
 225
 226         nnanotime++;
 227         bintime(&bt);
 228         bintime2timespec(&bt, tsp);
 229 }
 230
 231 void
 232 microtime(struct timeval *tvp)
 233 {
 234         struct bintime bt;
 235
 236         nmicrotime++;
 237         bintime(&bt);
 238         bintime2timeval(&bt, tvp);
 239 }
 240
 241 void
 242 getbinuptime(struct bintime *bt)
 243 {
 244         struct timehands *th;
 245         u_int gen;
 246
 247         ngetbinuptime++;
 248         do {
 249                 th = timehands;
 250                 gen = th->th_generation;
 251                 *bt = th->th_offset;
 252         } while (gen == 0 || gen != th->th_generation);
 253 }
 254
 255 void
 256 getnanouptime(struct timespec *tsp)
 257 {
 258         struct timehands *th;
 259         u_int gen;
 260
 261         ngetnanouptime++;
 262         do {
 263                 th = timehands;
 264                 gen = th->th_generation;
 265                 bintime2timespec(&th->th_offset, tsp);
 266         } while (gen == 0 || gen != th->th_generation);
 267 }
 268
 269 void
 270 getmicrouptime(struct timeval *tvp)
 271 {
 272         struct timehands *th;
 273         u_int gen;
 274
 275         ngetmicrouptime++;
 276         do {
 277                 th = timehands;
 278                 gen = th->th_generation;
 279                 bintime2timeval(&th->th_offset, tvp);
 280         } while (gen == 0 || gen != th->th_generation);
 281 }
 282
 283 void
 284 getbintime(struct bintime *bt)
 285 {
 286         struct timehands *th;
 287         u_int gen;
 288
 289         ngetbintime++;
 290         do {
 291                 th = timehands;
 292                 gen = th->th_generation;
 293                 *bt = th->th_offset;
 294         } while (gen == 0 || gen != th->th_generation);
 295         bintime_add(bt, &boottimebin);
 296 }
 297
 298 void
 299 getnanotime(struct timespec *tsp)
 300 {
 301         struct timehands *th;
 302         u_int gen;
 303
 304         ngetnanotime++;
 305         do {
 306                 th = timehands;
 307                 gen = th->th_generation;
 308                 *tsp = th->th_nanotime;
 309         } while (gen == 0 || gen != th->th_generation);
 310 }
 311
 312 void
 313 getmicrotime(struct timeval *tvp)
 314 {
 315         struct timehands *th;
 316         u_int gen;
 317
 318         ngetmicrotime++;
 319         do {
 320                 th = timehands;
 321                 gen = th->th_generation;
 322                 *tvp = th->th_microtime;
 323         } while (gen == 0 || gen != th->th_generation);
 324 }
 325
 326 /*
 327  * Initialize a new timecounter and possibly use it.
 328  */
 329 void
 330 tc_init(struct timecounter *tc)
 331 {
 332         u_int u;
 333         struct sysctl_oid *tc_root;
 334
 335         u = tc->tc_frequency / tc->tc_counter_mask;
 336         /* XXX: We need some margin here, 10% is a guess */
 337         u *= 11;
 338         u /= 10;
 339         if (u > hz && tc->tc_quality >= 0) {
 340                 tc->tc_quality = -2000;
 341                 if (bootverbose) {
 342                         printf("Timecounter \"%s\" frequency %ju Hz",
 343                             tc->tc_name, (uintmax_t)tc->tc_frequency);
 344                         printf(" -- Insufficient hz, needs at least %u\n", u);
 345                 }
 346         } else if (tc->tc_quality >= 0 || bootverbose) {
 347                 printf("Timecounter \"%s\" frequency %ju Hz quality %d\n",
 348                     tc->tc_name, (uintmax_t)tc->tc_frequency,
 349                     tc->tc_quality);
 350         }
 351
 352         tc->tc_next = timecounters;
 353         timecounters = tc;
 354         /*
 355          * Set up sysctl tree for this counter.
 356          */
 357         tc_root = SYSCTL_ADD_NODE(NULL,
 358             SYSCTL_STATIC_CHILDREN(_kern_timecounter_tc), OID_AUTO, tc->tc_name,
 359             CTLFLAG_RW, 0, "timecounter description");
 360         SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
 361             "mask", CTLFLAG_RD, &(tc->tc_counter_mask), 0,
 362             "mask for implemented bits");
 363         SYSCTL_ADD_PROC(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
 364             "counter", CTLTYPE_UINT | CTLFLAG_RD, tc, sizeof(*tc),
 365             sysctl_kern_timecounter_get, "IU", "current timecounter value");
 366         SYSCTL_ADD_PROC(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
 367             "frequency", CTLTYPE_QUAD | CTLFLAG_RD, tc, sizeof(*tc),
 368              sysctl_kern_timecounter_freq, "QU", "timecounter frequency");
 369         SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
 370             "quality", CTLFLAG_RD, &(tc->tc_quality), 0,
 371             "goodness of time counter");
 372         /*
 373          * Never automatically use a timecounter with negative quality.
 374          * Even though we run on the dummy counter, switching here may be
 375          * worse since this timecounter may not be monotonous.
 376          */
 377         if (tc->tc_quality < 0)
 378                 return;
 379         if (tc->tc_quality < timecounter->tc_quality)
 380                 return;
 381         if (tc->tc_quality == timecounter->tc_quality &&
 382             tc->tc_frequency < timecounter->tc_frequency)
 383                 return;
 384         (void)tc->tc_get_timecount(tc);
 385         (void)tc->tc_get_timecount(tc);
 386         timecounter = tc;
 387 }
 388
 389 /* Report the frequency of the current timecounter. */
 390 u_int64_t
 391 tc_getfrequency(void)
 392 {
 393
 394         return (timehands->th_counter->tc_frequency);
 395 }
 396
 397 /*
 398  * Step our concept of UTC.  This is done by modifying our estimate of
 399  * when we booted.
 400  * XXX: not locked.
 401  */
 402 void
 403 tc_setclock(struct timespec *ts)
 404 {
 405         struct timespec tbef, taft;
 406         struct bintime bt, bt2;
 407
 408         cpu_tick_calibrate(1);
 409         nsetclock++;
 410         nanotime(&tbef);
 411         timespec2bintime(ts, &bt);
 412         binuptime(&bt2);
 413         bintime_sub(&bt, &bt2);
 414         bintime_add(&bt2, &boottimebin);
 415         boottimebin = bt;
 416         bintime2timeval(&bt, &boottime);
 417
 418         /* XXX fiddle all the little crinkly bits around the fiords... */
 419         tc_windup();
 420         nanotime(&taft);
 421         if (timestepwarnings) {
 422                 log(LOG_INFO,
 423                     "Time stepped from %jd.%09ld to %jd.%09ld (%jd.%09ld)\n",
 424                     (intmax_t)tbef.tv_sec, tbef.tv_nsec,
 425                     (intmax_t)taft.tv_sec, taft.tv_nsec,
 426                     (intmax_t)ts->tv_sec, ts->tv_nsec);
 427         }
 428         cpu_tick_calibrate(1);
 429 }
 430
 431 /*
 432  * Initialize the next struct timehands in the ring and make
 433  * it the active timehands.  Along the way we might switch to a different
 434  * timecounter and/or do seconds processing in NTP.  Slightly magic.
 435  */
 436 static void
 437 tc_windup(void)
 438 {
 439         struct bintime bt;
 440         struct timehands *th, *tho;
 441         u_int64_t scale;
 442         u_int delta, ncount, ogen;
 443         int i;
 444         time_t t;
 445
 446         /*
 447          * Make the next timehands a copy of the current one, but do not
 448          * overwrite the generation or next pointer.  While we update
 449          * the contents, the generation must be zero.
 450          */
 451         tho = timehands;
 452         th = tho->th_next;
 453         ogen = th->th_generation;
 454         th->th_generation = 0;
 455         bcopy(tho, th, offsetof(struct timehands, th_generation));
 456
 457         /*
 458          * Capture a timecounter delta on the current timecounter and if
 459          * changing timecounters, a counter value from the new timecounter.
 460          * Update the offset fields accordingly.
 461          */
 462         delta = tc_delta(th);
 463         if (th->th_counter != timecounter)
 464                 ncount = timecounter->tc_get_timecount(timecounter);
 465         else
 466                 ncount = 0;
 467         th->th_offset_count += delta;
 468         th->th_offset_count &= th->th_counter->tc_counter_mask;
 469         bintime_addx(&th->th_offset, th->th_scale * delta);
 470
 471         /*
 472          * Hardware latching timecounters may not generate interrupts on
 473          * PPS events, so instead we poll them.  There is a finite risk that
 474          * the hardware might capture a count which is later than the one we
 475          * got above, and therefore possibly in the next NTP second which might
 476          * have a different rate than the current NTP second.  It doesn't
 477          * matter in practice.
 478          */
 479         if (tho->th_counter->tc_poll_pps)
 480                 tho->th_counter->tc_poll_pps(tho->th_counter);
 481
 482         /*
 483          * Deal with NTP second processing.  The for loop normally
 484          * iterates at most once, but in extreme situations it might
 485          * keep NTP sane if timeouts are not run for several seconds.
 486          * At boot, the time step can be large when the TOD hardware
 487          * has been read, so on really large steps, we call
 488          * ntp_update_second only twice.  We need to call it twice in
 489          * case we missed a leap second.
 490          */
 491         bt = th->th_offset;
 492         bintime_add(&bt, &boottimebin);
 493         i = bt.sec - tho->th_microtime.tv_sec;
 494         if (i > LARGE_STEP)
 495                 i = 2;
 496         for (; i > 0; i--) {
 497                 t = bt.sec;
 498                 ntp_update_second(&th->th_adjustment, &bt.sec);
 499                 if (bt.sec != t)
 500                         boottimebin.sec += bt.sec - t;
 501         }
 502         /* Update the UTC timestamps used by the get*() functions. */
 503         /* XXX shouldn't do this here.  Should force non-`get' versions. */
 504         bintime2timeval(&bt, &th->th_microtime);
 505         bintime2timespec(&bt, &th->th_nanotime);
 506
 507         /* Now is a good time to change timecounters. */
 508         if (th->th_counter != timecounter) {
 509                 th->th_counter = timecounter;
 510                 th->th_offset_count = ncount;
 511         }
 512
 513         /*-
 514          * Recalculate the scaling factor.  We want the number of 1/2^64
 515          * fractions of a second per period of the hardware counter, taking
 516          * into account the th_adjustment factor which the NTP PLL/adjtime(2)
 517          * processing provides us with.
 518          *
 519          * The th_adjustment is nanoseconds per second with 32 bit binary
 520          * fraction and we want 64 bit binary fraction of second:
 521          *
 522          *       x = a * 2^32 / 10^9 = a * 4.294967296
 523          *
 524          * The range of th_adjustment is +/- 5000PPM so inside a 64bit int
 525          * we can only multiply by about 850 without overflowing, that
 526          * leaves no suitably precise fractions for multiply before divide.
 527          *
 528          * Divide before multiply with a fraction of 2199/512 results in a
 529          * systematic undercompensation of 10PPM of th_adjustment.  On a
 530          * 5000PPM adjustment this is a 0.05PPM error.  This is acceptable.
 531          *
 532          * We happily sacrifice the lowest of the 64 bits of our result
 533          * to the goddess of code clarity.
 534          *
 535          */
 536         scale = (u_int64_t)1 << 63;
 537         scale += (th->th_adjustment / 1024) * 2199;
 538         scale /= th->th_counter->tc_frequency;
 539         th->th_scale = scale * 2;
 540
 541         /*
 542          * Now that the struct timehands is again consistent, set the new
 543          * generation number, making sure to not make it zero.
 544          */
 545         if (++ogen == 0)
 546                 ogen = 1;
 547         th->th_generation = ogen;
 548
 549         /* Go live with the new struct timehands. */
 550         time_second = th->th_microtime.tv_sec;
 551         time_uptime = th->th_offset.sec;
 552         timehands = th;
 553 }
 554
 555 /* Report or change the active timecounter hardware. */
 556 static int
 557 sysctl_kern_timecounter_hardware(SYSCTL_HANDLER_ARGS)
 558 {
 559         char newname[32];
 560         struct timecounter *newtc, *tc;
 561         int error;
 562
 563         tc = timecounter;
 564         strlcpy(newname, tc->tc_name, sizeof(newname));
 565
 566         error = sysctl_handle_string(oidp, &newname[0], sizeof(newname), req);
 567         if (error != 0 || req->newptr == NULL ||
 568             strcmp(newname, tc->tc_name) == 0)
 569                 return (error);
 570         for (newtc = timecounters; newtc != NULL; newtc = newtc->tc_next) {
 571                 if (strcmp(newname, newtc->tc_name) != 0)
 572                         continue;
 573
 574                 /* Warm up new timecounter. */
 575                 (void)newtc->tc_get_timecount(newtc);
 576                 (void)newtc->tc_get_timecount(newtc);
 577
 578                 timecounter = newtc;
 579                 return (0);
 580         }
 581         return (EINVAL);
 582 }
 583
 584 SYSCTL_PROC(_kern_timecounter, OID_AUTO, hardware, CTLTYPE_STRING | CTLFLAG_RW,
 585     0, 0, sysctl_kern_timecounter_hardware, "A", "");
 586
 587
 588 /* Report or change the active timecounter hardware. */
 589 static int
 590 sysctl_kern_timecounter_choice(SYSCTL_HANDLER_ARGS)
 591 {
 592         char buf[32], *spc;
 593         struct timecounter *tc;
 594         int error;
 595
 596         spc = "";
 597         error = 0;
 598         for (tc = timecounters; error == 0 && tc != NULL; tc = tc->tc_next) {
 599                 sprintf(buf, "%s%s(%d)",
 600                     spc, tc->tc_name, tc->tc_quality);
 601                 error = SYSCTL_OUT(req, buf, strlen(buf));
 602                 spc = " ";
 603         }
 604         return (error);
 605 }
 606
 607 SYSCTL_PROC(_kern_timecounter, OID_AUTO, choice, CTLTYPE_STRING | CTLFLAG_RD,
 608     0, 0, sysctl_kern_timecounter_choice, "A", "");
 609
 610 /*
 611  * RFC 2783 PPS-API implementation.
 612  */
 613
 614 int
 615 pps_ioctl(u_long cmd, caddr_t data, struct pps_state *pps)
 616 {
 617         pps_params_t *app;
 618         struct pps_fetch_args *fapi;
 619 #ifdef PPS_SYNC
 620         struct pps_kcbind_args *kapi;
 621 #endif
 622
 623         KASSERT(pps != NULL, ("NULL pps pointer in pps_ioctl"));
 624         switch (cmd) {
 625         case PPS_IOC_CREATE:
 626                 return (0);
 627         case PPS_IOC_DESTROY:
 628                 return (0);
 629         case PPS_IOC_SETPARAMS:
 630                 app = (pps_params_t *)data;
 631                 if (app->mode & ~pps->ppscap)
 632                         return (EINVAL);
 633                 pps->ppsparam = *app;
 634                 return (0);
 635         case PPS_IOC_GETPARAMS:
 636                 app = (pps_params_t *)data;
 637                 *app = pps->ppsparam;
 638                 app->api_version = PPS_API_VERS_1;
 639                 return (0);
 640         case PPS_IOC_GETCAP:
 641                 *(int*)data = pps->ppscap;
 642                 return (0);
 643         case PPS_IOC_FETCH:
 644                 fapi = (struct pps_fetch_args *)data;
 645                 if (fapi->tsformat && fapi->tsformat != PPS_TSFMT_TSPEC)
 646                         return (EINVAL);
 647                 if (fapi->timeout.tv_sec || fapi->timeout.tv_nsec)
 648                         return (EOPNOTSUPP);
 649                 pps->ppsinfo.current_mode = pps->ppsparam.mode;
 650                 fapi->pps_info_buf = pps->ppsinfo;
 651                 return (0);
 652         case PPS_IOC_KCBIND:
 653 #ifdef PPS_SYNC
 654                 kapi = (struct pps_kcbind_args *)data;
 655                 /* XXX Only root should be able to do this */
 656                 if (kapi->tsformat && kapi->tsformat != PPS_TSFMT_TSPEC)
 657                         return (EINVAL);
 658                 if (kapi->kernel_consumer != PPS_KC_HARDPPS)
 659                         return (EINVAL);
 660                 if (kapi->edge & ~pps->ppscap)
 661                         return (EINVAL);
 662                 pps->kcmode = kapi->edge;
 663                 return (0);
 664 #else
 665                 return (EOPNOTSUPP);
 666 #endif
 667         default:
 668                 return (ENOIOCTL);
 669         }
 670 }
 671
 672 void
 673 pps_init(struct pps_state *pps)
 674 {
 675         pps->ppscap |= PPS_TSFMT_TSPEC;
 676         if (pps->ppscap & PPS_CAPTUREASSERT)
 677                 pps->ppscap |= PPS_OFFSETASSERT;
 678         if (pps->ppscap & PPS_CAPTURECLEAR)
 679                 pps->ppscap |= PPS_OFFSETCLEAR;
 680 }
 681
 682 void
 683 pps_capture(struct pps_state *pps)
 684 {
 685         struct timehands *th;
 686
 687         KASSERT(pps != NULL, ("NULL pps pointer in pps_capture"));
 688         th = timehands;
 689         pps->capgen = th->th_generation;
 690         pps->capth = th;
 691         pps->capcount = th->th_counter->tc_get_timecount(th->th_counter);
 692         if (pps->capgen != th->th_generation)
 693                 pps->capgen = 0;
 694 }
 695
 696 void
 697 pps_event(struct pps_state *pps, int event)
 698 {
 699         struct bintime bt;
 700         struct timespec ts, *tsp, *osp;
 701         u_int tcount, *pcount;
 702         int foff, fhard;
 703         pps_seq_t *pseq;
 704
 705         KASSERT(pps != NULL, ("NULL pps pointer in pps_event"));
 706         /* If the timecounter was wound up underneath us, bail out. */
 707         if (pps->capgen == 0 || pps->capgen != pps->capth->th_generation)
 708                 return;
 709
 710         /* Things would be easier with arrays. */
 711         if (event == PPS_CAPTUREASSERT) {
 712                 tsp = &pps->ppsinfo.assert_timestamp;
 713                 osp = &pps->ppsparam.assert_offset;
 714                 foff = pps->ppsparam.mode & PPS_OFFSETASSERT;
 715                 fhard = pps->kcmode & PPS_CAPTUREASSERT;
 716                 pcount = &pps->ppscount[0];
 717                 pseq = &pps->ppsinfo.assert_sequence;
 718         } else {
 719                 tsp = &pps->ppsinfo.clear_timestamp;
 720                 osp = &pps->ppsparam.clear_offset;
 721                 foff = pps->ppsparam.mode & PPS_OFFSETCLEAR;
 722                 fhard = pps->kcmode & PPS_CAPTURECLEAR;
 723                 pcount = &pps->ppscount[1];
 724                 pseq = &pps->ppsinfo.clear_sequence;
 725         }
 726
 727         /*
 728          * If the timecounter changed, we cannot compare the count values, so
 729          * we have to drop the rest of the PPS-stuff until the next event.
 730          */
 731         if (pps->ppstc != pps->capth->th_counter) {
 732                 pps->ppstc = pps->capth->th_counter;
 733                 *pcount = pps->capcount;
 734                 pps->ppscount[2] = pps->capcount;
 735                 return;
 736         }
 737
 738         /* Convert the count to a timespec. */
 739         tcount = pps->capcount - pps->capth->th_offset_count;
 740         tcount &= pps->capth->th_counter->tc_counter_mask;
 741         bt = pps->capth->th_offset;
 742         bintime_addx(&bt, pps->capth->th_scale * tcount);
 743         bintime_add(&bt, &boottimebin);
 744         bintime2timespec(&bt, &ts);
 745
 746         /* If the timecounter was wound up underneath us, bail out. */
 747         if (pps->capgen != pps->capth->th_generation)
 748                 return;
 749
 750         *pcount = pps->capcount;
 751         (*pseq)++;
 752         *tsp = ts;
 753
 754         if (foff) {
 755                 timespecadd(tsp, osp);
 756                 if (tsp->tv_nsec < 0) {
 757                         tsp->tv_nsec += 1000000000;
 758                         tsp->tv_sec -= 1;
 759                 }
 760         }
 761 #ifdef PPS_SYNC
 762         if (fhard) {
 763                 u_int64_t scale;
 764
 765                 /*
 766                  * Feed the NTP PLL/FLL.
 767                  * The FLL wants to know how many (hardware) nanoseconds
 768                  * elapsed since the previous event.
 769                  */
 770                 tcount = pps->capcount - pps->ppscount[2];
 771                 pps->ppscount[2] = pps->capcount;
 772                 tcount &= pps->capth->th_counter->tc_counter_mask;
 773                 scale = (u_int64_t)1 << 63;
 774                 scale /= pps->capth->th_counter->tc_frequency;
 775                 scale *= 2;
 776                 bt.sec = 0;
 777                 bt.frac = 0;
 778                 bintime_addx(&bt, scale * tcount);
 779                 bintime2timespec(&bt, &ts);
 780                 hardpps(tsp, ts.tv_nsec + 1000000000 * ts.tv_sec);
 781         }
 782 #endif
 783 }
 784
 785 /*
 786  * Timecounters need to be updated every so often to prevent the hardware
 787  * counter from overflowing.  Updating also recalculates the cached values
 788  * used by the get*() family of functions, so their precision depends on
 789  * the update frequency.
 790  */
 791
 792 static int tc_tick;
 793 SYSCTL_INT(_kern_timecounter, OID_AUTO, tick, CTLFLAG_RD, &tc_tick, 0, "");
 794
 795 void
 796 tc_ticktock(void)
 797 {
 798         static int count;
 799         static time_t last_calib;
 800
 801         if (++count < tc_tick)
 802                 return;
 803         count = 0;
 804         tc_windup();
 805         if (time_uptime != last_calib && !(time_uptime & 0xf)) {
 806                 cpu_tick_calibrate(0);
 807                 last_calib = time_uptime;
 808         }
 809 }
 810
 811 static void
 812 inittimecounter(void *dummy)
 813 {
 814         u_int p;
 815
 816         /*
 817          * Set the initial timeout to
 818          * max(1, <approx. number of hardclock ticks in a millisecond>).
 819          * People should probably not use the sysctl to set the timeout
 820          * to smaller than its inital value, since that value is the
 821          * smallest reasonable one.  If they want better timestamps they
 822          * should use the non-"get"* functions.
 823          */
 824         if (hz > 1000)
 825                 tc_tick = (hz + 500) / 1000;
 826         else
 827                 tc_tick = 1;
 828         p = (tc_tick * 1000000) / hz;
 829         printf("Timecounters tick every %d.%03u msec\n", p / 1000, p % 1000);
 830
 831         /* warm up new timecounter (again) and get rolling. */
 832         (void)timecounter->tc_get_timecount(timecounter);
 833         (void)timecounter->tc_get_timecount(timecounter);
 834 }
 835
 836 SYSINIT(timecounter, SI_SUB_CLOCKS, SI_ORDER_SECOND, inittimecounter, NULL)
 837
 838 /* Cpu tick handling -------------------------------------------------*/
 839
 840 static int cpu_tick_variable;
 841 static uint64_t cpu_tick_frequency;
 842
 843 static uint64_t
 844 tc_cpu_ticks(void)
 845 {
 846         static uint64_t base;
 847         static unsigned last;
 848         unsigned u;
 849         struct timecounter *tc;
 850
 851         tc = timehands->th_counter;
 852         u = tc->tc_get_timecount(tc) & tc->tc_counter_mask;
 853         if (u < last)
 854                 base += (uint64_t)tc->tc_counter_mask + 1;
 855         last = u;
 856         return (u + base);
 857 }
 858
 859 /*
 860  * This function gets called ever 16 seconds on only one designated
 861  * CPU in the system from hardclock() via tc_ticktock().
 862  *
 863  * Whenever the real time clock is stepped we get called with reset=1
 864  * to make sure we handle suspend/resume and similar events correctly.
 865  */
 866
 867 static void
 868 cpu_tick_calibrate(int reset)
 869 {
 870         static uint64_t c_last;
 871         uint64_t c_this, c_delta;
 872         static struct bintime  t_last;
 873         struct bintime t_this, t_delta;
 874         uint32_t divi;
 875
 876         if (reset) {
 877                 /* The clock was stepped, abort & reset */
 878                 t_last.sec = 0;
 879                 return;
 880         }
 881
 882         /* we don't calibrate fixed rate cputicks */
 883         if (!cpu_tick_variable)
 884                 return;
 885
 886         getbinuptime(&t_this);
 887         c_this = cpu_ticks();
 888         if (t_last.sec != 0) {
 889                 c_delta = c_this - c_last;
 890                 t_delta = t_this;
 891                 bintime_sub(&t_delta, &t_last);
 892                 /*
 893                  * Validate that 16 +/- 1/256 seconds passed.
 894                  * After division by 16 this gives us a precision of
 895                  * roughly 250PPM which is sufficient
 896                  */
 897                 if (t_delta.sec > 16 || (
 898                     t_delta.sec == 16 && t_delta.frac >= (0x01LL << 56))) {
 899                         /* too long */
 900                         if (bootverbose)
 901                                 printf("%ju.%016jx too long\n",
 902                                     (uintmax_t)t_delta.sec,
 903                                     (uintmax_t)t_delta.frac);
 904                 } else if (t_delta.sec < 15 ||
 905                     (t_delta.sec == 15 && t_delta.frac <= (0xffLL << 56))) {
 906                         /* too short */
 907                         if (bootverbose)
 908                                 printf("%ju.%016jx too short\n",
 909                                     (uintmax_t)t_delta.sec,
 910                                     (uintmax_t)t_delta.frac);
 911                 } else {
 912                         /* just right */
 913                         /*
 914                          * Headroom:
 915                          *      2^(64-20) / 16[s] =
 916                          *      2^(44) / 16[s] =
 917                          *      17.592.186.044.416 / 16 =
 918                          *      1.099.511.627.776 [Hz]
 919                          */
 920                         divi = t_delta.sec << 20;
 921                         divi |= t_delta.frac >> (64 - 20);
 922                         c_delta <<= 20;
 923                         c_delta /= divi;
 924                         if (c_delta  > cpu_tick_frequency) {
 925                                 if (0 && bootverbose)
 926                                         printf("cpu_tick increased to %ju Hz\n",
 927                                             c_delta);
 928                                 cpu_tick_frequency = c_delta;
 929                         }
 930                 }
 931         }
 932         c_last = c_this;
 933         t_last = t_this;
 934 }
 935
 936 void
 937 set_cputicker(cpu_tick_f *func, uint64_t freq, unsigned var)
 938 {
 939
 940         if (func == NULL) {
 941                 cpu_ticks = tc_cpu_ticks;
 942         } else {
 943                 cpu_tick_frequency = freq;
 944                 cpu_tick_variable = var;
 945                 cpu_ticks = func;
 946         }
 947 }
 948
 949 uint64_t
 950 cpu_tickrate(void)
 951 {
 952
 953         if (cpu_ticks == tc_cpu_ticks)
 954                 return (tc_getfrequency());
 955         return (cpu_tick_frequency);
 956 }
 957
 958 /*
 959  * We need to be slightly careful converting cputicks to microseconds.
 960  * There is plenty of margin in 64 bits of microseconds (half a million
 961  * years) and in 64 bits at 4 GHz (146 years), but if we do a multiply
 962  * before divide conversion (to retain precision) we find that the
 963  * margin shrinks to 1.5 hours (one millionth of 146y).
 964  * With a three prong approach we never lose significant bits, no
 965  * matter what the cputick rate and length of timeinterval is.
 966  */
 967
 968 uint64_t
 969 cputick2usec(uint64_t tick)
 970 {
 971
 972         if (tick > 18446744073709551LL)         /* floor(2^64 / 1000) */
 973                 return (tick / (cpu_tickrate() / 1000000LL));
 974         else if (tick > 18446744073709LL)       /* floor(2^64 / 1000000) */
 975                 return ((tick * 1000LL) / (cpu_tickrate() / 1000LL));
 976         else
 977                 return ((tick * 1000000LL) / cpu_tickrate());
 978 }
 979
 980 cpu_tick_f      *cpu_ticks = tc_cpu_ticks;