sys/kern/kern_clocksource.c

   1 /*-
   2  * Copyright (c) 2010-2012 Alexander Motin <mav@FreeBSD.org>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer,
  10  *    without modification, immediately at the beginning of the file.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include <sys/cdefs.h>
  28 __FBSDID("$FreeBSD$");
  29
  30 /*
  31  * Common routines to manage event timers hardware.
  32  */
  33
  34 #include "opt_device_polling.h"
  35 #include "opt_kdtrace.h"
  36
  37 #include <sys/param.h>
  38 #include <sys/systm.h>
  39 #include <sys/bus.h>
  40 #include <sys/lock.h>
  41 #include <sys/kdb.h>
  42 #include <sys/ktr.h>
  43 #include <sys/mutex.h>
  44 #include <sys/proc.h>
  45 #include <sys/kernel.h>
  46 #include <sys/sched.h>
  47 #include <sys/smp.h>
  48 #include <sys/sysctl.h>
  49 #include <sys/timeet.h>
  50 #include <sys/timetc.h>
  51
  52 #include <machine/atomic.h>
  53 #include <machine/clock.h>
  54 #include <machine/cpu.h>
  55 #include <machine/smp.h>
  56
  57 #ifdef KDTRACE_HOOKS
  58 #include <sys/dtrace_bsd.h>
  59 cyclic_clock_func_t     cyclic_clock_func = NULL;
  60 #endif
  61
  62 int                     cpu_can_deep_sleep = 0; /* C3 state is available. */
  63 int                     cpu_disable_deep_sleep = 0; /* Timer dies in C3. */
  64
  65 static void             setuptimer(void);
  66 static void             loadtimer(struct bintime *now, int first);
  67 static int              doconfigtimer(void);
  68 static void             configtimer(int start);
  69 static int              round_freq(struct eventtimer *et, int freq);
  70
  71 static void             getnextcpuevent(struct bintime *event, int idle);
  72 static void             getnextevent(struct bintime *event);
  73 static int              handleevents(struct bintime *now, int fake);
  74 #ifdef SMP
  75 static void             cpu_new_callout(int cpu, int ticks);
  76 #endif
  77
  78 static struct mtx       et_hw_mtx;
  79
  80 #define ET_HW_LOCK(state)                                               \
  81         {                                                               \
  82                 if (timer->et_flags & ET_FLAGS_PERCPU)                  \
  83                         mtx_lock_spin(&(state)->et_hw_mtx);             \
  84                 else                                                    \
  85                         mtx_lock_spin(&et_hw_mtx);                      \
  86         }
  87
  88 #define ET_HW_UNLOCK(state)                                             \
  89         {                                                               \
  90                 if (timer->et_flags & ET_FLAGS_PERCPU)                  \
  91                         mtx_unlock_spin(&(state)->et_hw_mtx);           \
  92                 else                                                    \
  93                         mtx_unlock_spin(&et_hw_mtx);                    \
  94         }
  95
  96 static struct eventtimer *timer = NULL;
  97 static struct bintime   timerperiod;    /* Timer period for periodic mode. */
  98 static struct bintime   hardperiod;     /* hardclock() events period. */
  99 static struct bintime   statperiod;     /* statclock() events period. */
 100 static struct bintime   profperiod;     /* profclock() events period. */
 101 static struct bintime   nexttick;       /* Next global timer tick time. */
 102 static struct bintime   nexthard;       /* Next global hardlock() event. */
 103 static u_int            busy = 0;       /* Reconfiguration is in progress. */
 104 static int              profiling = 0;  /* Profiling events enabled. */
 105
 106 static char             timername[32];  /* Wanted timer. */
 107 TUNABLE_STR("kern.eventtimer.timer", timername, sizeof(timername));
 108
 109 static int              singlemul = 0;  /* Multiplier for periodic mode. */
 110 TUNABLE_INT("kern.eventtimer.singlemul", &singlemul);
 111 SYSCTL_INT(_kern_eventtimer, OID_AUTO, singlemul, CTLFLAG_RW, &singlemul,
 112     0, "Multiplier for periodic mode");
 113
 114 static u_int            idletick = 0;   /* Run periodic events when idle. */
 115 TUNABLE_INT("kern.eventtimer.idletick", &idletick);
 116 SYSCTL_UINT(_kern_eventtimer, OID_AUTO, idletick, CTLFLAG_RW, &idletick,
 117     0, "Run periodic events when idle");
 118
 119 static u_int            activetick = 1; /* Run all periodic events when active. */
 120 TUNABLE_INT("kern.eventtimer.activetick", &activetick);
 121 SYSCTL_UINT(_kern_eventtimer, OID_AUTO, activetick, CTLFLAG_RW, &activetick,
 122     0, "Run all periodic events when active");
 123
 124 static int              periodic = 0;   /* Periodic or one-shot mode. */
 125 static int              want_periodic = 0; /* What mode to prefer. */
 126 TUNABLE_INT("kern.eventtimer.periodic", &want_periodic);
 127
 128 struct pcpu_state {
 129         struct mtx      et_hw_mtx;      /* Per-CPU timer mutex. */
 130         u_int           action;         /* Reconfiguration requests. */
 131         u_int           handle;         /* Immediate handle resuests. */
 132         struct bintime  now;            /* Last tick time. */
 133         struct bintime  nextevent;      /* Next scheduled event on this CPU. */
 134         struct bintime  nexttick;       /* Next timer tick time. */
 135         struct bintime  nexthard;       /* Next hardlock() event. */
 136         struct bintime  nextstat;       /* Next statclock() event. */
 137         struct bintime  nextprof;       /* Next profclock() event. */
 138 #ifdef KDTRACE_HOOKS
 139         struct bintime  nextcyc;        /* Next OpenSolaris cyclics event. */
 140 #endif
 141         int             ipi;            /* This CPU needs IPI. */
 142         int             idle;           /* This CPU is in idle mode. */
 143 };
 144
 145 static DPCPU_DEFINE(struct pcpu_state, timerstate);
 146
 147 #define FREQ2BT(freq, bt)                                               \
 148 {                                                                       \
 149         (bt)->sec = 0;                                                  \
 150         (bt)->frac = ((uint64_t)0x8000000000000000  / (freq)) << 1;     \
 151 }
 152 #define BT2FREQ(bt)                                                     \
 153         (((uint64_t)0x8000000000000000 + ((bt)->frac >> 2)) /           \
 154             ((bt)->frac >> 1))
 155
 156 /*
 157  * Timer broadcast IPI handler.
 158  */
 159 int
 160 hardclockintr(void)
 161 {
 162         struct bintime now;
 163         struct pcpu_state *state;
 164         int done;
 165
 166         if (doconfigtimer() || busy)
 167                 return (FILTER_HANDLED);
 168         state = DPCPU_PTR(timerstate);
 169         now = state->now;
 170         CTR4(KTR_SPARE2, "ipi  at %d:    now  %d.%08x%08x",
 171             curcpu, now.sec, (u_int)(now.frac >> 32),
 172                              (u_int)(now.frac & 0xffffffff));
 173         done = handleevents(&now, 0);
 174         return (done ? FILTER_HANDLED : FILTER_STRAY);
 175 }
 176
 177 /*
 178  * Handle all events for specified time on this CPU
 179  */
 180 static int
 181 handleevents(struct bintime *now, int fake)
 182 {
 183         struct bintime t;
 184         struct trapframe *frame;
 185         struct pcpu_state *state;
 186         uintfptr_t pc;
 187         int usermode;
 188         int done, runs;
 189
 190         CTR4(KTR_SPARE2, "handle at %d:  now  %d.%08x%08x",
 191             curcpu, now->sec, (u_int)(now->frac >> 32),
 192                      (u_int)(now->frac & 0xffffffff));
 193         done = 0;
 194         if (fake) {
 195                 frame = NULL;
 196                 usermode = 0;
 197                 pc = 0;
 198         } else {
 199                 frame = curthread->td_intr_frame;
 200                 usermode = TRAPF_USERMODE(frame);
 201                 pc = TRAPF_PC(frame);
 202         }
 203
 204         state = DPCPU_PTR(timerstate);
 205
 206         runs = 0;
 207         while (bintime_cmp(now, &state->nexthard, >=)) {
 208                 bintime_addx(&state->nexthard, hardperiod.frac);
 209                 runs++;
 210         }
 211         if (runs) {
 212                 if ((timer->et_flags & ET_FLAGS_PERCPU) == 0 &&
 213                     bintime_cmp(&state->nexthard, &nexthard, >))
 214                         nexthard = state->nexthard;
 215                 if (fake < 2) {
 216                         hardclock_cnt(runs, usermode);
 217                         done = 1;
 218                 }
 219         }
 220         runs = 0;
 221         while (bintime_cmp(now, &state->nextstat, >=)) {
 222                 bintime_addx(&state->nextstat, statperiod.frac);
 223                 runs++;
 224         }
 225         if (runs && fake < 2) {
 226                 statclock_cnt(runs, usermode);
 227                 done = 1;
 228         }
 229         if (profiling) {
 230                 runs = 0;
 231                 while (bintime_cmp(now, &state->nextprof, >=)) {
 232                         bintime_addx(&state->nextprof, profperiod.frac);
 233                         runs++;
 234                 }
 235                 if (runs && !fake) {
 236                         profclock_cnt(runs, usermode, pc);
 237                         done = 1;
 238                 }
 239         } else
 240                 state->nextprof = state->nextstat;
 241
 242 #ifdef KDTRACE_HOOKS
 243         if (fake == 0 && cyclic_clock_func != NULL &&
 244             state->nextcyc.sec != -1 &&
 245             bintime_cmp(now, &state->nextcyc, >=)) {
 246                 state->nextcyc.sec = -1;
 247                 (*cyclic_clock_func)(frame);
 248         }
 249 #endif
 250
 251         getnextcpuevent(&t, 0);
 252         if (fake == 2) {
 253                 state->nextevent = t;
 254                 return (done);
 255         }
 256         ET_HW_LOCK(state);
 257         if (!busy) {
 258                 state->idle = 0;
 259                 state->nextevent = t;
 260                 loadtimer(now, 0);
 261         }
 262         ET_HW_UNLOCK(state);
 263         return (done);
 264 }
 265
 266 /*
 267  * Schedule binuptime of the next event on current CPU.
 268  */
 269 static void
 270 getnextcpuevent(struct bintime *event, int idle)
 271 {
 272         struct bintime tmp;
 273         struct pcpu_state *state;
 274         int skip;
 275
 276         state = DPCPU_PTR(timerstate);
 277         /* Handle hardclock() events. */
 278         *event = state->nexthard;
 279         if (idle || (!activetick && !profiling &&
 280             (timer->et_flags & ET_FLAGS_PERCPU) == 0)) {
 281                 skip = idle ? 4 : (stathz / 2);
 282                 if (curcpu == CPU_FIRST() && tc_min_ticktock_freq > skip)
 283                         skip = tc_min_ticktock_freq;
 284                 skip = callout_tickstofirst(hz / skip) - 1;
 285                 CTR2(KTR_SPARE2, "skip   at %d: %d", curcpu, skip);
 286                 tmp = hardperiod;
 287                 bintime_mul(&tmp, skip);
 288                 bintime_add(event, &tmp);
 289         }
 290         if (!idle) { /* If CPU is active - handle other types of events. */
 291                 if (bintime_cmp(event, &state->nextstat, >))
 292                         *event = state->nextstat;
 293                 if (profiling && bintime_cmp(event, &state->nextprof, >))
 294                         *event = state->nextprof;
 295         }
 296 #ifdef KDTRACE_HOOKS
 297         if (state->nextcyc.sec != -1 && bintime_cmp(event, &state->nextcyc, >))
 298                 *event = state->nextcyc;
 299 #endif
 300 }
 301
 302 /*
 303  * Schedule binuptime of the next event on all CPUs.
 304  */
 305 static void
 306 getnextevent(struct bintime *event)
 307 {
 308         struct pcpu_state *state;
 309 #ifdef SMP
 310         int     cpu;
 311 #endif
 312         int     c, nonidle;
 313
 314         state = DPCPU_PTR(timerstate);
 315         *event = state->nextevent;
 316         c = curcpu;
 317         nonidle = !state->idle;
 318         if ((timer->et_flags & ET_FLAGS_PERCPU) == 0) {
 319 #ifdef SMP
 320                 CPU_FOREACH(cpu) {
 321                         if (curcpu == cpu)
 322                                 continue;
 323                         state = DPCPU_ID_PTR(cpu, timerstate);
 324                         nonidle += !state->idle;
 325                         if (bintime_cmp(event, &state->nextevent, >)) {
 326                                 *event = state->nextevent;
 327                                 c = cpu;
 328                         }
 329                 }
 330 #endif
 331                 if (nonidle != 0 && bintime_cmp(event, &nexthard, >))
 332                         *event = nexthard;
 333         }
 334         CTR5(KTR_SPARE2, "next at %d:    next %d.%08x%08x by %d",
 335             curcpu, event->sec, (u_int)(event->frac >> 32),
 336                              (u_int)(event->frac & 0xffffffff), c);
 337 }
 338
 339 /* Hardware timer callback function. */
 340 static void
 341 timercb(struct eventtimer *et, void *arg)
 342 {
 343         struct bintime now;
 344         struct bintime *next;
 345         struct pcpu_state *state;
 346 #ifdef SMP
 347         int cpu, bcast;
 348 #endif
 349
 350         /* Do not touch anything if somebody reconfiguring timers. */
 351         if (busy)
 352                 return;
 353         /* Update present and next tick times. */
 354         state = DPCPU_PTR(timerstate);
 355         if (et->et_flags & ET_FLAGS_PERCPU) {
 356                 next = &state->nexttick;
 357         } else
 358                 next = &nexttick;
 359         binuptime(&now);
 360         if (periodic) {
 361                 *next = now;
 362                 bintime_addx(next, timerperiod.frac); /* Next tick in 1 period. */
 363         } else
 364                 next->sec = -1; /* Next tick is not scheduled yet. */
 365         state->now = now;
 366         CTR4(KTR_SPARE2, "intr at %d:    now  %d.%08x%08x",
 367             curcpu, (int)(now.sec), (u_int)(now.frac >> 32),
 368                              (u_int)(now.frac & 0xffffffff));
 369
 370 #ifdef SMP
 371         /* Prepare broadcasting to other CPUs for non-per-CPU timers. */
 372         bcast = 0;
 373         if ((et->et_flags & ET_FLAGS_PERCPU) == 0 && smp_started) {
 374                 CPU_FOREACH(cpu) {
 375                         state = DPCPU_ID_PTR(cpu, timerstate);
 376                         ET_HW_LOCK(state);
 377                         state->now = now;
 378                         if (bintime_cmp(&now, &state->nextevent, >=)) {
 379                                 state->nextevent.sec++;
 380                                 if (curcpu != cpu) {
 381                                         state->ipi = 1;
 382                                         bcast = 1;
 383                                 }
 384                         }
 385                         ET_HW_UNLOCK(state);
 386                 }
 387         }
 388 #endif
 389
 390         /* Handle events for this time on this CPU. */
 391         handleevents(&now, 0);
 392
 393 #ifdef SMP
 394         /* Broadcast interrupt to other CPUs for non-per-CPU timers. */
 395         if (bcast) {
 396                 CPU_FOREACH(cpu) {
 397                         if (curcpu == cpu)
 398                                 continue;
 399                         state = DPCPU_ID_PTR(cpu, timerstate);
 400                         if (state->ipi) {
 401                                 state->ipi = 0;
 402                                 ipi_cpu(cpu, IPI_HARDCLOCK);
 403                         }
 404                 }
 405         }
 406 #endif
 407 }
 408
 409 /*
 410  * Load new value into hardware timer.
 411  */
 412 static void
 413 loadtimer(struct bintime *now, int start)
 414 {
 415         struct pcpu_state *state;
 416         struct bintime new;
 417         struct bintime *next;
 418         uint64_t tmp;
 419         int eq;
 420
 421         if (timer->et_flags & ET_FLAGS_PERCPU) {
 422                 state = DPCPU_PTR(timerstate);
 423                 next = &state->nexttick;
 424         } else
 425                 next = &nexttick;
 426         if (periodic) {
 427                 if (start) {
 428                         /*
 429                          * Try to start all periodic timers aligned
 430                          * to period to make events synchronous.
 431                          */
 432                         tmp = ((uint64_t)now->sec << 36) + (now->frac >> 28);
 433                         tmp = (tmp % (timerperiod.frac >> 28)) << 28;
 434                         new.sec = 0;
 435                         new.frac = timerperiod.frac - tmp;
 436                         if (new.frac < tmp)     /* Left less then passed. */
 437                                 bintime_addx(&new, timerperiod.frac);
 438                         CTR5(KTR_SPARE2, "load p at %d:   now %d.%08x first in %d.%08x",
 439                             curcpu, now->sec, (u_int)(now->frac >> 32),
 440                             new.sec, (u_int)(new.frac >> 32));
 441                         *next = new;
 442                         bintime_add(next, now);
 443                         et_start(timer, &new, &timerperiod);
 444                 }
 445         } else {
 446                 getnextevent(&new);
 447                 eq = bintime_cmp(&new, next, ==);
 448                 CTR5(KTR_SPARE2, "load at %d:    next %d.%08x%08x eq %d",
 449                     curcpu, new.sec, (u_int)(new.frac >> 32),
 450                              (u_int)(new.frac & 0xffffffff),
 451                              eq);
 452                 if (!eq) {
 453                         *next = new;
 454                         bintime_sub(&new, now);
 455                         et_start(timer, &new, NULL);
 456                 }
 457         }
 458 }
 459
 460 /*
 461  * Prepare event timer parameters after configuration changes.
 462  */
 463 static void
 464 setuptimer(void)
 465 {
 466         int freq;
 467
 468         if (periodic && (timer->et_flags & ET_FLAGS_PERIODIC) == 0)
 469                 periodic = 0;
 470         else if (!periodic && (timer->et_flags & ET_FLAGS_ONESHOT) == 0)
 471                 periodic = 1;
 472         singlemul = MIN(MAX(singlemul, 1), 20);
 473         freq = hz * singlemul;
 474         while (freq < (profiling ? profhz : stathz))
 475                 freq += hz;
 476         freq = round_freq(timer, freq);
 477         FREQ2BT(freq, &timerperiod);
 478 }
 479
 480 /*
 481  * Reconfigure specified per-CPU timer on other CPU. Called from IPI handler.
 482  */
 483 static int
 484 doconfigtimer(void)
 485 {
 486         struct bintime now;
 487         struct pcpu_state *state;
 488
 489         state = DPCPU_PTR(timerstate);
 490         switch (atomic_load_acq_int(&state->action)) {
 491         case 1:
 492                 binuptime(&now);
 493                 ET_HW_LOCK(state);
 494                 loadtimer(&now, 1);
 495                 ET_HW_UNLOCK(state);
 496                 state->handle = 0;
 497                 atomic_store_rel_int(&state->action, 0);
 498                 return (1);
 499         case 2:
 500                 ET_HW_LOCK(state);
 501                 et_stop(timer);
 502                 ET_HW_UNLOCK(state);
 503                 state->handle = 0;
 504                 atomic_store_rel_int(&state->action, 0);
 505                 return (1);
 506         }
 507         if (atomic_readandclear_int(&state->handle) && !busy) {
 508                 binuptime(&now);
 509                 handleevents(&now, 0);
 510                 return (1);
 511         }
 512         return (0);
 513 }
 514
 515 /*
 516  * Reconfigure specified timer.
 517  * For per-CPU timers use IPI to make other CPUs to reconfigure.
 518  */
 519 static void
 520 configtimer(int start)
 521 {
 522         struct bintime now, next;
 523         struct pcpu_state *state;
 524         int cpu;
 525
 526         if (start) {
 527                 setuptimer();
 528                 binuptime(&now);
 529         }
 530         critical_enter();
 531         ET_HW_LOCK(DPCPU_PTR(timerstate));
 532         if (start) {
 533                 /* Initialize time machine parameters. */
 534                 next = now;
 535                 bintime_addx(&next, timerperiod.frac);
 536                 if (periodic)
 537                         nexttick = next;
 538                 else
 539                         nexttick.sec = -1;
 540                 CPU_FOREACH(cpu) {
 541                         state = DPCPU_ID_PTR(cpu, timerstate);
 542                         state->now = now;
 543                         state->nextevent = next;
 544                         if (periodic)
 545                                 state->nexttick = next;
 546                         else
 547                                 state->nexttick.sec = -1;
 548                         state->nexthard = next;
 549                         state->nextstat = next;
 550                         state->nextprof = next;
 551                         hardclock_sync(cpu);
 552                 }
 553                 busy = 0;
 554                 /* Start global timer or per-CPU timer of this CPU. */
 555                 loadtimer(&now, 1);
 556         } else {
 557                 busy = 1;
 558                 /* Stop global timer or per-CPU timer of this CPU. */
 559                 et_stop(timer);
 560         }
 561         ET_HW_UNLOCK(DPCPU_PTR(timerstate));
 562 #ifdef SMP
 563         /* If timer is global or there is no other CPUs yet - we are done. */
 564         if ((timer->et_flags & ET_FLAGS_PERCPU) == 0 || !smp_started) {
 565                 critical_exit();
 566                 return;
 567         }
 568         /* Set reconfigure flags for other CPUs. */
 569         CPU_FOREACH(cpu) {
 570                 state = DPCPU_ID_PTR(cpu, timerstate);
 571                 atomic_store_rel_int(&state->action,
 572                     (cpu == curcpu) ? 0 : ( start ? 1 : 2));
 573         }
 574         /* Broadcast reconfigure IPI. */
 575         ipi_all_but_self(IPI_HARDCLOCK);
 576         /* Wait for reconfiguration completed. */
 577 restart:
 578         cpu_spinwait();
 579         CPU_FOREACH(cpu) {
 580                 if (cpu == curcpu)
 581                         continue;
 582                 state = DPCPU_ID_PTR(cpu, timerstate);
 583                 if (atomic_load_acq_int(&state->action))
 584                         goto restart;
 585         }
 586 #endif
 587         critical_exit();
 588 }
 589
 590 /*
 591  * Calculate nearest frequency supported by hardware timer.
 592  */
 593 static int
 594 round_freq(struct eventtimer *et, int freq)
 595 {
 596         uint64_t div;
 597
 598         if (et->et_frequency != 0) {
 599                 div = lmax((et->et_frequency + freq / 2) / freq, 1);
 600                 if (et->et_flags & ET_FLAGS_POW2DIV)
 601                         div = 1 << (flsl(div + div / 2) - 1);
 602                 freq = (et->et_frequency + div / 2) / div;
 603         }
 604         if (et->et_min_period.sec > 0)
 605                 panic("Event timer \"%s\" doesn't support sub-second periods!",
 606                     et->et_name);
 607         else if (et->et_min_period.frac != 0)
 608                 freq = min(freq, BT2FREQ(&et->et_min_period));
 609         if (et->et_max_period.sec == 0 && et->et_max_period.frac != 0)
 610                 freq = max(freq, BT2FREQ(&et->et_max_period));
 611         return (freq);
 612 }
 613
 614 /*
 615  * Configure and start event timers (BSP part).
 616  */
 617 void
 618 cpu_initclocks_bsp(void)
 619 {
 620         struct pcpu_state *state;
 621         int base, div, cpu;
 622
 623         mtx_init(&et_hw_mtx, "et_hw_mtx", NULL, MTX_SPIN);
 624         CPU_FOREACH(cpu) {
 625                 state = DPCPU_ID_PTR(cpu, timerstate);
 626                 mtx_init(&state->et_hw_mtx, "et_hw_mtx", NULL, MTX_SPIN);
 627 #ifdef KDTRACE_HOOKS
 628                 state->nextcyc.sec = -1;
 629 #endif
 630         }
 631 #ifdef SMP
 632         callout_new_inserted = cpu_new_callout;
 633 #endif
 634         periodic = want_periodic;
 635         /* Grab requested timer or the best of present. */
 636         if (timername[0])
 637                 timer = et_find(timername, 0, 0);
 638         if (timer == NULL && periodic) {
 639                 timer = et_find(NULL,
 640                     ET_FLAGS_PERIODIC, ET_FLAGS_PERIODIC);
 641         }
 642         if (timer == NULL) {
 643                 timer = et_find(NULL,
 644                     ET_FLAGS_ONESHOT, ET_FLAGS_ONESHOT);
 645         }
 646         if (timer == NULL && !periodic) {
 647                 timer = et_find(NULL,
 648                     ET_FLAGS_PERIODIC, ET_FLAGS_PERIODIC);
 649         }
 650         if (timer == NULL)
 651                 panic("No usable event timer found!");
 652         et_init(timer, timercb, NULL, NULL);
 653
 654         /* Adapt to timer capabilities. */
 655         if (periodic && (timer->et_flags & ET_FLAGS_PERIODIC) == 0)
 656                 periodic = 0;
 657         else if (!periodic && (timer->et_flags & ET_FLAGS_ONESHOT) == 0)
 658                 periodic = 1;
 659         if (timer->et_flags & ET_FLAGS_C3STOP)
 660                 cpu_disable_deep_sleep++;
 661
 662         /*
 663          * We honor the requested 'hz' value.
 664          * We want to run stathz in the neighborhood of 128hz.
 665          * We would like profhz to run as often as possible.
 666          */
 667         if (singlemul <= 0 || singlemul > 20) {
 668                 if (hz >= 1500 || (hz % 128) == 0)
 669                         singlemul = 1;
 670                 else if (hz >= 750)
 671                         singlemul = 2;
 672                 else
 673                         singlemul = 4;
 674         }
 675         if (periodic) {
 676                 base = round_freq(timer, hz * singlemul);
 677                 singlemul = max((base + hz / 2) / hz, 1);
 678                 hz = (base + singlemul / 2) / singlemul;
 679                 if (base <= 128)
 680                         stathz = base;
 681                 else {
 682                         div = base / 128;
 683                         if (div >= singlemul && (div % singlemul) == 0)
 684                                 div++;
 685                         stathz = base / div;
 686                 }
 687                 profhz = stathz;
 688                 while ((profhz + stathz) <= 128 * 64)
 689                         profhz += stathz;
 690                 profhz = round_freq(timer, profhz);
 691         } else {
 692                 hz = round_freq(timer, hz);
 693                 stathz = round_freq(timer, 127);
 694                 profhz = round_freq(timer, stathz * 64);
 695         }
 696         tick = 1000000 / hz;
 697         FREQ2BT(hz, &hardperiod);
 698         FREQ2BT(stathz, &statperiod);
 699         FREQ2BT(profhz, &profperiod);
 700         ET_LOCK();
 701         configtimer(1);
 702         ET_UNLOCK();
 703 }
 704
 705 /*
 706  * Start per-CPU event timers on APs.
 707  */
 708 void
 709 cpu_initclocks_ap(void)
 710 {
 711         struct bintime now;
 712         struct pcpu_state *state;
 713
 714         state = DPCPU_PTR(timerstate);
 715         binuptime(&now);
 716         ET_HW_LOCK(state);
 717         state->now = now;
 718         hardclock_sync(curcpu);
 719         handleevents(&state->now, 2);
 720         if (timer->et_flags & ET_FLAGS_PERCPU)
 721                 loadtimer(&now, 1);
 722         ET_HW_UNLOCK(state);
 723 }
 724
 725 /*
 726  * Switch to profiling clock rates.
 727  */
 728 void
 729 cpu_startprofclock(void)
 730 {
 731
 732         ET_LOCK();
 733         if (periodic) {
 734                 configtimer(0);
 735                 profiling = 1;
 736                 configtimer(1);
 737         } else
 738                 profiling = 1;
 739         ET_UNLOCK();
 740 }
 741
 742 /*
 743  * Switch to regular clock rates.
 744  */
 745 void
 746 cpu_stopprofclock(void)
 747 {
 748
 749         ET_LOCK();
 750         if (periodic) {
 751                 configtimer(0);
 752                 profiling = 0;
 753                 configtimer(1);
 754         } else
 755                 profiling = 0;
 756         ET_UNLOCK();
 757 }
 758
 759 /*
 760  * Switch to idle mode (all ticks handled).
 761  */
 762 void
 763 cpu_idleclock(void)
 764 {
 765         struct bintime now, t;
 766         struct pcpu_state *state;
 767
 768         if (idletick || busy ||
 769             (periodic && (timer->et_flags & ET_FLAGS_PERCPU))
 770 #ifdef DEVICE_POLLING
 771             || curcpu == CPU_FIRST()
 772 #endif
 773             )
 774                 return;
 775         state = DPCPU_PTR(timerstate);
 776         if (periodic)
 777                 now = state->now;
 778         else
 779                 binuptime(&now);
 780         CTR4(KTR_SPARE2, "idle at %d:    now  %d.%08x%08x",
 781             curcpu, now.sec, (u_int)(now.frac >> 32),
 782                              (u_int)(now.frac & 0xffffffff));
 783         getnextcpuevent(&t, 1);
 784         ET_HW_LOCK(state);
 785         state->idle = 1;
 786         state->nextevent = t;
 787         if (!periodic)
 788                 loadtimer(&now, 0);
 789         ET_HW_UNLOCK(state);
 790 }
 791
 792 /*
 793  * Switch to active mode (skip empty ticks).
 794  */
 795 void
 796 cpu_activeclock(void)
 797 {
 798         struct bintime now;
 799         struct pcpu_state *state;
 800         struct thread *td;
 801
 802         state = DPCPU_PTR(timerstate);
 803         if (state->idle == 0 || busy)
 804                 return;
 805         if (periodic)
 806                 now = state->now;
 807         else
 808                 binuptime(&now);
 809         CTR4(KTR_SPARE2, "active at %d:  now  %d.%08x%08x",
 810             curcpu, now.sec, (u_int)(now.frac >> 32),
 811                              (u_int)(now.frac & 0xffffffff));
 812         spinlock_enter();
 813         td = curthread;
 814         td->td_intr_nesting_level++;
 815         handleevents(&now, 1);
 816         td->td_intr_nesting_level--;
 817         spinlock_exit();
 818 }
 819
 820 #ifdef KDTRACE_HOOKS
 821 void
 822 clocksource_cyc_set(const struct bintime *t)
 823 {
 824         struct bintime now;
 825         struct pcpu_state *state;
 826
 827         state = DPCPU_PTR(timerstate);
 828         if (periodic)
 829                 now = state->now;
 830         else
 831                 binuptime(&now);
 832
 833         CTR4(KTR_SPARE2, "set_cyc at %d:  now  %d.%08x%08x",
 834             curcpu, now.sec, (u_int)(now.frac >> 32),
 835                              (u_int)(now.frac & 0xffffffff));
 836         CTR4(KTR_SPARE2, "set_cyc at %d:  t  %d.%08x%08x",
 837             curcpu, t->sec, (u_int)(t->frac >> 32),
 838                              (u_int)(t->frac & 0xffffffff));
 839
 840         ET_HW_LOCK(state);
 841         if (bintime_cmp(t, &state->nextcyc, ==)) {
 842                 ET_HW_UNLOCK(state);
 843                 return;
 844         }
 845         state->nextcyc = *t;
 846         if (bintime_cmp(&state->nextcyc, &state->nextevent, >=)) {
 847                 ET_HW_UNLOCK(state);
 848                 return;
 849         }
 850         state->nextevent = state->nextcyc;
 851         if (!periodic)
 852                 loadtimer(&now, 0);
 853         ET_HW_UNLOCK(state);
 854 }
 855 #endif
 856
 857 #ifdef SMP
 858 static void
 859 cpu_new_callout(int cpu, int ticks)
 860 {
 861         struct bintime tmp;
 862         struct pcpu_state *state;
 863
 864         CTR3(KTR_SPARE2, "new co at %d:    on %d in %d",
 865             curcpu, cpu, ticks);
 866         state = DPCPU_ID_PTR(cpu, timerstate);
 867         ET_HW_LOCK(state);
 868         if (state->idle == 0 || busy) {
 869                 ET_HW_UNLOCK(state);
 870                 return;
 871         }
 872         /*
 873          * If timer is periodic - just update next event time for target CPU.
 874          * If timer is global - there is chance it is already programmed.
 875          */
 876         if (periodic || (timer->et_flags & ET_FLAGS_PERCPU) == 0) {
 877                 tmp = hardperiod;
 878                 bintime_mul(&tmp, ticks - 1);
 879                 bintime_add(&tmp, &state->nexthard);
 880                 if (bintime_cmp(&tmp, &state->nextevent, <))
 881                         state->nextevent = tmp;
 882                 if (periodic ||
 883                     bintime_cmp(&state->nextevent, &nexttick, >=)) {
 884                         ET_HW_UNLOCK(state);
 885                         return;
 886                 }
 887         }
 888         /*
 889          * Otherwise we have to wake that CPU up, as we can't get present
 890          * bintime to reprogram global timer from here. If timer is per-CPU,
 891          * we by definition can't do it from here.
 892          */
 893         ET_HW_UNLOCK(state);
 894         if (timer->et_flags & ET_FLAGS_PERCPU) {
 895                 state->handle = 1;
 896                 ipi_cpu(cpu, IPI_HARDCLOCK);
 897         } else {
 898                 if (!cpu_idle_wakeup(cpu))
 899                         ipi_cpu(cpu, IPI_AST);
 900         }
 901 }
 902 #endif
 903
 904 /*
 905  * Report or change the active event timers hardware.
 906  */
 907 static int
 908 sysctl_kern_eventtimer_timer(SYSCTL_HANDLER_ARGS)
 909 {
 910         char buf[32];
 911         struct eventtimer *et;
 912         int error;
 913
 914         ET_LOCK();
 915         et = timer;
 916         snprintf(buf, sizeof(buf), "%s", et->et_name);
 917         ET_UNLOCK();
 918         error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
 919         ET_LOCK();
 920         et = timer;
 921         if (error != 0 || req->newptr == NULL ||
 922             strcasecmp(buf, et->et_name) == 0) {
 923                 ET_UNLOCK();
 924                 return (error);
 925         }
 926         et = et_find(buf, 0, 0);
 927         if (et == NULL) {
 928                 ET_UNLOCK();
 929                 return (ENOENT);
 930         }
 931         configtimer(0);
 932         et_free(timer);
 933         if (et->et_flags & ET_FLAGS_C3STOP)
 934                 cpu_disable_deep_sleep++;
 935         if (timer->et_flags & ET_FLAGS_C3STOP)
 936                 cpu_disable_deep_sleep--;
 937         periodic = want_periodic;
 938         timer = et;
 939         et_init(timer, timercb, NULL, NULL);
 940         configtimer(1);
 941         ET_UNLOCK();
 942         return (error);
 943 }
 944 SYSCTL_PROC(_kern_eventtimer, OID_AUTO, timer,
 945     CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE,
 946     0, 0, sysctl_kern_eventtimer_timer, "A", "Chosen event timer");
 947
 948 /*
 949  * Report or change the active event timer periodicity.
 950  */
 951 static int
 952 sysctl_kern_eventtimer_periodic(SYSCTL_HANDLER_ARGS)
 953 {
 954         int error, val;
 955
 956         val = periodic;
 957         error = sysctl_handle_int(oidp, &val, 0, req);
 958         if (error != 0 || req->newptr == NULL)
 959                 return (error);
 960         ET_LOCK();
 961         configtimer(0);
 962         periodic = want_periodic = val;
 963         configtimer(1);
 964         ET_UNLOCK();
 965         return (error);
 966 }
 967 SYSCTL_PROC(_kern_eventtimer, OID_AUTO, periodic,
 968     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
 969     0, 0, sysctl_kern_eventtimer_periodic, "I", "Enable event timer periodic mode");