1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T     */
  22 /*        All Rights Reserved   */
  23 
  24 /*
  25  * Copyright (c) 1988, 2010, Oracle and/or its affiliates. All rights reserved.
  26  * Copyright (c) 2013, Joyent, Inc.  All rights reserved.
  27  * Copyright 2016 Garrett D'Amore
  28  */
  29 
  30 #include <sys/param.h>
  31 #include <sys/t_lock.h>
  32 #include <sys/types.h>
  33 #include <sys/tuneable.h>
  34 #include <sys/sysmacros.h>
  35 #include <sys/systm.h>
  36 #include <sys/cpuvar.h>
  37 #include <sys/lgrp.h>
  38 #include <sys/user.h>
  39 #include <sys/proc.h>
  40 #include <sys/callo.h>
  41 #include <sys/kmem.h>
  42 #include <sys/var.h>
  43 #include <sys/cmn_err.h>
  44 #include <sys/swap.h>
  45 #include <sys/vmsystm.h>
  46 #include <sys/class.h>
  47 #include <sys/time.h>
  48 #include <sys/debug.h>
  49 #include <sys/vtrace.h>
  50 #include <sys/spl.h>
  51 #include <sys/atomic.h>
  52 #include <sys/dumphdr.h>
  53 #include <sys/archsystm.h>
  54 #include <sys/fs/swapnode.h>
  55 #include <sys/panic.h>
  56 #include <sys/disp.h>
  57 #include <sys/msacct.h>
  58 #include <sys/mem_cage.h>
  59 
  60 #include <vm/page.h>
  61 #include <vm/anon.h>
  62 #include <vm/rm.h>
  63 #include <sys/cyclic.h>
  64 #include <sys/cpupart.h>
  65 #include <sys/rctl.h>
  66 #include <sys/task.h>
  67 #include <sys/sdt.h>
  68 #include <sys/ddi_periodic.h>
  69 #include <sys/random.h>
  70 #include <sys/modctl.h>
  71 #include <sys/zone.h>
  72 
  73 /*
  74  * for NTP support
  75  */
  76 #include <sys/timex.h>
  77 #include <sys/inttypes.h>
  78 
  79 #include <sys/sunddi.h>
  80 #include <sys/clock_impl.h>
  81 
  82 /*
  83  * clock() is called straight from the clock cyclic; see clock_init().
  84  *
  85  * Functions:
  86  *      reprime clock
  87  *      maintain date
  88  *      jab the scheduler
  89  */
  90 
  91 extern kcondvar_t       fsflush_cv;
  92 extern sysinfo_t        sysinfo;
  93 extern vminfo_t vminfo;
  94 extern int      idleswtch;      /* flag set while idle in pswtch() */
  95 extern hrtime_t volatile devinfo_freeze;
  96 
  97 /*
  98  * high-precision avenrun values.  These are needed to make the
  99  * regular avenrun values accurate.
 100  */
 101 static uint64_t hp_avenrun[3];
 102 int     avenrun[3];             /* FSCALED average run queue lengths */
 103 time_t  time;   /* time in seconds since 1970 - for compatibility only */
 104 
 105 static struct loadavg_s loadavg;
 106 /*
 107  * Phase/frequency-lock loop (PLL/FLL) definitions
 108  *
 109  * The following variables are read and set by the ntp_adjtime() system
 110  * call.
 111  *
 112  * time_state shows the state of the system clock, with values defined
 113  * in the timex.h header file.
 114  *
 115  * time_status shows the status of the system clock, with bits defined
 116  * in the timex.h header file.
 117  *
 118  * time_offset is used by the PLL/FLL to adjust the system time in small
 119  * increments.
 120  *
 121  * time_constant determines the bandwidth or "stiffness" of the PLL.
 122  *
 123  * time_tolerance determines maximum frequency error or tolerance of the
 124  * CPU clock oscillator and is a property of the architecture; however,
 125  * in principle it could change as result of the presence of external
 126  * discipline signals, for instance.
 127  *
 128  * time_precision is usually equal to the kernel tick variable; however,
 129  * in cases where a precision clock counter or external clock is
 130  * available, the resolution can be much less than this and depend on
 131  * whether the external clock is working or not.
 132  *
 133  * time_maxerror is initialized by a ntp_adjtime() call and increased by
 134  * the kernel once each second to reflect the maximum error bound
 135  * growth.
 136  *
 137  * time_esterror is set and read by the ntp_adjtime() call, but
 138  * otherwise not used by the kernel.
 139  */
 140 int32_t time_state = TIME_OK;   /* clock state */
 141 int32_t time_status = STA_UNSYNC;       /* clock status bits */
 142 int32_t time_offset = 0;                /* time offset (us) */
 143 int32_t time_constant = 0;              /* pll time constant */
 144 int32_t time_tolerance = MAXFREQ;       /* frequency tolerance (scaled ppm) */
 145 int32_t time_precision = 1;     /* clock precision (us) */
 146 int32_t time_maxerror = MAXPHASE;       /* maximum error (us) */
 147 int32_t time_esterror = MAXPHASE;       /* estimated error (us) */
 148 
 149 /*
 150  * The following variables establish the state of the PLL/FLL and the
 151  * residual time and frequency offset of the local clock. The scale
 152  * factors are defined in the timex.h header file.
 153  *
 154  * time_phase and time_freq are the phase increment and the frequency
 155  * increment, respectively, of the kernel time variable.
 156  *
 157  * time_freq is set via ntp_adjtime() from a value stored in a file when
 158  * the synchronization daemon is first started. Its value is retrieved
 159  * via ntp_adjtime() and written to the file about once per hour by the
 160  * daemon.
 161  *
 162  * time_adj is the adjustment added to the value of tick at each timer
 163  * interrupt and is recomputed from time_phase and time_freq at each
 164  * seconds rollover.
 165  *
 166  * time_reftime is the second's portion of the system time at the last
 167  * call to ntp_adjtime(). It is used to adjust the time_freq variable
 168  * and to increase the time_maxerror as the time since last update
 169  * increases.
 170  */
 171 int32_t time_phase = 0;         /* phase offset (scaled us) */
 172 int32_t time_freq = 0;          /* frequency offset (scaled ppm) */
 173 int32_t time_adj = 0;           /* tick adjust (scaled 1 / hz) */
 174 int32_t time_reftime = 0;               /* time at last adjustment (s) */
 175 
 176 /*
 177  * The scale factors of the following variables are defined in the
 178  * timex.h header file.
 179  *
 180  * pps_time contains the time at each calibration interval, as read by
 181  * microtime(). pps_count counts the seconds of the calibration
 182  * interval, the duration of which is nominally pps_shift in powers of
 183  * two.
 184  *
 185  * pps_offset is the time offset produced by the time median filter
 186  * pps_tf[], while pps_jitter is the dispersion (jitter) measured by
 187  * this filter.
 188  *
 189  * pps_freq is the frequency offset produced by the frequency median
 190  * filter pps_ff[], while pps_stabil is the dispersion (wander) measured
 191  * by this filter.
 192  *
 193  * pps_usec is latched from a high resolution counter or external clock
 194  * at pps_time. Here we want the hardware counter contents only, not the
 195  * contents plus the time_tv.usec as usual.
 196  *
 197  * pps_valid counts the number of seconds since the last PPS update. It
 198  * is used as a watchdog timer to disable the PPS discipline should the
 199  * PPS signal be lost.
 200  *
 201  * pps_glitch counts the number of seconds since the beginning of an
 202  * offset burst more than tick/2 from current nominal offset. It is used
 203  * mainly to suppress error bursts due to priority conflicts between the
 204  * PPS interrupt and timer interrupt.
 205  *
 206  * pps_intcnt counts the calibration intervals for use in the interval-
 207  * adaptation algorithm. It's just too complicated for words.
 208  */
 209 struct timeval pps_time;        /* kernel time at last interval */
 210 int32_t pps_tf[] = {0, 0, 0};   /* pps time offset median filter (us) */
 211 int32_t pps_offset = 0;         /* pps time offset (us) */
 212 int32_t pps_jitter = MAXTIME;   /* time dispersion (jitter) (us) */
 213 int32_t pps_ff[] = {0, 0, 0};   /* pps frequency offset median filter */
 214 int32_t pps_freq = 0;           /* frequency offset (scaled ppm) */
 215 int32_t pps_stabil = MAXFREQ;   /* frequency dispersion (scaled ppm) */
 216 int32_t pps_usec = 0;           /* microsec counter at last interval */
 217 int32_t pps_valid = PPS_VALID;  /* pps signal watchdog counter */
 218 int32_t pps_glitch = 0;         /* pps signal glitch counter */
 219 int32_t pps_count = 0;          /* calibration interval counter (s) */
 220 int32_t pps_shift = PPS_SHIFT;  /* interval duration (s) (shift) */
 221 int32_t pps_intcnt = 0;         /* intervals at current duration */
 222 
 223 /*
 224  * PPS signal quality monitors
 225  *
 226  * pps_jitcnt counts the seconds that have been discarded because the
 227  * jitter measured by the time median filter exceeds the limit MAXTIME
 228  * (100 us).
 229  *
 230  * pps_calcnt counts the frequency calibration intervals, which are
 231  * variable from 4 s to 256 s.
 232  *
 233  * pps_errcnt counts the calibration intervals which have been discarded
 234  * because the wander exceeds the limit MAXFREQ (100 ppm) or where the
 235  * calibration interval jitter exceeds two ticks.
 236  *
 237  * pps_stbcnt counts the calibration intervals that have been discarded
 238  * because the frequency wander exceeds the limit MAXFREQ / 4 (25 us).
 239  */
 240 int32_t pps_jitcnt = 0;         /* jitter limit exceeded */
 241 int32_t pps_calcnt = 0;         /* calibration intervals */
 242 int32_t pps_errcnt = 0;         /* calibration errors */
 243 int32_t pps_stbcnt = 0;         /* stability limit exceeded */
 244 
 245 kcondvar_t lbolt_cv;
 246 
 247 /*
 248  * Hybrid lbolt implementation:
 249  *
 250  * The service historically provided by the lbolt and lbolt64 variables has
 251  * been replaced by the ddi_get_lbolt() and ddi_get_lbolt64() routines, and the
 252  * original symbols removed from the system. The once clock driven variables are
 253  * now implemented in an event driven fashion, backed by gethrtime() coarsed to
 254  * the appropriate clock resolution. The default event driven implementation is
 255  * complemented by a cyclic driven one, active only during periods of intense
 256  * activity around the DDI lbolt routines, when a lbolt specific cyclic is
 257  * reprogramed to fire at a clock tick interval to serve consumers of lbolt who
 258  * rely on the original low cost of consulting a memory position.
 259  *
 260  * The implementation uses the number of calls to these routines and the
 261  * frequency of these to determine when to transition from event to cyclic
 262  * driven and vice-versa. These values are kept on a per CPU basis for
 263  * scalability reasons and to prevent CPUs from constantly invalidating a single
 264  * cache line when modifying a global variable. The transition from event to
 265  * cyclic mode happens once the thresholds are crossed, and activity on any CPU
 266  * can cause such transition.
 267  *
 268  * The lbolt_hybrid function pointer is called by ddi_get_lbolt() and
 269  * ddi_get_lbolt64(), and will point to lbolt_event_driven() or
 270  * lbolt_cyclic_driven() according to the current mode. When the thresholds
 271  * are exceeded, lbolt_event_driven() will reprogram the lbolt cyclic to
 272  * fire at a nsec_per_tick interval and increment an internal variable at
 273  * each firing. lbolt_hybrid will then point to lbolt_cyclic_driven(), which
 274  * will simply return the value of such variable. lbolt_cyclic() will attempt
 275  * to shut itself off at each threshold interval (sampling period for calls
 276  * to the DDI lbolt routines), and return to the event driven mode, but will
 277  * be prevented from doing so if lbolt_cyclic_driven() is being heavily used.
 278  *
 279  * lbolt_bootstrap is used during boot to serve lbolt consumers who don't wait
 280  * for the cyclic subsystem to be intialized.
 281  *
 282  */
 283 int64_t lbolt_bootstrap(void);
 284 int64_t lbolt_event_driven(void);
 285 int64_t lbolt_cyclic_driven(void);
 286 int64_t (*lbolt_hybrid)(void) = lbolt_bootstrap;
 287 uint_t lbolt_ev_to_cyclic(caddr_t, caddr_t);
 288 
 289 /*
 290  * lbolt's cyclic, installed by clock_init().
 291  */
 292 static void lbolt_cyclic(void);
 293 
 294 /*
 295  * Tunable to keep lbolt in cyclic driven mode. This will prevent the system
 296  * from switching back to event driven, once it reaches cyclic mode.
 297  */
 298 static boolean_t lbolt_cyc_only = B_FALSE;
 299 
 300 /*
 301  * Cache aligned, per CPU structure with lbolt usage statistics.
 302  */
 303 static lbolt_cpu_t *lb_cpu;
 304 
 305 /*
 306  * Single, cache aligned, structure with all the information required by
 307  * the lbolt implementation.
 308  */
 309 lbolt_info_t *lb_info;
 310 
 311 
 312 int one_sec = 1; /* turned on once every second */
 313 static int fsflushcnt;  /* counter for t_fsflushr */
 314 int     dosynctodr = 1; /* patchable; enable/disable sync to TOD chip */
 315 int     tod_needsync = 0;       /* need to sync tod chip with software time */
 316 static int tod_broken = 0;      /* clock chip doesn't work */
 317 time_t  boot_time = 0;          /* Boot time in seconds since 1970 */
 318 hrtime_t boot_hrtime = 0;       /* gethrtime() at boot */
 319 cyclic_id_t clock_cyclic;       /* clock()'s cyclic_id */
 320 cyclic_id_t deadman_cyclic;     /* deadman()'s cyclic_id */
 321 
 322 extern void     clock_tick_schedule(int);
 323 
 324 static int lgrp_ticks;          /* counter to schedule lgrp load calcs */
 325 
 326 /*
 327  * for tod fault detection
 328  */
 329 #define TOD_REF_FREQ            ((longlong_t)(NANOSEC))
 330 #define TOD_STALL_THRESHOLD     (TOD_REF_FREQ * 3 / 2)
 331 #define TOD_JUMP_THRESHOLD      (TOD_REF_FREQ / 2)
 332 #define TOD_FILTER_N            4
 333 #define TOD_FILTER_SETTLE       (4 * TOD_FILTER_N)
 334 static enum tod_fault_type tod_faulted = TOD_NOFAULT;
 335 
 336 static int tod_status_flag = 0;         /* used by tod_validate() */
 337 
 338 static hrtime_t prev_set_tick = 0;      /* gethrtime() prior to tod_set() */
 339 static time_t prev_set_tod = 0;         /* tv_sec value passed to tod_set() */
 340 
 341 /* patchable via /etc/system */
 342 int tod_validate_enable = 1;
 343 
 344 /* Diagnose/Limit messages about delay(9F) called from interrupt context */
 345 int                     delay_from_interrupt_diagnose = 0;
 346 volatile uint32_t       delay_from_interrupt_msg = 20;
 347 
 348 /*
 349  * On non-SPARC systems, TOD validation must be deferred until gethrtime
 350  * returns non-zero values (after mach_clkinit's execution).
 351  * On SPARC systems, it must be deferred until after hrtime_base
 352  * and hres_last_tick are set (in the first invocation of hres_tick).
 353  * Since in both cases the prerequisites occur before the invocation of
 354  * tod_get() in clock(), the deferment is lifted there.
 355  */
 356 static boolean_t tod_validate_deferred = B_TRUE;
 357 
 358 /*
 359  * tod_fault_table[] must be aligned with
 360  * enum tod_fault_type in systm.h
 361  */
 362 static char *tod_fault_table[] = {
 363         "Reversed",                     /* TOD_REVERSED */
 364         "Stalled",                      /* TOD_STALLED */
 365         "Jumped",                       /* TOD_JUMPED */
 366         "Changed in Clock Rate",        /* TOD_RATECHANGED */
 367         "Is Read-Only"                  /* TOD_RDONLY */
 368         /*
 369          * no strings needed for TOD_NOFAULT
 370          */
 371 };
 372 
 373 /*
 374  * test hook for tod broken detection in tod_validate
 375  */
 376 int tod_unit_test = 0;
 377 time_t tod_test_injector;
 378 
 379 #define CLOCK_ADJ_HIST_SIZE     4
 380 
 381 static int      adj_hist_entry;
 382 
 383 int64_t clock_adj_hist[CLOCK_ADJ_HIST_SIZE];
 384 
 385 static void calcloadavg(int, uint64_t *);
 386 static int genloadavg(struct loadavg_s *);
 387 static void loadavg_update();
 388 
 389 void (*cmm_clock_callout)() = NULL;
 390 void (*cpucaps_clock_callout)() = NULL;
 391 
 392 extern clock_t clock_tick_proc_max;
 393 
 394 static int64_t deadman_counter = 0;
 395 
 396 static void
 397 clock(void)
 398 {
 399         kthread_t       *t;
 400         uint_t  nrunnable;
 401         uint_t  w_io;
 402         cpu_t   *cp;
 403         cpupart_t *cpupart;
 404         extern  void    set_freemem();
 405         void    (*funcp)();
 406         int32_t ltemp;
 407         int64_t lltemp;
 408         int s;
 409         int do_lgrp_load;
 410         int i;
 411         clock_t now = LBOLT_NO_ACCOUNT; /* current tick */
 412 
 413         if (panicstr)
 414                 return;
 415 
 416         /*
 417          * Make sure that 'freemem' do not drift too far from the truth
 418          */
 419         set_freemem();
 420 
 421 
 422         /*
 423          * Before the section which is repeated is executed, we do
 424          * the time delta processing which occurs every clock tick
 425          *
 426          * There is additional processing which happens every time
 427          * the nanosecond counter rolls over which is described
 428          * below - see the section which begins with : if (one_sec)
 429          *
 430          * This section marks the beginning of the precision-kernel
 431          * code fragment.
 432          *
 433          * First, compute the phase adjustment. If the low-order bits
 434          * (time_phase) of the update overflow, bump the higher order
 435          * bits (time_update).
 436          */
 437         time_phase += time_adj;
 438         if (time_phase <= -FINEUSEC) {
 439                 ltemp = -time_phase / SCALE_PHASE;
 440                 time_phase += ltemp * SCALE_PHASE;
 441                 s = hr_clock_lock();
 442                 timedelta -= ltemp * (NANOSEC/MICROSEC);
 443                 hr_clock_unlock(s);
 444         } else if (time_phase >= FINEUSEC) {
 445                 ltemp = time_phase / SCALE_PHASE;
 446                 time_phase -= ltemp * SCALE_PHASE;
 447                 s = hr_clock_lock();
 448                 timedelta += ltemp * (NANOSEC/MICROSEC);
 449                 hr_clock_unlock(s);
 450         }
 451 
 452         /*
 453          * End of precision-kernel code fragment which is processed
 454          * every timer interrupt.
 455          *
 456          * Continue with the interrupt processing as scheduled.
 457          */
 458         /*
 459          * Count the number of runnable threads and the number waiting
 460          * for some form of I/O to complete -- gets added to
 461          * sysinfo.waiting.  To know the state of the system, must add
 462          * wait counts from all CPUs.  Also add up the per-partition
 463          * statistics.
 464          */
 465         w_io = 0;
 466         nrunnable = 0;
 467 
 468         /*
 469          * keep track of when to update lgrp/part loads
 470          */
 471 
 472         do_lgrp_load = 0;
 473         if (lgrp_ticks++ >= hz / 10) {
 474                 lgrp_ticks = 0;
 475                 do_lgrp_load = 1;
 476         }
 477 
 478         if (one_sec) {
 479                 loadavg_update();
 480                 deadman_counter++;
 481         }
 482 
 483         /*
 484          * First count the threads waiting on kpreempt queues in each
 485          * CPU partition.
 486          */
 487 
 488         cpupart = cp_list_head;
 489         do {
 490                 uint_t cpupart_nrunnable = cpupart->cp_kp_queue.disp_nrunnable;
 491 
 492                 cpupart->cp_updates++;
 493                 nrunnable += cpupart_nrunnable;
 494                 cpupart->cp_nrunnable_cum += cpupart_nrunnable;
 495                 if (one_sec) {
 496                         cpupart->cp_nrunning = 0;
 497                         cpupart->cp_nrunnable = cpupart_nrunnable;
 498                 }
 499         } while ((cpupart = cpupart->cp_next) != cp_list_head);
 500 
 501 
 502         /* Now count the per-CPU statistics. */
 503         cp = cpu_list;
 504         do {
 505                 uint_t cpu_nrunnable = cp->cpu_disp->disp_nrunnable;
 506 
 507                 nrunnable += cpu_nrunnable;
 508                 cpupart = cp->cpu_part;
 509                 cpupart->cp_nrunnable_cum += cpu_nrunnable;
 510                 if (one_sec) {
 511                         cpupart->cp_nrunnable += cpu_nrunnable;
 512                         /*
 513                          * Update user, system, and idle cpu times.
 514                          */
 515                         cpupart->cp_nrunning++;
 516                         /*
 517                          * w_io is used to update sysinfo.waiting during
 518                          * one_second processing below.  Only gather w_io
 519                          * information when we walk the list of cpus if we're
 520                          * going to perform one_second processing.
 521                          */
 522                         w_io += CPU_STATS(cp, sys.iowait);
 523                 }
 524 
 525                 if (one_sec && (cp->cpu_flags & CPU_EXISTS)) {
 526                         int i, load, change;
 527                         hrtime_t intracct, intrused;
 528                         const hrtime_t maxnsec = 1000000000;
 529                         const int precision = 100;
 530 
 531                         /*
 532                          * Estimate interrupt load on this cpu each second.
 533                          * Computes cpu_intrload as %utilization (0-99).
 534                          */
 535 
 536                         /* add up interrupt time from all micro states */
 537                         for (intracct = 0, i = 0; i < NCMSTATES; i++)
 538                                 intracct += cp->cpu_intracct[i];
 539                         scalehrtime(&intracct);
 540 
 541                         /* compute nsec used in the past second */
 542                         intrused = intracct - cp->cpu_intrlast;
 543                         cp->cpu_intrlast = intracct;
 544 
 545                         /* limit the value for safety (and the first pass) */
 546                         if (intrused >= maxnsec)
 547                                 intrused = maxnsec - 1;
 548 
 549                         /* calculate %time in interrupt */
 550                         load = (precision * intrused) / maxnsec;
 551                         ASSERT(load >= 0 && load < precision);
 552                         change = cp->cpu_intrload - load;
 553 
 554                         /* jump to new max, or decay the old max */
 555                         if (change < 0)
 556                                 cp->cpu_intrload = load;
 557                         else if (change > 0)
 558                                 cp->cpu_intrload -= (change + 3) / 4;
 559 
 560                         DTRACE_PROBE3(cpu_intrload,
 561                             cpu_t *, cp,
 562                             hrtime_t, intracct,
 563                             hrtime_t, intrused);
 564                 }
 565 
 566                 if (do_lgrp_load &&
 567                     (cp->cpu_flags & CPU_EXISTS)) {
 568                         /*
 569                          * When updating the lgroup's load average,
 570                          * account for the thread running on the CPU.
 571                          * If the CPU is the current one, then we need
 572                          * to account for the underlying thread which
 573                          * got the clock interrupt not the thread that is
 574                          * handling the interrupt and caculating the load
 575                          * average
 576                          */
 577                         t = cp->cpu_thread;
 578                         if (CPU == cp)
 579                                 t = t->t_intr;
 580 
 581                         /*
 582                          * Account for the load average for this thread if
 583                          * it isn't the idle thread or it is on the interrupt
 584                          * stack and not the current CPU handling the clock
 585                          * interrupt
 586                          */
 587                         if ((t && t != cp->cpu_idle_thread) || (CPU != cp &&
 588                             CPU_ON_INTR(cp))) {
 589                                 if (t->t_lpl == cp->cpu_lpl) {
 590                                         /* local thread */
 591                                         cpu_nrunnable++;
 592                                 } else {
 593                                         /*
 594                                          * This is a remote thread, charge it
 595                                          * against its home lgroup.  Note that
 596                                          * we notice that a thread is remote
 597                                          * only if it's currently executing.
 598                                          * This is a reasonable approximation,
 599                                          * since queued remote threads are rare.
 600                                          * Note also that if we didn't charge
 601                                          * it to its home lgroup, remote
 602                                          * execution would often make a system
 603                                          * appear balanced even though it was
 604                                          * not, and thread placement/migration
 605                                          * would often not be done correctly.
 606                                          */
 607                                         lgrp_loadavg(t->t_lpl,
 608                                             LGRP_LOADAVG_IN_THREAD_MAX, 0);
 609                                 }
 610                         }
 611                         lgrp_loadavg(cp->cpu_lpl,
 612                             cpu_nrunnable * LGRP_LOADAVG_IN_THREAD_MAX, 1);
 613                 }
 614         } while ((cp = cp->cpu_next) != cpu_list);
 615 
 616         clock_tick_schedule(one_sec);
 617 
 618         /*
 619          * Check for a callout that needs be called from the clock
 620          * thread to support the membership protocol in a clustered
 621          * system.  Copy the function pointer so that we can reset
 622          * this to NULL if needed.
 623          */
 624         if ((funcp = cmm_clock_callout) != NULL)
 625                 (*funcp)();
 626 
 627         if ((funcp = cpucaps_clock_callout) != NULL)
 628                 (*funcp)();
 629 
 630         /*
 631          * Wakeup the cageout thread waiters once per second.
 632          */
 633         if (one_sec)
 634                 kcage_tick();
 635 
 636         if (one_sec) {
 637 
 638                 int drift, absdrift;
 639                 timestruc_t tod;
 640                 int s;
 641 
 642                 /*
 643                  * Beginning of precision-kernel code fragment executed
 644                  * every second.
 645                  *
 646                  * On rollover of the second the phase adjustment to be
 647                  * used for the next second is calculated.  Also, the
 648                  * maximum error is increased by the tolerance.  If the
 649                  * PPS frequency discipline code is present, the phase is
 650                  * increased to compensate for the CPU clock oscillator
 651                  * frequency error.
 652                  *
 653                  * On a 32-bit machine and given parameters in the timex.h
 654                  * header file, the maximum phase adjustment is +-512 ms
 655                  * and maximum frequency offset is (a tad less than)
 656                  * +-512 ppm. On a 64-bit machine, you shouldn't need to ask.
 657                  */
 658                 time_maxerror += time_tolerance / SCALE_USEC;
 659 
 660                 /*
 661                  * Leap second processing. If in leap-insert state at
 662                  * the end of the day, the system clock is set back one
 663                  * second; if in leap-delete state, the system clock is
 664                  * set ahead one second. The microtime() routine or
 665                  * external clock driver will insure that reported time
 666                  * is always monotonic. The ugly divides should be
 667                  * replaced.
 668                  */
 669                 switch (time_state) {
 670 
 671                 case TIME_OK:
 672                         if (time_status & STA_INS)
 673                                 time_state = TIME_INS;
 674                         else if (time_status & STA_DEL)
 675                                 time_state = TIME_DEL;
 676                         break;
 677 
 678                 case TIME_INS:
 679                         if (hrestime.tv_sec % 86400 == 0) {
 680                                 s = hr_clock_lock();
 681                                 hrestime.tv_sec--;
 682                                 hr_clock_unlock(s);
 683                                 time_state = TIME_OOP;
 684                         }
 685                         break;
 686 
 687                 case TIME_DEL:
 688                         if ((hrestime.tv_sec + 1) % 86400 == 0) {
 689                                 s = hr_clock_lock();
 690                                 hrestime.tv_sec++;
 691                                 hr_clock_unlock(s);
 692                                 time_state = TIME_WAIT;
 693                         }
 694                         break;
 695 
 696                 case TIME_OOP:
 697                         time_state = TIME_WAIT;
 698                         break;
 699 
 700                 case TIME_WAIT:
 701                         if (!(time_status & (STA_INS | STA_DEL)))
 702                                 time_state = TIME_OK;
 703                 default:
 704                         break;
 705                 }
 706 
 707                 /*
 708                  * Compute the phase adjustment for the next second. In
 709                  * PLL mode, the offset is reduced by a fixed factor
 710                  * times the time constant. In FLL mode the offset is
 711                  * used directly. In either mode, the maximum phase
 712                  * adjustment for each second is clamped so as to spread
 713                  * the adjustment over not more than the number of
 714                  * seconds between updates.
 715                  */
 716                 if (time_offset == 0)
 717                         time_adj = 0;
 718                 else if (time_offset < 0) {
 719                         lltemp = -time_offset;
 720                         if (!(time_status & STA_FLL)) {
 721                                 if ((1 << time_constant) >= SCALE_KG)
 722                                         lltemp *= (1 << time_constant) /
 723                                             SCALE_KG;
 724                                 else
 725                                         lltemp = (lltemp / SCALE_KG) >>
 726                                             time_constant;
 727                         }
 728                         if (lltemp > (MAXPHASE / MINSEC) * SCALE_UPDATE)
 729                                 lltemp = (MAXPHASE / MINSEC) * SCALE_UPDATE;
 730                         time_offset += lltemp;
 731                         time_adj = -(lltemp * SCALE_PHASE) / hz / SCALE_UPDATE;
 732                 } else {
 733                         lltemp = time_offset;
 734                         if (!(time_status & STA_FLL)) {
 735                                 if ((1 << time_constant) >= SCALE_KG)
 736                                         lltemp *= (1 << time_constant) /
 737                                             SCALE_KG;
 738                                 else
 739                                         lltemp = (lltemp / SCALE_KG) >>
 740                                             time_constant;
 741                         }
 742                         if (lltemp > (MAXPHASE / MINSEC) * SCALE_UPDATE)
 743                                 lltemp = (MAXPHASE / MINSEC) * SCALE_UPDATE;
 744                         time_offset -= lltemp;
 745                         time_adj = (lltemp * SCALE_PHASE) / hz / SCALE_UPDATE;
 746                 }
 747 
 748                 /*
 749                  * Compute the frequency estimate and additional phase
 750                  * adjustment due to frequency error for the next
 751                  * second. When the PPS signal is engaged, gnaw on the
 752                  * watchdog counter and update the frequency computed by
 753                  * the pll and the PPS signal.
 754                  */
 755                 pps_valid++;
 756                 if (pps_valid == PPS_VALID) {
 757                         pps_jitter = MAXTIME;
 758                         pps_stabil = MAXFREQ;
 759                         time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER |
 760                             STA_PPSWANDER | STA_PPSERROR);
 761                 }
 762                 lltemp = time_freq + pps_freq;
 763 
 764                 if (lltemp)
 765                         time_adj += (lltemp * SCALE_PHASE) / (SCALE_USEC * hz);
 766 
 767                 /*
 768                  * End of precision kernel-code fragment
 769                  *
 770                  * The section below should be modified if we are planning
 771                  * to use NTP for synchronization.
 772                  *
 773                  * Note: the clock synchronization code now assumes
 774                  * the following:
 775                  *   - if dosynctodr is 1, then compute the drift between
 776                  *      the tod chip and software time and adjust one or
 777                  *      the other depending on the circumstances
 778                  *
 779                  *   - if dosynctodr is 0, then the tod chip is independent
 780                  *      of the software clock and should not be adjusted,
 781                  *      but allowed to free run.  this allows NTP to sync.
 782                  *      hrestime without any interference from the tod chip.
 783                  */
 784 
 785                 tod_validate_deferred = B_FALSE;
 786                 mutex_enter(&tod_lock);
 787                 tod = tod_get();
 788                 drift = tod.tv_sec - hrestime.tv_sec;
 789                 absdrift = (drift >= 0) ? drift : -drift;
 790                 if (tod_needsync || absdrift > 1) {
 791                         int s;
 792                         if (absdrift > 2) {
 793                                 if (!tod_broken && tod_faulted == TOD_NOFAULT) {
 794                                         s = hr_clock_lock();
 795                                         hrestime = tod;
 796                                         membar_enter(); /* hrestime visible */
 797                                         timedelta = 0;
 798                                         timechanged++;
 799                                         tod_needsync = 0;
 800                                         hr_clock_unlock(s);
 801                                         callout_hrestime();
 802 
 803                                 }
 804                         } else {
 805                                 if (tod_needsync || !dosynctodr) {
 806                                         gethrestime(&tod);
 807                                         tod_set(tod);
 808                                         s = hr_clock_lock();
 809                                         if (timedelta == 0)
 810                                                 tod_needsync = 0;
 811                                         hr_clock_unlock(s);
 812                                 } else {
 813                                         /*
 814                                          * If the drift is 2 seconds on the
 815                                          * money, then the TOD is adjusting
 816                                          * the clock;  record that.
 817                                          */
 818                                         clock_adj_hist[adj_hist_entry++ %
 819                                             CLOCK_ADJ_HIST_SIZE] = now;
 820                                         s = hr_clock_lock();
 821                                         timedelta = (int64_t)drift*NANOSEC;
 822                                         hr_clock_unlock(s);
 823                                 }
 824                         }
 825                 }
 826                 one_sec = 0;
 827                 time = gethrestime_sec();  /* for crusty old kmem readers */
 828                 mutex_exit(&tod_lock);
 829 
 830                 /*
 831                  * Some drivers still depend on this... XXX
 832                  */
 833                 cv_broadcast(&lbolt_cv);
 834 
 835                 vminfo.freemem += freemem;
 836                 {
 837                         pgcnt_t maxswap, resv, free;
 838                         pgcnt_t avail =
 839                             MAX((spgcnt_t)(availrmem - swapfs_minfree), 0);
 840 
 841                         maxswap = k_anoninfo.ani_mem_resv +
 842                             k_anoninfo.ani_max +avail;
 843                         /* Update ani_free */
 844                         set_anoninfo();
 845                         free = k_anoninfo.ani_free + avail;
 846                         resv = k_anoninfo.ani_phys_resv +
 847                             k_anoninfo.ani_mem_resv;
 848 
 849                         vminfo.swap_resv += resv;
 850                         /* number of reserved and allocated pages */
 851 #ifdef  DEBUG
 852                         if (maxswap < free)
 853                                 cmn_err(CE_WARN, "clock: maxswap < free");
 854                         if (maxswap < resv)
 855                                 cmn_err(CE_WARN, "clock: maxswap < resv");
 856 #endif
 857                         vminfo.swap_alloc += maxswap - free;
 858                         vminfo.swap_avail += maxswap - resv;
 859                         vminfo.swap_free += free;
 860                 }
 861                 vminfo.updates++;
 862                 if (nrunnable) {
 863                         sysinfo.runque += nrunnable;
 864                         sysinfo.runocc++;
 865                 }
 866                 if (nswapped) {
 867                         sysinfo.swpque += nswapped;
 868                         sysinfo.swpocc++;
 869                 }
 870                 sysinfo.waiting += w_io;
 871                 sysinfo.updates++;
 872 
 873                 /*
 874                  * Wake up fsflush to write out DELWRI
 875                  * buffers, dirty pages and other cached
 876                  * administrative data, e.g. inodes.
 877                  */
 878                 if (--fsflushcnt <= 0) {
 879                         fsflushcnt = tune.t_fsflushr;
 880                         cv_signal(&fsflush_cv);
 881                 }
 882 
 883                 vmmeter();
 884                 calcloadavg(genloadavg(&loadavg), hp_avenrun);
 885                 for (i = 0; i < 3; i++)
 886                         /*
 887                          * At the moment avenrun[] can only hold 31
 888                          * bits of load average as it is a signed
 889                          * int in the API. We need to ensure that
 890                          * hp_avenrun[i] >> (16 - FSHIFT) will not be
 891                          * too large. If it is, we put the largest value
 892                          * that we can use into avenrun[i]. This is
 893                          * kludgey, but about all we can do until we
 894                          * avenrun[] is declared as an array of uint64[]
 895                          */
 896                         if (hp_avenrun[i] < ((uint64_t)1<<(31+16-FSHIFT)))
 897                                 avenrun[i] = (int32_t)(hp_avenrun[i] >>
 898                                     (16 - FSHIFT));
 899                         else
 900                                 avenrun[i] = 0x7fffffff;
 901 
 902                 cpupart = cp_list_head;
 903                 do {
 904                         calcloadavg(genloadavg(&cpupart->cp_loadavg),
 905                             cpupart->cp_hp_avenrun);
 906                 } while ((cpupart = cpupart->cp_next) != cp_list_head);
 907 
 908                 /*
 909                  * Wake up the swapper thread if necessary.
 910                  */
 911                 if (runin ||
 912                     (runout && (avefree < desfree || wake_sched_sec))) {
 913                         t = &t0;
 914                         thread_lock(t);
 915                         if (t->t_state == TS_STOPPED) {
 916                                 runin = runout = 0;
 917                                 wake_sched_sec = 0;
 918                                 t->t_whystop = 0;
 919                                 t->t_whatstop = 0;
 920                                 t->t_schedflag &= ~TS_ALLSTART;
 921                                 THREAD_TRANSITION(t);
 922                                 setfrontdq(t);
 923                         }
 924                         thread_unlock(t);
 925                 }
 926         }
 927 
 928         /*
 929          * Wake up the swapper if any high priority swapped-out threads
 930          * became runable during the last tick.
 931          */
 932         if (wake_sched) {
 933                 t = &t0;
 934                 thread_lock(t);
 935                 if (t->t_state == TS_STOPPED) {
 936                         runin = runout = 0;
 937                         wake_sched = 0;
 938                         t->t_whystop = 0;
 939                         t->t_whatstop = 0;
 940                         t->t_schedflag &= ~TS_ALLSTART;
 941                         THREAD_TRANSITION(t);
 942                         setfrontdq(t);
 943                 }
 944                 thread_unlock(t);
 945         }
 946 }
 947 
 948 void
 949 clock_init(void)
 950 {
 951         cyc_handler_t clk_hdlr, lbolt_hdlr;
 952         cyc_time_t clk_when, lbolt_when;
 953         int i, sz;
 954         intptr_t buf;
 955 
 956         /*
 957          * Setup handler and timer for the clock cyclic.
 958          */
 959         clk_hdlr.cyh_func = (cyc_func_t)clock;
 960         clk_hdlr.cyh_level = CY_LOCK_LEVEL;
 961         clk_hdlr.cyh_arg = NULL;
 962 
 963         clk_when.cyt_when = 0;
 964         clk_when.cyt_interval = nsec_per_tick;
 965 
 966         /*
 967          * The lbolt cyclic will be reprogramed to fire at a nsec_per_tick
 968          * interval to satisfy performance needs of the DDI lbolt consumers.
 969          * It is off by default.
 970          */
 971         lbolt_hdlr.cyh_func = (cyc_func_t)lbolt_cyclic;
 972         lbolt_hdlr.cyh_level = CY_LOCK_LEVEL;
 973         lbolt_hdlr.cyh_arg = NULL;
 974 
 975         lbolt_when.cyt_interval = nsec_per_tick;
 976 
 977         /*
 978          * Allocate cache line aligned space for the per CPU lbolt data and
 979          * lbolt info structures, and initialize them with their default
 980          * values. Note that these structures are also cache line sized.
 981          */
 982         sz = sizeof (lbolt_info_t) + CPU_CACHE_COHERENCE_SIZE;
 983         buf = (intptr_t)kmem_zalloc(sz, KM_SLEEP);
 984         lb_info = (lbolt_info_t *)P2ROUNDUP(buf, CPU_CACHE_COHERENCE_SIZE);
 985 
 986         if (hz != HZ_DEFAULT)
 987                 lb_info->lbi_thresh_interval = LBOLT_THRESH_INTERVAL *
 988                     hz/HZ_DEFAULT;
 989         else
 990                 lb_info->lbi_thresh_interval = LBOLT_THRESH_INTERVAL;
 991 
 992         lb_info->lbi_thresh_calls = LBOLT_THRESH_CALLS;
 993 
 994         sz = (sizeof (lbolt_cpu_t) * max_ncpus) + CPU_CACHE_COHERENCE_SIZE;
 995         buf = (intptr_t)kmem_zalloc(sz, KM_SLEEP);
 996         lb_cpu = (lbolt_cpu_t *)P2ROUNDUP(buf, CPU_CACHE_COHERENCE_SIZE);
 997 
 998         for (i = 0; i < max_ncpus; i++)
 999                 lb_cpu[i].lbc_counter = lb_info->lbi_thresh_calls;
1000 
1001         /*
1002          * Install the softint used to switch between event and cyclic driven
1003          * lbolt. We use a soft interrupt to make sure the context of the
1004          * cyclic reprogram call is safe.
1005          */
1006         lbolt_softint_add();
1007 
1008         /*
1009          * Since the hybrid lbolt implementation is based on a hardware counter
1010          * that is reset at every hardware reboot and that we'd like to have
1011          * the lbolt value starting at zero after both a hardware and a fast
1012          * reboot, we calculate the number of clock ticks the system's been up
1013          * and store it in the lbi_debug_time field of the lbolt info structure.
1014          * The value of this field will be subtracted from lbolt before
1015          * returning it.
1016          */
1017         lb_info->lbi_internal = lb_info->lbi_debug_time =
1018             (gethrtime()/nsec_per_tick);
1019 
1020         /*
1021          * lbolt_hybrid points at lbolt_bootstrap until now. The LBOLT_* macros
1022          * and lbolt_debug_{enter,return} use this value as an indication that
1023          * the initializaion above hasn't been completed. Setting lbolt_hybrid
1024          * to either lbolt_{cyclic,event}_driven here signals those code paths
1025          * that the lbolt related structures can be used.
1026          */
1027         if (lbolt_cyc_only) {
1028                 lbolt_when.cyt_when = 0;
1029                 lbolt_hybrid = lbolt_cyclic_driven;
1030         } else {
1031                 lbolt_when.cyt_when = CY_INFINITY;
1032                 lbolt_hybrid = lbolt_event_driven;
1033         }
1034 
1035         /*
1036          * Grab cpu_lock and install all three cyclics.
1037          */
1038         mutex_enter(&cpu_lock);
1039 
1040         clock_cyclic = cyclic_add(&clk_hdlr, &clk_when);
1041         lb_info->id.lbi_cyclic_id = cyclic_add(&lbolt_hdlr, &lbolt_when);
1042 
1043         mutex_exit(&cpu_lock);
1044 }
1045 
1046 /*
1047  * Called before calcloadavg to get 10-sec moving loadavg together
1048  */
1049 
1050 static int
1051 genloadavg(struct loadavg_s *avgs)
1052 {
1053         int avg;
1054         int spos; /* starting position */
1055         int cpos; /* moving current position */
1056         int i;
1057         int slen;
1058         hrtime_t hr_avg;
1059 
1060         /* 10-second snapshot, calculate first positon */
1061         if (avgs->lg_len == 0) {
1062                 return (0);
1063         }
1064         slen = avgs->lg_len < S_MOVAVG_SZ ? avgs->lg_len : S_MOVAVG_SZ;
1065 
1066         spos = (avgs->lg_cur - 1) >= 0 ? avgs->lg_cur - 1 :
1067             S_LOADAVG_SZ + (avgs->lg_cur - 1);
1068         for (i = hr_avg = 0; i < slen; i++) {
1069                 cpos = (spos - i) >= 0 ? spos - i : S_LOADAVG_SZ + (spos - i);
1070                 hr_avg += avgs->lg_loads[cpos];
1071         }
1072 
1073         hr_avg = hr_avg / slen;
1074         avg = hr_avg / (NANOSEC / LGRP_LOADAVG_IN_THREAD_MAX);
1075 
1076         return (avg);
1077 }
1078 
1079 /*
1080  * Run every second from clock () to update the loadavg count available to the
1081  * system and cpu-partitions.
1082  *
1083  * This works by sampling the previous usr, sys, wait time elapsed,
1084  * computing a delta, and adding that delta to the elapsed usr, sys,
1085  * wait increase.
1086  */
1087 
1088 static void
1089 loadavg_update()
1090 {
1091         cpu_t *cp;
1092         cpupart_t *cpupart;
1093         hrtime_t cpu_total;
1094         int prev;
1095 
1096         cp = cpu_list;
1097         loadavg.lg_total = 0;
1098 
1099         /*
1100          * first pass totals up per-cpu statistics for system and cpu
1101          * partitions
1102          */
1103 
1104         do {
1105                 struct loadavg_s *lavg;
1106 
1107                 lavg = &cp->cpu_loadavg;
1108 
1109                 cpu_total = cp->cpu_acct[CMS_USER] +
1110                     cp->cpu_acct[CMS_SYSTEM] + cp->cpu_waitrq;
1111                 /* compute delta against last total */
1112                 scalehrtime(&cpu_total);
1113                 prev = (lavg->lg_cur - 1) >= 0 ? lavg->lg_cur - 1 :
1114                     S_LOADAVG_SZ + (lavg->lg_cur - 1);
1115                 if (lavg->lg_loads[prev] <= 0) {
1116                         lavg->lg_loads[lavg->lg_cur] = cpu_total;
1117                         cpu_total = 0;
1118                 } else {
1119                         lavg->lg_loads[lavg->lg_cur] = cpu_total;
1120                         cpu_total = cpu_total - lavg->lg_loads[prev];
1121                         if (cpu_total < 0)
1122                                 cpu_total = 0;
1123                 }
1124 
1125                 lavg->lg_cur = (lavg->lg_cur + 1) % S_LOADAVG_SZ;
1126                 lavg->lg_len = (lavg->lg_len + 1) < S_LOADAVG_SZ ?
1127                     lavg->lg_len + 1 : S_LOADAVG_SZ;
1128 
1129                 loadavg.lg_total += cpu_total;
1130                 cp->cpu_part->cp_loadavg.lg_total += cpu_total;
1131 
1132         } while ((cp = cp->cpu_next) != cpu_list);
1133 
1134         loadavg.lg_loads[loadavg.lg_cur] = loadavg.lg_total;
1135         loadavg.lg_cur = (loadavg.lg_cur + 1) % S_LOADAVG_SZ;
1136         loadavg.lg_len = (loadavg.lg_len + 1) < S_LOADAVG_SZ ?
1137             loadavg.lg_len + 1 : S_LOADAVG_SZ;
1138         /*
1139          * Second pass updates counts
1140          */
1141         cpupart = cp_list_head;
1142 
1143         do {
1144                 struct loadavg_s *lavg;
1145 
1146                 lavg = &cpupart->cp_loadavg;
1147                 lavg->lg_loads[lavg->lg_cur] = lavg->lg_total;
1148                 lavg->lg_total = 0;
1149                 lavg->lg_cur = (lavg->lg_cur + 1) % S_LOADAVG_SZ;
1150                 lavg->lg_len = (lavg->lg_len + 1) < S_LOADAVG_SZ ?
1151                     lavg->lg_len + 1 : S_LOADAVG_SZ;
1152 
1153         } while ((cpupart = cpupart->cp_next) != cp_list_head);
1154 
1155         /*
1156          * Third pass totals up per-zone statistics.
1157          */
1158         zone_loadavg_update();
1159 }
1160 
1161 /*
1162  * clock_update() - local clock update
1163  *
1164  * This routine is called by ntp_adjtime() to update the local clock
1165  * phase and frequency. The implementation is of an
1166  * adaptive-parameter, hybrid phase/frequency-lock loop (PLL/FLL). The
1167  * routine computes new time and frequency offset estimates for each
1168  * call.  The PPS signal itself determines the new time offset,
1169  * instead of the calling argument.  Presumably, calls to
1170  * ntp_adjtime() occur only when the caller believes the local clock
1171  * is valid within some bound (+-128 ms with NTP). If the caller's
1172  * time is far different than the PPS time, an argument will ensue,
1173  * and it's not clear who will lose.
1174  *
1175  * For uncompensated quartz crystal oscillatores and nominal update
1176  * intervals less than 1024 s, operation should be in phase-lock mode
1177  * (STA_FLL = 0), where the loop is disciplined to phase. For update
1178  * intervals greater than this, operation should be in frequency-lock
1179  * mode (STA_FLL = 1), where the loop is disciplined to frequency.
1180  *
1181  * Note: mutex(&tod_lock) is in effect.
1182  */
1183 void
1184 clock_update(int offset)
1185 {
1186         int ltemp, mtemp, s;
1187 
1188         ASSERT(MUTEX_HELD(&tod_lock));
1189 
1190         if (!(time_status & STA_PLL) && !(time_status & STA_PPSTIME))
1191                 return;
1192         ltemp = offset;
1193         if ((time_status & STA_PPSTIME) && (time_status & STA_PPSSIGNAL))
1194                 ltemp = pps_offset;
1195 
1196         /*
1197          * Scale the phase adjustment and clamp to the operating range.
1198          */
1199         if (ltemp > MAXPHASE)
1200                 time_offset = MAXPHASE * SCALE_UPDATE;
1201         else if (ltemp < -MAXPHASE)
1202                 time_offset = -(MAXPHASE * SCALE_UPDATE);
1203         else
1204                 time_offset = ltemp * SCALE_UPDATE;
1205 
1206         /*
1207          * Select whether the frequency is to be controlled and in which
1208          * mode (PLL or FLL). Clamp to the operating range. Ugly
1209          * multiply/divide should be replaced someday.
1210          */
1211         if (time_status & STA_FREQHOLD || time_reftime == 0)
1212                 time_reftime = hrestime.tv_sec;
1213 
1214         mtemp = hrestime.tv_sec - time_reftime;
1215         time_reftime = hrestime.tv_sec;
1216 
1217         if (time_status & STA_FLL) {
1218                 if (mtemp >= MINSEC) {
1219                         ltemp = ((time_offset / mtemp) * (SCALE_USEC /
1220                             SCALE_UPDATE));
1221                         if (ltemp)
1222                                 time_freq += ltemp / SCALE_KH;
1223                 }
1224         } else {
1225                 if (mtemp < MAXSEC) {
1226                         ltemp *= mtemp;
1227                         if (ltemp)
1228                                 time_freq += (int)(((int64_t)ltemp *
1229                                     SCALE_USEC) / SCALE_KF)
1230                                     / (1 << (time_constant * 2));
1231                 }
1232         }
1233         if (time_freq > time_tolerance)
1234                 time_freq = time_tolerance;
1235         else if (time_freq < -time_tolerance)
1236                 time_freq = -time_tolerance;
1237 
1238         s = hr_clock_lock();
1239         tod_needsync = 1;
1240         hr_clock_unlock(s);
1241 }
1242 
1243 /*
1244  * ddi_hardpps() - discipline CPU clock oscillator to external PPS signal
1245  *
1246  * This routine is called at each PPS interrupt in order to discipline
1247  * the CPU clock oscillator to the PPS signal. It measures the PPS phase
1248  * and leaves it in a handy spot for the clock() routine. It
1249  * integrates successive PPS phase differences and calculates the
1250  * frequency offset. This is used in clock() to discipline the CPU
1251  * clock oscillator so that intrinsic frequency error is cancelled out.
1252  * The code requires the caller to capture the time and hardware counter
1253  * value at the on-time PPS signal transition.
1254  *
1255  * Note that, on some Unix systems, this routine runs at an interrupt
1256  * priority level higher than the timer interrupt routine clock().
1257  * Therefore, the variables used are distinct from the clock()
1258  * variables, except for certain exceptions: The PPS frequency pps_freq
1259  * and phase pps_offset variables are determined by this routine and
1260  * updated atomically. The time_tolerance variable can be considered a
1261  * constant, since it is infrequently changed, and then only when the
1262  * PPS signal is disabled. The watchdog counter pps_valid is updated
1263  * once per second by clock() and is atomically cleared in this
1264  * routine.
1265  *
1266  * tvp is the time of the last tick; usec is a microsecond count since the
1267  * last tick.
1268  *
1269  * Note: In Solaris systems, the tick value is actually given by
1270  *       usec_per_tick.  This is called from the serial driver cdintr(),
1271  *       or equivalent, at a high PIL.  Because the kernel keeps a
1272  *       highresolution time, the following code can accept either
1273  *       the traditional argument pair, or the current highres timestamp
1274  *       in tvp and zero in usec.
1275  */
1276 void
1277 ddi_hardpps(struct timeval *tvp, int usec)
1278 {
1279         int u_usec, v_usec, bigtick;
1280         time_t cal_sec;
1281         int cal_usec;
1282 
1283         /*
1284          * An occasional glitch can be produced when the PPS interrupt
1285          * occurs in the clock() routine before the time variable is
1286          * updated. Here the offset is discarded when the difference
1287          * between it and the last one is greater than tick/2, but not
1288          * if the interval since the first discard exceeds 30 s.
1289          */
1290         time_status |= STA_PPSSIGNAL;
1291         time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR);
1292         pps_valid = 0;
1293         u_usec = -tvp->tv_usec;
1294         if (u_usec < -(MICROSEC/2))
1295                 u_usec += MICROSEC;
1296         v_usec = pps_offset - u_usec;
1297         if (v_usec < 0)
1298                 v_usec = -v_usec;
1299         if (v_usec > (usec_per_tick >> 1)) {
1300                 if (pps_glitch > MAXGLITCH) {
1301                         pps_glitch = 0;
1302                         pps_tf[2] = u_usec;
1303                         pps_tf[1] = u_usec;
1304                 } else {
1305                         pps_glitch++;
1306                         u_usec = pps_offset;
1307                 }
1308         } else
1309                 pps_glitch = 0;
1310 
1311         /*
1312          * A three-stage median filter is used to help deglitch the pps
1313          * time. The median sample becomes the time offset estimate; the
1314          * difference between the other two samples becomes the time
1315          * dispersion (jitter) estimate.
1316          */
1317         pps_tf[2] = pps_tf[1];
1318         pps_tf[1] = pps_tf[0];
1319         pps_tf[0] = u_usec;
1320         if (pps_tf[0] > pps_tf[1]) {
1321                 if (pps_tf[1] > pps_tf[2]) {
1322                         pps_offset = pps_tf[1];         /* 0 1 2 */
1323                         v_usec = pps_tf[0] - pps_tf[2];
1324                 } else if (pps_tf[2] > pps_tf[0]) {
1325                         pps_offset = pps_tf[0];         /* 2 0 1 */
1326                         v_usec = pps_tf[2] - pps_tf[1];
1327                 } else {
1328                         pps_offset = pps_tf[2];         /* 0 2 1 */
1329                         v_usec = pps_tf[0] - pps_tf[1];
1330                 }
1331         } else {
1332                 if (pps_tf[1] < pps_tf[2]) {
1333                         pps_offset = pps_tf[1];         /* 2 1 0 */
1334                         v_usec = pps_tf[2] - pps_tf[0];
1335                 } else  if (pps_tf[2] < pps_tf[0]) {
1336                         pps_offset = pps_tf[0];         /* 1 0 2 */
1337                         v_usec = pps_tf[1] - pps_tf[2];
1338                 } else {
1339                         pps_offset = pps_tf[2];         /* 1 2 0 */
1340                         v_usec = pps_tf[1] - pps_tf[0];
1341                 }
1342         }
1343         if (v_usec > MAXTIME)
1344                 pps_jitcnt++;
1345         v_usec = (v_usec << PPS_AVG) - pps_jitter;
1346         pps_jitter += v_usec / (1 << PPS_AVG);
1347         if (pps_jitter > (MAXTIME >> 1))
1348                 time_status |= STA_PPSJITTER;
1349 
1350         /*
1351          * During the calibration interval adjust the starting time when
1352          * the tick overflows. At the end of the interval compute the
1353          * duration of the interval and the difference of the hardware
1354          * counters at the beginning and end of the interval. This code
1355          * is deliciously complicated by the fact valid differences may
1356          * exceed the value of tick when using long calibration
1357          * intervals and small ticks. Note that the counter can be
1358          * greater than tick if caught at just the wrong instant, but
1359          * the values returned and used here are correct.
1360          */
1361         bigtick = (int)usec_per_tick * SCALE_USEC;
1362         pps_usec -= pps_freq;
1363         if (pps_usec >= bigtick)
1364                 pps_usec -= bigtick;
1365         if (pps_usec < 0)
1366                 pps_usec += bigtick;
1367         pps_time.tv_sec++;
1368         pps_count++;
1369         if (pps_count < (1 << pps_shift))
1370                 return;
1371         pps_count = 0;
1372         pps_calcnt++;
1373         u_usec = usec * SCALE_USEC;
1374         v_usec = pps_usec - u_usec;
1375         if (v_usec >= bigtick >> 1)
1376                 v_usec -= bigtick;
1377         if (v_usec < -(bigtick >> 1))
1378                 v_usec += bigtick;
1379         if (v_usec < 0)
1380                 v_usec = -(-v_usec >> pps_shift);
1381         else
1382                 v_usec = v_usec >> pps_shift;
1383         pps_usec = u_usec;
1384         cal_sec = tvp->tv_sec;
1385         cal_usec = tvp->tv_usec;
1386         cal_sec -= pps_time.tv_sec;
1387         cal_usec -= pps_time.tv_usec;
1388         if (cal_usec < 0) {
1389                 cal_usec += MICROSEC;
1390                 cal_sec--;
1391         }
1392         pps_time = *tvp;
1393 
1394         /*
1395          * Check for lost interrupts, noise, excessive jitter and
1396          * excessive frequency error. The number of timer ticks during
1397          * the interval may vary +-1 tick. Add to this a margin of one
1398          * tick for the PPS signal jitter and maximum frequency
1399          * deviation. If the limits are exceeded, the calibration
1400          * interval is reset to the minimum and we start over.
1401          */
1402         u_usec = (int)usec_per_tick << 1;
1403         if (!((cal_sec == -1 && cal_usec > (MICROSEC - u_usec)) ||
1404             (cal_sec == 0 && cal_usec < u_usec)) ||
1405             v_usec > time_tolerance || v_usec < -time_tolerance) {
1406                 pps_errcnt++;
1407                 pps_shift = PPS_SHIFT;
1408                 pps_intcnt = 0;
1409                 time_status |= STA_PPSERROR;
1410                 return;
1411         }
1412 
1413         /*
1414          * A three-stage median filter is used to help deglitch the pps
1415          * frequency. The median sample becomes the frequency offset
1416          * estimate; the difference between the other two samples
1417          * becomes the frequency dispersion (stability) estimate.
1418          */
1419         pps_ff[2] = pps_ff[1];
1420         pps_ff[1] = pps_ff[0];
1421         pps_ff[0] = v_usec;
1422         if (pps_ff[0] > pps_ff[1]) {
1423                 if (pps_ff[1] > pps_ff[2]) {
1424                         u_usec = pps_ff[1];             /* 0 1 2 */
1425                         v_usec = pps_ff[0] - pps_ff[2];
1426                 } else if (pps_ff[2] > pps_ff[0]) {
1427                         u_usec = pps_ff[0];             /* 2 0 1 */
1428                         v_usec = pps_ff[2] - pps_ff[1];
1429                 } else {
1430                         u_usec = pps_ff[2];             /* 0 2 1 */
1431                         v_usec = pps_ff[0] - pps_ff[1];
1432                 }
1433         } else {
1434                 if (pps_ff[1] < pps_ff[2]) {
1435                         u_usec = pps_ff[1];             /* 2 1 0 */
1436                         v_usec = pps_ff[2] - pps_ff[0];
1437                 } else  if (pps_ff[2] < pps_ff[0]) {
1438                         u_usec = pps_ff[0];             /* 1 0 2 */
1439                         v_usec = pps_ff[1] - pps_ff[2];
1440                 } else {
1441                         u_usec = pps_ff[2];             /* 1 2 0 */
1442                         v_usec = pps_ff[1] - pps_ff[0];
1443                 }
1444         }
1445 
1446         /*
1447          * Here the frequency dispersion (stability) is updated. If it
1448          * is less than one-fourth the maximum (MAXFREQ), the frequency
1449          * offset is updated as well, but clamped to the tolerance. It
1450          * will be processed later by the clock() routine.
1451          */
1452         v_usec = (v_usec >> 1) - pps_stabil;
1453         if (v_usec < 0)
1454                 pps_stabil -= -v_usec >> PPS_AVG;
1455         else
1456                 pps_stabil += v_usec >> PPS_AVG;
1457         if (pps_stabil > MAXFREQ >> 2) {
1458                 pps_stbcnt++;
1459                 time_status |= STA_PPSWANDER;
1460                 return;
1461         }
1462         if (time_status & STA_PPSFREQ) {
1463                 if (u_usec < 0) {
1464                         pps_freq -= -u_usec >> PPS_AVG;
1465                         if (pps_freq < -time_tolerance)
1466                                 pps_freq = -time_tolerance;
1467                         u_usec = -u_usec;
1468                 } else {
1469                         pps_freq += u_usec >> PPS_AVG;
1470                         if (pps_freq > time_tolerance)
1471                                 pps_freq = time_tolerance;
1472                 }
1473         }
1474 
1475         /*
1476          * Here the calibration interval is adjusted. If the maximum
1477          * time difference is greater than tick / 4, reduce the interval
1478          * by half. If this is not the case for four consecutive
1479          * intervals, double the interval.
1480          */
1481         if (u_usec << pps_shift > bigtick >> 2) {
1482                 pps_intcnt = 0;
1483                 if (pps_shift > PPS_SHIFT)
1484                         pps_shift--;
1485         } else if (pps_intcnt >= 4) {
1486                 pps_intcnt = 0;
1487                 if (pps_shift < PPS_SHIFTMAX)
1488                         pps_shift++;
1489         } else
1490                 pps_intcnt++;
1491 
1492         /*
1493          * If recovering from kmdb, then make sure the tod chip gets resynced.
1494          * If we took an early exit above, then we don't yet have a stable
1495          * calibration signal to lock onto, so don't mark the tod for sync
1496          * until we get all the way here.
1497          */
1498         {
1499                 int s = hr_clock_lock();
1500 
1501                 tod_needsync = 1;
1502                 hr_clock_unlock(s);
1503         }
1504 }
1505 
1506 /*
1507  * Handle clock tick processing for a thread.
1508  * Check for timer action, enforce CPU rlimit, do profiling etc.
1509  */
1510 void
1511 clock_tick(kthread_t *t, int pending)
1512 {
1513         struct proc *pp;
1514         klwp_id_t    lwp;
1515         struct as *as;
1516         clock_t ticks;
1517         int     poke = 0;               /* notify another CPU */
1518         int     user_mode;
1519         size_t   rss;
1520         int i, total_usec, usec;
1521         rctl_qty_t secs;
1522 
1523         ASSERT(pending > 0);
1524 
1525         /* Must be operating on a lwp/thread */
1526         if ((lwp = ttolwp(t)) == NULL) {
1527                 panic("clock_tick: no lwp");
1528                 /*NOTREACHED*/
1529         }
1530 
1531         for (i = 0; i < pending; i++) {
1532                 CL_TICK(t);     /* Class specific tick processing */
1533                 DTRACE_SCHED1(tick, kthread_t *, t);
1534         }
1535 
1536         pp = ttoproc(t);
1537 
1538         /* pp->p_lock makes sure that the thread does not exit */
1539         ASSERT(MUTEX_HELD(&pp->p_lock));
1540 
1541         user_mode = (lwp->lwp_state == LWP_USER);
1542 
1543         ticks = (pp->p_utime + pp->p_stime) % hz;
1544         /*
1545          * Update process times. Should use high res clock and state
1546          * changes instead of statistical sampling method. XXX
1547          */
1548         if (user_mode) {
1549                 pp->p_utime += pending;
1550         } else {
1551                 pp->p_stime += pending;
1552         }
1553 
1554         pp->p_ttime += pending;
1555         as = pp->p_as;
1556 
1557         /*
1558          * Update user profiling statistics. Get the pc from the
1559          * lwp when the AST happens.
1560          */
1561         if (pp->p_prof.pr_scale) {
1562                 atomic_add_32(&lwp->lwp_oweupc, (int32_t)pending);
1563                 if (user_mode) {
1564                         poke = 1;
1565                         aston(t);
1566                 }
1567         }
1568 
1569         /*
1570          * If CPU was in user state, process lwp-virtual time
1571          * interval timer. The value passed to itimerdecr() has to be
1572          * in microseconds and has to be less than one second. Hence
1573          * this loop.
1574          */
1575         total_usec = usec_per_tick * pending;
1576         while (total_usec > 0) {
1577                 usec = MIN(total_usec, (MICROSEC - 1));
1578                 if (user_mode &&
1579                     timerisset(&lwp->lwp_timer[ITIMER_VIRTUAL].it_value) &&
1580                     itimerdecr(&lwp->lwp_timer[ITIMER_VIRTUAL], usec) == 0) {
1581                         poke = 1;
1582                         sigtoproc(pp, t, SIGVTALRM);
1583                 }
1584                 total_usec -= usec;
1585         }
1586 
1587         /*
1588          * If CPU was in user state, process lwp-profile
1589          * interval timer.
1590          */
1591         total_usec = usec_per_tick * pending;
1592         while (total_usec > 0) {
1593                 usec = MIN(total_usec, (MICROSEC - 1));
1594                 if (timerisset(&lwp->lwp_timer[ITIMER_PROF].it_value) &&
1595                     itimerdecr(&lwp->lwp_timer[ITIMER_PROF], usec) == 0) {
1596                         poke = 1;
1597                         sigtoproc(pp, t, SIGPROF);
1598                 }
1599                 total_usec -= usec;
1600         }
1601 
1602         /*
1603          * Enforce CPU resource controls:
1604          *   (a) process.max-cpu-time resource control
1605          *
1606          * Perform the check only if we have accumulated more a second.
1607          */
1608         if ((ticks + pending) >= hz) {
1609                 (void) rctl_test(rctlproc_legacy[RLIMIT_CPU], pp->p_rctls, pp,
1610                     (pp->p_utime + pp->p_stime)/hz, RCA_UNSAFE_SIGINFO);
1611         }
1612 
1613         /*
1614          *   (b) task.max-cpu-time resource control
1615          *
1616          * If we have accumulated enough ticks, increment the task CPU
1617          * time usage and test for the resource limit. This minimizes the
1618          * number of calls to the rct_test(). The task CPU time mutex
1619          * is highly contentious as many processes can be sharing a task.
1620          */
1621         if (pp->p_ttime >= clock_tick_proc_max) {
1622                 secs = task_cpu_time_incr(pp->p_task, pp->p_ttime);
1623                 pp->p_ttime = 0;
1624                 if (secs) {
1625                         (void) rctl_test(rc_task_cpu_time, pp->p_task->tk_rctls,
1626                             pp, secs, RCA_UNSAFE_SIGINFO);
1627                 }
1628         }
1629 
1630         /*
1631          * Update memory usage for the currently running process.
1632          */
1633         rss = rm_asrss(as);
1634         PTOU(pp)->u_mem += rss;
1635         if (rss > PTOU(pp)->u_mem_max)
1636                 PTOU(pp)->u_mem_max = rss;
1637 
1638         /*
1639          * Notify the CPU the thread is running on.
1640          */
1641         if (poke && t->t_cpu != CPU)
1642                 poke_cpu(t->t_cpu->cpu_id);
1643 }
1644 
1645 void
1646 profil_tick(uintptr_t upc)
1647 {
1648         int ticks;
1649         proc_t *p = ttoproc(curthread);
1650         klwp_t *lwp = ttolwp(curthread);
1651         struct prof *pr = &p->p_prof;
1652 
1653         do {
1654                 ticks = lwp->lwp_oweupc;
1655         } while (atomic_cas_32(&lwp->lwp_oweupc, ticks, 0) != ticks);
1656 
1657         mutex_enter(&p->p_pflock);
1658         if (pr->pr_scale >= 2 && upc >= pr->pr_off) {
1659                 /*
1660                  * Old-style profiling
1661                  */
1662                 uint16_t *slot = pr->pr_base;
1663                 uint16_t old, new;
1664                 if (pr->pr_scale != 2) {
1665                         uintptr_t delta = upc - pr->pr_off;
1666                         uintptr_t byteoff = ((delta >> 16) * pr->pr_scale) +
1667                             (((delta & 0xffff) * pr->pr_scale) >> 16);
1668                         if (byteoff >= (uintptr_t)pr->pr_size) {
1669                                 mutex_exit(&p->p_pflock);
1670                                 return;
1671                         }
1672                         slot += byteoff / sizeof (uint16_t);
1673                 }
1674                 if (fuword16(slot, &old) < 0 ||
1675                     (new = old + ticks) > SHRT_MAX ||
1676                     suword16(slot, new) < 0) {
1677                         pr->pr_scale = 0;
1678                 }
1679         } else if (pr->pr_scale == 1) {
1680                 /*
1681                  * PC Sampling
1682                  */
1683                 model_t model = lwp_getdatamodel(lwp);
1684                 int result;
1685 #ifdef __lint
1686                 model = model;
1687 #endif
1688                 while (ticks-- > 0) {
1689                         if (pr->pr_samples == pr->pr_size) {
1690                                 /* buffer full, turn off sampling */
1691                                 pr->pr_scale = 0;
1692                                 break;
1693                         }
1694                         switch (SIZEOF_PTR(model)) {
1695                         case sizeof (uint32_t):
1696                                 result = suword32(pr->pr_base, (uint32_t)upc);
1697                                 break;
1698 #ifdef _LP64
1699                         case sizeof (uint64_t):
1700                                 result = suword64(pr->pr_base, (uint64_t)upc);
1701                                 break;
1702 #endif
1703                         default:
1704                                 cmn_err(CE_WARN, "profil_tick: unexpected "
1705                                     "data model");
1706                                 result = -1;
1707                                 break;
1708                         }
1709                         if (result != 0) {
1710                                 pr->pr_scale = 0;
1711                                 break;
1712                         }
1713                         pr->pr_base = (caddr_t)pr->pr_base + SIZEOF_PTR(model);
1714                         pr->pr_samples++;
1715                 }
1716         }
1717         mutex_exit(&p->p_pflock);
1718 }
1719 
1720 static void
1721 delay_wakeup(void *arg)
1722 {
1723         kthread_t       *t = arg;
1724 
1725         mutex_enter(&t->t_delay_lock);
1726         cv_signal(&t->t_delay_cv);
1727         mutex_exit(&t->t_delay_lock);
1728 }
1729 
1730 /*
1731  * The delay(9F) man page indicates that it can only be called from user or
1732  * kernel context - detect and diagnose bad calls. The following macro will
1733  * produce a limited number of messages identifying bad callers.  This is done
1734  * in a macro so that caller() is meaningful. When a bad caller is identified,
1735  * switching to 'drv_usecwait(TICK_TO_USEC(ticks));' may be appropriate.
1736  */
1737 #define DELAY_CONTEXT_CHECK()   {                                       \
1738         uint32_t        m;                                              \
1739         char            *f;                                             \
1740         ulong_t         off;                                            \
1741                                                                         \
1742         m = delay_from_interrupt_msg;                                   \
1743         if (delay_from_interrupt_diagnose && servicing_interrupt() &&   \
1744             !panicstr && !devinfo_freeze &&                             \
1745             atomic_cas_32(&delay_from_interrupt_msg, m ? m : 1, m-1)) {     \
1746                 f = modgetsymname((uintptr_t)caller(), &off);               \
1747                 cmn_err(CE_WARN, "delay(9F) called from "               \
1748                     "interrupt context: %s`%s",                         \
1749                     mod_containing_pc(caller()), f ? f : "...");        \
1750         }                                                               \
1751 }
1752 
1753 /*
1754  * delay_common: common delay code.
1755  */
1756 static void
1757 delay_common(clock_t ticks)
1758 {
1759         kthread_t       *t = curthread;
1760         clock_t         deadline;
1761         clock_t         timeleft;
1762         callout_id_t    id;
1763 
1764         /* If timeouts aren't running all we can do is spin. */
1765         if (panicstr || devinfo_freeze) {
1766                 /* Convert delay(9F) call into drv_usecwait(9F) call. */
1767                 if (ticks > 0)
1768                         drv_usecwait(TICK_TO_USEC(ticks));
1769                 return;
1770         }
1771 
1772         deadline = ddi_get_lbolt() + ticks;
1773         while ((timeleft = deadline - ddi_get_lbolt()) > 0) {
1774                 mutex_enter(&t->t_delay_lock);
1775                 id = timeout_default(delay_wakeup, t, timeleft);
1776                 cv_wait(&t->t_delay_cv, &t->t_delay_lock);
1777                 mutex_exit(&t->t_delay_lock);
1778                 (void) untimeout_default(id, 0);
1779         }
1780 }
1781 
1782 /*
1783  * Delay specified number of clock ticks.
1784  */
1785 void
1786 delay(clock_t ticks)
1787 {
1788         DELAY_CONTEXT_CHECK();
1789 
1790         delay_common(ticks);
1791 }
1792 
1793 /*
1794  * Delay a random number of clock ticks between 1 and ticks.
1795  */
1796 void
1797 delay_random(clock_t ticks)
1798 {
1799         int     r;
1800 
1801         DELAY_CONTEXT_CHECK();
1802 
1803         (void) random_get_pseudo_bytes((void *)&r, sizeof (r));
1804         if (ticks == 0)
1805                 ticks = 1;
1806         ticks = (r % ticks) + 1;
1807         delay_common(ticks);
1808 }
1809 
1810 /*
1811  * Like delay, but interruptible by a signal.
1812  */
1813 int
1814 delay_sig(clock_t ticks)
1815 {
1816         kthread_t       *t = curthread;
1817         clock_t         deadline;
1818         clock_t         rc;
1819 
1820         /* If timeouts aren't running all we can do is spin. */
1821         if (panicstr || devinfo_freeze) {
1822                 if (ticks > 0)
1823                         drv_usecwait(TICK_TO_USEC(ticks));
1824                 return (0);
1825         }
1826 
1827         deadline = ddi_get_lbolt() + ticks;
1828         mutex_enter(&t->t_delay_lock);
1829         do {
1830                 rc = cv_timedwait_sig(&t->t_delay_cv,
1831                     &t->t_delay_lock, deadline);
1832                 /* loop until past deadline or signaled */
1833         } while (rc > 0);
1834         mutex_exit(&t->t_delay_lock);
1835         if (rc == 0)
1836                 return (EINTR);
1837         return (0);
1838 }
1839 
1840 
1841 #define SECONDS_PER_DAY 86400
1842 
1843 /*
1844  * Initialize the system time based on the TOD chip.  approx is used as
1845  * an approximation of time (e.g. from the filesystem) in the event that
1846  * the TOD chip has been cleared or is unresponsive.  An approx of -1
1847  * means the filesystem doesn't keep time.
1848  */
1849 void
1850 clkset(time_t approx)
1851 {
1852         timestruc_t ts;
1853         int spl;
1854         int set_clock = 0;
1855 
1856         mutex_enter(&tod_lock);
1857         ts = tod_get();
1858 
1859         if (ts.tv_sec > 365 * SECONDS_PER_DAY) {
1860                 /*
1861                  * If the TOD chip is reporting some time after 1971,
1862                  * then it probably didn't lose power or become otherwise
1863                  * cleared in the recent past;  check to assure that
1864                  * the time coming from the filesystem isn't in the future
1865                  * according to the TOD chip.
1866                  */
1867                 if (approx != -1 && approx > ts.tv_sec) {
1868                         cmn_err(CE_WARN, "Last shutdown is later "
1869                             "than time on time-of-day chip; check date.");
1870                 }
1871         } else {
1872                 /*
1873                  * If the TOD chip isn't giving correct time, set it to the
1874                  * greater of i) approx and ii) 1987. That way if approx
1875                  * is negative or is earlier than 1987, we set the clock
1876                  * back to a time when Oliver North, ALF and Dire Straits
1877                  * were all on the collective brain:  1987.
1878                  */
1879                 timestruc_t tmp;
1880                 time_t diagnose_date = (1987 - 1970) * 365 * SECONDS_PER_DAY;
1881                 ts.tv_sec = (approx > diagnose_date ? approx : diagnose_date);
1882                 ts.tv_nsec = 0;
1883 
1884                 /*
1885                  * Attempt to write the new time to the TOD chip.  Set spl high
1886                  * to avoid getting preempted between the tod_set and tod_get.
1887                  */
1888                 spl = splhi();
1889                 tod_set(ts);
1890                 tmp = tod_get();
1891                 splx(spl);
1892 
1893                 if (tmp.tv_sec != ts.tv_sec && tmp.tv_sec != ts.tv_sec + 1) {
1894                         tod_broken = 1;
1895                         dosynctodr = 0;
1896                         cmn_err(CE_WARN, "Time-of-day chip unresponsive.");
1897                 } else {
1898                         cmn_err(CE_WARN, "Time-of-day chip had "
1899                             "incorrect date; check and reset.");
1900                 }
1901                 set_clock = 1;
1902         }
1903 
1904         if (!boot_time) {
1905                 boot_time = ts.tv_sec;
1906                 set_clock = 1;
1907         }
1908         if (!boot_hrtime) {
1909                 boot_hrtime = gethrtime();
1910         }
1911 
1912         if (set_clock)
1913                 set_hrestime(&ts);
1914 
1915         mutex_exit(&tod_lock);
1916 }
1917 
1918 int     timechanged;    /* for testing if the system time has been reset */
1919 
1920 void
1921 set_hrestime(timestruc_t *ts)
1922 {
1923         int spl = hr_clock_lock();
1924         hrestime = *ts;
1925         membar_enter(); /* hrestime must be visible before timechanged++ */
1926         timedelta = 0;
1927         timechanged++;
1928         hr_clock_unlock(spl);
1929         callout_hrestime();
1930 }
1931 
1932 static uint_t deadman_seconds;
1933 static uint32_t deadman_panics;
1934 static int deadman_enabled = 0;
1935 static int deadman_panic_timers = 1;
1936 
1937 static void
1938 deadman(void)
1939 {
1940         if (panicstr) {
1941                 /*
1942                  * During panic, other CPUs besides the panic
1943                  * master continue to handle cyclics and some other
1944                  * interrupts.  The code below is intended to be
1945                  * single threaded, so any CPU other than the master
1946                  * must keep out.
1947                  */
1948                 if (CPU->cpu_id != panic_cpu.cpu_id)
1949                         return;
1950 
1951                 if (!deadman_panic_timers)
1952                         return; /* allow all timers to be manually disabled */
1953 
1954                 /*
1955                  * If we are generating a crash dump or syncing filesystems and
1956                  * the corresponding timer is set, decrement it and re-enter
1957                  * the panic code to abort it and advance to the next state.
1958                  * The panic states and triggers are explained in panic.c.
1959                  */
1960                 if (panic_dump) {
1961                         if (dump_timeleft && (--dump_timeleft == 0)) {
1962                                 panic("panic dump timeout");
1963                                 /*NOTREACHED*/
1964                         }
1965                 } else if (panic_sync) {
1966                         if (sync_timeleft && (--sync_timeleft == 0)) {
1967                                 panic("panic sync timeout");
1968                                 /*NOTREACHED*/
1969                         }
1970                 }
1971 
1972                 return;
1973         }
1974 
1975         if (deadman_counter != CPU->cpu_deadman_counter) {
1976                 CPU->cpu_deadman_counter = deadman_counter;
1977                 CPU->cpu_deadman_countdown = deadman_seconds;
1978                 return;
1979         }
1980 
1981         if (--CPU->cpu_deadman_countdown > 0)
1982                 return;
1983 
1984         /*
1985          * Regardless of whether or not we actually bring the system down,
1986          * bump the deadman_panics variable.
1987          *
1988          * N.B. deadman_panics is incremented once for each CPU that
1989          * passes through here.  It's expected that all the CPUs will
1990          * detect this condition within one second of each other, so
1991          * when deadman_enabled is off, deadman_panics will
1992          * typically be a multiple of the total number of CPUs in
1993          * the system.
1994          */
1995         atomic_inc_32(&deadman_panics);
1996 
1997         if (!deadman_enabled) {
1998                 CPU->cpu_deadman_countdown = deadman_seconds;
1999                 return;
2000         }
2001 
2002         /*
2003          * If we're here, we want to bring the system down.
2004          */
2005         panic("deadman: timed out after %d seconds of clock "
2006             "inactivity", deadman_seconds);
2007         /*NOTREACHED*/
2008 }
2009 
2010 /*ARGSUSED*/
2011 static void
2012 deadman_online(void *arg, cpu_t *cpu, cyc_handler_t *hdlr, cyc_time_t *when)
2013 {
2014         cpu->cpu_deadman_counter = 0;
2015         cpu->cpu_deadman_countdown = deadman_seconds;
2016 
2017         hdlr->cyh_func = (cyc_func_t)deadman;
2018         hdlr->cyh_level = CY_HIGH_LEVEL;
2019         hdlr->cyh_arg = NULL;
2020 
2021         /*
2022          * Stagger the CPUs so that they don't all run deadman() at
2023          * the same time.  Simplest reason to do this is to make it
2024          * more likely that only one CPU will panic in case of a
2025          * timeout.  This is (strictly speaking) an aesthetic, not a
2026          * technical consideration.
2027          */
2028         when->cyt_when = cpu->cpu_id * (NANOSEC / NCPU);
2029         when->cyt_interval = NANOSEC;
2030 }
2031 
2032 
2033 void
2034 deadman_init(void)
2035 {
2036         cyc_omni_handler_t hdlr;
2037 
2038         if (deadman_seconds == 0)
2039                 deadman_seconds = snoop_interval / MICROSEC;
2040 
2041         if (snooping)
2042                 deadman_enabled = 1;
2043 
2044         hdlr.cyo_online = deadman_online;
2045         hdlr.cyo_offline = NULL;
2046         hdlr.cyo_arg = NULL;
2047 
2048         mutex_enter(&cpu_lock);
2049         deadman_cyclic = cyclic_add_omni(&hdlr);
2050         mutex_exit(&cpu_lock);
2051 }
2052 
2053 /*
2054  * tod_fault() is for updating tod validate mechanism state:
2055  * (1) TOD_NOFAULT: for resetting the state to 'normal'.
2056  *     currently used for debugging only
2057  * (2) The following four cases detected by tod validate mechanism:
2058  *       TOD_REVERSED: current tod value is less than previous value.
2059  *       TOD_STALLED: current tod value hasn't advanced.
2060  *       TOD_JUMPED: current tod value advanced too far from previous value.
2061  *       TOD_RATECHANGED: the ratio between average tod delta and
2062  *       average tick delta has changed.
2063  * (3) TOD_RDONLY: when the TOD clock is not writeable e.g. because it is
2064  *     a virtual TOD provided by a hypervisor.
2065  */
2066 enum tod_fault_type
2067 tod_fault(enum tod_fault_type ftype, int off)
2068 {
2069         ASSERT(MUTEX_HELD(&tod_lock));
2070 
2071         if (tod_faulted != ftype) {
2072                 switch (ftype) {
2073                 case TOD_NOFAULT:
2074                         plat_tod_fault(TOD_NOFAULT);
2075                         cmn_err(CE_NOTE, "Restarted tracking "
2076                             "Time of Day clock.");
2077                         tod_faulted = ftype;
2078                         break;
2079                 case TOD_REVERSED:
2080                 case TOD_JUMPED:
2081                         if (tod_faulted == TOD_NOFAULT) {
2082                                 plat_tod_fault(ftype);
2083                                 cmn_err(CE_WARN, "Time of Day clock error: "
2084                                     "reason [%s by 0x%x]. -- "
2085                                     " Stopped tracking Time Of Day clock.",
2086                                     tod_fault_table[ftype], off);
2087                                 tod_faulted = ftype;
2088                         }
2089                         break;
2090                 case TOD_STALLED:
2091                 case TOD_RATECHANGED:
2092                         if (tod_faulted == TOD_NOFAULT) {
2093                                 plat_tod_fault(ftype);
2094                                 cmn_err(CE_WARN, "Time of Day clock error: "
2095                                     "reason [%s]. -- "
2096                                     " Stopped tracking Time Of Day clock.",
2097                                     tod_fault_table[ftype]);
2098                                 tod_faulted = ftype;
2099                         }
2100                         break;
2101                 case TOD_RDONLY:
2102                         if (tod_faulted == TOD_NOFAULT) {
2103                                 plat_tod_fault(ftype);
2104                                 cmn_err(CE_NOTE, "!Time of Day clock is "
2105                                     "Read-Only; set of Date/Time will not "
2106                                     "persist across reboot.");
2107                                 tod_faulted = ftype;
2108                         }
2109                         break;
2110                 default:
2111                         break;
2112                 }
2113         }
2114         return (tod_faulted);
2115 }
2116 
2117 /*
2118  * Two functions that allow tod_status_flag to be manipulated by functions
2119  * external to this file.
2120  */
2121 
2122 void
2123 tod_status_set(int tod_flag)
2124 {
2125         tod_status_flag |= tod_flag;
2126 }
2127 
2128 void
2129 tod_status_clear(int tod_flag)
2130 {
2131         tod_status_flag &= ~tod_flag;
2132 }
2133 
2134 /*
2135  * Record a timestamp and the value passed to tod_set().  The next call to
2136  * tod_validate() can use these values, prev_set_tick and prev_set_tod,
2137  * when checking the timestruc_t returned by tod_get().  Ordinarily,
2138  * tod_validate() will use prev_tick and prev_tod for this task but these
2139  * become obsolete, and will be re-assigned with the prev_set_* values,
2140  * in the case when the TOD is re-written.
2141  */
2142 void
2143 tod_set_prev(timestruc_t ts)
2144 {
2145         if ((tod_validate_enable == 0) || (tod_faulted != TOD_NOFAULT) ||
2146             tod_validate_deferred) {
2147                 return;
2148         }
2149         prev_set_tick = gethrtime();
2150         /*
2151          * A negative value will be set to zero in utc_to_tod() so we fake
2152          * a zero here in such a case.  This would need to change if the
2153          * behavior of utc_to_tod() changes.
2154          */
2155         prev_set_tod = ts.tv_sec < 0 ? 0 : ts.tv_sec;
2156 }
2157 
2158 /*
2159  * tod_validate() is used for checking values returned by tod_get().
2160  * Four error cases can be detected by this routine:
2161  *   TOD_REVERSED: current tod value is less than previous.
2162  *   TOD_STALLED: current tod value hasn't advanced.
2163  *   TOD_JUMPED: current tod value advanced too far from previous value.
2164  *   TOD_RATECHANGED: the ratio between average tod delta and
2165  *   average tick delta has changed.
2166  */
2167 time_t
2168 tod_validate(time_t tod)
2169 {
2170         time_t diff_tod;
2171         hrtime_t diff_tick;
2172 
2173         long dtick;
2174         int dtick_delta;
2175 
2176         int off = 0;
2177         enum tod_fault_type tod_bad = TOD_NOFAULT;
2178 
2179         static int firsttime = 1;
2180 
2181         static time_t prev_tod = 0;
2182         static hrtime_t prev_tick = 0;
2183         static long dtick_avg = TOD_REF_FREQ;
2184 
2185         int cpr_resume_done = 0;
2186         int dr_resume_done = 0;
2187 
2188         hrtime_t tick = gethrtime();
2189 
2190         ASSERT(MUTEX_HELD(&tod_lock));
2191 
2192         /*
2193          * tod_validate_enable is patchable via /etc/system.
2194          * If TOD is already faulted, or if TOD validation is deferred,
2195          * there is nothing to do.
2196          */
2197         if ((tod_validate_enable == 0) || (tod_faulted != TOD_NOFAULT) ||
2198             tod_validate_deferred) {
2199                 return (tod);
2200         }
2201 
2202         /*
2203          * If this is the first time through, we just need to save the tod
2204          * we were called with and hrtime so we can use them next time to
2205          * validate tod_get().
2206          */
2207         if (firsttime) {
2208                 firsttime = 0;
2209                 prev_tod = tod;
2210                 prev_tick = tick;
2211                 return (tod);
2212         }
2213 
2214         /*
2215          * Handle any flags that have been turned on by tod_status_set().
2216          * In the case where a tod_set() is done and then a subsequent
2217          * tod_get() fails (ie, both TOD_SET_DONE and TOD_GET_FAILED are
2218          * true), we treat the TOD_GET_FAILED with precedence by switching
2219          * off the flag, returning tod and leaving TOD_SET_DONE asserted
2220          * until such time as tod_get() completes successfully.
2221          */
2222         if (tod_status_flag & TOD_GET_FAILED) {
2223                 /*
2224                  * tod_get() has encountered an issue, possibly transitory,
2225                  * when reading TOD.  We'll just return the incoming tod
2226                  * value (which is actually hrestime.tv_sec in this case)
2227                  * and when we get a genuine tod, following a successful
2228                  * tod_get(), we can validate using prev_tod and prev_tick.
2229                  */
2230                 tod_status_flag &= ~TOD_GET_FAILED;
2231                 return (tod);
2232         } else if (tod_status_flag & TOD_SET_DONE) {
2233                 /*
2234                  * TOD has been modified.  Just before the TOD was written,
2235                  * tod_set_prev() saved tod and hrtime; we can now use
2236                  * those values, prev_set_tod and prev_set_tick, to validate
2237                  * the incoming tod that's just been read.
2238                  */
2239                 prev_tod = prev_set_tod;
2240                 prev_tick = prev_set_tick;
2241                 dtick_avg = TOD_REF_FREQ;
2242                 tod_status_flag &= ~TOD_SET_DONE;
2243                 /*
2244                  * If a tod_set() preceded a cpr_suspend() without an
2245                  * intervening tod_validate(), we need to ensure that a
2246                  * TOD_JUMPED condition is ignored.
2247                  * Note this isn't a concern in the case of DR as we've
2248                  * just reassigned dtick_avg, above.
2249                  */
2250                 if (tod_status_flag & TOD_CPR_RESUME_DONE) {
2251                         cpr_resume_done = 1;
2252                         tod_status_flag &= ~TOD_CPR_RESUME_DONE;
2253                 }
2254         } else if (tod_status_flag & TOD_CPR_RESUME_DONE) {
2255                 /*
2256                  * The system's coming back from a checkpoint resume.
2257                  */
2258                 cpr_resume_done = 1;
2259                 tod_status_flag &= ~TOD_CPR_RESUME_DONE;
2260                 /*
2261                  * We need to handle the possibility of a CPR suspend
2262                  * operation having been initiated whilst a DR event was
2263                  * in-flight.
2264                  */
2265                 if (tod_status_flag & TOD_DR_RESUME_DONE) {
2266                         dr_resume_done = 1;
2267                         tod_status_flag &= ~TOD_DR_RESUME_DONE;
2268                 }
2269         } else if (tod_status_flag & TOD_DR_RESUME_DONE) {
2270                 /*
2271                  * A Dynamic Reconfiguration event has taken place.
2272                  */
2273                 dr_resume_done = 1;
2274                 tod_status_flag &= ~TOD_DR_RESUME_DONE;
2275         }
2276 
2277         /* test hook */
2278         switch (tod_unit_test) {
2279         case 1: /* for testing jumping tod */
2280                 tod += tod_test_injector;
2281                 tod_unit_test = 0;
2282                 break;
2283         case 2: /* for testing stuck tod bit */
2284                 tod |= 1 << tod_test_injector;
2285                 tod_unit_test = 0;
2286                 break;
2287         case 3: /* for testing stalled tod */
2288                 tod = prev_tod;
2289                 tod_unit_test = 0;
2290                 break;
2291         case 4: /* reset tod fault status */
2292                 (void) tod_fault(TOD_NOFAULT, 0);
2293                 tod_unit_test = 0;
2294                 break;
2295         default:
2296                 break;
2297         }
2298 
2299         diff_tod = tod - prev_tod;
2300         diff_tick = tick - prev_tick;
2301 
2302         ASSERT(diff_tick >= 0);
2303 
2304         if (diff_tod < 0) {
2305                 /* ERROR - tod reversed */
2306                 tod_bad = TOD_REVERSED;
2307                 off = (int)(prev_tod - tod);
2308         } else if (diff_tod == 0) {
2309                 /* tod did not advance */
2310                 if (diff_tick > TOD_STALL_THRESHOLD) {
2311                         /* ERROR - tod stalled */
2312                         tod_bad = TOD_STALLED;
2313                 } else {
2314                         /*
2315                          * Make sure we don't update prev_tick
2316                          * so that diff_tick is calculated since
2317                          * the first diff_tod == 0
2318                          */
2319                         return (tod);
2320                 }
2321         } else {
2322                 /* calculate dtick */
2323                 dtick = diff_tick / diff_tod;
2324 
2325                 /* update dtick averages */
2326                 dtick_avg += ((dtick - dtick_avg) / TOD_FILTER_N);
2327 
2328                 /*
2329                  * Calculate dtick_delta as
2330                  * variation from reference freq in quartiles
2331                  */
2332                 dtick_delta = (dtick_avg - TOD_REF_FREQ) /
2333                     (TOD_REF_FREQ >> 2);
2334 
2335                 /*
2336                  * Even with a perfectly functioning TOD device,
2337                  * when the number of elapsed seconds is low the
2338                  * algorithm can calculate a rate that is beyond
2339                  * tolerance, causing an error.  The algorithm is
2340                  * inaccurate when elapsed time is low (less than
2341                  * 5 seconds).
2342                  */
2343                 if (diff_tod > 4) {
2344                         if (dtick < TOD_JUMP_THRESHOLD) {
2345                                 /*
2346                                  * If we've just done a CPR resume, we detect
2347                                  * a jump in the TOD but, actually, what's
2348                                  * happened is that the TOD has been increasing
2349                                  * whilst the system was suspended and the tick
2350                                  * count hasn't kept up.  We consider the first
2351                                  * occurrence of this after a resume as normal
2352                                  * and ignore it; otherwise, in a non-resume
2353                                  * case, we regard it as a TOD problem.
2354                                  */
2355                                 if (!cpr_resume_done) {
2356                                         /* ERROR - tod jumped */
2357                                         tod_bad = TOD_JUMPED;
2358                                         off = (int)diff_tod;
2359                                 }
2360                         }
2361                         if (dtick_delta) {
2362                                 /*
2363                                  * If we've just done a DR resume, dtick_avg
2364                                  * can go a bit askew so we reset it and carry
2365                                  * on; otherwise, the TOD is in error.
2366                                  */
2367                                 if (dr_resume_done) {
2368                                         dtick_avg = TOD_REF_FREQ;
2369                                 } else {
2370                                         /* ERROR - change in clock rate */
2371                                         tod_bad = TOD_RATECHANGED;
2372                                 }
2373                         }
2374                 }
2375         }
2376 
2377         if (tod_bad != TOD_NOFAULT) {
2378                 (void) tod_fault(tod_bad, off);
2379 
2380                 /*
2381                  * Disable dosynctodr since we are going to fault
2382                  * the TOD chip anyway here
2383                  */
2384                 dosynctodr = 0;
2385 
2386                 /*
2387                  * Set tod to the correct value from hrestime
2388                  */
2389                 tod = hrestime.tv_sec;
2390         }
2391 
2392         prev_tod = tod;
2393         prev_tick = tick;
2394         return (tod);
2395 }
2396 
2397 static void
2398 calcloadavg(int nrun, uint64_t *hp_ave)
2399 {
2400         static int64_t f[3] = { 135, 27, 9 };
2401         uint_t i;
2402         int64_t q, r;
2403 
2404         /*
2405          * Compute load average over the last 1, 5, and 15 minutes
2406          * (60, 300, and 900 seconds).  The constants in f[3] are for
2407          * exponential decay:
2408          * (1 - exp(-1/60)) << 13 = 135,
2409          * (1 - exp(-1/300)) << 13 = 27,
2410          * (1 - exp(-1/900)) << 13 = 9.
2411          */
2412 
2413         /*
2414          * a little hoop-jumping to avoid integer overflow
2415          */
2416         for (i = 0; i < 3; i++) {
2417                 q = (hp_ave[i]  >> 16) << 7;
2418                 r = (hp_ave[i]  & 0xffff) << 7;
2419                 hp_ave[i] += ((nrun - q) * f[i] - ((r * f[i]) >> 16)) >> 4;
2420         }
2421 }
2422 
2423 /*
2424  * lbolt_hybrid() is used by ddi_get_lbolt() and ddi_get_lbolt64() to
2425  * calculate the value of lbolt according to the current mode. In the event
2426  * driven mode (the default), lbolt is calculated by dividing the current hires
2427  * time by the number of nanoseconds per clock tick. In the cyclic driven mode
2428  * an internal variable is incremented at each firing of the lbolt cyclic
2429  * and returned by lbolt_cyclic_driven().
2430  *
2431  * The system will transition from event to cyclic driven mode when the number
2432  * of calls to lbolt_event_driven() exceeds the (per CPU) threshold within a
2433  * window of time. It does so by reprograming lbolt_cyclic from CY_INFINITY to
2434  * nsec_per_tick. The lbolt cyclic will remain ON while at least one CPU is
2435  * causing enough activity to cross the thresholds.
2436  */
2437 int64_t
2438 lbolt_bootstrap(void)
2439 {
2440         return (0);
2441 }
2442 
2443 /* ARGSUSED */
2444 uint_t
2445 lbolt_ev_to_cyclic(caddr_t arg1, caddr_t arg2)
2446 {
2447         hrtime_t ts, exp;
2448         int ret;
2449 
2450         ASSERT(lbolt_hybrid != lbolt_cyclic_driven);
2451 
2452         kpreempt_disable();
2453 
2454         ts = gethrtime();
2455         lb_info->lbi_internal = (ts/nsec_per_tick);
2456 
2457         /*
2458          * Align the next expiration to a clock tick boundary.
2459          */
2460         exp = ts + nsec_per_tick - 1;
2461         exp = (exp/nsec_per_tick) * nsec_per_tick;
2462 
2463         ret = cyclic_reprogram(lb_info->id.lbi_cyclic_id, exp);
2464         ASSERT(ret);
2465 
2466         lbolt_hybrid = lbolt_cyclic_driven;
2467         lb_info->lbi_cyc_deactivate = B_FALSE;
2468         lb_info->lbi_cyc_deac_start = lb_info->lbi_internal;
2469 
2470         kpreempt_enable();
2471 
2472         ret = atomic_dec_32_nv(&lb_info->lbi_token);
2473         ASSERT(ret == 0);
2474 
2475         return (1);
2476 }
2477 
2478 int64_t
2479 lbolt_event_driven(void)
2480 {
2481         hrtime_t ts;
2482         int64_t lb;
2483         int ret, cpu = CPU->cpu_seqid;
2484 
2485         ts = gethrtime();
2486         ASSERT(ts > 0);
2487 
2488         ASSERT(nsec_per_tick > 0);
2489         lb = (ts/nsec_per_tick);
2490 
2491         /*
2492          * Switch to cyclic mode if the number of calls to this routine
2493          * has reached the threshold within the interval.
2494          */
2495         if ((lb - lb_cpu[cpu].lbc_cnt_start) < lb_info->lbi_thresh_interval) {
2496 
2497                 if (--lb_cpu[cpu].lbc_counter == 0) {
2498                         /*
2499                          * Reached the threshold within the interval, reset
2500                          * the usage statistics.
2501                          */
2502                         lb_cpu[cpu].lbc_counter = lb_info->lbi_thresh_calls;
2503                         lb_cpu[cpu].lbc_cnt_start = lb;
2504 
2505                         /*
2506                          * Make sure only one thread reprograms the
2507                          * lbolt cyclic and changes the mode.
2508                          */
2509                         if (panicstr == NULL &&
2510                             atomic_cas_32(&lb_info->lbi_token, 0, 1) == 0) {
2511 
2512                                 if (lbolt_hybrid == lbolt_cyclic_driven) {
2513                                         ret = atomic_dec_32_nv(
2514                                             &lb_info->lbi_token);
2515                                         ASSERT(ret == 0);
2516                                 } else {
2517                                         lbolt_softint_post();
2518                                 }
2519                         }
2520                 }
2521         } else {
2522                 /*
2523                  * Exceeded the interval, reset the usage statistics.
2524                  */
2525                 lb_cpu[cpu].lbc_counter = lb_info->lbi_thresh_calls;
2526                 lb_cpu[cpu].lbc_cnt_start = lb;
2527         }
2528 
2529         ASSERT(lb >= lb_info->lbi_debug_time);
2530 
2531         return (lb - lb_info->lbi_debug_time);
2532 }
2533 
2534 int64_t
2535 lbolt_cyclic_driven(void)
2536 {
2537         int64_t lb = lb_info->lbi_internal;
2538         int cpu;
2539 
2540         /*
2541          * If a CPU has already prevented the lbolt cyclic from deactivating
2542          * itself, don't bother tracking the usage. Otherwise check if we're
2543          * within the interval and how the per CPU counter is doing.
2544          */
2545         if (lb_info->lbi_cyc_deactivate) {
2546                 cpu = CPU->cpu_seqid;
2547                 if ((lb - lb_cpu[cpu].lbc_cnt_start) <
2548                     lb_info->lbi_thresh_interval) {
2549 
2550                         if (lb_cpu[cpu].lbc_counter == 0)
2551                                 /*
2552                                  * Reached the threshold within the interval,
2553                                  * prevent the lbolt cyclic from turning itself
2554                                  * off.
2555                                  */
2556                                 lb_info->lbi_cyc_deactivate = B_FALSE;
2557                         else
2558                                 lb_cpu[cpu].lbc_counter--;
2559                 } else {
2560                         /*
2561                          * Only reset the usage statistics when we have
2562                          * exceeded the interval.
2563                          */
2564                         lb_cpu[cpu].lbc_counter = lb_info->lbi_thresh_calls;
2565                         lb_cpu[cpu].lbc_cnt_start = lb;
2566                 }
2567         }
2568 
2569         ASSERT(lb >= lb_info->lbi_debug_time);
2570 
2571         return (lb - lb_info->lbi_debug_time);
2572 }
2573 
2574 /*
2575  * The lbolt_cyclic() routine will fire at a nsec_per_tick interval to satisfy
2576  * performance needs of ddi_get_lbolt() and ddi_get_lbolt64() consumers.
2577  * It is inactive by default, and will be activated when switching from event
2578  * to cyclic driven lbolt. The cyclic will turn itself off unless signaled
2579  * by lbolt_cyclic_driven().
2580  */
2581 static void
2582 lbolt_cyclic(void)
2583 {
2584         int ret;
2585 
2586         lb_info->lbi_internal++;
2587 
2588         if (!lbolt_cyc_only) {
2589 
2590                 if (lb_info->lbi_cyc_deactivate) {
2591                         /*
2592                          * Switching from cyclic to event driven mode.
2593                          */
2594                         if (panicstr == NULL &&
2595                             atomic_cas_32(&lb_info->lbi_token, 0, 1) == 0) {
2596 
2597                                 if (lbolt_hybrid == lbolt_event_driven) {
2598                                         ret = atomic_dec_32_nv(
2599                                             &lb_info->lbi_token);
2600                                         ASSERT(ret == 0);
2601                                         return;
2602                                 }
2603 
2604                                 kpreempt_disable();
2605 
2606                                 lbolt_hybrid = lbolt_event_driven;
2607                                 ret = cyclic_reprogram(
2608                                     lb_info->id.lbi_cyclic_id,
2609                                     CY_INFINITY);
2610                                 ASSERT(ret);
2611 
2612                                 kpreempt_enable();
2613 
2614                                 ret = atomic_dec_32_nv(&lb_info->lbi_token);
2615                                 ASSERT(ret == 0);
2616                         }
2617                 }
2618 
2619                 /*
2620                  * The lbolt cyclic should not try to deactivate itself before
2621                  * the sampling period has elapsed.
2622                  */
2623                 if (lb_info->lbi_internal - lb_info->lbi_cyc_deac_start >=
2624                     lb_info->lbi_thresh_interval) {
2625                         lb_info->lbi_cyc_deactivate = B_TRUE;
2626                         lb_info->lbi_cyc_deac_start = lb_info->lbi_internal;
2627                 }
2628         }
2629 }
2630 
2631 /*
2632  * Since the lbolt service was historically cyclic driven, it must be 'stopped'
2633  * when the system drops into the kernel debugger. lbolt_debug_entry() is
2634  * called by the KDI system claim callbacks to record a hires timestamp at
2635  * debug enter time. lbolt_debug_return() is called by the sistem release
2636  * callbacks to account for the time spent in the debugger. The value is then
2637  * accumulated in the lb_info structure and used by lbolt_event_driven() and
2638  * lbolt_cyclic_driven(), as well as the mdb_get_lbolt() routine.
2639  */
2640 void
2641 lbolt_debug_entry(void)
2642 {
2643         if (lbolt_hybrid != lbolt_bootstrap) {
2644                 ASSERT(lb_info != NULL);
2645                 lb_info->lbi_debug_ts = gethrtime();
2646         }
2647 }
2648 
2649 /*
2650  * Calculate the time spent in the debugger and add it to the lbolt info
2651  * structure. We also update the internal lbolt value in case we were in
2652  * cyclic driven mode going in.
2653  */
2654 void
2655 lbolt_debug_return(void)
2656 {
2657         hrtime_t ts;
2658 
2659         if (lbolt_hybrid != lbolt_bootstrap) {
2660                 ASSERT(lb_info != NULL);
2661                 ASSERT(nsec_per_tick > 0);
2662 
2663                 ts = gethrtime();
2664                 lb_info->lbi_internal = (ts/nsec_per_tick);
2665                 lb_info->lbi_debug_time +=
2666                     ((ts - lb_info->lbi_debug_ts)/nsec_per_tick);
2667 
2668                 lb_info->lbi_debug_ts = 0;
2669         }
2670 }