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