bsd/kern/kern_ntptime.c

   1 /*-
   2  ***********************************************************************
   3  *                                                                     *
   4  * Copyright (c) David L. Mills 1993-2001                              *
   5  *                                                                     *
   6  * Permission to use, copy, modify, and distribute this software and   *
   7  * its documentation for any purpose and without fee is hereby         *
   8  * granted, provided that the above copyright notice appears in all    *
   9  * copies and that both the copyright notice and this permission       *
  10  * notice appear in supporting documentation, and that the name        *
  11  * University of Delaware not be used in advertising or publicity      *
  12  * pertaining to distribution of the software without specific,        *
  13  * written prior permission. The University of Delaware makes no       *
  14  * representations about the suitability this software for any         *
  15  * purpose. It is provided "as is" without express or implied          *
  16  * warranty.                                                           *
  17  *                                                                     *
  18  **********************************************************************/
  19
  20
  21 /*
  22  * Adapted from the original sources for FreeBSD and timecounters by:
  23  * Poul-Henning Kamp <phk@FreeBSD.org>.
  24  *
  25  * The 32bit version of the "LP" macros seems a bit past its "sell by"
  26  * date so I have retained only the 64bit version and included it directly
  27  * in this file.
  28  *
  29  * Only minor changes done to interface with the timecounters over in
  30  * sys/kern/kern_clock.c.   Some of the comments below may be (even more)
  31  * confusing and/or plain wrong in that context.
  32  */
  33
  34 /*
  35  * Copyright (c) 2017 Apple Computer, Inc. All rights reserved.
  36  *
  37  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  38  *
  39  * This file contains Original Code and/or Modifications of Original Code
  40  * as defined in and that are subject to the Apple Public Source License
  41  * Version 2.0 (the 'License'). You may not use this file except in
  42  * compliance with the License. The rights granted to you under the License
  43  * may not be used to create, or enable the creation or redistribution of,
  44  * unlawful or unlicensed copies of an Apple operating system, or to
  45  * circumvent, violate, or enable the circumvention or violation of, any
  46  * terms of an Apple operating system software license agreement.
  47  *
  48  * Please obtain a copy of the License at
  49  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  50  *
  51  * The Original Code and all software distributed under the License are
  52  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  53  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  54  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  55  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  56  * Please see the License for the specific language governing rights and
  57  * limitations under the License.
  58  *
  59  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  60  */
  61
  62 #include <sys/cdefs.h>
  63 #include <sys/param.h>
  64 #include <sys/systm.h>
  65 #include <sys/eventhandler.h>
  66 #include <sys/kernel.h>
  67 #include <sys/priv.h>
  68 #include <sys/proc.h>
  69 #include <sys/lock.h>
  70 #include <sys/time.h>
  71 #include <sys/timex.h>
  72 #include <kern/clock.h>
  73 #include <sys/sysctl.h>
  74 #include <sys/sysproto.h>
  75 #include <sys/kauth.h>
  76 #include <kern/thread_call.h>
  77 #include <kern/timer_call.h>
  78 #include <machine/machine_routines.h>
  79 #if CONFIG_MACF
  80 #include <security/mac_framework.h>
  81 #endif
  82 #include <IOKit/IOBSD.h>
  83 #include <os/log.h>
  84
  85 typedef int64_t l_fp;
  86 #define L_ADD(v, u)     ((v) += (u))
  87 #define L_SUB(v, u)     ((v) -= (u))
  88 #define L_ADDHI(v, a)   ((v) += (int64_t)(a) << 32)
  89 #define L_NEG(v)        ((v) = -(v))
  90 #define L_RSHIFT(v, n) \
  91         do { \
  92                 if ((v) < 0) \
  93                         (v) = -(-(v) >> (n)); \
  94                 else \
  95                         (v) = (v) >> (n); \
  96         } while (0)
  97 #define L_MPY(v, a)     ((v) *= (a))
  98 #define L_CLR(v)        ((v) = 0)
  99 #define L_ISNEG(v)      ((v) < 0)
 100 #define L_LINT(v, a) \
 101         do { \
 102                 if ((a) > 0) \
 103                         ((v) = (int64_t)(a) << 32); \
 104                 else \
 105                         ((v) = -((int64_t)(-(a)) << 32)); \
 106         } while (0)
 107 #define L_GINT(v)       ((v) < 0 ? -(-(v) >> 32) : (v) >> 32)
 108
 109 /*
 110  * Generic NTP kernel interface
 111  *
 112  * These routines constitute the Network Time Protocol (NTP) interfaces
 113  * for user and daemon application programs. The ntp_gettime() routine
 114  * provides the time, maximum error (synch distance) and estimated error
 115  * (dispersion) to client user application programs. The ntp_adjtime()
 116  * routine is used by the NTP daemon to adjust the calendar clock to an
 117  * externally derived time. The time offset and related variables set by
 118  * this routine are used by other routines in this module to adjust the
 119  * phase and frequency of the clock discipline loop which controls the
 120  * system clock.
 121  *
 122  * When the kernel time is reckoned directly in nanoseconds (NTP_NANO
 123  * defined), the time at each tick interrupt is derived directly from
 124  * the kernel time variable. When the kernel time is reckoned in
 125  * microseconds, (NTP_NANO undefined), the time is derived from the
 126  * kernel time variable together with a variable representing the
 127  * leftover nanoseconds at the last tick interrupt. In either case, the
 128  * current nanosecond time is reckoned from these values plus an
 129  * interpolated value derived by the clock routines in another
 130  * architecture-specific module. The interpolation can use either a
 131  * dedicated counter or a processor cycle counter (PCC) implemented in
 132  * some architectures.
 133  *
 134  */
 135 /*
 136  * Phase/frequency-lock loop (PLL/FLL) definitions
 137  *
 138  * The nanosecond clock discipline uses two variable types, time
 139  * variables and frequency variables. Both types are represented as 64-
 140  * bit fixed-point quantities with the decimal point between two 32-bit
 141  * halves. On a 32-bit machine, each half is represented as a single
 142  * word and mathematical operations are done using multiple-precision
 143  * arithmetic. On a 64-bit machine, ordinary computer arithmetic is
 144  * used.
 145  *
 146  * A time variable is a signed 64-bit fixed-point number in ns and
 147  * fraction. It represents the remaining time offset to be amortized
 148  * over succeeding tick interrupts. The maximum time offset is about
 149  * 0.5 s and the resolution is about 2.3e-10 ns.
 150  *
 151  *                      1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
 152  *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 153  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 154  * |s s s|                       ns                                |
 155  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 156  * |                        fraction                               |
 157  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 158  *
 159  * A frequency variable is a signed 64-bit fixed-point number in ns/s
 160  * and fraction. It represents the ns and fraction to be added to the
 161  * kernel time variable at each second. The maximum frequency offset is
 162  * about +-500000 ns/s and the resolution is about 2.3e-10 ns/s.
 163  *
 164  *                      1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
 165  *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 166  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 167  * |s s s s s s s s s s s s s|            ns/s                     |
 168  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 169  * |                        fraction                               |
 170  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 171  */
 172
 173 #define SHIFT_PLL       4
 174 #define SHIFT_FLL       2
 175
 176 static int time_state = TIME_OK;
 177 int time_status = STA_UNSYNC;
 178 static long time_tai;
 179 static long time_constant;
 180 static long time_precision = 1;
 181 static long time_maxerror = MAXPHASE / 1000;
 182 static unsigned long last_time_maxerror_update;
 183 long time_esterror = MAXPHASE / 1000;
 184 static long time_reftime;
 185 static l_fp time_offset;
 186 static l_fp time_freq;
 187 static int64_t time_adjtime;
 188 static int updated;
 189
 190 static lck_spin_t * ntp_lock;
 191 static lck_grp_t * ntp_lock_grp;
 192 static lck_attr_t * ntp_lock_attr;
 193 static lck_grp_attr_t   *ntp_lock_grp_attr;
 194
 195 #define NTP_LOCK(enable) \
 196                 enable =  ml_set_interrupts_enabled(FALSE); \
 197                 lck_spin_lock(ntp_lock);
 198
 199 #define NTP_UNLOCK(enable) \
 200                 lck_spin_unlock(ntp_lock);\
 201                 ml_set_interrupts_enabled(enable);
 202
 203 #define NTP_ASSERT_LOCKED()     LCK_SPIN_ASSERT(ntp_lock, LCK_ASSERT_OWNED)
 204
 205 static timer_call_data_t ntp_loop_update;
 206 static uint64_t ntp_loop_deadline;
 207 static uint32_t ntp_loop_active;
 208 static uint32_t ntp_loop_period;
 209 #define NTP_LOOP_PERIOD_INTERVAL (NSEC_PER_SEC) /*1 second interval*/
 210
 211 void ntp_init(void);
 212 static void hardupdate(long offset);
 213 static void ntp_gettime1(struct ntptimeval *ntvp);
 214 static bool ntp_is_time_error(int tsl);
 215
 216 static void ntp_loop_update_call(void);
 217 static void refresh_ntp_loop(void);
 218 static void start_ntp_loop(void);
 219
 220 #if DEVELOPMENT || DEBUG
 221 uint32_t g_should_log_clock_adjustments = 0;
 222 SYSCTL_INT(_kern, OID_AUTO, log_clock_adjustments, CTLFLAG_RW | CTLFLAG_LOCKED, &g_should_log_clock_adjustments, 0, "enable kernel clock adjustment logging");
 223 #endif
 224
 225 static bool
 226 ntp_is_time_error(int tsl)
 227 {
 228
 229         if (tsl & (STA_UNSYNC | STA_CLOCKERR))
 230                 return (true);
 231
 232         return (false);
 233 }
 234
 235 static void
 236 ntp_gettime1(struct ntptimeval *ntvp)
 237 {
 238         struct timespec atv;
 239
 240         NTP_ASSERT_LOCKED();
 241
 242         nanotime(&atv);
 243         ntvp->time.tv_sec = atv.tv_sec;
 244         ntvp->time.tv_nsec = atv.tv_nsec;
 245         if ((unsigned long)atv.tv_sec > last_time_maxerror_update) {
 246                 time_maxerror += (MAXFREQ / 1000)*(atv.tv_sec-last_time_maxerror_update);
 247                 last_time_maxerror_update = atv.tv_sec;
 248         }
 249         ntvp->maxerror = time_maxerror;
 250         ntvp->esterror = time_esterror;
 251         ntvp->tai = time_tai;
 252         ntvp->time_state = time_state;
 253
 254         if (ntp_is_time_error(time_status))
 255                 ntvp->time_state = TIME_ERROR;
 256 }
 257
 258 int
 259 ntp_gettime(struct proc *p, struct ntp_gettime_args *uap, __unused int32_t *retval)
 260 {
 261         struct ntptimeval ntv;
 262         int error;
 263         boolean_t enable;
 264
 265         NTP_LOCK(enable);
 266         ntp_gettime1(&ntv);
 267         NTP_UNLOCK(enable);
 268
 269         if (IS_64BIT_PROCESS(p)) {
 270                 struct user64_ntptimeval user_ntv = {};
 271                 user_ntv.time.tv_sec = ntv.time.tv_sec;
 272                 user_ntv.time.tv_nsec = ntv.time.tv_nsec;
 273                 user_ntv.maxerror = ntv.maxerror;
 274                 user_ntv.esterror = ntv.esterror;
 275                 user_ntv.tai = ntv.tai;
 276                 user_ntv.time_state = ntv.time_state;
 277                 error = copyout(&user_ntv, uap->ntvp, sizeof(user_ntv));
 278         } else {
 279                 struct user32_ntptimeval user_ntv = {};
 280                 user_ntv.time.tv_sec = ntv.time.tv_sec;
 281                 user_ntv.time.tv_nsec = ntv.time.tv_nsec;
 282                 user_ntv.maxerror = ntv.maxerror;
 283                 user_ntv.esterror = ntv.esterror;
 284                 user_ntv.tai = ntv.tai;
 285                 user_ntv.time_state = ntv.time_state;
 286                 error = copyout(&user_ntv, uap->ntvp, sizeof(user_ntv));
 287         }
 288
 289         if (error)
 290                 return error;
 291
 292         return ntv.time_state;
 293 }
 294
 295 int
 296 ntp_adjtime(struct proc *p, struct ntp_adjtime_args *uap, int32_t *retval)
 297 {
 298         struct timex ntv = {};
 299         long freq;
 300         unsigned int modes;
 301         int error, ret = 0;
 302         clock_sec_t sec;
 303         clock_usec_t microsecs;
 304         boolean_t enable;
 305
 306         if (IS_64BIT_PROCESS(p)) {
 307                 struct user64_timex user_ntv;
 308                 error = copyin(uap->tp, &user_ntv, sizeof(user_ntv));
 309                 ntv.modes = user_ntv.modes;
 310                 ntv.offset = user_ntv.offset;
 311                 ntv.freq = user_ntv.freq;
 312                 ntv.maxerror = user_ntv.maxerror;
 313                 ntv.esterror = user_ntv.esterror;
 314                 ntv.status = user_ntv.status;
 315                 ntv.constant = user_ntv.constant;
 316                 ntv.precision = user_ntv.precision;
 317                 ntv.tolerance = user_ntv.tolerance;
 318
 319         } else {
 320                 struct user32_timex user_ntv;
 321                 error = copyin(uap->tp, &user_ntv, sizeof(user_ntv));
 322                 ntv.modes = user_ntv.modes;
 323                 ntv.offset = user_ntv.offset;
 324                 ntv.freq = user_ntv.freq;
 325                 ntv.maxerror = user_ntv.maxerror;
 326                 ntv.esterror = user_ntv.esterror;
 327                 ntv.status = user_ntv.status;
 328                 ntv.constant = user_ntv.constant;
 329                 ntv.precision = user_ntv.precision;
 330                 ntv.tolerance = user_ntv.tolerance;
 331         }
 332         if (error)
 333                 return (error);
 334
 335 #if DEVELOPEMNT || DEBUG
 336         if (g_should_log_clock_adjustments) {
 337                 os_log(OS_LOG_DEFAULT, "%s: BEFORE modes %u offset %ld freq %ld status %d constant %ld time_adjtime %lld\n",
 338                        __func__, ntv.modes, ntv.offset, ntv.freq, ntv.status, ntv.constant, time_adjtime);
 339         }
 340 #endif
 341         /*
 342          * Update selected clock variables - only the superuser can
 343          * change anything. Note that there is no error checking here on
 344          * the assumption the superuser should know what it is doing.
 345          * Note that either the time constant or TAI offset are loaded
 346          * from the ntv.constant member, depending on the mode bits. If
 347          * the STA_PLL bit in the status word is cleared, the state and
 348          * status words are reset to the initial values at boot.
 349          */
 350         modes = ntv.modes;
 351         if (modes) {
 352                 /* Check that this task is entitled to set the time or it is root */
 353                 if (!IOTaskHasEntitlement(current_task(), SETTIME_ENTITLEMENT)) {
 354 #if CONFIG_MACF
 355                         error = mac_system_check_settime(kauth_cred_get());
 356                         if (error)
 357                                 return (error);
 358 #endif
 359                         if ((error = priv_check_cred(kauth_cred_get(), PRIV_ADJTIME, 0)))
 360                                 return (error);
 361
 362                 }
 363         }
 364
 365         NTP_LOCK(enable);
 366
 367         if (modes & MOD_MAXERROR) {
 368                 clock_gettimeofday(&sec, &microsecs);
 369                 time_maxerror = ntv.maxerror;
 370                 last_time_maxerror_update = sec;
 371         }
 372         if (modes & MOD_ESTERROR)
 373                 time_esterror = ntv.esterror;
 374         if (modes & MOD_STATUS) {
 375                 if (time_status & STA_PLL && !(ntv.status & STA_PLL)) {
 376                         time_state = TIME_OK;
 377                         time_status = STA_UNSYNC;
 378                 }
 379                 time_status &= STA_RONLY;
 380                 time_status |= ntv.status & ~STA_RONLY;
 381                 /*
 382                  * Nor PPS or leaps seconds are supported.
 383                  * Filter out unsupported bits.
 384                  */
 385                 time_status &= STA_SUPPORTED;
 386         }
 387         if (modes & MOD_TIMECONST) {
 388                 if (ntv.constant < 0)
 389                         time_constant = 0;
 390                 else if (ntv.constant > MAXTC)
 391                         time_constant = MAXTC;
 392                 else
 393                         time_constant = ntv.constant;
 394         }
 395         if (modes & MOD_TAI) {
 396                 if (ntv.constant > 0)
 397                         time_tai = ntv.constant;
 398         }
 399         if (modes & MOD_NANO)
 400                 time_status |= STA_NANO;
 401         if (modes & MOD_MICRO)
 402                 time_status &= ~STA_NANO;
 403         if (modes & MOD_CLKB)
 404                 time_status |= STA_CLK;
 405         if (modes & MOD_CLKA)
 406                 time_status &= ~STA_CLK;
 407         if (modes & MOD_FREQUENCY) {
 408                 freq = (ntv.freq * 1000LL) >> 16;
 409                 if (freq > MAXFREQ)
 410                         L_LINT(time_freq, MAXFREQ);
 411                 else if (freq < -MAXFREQ)
 412                         L_LINT(time_freq, -MAXFREQ);
 413                 else {
 414                         /*
 415                          * ntv.freq is [PPM * 2^16] = [us/s * 2^16]
 416                          * time_freq is [ns/s * 2^32]
 417                          */
 418                         time_freq = ntv.freq * 1000LL * 65536LL;
 419                 }
 420         }
 421         if (modes & MOD_OFFSET) {
 422                 if (time_status & STA_NANO)
 423                         hardupdate(ntv.offset);
 424                 else
 425                         hardupdate(ntv.offset * 1000);
 426         }
 427
 428         ret = ntp_is_time_error(time_status) ? TIME_ERROR : time_state;
 429
 430 #if DEVELOPEMNT || DEBUG
 431         if (g_should_log_clock_adjustments) {
 432                 os_log(OS_LOG_DEFAULT, "%s: AFTER modes %u offset %lld freq %lld status %d constant %ld time_adjtime %lld\n",
 433                        __func__, modes, time_offset, time_freq, time_status, time_constant, time_adjtime);
 434         }
 435 #endif
 436
 437         /*
 438          * Retrieve all clock variables. Note that the TAI offset is
 439          * returned only by ntp_gettime();
 440          */
 441         if (IS_64BIT_PROCESS(p)) {
 442                 struct user64_timex user_ntv = {};
 443
 444                 user_ntv.modes = modes;
 445                 if (time_status & STA_NANO)
 446                         user_ntv.offset = L_GINT(time_offset);
 447                 else
 448                         user_ntv.offset = L_GINT(time_offset) / 1000;
 449                 user_ntv.freq = L_GINT((time_freq / 1000LL) << 16);
 450                 user_ntv.maxerror = time_maxerror;
 451                 user_ntv.esterror = time_esterror;
 452                 user_ntv.status = time_status;
 453                 user_ntv.constant = time_constant;
 454                 if (time_status & STA_NANO)
 455                         user_ntv.precision = time_precision;
 456                 else
 457                         user_ntv.precision = time_precision / 1000;
 458                 user_ntv.tolerance = MAXFREQ * SCALE_PPM;
 459
 460                 /* unlock before copyout */
 461                 NTP_UNLOCK(enable);
 462
 463                 error = copyout(&user_ntv, uap->tp, sizeof(user_ntv));
 464
 465         }
 466         else{
 467                 struct user32_timex user_ntv = {};
 468
 469                 user_ntv.modes = modes;
 470                 if (time_status & STA_NANO)
 471                         user_ntv.offset = L_GINT(time_offset);
 472                 else
 473                         user_ntv.offset = L_GINT(time_offset) / 1000;
 474                 user_ntv.freq = L_GINT((time_freq / 1000LL) << 16);
 475                 user_ntv.maxerror = time_maxerror;
 476                 user_ntv.esterror = time_esterror;
 477                 user_ntv.status = time_status;
 478                 user_ntv.constant = time_constant;
 479                 if (time_status & STA_NANO)
 480                         user_ntv.precision = time_precision;
 481                 else
 482                         user_ntv.precision = time_precision / 1000;
 483                 user_ntv.tolerance = MAXFREQ * SCALE_PPM;
 484
 485                 /* unlock before copyout */
 486                 NTP_UNLOCK(enable);
 487
 488                 error = copyout(&user_ntv, uap->tp, sizeof(user_ntv));
 489         }
 490
 491         if (modes)
 492                 start_ntp_loop();
 493
 494         if (error == 0)
 495                 *retval = ret;
 496
 497         return (error);
 498 }
 499
 500 int64_t
 501 ntp_get_freq(void){
 502         return time_freq;
 503 }
 504
 505 /*
 506  * Compute the adjustment to add to the next second.
 507  */
 508 void
 509 ntp_update_second(int64_t *adjustment, clock_sec_t secs)
 510 {
 511         int tickrate;
 512         l_fp time_adj;
 513         l_fp ftemp, old_time_adjtime, old_offset;
 514
 515         NTP_ASSERT_LOCKED();
 516
 517         if (secs > last_time_maxerror_update) {
 518                 time_maxerror += (MAXFREQ / 1000)*(secs-last_time_maxerror_update);
 519                 last_time_maxerror_update = secs;
 520         }
 521
 522         old_offset = time_offset;
 523         old_time_adjtime = time_adjtime;
 524
 525         ftemp = time_offset;
 526         L_RSHIFT(ftemp, SHIFT_PLL + time_constant);
 527         time_adj = ftemp;
 528         L_SUB(time_offset, ftemp);
 529         L_ADD(time_adj, time_freq);
 530
 531         /*
 532          * Apply any correction from adjtime.  If more than one second
 533          * off we slew at a rate of 5ms/s (5000 PPM) else 500us/s (500PPM)
 534          * until the last second is slewed the final < 500 usecs.
 535          */
 536         if (time_adjtime != 0) {
 537                 if (time_adjtime > 1000000)
 538                         tickrate = 5000;
 539                 else if (time_adjtime < -1000000)
 540                         tickrate = -5000;
 541                 else if (time_adjtime > 500)
 542                         tickrate = 500;
 543                 else if (time_adjtime < -500)
 544                         tickrate = -500;
 545                 else
 546                         tickrate = time_adjtime;
 547                 time_adjtime -= tickrate;
 548                 L_LINT(ftemp, tickrate * 1000);
 549                 L_ADD(time_adj, ftemp);
 550         }
 551
 552         if (old_time_adjtime || ((time_offset || old_offset) && (time_offset != old_offset))) {
 553                 updated = 1;
 554         }
 555         else{
 556                 updated = 0;
 557         }
 558
 559 #if DEVELOPEMNT || DEBUG
 560         if (g_should_log_clock_adjustments) {
 561                 int64_t nano = (time_adj > 0)? time_adj >> 32 : -((-time_adj) >> 32);
 562                 int64_t frac = (time_adj > 0)? ((uint32_t) time_adj) : -((uint32_t) (-time_adj));
 563
 564                 os_log(OS_LOG_DEFAULT, "%s:AFTER offset %lld (%lld) freq %lld status %d "
 565                        "constant %ld time_adjtime %lld nano %lld frac %lld adj %lld\n",
 566                        __func__, time_offset, (time_offset > 0)? time_offset >> 32 : -((-time_offset) >> 32),
 567                        time_freq, time_status, time_constant, time_adjtime, nano, frac, time_adj);
 568         }
 569 #endif
 570
 571         *adjustment = time_adj;
 572 }
 573
 574 /*
 575  * hardupdate() - local clock update
 576  *
 577  * This routine is called by ntp_adjtime() when an offset is provided
 578  * to update the local clock phase and frequency.
 579  * The implementation is of an adaptive-parameter, hybrid
 580  * phase/frequency-lock loop (PLL/FLL). The routine computes new
 581  * time and frequency offset estimates for each call.
 582  * Presumably, calls to ntp_adjtime() occur only when the caller
 583  * believes the local clock is valid within some bound (+-128 ms with
 584  * NTP).
 585  *
 586  * For uncompensated quartz crystal oscillators and nominal update
 587  * intervals less than 256 s, operation should be in phase-lock mode,
 588  * where the loop is disciplined to phase. For update intervals greater
 589  * than 1024 s, operation should be in frequency-lock mode, where the
 590  * loop is disciplined to frequency. Between 256 s and 1024 s, the mode
 591  * is selected by the STA_MODE status bit.
 592  */
 593 static void
 594 hardupdate(offset)
 595         long offset;
 596 {
 597         long mtemp = 0;
 598         long time_monitor;
 599         clock_sec_t time_uptime;
 600         l_fp ftemp;
 601
 602         NTP_ASSERT_LOCKED();
 603
 604         if (!(time_status & STA_PLL))
 605                 return;
 606
 607         if (offset > MAXPHASE)
 608                 time_monitor = MAXPHASE;
 609         else if (offset < -MAXPHASE)
 610                 time_monitor = -MAXPHASE;
 611         else
 612                 time_monitor = offset;
 613         L_LINT(time_offset, time_monitor);
 614
 615         clock_get_calendar_uptime(&time_uptime);
 616
 617         if (time_status & STA_FREQHOLD || time_reftime == 0) {
 618                 time_reftime = time_uptime;
 619         }
 620
 621         mtemp = time_uptime - time_reftime;
 622         L_LINT(ftemp, time_monitor);
 623         L_RSHIFT(ftemp, (SHIFT_PLL + 2 + time_constant) << 1);
 624         L_MPY(ftemp, mtemp);
 625         L_ADD(time_freq, ftemp);
 626         time_status &= ~STA_MODE;
 627         if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp >
 628             MAXSEC)) {
 629                 L_LINT(ftemp, (time_monitor << 4) / mtemp);
 630                 L_RSHIFT(ftemp, SHIFT_FLL + 4);
 631                 L_ADD(time_freq, ftemp);
 632                 time_status |= STA_MODE;
 633         }
 634         time_reftime = time_uptime;
 635
 636         if (L_GINT(time_freq) > MAXFREQ)
 637                 L_LINT(time_freq, MAXFREQ);
 638         else if (L_GINT(time_freq) < -MAXFREQ)
 639                 L_LINT(time_freq, -MAXFREQ);
 640 }
 641
 642
 643 static int
 644 kern_adjtime(struct timeval *delta)
 645 {
 646         struct timeval atv;
 647         int64_t ltr, ltw;
 648         boolean_t enable;
 649
 650         if (delta == NULL)
 651                 return (EINVAL);
 652
 653         ltw = (int64_t)delta->tv_sec * (int64_t)USEC_PER_SEC + delta->tv_usec;
 654
 655         NTP_LOCK(enable);
 656         ltr = time_adjtime;
 657         time_adjtime = ltw;
 658 #if DEVELOPEMNT || DEBUG
 659         if (g_should_log_clock_adjustments) {
 660                 os_log(OS_LOG_DEFAULT, "%s:AFTER offset %lld freq %lld status %d constant %ld time_adjtime %lld\n",
 661                        __func__, time_offset, time_freq, time_status, time_constant, time_adjtime);
 662         }
 663 #endif
 664         NTP_UNLOCK(enable);
 665
 666         atv.tv_sec = ltr / (int64_t)USEC_PER_SEC;
 667         atv.tv_usec = ltr % (int64_t)USEC_PER_SEC;
 668         if (atv.tv_usec < 0) {
 669                 atv.tv_usec += (suseconds_t)USEC_PER_SEC;
 670                 atv.tv_sec--;
 671         }
 672
 673         *delta = atv;
 674
 675         start_ntp_loop();
 676
 677         return (0);
 678 }
 679
 680 int
 681 adjtime(struct proc *p, struct adjtime_args *uap, __unused int32_t *retval)
 682 {
 683
 684         struct timeval atv;
 685         int error;
 686
 687         /* Check that this task is entitled to set the time or it is root */
 688         if (!IOTaskHasEntitlement(current_task(), SETTIME_ENTITLEMENT)) {
 689
 690 #if CONFIG_MACF
 691                 error = mac_system_check_settime(kauth_cred_get());
 692                 if (error)
 693                         return (error);
 694 #endif
 695                 if ((error = priv_check_cred(kauth_cred_get(), PRIV_ADJTIME, 0)))
 696                         return (error);
 697         }
 698
 699         if (IS_64BIT_PROCESS(p)) {
 700                 struct user64_timeval user_atv;
 701                 error = copyin(uap->delta, &user_atv, sizeof(user_atv));
 702                 atv.tv_sec = user_atv.tv_sec;
 703                 atv.tv_usec = user_atv.tv_usec;
 704         } else {
 705                 struct user32_timeval user_atv;
 706                 error = copyin(uap->delta, &user_atv, sizeof(user_atv));
 707                 atv.tv_sec = user_atv.tv_sec;
 708                 atv.tv_usec = user_atv.tv_usec;
 709         }
 710         if (error)
 711                 return (error);
 712
 713         kern_adjtime(&atv);
 714
 715         if (uap->olddelta) {
 716                 if (IS_64BIT_PROCESS(p)) {
 717                         struct user64_timeval user_atv = {};
 718                         user_atv.tv_sec = atv.tv_sec;
 719                         user_atv.tv_usec = atv.tv_usec;
 720                         error = copyout(&user_atv, uap->olddelta, sizeof(user_atv));
 721                 } else {
 722                         struct user32_timeval user_atv = {};
 723                         user_atv.tv_sec = atv.tv_sec;
 724                         user_atv.tv_usec = atv.tv_usec;
 725                         error = copyout(&user_atv, uap->olddelta, sizeof(user_atv));
 726                 }
 727         }
 728
 729         return (error);
 730
 731 }
 732
 733 static void
 734 ntp_loop_update_call(void)
 735 {
 736         boolean_t enable;
 737
 738         NTP_LOCK(enable);
 739
 740         /*
 741          * Update the scale factor used by clock_calend.
 742          * NOTE: clock_update_calendar will call ntp_update_second to compute the next adjustment.
 743          */
 744         clock_update_calendar();
 745
 746         refresh_ntp_loop();
 747
 748         NTP_UNLOCK(enable);
 749 }
 750
 751 static void
 752 refresh_ntp_loop(void)
 753 {
 754
 755         NTP_ASSERT_LOCKED();
 756         if (--ntp_loop_active == 0) {
 757                 /*
 758                  * Activate the timer only if the next second adjustment might change.
 759                  * ntp_update_second checks it and sets updated accordingly.
 760                  */
 761                 if (updated) {
 762                         clock_deadline_for_periodic_event(ntp_loop_period, mach_absolute_time(), &ntp_loop_deadline);
 763
 764                         if (!timer_call_enter(&ntp_loop_update, ntp_loop_deadline, TIMER_CALL_SYS_CRITICAL))
 765                                         ntp_loop_active++;
 766                 }
 767         }
 768
 769 }
 770
 771 /*
 772  * This function triggers a timer that each second will calculate the adjustment to
 773  * provide to clock_calendar to scale the time (used by gettimeofday-family syscalls).
 774  * The periodic timer will stop when the adjustment will reach a stable value.
 775  */
 776 static void
 777 start_ntp_loop(void)
 778 {
 779         boolean_t enable;
 780
 781         NTP_LOCK(enable);
 782
 783         ntp_loop_deadline = mach_absolute_time() + ntp_loop_period;
 784
 785         if (!timer_call_enter(&ntp_loop_update, ntp_loop_deadline, TIMER_CALL_SYS_CRITICAL)) {
 786                         ntp_loop_active++;
 787         }
 788
 789         NTP_UNLOCK(enable);
 790 }
 791
 792
 793 static void
 794 init_ntp_loop(void)
 795 {
 796         uint64_t        abstime;
 797
 798         ntp_loop_active = 0;
 799         nanoseconds_to_absolutetime(NTP_LOOP_PERIOD_INTERVAL, &abstime);
 800         ntp_loop_period = (uint32_t)abstime;
 801         timer_call_setup(&ntp_loop_update, (timer_call_func_t)ntp_loop_update_call, NULL);
 802 }
 803
 804 void
 805 ntp_init(void)
 806 {
 807
 808         L_CLR(time_offset);
 809         L_CLR(time_freq);
 810
 811         ntp_lock_grp_attr = lck_grp_attr_alloc_init();
 812         ntp_lock_grp =  lck_grp_alloc_init("ntp_lock", ntp_lock_grp_attr);
 813         ntp_lock_attr = lck_attr_alloc_init();
 814         ntp_lock = lck_spin_alloc_init(ntp_lock_grp, ntp_lock_attr);
 815
 816         updated = 0;
 817
 818         init_ntp_loop();
 819 }
 820
 821 SYSINIT(ntpclocks, SI_SUB_CLOCKS, SI_ORDER_MIDDLE, ntp_init, NULL);