X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/4d15aeb193b2c68f1d38666c317f8d3734f5f083..5ba3f43ea354af8ad55bea84372a2bc834d8757c:/bsd/kern/kern_ntptime.c diff --git a/bsd/kern/kern_ntptime.c b/bsd/kern/kern_ntptime.c new file mode 100644 index 000000000..a922c3676 --- /dev/null +++ b/bsd/kern/kern_ntptime.c @@ -0,0 +1,782 @@ +/*- + *********************************************************************** + * * + * Copyright (c) David L. Mills 1993-2001 * + * * + * Permission to use, copy, modify, and distribute this software and * + * its documentation for any purpose and without fee is hereby * + * granted, provided that the above copyright notice appears in all * + * copies and that both the copyright notice and this permission * + * notice appear in supporting documentation, and that the name * + * University of Delaware not be used in advertising or publicity * + * pertaining to distribution of the software without specific, * + * written prior permission. The University of Delaware makes no * + * representations about the suitability this software for any * + * purpose. It is provided "as is" without express or implied * + * warranty. * + * * + **********************************************************************/ + + +/* + * Adapted from the original sources for FreeBSD and timecounters by: + * Poul-Henning Kamp . + * + * The 32bit version of the "LP" macros seems a bit past its "sell by" + * date so I have retained only the 64bit version and included it directly + * in this file. + * + * Only minor changes done to interface with the timecounters over in + * sys/kern/kern_clock.c. Some of the comments below may be (even more) + * confusing and/or plain wrong in that context. + */ + +/* + * Copyright (c) 2017 Apple Computer, Inc. All rights reserved. + * + * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ + * + * This file contains Original Code and/or Modifications of Original Code + * as defined in and that are subject to the Apple Public Source License + * Version 2.0 (the 'License'). You may not use this file except in + * compliance with the License. The rights granted to you under the License + * may not be used to create, or enable the creation or redistribution of, + * unlawful or unlicensed copies of an Apple operating system, or to + * circumvent, violate, or enable the circumvention or violation of, any + * terms of an Apple operating system software license agreement. + * + * Please obtain a copy of the License at + * http://www.opensource.apple.com/apsl/ and read it before using this file. + * + * The Original Code and all software distributed under the License are + * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER + * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, + * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. + * Please see the License for the specific language governing rights and + * limitations under the License. + * + * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#if CONFIG_MACF +#include +#endif +#include + +typedef int64_t l_fp; +#define L_ADD(v, u) ((v) += (u)) +#define L_SUB(v, u) ((v) -= (u)) +#define L_ADDHI(v, a) ((v) += (int64_t)(a) << 32) +#define L_NEG(v) ((v) = -(v)) +#define L_RSHIFT(v, n) \ + do { \ + if ((v) < 0) \ + (v) = -(-(v) >> (n)); \ + else \ + (v) = (v) >> (n); \ + } while (0) +#define L_MPY(v, a) ((v) *= (a)) +#define L_CLR(v) ((v) = 0) +#define L_ISNEG(v) ((v) < 0) +#define L_LINT(v, a) \ + do { \ + if ((a) > 0) \ + ((v) = (int64_t)(a) << 32); \ + else \ + ((v) = -((int64_t)(-(a)) << 32)); \ + } while (0) +#define L_GINT(v) ((v) < 0 ? -(-(v) >> 32) : (v) >> 32) + +/* + * Generic NTP kernel interface + * + * These routines constitute the Network Time Protocol (NTP) interfaces + * for user and daemon application programs. The ntp_gettime() routine + * provides the time, maximum error (synch distance) and estimated error + * (dispersion) to client user application programs. The ntp_adjtime() + * routine is used by the NTP daemon to adjust the calendar clock to an + * externally derived time. The time offset and related variables set by + * this routine are used by other routines in this module to adjust the + * phase and frequency of the clock discipline loop which controls the + * system clock. + * + * When the kernel time is reckoned directly in nanoseconds (NTP_NANO + * defined), the time at each tick interrupt is derived directly from + * the kernel time variable. When the kernel time is reckoned in + * microseconds, (NTP_NANO undefined), the time is derived from the + * kernel time variable together with a variable representing the + * leftover nanoseconds at the last tick interrupt. In either case, the + * current nanosecond time is reckoned from these values plus an + * interpolated value derived by the clock routines in another + * architecture-specific module. The interpolation can use either a + * dedicated counter or a processor cycle counter (PCC) implemented in + * some architectures. + * + */ +/* + * Phase/frequency-lock loop (PLL/FLL) definitions + * + * The nanosecond clock discipline uses two variable types, time + * variables and frequency variables. Both types are represented as 64- + * bit fixed-point quantities with the decimal point between two 32-bit + * halves. On a 32-bit machine, each half is represented as a single + * word and mathematical operations are done using multiple-precision + * arithmetic. On a 64-bit machine, ordinary computer arithmetic is + * used. + * + * A time variable is a signed 64-bit fixed-point number in ns and + * fraction. It represents the remaining time offset to be amortized + * over succeeding tick interrupts. The maximum time offset is about + * 0.5 s and the resolution is about 2.3e-10 ns. + * + * 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 + * 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 + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * |s s s| ns | + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * | fraction | + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * + * A frequency variable is a signed 64-bit fixed-point number in ns/s + * and fraction. It represents the ns and fraction to be added to the + * kernel time variable at each second. The maximum frequency offset is + * about +-500000 ns/s and the resolution is about 2.3e-10 ns/s. + * + * 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 + * 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 + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * |s s s s s s s s s s s s s| ns/s | + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * | fraction | + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + */ + +#define SHIFT_PLL 4 +#define SHIFT_FLL 2 + +static int time_state = TIME_OK; +int time_status = STA_UNSYNC; +static long time_tai; +static long time_constant; +static long time_precision = 1; +static long time_maxerror = MAXPHASE / 1000; +static unsigned long last_time_maxerror_update; +long time_esterror = MAXPHASE / 1000; +static long time_reftime; +static l_fp time_offset; +static l_fp time_freq; +static int64_t time_adjtime; +static int updated; + +static lck_spin_t * ntp_lock; +static lck_grp_t * ntp_lock_grp; +static lck_attr_t * ntp_lock_attr; +static lck_grp_attr_t *ntp_lock_grp_attr; + +#define NTP_LOCK(enable) \ + enable = ml_set_interrupts_enabled(FALSE); \ + lck_spin_lock(ntp_lock); + +#define NTP_UNLOCK(enable) \ + lck_spin_unlock(ntp_lock);\ + ml_set_interrupts_enabled(enable); + +#define NTP_ASSERT_LOCKED() LCK_SPIN_ASSERT(ntp_lock, LCK_ASSERT_OWNED) + +static timer_call_data_t ntp_loop_update; +static uint64_t ntp_loop_deadline; +static uint32_t ntp_loop_active; +static uint32_t ntp_loop_period; +#define NTP_LOOP_PERIOD_INTERVAL (NSEC_PER_SEC) /*1 second interval*/ + +void ntp_init(void); +static void hardupdate(long offset); +static void ntp_gettime1(struct ntptimeval *ntvp); +static bool ntp_is_time_error(int tsl); + +static void ntp_loop_update_call(void); +static void refresh_ntp_loop(void); +static void start_ntp_loop(void); + +static bool +ntp_is_time_error(int tsl) +{ + + if (tsl & (STA_UNSYNC | STA_CLOCKERR)) + return (true); + + return (false); +} + +static void +ntp_gettime1(struct ntptimeval *ntvp) +{ + struct timespec atv; + + NTP_ASSERT_LOCKED(); + + nanotime(&atv); + ntvp->time.tv_sec = atv.tv_sec; + ntvp->time.tv_nsec = atv.tv_nsec; + if ((unsigned long)atv.tv_sec > last_time_maxerror_update) { + time_maxerror += (MAXFREQ / 1000)*(atv.tv_sec-last_time_maxerror_update); + last_time_maxerror_update = atv.tv_sec; + } + ntvp->maxerror = time_maxerror; + ntvp->esterror = time_esterror; + ntvp->tai = time_tai; + ntvp->time_state = time_state; + + if (ntp_is_time_error(time_status)) + ntvp->time_state = TIME_ERROR; +} + +int +ntp_gettime(struct proc *p, struct ntp_gettime_args *uap, __unused int32_t *retval) +{ + struct ntptimeval ntv; + int error; + boolean_t enable; + + NTP_LOCK(enable); + ntp_gettime1(&ntv); + NTP_UNLOCK(enable); + + if (IS_64BIT_PROCESS(p)) { + struct user64_ntptimeval user_ntv; + user_ntv.time.tv_sec = ntv.time.tv_sec; + user_ntv.time.tv_nsec = ntv.time.tv_nsec; + user_ntv.maxerror = ntv.maxerror; + user_ntv.esterror = ntv.esterror; + user_ntv.tai = ntv.tai; + user_ntv.time_state = ntv.time_state; + error = copyout(&user_ntv, uap->ntvp, sizeof(user_ntv)); + } else { + struct user32_ntptimeval user_ntv; + user_ntv.time.tv_sec = ntv.time.tv_sec; + user_ntv.time.tv_nsec = ntv.time.tv_nsec; + user_ntv.maxerror = ntv.maxerror; + user_ntv.esterror = ntv.esterror; + user_ntv.tai = ntv.tai; + user_ntv.time_state = ntv.time_state; + error = copyout(&user_ntv, uap->ntvp, sizeof(user_ntv)); + } + + if (error) + return error; + + return ntv.time_state; +} + +int +ntp_adjtime(struct proc *p, struct ntp_adjtime_args *uap, __unused int32_t *retval) +{ + struct timex ntv; + long freq; + int modes; + int error, ret = 0; + clock_sec_t sec; + clock_usec_t microsecs; + boolean_t enable; + + if (IS_64BIT_PROCESS(p)) { + struct user64_timex user_ntv; + error = copyin(uap->tp, &user_ntv, sizeof(user_ntv)); + ntv.modes = user_ntv.modes; + ntv.offset = user_ntv.offset; + ntv.freq = user_ntv.freq; + ntv.maxerror = user_ntv.maxerror; + ntv.esterror = user_ntv.esterror; + ntv.status = user_ntv.status; + ntv.constant = user_ntv.constant; + ntv.precision = user_ntv.precision; + ntv.tolerance = user_ntv.tolerance; + + } else { + struct user32_timex user_ntv; + error = copyin(uap->tp, &user_ntv, sizeof(user_ntv)); + ntv.modes = user_ntv.modes; + ntv.offset = user_ntv.offset; + ntv.freq = user_ntv.freq; + ntv.maxerror = user_ntv.maxerror; + ntv.esterror = user_ntv.esterror; + ntv.status = user_ntv.status; + ntv.constant = user_ntv.constant; + ntv.precision = user_ntv.precision; + ntv.tolerance = user_ntv.tolerance; + } + if (error) + return (error); + + /* + * Update selected clock variables - only the superuser can + * change anything. Note that there is no error checking here on + * the assumption the superuser should know what it is doing. + * Note that either the time constant or TAI offset are loaded + * from the ntv.constant member, depending on the mode bits. If + * the STA_PLL bit in the status word is cleared, the state and + * status words are reset to the initial values at boot. + */ + modes = ntv.modes; + if (modes) { + /* Check that this task is entitled to set the time or it is root */ + if (!IOTaskHasEntitlement(current_task(), SETTIME_ENTITLEMENT)) { +#if CONFIG_MACF + error = mac_system_check_settime(kauth_cred_get()); + if (error) + return (error); +#endif + if ((error = priv_check_cred(kauth_cred_get(), PRIV_ADJTIME, 0))) + return (error); + + } + } + + NTP_LOCK(enable); + + if (modes & MOD_MAXERROR) { + clock_gettimeofday(&sec, µsecs); + time_maxerror = ntv.maxerror; + last_time_maxerror_update = sec; + } + if (modes & MOD_ESTERROR) + time_esterror = ntv.esterror; + if (modes & MOD_STATUS) { + if (time_status & STA_PLL && !(ntv.status & STA_PLL)) { + time_state = TIME_OK; + time_status = STA_UNSYNC; + } + time_status &= STA_RONLY; + time_status |= ntv.status & ~STA_RONLY; + /* + * Nor PPS or leaps seconds are supported. + * Filter out unsupported bits. + */ + time_status &= STA_SUPPORTED; + } + if (modes & MOD_TIMECONST) { + if (ntv.constant < 0) + time_constant = 0; + else if (ntv.constant > MAXTC) + time_constant = MAXTC; + else + time_constant = ntv.constant; + } + if (modes & MOD_TAI) { + if (ntv.constant > 0) + time_tai = ntv.constant; + } + if (modes & MOD_NANO) + time_status |= STA_NANO; + if (modes & MOD_MICRO) + time_status &= ~STA_NANO; + if (modes & MOD_CLKB) + time_status |= STA_CLK; + if (modes & MOD_CLKA) + time_status &= ~STA_CLK; + if (modes & MOD_FREQUENCY) { + freq = (ntv.freq * 1000LL) >> 16; + if (freq > MAXFREQ) + L_LINT(time_freq, MAXFREQ); + else if (freq < -MAXFREQ) + L_LINT(time_freq, -MAXFREQ); + else { + /* + * ntv.freq is [PPM * 2^16] = [us/s * 2^16] + * time_freq is [ns/s * 2^32] + */ + time_freq = ntv.freq * 1000LL * 65536LL; + } + } + if (modes & MOD_OFFSET) { + if (time_status & STA_NANO) + hardupdate(ntv.offset); + else + hardupdate(ntv.offset * 1000); + } + + ret = ntp_is_time_error(time_status) ? TIME_ERROR : time_state; + + /* + * Retrieve all clock variables. Note that the TAI offset is + * returned only by ntp_gettime(); + */ + if (IS_64BIT_PROCESS(p)) { + struct user64_timex user_ntv; + + if (time_status & STA_NANO) + user_ntv.offset = L_GINT(time_offset); + else + user_ntv.offset = L_GINT(time_offset) / 1000; + user_ntv.freq = L_GINT((time_freq / 1000LL) << 16); + user_ntv.maxerror = time_maxerror; + user_ntv.esterror = time_esterror; + user_ntv.status = time_status; + user_ntv.constant = time_constant; + if (time_status & STA_NANO) + user_ntv.precision = time_precision; + else + user_ntv.precision = time_precision / 1000; + user_ntv.tolerance = MAXFREQ * SCALE_PPM; + + /* unlock before copyout */ + NTP_UNLOCK(enable); + + error = copyout(&user_ntv, uap->tp, sizeof(user_ntv)); + + } + else{ + struct user32_timex user_ntv; + + if (time_status & STA_NANO) + user_ntv.offset = L_GINT(time_offset); + else + user_ntv.offset = L_GINT(time_offset) / 1000; + user_ntv.freq = L_GINT((time_freq / 1000LL) << 16); + user_ntv.maxerror = time_maxerror; + user_ntv.esterror = time_esterror; + user_ntv.status = time_status; + user_ntv.constant = time_constant; + if (time_status & STA_NANO) + user_ntv.precision = time_precision; + else + user_ntv.precision = time_precision / 1000; + user_ntv.tolerance = MAXFREQ * SCALE_PPM; + + /* unlock before copyout */ + NTP_UNLOCK(enable); + + error = copyout(&user_ntv, uap->tp, sizeof(user_ntv)); + } + + if (modes) + start_ntp_loop(); + + if (error == 0) + *retval = ret; + + return (error); +} + +int64_t +ntp_get_freq(void){ + return time_freq; +} + +/* + * Compute the adjustment to add to the next second. + */ +void +ntp_update_second(int64_t *adjustment, clock_sec_t secs) +{ + int tickrate; + l_fp time_adj; + l_fp ftemp, old_time_adjtime, old_offset; + + NTP_ASSERT_LOCKED(); + + if (secs > last_time_maxerror_update) { + time_maxerror += (MAXFREQ / 1000)*(secs-last_time_maxerror_update); + last_time_maxerror_update = secs; + } + + old_offset = time_offset; + old_time_adjtime = time_adjtime; + + ftemp = time_offset; + L_RSHIFT(ftemp, SHIFT_PLL + time_constant); + time_adj = ftemp; + L_SUB(time_offset, ftemp); + L_ADD(time_adj, time_freq); + + /* + * Apply any correction from adjtime. If more than one second + * off we slew at a rate of 5ms/s (5000 PPM) else 500us/s (500PPM) + * until the last second is slewed the final < 500 usecs. + */ + if (time_adjtime != 0) { + if (time_adjtime > 1000000) + tickrate = 5000; + else if (time_adjtime < -1000000) + tickrate = -5000; + else if (time_adjtime > 500) + tickrate = 500; + else if (time_adjtime < -500) + tickrate = -500; + else + tickrate = time_adjtime; + time_adjtime -= tickrate; + L_LINT(ftemp, tickrate * 1000); + L_ADD(time_adj, ftemp); + } + + if (old_time_adjtime || ((time_offset || old_offset) && (time_offset != old_offset))) { + updated = 1; + } + else{ + updated = 0; + } + + *adjustment = time_adj; +} + +/* + * hardupdate() - local clock update + * + * This routine is called by ntp_adjtime() when an offset is provided + * to update the local clock phase and frequency. + * The implementation is of an adaptive-parameter, hybrid + * phase/frequency-lock loop (PLL/FLL). The routine computes new + * time and frequency offset estimates for each call. + * Presumably, calls to ntp_adjtime() occur only when the caller + * believes the local clock is valid within some bound (+-128 ms with + * NTP). + * + * For uncompensated quartz crystal oscillators and nominal update + * intervals less than 256 s, operation should be in phase-lock mode, + * where the loop is disciplined to phase. For update intervals greater + * than 1024 s, operation should be in frequency-lock mode, where the + * loop is disciplined to frequency. Between 256 s and 1024 s, the mode + * is selected by the STA_MODE status bit. + */ +static void +hardupdate(offset) + long offset; +{ + long mtemp = 0; + long time_monitor; + clock_sec_t time_uptime; + l_fp ftemp; + + NTP_ASSERT_LOCKED(); + + if (!(time_status & STA_PLL)) + return; + + if (offset > MAXPHASE) + time_monitor = MAXPHASE; + else if (offset < -MAXPHASE) + time_monitor = -MAXPHASE; + else + time_monitor = offset; + L_LINT(time_offset, time_monitor); + + clock_get_calendar_uptime(&time_uptime); + + if (time_status & STA_FREQHOLD || time_reftime == 0) { + time_reftime = time_uptime; + } + + mtemp = time_uptime - time_reftime; + L_LINT(ftemp, time_monitor); + L_RSHIFT(ftemp, (SHIFT_PLL + 2 + time_constant) << 1); + L_MPY(ftemp, mtemp); + L_ADD(time_freq, ftemp); + time_status &= ~STA_MODE; + if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > + MAXSEC)) { + L_LINT(ftemp, (time_monitor << 4) / mtemp); + L_RSHIFT(ftemp, SHIFT_FLL + 4); + L_ADD(time_freq, ftemp); + time_status |= STA_MODE; + } + time_reftime = time_uptime; + + if (L_GINT(time_freq) > MAXFREQ) + L_LINT(time_freq, MAXFREQ); + else if (L_GINT(time_freq) < -MAXFREQ) + L_LINT(time_freq, -MAXFREQ); +} + + +static int +kern_adjtime(struct timeval *delta) +{ + struct timeval atv; + int64_t ltr, ltw; + boolean_t enable; + + if (delta == NULL) + return (EINVAL); + + ltw = (int64_t)delta->tv_sec * (int64_t)USEC_PER_SEC + delta->tv_usec; + + NTP_LOCK(enable); + ltr = time_adjtime; + time_adjtime = ltw; + NTP_UNLOCK(enable); + + atv.tv_sec = ltr / (int64_t)USEC_PER_SEC; + atv.tv_usec = ltr % (int64_t)USEC_PER_SEC; + if (atv.tv_usec < 0) { + atv.tv_usec += (suseconds_t)USEC_PER_SEC; + atv.tv_sec--; + } + + *delta = atv; + + start_ntp_loop(); + + return (0); +} + +int +adjtime(struct proc *p, struct adjtime_args *uap, __unused int32_t *retval) +{ + + struct timeval atv; + int error; + + /* Check that this task is entitled to set the time or it is root */ + if (!IOTaskHasEntitlement(current_task(), SETTIME_ENTITLEMENT)) { + +#if CONFIG_MACF + error = mac_system_check_settime(kauth_cred_get()); + if (error) + return (error); +#endif + if ((error = priv_check_cred(kauth_cred_get(), PRIV_ADJTIME, 0))) + return (error); + } + + if (IS_64BIT_PROCESS(p)) { + struct user64_timeval user_atv; + error = copyin(uap->delta, &user_atv, sizeof(user_atv)); + atv.tv_sec = user_atv.tv_sec; + atv.tv_usec = user_atv.tv_usec; + } else { + struct user32_timeval user_atv; + error = copyin(uap->delta, &user_atv, sizeof(user_atv)); + atv.tv_sec = user_atv.tv_sec; + atv.tv_usec = user_atv.tv_usec; + } + if (error) + return (error); + + kern_adjtime(&atv); + + if (uap->olddelta) { + if (IS_64BIT_PROCESS(p)) { + struct user64_timeval user_atv; + user_atv.tv_sec = atv.tv_sec; + user_atv.tv_usec = atv.tv_usec; + error = copyout(&user_atv, uap->olddelta, sizeof(user_atv)); + } else { + struct user32_timeval user_atv; + user_atv.tv_sec = atv.tv_sec; + user_atv.tv_usec = atv.tv_usec; + error = copyout(&user_atv, uap->olddelta, sizeof(user_atv)); + } + } + + return (error); + +} + +static void +ntp_loop_update_call(void) +{ + boolean_t enable; + + NTP_LOCK(enable); + + /* + * Update the scale factor used by clock_calend. + * NOTE: clock_update_calendar will call ntp_update_second to compute the next adjustment. + */ + clock_update_calendar(); + + refresh_ntp_loop(); + + NTP_UNLOCK(enable); +} + +static void +refresh_ntp_loop(void) +{ + + NTP_ASSERT_LOCKED(); + if (--ntp_loop_active == 0) { + /* + * Activate the timer only if the next second adjustment might change. + * ntp_update_second checks it and sets updated accordingly. + */ + if (updated) { + clock_deadline_for_periodic_event(ntp_loop_period, mach_absolute_time(), &ntp_loop_deadline); + + if (!timer_call_enter(&ntp_loop_update, ntp_loop_deadline, TIMER_CALL_SYS_CRITICAL)) + ntp_loop_active++; + } + } + +} + +/* + * This function triggers a timer that each second will calculate the adjustment to + * provide to clock_calendar to scale the time (used by gettimeofday-family syscalls). + * The periodic timer will stop when the adjustment will reach a stable value. + */ +static void +start_ntp_loop(void) +{ + boolean_t enable; + + NTP_LOCK(enable); + + ntp_loop_deadline = mach_absolute_time() + ntp_loop_period; + + if (!timer_call_enter(&ntp_loop_update, ntp_loop_deadline, TIMER_CALL_SYS_CRITICAL)) { + ntp_loop_active++; + } + + NTP_UNLOCK(enable); +} + + +static void +init_ntp_loop(void) +{ + uint64_t abstime; + + ntp_loop_active = 0; + nanoseconds_to_absolutetime(NTP_LOOP_PERIOD_INTERVAL, &abstime); + ntp_loop_period = (uint32_t)abstime; + timer_call_setup(&ntp_loop_update, (timer_call_func_t)ntp_loop_update_call, NULL); +} + +void +ntp_init(void) +{ + + L_CLR(time_offset); + L_CLR(time_freq); + + ntp_lock_grp_attr = lck_grp_attr_alloc_init(); + ntp_lock_grp = lck_grp_alloc_init("ntp_lock", ntp_lock_grp_attr); + ntp_lock_attr = lck_attr_alloc_init(); + ntp_lock = lck_spin_alloc_init(ntp_lock_grp, ntp_lock_attr); + + updated = 0; + + init_ntp_loop(); +} + +SYSINIT(ntpclocks, SI_SUB_CLOCKS, SI_ORDER_MIDDLE, ntp_init, NULL);