static long time_constant = 2;
/* maximum error (usecs): */
-long time_maxerror = NTP_PHASE_LIMIT;
+static long time_maxerror = NTP_PHASE_LIMIT;
/* estimated error (usecs): */
-long time_esterror = NTP_PHASE_LIMIT;
+static long time_esterror = NTP_PHASE_LIMIT;
/* frequency offset (scaled nsecs/secs): */
static s64 time_freq;
/* time at last adjustment (secs): */
static long time_reftime;
-long time_adjust;
+static long time_adjust;
-static long ntp_tick_adj;
+/* constant (boot-param configurable) NTP tick adjustment (upscaled) */
+static s64 ntp_tick_adj;
/*
* NTP methods:
*/
+/*
+ * Update (tick_length, tick_length_base, tick_nsec), based
+ * on (tick_usec, ntp_tick_adj, time_freq):
+ */
static void ntp_update_frequency(void)
{
- u64 old_tick_length_base = tick_length_base;
- u64 second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ)
- << NTP_SCALE_SHIFT;
- second_length += (s64)ntp_tick_adj << NTP_SCALE_SHIFT;
- second_length += time_freq;
+ u64 second_length;
+ u64 new_base;
+
+ second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ)
+ << NTP_SCALE_SHIFT;
- tick_length_base = second_length;
+ second_length += ntp_tick_adj;
+ second_length += time_freq;
- tick_nsec = div_u64(second_length, HZ) >> NTP_SCALE_SHIFT;
- tick_length_base = div_u64(tick_length_base, NTP_INTERVAL_FREQ);
+ tick_nsec = div_u64(second_length, HZ) >> NTP_SCALE_SHIFT;
+ new_base = div_u64(second_length, NTP_INTERVAL_FREQ);
/*
* Don't wait for the next second_overflow, apply
- * the change to the tick length immediately
+ * the change to the tick length immediately:
*/
- tick_length += tick_length_base - old_tick_length_base;
+ tick_length += new_base - tick_length_base;
+ tick_length_base = new_base;
+}
+
+static inline s64 ntp_update_offset_fll(s64 offset64, long secs)
+{
+ time_status &= ~STA_MODE;
+
+ if (secs < MINSEC)
+ return 0;
+
+ if (!(time_status & STA_FLL) && (secs <= MAXSEC))
+ return 0;
+
+ time_status |= STA_MODE;
+
+ return div_s64(offset64 << (NTP_SCALE_SHIFT - SHIFT_FLL), secs);
}
static void ntp_update_offset(long offset)
{
- long mtemp;
s64 freq_adj;
+ s64 offset64;
+ long secs;
if (!(time_status & STA_PLL))
return;
* Select how the frequency is to be controlled
* and in which mode (PLL or FLL).
*/
- if (time_status & STA_FREQHOLD || time_reftime == 0)
- time_reftime = xtime.tv_sec;
- mtemp = xtime.tv_sec - time_reftime;
- time_reftime = xtime.tv_sec;
+ secs = get_seconds() - time_reftime;
+ if (unlikely(time_status & STA_FREQHOLD))
+ secs = 0;
- freq_adj = (s64)offset * mtemp;
- freq_adj <<= NTP_SCALE_SHIFT - 2 * (SHIFT_PLL + 2 + time_constant);
- time_status &= ~STA_MODE;
- if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > MAXSEC)) {
- freq_adj += div_s64((s64)offset << (NTP_SCALE_SHIFT - SHIFT_FLL),
- mtemp);
- time_status |= STA_MODE;
- }
- freq_adj += time_freq;
- freq_adj = min(freq_adj, MAXFREQ_SCALED);
- time_freq = max(freq_adj, -MAXFREQ_SCALED);
+ time_reftime = get_seconds();
+
+ offset64 = offset;
+ freq_adj = ntp_update_offset_fll(offset64, secs);
+
+ /*
+ * Clamp update interval to reduce PLL gain with low
+ * sampling rate (e.g. intermittent network connection)
+ * to avoid instability.
+ */
+ if (unlikely(secs > 1 << (SHIFT_PLL + 1 + time_constant)))
+ secs = 1 << (SHIFT_PLL + 1 + time_constant);
+
+ freq_adj += (offset64 * secs) <<
+ (NTP_SCALE_SHIFT - 2 * (SHIFT_PLL + 2 + time_constant));
- time_offset = div_s64((s64)offset << NTP_SCALE_SHIFT, NTP_INTERVAL_FREQ);
+ freq_adj = min(freq_adj + time_freq, MAXFREQ_SCALED);
+
+ time_freq = max(freq_adj, -MAXFREQ_SCALED);
+
+ time_offset = div_s64(offset64 << NTP_SCALE_SHIFT, NTP_INTERVAL_FREQ);
}
/**
case TIME_OK:
break;
case TIME_INS:
- xtime.tv_sec--;
- wall_to_monotonic.tv_sec++;
+ timekeeping_leap_insert(-1);
time_state = TIME_OOP;
printk(KERN_NOTICE
"Clock: inserting leap second 23:59:60 UTC\n");
res = HRTIMER_RESTART;
break;
case TIME_DEL:
- xtime.tv_sec++;
+ timekeeping_leap_insert(1);
time_tai--;
- wall_to_monotonic.tv_sec--;
time_state = TIME_WAIT;
printk(KERN_NOTICE
"Clock: deleting leap second 23:59:59 UTC\n");
time_state = TIME_OK;
break;
}
- update_vsyscall(&xtime, clock);
write_sequnlock(&xtime_lock);
*/
void second_overflow(void)
{
- s64 time_adj;
+ s64 delta;
/* Bump the maxerror field */
time_maxerror += MAXFREQ / NSEC_PER_USEC;
* Compute the phase adjustment for the next second. The offset is
* reduced by a fixed factor times the time constant.
*/
- tick_length = tick_length_base;
- time_adj = shift_right(time_offset, SHIFT_PLL + time_constant);
- time_offset -= time_adj;
- tick_length += time_adj;
+ tick_length = tick_length_base;
+
+ delta = shift_right(time_offset, SHIFT_PLL + time_constant);
+ time_offset -= delta;
+ tick_length += delta;
if (!time_adjust)
return;
static inline void notify_cmos_timer(void) { }
#endif
+/*
+ * Start the leap seconds timer:
+ */
+static inline void ntp_start_leap_timer(struct timespec *ts)
+{
+ long now = ts->tv_sec;
+
+ if (time_status & STA_INS) {
+ time_state = TIME_INS;
+ now += 86400 - now % 86400;
+ hrtimer_start(&leap_timer, ktime_set(now, 0), HRTIMER_MODE_ABS);
+
+ return;
+ }
+
+ if (time_status & STA_DEL) {
+ time_state = TIME_DEL;
+ now += 86400 - (now + 1) % 86400;
+ hrtimer_start(&leap_timer, ktime_set(now, 0), HRTIMER_MODE_ABS);
+ }
+}
+
+/*
+ * Propagate a new txc->status value into the NTP state:
+ */
+static inline void process_adj_status(struct timex *txc, struct timespec *ts)
+{
+ if ((time_status & STA_PLL) && !(txc->status & STA_PLL)) {
+ time_state = TIME_OK;
+ time_status = STA_UNSYNC;
+ }
+
+ /*
+ * If we turn on PLL adjustments then reset the
+ * reference time to current time.
+ */
+ if (!(time_status & STA_PLL) && (txc->status & STA_PLL))
+ time_reftime = get_seconds();
+
+ /* only set allowed bits */
+ time_status &= STA_RONLY;
+ time_status |= txc->status & ~STA_RONLY;
+
+ switch (time_state) {
+ case TIME_OK:
+ ntp_start_leap_timer(ts);
+ break;
+ case TIME_INS:
+ case TIME_DEL:
+ time_state = TIME_OK;
+ ntp_start_leap_timer(ts);
+ case TIME_WAIT:
+ if (!(time_status & (STA_INS | STA_DEL)))
+ time_state = TIME_OK;
+ break;
+ case TIME_OOP:
+ hrtimer_restart(&leap_timer);
+ break;
+ }
+}
+/*
+ * Called with the xtime lock held, so we can access and modify
+ * all the global NTP state:
+ */
+static inline void process_adjtimex_modes(struct timex *txc, struct timespec *ts)
+{
+ if (txc->modes & ADJ_STATUS)
+ process_adj_status(txc, ts);
+
+ if (txc->modes & ADJ_NANO)
+ time_status |= STA_NANO;
+
+ if (txc->modes & ADJ_MICRO)
+ time_status &= ~STA_NANO;
+
+ if (txc->modes & ADJ_FREQUENCY) {
+ time_freq = txc->freq * PPM_SCALE;
+ time_freq = min(time_freq, MAXFREQ_SCALED);
+ time_freq = max(time_freq, -MAXFREQ_SCALED);
+ }
+
+ if (txc->modes & ADJ_MAXERROR)
+ time_maxerror = txc->maxerror;
+
+ if (txc->modes & ADJ_ESTERROR)
+ time_esterror = txc->esterror;
+
+ if (txc->modes & ADJ_TIMECONST) {
+ time_constant = txc->constant;
+ if (!(time_status & STA_NANO))
+ time_constant += 4;
+ time_constant = min(time_constant, (long)MAXTC);
+ time_constant = max(time_constant, 0l);
+ }
+
+ if (txc->modes & ADJ_TAI && txc->constant > 0)
+ time_tai = txc->constant;
+
+ if (txc->modes & ADJ_OFFSET)
+ ntp_update_offset(txc->offset);
+
+ if (txc->modes & ADJ_TICK)
+ tick_usec = txc->tick;
+
+ if (txc->modes & (ADJ_TICK|ADJ_FREQUENCY|ADJ_OFFSET))
+ ntp_update_frequency();
+}
+
/*
* adjtimex mainly allows reading (and writing, if superuser) of
* kernel time-keeping variables. used by xntpd.
if (txc->modes & ADJ_TICK &&
(txc->tick < 900000/USER_HZ ||
txc->tick > 1100000/USER_HZ))
- return -EINVAL;
+ return -EINVAL;
if (txc->modes & ADJ_STATUS && time_state != TIME_OK)
hrtimer_cancel(&leap_timer);
write_seqlock_irq(&xtime_lock);
- /* If there are input parameters, then process them */
if (txc->modes & ADJ_ADJTIME) {
long save_adjust = time_adjust;
ntp_update_frequency();
}
txc->offset = save_adjust;
- goto adj_done;
- }
- if (txc->modes) {
- long sec;
-
- if (txc->modes & ADJ_STATUS) {
- if ((time_status & STA_PLL) &&
- !(txc->status & STA_PLL)) {
- time_state = TIME_OK;
- time_status = STA_UNSYNC;
- }
- /* only set allowed bits */
- time_status &= STA_RONLY;
- time_status |= txc->status & ~STA_RONLY;
-
- switch (time_state) {
- case TIME_OK:
- start_timer:
- sec = ts.tv_sec;
- if (time_status & STA_INS) {
- time_state = TIME_INS;
- sec += 86400 - sec % 86400;
- hrtimer_start(&leap_timer, ktime_set(sec, 0), HRTIMER_MODE_ABS);
- } else if (time_status & STA_DEL) {
- time_state = TIME_DEL;
- sec += 86400 - (sec + 1) % 86400;
- hrtimer_start(&leap_timer, ktime_set(sec, 0), HRTIMER_MODE_ABS);
- }
- break;
- case TIME_INS:
- case TIME_DEL:
- time_state = TIME_OK;
- goto start_timer;
- break;
- case TIME_WAIT:
- if (!(time_status & (STA_INS | STA_DEL)))
- time_state = TIME_OK;
- break;
- case TIME_OOP:
- hrtimer_restart(&leap_timer);
- break;
- }
- }
-
- if (txc->modes & ADJ_NANO)
- time_status |= STA_NANO;
- if (txc->modes & ADJ_MICRO)
- time_status &= ~STA_NANO;
-
- if (txc->modes & ADJ_FREQUENCY) {
- time_freq = (s64)txc->freq * PPM_SCALE;
- time_freq = min(time_freq, MAXFREQ_SCALED);
- time_freq = max(time_freq, -MAXFREQ_SCALED);
- }
-
- if (txc->modes & ADJ_MAXERROR)
- time_maxerror = txc->maxerror;
- if (txc->modes & ADJ_ESTERROR)
- time_esterror = txc->esterror;
-
- if (txc->modes & ADJ_TIMECONST) {
- time_constant = txc->constant;
- if (!(time_status & STA_NANO))
- time_constant += 4;
- time_constant = min(time_constant, (long)MAXTC);
- time_constant = max(time_constant, 0l);
- }
-
- if (txc->modes & ADJ_TAI && txc->constant > 0)
- time_tai = txc->constant;
+ } else {
- if (txc->modes & ADJ_OFFSET)
- ntp_update_offset(txc->offset);
- if (txc->modes & ADJ_TICK)
- tick_usec = txc->tick;
+ /* If there are input parameters, then process them: */
+ if (txc->modes)
+ process_adjtimex_modes(txc, &ts);
- if (txc->modes & (ADJ_TICK|ADJ_FREQUENCY|ADJ_OFFSET))
- ntp_update_frequency();
- }
-
- txc->offset = shift_right(time_offset * NTP_INTERVAL_FREQ,
+ txc->offset = shift_right(time_offset * NTP_INTERVAL_FREQ,
NTP_SCALE_SHIFT);
- if (!(time_status & STA_NANO))
- txc->offset /= NSEC_PER_USEC;
+ if (!(time_status & STA_NANO))
+ txc->offset /= NSEC_PER_USEC;
+ }
-adj_done:
result = time_state; /* mostly `TIME_OK' */
if (time_status & (STA_UNSYNC|STA_CLOCKERR))
result = TIME_ERROR;
txc->freq = shift_right((time_freq >> PPM_SCALE_INV_SHIFT) *
- (s64)PPM_SCALE_INV, NTP_SCALE_SHIFT);
+ PPM_SCALE_INV, NTP_SCALE_SHIFT);
txc->maxerror = time_maxerror;
txc->esterror = time_esterror;
txc->status = time_status;
txc->calcnt = 0;
txc->errcnt = 0;
txc->stbcnt = 0;
+
write_sequnlock_irq(&xtime_lock);
txc->time.tv_sec = ts.tv_sec;
static int __init ntp_tick_adj_setup(char *str)
{
ntp_tick_adj = simple_strtol(str, NULL, 0);
+ ntp_tick_adj <<= NTP_SCALE_SHIFT;
+
return 1;
}
Code Review / linux-2.6.git / blobdiff