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Date: Fri, 14 Mar 2008 13:36:51 -0700
From: john stultz <johnstul@...ibm.com>
To: zippel@...ux-m68k.org
Cc: linux-kernel@...r.kernel.org, akpm@...ux-foundation.org
Subject: Re: [PATCH 2/8] NTP4 user space bits update
On Fri, 2008-03-14 at 19:40 +0100, zippel@...ux-m68k.org wrote:
> plain text document attachment (ntp4_user)
> This adds a few more things from the ntp nanokernel related to user
> space. It's now possible to select the resolution used of some values
> via STA_NANO and the kernel reports in which mode it works (pll/fll).
>
> If some values for adjtimex() are outside the acceptable range, they are
> now simply normalized instead of letting the syscall fail.
> I removed MOD_CLKA/MOD_CLKB as the mapping didn't really makes any
> sense, the kernel doesn't support setting the clock.
>
> Signed-off-by: Roman Zippel <zippel@...ux-m68k.org>
I've not looked up the new NTP4-ims, but few comments below.
> ---
> include/linux/timex.h | 12 ++++--
> kernel/time/ntp.c | 91 +++++++++++++++++++++++++-------------------------
> 2 files changed, 56 insertions(+), 47 deletions(-)
>
> Index: linux-2.6/include/linux/timex.h
> ===================================================================
> --- linux-2.6.orig/include/linux/timex.h 2008-03-13 10:42:20.000000000 +0100
> +++ linux-2.6/include/linux/timex.h 2008-03-13 10:48:59.000000000 +0100
> @@ -58,6 +58,8 @@
>
> #include <asm/param.h>
>
> +#define NTP_API 4 /* NTP API version */
> +
> /*
> * SHIFT_KG and SHIFT_KF establish the damping of the PLL and are chosen
> * for a slightly underdamped convergence characteristic. SHIFT_KH
> @@ -135,6 +137,8 @@ struct timex {
> #define ADJ_ESTERROR 0x0008 /* estimated time error */
> #define ADJ_STATUS 0x0010 /* clock status */
> #define ADJ_TIMECONST 0x0020 /* pll time constant */
> +#define ADJ_MICRO 0x1000 /* select microsecond resolution */
> +#define ADJ_NANO 0x2000 /* select nanosecond resolution */
> #define ADJ_TICK 0x4000 /* tick value */
> #define ADJ_OFFSET_SINGLESHOT 0x8001 /* old-fashioned adjtime */
> #define ADJ_OFFSET_SS_READ 0xa001 /* read-only adjtime */
> @@ -146,8 +150,6 @@ struct timex {
> #define MOD_ESTERROR ADJ_ESTERROR
> #define MOD_STATUS ADJ_STATUS
> #define MOD_TIMECONST ADJ_TIMECONST
> -#define MOD_CLKB ADJ_TICK
> -#define MOD_CLKA ADJ_OFFSET_SINGLESHOT /* 0x8000 in original */
>
>
> /*
> @@ -169,9 +171,13 @@ struct timex {
> #define STA_PPSERROR 0x0800 /* PPS signal calibration error (ro) */
>
> #define STA_CLOCKERR 0x1000 /* clock hardware fault (ro) */
> +#define STA_NANO 0x2000 /* resolution (0 = us, 1 = ns) (ro) */
> +#define STA_MODE 0x4000 /* mode (0 = PLL, 1 = FLL) (ro) */
> +#define STA_CLK 0x8000 /* clock source (0 = A, 1 = B) (ro) */
>
> +/* read-only bits */
> #define STA_RONLY (STA_PPSSIGNAL | STA_PPSJITTER | STA_PPSWANDER | \
> - STA_PPSERROR | STA_CLOCKERR) /* read-only bits */
> + STA_PPSERROR | STA_CLOCKERR | STA_NANO | STA_MODE | STA_CLK)
>
> /*
> * Clock states (time_state)
> Index: linux-2.6/kernel/time/ntp.c
> ===================================================================
> --- linux-2.6.orig/kernel/time/ntp.c 2008-03-13 10:42:20.000000000 +0100
> +++ linux-2.6/kernel/time/ntp.c 2008-03-13 10:47:49.000000000 +0100
> @@ -65,7 +65,9 @@ static void ntp_update_offset(long offse
> if (!(time_status & STA_PLL))
> return;
>
> - time_offset = offset * NSEC_PER_USEC;
> + time_offset = offset;
> + if (!(time_status & STA_NANO))
> + time_offset *= NSEC_PER_USEC;
>
> /*
> * Scale the phase adjustment and
> @@ -86,8 +88,11 @@ static void ntp_update_offset(long offse
> freq_adj = time_offset * mtemp;
> freq_adj = shift_right(freq_adj, time_constant * 2 +
> (SHIFT_PLL + 2) * 2 - SHIFT_NSEC);
> - if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > MAXSEC))
> + time_status &= ~STA_MODE;
> + if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > MAXSEC)) {
> freq_adj += div_s64(time_offset << (SHIFT_NSEC - SHIFT_FLL), mtemp);
> + time_status |= STA_MODE;
> + }
> freq_adj += time_freq;
> freq_adj = min(freq_adj, (s64)MAXFREQ_NSEC);
> time_freq = max(freq_adj, (s64)-MAXFREQ_NSEC);
> @@ -272,6 +277,7 @@ static inline void notify_cmos_timer(voi
> */
> int do_adjtimex(struct timex *txc)
> {
> + struct timespec ts;
> long save_adjust;
> int result;
>
> @@ -282,17 +288,11 @@ int do_adjtimex(struct timex *txc)
> /* Now we validate the data before disabling interrupts */
>
> if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT) {
> - /* singleshot must not be used with any other mode bits */
> - if (txc->modes != ADJ_OFFSET_SINGLESHOT &&
> - txc->modes != ADJ_OFFSET_SS_READ)
> + /* singleshot must not be used with any other mode bits */
> + if (txc->modes & ~ADJ_OFFSET_SS_READ)
> return -EINVAL;
This could probably go in the cleanup patch, no?
> }
>
> - if (txc->modes != ADJ_OFFSET_SINGLESHOT && (txc->modes & ADJ_OFFSET))
> - /* adjustment Offset limited to +- .512 seconds */
> - if (txc->offset <= - MAXPHASE || txc->offset >= MAXPHASE )
> - return -EINVAL;
> -
> /* if the quartz is off by more than 10% something is VERY wrong ! */
> if (txc->modes & ADJ_TICK)
> if (txc->tick < 900000/USER_HZ ||
> @@ -300,51 +300,46 @@ int do_adjtimex(struct timex *txc)
> return -EINVAL;
>
> write_seqlock_irq(&xtime_lock);
> - result = time_state; /* mostly `TIME_OK' */
>
> /* Save for later - semantics of adjtime is to return old value */
> save_adjust = time_adjust;
>
> -#if 0 /* STA_CLOCKERR is never set yet */
> - time_status &= ~STA_CLOCKERR; /* reset STA_CLOCKERR */
> -#endif
This as well is just cleanup.
> /* If there are input parameters, then process them */
> if (txc->modes) {
> - if (txc->modes & ADJ_STATUS) /* only set allowed bits */
> - time_status = (txc->status & ~STA_RONLY) |
> - (time_status & STA_RONLY);
> + 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;
> + }
More cleanup.
> + if (txc->modes & ADJ_NANO)
> + time_status |= STA_NANO;
> + if (txc->modes & ADJ_MICRO)
> + time_status &= ~STA_NANO;
>
> if (txc->modes & ADJ_FREQUENCY) {
> - if (txc->freq > MAXFREQ || txc->freq < -MAXFREQ) {
> - result = -EINVAL;
> - goto leave;
> - }
> - time_freq = ((s64)txc->freq * NSEC_PER_USEC)
> + time_freq = min(txc->freq, MAXFREQ);
> + time_freq = min(time_freq, -MAXFREQ);
> + time_freq = ((s64)time_freq * NSEC_PER_USEC)
> >> (SHIFT_USEC - SHIFT_NSEC);
> }
>
> - if (txc->modes & ADJ_MAXERROR) {
> - if (txc->maxerror < 0 || txc->maxerror >= NTP_PHASE_LIMIT) {
> - result = -EINVAL;
> - goto leave;
> - }
> + if (txc->modes & ADJ_MAXERROR)
> time_maxerror = txc->maxerror;
> - }
> -
> - if (txc->modes & ADJ_ESTERROR) {
> - if (txc->esterror < 0 || txc->esterror >= NTP_PHASE_LIMIT) {
> - result = -EINVAL;
> - goto leave;
> - }
> + if (txc->modes & ADJ_ESTERROR)
> time_esterror = txc->esterror;
> - }
>
> if (txc->modes & ADJ_TIMECONST) {
> - if (txc->constant < 0) { /* NTP v4 uses values > 6 */
> - result = -EINVAL;
> - goto leave;
> - }
> - time_constant = min(txc->constant + 4, (long)MAXTC);
> + 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_OFFSET) {
> @@ -360,16 +355,20 @@ int do_adjtimex(struct timex *txc)
> if (txc->modes & (ADJ_TICK|ADJ_FREQUENCY|ADJ_OFFSET))
> ntp_update_frequency();
> }
> -leave:
> +
> + result = time_state; /* mostly `TIME_OK' */
> if (time_status & (STA_UNSYNC|STA_CLOCKERR))
> result = TIME_ERROR;
>
> if ((txc->modes == ADJ_OFFSET_SINGLESHOT) ||
> (txc->modes == ADJ_OFFSET_SS_READ))
> txc->offset = save_adjust;
> - else
> + else {
> txc->offset = ((long)shift_right(time_offset, SHIFT_UPDATE)) *
> - NTP_INTERVAL_FREQ / 1000;
> + NTP_INTERVAL_FREQ;
> + if (!(time_status & STA_NANO))
> + txc->offset /= NSEC_PER_USEC;
> + }
> txc->freq = (time_freq / NSEC_PER_USEC) <<
> (SHIFT_USEC - SHIFT_NSEC);
> txc->maxerror = time_maxerror;
> @@ -391,7 +390,11 @@ leave:
> txc->stbcnt = 0;
> write_sequnlock_irq(&xtime_lock);
>
> - do_gettimeofday(&txc->time);
> + getnstimeofday(&ts);
> + txc->time.tv_sec = ts.tv_sec;
> + txc->time.tv_usec = ts.tv_nsec;
> + if (!(time_status & STA_NANO))
> + txc->time.tv_usec /= NSEC_PER_USEC;
--
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