2006-10-01 08:28:22 +02:00
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/*
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* linux/kernel/time/ntp.c
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*
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* NTP state machine interfaces and logic.
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*
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* This code was mainly moved from kernel/timer.c and kernel/time.c
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* Please see those files for relevant copyright info and historical
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* changelogs.
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*/
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#include <linux/mm.h>
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#include <linux/time.h>
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2007-07-21 13:37:37 +02:00
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#include <linux/timer.h>
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2006-10-01 08:28:22 +02:00
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#include <linux/timex.h>
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Detach sched.h from mm.h
First thing mm.h does is including sched.h solely for can_do_mlock() inline
function which has "current" dereference inside. By dealing with can_do_mlock()
mm.h can be detached from sched.h which is good. See below, why.
This patch
a) removes unconditional inclusion of sched.h from mm.h
b) makes can_do_mlock() normal function in mm/mlock.c
c) exports can_do_mlock() to not break compilation
d) adds sched.h inclusions back to files that were getting it indirectly.
e) adds less bloated headers to some files (asm/signal.h, jiffies.h) that were
getting them indirectly
Net result is:
a) mm.h users would get less code to open, read, preprocess, parse, ... if
they don't need sched.h
b) sched.h stops being dependency for significant number of files:
on x86_64 allmodconfig touching sched.h results in recompile of 4083 files,
after patch it's only 3744 (-8.3%).
Cross-compile tested on
all arm defconfigs, all mips defconfigs, all powerpc defconfigs,
alpha alpha-up
arm
i386 i386-up i386-defconfig i386-allnoconfig
ia64 ia64-up
m68k
mips
parisc parisc-up
powerpc powerpc-up
s390 s390-up
sparc sparc-up
sparc64 sparc64-up
um-x86_64
x86_64 x86_64-up x86_64-defconfig x86_64-allnoconfig
as well as my two usual configs.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-20 23:22:52 +02:00
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#include <linux/jiffies.h>
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#include <linux/hrtimer.h>
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2007-07-16 08:40:39 +02:00
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#include <linux/capability.h>
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2008-05-01 13:34:26 +02:00
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#include <linux/math64.h>
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2006-10-01 08:28:22 +02:00
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#include <asm/timex.h>
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2006-10-01 08:28:22 +02:00
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/*
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* Timekeeping variables
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*/
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unsigned long tick_usec = TICK_USEC; /* USER_HZ period (usec) */
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unsigned long tick_nsec; /* ACTHZ period (nsec) */
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static u64 tick_length, tick_length_base;
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2006-10-01 08:28:25 +02:00
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#define MAX_TICKADJ 500 /* microsecs */
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#define MAX_TICKADJ_SCALED (((u64)(MAX_TICKADJ * NSEC_PER_USEC) << \
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2007-02-16 10:27:26 +01:00
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TICK_LENGTH_SHIFT) / NTP_INTERVAL_FREQ)
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2006-10-01 08:28:22 +02:00
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/*
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* phase-lock loop variables
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*/
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/* TIME_ERROR prevents overwriting the CMOS clock */
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2006-10-01 08:28:29 +02:00
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static int time_state = TIME_OK; /* clock synchronization status */
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2006-10-01 08:28:22 +02:00
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int time_status = STA_UNSYNC; /* clock status bits */
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2008-05-01 13:34:32 +02:00
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static s64 time_offset; /* time adjustment (ns) */
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2006-10-01 08:28:29 +02:00
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static long time_constant = 2; /* pll time constant */
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2006-10-01 08:28:22 +02:00
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long time_maxerror = NTP_PHASE_LIMIT; /* maximum error (us) */
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long time_esterror = NTP_PHASE_LIMIT; /* estimated error (us) */
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2008-05-01 13:34:34 +02:00
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static s64 time_freq; /* frequency offset (scaled ns/s)*/
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2006-10-01 08:28:29 +02:00
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static long time_reftime; /* time at last adjustment (s) */
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2006-10-01 08:28:22 +02:00
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long time_adjust;
|
time: remove obsolete CLOCK_TICK_ADJUST
The first version of the ntp_interval/tick_length inconsistent usage patch was
recently merged as bbe4d18ac2e058c56adb0cd71f49d9ed3216a405
http://git.kernel.org/gitweb.cgi?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=bbe4d18ac2e058c56adb0cd71f49d9ed3216a405
While the fix did greatly improve the situation, it was correctly pointed out
by Roman that it does have a small bug: If the users change clocksources after
the system has been running and NTP has made corrections, the correctoins made
against the old clocksource will be applied against the new clocksource,
causing error.
The second attempt, which corrects the issue in the NTP_INTERVAL_LENGTH
definition has also made it up-stream as commit
e13a2e61dd5152f5499d2003470acf9c838eab84
http://git.kernel.org/gitweb.cgi?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e13a2e61dd5152f5499d2003470acf9c838eab84
Roman has correctly pointed out that CLOCK_TICK_ADJUST is calculated
based on the PIT's frequency, and isn't really relevant to non-PIT
driven clocksources (that is, clocksources other then jiffies and pit).
This patch reverts both of those changes, and simply removes
CLOCK_TICK_ADJUST.
This does remove the granularity error correction for users of PIT and Jiffies
clocksource users, but the granularity error but for the majority of users, it
should be within the 500ppm range NTP can accommodate for.
For systems that have granularity errors greater then 500ppm, the
"ntp_tick_adj=" boot option can be used to compensate.
[johnstul@us.ibm.com: provided changelog]
[mattilinnanvuori@yahoo.com: maek ntp_tick_adj static]
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Acked-by: john stultz <johnstul@us.ibm.com>
Signed-off-by: Matti Linnanvuori <mattilinnanvuori@yahoo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: mingo@elte.hu
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-03-05 00:14:26 +01:00
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static long ntp_tick_adj;
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2006-10-01 08:28:22 +02:00
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2006-10-01 08:28:29 +02:00
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static void ntp_update_frequency(void)
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{
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2007-02-16 10:27:26 +01:00
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u64 second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ)
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<< TICK_LENGTH_SHIFT;
|
time: remove obsolete CLOCK_TICK_ADJUST
The first version of the ntp_interval/tick_length inconsistent usage patch was
recently merged as bbe4d18ac2e058c56adb0cd71f49d9ed3216a405
http://git.kernel.org/gitweb.cgi?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=bbe4d18ac2e058c56adb0cd71f49d9ed3216a405
While the fix did greatly improve the situation, it was correctly pointed out
by Roman that it does have a small bug: If the users change clocksources after
the system has been running and NTP has made corrections, the correctoins made
against the old clocksource will be applied against the new clocksource,
causing error.
The second attempt, which corrects the issue in the NTP_INTERVAL_LENGTH
definition has also made it up-stream as commit
e13a2e61dd5152f5499d2003470acf9c838eab84
http://git.kernel.org/gitweb.cgi?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e13a2e61dd5152f5499d2003470acf9c838eab84
Roman has correctly pointed out that CLOCK_TICK_ADJUST is calculated
based on the PIT's frequency, and isn't really relevant to non-PIT
driven clocksources (that is, clocksources other then jiffies and pit).
This patch reverts both of those changes, and simply removes
CLOCK_TICK_ADJUST.
This does remove the granularity error correction for users of PIT and Jiffies
clocksource users, but the granularity error but for the majority of users, it
should be within the 500ppm range NTP can accommodate for.
For systems that have granularity errors greater then 500ppm, the
"ntp_tick_adj=" boot option can be used to compensate.
[johnstul@us.ibm.com: provided changelog]
[mattilinnanvuori@yahoo.com: maek ntp_tick_adj static]
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Acked-by: john stultz <johnstul@us.ibm.com>
Signed-off-by: Matti Linnanvuori <mattilinnanvuori@yahoo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: mingo@elte.hu
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-03-05 00:14:26 +01:00
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second_length += (s64)ntp_tick_adj << TICK_LENGTH_SHIFT;
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2008-05-01 13:34:34 +02:00
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second_length += time_freq;
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2006-10-01 08:28:29 +02:00
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2007-02-16 10:27:26 +01:00
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tick_length_base = second_length;
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2006-10-01 08:28:29 +02:00
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2008-05-01 13:34:26 +02:00
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tick_nsec = div_u64(second_length, HZ) >> TICK_LENGTH_SHIFT;
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tick_length_base = div_u64(tick_length_base, NTP_INTERVAL_FREQ);
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2006-10-01 08:28:29 +02:00
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}
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2008-05-01 13:34:32 +02:00
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static void ntp_update_offset(long offset)
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{
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long mtemp;
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s64 freq_adj;
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if (!(time_status & STA_PLL))
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return;
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2008-05-01 13:34:33 +02:00
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time_offset = offset;
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if (!(time_status & STA_NANO))
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time_offset *= NSEC_PER_USEC;
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2008-05-01 13:34:32 +02:00
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/*
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* Scale the phase adjustment and
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* clamp to the operating range.
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*/
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time_offset = min(time_offset, (s64)MAXPHASE * NSEC_PER_USEC);
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time_offset = max(time_offset, (s64)-MAXPHASE * NSEC_PER_USEC);
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/*
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* Select how the frequency is to be controlled
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* and in which mode (PLL or FLL).
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*/
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if (time_status & STA_FREQHOLD || time_reftime == 0)
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time_reftime = xtime.tv_sec;
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mtemp = xtime.tv_sec - time_reftime;
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time_reftime = xtime.tv_sec;
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freq_adj = time_offset * mtemp;
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2008-05-01 13:34:34 +02:00
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freq_adj <<= TICK_LENGTH_SHIFT - 2 * (SHIFT_PLL + 2 + time_constant);
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2008-05-01 13:34:33 +02:00
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time_status &= ~STA_MODE;
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if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > MAXSEC)) {
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2008-05-01 13:34:34 +02:00
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freq_adj += div_s64(time_offset << (TICK_LENGTH_SHIFT - SHIFT_FLL),
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mtemp);
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2008-05-01 13:34:33 +02:00
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time_status |= STA_MODE;
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}
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2008-05-01 13:34:32 +02:00
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freq_adj += time_freq;
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2008-05-01 13:34:34 +02:00
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freq_adj = min(freq_adj, MAXFREQ_SCALED);
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time_freq = max(freq_adj, -MAXFREQ_SCALED);
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2008-05-01 13:34:32 +02:00
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time_offset = div_s64(time_offset, NTP_INTERVAL_FREQ);
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time_offset <<= SHIFT_UPDATE;
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}
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2006-10-01 08:28:22 +02:00
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/**
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* ntp_clear - Clears the NTP state variables
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*
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* Must be called while holding a write on the xtime_lock
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*/
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void ntp_clear(void)
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{
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time_adjust = 0; /* stop active adjtime() */
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time_status |= STA_UNSYNC;
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time_maxerror = NTP_PHASE_LIMIT;
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time_esterror = NTP_PHASE_LIMIT;
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ntp_update_frequency();
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tick_length = tick_length_base;
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2006-10-01 08:28:25 +02:00
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time_offset = 0;
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2006-10-01 08:28:22 +02:00
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}
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2006-10-01 08:28:22 +02:00
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/*
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* this routine handles the overflow of the microsecond field
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*
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* The tricky bits of code to handle the accurate clock support
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* were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame.
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* They were originally developed for SUN and DEC kernels.
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* All the kudos should go to Dave for this stuff.
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*/
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void second_overflow(void)
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{
|
2006-10-01 08:28:25 +02:00
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long time_adj;
|
2006-10-01 08:28:22 +02:00
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/* Bump the maxerror field */
|
2008-05-01 13:34:34 +02:00
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time_maxerror += MAXFREQ / NSEC_PER_USEC;
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2006-10-01 08:28:22 +02:00
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if (time_maxerror > NTP_PHASE_LIMIT) {
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time_maxerror = NTP_PHASE_LIMIT;
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time_status |= STA_UNSYNC;
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}
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/*
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* Leap second processing. If in leap-insert state at the end of the
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* day, the system clock is set back one second; if in leap-delete
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* state, the system clock is set ahead one second. The microtime()
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* routine or external clock driver will insure that reported time is
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* always monotonic. The ugly divides should be replaced.
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*/
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switch (time_state) {
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case TIME_OK:
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if (time_status & STA_INS)
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time_state = TIME_INS;
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else if (time_status & STA_DEL)
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time_state = TIME_DEL;
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break;
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case TIME_INS:
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if (xtime.tv_sec % 86400 == 0) {
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xtime.tv_sec--;
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wall_to_monotonic.tv_sec++;
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time_state = TIME_OOP;
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printk(KERN_NOTICE "Clock: inserting leap second "
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"23:59:60 UTC\n");
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}
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break;
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case TIME_DEL:
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if ((xtime.tv_sec + 1) % 86400 == 0) {
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xtime.tv_sec++;
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wall_to_monotonic.tv_sec--;
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time_state = TIME_WAIT;
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printk(KERN_NOTICE "Clock: deleting leap second "
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"23:59:59 UTC\n");
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}
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break;
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case TIME_OOP:
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time_state = TIME_WAIT;
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break;
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case TIME_WAIT:
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if (!(time_status & (STA_INS | STA_DEL)))
|
2008-05-01 13:34:32 +02:00
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time_state = TIME_OK;
|
2006-10-01 08:28:22 +02:00
|
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}
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/*
|
2006-10-01 08:28:28 +02:00
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* Compute the phase adjustment for the next second. The offset is
|
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* reduced by a fixed factor times the time constant.
|
2006-10-01 08:28:22 +02:00
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*/
|
2006-10-01 08:28:22 +02:00
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tick_length = tick_length_base;
|
2006-10-01 08:28:28 +02:00
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time_adj = shift_right(time_offset, SHIFT_PLL + time_constant);
|
2006-10-01 08:28:25 +02:00
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time_offset -= time_adj;
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tick_length += (s64)time_adj << (TICK_LENGTH_SHIFT - SHIFT_UPDATE);
|
2006-10-01 08:28:22 +02:00
|
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|
2006-10-01 08:28:25 +02:00
|
|
|
if (unlikely(time_adjust)) {
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|
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if (time_adjust > MAX_TICKADJ) {
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time_adjust -= MAX_TICKADJ;
|
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|
|
tick_length += MAX_TICKADJ_SCALED;
|
|
|
|
} else if (time_adjust < -MAX_TICKADJ) {
|
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|
|
time_adjust += MAX_TICKADJ;
|
|
|
|
tick_length -= MAX_TICKADJ_SCALED;
|
|
|
|
} else {
|
|
|
|
tick_length += (s64)(time_adjust * NSEC_PER_USEC /
|
2007-02-16 10:27:26 +01:00
|
|
|
NTP_INTERVAL_FREQ) << TICK_LENGTH_SHIFT;
|
2006-10-28 19:38:56 +02:00
|
|
|
time_adjust = 0;
|
2006-10-01 08:28:25 +02:00
|
|
|
}
|
2006-10-01 08:28:22 +02:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Return how long ticks are at the moment, that is, how much time
|
|
|
|
* update_wall_time_one_tick will add to xtime next time we call it
|
|
|
|
* (assuming no calls to do_adjtimex in the meantime).
|
|
|
|
* The return value is in fixed-point nanoseconds shifted by the
|
|
|
|
* specified number of bits to the right of the binary point.
|
|
|
|
* This function has no side-effects.
|
|
|
|
*/
|
|
|
|
u64 current_tick_length(void)
|
|
|
|
{
|
2006-10-01 08:28:25 +02:00
|
|
|
return tick_length;
|
2006-10-01 08:28:22 +02:00
|
|
|
}
|
|
|
|
|
2007-07-21 13:37:37 +02:00
|
|
|
#ifdef CONFIG_GENERIC_CMOS_UPDATE
|
2006-10-01 08:28:22 +02:00
|
|
|
|
2007-07-21 13:37:37 +02:00
|
|
|
/* Disable the cmos update - used by virtualization and embedded */
|
|
|
|
int no_sync_cmos_clock __read_mostly;
|
|
|
|
|
|
|
|
static void sync_cmos_clock(unsigned long dummy);
|
|
|
|
|
|
|
|
static DEFINE_TIMER(sync_cmos_timer, sync_cmos_clock, 0, 0);
|
|
|
|
|
|
|
|
static void sync_cmos_clock(unsigned long dummy)
|
|
|
|
{
|
|
|
|
struct timespec now, next;
|
|
|
|
int fail = 1;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* If we have an externally synchronized Linux clock, then update
|
|
|
|
* CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
|
|
|
|
* called as close as possible to 500 ms before the new second starts.
|
|
|
|
* This code is run on a timer. If the clock is set, that timer
|
|
|
|
* may not expire at the correct time. Thus, we adjust...
|
|
|
|
*/
|
|
|
|
if (!ntp_synced())
|
|
|
|
/*
|
|
|
|
* Not synced, exit, do not restart a timer (if one is
|
|
|
|
* running, let it run out).
|
|
|
|
*/
|
|
|
|
return;
|
|
|
|
|
|
|
|
getnstimeofday(&now);
|
ntp: fix typo that makes sync_cmos_clock erratic
Fix a typo in ntp.c that has caused updating of the persistent (RTC)
clock when synced to NTP to behave erratically.
When debugging a freeze that arises on my AMD64 machines when I
run the ntpd service, I added a number of printk's to monitor the
sync_cmos_clock procedure. I discovered that it was not syncing to
cmos RTC every 11 minutes as documented, but instead would keep trying
every second for hours at a time. The reason turned out to be a typo
in sync_cmos_clock, where it attempts to ensure that
update_persistent_clock is called very close to 500 msec. after a 1
second boundary (required by the PC RTC's spec). That typo referred to
"xtime" in one spot, rather than "now", which is derived from "xtime"
but not equal to it. This makes the test erratic, creating a
"coin-flip" that decides when update_persistent_clock is called - when
it is called, which is rarely, it may be at any time during the one
second period, rather than close to 500 msec, so the value written is
needlessly incorrect, too.
Signed-off-by: David P. Reed
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2007-11-14 23:49:21 +01:00
|
|
|
if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2)
|
2007-07-21 13:37:37 +02:00
|
|
|
fail = update_persistent_clock(now);
|
|
|
|
|
|
|
|
next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec;
|
|
|
|
if (next.tv_nsec <= 0)
|
|
|
|
next.tv_nsec += NSEC_PER_SEC;
|
|
|
|
|
|
|
|
if (!fail)
|
|
|
|
next.tv_sec = 659;
|
|
|
|
else
|
|
|
|
next.tv_sec = 0;
|
|
|
|
|
|
|
|
if (next.tv_nsec >= NSEC_PER_SEC) {
|
|
|
|
next.tv_sec++;
|
|
|
|
next.tv_nsec -= NSEC_PER_SEC;
|
|
|
|
}
|
|
|
|
mod_timer(&sync_cmos_timer, jiffies + timespec_to_jiffies(&next));
|
|
|
|
}
|
|
|
|
|
|
|
|
static void notify_cmos_timer(void)
|
2006-10-01 08:28:22 +02:00
|
|
|
{
|
2007-09-12 00:24:03 +02:00
|
|
|
if (!no_sync_cmos_clock)
|
2007-07-21 13:37:37 +02:00
|
|
|
mod_timer(&sync_cmos_timer, jiffies + 1);
|
2006-10-01 08:28:22 +02:00
|
|
|
}
|
|
|
|
|
2007-07-21 13:37:37 +02:00
|
|
|
#else
|
|
|
|
static inline void notify_cmos_timer(void) { }
|
|
|
|
#endif
|
|
|
|
|
2006-10-01 08:28:22 +02:00
|
|
|
/* adjtimex mainly allows reading (and writing, if superuser) of
|
|
|
|
* kernel time-keeping variables. used by xntpd.
|
|
|
|
*/
|
|
|
|
int do_adjtimex(struct timex *txc)
|
|
|
|
{
|
2008-05-01 13:34:33 +02:00
|
|
|
struct timespec ts;
|
2008-05-01 13:34:32 +02:00
|
|
|
long save_adjust;
|
2006-10-01 08:28:22 +02:00
|
|
|
int result;
|
|
|
|
|
|
|
|
/* In order to modify anything, you gotta be super-user! */
|
|
|
|
if (txc->modes && !capable(CAP_SYS_TIME))
|
|
|
|
return -EPERM;
|
|
|
|
|
|
|
|
/* Now we validate the data before disabling interrupts */
|
|
|
|
|
2007-11-26 20:42:19 +01:00
|
|
|
if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT) {
|
2008-05-01 13:34:33 +02:00
|
|
|
/* singleshot must not be used with any other mode bits */
|
|
|
|
if (txc->modes & ~ADJ_OFFSET_SS_READ)
|
2006-10-01 08:28:22 +02:00
|
|
|
return -EINVAL;
|
2007-11-26 20:42:19 +01:00
|
|
|
}
|
2006-10-01 08:28:22 +02:00
|
|
|
|
|
|
|
/* if the quartz is off by more than 10% something is VERY wrong ! */
|
|
|
|
if (txc->modes & ADJ_TICK)
|
|
|
|
if (txc->tick < 900000/USER_HZ ||
|
|
|
|
txc->tick > 1100000/USER_HZ)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
write_seqlock_irq(&xtime_lock);
|
|
|
|
|
|
|
|
/* Save for later - semantics of adjtime is to return old value */
|
2006-10-01 08:28:25 +02:00
|
|
|
save_adjust = time_adjust;
|
2006-10-01 08:28:22 +02:00
|
|
|
|
|
|
|
/* If there are input parameters, then process them */
|
2008-05-01 13:34:32 +02:00
|
|
|
if (txc->modes) {
|
2008-05-01 13:34:33 +02:00
|
|
|
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;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (txc->modes & ADJ_NANO)
|
|
|
|
time_status |= STA_NANO;
|
|
|
|
if (txc->modes & ADJ_MICRO)
|
|
|
|
time_status &= ~STA_NANO;
|
2008-05-01 13:34:32 +02:00
|
|
|
|
|
|
|
if (txc->modes & ADJ_FREQUENCY) {
|
2008-05-01 13:34:34 +02:00
|
|
|
time_freq = (s64)txc->freq * PPM_SCALE;
|
|
|
|
time_freq = min(time_freq, MAXFREQ_SCALED);
|
|
|
|
time_freq = max(time_freq, -MAXFREQ_SCALED);
|
2006-10-01 08:28:22 +02:00
|
|
|
}
|
2008-05-01 13:34:32 +02:00
|
|
|
|
2008-05-01 13:34:33 +02:00
|
|
|
if (txc->modes & ADJ_MAXERROR)
|
2008-05-01 13:34:32 +02:00
|
|
|
time_maxerror = txc->maxerror;
|
2008-05-01 13:34:33 +02:00
|
|
|
if (txc->modes & ADJ_ESTERROR)
|
2008-05-01 13:34:32 +02:00
|
|
|
time_esterror = txc->esterror;
|
2006-10-01 08:28:22 +02:00
|
|
|
|
2008-05-01 13:34:32 +02:00
|
|
|
if (txc->modes & ADJ_TIMECONST) {
|
2008-05-01 13:34:33 +02:00
|
|
|
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);
|
2006-10-01 08:28:22 +02:00
|
|
|
}
|
|
|
|
|
2008-05-01 13:34:32 +02:00
|
|
|
if (txc->modes & ADJ_OFFSET) {
|
|
|
|
if (txc->modes == ADJ_OFFSET_SINGLESHOT)
|
|
|
|
/* adjtime() is independent from ntp_adjtime() */
|
|
|
|
time_adjust = txc->offset;
|
|
|
|
else
|
|
|
|
ntp_update_offset(txc->offset);
|
2006-10-01 08:28:22 +02:00
|
|
|
}
|
2008-05-01 13:34:32 +02:00
|
|
|
if (txc->modes & ADJ_TICK)
|
|
|
|
tick_usec = txc->tick;
|
|
|
|
|
|
|
|
if (txc->modes & (ADJ_TICK|ADJ_FREQUENCY|ADJ_OFFSET))
|
|
|
|
ntp_update_frequency();
|
|
|
|
}
|
2008-05-01 13:34:33 +02:00
|
|
|
|
|
|
|
result = time_state; /* mostly `TIME_OK' */
|
2008-05-01 13:34:32 +02:00
|
|
|
if (time_status & (STA_UNSYNC|STA_CLOCKERR))
|
2006-10-01 08:28:22 +02:00
|
|
|
result = TIME_ERROR;
|
|
|
|
|
2007-11-26 20:42:19 +01:00
|
|
|
if ((txc->modes == ADJ_OFFSET_SINGLESHOT) ||
|
2008-05-01 13:34:32 +02:00
|
|
|
(txc->modes == ADJ_OFFSET_SS_READ))
|
2007-03-27 07:32:26 +02:00
|
|
|
txc->offset = save_adjust;
|
2008-05-01 13:34:33 +02:00
|
|
|
else {
|
2007-03-27 07:32:26 +02:00
|
|
|
txc->offset = ((long)shift_right(time_offset, SHIFT_UPDATE)) *
|
2008-05-01 13:34:33 +02:00
|
|
|
NTP_INTERVAL_FREQ;
|
|
|
|
if (!(time_status & STA_NANO))
|
|
|
|
txc->offset /= NSEC_PER_USEC;
|
|
|
|
}
|
2008-05-01 13:34:34 +02:00
|
|
|
txc->freq = shift_right((s32)(time_freq >> PPM_SCALE_INV_SHIFT) *
|
|
|
|
(s64)PPM_SCALE_INV,
|
|
|
|
TICK_LENGTH_SHIFT);
|
2006-10-01 08:28:22 +02:00
|
|
|
txc->maxerror = time_maxerror;
|
|
|
|
txc->esterror = time_esterror;
|
|
|
|
txc->status = time_status;
|
|
|
|
txc->constant = time_constant;
|
2006-10-01 08:28:29 +02:00
|
|
|
txc->precision = 1;
|
2008-05-01 13:34:34 +02:00
|
|
|
txc->tolerance = MAXFREQ_SCALED / PPM_SCALE;
|
2006-10-01 08:28:22 +02:00
|
|
|
txc->tick = tick_usec;
|
|
|
|
|
|
|
|
/* PPS is not implemented, so these are zero */
|
|
|
|
txc->ppsfreq = 0;
|
|
|
|
txc->jitter = 0;
|
|
|
|
txc->shift = 0;
|
|
|
|
txc->stabil = 0;
|
|
|
|
txc->jitcnt = 0;
|
|
|
|
txc->calcnt = 0;
|
|
|
|
txc->errcnt = 0;
|
|
|
|
txc->stbcnt = 0;
|
|
|
|
write_sequnlock_irq(&xtime_lock);
|
2008-05-01 13:34:32 +02:00
|
|
|
|
2008-05-01 13:34:33 +02:00
|
|
|
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;
|
2008-05-01 13:34:32 +02:00
|
|
|
|
2007-07-21 13:37:37 +02:00
|
|
|
notify_cmos_timer();
|
2008-05-01 13:34:32 +02:00
|
|
|
|
|
|
|
return result;
|
2006-10-01 08:28:22 +02:00
|
|
|
}
|
time: remove obsolete CLOCK_TICK_ADJUST
The first version of the ntp_interval/tick_length inconsistent usage patch was
recently merged as bbe4d18ac2e058c56adb0cd71f49d9ed3216a405
http://git.kernel.org/gitweb.cgi?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=bbe4d18ac2e058c56adb0cd71f49d9ed3216a405
While the fix did greatly improve the situation, it was correctly pointed out
by Roman that it does have a small bug: If the users change clocksources after
the system has been running and NTP has made corrections, the correctoins made
against the old clocksource will be applied against the new clocksource,
causing error.
The second attempt, which corrects the issue in the NTP_INTERVAL_LENGTH
definition has also made it up-stream as commit
e13a2e61dd5152f5499d2003470acf9c838eab84
http://git.kernel.org/gitweb.cgi?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e13a2e61dd5152f5499d2003470acf9c838eab84
Roman has correctly pointed out that CLOCK_TICK_ADJUST is calculated
based on the PIT's frequency, and isn't really relevant to non-PIT
driven clocksources (that is, clocksources other then jiffies and pit).
This patch reverts both of those changes, and simply removes
CLOCK_TICK_ADJUST.
This does remove the granularity error correction for users of PIT and Jiffies
clocksource users, but the granularity error but for the majority of users, it
should be within the 500ppm range NTP can accommodate for.
For systems that have granularity errors greater then 500ppm, the
"ntp_tick_adj=" boot option can be used to compensate.
[johnstul@us.ibm.com: provided changelog]
[mattilinnanvuori@yahoo.com: maek ntp_tick_adj static]
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Acked-by: john stultz <johnstul@us.ibm.com>
Signed-off-by: Matti Linnanvuori <mattilinnanvuori@yahoo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: mingo@elte.hu
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-03-05 00:14:26 +01:00
|
|
|
|
|
|
|
static int __init ntp_tick_adj_setup(char *str)
|
|
|
|
{
|
|
|
|
ntp_tick_adj = simple_strtol(str, NULL, 0);
|
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
|
|
|
|
__setup("ntp_tick_adj=", ntp_tick_adj_setup);
|