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powerpc: Fix time setting bug on 32-bit

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This fixes a bug where settimeofday would set the wrong parameters
in do_gtod, resulting in gettimeofday returning a value about 4
hours after the correct time.  The bug was that we divided a
negative 64-bit value with do_div, which treated it as unsigned
and gave us a result that was approximately 1.8e10 too large
(since the divisor was 1e9).

Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Paul Mackerras 2005-10-30 22:55:52 +11:00
parent eb66ce6333
commit 5f6b5b973a
1 changed files with 8 additions and 6 deletions
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14
arch/powerpc/kernel/time.c
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@ -518,7 +518,7 @@ int do_settimeofday(struct timespec *tv)
long wtm_nsec, new_nsec = tv->tv_nsec;
unsigned long flags;
long int tb_delta;
u64 new_xsec;
u64 new_xsec, tb_delta_xs;
if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
return -EINVAL;
@ -541,8 +541,7 @@ int do_settimeofday(struct timespec *tv)
#endif
tb_delta = tb_ticks_since(tb_last_stamp);
tb_delta += (jiffies - wall_jiffies) * tb_ticks_per_jiffy;
new_nsec -= 1000 * mulhwu(tb_to_us, tb_delta);
tb_delta_xs = mulhdu(tb_delta, do_gtod.varp->tb_to_xs);
wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - new_sec);
wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - new_nsec);
@ -557,9 +556,12 @@ int do_settimeofday(struct timespec *tv)
ntp_clear();
new_xsec = (u64)new_nsec * XSEC_PER_SEC;
do_div(new_xsec, NSEC_PER_SEC);
new_xsec += (u64)new_sec * XSEC_PER_SEC;
new_xsec = 0;
if (new_nsec != 0) {
new_xsec = (u64)new_nsec * XSEC_PER_SEC;
do_div(new_xsec, NSEC_PER_SEC);
}
new_xsec += (u64)new_sec * XSEC_PER_SEC - tb_delta_xs;
update_gtod(tb_last_jiffy, new_xsec, do_gtod.varp->tb_to_xs);
#ifdef CONFIG_PPC64