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authorLin Ming <ming.m.lin@intel.com>2009-11-17 13:49:50 +0800
committerThomas Gleixner <tglx@linutronix.de>2009-11-17 11:52:34 +0100
commit0696b711e4be45fa104c12329f617beb29c03f78 (patch)
tree96292fdc4ab443d6218077d363548532df6cbd8b /arch/powerpc/kernel/time.c
parenta9366e61b03f55a6e009e687ad10e706714c9907 (diff)
downloadop-kernel-dev-0696b711e4be45fa104c12329f617beb29c03f78.zip
op-kernel-dev-0696b711e4be45fa104c12329f617beb29c03f78.tar.gz
timekeeping: Fix clock_gettime vsyscall time warp
Since commit 0a544198 "timekeeping: Move NTP adjusted clock multiplier to struct timekeeper" the clock multiplier of vsyscall is updated with the unmodified clock multiplier of the clock source and not with the NTP adjusted multiplier of the timekeeper. This causes user space observerable time warps: new CLOCK-warp maximum: 120 nsecs, 00000025c337c537 -> 00000025c337c4bf Add a new argument "mult" to update_vsyscall() and hand in the timekeeping internal NTP adjusted multiplier. Signed-off-by: Lin Ming <ming.m.lin@intel.com> Cc: "Zhang Yanmin" <yanmin_zhang@linux.intel.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Tony Luck <tony.luck@intel.com> LKML-Reference: <1258436990.17765.83.camel@minggr.sh.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/powerpc/kernel/time.c')
-rw-r--r--arch/powerpc/kernel/time.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index a136a11c490..3971331 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -828,7 +828,8 @@ static cycle_t timebase_read(struct clocksource *cs)
return (cycle_t)get_tb();
}
-void update_vsyscall(struct timespec *wall_time, struct clocksource *clock)
+void update_vsyscall(struct timespec *wall_time, struct clocksource *clock,
+ u32 mult)
{
u64 t2x, stamp_xsec;
@@ -841,7 +842,7 @@ void update_vsyscall(struct timespec *wall_time, struct clocksource *clock)
/* XXX this assumes clock->shift == 22 */
/* 4611686018 ~= 2^(20+64-22) / 1e9 */
- t2x = (u64) clock->mult * 4611686018ULL;
+ t2x = (u64) mult * 4611686018ULL;
stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC;
do_div(stamp_xsec, 1000000000);
stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC;
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