From 0696b711e4be45fa104c12329f617beb29c03f78 Mon Sep 17 00:00:00 2001 From: Lin Ming Date: Tue, 17 Nov 2009 13:49:50 +0800 Subject: [PATCH] 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 Cc: "Zhang Yanmin" Cc: Martin Schwidefsky Cc: Benjamin Herrenschmidt Cc: Tony Luck LKML-Reference: <1258436990.17765.83.camel@minggr.sh.intel.com> Signed-off-by: Thomas Gleixner --- arch/ia64/kernel/time.c | 4 ++-- arch/powerpc/kernel/time.c | 5 +++-- arch/s390/kernel/time.c | 3 ++- arch/x86/kernel/vsyscall_64.c | 5 +++-- include/linux/clocksource.h | 6 ++++-- kernel/time/timekeeping.c | 6 +++--- 6 files changed, 17 insertions(+), 12 deletions(-) diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c index 4990495d7531..a35c661e5e89 100644 --- a/arch/ia64/kernel/time.c +++ b/arch/ia64/kernel/time.c @@ -473,7 +473,7 @@ void update_vsyscall_tz(void) { } -void update_vsyscall(struct timespec *wall, struct clocksource *c) +void update_vsyscall(struct timespec *wall, struct clocksource *c, u32 mult) { unsigned long flags; @@ -481,7 +481,7 @@ void update_vsyscall(struct timespec *wall, struct clocksource *c) /* copy fsyscall clock data */ fsyscall_gtod_data.clk_mask = c->mask; - fsyscall_gtod_data.clk_mult = c->mult; + fsyscall_gtod_data.clk_mult = mult; fsyscall_gtod_data.clk_shift = c->shift; fsyscall_gtod_data.clk_fsys_mmio = c->fsys_mmio; fsyscall_gtod_data.clk_cycle_last = c->cycle_last; diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index a136a11c490d..39713312fbc7 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; diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c index 34162a0b2caa..68e1ecf5ebab 100644 --- a/arch/s390/kernel/time.c +++ b/arch/s390/kernel/time.c @@ -214,7 +214,8 @@ struct clocksource * __init clocksource_default_clock(void) return &clocksource_tod; } -void update_vsyscall(struct timespec *wall_time, struct clocksource *clock) +void update_vsyscall(struct timespec *wall_time, struct clocksource *clock, + u32 mult) { if (clock != &clocksource_tod) return; diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c index 8cb4974ff599..62f39d79b775 100644 --- a/arch/x86/kernel/vsyscall_64.c +++ b/arch/x86/kernel/vsyscall_64.c @@ -73,7 +73,8 @@ void update_vsyscall_tz(void) write_sequnlock_irqrestore(&vsyscall_gtod_data.lock, flags); } -void update_vsyscall(struct timespec *wall_time, struct clocksource *clock) +void update_vsyscall(struct timespec *wall_time, struct clocksource *clock, + u32 mult) { unsigned long flags; @@ -82,7 +83,7 @@ void update_vsyscall(struct timespec *wall_time, struct clocksource *clock) vsyscall_gtod_data.clock.vread = clock->vread; vsyscall_gtod_data.clock.cycle_last = clock->cycle_last; vsyscall_gtod_data.clock.mask = clock->mask; - vsyscall_gtod_data.clock.mult = clock->mult; + vsyscall_gtod_data.clock.mult = mult; vsyscall_gtod_data.clock.shift = clock->shift; vsyscall_gtod_data.wall_time_sec = wall_time->tv_sec; vsyscall_gtod_data.wall_time_nsec = wall_time->tv_nsec; diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index 83d2fbd81b93..95e4995d9987 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -280,10 +280,12 @@ extern struct clocksource * __init __weak clocksource_default_clock(void); extern void clocksource_mark_unstable(struct clocksource *cs); #ifdef CONFIG_GENERIC_TIME_VSYSCALL -extern void update_vsyscall(struct timespec *ts, struct clocksource *c); +extern void +update_vsyscall(struct timespec *ts, struct clocksource *c, u32 mult); extern void update_vsyscall_tz(void); #else -static inline void update_vsyscall(struct timespec *ts, struct clocksource *c) +static inline void +update_vsyscall(struct timespec *ts, struct clocksource *c, u32 mult) { } diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index c3a4e2907eaa..2a6d3e3e2c3e 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -177,7 +177,7 @@ void timekeeping_leap_insert(int leapsecond) { xtime.tv_sec += leapsecond; wall_to_monotonic.tv_sec -= leapsecond; - update_vsyscall(&xtime, timekeeper.clock); + update_vsyscall(&xtime, timekeeper.clock, timekeeper.mult); } #ifdef CONFIG_GENERIC_TIME @@ -337,7 +337,7 @@ int do_settimeofday(struct timespec *tv) timekeeper.ntp_error = 0; ntp_clear(); - update_vsyscall(&xtime, timekeeper.clock); + update_vsyscall(&xtime, timekeeper.clock, timekeeper.mult); write_sequnlock_irqrestore(&xtime_lock, flags); @@ -811,7 +811,7 @@ void update_wall_time(void) update_xtime_cache(nsecs); /* check to see if there is a new clocksource to use */ - update_vsyscall(&xtime, timekeeper.clock); + update_vsyscall(&xtime, timekeeper.clock, timekeeper.mult); } /**