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>
This commit is contained in:
Lin Ming 2009-11-17 13:49:50 +08:00 committed by Thomas Gleixner
parent a9366e61b0
commit 0696b711e4
6 changed files with 17 additions and 12 deletions

View File

@ -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;

View File

@ -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;

View File

@ -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;

View File

@ -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;

View File

@ -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)
{
}

View File

@ -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);
}
/**