Commit 157a1a27 authored by Hendrik Brueckner's avatar Hendrik Brueckner Committed by Martin Schwidefsky
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[S390] vdso: use ntp adjusted clock multiplier

Commit "timekeeping: Fix clock_gettime vsyscall time warp" (0696b711)
introduced the new parameter "mult" to update_vsyscall(). This parameter
contains the internal NTP adjusted clock multiplier.

The s390x vdso did not use this adjusted multiplier.  Instead, it used
the constant clock multiplier for gettimeofday() and clock_gettime()
variants.  This may result in observable time warps as explained in
commit 0696b711

.

Make the NTP adjusted clock multiplier available to the s390x vdso
implementation and use it for time calculations.

Cc: <stable@kernel.org>
Signed-off-by: default avatarHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 8821d24c
......@@ -29,6 +29,7 @@ struct vdso_data {
__u32 tz_minuteswest; /* Minutes west of Greenwich 0x30 */
__u32 tz_dsttime; /* Type of dst correction 0x34 */
__u32 ectg_available;
__u32 ntp_mult; /* NTP adjusted multiplier 0x3C */
};
struct vdso_per_cpu_data {
......
......@@ -61,6 +61,7 @@ int main(void)
DEFINE(__VDSO_WTOM_NSEC, offsetof(struct vdso_data, wtom_clock_nsec));
DEFINE(__VDSO_TIMEZONE, offsetof(struct vdso_data, tz_minuteswest));
DEFINE(__VDSO_ECTG_OK, offsetof(struct vdso_data, ectg_available));
DEFINE(__VDSO_NTP_MULT, offsetof(struct vdso_data, ntp_mult));
DEFINE(__VDSO_ECTG_BASE, offsetof(struct vdso_per_cpu_data, ectg_timer_base));
DEFINE(__VDSO_ECTG_USER, offsetof(struct vdso_per_cpu_data, ectg_user_time));
/* constants used by the vdso */
......
......@@ -221,6 +221,7 @@ void update_vsyscall(struct timespec *wall_time, struct clocksource *clock,
vdso_data->xtime_clock_nsec = wall_time->tv_nsec;
vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec;
vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec;
vdso_data->ntp_mult = mult;
smp_wmb();
++vdso_data->tb_update_count;
}
......
......@@ -38,13 +38,13 @@ __kernel_clock_gettime:
sl %r1,__VDSO_XTIME_STAMP+4(%r5)
brc 3,2f
ahi %r0,-1
2: mhi %r0,1000 /* cyc2ns(clock,cycle_delta) */
2: ms %r0,__VDSO_NTP_MULT(%r5) /* cyc2ns(clock,cycle_delta) */
lr %r2,%r0
lhi %r0,1000
l %r0,__VDSO_NTP_MULT(%r5)
ltr %r1,%r1
mr %r0,%r0
jnm 3f
ahi %r0,1000
a %r0,__VDSO_NTP_MULT(%r5)
3: alr %r0,%r2
srdl %r0,12
al %r0,__VDSO_XTIME_NSEC(%r5) /* + xtime */
......@@ -86,13 +86,13 @@ __kernel_clock_gettime:
sl %r1,__VDSO_XTIME_STAMP+4(%r5)
brc 3,12f
ahi %r0,-1
12: mhi %r0,1000 /* cyc2ns(clock,cycle_delta) */
12: ms %r0,__VDSO_NTP_MULT(%r5) /* cyc2ns(clock,cycle_delta) */
lr %r2,%r0
lhi %r0,1000
l %r0,__VDSO_NTP_MULT(%r5)
ltr %r1,%r1
mr %r0,%r0
jnm 13f
ahi %r0,1000
a %r0,__VDSO_NTP_MULT(%r5)
13: alr %r0,%r2
srdl %r0,12
al %r0,__VDSO_XTIME_NSEC(%r5) /* + xtime */
......
......@@ -35,13 +35,13 @@ __kernel_gettimeofday:
sl %r1,__VDSO_XTIME_STAMP+4(%r5)
brc 3,3f
ahi %r0,-1
3: mhi %r0,1000 /* cyc2ns(clock,cycle_delta) */
3: ms %r0,__VDSO_NTP_MULT(%r5) /* cyc2ns(clock,cycle_delta) */
st %r0,24(%r15)
lhi %r0,1000
l %r0,__VDSO_NTP_MULT(%r5)
ltr %r1,%r1
mr %r0,%r0
jnm 4f
ahi %r0,1000
a %r0,__VDSO_NTP_MULT(%r5)
4: al %r0,24(%r15)
srdl %r0,12
al %r0,__VDSO_XTIME_NSEC(%r5) /* + xtime */
......
......@@ -36,7 +36,7 @@ __kernel_clock_gettime:
stck 48(%r15) /* Store TOD clock */
lg %r1,48(%r15)
sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
mghi %r1,1000
msgf %r1,__VDSO_NTP_MULT(%r5) /* * NTP adjustment */
srlg %r1,%r1,12 /* cyc2ns(clock,cycle_delta) */
alg %r1,__VDSO_XTIME_NSEC(%r5) /* + xtime */
lg %r0,__VDSO_XTIME_SEC(%r5)
......@@ -64,7 +64,7 @@ __kernel_clock_gettime:
stck 48(%r15) /* Store TOD clock */
lg %r1,48(%r15)
sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
mghi %r1,1000
msgf %r1,__VDSO_NTP_MULT(%r5) /* * NTP adjustment */
srlg %r1,%r1,12 /* cyc2ns(clock,cycle_delta) */
alg %r1,__VDSO_XTIME_NSEC(%r5) /* + xtime */
lg %r0,__VDSO_XTIME_SEC(%r5)
......
......@@ -31,7 +31,7 @@ __kernel_gettimeofday:
stck 48(%r15) /* Store TOD clock */
lg %r1,48(%r15)
sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
mghi %r1,1000
msgf %r1,__VDSO_NTP_MULT(%r5) /* * NTP adjustment */
srlg %r1,%r1,12 /* cyc2ns(clock,cycle_delta) */
alg %r1,__VDSO_XTIME_NSEC(%r5) /* + xtime.tv_nsec */
lg %r0,__VDSO_XTIME_SEC(%r5) /* xtime.tv_sec */
......
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