[S390] vdso: use ntp adjusted clock multiplier

Commit "timekeeping: Fix clock_gettime vsyscall time warp" (0696b71) 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 0696b71. 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: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
git-mirror · Apr 22, 2010 · 157a1a2 · 157a1a2
1 parent 8821d24
commit 157a1a2
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Showing 7 changed files with 15 additions and 12 deletions.
diff --git a/arch/s390/include/asm/vdso.h b/arch/s390/include/asm/vdso.h
@@ -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 {

diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
@@ -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 */

diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c
@@ -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;
 }

diff --git a/arch/s390/kernel/vdso32/clock_gettime.S b/arch/s390/kernel/vdso32/clock_gettime.S
@@ -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 */

diff --git a/arch/s390/kernel/vdso32/gettimeofday.S b/arch/s390/kernel/vdso32/gettimeofday.S
@@ -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 */

diff --git a/arch/s390/kernel/vdso64/clock_gettime.S b/arch/s390/kernel/vdso64/clock_gettime.S
@@ -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)

diff --git a/arch/s390/kernel/vdso64/gettimeofday.S b/arch/s390/kernel/vdso64/gettimeofday.S
@@ -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 */