[S390] vdso: use ntp adjusted clock multiplier

Commit "timekeeping: Fix clock_gettime vsyscall time warp" (0696b711e)
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 0696b711e.

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>

diff --git a/arch/s390/include/asm/vdso.h b/arch/s390/include/asm/vdso.h
index 4a76d9480cce533dd5b95d658acb0c6ecd6808e9..533f35751aeb9ad130af57e0f6cf551cfe873862 100644 (file)
--- 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
index 08db736dded00192b435129698a6cf5efee420ac..a09408952ed0691a41c0bfcfefad321a7c79c865 100644 (file)
--- 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
index fba6dec156bf4c27b1f469b9e07543a05d21ded8..d906bf19c14a2a309d7aca26d0903a5503987559 100644 (file)
--- 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
index 4a98909a83100c40fe5440822302a453403dcf4a..969643954273c2e1a3c75fe045985d3649e661c3 100644 (file)
--- 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
index ad8acfc949fbdb5d0a7f59375bf567770780686e..2d3633175e3be520850ad6b48b30e94c88058072 100644 (file)
--- 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
index 49106c6e6f88336ab9e3d641e97ba25b8179df04..f40467884a03722c668b388591e976f71be8961d 100644 (file)
--- 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
index f873e75634e1b1041a4df34caa9083c604ce5e45..36ee674722ec3a76b3439fe78752f024ba5ba434 100644 (file)
--- 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 */