s390/vdso: fix initializing and updating of vdso_data

Li Wang reported that clock_gettime(CLOCK_MONOTONIC_RAW, ...) returns
incorrect values when time is provided via vdso instead of system call:

vdso_ts_nsec = 4484351380985507, vdso_ts.tv_sec = 4484351, vdso_ts.tv_nsec = 380985507
sys_ts_nsec  = 1446923235377, sys_ts.tv_sec  = 1446, sys_ts.tv_nsec  = 923235377

Within the s390 specific vdso function __arch_get_hw_counter() reads
tod clock steering values from the arch_data member of the passed in
vdso_data structure.

Problem is that only for the CS_HRES_COARSE vdso_data arch_data is
initialized and gets updated. The CS_RAW specific vdso_data does not
contain any valid tod_clock_steering information, which explains the
different values.

Fix this by initializing and updating all vdso_datas.

Reported-by: Li Wang <liwang@redhat.com>
Tested-by: Li Wang <liwang@redhat.com>
Fixes: 1ba2d6c0fd4e ("s390/vdso: simplify __arch_get_hw_counter()")
Link: https://lore.kernel.org/linux-s390/YFnxr1ZlMIOIqjfq@osiris
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c
index e37285a5101be15e0126a41733599f724df9e22d..326cb8f75f58ef21cc73ba7c244103c8e13e509a 100644 (file)
--- a/arch/s390/kernel/time.c
+++ b/arch/s390/kernel/time.c
@@ -80,10 +80,12 @@ void __init time_early_init(void)
 {
        struct ptff_qto qto;
        struct ptff_qui qui;
+       int cs;
 
        /* Initialize TOD steering parameters */
        tod_steering_end = tod_clock_base.tod;
-       vdso_data->arch_data.tod_steering_end = tod_steering_end;
+       for (cs = 0; cs < CS_BASES; cs++)
+               vdso_data[cs].arch_data.tod_steering_end = tod_steering_end;
 
        if (!test_facility(28))
                return;
@@ -366,6 +368,7 @@ static void clock_sync_global(unsigned long delta)
 {
        unsigned long now, adj;
        struct ptff_qto qto;
+       int cs;
 
        /* Fixup the monotonic sched clock. */
        tod_clock_base.eitod += delta;
@@ -381,8 +384,10 @@ static void clock_sync_global(unsigned long delta)
                panic("TOD clock sync offset %li is too large to drift\n",
                      tod_steering_delta);
        tod_steering_end = now + (abs(tod_steering_delta) << 15);
-       vdso_data->arch_data.tod_steering_end = tod_steering_end;
-       vdso_data->arch_data.tod_steering_delta = tod_steering_delta;
+       for (cs = 0; cs < CS_BASES; cs++) {
+               vdso_data[cs].arch_data.tod_steering_end = tod_steering_end;
+               vdso_data[cs].arch_data.tod_steering_delta = tod_steering_delta;
+       }
 
        /* Update LPAR offset. */
        if (ptff_query(PTFF_QTO) && ptff(&qto, sizeof(qto), PTFF_QTO) == 0)