[S390] add read_persistent_clock

Add a read_persistent_clock function that does not just return 0.
Since timekeeping_init calls the function before time_init has been
called move reset_tod_clock to early.c to make sure that the TOD
clock is running when read_persistent_clock is invoked.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/arch/s390/kernel/head.S b/arch/s390/kernel/head.S
index 1046c2c9f8d1..16f8975325ed 100644
--- a/arch/s390/kernel/head.S
+++ b/arch/s390/kernel/head.S
@@ -471,6 +471,8 @@ startup:basr	%r13,0			# get base
 .LPG0:
         xc      0x200(256),0x200        # partially clear lowcore
         xc      0x300(256),0x300
+        l       %r1,5f-.LPG0(%r13)
+        stck    0(%r1)
 
 #ifndef CONFIG_MARCH_G5
         # check processor version against MARCH_{G5,Z900,Z990,Z9_109,Z10}
@@ -496,9 +498,10 @@ startup:basr	%r13,0			# get base
         brct    %r0,0b
 #endif
 
-        l       %r13,0f-.LPG0(%r13)
+        l       %r13,4f-.LPG0(%r13)
         b       0(%r13)
-0:      .long   startup_continue
+4:      .long   startup_continue
+5:      .long   sched_clock_base_cc
 
 #
 # params at 10400 (setup.h)