[S390] boot cputime accounting

Start the cpu time accounting very early to catch the cpu time spent
for the initial kernel setup. To make the output of /proc/uptime
match the sum of all cpu accounting values of the boot cpu reset
xtime and wall_to_monotonic to sane values based on the TOD clock.
The values set by timekeeping_init are off by up to a second.

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

1 files changed, 7 insertions, 1 deletions

diff --git a/arch/s390/kernel/head.S b/arch/s390/kernel/head.S
index 16f8975325ed..bba14494ee00 100644
--- a/arch/s390/kernel/head.S
+++ b/arch/s390/kernel/head.S
@@ -473,7 +473,10 @@ startup:basr	%r13,0			# get base
         xc      0x300(256),0x300
         l       %r1,5f-.LPG0(%r13)
         stck    0(%r1)
-
+        spt     6f-.LPG0(%r13)
+        mvc     __LC_LAST_UPDATE_CLOCK(8),0(%r1)
+        mvc     __LC_LAST_UPDATE_TIMER(8),6f-.LPG0(%r13)
+        mvc     __LC_EXIT_TIMER(8),5f-.LPG0(%r13)
 #ifndef CONFIG_MARCH_G5
         # check processor version against MARCH_{G5,Z900,Z990,Z9_109,Z10}
         stidp   __LC_CPUID              # store cpuid
@@ -500,8 +503,11 @@ startup:basr	%r13,0			# get base
 
         l       %r13,4f-.LPG0(%r13)
         b       0(%r13)
+        .align  4
 4:      .long   startup_continue
 5:      .long   sched_clock_base_cc
+        .align  8
+6:      .long   0x7fffffff,0xffffffff
 
 #
 # params at 10400 (setup.h)