[S390] add generic atomic64 support for 31 bit

Performance counters need 64 bit atomic operations.
To keep the patch small we use the simple generic atomic64_t implementation.
The native implementation follows with the next kernel.

Fixes this build bug:

In file included from kernel/sched.c:42:
include/linux/perf_counter.h:427: error: expected specifier-qualifier-list before 'atomic64_t'

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 4cd12b5202af..f46a1b50ddee 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -95,6 +95,7 @@ config S390
         select HAVE_ARCH_TRACEHOOK
         select INIT_ALL_POSSIBLE
         select HAVE_PERF_COUNTERS
+        select GENERIC_ATOMIC64 if !64BIT
 
 config SCHED_OMIT_FRAME_POINTER
         bool