[S390] memory detection: fix off by one bug.

diag 260 returns the address of the last addressable byte and not the
size of memory. Since we want the size we have to add 1 to the return
value.
Disable diag 260 for non z/Arch mode since it doesn't work there
anyway.

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

1 files changed, 8 insertions, 2 deletions

diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index afca1c6f4d21..5e47936573f2 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -141,9 +141,9 @@ static noinline __init void detect_machine_type(void)
                 machine_flags |= 4;
 }
 
+#ifdef CONFIG_64BIT
 static noinline __init int memory_fast_detect(void)
 {
-
         unsigned long val0 = 0;
         unsigned long val1 = 0xc;
         int ret = -ENOSYS;
@@ -161,9 +161,15 @@ static noinline __init int memory_fast_detect(void)
         if (ret || val0 != val1)
                 return -ENOSYS;
 
-        memory_chunk[0].size = val0;
+        memory_chunk[0].size = val0 + 1;
         return 0;
 }
+#else
+static inline int memory_fast_detect(void)
+{
+        return -ENOSYS;
+}
+#endif
 
 #define ADDR2G  (1UL << 31)