diff --git a/arch/s390/boot/physmem_info.c b/arch/s390/boot/physmem_info.c
index 1f2ca5435838..0ebb2174713f 100644
--- a/arch/s390/boot/physmem_info.c
+++ b/arch/s390/boot/physmem_info.c
@@ -141,7 +141,7 @@ static int tprot(unsigned long addr)
 
 static unsigned long search_mem_end(void)
 {
-	unsigned long range = 1 << (MAX_PHYSMEM_BITS - 20); /* in 1MB blocks */
+	unsigned long range = 1UL << (MAX_PHYSMEM_BITS - 20); /* in 1MB blocks */
 	unsigned long offset = 0;
 	unsigned long pivot;