diff --git a/arch/powerpc/mm/mmap.c b/arch/powerpc/mm/mmap.c
index 005aa8a44915..9dbd2a733d6b 100644
--- a/arch/powerpc/mm/mmap.c
+++ b/arch/powerpc/mm/mmap.c
@@ -66,7 +66,7 @@ unsigned long arch_mmap_rnd(void)
 	if (is_32bit_task())
 		shift = mmap_rnd_compat_bits;
 #endif
-	rnd = get_random_long() % (1 << shift);
+	rnd = get_random_long() % (1ul << shift);
 
 	return rnd << PAGE_SHIFT;
 }