diff --git a/arch/s390/kernel/diag.c b/arch/s390/kernel/diag.c
index 8dee9aa0ec95..9f33dcecbffa 100644
--- a/arch/s390/kernel/diag.c
+++ b/arch/s390/kernel/diag.c
@@ -215,16 +215,16 @@ int diag204(unsigned long subcode, unsigned long size, void *addr)
 {
 	if (addr) {
 		if (WARN_ON_ONCE(!is_vmalloc_addr(addr)))
-			return -1;
+			return -EINVAL;
 		if (WARN_ON_ONCE(!IS_ALIGNED((unsigned long)addr, PAGE_SIZE)))
-			return -1;
+			return -EINVAL;
 	}
 	if ((subcode & DIAG204_SUBCODE_MASK) == DIAG204_SUBC_STIB4)
 		addr = (void *)pfn_to_phys(vmalloc_to_pfn(addr));
 	diag_stat_inc(DIAG_STAT_X204);
 	size = __diag204(&subcode, size, addr);
 	if (subcode)
-		return -1;
+		return -EOPNOTSUPP;
 	return size;
 }
 EXPORT_SYMBOL(diag204);