diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
index 9ae483ec1e56..185bc5b0faf7 100644
--- a/arch/arm64/tools/sysreg
+++ b/arch/arm64/tools/sysreg
@@ -98,7 +98,9 @@ Enum	63	FA64
 	0b1	IMP
 EndEnum
 Res0	62:60
-Field	59:56	SMEver
+Enum	59:56	SMEver
+	0b0000	IMP
+EndEnum
 Enum	55:52	I16I64
 	0b0000	NI
 	0b1111	IMP