diff --git a/include/arch/aarch64/arch.h b/include/arch/aarch64/arch.h
index bc37c94..951f023 100644
--- a/include/arch/aarch64/arch.h
+++ b/include/arch/aarch64/arch.h
@@ -437,6 +437,7 @@
 
 #define ID_AA64PFR1_EL1_SME_SHIFT		U(24)
 #define ID_AA64PFR1_EL1_SME_MASK		ULL(0xf)
+#define ID_AA64PFR1_EL1_SME_WIDTH		U(4)
 #define ID_AA64PFR1_EL1_SME_NOT_SUPPORTED	ULL(0x0)
 #define ID_AA64PFR1_EL1_SME_SUPPORTED		ULL(0x1)
 #define ID_AA64PFR1_EL1_SME2_SUPPORTED		ULL(0x2)