diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 1da0d82444f9a9e0ff87ae22b40b8e758131b44f..1c0ec16effbb75a30e719e030749cd9919919aed 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -101,7 +101,7 @@
 
 /* Register bits */
 #define ARM_32_LPAE_TCR_EAE		(1 << 31)
-#define ARM_64_LPAE_S2_TCR_RES1		(1 << 31)
+#define ARM_64_LPAE_S2_TCR_RES1		(1U << 31)
 
 #define ARM_LPAE_TCR_EPD1		(1 << 23)