diff --git a/Kbuild b/Kbuild
index 68ae6cc..6869ad9 100644
--- a/Kbuild
+++ b/Kbuild
@@ -3246,6 +3246,7 @@
 cppflags-$(CONFIG_WLAN_SEND_DSCP_UP_MAP_TO_FW) += -DWLAN_SEND_DSCP_UP_MAP_TO_FW
 
 cppflags-$(CONFIG_HIF_CPU_PERF_AFFINE_MASK) += -DHIF_CPU_PERF_AFFINE_MASK
+cppflags-$(CONFIG_SMMU_S1_UNMAP) += -DCONFIG_SMMU_S1_UNMAP
 
 KBUILD_CPPFLAGS += $(cppflags-y)