diff --git a/arch/ia64/include/asm/iommu.h b/arch/ia64/include/asm/iommu.h
index 37d41ca5645a..745e095fe82e 100644
--- a/arch/ia64/include/asm/iommu.h
+++ b/arch/ia64/include/asm/iommu.h
@@ -9,7 +9,11 @@ extern void pci_iommu_shutdown(void);
 extern void no_iommu_init(void);
 extern int force_iommu, no_iommu;
 extern int iommu_detected;
+#ifdef	CONFIG_DMAR
 extern int iommu_pass_through;
+#else
+#define iommu_pass_through	(0)
+#endif
 extern void iommu_dma_init(void);
 extern void machvec_init(const char *name);