diff --git a/arch/x86/include/asm/mmu.h b/arch/x86/include/asm/mmu.h
index 80a1dee5bea5ec67bb77adf6db286f471d8006e8..aeff3e89b222edc08d31f122dc7008a0cc8466a9 100644
--- a/arch/x86/include/asm/mmu.h
+++ b/arch/x86/include/asm/mmu.h
@@ -13,6 +13,12 @@ typedef struct {
 	int size;
 	struct mutex lock;
 	void *vdso;
+
+#ifdef CONFIG_X86_64
+	/* True if mm supports a task running in 32 bit compatibility mode. */
+	unsigned short ia32_compat;
+#endif
+
 } mm_context_t;
 
 #ifdef CONFIG_SMP