diff --git a/include/efi.h b/include/efi.h
index d07187c..3d58780 100644
--- a/include/efi.h
+++ b/include/efi.h
@@ -30,8 +30,11 @@
 
 #define EFI_BITS_PER_LONG	BITS_PER_LONG
 
-/* With 64-bit EFI stub, EFI_BITS_PER_LONG has to be 64 */
-#ifdef CONFIG_EFI_STUB_64BIT
+/*
+ * With 64-bit EFI stub, EFI_BITS_PER_LONG has to be 64. EFI_STUB is set
+ * in lib/efi/Makefile, when building the stub.
+ */
+#if defined(CONFIG_EFI_STUB_64BIT) && defined(EFI_STUB)
 #undef EFI_BITS_PER_LONG
 #define EFI_BITS_PER_LONG	64
 #endif