diff --git a/include/efi_loader.h b/include/efi_loader.h
index f759cfe..f470bbd 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -561,7 +561,7 @@
  * @size:	size in bytes
  * Return:	size in pages
  */
-#define efi_size_in_pages(size) ((size + EFI_PAGE_MASK) >> EFI_PAGE_SHIFT)
+#define efi_size_in_pages(size) (((size) + EFI_PAGE_MASK) >> EFI_PAGE_SHIFT)
 /* Generic EFI memory allocator, call this to get memory */
 void *efi_alloc(uint64_t len, int memory_type);
 /* More specific EFI memory allocator, called by EFI payloads */