diff --git a/include/cmake.mk b/include/cmake.mk
index 900dae1d4a..b66665d20a 100644
--- a/include/cmake.mk
+++ b/include/cmake.mk
@@ -7,8 +7,8 @@ ifneq ($(findstring c,$(OPENWRT_VERBOSE)),)
 endif
 
 CMAKE_BINARY_DIR = $(PKG_BUILD_DIR)$(if $(CMAKE_BINARY_SUBDIR),/$(CMAKE_BINARY_SUBDIR))
-CMAKE_SOURCE_DIR = $(PKG_BUILD_DIR)
-HOST_CMAKE_SOURCE_DIR = $(HOST_BUILD_DIR)
+CMAKE_SOURCE_DIR = $(PKG_BUILD_DIR)$(if $(CMAKE_SOURCE_SUBDIR),/$(CMAKE_SOURCE_SUBDIR))
+HOST_CMAKE_SOURCE_DIR = $(HOST_BUILD_DIR)$(if $(CMAKE_SOURCE_SUBDIR),/$(CMAKE_SOURCE_SUBDIR))
 MAKE_PATH = $(firstword $(CMAKE_BINARY_SUBDIR) .)
 
 ifeq ($(CONFIG_EXTERNAL_TOOLCHAIN),)