scripts/kconfig/Makefile implements make targets related to kernel configuration. make with one of these targets, the target name is mapped to the corresponding option name of scripts/kconfig/conf. cross_compiling is not defined, the Makefile adds the following files to KCONFIG_DEFCONFIG_LIST: /lib/modules/$(kernel-relase)/.config
/etc/kernel-config
/boot/config-$(kernel-release) arch/$SRCARCH/configs/$(KBUILD_DEFCONFIG) to this list.