reproduce (this is a W=1 build):
        # https://github.com/davidhildenbrand/linux/commit/bdd0e7f6c7062ca47a16ca208ab1de07161ec049
        git remote add davidhildenbrand https://github.com/davidhildenbrand/linux
        git fetch --no-tags davidhildenbrand folded_pgtable
        git checkout bdd0e7f6c7062ca47a16ca208ab1de07161ec049

        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=nios2 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=nios2 SHELL=/bin/bash arch/nios2/mm/