reproduce (this is a W=1 build):
        # https://github.com/zen-kernel/zen-kernel/commit/cd32ade31c0d6aa492e3af6249fa039521129a0d
        git remote add zen https://github.com/zen-kernel/zen-kernel
        git fetch --no-tags zen 6.18/zen-sauce
        git checkout cd32ade31c0d6aa492e3af6249fa039521129a0d

        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # apt-get install sparse
        # sparse version: v0.6.4-73-gfbdde312

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-8.5.0 ~/lkp-tests/kbuild/make.cross W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=s390 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-8.5.0 ~/lkp-tests/kbuild/make.cross W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=s390 SHELL=/bin/bash arch/s390/pci/ drivers/gpu/drm/amd/amdgpu/ mm/