reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # install s390 cross compiling tool for clang build
        # apt-get install binutils-s390x-linux-gnu
        # https://github.com/sbates130272/linux-p2pmem/commit/bbb07dc00a3bb220aa0570177a0716d7b48bac7e
        git remote add sbates130272-p2pmem https://github.com/sbates130272/linux-p2pmem.git
        git fetch --no-tags sbates130272-p2pmem dev/amd-dma-buf
        git checkout bbb07dc00a3bb220aa0570177a0716d7b48bac7e
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-18 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=s390 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-18 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash drivers/gpu/drm/amd/amdgpu/