reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://github.com/norov/linux/commit/23228578687634d7bb126bd87e3750780f409e66
        git remote add norov https://github.com/norov/linux
        git fetch --no-tags norov bitmap-split
        git checkout 23228578687634d7bb126bd87e3750780f409e66
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-13.2.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-13.2.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash drivers/misc/cxl/