reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # install powerpc cross compiling tool for clang build
        # apt-get install binutils-powerpc-linux-gnu
        # https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git/commit/?id=9bddfc061dffa3ca19b6e971ef1f1281458ee8a3
        git remote add axboe-block https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git
        git fetch --no-tags axboe-block rw_iter
        git checkout 9bddfc061dffa3ca19b6e971ef1f1281458ee8a3
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-14 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-14 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash arch/powerpc/platforms/52xx/ drivers/bus/ drivers/pci/switch/ drivers/soc/fsl/ drivers/staging/axis-fifo/ drivers/uio/ drivers/usb/misc/ drivers/watchdog/ kernel/dma/ kernel/irq/ kernel/time/ kernel/trace/ lib/xz/ mm/