reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux.git/commit/?id=5592bb2b6fab7adb19ebedac49d65820d92c8b04
        git remote add axboe https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux.git
        git fetch --no-tags axboe io_uring-cbpf-restrictions
        git checkout 5592bb2b6fab7adb19ebedac49d65820d92c8b04

        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=$HOME/0day COMPILER=gcc-8.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-8.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash