reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git/commit/?id=96ce888c02ed7cf7278c4d4d14bab67c1db4b673
        git remote add namhyung-perf https://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git
        git fetch --no-tags namhyung-perf bpf/slab-iter-v4
        git checkout 96ce888c02ed7cf7278c4d4d14bab67c1db4b673
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-14.1.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=microblaze olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-14.1.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=microblaze SHELL=/bin/bash mm/