reproduce:
        git remote add arnd-asm-generic https://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git
        git fetch arnd-asm-generic master
        git checkout arnd-asm-generic/master
        b4 shazam https://lore.kernel.org/r/20250620111610.52750-2-cp0613@linux.alibaba.com
        make menuconfig
        # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS, CONFIG_WARN_ABI_ERRORS
        # install Sphinx 3.4.3
        make htmldocs