reproduce (this is a W=1 build):
        # https://github.com/avpatel/linux/commit/d715c82481af6e5c6576ae0cb3a17bdb66a9e4ea
        git remote add avpatel https://github.com/avpatel/linux.git
        git fetch --no-tags avpatel riscv_trace_support_v4
        git checkout d715c82481af6e5c6576ae0cb3a17bdb66a9e4ea

        # install riscv cross compiling tool for clang build
        # apt-get install binutils-riscv-linux-gnu
        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=$HOME/0day COMPILER=clang-18 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=riscv olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-18 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash arch/riscv/kernel/