reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # install arm64 cross compiling tool for clang build
        # apt-get install binutils-aarch64-linux-gnu
        # https://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux.git/commit/?id=f2c77f6e41e68e1b24c165acbf6d4da6b3117e23
        git remote add iommu https://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux.git
        git fetch --no-tags iommu arm/smmu/updates
        git checkout f2c77f6e41e68e1b24c165acbf6d4da6b3117e23
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-16 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=arm64 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-16 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=arm64 SHELL=/bin/bash drivers/iommu/arm/arm-smmu-v3/