reproduce:
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # apt-get install sparse
        # sparse version: v0.6.4-66-g0196afe1-dirty
        # https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/commit/?id=7da51af9125c624318c8099de13c5ddefd47e9e8
        git remote add arm-perf https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git
        git fetch --no-tags arm-perf for-joerg/arm-smmu/updates
        git checkout 7da51af9125c624318c8099de13c5ddefd47e9e8
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        ~/lkp-tests/kbuild/make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=arm64 olddefconfig
        ~/lkp-tests/kbuild/make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=arm64 SHELL=/bin/bash drivers/iommu/arm/arm-smmu-v3/