tree: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.9.y head: 073633cdd92bb5dd4ff42f8f0f4b5959fde050e7 commit: fa4bf9f38184ed7ca4916eb64f8c767d1e279c1f [1180/2185] powerpc/64s: flush L1D on kernel entry config: powerpc64-randconfig-r032-20210407 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project c060945b23a1c54d4b2a053ff4b093a2277b303d) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install powerpc64 cross compiling tool for clang build # apt-get install binutils-powerpc64-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.gi... git remote add linux-stable-rc https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git git fetch --no-tags linux-stable-rc linux-4.9.y git checkout fa4bf9f38184ed7ca4916eb64f8c767d1e279c1f # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; Note: the linux-stable-rc/linux-4.9.y HEAD 073633cdd92bb5dd4ff42f8f0f4b5959fde050e7 builds fine. It only hurts bisectibility. All errors (new ones prefixed by >>): arch/powerpc/kernel/setup_64.c:281:13: error: no previous prototype for function 'early_setup' [-Werror,-Wmissing-prototypes] void __init early_setup(unsigned long dt_ptr) ^ arch/powerpc/kernel/setup_64.c:281:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __init early_setup(unsigned long dt_ptr) ^ static arch/powerpc/kernel/setup_64.c:421:13: error: no previous prototype for function 'initialize_cache_info' [-Werror,-Wmissing-prototypes] void __init initialize_cache_info(void) ^ arch/powerpc/kernel/setup_64.c:421:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __init initialize_cache_info(void) ^ static arch/powerpc/kernel/setup_64.c:514:13: error: no previous prototype for function 'irqstack_early_init' [-Werror,-Wmissing-prototypes] void __init irqstack_early_init(void) ^ arch/powerpc/kernel/setup_64.c:514:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __init irqstack_early_init(void) ^ static arch/powerpc/kernel/setup_64.c:563:13: error: no previous prototype for function 'emergency_stack_init' [-Werror,-Wmissing-prototypes] void __init emergency_stack_init(void) ^ arch/powerpc/kernel/setup_64.c:563:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __init emergency_stack_init(void) ^ static void entry_flush_enable(bool enable) ^ arch/powerpc/kernel/setup_64.c:739:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void entry_flush_enable(bool enable) ^ static 5 errors generated. vim +/entry_flush_enable +739 arch/powerpc/kernel/setup_64.c 738 740 { 741 if (enable) { 742 do_entry_flush_fixups(enabled_flush_types); 743 on_each_cpu(do_nothing, NULL, 1); 744 } else { 745 do_entry_flush_fixups(L1D_FLUSH_NONE); 746 } 747 748 entry_flush = enable; 749 } 750 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org