tree: https://github.com/alibaba/cloud-kernel.git linux-next head: e07b931e8ed58352ad4839243454571b6ce59222 commit: a56df460c3ef27d27cbce7f78829ed479e9491aa [293/644] HYGON: x86/cpu: Get cache info and setup cache cpumap for Hygon Dhyana config: x86_64-defconfig (attached as .config) compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project bc2b70982be8f5250cd0082a7190f8b417bd4dfe) 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 x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu git checkout a56df460c3ef27d27cbce7f78829ed479e9491aa # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>, old ones prefixed by <<): arch/x86/kernel/cpu/cacheinfo.c:647:6: warning: no previous prototype for function 'cacheinfo_amd_init_llc_id' [-Wmissing-prototypes] void cacheinfo_amd_init_llc_id(struct cpuinfo_x86 *c, int cpu, u8 node_id) ^ arch/x86/kernel/cpu/cacheinfo.c:647:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void cacheinfo_amd_init_llc_id(struct cpuinfo_x86 *c, int cpu, u8 node_id) ^ static void cacheinfo_hygon_init_llc_id(struct cpuinfo_x86 *c, int cpu, u8 node_id) ^ arch/x86/kernel/cpu/cacheinfo.c:685:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void cacheinfo_hygon_init_llc_id(struct cpuinfo_x86 *c, int cpu, u8 node_id) ^ static 2 warnings generated. vim +/cacheinfo_hygon_init_llc_id +685 arch/x86/kernel/cpu/cacheinfo.c 684 686 { 687 /* 688 * We may have multiple LLCs if L3 caches exist, so check if we 689 * have an L3 cache by looking at the L3 cache CPUID leaf. 690 */ 691 if (!cpuid_edx(0x80000006)) 692 return; 693 694 /* 695 * LLC is at the core complex level. 696 * Core complex ID is ApicId[3] for these processors. 697 */ 698 per_cpu(cpu_llc_id, cpu) = c->apicid >> 3; 699 } 700 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org