Hi Jiaxun, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 2cc3c4b3c2e9c99e90aaf19cd801ff2c160f283c commit: 71e2f4dd5a65bd8dbca0b77661e75eea471168f8 MIPS: Fork loongson2ef from loongson64 date: 10 months ago config: mips-randconfig-r001-20200817 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project ab9fc8bae805c785066779e76e7846aabad5609e) 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 mips cross compiling tool for clang build # apt-get install binutils-mips-linux-gnu git checkout 71e2f4dd5a65bd8dbca0b77661e75eea471168f8 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=mips If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): clang-12: warning: argument unused during compilation: '-mno-branch-likely' [-Wunused-command-line-argument] error: unknown target CPU 'r4600' note: valid target CPU values are: mips1, mips2, mips3, mips4, mips5, mips32, mips32r2, mips32r3, mips32r5, mips32r6, mips64, mips64r2, mips64r3, mips64r5, mips64r6, octeon, octeon+, p5600 clang-12: warning: argument unused during compilation: '-mno-branch-likely' [-Wunused-command-line-argument] In file included from arch/mips/kernel/asm-offsets.c:12: In file included from include/linux/compat.h:15: In file included from include/linux/socket.h:8: In file included from include/linux/uio.h:10: In file included from include/crypto/hash.h:11: In file included from include/linux/crypto.h:19: In file included from include/linux/slab.h:15: In file included from include/linux/gfp.h:9: return cpu_to_node(raw_smp_processor_id()); ^ arch/mips/include/asm/mach-loongson64/topology.h:7:27: note: expanded from macro 'cpu_to_node' #define cpu_to_node(cpu) (cpu_logical_map(cpu) >> 2) ^ In file included from arch/mips/kernel/asm-offsets.c:12: In file included from include/linux/compat.h:15: In file included from include/linux/socket.h:8: In file included from include/linux/uio.h:10: In file included from include/crypto/hash.h:11: In file included from include/linux/crypto.h:19: In file included from include/linux/slab.h:15: In file included from include/linux/gfp.h:9: include/linux/topology.h:193:9: error: implicit declaration of function 'cpu_logical_map' [-Werror,-Wimplicit-function-declaration] return cpu_to_node(cpu); ^ arch/mips/include/asm/mach-loongson64/topology.h:7:27: note: expanded from macro 'cpu_to_node' #define cpu_to_node(cpu) (cpu_logical_map(cpu) >> 2) ^ In file included from arch/mips/kernel/asm-offsets.c:12: In file included from include/linux/compat.h:15: In file included from include/linux/socket.h:8: In file included from include/linux/uio.h:10: In file included from include/crypto/hash.h:11: In file included from include/linux/crypto.h:19: In file included from include/linux/slab.h:15: In file included from include/linux/gfp.h:9: include/linux/topology.h:227:25: error: implicit declaration of function 'cpu_logical_map' [-Werror,-Wimplicit-function-declaration] return cpumask_of_node(cpu_to_node(cpu)); ^ arch/mips/include/asm/mach-loongson64/topology.h:7:27: note: expanded from macro 'cpu_to_node' #define cpu_to_node(cpu) (cpu_logical_map(cpu) >> 2) ^ arch/mips/kernel/asm-offsets.c:26:6: warning: no previous prototype for function 'output_ptreg_defines' [-Wmissing-prototypes] void output_ptreg_defines(void) ^ arch/mips/kernel/asm-offsets.c:26:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void output_ptreg_defines(void) ^ static arch/mips/kernel/asm-offsets.c:78:6: warning: no previous prototype for function 'output_task_defines' [-Wmissing-prototypes] void output_task_defines(void) ^ arch/mips/kernel/asm-offsets.c:78:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void output_task_defines(void) ^ static arch/mips/kernel/asm-offsets.c:93:6: warning: no previous prototype for function 'output_thread_info_defines' [-Wmissing-prototypes] void output_thread_info_defines(void) ^ arch/mips/kernel/asm-offsets.c:93:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void output_thread_info_defines(void) ^ static arch/mips/kernel/asm-offsets.c:110:6: warning: no previous prototype for function 'output_thread_defines' [-Wmissing-prototypes] void output_thread_defines(void) ^ arch/mips/kernel/asm-offsets.c:110:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void output_thread_defines(void) ^ static arch/mips/kernel/asm-offsets.c:181:6: warning: no previous prototype for function 'output_mm_defines' [-Wmissing-prototypes] void output_mm_defines(void) ^ arch/mips/kernel/asm-offsets.c:181:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void output_mm_defines(void) ^ static arch/mips/kernel/asm-offsets.c:242:6: warning: no previous prototype for function 'output_sc_defines' [-Wmissing-prototypes] void output_sc_defines(void) ^ arch/mips/kernel/asm-offsets.c:242:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void output_sc_defines(void) ^ static arch/mips/kernel/asm-offsets.c:255:6: warning: no previous prototype for function 'output_signal_defined' [-Wmissing-prototypes] void output_signal_defined(void) ^ arch/mips/kernel/asm-offsets.c:255:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void output_signal_defined(void) ^ static arch/mips/kernel/asm-offsets.c:322:6: warning: no previous prototype for function 'output_pbe_defines' [-Wmissing-prototypes] void output_pbe_defines(void) ^ arch/mips/kernel/asm-offsets.c:322:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void output_pbe_defines(void) ^ static 8 warnings and 3 errors generated. make[2]: *** [scripts/Makefile.build:99: arch/mips/kernel/asm-offsets.s] Error 1 make[2]: Target 'missing-syscalls' not remade because of errors. make[1]: *** [arch/mips/Makefile:414: archprepare] Error 2 make[1]: Target 'prepare' not remade because of errors. make: *** [Makefile:179: sub-make] Error 2 make: Target 'prepare' not remade because of errors. # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout 71e2f4dd5a65bd8dbca0b77661e75eea471168f8 vim +/cpu_logical_map +119 include/linux/topology.h 7281201922a006 Lee Schermerhorn 2010-05-26 114 7281201922a006 Lee Schermerhorn 2010-05-26 115 /* Returns the number of the current Node. */ 7281201922a006 Lee Schermerhorn 2010-05-26 116 #ifndef numa_node_id 7281201922a006 Lee Schermerhorn 2010-05-26 117 static inline int numa_node_id(void) 7281201922a006 Lee Schermerhorn 2010-05-26 118 { 7281201922a006 Lee Schermerhorn 2010-05-26 @119 return cpu_to_node(raw_smp_processor_id()); 7281201922a006 Lee Schermerhorn 2010-05-26 120 } 7281201922a006 Lee Schermerhorn 2010-05-26 121 #endif 7281201922a006 Lee Schermerhorn 2010-05-26 122 :::::: The code at line 119 was first introduced by commit :::::: 7281201922a0063fa60804ce39c277fc98142a47 numa: add generic percpu var numa_node_id() implementation :::::: TO: Lee Schermerhorn <lee.schermerhorn(a)hp.com&gt; :::::: CC: Linus Torvalds <torvalds(a)linux-foundation.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org