tree: https://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git for-next head: 44ab661dd29db5956b73ae7553865604f9d725fa commit: 71e26d08ff3806a4e0198afb3a9858d3bb1b3c9c [8/11] riscv: Add SW single-step support for KDB config: riscv-allyesconfig (attached as .config) compiler: riscv64-linux-gcc (GCC) 9.3.0 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 git checkout 71e26d08ff3806a4e0198afb3a9858d3bb1b3c9c # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=riscv If you fix the issue, kindly add following tag as appropriate Reported-by: kbuild test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>, old ones prefixed by <<): arch/riscv/kernel/kgdb.c:47:5: warning: no previous prototype for 'decode_register_index' [-Wmissing-prototypes] 47 | int decode_register_index(unsigned long opcode, int offset) | ^~~~~~~~~~~~~~~~~~~~~ << from arch/riscv/kernel/kgdb.c:9: 52 | int decode_register_index_short(unsigned long opcode, int offset) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~ arch/riscv/kernel/kgdb.c:58:5: warning: no previous prototype for 'get_step_address' [-Wmissing-prototypes] 58 | int get_step_address(struct pt_regs *regs, unsigned long *next_addr) | ^~~~~~~~~~~~~~~~ arch/riscv/kernel/kgdb.c:139:5: warning: no previous prototype for 'do_single_step' [-Wmissing-prototypes] 139 | int do_single_step(struct pt_regs *regs) | ^~~~~~~~~~~~~~ arch/riscv/kernel/kgdb.c:276:6: warning: no previous prototype for 'kgdb_arch_handle_qxfer_pkt' [-Wmissing-prototypes] 276 | void kgdb_arch_handle_qxfer_pkt(char *remcom_in_buffer, | ^~~~~~~~~~~~~~~~~~~~~~~~~~ arch/riscv/kernel/kgdb.c:323:5: warning: no previous prototype for 'kgdb_riscv_kgdbbreak' [-Wmissing-prototypes] 323 | int kgdb_riscv_kgdbbreak(unsigned long addr) | ^~~~~~~~~~~~~~~~~~~~ In file included from arch/riscv/include/asm/kgdb.h:109, from include/linux/kgdb.h:20, from arch/riscv/kernel/kgdb.c:9: arch/riscv/include/asm/gdb_xml.h:7:19: warning: 'riscv_gdb_stub_feature' defined but not used [-Wunused-const-variable=] 7 | static const char riscv_gdb_stub_feature[64] = | ^~~~~~~~~~~~~~~~~~~~~~ vim +/decode_register_index_short +52 arch/riscv/kernel/kgdb.c 46 48 { 49 return (opcode >> offset) & 0x1F; 50 } 51 53 { 54 return ((opcode >> offset) & 0x7) + 8; 55 } 56 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org