tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: e9919e11e219eaa5e8041b7b1a196839143e9125 commit: 2875fe0561569f82d0e63658ccf0d11ce7da8922 RISC-V: Add cpu_ops and modify default booting method date: 4 months ago config: riscv-randconfig-r011-20200715 (attached as .config) compiler: riscv32-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 2875fe0561569f82d0e63658ccf0d11ce7da8922 # 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: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): 109 | int start_secondary_cpu(int cpu, struct task_struct *tidle) | ^~~~~~~~~~~~~~~~~~~ arch/riscv/kernel/smpboot.c:146:34: warning: no previous prototype for 'smp_callin' [-Wmissing-prototypes] 146 | asmlinkage __visible void __init smp_callin(void) | ^~~~~~~~~~ vim +/start_secondary_cpu +109 arch/riscv/kernel/smpboot.c 108 110 { 111 if (cpu_ops[cpu]->cpu_start) 112 return cpu_ops[cpu]->cpu_start(cpu, tidle); 113 114 return -EOPNOTSUPP; 115 } 116 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org