tree:   https://github.com/c-sky/csky-linux v5.14-rc2-of-delay-cpu-available
head:   f6c22a2278708ce7227c42294e351ff53e8b279a
commit: 04be54eab2e8df9ac47f9d7e6ede22953f9f78e2 [3/5] riscv: pgtable: Add "PBMT" extension supported
config: riscv-allmodconfig (attached as .config)
compiler: riscv64-linux-gcc (GCC) 10.3.0
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
        # https://github.com/c-sky/csky-linux/commit/04be54eab2e8df9ac47f9d7e6ede22953f9f78e2
        git remote add csky-linux https://github.com/c-sky/csky-linux
        git fetch --no-tags csky-linux v5.14-rc2-of-delay-cpu-available
        git checkout 04be54eab2e8df9ac47f9d7e6ede22953f9f78e2
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-10.3.0 make.cross ARCH=riscv 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> arch/riscv/mm/init.c:905:13: warning: no previous prototype for 'pbmt_init' [-Wmissing-prototypes]
     905 | void __init pbmt_init(void)
         |             ^~~~~~~~~


vim +/pbmt_init +905 arch/riscv/mm/init.c

   903	
   904	#ifdef CONFIG_64BIT
 > 905	void __init pbmt_init(void)
   906	{
   907		struct device_node *cpu;
   908	
   909		cpu = of_find_node_by_path("/cpus");
   910		if (!cpu || of_property_read_bool(cpu, "pbmt-extension"))
   911			return;
   912	
   913		memset(&__riscv_pbmt, 0, sizeof(__riscv_pbmt));
   914	}
   915	#endif
   916	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org