tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 8db5efb83fa99e81c3f8dee92a6589b251f117f3 commit: baec970aa5ba11099ad7a91773350c91fb2113f0 mips: Add N64 machine type date: 3 months ago config: mips-randconfig-r035-20210424 (attached as .config) compiler: mips-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 # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=baec970aa5ba11099ad7a91773350c91fb2113f0 git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout baec970aa5ba11099ad7a91773350c91fb2113f0 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross W=1 ARCH=mips If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All warnings (new ones prefixed by >>): >> arch/mips/boot/compressed/ashldi3.c:9:19: warning: no previous prototype for '__ashldi3' [-Wmissing-prototypes] 9 | long long notrace __ashldi3(long long u, word_type b) | ^~~~~~~~~ -- >> arch/mips/boot/compressed/bswapsi.c:5:22: warning: no previous prototype for '__bswapsi2' [-Wmissing-prototypes] 5 | unsigned int notrace __bswapsi2(unsigned int u) | ^~~~~~~~~~ --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org