[kbuild-all] [linux-next:master 9638/12117] arch/mips/boot/compressed/uart-16550.c:44:6: warning: no previous prototype for 'putc'

tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: 27c9d5b3c24af29de643533984f1ba3e650c7c78 commit: 31b2f3dc851c65fee288612432c4fc956f1a264e [9638/12117] MIPS: enable both vmlinux.gz.itb and vmlinuz for generic config: mips-buildonly-randconfig-r003-20220113 (https://download.01.org/0day-ci/archive/20220113/202201131722.d49vrQCm-lk...) compiler: mipsel-linux-gcc (GCC) 11.2.0 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/next/linux-next.git/commi... git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git git fetch --no-tags linux-next master git checkout 31b2f3dc851c65fee288612432c4fc956f1a264e # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=mips SHELL=/bin/bash 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 >>): 44 | void putc(char c) | ^~~~ vim +/putc +44 arch/mips/boot/compressed/uart-16550.c 1b93b3c3e94be2 Wu Zhangjin 2009-10-14 43 1b93b3c3e94be2 Wu Zhangjin 2009-10-14 @44 void putc(char c) :::::: The code at line 44 was first introduced by commit :::::: 1b93b3c3e94be2605759735a89fc935ba5f58dcf MIPS: Add support for GZIP / BZIP2 / LZMA compressed kernel images :::::: TO: Wu Zhangjin <wuzhangjin(a)gmail.com&gt; :::::: CC: Ralf Baechle <ralf(a)linux-mips.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org