arch/mips/boot/compressed/dbg.c:12:13: warning: no previous prototype for 'putc'

[kernel test robot <lkp@intel.com>]

Hi YunQiang,

First bad commit (maybe != root cause):

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   59f0c2447e2553b0918b4a9fd38763a5c0587d02
commit: 31b2f3dc851c65fee288612432c4fc956f1a264e MIPS: enable both vmlinux.gz.itb and vmlinuz for generic
date:   4 months ago
config: mips-allmodconfig (https://download.01.org/0day-ci/archive/20220422/202204220803.gjpqZj5l-lkp@intel.com/config)
compiler: mips-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/torvalds/linux.git/commit/?id=31b2f3dc851c65fee288612432c4fc956f1a264e
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout 31b2f3dc851c65fee288612432c4fc956f1a264e
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross W=1 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@intel.com>

All warnings (new ones prefixed by >>):

>> arch/mips/boot/compressed/dbg.c:12:13: warning: no previous prototype for 'putc' [-Wmissing-prototypes]
      12 | void __weak putc(char c)
         |             ^~~~
>> arch/mips/boot/compressed/dbg.c:16:6: warning: no previous prototype for 'puts' [-Wmissing-prototypes]
      16 | void puts(const char *s)
         |      ^~~~
>> arch/mips/boot/compressed/dbg.c:26:6: warning: no previous prototype for 'puthex' [-Wmissing-prototypes]
      26 | void puthex(unsigned long long val)
         |      ^~~~~~


vim +/putc +12 arch/mips/boot/compressed/dbg.c

1b93b3c3e94be2 Wu Zhangjin 2009-10-14  11  
e52dd9fc6b9e0c Wu Zhangjin 2010-01-26 @12  void __weak putc(char c)
1b93b3c3e94be2 Wu Zhangjin 2009-10-14  13  {
1b93b3c3e94be2 Wu Zhangjin 2009-10-14  14  }
1b93b3c3e94be2 Wu Zhangjin 2009-10-14  15  
1b93b3c3e94be2 Wu Zhangjin 2009-10-14 @16  void puts(const char *s)
1b93b3c3e94be2 Wu Zhangjin 2009-10-14  17  {
1b93b3c3e94be2 Wu Zhangjin 2009-10-14  18  	char c;
1b93b3c3e94be2 Wu Zhangjin 2009-10-14  19  	while ((c = *s++) != '\0') {
1b93b3c3e94be2 Wu Zhangjin 2009-10-14  20  		putc(c);
1b93b3c3e94be2 Wu Zhangjin 2009-10-14  21  		if (c == '\n')
1b93b3c3e94be2 Wu Zhangjin 2009-10-14  22  			putc('\r');
1b93b3c3e94be2 Wu Zhangjin 2009-10-14  23  	}
1b93b3c3e94be2 Wu Zhangjin 2009-10-14  24  }
1b93b3c3e94be2 Wu Zhangjin 2009-10-14  25  
1b93b3c3e94be2 Wu Zhangjin 2009-10-14 @26  void puthex(unsigned long long val)

:::::: The code at line 12 was first introduced by commit
:::::: e52dd9fc6b9e0c17b220bd38371ff15032a1a155 MIPS: Simplify the weak annotation with __weak

:::::: TO: Wu Zhangjin <wuzhangjin@gmail.com>
:::::: CC: Ralf Baechle <ralf@linux-mips.org>

-- 
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https://01.org/lkp