[kbuild-all] [linux-next:master 2551/10701] arch/x86/mm/init.c:79:22: warning: no previous prototype for function 'pgprot2cachemode'

tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: fb57b1fabcb28f358901b2df90abd2b48abc1ca8 commit: 7fa3e10f0f3646108a1018004d0f571c3222dc9f [2551/10701] x86/mm: Move pgprot2cachemode out of line config: x86_64-randconfig-r012-20200519 (attached as .config) compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project 135b877874fae96b4372c8a3fbfaa8ff44ff86e3) reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu git checkout 7fa3e10f0f3646108a1018004d0f571c3222dc9f # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kbuild test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>, old ones prefixed by <<): arch/x86/mm/init.c:74:6: warning: no previous prototype for function 'x86_has_pat_wp' [-Wmissing-prototypes] bool x86_has_pat_wp(void) ^ arch/x86/mm/init.c:74:1: note: declare 'static' if the function is not intended to be used outside of this translation unit bool x86_has_pat_wp(void) ^ static enum page_cache_mode pgprot2cachemode(pgprot_t pgprot) ^ arch/x86/mm/init.c:79:1: note: declare 'static' if the function is not intended to be used outside of this translation unit enum page_cache_mode pgprot2cachemode(pgprot_t pgprot) ^ static arch/x86/mm/init.c:875:13: warning: no previous prototype for function 'mem_encrypt_free_decrypted_mem' [-Wmissing-prototypes] void __weak mem_encrypt_free_decrypted_mem(void) { } ^ arch/x86/mm/init.c:875:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __weak mem_encrypt_free_decrypted_mem(void) { } ^ static 3 warnings generated. vim +/pgprot2cachemode +79 arch/x86/mm/init.c 72 73 /* Check that the write-protect PAT entry is set for write-protect */ 75 { 76 return __pte2cachemode_tbl[_PAGE_CACHE_MODE_WP] == _PAGE_CACHE_MODE_WP; 77 } 78 80 { 81 unsigned long masked; 82 83 masked = pgprot_val(pgprot) & _PAGE_CACHE_MASK; 84 if (likely(masked == 0)) 85 return 0; 86 return __pte2cachemode_tbl[__pte2cm_idx(masked)]; 87 } 88 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org