[mingo-tip:sched/headers 1880/2372] arch/x86/entry/vdso/vdso32-setup.c:55:12: warning: no previous prototype for 'sysenter_setup'

[kernel test robot]

tree:   git://git.kernel.org/pub/scm/linux/kernel/git/mingo/tip.git sched/headers
head:   67f8f45b4d0cf00f8e53fc1c2b50c67608ede063
commit: f4fe8ddb47d3a44bc202157766c5c2ef631785a2 [1880/2372] headers/deps: x86/elf: Optimize <asm/elf.h> dependencies, split out <asm/elf_api.h>
config: i386-tinyconfig (https://download.01.org/0day-ci/archive/20220108/202201081616.RgCtvCvQ-lkp@xxxxxxxxx/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/mingo/tip.git/commit/?id=f4fe8ddb47d3a44bc202157766c5c2ef631785a2
        git remote add mingo-tip git://git.kernel.org/pub/scm/linux/kernel/git/mingo/tip.git
        git fetch --no-tags mingo-tip sched/headers
        git checkout f4fe8ddb47d3a44bc202157766c5c2ef631785a2
        # save the config file to linux build tree
        mkdir build_dir
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash arch/x86/entry/vdso/ kernel/

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

All warnings (new ones prefixed by >>):

>> arch/x86/entry/vdso/vdso32-setup.c:55:12: warning: no previous prototype for 'sysenter_setup' [-Wmissing-prototypes]
      55 | int __init sysenter_setup(void)
         |            ^~~~~~~~~~~~~~


vim +/sysenter_setup +55 arch/x86/entry/vdso/vdso32-setup.c

^1da177e4c3f41 arch/i386/kernel/sysenter.c        Linus Torvalds      2005-04-16  54  
a6c4e076ee4c1e arch/i386/kernel/sysenter.c        Jeremy Fitzhardinge 2007-05-02 @55  int __init sysenter_setup(void)
^1da177e4c3f41 arch/i386/kernel/sysenter.c        Linus Torvalds      2005-04-16  56  {
0a6d1fa0d2b48f arch/x86/entry/vdso/vdso32-setup.c Andy Lutomirski     2015-10-05  57  	init_vdso_image(&vdso_image_32);
^1da177e4c3f41 arch/i386/kernel/sysenter.c        Linus Torvalds      2005-04-16  58  
^1da177e4c3f41 arch/i386/kernel/sysenter.c        Linus Torvalds      2005-04-16  59  	return 0;
^1da177e4c3f41 arch/i386/kernel/sysenter.c        Linus Torvalds      2005-04-16  60  }
e6e5494cb23d19 arch/i386/kernel/sysenter.c        Ingo Molnar         2006-06-27  61  

:::::: The code at line 55 was first introduced by commit
:::::: a6c4e076ee4c1ea670e4faa55814e63dd08e3f29 [PATCH] i386: clean up identify_cpu

:::::: TO: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
:::::: CC: Andi Kleen <andi@xxxxxxxxxxxxxxxxx>

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