[tip:x86/entry 4/80] drivers/xen/events/events_base.c:1664:6: warning: no previous prototype for 'xen_setup_callback_vector'

[kbuild test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/entry
head:   095b7a3e7745e6fb7cf0a1c09967c4f43e76f8f4
commit: fad1940a6a856f59b073e8650e02052ce531154c [4/80] x86/xen: Split HVM vector callback setup and interrupt gate allocation
config: arm-randconfig-r013-20200519 (attached as .config)
compiler: arm-linux-gnueabi-gcc (GCC) 9.3.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        git checkout fad1940a6a856f59b073e8650e02052ce531154c
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arm 

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

All warnings (new ones prefixed by >>, old ones prefixed by <<):

>> drivers/xen/events/events_base.c:1664:6: warning: no previous prototype for 'xen_setup_callback_vector' [-Wmissing-prototypes]
1664 | void xen_setup_callback_vector(void) {}
|      ^~~~~~~~~~~~~~~~~~~~~~~~~

vim +/xen_setup_callback_vector +1664 drivers/xen/events/events_base.c

  1654	
  1655	static __init void xen_alloc_callback_vector(void)
  1656	{
  1657		if (!xen_have_vector_callback)
  1658			return;
  1659	
  1660		pr_info("Xen HVM callback vector for event delivery is enabled\n");
  1661		alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, xen_hvm_callback_vector);
  1662	}
  1663	#else
> 1664	void xen_setup_callback_vector(void) {}
  1665	static inline void xen_alloc_callback_vector(void) {}
  1666	#endif
  1667	

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

Attachment: .config.gz
Description: application/gzip