tree:   https://git.kernel.org/pub/scm/linux/kernel/git/joro/linux.git sev-es-kexec
head:   3467dc3cdbe65c619cd9b5c8db47da63b0655300
commit: 4eeabbfae0a6163e935a6462acc02fe4f17d3680 [1/12] kexec: Allow architecture code to opt-out at runtime
config: m68k-randconfig-r035-20210702 (attached as .config)
compiler: m68k-linux-gcc (GCC) 9.3.0
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/joro/linux.git/commit/?id=4eeabbfae0a6163e935a6462acc02fe4f17d3680
        git remote add joro https://git.kernel.org/pub/scm/linux/kernel/git/joro/linux.git
        git fetch --no-tags joro sev-es-kexec
        git checkout 4eeabbfae0a6163e935a6462acc02fe4f17d3680
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=m68k 

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 >>):

>> kernel/kexec.c:198:13: warning: no previous prototype for 'arch_kexec_supported' [-Wmissing-prototypes]
     198 | bool __weak arch_kexec_supported(void)
         |             ^~~~~~~~~~~~~~~~~~~~

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for ATARI_KBD_CORE
   Depends on !UML && INPUT && INPUT_KEYBOARD
   Selected by
   - MOUSE_ATARI && !UML && INPUT && INPUT_MOUSE && ATARI


vim +/arch_kexec_supported +198 kernel/kexec.c

   176	
   177	/*
   178	 * Exec Kernel system call: for obvious reasons only root may call it.
   179	 *
   180	 * This call breaks up into three pieces.
   181	 * - A generic part which loads the new kernel from the current
   182	 *   address space, and very carefully places the data in the
   183	 *   allocated pages.
   184	 *
   185	 * - A generic part that interacts with the kernel and tells all of
   186	 *   the devices to shut down.  Preventing on-going dmas, and placing
   187	 *   the devices in a consistent state so a later kernel can
   188	 *   reinitialize them.
   189	 *
   190	 * - A machine specific part that includes the syscall number
   191	 *   and then copies the image to it's final destination.  And
   192	 *   jumps into the image at entry.
   193	 *
   194	 * kexec does not sync, or unmount filesystems so if you need
   195	 * that to happen you need to do that yourself.
   196	 */
   197	
 > 198	bool __weak arch_kexec_supported(void)
   199	{
   200		return true;
   201	}
   202	

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