arch/powerpc/platforms/microwatt/rng.c:17:5: error: no previous prototype for 'microwatt_get_random_darn'

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   debe436e77c72fcee804fb867f275e6d31aa999c
commit: c25769fddaec13509b6cdc7ad17458f239c4cee7 powerpc/microwatt: Add support for hardware random number generator
date:   5 months ago
config: powerpc64-buildonly-randconfig-r002-20210929 (attached as .config)
compiler: powerpc64le-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=c25769fddaec13509b6cdc7ad17458f239c4cee7
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout c25769fddaec13509b6cdc7ad17458f239c4cee7
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=powerpc 

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

All errors (new ones prefixed by >>):

>> arch/powerpc/platforms/microwatt/rng.c:17:5: error: no previous prototype for 'microwatt_get_random_darn' [-Werror=missing-prototypes]
      17 | int microwatt_get_random_darn(unsigned long *v)
         |     ^~~~~~~~~~~~~~~~~~~~~~~~~
   cc1: all warnings being treated as errors


vim +/microwatt_get_random_darn +17 arch/powerpc/platforms/microwatt/rng.c

    16	
  > 17	int microwatt_get_random_darn(unsigned long *v)
    18	{
    19		unsigned long val;
    20	
    21		/* Using DARN with L=1 - 64-bit conditioned random number */
    22		asm volatile(PPC_DARN(%0, 1) : "=r"(val));
    23	
    24		if (val == DARN_ERR)
    25			return 0;
    26	
    27		*v = val;
    28	
    29		return 1;
    30	}
    31	

---
0-DAY CI Kernel Test Service, Intel Corporation
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Attachment: .config.gz
Description: application/gzip