Hi Geert,

FYI, the error/warning still remains.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   dfa377c35d70c31139b1274ec49f87d380996c42
commit: 0673cb38951215060d7993b43ad3c45cd413c2c3 ARM: 9045/1: uncompress: Validate start of physical memory against passed DTB
date:   6 months ago
config: arm-randconfig-r003-20210814 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 62df4df41c939205b2dc0a2a3bfb75b8c1ed74fa)
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=0673cb38951215060d7993b43ad3c45cd413c2c3
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout 0673cb38951215060d7993b43ad3c45cd413c2c3
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm 

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 >>):

>> arch/arm/boot/compressed/fdt_check_mem_start.c:62:10: warning: no previous prototype for function 'fdt_check_mem_start' [-Wmissing-prototypes]
   uint32_t fdt_check_mem_start(uint32_t mem_start, const void *fdt)
            ^
   arch/arm/boot/compressed/fdt_check_mem_start.c:62:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   uint32_t fdt_check_mem_start(uint32_t mem_start, const void *fdt)
   ^
   static 
   1 warning generated.


vim +/fdt_check_mem_start +62 arch/arm/boot/compressed/fdt_check_mem_start.c

    46	
    47	/*
    48	 * Check the start of physical memory
    49	 *
    50	 * Traditionally, the start address of physical memory is obtained by masking
    51	 * the program counter.  However, this does require that this address is a
    52	 * multiple of 128 MiB, precluding booting Linux on platforms where this
    53	 * requirement is not fulfilled.
    54	 * Hence validate the calculated address against the memory information in the
    55	 * DTB, and, if out-of-range, replace it by the real start address.
    56	 * To preserve backwards compatibility (systems reserving a block of memory
    57	 * at the start of physical memory, kdump, ...), the traditional method is
    58	 * always used if it yields a valid address.
    59	 *
    60	 * Return value: start address of physical memory to use
    61	 */
  > 62	uint32_t fdt_check_mem_start(uint32_t mem_start, const void *fdt)

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