[ardb:arm64-head-refactor-v4 23/38] arch/arm64/kernel/pi/kaslr_early.c:95:17: error: call to undeclared function '__early_cpu_has_rndr'; ISO C99 and later do not support implicit function declarations

[ardb:arm64-head-refactor-v4 23/38] arch/arm64/kernel/pi/kaslr_early.c:95:17: error: call to undeclared function '__early_cpu_has_rndr'; ISO C99 and later do not support implicit function declarations

[kernel test robot]

tree:   git://git.kernel.org/pub/scm/linux/kernel/git/ardb/linux.git arm64-head-refactor-v4
head:   9e199441095c2a38ba1019e8f782e9fd10876da9
commit: b116ed6cbb1b583ebf32c54fff16e0b3e62fad4f [23/38] arm64: head: relocate kernel only a single time if KASLR is enabled
config: arm64-randconfig-r014-20220428 (https://download.01.org/0day-ci/archive/20220429/202204290528.NFbq0iMb-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project c59473aacce38cd7dd77eebceaf3c98c5707ab3b)
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
        # install arm64 cross compiling tool for clang build
        # apt-get install binutils-aarch64-linux-gnu
        # https://git.kernel.org/pub/scm/linux/kernel/git/ardb/linux.git/commit/?id=b116ed6cbb1b583ebf32c54fff16e0b3e62fad4f
        git remote add ardb git://git.kernel.org/pub/scm/linux/kernel/git/ardb/linux.git
        git fetch --no-tags ardb arm64-head-refactor-v4
        git checkout b116ed6cbb1b583ebf32c54fff16e0b3e62fad4f
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm64 SHELL=/bin/bash

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

All errors (new ones prefixed by >>):

>> arch/arm64/kernel/pi/kaslr_early.c:95:17: error: call to undeclared function '__early_cpu_has_rndr'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
           if (!seed && (!__early_cpu_has_rndr() ||
                          ^
>> arch/arm64/kernel/pi/kaslr_early.c:96:10: error: call to undeclared function '__arm64_rndr'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
                         !__arm64_rndr((unsigned long *)&seed)))
                          ^
   arch/arm64/kernel/pi/kaslr_early.c:87:16: warning: no previous prototype for function 'kaslr_early_init' [-Wmissing-prototypes]
   asmlinkage u64 kaslr_early_init(const void *fdt)
                  ^
   arch/arm64/kernel/pi/kaslr_early.c:87:12: note: declare 'static' if the function is not intended to be used outside of this translation unit
   asmlinkage u64 kaslr_early_init(const void *fdt)
              ^
              static 
   1 warning and 2 errors generated.


vim +/__early_cpu_has_rndr +95 arch/arm64/kernel/pi/kaslr_early.c

    86	
    87	asmlinkage u64 kaslr_early_init(const void *fdt)
    88	{
    89		u64 seed, mask, offset;
    90	
    91		if (is_kaslr_disabled_cmdline(fdt))
    92			return 0;
    93	
    94		seed = get_kaslr_seed(fdt);
  > 95		if (!seed && (!__early_cpu_has_rndr() ||
  > 96			      !__arm64_rndr((unsigned long *)&seed)))
    97			return 0;
    98	
    99		/*
   100		 * OK, so we are proceeding with KASLR enabled. Calculate a suitable
   101		 * kernel image offset from the seed. Let's place the kernel in the
   102		 * middle half of the VMALLOC area (VA_BITS_MIN - 2), and stay clear of
   103		 * the lower and upper quarters to avoid colliding with other
   104		 * allocations.
   105		 * Even if we could randomize at page granularity for 16k and 64k pages,
   106		 * let's always round to 2 MB so we don't interfere with the ability to
   107		 * map using contiguous PTEs
   108		 */
   109		mask = ((1UL << (VA_BITS_MIN - 2)) - 1) & ~(SZ_2M - 1);
   110		offset = BIT(VA_BITS_MIN - 3) + (seed & mask);
   111	
   112		if (!IS_ENABLED(CONFIG_KASAN_VMALLOC) &&
   113		    (IS_ENABLED(CONFIG_KASAN_GENERIC) ||
   114		     IS_ENABLED(CONFIG_KASAN_SW_TAGS)))
   115			/*
   116			 * KASAN without KASAN_VMALLOC does not expect the module region
   117			 * to intersect the vmalloc region, since shadow memory is
   118			 * allocated for each module at load time, whereas the vmalloc
   119			 * region is shadowed by KASAN zero pages. So keep modules
   120			 * out of the vmalloc region if KASAN is enabled without
   121			 * KASAN_VMALLOC, and put the kernel well within 4 GB of the
   122			 * module region.
   123			 */
   124			return offset % SZ_2G;
   125	
   126		return offset;
   127	}
   128	

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