tree:   https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git arm64/pgtable/cleanup
head:   198e77ecb00474ffeb2d37614580d6936efa0dbc
commit: 5570396155aab65aeb4f58f43067322e1229d0a1 [14/16] arm64: mm: always map fixmap at page granularity
config: arm64-allyesconfig (attached as .config)
compiler: aarch64-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/mark/linux.git/commit/?id=5570396155aab65aeb4f58f43067322e1229d0a1
        git remote add mark-rutland https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git
        git fetch --no-tags mark-rutland arm64/pgtable/cleanup
        git checkout 5570396155aab65aeb4f58f43067322e1229d0a1
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=arm64 

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/arm64/mm/fixmap.c:49:13: warning: no previous prototype for 'early_fixmap_init_pte' [-Wmissing-prototypes]
      49 | void __init early_fixmap_init_pte(pmd_t *pmdp, unsigned long addr)
         |             ^~~~~~~~~~~~~~~~~~~~~
>> arch/arm64/mm/fixmap.c:60:13: warning: no previous prototype for 'early_fixmap_init_pmd' [-Wmissing-prototypes]
      60 | void __init early_fixmap_init_pmd(pud_t *pudp, unsigned long addr,
         |             ^~~~~~~~~~~~~~~~~~~~~
>> arch/arm64/mm/fixmap.c:77:13: warning: no previous prototype for 'early_fixmap_init_pud' [-Wmissing-prototypes]
      77 | void __init early_fixmap_init_pud(p4d_t *p4dp, unsigned long addr,
         |             ^~~~~~~~~~~~~~~~~~~~~


vim +/early_fixmap_init_pte +49 arch/arm64/mm/fixmap.c

    48	
  > 49	void __init early_fixmap_init_pte(pmd_t *pmdp, unsigned long addr)
    50	{
    51		pmd_t pmd = READ_ONCE(*pmdp);
    52		pte_t *ptep;
    53	
    54		if (pmd_none(pmd)) {
    55			ptep = bm_pte[BM_PTE_IDX(addr)];
    56			__pmd_populate(pmdp, __pa_symbol(ptep), PMD_TYPE_TABLE);
    57		}
    58	}
    59	
  > 60	void __init early_fixmap_init_pmd(pud_t *pudp, unsigned long addr,
    61					  unsigned long end)
    62	{
    63		unsigned long next;
    64		pud_t pud = READ_ONCE(*pudp);
    65		pmd_t *pmdp;
    66	
    67		if (pud_none(pud))
    68			__pud_populate(pudp, __pa_symbol(bm_pmd), PUD_TYPE_TABLE);
    69	
    70		pmdp = pmd_offset_kimg(pudp, addr);
    71		do {
    72			next = pmd_addr_end(addr, end);
    73			early_fixmap_init_pte(pmdp, addr);
    74		} while (pmdp++, addr = next, addr != end);
    75	}
    76	
  > 77	void __init early_fixmap_init_pud(p4d_t *p4dp, unsigned long addr,
    78					  unsigned long end)
    79	{
    80		p4d_t p4d = READ_ONCE(*p4dp);
    81		pud_t *pudp;
    82	
    83		if (CONFIG_PGTABLE_LEVELS > 3 && !p4d_none(p4d) &&
    84			   p4d_page_paddr(p4d) != __pa_symbol(bm_pud)) {
    85			/*
    86			 * We only end up here if the kernel mapping and the fixmap
    87			 * share the top level pgd entry, which should only happen on
    88			 * 16k/4 levels configurations.
    89			 */
    90			BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
    91		}
    92	
    93		if (p4d_none(p4d))
    94			__p4d_populate(p4dp, __pa_symbol(bm_pud), P4D_TYPE_TABLE);
    95	
    96		pudp = pud_offset_kimg(p4dp, addr);
    97		early_fixmap_init_pmd(pudp, addr, end);
    98	}
    99	

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