Re: [RFC V1 PATCH mm-hotfixes 2/3] x86/mm: define p*d_populate_kernel() and top-level page table sync

[kernel test robot <lkp@intel.com>]

Hi Harry,

[This is a private test report for your RFC patch.]
kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/Harry-Yoo/mm-introduce-and-use-pgd-p4d-_populate_kernel/20250709-211850
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20250709131657.5660-3-harry.yoo%40oracle.com
patch subject: [RFC V1 PATCH mm-hotfixes 2/3] x86/mm: define p*d_populate_kernel() and top-level page table sync
config: i386-buildonly-randconfig-001-20250710 (https://download.01.org/0day-ci/archive/20250710/202507101530.PwamBJGe-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14+deb12u1) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250710/202507101530.PwamBJGe-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202507101530.PwamBJGe-lkp@intel.com/

All errors (new ones prefixed by >>):

   mm/percpu.c: In function 'pcpu_populate_pte':
>> mm/percpu.c:3137:17: error: implicit declaration of function 'pgd_populate_kernel'; did you mean 'pmd_populate_kernel'? [-Werror=implicit-function-declaration]
    3137 |                 pgd_populate_kernel(addr, pgd, p4d);
         |                 ^~~~~~~~~~~~~~~~~~~
         |                 pmd_populate_kernel
>> mm/percpu.c:3143:17: error: implicit declaration of function 'p4d_populate_kernel'; did you mean 'pmd_populate_kernel'? [-Werror=implicit-function-declaration]
    3143 |                 p4d_populate_kernel(addr, p4d, pud);
         |                 ^~~~~~~~~~~~~~~~~~~
         |                 pmd_populate_kernel
   cc1: some warnings being treated as errors


vim +3137 mm/percpu.c

20c035764626c5 Kefeng Wang 2022-01-19  3124  
20c035764626c5 Kefeng Wang 2022-01-19  3125  #ifndef PTE_TABLE_SIZE
20c035764626c5 Kefeng Wang 2022-01-19  3126  #define PTE_TABLE_SIZE PAGE_SIZE
20c035764626c5 Kefeng Wang 2022-01-19  3127  #endif
20c035764626c5 Kefeng Wang 2022-01-19  3128  void __init __weak pcpu_populate_pte(unsigned long addr)
20c035764626c5 Kefeng Wang 2022-01-19  3129  {
20c035764626c5 Kefeng Wang 2022-01-19  3130  	pgd_t *pgd = pgd_offset_k(addr);
20c035764626c5 Kefeng Wang 2022-01-19  3131  	p4d_t *p4d;
20c035764626c5 Kefeng Wang 2022-01-19  3132  	pud_t *pud;
20c035764626c5 Kefeng Wang 2022-01-19  3133  	pmd_t *pmd;
20c035764626c5 Kefeng Wang 2022-01-19  3134  
20c035764626c5 Kefeng Wang 2022-01-19  3135  	if (pgd_none(*pgd)) {
c6f239796b55db Guo Weikang 2025-01-02  3136  		p4d = memblock_alloc_or_panic(P4D_TABLE_SIZE, P4D_TABLE_SIZE);
eb1f92deca7a01 Harry Yoo   2025-07-09 @3137  		pgd_populate_kernel(addr, pgd, p4d);
20c035764626c5 Kefeng Wang 2022-01-19  3138  	}
20c035764626c5 Kefeng Wang 2022-01-19  3139  
20c035764626c5 Kefeng Wang 2022-01-19  3140  	p4d = p4d_offset(pgd, addr);
20c035764626c5 Kefeng Wang 2022-01-19  3141  	if (p4d_none(*p4d)) {
c6f239796b55db Guo Weikang 2025-01-02  3142  		pud = memblock_alloc_or_panic(PUD_TABLE_SIZE, PUD_TABLE_SIZE);
eb1f92deca7a01 Harry Yoo   2025-07-09 @3143  		p4d_populate_kernel(addr, p4d, pud);
20c035764626c5 Kefeng Wang 2022-01-19  3144  	}
20c035764626c5 Kefeng Wang 2022-01-19  3145  
20c035764626c5 Kefeng Wang 2022-01-19  3146  	pud = pud_offset(p4d, addr);
20c035764626c5 Kefeng Wang 2022-01-19  3147  	if (pud_none(*pud)) {
c6f239796b55db Guo Weikang 2025-01-02  3148  		pmd = memblock_alloc_or_panic(PMD_TABLE_SIZE, PMD_TABLE_SIZE);
41fd59b7f9bdde Bibo Mao    2023-07-12  3149  		pud_populate(&init_mm, pud, pmd);
20c035764626c5 Kefeng Wang 2022-01-19  3150  	}
20c035764626c5 Kefeng Wang 2022-01-19  3151  
20c035764626c5 Kefeng Wang 2022-01-19  3152  	pmd = pmd_offset(pud, addr);
20c035764626c5 Kefeng Wang 2022-01-19  3153  	if (!pmd_present(*pmd)) {
20c035764626c5 Kefeng Wang 2022-01-19  3154  		pte_t *new;
20c035764626c5 Kefeng Wang 2022-01-19  3155  
c6f239796b55db Guo Weikang 2025-01-02  3156  		new = memblock_alloc_or_panic(PTE_TABLE_SIZE, PTE_TABLE_SIZE);
20c035764626c5 Kefeng Wang 2022-01-19  3157  		pmd_populate_kernel(&init_mm, pmd, new);
20c035764626c5 Kefeng Wang 2022-01-19  3158  	}
20c035764626c5 Kefeng Wang 2022-01-19  3159  
20c035764626c5 Kefeng Wang 2022-01-19  3160  	return;
20c035764626c5 Kefeng Wang 2022-01-19  3161  }
20c035764626c5 Kefeng Wang 2022-01-19  3162  

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