tree: https://gitee.com/openeuler/kernel.git OLK-6.6 head: a7f4bf73c34996ee6cdda292e8f906a9c30879de commit: eb6d298e49a22a61e4a25377329a81445bed4611 [2380/2380] mm/pagewalk: introduce folio_walk_start() + folio_walk_end() config: arm64-randconfig-003-20250609 (https://download.01.org/0day-ci/archive/20250610/202506100341.pGF5A7BE-lkp@i...) compiler: aarch64-linux-gcc (GCC) 14.3.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250610/202506100341.pGF5A7BE-lkp@i...) 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/202506100341.pGF5A7BE-lkp@intel.com/ All errors (new ones prefixed by >>): aarch64-linux-ld: mm/pagewalk.o: in function `folio_walk_start':

...

mm/pagewalk.c:816:(.text+0x1cbc): undefined reference to `vm_normal_page_pmd' mm/pagewalk.c:816:(.text+0x1cbc): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `vm_normal_page_pmd' aarch64-linux-ld: mm/kasan/shadow.o: in function `memcpy_mc': shadow.c:(.text+0x7ac): undefined reference to `__memcpy_mc' shadow.c:(.text+0x7ac): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `__memcpy_mc'

vim +816 mm/pagewalk.c 682 683 /** 684 * folio_walk_start - walk the page tables to a folio 685 * @fw: filled with information on success. 686 * @vma: the VMA. 687 * @addr: the virtual address to use for the page table walk. 688 * @flags: flags modifying which folios to walk to. 689 * 690 * Walk the page tables using @addr in a given @vma to a mapped folio and 691 * return the folio, making sure that the page table entry referenced by 692 * @addr cannot change until folio_walk_end() was called. 693 * 694 * As default, this function returns only folios that are not special (e.g., not 695 * the zeropage) and never returns folios that are supposed to be ignored by the 696 * VM as documented by vm_normal_page(). If requested, zeropages will be 697 * returned as well. 698 * 699 * As default, this function only considers present page table entries. 700 * If requested, it will also consider migration entries. 701 * 702 * If this function returns NULL it might either indicate "there is nothing" or 703 * "there is nothing suitable". 704 * 705 * On success, @fw is filled and the function returns the folio while the PTL 706 * is still held and folio_walk_end() must be called to clean up, 707 * releasing any held locks. The returned folio must *not* be used after the 708 * call to folio_walk_end(), unless a short-term folio reference is taken before 709 * that call. 710 * 711 * @fw->page will correspond to the page that is effectively referenced by 712 * @addr. However, for migration entries and shared zeropages @fw->page is 713 * set to NULL. Note that large folios might be mapped by multiple page table 714 * entries, and this function will always only lookup a single entry as 715 * specified by @addr, which might or might not cover more than a single page of 716 * the returned folio. 717 * 718 * This function must *not* be used as a naive replacement for 719 * get_user_pages() / pin_user_pages(), especially not to perform DMA or 720 * to carelessly modify page content. This function may *only* be used to grab 721 * short-term folio references, never to grab long-term folio references. 722 * 723 * Using the page table entry pointers in @fw for reading or modifying the 724 * entry should be avoided where possible: however, there might be valid 725 * use cases. 726 * 727 * WARNING: Modifying page table entries in hugetlb VMAs requires a lot of care. 728 * For example, PMD page table sharing might require prior unsharing. Also, 729 * logical hugetlb entries might span multiple physical page table entries, 730 * which *must* be modified in a single operation (set_huge_pte_at(), 731 * huge_ptep_set_*, ...). Note that the page table entry stored in @fw might 732 * not correspond to the first physical entry of a logical hugetlb entry. 733 * 734 * The mmap lock must be held in read mode. 735 * 736 * Return: folio pointer on success, otherwise NULL. 737 */ 738 struct folio *folio_walk_start(struct folio_walk *fw, 739 struct vm_area_struct *vma, unsigned long addr, 740 folio_walk_flags_t flags) 741 { 742 unsigned long entry_size; 743 bool expose_page = true; 744 struct page *page; 745 pud_t *pudp, pud; 746 pmd_t *pmdp, pmd; 747 pte_t *ptep, pte; 748 spinlock_t *ptl; 749 pgd_t *pgdp; 750 p4d_t *p4dp; 751 752 mmap_assert_locked(vma->vm_mm); 753 vma_pgtable_walk_begin(vma); 754 755 if (WARN_ON_ONCE(addr < vma->vm_start || addr >= vma->vm_end)) 756 goto not_found; 757 758 pgdp = pgd_offset(vma->vm_mm, addr); 759 if (pgd_none_or_clear_bad(pgdp)) 760 goto not_found; 761 762 p4dp = p4d_offset(pgdp, addr); 763 if (p4d_none_or_clear_bad(p4dp)) 764 goto not_found; 765 766 pudp = pud_offset(p4dp, addr); 767 pud = pudp_get(pudp); 768 if (pud_none(pud)) 769 goto not_found; 770 if (IS_ENABLED(CONFIG_PGTABLE_HAS_HUGE_LEAVES) && pud_leaf(pud)) { 771 ptl = pud_lock(vma->vm_mm, pudp); 772 pud = pudp_get(pudp); 773 774 entry_size = PUD_SIZE; 775 fw->level = FW_LEVEL_PUD; 776 fw->pudp = pudp; 777 fw->pud = pud; 778 779 if (!pud_present(pud) || pud_devmap(pud)) { 780 spin_unlock(ptl); 781 goto not_found; 782 } else if (!pud_leaf(pud)) { 783 spin_unlock(ptl); 784 goto pmd_table; 785 } 786 /* 787 * TODO: vm_normal_page_pud() will be handy once we want to 788 * support PUD mappings in VM_PFNMAP|VM_MIXEDMAP VMAs. 789 */ 790 page = pud_page(pud); 791 goto found; 792 } 793 794 pmd_table: 795 VM_WARN_ON_ONCE(pud_leaf(*pudp)); 796 pmdp = pmd_offset(pudp, addr); 797 pmd = pmdp_get_lockless(pmdp); 798 if (pmd_none(pmd)) 799 goto not_found; 800 if (IS_ENABLED(CONFIG_PGTABLE_HAS_HUGE_LEAVES) && pmd_leaf(pmd)) { 801 ptl = pmd_lock(vma->vm_mm, pmdp); 802 pmd = pmdp_get(pmdp); 803 804 entry_size = PMD_SIZE; 805 fw->level = FW_LEVEL_PMD; 806 fw->pmdp = pmdp; 807 fw->pmd = pmd; 808 809 if (pmd_none(pmd)) { 810 spin_unlock(ptl); 811 goto not_found; 812 } else if (!pmd_leaf(pmd)) { 813 spin_unlock(ptl); 814 goto pte_table; 815 } else if (pmd_present(pmd)) {

816 page = vm_normal_page_pmd(vma, addr, pmd);

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