#include <linux/mm.h> #include <linux/highmem.h> #include <linux/sched.h> #include <linux/hugetlb.h> static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, struct mm_walk *walk) { pte_t *pte; int err = 0; pte = pte_offset_map(pmd, addr); for (;;) { err = walk->pte_entry(pte, addr, addr + PAGE_SIZE, walk); if (err) break; addr += PAGE_SIZE; if (addr == end) break; pte++; } pte_unmap(pte); return err; } static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end, struct mm_walk *walk) { pmd_t *pmd; unsigned long next; int err = 0; pmd = pmd_offset(pud, addr); do { again: next = pmd_addr_end(addr, end); if (pmd_none(*pmd)) { if (walk->pte_hole) err = walk->pte_hole(addr, next, walk); if (err) break; continue; } /* * This implies that each ->pmd_entry() handler * needs to know about pmd_trans_huge() pmds */ if (walk->pmd_entry) err = walk->pmd_entry(pmd, addr, next, walk); if (err) break; /* * Check this here so we only break down trans_huge * pages when we _need_ to */ if (!walk->pte_entry) continue; split_huge_page_pmd_mm(walk->mm, addr, pmd); if (pmd_none_or_trans_huge_or_clear_bad(pmd)) goto again; err = walk_pte_range(pmd, addr, next, walk); if (err) break; } while (pmd++, addr = next, addr != end); return err; } static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end, struct mm_walk *walk) { pud_t *pud; unsigned long next; int err = 0; pud = pud_offset(pgd, addr); do { next = pud_addr_end(addr, end); if (pud_none_or_clear_bad(pud)) { if (walk->pte_hole) err = walk->pte_hole(addr, next, walk); if (err) break; continue; } if (walk->pud_entry) err = walk->pud_entry(pud, addr, next, walk); if (!err && (walk->pmd_entry || walk->pte_entry)) err = walk_pmd_range(pud, addr, next, walk); if (err) break; } while (pud++, addr = next, addr != end); return err; } #ifdef CONFIG_HUGETLB_PAGE static unsigned long hugetlb_entry_end(struct hstate *h, unsigned long addr, unsigned long end) { unsigned long boundary = (addr & huge_page_mask(h)) + huge_page_size(h); return boundary < end ? boundary : end; } static int walk_hugetlb_range(struct vm_area_struct *vma, unsigned long addr, unsigned long end, struct mm_walk *walk) { struct hstate *h = hstate_vma(vma); unsigned long next; unsigned long hmask = huge_page_mask(h); pte_t *pte; int err = 0; do { next = hugetlb_entry_end(h, addr, end); pte = huge_pte_offset(walk->mm, addr & hmask); if (pte && walk->hugetlb_entry) err = walk->hugetlb_entry(pte, hmask, addr, next, walk); if (err) return err; } while (addr = next, addr != end); return 0; } #else /* CONFIG_HUGETLB_PAGE */ static int walk_hugetlb_range(struct vm_area_struct *vma, unsigned long addr, unsigned long end, struct mm_walk *walk) { return 0; } #endif /* CONFIG_HUGETLB_PAGE */ /** * walk_page_range - walk a memory map's page tables with a callback * @addr: starting address * @end: ending address * @walk: set of callbacks to invoke for each level of the tree * * Recursively walk the page table for the memory area in a VMA, * calling supplied callbacks. Callbacks are called in-order (first * PGD, first PUD, first PMD, first PTE, second PTE... second PMD, * etc.). If lower-level callbacks are omitted, walking depth is reduced. * * Each callback receives an entry pointer and the start and end of the * associated range, and a copy of the original mm_walk for access to * the ->private or ->mm fields. * * Usually no locks are taken, but splitting transparent huge page may * take page table lock. And the bottom level iterator will map PTE * directories from highmem if necessary. * * If any callback returns a non-zero value, the walk is aborted and * the return value is propagated back to the caller. Otherwise 0 is returned. * * walk->mm->mmap_sem must be held for at least read if walk->hugetlb_entry * is !NULL. */ int walk_page_range(unsigned long addr, unsigned long end, struct mm_walk *walk) { pgd_t *pgd; unsigned long next; int err = 0; if (addr >= end) return err; if (!walk->mm) return -EINVAL; VM_BUG_ON(!rwsem_is_locked(&walk->mm->mmap_sem)); pgd = pgd_offset(walk->mm, addr); do { struct vm_area_struct *vma = NULL; next = pgd_addr_end(addr, end); /* * This function was not intended to be vma based. * But there are vma special cases to be handled: * - hugetlb vma's * - VM_PFNMAP vma's */ vma = find_vma(walk->mm, addr); if (vma) { /* * There are no page structures backing a VM_PFNMAP * range, so do not allow split_huge_page_pmd(). */ if ((vma->vm_start <= addr) && (vma->vm_flags & VM_PFNMAP)) { next = vma->vm_end; pgd = pgd_offset(walk->mm, next); continue; } /* * Handle hugetlb vma individually because pagetable * walk for the hugetlb page is dependent on the * architecture and we can't handled it in the same * manner as non-huge pages. */ if (walk->hugetlb_entry && (vma->vm_start <= addr) && is_vm_hugetlb_page(vma)) { if (vma->vm_end < next) next = vma->vm_end; /* * Hugepage is very tightly coupled with vma, * so walk through hugetlb entries within a * given vma. */ err = walk_hugetlb_range(vma, addr, next, walk); if (err) break; pgd = pgd_offset(walk->mm, next); continue; } } if (pgd_none_or_clear_bad(pgd)) { if (walk->pte_hole) err = walk->pte_hole(addr, next, walk); if (err) break; pgd++; continue; } if (walk->pgd_entry) err = walk->pgd_entry(pgd, addr, next, walk); if (!err && (walk->pud_entry || walk->pmd_entry || walk->pte_entry)) err = walk_pud_range(pgd, addr, next, walk); if (err) break; pgd++; } while (addr = next, addr < end); return err; }