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Diffstat (limited to 'include/linux/pagewalk.h')
| -rw-r--r-- | include/linux/pagewalk.h | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/include/linux/pagewalk.h b/include/linux/pagewalk.h new file mode 100644 index 000000000..f3fafb731 --- /dev/null +++ b/include/linux/pagewalk.h @@ -0,0 +1,108 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_PAGEWALK_H +#define _LINUX_PAGEWALK_H + +#include <linux/mm.h> + +struct mm_walk; + +/** + * struct mm_walk_ops - callbacks for walk_page_range + * @pgd_entry: if set, called for each non-empty PGD (top-level) entry + * @p4d_entry: if set, called for each non-empty P4D entry + * @pud_entry: if set, called for each non-empty PUD entry + * @pmd_entry: if set, called for each non-empty PMD entry + * this handler is required to be able to handle + * pmd_trans_huge() pmds. They may simply choose to + * split_huge_page() instead of handling it explicitly. + * @pte_entry: if set, called for each PTE (lowest-level) entry, + * including empty ones + * @pte_hole: if set, called for each hole at all levels, + * depth is -1 if not known, 0:PGD, 1:P4D, 2:PUD, 3:PMD. + * Any folded depths (where PTRS_PER_P?D is equal to 1) + * are skipped. + * @hugetlb_entry: if set, called for each hugetlb entry + * @test_walk: caller specific callback function to determine whether + * we walk over the current vma or not. Returning 0 means + * "do page table walk over the current vma", returning + * a negative value means "abort current page table walk + * right now" and returning 1 means "skip the current vma" + * @pre_vma: if set, called before starting walk on a non-null vma. + * @post_vma: if set, called after a walk on a non-null vma, provided + * that @pre_vma and the vma walk succeeded. + * + * p?d_entry callbacks are called even if those levels are folded on a + * particular architecture/configuration. + */ +struct mm_walk_ops { + int (*pgd_entry)(pgd_t *pgd, unsigned long addr, + unsigned long next, struct mm_walk *walk); + int (*p4d_entry)(p4d_t *p4d, unsigned long addr, + unsigned long next, struct mm_walk *walk); + int (*pud_entry)(pud_t *pud, unsigned long addr, + unsigned long next, struct mm_walk *walk); + int (*pmd_entry)(pmd_t *pmd, unsigned long addr, + unsigned long next, struct mm_walk *walk); + int (*pte_entry)(pte_t *pte, unsigned long addr, + unsigned long next, struct mm_walk *walk); + int (*pte_hole)(unsigned long addr, unsigned long next, + int depth, struct mm_walk *walk); + int (*hugetlb_entry)(pte_t *pte, unsigned long hmask, + unsigned long addr, unsigned long next, + struct mm_walk *walk); + int (*test_walk)(unsigned long addr, unsigned long next, + struct mm_walk *walk); + int (*pre_vma)(unsigned long start, unsigned long end, + struct mm_walk *walk); + void (*post_vma)(struct mm_walk *walk); +}; + +/* + * Action for pud_entry / pmd_entry callbacks. + * ACTION_SUBTREE is the default + */ +enum page_walk_action { + /* Descend to next level, splitting huge pages if needed and possible */ + ACTION_SUBTREE = 0, + /* Continue to next entry at this level (ignoring any subtree) */ + ACTION_CONTINUE = 1, + /* Call again for this entry */ + ACTION_AGAIN = 2 +}; + +/** + * struct mm_walk - walk_page_range data + * @ops: operation to call during the walk + * @mm: mm_struct representing the target process of page table walk + * @pgd: pointer to PGD; only valid with no_vma (otherwise set to NULL) + * @vma: vma currently walked (NULL if walking outside vmas) + * @action: next action to perform (see enum page_walk_action) + * @no_vma: walk ignoring vmas (vma will always be NULL) + * @private: private data for callbacks' usage + * + * (see the comment on walk_page_range() for more details) + */ +struct mm_walk { + const struct mm_walk_ops *ops; + struct mm_struct *mm; + pgd_t *pgd; + struct vm_area_struct *vma; + enum page_walk_action action; + bool no_vma; + void *private; +}; + +int walk_page_range(struct mm_struct *mm, unsigned long start, + unsigned long end, const struct mm_walk_ops *ops, + void *private); +int walk_page_range_novma(struct mm_struct *mm, unsigned long start, + unsigned long end, const struct mm_walk_ops *ops, + pgd_t *pgd, + void *private); +int walk_page_vma(struct vm_area_struct *vma, const struct mm_walk_ops *ops, + void *private); +int walk_page_mapping(struct address_space *mapping, pgoff_t first_index, + pgoff_t nr, const struct mm_walk_ops *ops, + void *private); + +#endif /* _LINUX_PAGEWALK_H */ |