Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_PAGEWALK_H
3#define _LINUX_PAGEWALK_H
4
5#include <linux/mm.h>
6
7struct mm_walk;
8
9/**
10 * struct mm_walk_ops - callbacks for walk_page_range
11 * @pgd_entry: if set, called for each non-empty PGD (top-level) entry
12 * @p4d_entry: if set, called for each non-empty P4D entry
13 * @pud_entry: if set, called for each non-empty PUD entry
14 * @pmd_entry: if set, called for each non-empty PMD entry
15 * this handler is required to be able to handle
16 * pmd_trans_huge() pmds. They may simply choose to
17 * split_huge_page() instead of handling it explicitly.
18 * @pte_entry: if set, called for each PTE (lowest-level) entry,
19 * including empty ones
20 * @pte_hole: if set, called for each hole at all levels,
21 * depth is -1 if not known, 0:PGD, 1:P4D, 2:PUD, 3:PMD.
22 * Any folded depths (where PTRS_PER_P?D is equal to 1)
23 * are skipped.
24 * @hugetlb_entry: if set, called for each hugetlb entry
25 * @test_walk: caller specific callback function to determine whether
26 * we walk over the current vma or not. Returning 0 means
27 * "do page table walk over the current vma", returning
28 * a negative value means "abort current page table walk
29 * right now" and returning 1 means "skip the current vma"
30 * Note that this callback is not called when the caller
31 * passes in a single VMA as for walk_page_vma().
32 * @pre_vma: if set, called before starting walk on a non-null vma.
33 * @post_vma: if set, called after a walk on a non-null vma, provided
34 * that @pre_vma and the vma walk succeeded.
35 *
36 * p?d_entry callbacks are called even if those levels are folded on a
37 * particular architecture/configuration.
38 */
39struct mm_walk_ops {
40 int (*pgd_entry)(pgd_t *pgd, unsigned long addr,
41 unsigned long next, struct mm_walk *walk);
42 int (*p4d_entry)(p4d_t *p4d, unsigned long addr,
43 unsigned long next, struct mm_walk *walk);
44 int (*pud_entry)(pud_t *pud, unsigned long addr,
45 unsigned long next, struct mm_walk *walk);
46 int (*pmd_entry)(pmd_t *pmd, unsigned long addr,
47 unsigned long next, struct mm_walk *walk);
48 int (*pte_entry)(pte_t *pte, unsigned long addr,
49 unsigned long next, struct mm_walk *walk);
50 int (*pte_hole)(unsigned long addr, unsigned long next,
51 int depth, struct mm_walk *walk);
52 int (*hugetlb_entry)(pte_t *pte, unsigned long hmask,
53 unsigned long addr, unsigned long next,
54 struct mm_walk *walk);
55 int (*test_walk)(unsigned long addr, unsigned long next,
56 struct mm_walk *walk);
57 int (*pre_vma)(unsigned long start, unsigned long end,
58 struct mm_walk *walk);
59 void (*post_vma)(struct mm_walk *walk);
60};
61
62/*
63 * Action for pud_entry / pmd_entry callbacks.
64 * ACTION_SUBTREE is the default
65 */
66enum page_walk_action {
67 /* Descend to next level, splitting huge pages if needed and possible */
68 ACTION_SUBTREE = 0,
69 /* Continue to next entry at this level (ignoring any subtree) */
70 ACTION_CONTINUE = 1,
71 /* Call again for this entry */
72 ACTION_AGAIN = 2
73};
74
75/**
76 * struct mm_walk - walk_page_range data
77 * @ops: operation to call during the walk
78 * @mm: mm_struct representing the target process of page table walk
79 * @pgd: pointer to PGD; only valid with no_vma (otherwise set to NULL)
80 * @vma: vma currently walked (NULL if walking outside vmas)
81 * @action: next action to perform (see enum page_walk_action)
82 * @no_vma: walk ignoring vmas (vma will always be NULL)
83 * @private: private data for callbacks' usage
84 *
85 * (see the comment on walk_page_range() for more details)
86 */
87struct mm_walk {
88 const struct mm_walk_ops *ops;
89 struct mm_struct *mm;
90 pgd_t *pgd;
91 struct vm_area_struct *vma;
92 enum page_walk_action action;
93 bool no_vma;
94 void *private;
95};
96
97int walk_page_range(struct mm_struct *mm, unsigned long start,
98 unsigned long end, const struct mm_walk_ops *ops,
99 void *private);
100int walk_page_range_novma(struct mm_struct *mm, unsigned long start,
101 unsigned long end, const struct mm_walk_ops *ops,
102 pgd_t *pgd,
103 void *private);
104int walk_page_range_vma(struct vm_area_struct *vma, unsigned long start,
105 unsigned long end, const struct mm_walk_ops *ops,
106 void *private);
107int walk_page_vma(struct vm_area_struct *vma, const struct mm_walk_ops *ops,
108 void *private);
109int walk_page_mapping(struct address_space *mapping, pgoff_t first_index,
110 pgoff_t nr, const struct mm_walk_ops *ops,
111 void *private);
112
113#endif /* _LINUX_PAGEWALK_H */