xref: /openbmc/linux/include/linux/pagewalk.h (revision 0a04480d)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_PAGEWALK_H
3 #define _LINUX_PAGEWALK_H
4 
5 #include <linux/mm.h>
6 
7 struct mm_walk;
8 
9 /**
10  * mm_walk_ops - callbacks for walk_page_range
11  * @pud_entry:		if set, called for each non-empty PUD (2nd-level) entry
12  *			this handler should only handle pud_trans_huge() puds.
13  *			the pmd_entry or pte_entry callbacks will be used for
14  *			regular PUDs.
15  * @pmd_entry:		if set, called for each non-empty PMD (3rd-level) entry
16  *			this handler is required to be able to handle
17  *			pmd_trans_huge() pmds.  They may simply choose to
18  *			split_huge_page() instead of handling it explicitly.
19  * @pte_entry:		if set, called for each non-empty PTE (4th-level) entry
20  * @pte_hole:		if set, called for each hole at all levels
21  * @hugetlb_entry:	if set, called for each hugetlb entry
22  * @test_walk:		caller specific callback function to determine whether
23  *			we walk over the current vma or not. Returning 0 means
24  *			"do page table walk over the current vma", returning
25  *			a negative value means "abort current page table walk
26  *			right now" and returning 1 means "skip the current vma"
27  */
28 struct mm_walk_ops {
29 	int (*pud_entry)(pud_t *pud, unsigned long addr,
30 			 unsigned long next, struct mm_walk *walk);
31 	int (*pmd_entry)(pmd_t *pmd, unsigned long addr,
32 			 unsigned long next, struct mm_walk *walk);
33 	int (*pte_entry)(pte_t *pte, unsigned long addr,
34 			 unsigned long next, struct mm_walk *walk);
35 	int (*pte_hole)(unsigned long addr, unsigned long next,
36 			struct mm_walk *walk);
37 	int (*hugetlb_entry)(pte_t *pte, unsigned long hmask,
38 			     unsigned long addr, unsigned long next,
39 			     struct mm_walk *walk);
40 	int (*test_walk)(unsigned long addr, unsigned long next,
41 			struct mm_walk *walk);
42 };
43 
44 /**
45  * mm_walk - walk_page_range data
46  * @ops:	operation to call during the walk
47  * @mm:		mm_struct representing the target process of page table walk
48  * @vma:	vma currently walked (NULL if walking outside vmas)
49  * @private:	private data for callbacks' usage
50  *
51  * (see the comment on walk_page_range() for more details)
52  */
53 struct mm_walk {
54 	const struct mm_walk_ops *ops;
55 	struct mm_struct *mm;
56 	struct vm_area_struct *vma;
57 	void *private;
58 };
59 
60 int walk_page_range(struct mm_struct *mm, unsigned long start,
61 		unsigned long end, const struct mm_walk_ops *ops,
62 		void *private);
63 int walk_page_vma(struct vm_area_struct *vma, const struct mm_walk_ops *ops,
64 		void *private);
65 
66 #endif /* _LINUX_PAGEWALK_H */
67