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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * include/linux/userfaultfd_k.h
4 *
5 * Copyright (C) 2015 Red Hat, Inc.
6 *
7 */
8
9#ifndef _LINUX_USERFAULTFD_K_H
10#define _LINUX_USERFAULTFD_K_H
11
12#ifdef CONFIG_USERFAULTFD
13
14#include <linux/userfaultfd.h> /* linux/include/uapi/linux/userfaultfd.h */
15
16#include <linux/fcntl.h>
17#include <linux/mm.h>
18#include <asm-generic/pgtable_uffd.h>
19
20/*
21 * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
22 * new flags, since they might collide with O_* ones. We want
23 * to re-use O_* flags that couldn't possibly have a meaning
24 * from userfaultfd, in order to leave a free define-space for
25 * shared O_* flags.
26 */
27#define UFFD_CLOEXEC O_CLOEXEC
28#define UFFD_NONBLOCK O_NONBLOCK
29
30#define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
31#define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS)
32
33extern int sysctl_unprivileged_userfaultfd;
34
35extern vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason);
36
37extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start,
38 unsigned long src_start, unsigned long len,
39 bool *mmap_changing, __u64 mode);
40extern ssize_t mfill_zeropage(struct mm_struct *dst_mm,
41 unsigned long dst_start,
42 unsigned long len,
43 bool *mmap_changing);
44extern int mwriteprotect_range(struct mm_struct *dst_mm,
45 unsigned long start, unsigned long len,
46 bool enable_wp, bool *mmap_changing);
47
48/* mm helpers */
49static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
50 struct vm_userfaultfd_ctx vm_ctx)
51{
52 return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx;
53}
54
55static inline bool userfaultfd_missing(struct vm_area_struct *vma)
56{
57 return vma->vm_flags & VM_UFFD_MISSING;
58}
59
60static inline bool userfaultfd_wp(struct vm_area_struct *vma)
61{
62 return vma->vm_flags & VM_UFFD_WP;
63}
64
65static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma,
66 pte_t pte)
67{
68 return userfaultfd_wp(vma) && pte_uffd_wp(pte);
69}
70
71static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma,
72 pmd_t pmd)
73{
74 return userfaultfd_wp(vma) && pmd_uffd_wp(pmd);
75}
76
77static inline bool userfaultfd_armed(struct vm_area_struct *vma)
78{
79 return vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP);
80}
81
82extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *);
83extern void dup_userfaultfd_complete(struct list_head *);
84
85extern void mremap_userfaultfd_prep(struct vm_area_struct *,
86 struct vm_userfaultfd_ctx *);
87extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *,
88 unsigned long from, unsigned long to,
89 unsigned long len);
90
91extern bool userfaultfd_remove(struct vm_area_struct *vma,
92 unsigned long start,
93 unsigned long end);
94
95extern int userfaultfd_unmap_prep(struct vm_area_struct *vma,
96 unsigned long start, unsigned long end,
97 struct list_head *uf);
98extern void userfaultfd_unmap_complete(struct mm_struct *mm,
99 struct list_head *uf);
100
101#else /* CONFIG_USERFAULTFD */
102
103/* mm helpers */
104static inline vm_fault_t handle_userfault(struct vm_fault *vmf,
105 unsigned long reason)
106{
107 return VM_FAULT_SIGBUS;
108}
109
110static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
111 struct vm_userfaultfd_ctx vm_ctx)
112{
113 return true;
114}
115
116static inline bool userfaultfd_missing(struct vm_area_struct *vma)
117{
118 return false;
119}
120
121static inline bool userfaultfd_wp(struct vm_area_struct *vma)
122{
123 return false;
124}
125
126static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma,
127 pte_t pte)
128{
129 return false;
130}
131
132static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma,
133 pmd_t pmd)
134{
135 return false;
136}
137
138
139static inline bool userfaultfd_armed(struct vm_area_struct *vma)
140{
141 return false;
142}
143
144static inline int dup_userfaultfd(struct vm_area_struct *vma,
145 struct list_head *l)
146{
147 return 0;
148}
149
150static inline void dup_userfaultfd_complete(struct list_head *l)
151{
152}
153
154static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma,
155 struct vm_userfaultfd_ctx *ctx)
156{
157}
158
159static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx,
160 unsigned long from,
161 unsigned long to,
162 unsigned long len)
163{
164}
165
166static inline bool userfaultfd_remove(struct vm_area_struct *vma,
167 unsigned long start,
168 unsigned long end)
169{
170 return true;
171}
172
173static inline int userfaultfd_unmap_prep(struct vm_area_struct *vma,
174 unsigned long start, unsigned long end,
175 struct list_head *uf)
176{
177 return 0;
178}
179
180static inline void userfaultfd_unmap_complete(struct mm_struct *mm,
181 struct list_head *uf)
182{
183}
184
185#endif /* CONFIG_USERFAULTFD */
186
187#endif /* _LINUX_USERFAULTFD_K_H */