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Merge tag 'omap-fixes-audio-clock-and-modem-signed' of git://git.kernel.org/pub/scm...
[linux-2.6-block.git] / include / linux / userfaultfd_k.h
CommitLineData
b2441318 1/* SPDX-License-Identifier: GPL-2.0 */
932b18e0
AA		 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>
55adf4de 17#include <linux/mm.h>
1db9dbc2
PX		 18#include <linux/swap.h>
19#include <linux/swapops.h>
55adf4de 20#include <asm-generic/pgtable_uffd.h>
b1f9e876 21#include <linux/hugetlb_inline.h>
932b18e0 22
7677f7fd
AR		 23/* The set of all possible UFFD-related VM flags. */
24#define __VM_UFFD_FLAGS (VM_UFFD_MISSING | VM_UFFD_WP | VM_UFFD_MINOR)
25
932b18e0
AA		 26/*
27 * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
28 * new flags, since they might collide with O_* ones. We want
29 * to re-use O_* flags that couldn't possibly have a meaning
30 * from userfaultfd, in order to leave a free define-space for
31 * shared O_* flags.
32 */
33#define UFFD_CLOEXEC O_CLOEXEC
34#define UFFD_NONBLOCK O_NONBLOCK
35
36#define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
37#define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS)
38
2b740303 39extern vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason);
932b18e0 40
d9712937
AR		 41/* A combined operation mode + behavior flags. */
42typedef unsigned int __bitwise uffd_flags_t;
43
44/* Mutually exclusive modes of operation. */
45enum mfill_atomic_mode {
46 MFILL_ATOMIC_COPY,
47 MFILL_ATOMIC_ZEROPAGE,
48 MFILL_ATOMIC_CONTINUE,
fc71884a 49 MFILL_ATOMIC_POISON,
d9712937 50 NR_MFILL_ATOMIC_MODES,
f6191471
AR		 51};
52
d9712937
AR		 53#define MFILL_ATOMIC_MODE_BITS (const_ilog2(NR_MFILL_ATOMIC_MODES - 1) + 1)
54#define MFILL_ATOMIC_BIT(nr) BIT(MFILL_ATOMIC_MODE_BITS + (nr))
55#define MFILL_ATOMIC_FLAG(nr) ((__force uffd_flags_t) MFILL_ATOMIC_BIT(nr))
56#define MFILL_ATOMIC_MODE_MASK ((__force uffd_flags_t) (MFILL_ATOMIC_BIT(0) - 1))
57
58static inline bool uffd_flags_mode_is(uffd_flags_t flags, enum mfill_atomic_mode expected)
59{
60 return (flags & MFILL_ATOMIC_MODE_MASK) == ((__force uffd_flags_t) expected);
61}
62
63static inline uffd_flags_t uffd_flags_set_mode(uffd_flags_t flags, enum mfill_atomic_mode mode)
64{
65 flags &= ~MFILL_ATOMIC_MODE_MASK;
66 return flags | ((__force uffd_flags_t) mode);
67}
68
69/* Flags controlling behavior. These behavior changes are mode-independent. */
70#define MFILL_ATOMIC_WP MFILL_ATOMIC_FLAG(0)
71
61c50040 72extern int mfill_atomic_install_pte(pmd_t *dst_pmd,
7d64ae3a
AR		 73 struct vm_area_struct *dst_vma,
74 unsigned long dst_addr, struct page *page,
d9712937 75 bool newly_allocated, uffd_flags_t flags);
7d64ae3a 76
a734991c
AR		 77extern ssize_t mfill_atomic_copy(struct mm_struct *dst_mm, unsigned long dst_start,
78 unsigned long src_start, unsigned long len,
d9712937 79 atomic_t *mmap_changing, uffd_flags_t flags);
a734991c
AR		 80extern ssize_t mfill_atomic_zeropage(struct mm_struct *dst_mm,
81 unsigned long dst_start,
82 unsigned long len,
83 atomic_t *mmap_changing);
84extern ssize_t mfill_atomic_continue(struct mm_struct *dst_mm, unsigned long dst_start,
02891844
AR		 85 unsigned long len, atomic_t *mmap_changing,
86 uffd_flags_t flags);
fc71884a
AR		 87extern ssize_t mfill_atomic_poison(struct mm_struct *dst_mm, unsigned long start,
88 unsigned long len, atomic_t *mmap_changing,
89 uffd_flags_t flags);
ffd05793
SL		 90extern int mwriteprotect_range(struct mm_struct *dst_mm,
91 unsigned long start, unsigned long len,
a759a909 92 bool enable_wp, atomic_t *mmap_changing);
61c50040 93extern long uffd_wp_range(struct vm_area_struct *vma,
f369b07c 94 unsigned long start, unsigned long len, bool enable_wp);
c1a4de99 95
932b18e0
AA		 96/* mm helpers */
97static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
98 struct vm_userfaultfd_ctx vm_ctx)
99{
100 return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx;
101}
102
c1991e07 103/*
0d9cadab
AR		 104 * Never enable huge pmd sharing on some uffd registered vmas:
105 *
106 * - VM_UFFD_WP VMAs, because write protect information is per pgtable entry.
107 *
108 * - VM_UFFD_MINOR VMAs, because otherwise we would never get minor faults for
109 * VMAs which share huge pmds. (If you have two mappings to the same
110 * underlying pages, and fault in the non-UFFD-registered one with a write,
111 * with huge pmd sharing this would *also* setup the second UFFD-registered
112 * mapping, and we'd not get minor faults.)
c1991e07
PX		 113 */
114static inline bool uffd_disable_huge_pmd_share(struct vm_area_struct *vma)
115{
0d9cadab 116 return vma->vm_flags & (VM_UFFD_WP | VM_UFFD_MINOR);
c1991e07
PX		 117}
118
9c28a205
PX		 119/*
120 * Don't do fault around for either WP or MINOR registered uffd range. For
121 * MINOR registered range, fault around will be a total disaster and ptes can
122 * be installed without notifications; for WP it should mostly be fine as long
123 * as the fault around checks for pte_none() before the installation, however
124 * to be super safe we just forbid it.
125 */
126static inline bool uffd_disable_fault_around(struct vm_area_struct *vma)
127{
128 return vma->vm_flags & (VM_UFFD_WP | VM_UFFD_MINOR);
129}
130
932b18e0
AA		 131static inline bool userfaultfd_missing(struct vm_area_struct *vma)
132{
133 return vma->vm_flags & VM_UFFD_MISSING;
134}
135
1df319e0
SL		 136static inline bool userfaultfd_wp(struct vm_area_struct *vma)
137{
138 return vma->vm_flags & VM_UFFD_WP;
139}
140
7677f7fd
AR		 141static inline bool userfaultfd_minor(struct vm_area_struct *vma)
142{
143 return vma->vm_flags & VM_UFFD_MINOR;
144}
145
55adf4de
AA		 146static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma,
147 pte_t pte)
148{
149 return userfaultfd_wp(vma) && pte_uffd_wp(pte);
150}
151
152static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma,
153 pmd_t pmd)
154{
155 return userfaultfd_wp(vma) && pmd_uffd_wp(pmd);
156}
157
932b18e0
AA		 158static inline bool userfaultfd_armed(struct vm_area_struct *vma)
159{
7677f7fd 160 return vma->vm_flags & __VM_UFFD_FLAGS;
932b18e0
AA		 161}
162
b1f9e876
PX		 163static inline bool vma_can_userfault(struct vm_area_struct *vma,
164 unsigned long vm_flags)
165{
67eae54b
PX		 166 if ((vm_flags & VM_UFFD_MINOR) &&
167 (!is_vm_hugetlb_page(vma) && !vma_is_shmem(vma)))
168 return false;
b1f9e876
PX		 169#ifndef CONFIG_PTE_MARKER_UFFD_WP
170 /*
171 * If user requested uffd-wp but not enabled pte markers for
172 * uffd-wp, then shmem & hugetlbfs are not supported but only
173 * anonymous.
174 */
175 if ((vm_flags & VM_UFFD_WP) && !vma_is_anonymous(vma))
176 return false;
177#endif
178 return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma) ||
179 vma_is_shmem(vma);
180}
181
893e26e6
PE		 182extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *);
183extern void dup_userfaultfd_complete(struct list_head *);
184
72f87654
PE		 185extern void mremap_userfaultfd_prep(struct vm_area_struct *,
186 struct vm_userfaultfd_ctx *);
90794bf1 187extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *,
72f87654
PE		 188 unsigned long from, unsigned long to,
189 unsigned long len);
190
70ccb92f 191extern bool userfaultfd_remove(struct vm_area_struct *vma,
d811914d
MR		 192 unsigned long start,
193 unsigned long end);
05ce7724 194
65ac1320
LH		 195extern int userfaultfd_unmap_prep(struct vm_area_struct *vma,
196 unsigned long start, unsigned long end, struct list_head *uf);
897ab3e0
MR		 197extern void userfaultfd_unmap_complete(struct mm_struct *mm,
198 struct list_head *uf);
2bad466c 199extern bool userfaultfd_wp_unpopulated(struct vm_area_struct *vma);
897ab3e0 200
932b18e0
AA		 201#else /* CONFIG_USERFAULTFD */
202
203/* mm helpers */
2b740303
SJ		 204static inline vm_fault_t handle_userfault(struct vm_fault *vmf,
205 unsigned long reason)
932b18e0
AA		 206{
207 return VM_FAULT_SIGBUS;
208}
209
210static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
211 struct vm_userfaultfd_ctx vm_ctx)
212{
213 return true;
214}
215
216static inline bool userfaultfd_missing(struct vm_area_struct *vma)
217{
218 return false;
219}
220
1df319e0
SL		 221static inline bool userfaultfd_wp(struct vm_area_struct *vma)
222{
223 return false;
224}
225
7677f7fd
AR		 226static inline bool userfaultfd_minor(struct vm_area_struct *vma)
227{
228 return false;
229}
230
55adf4de
AA		 231static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma,
232 pte_t pte)
233{
234 return false;
235}
236
237static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma,
238 pmd_t pmd)
239{
240 return false;
241}
242
243
932b18e0
AA		 244static inline bool userfaultfd_armed(struct vm_area_struct *vma)
245{
246 return false;
247}
248
893e26e6
PE		 249static inline int dup_userfaultfd(struct vm_area_struct *vma,
250 struct list_head *l)
251{
252 return 0;
253}
254
255static inline void dup_userfaultfd_complete(struct list_head *l)
256{
257}
258
72f87654
PE		 259static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma,
260 struct vm_userfaultfd_ctx *ctx)
261{
262}
263
90794bf1 264static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx,
72f87654
PE		 265 unsigned long from,
266 unsigned long to,
267 unsigned long len)
268{
269}
05ce7724 270
70ccb92f 271static inline bool userfaultfd_remove(struct vm_area_struct *vma,
d811914d
MR		 272 unsigned long start,
273 unsigned long end)
05ce7724 274{
70ccb92f 275 return true;
05ce7724 276}
897ab3e0 277
65ac1320 278static inline int userfaultfd_unmap_prep(struct vm_area_struct *vma,
897ab3e0
MR		 279 unsigned long start, unsigned long end,
280 struct list_head *uf)
281{
282 return 0;
283}
284
285static inline void userfaultfd_unmap_complete(struct mm_struct *mm,
286 struct list_head *uf)
287{
288}
ca49ca71 289
9c28a205
PX		 290static inline bool uffd_disable_fault_around(struct vm_area_struct *vma)
291{
292 return false;
293}
294
2bad466c
PX		 295static inline bool userfaultfd_wp_unpopulated(struct vm_area_struct *vma)
296{
297 return false;
298}
299
932b18e0
AA		 300#endif /* CONFIG_USERFAULTFD */
301
2bad466c
PX		 302static inline bool userfaultfd_wp_use_markers(struct vm_area_struct *vma)
303{
304 /* Only wr-protect mode uses pte markers */
305 if (!userfaultfd_wp(vma))
306 return false;
307
308 /* File-based uffd-wp always need markers */
309 if (!vma_is_anonymous(vma))
310 return true;
311
312 /*
313 * Anonymous uffd-wp only needs the markers if WP_UNPOPULATED
314 * enabled (to apply markers on zero pages).
315 */
316 return userfaultfd_wp_unpopulated(vma);
317}
318
1db9dbc2
PX		 319static inline bool pte_marker_entry_uffd_wp(swp_entry_t entry)
320{
321#ifdef CONFIG_PTE_MARKER_UFFD_WP
322 return is_pte_marker_entry(entry) &&
323 (pte_marker_get(entry) & PTE_MARKER_UFFD_WP);
324#else
325 return false;
326#endif
327}
328
329static inline bool pte_marker_uffd_wp(pte_t pte)
330{
331#ifdef CONFIG_PTE_MARKER_UFFD_WP
332 swp_entry_t entry;
333
334 if (!is_swap_pte(pte))
335 return false;
336
337 entry = pte_to_swp_entry(pte);
338
339 return pte_marker_entry_uffd_wp(entry);
340#else
341 return false;
342#endif
343}
344
345/*
346 * Returns true if this is a swap pte and was uffd-wp wr-protected in either
347 * forms (pte marker or a normal swap pte), false otherwise.
348 */
349static inline bool pte_swp_uffd_wp_any(pte_t pte)
350{
351#ifdef CONFIG_PTE_MARKER_UFFD_WP
352 if (!is_swap_pte(pte))
353 return false;
354
355 if (pte_swp_uffd_wp(pte))
356 return true;
357
358 if (pte_marker_uffd_wp(pte))
359 return true;
360#endif
361 return false;
362}
363
932b18e0 364#endif /* _LINUX_USERFAULTFD_K_H */
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