1/* Definitions for POSIX memory map interface. Linux generic version.
2 Copyright (C) 2001-2026 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#ifndef _SYS_MMAN_H
20# error "Never use <bits/mman-linux.h> directly; include <sys/mman.h> instead."
21#endif
22
23/* The following definitions basically come from the kernel headers.
24 But the kernel header is not namespace clean. */
25
26
27/* Protections are chosen from these bits, OR'd together. The
28 implementation does not necessarily support PROT_EXEC or PROT_WRITE
29 without PROT_READ. The only guarantees are that no writing will be
30 allowed without PROT_WRITE and no access will be allowed for PROT_NONE. */
31
32#define PROT_READ 0x1 /* Page can be read. */
33#define PROT_WRITE 0x2 /* Page can be written. */
34#define PROT_EXEC 0x4 /* Page can be executed. */
35#define PROT_NONE 0x0 /* Page can not be accessed. */
36#define PROT_GROWSDOWN 0x01000000 /* Extend change to start of
37 growsdown vma (mprotect only). */
38#define PROT_GROWSUP 0x02000000 /* Extend change to start of
39 growsup vma (mprotect only). */
40
41/* Sharing types (must choose one and only one of these). */
42#define MAP_SHARED 0x01 /* Share changes. */
43#define MAP_PRIVATE 0x02 /* Changes are private. */
44#define MAP_SHARED_VALIDATE 0x03 /* Share changes and validate
45 extension flags. */
46#define MAP_DROPPABLE 0x08 /* Zero memory under memory pressure. */
47#define MAP_TYPE 0x0f /* Mask for type of mapping. */
48
49/* Other flags. */
50#define MAP_FIXED 0x10 /* Interpret addr exactly. */
51#define MAP_FILE 0
52#ifdef __MAP_ANONYMOUS
53# define MAP_ANONYMOUS __MAP_ANONYMOUS /* Don't use a file. */
54#else
55# define MAP_ANONYMOUS 0x20 /* Don't use a file. */
56#endif
57#define MAP_ANON MAP_ANONYMOUS
58
59/* When MAP_HUGETLB is set, bits [26:31] encode the log2 of the huge page size.
60 The following definitions are associated with this huge page size encoding.
61 It is responsibility of the application to know which sizes are supported on
62 the running system. See mmap(2) man page for details. */
63
64#define MAP_HUGE_SHIFT 26
65#define MAP_HUGE_MASK 0x3f
66
67#define MAP_HUGE_16KB (14 << MAP_HUGE_SHIFT)
68#define MAP_HUGE_64KB (16 << MAP_HUGE_SHIFT)
69#define MAP_HUGE_512KB (19 << MAP_HUGE_SHIFT)
70#define MAP_HUGE_1MB (20 << MAP_HUGE_SHIFT)
71#define MAP_HUGE_2MB (21 << MAP_HUGE_SHIFT)
72#define MAP_HUGE_8MB (23 << MAP_HUGE_SHIFT)
73#define MAP_HUGE_16MB (24 << MAP_HUGE_SHIFT)
74#define MAP_HUGE_32MB (25 << MAP_HUGE_SHIFT)
75#define MAP_HUGE_256MB (28 << MAP_HUGE_SHIFT)
76#define MAP_HUGE_512MB (29 << MAP_HUGE_SHIFT)
77#define MAP_HUGE_1GB (30 << MAP_HUGE_SHIFT)
78#define MAP_HUGE_2GB (31 << MAP_HUGE_SHIFT)
79#define MAP_HUGE_16GB (34U << MAP_HUGE_SHIFT)
80
81/* Flags to `msync'. */
82#define MS_ASYNC 1 /* Sync memory asynchronously. */
83#define MS_SYNC 4 /* Synchronous memory sync. */
84#define MS_INVALIDATE 2 /* Invalidate the caches. */
85
86/* Advice to `madvise'. */
87#ifdef __USE_MISC
88# define MADV_NORMAL 0 /* No further special treatment. */
89# define MADV_RANDOM 1 /* Expect random page references. */
90# define MADV_SEQUENTIAL 2 /* Expect sequential page references. */
91# define MADV_WILLNEED 3 /* Will need these pages. */
92# define MADV_DONTNEED 4 /* Don't need these pages. */
93# define MADV_FREE 8 /* Free pages only if memory pressure. */
94# define MADV_REMOVE 9 /* Remove these pages and resources. */
95# define MADV_DONTFORK 10 /* Do not inherit across fork. */
96# define MADV_DOFORK 11 /* Do inherit across fork. */
97# define MADV_MERGEABLE 12 /* KSM may merge identical pages. */
98# define MADV_UNMERGEABLE 13 /* KSM may not merge identical pages. */
99# define MADV_HUGEPAGE 14 /* Worth backing with hugepages. */
100# define MADV_NOHUGEPAGE 15 /* Not worth backing with hugepages. */
101# define MADV_DONTDUMP 16 /* Explicitly exclude from the core dump,
102 overrides the coredump filter bits. */
103# define MADV_DODUMP 17 /* Clear the MADV_DONTDUMP flag. */
104# define MADV_WIPEONFORK 18 /* Zero memory on fork, child only. */
105# define MADV_KEEPONFORK 19 /* Undo MADV_WIPEONFORK. */
106# define MADV_COLD 20 /* Deactivate these pages. */
107# define MADV_PAGEOUT 21 /* Reclaim these pages. */
108# define MADV_POPULATE_READ 22 /* Populate (prefault) page tables
109 readable. */
110# define MADV_POPULATE_WRITE 23 /* Populate (prefault) page tables
111 writable. */
112# define MADV_DONTNEED_LOCKED 24 /* Like MADV_DONTNEED, but drop
113 locked pages too. */
114# define MADV_COLLAPSE 25 /* Synchronous hugepage collapse. */
115# define MADV_HWPOISON 100 /* Poison a page for testing. */
116# define MADV_GUARD_INSTALL 102 /* Fatal signal on access to range */
117# define MADV_GUARD_REMOVE 103 /* Unguard range */
118#endif
119
120/* The POSIX people had to invent similar names for the same things. */
121#ifdef __USE_XOPEN2K
122# define POSIX_MADV_NORMAL 0 /* No further special treatment. */
123# define POSIX_MADV_RANDOM 1 /* Expect random page references. */
124# define POSIX_MADV_SEQUENTIAL 2 /* Expect sequential page references. */
125# define POSIX_MADV_WILLNEED 3 /* Will need these pages. */
126# define POSIX_MADV_DONTNEED 4 /* Don't need these pages. */
127#endif
128
129/* Flags for `mlockall'. */
130#ifndef MCL_CURRENT
131# define MCL_CURRENT 1 /* Lock all currently mapped pages. */
132# define MCL_FUTURE 2 /* Lock all additions to address
133 space. */
134# define MCL_ONFAULT 4 /* Lock all pages that are
135 faulted in. */
136#endif
137
138#include <bits/mman-shared.h>