1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_MMAN_H
3 #define _LINUX_MMAN_H
4
5 #include <linux/mm.h>
6 #include <linux/percpu_counter.h>
7
8 #include <linux/atomic.h>
9 #include <uapi/linux/mman.h>
10
11 /*
12 * Arrange for legacy / undefined architecture specific flags to be
13 * ignored by mmap handling code.
14 */
15 #ifndef MAP_32BIT
16 #define MAP_32BIT 0
17 #endif
18 #ifndef MAP_HUGE_2MB
19 #define MAP_HUGE_2MB 0
20 #endif
21 #ifndef MAP_HUGE_1GB
22 #define MAP_HUGE_1GB 0
23 #endif
24 #ifndef MAP_UNINITIALIZED
25 #define MAP_UNINITIALIZED 0
26 #endif
27 #ifndef MAP_SYNC
28 #define MAP_SYNC 0
29 #endif
30
31 /*
32 * The historical set of flags that all mmap implementations implicitly
33 * support when a ->mmap_validate() op is not provided in file_operations.
34 *
35 * MAP_EXECUTABLE and MAP_DENYWRITE are completely ignored throughout the
36 * kernel.
37 */
38 #define LEGACY_MAP_MASK (MAP_SHARED \
39 | MAP_PRIVATE \
40 | MAP_FIXED \
41 | MAP_ANONYMOUS \
42 | MAP_DENYWRITE \
43 | MAP_EXECUTABLE \
44 | MAP_UNINITIALIZED \
45 | MAP_GROWSDOWN \
46 | MAP_LOCKED \
47 | MAP_NORESERVE \
48 | MAP_POPULATE \
49 | MAP_NONBLOCK \
50 | MAP_STACK \
51 | MAP_HUGETLB \
52 | MAP_32BIT \
53 | MAP_HUGE_2MB \
54 | MAP_HUGE_1GB)
55
56 extern int sysctl_overcommit_memory;
57 extern int sysctl_overcommit_ratio;
58 extern unsigned long sysctl_overcommit_kbytes;
59 extern struct percpu_counter vm_committed_as;
60
61 #ifdef CONFIG_SMP
62 extern s32 vm_committed_as_batch;
63 extern void mm_compute_batch(int overcommit_policy);
64 #else
65 #define vm_committed_as_batch 0
mm_compute_batch(int overcommit_policy)66 static inline void mm_compute_batch(int overcommit_policy)
67 {
68 }
69 #endif
70
71 unsigned long vm_memory_committed(void);
72
vm_acct_memory(long pages)73 static inline void vm_acct_memory(long pages)
74 {
75 percpu_counter_add_batch(&vm_committed_as, pages, vm_committed_as_batch);
76 }
77
vm_unacct_memory(long pages)78 static inline void vm_unacct_memory(long pages)
79 {
80 vm_acct_memory(-pages);
81 }
82
83 /*
84 * Allow architectures to handle additional protection and flag bits. The
85 * overriding macros must be defined in the arch-specific asm/mman.h file.
86 */
87
88 #ifndef arch_calc_vm_prot_bits
89 #define arch_calc_vm_prot_bits(prot, pkey) 0
90 #endif
91
92 #ifndef arch_calc_vm_flag_bits
93 #define arch_calc_vm_flag_bits(flags) 0
94 #endif
95
96 #ifndef arch_validate_prot
97 /*
98 * This is called from mprotect(). PROT_GROWSDOWN and PROT_GROWSUP have
99 * already been masked out.
100 *
101 * Returns true if the prot flags are valid
102 */
arch_validate_prot(unsigned long prot,unsigned long addr)103 static inline bool arch_validate_prot(unsigned long prot, unsigned long addr)
104 {
105 return (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) == 0;
106 }
107 #define arch_validate_prot arch_validate_prot
108 #endif
109
110 #ifndef arch_validate_flags
111 /*
112 * This is called from mmap() and mprotect() with the updated vma->vm_flags.
113 *
114 * Returns true if the VM_* flags are valid.
115 */
arch_validate_flags(unsigned long flags)116 static inline bool arch_validate_flags(unsigned long flags)
117 {
118 return true;
119 }
120 #define arch_validate_flags arch_validate_flags
121 #endif
122
123 /*
124 * Optimisation macro. It is equivalent to:
125 * (x & bit1) ? bit2 : 0
126 * but this version is faster.
127 * ("bit1" and "bit2" must be single bits)
128 */
129 #define _calc_vm_trans(x, bit1, bit2) \
130 ((!(bit1) || !(bit2)) ? 0 : \
131 ((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \
132 : ((x) & (bit1)) / ((bit1) / (bit2))))
133
134 /*
135 * Combine the mmap "prot" argument into "vm_flags" used internally.
136 */
137 static inline unsigned long
calc_vm_prot_bits(unsigned long prot,unsigned long pkey)138 calc_vm_prot_bits(unsigned long prot, unsigned long pkey)
139 {
140 return _calc_vm_trans(prot, PROT_READ, VM_READ ) |
141 _calc_vm_trans(prot, PROT_WRITE, VM_WRITE) |
142 _calc_vm_trans(prot, PROT_EXEC, VM_EXEC) |
143 arch_calc_vm_prot_bits(prot, pkey);
144 }
145
146 /*
147 * Combine the mmap "flags" argument into "vm_flags" used internally.
148 */
149 static inline unsigned long
calc_vm_flag_bits(unsigned long flags)150 calc_vm_flag_bits(unsigned long flags)
151 {
152 return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) |
153 _calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED ) |
154 _calc_vm_trans(flags, MAP_SYNC, VM_SYNC ) |
155 arch_calc_vm_flag_bits(flags);
156 }
157
158 unsigned long vm_commit_limit(void);
159 #endif /* _LINUX_MMAN_H */
160
