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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 #define LEGACY_MAP_MASK (MAP_SHARED \
36 		| MAP_PRIVATE \
37 		| MAP_FIXED \
38 		| MAP_ANONYMOUS \
39 		| MAP_DENYWRITE \
40 		| MAP_EXECUTABLE \
41 		| MAP_UNINITIALIZED \
42 		| MAP_GROWSDOWN \
43 		| MAP_LOCKED \
44 		| MAP_NORESERVE \
45 		| MAP_POPULATE \
46 		| MAP_NONBLOCK \
47 		| MAP_STACK \
48 		| MAP_HUGETLB \
49 		| MAP_32BIT \
50 		| MAP_HUGE_2MB \
51 		| MAP_HUGE_1GB)
52 
53 extern int sysctl_overcommit_memory;
54 extern int sysctl_overcommit_ratio;
55 extern unsigned long sysctl_overcommit_kbytes;
56 extern struct percpu_counter vm_committed_as;
57 
58 #ifdef CONFIG_SMP
59 extern s32 vm_committed_as_batch;
60 extern void mm_compute_batch(int overcommit_policy);
61 #else
62 #define vm_committed_as_batch 0
mm_compute_batch(int overcommit_policy)63 static inline void mm_compute_batch(int overcommit_policy)
64 {
65 }
66 #endif
67 
68 unsigned long vm_memory_committed(void);
69 
vm_acct_memory(long pages)70 static inline void vm_acct_memory(long pages)
71 {
72 	percpu_counter_add_batch(&vm_committed_as, pages, vm_committed_as_batch);
73 }
74 
vm_unacct_memory(long pages)75 static inline void vm_unacct_memory(long pages)
76 {
77 	vm_acct_memory(-pages);
78 }
79 
80 /*
81  * Allow architectures to handle additional protection and flag bits. The
82  * overriding macros must be defined in the arch-specific asm/mman.h file.
83  */
84 
85 #ifndef arch_calc_vm_prot_bits
86 #define arch_calc_vm_prot_bits(prot, pkey) 0
87 #endif
88 
89 #ifndef arch_calc_vm_flag_bits
90 #define arch_calc_vm_flag_bits(flags) 0
91 #endif
92 
93 #ifndef arch_vm_get_page_prot
94 #define arch_vm_get_page_prot(vm_flags) __pgprot(0)
95 #endif
96 
97 #ifndef arch_validate_prot
98 /*
99  * This is called from mprotect().  PROT_GROWSDOWN and PROT_GROWSUP have
100  * already been masked out.
101  *
102  * Returns true if the prot flags are valid
103  */
arch_validate_prot(unsigned long prot,unsigned long addr)104 static inline bool arch_validate_prot(unsigned long prot, unsigned long addr)
105 {
106 	return (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) == 0;
107 }
108 #define arch_validate_prot arch_validate_prot
109 #endif
110 
111 #ifndef arch_validate_flags
112 /*
113  * This is called from mmap() and mprotect() with the updated vma->vm_flags.
114  *
115  * Returns true if the VM_* flags are valid.
116  */
arch_validate_flags(unsigned long flags)117 static inline bool arch_validate_flags(unsigned long flags)
118 {
119 	return true;
120 }
121 #define arch_validate_flags arch_validate_flags
122 #endif
123 
124 /*
125  * Optimisation macro.  It is equivalent to:
126  *      (x & bit1) ? bit2 : 0
127  * but this version is faster.
128  * ("bit1" and "bit2" must be single bits)
129  */
130 #define _calc_vm_trans(x, bit1, bit2) \
131   ((!(bit1) || !(bit2)) ? 0 : \
132   ((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \
133    : ((x) & (bit1)) / ((bit1) / (bit2))))
134 
135 /*
136  * Combine the mmap "prot" argument into "vm_flags" used internally.
137  */
138 static inline unsigned long
calc_vm_prot_bits(unsigned long prot,unsigned long pkey)139 calc_vm_prot_bits(unsigned long prot, unsigned long pkey)
140 {
141 	return _calc_vm_trans(prot, PROT_READ,  VM_READ ) |
142 	       _calc_vm_trans(prot, PROT_WRITE, VM_WRITE) |
143 	       _calc_vm_trans(prot, PROT_EXEC,  VM_EXEC) |
144 	       arch_calc_vm_prot_bits(prot, pkey);
145 }
146 
147 /*
148  * Combine the mmap "flags" argument into "vm_flags" used internally.
149  */
150 static inline unsigned long
calc_vm_flag_bits(unsigned long flags)151 calc_vm_flag_bits(unsigned long flags)
152 {
153 	return _calc_vm_trans(flags, MAP_GROWSDOWN,  VM_GROWSDOWN ) |
154 	       _calc_vm_trans(flags, MAP_DENYWRITE,  VM_DENYWRITE ) |
155 	       _calc_vm_trans(flags, MAP_LOCKED,     VM_LOCKED    ) |
156 	       _calc_vm_trans(flags, MAP_SYNC,	     VM_SYNC      ) |
157 	       arch_calc_vm_flag_bits(flags);
158 }
159 
160 unsigned long vm_commit_limit(void);
161 #endif /* _LINUX_MMAN_H */
162