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_ABOVE4G 19 #define MAP_ABOVE4G 0 20 #endif 21 #ifndef MAP_HUGE_2MB 22 #define MAP_HUGE_2MB 0 23 #endif 24 #ifndef MAP_HUGE_1GB 25 #define MAP_HUGE_1GB 0 26 #endif 27 #ifndef MAP_UNINITIALIZED 28 #define MAP_UNINITIALIZED 0 29 #endif 30 #ifndef MAP_SYNC 31 #define MAP_SYNC 0 32 #endif 33 34 /* 35 * The historical set of flags that all mmap implementations implicitly 36 * support when a ->mmap_validate() op is not provided in file_operations. 37 * 38 * MAP_EXECUTABLE and MAP_DENYWRITE are completely ignored throughout the 39 * kernel. 40 */ 41 #define LEGACY_MAP_MASK (MAP_SHARED \ 42 | MAP_PRIVATE \ 43 | MAP_FIXED \ 44 | MAP_ANONYMOUS \ 45 | MAP_DENYWRITE \ 46 | MAP_EXECUTABLE \ 47 | MAP_UNINITIALIZED \ 48 | MAP_GROWSDOWN \ 49 | MAP_LOCKED \ 50 | MAP_NORESERVE \ 51 | MAP_POPULATE \ 52 | MAP_NONBLOCK \ 53 | MAP_STACK \ 54 | MAP_HUGETLB \ 55 | MAP_32BIT \ 56 | MAP_ABOVE4G \ 57 | MAP_HUGE_2MB \ 58 | MAP_HUGE_1GB) 59 60 extern int sysctl_overcommit_memory; 61 extern int sysctl_overcommit_ratio; 62 extern unsigned long sysctl_overcommit_kbytes; 63 extern struct percpu_counter vm_committed_as; 64 65 #ifdef CONFIG_SMP 66 extern s32 vm_committed_as_batch; 67 extern void mm_compute_batch(int overcommit_policy); 68 #else 69 #define vm_committed_as_batch 0 70 static inline void mm_compute_batch(int overcommit_policy) 71 { 72 } 73 #endif 74 75 unsigned long vm_memory_committed(void); 76 77 static inline void vm_acct_memory(long pages) 78 { 79 percpu_counter_add_batch(&vm_committed_as, pages, vm_committed_as_batch); 80 } 81 82 static inline void vm_unacct_memory(long pages) 83 { 84 vm_acct_memory(-pages); 85 } 86 87 /* 88 * Allow architectures to handle additional protection and flag bits. The 89 * overriding macros must be defined in the arch-specific asm/mman.h file. 90 */ 91 92 #ifndef arch_calc_vm_prot_bits 93 #define arch_calc_vm_prot_bits(prot, pkey) 0 94 #endif 95 96 #ifndef arch_calc_vm_flag_bits 97 #define arch_calc_vm_flag_bits(flags) 0 98 #endif 99 100 #ifndef arch_validate_prot 101 /* 102 * This is called from mprotect(). PROT_GROWSDOWN and PROT_GROWSUP have 103 * already been masked out. 104 * 105 * Returns true if the prot flags are valid 106 */ 107 static inline bool arch_validate_prot(unsigned long prot, unsigned long addr) 108 { 109 return (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) == 0; 110 } 111 #define arch_validate_prot arch_validate_prot 112 #endif 113 114 #ifndef arch_validate_flags 115 /* 116 * This is called from mmap() and mprotect() with the updated vma->vm_flags. 117 * 118 * Returns true if the VM_* flags are valid. 119 */ 120 static inline bool arch_validate_flags(unsigned long flags) 121 { 122 return true; 123 } 124 #define arch_validate_flags arch_validate_flags 125 #endif 126 127 /* 128 * Optimisation macro. It is equivalent to: 129 * (x & bit1) ? bit2 : 0 130 * but this version is faster. 131 * ("bit1" and "bit2" must be single bits) 132 */ 133 #define _calc_vm_trans(x, bit1, bit2) \ 134 ((!(bit1) || !(bit2)) ? 0 : \ 135 ((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \ 136 : ((x) & (bit1)) / ((bit1) / (bit2)))) 137 138 /* 139 * Combine the mmap "prot" argument into "vm_flags" used internally. 140 */ 141 static inline unsigned long 142 calc_vm_prot_bits(unsigned long prot, unsigned long pkey) 143 { 144 return _calc_vm_trans(prot, PROT_READ, VM_READ ) | 145 _calc_vm_trans(prot, PROT_WRITE, VM_WRITE) | 146 _calc_vm_trans(prot, PROT_EXEC, VM_EXEC) | 147 arch_calc_vm_prot_bits(prot, pkey); 148 } 149 150 /* 151 * Combine the mmap "flags" argument into "vm_flags" used internally. 152 */ 153 static inline unsigned long 154 calc_vm_flag_bits(unsigned long flags) 155 { 156 return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) | 157 _calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED ) | 158 _calc_vm_trans(flags, MAP_SYNC, VM_SYNC ) | 159 arch_calc_vm_flag_bits(flags); 160 } 161 162 unsigned long vm_commit_limit(void); 163 164 /* 165 * Denies creating a writable executable mapping or gaining executable permissions. 166 * 167 * This denies the following: 168 * 169 * a) mmap(PROT_WRITE | PROT_EXEC) 170 * 171 * b) mmap(PROT_WRITE) 172 * mprotect(PROT_EXEC) 173 * 174 * c) mmap(PROT_WRITE) 175 * mprotect(PROT_READ) 176 * mprotect(PROT_EXEC) 177 * 178 * But allows the following: 179 * 180 * d) mmap(PROT_READ | PROT_EXEC) 181 * mmap(PROT_READ | PROT_EXEC | PROT_BTI) 182 */ 183 static inline bool map_deny_write_exec(struct vm_area_struct *vma, unsigned long vm_flags) 184 { 185 if (!test_bit(MMF_HAS_MDWE, ¤t->mm->flags)) 186 return false; 187 188 if ((vm_flags & VM_EXEC) && (vm_flags & VM_WRITE)) 189 return true; 190 191 if (!(vma->vm_flags & VM_EXEC) && (vm_flags & VM_EXEC)) 192 return true; 193 194 return false; 195 } 196 197 #endif /* _LINUX_MMAN_H */ 198