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 60extern int sysctl_overcommit_memory; 61extern int sysctl_overcommit_ratio; 62extern unsigned long sysctl_overcommit_kbytes; 63extern struct percpu_counter vm_committed_as; 64 65#ifdef CONFIG_SMP 66extern s32 vm_committed_as_batch; 67extern void mm_compute_batch(int overcommit_policy); 68#else 69#define vm_committed_as_batch 0 70static inline void mm_compute_batch(int overcommit_policy) 71{ 72} 73#endif 74 75unsigned long vm_memory_committed(void); 76 77static inline void vm_acct_memory(long pages) 78{ 79 percpu_counter_add_batch(&vm_committed_as, pages, vm_committed_as_batch); 80} 81 82static 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 */ 107static 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 */ 120static 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 */ 141static inline unsigned long 142calc_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 */ 153static inline unsigned long 154calc_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 _calc_vm_trans(flags, MAP_STACK, VM_NOHUGEPAGE) | 160 arch_calc_vm_flag_bits(flags); 161} 162 163unsigned long vm_commit_limit(void); 164 165#ifndef arch_memory_deny_write_exec_supported 166static inline bool arch_memory_deny_write_exec_supported(void) 167{ 168 return true; 169} 170#define arch_memory_deny_write_exec_supported arch_memory_deny_write_exec_supported 171#endif 172 173/* 174 * Denies creating a writable executable mapping or gaining executable permissions. 175 * 176 * This denies the following: 177 * 178 * a) mmap(PROT_WRITE | PROT_EXEC) 179 * 180 * b) mmap(PROT_WRITE) 181 * mprotect(PROT_EXEC) 182 * 183 * c) mmap(PROT_WRITE) 184 * mprotect(PROT_READ) 185 * mprotect(PROT_EXEC) 186 * 187 * But allows the following: 188 * 189 * d) mmap(PROT_READ | PROT_EXEC) 190 * mmap(PROT_READ | PROT_EXEC | PROT_BTI) 191 */ 192static inline bool map_deny_write_exec(struct vm_area_struct *vma, unsigned long vm_flags) 193{ 194 if (!test_bit(MMF_HAS_MDWE, ¤t->mm->flags)) 195 return false; 196 197 if ((vm_flags & VM_EXEC) && (vm_flags & VM_WRITE)) 198 return true; 199 200 if (!(vma->vm_flags & VM_EXEC) && (vm_flags & VM_EXEC)) 201 return true; 202 203 return false; 204} 205 206#endif /* _LINUX_MMAN_H */ 207