include/linux/mman.h

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