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 #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
  63 static inline void mm_compute_batch(int overcommit_policy)
  64 {
  65 }
  66 #endif
  67
  68 unsigned long vm_memory_committed(void);
  69
  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
  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 bits
  82  */
  83
  84 #ifndef arch_calc_vm_prot_bits
  85 #define arch_calc_vm_prot_bits(prot, pkey) 0
  86 #endif
  87
  88 #ifndef arch_vm_get_page_prot
  89 #define arch_vm_get_page_prot(vm_flags) __pgprot(0)
  90 #endif
  91
  92 #ifndef arch_validate_prot
  93 /*
  94  * This is called from mprotect().  PROT_GROWSDOWN and PROT_GROWSUP have
  95  * already been masked out.
  96  *
  97  * Returns true if the prot flags are valid
  98  */
  99 static inline bool arch_validate_prot(unsigned long prot, unsigned long addr)
 100 {
 101         return (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) == 0;
 102 }
 103 #define arch_validate_prot arch_validate_prot
 104 #endif
 105
 106 /*
 107  * Optimisation macro.  It is equivalent to:
 108  *      (x & bit1) ? bit2 : 0
 109  * but this version is faster.
 110  * ("bit1" and "bit2" must be single bits)
 111  */
 112 #define _calc_vm_trans(x, bit1, bit2) \
 113   ((!(bit1) || !(bit2)) ? 0 : \
 114   ((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \
 115    : ((x) & (bit1)) / ((bit1) / (bit2))))
 116
 117 /*
 118  * Combine the mmap "prot" argument into "vm_flags" used internally.
 119  */
 120 static inline unsigned long
 121 calc_vm_prot_bits(unsigned long prot, unsigned long pkey)
 122 {
 123         return _calc_vm_trans(prot, PROT_READ,  VM_READ ) |
 124                _calc_vm_trans(prot, PROT_WRITE, VM_WRITE) |
 125                _calc_vm_trans(prot, PROT_EXEC,  VM_EXEC) |
 126                arch_calc_vm_prot_bits(prot, pkey);
 127 }
 128
 129 /*
 130  * Combine the mmap "flags" argument into "vm_flags" used internally.
 131  */
 132 static inline unsigned long
 133 calc_vm_flag_bits(unsigned long flags)
 134 {
 135         return _calc_vm_trans(flags, MAP_GROWSDOWN,  VM_GROWSDOWN ) |
 136                _calc_vm_trans(flags, MAP_DENYWRITE,  VM_DENYWRITE ) |
 137                _calc_vm_trans(flags, MAP_LOCKED,     VM_LOCKED    ) |
 138                _calc_vm_trans(flags, MAP_SYNC,       VM_SYNC      );
 139 }
 140
 141 unsigned long vm_commit_limit(void);
 142 #endif /* _LINUX_MMAN_H */