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