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#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
  53extern int sysctl_overcommit_memory;
  54extern int sysctl_overcommit_ratio;
  55extern unsigned long sysctl_overcommit_kbytes;
  56extern struct percpu_counter vm_committed_as;
  57
  58#ifdef CONFIG_SMP
  59extern s32 vm_committed_as_batch;
  60extern void mm_compute_batch(int overcommit_policy);
  61#else
  62#define vm_committed_as_batch 0
  63static inline void mm_compute_batch(int overcommit_policy)
  64{
  65}
  66#endif
  67
  68unsigned long vm_memory_committed(void);
  69
  70static inline void vm_acct_memory(long pages)
  71{
  72        percpu_counter_add_batch(&vm_committed_as, pages, vm_committed_as_batch);
  73}
  74
  75static inline void vm_unacct_memory(long pages)
  76{
  77        vm_acct_memory(-pages);
  78}
  79
  80/*
  81 * Allow architectures to handle additional protection and flag bits. The
  82 * overriding macros must be defined in the arch-specific asm/mman.h file.
  83 */
  84
  85#ifndef arch_calc_vm_prot_bits
  86#define arch_calc_vm_prot_bits(prot, pkey) 0
  87#endif
  88
  89#ifndef arch_calc_vm_flag_bits
  90#define arch_calc_vm_flag_bits(flags) 0
  91#endif
  92
  93#ifndef arch_vm_get_page_prot
  94#define arch_vm_get_page_prot(vm_flags) __pgprot(0)
  95#endif
  96
  97#ifndef arch_validate_prot
  98/*
  99 * This is called from mprotect().  PROT_GROWSDOWN and PROT_GROWSUP have
 100 * already been masked out.
 101 *
 102 * Returns true if the prot flags are valid
 103 */
 104static inline bool arch_validate_prot(unsigned long prot, unsigned long addr)
 105{
 106        return (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) == 0;
 107}
 108#define arch_validate_prot arch_validate_prot
 109#endif
 110
 111#ifndef arch_validate_flags
 112/*
 113 * This is called from mmap() and mprotect() with the updated vma->vm_flags.
 114 *
 115 * Returns true if the VM_* flags are valid.
 116 */
 117static inline bool arch_validate_flags(unsigned long flags)
 118{
 119        return true;
 120}
 121#define arch_validate_flags arch_validate_flags
 122#endif
 123
 124/*
 125 * Optimisation macro.  It is equivalent to:
 126 *      (x & bit1) ? bit2 : 0
 127 * but this version is faster.
 128 * ("bit1" and "bit2" must be single bits)
 129 */
 130#define _calc_vm_trans(x, bit1, bit2) \
 131  ((!(bit1) || !(bit2)) ? 0 : \
 132  ((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \
 133   : ((x) & (bit1)) / ((bit1) / (bit2))))
 134
 135/*
 136 * Combine the mmap "prot" argument into "vm_flags" used internally.
 137 */
 138static inline unsigned long
 139calc_vm_prot_bits(unsigned long prot, unsigned long pkey)
 140{
 141        return _calc_vm_trans(prot, PROT_READ,  VM_READ ) |
 142               _calc_vm_trans(prot, PROT_WRITE, VM_WRITE) |
 143               _calc_vm_trans(prot, PROT_EXEC,  VM_EXEC) |
 144               arch_calc_vm_prot_bits(prot, pkey);
 145}
 146
 147/*
 148 * Combine the mmap "flags" argument into "vm_flags" used internally.
 149 */
 150static inline unsigned long
 151calc_vm_flag_bits(unsigned long flags)
 152{
 153        return _calc_vm_trans(flags, MAP_GROWSDOWN,  VM_GROWSDOWN ) |
 154               _calc_vm_trans(flags, MAP_DENYWRITE,  VM_DENYWRITE ) |
 155               _calc_vm_trans(flags, MAP_LOCKED,     VM_LOCKED    ) |
 156               _calc_vm_trans(flags, MAP_SYNC,       VM_SYNC      ) |
 157               arch_calc_vm_flag_bits(flags);
 158}
 159
 160unsigned long vm_commit_limit(void);
 161#endif /* _LINUX_MMAN_H */
 162