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 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
  55extern int sysctl_overcommit_memory;
  56extern int sysctl_overcommit_ratio;
  57extern unsigned long sysctl_overcommit_kbytes;
  58extern struct percpu_counter vm_committed_as;
  59
  60#ifdef CONFIG_SMP
  61extern s32 vm_committed_as_batch;
  62extern void mm_compute_batch(int overcommit_policy);
  63#else
  64#define vm_committed_as_batch 0
  65static inline void mm_compute_batch(int overcommit_policy)
  66{
  67}
  68#endif
  69
  70unsigned long vm_memory_committed(void);
  71
  72static inline void vm_acct_memory(long pages)
  73{
  74        percpu_counter_add_batch(&vm_committed_as, pages, vm_committed_as_batch);
  75}
  76
  77static 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 */
 106static 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 */
 119static 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 */
 140static inline unsigned long
 141calc_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 */
 152static inline unsigned long
 153calc_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
 162unsigned long vm_commit_limit(void);
 163#endif /* _LINUX_MMAN_H */
 164