linux/include/linux/mman.h
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   1#ifndef _LINUX_MMAN_H
   2#define _LINUX_MMAN_H
   3
   4#include <linux/mm.h>
   5#include <linux/percpu_counter.h>
   6
   7#include <linux/atomic.h>
   8#include <uapi/linux/mman.h>
   9
  10extern int sysctl_overcommit_memory;
  11extern int sysctl_overcommit_ratio;
  12extern struct percpu_counter vm_committed_as;
  13
  14static inline void vm_acct_memory(long pages)
  15{
  16        percpu_counter_add(&vm_committed_as, pages);
  17}
  18
  19static inline void vm_unacct_memory(long pages)
  20{
  21        vm_acct_memory(-pages);
  22}
  23
  24/*
  25 * Allow architectures to handle additional protection bits
  26 */
  27
  28#ifndef arch_calc_vm_prot_bits
  29#define arch_calc_vm_prot_bits(prot) 0
  30#endif
  31
  32#ifndef arch_vm_get_page_prot
  33#define arch_vm_get_page_prot(vm_flags) __pgprot(0)
  34#endif
  35
  36#ifndef arch_validate_prot
  37/*
  38 * This is called from mprotect().  PROT_GROWSDOWN and PROT_GROWSUP have
  39 * already been masked out.
  40 *
  41 * Returns true if the prot flags are valid
  42 */
  43static inline int arch_validate_prot(unsigned long prot)
  44{
  45        return (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) == 0;
  46}
  47#define arch_validate_prot arch_validate_prot
  48#endif
  49
  50/*
  51 * Optimisation macro.  It is equivalent to:
  52 *      (x & bit1) ? bit2 : 0
  53 * but this version is faster.
  54 * ("bit1" and "bit2" must be single bits)
  55 */
  56#define _calc_vm_trans(x, bit1, bit2) \
  57  ((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \
  58   : ((x) & (bit1)) / ((bit1) / (bit2)))
  59
  60/*
  61 * Combine the mmap "prot" argument into "vm_flags" used internally.
  62 */
  63static inline unsigned long
  64calc_vm_prot_bits(unsigned long prot)
  65{
  66        return _calc_vm_trans(prot, PROT_READ,  VM_READ ) |
  67               _calc_vm_trans(prot, PROT_WRITE, VM_WRITE) |
  68               _calc_vm_trans(prot, PROT_EXEC,  VM_EXEC) |
  69               arch_calc_vm_prot_bits(prot);
  70}
  71
  72/*
  73 * Combine the mmap "flags" argument into "vm_flags" used internally.
  74 */
  75static inline unsigned long
  76calc_vm_flag_bits(unsigned long flags)
  77{
  78        return _calc_vm_trans(flags, MAP_GROWSDOWN,  VM_GROWSDOWN ) |
  79               _calc_vm_trans(flags, MAP_DENYWRITE,  VM_DENYWRITE ) |
  80               _calc_vm_trans(flags, MAP_LOCKED,     VM_LOCKED    );
  81}
  82#endif /* _LINUX_MMAN_H */
  83
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