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
  14unsigned long vm_memory_committed(void);
  15
  16static inline void vm_acct_memory(long pages)
  17{
  18        percpu_counter_add(&vm_committed_as, pages);
  19}
  20
  21static inline void vm_unacct_memory(long pages)
  22{
  23        vm_acct_memory(-pages);
  24}
  25
  26/*
  27 * Allow architectures to handle additional protection bits
  28 */
  29
  30#ifndef arch_calc_vm_prot_bits
  31#define arch_calc_vm_prot_bits(prot) 0
  32#endif
  33
  34#ifndef arch_vm_get_page_prot
  35#define arch_vm_get_page_prot(vm_flags) __pgprot(0)
  36#endif
  37
  38#ifndef arch_validate_prot
  39/*
  40 * This is called from mprotect().  PROT_GROWSDOWN and PROT_GROWSUP have
  41 * already been masked out.
  42 *
  43 * Returns true if the prot flags are valid
  44 */
  45static inline int arch_validate_prot(unsigned long prot)
  46{
  47        return (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) == 0;
  48}
  49#define arch_validate_prot arch_validate_prot
  50#endif
  51
  52/*
  53 * Optimisation macro.  It is equivalent to:
  54 *      (x & bit1) ? bit2 : 0
  55 * but this version is faster.
  56 * ("bit1" and "bit2" must be single bits)
  57 */
  58#define _calc_vm_trans(x, bit1, bit2) \
  59  ((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \
  60   : ((x) & (bit1)) / ((bit1) / (bit2)))
  61
  62/*
  63 * Combine the mmap "prot" argument into "vm_flags" used internally.
  64 */
  65static inline unsigned long
  66calc_vm_prot_bits(unsigned long prot)
  67{
  68        return _calc_vm_trans(prot, PROT_READ,  VM_READ ) |
  69               _calc_vm_trans(prot, PROT_WRITE, VM_WRITE) |
  70               _calc_vm_trans(prot, PROT_EXEC,  VM_EXEC) |
  71               arch_calc_vm_prot_bits(prot);
  72}
  73
  74/*
  75 * Combine the mmap "flags" argument into "vm_flags" used internally.
  76 */
  77static inline unsigned long
  78calc_vm_flag_bits(unsigned long flags)
  79{
  80        return _calc_vm_trans(flags, MAP_GROWSDOWN,  VM_GROWSDOWN ) |
  81               _calc_vm_trans(flags, MAP_DENYWRITE,  VM_DENYWRITE ) |
  82               _calc_vm_trans(flags, MAP_LOCKED,     VM_LOCKED    );
  83}
  84#endif /* _LINUX_MMAN_H */
  85
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