include/linux/mman.h

   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
  10 extern int sysctl_overcommit_memory;
  11 extern int sysctl_overcommit_ratio;
  12 extern struct percpu_counter vm_committed_as;
  13
  14 static inline void vm_acct_memory(long pages)
  15 {
  16         percpu_counter_add(&vm_committed_as, pages);
  17 }
  18
  19 static 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  */
  43 static 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  */
  63 static inline unsigned long
  64 calc_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  */
  75 static inline unsigned long
  76 calc_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 */