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 unsigned long vm_memory_committed(void);
  15
  16 static inline void vm_acct_memory(long pages)
  17 {
  18         percpu_counter_add(&vm_committed_as, pages);
  19 }
  20
  21 static 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  */
  45 static 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  */
  65 static inline unsigned long
  66 calc_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  */
  77 static inline unsigned long
  78 calc_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 */