include/linux/mman.h

   1 #ifndef _LINUX_MMAN_H
   2 #define _LINUX_MMAN_H
   3
   4 #include <asm/mman.h>
   5
   6 #define MREMAP_MAYMOVE  1
   7 #define MREMAP_FIXED    2
   8
   9 #define OVERCOMMIT_GUESS                0
  10 #define OVERCOMMIT_ALWAYS               1
  11 #define OVERCOMMIT_NEVER                2
  12
  13 #ifdef __KERNEL__
  14 #include <linux/mm.h>
  15 #include <linux/percpu_counter.h>
  16
  17 #include <linux/atomic.h>
  18
  19 extern int sysctl_overcommit_memory;
  20 extern int sysctl_overcommit_ratio;
  21 extern struct percpu_counter vm_committed_as;
  22
  23 static inline void vm_acct_memory(long pages)
  24 {
  25         percpu_counter_add(&vm_committed_as, pages);
  26 }
  27
  28 static inline void vm_unacct_memory(long pages)
  29 {
  30         vm_acct_memory(-pages);
  31 }
  32
  33 /*
  34  * Allow architectures to handle additional protection bits
  35  */
  36
  37 #ifndef arch_calc_vm_prot_bits
  38 #define arch_calc_vm_prot_bits(prot) 0
  39 #endif
  40
  41 #ifndef arch_vm_get_page_prot
  42 #define arch_vm_get_page_prot(vm_flags) __pgprot(0)
  43 #endif
  44
  45 #ifndef arch_validate_prot
  46 /*
  47  * This is called from mprotect().  PROT_GROWSDOWN and PROT_GROWSUP have
  48  * already been masked out.
  49  *
  50  * Returns true if the prot flags are valid
  51  */
  52 static inline int arch_validate_prot(unsigned long prot)
  53 {
  54         return (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) == 0;
  55 }
  56 #define arch_validate_prot arch_validate_prot
  57 #endif
  58
  59 /*
  60  * Optimisation macro.  It is equivalent to:
  61  *      (x & bit1) ? bit2 : 0
  62  * but this version is faster.
  63  * ("bit1" and "bit2" must be single bits)
  64  */
  65 #define _calc_vm_trans(x, bit1, bit2) \
  66   ((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \
  67    : ((x) & (bit1)) / ((bit1) / (bit2)))
  68
  69 /*
  70  * Combine the mmap "prot" argument into "vm_flags" used internally.
  71  */
  72 static inline unsigned long
  73 calc_vm_prot_bits(unsigned long prot)
  74 {
  75         return _calc_vm_trans(prot, PROT_READ,  VM_READ ) |
  76                _calc_vm_trans(prot, PROT_WRITE, VM_WRITE) |
  77                _calc_vm_trans(prot, PROT_EXEC,  VM_EXEC) |
  78                arch_calc_vm_prot_bits(prot);
  79 }
  80
  81 /*
  82  * Combine the mmap "flags" argument into "vm_flags" used internally.
  83  */
  84 static inline unsigned long
  85 calc_vm_flag_bits(unsigned long flags)
  86 {
  87         return _calc_vm_trans(flags, MAP_GROWSDOWN,  VM_GROWSDOWN ) |
  88                _calc_vm_trans(flags, MAP_DENYWRITE,  VM_DENYWRITE ) |
  89                _calc_vm_trans(flags, MAP_EXECUTABLE, VM_EXECUTABLE) |
  90                _calc_vm_trans(flags, MAP_LOCKED,     VM_LOCKED    );
  91 }
  92 #endif /* __KERNEL__ */
  93 #endif /* _LINUX_MMAN_H */