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
  16 #include <asm/atomic.h>
  17
  18 extern int sysctl_overcommit_memory;
  19 extern int sysctl_overcommit_ratio;
  20 extern atomic_long_t vm_committed_space;
  21
  22 #ifdef CONFIG_SMP
  23 extern void vm_acct_memory(long pages);
  24 #else
  25 static inline void vm_acct_memory(long pages)
  26 {
  27         atomic_long_add(pages, &vm_committed_space);
  28 }
  29 #endif
  30
  31 static inline void vm_unacct_memory(long pages)
  32 {
  33         vm_acct_memory(-pages);
  34 }
  35
  36 /*
  37  * Allow architectures to handle additional protection bits
  38  */
  39
  40 #ifndef arch_calc_vm_prot_bits
  41 #define arch_calc_vm_prot_bits(prot) 0
  42 #endif
  43
  44 #ifndef arch_vm_get_page_prot
  45 #define arch_vm_get_page_prot(vm_flags) __pgprot(0)
  46 #endif
  47
  48 #ifndef arch_validate_prot
  49 /*
  50  * This is called from mprotect().  PROT_GROWSDOWN and PROT_GROWSUP have
  51  * already been masked out.
  52  *
  53  * Returns true if the prot flags are valid
  54  */
  55 static inline int arch_validate_prot(unsigned long prot)
  56 {
  57         return (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) == 0;
  58 }
  59 #define arch_validate_prot arch_validate_prot
  60 #endif
  61
  62 /*
  63  * Optimisation macro.  It is equivalent to:
  64  *      (x & bit1) ? bit2 : 0
  65  * but this version is faster.
  66  * ("bit1" and "bit2" must be single bits)
  67  */
  68 #define _calc_vm_trans(x, bit1, bit2) \
  69   ((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \
  70    : ((x) & (bit1)) / ((bit1) / (bit2)))
  71
  72 /*
  73  * Combine the mmap "prot" argument into "vm_flags" used internally.
  74  */
  75 static inline unsigned long
  76 calc_vm_prot_bits(unsigned long prot)
  77 {
  78         return _calc_vm_trans(prot, PROT_READ,  VM_READ ) |
  79                _calc_vm_trans(prot, PROT_WRITE, VM_WRITE) |
  80                _calc_vm_trans(prot, PROT_EXEC,  VM_EXEC) |
  81                arch_calc_vm_prot_bits(prot);
  82 }
  83
  84 /*
  85  * Combine the mmap "flags" argument into "vm_flags" used internally.
  86  */
  87 static inline unsigned long
  88 calc_vm_flag_bits(unsigned long flags)
  89 {
  90         return _calc_vm_trans(flags, MAP_GROWSDOWN,  VM_GROWSDOWN ) |
  91                _calc_vm_trans(flags, MAP_DENYWRITE,  VM_DENYWRITE ) |
  92                _calc_vm_trans(flags, MAP_EXECUTABLE, VM_EXECUTABLE) |
  93                _calc_vm_trans(flags, MAP_LOCKED,     VM_LOCKED    );
  94 }
  95 #endif /* __KERNEL__ */
  96 #endif /* _LINUX_MMAN_H */