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 #ifdef CONFIG_SMP
  15 extern s32 vm_committed_as_batch;
  16 #else
  17 #define vm_committed_as_batch 0
  18 #endif
  19
  20 unsigned long vm_memory_committed(void);
  21
  22 static inline void vm_acct_memory(long pages)
  23 {
  24         __percpu_counter_add(&vm_committed_as, pages, vm_committed_as_batch);
  25 }
  26
  27 static inline void vm_unacct_memory(long pages)
  28 {
  29         vm_acct_memory(-pages);
  30 }
  31
  32 /*
  33  * Allow architectures to handle additional protection bits
  34  */
  35
  36 #ifndef arch_calc_vm_prot_bits
  37 #define arch_calc_vm_prot_bits(prot) 0
  38 #endif
  39
  40 #ifndef arch_vm_get_page_prot
  41 #define arch_vm_get_page_prot(vm_flags) __pgprot(0)
  42 #endif
  43
  44 #ifndef arch_validate_prot
  45 /*
  46  * This is called from mprotect().  PROT_GROWSDOWN and PROT_GROWSUP have
  47  * already been masked out.
  48  *
  49  * Returns true if the prot flags are valid
  50  */
  51 static inline int arch_validate_prot(unsigned long prot)
  52 {
  53         return (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) == 0;
  54 }
  55 #define arch_validate_prot arch_validate_prot
  56 #endif
  57
  58 /*
  59  * Optimisation macro.  It is equivalent to:
  60  *      (x & bit1) ? bit2 : 0
  61  * but this version is faster.
  62  * ("bit1" and "bit2" must be single bits)
  63  */
  64 #define _calc_vm_trans(x, bit1, bit2) \
  65   ((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \
  66    : ((x) & (bit1)) / ((bit1) / (bit2)))
  67
  68 /*
  69  * Combine the mmap "prot" argument into "vm_flags" used internally.
  70  */
  71 static inline unsigned long
  72 calc_vm_prot_bits(unsigned long prot)
  73 {
  74         return _calc_vm_trans(prot, PROT_READ,  VM_READ ) |
  75                _calc_vm_trans(prot, PROT_WRITE, VM_WRITE) |
  76                _calc_vm_trans(prot, PROT_EXEC,  VM_EXEC) |
  77                arch_calc_vm_prot_bits(prot);
  78 }
  79
  80 /*
  81  * Combine the mmap "flags" argument into "vm_flags" used internally.
  82  */
  83 static inline unsigned long
  84 calc_vm_flag_bits(unsigned long flags)
  85 {
  86         return _calc_vm_trans(flags, MAP_GROWSDOWN,  VM_GROWSDOWN ) |
  87                _calc_vm_trans(flags, MAP_DENYWRITE,  VM_DENYWRITE ) |
  88                _calc_vm_trans(flags, MAP_LOCKED,     VM_LOCKED    );
  89 }
  90 #endif /* _LINUX_MMAN_H */