include/linux/mman.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_MMAN_H
   3 #define _LINUX_MMAN_H
   4
   5 #include <linux/mm.h>
   6 #include <linux/percpu_counter.h>
   7
   8 #include <linux/atomic.h>
   9 #include <uapi/linux/mman.h>
  10
  11 extern int sysctl_overcommit_memory;
  12 extern int sysctl_overcommit_ratio;
  13 extern unsigned long sysctl_overcommit_kbytes;
  14 extern struct percpu_counter vm_committed_as;
  15
  16 #ifdef CONFIG_SMP
  17 extern s32 vm_committed_as_batch;
  18 #else
  19 #define vm_committed_as_batch 0
  20 #endif
  21
  22 unsigned long vm_memory_committed(void);
  23
  24 static inline void vm_acct_memory(long pages)
  25 {
  26         percpu_counter_add_batch(&vm_committed_as, pages, vm_committed_as_batch);
  27 }
  28
  29 static inline void vm_unacct_memory(long pages)
  30 {
  31         vm_acct_memory(-pages);
  32 }
  33
  34 /*
  35  * Allow architectures to handle additional protection bits
  36  */
  37
  38 #ifndef arch_calc_vm_prot_bits
  39 #define arch_calc_vm_prot_bits(prot, pkey) 0
  40 #endif
  41
  42 #ifndef arch_vm_get_page_prot
  43 #define arch_vm_get_page_prot(vm_flags) __pgprot(0)
  44 #endif
  45
  46 #ifndef arch_validate_prot
  47 /*
  48  * This is called from mprotect().  PROT_GROWSDOWN and PROT_GROWSUP have
  49  * already been masked out.
  50  *
  51  * Returns true if the prot flags are valid
  52  */
  53 static inline bool arch_validate_prot(unsigned long prot)
  54 {
  55         return (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) == 0;
  56 }
  57 #define arch_validate_prot arch_validate_prot
  58 #endif
  59
  60 /*
  61  * Optimisation macro.  It is equivalent to:
  62  *      (x & bit1) ? bit2 : 0
  63  * but this version is faster.
  64  * ("bit1" and "bit2" must be single bits)
  65  */
  66 #define _calc_vm_trans(x, bit1, bit2) \
  67   ((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \
  68    : ((x) & (bit1)) / ((bit1) / (bit2)))
  69
  70 /*
  71  * Combine the mmap "prot" argument into "vm_flags" used internally.
  72  */
  73 static inline unsigned long
  74 calc_vm_prot_bits(unsigned long prot, unsigned long pkey)
  75 {
  76         return _calc_vm_trans(prot, PROT_READ,  VM_READ ) |
  77                _calc_vm_trans(prot, PROT_WRITE, VM_WRITE) |
  78                _calc_vm_trans(prot, PROT_EXEC,  VM_EXEC) |
  79                arch_calc_vm_prot_bits(prot, pkey);
  80 }
  81
  82 /*
  83  * Combine the mmap "flags" argument into "vm_flags" used internally.
  84  */
  85 static inline unsigned long
  86 calc_vm_flag_bits(unsigned long flags)
  87 {
  88         return _calc_vm_trans(flags, MAP_GROWSDOWN,  VM_GROWSDOWN ) |
  89                _calc_vm_trans(flags, MAP_DENYWRITE,  VM_DENYWRITE ) |
  90                _calc_vm_trans(flags, MAP_LOCKED,     VM_LOCKED    );
  91 }
  92
  93 unsigned long vm_commit_limit(void);
  94 #endif /* _LINUX_MMAN_H */