include/linux/mman.h

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002 #ifndef _LINUX_MMAN_H
0003 #define _LINUX_MMAN_H
0004
0005 #include <linux/mm.h>
0006 #include <linux/percpu_counter.h>
0007
0008 #include <linux/atomic.h>
0009 #include <uapi/linux/mman.h>
0010
0011 /*
0012  * Arrange for legacy / undefined architecture specific flags to be
0013  * ignored by mmap handling code.
0014  */
0015 #ifndef MAP_32BIT
0016 #define MAP_32BIT 0
0017 #endif
0018 #ifndef MAP_HUGE_2MB
0019 #define MAP_HUGE_2MB 0
0020 #endif
0021 #ifndef MAP_HUGE_1GB
0022 #define MAP_HUGE_1GB 0
0023 #endif
0024 #ifndef MAP_UNINITIALIZED
0025 #define MAP_UNINITIALIZED 0
0026 #endif
0027 #ifndef MAP_SYNC
0028 #define MAP_SYNC 0
0029 #endif
0030
0031 /*
0032  * The historical set of flags that all mmap implementations implicitly
0033  * support when a ->mmap_validate() op is not provided in file_operations.
0034  *
0035  * MAP_EXECUTABLE and MAP_DENYWRITE are completely ignored throughout the
0036  * kernel.
0037  */
0038 #define LEGACY_MAP_MASK (MAP_SHARED \
0039         | MAP_PRIVATE \
0040         | MAP_FIXED \
0041         | MAP_ANONYMOUS \
0042         | MAP_DENYWRITE \
0043         | MAP_EXECUTABLE \
0044         | MAP_UNINITIALIZED \
0045         | MAP_GROWSDOWN \
0046         | MAP_LOCKED \
0047         | MAP_NORESERVE \
0048         | MAP_POPULATE \
0049         | MAP_NONBLOCK \
0050         | MAP_STACK \
0051         | MAP_HUGETLB \
0052         | MAP_32BIT \
0053         | MAP_HUGE_2MB \
0054         | MAP_HUGE_1GB)
0055
0056 extern int sysctl_overcommit_memory;
0057 extern int sysctl_overcommit_ratio;
0058 extern unsigned long sysctl_overcommit_kbytes;
0059 extern struct percpu_counter vm_committed_as;
0060
0061 #ifdef CONFIG_SMP
0062 extern s32 vm_committed_as_batch;
0063 extern void mm_compute_batch(int overcommit_policy);
0064 #else
0065 #define vm_committed_as_batch 0
0066 static inline void mm_compute_batch(int overcommit_policy)
0067 {
0068 }
0069 #endif
0070
0071 unsigned long vm_memory_committed(void);
0072
0073 static inline void vm_acct_memory(long pages)
0074 {
0075     percpu_counter_add_batch(&vm_committed_as, pages, vm_committed_as_batch);
0076 }
0077
0078 static inline void vm_unacct_memory(long pages)
0079 {
0080     vm_acct_memory(-pages);
0081 }
0082
0083 /*
0084  * Allow architectures to handle additional protection and flag bits. The
0085  * overriding macros must be defined in the arch-specific asm/mman.h file.
0086  */
0087
0088 #ifndef arch_calc_vm_prot_bits
0089 #define arch_calc_vm_prot_bits(prot, pkey) 0
0090 #endif
0091
0092 #ifndef arch_calc_vm_flag_bits
0093 #define arch_calc_vm_flag_bits(flags) 0
0094 #endif
0095
0096 #ifndef arch_validate_prot
0097 /*
0098  * This is called from mprotect().  PROT_GROWSDOWN and PROT_GROWSUP have
0099  * already been masked out.
0100  *
0101  * Returns true if the prot flags are valid
0102  */
0103 static inline bool arch_validate_prot(unsigned long prot, unsigned long addr)
0104 {
0105     return (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) == 0;
0106 }
0107 #define arch_validate_prot arch_validate_prot
0108 #endif
0109
0110 #ifndef arch_validate_flags
0111 /*
0112  * This is called from mmap() and mprotect() with the updated vma->vm_flags.
0113  *
0114  * Returns true if the VM_* flags are valid.
0115  */
0116 static inline bool arch_validate_flags(unsigned long flags)
0117 {
0118     return true;
0119 }
0120 #define arch_validate_flags arch_validate_flags
0121 #endif
0122
0123 /*
0124  * Optimisation macro.  It is equivalent to:
0125  *      (x & bit1) ? bit2 : 0
0126  * but this version is faster.
0127  * ("bit1" and "bit2" must be single bits)
0128  */
0129 #define _calc_vm_trans(x, bit1, bit2) \
0130   ((!(bit1) || !(bit2)) ? 0 : \
0131   ((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \
0132    : ((x) & (bit1)) / ((bit1) / (bit2))))
0133
0134 /*
0135  * Combine the mmap "prot" argument into "vm_flags" used internally.
0136  */
0137 static inline unsigned long
0138 calc_vm_prot_bits(unsigned long prot, unsigned long pkey)
0139 {
0140     return _calc_vm_trans(prot, PROT_READ,  VM_READ ) |
0141            _calc_vm_trans(prot, PROT_WRITE, VM_WRITE) |
0142            _calc_vm_trans(prot, PROT_EXEC,  VM_EXEC) |
0143            arch_calc_vm_prot_bits(prot, pkey);
0144 }
0145
0146 /*
0147  * Combine the mmap "flags" argument into "vm_flags" used internally.
0148  */
0149 static inline unsigned long
0150 calc_vm_flag_bits(unsigned long flags)
0151 {
0152     return _calc_vm_trans(flags, MAP_GROWSDOWN,  VM_GROWSDOWN ) |
0153            _calc_vm_trans(flags, MAP_LOCKED,     VM_LOCKED    ) |
0154            _calc_vm_trans(flags, MAP_SYNC,       VM_SYNC      ) |
0155            arch_calc_vm_flag_bits(flags);
0156 }
0157
0158 unsigned long vm_commit_limit(void);
0159 #endif /* _LINUX_MMAN_H */