194 строки
4.5 KiB
C
194 строки
4.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_MMAN_H
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#define _LINUX_MMAN_H
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#include <linux/mm.h>
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#include <linux/percpu_counter.h>
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#include <linux/atomic.h>
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#include <uapi/linux/mman.h>
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/*
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* Arrange for legacy / undefined architecture specific flags to be
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* ignored by mmap handling code.
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*/
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#ifndef MAP_32BIT
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#define MAP_32BIT 0
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#endif
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#ifndef MAP_HUGE_2MB
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#define MAP_HUGE_2MB 0
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#endif
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#ifndef MAP_HUGE_1GB
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#define MAP_HUGE_1GB 0
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#endif
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#ifndef MAP_UNINITIALIZED
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#define MAP_UNINITIALIZED 0
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#endif
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#ifndef MAP_SYNC
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#define MAP_SYNC 0
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#endif
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/*
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* The historical set of flags that all mmap implementations implicitly
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* support when a ->mmap_validate() op is not provided in file_operations.
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*
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* MAP_EXECUTABLE and MAP_DENYWRITE are completely ignored throughout the
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* kernel.
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*/
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#define LEGACY_MAP_MASK (MAP_SHARED \
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| MAP_PRIVATE \
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| MAP_FIXED \
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| MAP_ANONYMOUS \
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| MAP_DENYWRITE \
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| MAP_EXECUTABLE \
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| MAP_UNINITIALIZED \
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| MAP_GROWSDOWN \
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| MAP_LOCKED \
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| MAP_NORESERVE \
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| MAP_POPULATE \
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| MAP_NONBLOCK \
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| MAP_STACK \
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| MAP_HUGETLB \
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| MAP_32BIT \
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| MAP_HUGE_2MB \
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| MAP_HUGE_1GB)
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extern int sysctl_overcommit_memory;
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extern int sysctl_overcommit_ratio;
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extern unsigned long sysctl_overcommit_kbytes;
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extern struct percpu_counter vm_committed_as;
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#ifdef CONFIG_SMP
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extern s32 vm_committed_as_batch;
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extern void mm_compute_batch(int overcommit_policy);
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#else
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#define vm_committed_as_batch 0
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static inline void mm_compute_batch(int overcommit_policy)
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{
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}
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#endif
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unsigned long vm_memory_committed(void);
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static inline void vm_acct_memory(long pages)
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{
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percpu_counter_add_batch(&vm_committed_as, pages, vm_committed_as_batch);
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}
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static inline void vm_unacct_memory(long pages)
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{
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vm_acct_memory(-pages);
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}
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/*
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* Allow architectures to handle additional protection and flag bits. The
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* overriding macros must be defined in the arch-specific asm/mman.h file.
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*/
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#ifndef arch_calc_vm_prot_bits
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#define arch_calc_vm_prot_bits(prot, pkey) 0
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#endif
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#ifndef arch_calc_vm_flag_bits
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#define arch_calc_vm_flag_bits(flags) 0
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#endif
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#ifndef arch_validate_prot
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/*
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* This is called from mprotect(). PROT_GROWSDOWN and PROT_GROWSUP have
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* already been masked out.
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*
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* Returns true if the prot flags are valid
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*/
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static inline bool arch_validate_prot(unsigned long prot, unsigned long addr)
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{
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return (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) == 0;
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}
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#define arch_validate_prot arch_validate_prot
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#endif
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#ifndef arch_validate_flags
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/*
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* This is called from mmap() and mprotect() with the updated vma->vm_flags.
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*
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* Returns true if the VM_* flags are valid.
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*/
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static inline bool arch_validate_flags(unsigned long flags)
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{
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return true;
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}
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#define arch_validate_flags arch_validate_flags
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#endif
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/*
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* Optimisation macro. It is equivalent to:
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* (x & bit1) ? bit2 : 0
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* but this version is faster.
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* ("bit1" and "bit2" must be single bits)
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*/
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#define _calc_vm_trans(x, bit1, bit2) \
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((!(bit1) || !(bit2)) ? 0 : \
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((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \
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: ((x) & (bit1)) / ((bit1) / (bit2))))
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/*
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* Combine the mmap "prot" argument into "vm_flags" used internally.
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*/
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static inline unsigned long
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calc_vm_prot_bits(unsigned long prot, unsigned long pkey)
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{
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return _calc_vm_trans(prot, PROT_READ, VM_READ ) |
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_calc_vm_trans(prot, PROT_WRITE, VM_WRITE) |
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_calc_vm_trans(prot, PROT_EXEC, VM_EXEC) |
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arch_calc_vm_prot_bits(prot, pkey);
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}
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/*
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* Combine the mmap "flags" argument into "vm_flags" used internally.
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*/
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static inline unsigned long
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calc_vm_flag_bits(unsigned long flags)
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{
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return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) |
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_calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED ) |
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_calc_vm_trans(flags, MAP_SYNC, VM_SYNC ) |
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arch_calc_vm_flag_bits(flags);
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}
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unsigned long vm_commit_limit(void);
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/*
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* Denies creating a writable executable mapping or gaining executable permissions.
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*
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* This denies the following:
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*
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* a) mmap(PROT_WRITE | PROT_EXEC)
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*
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* b) mmap(PROT_WRITE)
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* mprotect(PROT_EXEC)
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*
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* c) mmap(PROT_WRITE)
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* mprotect(PROT_READ)
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* mprotect(PROT_EXEC)
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*
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* But allows the following:
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*
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* d) mmap(PROT_READ | PROT_EXEC)
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* mmap(PROT_READ | PROT_EXEC | PROT_BTI)
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*/
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static inline bool map_deny_write_exec(struct vm_area_struct *vma, unsigned long vm_flags)
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{
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if (!test_bit(MMF_HAS_MDWE, ¤t->mm->flags))
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return false;
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if ((vm_flags & VM_EXEC) && (vm_flags & VM_WRITE))
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return true;
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if (!(vma->vm_flags & VM_EXEC) && (vm_flags & VM_EXEC))
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return true;
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return false;
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}
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#endif /* _LINUX_MMAN_H */
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