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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_MMAN_H
#define _LINUX_MMAN_H
#include <linux/mm.h>
#include <linux/percpu_counter.h>
#include <linux/atomic.h>
#include <uapi/linux/mman.h>
/*
* Arrange for legacy / undefined architecture specific flags to be
* ignored by mmap handling code.
*/
#ifndef MAP_32BIT
#define MAP_32BIT 0
#endif
#ifndef MAP_ABOVE4G
#define MAP_ABOVE4G 0
#endif
#ifndef MAP_HUGE_2MB
#define MAP_HUGE_2MB 0
#endif
#ifndef MAP_HUGE_1GB
#define MAP_HUGE_1GB 0
#endif
#ifndef MAP_UNINITIALIZED
#define MAP_UNINITIALIZED 0
#endif
#ifndef MAP_SYNC
#define MAP_SYNC 0
#endif
/*
* The historical set of flags that all mmap implementations implicitly
* support when a ->mmap_validate() op is not provided in file_operations.
*
* MAP_EXECUTABLE and MAP_DENYWRITE are completely ignored throughout the
* kernel.
*/
#define LEGACY_MAP_MASK (MAP_SHARED \
| MAP_PRIVATE \
| MAP_FIXED \
| MAP_ANONYMOUS \
| MAP_DENYWRITE \
| MAP_EXECUTABLE \
| MAP_UNINITIALIZED \
| MAP_GROWSDOWN \
| MAP_LOCKED \
| MAP_NORESERVE \
| MAP_POPULATE \
| MAP_NONBLOCK \
| MAP_STACK \
| MAP_HUGETLB \
| MAP_32BIT \
| MAP_ABOVE4G \
| MAP_HUGE_2MB \
| MAP_HUGE_1GB)
extern int sysctl_overcommit_memory;
extern int sysctl_overcommit_ratio;
extern unsigned long sysctl_overcommit_kbytes;
extern struct percpu_counter vm_committed_as;
#ifdef CONFIG_SMP
extern s32 vm_committed_as_batch;
extern void mm_compute_batch(int overcommit_policy);
#else
#define vm_committed_as_batch 0
static inline void mm_compute_batch(int overcommit_policy)
{
}
#endif
unsigned long vm_memory_committed(void);
static inline void vm_acct_memory(long pages)
{
percpu_counter_add_batch(&vm_committed_as, pages, vm_committed_as_batch);
}
static inline void vm_unacct_memory(long pages)
{
vm_acct_memory(-pages);
}
/*
* Allow architectures to handle additional protection and flag bits. The
* overriding macros must be defined in the arch-specific asm/mman.h file.
*/
#ifndef arch_calc_vm_prot_bits
#define arch_calc_vm_prot_bits(prot, pkey) 0
#endif
#ifndef arch_calc_vm_flag_bits
#define arch_calc_vm_flag_bits(flags) 0
#endif
#ifndef arch_validate_prot
/*
* This is called from mprotect(). PROT_GROWSDOWN and PROT_GROWSUP have
* already been masked out.
*
* Returns true if the prot flags are valid
*/
static inline bool arch_validate_prot(unsigned long prot, unsigned long addr)
{
return (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) == 0;
}
#define arch_validate_prot arch_validate_prot
#endif
#ifndef arch_validate_flags
/*
* This is called from mmap() and mprotect() with the updated vma->vm_flags.
*
* Returns true if the VM_* flags are valid.
*/
static inline bool arch_validate_flags(unsigned long flags)
{
return true;
}
#define arch_validate_flags arch_validate_flags
#endif
/*
* Optimisation macro. It is equivalent to:
* (x & bit1) ? bit2 : 0
* but this version is faster.
* ("bit1" and "bit2" must be single bits)
*/
#define _calc_vm_trans(x, bit1, bit2) \
((!(bit1) || !(bit2)) ? 0 : \
((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \
: ((x) & (bit1)) / ((bit1) / (bit2))))
/*
* Combine the mmap "prot" argument into "vm_flags" used internally.
*/
static inline unsigned long
calc_vm_prot_bits(unsigned long prot, unsigned long pkey)
{
return _calc_vm_trans(prot, PROT_READ, VM_READ ) |
_calc_vm_trans(prot, PROT_WRITE, VM_WRITE) |
_calc_vm_trans(prot, PROT_EXEC, VM_EXEC) |
arch_calc_vm_prot_bits(prot, pkey);
}
/*
* Combine the mmap "flags" argument into "vm_flags" used internally.
*/
static inline unsigned long
calc_vm_flag_bits(unsigned long flags)
{
return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) |
_calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED ) |
_calc_vm_trans(flags, MAP_SYNC, VM_SYNC ) |
_calc_vm_trans(flags, MAP_STACK, VM_NOHUGEPAGE) |
arch_calc_vm_flag_bits(flags);
}
unsigned long vm_commit_limit(void);
/*
* Denies creating a writable executable mapping or gaining executable permissions.
*
* This denies the following:
*
* a) mmap(PROT_WRITE | PROT_EXEC)
*
* b) mmap(PROT_WRITE)
* mprotect(PROT_EXEC)
*
* c) mmap(PROT_WRITE)
* mprotect(PROT_READ)
* mprotect(PROT_EXEC)
*
* But allows the following:
*
* d) mmap(PROT_READ | PROT_EXEC)
* mmap(PROT_READ | PROT_EXEC | PROT_BTI)
*/
static inline bool map_deny_write_exec(struct vm_area_struct *vma, unsigned long vm_flags)
{
if (!test_bit(MMF_HAS_MDWE, ¤t->mm->flags))
return false;
if ((vm_flags & VM_EXEC) && (vm_flags & VM_WRITE))
return true;
if (!(vma->vm_flags & VM_EXEC) && (vm_flags & VM_EXEC))
return true;
return false;
}
#endif /* _LINUX_MMAN_H */
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