linux/include/linux/mman.h

/* 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 …
#endif
#ifndef MAP_ABOVE4G
#define MAP_ABOVE4G …
#endif
#ifndef MAP_HUGE_2MB
#define MAP_HUGE_2MB …
#endif
#ifndef MAP_HUGE_1GB
#define MAP_HUGE_1GB …
#endif
#ifndef MAP_UNINITIALIZED
#define MAP_UNINITIALIZED …
#endif
#ifndef MAP_SYNC
#define MAP_SYNC …
#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 …

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 …
static inline void mm_compute_batch(int overcommit_policy)
{
}
#endif

unsigned long vm_memory_committed(void);

static inline void vm_acct_memory(long pages)
{ … }

static inline void vm_unacct_memory(long 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 …
#endif

#ifndef arch_calc_vm_flag_bits
#define arch_calc_vm_flag_bits(flags) …
#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)
{ … }
#define 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)
{ … }
#define 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) …

/*
 * Combine the mmap "prot" argument into "vm_flags" used internally.
 */
static inline unsigned long
calc_vm_prot_bits(unsigned long prot, unsigned long pkey)
{ … }

/*
 * Combine the mmap "flags" argument into "vm_flags" used internally.
 */
static inline unsigned long
calc_vm_flag_bits(unsigned long flags)
{ … }

unsigned long vm_commit_limit(void);

#ifndef arch_memory_deny_write_exec_supported
static inline bool arch_memory_deny_write_exec_supported(void)
{ … }
#define arch_memory_deny_write_exec_supported …
#endif

/*
 * 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)
{ … }

#endif /* _LINUX_MMAN_H */