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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ASM_MMAN_H__
#define __ASM_MMAN_H__
#include <linux/compiler.h>
#include <linux/types.h>
#include <uapi/asm/mman.h>
static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot,
unsigned long pkey __always_unused)
{
unsigned long ret = 0;
if (system_supports_bti() && (prot & PROT_BTI))
ret |= VM_ARM64_BTI;
if (system_supports_mte() && (prot & PROT_MTE))
ret |= VM_MTE;
return ret;
}
#define arch_calc_vm_prot_bits(prot, pkey) arch_calc_vm_prot_bits(prot, pkey)
static inline unsigned long arch_calc_vm_flag_bits(unsigned long flags)
{
/*
* Only allow MTE on anonymous mappings as these are guaranteed to be
* backed by tags-capable memory. The vm_flags may be overridden by a
* filesystem supporting MTE (RAM-based).
*/
if (system_supports_mte() && (flags & MAP_ANONYMOUS))
return VM_MTE_ALLOWED;
return 0;
}
#define arch_calc_vm_flag_bits(flags) arch_calc_vm_flag_bits(flags)
static inline pgprot_t arch_vm_get_page_prot(unsigned long vm_flags)
{
pteval_t prot = 0;
if (vm_flags & VM_ARM64_BTI)
prot |= PTE_GP;
/*
* There are two conditions required for returning a Normal Tagged
* memory type: (1) the user requested it via PROT_MTE passed to
* mmap() or mprotect() and (2) the corresponding vma supports MTE. We
* register (1) as VM_MTE in the vma->vm_flags and (2) as
* VM_MTE_ALLOWED. Note that the latter can only be set during the
* mmap() call since mprotect() does not accept MAP_* flags.
* Checking for VM_MTE only is sufficient since arch_validate_flags()
* does not permit (VM_MTE & !VM_MTE_ALLOWED).
*/
if (vm_flags & VM_MTE)
prot |= PTE_ATTRINDX(MT_NORMAL_TAGGED);
return __pgprot(prot);
}
#define arch_vm_get_page_prot(vm_flags) arch_vm_get_page_prot(vm_flags)
static inline bool arch_validate_prot(unsigned long prot,
unsigned long addr __always_unused)
{
unsigned long supported = PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM;
if (system_supports_bti())
supported |= PROT_BTI;
if (system_supports_mte())
supported |= PROT_MTE;
return (prot & ~supported) == 0;
}
#define arch_validate_prot(prot, addr) arch_validate_prot(prot, addr)
static inline bool arch_validate_flags(unsigned long vm_flags)
{
if (!system_supports_mte())
return true;
/* only allow VM_MTE if VM_MTE_ALLOWED has been set previously */
return !(vm_flags & VM_MTE) || (vm_flags & VM_MTE_ALLOWED);
}
#define arch_validate_flags(vm_flags) arch_validate_flags(vm_flags)
#endif /* ! __ASM_MMAN_H__ */
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