summaryrefslogtreecommitdiff
path: root/arch/arm64/mm/mmap.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm64/mm/mmap.c')
-rw-r--r--arch/arm64/mm/mmap.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c
index 77ada00280d9..78e9490f748d 100644
--- a/arch/arm64/mm/mmap.c
+++ b/arch/arm64/mm/mmap.c
@@ -55,3 +55,28 @@ static int __init adjust_protection_map(void)
return 0;
}
arch_initcall(adjust_protection_map);
+
+pgprot_t vm_get_page_prot(unsigned long vm_flags)
+{
+ pteval_t prot = pgprot_val(protection_map[vm_flags &
+ (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]);
+
+ 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);
+}
+EXPORT_SYMBOL(vm_get_page_prot);