[RFC V1 13/16] arm64/mm: Override read-write accessors for vm_page_prot

[Anshuman Khandual]

Override pgprot_[read|write]_once() accessors using ptdesc_[get|set]()
providing required single copy atomic operation for vma->vm_page_prot.

Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
 arch/arm64/include/asm/pgtable.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index c4142b734112..b39d3d3c5dfc 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -122,6 +122,18 @@ static inline pgd_t pgdp_get(pgd_t *pgdp)
 	return ptdesc_get(*pgdp);
 }
 
+#define pgprot_read_once pgprot_read_once
+static inline pgprot_t pgprot_read_once(pgprot_t *prot)
+{
+	return ptdesc_get(*prot);
+}
+
+#define pgprot_write_once pgprot_write_once
+static inline void pgprot_write_once(pgprot_t *prot, pgprot_t val)
+{
+	ptdesc_set(*prot, val);
+}
+
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 #define __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
 
-- 
2.43.0