[RFC V2 11/14] arm64/mm: Override read-write accessors for vm_page_prot

[Anshuman Khandual]

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

Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Will Deacon <will at kernel.org>
Cc: Ryan Roberts <ryan.roberts at arm.com>
Cc: Mark Rutland <mark.rutland at arm.com>
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-kernel at vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual at arm.com>
---
Changes in RFC V2:

- Dropped _once from pgprot_read/write() per Mike
- Renamed all ptdesc_ instances as pxxval_ instead

 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 4065b68e8d79..c9457d133ae9 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 pxxval_get(*pgdp);
 }
 
+#define pgprot_read pgprot_read
+static inline pgprot_t pgprot_read(pgprot_t *prot)
+{
+	return pxxval_get(*prot);
+}
+
+#define pgprot_write pgprot_write
+static inline void pgprot_write(pgprot_t *prot, pgprot_t val)
+{
+	pxxval_set(*prot, val);
+}
+
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 #define __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
 
-- 
2.43.0