[PATCH] arm64/mm: Avoid direct referencing page table enties in map_range()

[Anshuman Khandual]

Like else where in arm64 platform, use WRITE_ONCE() in map_range() while
creating page table entries. This avoids referencing page table entries
directly.

Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
 arch/arm64/kernel/pi/map_range.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kernel/pi/map_range.c b/arch/arm64/kernel/pi/map_range.c
index 5410b2cac590..b93b70cdfb62 100644
--- a/arch/arm64/kernel/pi/map_range.c
+++ b/arch/arm64/kernel/pi/map_range.c
@@ -56,8 +56,8 @@ void __init map_range(u64 *pte, u64 start, u64 end, u64 pa, pgprot_t prot,
 			 * table mapping if necessary and recurse.
 			 */
 			if (pte_none(*tbl)) {
-				*tbl = __pte(__phys_to_pte_val(*pte) |
-					     PMD_TYPE_TABLE | PMD_TABLE_UXN);
+				WRITE_ONCE(*tbl, __pte(__phys_to_pte_val(*pte) |
+					   PMD_TYPE_TABLE | PMD_TABLE_UXN));
 				*pte += PTRS_PER_PTE * sizeof(pte_t);
 			}
 			map_range(pte, start, next, pa, prot, level + 1,
@@ -79,7 +79,7 @@ void __init map_range(u64 *pte, u64 start, u64 end, u64 pa, pgprot_t prot,
 				protval &= ~PTE_CONT;
 
 			/* Put down a block or page mapping */
-			*tbl = __pte(__phys_to_pte_val(pa) | protval);
+			WRITE_ONCE(*tbl, __pte(__phys_to_pte_val(pa) | protval));
 		}
 		pa += next - start;
 		start = next;
-- 
2.30.2