[PATCH 0/4] arm64/mm: Convert pgtable READ_ONCE() as pxdp_get()

[Anshuman Khandual]

Route READ_ONCE() accesses on pgtable entries via level specific generic MM
pxdp_get() helpers which platforms could then override when required. These
accessors on arm64, will help in ensuring page table accesses are performed
in an atomic manner while reading 128 bit page table entries later. But for
now they just default to READ_ONCE(), thus preserving existing behaviour on
current D64 translation.

This is similar to generic MM, where all atomic accesses have already been
converted from READ_ONCE() into pgtable level specific accessors.

These are preparatory patches for D128 enablement, although standing their
own for D64 translation as well. These patches are split from earlier D128
V1 series. There are no functional changes here, and besides mm kselftests
do not show any regression.

https://lore.kernel.org/linux-mm/20260729122452.3797443-1-anshuman.khandual@arm.com/

This series applies on v3.7-rc1 but after applying the following patches
related to pgtable entry print standardization posted earlier.

https://lore.kernel.org/linux-mm/20260831054331.625505-1-anshuman.khandual@arm.com/

https://lore.kernel.org/linux-mm/20260901065454.1906343-1-anshuman.khandual@arm.com/

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: Lorenzo Stoakes <ljs at kernel.org>
Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: David Hildenbrand <david at kernel.org>
Cc: Mike Rapoport <rppt at kernel.org>
Cc: Linu Cherian <linu.cherian at arm.com>
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-kernel at vger.kernel.org
Cc: linux-mm at kvack.org

Anshuman Khandual (4):
  arm64/mm: Convert READ_ONCE() as pmdp_get() while accessing PMD
  arm64/mm: Convert READ_ONCE() as pudp_get() while accessing PUD
  arm64/mm: Convert READ_ONCE() as p4dp_get() while accessing P4D
  arm64/mm: Convert READ_ONCE() as pgdp_get() while accessing PGD

 arch/arm64/include/asm/pgtable.h |  6 ++--
 arch/arm64/mm/fault.c            |  8 ++---
 arch/arm64/mm/fixmap.c           |  6 ++--
 arch/arm64/mm/hugetlbpage.c      | 10 +++---
 arch/arm64/mm/kasan_init.c       | 18 +++++-----
 arch/arm64/mm/mmu.c              | 60 ++++++++++++++++----------------
 arch/arm64/mm/pageattr.c         |  8 ++---
 arch/arm64/mm/trans_pgd.c        | 14 ++++----
 8 files changed, 66 insertions(+), 64 deletions(-)

-- 
2.43.0