Re: [PATCH V3 0/4] arm64/mm: Convert pgtable READ_ONCE() as pxdp_get()

[Anshuman Khandual]

On Thu, Sep 24, 2026 at 11:52:10AM +0530, Anshuman Khandual wrote:
> 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 a well.
> 
> 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@xxxxxxx/
> 
> This series applies on v7.3-rc4 but after applying the following patches on
> pgtable entry print standardization posted earlier.
> 
> https://lore.kernel.org/linux-mm/20260831054331.625505-1-anshuman.khandual@xxxxxxx/
> 
> https://lore.kernel.org/linux-mm/20260916044933.2689426-1-anshuman.khandual@xxxxxxx/

Hello Catalin/Andrew,

The above mentioned dependencies are already in mm-unstable, thus reflecting
in linux-next as well. Just to rule out merge conflict - this series applies
cleanly, builds and boots on latest tag next-20261002, which contains above
dependencies. But please do let me know if there are still some issues in
resolving this situation - will be happy to help. Thank you.

- Anshuman

> 
> These patches have been hosted here as well.
> 
> git@xxxxxxxxxxxxxxxxxx:linux-arm/linux-anshuman.git (arm64_pxdp_get_v3)
> 
> Changes in V3:
> 
> - Added overrides for pxdp_get() and replaced remaining READ_ONCE()
> - Updated all commit messages as required
> - Dropped previous tags
> 
> Changes in V2:
> 
> https://lore.kernel.org/all/20260922061638.3967467-1-anshuman.khandual@xxxxxxx/
> 
> - Rebased on v7.3-rc4 along with all latest dependencies
> - Updated commit messages per Ryan
> - Added tags from Ryan
> 
> Changes in V1:
> 
> https://lore.kernel.org/all/20260903060657.2717457-1-anshuman.khandual@xxxxxxx/
> 
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Will Deacon <will@xxxxxxxxxx>
> Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Cc: Lorenzo Stoakes <ljs@xxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: David Hildenbrand <david@xxxxxxxxxx>
> Cc: Mike Rapoport <rppt@xxxxxxxxxx>
> Cc: Linu Cherian <linu.cherian@xxxxxxx>
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Cc: linux-mm@xxxxxxxxx
> 
> Anshuman Khandual (4):
>   arm64/mm: Use pmdp_get() for PMD accesses
>   arm64/mm: Use pudp_get() for PUD accesses
>   arm64/mm: Use p4dp_get() for P4D accesses
>   arm64/mm: Use pgdp_get() for PGD accesses
> 
>  arch/arm64/include/asm/pgtable.h | 40 +++++++++++++++++----
>  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, 95 insertions(+), 69 deletions(-)
> 
> -- 
> 2.43.0
>