[PATCH v2 0/6] arm64: distinguish HW PTE pointers from SW PTE value pointers

[Muhammad Usama Anjum]

Hi,

The generic series introduces hw_pte_t for HW PTEs, while SW PTE values
use pte_t. This series enables the distinct type on arm64 so the
compiler can distinguish HW PTE pointers (hw_pte_t *) from SW PTE value
pointers (pte_t *).

The conversion updates HW PTE pointers and accessors, including atomic
updates, fixmap, and early page-table construction, before selecting
ARCH_HAS_HW_PTE_T. Higher-level entry types remain out of scope, and
shared helpers retain explicit casts.

The linked generic series is a prerequisite. Its cover contains the
Coccinelle script used for most pointer conversions; the remaining sites
were converted by hand.

Testing:
Testing was performed with and without the series on both x86_64 and
arm64. KUnit and the MM kselftests produced matching before-and-after
results problems or regressions. Fastpath performance testing was also
completed on arm64. No regression was found.

Link: https://lore.kernel.org/all/20260922-pte0-v3-0-5670b8cb9059@arm.com  
Signed-off-by: Muhammad Usama Anjum <usama.anjum at arm.com>
---
Changes in v2:
- Move hw_pte_val() to the generic series and drop an unrelated comment
  change from the atomic-access patch.
- Use raw PTE values instead of generic HW/SW conversion helpers.
- Drop a comment and add testing resutls in the cover letter
- Add Reviewed-by tags.
- Link to v1: https://patch.msgid.link/20260914-pte0_arm-v1-0-bb53b663e396@arm.com

To: Catalin Marinas <catalin.marinas at arm.com>
To: Will Deacon <will at kernel.org>
To: Mark Rutland <mark.rutland at arm.com>
To: Ard Biesheuvel <ardb at kernel.org>
To: Ilias Apalodimas <ilias.apalodimas at linaro.org>
To: Andrey Ryabinin <ryabinin.a.a at gmail.com>
To: Alexander Potapenko <glider at google.com>
To: Andrey Konovalov <andreyknvl at gmail.com>
To: Dmitry Vyukov <dvyukov at google.com>
To: Vincenzo Frascino <vincenzo.frascino at arm.com>
Cc: usama.anjum at arm.com
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-kernel at vger.kernel.org
Cc: linux-efi at vger.kernel.org
Cc: kasan-dev at googlegroups.com

---
Muhammad Usama Anjum (6):
      arm64: use hw_pte_t for HW PTE pointers
      arm64: use hw_pte_val for HW PTE atomics
      arm64: use hw_pte_val for HW PTE loads and stores
      arm64: use hw_pte_t for fixmap HW PTEs
      arm64: use HW PTE accessors in early map_range()
      arm64: enable a distinct type for HW PTEs

 arch/arm64/Kconfig                |   1 +
 arch/arm64/include/asm/hugetlb.h  |  19 ++++----
 arch/arm64/include/asm/pgalloc.h  |   2 +-
 arch/arm64/include/asm/pgtable.h  | 157 ++++++++++++++++++++++++++++++++++------------------------------
 arch/arm64/include/asm/vmalloc.h  |   2 +-
 arch/arm64/kernel/efi.c           |   3 +-
 arch/arm64/kernel/pi/map_kernel.c |   4 +-
 arch/arm64/kernel/pi/map_range.c  |  20 +++++----
 arch/arm64/kernel/pi/pi.h         |   3 +-
 arch/arm64/mm/contpte.c           |  49 ++++++++++----------
 arch/arm64/mm/fault.c             |   7 +--
 arch/arm64/mm/fixmap.c            |   8 ++--
 arch/arm64/mm/hugetlbpage.c       |  48 ++++++++++----------
 arch/arm64/mm/kasan_init.c        |   4 +-
 arch/arm64/mm/mmu.c               |  46 +++++++++++--------
 arch/arm64/mm/pageattr.c          |   4 +-
 arch/arm64/mm/trans_pgd.c         |   4 +-
 17 files changed, 207 insertions(+), 174 deletions(-)
---
base-commit: ead700ca770c82167af32622cf8b68c9f87c3c7c
change-id: 20260911-pte0_arm-f1b7df7c0b51
prerequisite-message-id: 20260922-pte0-v3-0-5670b8cb9059 at arm.com
prerequisite-patch-id: 0114fcc6ab0dbb739b5bb6fc0fe6b1c8f1fa37a1
prerequisite-patch-id: 09fcf65970074620dd3a9cce6850b901beb01db8
prerequisite-patch-id: 9b2fdab97c99effabb85526fa7f141c933b3aa23
prerequisite-patch-id: 1aa309a26d98a1e93a54742705a03567ee93be71
prerequisite-patch-id: ebe32f52c95ad0542982f0b37798d209595e25e1
prerequisite-patch-id: 22950028c3d2060de8acd3fe4a73d755b18215e3
prerequisite-patch-id: a60d249f52d092524176851b2570d7245bb24434
prerequisite-patch-id: 81ebd1378e25d40a1771b53973abcc4defa87535
prerequisite-patch-id: d982f2b00c5eddb2459f69008a73e4f4ae4d8299

Best regards,
--  
Usama