[PATCH v2 0/4] riscv: Use READ_ONCE()/WRITE_ONCE() for pte accesses

From: Alexandre Ghiti
Date: Wed Dec 13 2023 - 15:30:23 EST


This series is a follow-up for riscv of a recent series from Ryan [1] which
converts all direct dereferences of pte_t into a ptet_get() access.

The goal here for riscv is to use READ_ONCE()/WRITE_ONCE() for all page
table entries accesses to avoid any compiler transformation when the
hardware can concurrently modify the page tables entries (A/D bits for
example).

I went a bit further and added pud/p4d/pgd_get() helpers as such concurrent
modifications can happen too at those levels.

[1] https://lore.kernel.org/all/20230612151545.3317766-1-ryan.roberts@xxxxxxx/

Changes in v2:
- Fix the kernel test report on arm32
- Remove the pte suffix patch
- Fix pud_offset/p4d_offset which were missing the use of accessors
- Rebase on top of 6.7-rc4

Alexandre Ghiti (4):
riscv: Use WRITE_ONCE() when setting page table entries
mm: Introduce pudp/p4dp/pgdp_get() functions
riscv: mm: Only compile pgtable.c if MMU
riscv: Use accessors to page table entries instead of direct
dereference

arch/arm/include/asm/pgtable.h | 2 ++
arch/riscv/include/asm/kfence.h | 4 +--
arch/riscv/include/asm/pgtable-64.h | 22 +++----------
arch/riscv/include/asm/pgtable.h | 33 +++++--------------
arch/riscv/kernel/efi.c | 2 +-
arch/riscv/kvm/mmu.c | 22 ++++++-------
arch/riscv/mm/Makefile | 3 +-
arch/riscv/mm/fault.c | 16 ++++-----
arch/riscv/mm/hugetlbpage.c | 12 +++----
arch/riscv/mm/kasan_init.c | 45 +++++++++++++------------
arch/riscv/mm/pageattr.c | 44 ++++++++++++-------------
arch/riscv/mm/pgtable.c | 51 ++++++++++++++++++++++++++---
include/linux/pgtable.h | 21 ++++++++++++
13 files changed, 157 insertions(+), 120 deletions(-)

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2.39.2