[PATCH 0/5] riscv: Use READ_ONCE()/WRITE_ONCE() for pte accesses

From: Alexandre Ghiti
Date: Mon Oct 02 2023 - 11:10:44 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/

Alexandre Ghiti (5):
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: Suffix all page table entry pointers with 'p'
riscv: Use accessors to page table entries instead of direct
dereference

arch/riscv/include/asm/kfence.h | 6 +-
arch/riscv/include/asm/kvm_host.h | 2 +-
arch/riscv/include/asm/pgalloc.h | 86 ++++++++++----------
arch/riscv/include/asm/pgtable-64.h | 26 +++---
arch/riscv/include/asm/pgtable.h | 33 ++------
arch/riscv/kernel/efi.c | 2 +-
arch/riscv/kvm/mmu.c | 44 +++++-----
arch/riscv/mm/Makefile | 3 +-
arch/riscv/mm/fault.c | 38 ++++-----
arch/riscv/mm/hugetlbpage.c | 80 +++++++++----------
arch/riscv/mm/init.c | 30 +++----
arch/riscv/mm/kasan_init.c | 119 ++++++++++++++--------------
arch/riscv/mm/pageattr.c | 74 +++++++++--------
arch/riscv/mm/pgtable.c | 71 +++++++++++------
include/linux/pgtable.h | 21 +++++
15 files changed, 334 insertions(+), 301 deletions(-)

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2.39.2