[PATCH V2 03/14] arm64/mm: Route all pgtable writes via ptval_set()
From: Anshuman Khandual <hidden>
Date: 2026-09-07 03:51:06
Also in:
linux-mm, lkml
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
Currently ptval_set() is defined as WRITE_ONCE() but this will change for D128 pgtable builds, for which WRITE_ONCE() is not sufficient for single copy atomicity. In future this infrastructure can be used for D128 to maintain single copy atomicity semantics with inline asm blocks. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual <redacted> --- arch/arm64/include/asm/pgtable.h | 11 ++++++----- arch/arm64/mm/mmu.c | 4 ++-- 2 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index f764132ca34e..692669ea2d29 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h@@ -85,6 +85,7 @@ static inline void arch_leave_lazy_mmu_mode(void) } #define ptval_get(x) READ_ONCE(x) +#define ptval_set(x, val) WRITE_ONCE(x, val) #define pmdp_get pmdp_get static inline pmd_t pmdp_get(pmd_t *pmdp)
@@ -386,7 +387,7 @@ static inline pte_t pte_clear_uffd(pte_t pte) static inline void __set_pte_nosync(pte_t *ptep, pte_t pte) { - WRITE_ONCE(*ptep, pte); + ptval_set(*ptep, pte); } static inline void __set_pte_complete(pte_t pte)
@@ -809,7 +810,7 @@ static inline void set_pmd(pmd_t *pmdp, pmd_t pmd) } #endif /* __PAGETABLE_PMD_FOLDED */ - WRITE_ONCE(*pmdp, pmd); + ptval_set(*pmdp, pmd); if (pmd_valid(pmd)) queue_pte_barriers();
@@ -871,7 +872,7 @@ static inline void set_pud(pud_t *pudp, pud_t pud) return; } - WRITE_ONCE(*pudp, pud); + ptval_set(*pudp, pud); if (pud_valid(pud)) queue_pte_barriers();
@@ -950,7 +951,7 @@ static inline void set_p4d(p4d_t *p4dp, p4d_t p4d) return; } - WRITE_ONCE(*p4dp, p4d); + ptval_set(*p4dp, p4d); queue_pte_barriers(); }
@@ -1075,7 +1076,7 @@ static inline void set_pgd(pgd_t *pgdp, pgd_t pgd) return; } - WRITE_ONCE(*pgdp, pgd); + ptval_set(*pgdp, pgd); queue_pte_barriers(); }
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 46ff9a92e73a..44af53dc9ba8 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c@@ -75,7 +75,7 @@ void noinstr set_swapper_pgd(pgd_t *pgdp, pgd_t pgd) * writable in the kernel mapping. */ if (rodata_is_rw) { - WRITE_ONCE(*pgdp, pgd); + ptval_set(*pgdp, pgd); dsb(ishst); isb(); return;
@@ -83,7 +83,7 @@ void noinstr set_swapper_pgd(pgd_t *pgdp, pgd_t pgd) spin_lock(&swapper_pgdir_lock); fixmap_pgdp = pgd_set_fixmap(__pa_symbol(pgdp)); - WRITE_ONCE(*fixmap_pgdp, pgd); + ptval_set(*fixmap_pgdp, pgd); /* * We need dsb(ishst) here to ensure the page-table-walker sees * our new entry before set_p?d() returns. The fixmap's
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2.43.0