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From: Muhammad Usama Anjum <usama.anjum@arm.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
	 Will Deacon <will@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	 Ryan Roberts <ryan.roberts@arm.com>,
	Ard Biesheuvel <ardb@kernel.org>,
	 Ilias Apalodimas <ilias.apalodimas@linaro.org>,
	 Andrey Ryabinin <ryabinin.a.a@gmail.com>,
	 Alexander Potapenko <glider@google.com>,
	 Andrey Konovalov <andreyknvl@gmail.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	 Vincenzo Frascino <vincenzo.frascino@arm.com>,
	 Andrew Morton <akpm@linux-foundation.org>,
	 David Hildenbrand <david@kernel.org>,
	Lorenzo Stoakes <ljs@kernel.org>,
	 "Liam R. Howlett" <liam@infradead.org>,
	Vlastimil Babka <vbabka@kernel.org>,
	 Mike Rapoport <rppt@kernel.org>,
	Suren Baghdasaryan <surenb@google.com>,
	 Michal Hocko <mhocko@suse.com>
Cc: linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,  linux-efi@vger.kernel.org,
	kasan-dev@googlegroups.com, linux-mm@kvack.org,
	 Muhammad Usama Anjum <usama.anjum@arm.com>
Subject: [PATCH v2 3/6] arm64: use hw_pte_val for HW PTE loads and stores
Date: Tue, 22 Sep 2026 18:31:58 +0100	[thread overview]
Message-ID: <20260922-pte0_arm-v2-3-a3f1ddff0a8a@arm.com> (raw)
In-Reply-To: <20260922-pte0_arm-v2-0-a3f1ddff0a8a@arm.com>

__ptep_get() returns a SW PTE value, while __set_pte_nosync() accepts
one. When HW PTE storage uses a distinct hw_pte_t, reading or writing
*ptep as a pte_t no longer satisfies those interfaces.

Use hw_pte_val() to expose the pteval_t stored in either the hw_pte_t
wrapper or its pte_t alias. __set_pte_nosync() writes pte_val(pte) to
that storage, while __ptep_get() reads it and reconstructs a pte_t with
__pte().

This avoids imposing a generic conversion interface between HW and SW
PTE representations, which may require architecture-specific context
in the future.

Signed-off-by: Muhammad Usama Anjum <usama.anjum@arm.com>
---
 arch/arm64/include/asm/pgtable.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 4768ec59de555..ce6580ab63128 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -360,7 +360,7 @@ static inline pte_t pte_clear_uffd(pte_t pte)
 
 static inline void __set_pte_nosync(hw_pte_t *ptep, pte_t pte)
 {
-	WRITE_ONCE(*ptep, pte);
+	WRITE_ONCE(hw_pte_val(*ptep), pte_val(pte));
 }
 
 static inline void __set_pte_complete(pte_t pte)
@@ -381,7 +381,7 @@ static inline void __set_pte(hw_pte_t *ptep, pte_t pte)
 
 static inline pte_t __ptep_get(hw_pte_t *ptep)
 {
-	return READ_ONCE(*ptep);
+	return __pte(READ_ONCE(hw_pte_val(*ptep)));
 }
 
 extern void __sync_icache_dcache(pte_t pteval);

-- 
2.47.3


  parent reply	other threads:[~2026-09-22 17:33 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-22 17:31 [PATCH v2 0/6] arm64: distinguish HW PTE pointers from SW PTE value pointers Muhammad Usama Anjum
2026-09-22 17:31 ` [PATCH v2 1/6] arm64: use hw_pte_t for HW PTE pointers Muhammad Usama Anjum
2026-09-22 17:31 ` [PATCH v2 2/6] arm64: use hw_pte_val for HW PTE atomics Muhammad Usama Anjum
2026-09-22 17:31 ` Muhammad Usama Anjum [this message]
2026-09-22 17:31 ` [PATCH v2 4/6] arm64: use hw_pte_t for fixmap HW PTEs Muhammad Usama Anjum
2026-09-22 17:32 ` [PATCH v2 5/6] arm64: use HW PTE accessors in early map_range() Muhammad Usama Anjum
2026-09-22 17:32 ` [PATCH v2 6/6] arm64: enable a distinct type for HW PTEs Muhammad Usama Anjum

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