From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 58FC92FDC3C for ; Wed, 13 May 2026 04:47:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778647630; cv=none; b=j1XCscYGKn0cwL+SU+AxigQMxpQwzGvu7dW1xImhBWO/z/idWQXFO99/c/zD44pTOAdFL8uv6Rwb1VIH1wLOZ/DvqVa9ylyi3KFVvrY0z27LWdR9c60x6knLJvjW6hdtKrVciInv7waxvctxcwg8vMUBGdVq8ob9usU2YBAoS5U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778647630; c=relaxed/simple; bh=qZRT11Pcv3c1+xfoRpChjOYyIamlquzWNvdlouCB9wA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kjUwVbcJev2KZGHMT2CH7mWo90WqRdtpVA9trE95spNCycQrw5yn0gFLniNKCYvQ8huh1XkASFCReqqtpkwhbGBOgZCmBAswwWcJh6OzrmxTp+QA3L9blU9oRtcoUUGtpZbjxgbs8bIOlrWLyhyZ32HZ0wikL7ExzD1f/VkPULw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=QGn34Wxt; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="QGn34Wxt" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6666A1595; Tue, 12 May 2026 21:47:02 -0700 (PDT) Received: from a085714.blr.arm.com (a085714.arm.com [10.164.18.87]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id B4A2D3F7B4; Tue, 12 May 2026 21:47:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1778647627; bh=qZRT11Pcv3c1+xfoRpChjOYyIamlquzWNvdlouCB9wA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QGn34WxtPycq4tT82I1IUAG/h7SpF+s9fFU7N/NJJ7lJQdfkJqw6iN9OQb6AnD9Lw KFs0rYW+3MW2dTxrceVMe00MeR9+1xEAfsG0fsgGJwR2tkzTDRM4ampq4A1MKI6xXl wU/BUJckEE0ESfiW6jr4WvKjWt/mgSRaiVRofib8= From: Anshuman Khandual To: linux-arm-kernel@lists.infradead.org Cc: Anshuman Khandual , Catalin Marinas , Will Deacon , Ryan Roberts , Mark Rutland , Lorenzo Stoakes , Andrew Morton , David Hildenbrand , Mike Rapoport , Linu Cherian , Usama Arif , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [RFC V2 08/14] arm64/mm: Route all pgtable writes via pxxval_set() Date: Wed, 13 May 2026 10:15:41 +0530 Message-ID: <20260513044547.4128549-9-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260513044547.4128549-1-anshuman.khandual@arm.com> References: <20260513044547.4128549-1-anshuman.khandual@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Currently pxxval_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 Cc: Will Deacon Cc: Ryan Roberts Cc: Mark Rutland Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual --- Changes in RFC V2: - Renamed all ptdesc_ instances as pxxval_ instead 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 72da582e8d12..c71bb829e9f1 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 pxxval_get(x) READ_ONCE(x) +#define pxxval_set(x, val) WRITE_ONCE(x, val) #define pmdp_get pmdp_get static inline pmd_t pmdp_get(pmd_t *pmdp) @@ -385,7 +386,7 @@ static inline pte_t pte_clear_uffd_wp(pte_t pte) static inline void __set_pte_nosync(pte_t *ptep, pte_t pte) { - WRITE_ONCE(*ptep, pte); + pxxval_set(*ptep, pte); } static inline void __set_pte_complete(pte_t pte) @@ -856,7 +857,7 @@ static inline void set_pmd(pmd_t *pmdp, pmd_t pmd) } #endif /* __PAGETABLE_PMD_FOLDED */ - WRITE_ONCE(*pmdp, pmd); + pxxval_set(*pmdp, pmd); if (pmd_valid(pmd)) queue_pte_barriers(); @@ -921,7 +922,7 @@ static inline void set_pud(pud_t *pudp, pud_t pud) return; } - WRITE_ONCE(*pudp, pud); + pxxval_set(*pudp, pud); if (pud_valid(pud)) queue_pte_barriers(); @@ -1003,7 +1004,7 @@ static inline void set_p4d(p4d_t *p4dp, p4d_t p4d) return; } - WRITE_ONCE(*p4dp, p4d); + pxxval_set(*p4dp, p4d); queue_pte_barriers(); } @@ -1131,7 +1132,7 @@ static inline void set_pgd(pgd_t *pgdp, pgd_t pgd) return; } - WRITE_ONCE(*pgdp, pgd); + pxxval_set(*pgdp, pgd); queue_pte_barriers(); } diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 7fbb2ef86cfa..6eb92d8f46be 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -76,7 +76,7 @@ void noinstr set_swapper_pgd(pgd_t *pgdp, pgd_t pgd) * writable in the kernel mapping. */ if (rodata_is_rw) { - WRITE_ONCE(*pgdp, pgd); + pxxval_set(*pgdp, pgd); dsb(ishst); isb(); return; @@ -84,7 +84,7 @@ 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); + pxxval_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 -- 2.43.0