From nobody Thu Apr 9 13:37:43 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1C195C433FE for ; Mon, 7 Nov 2022 11:49:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231935AbiKGLtO (ORCPT ); Mon, 7 Nov 2022 06:49:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56784 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231995AbiKGLtH (ORCPT ); Mon, 7 Nov 2022 06:49:07 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id BA49A1AD96 for ; Mon, 7 Nov 2022 03:49:04 -0800 (PST) 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 934B01FB; Mon, 7 Nov 2022 03:49:10 -0800 (PST) Received: from a077893.arm.com (unknown [10.163.40.48]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 6087B3F73D; Mon, 7 Nov 2022 03:49:01 -0800 (PST) From: Anshuman Khandual To: linux-arm-kernel@lists.infradead.org Cc: Anshuman Khandual , Catalin Marinas , Will Deacon , Mark Brown , Mark Rutland , Ard Biesheuvel , linux-kernel@vger.kernel.org Subject: [PATCH V2] arm64/mm: Simplify and document pte_to_phys() for 52 bit addresses Date: Mon, 7 Nov 2022 17:18:50 +0530 Message-Id: <20221107114850.2902150-1-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" pte_to_phys() assembly definition does multiple bits field transformations to derive physical address, embedded inside a page table entry. Unlike its C counter part i.e __pte_to_phys(), pte_to_phys() is not very apparent. It simplifies these operations via a new macro PTE_ADDR_HIGH_SHIFT indicating how far the pte encoded higher address bits need to be left shifted. While here, this also updates __pte_to_phys() and __phys_to_pte_val(). Cc: Catalin Marinas Cc: Will Deacon Cc: Mark Brown Cc: Mark Rutland Cc: Ard Biesheuvel Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Suggested-by: Ard Biesheuvel Signed-off-by: Anshuman Khandual Reviewed-by: Ard Biesheuvel --- This applies on v6.1-rc4 Changes in V2: - Added PTE_ADDR_HIGH_SHIFT based method per Ard =20 Changes in V1: https://lore.kernel.org/all/20221031082421.1957288-1-anshuman.khandual@arm.= com/ arch/arm64/include/asm/assembler.h | 8 +++----- arch/arm64/include/asm/pgtable-hwdef.h | 1 + arch/arm64/include/asm/pgtable.h | 4 ++-- 3 files changed, 6 insertions(+), 7 deletions(-) diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/as= sembler.h index e5957a53be39..6a39a3601cf7 100644 --- a/arch/arm64/include/asm/assembler.h +++ b/arch/arm64/include/asm/assembler.h @@ -660,12 +660,10 @@ alternative_endif .endm =20 .macro pte_to_phys, phys, pte -#ifdef CONFIG_ARM64_PA_BITS_52 - ubfiz \phys, \pte, #(48 - 16 - 12), #16 - bfxil \phys, \pte, #16, #32 - lsl \phys, \phys, #16 -#else and \phys, \pte, #PTE_ADDR_MASK +#ifdef CONFIG_ARM64_PA_BITS_52 + orr \phys, \phys, \phys, lsl #PTE_ADDR_HIGH_SHIFT + and \phys, \phys, GENMASK_ULL(PHYS_MASK_SHIFT - 1, PAGE_SHIFT) #endif .endm =20 diff --git a/arch/arm64/include/asm/pgtable-hwdef.h b/arch/arm64/include/as= m/pgtable-hwdef.h index 5ab8d163198f..f658aafc47df 100644 --- a/arch/arm64/include/asm/pgtable-hwdef.h +++ b/arch/arm64/include/asm/pgtable-hwdef.h @@ -159,6 +159,7 @@ #ifdef CONFIG_ARM64_PA_BITS_52 #define PTE_ADDR_HIGH (_AT(pteval_t, 0xf) << 12) #define PTE_ADDR_MASK (PTE_ADDR_LOW | PTE_ADDR_HIGH) +#define PTE_ADDR_HIGH_SHIFT 36 #else #define PTE_ADDR_MASK PTE_ADDR_LOW #endif diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgta= ble.h index 71a1af42f0e8..daedd6172227 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -77,11 +77,11 @@ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof= (unsigned long)]; static inline phys_addr_t __pte_to_phys(pte_t pte) { return (pte_val(pte) & PTE_ADDR_LOW) | - ((pte_val(pte) & PTE_ADDR_HIGH) << 36); + ((pte_val(pte) & PTE_ADDR_HIGH) << PTE_ADDR_HIGH_SHIFT); } static inline pteval_t __phys_to_pte_val(phys_addr_t phys) { - return (phys | (phys >> 36)) & PTE_ADDR_MASK; + return (phys | (phys >> PTE_ADDR_HIGH_SHIFT)) & PTE_ADDR_MASK; } #else #define __pte_to_phys(pte) (pte_val(pte) & PTE_ADDR_MASK) --=20 2.25.1