From mboxrd@z Thu Jan 1 00:00:00 1970 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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E03B5C021A0 for ; Fri, 14 Feb 2025 02:49:14 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4YvGj52MK1z30Sw; Fri, 14 Feb 2025 13:49:13 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip=45.249.212.190 ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1739501353; cv=none; b=LmurcpyQLLbnzA4964PKsoTsHNu7SMjBkDsDgZ9m8BIjnDvcolMuFqocfvmQdFJh56IlY749KUwyO1PinKnB87iLB+1tEUkdBDn+NjUZ4SirrHYhpyAE2avRSCJsalI4omcBV6kwVbraxSMkG1keohKiitIH9eniXQihw32baLLesNZzilakGfVKykfySZ3ermXUbaSHXhjMs1j95Ts3k3oMh7ynx+xu9AwTKLsq/TlVf4S8dd8WZCEHSp9Q1Dt35/vukxODhcgqunfrLdup971svLc84S9X8RU9+F5rPhdNGvi8HZ+GZ62oxCcHnvYRQQ+D8YcK12VpgG4ebAnhXg== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1739501353; c=relaxed/relaxed; bh=Qdv27WOOjvDepPMV24X/lprplWgreW0f92yGmOb5lxY=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=eFxKrTzTOGgXZVIdfBn1b4xrioAML/XhnPMN3U3OocDo5bgf1/p5HLTsLSRnEBFf8OSBu16Uxo3ZfPq+l+cyfLT4ui8QCyK8C3L5reVMK1RauxaT2aOoS3qLeF5ohkPRO6MApDd8frfjeqUjB4OKIqy0AIIDWeeBvHH9/xEqG/Gj3VTsFIcvEnuEhtLn+sheMyxUM/zUKD7OjXPG3KpsOqOMjvsXo6gqmi1Cgb2Xf1o32pjvN5jo/smtqkG631frZgCGKTUS6z1TrXc6a3wI/RTFfRjKRiAFz/tmVKiV9fCLyffI96ope9B+dRYpxJXFYdk3cxK5FFXn7/aqUAU/Sg== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass (client-ip=45.249.212.190; helo=szxga04-in.huawei.com; envelope-from=tongtiangen@huawei.com; receiver=lists.ozlabs.org) smtp.mailfrom=huawei.com Authentication-Results: lists.ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=huawei.com (client-ip=45.249.212.190; helo=szxga04-in.huawei.com; envelope-from=tongtiangen@huawei.com; receiver=lists.ozlabs.org) Received: from szxga04-in.huawei.com (szxga04-in.huawei.com [45.249.212.190]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4YvGj36Dzmz2yVX for ; Fri, 14 Feb 2025 13:49:09 +1100 (AEDT) Received: from mail.maildlp.com (unknown [172.19.163.17]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4YvGcX1dFHz2FdPV; Fri, 14 Feb 2025 10:45:16 +0800 (CST) Received: from kwepemk500005.china.huawei.com (unknown [7.202.194.90]) by mail.maildlp.com (Postfix) with ESMTPS id 362F01A0188; Fri, 14 Feb 2025 10:49:04 +0800 (CST) Received: from [10.174.179.234] (10.174.179.234) by kwepemk500005.china.huawei.com (7.202.194.90) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Fri, 14 Feb 2025 10:49:01 +0800 Message-ID: <69955002-c3b1-459d-9b42-8d07475c3fd3@huawei.com> Date: Fri, 14 Feb 2025 10:49:01 +0800 X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [PATCH v13 4/5] arm64: support copy_mc_[user]_highpage() To: Catalin Marinas CC: Mark Rutland , Jonathan Cameron , Mauro Carvalho Chehab , Will Deacon , Andrew Morton , James Morse , Robin Murphy , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , Michael Ellerman , Nicholas Piggin , Andrey Ryabinin , Alexander Potapenko , Christophe Leroy , Aneesh Kumar K.V , "Naveen N. Rao" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , , "H. Peter Anvin" , Madhavan Srinivasan , , , , , , , Guohanjun References: <20241209024257.3618492-1-tongtiangen@huawei.com> <20241209024257.3618492-5-tongtiangen@huawei.com> From: Tong Tiangen In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.179.234] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To kwepemk500005.china.huawei.com (7.202.194.90) 在 2025/2/13 1:11, Catalin Marinas 写道: > On Mon, Dec 09, 2024 at 10:42:56AM +0800, Tong Tiangen wrote: >> Currently, many scenarios that can tolerate memory errors when copying page >> have been supported in the kernel[1~5], all of which are implemented by >> copy_mc_[user]_highpage(). arm64 should also support this mechanism. >> >> Due to mte, arm64 needs to have its own copy_mc_[user]_highpage() >> architecture implementation, macros __HAVE_ARCH_COPY_MC_HIGHPAGE and >> __HAVE_ARCH_COPY_MC_USER_HIGHPAGE have been added to control it. >> >> Add new helper copy_mc_page() which provide a page copy implementation with >> hardware memory error safe. The code logic of copy_mc_page() is the same as >> copy_page(), the main difference is that the ldp insn of copy_mc_page() >> contains the fixup type EX_TYPE_KACCESS_ERR_ZERO_MEM_ERR, therefore, the >> main logic is extracted to copy_page_template.S. In addition, the fixup of >> MOPS insn is not considered at present. > > Could we not add the exception table entry permanently but ignore the > exception table entry if it's not on the do_sea() path? That would save > some code duplication. I'm sorry, I didn't catch your point, that the do_sea() and non do_sea() paths use different exception tables? My understanding is that the exception table entry problem is fine. After all, the search is performed only after a fault trigger. Code duplication can be solved by extracting repeated logic to a public file. > >> diff --git a/arch/arm64/lib/copy_mc_page.S b/arch/arm64/lib/copy_mc_page.S >> new file mode 100644 >> index 000000000000..51564828c30c >> --- /dev/null >> +++ b/arch/arm64/lib/copy_mc_page.S >> @@ -0,0 +1,37 @@ >> +/* SPDX-License-Identifier: GPL-2.0-only */ >> + >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> + >> +/* >> + * Copy a page from src to dest (both are page aligned) with memory error safe >> + * >> + * Parameters: >> + * x0 - dest >> + * x1 - src >> + * Returns: >> + * x0 - Return 0 if copy success, or -EFAULT if anything goes wrong >> + * while copying. >> + */ >> + .macro ldp1 reg1, reg2, ptr, val >> + KERNEL_MEM_ERR(9998f, ldp \reg1, \reg2, [\ptr, \val]) >> + .endm >> + >> +SYM_FUNC_START(__pi_copy_mc_page) >> +#include "copy_page_template.S" >> + >> + mov x0, #0 >> + ret >> + >> +9998: mov x0, #-EFAULT >> + ret >> + >> +SYM_FUNC_END(__pi_copy_mc_page) >> +SYM_FUNC_ALIAS(copy_mc_page, __pi_copy_mc_page) >> +EXPORT_SYMBOL(copy_mc_page) > [...] >> diff --git a/arch/arm64/lib/copy_page_template.S b/arch/arm64/lib/copy_page_template.S >> new file mode 100644 >> index 000000000000..f96c7988c93d >> --- /dev/null >> +++ b/arch/arm64/lib/copy_page_template.S >> @@ -0,0 +1,70 @@ >> +/* SPDX-License-Identifier: GPL-2.0-only */ >> +/* >> + * Copyright (C) 2012 ARM Ltd. >> + */ >> + >> +/* >> + * Copy a page from src to dest (both are page aligned) >> + * >> + * Parameters: >> + * x0 - dest >> + * x1 - src >> + */ >> + >> +#ifdef CONFIG_AS_HAS_MOPS >> + .arch_extension mops >> +alternative_if_not ARM64_HAS_MOPS >> + b .Lno_mops >> +alternative_else_nop_endif >> + >> + mov x2, #PAGE_SIZE >> + cpypwn [x0]!, [x1]!, x2! >> + cpymwn [x0]!, [x1]!, x2! >> + cpyewn [x0]!, [x1]!, x2! >> + ret >> +.Lno_mops: >> +#endif > [...] > > So if we have FEAT_MOPS, the machine check won't work? > > Kristina is going to post MOPS support for the uaccess routines soon. > You can see how they are wired up and do something similar here. > > But I'd prefer if we had the same code, only the exception table entry > treated differently. Similarly for the MTE tag copying. >