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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id EFBB6C02198 for ; Tue, 18 Feb 2025 11:51:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 82C1A280120; Tue, 18 Feb 2025 06:51:22 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 7DAE728011A; Tue, 18 Feb 2025 06:51:22 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6A23B280120; Tue, 18 Feb 2025 06:51:22 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 4902C28011A for ; Tue, 18 Feb 2025 06:51:22 -0500 (EST) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id E8AB7B1707 for ; Tue, 18 Feb 2025 11:51:21 +0000 (UTC) X-FDA: 83132899962.30.A2AAF8D Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by imf24.hostedemail.com (Postfix) with ESMTP id 4B864180020 for ; Tue, 18 Feb 2025 11:51:17 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=none; spf=pass (imf24.hostedemail.com: domain of tongtiangen@huawei.com designates 45.249.212.189 as permitted sender) smtp.mailfrom=tongtiangen@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1739879479; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=QmDB2s0hgiezmOzzPHSZXy+cZE0dzTWlpWB06SQm1SU=; b=WBQbAygMP35iF9w7GtPP33XngiVC8CYWOOAukLFIns7Rp2EHnl0um/1e1T9adD98Mb15Eq zbbj1MvERQrZ2Rm71AsCidS2K9rYzAHjzuuhOS1n4zi4CuwG2T5P7morLl8WhTf37TKQP8 AIQnBbIiewwYHr/7F16KizLFQqNi9eQ= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=none; spf=pass (imf24.hostedemail.com: domain of tongtiangen@huawei.com designates 45.249.212.189 as permitted sender) smtp.mailfrom=tongtiangen@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1739879479; a=rsa-sha256; cv=none; b=omx3V2mJr5pBhLDE+d83mIZVpuJaM7qWuxgIwUh+RywypCX0W0ugmVKkk/K2p4CS1DrHOh eCJ1PzFW77VeK1d/OCeyHGf3MU3TWg9NFpJ+2mZEP7IzRBLupQUfIATnIJHmrrDeCTbCgk K04KvfZRcZT2ph0EpBH/WqQduWbOGwQ= Received: from mail.maildlp.com (unknown [172.19.163.174]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4YxyT969VDzTjWs; Tue, 18 Feb 2025 19:48:13 +0800 (CST) Received: from kwepemk500005.china.huawei.com (unknown [7.202.194.90]) by mail.maildlp.com (Postfix) with ESMTPS id 6C7E4140361; Tue, 18 Feb 2025 19:51:13 +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; Tue, 18 Feb 2025 19:51:11 +0800 Message-ID: <3b181285-2ff3-b77a-867b-725f38ea86d3@huawei.com> Date: Tue, 18 Feb 2025 19:51:10 +0800 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> <69955002-c3b1-459d-9b42-8d07475c3fd3@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) X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 4B864180020 X-Stat-Signature: ep66abf7rj1p9ga4urqo1z7qseytao58 X-HE-Tag: 1739879477-148434 X-HE-Meta: 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 0Y8lAMw2 Z8aMbzxIfvo2s/gwv6IHNizywPWgRP3rzEC6U5/4oRpI/JWkpUD0CrUGVt4V45203pyzV/jEid2tEE1vPpIRScWIX9fV3z06v7Rg+GHfFMOR79lzLZvuZjte+4ndywEv+Hhvy/cnszK/Bz//EScyxPlyjkpAE6Rv3xuHIfJ1P51YSsxUKnCf6GuOM1etgAfWY8tuiKIRgTRpgA/5qZ9UIijIRvsioVNuxql62gXp63qXoEIToquJWfTLU97Vl6q0Kn7p4bbh97e7woz6yPhEmBfygawAUWqTBGa/T X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 在 2025/2/17 22:55, Catalin Marinas 写道: > On Mon, Feb 17, 2025 at 04:07:49PM +0800, Tong Tiangen wrote: >> 在 2025/2/15 1:24, Catalin Marinas 写道: >>> On Fri, Feb 14, 2025 at 10:49:01AM +0800, Tong Tiangen wrote: >>>> 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? >>> >>> No, they would have the same exception table, only that we'd interpret >>> it differently depending on whether it's a SEA error or not. Or rather >>> ignore the exception table altogether for non-SEA errors. >> >> You mean to use the same exception type (EX_TYPE_KACCESS_ERR_ZERO) and >> then do different processing on SEA errors and non-SEA errors, right? > > Right. Ok, now we have the same understanding. > >> If so, some instructions of copy_page() did not add to the exception >> table will be added to the exception table, and the original logic will >> be affected. >> >> For example, if an instruction is not added to the exception table, the >> instruction will panic when it triggers a non-SEA error. If this >> instruction is added to the exception table because of SEA processing, >> and then a non-SEA error is triggered, should we fix it? > > No, we shouldn't fix it. The exception table entries have a type > associated. For a non-SEA error, we preserve the original behaviour even > if we find a SEA-specific entry in the exception table. You already need > such logic even if you duplicate the code for configurations where you > have MC enabled. So we need another way to distinguish the different processing of the same exception type on SEA and non-SEA path. For example, using strcut exception_table_entry.data, the disadvantage is that it occupies the future expansion space of data. I still think it's better to use methods like copy_from_user.S and copy_to_user.S calling copy_template.S, and the duplicate code in copy_template.S. Thanks, Tong. >