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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 DD75CC021A0 for ; Fri, 14 Feb 2025 01:47:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:CC:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=/xou2uZRbnImxMqVFANwRB9AlkIaAnGUiupsZKCr/kI=; b=t1QKbPBAUohFZMVRz+r5a3Sf/X T5NUXQ5yeaMqyuMHN8uqxsoPDT83ZRmkHYYw07FlIOJsVSAjVy4bH23+tR/A3GBvr8GeLj5bC/ele ZEdofbciz4RPVqPVJkzGke/JZO1z7arcJLBU89KELBjpyZMwlSszFRplddKWBh5Gu5pwjkLe3s6m4 ubtMARAIs07J/s9sy1W19TkMBZbp5/0Y/C7J6HJM0jbPyfJ0BRHmAMp19bBqbuCFZJsk04u4GCgC2 fPILPOkn+gOSuBbcc0HH9V8d/y5Csnvkp/mx1V3wri5Zq5oVCPpvFDEjrEs0OWvIaHYhIszQbVkiW prZAKAIw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tiknn-0000000DDqs-3Xkt; Fri, 14 Feb 2025 01:47:35 +0000 Received: from szxga08-in.huawei.com ([45.249.212.255]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tikmI-0000000DDeu-1vP1 for linux-arm-kernel@lists.infradead.org; Fri, 14 Feb 2025 01:46:07 +0000 Received: from mail.maildlp.com (unknown [172.19.162.254]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4YvFBx5FCVz1W5g8; Fri, 14 Feb 2025 09:41:29 +0800 (CST) Received: from kwepemk500005.china.huawei.com (unknown [7.202.194.90]) by mail.maildlp.com (Postfix) with ESMTPS id CA0DB18032E; Fri, 14 Feb 2025 09:45:58 +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 09:45:56 +0800 Message-ID: <6aecab97-5ba8-38dd-1df7-87e5f557017e@huawei.com> Date: Fri, 14 Feb 2025 09:45:55 +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> 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: dggems703-chm.china.huawei.com (10.3.19.180) To kwepemk500005.china.huawei.com (7.202.194.90) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250213_174602_804360_0EDEAE1E X-CRM114-Status: GOOD ( 22.11 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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. The location of the added exception table entry is likely to appear on the a path, which should not be avoided. What we can do is merge duplicate code as much as possible, and extract common code into common files, as we did in this patch. > >> 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. Does MOPS also support features similar to memory error safe? I'll see how he handles it. >