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 X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2E08BC432C0 for ; Tue, 19 Nov 2019 01:14:07 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id EFAFE22313 for ; Tue, 19 Nov 2019 01:14:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="nmJLyua/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EFAFE22313 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date: Message-ID:From:References:To:Subject:Reply-To:Content-ID:Content-Description :Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Ax6J1rwZS8oohvqzsFL5O5GH/28RgSrise8ZJBw2QKc=; b=nmJLyua/Hzd+Vm 4wg9D3skYzZWRifF5Em51V+IGxa0oi9DQ4D3VO4jGkT6/tL+ul72RxIevgIt6VTHzMNv6twaZHQ+3 9yrylAEqnwFThN0pze30lRLdzQMAgraYDBtsf0STFM7yOuYVMjglf8FL9I0sTJjgYNfiVSP1aZuCn eQN7KhBYsgBVG2GD4HgGWK8cF9Czznhez1wH9WG7BOxsYS3mcMHXjYK7VmO+g8/WFsXIr+aj+leJr d1prw+EDGAfK7AapXq1LHnm/h74drc3EurIHVFtbALuAWin30j1BuV7MG1i38/Qu2927XIzICbK5l NTRVmKdMA2m8vfwwq97A==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iWs5j-0001Eh-Cq; Tue, 19 Nov 2019 01:14:03 +0000 Received: from szxga05-in.huawei.com ([45.249.212.191] helo=huawei.com) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1iWs5g-0001Dc-0S for linux-arm-kernel@lists.infradead.org; Tue, 19 Nov 2019 01:14:01 +0000 Received: from DGGEMS405-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id F23E3FCA1D89BD2D1402; Tue, 19 Nov 2019 09:13:52 +0800 (CST) Received: from [127.0.0.1] (10.177.223.23) by DGGEMS405-HUB.china.huawei.com (10.3.19.205) with Microsoft SMTP Server id 14.3.439.0; Tue, 19 Nov 2019 09:13:46 +0800 Subject: Re: [RFC PATCH v2] arm64: cpufeatures: add support for tlbi range instructions To: Marc Zyngier , Zhenyu Ye References: <5DC960EB.9050503@huawei.com> <20191111132716.GA9394@willie-the-truck> <5DC96660.8040505@huawei.com> From: Hanjun Guo Message-ID: Date: Tue, 19 Nov 2019 09:13:17 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Originating-IP: [10.177.223.23] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191118_171400_217926_A23F3A1E X-CRM114-Status: GOOD ( 14.78 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, wanghuiqiang , suzuki.poulose@arm.com, catalin.marinas@arm.com, linux-kernel@vger.kernel.org, xiexiangyou@huawei.com, Linuxarm , Shaokun Zhang , arm@kernel.org, tangnianyao@huawei.com, Will Deacon , "linux-arm-kernel@lists.infradead.org" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org +Cc linux-arm-kernel mailing list and Shaokun. Hi Marc, On 2019/11/11 22:04, Marc Zyngier wrote: > On 2019-11-11 14:56, Zhenyu Ye wrote: >> On 2019/11/11 21:27, Will Deacon wrote: >>> On Mon, Nov 11, 2019 at 09:23:55PM +0800, Zhenyu Ye wrote: [...] >>> >>> How does this address my concerns here: >>> >>> >>> https://lore.kernel.org/linux-arm-kernel/20191031131649.GB27196@willie-the-truck/ >>> >>> ? >>> >>> Will >> >> I think your concern is more about the hardware level, and we can do >> nothing about >> this at all. The interconnect/DVM implementation is not exposed to >> software layer >> (and no need), and may should be constrained at hardware level. > > You're missing the point here: the instruction may be implemented > and perfectly working at the CPU level, and yet not carried over > the interconnect. In this situation, other CPUs may not observe > the DVM messages instructing them of such invalidation, and you'll end > up with memory corruption. > > So, in the absence of an architectural guarantee that range invalidation > is supported and observed by all the DVM agents in the system, there must > be a firmware description for it on which the kernel can rely. I'm thinking of how to add a firmware description for it, how about this: Adding a system level flag to indicate the supporting of TIBi by range, which means adding a binding name for example "tlbi-by-range" at system level in the dts file, or a tlbi by range flag in ACPI FADT table, then we use the ID register per-cpu and the system level flag as if (cpus_have_const_cap(ARM64_HAS_TLBI_BY_RANGE) && system_level_tlbi_by_range) flush_tlb_by_range() else flush_tlb_range() And this seems work for heterogeneous system (olny parts of the CPU support TLBi by range) as well, correct me if anything wrong. Thanks Hanjun _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel