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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CCC96C433EF for ; Tue, 2 Nov 2021 06:45:15 +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 8E88060F02 for ; Tue, 2 Nov 2021 06:45:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 8E88060F02 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=JlAsYul+em0wmPh6KQgDGmaWOpiwcc+u1M1onCUnqt8=; b=1ZBm/hQ/66aB4X wNqxi6pQb7ynzc1b0bSXeELEPgBn2/NezvTjGrEhL84KFbW8OU+NLFb42byDh1f1hrpy+jZ/01EGF Gmzk0M/wlEbmzfqV3wpcsL8Wb8HahOWtTLGCt+VaUXEuBiXB3YjIWoaISs/0ECL0MkfpY8bJ4Z56b 7fxolh1XNft7D9BgNFmYGZ/WTrDhx8xj5tFnGfjeoc/1iIbrj+DE4PKxysl0Z2Zuz9031PMgcf3y5 eO0QuLZSMcKWQlp0f9Wta2LtOBwAXXWGlcR0EiUs+oscUy2joRIWk14FSHj34o565WWSPAxgJviJV 2grKLONUdNwHnWrK+QZg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mhnWc-000fy1-Fr; Tue, 02 Nov 2021 06:44:02 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mhnWZ-000fxL-Al; Tue, 02 Nov 2021 06:44:00 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 85F8768AFE; Tue, 2 Nov 2021 07:43:56 +0100 (CET) Date: Tue, 2 Nov 2021 07:43:56 +0100 From: Christoph Hellwig To: Walter Wu Cc: Ard Biesheuvel , Christoph Hellwig , Marek Szyprowski , Robin Murphy , Matthias Brugger , Linux IOMMU , Linux Kernel Mailing List , Linux ARM , wsd_upstream , linux-mediatek@lists.infradead.org, Andrew Morton , Will Deacon Subject: Re: [PATCH] dma-direct: fix DMA_ATTR_NO_KERNEL_MAPPING Message-ID: <20211102064356.GB27749@lst.de> References: <20211101031558.7184-1-walter-zh.wu@mediatek.com> <76840b40fcf26a65467931a73f236982ad39989c.camel@mediatek.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211101_234359_543644_D58E8BD4 X-CRM114-Status: GOOD ( 14.63 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Nov 02, 2021 at 11:21:16AM +0800, Walter Wu wrote: > Our platform is arch64. We need a dynamic allocated buffer from CMA is > not to read by CPU peculative execution, so we need to remove its > kernel mapping. If your CPU speculates into unused kernel direct mappings your have a worse problem than this, because all the dma coherent allocations for non-coherent devices still have a cachable direct mapping. Will mentioned he wanted to look into getting rid of that mapping now that the core dma code has the infrastucture for that, so adding him here. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel