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=-4.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT autolearn=ham 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 DD5CAC04EB9 for ; Wed, 5 Dec 2018 14:46:03 +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 A4EE020878 for ; Wed, 5 Dec 2018 14:46:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="FzSfghkv" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A4EE020878 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.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:References: Message-ID:Subject: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=GD316q41hrdc/jAkqHqN92/6rlFT0rTihEs5ug8E/GY=; b=FzSfghkvFnyqW6 Lajmcm/32YrNhxBpIzHL0iXxvCDZ4+xhBcwtfEYAxd6LncrfhDSD3oaqreoyKcyairT3+y5t0Wr98 5+4xEqGBpsFtlUG07nq5fmgaW1X7M0bvzNLfOPkYw4xsNWYTvQIQM3YQ8O7Q7lgkVk001VnmEI0nR 8CEnj3ibN9vH6RcbWpoNdKeqCPhzTCWozRsZ5OqDZXoMAqUGBOmMbibciWyeZvUDQkjv9npWl6xfw tXjQxyt/VsKO4Ke4cbFUsmrQcpc+zOFe1xnHKL70U2jR1MgTQhpDHil6Vv+LPGZ+wJa50/Qu66zbM /RsUn/X5U25q5TZru0zA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gUYR4-00013G-Ok; Wed, 05 Dec 2018 14:45:58 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gUYR2-000115-2Q for linux-arm-kernel@lists.infradead.org; Wed, 05 Dec 2018 14:45:57 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A06B180D; Wed, 5 Dec 2018 06:45:45 -0800 (PST) Received: from edgewater-inn.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 6F1C13F59C; Wed, 5 Dec 2018 06:45:45 -0800 (PST) Received: by edgewater-inn.cambridge.arm.com (Postfix, from userid 1000) id 2F5D71AE0BC3; Wed, 5 Dec 2018 14:46:06 +0000 (GMT) Date: Wed, 5 Dec 2018 14:46:06 +0000 From: Will Deacon To: Christoph Hellwig Subject: Re: [PATCH v4 3/3] iommu/io-pgtable-arm-v7s: Request DMA32 memory, and improve debugging Message-ID: <20181205144605.GA16171@arm.com> References: <20181205054828.183476-1-drinkcat@chromium.org> <20181205054828.183476-4-drinkcat@chromium.org> <20181205135406.GA29031@infradead.org> <1d211576-9153-cca1-5cd0-8c9881bd3fa4@arm.com> <20181205144308.GA28409@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20181205144308.GA28409@infradead.org> User-Agent: Mutt/1.5.23 (2014-03-12) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20181205_064556_114171_D0999456 X-CRM114-Status: GOOD ( 14.47 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Michal Hocko , Levin Alexander , linux-mm@kvack.org, Christoph Lameter , Nicolas Boichat , Huaisheng Ye , Joerg Roedel , Matthew Wilcox , linux-arm-kernel@lists.infradead.org, David Rientjes , yingjoe.chen@mediatek.com, Vlastimil Babka , Tomasz Figa , Mike Rapoport , Matthias Brugger , Joonsoo Kim , Yong Wu , Robin Murphy , linux-kernel@vger.kernel.org, Pekka Enberg , iommu@lists.linux-foundation.org, Andrew Morton , Mel Gorman 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 On Wed, Dec 05, 2018 at 06:43:08AM -0800, Christoph Hellwig wrote: > On Wed, Dec 05, 2018 at 02:40:06PM +0000, Robin Murphy wrote: > > 32-bit Arm doesn't have ZONE_DMA32, but has (or at least had at the time) a > > 2GB ZONE_DMA. Whether we actually need that or not depends on how this all > > interacts with LPAE and highmem, but I'm not sure of those details off-hand. > > Well, arm32 can't address more than 32-bits in the linear kernel > mapping, so GFP_KERNEL should be perfectly fine there if the limit > really is 32-bits and not 31 or smaller because someone stole a bit > or two somewhere. I'm not sure that's necessarily true on the physical side. Wasn't there a keystone SoC with /all/ the coherent memory above 4GB? Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel