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=-3.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 6150DC32754 for ; Wed, 7 Aug 2019 06:16:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2AA902086D for ; Wed, 7 Aug 2019 06:16:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="cqMrr/Gp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727105AbfHGGQY (ORCPT ); Wed, 7 Aug 2019 02:16:24 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:59020 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727078AbfHGGQX (ORCPT ); Wed, 7 Aug 2019 02:16:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: MIME-Version:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=rCYQCC3TGNYTbnGKL+NdUWUb7Cy3tCnvUbcf422Cqo8=; b=cqMrr/GpDS/ONJa2adLCzijXQ nhlDPhMwkhB8TMArgr+DXtiNpRuxaX4gIqfxBbgl2R2TMWBoHU7VjEkm6RgE/+hCjg1dpL5y5tNnn s81dLleKt6cPO7tG7ZK9StKoDepTYW/tT9J067lzaDoQk6auHE9prR7gJdA8jeIE8iAdNaUWoQLLx 5oI96/Ezmcy2PeCA7PjtVpiiBDbYQItbGaFbynb2bTc8fnQCF14c6deoNq/mqUscZaHFzLM2BsYZj FJlvl6Vl3KkD6RjJREk7K8QQlAh3eMZFXr+SckdnYDGTzmN798A2lIndyBa1/n1ZhMi6XMaJ5XCDf 9ggljiyAA==; Received: from [195.167.85.94] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1hvFEy-0007do-No; Wed, 07 Aug 2019 06:16:05 +0000 From: Christoph Hellwig To: iommu@lists.linux-foundation.org Cc: Shawn Anastasio , Michael Ellerman , Russell King , Catalin Marinas , Will Deacon , Robin Murphy , Paul Burton , James Hogan , linuxppc-dev@lists.ozlabs.org, linux-mips@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: fix default dma_mmap_* pgprot v3 Date: Wed, 7 Aug 2019 09:16:00 +0300 Message-Id: <20190807061602.31217-1-hch@lst.de> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Hi all, As Shawn pointed out we've had issues with the dma mmap pgprots ever since the dma_common_mmap helper was added beyong the initial architectures - we default to uncached mappings, but for devices that are DMA coherent, or if the DMA_ATTR_NON_CONSISTENT is set (and supported) this can lead to aliasing of cache attributes. This patch fixes that. My explanation of why this hasn't been much of an issue is that the dma_mmap_ helpers aren't used widely and mostly just in architecture specific drivers. Changes since v2: - fix m68knommu compile by inlining dma_prprot helper and providing a stub for !CONFIG_MMU - fix various typos in the commit messages Changes since v1: - fix handling of DMA_ATTR_NON_CONSISTENT where it is a no-op (which is most architectures) - remove DMA_ATTR_WRITE_COMBINE on mips, as it seem dangerous as-is