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=-8.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 01256C43441 for ; Thu, 22 Nov 2018 14:06:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BB90820684 for ; Thu, 22 Nov 2018 14:06:28 +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="VBeO4MUy" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BB90820684 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-parisc-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2395324AbeKWAnF (ORCPT ); Thu, 22 Nov 2018 19:43:05 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:54716 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388851AbeKWAnF (ORCPT ); Thu, 22 Nov 2018 19:43:05 -0500 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:References:In-Reply-To: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:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=MtJ8xWA9qUHloLCvIEk/FO/K2KiiWlRZFAUGaRfluEU=; b=VBeO4MUyZpT6Uz3BAJpXDOk8Uo /FRVCIk1A14IplUDrLhOK/gb7SBRYL4RerbmU9plQ3LHIcmmN4tyiGNuJbB9rz7dJKxSpUS0GHIN1 Kphn/TXjf55Olgpc9jNDFR+ufftxyVdLXH7aygV7C9ZJ4ZQcFpK8RXniWYx/H/Gw74hoXFLadGVJi kPk3z49co61r2z/69Xf+Kwnt0CCYu8afTmAvS2HCKXnUfGAMsWPWbfq1SlkVW17aNYEFT2KzbIysg iKoBMFEDulX4iK3g+vTgOhytNYv72XKVdeSZZYSb9qDXmS/znUupeKXJbpLTBYBVKsmSqsvvdz1pu 1U2moY4Q==; Received: from clnet-p19-102.ikbnet.co.at ([83.175.77.102] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gPpZn-0007Wm-1w; Thu, 22 Nov 2018 14:03:27 +0000 From: Christoph Hellwig To: iommu@lists.linux-foundation.org Cc: Linus Torvalds , Jon Mason , Joerg Roedel , David Woodhouse , Marek Szyprowski , Robin Murphy , x86@kernel.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linux-parisc@vger.kernel.org, xen-devel@lists.xenproject.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 01/24] dma-direct: Make DIRECT_MAPPING_ERROR viable for SWIOTLB Date: Thu, 22 Nov 2018 15:02:57 +0100 Message-Id: <20181122140320.24080-2-hch@lst.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181122140320.24080-1-hch@lst.de> References: <20181122140320.24080-1-hch@lst.de> 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-parisc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org From: Robin Murphy With the overflow buffer removed, we no longer have a unique address which is guaranteed not to be a valid DMA target to use as an error token. The DIRECT_MAPPING_ERROR value of 0 tries to at least represent an unlikely DMA target, but unfortunately there are already SWIOTLB users with DMA-able memory at physical address 0 which now gets falsely treated as a mapping failure and leads to all manner of misbehaviour. The best we can do to mitigate that is flip DIRECT_MAPPING_ERROR to the other commonly-used error value of all-bits-set, since the last single byte of memory is by far the least-likely-valid DMA target. Fixes: dff8d6c1ed58 ("swiotlb: remove the overflow buffer") Reported-by: John Stultz Tested-by: John Stultz Acked-by: Konrad Rzeszutek Wilk Signed-off-by: Robin Murphy Signed-off-by: Christoph Hellwig --- include/linux/dma-direct.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h index bd73e7a91410..9e66bfe369aa 100644 --- a/include/linux/dma-direct.h +++ b/include/linux/dma-direct.h @@ -5,7 +5,7 @@ #include #include -#define DIRECT_MAPPING_ERROR 0 +#define DIRECT_MAPPING_ERROR (~(dma_addr_t)0) #ifdef CONFIG_ARCH_HAS_PHYS_TO_DMA #include -- 2.19.1