From patchwork Thu Nov 22 14:02:57 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 10694283 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 60F371709 for ; Thu, 22 Nov 2018 14:06:29 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 505422C2C3 for ; Thu, 22 Nov 2018 14:06:29 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4485F2CCD5; Thu, 22 Nov 2018 14:06:29 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.7 required=2.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C03A62C2C3 for ; Thu, 22 Nov 2018 14:06:28 +0000 (UTC) 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 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 X-Virus-Scanned: ClamAV using ClamSMTP 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