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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 721B1C5DF60 for ; Tue, 5 Nov 2019 16:29:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4D4B72087E for ; Tue, 5 Nov 2019 16:29:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390210AbfKEQ3A (ORCPT ); Tue, 5 Nov 2019 11:29:00 -0500 Received: from verein.lst.de ([213.95.11.211]:46395 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390137AbfKEQ3A (ORCPT ); Tue, 5 Nov 2019 11:29:00 -0500 Received: by verein.lst.de (Postfix, from userid 2407) id D251368AFE; Tue, 5 Nov 2019 17:28:56 +0100 (CET) Date: Tue, 5 Nov 2019 17:28:56 +0100 From: Christoph Hellwig To: Christian Zigotzky Cc: Christoph Hellwig , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, Olof Johansson Subject: Re: Bug 205201 - overflow of DMA mask and bus mask Message-ID: <20191105162856.GA15402@lst.de> References: <20181213112511.GA4574@lst.de> <008c981e-bdd2-21a7-f5f7-c57e4850ae9a@xenosoft.de> <20190103073622.GA24323@lst.de> <71A251A5-FA06-4019-B324-7AED32F7B714@xenosoft.de> <1b0c5c21-2761-d3a3-651b-3687bb6ae694@xenosoft.de> <3504ee70-02de-049e-6402-2d530bf55a84@xenosoft.de> <46025f1b-db20-ac23-7dcd-10bc43bbb6ee@xenosoft.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <46025f1b-db20-ac23-7dcd-10bc43bbb6ee@xenosoft.de> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 05, 2019 at 08:56:27AM +0100, Christian Zigotzky wrote: > Hi All, > > We still have DMA problems with some PCI devices. Since the PowerPC updates > 4.21-1 [1] we need to decrease the RAM to 3500MB (mem=3500M) if we want to > work with our PCI devices. The FSL P5020 and P5040 have these problems > currently. > > Error message: > > [   25.654852] bttv 1000:04:05.0: overflow 0x00000000fe077000+4096 of DMA > mask ffffffff bus mask df000000 > > All 5.x Linux kernels can't initialize a SCSI PCI card anymore so booting > of a Linux userland isn't possible. > > PLEASE check the DMA changes in the PowerPC updates 4.21-1 [1]. The kernel > 4.20 works with all PCI devices without limitation of RAM. Can you send me the .config and a dmesg? And in the meantime try the patch below? --- >From 4d659b7311bd4141fdd3eeeb80fa2d7602ea01d4 Mon Sep 17 00:00:00 2001 From: Nicolas Saenz Julienne Date: Fri, 18 Oct 2019 13:00:43 +0200 Subject: dma-direct: check for overflows on 32 bit DMA addresses As seen on the new Raspberry Pi 4 and sta2x11's DMA implementation it is possible for a device configured with 32 bit DMA addresses and a partial DMA mapping located at the end of the address space to overflow. It happens when a higher physical address, not DMAable, is translated to it's DMA counterpart. For example the Raspberry Pi 4, configurable up to 4 GB of memory, has an interconnect capable of addressing the lower 1 GB of physical memory with a DMA offset of 0xc0000000. It transpires that, any attempt to translate physical addresses higher than the first GB will result in an overflow which dma_capable() can't detect as it only checks for addresses bigger then the maximum allowed DMA address. Fix this by verifying in dma_capable() if the DMA address range provided is at any point lower than the minimum possible DMA address on the bus. Signed-off-by: Nicolas Saenz Julienne --- include/linux/dma-direct.h | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h index adf993a3bd58..6ad9e9ea7564 100644 --- a/include/linux/dma-direct.h +++ b/include/linux/dma-direct.h @@ -3,6 +3,7 @@ #define _LINUX_DMA_DIRECT_H 1 #include +#include /* for min_low_pfn */ #include #ifdef CONFIG_ARCH_HAS_PHYS_TO_DMA @@ -27,6 +28,13 @@ static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size) if (!dev->dma_mask) return false; +#ifndef CONFIG_ARCH_DMA_ADDR_T_64BIT + /* Check if DMA address overflowed */ + if (min(addr, addr + size - 1) < + __phys_to_dma(dev, (phys_addr_t)(min_low_pfn << PAGE_SHIFT))) + return false; +#endif + return addr + size - 1 <= min_not_zero(*dev->dma_mask, dev->bus_dma_mask); } -- 2.20.1