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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 0DE66C5DF60 for ; Thu, 7 Nov 2019 15:07:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E255A21D79 for ; Thu, 7 Nov 2019 15:07:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388828AbfKGPHJ (ORCPT ); Thu, 7 Nov 2019 10:07:09 -0500 Received: from mx2.suse.de ([195.135.220.15]:55328 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729450AbfKGPHJ (ORCPT ); Thu, 7 Nov 2019 10:07:09 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 84B61B258; Thu, 7 Nov 2019 15:07:07 +0000 (UTC) From: Nicolas Saenz Julienne To: rubini@gnudd.com, hch@infradead.org, linux-kernel@vger.kernel.org, Christoph Hellwig , Marek Szyprowski , Robin Murphy Cc: Nicolas Saenz Julienne , iommu@lists.linux-foundation.org Subject: [PATCH v3 1/2] dma-direct: check for overflows on 32 bit DMA addresses Date: Thu, 7 Nov 2019 16:06:44 +0100 Message-Id: <20191107150646.13485-2-nsaenzjulienne@suse.de> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191107150646.13485-1-nsaenzjulienne@suse.de> References: <20191107150646.13485-1-nsaenzjulienne@suse.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- Changes since v2: - Cleanup code: use IS_ENABLED, a tmp variable for end, and use phys_to_dma(). include/linux/dma-direct.h | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h index adf993a3bd58..6a18a97b76a8 100644 --- a/include/linux/dma-direct.h +++ b/include/linux/dma-direct.h @@ -3,8 +3,11 @@ #define _LINUX_DMA_DIRECT_H 1 #include +#include /* for min_low_pfn */ #include +static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr); + #ifdef CONFIG_ARCH_HAS_PHYS_TO_DMA #include #else @@ -24,11 +27,16 @@ static inline phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t dev_addr) static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size) { + dma_addr_t end = addr + size - 1; + if (!dev->dma_mask) return false; - return addr + size - 1 <= - min_not_zero(*dev->dma_mask, dev->bus_dma_mask); + if (!IS_ENABLED(CONFIG_ARCH_DMA_ADDR_T_64BIT) && + min(addr, end) < phys_to_dma(dev, PFN_PHYS(min_low_pfn))) + return false; + + return end <= min_not_zero(*dev->dma_mask, dev->bus_dma_mask); } #endif /* !CONFIG_ARCH_HAS_PHYS_TO_DMA */ -- 2.23.0