From patchwork Tue Apr 25 17:57:39 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Catalin Marinas X-Patchwork-Id: 98224 Delivered-To: patch@linaro.org Received: by 10.140.109.52 with SMTP id k49csp2072021qgf; Tue, 25 Apr 2017 10:58:09 -0700 (PDT) X-Received: by 10.157.48.120 with SMTP id w53mr16107799otd.55.1493143089201; Tue, 25 Apr 2017 10:58:09 -0700 (PDT) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id a37si4582161ota.337.2017.04.25.10.58.08; Tue, 25 Apr 2017 10:58:09 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1952301AbdDYR6B (ORCPT + 10 others); Tue, 25 Apr 2017 13:58:01 -0400 Received: from foss.arm.com ([217.140.101.70]:45512 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1176770AbdDYR5v (ORCPT ); Tue, 25 Apr 2017 13:57:51 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 872741682; Tue, 25 Apr 2017 10:57:50 -0700 (PDT) Received: from e104818-lin.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 1C3783F4FF; Tue, 25 Apr 2017 10:57:48 -0700 (PDT) From: Catalin Marinas To: linux-kernel@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, geert@linux-m68k.org, a.hajda@samsung.com, robin.murphy@arm.com, Marek Szyprowski , Greg Kroah-Hartman , Russell King - ARM Linux Subject: [RFC PATCH] drivers: dma-mapping: Do not attempt to create a scatterlist for from_coherent buffers Date: Tue, 25 Apr 2017 18:57:39 +0100 Message-Id: <1493143059-2113-1-git-send-email-catalin.marinas@arm.com> X-Mailer: git-send-email 2.1.4 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Memory returned by dma_alloc_from_coherent() is not backed by struct page and creating a scatterlist would use invalid page pointers. The patch introduces the dma_vaddr_from_coherent() function and the corresponding check in dma_get_sgtable_attrs(). Fixes: d2b7428eb0ca ("common: dma-mapping: introduce dma_get_sgtable() function") Cc: Marek Szyprowski Cc: Greg Kroah-Hartman Cc: Russell King - ARM Linux Signed-off-by: Catalin Marinas --- In a recent discussion around the iommu DMA ops on arm64, Russell pointed out that dma_get_sgtable is not safe since the coherent DMA memory is not always backed by struct page. Russell has queued an arm-specific patch checking for pfn_valid() but I thought I'd make a more generic fix. This patch aims to bring the dma_get_sgtable() API in line with the dma_alloc/mmap/free with respect to the from_coherent memory. drivers/base/dma-coherent.c | 9 +++++++++ include/linux/dma-mapping.h | 5 +++++ 2 files changed, 14 insertions(+) diff --git a/drivers/base/dma-coherent.c b/drivers/base/dma-coherent.c index 640a7e63c453..1d2cdbefb850 100644 --- a/drivers/base/dma-coherent.c +++ b/drivers/base/dma-coherent.c @@ -279,6 +279,15 @@ int dma_mmap_from_coherent(struct device *dev, struct vm_area_struct *vma, } EXPORT_SYMBOL(dma_mmap_from_coherent); +int dma_vaddr_from_coherent(struct device *dev, void *vaddr, size_t size) +{ + struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL; + + return mem && vaddr >= mem->virt_base && + vaddr + size <= (mem->virt_base + (mem->size << PAGE_SHIFT)); +} +EXPORT_SYMBOL(dma_vaddr_from_coherent); + /* * Support for reserved memory regions defined in device tree */ diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index 0977317c6835..4dc99c6db184 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -164,10 +164,12 @@ int dma_release_from_coherent(struct device *dev, int order, void *vaddr); int dma_mmap_from_coherent(struct device *dev, struct vm_area_struct *vma, void *cpu_addr, size_t size, int *ret); +int dma_vaddr_from_coherent(struct device *dev, void *vaddr, size_t size); #else #define dma_alloc_from_coherent(dev, size, handle, ret) (0) #define dma_release_from_coherent(dev, order, vaddr) (0) #define dma_mmap_from_coherent(dev, vma, vaddr, order, ret) (0) +#define dma_vaddr_from_coherent(dev, vaddr, size) (0) #endif /* CONFIG_HAVE_GENERIC_DMA_COHERENT */ #ifdef CONFIG_HAS_DMA @@ -461,6 +463,9 @@ dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt, void *cpu_addr, { const struct dma_map_ops *ops = get_dma_ops(dev); BUG_ON(!ops); + /* dma_alloc_from_coherent() memory is not backed by struct page */ + if (dma_vaddr_from_coherent(dev, cpu_addr, size)) + return -ENXIO; if (ops->get_sgtable) return ops->get_sgtable(dev, sgt, cpu_addr, dma_addr, size, attrs);