From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mailout4.samsung.com ([203.254.224.34]:32611 "EHLO mailout4.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753971Ab2JBOa3 (ORCPT ); Tue, 2 Oct 2012 10:30:29 -0400 Received: from epcpsbgm2.samsung.com (epcpsbgm2 [203.254.230.27]) by mailout4.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0MB900EV3SA0IC00@mailout4.samsung.com> for linux-media@vger.kernel.org; Tue, 02 Oct 2012 23:30:28 +0900 (KST) Received: from mcdsrvbld02.digital.local ([106.116.37.23]) by mmp2.samsung.com (Oracle Communications Messaging Server 7u4-24.01 (7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTPA id <0MB9005A7S65K790@mmp2.samsung.com> for linux-media@vger.kernel.org; Tue, 02 Oct 2012 23:30:28 +0900 (KST) From: Tomasz Stanislawski To: linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org Cc: airlied@redhat.com, m.szyprowski@samsung.com, t.stanislaws@samsung.com, kyungmin.park@samsung.com, laurent.pinchart@ideasonboard.com, sumit.semwal@ti.com, daeinki@gmail.com, daniel.vetter@ffwll.ch, robdclark@gmail.com, pawel@osciak.com, linaro-mm-sig@lists.linaro.org, hverkuil@xs4all.nl, remi@remlab.net, subashrp@gmail.com, mchehab@redhat.com, zhangfei.gao@gmail.com, s.nawrocki@samsung.com, k.debski@samsung.com Subject: [PATCHv9 22/25] v4l: vb2-dma-contig: fail if user ptr buffer is not correctly aligned Date: Tue, 02 Oct 2012 16:27:33 +0200 Message-id: <1349188056-4886-23-git-send-email-t.stanislaws@samsung.com> In-reply-to: <1349188056-4886-1-git-send-email-t.stanislaws@samsung.com> References: <1349188056-4886-1-git-send-email-t.stanislaws@samsung.com> Sender: linux-media-owner@vger.kernel.org List-ID: From: Marek Szyprowski The DMA transfer must be aligned to a specific value. If userptr is not aligned to DMA requirements then unexpected corruptions of the memory may occur before or after a buffer. To prevent such situations, all unligned userptr buffers are rejected at VIDIOC_QBUF. Signed-off-by: Marek Szyprowski --- drivers/media/video/videobuf2-dma-contig.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/media/video/videobuf2-dma-contig.c b/drivers/media/video/videobuf2-dma-contig.c index b4d287a..55f8c80 100644 --- a/drivers/media/video/videobuf2-dma-contig.c +++ b/drivers/media/video/videobuf2-dma-contig.c @@ -494,6 +494,13 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr, struct vm_area_struct *vma; struct sg_table *sgt; unsigned long contig_size; + unsigned long dma_align = dma_get_cache_alignment(); + + /* Only cache aligned DMA transfers are reliable */ + if (!IS_ALIGNED(vaddr | size, dma_align)) { + pr_err("user data must be aligned to %lu bytes\n", dma_align); + return ERR_PTR(-EINVAL); + } buf = kzalloc(sizeof *buf, GFP_KERNEL); if (!buf) -- 1.7.9.5