Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966481AbaFSX7q (ORCPT ); Thu, 19 Jun 2014 19:59:46 -0400 Received: from mail-lb0-f176.google.com ([209.85.217.176]:41661 "EHLO mail-lb0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965771AbaFSX7o (ORCPT ); Thu, 19 Jun 2014 19:59:44 -0400 Date: Fri, 20 Jun 2014 02:59:38 +0300 From: Siarhei Siamashka To: Daniel Kurtz Cc: Inki Dae , dri-devel@lists.freedesktop.org, Kukjin Kim , Seung-Woo Kim , linux-kernel@vger.kernel.org, Kyungmin Park , linux-samsung-soc@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 1/2] drm/exynos/fbdev: don't set fix.smem/mmio_{start,len} Message-ID: <20140620025938.2e80efa0@i7> In-Reply-To: <1396603322-13585-1-git-send-email-djkurtz@chromium.org> References: <1396603322-13585-1-git-send-email-djkurtz@chromium.org> X-Mailer: Claws Mail 3.9.0 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 4 Apr 2014 17:22:01 +0800 Daniel Kurtz wrote: > Kernel access to the eyxnos fbdev framebuffer is via its gem object's > kernel mapping (kvaddr, stored in info->screen_base). > > User space access is provided by mmap(), read() and write() of /dev/fb/fb0. > These functions also only use screen_base/screen_size(). > > Therefore, it is not necessary to set fix->smem_{start,len} or > fix->mmio_{start,len} fields. > > This avoids leaking kernel, physical and dma mapped addresses to user > space via the ioctls FBIOGET_VSCREENINFO and FBIOGET_FSCREENINFO. > > Signed-off-by: Daniel Kurtz > --- > drivers/gpu/drm/exynos/exynos_drm_fbdev.c | 7 ------- > 1 file changed, 7 deletions(-) > > diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c > index 5fa342e..2dcc589 100644 > --- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c > +++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c > @@ -123,14 +123,7 @@ static int exynos_drm_fbdev_update(struct drm_fb_helper *helper, > > dev->mode_config.fb_base = (resource_size_t)buffer->dma_addr; > fbi->screen_base = buffer->kvaddr + offset; > - if (is_drm_iommu_supported(dev)) > - fbi->fix.smem_start = (unsigned long) > - (page_to_phys(sg_page(buffer->sgt->sgl)) + offset); > - else > - fbi->fix.smem_start = (unsigned long)buffer->dma_addr; > - > fbi->screen_size = size; > - fbi->fix.smem_len = size; Can we keep proper initialization of 'smem_len'? Some userland applications use it for calculating the size for mmap: http://cgit.freedesktop.org/xorg/xserver/tree/hw/xfree86/fbdevhw/fbdevhw.c?id=xorg-server-1.15.99.903#n571 > > return 0; > } Basically, this patch breaks the xf86-video-fbdev ddx and some users are already unhappy. -- Best regards, Siarhei Siamashka -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/