From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753977Ab1HaI52 (ORCPT ); Wed, 31 Aug 2011 04:57:28 -0400 Received: from ns2.gothnet.se ([82.193.160.251]:2245 "EHLO GOTHNET-SMTP2.gothnet.se" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750779Ab1HaI5Z (ORCPT ); Wed, 31 Aug 2011 04:57:25 -0400 X-Greylist: delayed 986 seconds by postgrey-1.27 at vger.kernel.org; Wed, 31 Aug 2011 04:57:25 EDT Message-ID: <4E5DF323.9020509@shipmail.org> Date: Wed, 31 Aug 2011 10:38:59 +0200 From: Thomas Hellstrom User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.10) Gecko/20100624 Mandriva/3.0.5-0.1mdv2009.1 (2009.1) Thunderbird/3.0.5 MIME-Version: 1.0 To: Inki Dae CC: airlied@linux.ie, dri-devel@lists.freedesktop.org, sw0312.kim@samsung.com, linux-kernel@vger.kernel.org, kyungmin.park@samsung.com, linux-arm-kernel@lists.infradead.org Subject: Re: [RFC][PATCH v3] DRM: add DRM Driver for Samsung SoC EXYNOS4210. References: <1314359274-21585-1-git-send-email-inki.dae@samsung.com> In-Reply-To: <1314359274-21585-1-git-send-email-inki.dae@samsung.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-BitDefender-Scanner: Mail not scanned due to license constraints Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/26/2011 01:47 PM, Inki Dae wrote: > This patch is a DRM Driver for Samsung SoC Exynos4210 and now enables only FIMD yet > but we will add HDMI support also in the future. > > this patch is based on git repository below: > git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6.git, > branch name: drm-next > commit-id: bcc65fd8e929a9d9d34d814d6efc1d2793546922 > > you can refer to our working repository below: > http://git.infradead.org/users/kmpark/linux-2.6-samsung > branch name: samsung-drm > > We tried to re-use lowlevel codes of the FIMD driver(s3c-fb.c > based on Linux framebuffer) but couldn't so because lowlevel codes > of s3c-fb.c are included internally and so FIMD module of this driver has > its own lowlevel codes. > > We used GEM framework for buffer management and DMA APIs(dma_alloc_*) > for buffer allocation. by using DMA API, we could use CMA later. > > Refer to this link for CMA(Continuous Memory Allocator): > http://lkml.org/lkml/2011/7/20/45 > > this driver supports only physically continuous memory(non-iommu). > > Links to previous versions of the patchset: > v1:< https://lwn.net/Articles/454380/> > v2:< http://www.spinics.net/lists/kernel/msg1224275.html> > > Changelog v2: > DRM: add DRM_IOCTL_SAMSUNG_GEM_MMAP ioctl command. > > this feature maps user address space to physical memory region > once user application requests DRM_IOCTL_SAMSUNG_GEM_MMAP ioctl. > > DRM: code clean and add exception codes. > > Changelog v3: > DRM: Support multiple irq. > > FIMD and HDMI have their own irq handler but DRM Framework can regiter only one irq handler > this patch supports mutiple irq for Samsung SoC. > > DRM: Consider modularization. > > each DRM, FIMD could be built as a module. > > DRM: Have indenpendent crtc object. > > crtc isn't specific to SoC Platform so this patch gets a crtc to be used as common object. > created crtc could be attached to any encoder object. > > DRM: code clean and add exception codes. > > S > ... > +static struct drm_ioctl_desc samsung_ioctls[] = { > + DRM_IOCTL_DEF_DRV(SAMSUNG_GEM_CREATE, samsung_drm_gem_create_ioctl, > + DRM_UNLOCKED), > + DRM_IOCTL_DEF_DRV(SAMSUNG_GEM_MAP_OFFSET, > + samsung_drm_gem_map_offset_ioctl, DRM_UNLOCKED), > + DRM_IOCTL_DEF_DRV(SAMSUNG_GEM_MMAP, > + samsung_drm_gem_mmap_ioctl, DRM_UNLOCKED), > +}; > What about security here? It looks to me like *any* user-space process can create a gem object and quickly exhaust available DMA memory space, potentially bringing the system down? Likewise, there seems to be no owner check in the SAMSUNG_GEM_MMAP ioctl, allowing any user-space process unlimited graphics buffer access? /Thomas