Hello Thomas. > -----Original Message----- > From: Thomas Hellstrom [mailto:thomas@xxxxxxxxxxxx] > Sent: Wednesday, August 31, 2011 5:39 PM > To: Inki Dae > Cc: airlied@xxxxxxxx; dri-devel@xxxxxxxxxxxxxxxxxxxxx; > sw0312.kim@xxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > kyungmin.park@xxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > Subject: Re: [RFC][PATCH v3] DRM: add DRM Driver for Samsung SoC > EXYNOS4210. > > 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 > Right, we should consider security issue also as you mentioned above. thank you for your pointing out. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
