Re: [PATCH v2 09/14] drm/exynos: add G2D driver

[Joonyoung Shim <jy0922.shim@samsung.com>]

On 03/19/2012 09:25 PM, Dave Airlie wrote:
> On Fri, Mar 16, 2012 at 9:47 AM, Inki Dae<inki.dae@samsung.com>  wrote:
>> From: Joonyoung Shim<jy0922.shim@samsung.com>
>>
>> The G2D is a 2D graphic accelerator that supports Bit Block Transfer.
>> This G2D driver is exynos drm specific and supports only G2D(version
>> 4.1) of later Exynos series from Exynos4X12 because supporting DMA.
> So just to make sure I understand, userspace generates two command
> streams, one containing registers that don't need base addresses
> and one containing registers that do contain it.
>
> Now tell me how this address security wise, since non-root users have
> the ability to use this interface.
>
> can userspace put registers that require a base address into the first
> command stream and specify any phy addr in the system?

Right, it's possible scenario. I will add codes to check it.

> If not, please
> explain in comments where this is blocked. Where is the list of
> registers the first command stream and second command stream can
> access specified?
>
> I'm not really happy about this appearing so late on the radar for
> 3.4, you really want new major userspace security features to turn up
> a lot earlier for review.

I post the patch to get the review like this and i think time posting
patch can be open always. If the patch has serious problem, certainly
don't apply it. I don't want it too, but i will try to solve it and
resend updated patch.

Thanks.