Re: [PATCH v11 03/11] firmware: xilinx: Add zynqmp IOCTL API for device control

From: Moritz Fischer
Date: Sun Sep 09 2018 - 15:20:13 EST

Hi Olof,

On Sat, Sep 8, 2018 at 6:18 PM, Olof Johansson <olof@xxxxxxxxx> wrote:
> Hi,
> On Fri, Aug 3, 2018 at 10:53 AM, Jolly Shah <jolly.shah@xxxxxxxxxx> wrote:
>> From: Rajan Vaja <rajanv@xxxxxxxxxx>
>> Add ZynqMP firmware IOCTL API to control and configure
>> devices like PLLs, SD, Gem, etc.
>> Signed-off-by: Rajan Vaja <rajanv@xxxxxxxxxx>
>> Signed-off-by: Jolly Shah <jollys@xxxxxxxxxx>
> This patch worries me somewhat. It's a transparent pass-through ioctl
> driver. Is there a spec available for what the implemented IOCTLs are?
> Should some of them be proper drivers instead of an opaque
> pass-through like this? Could some of them have stability impact on
> the platform such that there are security concerns and the list of
> arguments should somehow be sanitized?

I tend to agree with this, good catch.

> What's the intended usecase anyway? Just a debug tool during
> development, or something that you expect heavy use of by some
> userspace middleware?

I suspect it is another attempt to make userspace clocks/plls work? Scary.