> On Sun, 8 Mar 2015 11:23 Tom Mitchell <[email protected]> wrote:
>>
>> On Sat, Mar 7, 2015 at 4:00 AM, Wolfgang Keller <[email protected]>
>> wrote:
>>>
>>> On Sat, Mar 7, 2015 at 6:18 AM, Sebastian Lau <[email protected]>
>>> wrote:
>>> > Would a port of seL4 to the raspberry pi 2 be welcome because I'm
>>> > interested
>>> > in buying a raspberry pi 2 and building sel4 for it?
>>>
>>> I have not much knowledge about seL4, but the boot process of the RPi
>>> (all versions) is rather special:
>>
>>
>> Thanks for the R-Pi summary!
>>
>> Some layers may be difficult to prove but that
>> should not make it impossible to do good work.
>>
>> Something along the lines...
>>     If Given: uboot is trusted.
>>     If Given: USB IO is trusted to devices ...UVW, XYZ.
>
>
> Obviously, it will not be possible to establish a chain of trust using uboot
> and USB. If a proof of correctness is the goal, don't even dream of doing it
> with the Raspberry Pi.

As I already told above: Even if we could trust uboot and some kind of
USB stack (IMHO complicated, but perhaps even doable), on RasPi, it's
the GPU that controls the CPU (as I told earlier). Thus you also have
to trust the firmware blob that contains an own OS running on the GPU
that is based on ThreadX. That's why I wrote

> Since the ARM core is just a slave to the GPU core which runs a binary
> blob based on ThreadX, this makes it IMHO very difficult to apply the
> correctness proof and guarantees of seL4 to the RPi version. If you
> can relinquish the correctness guarantees of seL4 (the thing that
> makes seL4 interesting) [...]

_______________________________________________
Devel mailing list
[email protected]
https://sel4.systems/lists/listinfo/devel

Reply via email to