Memory Protection (Attributes)

[Gedare Bloom]

Hi Julien,

For safety you need memory protection to implement enforced isolation,
for example ARINC-653.

Another important factor is security, which becoming more important in
everyday computing devices. Nowadays control devices such as
SCADA-attached controllers, plant controllers (e.g. nuclear reactor
plants and stuxnet), automotive computers, medical devices, and so on
all have been shown vulnerable to attack and even had attacks surface
in the wild. Memory protection is one way to reduce the damage that
can be done if an attack succeeds, and can prevent some kinds of
attacks in general (e.g. buffer overflows).

Memory protection can also be useful for development/debugging, for
example if the hardware supports mapping page 0 without permissions
then NULL pointer dereferences can be caught faster, or isolating task
stacks can help detect if a stack blows and starts to write other
memory regions.

My suspicion is that most users would not need memory protection, but
there are definitely users who are interested in it (I know at least 2
developers are rolling their own already, not including me), so I felt
this is a good time to explore a general API for it.

-Gedare

On Mon, Dec 5, 2011 at 4:34 PM, Julien Delange <julien.delange at gmail.com> wrote:
> On Mon, Dec 5, 2011 at 9:30 PM, Thomas Doerfler > And I hope you will
> go on in this attempt, so don't get my partial
>> critics wrong. I think MP will be an important feature for realtime
>> systems in the future, so we need a proper, common, portable API in RTEMS.
>
> I am just wondering why you need memory protection in RTEMS. In
> general-purpose systems, I understand the need for safety/security.
> But I don't know if there is a strong need for application that would
> use RTEMS as a target platforn. Do you have an example of a system
> that will require such a service and how it would use it ?
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