Memory Protection (Attributes)

[Chris Johns]

On 6/12/11 5:52 AM, Gedare Bloom wrote:
>
> Hi,
> I am working to bring primitives for real-time memory protection to
> RTEMS, and as a first step I have designed a solution for
> setting/enforcing attributes on memory regions.

Many thanks for taking on this project. It is a valuable contribution to 
RTEMS.

  The design is in three
> layers: a high-level API (cpukit) layer, a middle layer for CPU family
> support (libcpu), and a low-level layer for hardware-specific support
> (libcpu/libbsp).
>
> I have written a description of the API layer [1] and would appreciate
> any feedback. I prefer to have the feedback given publicly to the
> rtems-devel mailing list (or privately to me directly).

We need some terms to help discuss this topic ("use case" not being 
one). I have been playing with 'arenas' as a term. That is "Memory 
Protection Arenas". To try and define it ....

  Memory Protection Arenas

   "A construct with specific memory attributes that can be shared
    amongst tasks."

A Memory Protection Arena is a piece of memory with a descriptor where 
some attributes have been set to control the behavior of the memory 
area, and executing contexts given access to the memory area. Tasks can 
access arenas in a many to one relationship and can be part of more than 
one arena.

I hope that made sense.

Chris