GSoC project: Memory protection (Ticket no: 2904)

[Hesham Almatary]

Hello Rajiv,

The project is a bit advanced. To be able to use MMU, RTEMS has to be
ported to RISC-V's S-Mode. I created a ticket for that a few years ago
[1]. This needs a decent understanding of RISC-V and non-trivial
efforts to refactor RTEMS and its exception/interrupt handling,
context-switching, emulation layers and calls to M-Mode, etc. I am not
sure that (porting to S-Mode and supporting MMU) could fit in a GSoC
project.

[1] https://devel.rtems.org/ticket/3337

On Fri, 26 Mar 2021 at 12:25, Rajiv Vaidyanathan
<rajiv.vaidyanathan4 at gmail.com> wrote:
>
> Dear Hesham,
>
> Thank you for providing information about the RISC-V MMU. I want to know what work has to be done in improving MMU in RISC-V and if it can be a GSoC project. It would be great if you could provide the details regarding this.
>
> Thanks and regards,
> Rajiv
>
> On Wed, 24 Mar 2021 at 00:03, Hesham Almatary <hesham.almatary at cl.cam.ac.uk> wrote:
>>
>> On Tue, 23 Mar 2021 at 17:14, Gedare Bloom <gedare at rtems.org> wrote:
>> >
>> > CC: Hesham
>> > CC: devel
>> >
>> > On Tue, Mar 23, 2021 at 6:34 AM Rajiv Vaidyanathan
>> > <rajiv.vaidyanathan4 at gmail.com> wrote:
>> > >
>> > > Dear Gedare,
>> > >
>> > > Thank you for providing information regarding the project. For risk-v MMU support, will I require to have hardware?
>> > >
>> > That's a good question. I don't know if the current risc-v simulators
>> > support the risc-v mmu. maybe, another expert could advise. I have
>> > CC'd someone with experience in both risc-v and memory protection.
>> >
>> Yes, both Spike and QEMU have MMU and PMP support.
>>
>> > Let's keep technical discussions on the mailing list. Thanks.
>> >
>> > > Thanks and regards,
>> > > Rajiv
>> > >
>> > > On Mon, 22 Mar 2021 at 21:54, Gedare Bloom <gedare at rtems.org> wrote:
>> > >>
>> > >> Hi Rajiv,
>> > >>
>> > >> On Sat, Mar 20, 2021 at 12:40 AM Rajiv Vaidyanathan
>> > >> <rajiv.vaidyanathan4 at gmail.com> wrote:
>> > >> >
>> > >> > Hello RTEMS community,
>> > >> >
>> > >> > I am interested in the ticket: Memory protection. I saw that this topic has been pursued a few times in GSoC. It would be great if someone can let me know the current status of this project and guide me about what are the contributions that can be done this year.
>> > >> >
>> > >> Yes, this is a frequently attempted project that slowly makes progress
>> > >> over time. I think that Utkarsh has gotten somewhat close to a
>> > >> workable solution, but there were some design flaws in his approach
>> > >> for task stack protection (mainly, iterating over all the tasks) that
>> > >> are still lingering.
>> > >>
>> > >> There could be enough work here to pick up from his progress. The
>> > >> major issue would be figuring out what  the final state of his code is
>> > >> in, and to dig in to the design and implementation details to write a
>> > >> concrete proposal how to bring task stack protection to a production
>> > >> state. There may be other directions to consider as well, such as
>> > >> improving the risc-v MMU support perhaps.
>> > >>
>> > >> > Thanks and regards,
>> > >> > Rajiv
>> > >> > _______________________________________________
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>> > >> > devel at rtems.org
>> > >> > http://lists.rtems.org/mailman/listinfo/devel
>> > _______________________________________________
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