x86_64 BSP as GSOC2016 project

[Saket Sinha]

Hi Joel,

Thanks for your inputs.



On Wed, Feb 10, 2016 at 1:06 AM, Joel Sherrill <joel at rtems.org> wrote:
>
>
> On Tue, Feb 9, 2016 at 12:08 PM, Saket Sinha <saket.sinha89 at gmail.com>
> wrote:
>>
>> Hi,
>>
>> I think this is early for this but I need to enquire if x86_64_BSP (
>> https://devel.rtems.org/wiki/Developer/Projects/Open/x86_64_BSP )
>> could be taken as a GSOC project this year.
>>
>
> Yes. Assuming you mean the x86_64 bit port and accompanying BSP.
>
> If you noticed my post yesterday, we have tripped across a new embedded PC
> without legacy PCI BIOS support.
>

Could you provide the link. I am not able to locate it on mailing list
or your blog.

> Beyond the obvious port, for the purposes of your effort, there are
> a couple of bugs and some modernization needed by the pc386 BSP which
> you will likely have to address.
>
> + PCI BIOS uses legacy support. Needs to support new and old for 32-bit
> and new only for 64 bit.
> + Better APIC support. pc386 uses legacy PIC and some LPIC for SMP.
> Probably Ok for both 32 and 64 bit to support APIC only.
> + i386 does not have Thread Local Support. Both should have it.
> + i386 has a ticket for SMP synchronization during context switch.
> The code does not use atomics. Should be fixed and x86_64 follow the
> correct pattern.
>

So now my question is that could these be solved on an emulator like
qemu-x86, atleast for an initial POC ?
I mean is a x86_64 hardware required for it( though I have a Minnowmax board.)



> Basically x86_64 should assume a modern (non-legacy) PC and pc386
> needs updating to support newer systems. Common hardware platform
> so hopefully the software is standard.
>
> I was going to write this up as a "PC386 Modernization" Project but some
> of it makes sense as a side-effect of your project. That project idea also
> included killing AT bus NICs which you wouldn't have any reason to get
> near.
>
> You need a subtask list (e.g. todo list) and we need to help you flesh it
> out. I only hit a few non-obvious highlights.
>

Let me know how to dig deeper on this. Looking at the code, right  but
than exactly what sections ?


Regards,
Saket Sinha