Re: 2026 TODO list!

Nice to meet you all!,
I would like to join the team to maintain PPC/PPC64 for development and testing.

The good:
I have a G5 Quad, an XServe G5, and a Dual G4 @ 500, so I think I have a "decent" coverage surface.

The bad:
Aside from the G4, both G5s need maintenance before I can keep them running for hours, I'm on top of that, but it's gonna take a while.

The ugly:
I have development  (kernel / userspace) experience on Linux, but on FBSD I'm mostly relegated to userspace at the moment.

I want to change that; I'd like to have robust knowledge for kernel and driver development on FBSD for PPC/x86. That's why I am here.

Questions:
- What is the best technique for kernel debugging on FBSD? (please don't say printf :D). Does remote GDB over serial work? I've read about KDBG but I'm not sure which approach is better.

- Has anybody tested on QEmu some sort of paravirtualization running on G4/G5, so we don't need to go baremetal all the time when doing kernel development?

Sorry for the long email!

Kind Regards,
Javi.





On January 13, 2026 9:27:05 PM UTC, Timothy Pearson <tpearson@raptorengineering.com> wrote:
>
>
>----- Original Message -----
>> From: "Lexi Winter" <ivy@freebsd.org>
>> To: "freebsd-ppc" <freebsd-ppc@freebsd.org>
>> Sent: Tuesday, January 13, 2026 3:42:28 AM
>> Subject: Re: 2026 TODO list!
>
>> Adrian Chadd wrote in
>> <CAJ-VmonYHdVhdPiaLHUqzPv33_iAGiTY=_hGrhg4rXF5+YZPQQ@mail.gmail.com>:
>>> I'd like to assemble a 2026 TODO list for PPC64 work. Justin, Ivy,
>>> Warner, I and and others have been poking at the sharp edges and
>>> trying to use/abuse various PPC64 hardware and VMs.
>>> 
>>> I'd appreciate some brainstorming from y'all about what you'd like to
>>> see fixed, implemented and working.
>> 
>> i've been meaning to look at making lldb work on powerpc64le for both
>> kernel and userland debugging.  this looks like it should be pretty
>> simple, since it already supports FreeBSD/ppc64 and Linux/ppc64le,
>> so it's just a matter of combining the two.
>> 
>> i've been busy with non-FreeBSD stuff recently but i'm hoping i can
>> look at this soon.
>> 
>> Raptor has kindly given me access to a Talos II so i can do dev work
>> and also test patches there if needed.
>> 
>> a couple of other things i think are important:
>> 
>> - non-OpenFirmware ppc64le loader - i see a couple of people have
>>  already mentioned this.
>> 
>> - SMP performance is quite bad; this 44-core SMT4 Talos II runs
>>  buildworld at the same speed as my 8-core 2.6GHz Xeon system.
>>  i mentioned this to Justin and he suspects this could be from
>>   locking issues in vm/pmap.
>
>After digging around in the PCI driver for the past month, I think we're also not getting DMA enabled on potentially *any* PCI devices.  It looks like the DMA tag was removed for PHB4 (POWER9) support, but it might have worked on PHB3 (POWER8).  Once I finish fixing the rest of the PE 1:1 mapping mess I'll start looking at that and see if we can't get DMA reenabled -- no DMA would definitely explain poor performance on disk intensive activity...
>