Re: Contributing to OpenRISC Linux

[Stafford Horne <shorne@gmail.com>]

On Mon, Jan 13, 2025 at 11:42:08AM +0530, Sahil Siddiq wrote:
> Hi,
> 
> Thank you for your reply.
> 
> On 1/12/25 12:58 PM, Stafford Horne wrote:
> > Hi Sunil,
> > 
> > +CC List
> > 
> > yes, the cacheinfo task is still open.  There are many things that are still not
> > implemented in OpenRISC, you can always just look under the kernel
> > Documentation/features.
> > 
> > For example:
> > 
> >      < shorne@antec ~/work/linux > grep -r -e openrisc.*TODO Documentation/features | column -t
> >      Documentation/features/vm/huge-vmap/arch-support.txt:                |  openrisc:  |  TODO  |
> >      Documentation/features/vm/ELF-ASLR/arch-support.txt:                 |  openrisc:  |  TODO  |
> >      Documentation/features/vm/ioremap_prot/arch-support.txt:             |  openrisc:  |  TODO  |
> >      Documentation/features/vm/pte_special/arch-support.txt:              |  openrisc:  |  TODO  |
> >      Documentation/features/perf/kprobes-event/arch-support.txt:          |  openrisc:  |  TODO  |
> >      ...
> 
> Got it. I did find this list in the online documentation [1] but I couldn't find
> the cacheinfo task listed there.

Right, not all features have config flags that are documented.

Cacheinfo is implemented by overriding some weak symbols.

> > How far have you come with OpenRISC so far?  If you haven't already I suggest
> > working through:
> > 
> >   - Get a simulator, I use QEMU for most development as it's faster and supports
> >     more memory than most FPGA.  Final verification can be done on an FPGA.
> >   - Get a working compiler toolchain.
> >   - Compile and boot the openrisc kernel.
> >   - Build a userspace environment, either buildroot, toybox or busybox.
> > 
> > I have some tools to help with this in or1k-utils [1], also there are prebuilt
> > environments and docs in the linux kernel [2] and qemu [3].
> 
> I don't have an environment set up yet. I'll start with the steps above. I'll use
> QEMU for development. I don't have an FPGA with me currently.
> 
> > At the momoment, I am also thinking of what to work on next for OpenRISC, there is:
> > 
> >    - kexec
> >    - jump_label
> >    - kprobes
> >    - perf_events
> >    - ftrace
> 
> Is the virtio task [2] also still a part of the roadmap? I can't find that either
> in the TODO list.

The virtio task is still possible but will be more advanced and may need some
architecture changes to support hypervisors.

-Stafford

> > [1] https://github.com/stffrdhrn/or1k-utils
> > [2] https://docs.kernel.org/arch/openrisc/openrisc_port.html
> > [3] https://wiki.qemu.org/Documentation/Platforms/OpenRISC.
> > [...]
> 
> Thanks,
> Sahil
> 
> [1] https://docs.kernel.org/arch/openrisc/features.html
> [2] https://fossi-foundation.org/gsoc/gsoc24-ideas#openrisc-linux-feature-development
>