[sw-dev] Re: Project proposal: RISC-V port

Bruce Hoult bruce at hoult.org
Tue Feb 13 18:49:38 UTC 2018

It would be a really good thing to have one or more EC2 AMIs available that
people could just spin up on whatever instance they want and it puts them
into an emulated RISC-V Linux environment. Preferably taking advantage of
all the available cores. User mode qemu with a chroot and binfmt_misc could
be made to work right now, and full system qemu when that supports multiple
cores. Or RV8 if that gets more syscalls implemented.

And/or Docker.

I'd be happy to set that kind of thing up once I get freed up to work on
RISC-V stuff full time.

On Tue, Feb 13, 2018 at 9:41 PM, Palmer Dabbelt <palmer at dabbelt.com> wrote:

> On Fri, 09 Feb 2018 02:57:21 PST (-0800), edward.nevill at gmail.com wrote:
>> Hi,
>> I would like to voice my support for the creation of this project.
>> The process for creation of a new OpenJDK project is described at
>> http://openjdk.java.net/projects/#new-project
>> The initial discussion should be sent to the general discussion list,
>> discuss.at.openjdk.dot.java.dot.net. I have cc'd this to the general
>> discussion list.
> Thanks.
> Assuming that the group lead of the porters project agrees to sponsor the
>> project then the call for votes should be sent to
>> announce.at.openjdk.dot.java.dot.net.
>> Note that only current OpenJDK contributors may propose the creation of a
>> new project. If you are not a current OpenJDK contributor I am happy to
>> propose the project on your behalf.
> We never submitted the Tilera port, so I'm not a contributor at all.  It
> would be great if you could propose the project for me.
> http://openjdk.java.net/bylaws#contributor
>> I am happy to devote some 'spare' time to this project, but this will me
>> limited to a few hours per week.
> Well, that's about all the time I'll have as well :).  I know that OpenJDK
> is way more work than a spare time project, but I'm hoping that we can at
> least get things started with a community effort and then see where things
> go from there.
> I agree with the overall approach you outline below. You will probably end
>> up doing C1 anyway. The s390 port tried to do it without doing C1 and they
>> ended up doing C1.
>> Andrew Haley's suggestion of using a built in simulator is a good one.
>> This was the approach used on the aarch64 project and it was invaluable
>> not just in terms of development time in the absence of hardware but in
>> terms of debuggability. Also OpenJDK depends on a huge list of packages to
>> build. Using this approach you can build and run on x86 while all the
>> dependant packages are being ported.
> That makes sense.  IIRC there were a lot of headaches involved in getting
> this all together last time, and having a simulator seems like a good idea.
>> All the best,
>> Ed.
>> On Thu, 2018-02-08 at 08:38 -0800, Palmer Dabbelt wrote:
>>> [Sorry for the second email, it appears my SiFive email doesn't want to
>>> subscribe to porters-dev.]
>>> RISC-V is an open standard ISA stewarded by the RISC-V foundation
>>> <http://riscv.org>.  With the recent release of glibc 2.27 we now have
>>> the full
>>> RISC-V software base released from the various upstream repositories,
>>> which
>>> means it's time to start moving forward with the rest of the software
>>> stack.  I
>>> ran into Erik at FOSDEM a few days ago and he suggested that we open up
>>> the
>>> discussion of an OpenJDK port for RISC-V.  While I'm not familiar with
>>> the
>>> RISC-V Java efforts, I did part of a Hotspot port (a bit of the template
>>> interpreter and much of C2) to Tilera's TilePro and TileGx architectures
>>> a few
>>> years ago so I know a bit about the OpenJDK internals.
>>> In the RISC-V community we view Java as a very important missing
>>> component of
>>> the software ecosystem, so I was thrilled when Erik found me at FOSDMEM
>>> and
>>> suggested there was community interest in a port.  Unfortunately, I
>>> won't have
>>> time to properly help out with the port (I'm maintaining Linux, as well
>>> as
>>> co-maintaining binutils, GCC, and glibc).  That said, I'd be very happy
>>> to help
>>> out where I can.  I think a good way to move forward might be to:
>>> * Create a project to own the RISC-V port, which is what this email is
>>> about.
>>>   I'm OK being the project lead, at least until we find someone who will
>>> have
>>> * Clean up our libffi port and submit it upstream.  Stefan O'Rear is in
>>> the
>>>   process of submitting the port now, so it should all be moving
>>> smoothly soon.
>>>   Submit patches for our Zero port.  While I didn't do the port I don't
>>> mind
>>>   cleaning it up and submitting it.  I've added Martin who was more
>>> involved
>>>   with the original port.  I think he's not working on RISC-V stuff now
>>> that
>>>   he's at Google, though.
>>> * Move forward with a proper OpenJDK port, starting with the template
>>>   interpreter and eventually adding C2.  I'm not sure if C1 is actually
>>>   deprecated, but we decided not to bother with it at Tilera because it
>>> didn't
>>>   seem worth the extra effort at the time.  Of course, this would be up
>>> to
>>>   whomever is actually doing the work :).
>>> There appears to be considerable community interest in a RISC-V OpenJDK
>>> port,
>>> so my hope is that while I don't have time to directly contribute much
>>> myself
>>> that we'll be able to get something sane up and running.  Interested
>>> users can
>>> test on QEMU, and we've recently announced a board (and associated beta
>>> program
>>> that provide free boards to open source developers) so there's some
>>> hardware to
>>> run on as well.
>>> I'd like to request that the Porters Group sponsors this project with me
>>> as the
>>> lead.
>>> Thanks!
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