[lowrisc-dev] Re: [musl] Interest in "Porting musl libc to RISC-V" project for GSoC 2016

Rich Felker dalias at libc.org
Fri Mar 4 03:02:26 GMT 2016


On Fri, Mar 04, 2016 at 09:54:44AM +0900, Masanori Ogino wrote:
> Hello,
> 
> 2016-03-04 7:06 GMT+09:00 Szabolcs Nagy <nsz at port70.net>:
> > last time iirc musl port was considered to be
> > not large enough in itself for a gsoc project
> > (i think it should not take more than 2 months
> > but i don't know the current state of risc-v
> > qemu/linux/gcc/etc)
> >
> > you might need to think additional things to work on.
> >
> > for musl, one idea is to invest extra time on testing.
> >
> > for risc-v i think polishing the toolchain and the docs
> > would be useful.
> 
> Agreed.
> 
> > there are some basic problems with the risc-v software
> > eco-system:
> >
> > there is no proper sysv psabi spec. (designing one would
> > have been better than copying obsolete nonsense from mips
> > as i can see in the glibc port.)
> 
> Hmm, ABI is an important factor for the proposal, but I probably won't
> have enough time to invent a new ABI and implement it during this
> summer...
> Anyway, would you give me any well-designed psABI (or non-SysV-psABI) examples?

I don't think you'd need to change/redesign the ABI (since it's
already being used on FreeBSD, presumably whatever current Linux
kernel port exists, and maybe other targets, and didn't look bad when
I looked at it), but a nice clean psABI document would be nice to
have.

> > nothing is upstream yet (gcc/linux/.. ports are
> > maintained out of tree, working with the upstream
> > community is important for many reasons).
> 
> Agreed with the importance of merging to upstream.
> 
> > risc-v mailing lists are not public, only subscribers
> > can see or participate in the discussions. (this is
> > bad given that there are no specs, no upstreamed code
> > so no source of information for outsiders.)
> 
> I think it would be great if archives are public. I don't know the
> reason why the project decide to do so.

Yes, that would be really nice.

> > for a musl port this means that we don't have abi
> > stability guarantees, the port can stop working with
> > the rest of the risc-v software stack.   so for a
> > successful port i think some scripts should be developed
> > to build and test the latest risc-v things against musl
> > (cross-toolchain, rootfs, etc) so we can keep it working.
> 
> Indeed it's great to have an automated testing infrastructure. I really love CI.
> 
> Thank you for your suggestion!

I have a few other ideas I'm going to post to the list for elements
that could be incorporated into proposals. I'll follow up as a
separate email.

Rich



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