Segmentation fault in __uClibc_main on m68k

[Rob Landley]

On Sat, May 30, 2015 at 3:06 AM, Waldemar Brodkorb <wbx at openadk.org> wrote:
> Hi,
> Rob Landley wrote,
>
>> Of course somebody did a uclibc-ng fork (bought the domain name and
>> everything), but I talked to him and his reason for doing it is there
>> are some obscure targets even glibc doesn't support, and I expect that
>> as musl grows support for those targets his reasons for doing it will
>> gradually fade away. *shrug* We'll see.
>
> We'll see. In the FPGA world there are four main architectures,
> NIOS2, ARC, Microblaze and Xtensa. Nios2 and Microblaze are
> supported by GNU libc. ARC and Xtensa are only supported by
> uClibc/uClibc-ng. There are nice developers and company's behind.
>
> For all the no-MMU architectures or systems there is only one option
> at the moment. uClibc/uClibc-ng!

Actually I spent this morning walking Rich through setup of his new
sh2 nommu board this morning.

The company I'm working for (se-instruments.com) is producing a new
sh2-compatible processor (the patents expired, clean room clone by
engineers in canada), and I mailed Rich a little FPGA board with the
bitstream that runs that, along with toolchain info and a kernel patch
and so on so he can boot stuff and start adding musl support.

Due to this, we've been talking about nommu support for musl for... 4
months? We talked about it at lunch at ELC in california month before
last. (I also spoke to the buildroot maintainer and the openembedded
maintainer, but I've been too swamped to follow up with them yet...)

> I am maintaining an developing buildsystems for embedded devices
> since more than 10 years, I don't think I will give up on uClibc-ng
> so fast.

Ok. Good luck. I'll be over here.

Microblaze I have a todo item to set up a qemu based environment for
and port aboriginal linux to, and generally once I do that Rich adds
target support because it's then easy for him. I see a
qemu-system-xtensa so might give that a try too. I don't see arc or
nios in qemu, so probably won't bother worrying about either any time
soon.

>> Remember when buildroot announced they would switch their default libc
>> if the uClibc developers couldn't get a new release out? Remember how
>> that was over a year ago, ala
>> http://lists.busybox.net/pipermail/uclibc/2014-February/048252.html ?
>> Well instead what happened was
>> http://lists.busybox.net/pipermail/buildroot/2013-October/079661.html
>> became http://git.buildroot.net/buildroot/commit/?id=c29799330464fb5d152f1b3d550fcbda69c58a3d
>> which became https://www.phoronix.com/scan.php?page=news_item&px=Musl-Libc-GCC-Support
>> and at this point it's pretty much over except the cleanup. They
>> didn't _announce_ a migration, they just did it. At this point if
>> uClibc had a new release I expect they'd smile and nod and _continue_
>> not to care because there are better alternatives now, once that
>> haven't established a pattern of chronic multi-year development
>> constipation.
>
> That is not correct. They did not silently migrate to musl.
> Musl is a choice like Gnu Libc in their buildsystem.

They have not changed their default yet, true.

> They will migrate in the next release cycle, but they migrate to
> uClibc-ng as default C library for their system.

Ok.

> This will get a better code coverage, than my own embedded-test
> project, which at the moment only running the uClibc-ng testsuite
> regulary.
>
> But may be Rob comes up with nommu.org contents with a musl
> libc for at least sh2 nommu, soon.

Working on it as we speak, but also trying to clean up the sh2 kernel
patch tos end upstream for 4.2 (probably not gonna make it), and get
ready for our talk about this at linuxcon japan (panel slot approved
at the last minute from the standby list, thursday the 4th at 11:30,
woo! Gotta do slides!)

We already did a dry run of this at the Linux Jamboree last month
(http://elinux.org/Japan_Technical_Jamboree_52#Agenda 4pm slot, that
has a link to youtube video of our talk) but I was hugely jetlagged
and Kawasaki-san (the original SuperH architect, working with us on
this as a consultant) did his part of the talk in japanese because of
our audience. The most coherent third was Jeff Dionne (the founder of
uclinux.org who handed it off when he moved to Japan in 2003), who is
the CEO of the company doing all this.

So you know... working on it. :)

(I also submitted the same talk proposal to Plumber's, but it's still
pending. Did I mention we're releasing the VHDL for this open source
so you can build and modify your own processors as you like? The sh4
patents expire in 2016 and then we can add an mmu, but there are
advantages to nommu systems so we aren't dropping that side then
either...)

> <advertisement on>
> Best choice for exotic architectures and hardware is OpenADK + uCLibc-ng ;)
> <advertisement off>

We all do our own stuff. :)

> best regards and happy hacking,
>  Waldemar

Rob