Re: [PATCH] Fix J-core aic warning spam

Hi Rob!

On Sat, 2023-04-29 at 22:45 -0500, Rob Landley wrote:
> On 4/29/23 15:07, John Paul Adrian Glaubitz wrote:
> > Hi Rob!
> > 
> > On Wed, 2023-04-19 at 20:24 -0500, Rob Landley wrote:
> > > J-core binary toolchain tarball:
> > > 
> > > https://landley.net/toybox/downloads/binaries/toolchains/latest/sh2eb-linux-muslfdpic-cross.tar.xz
> > 
> > OK, I can actually build a J2 kernel with that. Are there instructions somewhere which explain
> > how to boot such a kernel on a Turtle board? Then I can give it a try on my personal one.
> 
> Just copy the vmlinux file to "vmlinux" on the sd card. (It needs an initramfs,
> or in theory a built-in kernel command line from kconfig doing the root= thing,
> but either way you should get serial output on the usb with something like "sudo
> busybox microcom -s 115200 /dev/ttyACM0".)

Thanks. I found my J2 board in the meantime.

> I built 6.3 with toybox's mkroot.sh and booted it on the board, although that
> was with a 10 patch stack in my tree. Only four of which are j-core related: one
> is the boot warning spam, of them adds the ugly ethernet driver, one makes uio
> work on nommu, and one adds support for a variable clock base because we plugged
> in some peripheral hardware that wasn't clocked in base 10 back in
> https://landley.net/notes-2020.html#04-11-2020 and... here, lemme just fling it
> all up github:
> 
>   https://github.com/landley/linux/commits/turtle-v6.3

We should get as many of these patches upstreamed as possible.

I will also continue reviewing old patches from the mailing list, I already
assembled a list of older patches many of which have not been applied.

If possible, the original author of the various J2 patches should post them
for review.

> That's my current stack forwarded ported on top of 6.3. You probably don't need
> most of that, but I booted it on the board a few days ago. (Yes, the ethernet
> driver is terrible.)
> 
> > And do you have a root filesystem available for J2 that I can use?
> 
> I mostly use a toybox mkroot build. The easy way to build it yourself is:
> 
>   git clone https://github.com/landley/toybox
>   cd toybox
>   mkroot/mkroot.sh CROSS_COMPILE=/path/to/sh2eb-linux-muslfdpic-
>   ls -l root/sh2eb

Thanks. That should be enough.

> > Do you know who authored these patches?
> 
> I think some came from Sato-san and the rest from Rich, but I'm not 100% sure?
> Rich has been the one maintaining them, and Jeff before that.
> 
> https://github.com/richfelker/musl-cross-make/commits/master/patches/gcc-5.3.0/0004-j2.diff
> implies that the patch came from Patrick Oppenlander, who sounds familiar?
> https://github.com/pattop

Doesn't ring a bell at the moment.

> > We should get these merged upstream which should be
> > easier these days since the FSF has lowered the barriers regarding the copyright assignment.
> 
> I'm all for it. Jeff had some more pending todo fixes for the toolchain that he
> might want to sweep up into such a push.

Jeff, your turn, please ;-).

> Me, I want to switch over to llvm but Jeff thinks its optimizer is still
> terrible for embedded systems. But then I've heard it had some pretty bad
> regressions 12.0 to, so...

While SuperH/J2 is not an official LLVM target, there is actually an LLVM toolchain
for J2, see:

> https://github.com/francisvm/j2-llvm

> I'm still using 9.4 because when I tried to build 11.2 back in February it went:
> 
> sh2eb-linux-muslfdpic/src_gcc/libstdc++-v3/../libgcc/unwind-pe.h:270:25: error:
> '_Unwind_gnu_Find_got' was not declared in this scope
>   270 |               result += _Unwind_gnu_Find_got ((_Unwind_Ptr) u);
> 
> And I haven't circled around to try to dig up why yet. (I want to bisect the gcc
> repo to see what commit broke it, but that involves getting the horrific
> autoconf dependency stack working which went REALLY WEIRD since the last time I
> looked at it, possibly version skew with debian oldstable package versions. The
> tarball versions ship cooked ./configure scripts that don't need the full
> gnu/aaaaaaaaah environment install with automake and everything...)

GCC for SH itself works fine for me, so I assume an issue with your build environment.

Adrian

-- 
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