Re: Running m68k on qemu with external initramfs?

From: Rob Landley <rob@landley.net>
To: Laurent Vivier <laurent@vivier.eu>,
	John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Finn Thain <fthain@telegraphics.com.au>, linux-m68k@vger.kernel.org
Subject: Re: Running m68k on qemu with external initramfs?
Date: Sun, 12 Apr 2020 16:48:58 -0500	[thread overview]
Message-ID: <e0d7b1eb-c577-88ba-e318-a6b3b41f875c@landley.net> (raw)
In-Reply-To: <f1f62d19-bee9-537d-5641-8435567fb380@vivier.eu>

On 4/12/20 3:31 AM, Laurent Vivier wrote:
>>> QEMU is the one Laurent Vivier maintains that's been out of tree for something
>>> like 12 years now, the default branch claims to be "q800-dev" and the last
>>> commit was in december. It still runs my old aboriginal linux system image from
>>> 2014 (boots to a shell prompt).
>>
>> I think most of these things should be merged upstream these days but Laurent probably needs to correct me on what’s missing.
> 
> Yes, all is merged in QEMU master for Q800 emulation.
> 
> What stays in q800-dev are dev patches needed to run MacOS ROM but
> nothing works for the moment.

I confirmed that upstream qemu is Doing The Thing. Thanks and congratulations.
(It had been so long I stopped checking -git when my last vanilla build wasn't
doing it.)

What I've hit now is either a compiler bug or a subtle enough stack corruption
it doesn't manifest on any other platform and I haven't spotted it. I can fix it
by adding a NOP function call right before the segfault, but for the moment I'm
just punting worrying about it until after the next toybox release.

I checked in what I've got though. It builds a kernel and userspace for m68k,
and the _kernel_ seems to work.

Rob

P.S. I should poke Rich Felker again about fixing his kernel headers. He's
switched the default in musl-cross-make to use an out of tree kernel header
package from the sabotage project, which doesn't have s390x or m68k directories.
I'm just going "oh goddess, I fought this war 15 years ago with Mariusz Mazur's
headers package and I REALLY dowanna go back". He acknowledged the breakage last
month, but it seems to have fallen through the cracks. That's what the sed LINUX
is for in the toolchain build part of the reproduction sequence. The binutils
version change is because https://marc.info/?l=linux-sh&m=158544749818664&w=2
which ALSO still hasn't made it upstream, but hey, at least the kernel guys
added an SPDX license identifier to the .gitignore file, so they've got their
priorities.