Re: [Qemu-devel] Openbios upgrade broke sparc32 linux.

[Olivier Danet]

On 28/06/2013 23:44, Mark Cave-Ayland wrote:
> On 28/06/13 03:08, Rob Landley wrote:
>
> > Commit 467b34689d27 upgraded the openbios image, and ever since my linux
> > system images hang about the time they try to initialize interrupts.
> >
> > http://landley.net/aboriginal/bin/system-image-sparc.tar.bz2
> >
> > Extract that and "./run-emulator.sh" in the tarball. Using qemu 1.2.0
> > for example works fine, you get a shell prompt. Using 1.5.0 hangs.
> >
> > Rob
>
> Hi Rob,
>
> Thanks for the bug report. I did a quick bisect on OpenBIOS and it 
> points to the following commit:
>
> commit 167aafd70f64e74a77787ca5bf9f4dc750b27fc3
> Author: blueswirl <address@hidden>
> Date:   Sun Feb 3 16:50:11 2013 +0000
>
>     SPARC32: microSPARC-II identification
>
>     For the microSPARC-II = Fujitsu MB86904 = Sun STP1012PGA,
>     PSR.IMPL=0 and PSR.VERS=4.
>
>     This CPU model is used as default by QEMU when emulating
>     a SparcStation-4 or SparcStation-5.
>
>     Signed-off-by: Olivier DANET <address@hidden>
>     Signed-off-by: Blue Swirl <address@hidden>
>
>
> The commit itself is very simple and looks like this: 
> http://git.qemu.org/?p=openbios.git;a=commitdiff;h=0fe772df8717ef75d91eae8ef221e9966ce2fd7f.
>
> My guess would be that Linux is trying to do some slightly different 
> initialisation based upon identifying the CPU, but I'm not too 
> familiar with the kernel code myself. Blue/Olivier - can either of you 
> comment on this?
>
>
> ATB,
>
> Mark.

How embarrassing...

- QEMU 1.5.1 can boot Debian Etch (kernel 2.6.18), RedHat 4.2 (kernel 
2.0.30), NetBSD 6.1 and OpenBSD 5.3.

- Your image (Linux 3.8) can be started with a TurboSparc CPU : qemu 
-cpu "Fujitsu MB86907".

- My SparcStation-5 has a 110MHz MicroSPARC-II and the .attributes (aka 
.properties) fields are identical
to OpenBIOS values, except for the mask_rev : I have 0x26, OpenBIOS sets 
0x23

Before the patch, OpenBIOS had an incoherence between the PSR register 
content and the BIOS defined values.
In Linux "arch/sparc/mm/srmmu.c:get_srmmu_type(void)", this correspond 
to "a TurboSparc emulating Swift".
(Swift is the MS-2).

TurboSPARC could be the new QEMU default, but, ideally, the MS-II should 
be preferred
 as it is compatible with more OSes ( hoping to run NextStep in QEMU 
one day ...).

Maybe recent Linux kernels are not compatible with the way QEMU emulates 
the MS-II...

Regards
Olivier
[temlib.org]