Re: [OpenBIOS] [Qemu-ppc] FreeBSD powerpc issue

[Blue Swirl]

On Fri, Aug 24, 2012 at 9:45 PM, Andreas Tobler  wrote:
> Hello,
>
> I'm trying to get FreeBSD powerpc running with qemu.
> So far it loads the fbsd loader and the loader loads the kernel.
> The kernel starts booting but it hangs in an endless loop. It tries to print
> out a fatal_trap but it looks like the 'of' doesn't work properly (anymore?)
> at this stage.
>
> I have a remote debugger attached to the kernel and I can see where it
> hangs. But I can not figure out what caused the fatal trap here.
>
> An 'info registers' in qemu shows the srr0=fff025a4, this, as I understand,
> points to of_client_callback from OpenBIOS. (objdump -dS
> openbios-qemu.nostrip gives me this.)
>
> qemu is on 1.1.90, iow, a git snapshot from yesterday with OpenBIOS from
> 19th of aug.
>
> Is there a possibilty to 'debug' the OpenBIOS somehow?

CCing OpenBIOS list too.

We have a built-in debugger in OpenBIOS (maybe not well documented).
Then there's DEBUG_CIF in libopenbios/client.c and it should be
possible to add debugging print statements to forth/system/ciface.fs
too.
> I'm not sure whether it is a kernel issue or an OpenBIOS issue.

The problem could be that there's a MMU fault when the kernel calls
OpenBIOS, maybe because OpenBIOS is no longer mapped (MMU disabled?)
and then the above debugging would not help.
> Any hint is welcome.
>
> TIA,
> Andreas
>
> Here some info, it might help...
>
> telnet localhost 1200
> Trying ::1...
> Connected to localhost.
> Escape character is '^]'.
> > > Configuration device id QEMU version 1 machine id 2
> > > CPUs: 1
> > > Memory: 255M
> > > UUID: 00000000-0000-0000-0000-000000000000
> > > CPU type PowerPC,750
>
> Welcome to OpenBIOS v1.0 built on Aug 19 2012 13:11
> Trying cd:,\:tbxi...
> Consoles: Open Firmware console
>
> FreeBSD/powerpc Open Firmware loader, Revision 0.1
> ([e-mail], Sun Aug 19 10:32:07 CEST 2012)
> Memory: 261120KB
> Booted from: cd
>
> Loading /boot/defaults/loader.conf
> /boot/kernel/kernel text=0xb1ff27 data=0x5ff60+0x1ac7d0
> syms=[0x4+0x8c690+0x4+0xae1e0]
> /
> Hit [Enter] to boot immediately, or any other key for command prompt.
> Booting [/boot/kernel/kernel]...
> Kernel entry at 0x100100 ...
> KDB: debugger backends: ddb
> KDB: current backend: ddb
>
> QEMU 1.1.90 monitor - type 'help' for more information
> (qemu) info registers
> NIP 009463ec   LR 009463b0 CTR 0094638c XER 00000000
> MSR 00001032 HID0 00000000  HF 00000000 idx 1
> TB 00000000 1000640182 DECR 3294327117
> GPR00 0000000000000001 0000000000c7ba00 0000000080020400 000000000fd00000
> GPR04 00000000005b5128 000000000094638c 00000000005b5128 0000000000c7bab0
> GPR08 000000000fd00000 0000000000c7bab0 0000000000000000 0000000000c7ba00
> GPR12 000000000de9bba0 0000000000000000 00000000fff30714 00000000fff30ec8
> GPR16 00000000fff2f256 0000000004000000 00000000fffb36cc 00000000fffb3ecc
> GPR20 0000000000f68000 0000000000000004 00000000fff2f03f 00000000fff2efbf
> GPR24 00000000fff2f047 00000000fffb3630 0000000001c2f3b0 0000000001c325a8
> GPR28 0000000080020002 0000000000805180 00000000f97ff97f 0000000000c7ba00
> CR 40003034  [ G  -  -  -  EO -  EO G  ]             RES ffffffff
> FPR00 0000000000000000 0000000000000000 0000000000000000 0000000000000000
> FPR04 0000000000000000 0000000000000000 0000000000000000 0000000000000000
> FPR08 0000000000000000 0000000000000000 0000000000000000 0000000000000000
> FPR12 0000000000000000 0000000000000000 0000000000000000 0000000000000000
> FPR16 0000000000000000 0000000000000000 0000000000000000 0000000000000000
> FPR20 0000000000000000 0000000000000000 0000000000000000 0000000000000000
> FPR24 0000000000000000 0000000000000000 0000000000000000 0000000000000000
> FPR28 0000000000000000 0000000000000000 0000000000000000 0000000000000000
> FPSCR 00000000
>  SRR0 fff025a4  SRR1 40003030    PVR 00080301 VRSAVE 00000000
> SPRG0 0fd00000 SPRG1 00c7c090  SPRG2 0094e3f0  SPRG3 00000400
> SPRG4 00000000 SPRG5 00000000  SPRG6 00000000  SPRG7 00000000
>  SDR1 0100001f