[OpenBIOS] PReP PowerPC "emulation"

[Mark Cave-Ayland]

Andreas Färber wrote:

> qemu-system-ppc64 w/ either stock QEMU OpenBIOS or r862 with OSX host 
> and ppc MMU patches:
> 
> C>> annot manage 'OHCI USB controller' PCI device type 'usb':
>  >>  106b 3f (c 3 10)
> 
>  >> =============================================================
>  >> OpenBIOS 1.0 [Aug 17 2010 14:41]
>  >> Configuration device id QEMU version 1 machine id 3
>  >> CPUs: 1
>  >> Memory: 128M
>  >> UUID: 00000000-0000-0000-0000-000000000000
>  >> CPU type PowerPC,970FX
> Welcome to OpenBIOS v1.0 built on Aug 17 2010 14:41
> 
> 0 > load cd:,\ppc\chrp\bootfile.exe  ok
> 0 > go No valid state has been set by load or init-program
>  ok
> 0 > boot cd:,\ppc\chrp\bootfile.exe No valid state has been set by load 
> or init-program
>  ok
> 0 > dir cd:,\ppc\chrp
>       2048 2007-07-03 17:39:44 .\
>       2048 2007-07-03 17:32:05 ..\
>   12487680 2007-07-03 17:39:24 bootfile.exe
>  ok
> 0 >
> 
> 
>> Also, what format is the AIX bootloader - is it an ELF executable?
> 
> $ file /Volumes/CDROM/ppc/chrp/bootfile.exe
> /Volumes/CDROM/ppc/chrp/bootfile.exe: ELF 32-bit MSB executable, PowerPC 
> or cisco 4500, version 1 (SYSV), statically linked, corrupted section 
> header size
> 
> Andreas

Right. So in the case that you see the message "No valid state has been 
set by load or init-program", this means that either the load failed or 
init-program failed to detect a valid ELF header for the current 
architecture.

First thing to check is that the executable is being loaded from disk, e.g.

load cd:,\ppc\chrp\bootfile.exe

then dump the first 200 bytes of memory to make sure an ELF header is 
present (i.e. the load from disk was successful):

load-base 200 dump

If the ELF header is present then it must be init-program which is 
failing. If the ELF header is not present, you'll need to take a look in 
either libopenbios/load.c and/or libopenbios/elf_load.c at elf_load() 
and elf_init_program().

The one thing that I did notice is that you are attempting to launch a 
PPC32 ELF file under a PPC64 Qemu, so perhaps it is the checks in 
is_elf() which are failing? Try taking a look at the relevant constants 
in include/arch/ppc/elf.h.


HTH,

Mark.

-- 
Mark Cave-Ayland - Senior Technical Architect
PostgreSQL - PostGIS
Sirius Corporation plc - control through freedom
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