Re: [Qemu-devel] Problem with PPC user emulation.

[Karel Gardas]

On Fri, 14 May 2004, Jocelyn Mayer wrote:

> On Fri, 2004-05-14 at 19:59, Karel Gardas wrote:
> > Hello,
> >
> > I've tried PPC user emulation provided by this week source tree, but w/o
> > success. I've tested crosstool's 4 test binaries (hello world in c/c++
> > static and dynamic) but all four crash with:
> >
> > thinkpad:/mnt/karel/cross-gcc/result/powerpc-405-linux-gnu/gcc-3.4.0-glibc-2.3.2/tmp$
> >  ppc.sh ./powerpc-405-linux-gnu-hello
> > *** ERROR: idx a0 already assigned to a direct opcode
> > *** ERROR: unable to join indirect table idx [a0-37]
> > *** ERROR initializing PPC instruction 0xa0 0x37 0xfe
> > /opt/qemu-scripts/bin/ppc.sh: line 3:  3496 Segmentation fault      
> > qemu-ppc -L 
> > /mnt/karel/cross-gcc/result/powerpc-405-linux-gnu/gcc-3.4.0-glibc-2.3.2/powerpc-405-linux-gnu/
> >  $@
> > thinkpad:/mnt/karel/cross-gcc/result/powerpc-405-linux-gnu/gcc-3.4.0-glibc-2.3.2/tmp$
> >
> > I used crosstool-0.28-pre13 for building ppc crosscompiler which is
> > gcc3.4.0 and glibc2.3.2 combination.
> >
>
> What is your host machine ?

Debian GNU/Linux 3.0.

> It seems there is a mess in the way sections are handled by this gcc
> version and/or for your host machine.
> This seems clear to me, because there can be no instruction with this
> opcode, as major opcode is 6 bits long in PPC and so can't be 0xa0.
>
> Could you please send me the qemu binary by mail, so I could check the
> executable structure (the opcode table structure, in fact...) ?

Sure! I will send you the smaller one (C statically linked hello world
app)

> But you may not be able to execute PPC405 dedicated binaries,
> as this CPU implements some instructions that aren't in the PPC spec
> then not emulated by Qemu.

Aha! This might be the issue.

> Those instructions seem not to be used in the
> program you tried, but you should check that you always compile with 
> -mcpu=powerpc flag
> (not -mcpu=405) to get only generic PPC code, in order to execute inside Qemu.

Hmm, I'm afraid whole gcc/glibc is compiled probably with -mcpu=405...

Anyway, thanks for the hint.

Karel
--
Karel Gardas                  address@hidden
ObjectSecurity Ltd.           http://www.objectsecurity.com