[OpenBIOS] ppc64 boot issues

[Blue Swirl]

On Tue, Dec 7, 2010 at 9:06 PM, Andreas Färber <andreas.faerber at web.de> wrote:
> Hello,
>
> With or without the pending ofmem patches, ppc64 boot currently hangs after
> "Trying cd:,\\:tbxi..." (before "Trying cd:,\ppc\chrp\bootfile.exe...").
> Symptom is, 0x700 program exception vector (not 0xfff00700) is being called
> with SRR1 pointing to some address that's neither in the low vectors range
> nor in OpenBIOS itself apparently.
> I noticed that branching relatively to unexpected_excep from there is wrong
> and patched it to bctr there (which unfortunately appears to break 32-bit
> ppc64), but usually it does not manage to properly do the printk()
>
> Here's what I found out so far:
>
> * a breakpoint for bootinfo_loader_init() or so is not reached
> * The "Trying" comes from (encode-bootpath) in forth/debugging/client.fs
> * `debug (encode-bootpath) boot` does not return from open-dev
> * `debug open-dev` does not return from path-resolution
> * path-resolution gets called "endlessly" (5+ times single-stepping it), the
> hang occurred after successfully returning from some instance (after having
> successfully done so for a previous instance)
>
> Does anyone have a hunch what might be going wrong? Or tips how to further
> debug?

Does running QEMU with flag -d in_asm,int reveal anything? How about
recompiling with DEBUG_SOFTWARE_TLB in target-ppc/op_helper.c enabled?