[OpenBIOS] ppc64 MMU issues

[Segher Boessenkool]

>> I thought we might be missing some ELF sections in the linker script but
>> my tries based on `powerpc64-linux-gnu-ld --verbose` were unsuccessful.
>> Is there a way to turn on warnings for sections dropped, to rule this
>> out?

ld -M will show you everything you ever wanted to know, and much more.
readelf -Wa is useful for many problems as well.

>> Who's responsible for r2 setup - GCC-generated code or QEMU?
>
> r2 contains the GOT IIRC. But for ABI questions, it's probably best to
> consult Segher :). Unless I'm completely mistaken, usually the loader
> initializes r2, so in this case the asm code needs to set it up properly.

Depends what you call "loader".  Usually your crt1 equivalent sets GPR2.
It is probably a good idea to set it in all exception handlers as well
(if they want to call C code, or need it otherwise).


Segher