APUS and IOs question

[Geert Uytterhoeven]

On Fri, 10 Nov 2006, Benjamin Herrenschmidt wrote:
> > My plan for moving APUS to arch/powerpc involves writing a new
> > bootloader (I'm currently hacking binutils to support AmigaOS binaries)
> > that builds a proper flattened device tree and calls the kernel, but I'm
> > not sure where the kernel virtual mapping that allows the kernel to run
> > from a fixed address should be set up -- if in the bootloader, the
> > kernel needs to be aware that changing the MMU settings will yield
> > interesting results, and if in the kernel, we need some platform
> > specific init code to handle that.
> 
> Well, the problem is that you basially have to hack the linear mapping,
> thus hitting anything that relies on __pa/__va or operating in real mode
> indeed.
> 
> How do you do for exception vectors ? Since those have to be either at 0
> or at ff* ? You stick branches at 0 to jump to where the kernel
> resides ?

IIRC (Roman please correct me if I'm wrong), APUS has them at ff* because the
memory at adress 0 is slower.

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds