Subject: Re: Changing kernel base address (was: Re: Heads up: shared arm
To: Mike Pumford <mpumford@black-star.demon.co.uk>
From: Reinoud Zandijk <imago@kabel065011.kabel.utwente.nl>
List: port-arm32
Date: 01/19/2001 02:50:39
Hi Mike, Robert,

On Fri, 19 Jan 2001, Mike Pumford wrote:
> > >Right I have now done some tinkering and it turns out that moving VIDC/IOMD 
> > >and the podules is not that straightforward as tweaking a few #defines and 
> > >recompiling. The code in initarm assumes that these have been mapped by the 
> > >bootloader at f6000000. I have a partial work round for this but the kernels 
> > >crash after switching to the final page tables. On a more positive note it is 
> > >possible to move the VRAM (or video DRAM) without too much effort.

I'll have a look at it .... as far as i know i can move stuff around the
way i like on my bootloader... so i'd be most interested to see if it
really would crash if i change this !! Hmm... maybe some other constants
need tweeking ... will see !

> [IOMD code snipped]
> > Why not delete it and add any extra checks needed to iomdattach().

In a way it looks sensible, but there are more changes than just the iomd
as far as i know ....

> It's not actually a problem while running initarm (you just have to do the 
> mapping yourself in initarm) Unofortunately relocating IOMD and VIDC seems to 
> cause a kernel trap some time after switching to the full kernel page tables. 
> However it does make sense to do this check elsewhere.

Memory mapping is quite unforgiving yes.... it just crashes... with no
warnings ...

Cheers,
Reinoud