Hi,

> Okay.  What happens when the kernel tries to access some of that beyond
> 256M memory via the BAT-mapped 1:1 window?

Hmm, ok, I did take a look at the macppc port.  Turns out that the
battable isn't initialized as expected.  It probably works for machines
up to 512M real memory.

What happens is that the battable is initialized to map several 256M
ranges 1:1 from virtual to physical addresses:

The following ranges are always setup to be mapped:

	0x00000000-0x0fffffff	initial 256M
	0x80000000-0x8fffffff	PCI space
	0x90000000-0x9fffffff	PCI space
	0xf0000000-0xffffffff	obio space

In addition to that, the top 256M range of physical memory seems to be
setup to be mapped.  So you are probably lucky for machines up to 512M.

This is not how things were intended.  The intention was to have
everything mapped 1:1 via the BAT registers, except for the mentioned
512M range of 0xd0000000-0xefffffff.  Should be quite easy to fix.

Ciao,
Wolfgang
-- 
ws@TooLs.DE     (Wolfgang Solfrank, TooLs GmbH) 	+49-228-985800