HIGHMEM now working

Hi Paul, $LIST

I managed to get CONFIG_HIGHMEM to work on CHRP. What I
basically did is to move the HIGHMEM area down from 0xfe to
0xf6. See my patch against the 2.4.0-test9 kernel.org kernel
below. I tested this patch on a 44P-270 with 3GB, a 44P-170
with 1GB and a 43P-150 with 512MB.

On the 150 I faked HIGHEM with MAX_LOW_MEM == 256MB because
I don't have a box with more RAM in it. It worked fine.

I saw that you recently did some fixes for HIGHMEM on CHRP, but
they did not work. Actually, I can't get the kernel to boot on a
270. It dies in 'c01d9ff0 D init_task_union',
but anyway it won't even without HIGHMEM enabled, it didn't pass
'python_pcibios_read_config_byte'.

Why not just lower PKMAP_BASE to 0xf6000000, will this break
someone?

Tilmann