Relocatable kernel for ppc44x

[David Laight]

> The PPC440X currently uses 256M TLB entries to pin the 
> lowmem. When we go for a relocatable kernel we have to :
> 
> 1) Restrict the kernel load address to be 256M aligned
> 
> OR
> 
> 2) Use 16M TLB(the next possible TLB page size supported) 
> entries till the first
> 256M and then use the 256M TLB entries for the rest of lowmem.

What is wrong with:

3) Use 256M TLB entries with the lowest one including
   addresses below the kernel base.

Clearly the kernel shouldn't be accessing the addresses
below its base address - but that is true of a lot of
address space mapped into the kernel.

	David