[RFC][PATCH] Move TASK_SIZE to 0xc0000000 for ppc32

[Scott Wood]

Kumar Gala wrote:
> Guys,
> 
> Here's a cut at a patch that cleans up the TASK_SIZE issue.  We now have
> TASK_SIZE @ 0xc0000000 for everything except PREP and use PAGE_OFFSET in
> SW TLB handlers.  I'm assuming 8xx will get a cleanup patch from
> PAGE_OFFSET testing (Dan :).

I'd rather this patch exclude 8xx along with PReP for now; the 8xx TLB 
handlers could be made to accept arbitrary task sizes, but not without 
slightly slowing them down (not that they're currently optimal -- IIUC, 
using the hardware tablewalk assist is expensive due to serialization on 
mtspr, and it doesn't really do anything that rlwimi can't do).  I'm not 
sure it's worth it -- does anyone really need more than 2GB userspace on 
an 8xx?

At the very least, we should have the 8xx patch in place before turning 
it on.

-Scott