RE: [Linux-ia64] ia64 compressed makefile target

Luck, Tony
2002-10-23T20:43:51Z

>>>>> On Wed, 23 Oct 2002 10:46:32 -0700, "Luck, Tony" <tony.luck@intel.com>
said:

Tony> Or perhaps David will take the CONFIG_IA64_VMAP_KERNEL patch
Tony> that I posted a week ago which also allows the kernel to run
Tony> on systems without memory at the default link address.
Tony> Admittedly it's more than one line, but it contains much of
Tony> the same infrastructure that is needed to support kernel text
Tony> replication.

> I don't have a strong preference either way, but I do have some
> concerns about the VMAP_KERNEL. I really dislike the fact that it
> requires different versions of virtual-to-physical translations for
> kernel addresses. No other platform does that, so it will be a source
> of continual worry. Jesse, could you describe your approach a little
> more? I assume you link the kernel with "ld -r" and have an elilo
> that applies the relocations?

I'm not sure that the mapping the kernel is quite as scary as it
appears to be:
1) All of the places where we need to take special care are in
initialization code.
2) Code that can be loaded as a module (which is a whole lot of
code) cannot make any assumptions about __pa() working on
addresses in .text/.data/.bss

A relocating elilo sounds interesting too (it passes the "don't
do things in the kernel unless you really have to" test).

-Tony