[PATCH] Set cpu explicitly in kernel compiles

[Paul Mackerras]

Tom Rini writes:

> Why won't it work with generic gcc4 ?  Will something more than a lot of
> extra nops be added?

Well, say you are compiling for 405.  You either need to have a gcc
that was configured with --with-cpu=405, or you need to have hacked
arch/ppc/Makefile to add -mcpu=405.  In both cases the problem doesn't
arise.  It only arises if you have a biarch gcc4 that was configured
without any --with-cpu=xxx option and is run without any -mcpu=xxx
option.

If you think we should have -mcpu=xxx on the command line for 4xx,
44x, 8xx, etc., then that's fine, but that is a separate problem from
what my patch was addressing (one which my patch might make it easier
to fix, though).

Paul.