Re: Single MIPS kernel

[Ralf Baechle <ralf@linux-mips.org>]

On Wed, Oct 22, 2014 at 11:03:01AM -0700, David Daney wrote:

> There is another reason to have a relocatable kernel:  The security people
> are starting to demand it so that they can randomize the load address.

That may work for some platforms - but in the MIPS world we still have to
deal with very claustrophobic systems which barely leave any space to
move a kernel around.

> This is the approach I was thinking of taking.  There would be a small PIC
> wrapper that applied the relocations, and then passed control to the real
> entry point.
> 
> We would have to be careful of the ex_table, as that is now sorted at build
> time.  For that, we could go to the scheme used by x86, and have that
> addresses in the ex_table be relative, build time sorting is already working
> for x86 relocatable kernels.

That's probably more of an implementation detail.  I'm more concerned about
the overall bloat.  I think many embedded users are so addivted to benchmark
results that this going to make or break the whole scheme.

  Ralf