Re: 2.4.19pre3aa2

Dave Jones
2002-03-14T16:18:27Z

On Thu, Mar 14, 2002 at 10:53:01AM -0500, Bill Davidsen wrote:

> Since vendors (and consultants) like to build a single kernel for use on
> multiple machines, it would be nice if this could be done by some init
> code (released) and a module.

The relevant code is (where possible) marked as __init already.
So the init code gets thrown away whether needed or not.

> The code actually looks so small as to be unworthy of an option

It's not a matter of codesize, it's a correctness issue in the source.
#ifndef CONFIG_M686 is wrong. It assumes a P6 is the only CPU family
in existence without the bug, despite the fact there are probably close
to a dozen others.

> that many people would set it off not knowing was it was much less whether
> they needed it. This is not like a missing FPU where you can do a graceful
> reject of the instructions, if you have the bug and not the fix you are
> vulnerable to sudden total failures, correct?

No. You at worse vulnerable to a malicious user running hand-crafted code
(no compiler generates this code-sequence) bringing down the machine.

The proposal however was not to remove anything that we currently have.
Every kernel that is possible to be run on an affected box (i386/i486/i586)
would still have the workaround present. We just won't generate it in
Cyrix III, Athlon, Pentium 4, etc kernels..

--
| Dave Jones. http://www.codemonkey.org.uk
| SuSE Labs