LDREX/STREX and pre-emption on SMP hardware

Catalin Marinas catalin.marinas at arm.com
Mon Sep 14 08:57:32 EDT 2009

On Mon, 2009-09-14 at 07:43 -0500, Bill Gatliff wrote:
> Catalin Marinas wrote:
> > And here's an untested patch to clear the exclusive monitor on the
> > exception return path. If you are OK with the idea, I'll do some testing
> > before pushing it for upstream:
> How are you going to "test" for this one? It's such a corner case, it's 
> going to be tricky to validate that your changes are actually getting 
> test coverage methinks...

I'm just testing it to make sure it doesn't break the compilation :-). I
can do a few more tests like running LTP in parallel but it may not find
any problems. It's strange that we haven't hit a bug yet (and we run
some intensive testing for CPU validation in ARM) or maybe we blamed
something else.

Apart from the switch_to and atomic_set modifications, the patch cannot
do more harm. As for these functions, I don't see any reason why the
modifications would not be correct but we can delay the merging until we
are sure (anyway, the more people looking at the patch, the better).


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