Re: [RFC PATCH 1/1] arm64: implement live patching

[Joe Lawrence]

On Mon, Jun 07, 2021 at 11:20:58AM +0100, Mark Rutland wrote:
> On Fri, Jun 04, 2021 at 04:59:30PM -0700, Suraj Jitindar Singh wrote:
> > It's my understanding that the two pieces of work required to enable live
> > patching on arm are in flight upstream;
> > - Reliable stack traces as implemented by Madhavan T. Venkataraman [1]
> > - Objtool as implemented by Julien Thierry [2]
> 
> We also need to rework the arm64 patching code to not rely on any code
> which may itself be patched. Currently there's a reasonable amount of
> patching code that can either be patched directly, or can be
> instrumented by code that can be patched.
> 
> I have some WIP patches for that at:
> 
>   https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=arm64/patching/rework
> 
> ... but there's still a lot to do, and it's not clear to me if there's
> other stuff we need to rework to make patch-safe.
> 
> Do we have any infrastructure for testing LIVEPATCH?
> 

Hi Mark,

If you're looking for a high level sanity check, there are livepatching
integration selftests in tools/testing/selftests/livepatch.  Let me know
if you have any questions about those.

Regards,

-- Joe