Re: [PATCH 2/2] ppc64le live patch: get rid of mini stack frame
From: Petr Mladek
Date: Thu Mar 10 2016 - 07:51:35 EST
On Thu 2016-03-10 13:25:08, Petr Mladek wrote:
> On Wed 2016-03-09 18:30:17, Torsten Duwe wrote:
> > After the mini stack frame is no longer required for TOC storage, it can
> > be eliminated iff the functionality of klp_return_helper, which required
> > a stack frame for the extra return address previously, is carried out
> > by the replacement function now. This requires _every_ live patch replacement
> > function to execute the following (or similar) sequence of machine instructions
> > just before every return to the original caller:
> I have thought about it and it is a nono from my point of view.
> It is too error prone, especially that there are functions that
> call return on several locations.
BTW: How is this solved in kretprobes? Or is it easier there?