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    SubjectRe: [PATCH/RFC] ppc64 livepatch: frameless klp_return_helper using odd TOC
    On Thu, Mar 24, 2016 at 01:23:01PM +1100, Balbir Singh wrote:
    > On 24/03/16 02:58, Torsten Duwe wrote:
    > >
    > > 1. Heuristics are bad. The better they are, the more subtly the
    > > way they might fail.
    [...]
    > I missed this yesterday, not on cc, but caught it on the list today

    I replied to Michael's last post and removed the back reference to start
    a new thread. The list is rather long... sorry I didn't notice.

    > Thanks for working on this. I did a quick look, so the CR+4 code

    Yes. It's only a proof of concept. That idea is yours, no doubt, and
    should be mentioned in the final submission. I already wrote it in my
    previous version, where I also have changed the arithmetic to produce
    small positive deltas.

    > plus heuristics for global/local call detection?

    Nope, definitely not! I flag global entries unambiguously.
    I had a version with R12/LR heuristics on Monday which I dumped.

    > I'll review this soon - hopefully tonight, but we have a long weekend coming up, so there might be delays. In the meanwhile feel free to add my signed-off-by for the CR+4 code. I am also looking at a different approach -- per thread lr0 stack.

    This CR+4 code leaves only 1 slot, so sibling calls are extremely dangerous,
    as I mentioned. But with a little attention, this patch works very well.

    I mostly wanted to hear opinions about a transient odd TOC value
    before I start polishing.

    Torsten

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