Messages in this thread | | | Date | Sun, 19 Apr 2020 11:55:19 -0500 | From | Josh Poimboeuf <> | Subject | Re: [RFC][PATCH 5/7] x86/speculation: Change __FILL_RETURN_BUFFER to work with objtool |
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On Sun, Apr 19, 2020 at 11:52:00AM -0500, Josh Poimboeuf wrote: > Are we still planning to warn about stack changes inside an alternative? > If so then this would still fail... > > In this case I think it should be safe, but I'm not sure how we can > ensure that will always be the case for other alternatives. > > And do the ORC entries actually work for this? As far as I can tell, > they would be associated with the .altinstructions section and not > .text, so it wouldn't work.
My preference would be to move RSB stuffing out-of-line too, like you did the retpolines. Or use static branches. Then we could add an objtool warning to prevent stack changes in alternatives.
-- Josh
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