Messages in this thread | | | Date | Sun, 19 Apr 2020 20:58:38 +0200 | From | Peter Zijlstra <> | 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 11:55:19AM -0500, Josh Poimboeuf wrote: > 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.
I effectively did the static_branch thing, but with an alternative, it's in the last patch, due to me being a moron and not refreshing the stack before sending it out.
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