Messages in this thread | | | Date | Fri, 19 Mar 2021 10:30:26 -0500 | From | Josh Poimboeuf <> | Subject | Re: [PATCH v2 14/14] objtool,x86: Rewrite retpoline thunk calls |
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On Fri, Mar 19, 2021 at 09:06:44AM +0100, Peter Zijlstra wrote: > > Also doesn't the alternative code already insert nops? > > Problem is that the {call,jmp} *%\reg thing is not fixed length. They're > 2 or 3 bytes depending on which register is picked.
Why do they need to be fixed length? Objtool can use sym->len as the alternative replacement length. Then alternatives can add nops as needed.
-- Josh
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