On 26.11.2021 22:22, Andrew Cooper wrote: > @@ -279,6 +280,27 @@ static void init_or_livepatch _apply_alternatives(struct > alt_instr *start, > > if ( dest ) > { > + /* > + * When building for CET-IBT, all function pointer > targets > + * should have an endbr64 instruction. > + * > + * If this is not the case, leave a warning because > + * something is wrong with the build. > + * > + * Otherwise, skip the endbr64 instruction. This is a > + * marginal perf improvement which saves on instruction > + * decode bandwidth. > + */ > + if ( IS_ENABLED(CONFIG_HAS_CC_CET_IBT) ) > + { > + if ( is_endbr64(dest) )
I would have given my R-b, but I don't see where is_endbr64() is coming from, and you don't list any prereqs here or in the cover letter. I'm afraid I don't fancy going hunt for it in the many other pending patches. Hence only on the assumption that the helper has got introduced before: Reviewed-by: Jan Beulich <jbeul...@suse.com> Jan