[uclibc-ng-devel] compile uclibc with retpoline switch

Waldemar Brodkorb wbx at uclibc-ng.org
Wed Apr 4 19:49:25 CEST 2018


Hi,
Ata, John  (US) wrote,

> Hi all,
> 
>  
> 
> With Spectre variant 2 (CVE-2017-5715), gcc has been updated to avoid branch
> prediction problems via the retpoline patch.  Specifically, by using either –
> mindirect-branch=thunk-inline or –mindirect-branch=thunk or –mindirect-branch-
> thunk-external, the compiler will convert indirect branches and function
> returns to call and return thunks thus avoiding speculative execution in those
> cases.  Of course, there is a performance penalty depending on the exact
> argument used.  Has anyone compiled uclibc with one of those switches?

I didn't tried it, yet. You might be the first :)

Any issues seen with that?

best regards
 Waldemar


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