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

Ata, John (US) john.ata at baesystems.com
Mon Apr 2 22:19:31 CEST 2018


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?

Take care,
----
John Ata, CISSP
Senior Principal Software Engineer
Electronics Systems
STOP Operating System<http://www.baesystems.com/en-us/product/stop> Software Development

T 703-563-8115 | F 703-668-4359 | john.ata at baesystems.com<mailto:john.ata at baesystems.com>
http://www.baesystems.com/csp

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