5 Apr
2018
5 Apr
'18
11:56 p.m.
Thanks! I built both 32 bit and 64 bit uclibc with –mindirect-branch=thunk placed in the
UCLIBC_EXTRA_CFLAGS field so far I haven't noticed any problems. As this gets more
use/exposure, I'll update...
Take care,
----
John Ata, CISSP
Senior Principal Software Engineer
Electronics Systems
STOP Operating System Software Development
T 703-563-8115 | F 703-668-4359 | john.ata(a)baesystems.com
http://www.baesystems.com/csp
-----Original Message-----
From: devel [mailto:devel-bounces@uclibc-ng.org] On Behalf Of kapeka
Sent: Wednesday, April 04, 2018 2:56 PM
To: devel(a)uclibc-ng.org
Subject: Re: [uclibc-ng-devel] compile uclibc with retpoline switch
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EXTERNAL EMAIL -- This message originates from outside our organization.
HI;
On Mi, 2018-04-04 at 19:49 +0200, Waldemar Brodkorb wrote:
Hi,
Ata, John (US) wrote,
I did with standard compiler settings (gcc 7.3.0 and gcc 5.5 with
patches) and got
Mitigation: Full AMD retpoline
on a PC Engines APU2 compared without gcc 5 patch:
Vulnerable: Minimal AMD ASM retpoline
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?
Running it for a few weeks.
Observed some hickups after a few running the uclibc-ng machine with
gcc5-based toolchain for WIFI, but not shure if it's related to the
Spectre2 mitgation.
regards kp
best regards
Waldemar
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