Re: Requirements for retpoline in Linux 4.15 (was: Re: Linux 4.15)

From: Martin Steigerwald
Date: Mon Jan 29 2018 - 06:19:50 EST


Martin Steigerwald - 29.01.18, 11:42:
> > Try removing .cache.mk which has 'remembered' that your GCC doesn't
> > support retpoline.
>
> I bet there have been "*.cache.mk" files around from previous pre gcc-7.3
> compiles.
>
> Trying again after
>
> % find -name ".cache.mk" -delete
>
> on kernel source tree.
>
> Will report back.

The whole thing works:

% grep . /sys/devices/system/cpu/vulnerabilities/*
/sys/devices/system/cpu/vulnerabilities/meltdown:Mitigation: PTI
/sys/devices/system/cpu/vulnerabilities/spectre_v1:Vulnerable
/sys/devices/system/cpu/vulnerabilities/spectre_v2:Mitigation: Full generic
retpoline

I bet the virtualbox modules compiled by virtualbox-dkms will taint the
support, but I bet sooner or later they will support retpoline as well.
(Another reason to switch to KVM one day.)

Thank you.
--
Martin