linux-kernel - Re: Suggestion: „spectre_v2=off“ and „nopti“ per default in "Intel Atom N270" case?

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Date:   Wed, 23 May 2018 19:07:07 +0200
From:   Johannes Hirte <johannes.hirte@...enkhaos.de>
To:     Pavel Machek <pavel@....cz>
Cc:     Christian Krüger <C.Krueger.B@....de>,
        linux-kernel@...r.kernel.org
Subject: Re: Suggestion: „spectre_v2=off“ and „nopti“ per default in
 "Intel Atom N270" case?

On 2018 Mai 23, Pavel Machek wrote:
> On Sat 2018-05-19 21:53:02, Christian Krüger wrote:
> > Hi,
> > 
> > Since the old "in-order-execution" Intel CPUs like the Intel Atom N270
> > (known for being installed in many Netbooks and Nettops) are not sensitive
> > for "Meltdown" & "Spectre" , wouldn't it be a good idea to exclude these
> > anyway "weak" CPUs from the costly patches by default?
> > 
> > Browsing the web, I can "feel the difference" if the matching kernel options
> > are applied on such a device.
> 
> Can you also measure the difference? Placebo effect is hard to avoid.
> 
> But yes, we do not need to do workarounds on non-buggy machines...
> 
> 								Pavel

On my Atom N270 there doesn't seem to be any workaround active with
kernel 4.14.42:

localhost ~ # cat /sys/devices/system/cpu/vulnerabilities/*
Not affected
Not affected
Not affected

Christian, did you verified the mitigations are active on your system?
What kernels are affected? 

-- 
Regards,
  Johannes