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Date: Fri, 12 Jan 2018 11:07:06 -0700
To: Oliver Pinter <oliver.pinter@hardenedbsd.org>,
 "Zahrir, Abderrahmane" <Abderrahmane.Zahrir@ca.com>
From: Brett Glass <brett@lariat.org>
Subject: Re: Response to Meltdown and Spectre
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All:

The fix in this patch appears to be unconditional.

I do a lot of work with embedded Intel Atom processors, which do 
not implement speculative execution. (Only one of them even 
implements limited out-of-order execution.) These systems aren't 
terribly powerful by today's standards, and would suffer serious 
performance impacts should the fix be turned on unnecessarily. Will 
there be automatic detection of 32-bit Atoms (all of which are 
definitely not susceptible) and 64-bit Atoms (all of which, except 
for Avoton, are definitely not susceptible; Avoton might have some 
very limited exposure due to out-of-order execution, but may also 
not be vulnerable because the OOE is not speculative) to avoid 
unnecessary performance impacts?

--Brett Glass

At 05:14 AM 1/12/2018, Oliver Pinter wrote:

>The test patch is here: https://reviews.freebsd.org/D13797