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Date: Thu, 5 Nov 2009 15:30:29 +0300
From: Maxim Dounin <mdounin@mdounin.ru>
To: Kostik Belousov <kostikbel@gmail.com>
Message-ID: <20091105123028.GK1144@mdounin.ru>
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Cc: Attilio Rao <attilio@freebsd.org>, Dag-Erling Sm??rgrav <des@des.no>,
	Giovanni Trematerra <giovanni.trematerra@gmail.com>,
	FreeBSD Current <freebsd-current@freebsd.org>
Subject: Re: [PATCH] AMD Opteron Rev. E hack
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Hello!

On Thu, Nov 05, 2009 at 02:00:34PM +0200, Kostik Belousov wrote:

> On Thu, Nov 05, 2009 at 12:52:00PM +0100, Dag-Erling Sm??rgrav wrote:
> > Kostik Belousov <kostikbel@gmail.com> writes:
> > > I think there is no much sense in printing that hack in unused;
> > > instead, you should print info when option is enabled and vulnerable
> > > CPU is detected.
> > 
> > We should *definitely* print a warninhg when a vulnerable CPU is
> > detected and the option is *not* enabled.  How do you justify not
> > telling the user that you know the machine will crash as soon as he runs
> > 'make buildworld' with a high -j value?
> 
> We do not do this for other cpu bugs workarounds, why this should be
> different.

Well, probably is't a good idea to do so?  Something like NetBSD's 
sys/arch/x86/x86/errata.c seems to be right way to go.

> Besides, there were no confirmed reports of this happening
> in field (I mean the bug manifestation, not make -j panicing or hanging
> machine :).

http://bugs.mysql.com/bug.php?id=26081

Maxim Dounin