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Date:      Wed, 3 Oct 2012 16:34:27 +0100
From:      RW <rwmaillists@googlemail.com>
To:        Dag-Erling =?ISO-8859-1?Q?Sm=F8rgrav?= <des@des.no>
Cc:        freebsd-security@freebsd.org
Subject:   Re: Collecting entropy from device_attach() times.
Message-ID:  <20121003163427.2acff4e6@gumby.homeunix.com>
In-Reply-To: <86626raojm.fsf@ds4.des.no>
References:  <20120918211422.GA1400@garage.freebsd.pl> <20120919231051.4bc5335b@gumby.homeunix.com> <20120920102104.GA1397@garage.freebsd.pl> <201209200758.51924.jhb@freebsd.org> <20120922080323.GA1454@garage.freebsd.pl> <20120922195325.GH1454@garage.freebsd.pl> <505E59DC.7090505@gmail.com> <20120923151706.GN1454@garage.freebsd.pl> <5060D723.6020305@gmail.com> <CAG5KPzxf0Rfufk5K6Jt4e85xc7zXY_B3a2Sq0Uf_uVLHbV-baw@mail.gmail.com> <86r4pqqwnm.fsf@ds4.des.no> <86ipat6n0o.fsf@ds4.des.no> <86y5joiyan.fsf@ds4.des.no> <20121003011607.5553fe48@gumby.homeunix.com> <86626raojm.fsf@ds4.des.no>

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On Wed, 03 Oct 2012 11:32:45 +0200
Dag-Erling Sm=F8rgrav wrote:

> RW <rwmaillists@googlemail.com> writes:
> > It doesn't compute it in a weird way for amd64 and most i386
> > systems. Where possible, get_cyclecount is just a wrapper for
> > rdtsc, which I think it will be for all the systems you quoted
> > (with the possible exception of virtualbox).
>=20
> No.  All the machines I tested it on had TSCs, but not all i386
> machines we support do, so get_cyclecount() is always a function call
> on i386. Look at the code, or heck, disassemble my kernel if you
> don't believe me.

It appears that it changed in April (Revision 220347), so if they were
all running 9.1, 9-stable or head then you're quite right.=20

I was looking at my local source where it's still conditional on
"tsc_present".



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