From owner-freebsd-security@FreeBSD.ORG  Wed Sep 19 18:28:42 2012
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Date: Wed, 19 Sep 2012 19:28:36 +0100
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Subject: Re: Collecting entropy from device_attach() times.
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On Tue, 18 Sep 2012 23:14:22 +0200
Pawel Jakub Dawidek wrote:

> Hi.
>=20

> The patch is here:
>=20
> 	http://people.freebsd.org/~pjd/patches/harvest_device_attach.patch
>=20
> Comments?
>=20

+	attachtime =3D get_cyclecount() - attachtime;

the above line is redundant since random_harvest() already contains a
call to get_cyclecount().



On Wed, 19 Sep 2012 17:28:46 +0200
Dag-Erling Sm=F8rgrav wrote:

> You can't rely on the existence of a TSC.  I would suggest using the
> fractional part of binuptime instead.

get_cyclecount() is supposed to be platform independent and should
fall-back to nanotime(9) if TSC or equivalent is absent.=20