Date: Wed, 31 Jul 2013 20:01:03 +0200 From: "O. Hartmann" <ohartman@zedat.fu-berlin.de> To: Julian Stecklina <jsteckli@os.inf.tu-dresden.de> Cc: freebsd-current@freebsd.org Subject: Re: CURRENT: Ivy Bridge CPU (i3-3220) and Intel Bull Mountain RNG (options RDRAND_RNG) Message-ID: <20130731200103.4ea4055a@thor.walstatt.dyndns.org> In-Reply-To: <51F7C8B4.7070809@os.inf.tu-dresden.de> References: <20130730134635.3b6d7b31@thor.walstatt.dyndns.org> <51F7C8B4.7070809@os.inf.tu-dresden.de>
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--Sig_/6m5km9ZfgH.Rzgu0j_Ygpww Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Tue, 30 Jul 2013 16:07:48 +0200 Julian Stecklina <jsteckli@os.inf.tu-dresden.de> wrote: > On 07/30/2013 01:46 PM, O. Hartmann wrote: > >=20 > > I tried the new option "options RDRAND_RNG" on my SOHO server, > > equipted with a Intel i3-3220 "Ivy Brdige" CPU, which is supposed > > to have the Bull Mountain random number generator as a piece of > > hardware in its uncore. > > > > Enabling the kernel option doesn't reveal any presence of such a > > hardware number generator. "sysct kern.random" always reports=20 > >=20 > > kern.random.adaptors: yarrow > >=20 > > By intentionally disallowing yarrow via commenting out options > > YARROW_RNG, the box reports "no adaptors loaded". So, either this > > Ivy Bridge has been castrated and ripped off by Intel of its RNG or > > FreeBSD isn't capable of detecting it properly or I'm incapable of > > properly configure the kernel. >=20 > This might be Erratum BV54: >=20 > Problem: > On processors that support the RDRAND instruction, that capability > should be reported via the setting of CPUID.01H:ECX.RDRAND[bit 30]. > Due to this erratum, that bit will not be set, and the execution of > the RDRAND instruction will result in a #UD exception. >=20 > Implication: > Software will not be able to utilize the RDRAND instruction >=20 > http://www.intel.de/content/dam/www/public/us/en/documents/specification-= updates/3rd-gen-core-desktop-specification-update.pdf >=20 > Julian It seems, this "decoupling" of the adaptors has been removed/refected again! All those neat switches are gone with r253845 --Sig_/6m5km9ZfgH.Rzgu0j_Ygpww Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.20 (FreeBSD) iQEcBAEBAgAGBQJR+VDfAAoJEOgBcD7A/5N8U24H/ifrnefIrSP4rw8U5rnLmCvx cbuBOwQEvAFh0Fl2EI3dAXn6u5ivO1dYNoA2/0YNwxGN7ISqjPEXM1leBMjtuj8b jODQB/cdoP75BDkv2OCbm65VBU20VhBM+BQU1m05434XFXy7oy13wS14g230acDt Vzl3sf/1aWOQRVtTBFBVIlkhQf7xHblxZdzRnZdd/D2H13aVAZLG+pQ3SqMjrMGS E0dKU8YH+PqfUmbk0yDvAHDR0/RWQ9z9rxv0RAJlbvlHU6tljBP6Umew356oOssG bLhVZ/6uSbYv8cPLpZ/J1wgAppZILbIXYzBTUGE4g4zvB8qVAfxEUdq8my5DkmM= =nwHF -----END PGP SIGNATURE----- --Sig_/6m5km9ZfgH.Rzgu0j_Ygpww--
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