From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Vong Subject: Re: Meltdown / Spectre Date: Sun, 14 Jan 2018 23:11:25 +0800 Message-ID: <87wp0kqxuq.fsf@gmail.com> References: <874lnzcedp.fsf@gmail.com> <20180106174358.GA28436@jasmine.lan> <87lghapeu5.fsf@gmail.com> <87incc6z9o.fsf@gmail.com> <87fu7g436e.fsf@fastmail.com> <807794bd-5262-8b36-1f9f-dd3a316928ff@tobias.gr> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Return-path: Received: from eggs.gnu.org ([2001:4830:134:3::10]:51903) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eajwi-0005Cq-HC for guix-devel@gnu.org; Sun, 14 Jan 2018 10:11:41 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eajwf-0001JR-C1 for guix-devel@gnu.org; Sun, 14 Jan 2018 10:11:40 -0500 Received: from mail-pl0-x242.google.com ([2607:f8b0:400e:c01::242]:45858) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1eajwf-0001Ik-6J for guix-devel@gnu.org; Sun, 14 Jan 2018 10:11:37 -0500 Received: by mail-pl0-x242.google.com with SMTP id p5so1984599plo.12 for ; Sun, 14 Jan 2018 07:11:37 -0800 (PST) In-Reply-To: <807794bd-5262-8b36-1f9f-dd3a316928ff@tobias.gr> (Tobias Geerinckx-Rice's message of "Mon, 8 Jan 2018 22:51:00 +0100") List-Id: "Development of GNU Guix and the GNU System distribution." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guix-devel-bounces+gcggd-guix-devel=m.gmane.org@gnu.org Sender: "Guix-devel" To: Tobias Geerinckx-Rice Cc: development@libreboot.org, guix-devel@gnu.org Tobias Geerinckx-Rice writes: > Hej Marius, > > [I see this is being CC'd to @libreboot.org. I'm answering only as a GNU > Guix user and contributor, and assume people who live and breathe this > stuff will find plenty of holes in my opinion. Which this is.] > > Marius Bakke wrote on 08/01/18 at 19:26: >> In my opinion, CPU microcode falls under "non-functional data", as >> expressly permitted by the GNU FSDG. > > I'm not sure how tongue-in-cheek this is, so I'm not sure how to > respond. I hope nobody on the Internet is wrong^Wseriously suggesting > that microcode or any other firmware isn't machine code and =E2=80=94 > unfortunately for everyone everywhere =E2=80=94 very (dis)functional inde= ed. > > (Don't get me wrong: I wish it weren't so, or that there were some sort > of commonly-agreed-upon wink-nudge fiction that it wasn't. If there is, > then Debian isn't playing along: microcode blobs are =E2=80=98non-free= =E2=80=99[0].) > > I think the real and thornier question for GuixSD is: if the recent CPU > vulnerabilities require a microcode update to fully mitigate, then how > do we square not recommending proprietary globs like this in official > channels with giving users all knowledge required to decide for themselve= s? > For this particular question, I think we can point users to this discussion thread in the news section for example. Then they can decide for themselves what to do. I think this is close to the best thing we can do now. >> It is not required for the processor to function, it is merely *a >> posteriori* data that the CPU can use to fix erratic behaviour. > > AIUI, at least on x86 CPUs, the microcode *is* a large and/or functional > part of the processor. I suspect that's the case for most sufficiently > modern (complex) chips, but it's not my field. > Agree, in my assembly programming course, the lecturer mentioned that (if I recall correctly) a mircrocode update can bring new instruction set to a CPU, so it is a very programmable part of the CPU. > Kind regards, > > T G-R > > [0]: https://lists.debian.org/debian-devel/2012/11/msg00109.html, > https://packages.debian.org/search?keywords=3Dmicrocode