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From: Alex Vong <alexvong1995@gmail.com>
To: Tobias Geerinckx-Rice <me@tobias.gr>
Cc: development@libreboot.org, guix-devel@gnu.org
Subject: Re: Meltdown / Spectre
Date: Sun, 14 Jan 2018 23:11:25 +0800	[thread overview]
Message-ID: <87wp0kqxuq.fsf@gmail.com> (raw)
In-Reply-To: <807794bd-5262-8b36-1f9f-dd3a316928ff@tobias.gr> (Tobias Geerinckx-Rice's message of "Mon, 8 Jan 2018 22:51:00 +0100")

Tobias Geerinckx-Rice <me@tobias.gr> 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 —
> unfortunately for everyone everywhere — very (dis)functional indeed.
>
> (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 ‘non-free’[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 themselves?
>
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=microcode

  parent reply	other threads:[~2018-01-14 15:11 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-06 13:20 What do Meltdown and Spectre mean for libreboot x200 user? Alex Vong
2018-01-06 17:23 ` Mark H Weaver
2018-01-06 17:43 ` Meltdown / Spectre Leo Famulari
2018-01-06 20:15   ` Mark H Weaver
2018-01-07  6:38     ` Mark H Weaver
2018-01-07 21:29       ` Mark H Weaver
2018-01-09 21:39         ` Alex Vong
2018-01-10  4:59           ` Leo Famulari
2018-01-16 10:57             ` Ludovic Courtès
2018-01-19 22:06               ` Mark H Weaver
2018-01-20  0:17                 ` Leo Famulari
2018-01-21 16:26                   ` Mark H Weaver
2018-01-24 14:23                     ` Ludovic Courtès
2018-01-24 16:19                       ` Mark H Weaver
2018-01-26 22:05                       ` Mark H Weaver
2018-01-27 16:12                         ` Ludovic Courtès
2018-01-10 15:00           ` ng0
2018-01-08 10:30       ` Ludovic Courtès
2018-01-10  5:27       ` Leo Famulari
2018-01-07  2:44   ` Chris Marusich
2018-01-08 17:22     ` Katherine Cox-Buday
2018-01-08 18:26       ` Marius Bakke
2018-01-08 21:51         ` Tobias Geerinckx-Rice
2018-01-08 22:01           ` Tobias Geerinckx-Rice
2018-01-09 20:13           ` Katherine Cox-Buday
2018-01-09 21:18             ` Tobias Geerinckx-Rice
2018-01-10  5:26               ` Leo Famulari
2018-01-11 19:45                 ` Katherine Cox-Buday
2018-01-11 21:49                   ` Adonay Felipe Nogueira
2018-01-10 10:46               ` Tobias Platen
2018-01-10 17:20                 ` Leo Famulari
2018-01-10  6:43             ` Christopher Lemmer Webber
2018-01-10 18:41               ` Kei Kebreau
2018-01-16  3:58             ` Chris Marusich
2018-01-17 19:20               ` Gábor Boskovits
2018-01-14 15:11           ` Alex Vong [this message]
2018-01-09 23:10         ` Mark H Weaver
2018-01-10  5:04           ` Leo Famulari
2018-01-16 11:10             ` Ludovic Courtès
2018-01-17  2:38               ` Mike Gerwitz
2018-01-17 14:11                 ` Ludovic Courtès
2018-01-10  9:36           ` Chris Marusich
2018-01-10 11:49             ` Adonay Felipe Nogueira
2018-01-10 12:35               ` Tobias Platen
2018-01-10 14:04                 ` Gábor Boskovits
2018-01-12  0:25                   ` Marius Bakke
2018-01-15  8:07                   ` Pjotr Prins
2018-01-16  3:08                     ` Mike Gerwitz
2018-01-16 10:04                       ` Pjotr Prins
2018-01-12  7:39                 ` Chris Marusich

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