linux-kernel - Re: early microcode: how to disable at runtime?

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Message-ID: <20140901174322.GA15533@khazad-dum.debian.net>
Date:	Mon, 1 Sep 2014 14:43:22 -0300
From:	Henrique de Moraes Holschuh <hmh@....eng.br>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	Borislav Petkov <bp@...en8.de>, Fenghua Yu <fenghua.yu@...el.com>,
	linux-kernel@...r.kernel.org
Subject: Re: early microcode: how to disable at runtime?

On Mon, 01 Sep 2014, H. Peter Anvin wrote:
> On 08/31/2014 10:13 PM, Borislav Petkov wrote:
> > On Sun, Aug 31, 2014 at 05:11:26PM -0300, Henrique de Moraes Holschuh wrote:
> >>> Probably more like something more like arch/x86/boot/cmdline.c.  Maybe
> >>> we could even make it sharable.
> >>
> >> Looks like that would work, yes.
> > 
> > Guys, guys, please relax and check the code first: "dis_ucode_ldr".
> > 
> 
> Yeah.  It is an absolutely horrific option name (something like
> "noearlyucode" would have been so much nicer; we generally use the no-
> prefix and no underscores) but I should have objected to that one much
> sooner.

It wasn't properly documented, it is obscure as all heck, and early
microcode updates active by default is a very recent development on distros.

You cannot even find "dis_ucode_ldr" being cited by anyone through google
searches.

I believe it is actually possible to fix this still: either by directly
renaming, or by using a deprecation period and testing for a new name and
the "dis_ucode_ldr" name.

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh
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