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

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Message-ID: <ea40f7c4-ec8d-4be5-8f8c-bbd11ab07252@email.android.com>
Date:	Mon, 01 Sep 2014 11:48:03 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Henrique de Moraes Holschuh <hmh@....eng.br>
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?

No, it is worse to rename it and have older kernels behave differently.  Kernel options are basically super obscure to most people anyway.

On September 1, 2014 10:43:22 AM PDT, Henrique de Moraes Holschuh <hmh@....eng.br> wrote:
>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.

-- 
Sent from my mobile phone.  Please pardon brevity and lack of formatting.
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