linux-kernel - Re: [RFC PATCH] x86/cpu: Move sparsely used bit leafs into scattered features (was: Re: [PATCH 2/2] x86/cpufeature: Add CLZERO feature)

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Message-ID: <20151027032243.GB3946@nazgul.tnic>
Date:	Tue, 27 Oct 2015 04:22:43 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Andy Lutomirski <luto@...capital.net>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...nel.org>,
	"H. Peter Anvin" <hpa@...or.com>,
	Aravind Gopalakrishnan <aravind.gopalakrishnan@....com>,
	Tony Luck <tony.luck@...el.com>, X86 ML <x86@...nel.org>,
	ashok.raj@...el.com,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	linux-edac <linux-edac@...r.kernel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Andrew Lutomirski <luto@...nel.org>,
	Denys Vlasenko <dvlasenk@...hat.com>,
	Ross Zwisler <ross.zwisler@...ux.intel.com>,
	Dirk Brandewie <dirk.j.brandewie@...el.com>,
	Wan Zongshun <Vincent.Wan@....com>
Subject: Re: [RFC PATCH] x86/cpu: Move sparsely used bit leafs into scattered
 features (was: Re: [PATCH 2/2] x86/cpufeature: Add CLZERO feature)

On Mon, Oct 26, 2015 at 07:56:06PM -0700, Andy Lutomirski wrote:
> How few features in one leaf do we need before calling it scattered
> makes sense?  These four might make sense to keep as is...

Actually, according to hpa, all those leafs will be filled out gradually
as they're apparently going to be used for hw features. And it looks
like the AMD leaf is of the same type. So those all will be fleshed out
with time and we can keep them here, in cpufeature.h.

> ...whereas this looks totally reasonable.
> 
> FWIW, we have a ton of thses things.  Would it make sense to convert
> this to a text file giving features and their CPUID positions that
> generates the defines and the code to enumerate them?

Yeah, maybe. I'm not that really bothered by the current form too,
though.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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