linux-kernel - Re: [RFC PATCH 0/3] Add Documentation for /proc/cpuinfo flags

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Message-ID: <20200610203537.GT14118@zn.tnic>
Date:   Wed, 10 Jun 2020 22:35:37 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Kyung Min Park <kyung.min.park@...el.com>
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org, tglx@...utronix.de,
        mingo@...hat.com, hpa@...or.com, gregkh@...uxfoundation.org,
        ak@...ux.intel.com, dave.hansen@...el.com, tony.luck@...el.com,
        ravi.v.shankar@...el.com, ricardo.neri@...el.com
Subject: Re: [RFC PATCH 0/3] Add Documentation for /proc/cpuinfo flags

On Wed, Jun 10, 2020 at 01:06:58PM -0700, Kyung Min Park wrote:
> Include two instances of features for which there are not implemented
> use cases in the kernel.
> 
> Patch 1 creates a new documentation for /proc/cpuinfo flags bits.
> Patch 2 adds X86_FEATURE_SERIALIZE.
> Patch 3 adds X86_FEATURE_TSXLDTRK.
> 
> This RFC series has been reviewed by Dave Hansen.

Yeah, and he and I talked about this on IRC. If you really want to dump
CPUID to see what's there, we should do a userspace tool in tools/ or
even use the ones which are already out there: x86info, cpuid, ...

Just adding X86_FEATURE_* flags without usage in the kernel makes no
sense and will cause unnecessary bloat and doesn't help one bit because
userspace simply calls CPUID directly.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette