linux-kernel - Re: [PATCH v7 18/18] x86/fsgsbase/64: Add documentation for FSGSBASE

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Date:   Mon, 17 Jun 2019 07:18:45 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     "Bae, Chang Seok" <chang.seok.bae@...el.com>
cc:     Andy Lutomirski <luto@...nel.org>, Ingo Molnar <mingo@...nel.org>,
        "H . Peter Anvin" <hpa@...or.com>, Andi Kleen <ak@...ux.intel.com>,
        "Shankar, Ravi V" <ravi.v.shankar@...el.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Randy Dunlap <rdunlap@...radead.org>,
        "x86@...nel.org" <x86@...nel.org>, Jonathan Corbet <corbet@....net>
Subject: Re: [PATCH v7 18/18] x86/fsgsbase/64: Add documentation for
 FSGSBASE

Chang,

On Mon, 17 Jun 2019, Bae, Chang Seok wrote:

Can you please use proper quoting style?

> On Jun 16, 2019, at 15:00, Thomas Gleixner <tglx@...utronix.de<mailto:tglx@...utronix.de>> wrote:
> > 
> > > -GCC version 4.6.4 and newer provide instrinsics for the FSGSBASE
> > > +GCC version 6 and newer provide instrinsics for the FSGSBASE
> > > instructions. Clang supports them as well.
> > > 
> > >   =================== ===========================
> > > @@ -141,7 +141,7 @@ code and the compiler option -mfsgsbase has to be added.
> > > Compiler support for FS/GS based addressing
> > > -------------------------------------------
> > > 
> > > -GCC version 6 and newer provide support for FS/GS based addressing via
> > > +GCC version 4.6.4 and newer provide support for FS/GS based addressing via
> > > Named Address Spaces. GCC implements the following address space
> > > identifiers for x86:
> > > 
> > That's close to what I pushed out earlier into tip WIP.x86/cpu
> >  
> >  Please check against that version including the Clang part about address
> >  spaces close to the end.
> 
> 
> It is actually rebased on the tip branch (WIP.x86/cpu).

I have no idea what you mean with that. That patch you sent (see above) did
not apply against WIP.x86/cpu and claims exactly what I changed and pushed
out. Now you say it's the other way round:

> The point is the two GCC version indications are opposite right now:
>  - Intrinsics support begins from v4.6.4, not v6.
> - Address space identifiers support starts from v6, instead of v4.6.4

Is it really so hard to send proper patches like the below or if that's not
possible write up the facts so someone else can turn it into a proper patch
like the one below:

Thanks,

	tglx

8<--------------------
diff --git a/Documentation/x86/x86_64/fsgs.rst b/Documentation/x86/x86_64/fsgs.rst
index d5588e00b939..380c0b5ccca2 100644
--- a/Documentation/x86/x86_64/fsgs.rst
+++ b/Documentation/x86/x86_64/fsgs.rst
@@ -125,7 +125,7 @@ FSGSBASE instructions enablement
 FSGSBASE instructions compiler support
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-GCC version 6 and newer provide instrinsics for the FSGSBASE
+GCC version 4.6.4 and newer provide instrinsics for the FSGSBASE
 instructions. Clang supports them as well.
 
   =================== ===========================
@@ -141,7 +141,7 @@ code and the compiler option -mfsgsbase has to be added.
 Compiler support for FS/GS based addressing
 -------------------------------------------
 
-GCC version 4.6.4 and newer provide support for FS/GS based addressing via
+GCC version 6 and newer provide support for FS/GS based addressing via
 Named Address Spaces. GCC implements the following address space
 identifiers for x86: