linux-kernel - Re: [PATCH v2] x86/lib/copy_user_64.S: Handle 4-byte nocache copy

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Date:	Tue, 09 Feb 2016 09:36:26 -0700
From:	Toshi Kani <toshi.kani@....com>
To:	Ingo Molnar <mingo@...nel.org>, Borislav Petkov <bp@...e.de>
Cc:	tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
	dan.j.williams@...el.com, ross.zwisler@...ux.intel.com,
	vishal.l.verma@...el.com, micah.parrish@....com,
	brian.boylston@....com, x86@...nel.org, linux-nvdimm@...ts.01.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] x86/lib/copy_user_64.S: Handle 4-byte nocache copy

On Tue, 2016-02-09 at 13:08 +0100, Ingo Molnar wrote:
> * Borislav Petkov <bp@...e.de> wrote:
> 
> > On Tue, Feb 09, 2016 at 12:27:32PM +0100, Ingo Molnar wrote:
> > > Btw., IIRC GAS is being silly about .L, i.e. there's a difference
> > > between these 
> > > two variants:
> > > 
> > >  .Lerror_entry_from_usermode_swapgs:
> > >  .L_error_entry_from_usermode_swapgs:
> > > 
> > > the latter would be easier to read, but does not result in a local
> > > label last I 
> > > checked.
> > > 
> > > Right?
> > 
> > Seems to build ok here with "GNU assembler (GNU Binutils)
> > 2.26.51.20151207".
> > Perhaps some bug with older gas...?
> 
> Hm, indeed - I just tried it too.
> 
> This means that the (slightly) more readable .L_ prefix is preferred.

Thanks for the suggestions!  I will update the patch accordingly. 
-Toshi