V2 [PATCH] x86: Use _rdtsc intrinsic for HP_TIMING_NOW

[Adhemerval Zanella]

On 02/10/2018 13:56, H.J. Lu wrote:
> On Tue, Oct 2, 2018 at 6:45 AM H.J. Lu <hjl.tools@gmail.com> wrote:
>>
>> On Tue, Oct 2, 2018 at 6:15 AM Adhemerval Zanella
>> <adhemerval.zanella@linaro.org> wrote:
> 
>>> I am not very found of cross abi includes like this one, wouldn't be better
>>> to create a 'sysdeps/x86/hp-timing.h' and for 32-bit use _rdtsc iff
>>> __i686__ is defined otherwise include generic header?
>>
>> I can do that.
> 
> Here is the V2 patch.  OK for master?
> 

> NB: Checking if __i686__ isn't sufficient since __i686__ may not be
> defined when building for i686 class processors.

Right, it seems gcc does not define it for -march newer than pentium4.

> diff --git a/sysdeps/i386/i586/init-arch.h b/sysdeps/i386/i586/isa.h
> similarity index 89%
> rename from sysdeps/i386/i586/init-arch.h
> rename to sysdeps/i386/i586/isa.h
> index 72fb46c61e..a2b5d585d4 100644
> --- a/sysdeps/i386/i586/init-arch.h
> +++ b/sysdeps/i386/i586/isa.h
> @@ -1,4 +1,4 @@
> -/* Copyright (C) 2015-2018 Free Software Foundation, Inc.
> +/* Copyright (C) 2018 Free Software Foundation, Inc.
>     This file is part of the GNU C Library.
>  
>     The GNU C Library is free software; you can redistribute it and/or
> @@ -15,5 +15,9 @@
>     License along with the GNU C Library; if not, see
>     <http://www.gnu.org/licenses/>.  */
>  
> +#ifndef _isa_h
> +#define _isa_h
> +

Not sure if this is explicit on our coding rules, but usually we
use uppercase caps for preprocessor guards.  I think it requires
a one-line description as well (same for other isa.h files).

> -#ifndef _HP_TIMING_H
> -#define _HP_TIMING_H	1
> +#include <isa.h>
> +
> +#if MINIMUM_ISA == 686 || MINIMUM_ISA == 8664
> +# ifndef _HP_TIMING_H
> +#  define _HP_TIMING_H	1
> +

The include guard inside the MINIMUM_ISA check seems off, why do
you need it?