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Re: [PATCH][AArch64] Remove crypto extension from default for cortex-a53, cortex-a57


On 18/11/14 09:38, Kyrill Tkachov wrote:
> 
> On 17/11/14 16:59, Ramana Radhakrishnan wrote:
>> On Mon, Nov 17, 2014 at 2:48 PM, Kyrill Tkachov <kyrylo.tkachov@arm.com> wrote:
>>> Hi all,
>>>
>>> Some configurations of Cortex-A53 and Cortex-A57 don't ship with crypto,
>>> so enabling it by default for -mcpu=cortex-a53 and cortex-a57 is
>>> inappropriate.
>>>
>>> Tested aarch64-none-elf. Reminder that at the moment all the crypto
>>> extension does is enable the use of the ACLE crypto intrinsics in arm_neon.h
>>>
>>> Ok for trunk?
>> I can't ok this but ...
>>
>> Since we've changed behaviour from 4.9 I think it warrants an entry in
>> changes.html for 5.0
> 
> Makes sense.
> Here's what I propose.
> 
> Ok?
> 
> Kyrill
> 
>>
>> Ramana
>>
>>> Thanks,
>>> Kyrill
>>>
>>> 2014-11-17  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
>>>
>>>      * config/aarch64/aarch64-cores.def (cortex-a53): Remove
>>>      AARCH64_FL_CRYPTO from feature flags.
>>>      (cortex-a57): Likewise.
>>>      (cortex-a57.cortex-a53): Likewise.
> 
> 
> www-docs-a50-crypto.patch
> 
> 
> Index: htdocs/gcc-5/changes.html
> ===================================================================
> RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-5/changes.html,v
> retrieving revision 1.23
> diff -U 3 -r1.23 changes.html
> --- htdocs/gcc-5/changes.html	14 Nov 2014 10:49:51 -0000	1.23
> +++ htdocs/gcc-5/changes.html	17 Nov 2014 17:46:41 -0000
> @@ -257,6 +257,13 @@
>         Alternatively it can be enabled by default by configuring GCC with the
>         <code>--enable-fix-cortex-a53-835769</code> option.
>       </li>
> +     <li> The cryptographic extensions to the ARMv8-A architecture are no
> +       longer enabled by default when specifying the
> +       <code>-mcpu=cortex-a53</code>, <code>-mcpu=cortex-a57</code> or
> +       <code>-mcpu=cortex-a57.cortex-a53</code> options.  To enable these
> +       extensions add the <code>+crypto</code> extension to your given
> +       <code>-mcpu</code> or <code>-march</code> options' value.
> +     </li>
>  
>     </ul>
>  
> 

I'd suggest:

	The optional cryptographic extensions ...

But otherwise it looks fine to me.

R.


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