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Re: [PATCH][AArch64] Remove crypto extension from default for cortex-a53, cortex-a57
- From: Richard Earnshaw <rearnsha at arm dot com>
- To: Kyrill Tkachov <kyrylo dot tkachov at arm dot com>, Ramana Radhakrishnan <Ramana dot Radhakrishnan at arm dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>, Marcus Shawcroft <Marcus dot Shawcroft at arm dot com>
- Date: Tue, 18 Nov 2014 09:52:41 +0000
- Subject: Re: [PATCH][AArch64] Remove crypto extension from default for cortex-a53, cortex-a57
- Authentication-results: sourceware.org; auth=none
- References: <546A0AC1 dot 9060909 at arm dot com> <CAJA7tRapKphoSY=TizZoKc5UEw-OybVCOQwxZM5nGkmenDFK0g at mail dot gmail dot com> <546B13A4 dot 9070204 at arm dot com>
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.