Re: [dpdk-dev] [PATCH 1/2] config/arm: add non-SVE march for soc kunpeng930

[Jerin Jacob <jerinjacobk@gmail.com>]

On Wed, May 12, 2021 at 2:01 PM Chengwen Feng <fengchengwen@huawei.com> wrote:
>
> Currently, the soc_kunpeng930 declares '-march=armv8.2-a+crypto+sve',
> but some compiler doesn't recognize the march because it doesn't
> support sve.

Agree with the problem statement.

+ @Juraj Linkeš

>
> This patch adds '-march=armv8.2-a+crypto' before
> '-march=armv8.2-a+crypto+sve' so that:
> 1. If compiler doesn't support '-march=armv8.2-a+crypto+sve', then it
> will fallback supports 'armv8.2-a+crypto'.
> 2. If compiler supports '-march=armv8.2-a+crypto+sve', then it will
> compile SVE-related code.
>
> Fixes: 7cf32a22b240 ("config/arm: add Hisilicon kunpeng")
>
> Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
> ---
>  config/arm/meson.build | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/config/arm/meson.build b/config/arm/meson.build
> index 3f34ec9..fe6c29b 100644
> --- a/config/arm/meson.build
> +++ b/config/arm/meson.build
> @@ -158,7 +158,7 @@ implementer_hisilicon = {
>              ]
>          },
>          '0xd02': {
> -            'machine_args': ['-march=armv8.2-a+crypto+sve'],
> +            'machine_args': ['-march=armv8.2-a+crypto', '-march=armv8.2-a+crypto+sve'],

I think, this problem not specific to Kunpeng. I think, in order to
have a generic solution,
I think, we need to express something like [[armv8.2-a], [crypto],
[sve]] or so in the code and
any infra code can generate a working combination to avoid duplicating
the combination
manually in code and have some generic solution for all the platforms.

i.e
patch 1: Enable the infrastructure for auto probe based on compiler support.
patch 2: Fix existing machines including the Kunpeng.


>              'flags': [
>                  ['RTE_MACHINE', '"Kunpeng 930"'],
>                  ['RTE_ARM_FEATURE_ATOMICS', true],
> --
> 2.8.1
>