Re: [dpdk-dev] [PATCH v4 1/2] config/arm: select most suitable -march for kunpeng soc

[Jerin Jacob <jerinjacobk@gmail.com>]

On Thu, May 13, 2021 at 6:41 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.
>
> To solve this bug we use the following scheme:
> 1. Define 'march_base' tuple which defines support march, it should
> arrange from lower to higher.
> e.g. 'march_base' : ['-march=armv8-a', '-march=armv8.2-a']
> 2. Define 'march_feature' tuple which defines support feature.
> e.g. 'march_feature' : ['crypto', 'sve']
> 3. Select the most suitable march+feature combination based on
> 'march_base' and 'march_feature' tuples.
> 4. Use the selected march+feature combination as the default
> machine_args.
>
> Fixes: 7cf32a22b240 ("config/arm: add Hisilicon kunpeng")
>
> Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
> ---
>  config/arm/meson.build | 27 +++++++++++++++++++++++++--
>  1 file changed, 25 insertions(+), 2 deletions(-)
>
> diff --git a/config/arm/meson.build b/config/arm/meson.build
> index 3f34ec9..8551a80 100644
> --- a/config/arm/meson.build
> +++ b/config/arm/meson.build
> @@ -149,7 +149,9 @@ implementer_hisilicon = {
>      ],
>      'part_number_config': {
>          '0xd01': {
> -            'machine_args': ['-march=armv8.2-a+crypto', '-mtune=tsv110'],
> +            'march_base' : ['-march=armv8-a', '-march=armv8.2-a'],

Another target has the same issue. Could you fix that all together as
it is generic problem in the existing infrastructure.


> +            'march_feature' : ['crypto'],
> +            'machine_args': ['-mtune=tsv110'],
>              'flags': [
>                  ['RTE_MACHINE', '"Kunpeng 920"'],
>                  ['RTE_ARM_FEATURE_ATOMICS', true],
> @@ -158,7 +160,9 @@ implementer_hisilicon = {
>              ]
>          },
>          '0xd02': {
> -            'machine_args': ['-march=armv8.2-a+crypto+sve'],
> +            'march_base' : ['-march=armv8-a', '-march=armv8.2-a'],
> +            'march_feature' : ['crypto', 'sve'],
> +            'machine_args': [],
>              'flags': [
>                  ['RTE_MACHINE', '"Kunpeng 930"'],
>                  ['RTE_ARM_FEATURE_ATOMICS', true],
> @@ -449,8 +453,27 @@ else
>      # add/overwrite flags in the proper order
>      dpdk_flags = flags_common + implementer_config['flags'] + part_number_config.get('flags', []) + soc_flags
>
> +    # select the most suitable march+feature combination
> +    machine_march = []
> +    if part_number_config.has_key('march_base')
> +        foreach arch: part_number_config['march_base']
> +            if cc.has_argument(arch)
> +                machine_march = arch # Set the higher supported arch as possible
> +            endif
> +        endforeach
> +    endif
> +    if part_number_config.has_key('march_feature')
> +        foreach feature: part_number_config['march_feature']
> +            tmp_machine_march = machine_march + '+' + feature
> +            if cc.has_argument(tmp_machine_march)
> +                machine_march = tmp_machine_march # Set the more supported feature as possible
> +            endif
> +        endforeach
> +    endif
> +
>      # apply supported machine args
>      machine_args = [] # Clear previous machine args
> +    machine_args += machine_march
>      foreach flag: part_number_config['machine_args']
>          if cc.has_argument(flag)
>              machine_args += flag
> --
> 2.8.1
>