perf: enable coresight if enabled in MACHINE_FEATURES

Enable the CoreSight[1] functionality in perf[2] if 'coresight' is in the
MACHINE_FEATURES.

Note that enabling this will mean a dependency on the opencsd recipe,
which is currently part of meta-arm[3]. I don't think this is a problem
as this recipe is Arm-specific, and as this is a new feature the
behaviour is opt-in so shouldn't break any existing machines.

[1] https://docs.kernel.org/trace/coresight/coresight.html
[2] https://docs.kernel.org/trace/coresight/coresight-perf.html
[3] https://git.yoctoproject.org/meta-arm/tree/meta-arm/recipes-devtools/opencsd

Signed-off-by: Ross Burton <ross.burton@arm.com>
---
 meta/recipes-kernel/perf/perf.bb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

On Wed, Sep 3, 2025 at 8:49 AM Ross Burton via lists.openembedded.org
<ross.burton=arm.com@lists.openembedded.org> wrote:

> Enable the CoreSight[1] functionality in perf[2] if 'coresight' is in the
> MACHINE_FEATURES.
>
> Note that enabling this will mean a dependency on the opencsd recipe,
> which is currently part of meta-arm[3]. I don't think this is a problem
> as this recipe is Arm-specific, and as this is a new feature the
> behaviour is opt-in so shouldn't break any existing machines.
>

I don't have a problem with that arrangement. I could see if it was
widespread, or if the AB needed to use it on tests where meta-arm
wasn't available, then the cost of getting opencsd into core would
be worth it .. but since that isn't the cas and meta-arm being a
maintained and well behaved layer, I have no objections.

Would a comment above the PACKAGECONFIG help warn
someone that enabling it does add a dependency on meta-arm ?
Or do we expect that anyone trying this will already have meta-arm
and be knowledgeable enough to sort it out if they don't ?

Bruce


>
> [1] https://docs.kernel.org/trace/coresight/coresight.html
> [2] https://docs.kernel.org/trace/coresight/coresight-perf.html
> [3]
> https://git.yoctoproject.org/meta-arm/tree/meta-arm/recipes-devtools/opencsd
>
> Signed-off-by: Ross Burton <ross.burton@arm.com>
> ---
>  meta/recipes-kernel/perf/perf.bb | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/meta/recipes-kernel/perf/perf.bb b/meta/recipes-kernel/perf/
> perf.bb
> index 4f29bd5bbc3..194c30831dd 100644
> --- a/meta/recipes-kernel/perf/perf.bb
> +++ b/meta/recipes-kernel/perf/perf.bb
> @@ -10,7 +10,7 @@ HOMEPAGE = "
> https://perf.wiki.kernel.org/index.php/Main_Page"
>  LICENSE = "GPL-2.0-only"
>
>  # zstd is required for kernels 6.14+ when libelf-zstd is detected
> -PACKAGECONFIG ??= "python tui libunwind libtraceevent zstd"
> +PACKAGECONFIG ??= "python tui libunwind libtraceevent zstd
> ${@bb.utils.filter('MACHINE_FEATURES', 'coresight', d)}"
>  PACKAGECONFIG[dwarf] = ",NO_DWARF=1"
>  PACKAGECONFIG[perl] = ",NO_LIBPERL=1,perl"
>  PACKAGECONFIG[python] = ",NO_LIBPYTHON=1,python3
> python3-setuptools-native"
> --
> 2.43.0
>
>
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