Re: [OE-core] [PATCH v5 11/15] kernel.bbclass: Export artifacts needed for out-of-tree Rust compilation

[Harish Sadineni <Harish.Sadineni@windriver.com>]

On 1/29/2026 10:09 PM, Sadineni, Harish via lists.openembedded.org wrote:
> From: Yoann Congal <yoann.congal@smile.fr>
>
> Publish artifacts from kernel compilation to allow out-of-tree Rust
> compilation:
> * scripts/target.json: target definition: architecture, ABI, compiler
>    options, ...
> * rust/: the crates compiled by the kernel available to
>    out-of-tree-modules
Hi Yoann,

I am dropping this patch “kernel.bbclass: Export artifacts needed for 
out-of-tree Rust compilation” from my v6 patch series.

Without this patch, target.json and the rust/ directory were already 
getting published for x86_64. On arm64, target.json will not be created, 
yet the module is still generated and works fine.

When building rust-out-f-tree-module for arm64 with this patch applied, 
it emits a warning that Out-of-tree rust modules build will fail due to 
a missing target.json in kernel. However, in practice, the build 
completes successfully.

I have tested without this patch on both arm64 and x86_64, both tests 
were successful.

So, this patch does not appear to be necessary. Are you OK with dropping 
this patch?

I have pushed the updated changes to the below oe-contrib branch:
https://git.openembedded.org/openembedded-core-contrib/log/?h=deepesh/rust-in-kernel-v6

Additionally, I have extended the ccache disabling to make-mod-scripts 
(as part of "kernel: Disable ccache when kernel rust support is enabled" 
patch) and updated "meta-skeleton: Add rust-out-of-tree-module recipe" 
to align with the new changes.

Thanks,
Harish
> Signed-off-by: Yoann Congal <yoann.congal@smile.fr>
> Signed-off-by: Harish Sadineni <Harish.Sadineni@windriver.com>
> ---
>   meta/classes-recipe/kernel.bbclass | 18 ++++++++++++++++++
>   1 file changed, 18 insertions(+)
>
> diff --git a/meta/classes-recipe/kernel.bbclass b/meta/classes-recipe/kernel.bbclass
> index 30a10b0801..dfb8604a68 100644
> --- a/meta/classes-recipe/kernel.bbclass
> +++ b/meta/classes-recipe/kernel.bbclass
> @@ -632,6 +632,24 @@ do_shared_workdir () {
>   		cp -r scripts/gcc-plugins ${kerneldir}/scripts
>   	fi
>   
> +	if ${@bb.utils.contains("DISTRO_FEATURES", "rust-kernel", "true", "false", d)}; then
> +		# Copy target.json file needed for out-of-tree rust modules
> +		if [ -e scripts/target.json ]; then
> +			bbnote "Copying scripts/target.json"
> +			mkdir -p ${kerneldir}/scripts
> +			cp scripts/target.json ${kerneldir}/scripts
> +		else
> +			bbwarn "scripts/target.json not found in compiled kernel. Out-of-tree rust modules will fail to build."
> +		fi
> +
> +		# Copy rust/ needed by out-of-tree module (firstly for the core rust crate)
> +		if [ -e rust/ ]; then
> +			bbnote "Copying rust/"
> +			cp -r rust ${kerneldir}/
> +		else
> +			bbwarn "rust/ not found in compiled kernel. Out-of-tree rust modules will fail to build."
> +		fi
> +	fi
>   }
>   
>   # We don't need to stage anything, not the modules/firmware since those would clash with linux-firmware
>
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