Re: [PATCH v5 4/4] docs: Update custom_kernel docs for split up of kernel scripts and tools

["MOESSBAUER, Felix" <felix.moessbauer@siemens.com>]

On Wed, 2024-01-31 at 17:00 +0100, Stefan Koch wrote:
> Signed-off-by: Stefan Koch <stefan-koch@siemens.com>
> ---
>  doc/custom_kernel.md | 18 +++++++++++-------
>  1 file changed, 11 insertions(+), 7 deletions(-)
> 
> diff --git a/doc/custom_kernel.md b/doc/custom_kernel.md
> index 73987a5b..ce5f1bf7 100644
> --- a/doc/custom_kernel.md
> +++ b/doc/custom_kernel.md
> @@ -38,12 +38,18 @@ The linux-custom recipe provides support for:
>   7. Allow the name of the kernel image to be changed via
> `KERNEL_FILE` (defaults
>      to `vmlinuz`)
>  
> - 8. Produce a `linux-headers` package which includes kernel headers
> and kbuild
> -    scripts/tools
> + 8. Produce a `linux-headers` package which includes kernel headers
>  
> - 9. The `linux-headers` package shall support native and cross
> compiles of
> -    out-of-tree kernel modules. However, when built in cross-
> compilation mode,
> -    it cannot be used on the target so far.
> + 9. Produce a `linux-kbuild` package for both `target` and `host`
> arch
> +    which includes kbuild scripts and tools.
> +    Using `linux-kbuild` provides the package for the target and
> when
> +    cross building `linux-kbuild-native` provides the package for
> the host.
> +
> +    So the `linux-headers` package supports native and cross
> compiles of
> +    out-of-tree kernel modules. Even, when built in cross-
> compilation mode,
> +    it can be used on the target using the `linux-kbuild` package.
> +
> +    Only the `host` specific package is built automatically at cross
> builds.

Hi Stefan,

thanks for this series. I tested it and it already improves the
situation a lot (e.g. no native binaries in the arm64 packages).

Just a minor thing: When emulating the compilation of a kernel module
for an otherwise cross-compiled kernel, the build still fails as the
wrong dependency is attracted. I guess this can easily be fixed in
module.inc:

1. add a debian dependency to the "correct" kbuild package (e.g. the
one for arm64)
2. add an explicit debian build dependency to the kbuild package for
the non-native arch (e.g. arm64).

Only do that on non-cross (bitbake via the bitbake var, debian either
via bitbake or via a build-profile selector, e.g. "[cross]").

Best regards,
Felix

>  
>   10. Produce a `linux-libc-dev` package to support user-land builds
>  
> @@ -72,8 +78,6 @@ In the future, the recipe may be extended to:
>  
>   3. Be compatible with Ubuntu
>  
> - 4. When cross-building, generate kernel-headers for both host and
> target
> -
>  ## Examples
>  
>  The linux-custom recipe is currently used by the linux-mainline
> package and is

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