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

["Koch, Stefan" <stefan-koch@siemens.com>]

On Thu, 2024-02-01 at 10:35 +0000, Moessbauer, Felix (T CED OES-DE)
wrote:
> 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:
> 

I have successful built a module that uses linux-module/module.inc

That works either using cross-compilation or using QEMU based target
compilation.

> 1. add a debian dependency to the "correct" kbuild package (e.g. the
> one for arm64)
Was automatically used (:arm64) when ISAR_CROSS_COMPILE = "0" otherwise
(:amd64)
> 2. add an explicit debian build dependency to the kbuild package for
> the non-native arch (e.g. arm64).
Was unchanged
> 
> Only do that on non-cross (bitbake via the bitbake var, debian either
> via bitbake or via a build-profile selector, e.g. "[cross]").
Was unchanged, too
> 
> Best regards,
> Felix
> 
Stefan
> >  
> >   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
> 
> -- 
> Siemens AG, Technology
> Linux Expert Center
> 
> 

-- 
Stefan Koch
Siemens AG
www.siemens.com