Re: Kbuilds and Makefiles in building the kernel

Nagy =C3=81brah=C3=A1m Zsombor <[email protected]> =E6=96=BC 2025=E5=B9=
=B411=E6=9C=8828=E6=97=A5 =E9=80=B1=E4=BA=94 =E4=B8=8A=E5=8D=881:37=E5=AF=
=AB=E9=81=93=EF=BC=9A
>
> On Thu, 2025-11-27 at 19:26 +0800, Nick Huang wrote:
> > Abraham Zsombor Nagy <[email protected]> =E6=96=BC 2025=E5=B9=B411=E6=
=9C=8827=E6=97=A5=E9=80=B1=E5=9B=9B =E4=B8=8B=E5=8D=886:43=E5=AF=AB=E9=81=
=93=EF=BC=9A
> > >
> > > Hello,
> > >
> > > https://docs.kernel.org/kbuild/makefiles.html#the-kbuild-files stat
> > > es
> > > that when a directory contains a Kbuild file, the Makefile is
> > > skipped in
> > > that directory.
> > >
> > > It feels to me that both files are in use e.g. under arch/x86/
> > > directory.
> > >
> > > I'm trying to see what files are the core of the kernel and what
> > > files
> > > can be configured for x86 by partially parsing the Makefiles and
> > > the
> > > Kbuild files. Would it be sufficient to parse them as:
> > >
> > > if file =3D=3D "Makefile" or file =3D=3D "Kbuild":
> > >
> > >  > parse(file)
> > >
> > > or it should prefer the Kbuild file when present, or it is using
> > > some
> > > other logic?
> > >
> > > Sincerely,
> > >
> > > Abraham Nagy
> > >
> > >
> >
> > Hi  Abraham Zsombor Nagy
> > What functionality are you trying to add that would require modifying
> > the Makefile or Kbuild?
> >
> > Sincerely,
> > Nick Huang
>
> Hi Nick,
>
> I'm not modifying the build files, only writing a script that walks
> through the source tree and parses Makefiles and Kbuild files to list
> what source files are linked to the kernel by default and by CONFIG_*
> options. This is to see what to read through to get a basic
> understanding of the kernel at a given config.
>
> As I understand the documentation linked above, I should skip Makefiles
> when Kbuild files are present in a directory, but Makefiles feels to
> have important lines too.
>
> The approach is something like to extract object files and
> subdirectories from lines that start with python regex "^\S+-y" or
> "^\S+-\$\(CONFIG.*\)".
>
> Sincerely,
> Abraham
>
>

Hi Abraham
You can use git grep -n "CONFIG_**" to find the files you need.

Sincerely,
Nick