[PATCH] um: let 'make clean' properly clean underlying SUBARCH as well

[Geert Uytterhoeven]

Hi Johannes,

On Thu, 8 May 2025 at 07:29, Johannes Berg <johannes at sipsolutions.net> wrote:
> On Wed, 2025-05-07 at 15:38 -0600, Shuah Khan wrote:
> > My workflow:
> >
> > - Build kernel on x86_64 with CONFIG_AMD_MEM_ENCRYPT enabled
> >
> > - Check for arch/x86/realmode/rm/pasyms.h
> >    ls arch/x86/realmode/rm/pasyms.h
> >       arch/x86/realmode/rm/pasyms.h
> >
> > - make ARCH=um O=/linux/build
> >
> >    This patch cleans the source tree, but doesn't remove
> >    arch/x86/realmode/rm/pasyms.h
> >
> > - ls arch/x86/realmode/rm/pasyms.h
> >       arch/x86/realmode/rm/pasyms.h
>
> Is that even _expected_ to work? If you have x86 built first, I'd almost
> expect you to have to do "make ARCH=x86 mrproper" before building
> another ARCH. I don't see how ARCH=um would know how to do a full clean
> up of ARCH=x86, unless this is somehow arch-independent?
>
> Or maybe that's not an issue with other architectures because UML is
> special in that it uses parts of x86?

Probably.
I only use my linux-next source tree for fixing reported build issues on
various architectures, and I never use make clean/mrproper.  Works fine.

> Though I guess the patch here should make it do that, more or less, but
> it can't, likely because you're also switching from in-tree build to O=
> build?

Yeah, mixing in-tree and out-of-tree builds causes issues.
Never build in-tree in a source tree you use with O= (except for
e.g. "make tags").

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds