linux-kernel - Re: [PATCH] powerpc: clean vdso32 and vdso64 directories

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Message-ID: <CAK7LNAQ4KD4zG2Me7RhsJNOXrMqDOHpd2YNoSPH4CZ63HXtqpQ@mail.gmail.com>
Date:   Wed, 17 Nov 2021 23:58:52 +0900
From:   Masahiro Yamada <masahiroy@...nel.org>
To:     Christophe Leroy <christophe.leroy@...roup.eu>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>,
        Ard Biesheuvel <ardb@...nel.org>,
        Nicholas Piggin <npiggin@...il.com>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>
Subject: Re: [PATCH] powerpc: clean vdso32 and vdso64 directories

On Wed, Nov 17, 2021 at 12:38 AM Christophe Leroy
<christophe.leroy@...roup.eu> wrote:
>
> Hi Masahiro,
>
> Le 09/11/2021 à 19:50, Masahiro Yamada a écrit :
> > Since commit bce74491c300 ("powerpc/vdso: fix unnecessary rebuilds of
> > vgettimeofday.o"), "make ARCH=powerpc clean" does not clean up the
> > arch/powerpc/kernel/{vdso32,vdso64} directories.
> >
> > Use the subdir- trick to let "make clean" descend into them.
> >
> > Fixes: bce74491c300 ("powerpc/vdso: fix unnecessary rebuilds of vgettimeofday.o")
> > Signed-off-by: Masahiro Yamada <masahiroy@...nel.org>
> > ---
> >
> >   arch/powerpc/kernel/Makefile | 3 +++
> >   1 file changed, 3 insertions(+)
> >
> > diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
> > index 0e3640e14eb1..5fa68c2ef1f8 100644
> > --- a/arch/powerpc/kernel/Makefile
> > +++ b/arch/powerpc/kernel/Makefile
> > @@ -196,3 +196,6 @@ clean-files := vmlinux.lds
> >   # Force dependency (incbin is bad)
> >   $(obj)/vdso32_wrapper.o : $(obj)/vdso32/vdso32.so.dbg
> >   $(obj)/vdso64_wrapper.o : $(obj)/vdso64/vdso64.so.dbg
> > +
> > +# for cleaning
> > +subdir- += vdso32 vdso64
> >
>
> This patch make me think about one thing I would have liked to do, but I
> don't know Makefiles well enough to be able to do it. You could probably
> help me with it.
>
> vdso32 and vdso64 contain a lot of redundant sources. I would like to
> merge them into a new single directory, let say 'vdso', and use the
> files in that directory to build both vdso32.so and vdso64.so. I have a
> feeling that x86 is doing it that way, but I've not been able to figure
> out how to build two objects using the same C/S files.
>
> Thanks
> Christophe

Changing the code as follows might work.

$(obj-vdso32): %-32.o: %.S FORCE
          $(call if_changed_dep,vdso32as)




-- 
Best Regards
Masahiro Yamada