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From: Masahiro Yamada <masahiroy@kernel.org>
Date: Tue, 6 Feb 2024 05:50:58 +0900
Message-ID: <CAK7LNAQe5SounO60gyYE_3e-M0cAAgT=9jac_SLcR0i9BeEgDQ@mail.gmail.com>
Subject: Re: [PATCH] powerpc: add crtsavres.o to always-y instead of extra-y
To: Jan Stancek <jstancek@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>, Nicholas Piggin <npiggin@gmail.com>, 
	Christophe Leroy <christophe.leroy@csgroup.eu>, linuxppc-dev@lists.ozlabs.org, 
	Nathan Chancellor <nathan@kernel.org>, Nick Desaulniers <ndesaulniers@google.com>, Tom Rix <trix@redhat.com>, 
	linux-kernel@vger.kernel.org, llvm@lists.linux.dev
Content-Type: text/plain; charset="UTF-8"
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On Mon, Feb 5, 2024 at 10:22=E2=80=AFPM Jan Stancek <jstancek@redhat.com> w=
rote:
>
> On Mon, Feb 5, 2024 at 12:50=E2=80=AFPM Michael Ellerman <mpe@ellerman.id=
au> wrote:
> >
> > Jan Stancek <jstancek@redhat.com> writes:
> > > On Tue, Nov 21, 2023 at 10:51:34AM +1000, Nicholas Piggin wrote:
> > >>On Tue Nov 21, 2023 at 9:23 AM AEST, Masahiro Yamada wrote:
> > >>> crtsavres.o is linked to modules. However, as explained in commit
> > >>> d0e628cd817f ("kbuild: doc: clarify the difference between extra-y
> > >>> and always-y"), 'make modules' does not build extra-y.
> > >>>
> > >>> For example, the following command fails:
> > >>>
> > >>>   $ make ARCH=3Dpowerpc LLVM=3D1 KBUILD_MODPOST_WARN=3D1 mrproper p=
s3_defconfig modules
> > >>>     [snip]
> > >>>     LD [M]  arch/powerpc/platforms/cell/spufs/spufs.ko
> > >>>   ld.lld: error: cannot open arch/powerpc/lib/crtsavres.o: No such =
file or directory
> > >>>   make[3]: *** [scripts/Makefile.modfinal:56: arch/powerpc/platform=
s/cell/spufs/spufs.ko] Error 1
> > >>>   make[2]: *** [Makefile:1844: modules] Error 2
> > >>>   make[1]: *** [/home/masahiro/workspace/linux-kbuild/Makefile:350:=
 __build_one_by_one] Error 2
> > >>>   make: *** [Makefile:234: __sub-make] Error 2
> > >>>
> > >>
> > >>Thanks. Is this the correct Fixes tag?
> > >>
> > >>Fixes: d0e628cd817f ("powerpc/64: Do not link crtsavres.o in vmlinux"=
)
> > >>
> > >>Hmm, looks like LLD might just do this now automatically for us
> > >>too without --save-restore-funcs (https://reviews.llvm.org/D79977).
> > >>But we probably still need it for older versions, so we still need
> > >>your patch.
> > >
> > > Hi,
> > >
> > > I'm still seeing the error of crtsavres.o missing when building exter=
nal modules
> > > after "make LLVM=3D1 modules_prepare". Should it be built also in arc=
hprepare?
> >
> > Or modules_prepare?
> >
> > Example patch below.
>
> I tested your patch with my setup and that works for me as well.
>


Please note 'make ARCH=3Dpowerpc clean' will remove  '*.o'
files globally.


Kbuild promised you would still be able to compile external modules
after 'make clean' (until you run 'make mrproper'), but
that would not work in this case.

So, the external module support for powerpc
is broken in another way, already.


Perhaps, an easy workaround might be to change
the suffix, but I did not test it at all.

mv arch/powerpc/lib/crtsavres.o arch/powerpc/lib/crtsavres.o.do_not_remove_=
me


--=20
Best Regards
Masahiro Yamada