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From: Michael Ellerman <mpe@ellerman.id.au>
To: Jan Stancek <jstancek@redhat.com>, Nicholas Piggin <npiggin@gmail.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>, 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, jstancek@redhat.com
Subject: Re: [PATCH] powerpc: add crtsavres.o to always-y instead of extra-y
In-Reply-To: <ZbjHTMhQ4Z9lRR6L@t14s>
References: <20231120232332.4100288-1-masahiroy@kernel.org>
 <CX42TU4QHS1Z.A0UUHMDAMZOL@wheely> <ZbjHTMhQ4Z9lRR6L@t14s>
Date: Mon, 05 Feb 2024 22:50:17 +1100
Message-ID: <87v873870m.fsf@mail.lhotse>
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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=powerpc LLVM=1 KBUILD_MODPOST_WARN=1 mrproper ps3_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/platforms/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 external modules
> after "make LLVM=1 modules_prepare". Should it be built also in archprepare?

Or modules_prepare?

Example patch below.

cheers


diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 051247027da0..82cdef40a9cd 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -59,6 +59,11 @@ ifeq ($(CONFIG_PPC64)$(CONFIG_LD_IS_BFD),yy)
 KBUILD_LDFLAGS_MODULE += --save-restore-funcs
 else
 KBUILD_LDFLAGS_MODULE += arch/powerpc/lib/crtsavres.o
+
+crtsavres_prepare: scripts
+	$(MAKE) $(build)=arch/powerpc/lib arch/powerpc/lib/crtsavres.o
+
+modules_prepare: crtsavres_prepare
 endif
 
 ifdef CONFIG_CPU_LITTLE_ENDIAN