linux-kernel - Re: [PATCH 6.1&6.6 0/3] kbuild: Avoid weak external linkage where possible

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Message-ID: <2024120748-preaching-reshape-06e9@gregkh>
Date: Sat, 7 Dec 2024 10:32:19 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: Huacai Chen <chenhuacai@...nel.org>
Cc: Huacai Chen <chenhuacai@...ngson.cn>, Sasha Levin <sashal@...nel.org>,
	Xuerui Wang <kernel@...0n.name>,
	Masahiro Yamada <masahiroy@...nel.org>,
	Nathan Chancellor <nathan@...nel.org>,
	Nick Desaulniers <ndesaulniers@...gle.com>,
	Nicolas Schier <nicolas@...sle.eu>, stable@...r.kernel.org,
	linux-kbuild@...r.kernel.org, linux-kernel@...r.kernel.org,
	loongarch@...ts.linux.dev, Ard Biesheuvel <ardb@...nel.org>
Subject: Re: [PATCH 6.1&6.6 0/3] kbuild: Avoid weak external linkage where
 possible

On Sat, Dec 07, 2024 at 05:21:00PM +0800, Huacai Chen wrote:
> Hi, Greg,
> 
> On Fri, Dec 6, 2024 at 9:04 PM Greg Kroah-Hartman
> <gregkh@...uxfoundation.org> wrote:
> >
> > On Fri, Dec 06, 2024 at 04:58:07PM +0800, Huacai Chen wrote:
> > > Backport this series to 6.1&6.6 because LoongArch gets build errors with
> > > latest binutils which has commit 599df6e2db17d1c4 ("ld, LoongArch: print
> > > error about linking without -fPIC or -fPIE flag in more detail").
> > >
> > >   CC      .vmlinux.export.o
> > >   UPD     include/generated/utsversion.h
> > >   CC      init/version-timestamp.o
> > >   LD      .tmp_vmlinux.kallsyms1
> > > loongarch64-unknown-linux-gnu-ld: kernel/kallsyms.o:(.text+0): relocation R_LARCH_PCALA_HI20 against `kallsyms_markers` can not be used when making a PIE object; recompile with -fPIE
> > > loongarch64-unknown-linux-gnu-ld: kernel/crash_core.o:(.init.text+0x984): relocation R_LARCH_PCALA_HI20 against `kallsyms_names` can not be used when making a PIE object; recompile with -fPIE
> > > loongarch64-unknown-linux-gnu-ld: kernel/bpf/btf.o:(.text+0xcc7c): relocation R_LARCH_PCALA_HI20 against `__start_BTF` can not be used when making a PIE object; recompile with -fPIE
> > > loongarch64-unknown-linux-gnu-ld: BFD (GNU Binutils) 2.43.50.20241126 assertion fail ../../bfd/elfnn-loongarch.c:2673
> > >
> > > In theory 5.10&5.15 also need this, but since LoongArch get upstream at
> > > 5.19, so I just ignore them because there is no error report about other
> > > archs now.
> >
> > Odd, why doesn't this affect other arches as well using new binutils?  I
> > hate to have to backport all of this just for one arch, as that feels
> > odd.
> The related binutils commit is only for LoongArch, so build errors
> only occured on LoongArch. I don't know why other archs have no
> problem exactly, but may be related to their CFLAGS (for example, if
> we disable CONFIG_RELOCATABLE, LoongArch also has no build errors
> because CFLAGS changes).

does LoongArch depend on that option?  What happens if it is enabled for
other arches?  Why doesn't it break them?

> On the other hand, Ard's original patches are not for LoongArch only,
> so I think backport to stable branches is also not for LoongArch only.

Maybe Ard can answer that.

thanks,

greg k-h