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Message-ID: <20190716195957.GA38495@archlinux-threadripper>
Date: Tue, 16 Jul 2019 12:59:57 -0700
From: Nathan Chancellor <natechancellor@...il.com>
To: Thomas Gleixner <tglx@...utronix.de>
Cc: LKML <linux-kernel@...r.kernel.org>,
Linus Torvalds <torvalds@...ux-foundation.org>, x86@...nel.org,
"H.J. Lu" <hjl.tools@...il.com>,
Masahiro Yamada <yamada.masahiro@...ionext.com>,
linux-kbuild@...r.kernel.org, "Theodore Y. Ts'o" <tytso@....edu>,
Mike Lothian <mike@...eburn.co.uk>
Subject: Re: [PATCH v2] kbuild: Fail if gold linker is detected
On Tue, Jul 16, 2019 at 09:47:27PM +0200, Thomas Gleixner wrote:
> The gold linker has known issues of failing the build both in random and in
> predictible ways:
>
> - The x86/X32 VDSO build fails with:
>
> arch/x86/entry/vdso/vclock_gettime-x32.o:vclock_gettime.c:function do_hres:
> error: relocation overflow: reference to 'hvclock_page'
>
> That's a known issue for years and the usual workaround is to disable
> CONFIG_X86_32
>
> - A recent build failure is caused by turning a relocation into an
> absolute one for unknown reasons. See link below.
>
> - There are a couple of gold workarounds applied already, but reports
> about broken builds with ld.gold keep coming in on a regular base and in
> most cases the root cause is unclear.
>
> In context of the most recent fail H.J. stated:
>
> "Since building a workable kernel for different kernel configurations
> isn't a requirement for gold, I don't recommend gold for kernel."
>
> So instead of dealing with attempts to duct tape gold support without
> understanding the root cause and without support from the gold folks, fail
> the build when gold is detected.
>
> Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
> Acked-by: Peter Zijlstra (Intel) <peterz@...radead.org>
> Link: https://lore.kernel.org/r/CAMe9rOqMqkQ0LNpm25yE_Yt0FKp05WmHOrwc0aRDb53miFKM+w@mail.gmail.com
Based on the crude little testing script I wrote below:
Reviewed-by: Nathan Chancellor <natechancellor@...il.com>
Tested-by: Nathan Chancellor <natechancellor@...il.com>
$ cat test.sh
#!/bin/bash
# ld.bfd (expected to pass)
make distclean defconfig || exit ${?}
# ld.gold explicitly (expected to fail)
make LD=ld.gold distclean defconfig && exit ${?}
# ld.gold as if it were the system linker (expected to fail)
ln -fs /usr/bin/ld.gold ld
PATH=${PWD}:${PATH} make distclean defconfig && exit ${?}
# ld.lld (expected to pass)
make LD=ld.lld distclean defconfig || exit ${?}
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