From: Nathan Chancellor <natechancellor@gmail.com>
To: "Maciej W. Rozycki" <macro@linux-mips.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Masahiro Yamada <masahiroy@kernel.org>,
linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
clang-built-linux@googlegroups.com, linux-kbuild@vger.kernel.org,
Nick Desaulniers <ndesaulniers@google.com>,
Fangrui Song <maskray@google.com>,
Sami Tolvanen <samitolvanen@google.com>,
Dmitry Golovin <dima@golovin.in>,
Sedat Dilek <sedat.dilek@gmail.com>
Subject: Re: [PATCH v4 4/5] MIPS: VDSO: Use $(LD) instead of $(CC) to link VDSO
Date: Sat, 2 May 2020 08:49:45 -0700 [thread overview]
Message-ID: <20200502154945.GA3361319@ubuntu-s3-xlarge-x86> (raw)
In-Reply-To: <alpine.LFD.2.21.2005021435100.3602499@eddie.linux-mips.org>
On Sat, May 02, 2020 at 02:50:34PM +0100, Maciej W. Rozycki wrote:
> On Tue, 28 Apr 2020, Nathan Chancellor wrote:
>
> > Before this patch, LD=ld.lld did nothing:
> >
> > $ llvm-readelf -p.comment arch/mips/vdso/vdso.so.dbg | sed 's/(.*//'
> > String dump of section '.comment':
> > [ 0] ClangBuiltLinux clang version 11.0.0
>
> What does it mean "did nothing", is `arch/mips/vdso/vdso.so.dbg.raw' not
> produced? Where does `arch/mips/vdso/vdso.so.dbg' come from then?
>
> Maciej
A better wording might be "Before this patch, specifying a linker like
ld.lld via the LD variable was not respected by the MIPS VDSO". I should
also probably expand on the second paragraph, maybe something like:
When clang is built in a default configuration, it first attempts to use
the target triple's default linker then the system's default linker,
which is almost always ld.bfd. To use ld.lld, '-fuse-ld=lld' must be
passed to clang. However, we do not use -fuse-ld=lld because it can be
brittle and we have support for invoking $(LD) directly because we have
separate compilation and link steps. See commit fe00e50b2db8c ("ARM:
8858/1: vdso: use $(LD) instead of $(CC) to link VDSO") and
commit 691efbedc60d2 ("arm64: vdso: use $(LD) instead of $(CC) to link
VDSO") for examples of doing this in the VDSO.
next prev parent reply other threads:[~2020-05-02 15:49 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-19 18:04 [PATCH 1/2] kbuild: add CONFIG_LD_IS_LLD Nathan Chancellor
2020-04-19 18:04 ` [PATCH 2/2] MIPS: VDSO: Do not disable VDSO when linking with ld.lld Nathan Chancellor
2020-04-19 18:17 ` Nathan Chancellor
2020-04-19 19:32 ` Masahiro Yamada
2020-04-19 20:05 ` Nathan Chancellor
2020-04-19 20:21 ` [PATCH v2 1/3] kbuild: add CONFIG_LD_IS_LLD Nathan Chancellor
2020-04-19 20:21 ` [PATCH v2 2/3] MIPS: VDSO: Move disabling the VDSO logic to Kconfig Nathan Chancellor
2020-04-20 9:53 ` Sedat Dilek
2020-04-21 2:42 ` Nathan Chancellor
2020-04-23 14:41 ` Masahiro Yamada
2020-04-19 20:21 ` [PATCH v2 3/3] MIPS: VDSO: Allow ld.lld to link the VDSO Nathan Chancellor
2020-04-23 14:38 ` [PATCH v2 1/3] kbuild: add CONFIG_LD_IS_LLD Masahiro Yamada
2020-04-23 17:18 ` [PATCH v3 1/4] " Nathan Chancellor
2020-04-23 17:18 ` [PATCH v3 2/4] MIPS: VDSO: Move disabling the VDSO logic to Kconfig Nathan Chancellor
2020-04-23 17:18 ` [PATCH v3 3/4] MIPS: VDSO: Use $(LD) instead of $(CC) to link VDSO Nathan Chancellor
2020-04-26 16:27 ` Thomas Bogendoerfer
2020-04-27 2:08 ` Nathan Chancellor
2020-04-27 16:22 ` Maciej W. Rozycki
2020-04-27 23:24 ` Nathan Chancellor
2020-04-29 17:46 ` Maciej W. Rozycki
2020-04-30 3:14 ` Nathan Chancellor
2020-04-28 2:17 ` Nathan Chancellor
2020-04-23 17:18 ` [PATCH v3 4/4] MIPS: VDSO: Allow ld.lld to link the VDSO Nathan Chancellor
2020-04-28 22:14 ` [PATCH v5 0/5] Allow ld.lld to link the MIPS VDSO Nathan Chancellor
2020-04-28 22:14 ` [PATCH v4 1/5] kbuild: add CONFIG_LD_IS_LLD Nathan Chancellor
2020-04-29 7:13 ` Sedat Dilek
2020-04-30 3:05 ` Nathan Chancellor
2020-04-28 22:14 ` [PATCH v4 2/5] MIPS: VDSO: Move disabling the VDSO logic to Kconfig Nathan Chancellor
2020-04-28 22:14 ` [PATCH v4 3/5] MIPS: Unconditionally specify '-EB' or '-EL' Nathan Chancellor
2020-04-28 22:14 ` [PATCH v4 4/5] MIPS: VDSO: Use $(LD) instead of $(CC) to link VDSO Nathan Chancellor
2020-04-28 22:54 ` Fangrui Song
2020-04-29 0:44 ` Nathan Chancellor
2020-05-02 13:34 ` Maciej W. Rozycki
2020-05-02 13:50 ` Maciej W. Rozycki
2020-05-02 15:49 ` Nathan Chancellor [this message]
2020-04-28 22:14 ` [PATCH v4 5/5] MIPS: VDSO: Allow ld.lld to link the VDSO Nathan Chancellor
2020-04-29 7:04 ` [PATCH v5 0/5] Allow ld.lld to link the MIPS VDSO Sedat Dilek
2020-04-30 3:06 ` Nathan Chancellor
2020-05-12 8:05 ` Thomas Bogendoerfer
2020-05-12 8:28 ` Nathan Chancellor
2020-05-13 11:18 ` Thomas Bogendoerfer
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