From: "Fāng-ruì Sòng" <maskray@google.com>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: linux-kbuild@vger.kernel.org,
Nathan Chancellor <nathan@kernel.org>,
linux-kernel@vger.kernel.org,
Nick Desaulniers <ndesaulniers@google.com>,
Nicolas Pitre <nico@fluxnic.net>,
clang-built-linux@googlegroups.com
Subject: Re: [PATCH] kbuild: Fix 'no symbols' warning when CONFIG_TRIM_UNUSD_KSYMS=y
Date: Sat, 14 Aug 2021 20:18:31 -0700 [thread overview]
Message-ID: <CAFP8O3JtOpb368h4PBbYnR4fsqRYkX_TKuCKrS-Csu=dMMNiKA@mail.gmail.com> (raw)
In-Reply-To: <3afe5054-8129-fe42-b5a4-00bd091b1a0c@kernel.org>
On Sat, Aug 14, 2021 at 6:15 PM Nathan Chancellor <nathan@kernel.org> wrote:
>
> On 8/14/2021 4:41 PM, Masahiro Yamada wrote:
> > When CONFIG_TRIM_UNUSED_KSYMS is enabled, I see some warnings like this:
> >
> > nm: arch/x86/entry/vdso/vdso32/note.o: no symbols
> >
> > $NM (both GNU nm and llvm-nm) warns when no symbol is found in the
> > object. Suppress the stderr.
> >
> > Fixes: bbda5ec671d3 ("kbuild: simplify dependency generation for CONFIG_TRIM_UNUSED_KSYMS")
> > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
LGTM.
FWIW binutils>=2.37 `nm -q` can be used to suppress "no symbols"
https://sourceware.org/bugzilla/show_bug.cgi?id=27408
llvm-nm>=13.0.0 supports -q as well.
> Reviewed-by: Nathan Chancellor <nathan@kernel.org>
>
> > ---
> >
> > scripts/gen_ksymdeps.sh | 5 ++++-
> > 1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/scripts/gen_ksymdeps.sh b/scripts/gen_ksymdeps.sh
> > index 1324986e1362..5493124e8ee6 100755
> > --- a/scripts/gen_ksymdeps.sh
> > +++ b/scripts/gen_ksymdeps.sh
> > @@ -4,7 +4,10 @@
> > set -e
> >
> > # List of exported symbols
> > -ksyms=$($NM $1 | sed -n 's/.*__ksym_marker_\(.*\)/\1/p' | tr A-Z a-z)
> > +#
> > +# If the object has no symbol, $NM warns 'no symbols'.
> > +# Suppress the stdout.
> > +ksyms=$($NM $1 2>/dev/null | sed -n 's/.*__ksym_marker_\(.*\)/\1/p' | tr A-Z a-z)
> >
> > if [ -z "$ksyms" ]; then
> > exit 0
> >
>
> --
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--
宋方睿
next prev parent reply other threads:[~2021-08-15 3:18 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-14 23:41 [PATCH] kbuild: Fix 'no symbols' warning when CONFIG_TRIM_UNUSD_KSYMS=y Masahiro Yamada
2021-08-15 1:15 ` Nathan Chancellor
2021-08-15 3:18 ` Fāng-ruì Sòng [this message]
2021-08-18 4:28 ` Masahiro Yamada
2021-08-15 3:37 ` Nicolas Pitre
2021-08-18 4:28 ` Masahiro Yamada
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