From: Masahiro Yamada <masahiroy@kernel.org>
To: Jiri Slaby <jirislaby@kernel.org>
Cc: linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org,
"Nick Desaulniers" <ndesaulniers@google.com>,
"Nathan Chancellor" <nathan@kernel.org>,
"Martin Liška" <mliska@suse.cz>
Subject: Re: [PATCH v3 7/7] kbuild: remove head-y syntax
Date: Tue, 18 Oct 2022 18:12:54 +0900 [thread overview]
Message-ID: <CAK7LNARahN2xefEBb4EprpiA6B5-7Hakc1cC9_o+FieXr=a_pA@mail.gmail.com> (raw)
In-Reply-To: <1ec14007-affc-f826-6dda-f23ee166226a@kernel.org>
On Tue, Oct 18, 2022 at 5:16 PM Jiri Slaby <jirislaby@kernel.org> wrote:
>
> Hi,
>
> On 24. 09. 22, 20:19, Masahiro Yamada wrote:
> > Kbuild puts the objects listed in head-y at the head of vmlinux.
> > Conventionally, we do this for head*.S, which contains the kernel entry
> > point.
> >
> > A counter approach is to control the section order by the linker script.
> > Actually, the code marked as __HEAD goes into the ".head.text" section,
> > which is placed before the normal ".text" section.
> >
> > I do not know if both of them are needed. From the build system
> > perspective, head-y is not mandatory. If you can achieve the proper code
> > placement by the linker script only, it would be cleaner.
> >
> > I collected the current head-y objects into head-object-list.txt. It is
> > a whitelist. My hope is it will be reduced in the long run.
> >
> > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> ...
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -1149,10 +1149,10 @@ quiet_cmd_ar_vmlinux.a = AR $@
> > cmd_ar_vmlinux.a = \
> > rm -f $@; \
> > $(AR) cDPrST $@ $(KBUILD_VMLINUX_OBJS); \
> > - $(AR) mPiT $$($(AR) t $@ | head -n1) $@ $(head-y)
> > + $(AR) mPiT $$($(AR) t $@ | head -n1) $@ $$($(AR) t $@ | grep -F --file=$(srctree)/scripts/head-object-list.txt)
>
> With AR=gcc-ar, the "| head -n1" results in:
> /usr/lib64/gcc/x86_64-suse-linux/7/../../../../x86_64-suse-linux/bin/ar
> terminated with signal 13 [Broken pipe]
>
> I found out only with gcc-lto. But maybe we should make it silent in any
> case? I'm not sure how. This looks ugly (and needs the whole output to
> be piped):
> gcc-ar t vmlinux.a | ( head -n1; cat >/dev/null )
>
> Note the result appears to be correct, it's only that gcc-ar complains
> after printing out the very first line.
Indeed, I see the same message.
sed does not show such an error, though.
masahiro@zoe:~/ref/linux$ gcc-ar t vmlinux.a | head -n1
arch/x86/kernel/head_64.o
/usr/bin/ar terminated with signal 13 [Broken pipe]
masahiro@zoe:~/ref/linux$ gcc-ar t vmlinux.a | sed -n 1p
arch/x86/kernel/head_64.o
--
Best Regards
Masahiro Yamada
next prev parent reply other threads:[~2022-10-18 9:14 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-24 18:19 [PATCH v3 0/7] kbuild: various cleanups Masahiro Yamada
2022-09-24 18:19 ` [PATCH v3 1/7] kbuild: hard-code KBUILD_ALLDIRS in scripts/Makefile.package Masahiro Yamada
2022-09-28 19:09 ` Nicolas Schier
2022-09-24 18:19 ` [PATCH v3 2/7] kbuild: list sub-directories in ./Kbuild Masahiro Yamada
2022-09-24 19:37 ` kernel test robot
2022-09-24 20:27 ` kernel test robot
2022-09-25 0:28 ` Masahiro Yamada
2022-09-26 21:06 ` Nick Desaulniers
2022-09-28 8:32 ` Masahiro Yamada
2022-09-28 19:30 ` Nicolas Schier
2022-09-24 18:19 ` [PATCH v3 3/7] kbuild: move .vmlinux.objs rule to Makefile.modpost Masahiro Yamada
2022-09-28 19:35 ` Nicolas Schier
2022-09-24 18:19 ` [PATCH v3 4/7] kbuild: move vmlinux.o rule to the top Makefile Masahiro Yamada
2022-09-28 19:37 ` Nicolas Schier
2022-09-24 18:19 ` [PATCH v3 5/7] kbuild: unify two modpost invocations Masahiro Yamada
2022-09-28 19:59 ` Nicolas Schier
2022-09-28 21:05 ` Masahiro Yamada
2022-09-24 18:19 ` [PATCH v3 6/7] kbuild: use obj-y instead extra-y for objects placed at the head Masahiro Yamada
2022-09-28 20:15 ` Nicolas Schier
2022-10-24 18:24 ` Jiri Slaby
2022-10-25 12:26 ` Michael Matz
2022-10-26 8:35 ` Jiri Slaby
2022-10-26 11:20 ` Ard Biesheuvel
2022-10-26 16:29 ` Masahiro Yamada
2022-10-26 17:09 ` Michael Matz
2022-09-24 18:19 ` [PATCH v3 7/7] kbuild: remove head-y syntax Masahiro Yamada
2022-09-29 15:21 ` Nicolas Schier
2022-10-18 8:16 ` Jiri Slaby
2022-10-18 9:12 ` Masahiro Yamada [this message]
2022-09-26 21:39 ` [PATCH v3 0/7] kbuild: various cleanups Nick Desaulniers
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