From: Jiri Slaby <jirislaby@kernel.org>
To: Masahiro Yamada <masahiroy@kernel.org>, linux-kbuild@vger.kernel.org
Cc: 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 10:16:20 +0200 [thread overview]
Message-ID: <1ec14007-affc-f826-6dda-f23ee166226a@kernel.org> (raw)
In-Reply-To: <20220924181915.3251186-8-masahiroy@kernel.org>
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.
thanks,
--
js
suse labs
next prev parent reply other threads:[~2022-10-18 8:16 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 [this message]
2022-10-18 9:12 ` Masahiro Yamada
2022-09-26 21:39 ` [PATCH v3 0/7] kbuild: various cleanups Nick Desaulniers
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