From: Nicolas Pitre <nicolas.pitre@linaro.org>
To: Michal Marek <mmarek@suse.com>
Cc: linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v7 0/8]/[PULL REQUEST] Trim unused exported kernel symbols
Date: Tue, 29 Mar 2016 16:44:34 -0400 [thread overview]
Message-ID: <1459284282-6676-1-git-send-email-nicolas.pitre@linaro.org> (raw)
This patch series provides the option to omit exported symbols from
the kernel and modules that are never referenced by any of the selected
modules in the current kernel configuration. this allows for optimizing
the compiled code and reducing final binaries' size. When using LTO the
binary size reduction is even more effective. It could also be argued
that this could bring some security advantages.
The original cover letter with lots of test results can be found here:
https://lkml.org/lkml/2016/2/8/813
Please consider for merging into your tree.
Alternately, the following branch can be pulled:
http://git.linaro.org/people/nicolas.pitre/linux.git autoksyms
Thanks.
Changes from v6:
- Rebased on v4.6-rc1, including adjustments to the recently introduced
rule_as_o_S.
- Explicitly ignored more if_changed_dep callers for which no EXPORT_SYMBOL
can be parsed.
Changes from v5:
- Disable automatic dependency file generation during the preprocessor
pass when gathering exported symbol names. Not only it is redundant
but in some conditions this crashes fixdep that might be reading the
previous dependency file at the same time. Reported by Michal Marek.
- Redirect error messages to stderr rather than pass it as a symbol name
dependency.
Changes from v4:
- Correctness changes plus small cleanup to adjust_autoksyms.sh as
suggested by Michal Marek.
- Changed ksym build dependency generation by re-running the preprocessor
rather than collecting those dependencies as warnings through stderr
which was too fragile.
Changes from v3:
- Shell portability changes to adjust_autoksyms.sh, partly from
suggestions by Zev Weiss.
- Fix sample modules by building them before adjust_autoksyms.sh is run.
Changes from v2:
- Generating the build dependencies by parsing the source with fixdep
turned out to be unreliable due to all the EXPORT_SYMBOL() variants,
and especially their use within macros where the actual symbol name
is known only after running the preprocessor. This list of symbol names
is now obtained from the preprocessor directly, fixing allmodconfig
builds.
Changes from v1:
- Replaced "exp" that doesn't convey the right meaning as noted by
Sam Ravnborg. The "ksym" identifier is actually what the kernel
already uses for this. Therefore:
- CONFIG_TRIM_UNUSED_EXPSYMS --> CONFIG_TRIM_UNUSED_KSYMS
- include/generated/expsyms.h --> include/generated/autoksyms.h
- #define __EXPSYM_* --> #define __KSYM_*
- Some sed regexp improvements as suggested by Al Viro.
- Renamed vmlinux_recursive target to autoksyms_recursive.
- Accept EXPORT_SYMBOL variants with a prefix, e.g. ACPI_EXPORT_SYMBOL.
- Minor commit log clarifications.
- Added Rusty's ACK.
diffstat:
Makefile | 23 +++++++--
include/linux/export.h | 33 ++++++++++++-
init/Kconfig | 16 ++++++
scripts/Kbuild.include | 32 +++++++++++-
scripts/Makefile.build | 32 ++++++------
scripts/adjust_autoksyms.sh | 101 ++++++++++++++++++++++++++++++++++++++
scripts/basic/fixdep.c | 61 +++++++++++++++++------
7 files changed, 261 insertions(+), 37 deletions(-)
next reply other threads:[~2016-03-29 20:45 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-29 20:44 Nicolas Pitre [this message]
2016-03-29 20:44 ` [PATCH v7 1/8] kbuild: record needed exported symbols for modules Nicolas Pitre
2016-03-29 20:44 ` [PATCH v7 2/8] export.h: allow for per-symbol configurable EXPORT_SYMBOL() Nicolas Pitre
2016-03-29 20:44 ` [PATCH v7 3/8] fixdep: accept extra dependencies on stdin Nicolas Pitre
2016-03-29 20:44 ` [PATCH v7 4/8] kbuild: de-duplicate fixdep usage Nicolas Pitre
2016-03-29 20:44 ` [PATCH v7 5/8] kbuild: add fine grained build dependencies for exported symbols Nicolas Pitre
2016-03-29 20:44 ` [PATCH v7 6/8] kbuild: create/adjust generated/autoksyms.h Nicolas Pitre
2016-03-29 20:44 ` [PATCH v7 7/8] kbuild: build sample modules along with the rest of the kernel Nicolas Pitre
2016-03-29 20:44 ` [PATCH v7 8/8] kconfig option for TRIM_UNUSED_KSYMS Nicolas Pitre
[not found] <l0Vnaswuk0zQ0l0Vpa1Uwn@videotron.ca>
2016-04-06 13:59 ` [PATCH v7 0/8]/[PULL REQUEST] Trim unused exported kernel symbols Nicolas Pitre
[not found] ` <nnzoaR8KUeMRCnnzpaKqKi@videotron.ca>
2016-04-19 3:32 ` Nicolas Pitre
2016-04-20 7:16 ` Michal Marek
2016-04-20 15:55 ` Nicolas Pitre
2016-04-20 19:26 ` Nicolas Pitre
2016-04-20 19:26 ` Nicolas Pitre
2016-04-26 8:17 ` Michal Marek
2016-04-26 15:17 ` Nicolas Pitre
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