From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932390AbcKIAS1 (ORCPT ); Tue, 8 Nov 2016 19:18:27 -0500 Received: from mga09.intel.com ([134.134.136.24]:13126 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932212AbcKIASX (ORCPT ); Tue, 8 Nov 2016 19:18:23 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.31,612,1473145200"; d="scan'208";a="28971585" Date: Tue, 8 Nov 2016 16:18:21 -0800 From: Josh Triplett To: Andrew Morton , Kees Cook , Johannes Weiner , Arnd Bergmann , Ingo Molnar , Andy Lutomirski , Petr Mladek , Thomas Garnier , Ard Biesheuvel , Nicolas Pitre , Zefan Li , Li Bin , "Eric W. Biederman" , Dmitry Vyukov , Ralf Baechle , Alex Thorlton , Michal Hocko , Mateusz Guzik , Cyrill Gorcunov , John Stultz , Al Viro , Zach Brown , Anna Schumaker , Dave Hansen , linux-kernel@vger.kernel.org, linux-api@vger.kernel.org Subject: [PATCH 2/2] kernel: Support compiling out the prctl syscall Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20161014 (1.7.1) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Some embedded systems can do without the prctl syscall, saving some space. This also avoids regular increases in tinyconfig size as people add more non-optional functionality to prctl (observed via the 0-day kernel infrastructure). bloat-o-meter results: add/remove: 0/3 grow/shrink: 0/1 up/down: 0/-2143 (-2143) function old new delta offsets 23 12 -11 prctl_set_auxv 97 - -97 sys_prctl 794 - -794 prctl_set_mm 1241 - -1241 Total: Before=1902583, After=1900440, chg -0.11% Signed-off-by: Josh Triplett --- init/Kconfig | 12 ++++++++++++ kernel/Makefile | 3 ++- kernel/sys_ni.c | 1 + 3 files changed, 15 insertions(+), 1 deletion(-) diff --git a/init/Kconfig b/init/Kconfig index 34407f1..1dd671c 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1408,6 +1408,18 @@ config MULTIUSER If unsure, say Y here. +config PRCTL + bool "prctl syscall" if EXPERT + default y + help + This option enables the prctl syscall, used for a variety of + operations on the current process. + + If building an embedded system where no applications or libraries use + prctl, you can disable this option to save space. + + If unsure, say Y here. + config SGETMASK_SYSCALL bool "sgetmask/ssetmask syscalls support" if EXPERT def_bool PARISC || MN10300 || BLACKFIN || M68K || PPC || MIPS || X86 || SPARC || CRIS || MICROBLAZE || SUPERH diff --git a/kernel/Makefile b/kernel/Makefile index 37c6d4c..43fb4ca 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -9,9 +9,10 @@ obj-y = fork.o exec_domain.o panic.o \ extable.o params.o \ kthread.o sys_ni.o nsproxy.o \ notifier.o ksysfs.o cred.o reboot.o \ - async.o range.o smpboot.o ucount.o prctl.o + async.o range.o smpboot.o ucount.o obj-$(CONFIG_MULTIUSER) += groups.o +obj-$(CONFIG_PRCTL) += prctl.o ifdef CONFIG_FUNCTION_TRACER # Do not trace internal ftrace files diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index 635482e..84fd646 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -175,6 +175,7 @@ cond_syscall(sys_setfsgid); cond_syscall(sys_capget); cond_syscall(sys_capset); cond_syscall(sys_copy_file_range); +cond_syscall(sys_prctl); /* arch-specific weak syscall entries */ cond_syscall(sys_pciconfig_read); -- git-series 0.8.11