From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752561AbcF1Vub (ORCPT ); Tue, 28 Jun 2016 17:50:31 -0400 Received: from smtprelay0195.hostedemail.com ([216.40.44.195]:36075 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752486AbcF1Vu3 (ORCPT ); Tue, 28 Jun 2016 17:50:29 -0400 X-Session-Marker: 6A6F6540706572636865732E636F6D X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,joe@perches.com,:::::::::::::::::::::::::::::::::::::::,RULES_HIT:41:355:379:541:599:966:973:988:989:1260:1277:1311:1313:1314:1345:1359:1373:1437:1515:1516:1518:1534:1539:1593:1594:1711:1730:1747:1777:1792:2196:2199:2393:2559:2562:2693:2828:3138:3139:3140:3141:3142:3352:3622:3865:3867:3868:3870:3871:3872:3874:4321:4385:5007:6119:6120:6742:7901:7903:10004:10400:10848:11232:11658:11914:12043:12517:12519:12740:13069:13311:13357:13439:13894:14659:14721:21080:21324:21434,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:none,Custom_rules:0:0:0,LFtime:1,LUA_SUMMARY:none X-HE-Tag: pain74_50f1076f68a56 X-Filterd-Recvd-Size: 1953 Message-ID: <1467150555.24287.77.camel@perches.com> Subject: Re: [PATCH v1 0/2] Introduce the initify gcc plugin From: Joe Perches To: Emese Revfy , kernel-hardening@lists.openwall.com, Matt Davis Cc: pageexec@freemail.hu, spender@grsecurity.net, mmarek@suse.com, keescook@chromium.org, linux-kernel@vger.kernel.org, yamada.masahiro@socionext.com, linux-kbuild@vger.kernel.org, minipli@ld-linux.so, linux@armlinux.org.uk, catalin.marinas@arm.com, linux@rasmusvillemoes.dk, david.brown@linaro.org, benh@kernel.crashing.org, tglx@linutronix.de, akpm@linux-foundation.org, jlayton@poochiereds.net, arnd@arndb.de Date: Tue, 28 Jun 2016 14:49:15 -0700 In-Reply-To: <20160628133407.10c2ea1ecd194e8085e84c5a@gmail.com> References: <20160628133407.10c2ea1ecd194e8085e84c5a@gmail.com> Content-Type: text/plain; charset="ISO-8859-1" X-Mailer: Evolution 3.18.5.2-0ubuntu3 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2016-06-28 at 13:34 +0200, Emese Revfy wrote: > I would like to introduce the initify gcc plugin. The kernel already has > a mechanism to free up code and data memory that is only used during kernel > or module initialization. > This plugin will teach the compiler to find more such code and data that > can be freed after initialization. It reduces memory usage. > The initify gcc plugin can be useful for embedded systems. Another potentially useful plugin, especially for embedded systems, would be to compress any string literal marked with  __attribute__((format(printf, string-index,))) and decompress the compressed format on the stack in lib/vsprintf.c vsnprintf just before use. I've started to experiment with that. From mboxrd@z Thu Jan 1 00:00:00 1970 Reply-To: kernel-hardening@lists.openwall.com Message-ID: <1467150555.24287.77.camel@perches.com> From: Joe Perches Date: Tue, 28 Jun 2016 14:49:15 -0700 In-Reply-To: <20160628133407.10c2ea1ecd194e8085e84c5a@gmail.com> References: <20160628133407.10c2ea1ecd194e8085e84c5a@gmail.com> Content-Type: text/plain; charset="ISO-8859-1" Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [kernel-hardening] Re: [PATCH v1 0/2] Introduce the initify gcc plugin To: Emese Revfy , kernel-hardening@lists.openwall.com, Matt Davis Cc: pageexec@freemail.hu, spender@grsecurity.net, mmarek@suse.com, keescook@chromium.org, linux-kernel@vger.kernel.org, yamada.masahiro@socionext.com, linux-kbuild@vger.kernel.org, minipli@ld-linux.so, linux@armlinux.org.uk, catalin.marinas@arm.com, linux@rasmusvillemoes.dk, david.brown@linaro.org, benh@kernel.crashing.org, tglx@linutronix.de, akpm@linux-foundation.org, jlayton@poochiereds.net, arnd@arndb.de List-ID: On Tue, 2016-06-28 at 13:34 +0200, Emese Revfy wrote: > I would like to introduce the initify gcc plugin. The kernel already has > a mechanism to free up code and data memory that is only used during kernel > or module initialization. > This plugin will teach the compiler to find more such code and data that > can be freed after initialization. It reduces memory usage. > The initify gcc plugin can be useful for embedded systems. Another potentially useful plugin, especially for embedded systems, would be to compress any string literal marked with  __attribute__((format(printf, string-index,))) and decompress the compressed format on the stack in lib/vsprintf.c vsnprintf just before use. I've started to experiment with that.