From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423083Ab2LGGOk (ORCPT ); Fri, 7 Dec 2012 01:14:40 -0500 Received: from ozlabs.org ([203.10.76.45]:57688 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752889Ab2LGGOj (ORCPT ); Fri, 7 Dec 2012 01:14:39 -0500 From: Rusty Russell To: Michal Marek , Takashi Iwai Cc: David Howells , linux-kernel@vger.kernel.org, James Hogan Subject: Re: [PATCH 2/3] MODSIGN: Avoid using .incbin in C source In-Reply-To: <20121205095057.GA26543@sepie.suse.cz> References: <1354616321-13520-2-git-send-email-mmarek@suse.cz> <1354616321-13520-1-git-send-email-mmarek@suse.cz> <22396.1354645048@warthog.procyon.org.uk> <87hao1gyiv.fsf@rustcorp.com.au> <20121205095057.GA26543@sepie.suse.cz> User-Agent: Notmuch/0.14 (http://notmuchmail.org) Emacs/23.4.1 (i686-pc-linux-gnu) Date: Fri, 07 Dec 2012 15:10:56 +1030 Message-ID: <87zk1qeap3.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Michal Marek writes: > It looks good, but looking at your patch, I just noticed that we have two > versions of the SYMBOL_PREFIX macro in the kernel now: > > scripts/Makefile.lib has had since some time > > ifdef CONFIG_SYMBOL_PREFIX > _sym_flags = -DSYMBOL_PREFIX=$(patsubst "%",%,$(CONFIG_SYMBOL_PREFIX)) > _cpp_flags += $(_sym_flags) > _a_flags += $(_sym_flags) > endif > > while include/linux/kernel.h now has > > /* This helps us to avoid #ifdef CONFIG_SYMBOL_PREFIX */ > #ifdef CONFIG_SYMBOL_PREFIX > #define SYMBOL_PREFIX CONFIG_SYMBOL_PREFIX > #else > #define SYMBOL_PREFIX "" > #endif What a mess! AFAICT there's one place which a non-string SYMBOL_PREFIX: include/asm-generic/vmlinux.lds.h So we do need it, and the only sane way seems to be via the cmdline and the shell usefully stripping quotes as we do. So I just took Takashi's do-it-all-in-asm fix, and removed this re-definition (we have the same thing, BTW, called MODULE_SYMBOL_PREFIX). I added a comment about the cmdline SYMBOL_PREFIX, too. Thanks, Rusty. From: Takashi Iwai Subject: MODSIGN: Avoid using .incbin in C source Using the asm .incbin statement in C sources breaks any gcc wrapper which assumes that preprocessed C source is self-contained. Use a separate .S file to include the siging key and certificate. [ This means we no longer need SYMBOL_PREFIX which is defined in kernel.h from cbdbf2abb7844548a7d7a6a2ae7af6b6fbcea401, so I removed it -- RR ] Tested-by: Michal Marek Signed-off-by: Takashi Iwai Signed-off-by: Rusty Russell diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 7d8dfc7..a123b13 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -701,13 +701,6 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { } #define COMPACTION_BUILD 0 #endif -/* This helps us to avoid #ifdef CONFIG_SYMBOL_PREFIX */ -#ifdef CONFIG_SYMBOL_PREFIX -#define SYMBOL_PREFIX CONFIG_SYMBOL_PREFIX -#else -#define SYMBOL_PREFIX "" -#endif - /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */ #ifdef CONFIG_FTRACE_MCOUNT_RECORD # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD diff --git a/kernel/Makefile b/kernel/Makefile index 86e3285..0bd9d43 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -54,7 +54,7 @@ obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o obj-$(CONFIG_PROVE_LOCKING) += spinlock.o obj-$(CONFIG_UID16) += uid16.o obj-$(CONFIG_MODULES) += module.o -obj-$(CONFIG_MODULE_SIG) += module_signing.o modsign_pubkey.o +obj-$(CONFIG_MODULE_SIG) += module_signing.o modsign_pubkey.o modsign_certificate.o obj-$(CONFIG_KALLSYMS) += kallsyms.o obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o obj-$(CONFIG_KEXEC) += kexec.o @@ -139,7 +139,7 @@ ifeq ($(CONFIG_MODULE_SIG),y) extra_certificates: touch $@ -kernel/modsign_pubkey.o: signing_key.x509 extra_certificates +kernel/modsign_certificate.o: signing_key.x509 extra_certificates ############################################################################### # diff --git a/kernel/modsign_certificate.S b/kernel/modsign_certificate.S new file mode 100644 index 0000000..246b4c6 --- /dev/null +++ b/kernel/modsign_certificate.S @@ -0,0 +1,19 @@ +/* SYMBOL_PREFIX defined on commandline from CONFIG_SYMBOL_PREFIX */ +#ifndef SYMBOL_PREFIX +#define ASM_SYMBOL(sym) sym +#else +#define PASTE2(x,y) x##y +#define PASTE(x,y) PASTE2(x,y) +#define ASM_SYMBOL(sym) PASTE(SYMBOL_PREFIX, sym) +#endif + +#define GLOBAL(name) \ + .globl ASM_SYMBOL(name); \ + ASM_SYMBOL(name): + + .section ".init.data","aw" + +GLOBAL(modsign_certificate_list) + .incbin "signing_key.x509" + .incbin "extra_certificates" +GLOBAL(modsign_certificate_list_end) diff --git a/kernel/modsign_pubkey.c b/kernel/modsign_pubkey.c index 767e559..045504f 100644 --- a/kernel/modsign_pubkey.c +++ b/kernel/modsign_pubkey.c @@ -20,12 +20,6 @@ struct key *modsign_keyring; extern __initdata const u8 modsign_certificate_list[]; extern __initdata const u8 modsign_certificate_list_end[]; -asm(".section .init.data,\"aw\"\n" - SYMBOL_PREFIX "modsign_certificate_list:\n" - ".incbin \"signing_key.x509\"\n" - ".incbin \"extra_certificates\"\n" - SYMBOL_PREFIX "modsign_certificate_list_end:" - ); /* * We need to make sure ccache doesn't cache the .o file as it doesn't notice