From patchwork Mon Feb 8 20:28:30 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicolas Pitre X-Patchwork-Id: 8254511 Return-Path: X-Original-To: patchwork-linux-kbuild@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id CB763BEEE5 for ; Mon, 8 Feb 2016 20:44:20 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id DD9C42014A for ; Mon, 8 Feb 2016 20:44:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EFDD22026C for ; Mon, 8 Feb 2016 20:44:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755926AbcBHUnr (ORCPT ); Mon, 8 Feb 2016 15:43:47 -0500 Received: from relais.videotron.ca ([24.201.245.36]:61124 "EHLO relais.videotron.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755478AbcBHUnl (ORCPT ); Mon, 8 Feb 2016 15:43:41 -0500 X-Greylist: delayed 900 seconds by postgrey-1.27 at vger.kernel.org; Mon, 08 Feb 2016 15:43:40 EST Content-transfer-encoding: 7BIT Received: from yoda.home ([96.23.157.65]) by VL-VM-MR007.ip.videotron.ca (Oracle Communications Messaging Exchange Server 7u4-22.01 64bit (built Apr 21 2011)) with ESMTP id <0O280039TWVRSC90@VL-VM-MR007.ip.videotron.ca>; Mon, 08 Feb 2016 15:28:39 -0500 (EST) Received: from xanadu.home (xanadu.home [192.168.2.2]) by yoda.home (Postfix) with ESMTP id 8AC8C2DA053D; Mon, 08 Feb 2016 15:28:39 -0500 (EST) From: Nicolas Pitre To: Michal Marek , linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Al Viro , Rusty Russell Subject: [PATCH 1/6] kbuild: record needed exported symbols for modules Date: Mon, 08 Feb 2016 15:28:30 -0500 Message-id: <1454963315-20468-2-git-send-email-nicolas.pitre@linaro.org> X-Mailer: git-send-email 2.5.0 In-reply-to: <1454963315-20468-1-git-send-email-nicolas.pitre@linaro.org> References: <1454963315-20468-1-git-send-email-nicolas.pitre@linaro.org> Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org X-Spam-Status: No, score=-7.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Kernel modules are partially linked object files with some undefined symbols that are expected to be matched with EXPORT_SYMBOL() entries from elsewhere. Each .tmp_versions/*.mod file currently contains two line of text separated by a newline character. The first line has the actual module file name while the second line has a list of object files constituting that module. Those files are parsed by modpost (scripts/mod/sumversion.c), scripts/Makefile.modpost, scripts/Makefile.modsign, etc. Only the modpost utility cares about the second line while the others retrieve only the first line. Therefore we can add a third line to record the list of undefined symbols aka required EXPORT_SYMBOL() entries for each module into that file without breaking anything. Like for the second line, symbols are separated by a blank and the list is terminated with a newline character. To avoid needless build overhead, the undefined symbols extraction is performed only when CONFIG_TRIM_UNUSED_EXPSYMS is selected. Signed-off-by: Nicolas Pitre --- scripts/Makefile.build | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 2c47f9c305..1d8b07ea3e 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -253,6 +253,13 @@ define rule_cc_o_c mv -f $(dot-target).tmp $(dot-target).cmd endef +# List module undefined symbols +ifdef CONFIG_TRIM_UNUSED_EXPSYMS +cmd_undef_syms = $(NM) $@ | sed -n 's/^ \+U \(.*\)/\1/p' | xargs echo +else +cmd_undef_syms = echo +endif + # Built-in and composite module parts $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE $(call cmd,force_checksrc) @@ -263,7 +270,8 @@ $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE $(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE $(call cmd,force_checksrc) $(call if_changed_rule,cc_o_c) - @{ echo $(@:.o=.ko); echo $@; } > $(MODVERDIR)/$(@F:.o=.mod) + @{ echo $(@:.o=.ko); echo $@; \ + $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod) quiet_cmd_cc_lst_c = MKLST $@ cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ @@ -393,7 +401,8 @@ $(call multi_depend, $(multi-used-y), .o, -objs -y) $(multi-used-m): FORCE $(call if_changed,link_multi-m) - @{ echo $(@:.o=.ko); echo $(link_multi_deps); } > $(MODVERDIR)/$(@F:.o=.mod) + @{ echo $(@:.o=.ko); echo $(link_multi_deps); \ + $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod) $(call multi_depend, $(multi-used-m), .o, -objs -y -m) targets += $(multi-used-y) $(multi-used-m)