From patchwork Mon Feb 29 03:48:04 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicolas Pitre X-Patchwork-Id: 63165 Delivered-To: patch@linaro.org Received: by 10.112.199.169 with SMTP id jl9csp1022279lbc; Sun, 28 Feb 2016 19:48:36 -0800 (PST) X-Received: by 10.98.16.150 with SMTP id 22mr19185861pfq.128.1456717715848; Sun, 28 Feb 2016 19:48:35 -0800 (PST) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id c10si1120327pat.170.2016.02.28.19.48.35; Sun, 28 Feb 2016 19:48:35 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755982AbcB2DsZ (ORCPT + 30 others); Sun, 28 Feb 2016 22:48:25 -0500 Received: from relais.videotron.ca ([24.201.245.36]:50379 "EHLO relais.videotron.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755154AbcB2DsV (ORCPT ); Sun, 28 Feb 2016 22:48:21 -0500 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 <0O3A00DWJIKK8920@VL-VM-MR007.ip.videotron.ca>; Sun, 28 Feb 2016 22:48:20 -0500 (EST) Received: from xanadu.home (xanadu.home [192.168.2.2]) by yoda.home (Postfix) with ESMTP id 95FBB2DA01EF; Sun, 28 Feb 2016 22:48:20 -0500 (EST) From: Nicolas Pitre To: Michal Marek Cc: linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 1/8] kbuild: record needed exported symbols for modules Date: Sun, 28 Feb 2016 22:48:04 -0500 Message-id: <1456717691-28298-2-git-send-email-nicolas.pitre@linaro.org> X-Mailer: git-send-email 2.5.0 In-reply-to: <1456717691-28298-1-git-send-email-nicolas.pitre@linaro.org> References: <1456717691-28298-1-git-send-email-nicolas.pitre@linaro.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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_KSYMS is selected. Signed-off-by: Nicolas Pitre Acked-by: Rusty Russell --- scripts/Makefile.build | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) -- 2.5.0 diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 2c47f9c305..f4b4320e0d 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 (or empty line if not enabled) +ifdef CONFIG_TRIM_UNUSED_KSYMS +cmd_undef_syms = $(NM) $@ | sed -n 's/^ \+U //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)