From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from conuserg-07.nifty.com ([210.131.2.74]:38080 "EHLO conuserg-07.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752150AbeCNQou (ORCPT ); Wed, 14 Mar 2018 12:44:50 -0400 From: Masahiro Yamada Subject: [PATCH 7/7] kbuild: link vmlinux just once for CONFIG_TRIM_UNUSED_KSYMS Date: Thu, 15 Mar 2018 01:44:21 +0900 Message-Id: <1521045861-22418-8-git-send-email-yamada.masahiro@socionext.com> In-Reply-To: <1521045861-22418-1-git-send-email-yamada.masahiro@socionext.com> References: <1521045861-22418-1-git-send-email-yamada.masahiro@socionext.com> Sender: linux-kbuild-owner@vger.kernel.org List-ID: To: linux-kbuild@vger.kernel.org Cc: Nicolas Pitre , Jarod Wilson , Prarit Bhargava , Masahiro Yamada , Michal Marek , linux-kernel@vger.kernel.org If CONFIG_TRIM_UNUSED_KSYMS is enabled and the kernel is built from a pristine state, the vmlinux is linked twice. [1] A user runs "make" [2] First build with empty autoksyms.h [3] adjust_autoksyms.sh updates autoksyms.h and recurses "make vmlinux" --------(begin sub-make)-------- [4] Second build with new autoksyms.h [5] link-vmlinux.sh is invoked because "vmlinux" is missing ---------(end sub-make)--------- [6] link-vmlinux.sh is invoked again despite "vmlinux" is up-to-date. The reason of [6] is probably because Make already decided to update "vmlinux" at the time of [2] because "vmlinux" was missing when Make generated the dependency list. link-vmlinus.sh is costly, so it is better to not run it when unneeded. Split CONFIG_TRIM_UNUSED_KSYMS handling to a dedicated target. The reason of commit 2441e78b1919 ("kbuild: better abstract vmlinux sequential prerequisites") was to cater to CONFIG_BUILD_DOCSRC, but it was later removed by commit 184892925118 ("samples: move blackfin gptimers-example from Documentation"). I also changed adjust_autoksyms.sh to simply exit with 1 or 0 to make it look straightforward. Signed-off-by: Masahiro Yamada --- Makefile | 28 ++++++++++++---------------- scripts/adjust_autoksyms.sh | 3 +-- 2 files changed, 13 insertions(+), 18 deletions(-) diff --git a/Makefile b/Makefile index 1dab647..0a7bab6 100644 --- a/Makefile +++ b/Makefile @@ -987,21 +987,11 @@ export KBUILD_ALLDIRS := $(sort $(filter-out arch/%,$(vmlinux-alldirs)) arch Doc vmlinux-deps := $(KBUILD_LDS) $(KBUILD_VMLINUX_INIT) $(KBUILD_VMLINUX_MAIN) $(KBUILD_VMLINUX_LIBS) -# Include targets which we want to execute sequentially if the rest of the -# kernel build went well. If CONFIG_TRIM_UNUSED_KSYMS is set, this might be -# evaluated more than once. -PHONY += vmlinux_prereq -vmlinux_prereq: $(vmlinux-deps) FORCE -ifdef CONFIG_HEADERS_CHECK - $(Q)$(MAKE) -f $(srctree)/Makefile headers_check -endif -ifdef CONFIG_GDB_SCRIPTS - $(Q)ln -fsn $(abspath $(srctree)/scripts/gdb/vmlinux-gdb.py) -endif -ifdef CONFIG_TRIM_UNUSED_KSYMS - $(Q)$(CONFIG_SHELL) $(srctree)/scripts/adjust_autoksyms.sh \ - "$(MAKE) -f $(srctree)/Makefile vmlinux" -endif +# Recurse until adjust_autoksyms.sh is satisfied +PHONY += autoksyms_recursive +autoksyms_recursive: $(vmlinux-deps) + $(Q)$(CONFIG_SHELL) $(srctree)/scripts/adjust_autoksyms.sh || \ + $(MAKE) -f $(srctree)/Makefile autoksyms_recursive # For the kernel to actually contain only the needed exported symbols, # we have to build modules as well to determine what those symbols are. @@ -1023,7 +1013,13 @@ cmd_link-vmlinux = \ $(CONFIG_SHELL) $< $(LD) $(LDFLAGS) $(LDFLAGS_vmlinux) ; \ $(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true) -vmlinux: scripts/link-vmlinux.sh vmlinux_prereq $(vmlinux-deps) FORCE +vmlinux: scripts/link-vmlinux.sh autoksyms_recursive $(vmlinux-deps) FORCE +ifdef CONFIG_HEADERS_CHECK + $(Q)$(MAKE) -f $(srctree)/Makefile headers_check +endif +ifdef CONFIG_GDB_SCRIPTS + $(Q)ln -fsn $(abspath $(srctree)/scripts/gdb/vmlinux-gdb.py) +endif +$(call if_changed,link-vmlinux) # Build samples along the rest of the kernel diff --git a/scripts/adjust_autoksyms.sh b/scripts/adjust_autoksyms.sh index 7bb3618..1377cf8 100755 --- a/scripts/adjust_autoksyms.sh +++ b/scripts/adjust_autoksyms.sh @@ -95,8 +95,7 @@ if [ $changed -gt 0 ]; then info "KSYMS" "symbols: before=$old, after=$new, changed=$changed" info "UPD" "$cur_ksyms_file" mv -f "$new_ksyms_file" "$cur_ksyms_file" - # Then trigger a rebuild of affected source files - exec $@ + exit 1 else rm -f "$new_ksyms_file" fi -- 2.7.4