From a75bb4eb9e565b9f5115e2e8c07377ce32cbe69a Mon Sep 17 00:00:00 2001 From: Matthias Kaehlcke Date: Mon, 18 Mar 2019 17:10:05 -0400 Subject: Revert "kbuild: use -Oz instead of -Os when using clang" The clang option -Oz enables *aggressive* optimization for size, which doesn't necessarily result in smaller images, but can have negative impact on performance. Switch back to the less aggressive -Os. This reverts commit 6748cb3c299de1ffbe56733647b01dbcc398c419. Suggested-by: Peter Zijlstra Signed-off-by: Matthias Kaehlcke Reviewed-by: Nick Desaulniers Signed-off-by: Masahiro Yamada --- Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 99c0530489ef..8c6acfdfe660 100644 --- a/Makefile +++ b/Makefile @@ -677,7 +677,7 @@ KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow) KBUILD_CFLAGS += $(call cc-disable-warning, int-in-bool-context) ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE -KBUILD_CFLAGS += $(call cc-option,-Oz,-Os) +KBUILD_CFLAGS += -Os else KBUILD_CFLAGS += -O2 endif -- cgit From 688931a5ad4e55ba0c215248ba510cd67bc3afb4 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 19 Mar 2019 13:02:36 +0900 Subject: kbuild: skip sub-make for in-tree build with GNU Make 4.x Commit 2b50f7ab6368 ("kbuild: add workaround for Debian make-kpkg") annoyed people who want to wrap the top Makefile with GNUmakefile to customize it for their use. On second thought, we do not need to run the sub-make for in-tree build with Make 4.x because the 'MAKEFLAGS += -rR' issue only happens on GNU Make 3.x. With this commit, people will get back their workflow, and the Debian make-kpkg will still work. Fixes: 2b50f7ab6368 ("kbuild: add workaround for Debian make-kpkg") Reported-by: Andreas Schwab Reported-by: David Howells Signed-off-by: Masahiro Yamada Tested-by: Andreas Schwab Tested-by: David Howells --- Makefile | 32 ++++++++++++++++---------------- 1 file changed, 16 insertions(+), 16 deletions(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 8c6acfdfe660..6c0635f69982 100644 --- a/Makefile +++ b/Makefile @@ -31,26 +31,12 @@ _all: # descending is started. They are now explicitly listed as the # prepare rule. -# Ugly workaround for Debian make-kpkg: -# make-kpkg directly includes the top Makefile of Linux kernel. In such a case, -# skip sub-make to support debian_* targets in ruleset/kernel_version.mk, but -# displays warning to discourage such abusage. -ifneq ($(word 2, $(MAKEFILE_LIST)),) -$(warning Do not include top Makefile of Linux Kernel) -sub-make-done := 1 -MAKEFLAGS += -rR -endif - ifneq ($(sub-make-done),1) # Do not use make's built-in rules and variables # (this increases performance and avoids hard-to-debug behaviour) MAKEFLAGS += -rR -# 'MAKEFLAGS += -rR' does not become immediately effective for old -# GNU Make versions. Cancel implicit rules for this Makefile. -$(lastword $(MAKEFILE_LIST)): ; - # Avoid funny character set dependencies unexport LC_ALL LC_COLLATE=C @@ -153,6 +139,7 @@ $(if $(KBUILD_OUTPUT),, \ # 'sub-make' below. MAKEFLAGS += --include-dir=$(CURDIR) +need-sub-make := 1 else # Do not print "Entering directory ..." at all for in-tree build. @@ -160,6 +147,16 @@ MAKEFLAGS += --no-print-directory endif # ifneq ($(KBUILD_OUTPUT),) +ifneq ($(filter 3.%,$(MAKE_VERSION)),) +# 'MAKEFLAGS += -rR' does not immediately become effective for GNU Make 3.x +# We need to invoke sub-make to avoid implicit rules in the top Makefile. +need-sub-make := 1 +# Cancel implicit rules for this Makefile. +$(lastword $(MAKEFILE_LIST)): ; +endif + +ifeq ($(need-sub-make),1) + PHONY += $(MAKECMDGOALS) sub-make $(filter-out _all sub-make $(CURDIR)/Makefile, $(MAKECMDGOALS)) _all: sub-make @@ -171,8 +168,11 @@ sub-make: $(if $(KBUILD_OUTPUT),-C $(KBUILD_OUTPUT) KBUILD_SRC=$(CURDIR)) \ -f $(CURDIR)/Makefile $(filter-out _all sub-make,$(MAKECMDGOALS)) -else # sub-make-done +endif # need-sub-make +endif # sub-make-done + # We process the rest of the Makefile if this is the final invocation of make +ifeq ($(need-sub-make),) # Do not print "Entering directory ...", # but we want to display it when entering to the output directory @@ -1757,7 +1757,7 @@ existing-targets := $(wildcard $(sort $(targets))) endif # ifeq ($(config-targets),1) endif # ifeq ($(mixed-targets),1) -endif # sub-make-done +endif # need-sub-make PHONY += FORCE FORCE: -- cgit From 221cc2d27ddc49b3e06d4637db02bf78e70c573c Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 26 Mar 2019 13:02:19 +0900 Subject: kbuild: skip parsing pre sub-make code for recursion When Make recurses to the top Makefile with sub-make-done unset, the code block surrounded by 'ifneq ($(sub-make-done),1) ... endif' is parsed multiple times. This happens for in-tree building of include/config/auto.conf, *-pkg, etc. with GNU Make 4.x. This is a slight regression by commit 688931a5ad4e ("kbuild: skip sub-make for in-tree build with GNU Make 4.x") in terms of performance since that code block contains one $(shell ...) invocation. Fix it by exporting the variable irrespective of sub-make being run. I renamed it because GNU Make cannot properly export variables containing hyphens. This is probably a bug of GNU Make, and the issue in Kbuild had already been reported by commit 2bfbe7881ee0 ("kbuild: Do not use hyphen in exported variable name"). Signed-off-by: Masahiro Yamada --- Makefile | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 6c0635f69982..3c788a65d652 100644 --- a/Makefile +++ b/Makefile @@ -31,7 +31,7 @@ _all: # descending is started. They are now explicitly listed as the # prepare rule. -ifneq ($(sub-make-done),1) +ifneq ($(sub_make_done),1) # Do not use make's built-in rules and variables # (this increases performance and avoids hard-to-debug behaviour) @@ -155,6 +155,8 @@ need-sub-make := 1 $(lastword $(MAKEFILE_LIST)): ; endif +export sub_make_done := 1 + ifeq ($(need-sub-make),1) PHONY += $(MAKECMDGOALS) sub-make @@ -164,12 +166,12 @@ $(filter-out _all sub-make $(CURDIR)/Makefile, $(MAKECMDGOALS)) _all: sub-make # Invoke a second make in the output directory, passing relevant variables sub-make: - $(Q)$(MAKE) sub-make-done=1 \ + $(Q)$(MAKE) \ $(if $(KBUILD_OUTPUT),-C $(KBUILD_OUTPUT) KBUILD_SRC=$(CURDIR)) \ -f $(CURDIR)/Makefile $(filter-out _all sub-make,$(MAKECMDGOALS)) endif # need-sub-make -endif # sub-make-done +endif # sub_make_done # We process the rest of the Makefile if this is the final invocation of make ifeq ($(need-sub-make),) -- cgit From 156e7cbb3ef50d6d58b7975d79802e4ffb024dc2 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 26 Mar 2019 13:26:58 +0900 Subject: kbuild: do not overwrite .gitignore in output directory Commit 3a51ff344204 ("kbuild: gitignore output directory") seemed to bother people who version-control output directories. Andre Przywara says: "Unfortunately this breaks my setup, because I keep a totally separate git repository in my build directories to track (various versions of) .config. So .gitignore there is carefully crafted to ignore most build artefacts, but not .config, for instance." Link: https://lkml.org/lkml/2019/3/22/1819 Reported-by: Andre Przywara Signed-off-by: Masahiro Yamada Tested-by: Andre Przywara Reviewed-by: Andre Przywara --- Makefile | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 3c788a65d652..2810425541f4 100644 --- a/Makefile +++ b/Makefile @@ -499,7 +499,8 @@ outputmakefile: ifneq ($(KBUILD_SRC),) $(Q)ln -fsn $(srctree) source $(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkmakefile $(srctree) - $(Q){ echo "# this is build directory, ignore it"; echo "*"; } > .gitignore + $(Q)test -e .gitignore || \ + { echo "# this is build directory, ignore it"; echo "*"; } > .gitignore endif ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep clang),) -- cgit