Commit 688931a5 authored by Masahiro Yamada's avatar Masahiro Yamada
Browse files

kbuild: skip sub-make for in-tree build with GNU Make 4.x 



Commit 2b50f7ab ("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: 2b50f7ab ("kbuild: add workaround for Debian make-kpkg")
Reported-by: default avatarAndreas Schwab <schwab@suse.de>
Reported-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: default avatarAndreas Schwab <schwab@suse.de>
Tested-by: default avatarDavid Howells <dhowells@redhat.com>
parent a75bb4eb

Makefile

+16 −16
Original line number Diff line number Diff line
@@ -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:

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