kbuild: raise the minimum GNU Make requirement to 4.0

RHEL/CentOS 7, popular distributions that install GNU Make 3.82, reached EOM/EOL on June 30, 2024. While you may get extended support, it is a good time to raise the minimum GNU Make version. The new requirement, GNU Make 4.0, was released in October, 2013. I did not touch the Makefiles under tools/ because I do not know the requirements for building tools. I do not find any GNU Make version checks under tools/.

Masahiro Yamada committed 2 years ago

Commit 5f996651 parent 712aba53 files · +6 −22Browse files

Unified · Split

3 files

Documentation/process/changes.rst +2 −2
Makefile +3 −19
scripts/Kbuild.include +1 −1

Documentation/process/changes.rst+2−2

@@ -33,7 +33,7 @@ GNU C 5.1 gcc --version · 32 unmodified lines
33	Clang/LLVM (optional) 13.0.1 clang --version	33	Clang/LLVM (optional) 13.0.1 clang --version
34	Rust (optional) 1.78.0 rustc --version	34	Rust (optional) 1.78.0 rustc --version
35	bindgen (optional) 0.65.1 bindgen --version	35	bindgen (optional) 0.65.1 bindgen --version
36	GNU make 3.82 make --version	36	GNU make 4.0 make --version
37	bash 4.2 bash --version	37	bash 4.2 bash --version
38	binutils 2.25 ld -v	38	binutils 2.25 ld -v
39	flex 2.5.35 flex --version	39	flex 2.5.35 flex --version
@@ -111,7 +111,7 @@ It depends on ``libclang``. · 71 unmodified lines
111	Make	111	Make
112	----	112	----
113		113
114	You will need GNU make 3.82 or later to build the kernel.	114	You will need GNU make 4.0 or later to build the kernel.
115		115
116	Bash	116	Bash
117	----	117	----

Makefile+3−19

 # Comments in this file are targeted only to the developer, do not
 # expect to learn how to build the kernel reading this file.
-ifeq ($(filter undefine,$(.FEATURES)),)
+ifeq ($(filter output-sync,$(.FEATURES)),)
-$(error GNU Make >= 3.82 is required. Your Make version is $(MAKE_VERSION))
+$(error GNU Make >= 4.0 is required. Your Make version is $(MAKE_VERSION))
 endif
 $(if $(filter __%, $(MAKECMDGOALS)), \
 # If the user is running make -s (silent mode), suppress echoing of
 # commands
-# make-4.0 (and later) keep single letter options in the 1st word of MAKEFLAGS.
+ifneq ($(findstring s,$(firstword -$(MAKEFLAGS))),)
-ifeq ($(filter 3.%,$(MAKE_VERSION)),)
-short-opts := $(firstword -$(MAKEFLAGS))
-else
-short-opts := $(filter-out --%,$(MAKEFLAGS))
-endif
-ifneq ($(findstring s,$(short-opts)),)
 quiet=silent_
 override KBUILD_VERBOSE :=
 endif
 $(error source directory cannot contain spaces or colons)
 endif
-ifneq ($(filter 3.%,$(MAKE_VERSION)),)
-# 'MAKEFLAGS += -rR' does not immediately become effective for GNU Make 3.x
-# We need to invoke sub-make to avoid implicit rules in the top Makefile.
-need-sub-make := 1
-# Cancel implicit rules for this Makefile.
-$(this-makefile): ;
-endif
 export sub_make_done := 1
 endif # sub_make_done

scripts/Kbuild.include+1−1

@@ -68,7 +68,7 @@ kbuild-file = $(or $(wildcard $(src)/Kbuild),$(src)/Makefile) · 67 unmodified lines
68	# Read a file, replacing newlines with spaces	68	# Read a file, replacing newlines with spaces
69	#	69	#
70	# Make 4.2 or later can read a file by using its builtin function.	70	# Make 4.2 or later can read a file by using its builtin function.
71	ifneq ($(filter-out 3.% 4.0 4.1, $(MAKE_VERSION)),)	71	ifneq ($(filter-out 4.0 4.1, $(MAKE_VERSION)),)
72	read-file = $(subst $(newline),$(space),$(file < $1))	72	read-file = $(subst $(newline),$(space),$(file < $1))
73	else	73	else
74	read-file = $(shell cat $1 2>/dev/null)	74	read-file = $(shell cat $1 2>/dev/null)