RHEL/CentOS 7, a popular distribution that installs 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.
This follows Linux commit 5f99665ee8f4 ("kbuild: raise the minimum
GNU Make requirement to 4.0"). Raise the enforced minimum to 4.0 and
drop the now-unreachable compatibility code for older versions:
- Add an explicit "GNU Make >= 4.0 is required" version-check gate.
- Simplify the "make -s" (silent mode) detection to a single
unconditional check instead of branching on make-4 vs make-3.8x.
This also changes behaviour on Make 4.x: the old check matched only
when 's' was the last single-letter flag in MAKEFLAGS, whereas the
new check matches 's' among them, as in Linux.
- Drop the GNU Make 3.x sub-make workaround, which is now dead code.
- Document the minimum GNU Make version in doc/build/gcc.rst.
Signed-off-by: Suraj Kakade <[email protected]>
Reviewed-by: Simon Glass <[email protected]>
---
Makefile | 20 +++++---------------
doc/build/gcc.rst | 3 +++
2 files changed, 8 insertions(+), 15 deletions(-)
diff --git a/Makefile b/Makefile
index 6303a0cca6a..5abd0a7ce04 100644
--- a/Makefile
+++ b/Makefile
@@ -12,6 +12,10 @@ NAME =
# Comments in this file are targeted only to the developer, do not
# expect to learn how to build the kernel reading this file.
+ifeq ($(filter output-sync,$(.FEATURES)),)
+$(error GNU Make >= 4.0 is required. Your Make version is $(MAKE_VERSION))
+endif
+
$(if $(filter __%, $(MAKECMDGOALS)), \
$(error targets prefixed with '__' are only for internal use))
@@ -93,15 +97,9 @@ endif
# If the user is running make -s (silent mode), suppress echoing of
# commands
-ifneq ($(filter 4.%,$(MAKE_VERSION)),) # make-4
-ifneq ($(filter %s ,$(firstword x$(MAKEFLAGS))),)
- quiet=silent_
-endif
-else # make-3.8x
-ifneq ($(filter s% -s%,$(MAKEFLAGS)),)
+ifneq ($(findstring s,$(firstword -$(MAKEFLAGS))),)
quiet=silent_
endif
-endif
export quiet Q KBUILD_VERBOSE
@@ -166,14 +164,6 @@ ifneq ($(abs_srctree),$(abs_objtree))
MAKEFLAGS += --include-dir=$(abs_srctree)
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 abs_srctree abs_objtree
export sub_make_done := 1
diff --git a/doc/build/gcc.rst b/doc/build/gcc.rst
index 1fef718ceec..16afe292899 100644
--- a/doc/build/gcc.rst
+++ b/doc/build/gcc.rst
@@ -7,6 +7,9 @@ Dependencies
For building U-Boot you need a GCC compiler for your host platform. If you
are not building on the target platform you further need a GCC cross compiler.
+GNU Make 4.0 or later is required to build U-Boot. Older versions are rejected
+with an error at the start of the build.
+
Debian based
~~~~~~~~~~~~
--
2.43.7
