Re: [PATCH 2/2] Makefile: drop GNU Make < 4.0 compatibility code

Hi Suraj

On Thu, 27 Aug 2026 at 15:11, Suraj Kakade <[email protected]> wrote:
>
> 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.
>
> Raise the enforced minimum GNU Make version 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.
> - Drop the GNU Make 3.x sub-make workaround, which is now dead code.

Overall I agree on bumnping the minimum requirements to 4.0. In fact,
I think I did that when I did the Makefile bump to 5.x. However, the
macOS tools stopped compiling. We need to check the CI for that before
merging this.

>
> Fixes: ffe29ebc0701 ("kbuild: sync top Makefile with Linux 3.18-rc1")
> Fixes: 5f520875bdf0 ("kbuild: Bump the build system to 5.1")
> Signed-off-by: Suraj Kakade <[email protected]>

Why do we need fixes tags?

Cheers
/Ilias

> ---
>  Makefile | 20 +++++---------------
>  1 file changed, 5 insertions(+), 15 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index 436f384f22a..889ac7bade5 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
>
> --
> 2.43.7
>