kbuild: add workaround for Debian make-kpkg

masahir0y · masahir0y · commit 2b50f7ab6368 · 2019-03-14T02:39:12.000+09:00
Since commit 3812b8c ("kbuild: make -r/-R effective in top Makefile for old Make versions"), make-kpkg is not working. make-kpkg directly includes the top Makefile of Linux kernel, and appends some debian_* targets. /usr/share/kernel-package/ruleset/kernel_version.mk: # Include the kernel makefile override dot-config := 1 include Makefile dot-config := 1 I did not know the kernel Makefile was used in that way, and it is hard to guarantee the behavior when the kernel Makefile is included by another Makefile from a different project. It looks like Debian Stretch stopped providing make-kpkg. Maybe it is obsolete and being replaced with 'make deb-pkg' etc. but still widely used. This commit adds a workaround; if the top Makefile is included by another Makefile, skip sub-make in order to make the main part visible. 'MAKEFLAGS += -rR' does not become effective for GNU Make < 4.0, but Debian/Ubuntu is already using newer versions. The effect of this commit: Debian 8 (Jessie) : Fixed Debian 9 (Stretch) : make-kpkg (kernel-package) is not provided Ubuntu 14.04 LTS : NOT Fixed Ubuntu 16.04 LTS : Fixed Ubuntu 18.04 LTS : Fixed This commit cannot fix Ubuntu 14.04 because it installs GNU Make 3.81, but its support will end in Apr 2019, which is before the Linux v5.1 release. I added warning so that nobody would try to include the top Makefile. Fixes: 3812b8c ("kbuild: make -r/-R effective in top Makefile for old Make versions") Reported-by: Liz Zhang <lizzha@microsoft.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Tested-by: Lili Deng <v-lide@microsoft.com> Cc: Manoj Srivastava <srivasta@debian.org>
diff --git a/Makefile b/Makefile
@@ -31,6 +31,16 @@ _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
