From b6d859b7089dd68d3186f2a088823c322ad4852e Mon Sep 17 00:00:00 2001
From: Ben Cressey <bcressey@amazon.com>
Date: Mon, 19 Apr 2021 18:46:04 +0000
Subject: [PATCH] Makefile: add prepare target for external modules

We need to ensure that native versions of programs like `objtool` are
built before trying to build out-of-tree modules, or else the build
will fail.

Unlike other distributions, we cannot include these programs in our
kernel-devel archive, because we rely on cross-compilation: these are
"host" programs and may not match the architecture of the target.

Ideally, out-of-tree builds would run `make prepare` first, so that
these programs could be compiled in the normal fashion. We ship all
the files needed for this to work. However, this requirement is
specific to our use case, and DKMS does not support it.

Adding a minimal prepare target to the dependency graph causes the
programs to be built automatically and improves compatibility with
existing solutions.

Signed-off-by: Ben Cressey <bcressey@amazon.com>
---
 Makefile | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/Makefile b/Makefile
index aba2651d0..6f0cb64df 100644
--- a/Makefile
+++ b/Makefile
@@ -1706,6 +1706,15 @@ else # KBUILD_EXTMOD
 KBUILD_BUILTIN :=
 KBUILD_MODULES := 1
 
+PHONY += modules_prepare
+modules_prepare: $(objtool_target)
+	$(Q)$(MAKE) $(build)=scripts/basic
+	$(Q)$(MAKE) $(build)=scripts/dtc
+	$(Q)$(MAKE) $(build)=scripts/mod
+	$(Q)$(MAKE) $(build)=scripts
+
+prepare: modules_prepare
+
 build-dirs := $(KBUILD_EXTMOD)
 $(MODORDER): descend
 	@:
-- 
2.39.1