When Kbuild starts building in a separate output directory, it generates
a wrapper Makefile, allowing you to invoke 'make' from the output
directory.
This commit makes it more convenient, so you can invoke 'make' without
M= or MO=.
First, you need to build external modules in a separate directory:
$ make M=/path/to/module/source/dir MO=/path/to/module/build/dir
Once the wrapper Makefile is generated in /path/to/module/build/dir,
you can proceed as follows:
$ cd /path/to/module/build/dir
$ make
Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Reviewed-by: Nicolas Schier <nicolas@xxxxxxxxx>
---
Changes in v2:
- use $(srcroot) instead of $(_vpath)
Makefile | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/Makefile b/Makefile
index 35e34cce4942..df002595341a 100644
--- a/Makefile
+++ b/Makefile
@@ -642,10 +642,20 @@ ifdef building_out_of_srctree
# At the same time when output Makefile generated, generate .gitignore to
# ignore whole output directory
+ifdef KBUILD_EXTMOD
+print_env_for_makefile = \
+ echo "export KBUILD_OUTPUT = $(objtree)"; \
+ echo "export KBUILD_EXTMOD = $(realpath $(srcroot))" ; \
+ echo "export KBUILD_EXTMOD_OUTPUT = $(CURDIR)"
+else
+print_env_for_makefile = \
+ echo "export KBUILD_OUTPUT = $(CURDIR)"
+endif
+
quiet_cmd_makefile = GEN Makefile
cmd_makefile = { \
echo "\# Automatically generated by $(abs_srctree)/Makefile: don't edit"; \
- echo "export KBUILD_OUTPUT = $(CURDIR)"; \
+ $(print_env_for_makefile); \
echo "include $(abs_srctree)/Makefile"; \
} > Makefile
--
2.43.0
