kbuild: revive single target %.ko
I removed the single target %.ko in commit ff9b45c55b26 ("kbuild:
modpost: read modules.order instead of $(MODVERDIR)/*.mod") because
the modpost stage does not work reliably. For instance, the module
dependency, modversion, etc. do not work if we lack symbol information
from the other modules.
Yet, some people still want to build only one module in their interest,
and it may be still useful if it is used within those limitations.
Fixes: ff9b45c55b26 ("kbuild: modpost: read modules.order instead of $(MODVERDIR)/*.mod")
Reported-by: Don Brace <don.brace@microsemi.com>
Reported-by: Arend Van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/Makefile b/Makefile
index 23cdf1f..d1f35e3 100644
--- a/Makefile
+++ b/Makefile
@@ -1002,6 +1002,8 @@
PHONY += prepare0
+export MODORDER := $(if $(KBUILD_EXTMOD),$(KBUILD_EXTMOD)/)modules.order
+
ifeq ($(KBUILD_EXTMOD),)
core-y += kernel/ certs/ mm/ fs/ ipc/ security/ crypto/ block/
@@ -1771,6 +1773,15 @@
$(Q)$(MAKE) $(build)=$(build-dir) $(build-target)
%.symtypes: prepare FORCE
$(Q)$(MAKE) $(build)=$(build-dir) $(build-target)
+ifeq ($(KBUILD_EXTMOD),)
+# For the single build of an in-tree module, use a temporary file to avoid
+# the situation of modules_install installing an invalid modules.order.
+%.ko: MODORDER := .modules.tmp
+endif
+%.ko: prepare FORCE
+ $(Q)$(MAKE) $(build)=$(build-dir) $(build-target:.ko=.mod)
+ $(Q)echo $(build-target) > $(MODORDER)
+ $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
# Modules
PHONY += /