kbuild: fix building with redirected output.
Jan Altenberg <jan.altenberg@linutronix.de> reported that
building with redirected input like this failed:
make O=dir oldconfig bzImage < /dev/null
The problem were caused by a make silentoldconfig being
run before oldconfig and with a non-recent .config the build
failed because silentoldconfig requires non-redirected stdin.
Silentoldconfig was run as a side-effect of having the
top-level Makefile re-made by make.
Introducing an empty rule for the top-level Makefile
(and Kbuild.include) fixed the issue.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
diff --git a/Makefile b/Makefile
index 92dc3cb..a5252f4 100644
--- a/Makefile
+++ b/Makefile
@@ -108,6 +108,9 @@
PHONY := _all
_all:
+# Cancel implicit rules on top Makefile
+$(CURDIR)/Makefile Makefile: ;
+
ifneq ($(KBUILD_OUTPUT),)
# Invoke a second make in the output directory, passing relevant variables
# check that the output directory actually exists
@@ -121,7 +124,7 @@
PHONY += $(MAKECMDGOALS) sub-make
-$(filter-out _all sub-make,$(MAKECMDGOALS)) _all: sub-make
+$(filter-out _all sub-make $(CURDIR)/Makefile, $(MAKECMDGOALS)) _all: sub-make
$(Q)@:
sub-make: FORCE
@@ -291,7 +294,8 @@
# Look for make include files relative to root of kernel src
MAKEFLAGS += --include-dir=$(srctree)
-# We need some generic definitions.
+# We need some generic definitions (do not try to remake the file).
+$(srctree)/scripts/Kbuild.include: ;
include $(srctree)/scripts/Kbuild.include
# Make variables (CC, etc...)
@@ -1560,9 +1564,6 @@
PHONY += FORCE
FORCE:
-# Cancel implicit rules on top Makefile, `-rR' will apply to sub-makes.
-Makefile: ;
-
# Declare the contents of the .PHONY variable as phony. We keep that
# information in a variable se we can use it in if_changed and friends.
.PHONY: $(PHONY)
