From d9f78edfd81b9e484423534360350ef7253cc888 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 6 Aug 2019 19:03:21 +0900 Subject: kbuild: fix false-positive need-builtin calculation The current implementation of need-builtin is false-positive, for example, in the following Makefile: obj-m := foo/ obj-y := foo/bar/ ..., where foo/built-in.a is not required. Signed-off-by: Masahiro Yamada --- scripts/Makefile.build | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'scripts/Makefile.build') diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 0d434d0afc0b..3fe0c73e002c 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -487,7 +487,8 @@ targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \ PHONY += $(subdir-ym) $(subdir-ym): - $(Q)$(MAKE) $(build)=$@ need-builtin=$(if $(findstring $@,$(subdir-obj-y)),1) + $(Q)$(MAKE) $(build)=$@ \ + need-builtin=$(if $(filter $@/built-in.a, $(subdir-obj-y)),1) # Add FORCE to the prequisites of a target to force it to be always rebuilt. # --------------------------------------------------------------------------- -- cgit v1.2.3 From 4f2c8f3089f538f556c86f26603a062865e4aa94 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 6 Aug 2019 19:03:22 +0900 Subject: kbuild: generate modules.order only in directories visited by obj-y/m The modules.order files in directories visited by the chain of obj-y or obj-m are merged to the upper-level ones, and become parts of the top-level modules.order. On the other hand, there is no need to generate modules.order in directories visited by subdir-y or subdir-m since they would become orphan anyway. Signed-off-by: Masahiro Yamada --- scripts/Makefile.build | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'scripts/Makefile.build') diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 3fe0c73e002c..37a1d2cd49d4 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -488,7 +488,8 @@ targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \ PHONY += $(subdir-ym) $(subdir-ym): $(Q)$(MAKE) $(build)=$@ \ - need-builtin=$(if $(filter $@/built-in.a, $(subdir-obj-y)),1) + need-builtin=$(if $(filter $@/built-in.a, $(subdir-obj-y)),1) \ + need-modorder=$(if $(need-modorder),$(if $(filter $@/modules.order, $(modorder)),1)) # Add FORCE to the prequisites of a target to force it to be always rebuilt. # --------------------------------------------------------------------------- -- cgit v1.2.3 From c07d8d47bca1b325102fa2be3a463075f7b051d9 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 8 Aug 2019 20:21:11 +0900 Subject: kbuild: show hint if subdir-y/m is used to visit module Makefile Since commit ff9b45c55b26 ("kbuild: modpost: read modules.order instead of $(MODVERDIR)/*.mod"), a module is no longer built in the following pattern: [Makefile] subdir-y := some-module [some-module/Makefile] obj-m := some-module.o You cannot write Makefile this way in upstream because modules.order is not correctly generated. subdir-y is used to descend to a sub-directory that builds tools, device trees, etc. For external modules, the modules order does not matter. So, the Makefile above was known to work. I believe the Makefile should be re-written as follows: [Makefile] obj-m := some-module/ [some-module/Makefile] obj-m := some-module.o However, people will have no idea if their Makefile suddenly stops working. In fact, I received questions from multiple people. Show a warning for a while if obj-m is specified in a Makefile visited by subdir-y or subdir-m. I touched the %/ rule to avoid false-positive warnings for the single target. Cc: Jan Kiszka Cc: Tom Stonecypher Signed-off-by: Masahiro Yamada Tested-by: Jan Kiszka --- scripts/Makefile.build | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'scripts/Makefile.build') diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 37a1d2cd49d4..2f66ed388d1c 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -52,6 +52,13 @@ ifndef obj $(warning kbuild: Makefile.build is included improperly) endif +ifeq ($(MAKECMDGOALS)$(need-modorder),) +ifneq ($(obj-m),) +$(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.) +$(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.) +endif +endif + # =========================================================================== ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),) -- cgit v1.2.3