[PATCH 6/7] kbuild: make *.mod not depend on *.o

From: Masahiro Yamada
Date: Wed Apr 06 2022 - 13:28:13 EST


The dependency

$(obj)/%.mod: $(obj)/%$(mod-prelink-ext).o

... exists because *.mod files previously contained undefined symbols,
which are computed from *.o files when CONFIG_TRIM_UNUSED_KSYMS=y.

Now that the undefined symbols are put into separate *.usyms files,
there is no reason to make *.mod depend on *.o files.

Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
---

Makefile | 3 ++-
scripts/Makefile.build | 5 ++---
2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/Makefile b/Makefile
index 82ee893909e9..e915aacd02b0 100644
--- a/Makefile
+++ b/Makefile
@@ -1792,7 +1792,8 @@ ifdef single-build

# .ko is special because modpost is needed
single-ko := $(sort $(filter %.ko, $(MAKECMDGOALS)))
-single-no-ko := $(sort $(patsubst %.ko,%.mod, $(MAKECMDGOALS)))
+single-no-ko := $(filter-out $(single-ko), $(MAKECMDGOALS)) \
+ $(foreach x, o mod, $(patsubst %.ko, %.$x, $(single-ko)))

$(single-ko): single_modpost
@:
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index f7a30f378e20..3da731cf6978 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -85,7 +85,7 @@ ifdef need-builtin
targets-for-builtin += $(obj)/built-in.a
endif

-targets-for-modules := $(foreach x, mod $(if $(CONFIG_TRIM_UNUSED_KSYMS), usyms), \
+targets-for-modules := $(foreach x, o mod $(if $(CONFIG_TRIM_UNUSED_KSYMS), usyms), \
$(patsubst %.o, %.$x, $(filter %.o, $(obj-m))))

ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),)
@@ -306,7 +306,7 @@ endif
cmd_mod = echo $(addprefix $(obj)/, $(call real-search, $*.o, .o, -objs -y -m)) | \
$(AWK) -v RS='( |\n)' '!x[$$0]++' > $@

-$(obj)/%.mod: $(obj)/%$(mod-prelink-ext).o FORCE
+$(obj)/%.mod: FORCE
$(call if_changed,mod)

# List module undefined symbols
@@ -469,7 +469,6 @@ $(multi-obj-m): FORCE
$(call if_changed,link_multi-m)
$(call multi_depend, $(multi-obj-m), .o, -objs -y -m)

-targets += $(multi-obj-m)
targets := $(filter-out $(PHONY), $(targets))

# Add intermediate targets:
--
2.32.0