[bpf-next PATCH v2 4/4] kbuild: refactor module BTF rule

Masahiro Yamada
2023-10-18T15:20:25Z

newer_prereqs_except and if_changed_except are ugly hacks of the
newer-prereqs and if_changed in scripts/Kbuild.include.

Remove.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

Changes in v2:
- Fix if_changed_except to if_changed

scripts/Makefile.modfinal | 25 ++++++-------------------
1 file changed, 6 insertions(+), 19 deletions(-)

diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal
index 9fd7a26e4fe9..fc07854bb7b9 100644
--- a/scripts/Makefile.modfinal
+++ b/scripts/Makefile.modfinal
@@ -19,6 +19,9 @@ vmlinux :=
ifdef CONFIG_DEBUG_INFO_BTF_MODULES
ifneq ($(wildcard vmlinux),)
vmlinux := vmlinux
+cmd_btf = ; \
+ LLVM_OBJCOPY="$(OBJCOPY)" $(PAHOLE) -J $(PAHOLE_FLAGS) --btf_base vmlinux $@; \
+ $(RESOLVE_BTFIDS) -b vmlinux $@
else
$(warning Skipping BTF generation due to unavailability of vmlinux)
endif
@@ -41,27 +44,11 @@ quiet_cmd_ld_ko_o = LD [M] $@
cmd_ld_ko_o += \
$(LD) -r $(KBUILD_LDFLAGS) \
$(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \
- -T scripts/module.lds -o $@ $(filter %.o, $^)
+ -T scripts/module.lds -o $@ $(filter %.o, $^) \
+ $(cmd_btf)

-quiet_cmd_btf_ko = BTF [M] $@
- cmd_btf_ko = \
- LLVM_OBJCOPY="$(OBJCOPY)" $(PAHOLE) -J $(PAHOLE_FLAGS) --btf_base vmlinux $@; \
- $(RESOLVE_BTFIDS) -b vmlinux $@
-
-# Same as newer-prereqs, but allows to exclude specified extra dependencies
-newer_prereqs_except = $(filter-out $(PHONY) $(1),$?)
-
-# Same as if_changed, but allows to exclude specified extra dependencies
-if_changed_except = $(if $(call newer_prereqs_except,$(2))$(cmd-check), \
- $(cmd); \
- printf '%s\n' 'savedcmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:)
-
-# Re-generate module BTFs if either module's .ko or vmlinux changed
%.ko: %.o %.mod.o scripts/module.lds $(vmlinux) FORCE
- +$(call if_changed_except,ld_ko_o,vmlinux)
-ifdef vmlinux
- +$(if $(newer-prereqs),$(call cmd,btf_ko))
-endif
+ +$(call if_changed,ld_ko_o)

targets += $(modules:%.o=%.ko) $(modules:%.o=%.mod.o)

--
2.40.1