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

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Message-Id: <20231018151950.205265-4-masahiroy@kernel.org>
Date:   Thu, 19 Oct 2023 00:19:50 +0900
From:   Masahiro Yamada <masahiroy@...nel.org>
To:     linux-kbuild@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Masahiro Yamada <masahiroy@...nel.org>,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Nicolas Schier <nicolas@...sle.eu>, bpf@...r.kernel.org
Subject: [bpf-next PATCH v2 4/4] kbuild: refactor module BTF rule

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@...nel.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