[PATCH 2/3] kbuild: enable objtool for *.mod.o and additional kernel objects

From: Masahiro Yamada
Date: Wed Nov 13 2024 - 18:46:22 EST


Currently, objtool is disabled in scripts/Makefile.{modfinal,vmlinux}.

This commit moves rule_cc_o_c and rule_as_o_S to scripts/Makefile.lib
and set objtool-enabled to y there.

With this change, *.mod.o, .module-common.o, builtin-dtb.o, and
vmlinux.export.o will now be covered by objtool.

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

scripts/Makefile.build | 17 -----------------
scripts/Makefile.lib | 19 +++++++++++++++++++
scripts/Makefile.modfinal | 4 ++--
scripts/Makefile.vmlinux | 4 ++--
4 files changed, 23 insertions(+), 21 deletions(-)

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 24e10c821461..18b76947fe96 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -202,23 +202,6 @@ ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),)
cmd_warn_shared_object = $(if $(word 2, $(modname-multi)),$(warning $(kbuild-file): $*.o is added to multiple modules: $(modname-multi)))
endif

-define rule_cc_o_c
- $(call cmd_and_fixdep,cc_o_c)
- $(call cmd,checksrc)
- $(call cmd,checkdoc)
- $(call cmd,gen_objtooldep)
- $(call cmd,gen_symversions_c)
- $(call cmd,record_mcount)
- $(call cmd,warn_shared_object)
-endef
-
-define rule_as_o_S
- $(call cmd_and_fixdep,as_o_S)
- $(call cmd,gen_objtooldep)
- $(call cmd,gen_symversions_S)
- $(call cmd,warn_shared_object)
-endef
-
# Built-in and composite module parts
$(obj)/%.o: $(obj)/%.c $(recordmcount_source) FORCE
$(call if_changed_rule,cc_o_c)
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 73e385946855..17c81c346e36 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -302,14 +302,33 @@ endef
# ===========================================================================
# These are shared by some Makefile.* files.

+objtool-enabled := y
+
quiet_cmd_cc_o_c = CC $(quiet_modtag) $@
cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< \
$(cmd_ld_single_m) \
$(cmd_objtool)

+define rule_cc_o_c
+ $(call cmd_and_fixdep,cc_o_c)
+ $(call cmd,checksrc)
+ $(call cmd,checkdoc)
+ $(call cmd,gen_objtooldep)
+ $(call cmd,gen_symversions_c)
+ $(call cmd,record_mcount)
+ $(call cmd,warn_shared_object)
+endef
+
quiet_cmd_as_o_S = AS $(quiet_modtag) $@
cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< $(cmd_objtool)

+define rule_as_o_S
+ $(call cmd_and_fixdep,as_o_S)
+ $(call cmd,gen_objtooldep)
+ $(call cmd,gen_symversions_S)
+ $(call cmd,warn_shared_object)
+endef
+
# Copy a file
# ===========================================================================
# 'cp' preserves permissions. If you use it to copy a file in read-only srctree,
diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal
index d0153d033bbb..0547a4b59f13 100644
--- a/scripts/Makefile.modfinal
+++ b/scripts/Makefile.modfinal
@@ -26,10 +26,10 @@ KCSAN_SANITIZE := n
ccflags-remove-y := $(CC_FLAGS_CFI)

%.mod.o: %.mod.c FORCE
- $(call if_changed_dep,cc_o_c)
+ $(call if_changed_rule,cc_o_c)

.module-common.o: $(srctree)/scripts/module-common.c FORCE
- $(call if_changed_dep,cc_o_c)
+ $(call if_changed_rule,cc_o_c)

quiet_cmd_ld_ko_o = LD [M] $@
cmd_ld_ko_o = \
diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux
index 1652561896eb..83fc1a861f41 100644
--- a/scripts/Makefile.vmlinux
+++ b/scripts/Makefile.vmlinux
@@ -12,10 +12,10 @@ include $(srctree)/scripts/Makefile.lib
targets :=

%.o: %.c FORCE
- $(call if_changed_dep,cc_o_c)
+ $(call if_changed_rule,cc_o_c)

%.o: %.S FORCE
- $(call if_changed_dep,as_o_S)
+ $(call if_changed_rule,as_o_S)

# Built-in dtb
# ---------------------------------------------------------------------------
--
2.43.0