[PATCH v3 09/21] kbuild: Only run objtool if there is at least one command

Split the objtool args into commands and options, such that if no
commands have been enabled, objtool doesn't run.

This is in preparation for enabling objtool and klp-build for arm64.

Reviewed-by: Nathan Chancellor <[email protected]>
Reviewed-by: Nicolas Schier <[email protected]>
Tested-by: Nathan Chancellor <[email protected]>
Signed-off-by: Josh Poimboeuf <[email protected]>
---
 arch/x86/boot/startup/Makefile |  2 +-
 scripts/Makefile.build         |  4 +--
 scripts/Makefile.lib           | 52 ++++++++++++++++++----------------
 scripts/Makefile.vmlinux_o     | 15 ++++------
 4 files changed, 36 insertions(+), 37 deletions(-)

diff --git a/arch/x86/boot/startup/Makefile b/arch/x86/boot/startup/Makefile
index 5e499cfb29b5c..a08297829fc63 100644
--- a/arch/x86/boot/startup/Makefile
+++ b/arch/x86/boot/startup/Makefile
@@ -36,7 +36,7 @@ $(patsubst %.o,$(obj)/%.o,$(lib-y)): OBJECT_FILES_NON_STANDARD := y
 # relocations, even if other objtool actions are being deferred.
 #
 $(pi-objs): objtool-enabled	= 1
-$(pi-objs): objtool-args	= $(if $(delay-objtool),--dry-run,$(objtool-args-y)) --noabs
+$(pi-objs): objtool-args	= $(if $(delay-objtool),--dry-run,$(objtool-cmds-y) $(objtool-opts-y)) --noabs
 
 #
 # Confine the startup code by prefixing all symbols with __pi_ (for position
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 3498d25b15e85..c4accfcd177d4 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -277,7 +277,7 @@ endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
 is-standard-object = $(if $(filter-out y%, $(OBJECT_FILES_NON_STANDARD_$(target-stem).o)$(OBJECT_FILES_NON_STANDARD)n),$(is-kernel-object))
 
 ifdef CONFIG_OBJTOOL
-$(obj)/%.o: private objtool-enabled = $(if $(is-standard-object),$(if $(delay-objtool),$(is-single-obj-m),y))
+$(obj)/%.o: private objtool-enabled = $(and $(is-standard-object),$(objtool-cmds-y),$(if $(delay-objtool),$(is-single-obj-m),y))
 endif
 
 ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),)
@@ -501,7 +501,7 @@ define rule_ld_multi_m
 	$(call cmd,gen_objtooldep)
 endef
 
-$(multi-obj-m): private objtool-enabled := $(delay-objtool)
+$(multi-obj-m): private objtool-enabled := $(if $(objtool-cmds-y),$(delay-objtool))
 $(multi-obj-m): private part-of-module := y
 $(multi-obj-m): %.o: %.mod FORCE
 	$(call if_changed_rule,ld_multi_m)
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 7e216d82e9887..7f803796d20cf 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -183,30 +183,34 @@ ifdef CONFIG_OBJTOOL
 
 objtool := $(objtree)/tools/objtool/objtool
 
-objtool-args-$(CONFIG_HAVE_JUMP_LABEL_HACK)		+= --hacks=jump_label
-objtool-args-$(CONFIG_HAVE_NOINSTR_HACK)		+= --hacks=noinstr
-objtool-args-$(CONFIG_MITIGATION_CALL_DEPTH_TRACKING)	+= --hacks=skylake
-objtool-args-$(CONFIG_X86_KERNEL_IBT)			+= --ibt
-objtool-args-$(CONFIG_CALL_PADDING)			+= --prefix=$(CONFIG_FUNCTION_PADDING_BYTES)
-ifdef CONFIG_CALL_PADDING
-objtool-args-$(CONFIG_CFI)				+= --cfi
-objtool-args-$(CONFIG_FINEIBT)				+= --fineibt
-endif
-objtool-args-$(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL)	+= --mcount
-ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL
-objtool-args-$(CONFIG_HAVE_OBJTOOL_NOP_MCOUNT)		+= --mnop
-endif
-objtool-args-$(CONFIG_UNWINDER_ORC)			+= --orc
-objtool-args-$(CONFIG_MITIGATION_RETPOLINE)		+= --retpoline
-objtool-args-$(CONFIG_MITIGATION_RETHUNK)		+= --rethunk
-objtool-args-$(CONFIG_MITIGATION_SLS)			+= --sls
-objtool-args-$(CONFIG_STACK_VALIDATION)			+= --stackval
-objtool-args-$(CONFIG_HAVE_STATIC_CALL_INLINE)		+= --static-call
-objtool-args-$(CONFIG_HAVE_UACCESS_VALIDATION)		+= --uaccess
-objtool-args-$(or $(CONFIG_GCOV_KERNEL),$(CONFIG_KCOV))	+= --no-unreachable
-objtool-args-$(CONFIG_OBJTOOL_WERROR)			+= --werror
+# objtool commands
+objtool-cmds-$(CONFIG_HAVE_JUMP_LABEL_HACK)		+= --hacks=jump_label
+objtool-cmds-$(CONFIG_HAVE_NOINSTR_HACK)		+= --hacks=noinstr
+objtool-cmds-$(CONFIG_MITIGATION_CALL_DEPTH_TRACKING)	+= --hacks=skylake
+objtool-cmds-$(CONFIG_X86_KERNEL_IBT)			+= --ibt
+objtool-cmds-$(CONFIG_CALL_PADDING)			+= --prefix=$(CONFIG_FUNCTION_PADDING_BYTES)
+objtool-cmds-$(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL)	+= --mcount
+objtool-cmds-$(CONFIG_UNWINDER_ORC)			+= --orc
+objtool-cmds-$(CONFIG_MITIGATION_RETPOLINE)		+= --retpoline
+objtool-cmds-$(CONFIG_MITIGATION_RETHUNK)		+= --rethunk
+objtool-cmds-$(CONFIG_MITIGATION_SLS)			+= --sls
+objtool-cmds-$(CONFIG_STACK_VALIDATION)			+= --stackval
+objtool-cmds-$(CONFIG_HAVE_STATIC_CALL_INLINE)		+= --static-call
+objtool-cmds-$(CONFIG_HAVE_UACCESS_VALIDATION)		+= --uaccess
+objtool-cmds-y						+= $(OBJTOOL_ARGS)
 
-objtool-args = $(objtool-args-y)					\
+# objtool options
+ifdef CONFIG_CALL_PADDING
+objtool-opts-$(CONFIG_CFI)				+= --cfi
+objtool-opts-$(CONFIG_FINEIBT)				+= --fineibt
+endif
+ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL
+objtool-opts-$(CONFIG_HAVE_OBJTOOL_NOP_MCOUNT)		+= --mnop
+endif
+objtool-opts-$(or $(CONFIG_GCOV_KERNEL),$(CONFIG_KCOV))	+= --no-unreachable
+objtool-opts-$(CONFIG_OBJTOOL_WERROR)			+= --werror
+
+objtool-args = $(objtool-cmds-y) $(objtool-opts-y)			\
 	$(if $(delay-objtool), --link)					\
 	$(if $(part-of-module), --module)
 
@@ -215,7 +219,7 @@ delay-objtool := $(or $(CONFIG_LTO_CLANG),$(CONFIG_X86_KERNEL_IBT),$(CONFIG_KLP_
 cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool-args) $@)
 cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$@: $$(wildcard $(objtool))' ; } >> $(dot-target).cmd)
 
-objtool-enabled := y
+objtool-enabled = $(if $(objtool-cmds-y),y)
 
 endif # CONFIG_OBJTOOL
 
diff --git a/scripts/Makefile.vmlinux_o b/scripts/Makefile.vmlinux_o
index 527352c222ff6..09af33203bd8d 100644
--- a/scripts/Makefile.vmlinux_o
+++ b/scripts/Makefile.vmlinux_o
@@ -36,18 +36,13 @@ endif
 # For !delay-objtool + CONFIG_NOINSTR_VALIDATION, it runs on both translation
 # units and vmlinux.o, with the latter only used for noinstr/unret validation.
 
-objtool-enabled := $(or $(delay-objtool),$(CONFIG_NOINSTR_VALIDATION))
-
-ifeq ($(delay-objtool),y)
-vmlinux-objtool-args-y					+= $(objtool-args-y)
-else
-vmlinux-objtool-args-$(CONFIG_OBJTOOL_WERROR)		+= --werror
+ifneq ($(delay-objtool),y)
+objtool-cmds-y					 =
+objtool-opts-y					+= --link
 endif
 
-vmlinux-objtool-args-$(CONFIG_NOINSTR_VALIDATION)	+= --noinstr \
-							   $(if $(or $(CONFIG_MITIGATION_UNRET_ENTRY),$(CONFIG_MITIGATION_SRSO)), --unret)
-
-objtool-args = $(vmlinux-objtool-args-y) --link
+objtool-cmds-$(CONFIG_NOINSTR_VALIDATION)	+= --noinstr \
+						   $(if $(or $(CONFIG_MITIGATION_UNRET_ENTRY),$(CONFIG_MITIGATION_SRSO)), --unret)
 
 # Link of vmlinux.o used for section mismatch analysis
 # ---------------------------------------------------------------------------
-- 
2.53.0