Re: [PATCH v2 07/12] kbuild: Only run objtool if there is at least one command

[Nicolas Schier <nsc@kernel.org>]

On Tue, Mar 17, 2026 at 03:51:07PM -0700, Josh Poimboeuf wrote:
> Split the objtool args into commands and options, such that if no
> commands have been enabled, objtool doesn't run.
> 
> This is in preparation in enabling objtool and klp-build for arm64.
> 
> Reviewed-by: Nathan Chancellor <nathan@kernel.org>
> Tested-by: Nathan Chancellor <nathan@kernel.org>
> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
> ---
>  arch/x86/boot/startup/Makefile |  2 +-
>  scripts/Makefile.build         |  4 +--
>  scripts/Makefile.lib           | 46 ++++++++++++++++++----------------
>  scripts/Makefile.vmlinux_o     | 15 ++++-------
>  4 files changed, 33 insertions(+), 34 deletions(-)
> 
[...]
> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> index 3652b85be545..8a1bdfdb2fdb 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 = $(if $(is-standard-object),$(if $(objtool-cmds-y),$(if $(delay-objtool),$(is-single-obj-m),y)))

Please use $(and a,b,c) instead of multiple nested $(if $(a),$(if
$(b),$(c)); as the last variable (is-single-obj-m) is 'y' or empty, the final 'y' can be
left-out:

$(obj)/%.o: private objtool-enabled = $(and $(is-standard-object),$(objtool-cmds-y),$(delay-objtool),$(is-single-obj-m))

>  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))

Could be changed to $(and), too; but personally I think the $(if) is
easier to parse at once.


Reviewed-by: Nicolas Schier <nsc@kernel.org>

-- 
Nicolas