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

From: Nicolas Schier <[email-masked]>
Date: Mon, 30 Mar 2026 20:49:20 +0200

On Wed, Mar 18, 2026 at 05:49:27PM -0700, Josh Poimboeuf wrote:
> On Wed, Mar 18, 2026 at 08:54:31PM +0100, Nicolas Schier wrote:
> > 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 <[email-masked]>
> > > Tested-by: Nathan Chancellor <[email-masked]>
> > > Signed-off-by: Josh Poimboeuf <[email-masked]>
> > > ---
> > >  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))
> 
> I believe that would break the !delay-objtool case.  The logic needs to
> be something like:
> 
> if (is-standard-object && objtool-cmds-y) {
> 	if (delay-objtool) {
> 		// for delay-objtool, only enable objtool for single-object modules
> 		$(is-single-obj-m)
> 	} else {
> 		// for !delay-objtool, always enable objtool
> 		y
> 	}
> }
> 
> so maybe something like this?
> 
> $(obj)/%.o: private objtool-enabled = $(and $(is-standard-object),$(objtool-cmds-y),$(if $(delay-objtool),$(is-single-obj-m),y))

sorry for the delay!  Yes, I overlooked the !delay-objtool.  That line
looks good to me, thanks!

-- 
Nicolas