[RFC PATCH v2 5/7] objtool: Enable objtool to run only on files with ftrace enabled

[Peter Zijlstra]

On Tue, May 24, 2022 at 08:01:39PM +0200, Peter Zijlstra wrote:
> On Tue, May 24, 2022 at 03:17:45PM +0200, Christophe Leroy wrote:
> > From: Sathvika Vasireddy <sv at linux.ibm.com>
> > 
> > This patch makes sure objtool runs only on the object files
> > that have ftrace enabled, instead of running on all the object
> > files.
> > 
> > Signed-off-by: Naveen N. Rao <naveen.n.rao at linux.vnet.ibm.com>
> > Signed-off-by: Sathvika Vasireddy <sv at linux.ibm.com>
> > Signed-off-by: Christophe Leroy <christophe.leroy at csgroup.eu>
> > ---
> >  scripts/Makefile.build | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> > index 2e0c3f9c1459..06ceffd92921 100644
> > --- a/scripts/Makefile.build
> > +++ b/scripts/Makefile.build
> > @@ -258,8 +258,8 @@ else
> >  # 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
> >  # 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
> >  
> > -$(obj)/%.o: objtool-enabled = $(if $(filter-out y%, \
> > -	$(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n),y)
> > +$(obj)/%.o: objtool-enabled = $(and $(if $(filter-out y%, $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n),y),        \
> > +        $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)),y),y)
> 
> I think this breaks x86, quite a bit of files have ftrace disabled but
> very much must run objtool anyway.

Also; since the Changelog gives 0 clue as to what problem it's trying to
solve, I can't suggest anything.