Re: [PATCH v2 05/16] powerpc: Skip objtool from running on drivers/crypto/vmx/aesp8-ppc.o

[Naveen N. Rao]

Peter Zijlstra wrote:
> On Mon, Aug 29, 2022 at 11:22:12AM +0530, Sathvika Vasireddy wrote:
> > With objtool enabled, below warnings are seen when trying to build:
> >
> > drivers/crypto/vmx/aesp8-ppc.o: warning: objtool: aes_p8_set_encrypt_key+0x44: unannotated intra-function call
> >
> > drivers/crypto/vmx/aesp8-ppc.o: warning: objtool: .text+0x2448: unannotated intra-function call
> >
> > drivers/crypto/vmx/aesp8-ppc.o: warning: objtool: .text+0x2d68: unannotated intra-function call
> >
> > Skip objtool from running on this file, for two main reasons:
> >
> > Since this file comes from OpenSSL, and since it is a perl file
> > which generates a .S file, it may not be the best choice to
> > make too many code changes to such files, unless absolutely
> > necessary.
> >
> > Second reason is that, at least as far as the objtool --mcount
> > functionality is concerned, we do not have to run objtool on
> > that file because that file does not have any calls to _mcount.
> >
> > Signed-off-by: Sathvika Vasireddy <sv@xxxxxxxxxxxxx>
> > ---
> >  drivers/crypto/vmx/Makefile | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/crypto/vmx/Makefile b/drivers/crypto/vmx/Makefile
> > index 2560cfea1dec..7b41f0da6807 100644
> > --- a/drivers/crypto/vmx/Makefile
> > +++ b/drivers/crypto/vmx/Makefile
> > @@ -9,3 +9,5 @@ targets += aesp8-ppc.S ghashp8-ppc.S
> >  
> >  $(obj)/aesp8-ppc.S $(obj)/ghashp8-ppc.S: $(obj)/%.S: $(src)/%.pl FORCE
> >  	$(call if_changed,perl)
> > +
> > +OBJECT_FILES_NON_STANDARD_aesp8-ppc.o := y
>
> Just be aware that the moment you start to run objtool on vmlinux.o this
> annotation becomes unstuck.
>
> Specifically things like LTO builds require this because there simply
> isn't an object file before that.

Good point. LTO isn't supported today with ftrace on powerpc, so I guess 
we are ok with this patch for now.

To add LTO support, I guess we will need to add some annotations to this 
file later on.


- Naveen