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Date: Thu, 10 May 2018 23:11:37 +1000
From: Nicholas Piggin <npiggin@gmail.com>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kbuild@vger.kernel.org, Masahiro Yamada
 <yamada.masahiro@socionext.com>, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2 4/5] powerpc/kbuild: Use flags variables rather than
 overriding LD/CC/AS
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On Thu, 10 May 2018 23:03:08 +1000
Michael Ellerman <mpe@ellerman.id.au> wrote:

> Nicholas Piggin <npiggin@gmail.com> writes:
> 
> > The powerpc toolchain can compile combinations of 32/64 bit and
> > big/little endian, so it's convenient to consider, e.g.,
> >
> >   `CC -m64 -mbig-endian`
> >
> > To be the C compiler for the purpose of invoking it to build target
> > artifacts. So overriding the the CC variable to include thse flags
> > works for this purpose.
> >
> > Unfortunately that is not compatible with the way the proposed new
> > Kconfig macro language will work.
> >
> > After previous patches in this series, these flags can be carefully
> > passed in using flags instead.
> >
> > Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> > ---
> >  arch/powerpc/Makefile   | 16 +++++++++-------
> >  scripts/recordmcount.pl |  8 ++++++++  
> 
> We should probably at least Cc Rostedt on the recordmcount.pl change.

Sure I'll send another iteration after some more time for reviews and
cc him on it.

> 
> > diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl
> > index 191eb949d52c..919711dd9d6c 100755
> > --- a/scripts/recordmcount.pl
> > +++ b/scripts/recordmcount.pl
> > @@ -274,6 +274,14 @@ if ($arch eq "x86_64") {  
> 
> Despite what the above says you're patching the powerpc entry AFAICS, so
> I guess that's pretty harmless.

Yeah I didn't think it was worth a separate patch.

> 
> >      if ($bits == 64) {
> >  	$type = ".quad";
> >      }
> > +    $ld .= " -EB ";
> > +    if ($endian eq "big") {
> > +	    $cc .= " -mbig-endian ";
> > +	    $ld .= " -EB ";  
> 
> Don't we end up with two "-EB"s for the big endian case?
> 
> Or do I understand perl even less than I thought I did?

No I was testing things and that's leaked into the commit. Good eye. I
think it worked for le because the next -EL will override the first -EB,
but I'll take that out.

Thanks,
Nick