Date: Wed, 2 Mar 2016 21:20:58 -0600
From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Ingo Molnar <mingo@redhat.com>, x86@kernel.org,
        linux-kernel@vger.kernel.org,
        Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH 2/2] objtool: Support CROSS_COMPILE
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On Thu, Mar 03, 2016 at 01:43:14PM +1100, Stephen Rothwell wrote:
> Hi Josh,
> 
> Just a couple of quick comments ...
> 
> On Wed,  2 Mar 2016 18:39:37 -0600 Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> >
> > diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
> > index c4f0713..e4a6bd5 100644
> > --- a/tools/objtool/Makefile
> > +++ b/tools/objtool/Makefile
> 
> I was wondering if this would be more appropriate in scripts/objtool
> since it is used during the building of the kernel.  Or does it have a
> wider use?

Yeah, it was actually in the scripts/ dir in earlier revisions of the
patch set, for that very reason.  However, Ingo pointed out that it
could be useful beyond the kernel, so we graduated it to a "tool".

> > @@ -7,13 +7,19 @@ ARCH := x86
> >  endif
> >  endif
> >  
> > +# always use the host compiler
> > +CC = gcc
> 
> We have HOSTCC with its associated HOSTCFLAGS etc ... I am not sure if
> that is more appropriate (but it does take care of people using clang).

The "tools" are almost completely separate from the rest of the kernel.
They have their own scaled-down version of kbuild, which doesn't have
HOSTCC.

But yeah, we might eventually need to copy some of the host compilation
infrastructure from scripts/Makefile.host over to the tools/ side.

-- 
Josh