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From:   Masahiro Yamada <yamada.masahiro@socionext.com>
Date:   Mon, 15 Jul 2019 21:03:46 +0900
Message-ID: <CAK7LNATGEK9wxz87J3sTNOYPdtAFXaegQU9EctEBGULQL-ZC4w@mail.gmail.com>
Subject: Re: [PATCH] powerpc: remove meaningless KBUILD_ARFLAGS addition
To:     Segher Boessenkool <segher@kernel.crashing.org>
Cc:     Michael Ellerman <mpe@ellerman.id.au>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Nicholas Piggin <npiggin@gmail.com>,
        Paul Mackerras <paulus@samba.org>,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
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On Mon, Jul 15, 2019 at 4:30 PM Segher Boessenkool
<segher@kernel.crashing.org> wrote:
>
> On Mon, Jul 15, 2019 at 05:05:34PM +1000, Michael Ellerman wrote:
> > Segher Boessenkool <segher@kernel.crashing.org> writes:
> > > Yes, that is why I used the environment variable, all binutils work
> > > with that.  There was no --target option in GNU ar before 2.22.

I use binutils 2.30
It does not understand --target option.

$ powerpc-linux-ar --version
GNU ar (GNU Binutils) 2.30
Copyright (C) 2018 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License version 3 or (at your option) any later version.
This program has absolutely no warranty.

If I give --target=elf$(BITS)-$(GNUTARGET) option, I see this:
powerpc-linux-ar: -t: No such file or directory


> > Yeah, we're not very good at testing with really old binutils, so I
> > guess we broke that.
> >
> > I'm inclined to merge this, it doesn't seem to break anything, and it
> > fixes using --target on old binutils that don't have it.
>
> But we don't set the target any other way either.  I don't think this
> will work with a 32-bit toolchain (default target 32 bit) and a 64-bit
> kernel, or the other way around.
>
> Then again, does that work at *all* nowadays?  Do we even consider that
> important, *should* it work?


Let me confirm if I understood this discussion.


[1] KBUILD_ARFLAGS += --target=elf$(BITS)-$(GNUTARGET)
    is pointless since it is always overridden by another
    KBUILD_ARFLAGS assignment.

[2] If we stop overriding it, it would cause build errors.
    So, --target is not only useless, but it is rather harmful.


So, we all agreed with this patch, right?


We are discussing whether or not to revive
GNUTARGET=elf$(BITS)-$(GNUTARGET)
in a *separate* patch, correct?


-- 
Best Regards
Masahiro Yamada