Re: [PATCH] powerpc: remove meaningless KBUILD_ARFLAGS addition

From: Michael Ellerman <mpe@ellerman.id.au>
To: Segher Boessenkool <segher@kernel.crashing.org>,
	Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>,
	linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
	Paul Mackerras <paulus@samba.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Nicholas Piggin <npiggin@gmail.com>
Subject: Re: [PATCH] powerpc: remove meaningless KBUILD_ARFLAGS addition
Date: Fri, 19 Jul 2019 13:39:08 +1000	[thread overview]
Message-ID: <87blxq8zhf.fsf@concordia.ellerman.id.au> (raw)
In-Reply-To: <20190718204631.GV20882@gate.crashing.org>

Segher Boessenkool <segher@kernel.crashing.org> writes:
> On Thu, Jul 18, 2019 at 11:19:58AM +0900, Masahiro Yamada wrote:
>> On Thu, Jul 18, 2019 at 1:46 AM Segher Boessenkool
>> <segher@kernel.crashing.org> wrote:
>> Kbuild always uses thin archives as far as vmlinux is concerned.
>> 
>> But, there are some other call-sites.
>> 
>> masahiro@pug:~/ref/linux$ git grep  '$(AR)' -- :^Documentation :^tools
>> arch/powerpc/boot/Makefile:    BOOTAR := $(AR)
>> arch/unicore32/lib/Makefile:    $(Q)$(AR) p $(GNU_LIBC_A) $(notdir $@) > $@
>> arch/unicore32/lib/Makefile:    $(Q)$(AR) p $(GNU_LIBGCC_A) $(notdir $@) > $@
>> lib/raid6/test/Makefile:         $(AR) cq $@ $^
>> scripts/Kbuild.include:ar-option = $(call try-run, $(AR) rc$(1)
>> "$$TMP",$(1),$(2))
>> scripts/Makefile.build:      cmd_ar_builtin = rm -f $@; $(AR)
>> rcSTP$(KBUILD_ARFLAGS) $@ $(real-prereqs)
>> scripts/Makefile.lib:      cmd_ar = rm -f $@; $(AR)
>> rcsTP$(KBUILD_ARFLAGS) $@ $(real-prereqs)
>> 
>> Probably, you are interested in arch/powerpc/boot/Makefile.
>
> That one seems fine actually.  The raid6 one I don't know.
>
>
> My original commit message was
>
>     Without this, some versions of GNU ar fail to create
>     an archive index if the object files it is packing
>     together are of a different object format than ar's
>     default format (for example, binutils compiled to
>     default to 64-bit, with 32-bit objects).
>
> but I cannot reproduce the problem anymore.  Shortly after my patch the
> thin archive code happened to binutils, and that overhauled some other
> things, which might have fixed it already?
>
>> > Yes, I know.  This isn't about built-in.[oa], it is about *other*
>> > archives we at least *used to* create.  If we *know* we do not anymore,
>> > then this workaround can of course be removed (and good riddance).
>> 
>> If it is not about built-in.[oa],
>> which archive are you talking about?
>> 
>> Can you pin-point the one?
>
> No, not anymore.  Lost in the mists of time, I guess?  I think we'll
> just have to file it as "it seems to work fine now".

Yeah I think so. If someone finds a case it breaks we can fix it then.

> Thank you (and everyone else) for the time looking at this!

Likewise.

cheers