From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 98529C5479D for ; Mon, 9 Jan 2023 22:38:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237854AbjAIWiN (ORCPT ); Mon, 9 Jan 2023 17:38:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55474 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237805AbjAIWiA (ORCPT ); Mon, 9 Jan 2023 17:38:00 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 53863F58C for ; Mon, 9 Jan 2023 14:37:59 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id BD14FCE1276 for ; Mon, 9 Jan 2023 22:37:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 430D9C433D2; Mon, 9 Jan 2023 22:37:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1673303875; bh=EIafaMbRLxZFbxacgDeKd6rkGJmiPZyvWttZF6Ltt7s=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jn9KUX0un9wox4UnYGcxi5TVftZua9ACI5dbU5bUh75/edM3LlOZh/fMiGVZgUqbh kcNLcAM+KLdmnUf6ZQzcv0zAl+knv+4oOc91C4FCrjiGn8I0j3Z8AhV6W66mdzityV NeOSFTsxdPKbePkPZbcZtyexZq4DEJkakXDnbdcQg+07noZccNQ15gSkkLhgPACxrw R8s43JvKbA1iuHYH06i9aBM7N73Bjkc1Tgj42uvuyNOmMk4H3AL4LqS0VfSe2cMbAG Lljs8jQ8K+/+cCaJPIomh4sQaShxiuNROmE7B6SFJdrB+IA6ylfEwGb/3VK9/WUSMf 3kVN7MlVR4L6g== Date: Mon, 9 Jan 2023 15:37:53 -0700 From: Nathan Chancellor To: Segher Boessenkool Cc: Nick Desaulniers , kernel test robot , linux-kbuild@vger.kernel.org, trix@redhat.com, masahiroy@kernel.org, llvm@lists.linux.dev, npiggin@gmail.com, linuxppc-dev@lists.ozlabs.org, nicolas@fjasle.eu Subject: Re: [PATCH 06/14] powerpc/vdso: Remove unused '-s' flag from ASFLAGS Message-ID: References: <20221228-drop-qunused-arguments-v1-0-658cbc8fc592@kernel.org> <20221228-drop-qunused-arguments-v1-6-658cbc8fc592@kernel.org> <20230109222337.GM25951@gate.crashing.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230109222337.GM25951@gate.crashing.org> Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org On Mon, Jan 09, 2023 at 04:23:37PM -0600, Segher Boessenkool wrote: > Hi! Happy new year all. > > On Mon, Jan 09, 2023 at 01:58:32PM -0800, Nick Desaulniers wrote: > > On Wed, Jan 4, 2023 at 11:55 AM Nathan Chancellor wrote: > > > > > > When clang's -Qunused-arguments is dropped from KBUILD_CPPFLAGS, it > > > warns that ASFLAGS contains '-s', which is a linking phase option, so it > > > is unused. > > > > > > clang-16: error: argument unused during compilation: '-s' [-Werror,-Wunused-command-line-argument] > > > > > > Looking at the GAS sources, '-s' is only useful when targeting Solaris > > > and it is ignored for the powerpc target so just drop the flag > > > altogether, as it is not needed. > > > > Do you have any more info where you found this? I don't see -s > > documented as an assembler flag. > > https://sourceware.org/binutils/docs/as/PowerPC_002dOpts.html > > https://sourceware.org/binutils/docs/as/Invoking.html > > It is required by POSIX (for the c99 command, anyway). It *also* is > required to be supported when producing object files (so when no linking > is done). > > It is a GCC flag, and documented just fine: > https://gcc.gnu.org/onlinedocs/gcc/Link-Options.html#index-s > > (Yes, that says it is for linking; but the option is allowed without > error of any kind always). > > (ASFLAGS sounds like it is for assembler commands, but it really is > for compiler commands that just happen to get .S input files). > > > The patch seems fine to me, but what was this ever supposed to be? > > FWICT it predates git history (looking at > > arch/powerpc/kernel/vdso32/Makefile at fc15351d9d63) > > Yeah, good question. This compiler flag does the moral equivalent of > strip -s (aka --strip-all). Maybe this was needed at some point, or > the symbol or debug info was just annoying (during bringup or similar)? > > > Reviewed-by: Nick Desaulniers > Reviewed-by: Segher Boessenkool Thank you for the review and extra explanation! I had kind of expanded on this in the s390 version of this patch [1], I will go ahead and do the same thing for the powerpc version too. [1]: https://lore.kernel.org/llvm/20221228-drop-qunused-arguments-v1-9-658cbc8fc592@kernel.org/ Cheers, Nathan