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 0EFF0C43219 for ; Tue, 8 Nov 2022 18:30:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230349AbiKHSau (ORCPT ); Tue, 8 Nov 2022 13:30:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46132 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230340AbiKHSar (ORCPT ); Tue, 8 Nov 2022 13:30:47 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 01C955B866 for ; Tue, 8 Nov 2022 10:30:43 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 9371461710 for ; Tue, 8 Nov 2022 18:30:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 69817C433C1; Tue, 8 Nov 2022 18:30:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1667932242; bh=0Ilpd65+BqZHkJQ6ZzbRrBM6rJYVbLuq+YBsux3JXtU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pV+UF3UaA6L7a+E88bOAIYaofBJsNItjRIIp3Jlu2QNTC3apAw8yYtAk+CVMTfgm5 rz0hygtGXgPBOAoF4MHtAuwdzOfIB0vXZAqJuzLsY/gZpH89buSqCV2iVsFlUSLWlm zxEgViHEw+iFEVPiVmw5K9HJjmCfsj3S1fmT1RYmrNfe9R4EgFFSboeR/hsEFBnvHj KUJjN23BnQNWUe9p2Y7n9sEqrx5N+htE8lNqd+OO8m4NSir4tKZxDUS/pZ7Mv9dP48 85XsYet31gQhw49YZlx4eaXtlDURRhZntRbD7MozZtqekekKjIEY7v5TZvNcy7k6k5 CUY/yfbKcuWUA== Date: Tue, 8 Nov 2022 11:30:39 -0700 From: Nathan Chancellor To: Russell King , Nick Desaulniers Cc: Arnd Bergmann , Ard Biesheuvel , Masahiro Yamada , Linus Walleij , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev Subject: Re: [PATCH v4 2/4] ARM: use .arch directives instead of assembler command line flags Message-ID: References: <20221014201354.3190007-1-ndesaulniers@google.com> <20221014201354.3190007-3-ndesaulniers@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221014201354.3190007-3-ndesaulniers@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Russell, On Fri, Oct 14, 2022 at 01:13:52PM -0700, Nick Desaulniers wrote: > Similar to commit a6c30873ee4a ("ARM: 8989/1: use .fpu assembler > directives instead of assembler arguments"). > > GCC and GNU binutils support setting the "sub arch" via -march=, > -Wa,-march, target function attribute, and .arch assembler directive. > > Clang was missing support for -Wa,-march=, but this was implemented in > clang-13. > > The behavior of both GCC and Clang is to > prefer -Wa,-march= over -march= for assembler and assembler-with-cpp > sources, but Clang will warn about the -march= being unused. > > clang: warning: argument unused during compilation: '-march=armv6k' > [-Wunused-command-line-argument] > > Since most assembler is non-conditionally assembled with one sub arch > (modulo arch/arm/delay-loop.S which conditionally is assembled as armv4 > based on CONFIG_ARCH_RPC, and arch/arm/mach-at91/pm-suspend.S which is > conditionally assembled as armv7-a based on CONFIG_CPU_V7), prefer the > .arch assembler directive. > > Add a few more instances found in compile testing as found by Arnd and > Nathan. > > Link: https://github.com/llvm/llvm-project/commit/1d51c699b9e2ebc5bcfdbe85c74cc871426333d4 > Link: https://bugs.llvm.org/show_bug.cgi?id=48894 > Link: https://github.com/ClangBuiltLinux/linux/issues/1195 > Link: https://github.com/ClangBuiltLinux/linux/issues/1315 > Suggested-by: Arnd Bergmann > Suggested-by: Nathan Chancellor > Signed-off-by: Arnd Bergmann > Signed-off-by: Nick Desaulniers > --- > Changes v3 -> v4: > * Add .arch armv7-a to arch/arm/mach-tegra/sleep.S as per Nathan. > https://github.com/ClangBuiltLinux/linux/issues/1315#issuecomment-1255646893 > * Add Nathan's SB tag. I noticed that this series appears to be partially applied in next-20221108: 59247fe730db ARM: 9265/1: pass -march= only to compiler bc21212c5564 ARM: 9264/1: only use -mtp=cp15 for the compiler 5aa4860eb50f ARM: 9262/1: remove lazy evaluation in Makefile This patch (submitted as 9263/1) is needed by 9265/1; without it, builds are going to break: https://builds.tuxbuild.com/2HGSpQMAKxJuaMAz2ZZc1UgUvvu/build.log Was there a problem with applying this patch or just an oversight? It would be great to get this whole series applied so that we can turn -Wunused-command-line-argument into a hard error. Cheers, Nathan