From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A6A963FCF for ; Thu, 16 Sep 2021 17:18:54 +0000 (UTC) Received: from zn.tnic (p200300ec2f11c6001e49ea6afe1054f5.dip0.t-ipconnect.de [IPv6:2003:ec:2f11:c600:1e49:ea6a:fe10:54f5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id A90881EC01A9; Thu, 16 Sep 2021 19:18:48 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1631812728; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=WGTaW9wzVo3mRbffUBHb/Jh9Yaw6al5FEDE3OWWucQM=; b=TnBBOysnTsIzYE72gUTor3/nH+wDVKctXHOhtc/8tJvJ/j4eB02Ry7TqHKbpKUvOhck0jO LUYPHx+QKc4wmuqnumvPn0qgaPqqDIo1/fPS99C0176oEdidy4Pb1TTVl3PKukfvPLakHP +F87tFSB+VUB5+uOz23N1vbudCUuSck= Date: Thu, 16 Sep 2021 19:18:42 +0200 From: Borislav Petkov To: Nathan Chancellor Cc: Thomas Gleixner , Ingo Molnar , x86@kernel.org, Masahiro Yamada , "H. Peter Anvin" , Nick Desaulniers , linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, clang-built-linux@googlegroups.com, llvm@lists.linux.dev, kernel test robot Subject: Re: [PATCH 1/2] x86: Do not add -falign flags unconditionally for clang Message-ID: References: <20210824022640.2170859-1-nathan@kernel.org> <20210824022640.2170859-2-nathan@kernel.org> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210824022640.2170859-2-nathan@kernel.org> On Mon, Aug 23, 2021 at 07:26:39PM -0700, Nathan Chancellor wrote: A couple of nitpicks: > Subject: [PATCH 1/2] x86: Do not add -falign flags unconditionally for clang Make that prefix into "x86/build: " > clang does not support -falign-jumps and only recently gained support > for -falign-loops. When one of the configuration options that adds these > flags is enabled, clang warns and all cc-{disable-warning,option} that > follow fail because -Werror gets added to test for the presence of this > warning: > > clang-14: warning: optimization flag '-falign-jumps=0' is not supported > [-Wignored-optimization-argument] > > To resolve this, add a couple of cc-option calls when building with > clang; gcc has supported these options since 3.2 so there is no point in > testing for their support. -falign-functions was implemented in clang-7, > -falign-loops was implemented in clang-14, and -falign-jumps has not > been implemented yet. > > Link: https://lore.kernel.org/r/YSQE2f5teuvKLkON@Ryzen-9-3900X.localdomain/ Also, there should be a second Link: tag which points to this mail thread so that we can find it later, when we dig for the "why we did that" question :) I.e., Link: 20210824022640.2170859-2-nathan@kernel.org > Reported-by: kernel test robot > Signed-off-by: Nathan Chancellor > --- > arch/x86/Makefile_32.cpu | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) with that: Acked-by: Borislav Petkov Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette