From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.12]) (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 99F291DFE2B; Thu, 5 Dec 2024 11:17:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733397430; cv=none; b=q+Mk4oUDg4lAfUu3AopIXV01rA52YFG/ugUjKALLfOnb8wkodXRPLuKV+lXbQjOWqqLMY6Ptv3n6C52ilzh28ixoGUIgeEmKb3D49LxBnEVHIvZtQZJC+W5nyUTLIdRsJhHNd+fXJUmwjWHR8kur3mimbop5VixWkhOmRI6pTvE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733397430; c=relaxed/simple; bh=RQkwyRD0doVFajjJ5Kd7+6rUV8dyJ/VQkaUXx4nT6Ls=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=SV5WgfuI4hyrJNazFOWLy0hdHGCqeIRm6hPGKCHgw50tPDDwtp+2bsbsY2021lFPjjzFKX6dTEtA/b0AyfHJP/IHICfp5RUY4b/8NlO4SFrbq0C7IhgEmHs+59igBReOT3hJ47TYqfDA0QJUdR2LWD91DNLVZxdhTvpB+mf08H4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=kernel.org; spf=fail smtp.mailfrom=kernel.org; arc=none smtp.client-ip=192.198.163.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=kernel.org Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=kernel.org X-CSE-ConnectionGUID: Ws9yMnk7SU+7FfyS6njkBw== X-CSE-MsgGUID: biEF8o+sRqCw4zEGmzhpjA== X-IronPort-AV: E=McAfee;i="6700,10204,11276"; a="37639116" X-IronPort-AV: E=Sophos;i="6.12,210,1728975600"; d="scan'208";a="37639116" Received: from orviesa003.jf.intel.com ([10.64.159.143]) by fmvoesa106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Dec 2024 03:17:08 -0800 X-CSE-ConnectionGUID: iDeKZM9URCS0267tyxyt4g== X-CSE-MsgGUID: oPViH0/YQmiuYgFtgjW/vg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.11,199,1725346800"; d="scan'208";a="99104601" Received: from smile.fi.intel.com ([10.237.72.154]) by orviesa003.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Dec 2024 03:17:05 -0800 Received: from andy by smile.fi.intel.com with local (Exim 4.98) (envelope-from ) id 1tJ9qv-000000044BE-02lr; Thu, 05 Dec 2024 13:17:01 +0200 Date: Thu, 5 Dec 2024 13:17:00 +0200 From: Andy Shevchenko To: Arnd Bergmann Cc: Linus Torvalds , Arnd Bergmann , linux-kernel@vger.kernel.org, x86@kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Matthew Wilcox , Sean Christopherson , Davide Ciminaghi , Paolo Bonzini , kvm@vger.kernel.org Subject: Re: [PATCH 09/11] x86: rework CONFIG_GENERIC_CPU compiler flags Message-ID: References: <20241204103042.1904639-1-arnd@kernel.org> <20241204103042.1904639-10-arnd@kernel.org> <74e8e9c6-8205-413a-97a4-aae32042c019@app.fastmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <74e8e9c6-8205-413a-97a4-aae32042c019@app.fastmail.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo On Thu, Dec 05, 2024 at 11:09:41AM +0100, Arnd Bergmann wrote: > On Thu, Dec 5, 2024, at 09:13, Andy Shevchenko wrote: > > On Wed, Dec 04, 2024 at 03:33:19PM -0800, Linus Torvalds wrote: > >> On Wed, 4 Dec 2024 at 11:44, Arnd Bergmann wrote: ... > >> Will that work when you cross-compile? No. Do we care? Also no. It's > >> basically a simple "you want to optimize for your own local machine" > >> switch. > > > > Maybe it's okay for 64-bit machines, but for cross-compiling for 32-bit on > > 64-bit. I dunno what '-march=native -m32' (or equivalent) will give in such > > cases. > > From the compiler's perspective this is nothing special, it just > builds a 32-bit binary that can use any instruction supported in > 32-bit mode of that 64-bit CPU, But does this affect building, e.g., for Quark on my Skylake desktop? > the same as the 32-bit CONFIG_MCORE2 option that I disallow in patch 04/11. -- With Best Regards, Andy Shevchenko