Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753379Ab0BQRjR (ORCPT ); Wed, 17 Feb 2010 12:39:17 -0500 Received: from cantor2.suse.de ([195.135.220.15]:57659 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752514Ab0BQRjP (ORCPT ); Wed, 17 Feb 2010 12:39:15 -0500 Message-ID: <4B7C29C1.10906@suse.cz> Date: Wed, 17 Feb 2010 18:39:13 +0100 From: Michal Marek User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.5) Gecko/20091130 SUSE/3.0.0-1.2 Thunderbird/3.0 MIME-Version: 1.0 To: Borislav Petkov Cc: "H. Peter Anvin" , linux-kbuild , Borislav Petkov , Peter Zijlstra , Andrew Morton , Wu Fengguang , LKML , Jamie Lokier , Roland Dreier , Al Viro , "linux-fsdevel@vger.kernel.org" , Ingo Molnar , Brian Gerst Subject: Re: [PATCH 2/5] bitops: compile time optimization for hweight_long(CONSTANT) References: <20100208092845.GB12618@a1.tnic> <4B6FDAED.9060204@zytor.com> <20100208095945.GA14740@a1.tnic> <20100211172424.GB19779@aftab> <4B743F7D.3090605@zytor.com> <20100212170649.GC3114@aftab> <4B758FC0.1020600@zytor.com> <20100212174751.GD3114@aftab> <4B75A66A.70005@zytor.com> <4B7BF5D6.3030701@suse.cz> <20100217172040.GC13429@aftab> <4B7C27D8.9050408@suse.cz> In-Reply-To: <4B7C27D8.9050408@suse.cz> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1636 Lines: 44 On 17.2.2010 18:31, Michal Marek wrote: > On 17.2.2010 18:20, Borislav Petkov wrote: >> On Wed, Feb 17, 2010 at 02:57:42PM +0100, Michal Marek wrote: >>> On 12.2.2010 20:05, H. Peter Anvin wrote: >>>> On 02/12/2010 09:47 AM, Borislav Petkov wrote: >>>>> >>>>> However, this is generic code and for the above to work we have to >>>>> enforce x86-specific CFLAGS for it. What is the preferred way to do >>>>> that? >>>>> >>>> >>>> That's a question for Michal and the kbuild list. Michal? >>> >>> (I was offline last week). >>> >>> The _preferred_ way probably is not to do it :), but otherwise you can >>> set CFLAGS_hweight.o depending on CONFIG_X86(_32|_64), just like you do >>> in arch/x86/lib/Makefile already. >> >> Wouldn't it be better if we had something like ARCH_CFLAGS_hweight.o >> which gets set in the arch Makefile instead? > > We could, but is it worth it if there is only one potential user so far? > IMO just put the condition to lib/Makefile now and if there turn out to > be more cases like this, we can add support for ARCH_CFLAGS_foo.o then. It wouldn't work actually, because such variable would then apply to all hweight.o targets in the tree. But another way would be: arch/x86/Kconfig config ARCH_HWEIGHT_CFLAGS string default "..." if X86_32 default "..." if X86_64 lib/Makefile CFLAGS_hweight.o = $(CONFIG_ARCH_HWEIGHT_CFLAGS) Michal -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/