Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756840AbYGRKxZ (ORCPT ); Fri, 18 Jul 2008 06:53:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754844AbYGRKxR (ORCPT ); Fri, 18 Jul 2008 06:53:17 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:37804 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754412AbYGRKxR (ORCPT ); Fri, 18 Jul 2008 06:53:17 -0400 Date: Fri, 18 Jul 2008 12:52:59 +0200 From: Ingo Molnar To: "Maciej W. Rozycki" Cc: x86@kernel.org, linux-kernel@vger.kernel.org, Suresh Siddha , Yinghai Lu , Jeremy Fitzhardinge Subject: Re: [PATCH] x86: APIC: Remove apic_write_around(); use alternatives Message-ID: <20080718105259.GY6875@elte.hu> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1667 Lines: 35 * Maciej W. Rozycki wrote: > Use alternatives to select the workaround for the 11AP Pentium > erratum for the affected steppings on the fly rather than build time. > Remove the X86_GOOD_APIC configuration option and replace all the > calls to apic_write_around() with plain apic_write(), protecting > accesses to the ESR as appropriate due to the 3AP Pentium erratum. > Remove apic_read_around() and all its invocations altogether as not > needed. Remove apic_write_atomic() and all its implementing backends. > The use of ASM_OUTPUT2() is not strictly needed for input constraints, > but I have used it for readability's sake. wow, impressive patch! > I had the feeling no one else was brave enough to do it, so I went > ahead and here it is. Verified by checking the generated assembly and > tested with both a 32-bit and a 64-bit configuration, also with the > 11AP "feature" forced on and verified with gdb on /proc/kcore to work > as expected (as an 11AP machines are quite hard to get hands on these > days). Some script complained about the use of "volatile", but > apic_write() needs it for the same reason and is effectively a > replacement for writel(), so I have disregarded it. kudos for pulling this off :-) applied to tip/x86/apic. This will interact with tip/x86/x2apic but that topic is being worked on anyway. The interaction should be trivial. Ingo -- 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/