From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161603AbXD2XvF (ORCPT ); Sun, 29 Apr 2007 19:51:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161618AbXD2Xqu (ORCPT ); Sun, 29 Apr 2007 19:46:50 -0400 Received: from mx2.suse.de ([195.135.220.15]:38494 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161607AbXD2Xqe (ORCPT ); Sun, 29 Apr 2007 19:46:34 -0400 From: Andi Kleen References: <20070430146.588463000@suse.de> In-Reply-To: <20070430146.588463000@suse.de> To: Jeremy Fitzhardinge , patches@x86-64.org, linux-kernel@vger.kernel.org Subject: [PATCH] [23/26] i386: Allow boot-time disable of SMP altinstructions Message-Id: <20070429234633.40953150F2@wotan.suse.de> Date: Mon, 30 Apr 2007 01:46:33 +0200 (CEST) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Jeremy Fitzhardinge Add "noreplace-smp" to disable SMP instruction replacement. Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Andi Kleen --- Documentation/kernel-parameters.txt | 6 ++++++ arch/i386/kernel/alternative.c | 23 +++++++++++++++++++---- 2 files changed, 25 insertions(+), 4 deletions(-) =================================================================== Index: linux/Documentation/kernel-parameters.txt =================================================================== --- linux.orig/Documentation/kernel-parameters.txt +++ linux/Documentation/kernel-parameters.txt @@ -1142,6 +1142,9 @@ and is between 256 and 4096 characters. nomce [IA-32] Machine Check Exception + noreplace-smp [IA-32,SMP] Don't replace SMP instructions + with UP alternatives + noresidual [PPC] Don't use residual data on PReP machines. noresume [SWSUSP] Disables resume and restores original swap @@ -1547,6 +1550,9 @@ and is between 256 and 4096 characters. smart2= [HW] Format: [,[,...,]] + smp-alt-once [IA-32,SMP] On a hotplug CPU system, only + attempt to substitute SMP alternatives once at boot. + snd-ad1816a= [HW,ALSA] snd-ad1848= [HW,ALSA] Index: linux/arch/i386/kernel/alternative.c =================================================================== --- linux.orig/arch/i386/kernel/alternative.c +++ linux/arch/i386/kernel/alternative.c @@ -5,6 +5,7 @@ #include #include +static int noreplace_smp = 0; static int smp_alt_once = 0; static int debug_alternative = 0; @@ -13,15 +14,23 @@ static int __init bootonly(char *str) smp_alt_once = 1; return 1; } +__setup("smp-alt-boot", bootonly); + static int __init debug_alt(char *str) { debug_alternative = 1; return 1; } - -__setup("smp-alt-boot", bootonly); __setup("debug-alternative", debug_alt); +static int __init setup_noreplace_smp(char *str) +{ + noreplace_smp = 1; + return 1; +} +__setup("noreplace-smp", setup_noreplace_smp); + + #define DPRINTK(fmt, args...) if (debug_alternative) \ printk(KERN_DEBUG fmt, args) @@ -185,6 +194,9 @@ static void alternatives_smp_unlock(u8 * { u8 **ptr; + if (noreplace_smp) + return; + for (ptr = start; ptr < end; ptr++) { if (*ptr < text) continue; @@ -219,6 +231,9 @@ void alternatives_smp_module_add(struct struct smp_alt_module *smp; unsigned long flags; + if (noreplace_smp) + return; + if (smp_alt_once) { if (boot_cpu_has(X86_FEATURE_UP)) alternatives_smp_unlock(locks, locks_end, @@ -253,7 +268,7 @@ void alternatives_smp_module_del(struct struct smp_alt_module *item; unsigned long flags; - if (smp_alt_once) + if (smp_alt_once || noreplace_smp) return; spin_lock_irqsave(&smp_alt, flags); @@ -284,7 +299,7 @@ void alternatives_smp_switch(int smp) return; #endif - if (smp_alt_once) + if (noreplace_smp || smp_alt_once) return; BUG_ON(!smp && (num_online_cpus() > 1));