Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760711AbZAHPFS (ORCPT ); Thu, 8 Jan 2009 10:05:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751778AbZAHPE6 (ORCPT ); Thu, 8 Jan 2009 10:04:58 -0500 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:53045 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751132AbZAHPE5 (ORCPT ); Thu, 8 Jan 2009 10:04:57 -0500 Date: Thu, 8 Jan 2009 15:04:48 +0000 From: Alan Cox To: Peter Zijlstra Cc: Jiri Kosina , Adam Osuchowski , linux-kernel@vger.kernel.org, Ingo Molnar , Nick Piggin Subject: Re: Is 386 processor still supported? Message-ID: <20090108150448.2393aeb0@lxorguk.ukuu.org.uk> In-Reply-To: <1231424833.11687.452.camel@twins> References: <20090108120338.6b8b4567@zonk.pl> <1231424025.11687.447.camel@twins> <1231424833.11687.452.camel@twins> X-Mailer: Claws Mail 3.5.0 (GTK+ 2.12.12; x86_64-redhat-linux-gnu) Organization: Red Hat UK Cyf., Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, Y Deyrnas Gyfunol. Cofrestrwyd yng Nghymru a Lloegr o'r rhif cofrestru 3798903 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1219 Lines: 29 > > Hmm. Where in Kconfig is SMP for M386 not allowed? > > Dunno, kconfig is too much of a jungle for a simple person like me ;-) > > But afaik i386 (and possibly i486) don't support nearly enough for a > modern SMP system. > > Alan used to have i486-smp I think, one of the very few ever made. The first systems that supported the Intel MP standard are 486 based with external APIC. The prior systems used various proprietary MP interfaces from the simple stuff in the Compaq (which Linux doesn't support as Compaq refused to allow Thomas Radke to contribute it) to the fairly extreme end of things with the Sequent boxes. In addition our FPU emulation and some of our handling for x86 processors where we have to do the WP bit in software is also not SMP safe. So our minimal spec for SMP is probably 486DX + external Intel APIC. In practice I doubt there is a single Intel APIC type 486 SMP box on the planet running Linux (or quite possibly running at all) Alan -- 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/