From owner-freebsd-hackers@FreeBSD.ORG Tue Aug 10 16:46:54 2004 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id A1A7316A4CE for ; Tue, 10 Aug 2004 16:46:54 +0000 (GMT) Received: from cydem.org (S0106000103ce4c9c.ed.shawcable.net [68.149.254.167]) by mx1.FreeBSD.org (Postfix) with ESMTP id 575B743D49 for ; Tue, 10 Aug 2004 16:46:54 +0000 (GMT) (envelope-from soralx@cydem.org) Received: from [68.149.254.171] (S01060020ed3972ba.ed.shawcable.net [68.149.254.171]) by cydem.org (Postfix/FreeBSD) with ESMTP id 2E7B538258; Tue, 10 Aug 2004 10:46:54 -0600 (MDT) From: To: freebsd-hackers@freebsd.org Date: Tue, 10 Aug 2004 10:46:50 -0600 User-Agent: KMail/1.6.2 References: In-Reply-To: MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <200408101046.50543.soralx@cydem.org> cc: breath@unix.net Subject: Re: Reboots after "OR AL,1 MOV CR0, EAX" on some computers. X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 10 Aug 2004 16:46:54 -0000 > good free environment for initialization and further running. Shortly: ON > SOME COMPUTERS (MAYBE CPUS) I GET REBOOTING JUST ON 'JMP' INSTRUCTION > AFTER PE BIT IS ENABLED. I've got no reboots on all i386, i486, i586 > computers that I tryed to boot from. I have a Pentium III Celeron > (Coppermine) 900MHz - no reboots. Also tested on some Pentium II 400MHz - > no reboots. But on other side Pentium IV (don't remember speed) gave me a > reboot. And other computer I was not able to see processor model (maybe > PentiumIV !?) gave me a reboot too. Using endless loop stop points I > figured out that reboot is before any instruction pointed by 'protected' > label and that reboot happens after setting the PE bit. I've tested the code on a Dual-CPU P-166 - the system always goes into cold reboot. I first thought that SMP systems need some special procedure to switch to protected mode (the fact that all Pentium IV CPUs have second logical processor helps the idea), but then I tested it on Athlon XP system - reboots also. I'll play with it later. Maybe somebody at freebsd-hackers know the answer? Timestamp: 0x4118F317 [SorAlx] http://cydem.org.ua/ ridin' VN1500-B2