Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261611AbTHYFuh (ORCPT ); Mon, 25 Aug 2003 01:50:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261637AbTHYFug (ORCPT ); Mon, 25 Aug 2003 01:50:36 -0400 Received: from mail.jlokier.co.uk ([81.29.64.88]:46980 "EHLO mail.jlokier.co.uk") by vger.kernel.org with ESMTP id S261620AbTHYFuf (ORCPT ); Mon, 25 Aug 2003 01:50:35 -0400 Date: Mon, 25 Aug 2003 06:50:28 +0100 From: Jamie Lokier To: Jakob Oestergaard , Jim Houston , linux-kernel@vger.kernel.org, jim.houston@ccur.com Subject: Re: [PATCH] Pentium Pro - sysenter - doublefault Message-ID: <20030825055028.GE20529@mail.jlokier.co.uk> References: <1061498486.3072.308.camel@new.localdomain> <20030825040514.GA20529@mail.jlokier.co.uk> <20030825041423.GB29987@unthought.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030825041423.GB29987@unthought.net> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 878 Lines: 26 Jakob Oestergaard wrote: > > Jim you can answer this as you have such a Ppro. Could you please run > > this very simple userspace program for me, and report the result? > > > > int main() { __asm__ ("sysenter"); return 0; } > > I tested on two boxes: > > Stepping 1 ppro: SIGSEGV > Stepping 7 ppro: SIGSEGV Thank you! So that means the sysenter instruction _does_ exist on the PPro and early Pentium II, but it isn't usable. It's safe so long as it is disabled, but as you found, when you enable and use it, it doesn't work as expected. (I wonder what the actual behaviour of sysenter/sysexit are on these CPUs.) -- Jamie - 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/