From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 673 invoked by alias); 22 Feb 2010 19:52:26 -0000 Received: (qmail 639 invoked by uid 22791); 22 Feb 2010 19:52:23 -0000 X-SWARE-Spam-Status: No, hits=-2.5 required=5.0 tests=AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from sibelius.xs4all.nl (HELO glazunov.sibelius.xs4all.nl) (83.163.83.176) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Mon, 22 Feb 2010 19:52:14 +0000 Received: from glazunov.sibelius.xs4all.nl (kettenis@localhost [127.0.0.1]) by glazunov.sibelius.xs4all.nl (8.14.3/8.14.3) with ESMTP id o1MJoqLQ002132; Mon, 22 Feb 2010 20:50:52 +0100 (CET) Received: (from kettenis@localhost) by glazunov.sibelius.xs4all.nl (8.14.3/8.14.3/Submit) id o1MJoomn007989; Mon, 22 Feb 2010 20:50:50 +0100 (CET) Date: Mon, 22 Feb 2010 19:52:00 -0000 Message-Id: <201002221950.o1MJoomn007989@glazunov.sibelius.xs4all.nl> From: Mark Kettenis To: dan@codesourcery.com CC: hjl.tools@gmail.com, gdb-patches@sourceware.org In-reply-to: <20100222170303.GG9493@caradoc.them.org> (message from Daniel Jacobowitz on Mon, 22 Feb 2010 12:03:03 -0500) Subject: Re: PATCH: Enable x86 XML target descriptions References: <20100218054312.GA9022@lucon.org> <20100218153402.GA27929@lucon.org> <20100218230135.GA17916@intel.com> <201002221342.o1MDgSZA029705@glazunov.sibelius.xs4all.nl> <20100222144141.GA30100@caradoc.them.org> <6dc9ffc81002220734i15bd1279mb54cb0b64a37f3dc@mail.gmail.com> <20100222155243.GC30100@caradoc.them.org> <6dc9ffc81002220757v5e9b48bdnba56a260f0f3c0a8@mail.gmail.com> <20100222161040.GD30100@caradoc.them.org> <201002221656.o1MGuw5q009795@glazunov.sibelius.xs4all.nl> <20100222170303.GG9493@caradoc.them.org> Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2010-02/txt/msg00552.txt.bz2 > Date: Mon, 22 Feb 2010 12:03:03 -0500 > From: Daniel Jacobowitz > > On Mon, Feb 22, 2010 at 05:56:58PM +0100, Mark Kettenis wrote: > > I've looked at the Linux kernel sources for the kernel on my > > workstation (2.6.27 in its OpenSUSE incarnation), and the only way to > > distinguish between a 32-bit and a 64-bit process seems to be to > > attempt to write one of the debug address registers with a value > > that's larger than 0xffffffff. If that fails, you have a 32-bit > > process, otherwise it's a 64-bit process. > > Yuck :-( But I didn't see anything else either. Indeed. > Is there an eflags bit for this? Even if so, IIRC, we may not want to > use it; it's possible to run 32-bit code in a 64-bit process and some > overly clever programs may do so. Nope, there is no %eflags/%rflags bit for this. Not quite sure what running 32-bit code in a 64-bit process actually means. But I'd guess you want the 64-bit view on the registers in that case. Anyway, I think it's probably best if HJ leaves this bit out of this diff for now. We can revisit the issue when AVX support is introduced.