From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264514AbTDYVis (ORCPT ); Fri, 25 Apr 2003 17:38:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264521AbTDYVis (ORCPT ); Fri, 25 Apr 2003 17:38:48 -0400 Received: from palrel11.hp.com ([156.153.255.246]:52661 "EHLO palrel11.hp.com") by vger.kernel.org with ESMTP id S264514AbTDYVio (ORCPT ); Fri, 25 Apr 2003 17:38:44 -0400 From: David Mosberger MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <16041.44478.599115.696527@napali.hpl.hp.com> Date: Fri, 25 Apr 2003 14:50:54 -0700 To: "H. Peter Anvin" Cc: davidm@hpl.hp.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] i386 vsyscall DSO implementation In-Reply-To: <3EA9A6AF.7060409@zytor.com> References: <3EA8942D.4050201@pobox.com> <200304250210.h3P2AoU12348@magilla.sf.frob.com> <16041.24730.267207.671647@napali.hpl.hp.com> <16041.42469.529671.272810@napali.hpl.hp.com> <3EA9A6AF.7060409@zytor.com> X-Mailer: VM 7.07 under Emacs 21.2.1 Reply-To: davidm@hpl.hp.com X-URL: http://www.hpl.hp.com/personal/David_Mosberger/ Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org >>>>> On Fri, 25 Apr 2003 14:20:47 -0700, "H. Peter Anvin" said: hpa> David Mosberger wrote: >> >> To complete the picture, it would be nice if the kernel ELF >> >> images were mappable files (either in /sysfs or /proc) and >> would >> show up in /proc/PID/maps. That way, a distributed >> application >> such as a remote debugger could gain access to the >> kernel unwind >> tables on a remote machine (assuming you have a >> remote >> filesystem). hpa> How about /boot? >> You mean a regular file? I'm not sure whether this could be >> made to work. The /proc/PID/maps entry (really: the vm_area for >> the kernel ELF images) would have to be created by the kernel, at >> a time when no real filesystem is available. Also, since the >> kernel needs to store the data in kernel-memory anyhow, I don't >> think there is much point in storing it on disk as well. hpa> Perhaps I misunderstood the statement. With "kernel ELF hpa> images" above, I am now gathering you're talking about only the hpa> segments exported to userspace (i.e. vsyscall code), not the hpa> kernel itself, which was my original reading of that statement. Sort of. I used the term "kernel ELF images" to refer to kernel code that is shared with the user. I thought that even on x86 this code is pinned in memory, but perhaps I misunderstood. Anyhow, it seems to me that using a special filesystem would be more suitable, as otherwise you get into bootstrap problems etc. --david