From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from vms173013pub.verizon.net ([206.46.173.13]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1aTAMp-0002ij-DJ for kexec@lists.infradead.org; Tue, 09 Feb 2016 15:38:15 +0000 Received: from serve.minyard.net ([173.57.176.17]) by vms173013.mailsrvcs.net (Oracle Communications Messaging Server 7.0.5.32.0 64bit (built Jul 16 2014)) with ESMTPA id <0O2A00MDSE2MVY60@vms173013.mailsrvcs.net> for kexec@lists.infradead.org; Tue, 09 Feb 2016 09:37:34 -0600 (CST) Received: from [IPv6:2001:470:b8f6:1b:e553:a7f5:748e:1b1d] (unknown [IPv6:2001:470:b8f6:1b:e553:a7f5:748e:1b1d]) by serve.minyard.net (Postfix) with ESMTPSA id 3C00FC2C for ; Tue, 9 Feb 2016 09:37:34 -0600 (CST) From: Corey Minyard Subject: Handling an elf kernel dump with a randomized base Message-id: <56BA07BD.3090009@acm.org> Date: Tue, 09 Feb 2016 09:37:33 -0600 MIME-version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: minyard@acm.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Kexec Mailing List I have been working on getting kernels on different architectures with randomized base operational. One problem I've run into is that kernel dumps taken this way are not debuggable with gdb, the symbols are, of course, all in the wrong places. The way gdb handles relocation is to add an AT_ENTRY value in an auxv note. It holds the relocated start address and gdb uses that to figure out the offsets. This is easy enough to add if you have the information, I'm wondering the best way to do this looking at getting it into the mainstream kernel and the crash dump tools. There is some handling of this on x86_64 with KERNELOFFSET, but it doesn't work for gdb. I can think of two ways to add this: * Add a vmcoreinfo value with the entry point and have the extraction tool create the elf note. * Put the entry point in sysfs and have kexec add the note like it does for vmcoreinfo. I'd like to avoid any solution that requires putting vmlinux or any other large file on the target system, as this is not always possible for small embedded systems. Thanks, -corey _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec