From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from e06smtp16.uk.ibm.com ([195.75.94.112]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UgEID-0000W1-PM for kexec@lists.infradead.org; Sat, 25 May 2013 13:13:54 +0000 Received: from /spool/local by e06smtp16.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Sat, 25 May 2013 14:09:05 +0100 Received: from b06cxnps3074.portsmouth.uk.ibm.com (d06relay09.portsmouth.uk.ibm.com [9.149.109.194]) by d06dlp01.portsmouth.uk.ibm.com (Postfix) with ESMTP id EB53A17D8025 for ; Sat, 25 May 2013 14:14:40 +0100 (BST) Received: from d06av02.portsmouth.uk.ibm.com (d06av02.portsmouth.uk.ibm.com [9.149.37.228]) by b06cxnps3074.portsmouth.uk.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r4PDDI3d52822066 for ; Sat, 25 May 2013 13:13:18 GMT Received: from d06av02.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av02.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id r4PDDRTa001038 for ; Sat, 25 May 2013 07:13:28 -0600 Date: Sat, 25 May 2013 15:13:24 +0200 From: Michael Holzheu Subject: Re: [PATCH 0/2] kdump/mmap: Fix mmap of /proc/vmcore for s390 Message-ID: <20130525151324.637d6b70@holzheu> In-Reply-To: <20130524170507.GG18218@redhat.com> References: <1369400889-11064-1-git-send-email-holzheu@linux.vnet.ibm.com> <20130524143644.GD18218@redhat.com> <20130524170626.2ac06efe@holzheu> <20130524152849.GF18218@redhat.com> <20130524184653.52d75b5f@holzheu> <20130524170507.GG18218@redhat.com> Mime-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=twosheds.infradead.org@lists.infradead.org To: Vivek Goyal Cc: Heiko Carstens , kexec@lists.infradead.org, Jan Willeke , linux-kernel@vger.kernel.org, HATAYAMA Daisuke , "Eric W. Biederman" , Martin Schwidefsky , Andrew Morton On Fri, 24 May 2013 13:05:07 -0400 Vivek Goyal wrote: > On Fri, May 24, 2013 at 06:46:53PM +0200, Michael Holzheu wrote: > > On Fri, 24 May 2013 11:28:49 -0400 > > Vivek Goyal wrote: > > > > > On Fri, May 24, 2013 at 05:06:26PM +0200, Michael Holzheu wrote: > > > > [snip] > > > > > As /proc/vmcore is the most used and useful interface, I prefer > > > that we swap memory and put that info in elf headers. > > > For /dev/oldme, I don't mind if we leave it as it is. If somebody > > > really cares, then I guess we need to write a new command line > > > option which /dev/mem can parse and which tells it about swaps so > > > that /dev/oldmem can map things correctly. (This is better than > > > hardcoding things). > > > > Besides of the potential /dev/oldmem issue, I still do not > > understand the option of doing the swap in the elf header. Looks > > like I missed here a fundamental design point of kdump :( > > > > Is that done by specifying different virtual and physical addresses > > in the ELF header? > > Nope. We keep the virtual to physical address mapping same. We just > modify the p_offset in PT_LOAD elf header to represent where actually > the memory is present physically. And when /proc/vmcore reads the > data, it reads it from p_offset. > > IOW, p_offset and p_paddr will be different for swapped memory but > should be same for memory which has not been swapped. Hello Vivek, Ok, now I got it :) It worked for me by specifying a PT_LOAD with: phdr->p_offset = OLDMEM_BASE; phdr->p_vaddr = phdr->p_paddr = 0; phdr->p_filesz = phdr->p_memsz = OLDMEM_SIZE; Best Regards, Michael _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec