Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753607Ab3EFNKG (ORCPT ); Mon, 6 May 2013 09:10:06 -0400 Received: from e06smtp13.uk.ibm.com ([195.75.94.109]:59409 "EHLO e06smtp13.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752863Ab3EFNKE (ORCPT ); Mon, 6 May 2013 09:10:04 -0400 From: Michael Holzheu To: Vivek Goyal Cc: linux-kernel@vger.kernel.org, kexec@lists.infradead.org, Jan Willeke , Heiko Carstens , Martin Schwidefsky , Michael Holzheu Subject: [PATCH 0/4] kdump: Allow ELF header creation in new kernel Date: Mon, 6 May 2013 15:09:55 +0200 Message-Id: <1367845799-29125-1-git-send-email-holzheu@linux.vnet.ibm.com> X-Mailer: git-send-email 1.8.1.6 X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13050613-2966-0000-0000-000007859E4A Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2585 Lines: 64 Hello Vivek, For s390 we want to use /proc/vmcore for our SCSI stand-alone dump (zfcpdump). We have support where the first HSA_SIZE bytes are saved into a hypervisor owned memory area (HSA) before the kdump kernel is booted. When the kdump kernel starts, it is restricted to use only HSA_SIZE bytes. The advantages of this mechanism are: * No crashkernel memory has to be defined in the old kernel. * Early boot problems (before kexec_load has been done) can be dumped * Non-Linux systems can be dumped. We modify the s390 copy_oldmem_page() function to read from the HSA memory if memory below HSA_SIZE bytes is requested. Since we cannot use the kexec tool to load the kernel in this scenario, we have to build the ELF header in the 2nd (kdump/new) kernel. So with the following patch set we would like to introduce the new function that the ELF header for /proc/vmcore can be created in the 2nd kernel memory. The following steps are done during zfcpdump execution: 1. Production system crashes 2. User boots a SCSI disk that has been prepared with the zfcpdump tool 3. Hypervisor saves CPU state of boot CPU and HSA_SIZE bytes of memory into HSA 4. Boot loader loads kernel into low memory area 5. Kernel boots and uses only HSA_SIZE bytes of memory 6. Kernel saves registers of non-boot CPUs 7. Kernel does memory detection for dump memory map 8. Kernel creates ELF header for /proc/vmcore 9. /proc/vmcore uses this header for initialization 10. The zfcpdump user space reads /proc/vmcore to write dump to SCSI disk - copy_oldmem_page() copies from HSA for memory below HSA_SIZE - copy_oldmem_page() copies from real memory for memory above HSA_SIZE Jan Willeke (1): s390/kdump: Use ELFCORE_ADDR_NEWMEM for zfcpdump Michael Holzheu (3): kdump: Introduce ELFCORE_ADDR_NEWMEM s390/kdump: Use ELFCORE_ADDR_NEWMEM for kdump kdump: Merge set_vmcore_list_offsets_elf64/elf32/newmem arch/s390/Kconfig | 3 +- arch/s390/include/asm/sclp.h | 1 + arch/s390/kernel/crash_dump.c | 103 +++++++++++++++++++++++++++--------------- arch/s390/kernel/setup.c | 2 +- drivers/s390/char/zcore.c | 6 +-- fs/proc/vmcore.c | 89 ++++++++++++++++++++++-------------- include/linux/crash_dump.h | 4 +- 7 files changed, 131 insertions(+), 77 deletions(-) -- 1.8.1.6 -- 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/