Re: [PATCH 00/18] Add FADump support on PowerNV platform
From: Hari Bathini <hbathini@linux.ibm.com>
Date: 2019-02-28 05:03:50
On 27/02/19 9:07 AM, Daniel Axtens wrote:
Hi Hari,
Hi Daniel,
quoted
Firmware-Assisted Dump (FADump) is currently supported only on pseries platform. This patch series adds support for powernv platform too. The first and third patches refactor the FADump code to make use of common code across multiple platforms. The fifth patch adds basic FADump support for powernv platform. Patches seven & eight honour reserved-ranges DT node while reserving/releasing memory used by FADump. The next patch processes CPU state data provided by firmware to create and append core notes to the ELF core file. The tenth patch adds support for preserving crash data for subsequent boots (useful in cases like petitboot). Patch twelve provides support to export opalcore. This is to make debugging of failures in OPAL code easier. The subsequent patch ensures vmcore processing is skipped when only OPAL core is exported by f/w. The next patch provides option to release the kernel memory used to export opalcore. Patch seventeen adds backup area (an area populated before crash and used in the capture kernel to setup vmcore file robustly) support on PowerNV platform. The remaining patches update Firmware-Assisted Dump documentation appropriately. Note that the quantam of increase in robustness due to patch seventeen may not be worth breaking backward compatibility for older kernel versions. Would like to hear thoughts from others on it. The patch series is tested with the latest firmware plus the below skiboot changes for MPIPL support: https://patchwork.ozlabs.org/project/skiboot/list/?series=78497 ("MPIPL support")If I want to test this, is there some userspace tooling that will extract a fadump from a rebooted system and allow me to examine it as I would with a kdump (e.g. with crash)? I did look at Documentation/powerpc/firmware-assisted-dump.txt but it seems to only cover the kernel layer.
This patches export two dump files: /proc/vmcore (kernel), /proc/opalcore (OPAL). If you are only interested in kernel dump, then passing fadump=on to the kernel and enabling/starting kdump-tools/kdump service, shipped with distro, would ensure dump is captured to /var/crash dir and rebooted but please be aware that the script would not copy /proc/opalcore to disk yet. Need to update scripts once this changes make it upstream.. Thanks Hari