mirror of https://gitee.com/openkylin/linux.git
774fea1a38
Based on a patch by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> This patch adds support to read error logs from OPAL and export them to userspace through a sysfs interface. We export each log entry as a directory in /sys/firmware/opal/elog/ Currently, OPAL will buffer up to 128 error log records, we don't need to have any knowledge of this limit on the Linux side as that is actually largely transparent to us. Each error log entry has the following files: id, type, acknowledge, raw. Currently we just export the raw binary error log in the 'raw' attribute. In a future patch, we may parse more of the error log to make it a bit easier for userspace (e.g. to be able to display a brief summary in petitboot without having to have a full parser). If we have >128 logs from OPAL, we'll only be notified of 128 until userspace starts acknowledging them. This limitation may be lifted in the future and with this patch, that should "just work" from the linux side. A userspace daemon should: - wait for error log entries using normal mechanisms (we announce creation) - read error log entry - save error log entry safely to disk - acknowledge the error log entry - rinse, repeat. On the Linux side, we read the error log when we're notified of it. This possibly isn't ideal as it would be better to only read them on-demand. However, this doesn't really work with current OPAL interface, so we read the error log immediately when notified at the moment. I've tested this pretty extensively and am rather confident that the linux side of things works rather well. There is currently an issue with the service processor side of things for >128 error logs though. Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> |
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