linux/arch/powerpc
Stewart Smith 774fea1a38 powerpc/powernv: Read OPAL error log and export it through sysfs
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>
2014-03-07 16:19:00 +11:00
..
boot powerpc: Delete old PrPMC 280/2800 support 2014-03-07 15:54:48 +11:00
configs powerpc: Delete old PrPMC 280/2800 support 2014-03-07 15:54:48 +11:00
crypto powerpc: Fix compile of sha1-powerpc-asm.S on 32-bit 2013-03-05 16:56:26 +11:00
include powerpc/powernv: Read OPAL error log and export it through sysfs 2014-03-07 16:19:00 +11:00
kernel powerpc/pseries: Update dynamic cache nodes for suspend/resume operation 2014-03-07 15:54:49 +11:00
kvm Second batch of KVM updates. Some minor x86 fixes, 2014-01-31 08:37:32 -08:00
lib selftests/powerpc: Import Anton's memcpy / copy_tofrom_user tests 2014-03-07 15:53:12 +11:00
math-emu powerpc: fix e500 SPE float SIGFPE generation 2014-01-07 18:43:42 -06:00
mm powerpc/book3e: Fix check for linear mapping in TLB miss handler 2014-03-07 15:54:51 +11:00
net bpf: do not use reciprocal divide 2014-01-15 17:02:08 -08:00
oprofile powerpc: Delete non-required instances of include <linux/init.h> 2014-01-15 13:46:44 +11:00
perf powerpc/perf: Configure BHRB filter before enabling PMU interrupts 2014-02-11 11:24:50 +11:00
platforms powerpc/powernv: Read OPAL error log and export it through sysfs 2014-03-07 16:19:00 +11:00
sysdev powerpc: Fix build failure in sysdev/mpic.c for MPIC_WEIRD=y 2014-02-11 11:24:45 +11:00
xmon powerpc: Fix xmon disassembler for little-endian 2014-03-07 15:50:12 +11:00
Kconfig powerpc: Add "force config cmd line" Kconfig option 2014-03-07 15:54:50 +11:00
Kconfig.debug Merge branch 'kconfig-diet' from Dave Hansen 2013-07-04 11:25:51 -07:00
Makefile powerpc: Fix error when cross building TAGS & cscope 2013-11-25 11:49:11 +11:00
relocs_check.pl Fix warning typo "CONFIG_RELCOATABLE" 2013-05-29 15:11:30 +02:00