96 lines
3.9 KiB
Plaintext
96 lines
3.9 KiB
Plaintext
|
Last reviewed: 06/02/2009
|
||
|
|
|
||
|
|
HP iLO2 NMI Watchdog Driver
|
||
|
|
NMI sourcing for iLO2 based ProLiant Servers
|
||
|
|
Documentation and Driver by
|
||
|
|
Thomas Mingarelli <thomas.mingarelli@hp.com>
|
||
|
|
|
||
|
|
The HP iLO2 NMI Watchdog driver is a kernel module that provides basic
|
||
|
|
watchdog functionality and the added benefit of NMI sourcing. Both the
|
||
|
|
watchdog functionality and the NMI sourcing capability need to be enabled
|
||
|
|
by the user. Remember that the two modes are not dependent on one another.
|
||
|
|
A user can have the NMI sourcing without the watchdog timer and vice-versa.
|
||
|
|
|
||
|
|
Watchdog functionality is enabled like any other common watchdog driver. That
|
||
|
|
is, an application needs to be started that kicks off the watchdog timer. A
|
||
|
|
basic application exists in the Documentation/watchdog/src directory called
|
||
|
|
watchdog-test.c. Simply compile the C file and kick it off. If the system
|
||
|
|
gets into a bad state and hangs, the HP ProLiant iLO 2 timer register will
|
||
|
|
not be updated in a timely fashion and a hardware system reset (also known as
|
||
|
|
an Automatic Server Recovery (ASR)) event will occur.
|
||
|
|
|
||
|
|
The hpwdt driver also has four (4) module parameters. They are the following:
|
||
|
|
|
||
|
|
soft_margin - allows the user to set the watchdog timer value
|
||
|
|
allow_kdump - allows the user to save off a kernel dump image after an NMI
|
||
|
|
nowayout - basic watchdog parameter that does not allow the timer to
|
||
|
|
be restarted or an impending ASR to be escaped.
|
||
|
|
priority - determines whether or not the hpwdt driver is first on the
|
||
|
|
die_notify list to handle NMIs or last. The default value
|
||
|
|
for this module parameter is 0 or LAST. If the user wants to
|
||
|
|
enable NMI sourcing then reload the hpwdt driver with
|
||
|
|
priority=1 (and boot with nmi_watchdog=0).
|
||
|
|
|
||
|
|
NOTE: More information about watchdog drivers in general, including the ioctl
|
||
|
|
interface to /dev/watchdog can be found in
|
||
|
|
Documentation/watchdog/watchdog-api.txt and Documentation/IPMI.txt.
|
||
|
|
|
||
|
|
The priority parameter was introduced due to other kernel software that relied
|
||
|
|
on handling NMIs (like oprofile). Keeping hpwdt's priority at 0 (or LAST)
|
||
|
|
enables the users of NMIs for non critical events to be work as expected.
|
||
|
|
|
||
|
|
The NMI sourcing capability is disabled by default due to the inability to
|
||
|
|
distinguish between "NMI Watchdog Ticks" and "HW generated NMI events" in the
|
||
|
|
Linux kernel. What this means is that the hpwdt nmi handler code is called
|
||
|
|
each time the NMI signal fires off. This could amount to several thousands of
|
||
|
|
NMIs in a matter of seconds. If a user sees the Linux kernel's "dazed and
|
||
|
|
confused" message in the logs or if the system gets into a hung state, then
|
||
|
|
the hpwdt driver can be reloaded with the "priority" module parameter set
|
||
|
|
(priority=1).
|
||
|
|
|
||
|
|
1. If the kernel has not been booted with nmi_watchdog turned off then
|
||
|
|
edit /boot/grub/menu.lst and place the nmi_watchdog=0 at the end of the
|
||
|
|
currently booting kernel line.
|
||
|
|
2. reboot the sever
|
||
|
|
3. Once the system comes up perform a rmmod hpwdt
|
||
|
|
4. insmod /lib/modules/`uname -r`/kernel/drivers/char/watchdog/hpwdt.ko priority=1
|
||
|
|
|
||
|
|
Now, the hpwdt can successfully receive and source the NMI and provide a log
|
||
|
|
message that details the reason for the NMI (as determined by the HP BIOS).
|
||
|
|
|
||
|
|
Below is a list of NMIs the HP BIOS understands along with the associated
|
||
|
|
code (reason):
|
||
|
|
|
||
|
|
No source found 00h
|
||
|
|
|
||
|
|
Uncorrectable Memory Error 01h
|
||
|
|
|
||
|
|
ASR NMI 1Bh
|
||
|
|
|
||
|
|
PCI Parity Error 20h
|
||
|
|
|
||
|
|
NMI Button Press 27h
|
||
|
|
|
||
|
|
SB_BUS_NMI 28h
|
||
|
|
|
||
|
|
ILO Doorbell NMI 29h
|
||
|
|
|
||
|
|
ILO IOP NMI 2Ah
|
||
|
|
|
||
|
|
ILO Watchdog NMI 2Bh
|
||
|
|
|
||
|
|
Proc Throt NMI 2Ch
|
||
|
|
|
||
|
|
Front Side Bus NMI 2Dh
|
||
|
|
|
||
|
|
PCI Express Error 2Fh
|
||
|
|
|
||
|
|
DMA controller NMI 30h
|
||
|
|
|
||
|
|
Hypertransport/CSI Error 31h
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
-- Tom Mingarelli
|
||
|
|
(thomas.mingarelli@hp.com)
|