mirror of
https://github.com/torvalds/linux.git
synced 2024-12-25 04:11:49 +00:00
718d50ec78
Make refs to selftests files valid including: - watchdog-test.c - dnotify_test.c Signed-off-by: Tom Saeger <tom.saeger@oracle.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
98 lines
3.8 KiB
Plaintext
98 lines
3.8 KiB
Plaintext
Last reviewed: 05/20/2016
|
|
|
|
HPE iLO NMI Watchdog Driver
|
|
NMI sourcing for iLO based ProLiant Servers
|
|
Documentation and Driver by
|
|
Thomas Mingarelli
|
|
|
|
The HPE iLO 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.
|
|
All references to iLO in this document imply it also works on iLO2 and all
|
|
subsequent generations.
|
|
|
|
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 tools/testing/selftests/watchdog/ named
|
|
watchdog-test.c. Simply compile the C file and kick it off. If the system
|
|
gets into a bad state and hangs, the HPE ProLiant iLO 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 three (3) module parameters. They are the following:
|
|
|
|
soft_margin - allows the user to set the watchdog timer value.
|
|
Default value is 30 seconds.
|
|
allow_kdump - allows the user to save off a kernel dump image after an NMI.
|
|
Default value is 1/ON
|
|
nowayout - basic watchdog parameter that does not allow the timer to
|
|
be restarted or an impending ASR to be escaped.
|
|
Default value is set when compiling the kernel. If it is set
|
|
to "Y", then there is no way of disabling the watchdog once
|
|
it has been started.
|
|
|
|
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 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.
|
|
|
|
1. If the kernel has not been booted with nmi_watchdog turned off then
|
|
edit and place the nmi_watchdog=0 at the end of the currently booting
|
|
kernel line. Depending on your Linux distribution and platform setup:
|
|
For non-UEFI systems
|
|
/boot/grub/grub.conf or
|
|
/boot/grub/menu.lst
|
|
For UEFI systems
|
|
/boot/efi/EFI/distroname/grub.conf or
|
|
/boot/efi/efi/distroname/elilo.conf
|
|
2. reboot the sever
|
|
3. Once the system comes up perform a modprobe -r hpwdt
|
|
4. modprobe /lib/modules/`uname -r`/kernel/drivers/watchdog/hpwdt.ko
|
|
|
|
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 HPE BIOS).
|
|
|
|
Below is a list of NMIs the HPE 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
|