From 47bece87b14b866872b52ff04d469832e4936756 Mon Sep 17 00:00:00 2001 From: Thomas Mingarelli Date: Thu, 4 Jun 2009 19:50:45 +0000 Subject: [WATCHDOG] hpwdt: Add NMI sourcing Add NMI sourcing functionality (Can only be active if nmi_watchdog is inactive). Signed-off-by: Thomas Mingarelli Signed-off-by: Wim Van Sebroeck --- Documentation/watchdog/hpwdt.txt | 84 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 84 insertions(+) create mode 100644 Documentation/watchdog/hpwdt.txt (limited to 'Documentation/watchdog') diff --git a/Documentation/watchdog/hpwdt.txt b/Documentation/watchdog/hpwdt.txt new file mode 100644 index 00000000000..127839e5304 --- /dev/null +++ b/Documentation/watchdog/hpwdt.txt @@ -0,0 +1,84 @@ +Last reviewed: 06/02/2009 + + HP iLO2 NMI Watchdog Driver + NMI sourcing for iLO2 based ProLiant Servers + Documentation and Driver by + Thomas Mingarelli + + 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 dependant 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 three (3) 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. + + 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 when the driver discovers that the + nmi_watchdog is turned on (nmi_watchdog = 1). This is 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 user should reboot with nmi_watchdog=0. + + 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 + + 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) -- cgit v1.2.3 From 44df75353bc8f32e26e049284053a61d4f1047d6 Mon Sep 17 00:00:00 2001 From: Tom Mingarelli Date: Thu, 18 Jun 2009 23:28:57 +0000 Subject: [WATCHDOG] hpwdt: Add NMI priority option Add a priority option so that the user can choose if we do the NMI first or last. Signed-off-by: Thomas Mingarelli Signed-off-by: Wim Van Sebroeck --- Documentation/watchdog/hpwdt.txt | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) (limited to 'Documentation/watchdog') diff --git a/Documentation/watchdog/hpwdt.txt b/Documentation/watchdog/hpwdt.txt index 127839e5304..9c24d5ffbb0 100644 --- a/Documentation/watchdog/hpwdt.txt +++ b/Documentation/watchdog/hpwdt.txt @@ -19,30 +19,41 @@ Last reviewed: 06/02/2009 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: + 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 NMI sourcing capability is disabled when the driver discovers that the - nmi_watchdog is turned on (nmi_watchdog = 1). This is due to the inability to + 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 user should reboot with nmi_watchdog=0. + 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). -- cgit v1.2.3