--- /dev/null
+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 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)
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/irq.h>
+#include <linux/nmi.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/mm.h>
#define PCI_BIOS32_PARAGRAPH_LEN 16
#define PCI_ROM_BASE1 0x000F0000
#define ROM_SIZE 0x10000
-#define HPWDT_VERSION "1.01"
+#define HPWDT_VERSION "1.1.1"
struct bios32_service_dir {
u32 signature;
static char expect_release;
static unsigned long hpwdt_is_open;
static unsigned int allow_kdump;
+static int hpwdt_nmi_sourcing;
static void __iomem *pci_mem_addr; /* the PCI-memory address */
static unsigned long __iomem *hpwdt_timer_reg;
if (ulReason != DIE_NMI && ulReason != DIE_NMI_IPI)
return NOTIFY_OK;
- spin_lock_irqsave(&rom_lock, rom_pl);
- if (!die_nmi_called)
- asminline_call(&cmn_regs, cru_rom_addr);
- die_nmi_called = 1;
- spin_unlock_irqrestore(&rom_lock, rom_pl);
- if (cmn_regs.u1.ral == 0) {
- printk(KERN_WARNING "hpwdt: An NMI occurred, "
- "but unable to determine source.\n");
- } else {
- if (allow_kdump)
- hpwdt_stop();
- panic("An NMI occurred, please see the Integrated "
- "Management Log for details.\n");
+ if (hpwdt_nmi_sourcing) {
+ spin_lock_irqsave(&rom_lock, rom_pl);
+ if (!die_nmi_called)
+ asminline_call(&cmn_regs, cru_rom_addr);
+ die_nmi_called = 1;
+ spin_unlock_irqrestore(&rom_lock, rom_pl);
+ if (cmn_regs.u1.ral == 0) {
+ printk(KERN_WARNING "hpwdt: An NMI occurred, "
+ "but unable to determine source.\n");
+ } else {
+ if (allow_kdump)
+ hpwdt_stop();
+ panic("An NMI occurred, please see the Integrated "
+ "Management Log for details.\n");
+ }
}
-
return NOTIFY_OK;
}
* Init & Exit
*/
+#ifdef ARCH_HAS_NMI_WATCHDOG
+static void __devinit hpwdt_check_nmi_sourcing(struct pci_dev *dev)
+{
+ /*
+ * If nmi_watchdog is turned off then we can turn on
+ * our nmi sourcing capability.
+ */
+ if (!nmi_watchdog_active())
+ hpwdt_nmi_sourcing = 1;
+ else
+ dev_warn(&dev->dev, "NMI sourcing is disabled. To enable this "
+ "functionality you must reboot with nmi_watchdog=0.\n");
+}
+#else
+static void __devinit hpwdt_check_nmi_sourcing(struct pci_dev *dev)
+{
+ dev_warn(&dev->dev, "NMI sourcing is disabled. "
+ "Your kernel does not support a NMI Watchdog.\n");
+}
+#endif
+
static int __devinit hpwdt_init_one(struct pci_dev *dev,
const struct pci_device_id *ent)
{
int retval;
/*
+ * Check if we can do NMI sourcing or not
+ */
+ hpwdt_check_nmi_sourcing(dev);
+
+ /*
* First let's find out if we are on an iLO2 server. We will
* not run on a legacy ASM box.
* So we only support the G5 ProLiant servers and higher.
git://ftp.safe.ca / safe / jmp / linux-2.6 / commitdiff