Some watchdog timers support the concept of a "pretimeout" which
occurs some time before the real timeout. The pretimeout can
be delivered via an interrupt or NMI and can be used to panic
the system when it occurs (so you get useful information instead
of a blind reboot).
The IPMI watchdog has had this built in, but this creates a standard
mechanism for all watchdogs and switches the IPMI driver over to it.
Signed-off-by: Corey Minyard <[email protected]>
Index: linux-2.6.16/Documentation/watchdog/watchdog-api.txt
===================================================================
--- linux-2.6.16.orig/Documentation/watchdog/watchdog-api.txt
+++ linux-2.6.16/Documentation/watchdog/watchdog-api.txt
@@ -107,7 +107,31 @@ current timeout using the GETTIMEOUT ioc
ioctl(fd, WDIOC_GETTIMEOUT, &timeout);
printf("The timeout was is %d seconds\n", timeout);
-Envinronmental monitoring:
+Pretimeouts:
+
+Some watchdog timers can be set to have a trigger go off before the
+actual time they will reset the system. This can be done with an NMI,
+interrupt, or other mechanism. This allows Linux to record useful
+information (like panic information and kernel coredumps) before it
+resets.
+
+ pretimeout = 10;
+ ioctl(fd, WDIOC_SETPRETIMEOUT, &pretimeout);
+
+Note that the pretimeout is the number of seconds before the time
+when the timeout will go off. It is not the number of seconds until
+the pretimeout. So, for instance, if you set the timeout to 60 seconds
+and the pretimeout to 10 seconds, the pretimout will go of in 50
+seconds. Setting a pretimeout to zero disables it.
+
+There is also a get function for getting the pretimeout:
+
+ ioctl(fd, WDIOC_GETPRETIMEOUT, &timeout);
+ printf("The pretimeout was is %d seconds\n", timeout);
+
+Not all watchdog drivers will support a pretimeout.
+
+Environmental monitoring:
All watchdog drivers are required return more information about the system,
some do temperature, fan and power level monitoring, some can tell you
@@ -166,6 +190,10 @@ The watchdog saw a keepalive ping since
WDIOF_SETTIMEOUT Can set/get the timeout
+The watchdog can do pretimeouts.
+
+ WDIOF_PRETIMEOUT Pretimeout (in seconds), get/set
+
For those drivers that return any bits set in the option field, the
GETSTATUS and GETBOOTSTATUS ioctls can be used to ask for the current
Index: linux-2.6.16/drivers/char/ipmi/ipmi_watchdog.c
===================================================================
--- linux-2.6.16.orig/drivers/char/ipmi/ipmi_watchdog.c
+++ linux-2.6.16/drivers/char/ipmi/ipmi_watchdog.c
@@ -122,16 +122,9 @@
#define IPMI_WDOG_SET_TIMER 0x24
#define IPMI_WDOG_GET_TIMER 0x25
-/* These are here until the real ones get into the watchdog.h interface. */
-#ifndef WDIOC_GETTIMEOUT
-#define WDIOC_GETTIMEOUT _IOW(WATCHDOG_IOCTL_BASE, 20, int)
-#endif
-#ifndef WDIOC_SET_PRETIMEOUT
-#define WDIOC_SET_PRETIMEOUT _IOW(WATCHDOG_IOCTL_BASE, 21, int)
-#endif
-#ifndef WDIOC_GET_PRETIMEOUT
-#define WDIOC_GET_PRETIMEOUT _IOW(WATCHDOG_IOCTL_BASE, 22, int)
-#endif
+/* These are here for backwards compatability for a while. */
+#define WDIOC_OLD_IPMI_SET_PRETIMEOUT _IOW(WATCHDOG_IOCTL_BASE, 21, int)
+#define WDIOC_OLD_IPMI_GET_PRETIMEOUT _IOW(WATCHDOG_IOCTL_BASE, 22, int)
static int nowayout = WATCHDOG_NOWAYOUT;
@@ -598,7 +591,8 @@ static void panic_halt_ipmi_heartbeat(vo
static struct watchdog_info ident =
{
- .options = 0, /* WDIOF_SETTIMEOUT, */
+ .options = (WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE
+ | WDIOF_PRETIMEOUT),
.firmware_version = 1,
.identity = "IPMI"
};
@@ -628,14 +622,16 @@ static int ipmi_ioctl(struct inode *inod
return -EFAULT;
return 0;
- case WDIOC_SET_PRETIMEOUT:
+ case WDIOC_OLD_IPMI_SET_PRETIMEOUT:
+ case WDIOC_SETPRETIMEOUT:
i = copy_from_user(&val, argp, sizeof(int));
if (i)
return -EFAULT;
pretimeout = val;
return ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
- case WDIOC_GET_PRETIMEOUT:
+ case WDIOC_OLD_IPMI_GET_PRETIMEOUT:
+ case WDIOC_GETPRETIMEOUT:
i = copy_to_user(argp, &pretimeout, sizeof(pretimeout));
if (i)
return -EFAULT;
Index: linux-2.6.16/include/linux/watchdog.h
===================================================================
--- linux-2.6.16.orig/include/linux/watchdog.h
+++ linux-2.6.16/include/linux/watchdog.h
@@ -28,6 +28,8 @@ struct watchdog_info {
#define WDIOC_KEEPALIVE _IOR(WATCHDOG_IOCTL_BASE, 5, int)
#define WDIOC_SETTIMEOUT _IOWR(WATCHDOG_IOCTL_BASE, 6, int)
#define WDIOC_GETTIMEOUT _IOR(WATCHDOG_IOCTL_BASE, 7, int)
+#define WDIOC_SETPRETIMEOUT _IOWR(WATCHDOG_IOCTL_BASE, 8, int)
+#define WDIOC_GETPRETIMEOUT _IOR(WATCHDOG_IOCTL_BASE, 9, int)
#define WDIOF_UNKNOWN -1 /* Unknown flag error */
#define WDIOS_UNKNOWN -1 /* Unknown status error */
@@ -41,6 +43,7 @@ struct watchdog_info {
#define WDIOF_POWEROVER 0x0040 /* Power over voltage */
#define WDIOF_SETTIMEOUT 0x0080 /* Set timeout (in seconds) */
#define WDIOF_MAGICCLOSE 0x0100 /* Supports magic close char */
+#define WDIOF_PRETIMEOUT 0x0200 /* Pretimeout (in seconds), get/set */
#define WDIOF_KEEPALIVEPING 0x8000 /* Keep alive ping reply */
#define WDIOS_DISABLECARD 0x0001 /* Turn off the watchdog timer */
-
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