[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 <thomas.mingarelli@hp.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

1 files changed, 21 insertions, 5 deletions

diff --git a/drivers/watchdog/hpwdt.c b/drivers/watchdog/hpwdt.c
index c0b9169ba5d5..a6c5674c78e6 100644
--- a/drivers/watchdog/hpwdt.c
+++ b/drivers/watchdog/hpwdt.c
@@ -120,7 +120,8 @@ static int nowayout = WATCHDOG_NOWAYOUT;
 static char expect_release;
 static unsigned long hpwdt_is_open;
 static unsigned int allow_kdump;
-static int hpwdt_nmi_sourcing;
+static unsigned int hpwdt_nmi_sourcing;
+static unsigned int priority;           /* hpwdt at end of die_notify list */
 
 static void __iomem *pci_mem_addr;              /* the PCI-memory address */
 static unsigned long __iomem *hpwdt_timer_reg;
@@ -623,7 +624,7 @@ static struct miscdevice hpwdt_miscdev = {
 
 static struct notifier_block die_notifier = {
         .notifier_call = hpwdt_pretimeout,
-        .priority = 0x7FFFFFFF,
+        .priority = 0,
 };
 
 /*
@@ -641,7 +642,8 @@ static void __devinit hpwdt_check_nmi_sourcing(struct pci_dev *dev)
                 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");
+                        "functionality you must reboot with nmi_watchdog=0 "
+                        "and load the hpwdt driver with priority=1.\n");
 }
 #else
 static void __devinit hpwdt_check_nmi_sourcing(struct pci_dev *dev)
@@ -714,6 +716,14 @@ static int __devinit hpwdt_init_one(struct pci_dev *dev,
         cmn_regs.u1.rah = 0x0D;
         cmn_regs.u1.ral = 0x02;
 
+        /*
+         * If the priority is set to 1, then we will be put first on the
+         * die notify list to handle a critical NMI. The default is to
+         * be last so other users of the NMI signal can function.
+         */
+        if (priority)
+                die_notifier.priority = 0x7FFFFFFF;
+
         retval = register_die_notifier(&die_notifier);
         if (retval != 0) {
                 dev_warn(&dev->dev,
@@ -733,9 +743,11 @@ static int __devinit hpwdt_init_one(struct pci_dev *dev,
         printk(KERN_INFO
                 "hp Watchdog Timer Driver: %s"
                 ", timer margin: %d seconds (nowayout=%d)"
-                ", allow kernel dump: %s (default = 0/OFF).\n",
+                ", allow kernel dump: %s (default = 0/OFF)"
+                ", priority: %s (default = 0/LAST).\n",
                 HPWDT_VERSION, soft_margin, nowayout,
-                (allow_kdump == 0) ? "OFF" : "ON");
+                (allow_kdump == 0) ? "OFF" : "ON",
+                (priority == 0) ? "LAST" : "FIRST");
 
         return 0;
 
@@ -798,5 +810,9 @@ module_param(nowayout, int, 0);
 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 
+module_param(priority, int, 0);
+MODULE_PARM_DESC(priority, "The hpwdt driver handles NMIs first or last"
+                " (default = 0/Last)\n");
+
 module_init(hpwdt_init);
 module_exit(hpwdt_cleanup);