2 files changed, 110 insertions, 44 deletions

diff --git a/Documentation/IPMI.txt b/Documentation/IPMI.txt
index 83b05459eb5c..bc38283379f0 100644
--- a/Documentation/IPMI.txt
+++ b/Documentation/IPMI.txt
@@ -584,9 +584,11 @@ The watchdog will panic and start a 120 second reset timeout if it
 gets a pre-action.  During a panic or a reboot, the watchdog will
 start a 120 timer if it is running to make sure the reboot occurs.
 
-Note that if you use the NMI preaction for the watchdog, you MUST
-NOT use nmi watchdog mode 1.  If you use the NMI watchdog, you
-must use mode 2.
+Note that if you use the NMI preaction for the watchdog, you MUST NOT
+use the nmi watchdog.  There is no reasonable way to tell if an NMI
+comes from the IPMI controller, so it must assume that if it gets an
+otherwise unhandled NMI, it must be from IPMI and it will panic
+immediately.
 
 Once you open the watchdog timer, you must write a 'V' character to the
 device to close it, or the timer will not stop.  This is a new semantic
diff --git a/drivers/char/ipmi/ipmi_watchdog.c b/drivers/char/ipmi/ipmi_watchdog.c
index 19a8683bd25d..e686fc925168 100644
--- a/drivers/char/ipmi/ipmi_watchdog.c
+++ b/drivers/char/ipmi/ipmi_watchdog.c
@@ -50,10 +50,19 @@
 #include <linux/poll.h>
 #include <linux/string.h>
 #include <linux/ctype.h>
+#include <linux/delay.h>
 #include <asm/atomic.h>
 
-#ifdef CONFIG_X86_LOCAL_APIC
-#include <asm/apic.h>
+#ifdef CONFIG_X86
+/* This is ugly, but I've determined that x86 is the only architecture
+   that can reasonably support the IPMI NMI watchdog timeout at this
+   time.  If another architecture adds this capability somehow, it
+   will have to be a somewhat different mechanism and I have no idea
+   how it will work.  So in the unlikely event that another
+   architecture supports this, we can figure out a good generic
+   mechanism for it at that time. */
+#include <asm/kdebug.h>
+#define HAVE_DIE_NMI
 #endif
 
 #define PFX "IPMI Watchdog: "
@@ -313,6 +322,11 @@ static unsigned char ipmi_version_minor;
 /* If a pretimeout occurs, this is used to allow only one panic to happen. */
 static atomic_t preop_panic_excl = ATOMIC_INIT(-1);
 
+#ifdef HAVE_DIE_NMI
+static int testing_nmi;
+static int nmi_handler_registered;
+#endif
+
 static int ipmi_heartbeat(void);
 
 /* We use a mutex to make sure that only one thing can send a set
@@ -352,6 +366,9 @@ static int i_ipmi_set_timeout(struct ipmi_smi_msg  *smi_msg,
         int                               hbnow = 0;
 
 
+        /* These can be cleared as we are setting the timeout. */
+        pretimeout_since_last_heartbeat = 0;
+
         data[0] = 0;
         WDOG_SET_TIMER_USE(data[0], WDOG_TIMER_USE_SMS_OS);
 
@@ -426,13 +443,12 @@ static int ipmi_set_timeout(int do_heartbeat)
 
         wait_for_completion(&set_timeout_wait);
 
+        mutex_unlock(&set_timeout_lock);
+
         if ((do_heartbeat == IPMI_SET_TIMEOUT_FORCE_HB)
             || ((send_heartbeat_now)
                 && (do_heartbeat == IPMI_SET_TIMEOUT_HB_IF_NECESSARY)))
-        {
                 rv = ipmi_heartbeat();
-        }
-        mutex_unlock(&set_timeout_lock);
 
 out:
         return rv;
@@ -556,9 +572,8 @@ static int ipmi_heartbeat(void)
         int                               rv;
         struct ipmi_system_interface_addr addr;
 
-        if (ipmi_ignore_heartbeat) {
+        if (ipmi_ignore_heartbeat)
                 return 0;
-        }
 
         if (ipmi_start_timer_on_heartbeat) {
                 ipmi_start_timer_on_heartbeat = 0;
@@ -569,7 +584,6 @@ static int ipmi_heartbeat(void)
                    We don't want to set the action, though, we want to
                    leave that alone (thus it can't be combined with the
                    above operation. */
-                pretimeout_since_last_heartbeat = 0;
                 return ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
         }
 
@@ -927,6 +941,45 @@ static void ipmi_register_watchdog(int ipmi_intf)
                 printk(KERN_CRIT PFX "Unable to register misc device\n");
         }
 
+#ifdef HAVE_DIE_NMI
+        if (nmi_handler_registered) {
+                int old_pretimeout = pretimeout;
+                int old_timeout = timeout;
+                int old_preop_val = preop_val;
+
+                /* Set the pretimeout to go off in a second and give
+                   ourselves plenty of time to stop the timer. */
+                ipmi_watchdog_state = WDOG_TIMEOUT_RESET;
+                preop_val = WDOG_PREOP_NONE; /* Make sure nothing happens */
+                pretimeout = 99;
+                timeout = 100;
+
+                testing_nmi = 1;
+
+                rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
+                if (rv) {
+                        printk(KERN_WARNING PFX "Error starting timer to"
+                               " test NMI: 0x%x.  The NMI pretimeout will"
+                               " likely not work\n", rv);
+                        rv = 0;
+                        goto out_restore;
+                }
+
+                msleep(1500);
+
+                if (testing_nmi != 2) {
+                        printk(KERN_WARNING PFX "IPMI NMI didn't seem to"
+                               " occur.  The NMI pretimeout will"
+                               " likely not work\n");
+                }
+        out_restore:
+                testing_nmi = 0;
+                preop_val = old_preop_val;
+                pretimeout = old_pretimeout;
+                timeout = old_timeout;
+        }
+#endif
+
  out:
         if ((start_now) && (rv == 0)) {
                 /* Run from startup, so start the timer now. */
@@ -934,6 +987,10 @@ static void ipmi_register_watchdog(int ipmi_intf)
                 ipmi_watchdog_state = action_val;
                 ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
                 printk(KERN_INFO PFX "Starting now!\n");
+        } else {
+                /* Stop the timer now. */
+                ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
+                ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
         }
 }
 
@@ -968,17 +1025,41 @@ static void ipmi_unregister_watchdog(int ipmi_intf)
         return;
 }
 
-#ifdef HAVE_NMI_HANDLER
+#ifdef HAVE_DIE_NMI
 static int
-ipmi_nmi(void *dev_id, int cpu, int handled)
+ipmi_nmi(struct notifier_block *self, unsigned long val, void *data)
 {
+        struct die_args *args = data;
+
+        if (val != DIE_NMI)
+                return NOTIFY_OK;
+
+        /* Hack, if it's a memory or I/O error, ignore it. */
+        if (args->err & 0xc0)
+                return NOTIFY_OK;
+
+        /*
+         * If we get here, it's an NMI that's not a memory or I/O
+         * error.  We can't truly tell if it's from IPMI or not
+         * without sending a message, and sending a message is almost
+         * impossible because of locking.
+         */
+
+        if (testing_nmi) {
+                testing_nmi = 2;
+                return NOTIFY_STOP;
+        }
+
         /* If we are not expecting a timeout, ignore it. */
         if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
-                return NOTIFY_DONE;
+                return NOTIFY_OK;
+
+        if (preaction_val != WDOG_PRETIMEOUT_NMI)
+                return NOTIFY_OK;
 
         /* If no one else handled the NMI, we assume it was the IPMI
            watchdog. */
-        if ((!handled) && (preop_val == WDOG_PREOP_PANIC)) {
+        if (preop_val == WDOG_PREOP_PANIC) {
                 /* On some machines, the heartbeat will give
                    an error and not work unless we re-enable
                    the timer.   So do so. */
@@ -987,18 +1068,12 @@ ipmi_nmi(void *dev_id, int cpu, int handled)
                         panic(PFX "pre-timeout");
         }
 
-        return NOTIFY_DONE;
+        return NOTIFY_STOP;
 }
 
-static struct nmi_handler ipmi_nmi_handler =
-{
-        .link     = LIST_HEAD_INIT(ipmi_nmi_handler.link),
-        .dev_name = "ipmi_watchdog",
-        .dev_id   = NULL,
-        .handler  = ipmi_nmi,
-        .priority = 0, /* Call us last. */
+static struct notifier_block ipmi_nmi_handler = {
+        .notifier_call = ipmi_nmi
 };
-int nmi_handler_registered;
 #endif
 
 static int wdog_reboot_handler(struct notifier_block *this,
@@ -1115,7 +1190,7 @@ static int preaction_op(const char *inval, char *outval)
                 preaction_val = WDOG_PRETIMEOUT_NONE;
         else if (strcmp(inval, "pre_smi") == 0)
                 preaction_val = WDOG_PRETIMEOUT_SMI;
-#ifdef HAVE_NMI_HANDLER
+#ifdef HAVE_DIE_NMI
         else if (strcmp(inval, "pre_nmi") == 0)
                 preaction_val = WDOG_PRETIMEOUT_NMI;
 #endif
@@ -1149,7 +1224,7 @@ static int preop_op(const char *inval, char *outval)
 
 static void check_parms(void)
 {
-#ifdef HAVE_NMI_HANDLER
+#ifdef HAVE_DIE_NMI
         int do_nmi = 0;
         int rv;
 
@@ -1162,20 +1237,9 @@ static void check_parms(void)
                         preop_op("preop_none", NULL);
                         do_nmi = 0;
                 }
-#ifdef CONFIG_X86_LOCAL_APIC
-                if (nmi_watchdog == NMI_IO_APIC) {
-                        printk(KERN_WARNING PFX "nmi_watchdog is set to IO APIC"
-                               " mode (value is %d), that is incompatible"
-                               " with using NMI in the IPMI watchdog."
-                               " Disabling IPMI nmi pretimeout.\n",
-                               nmi_watchdog);
-                        preaction_val = WDOG_PRETIMEOUT_NONE;
-                        do_nmi = 0;
-                }
-#endif
         }
         if (do_nmi && !nmi_handler_registered) {
-                rv = request_nmi(&ipmi_nmi_handler);
+                rv = register_die_notifier(&ipmi_nmi_handler);
                 if (rv) {
                         printk(KERN_WARNING PFX
                                "Can't register nmi handler\n");
@@ -1183,7 +1247,7 @@ static void check_parms(void)
                 } else
                         nmi_handler_registered = 1;
         } else if (!do_nmi && nmi_handler_registered) {
-                release_nmi(&ipmi_nmi_handler);
+                unregister_die_notifier(&ipmi_nmi_handler);
                 nmi_handler_registered = 0;
         }
 #endif
@@ -1219,9 +1283,9 @@ static int __init ipmi_wdog_init(void)
 
         rv = ipmi_smi_watcher_register(&smi_watcher);
         if (rv) {
-#ifdef HAVE_NMI_HANDLER
-                if (preaction_val == WDOG_PRETIMEOUT_NMI)
-                        release_nmi(&ipmi_nmi_handler);
+#ifdef HAVE_DIE_NMI
+                if (nmi_handler_registered)
+                        unregister_die_notifier(&ipmi_nmi_handler);
 #endif
                 atomic_notifier_chain_unregister(&panic_notifier_list,
                                                  &wdog_panic_notifier);
@@ -1240,9 +1304,9 @@ static void __exit ipmi_wdog_exit(void)
         ipmi_smi_watcher_unregister(&smi_watcher);
         ipmi_unregister_watchdog(watchdog_ifnum);
 
-#ifdef HAVE_NMI_HANDLER
+#ifdef HAVE_DIE_NMI
         if (nmi_handler_registered)
-                release_nmi(&ipmi_nmi_handler);
+                unregister_die_notifier(&ipmi_nmi_handler);
 #endif
 
         atomic_notifier_chain_unregister(&panic_notifier_list,