]> pilppa.org Git - linux-2.6-omap-h63xx.git/blobdiff - drivers/char/ipmi/ipmi_watchdog.c
IPMI: fix hotmod remove lock
[linux-2.6-omap-h63xx.git] / drivers / char / ipmi / ipmi_watchdog.c
index 41f78e2c158f453543ba8d315df7d0b580efa341..e686fc925168a16614cb41ed3932554f3217d3df 100644 (file)
 #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: "
@@ -166,8 +175,6 @@ static char expect_close;
 
 static int ifnum_to_use = -1;
 
-static DECLARE_RWSEM(register_sem);
-
 /* Parameters to ipmi_set_timeout */
 #define IPMI_SET_TIMEOUT_NO_HB                 0
 #define IPMI_SET_TIMEOUT_HB_IF_NECESSARY       1
@@ -193,11 +200,9 @@ static int set_param_int(const char *val, struct kernel_param *kp)
        if (endp == val)
                return -EINVAL;
 
-       down_read(&register_sem);
        *((int *)kp->arg) = l;
        if (watchdog_user)
                rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
-       up_read(&register_sem);
 
        return rv;
 }
@@ -226,17 +231,15 @@ static int set_param_str(const char *val, struct kernel_param *kp)
 
        s = strstrip(valcp);
 
-       down_read(&register_sem);
        rv = fn(s, NULL);
        if (rv)
-               goto out_unlock;
+               goto out;
 
        check_parms();
        if (watchdog_user)
                rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
 
- out_unlock:
-       up_read(&register_sem);
+ out:
        return rv;
 }
 
@@ -319,9 +322,12 @@ 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);
 
-static int ipmi_heartbeat(void);
-static void panic_halt_ipmi_heartbeat(void);
+#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
    timeout at one time, because we only have one copy of the data.
@@ -360,6 +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);
 
@@ -434,31 +443,75 @@ 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;
 }
 
-static void dummy_smi_free(struct ipmi_smi_msg *msg)
+static atomic_t panic_done_count = ATOMIC_INIT(0);
+
+static void panic_smi_free(struct ipmi_smi_msg *msg)
 {
+       atomic_dec(&panic_done_count);
 }
-static void dummy_recv_free(struct ipmi_recv_msg *msg)
+static void panic_recv_free(struct ipmi_recv_msg *msg)
 {
+       atomic_dec(&panic_done_count);
+}
+
+static struct ipmi_smi_msg panic_halt_heartbeat_smi_msg =
+{
+       .done = panic_smi_free
+};
+static struct ipmi_recv_msg panic_halt_heartbeat_recv_msg =
+{
+       .done = panic_recv_free
+};
+
+static void panic_halt_ipmi_heartbeat(void)
+{
+       struct kernel_ipmi_msg             msg;
+       struct ipmi_system_interface_addr addr;
+       int rv;
+
+       /* Don't reset the timer if we have the timer turned off, that
+           re-enables the watchdog. */
+       if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
+               return;
+
+       addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
+       addr.channel = IPMI_BMC_CHANNEL;
+       addr.lun = 0;
+
+       msg.netfn = 0x06;
+       msg.cmd = IPMI_WDOG_RESET_TIMER;
+       msg.data = NULL;
+       msg.data_len = 0;
+       rv = ipmi_request_supply_msgs(watchdog_user,
+                                     (struct ipmi_addr *) &addr,
+                                     0,
+                                     &msg,
+                                     NULL,
+                                     &panic_halt_heartbeat_smi_msg,
+                                     &panic_halt_heartbeat_recv_msg,
+                                     1);
+       if (!rv)
+               atomic_add(2, &panic_done_count);
 }
+
 static struct ipmi_smi_msg panic_halt_smi_msg =
 {
-       .done = dummy_smi_free
+       .done = panic_smi_free
 };
 static struct ipmi_recv_msg panic_halt_recv_msg =
 {
-       .done = dummy_recv_free
+       .done = panic_recv_free
 };
 
 /* Special call, doesn't claim any locks.  This is only to be called
@@ -470,13 +523,21 @@ static void panic_halt_ipmi_set_timeout(void)
        int send_heartbeat_now;
        int rv;
 
+       /* Wait for the messages to be free. */
+       while (atomic_read(&panic_done_count) != 0)
+               ipmi_poll_interface(watchdog_user);
        rv = i_ipmi_set_timeout(&panic_halt_smi_msg,
                                &panic_halt_recv_msg,
                                &send_heartbeat_now);
        if (!rv) {
+               atomic_add(2, &panic_done_count);
                if (send_heartbeat_now)
                        panic_halt_ipmi_heartbeat();
-       }
+       } else
+               printk(KERN_WARNING PFX
+                      "Unable to extend the watchdog timeout.");
+       while (atomic_read(&panic_done_count) != 0)
+               ipmi_poll_interface(watchdog_user);
 }
 
 /* We use a semaphore to make sure that only one thing can send a
@@ -505,24 +566,14 @@ static struct ipmi_recv_msg heartbeat_recv_msg =
        .done = heartbeat_free_recv
 };
  
-static struct ipmi_smi_msg panic_halt_heartbeat_smi_msg =
-{
-       .done = dummy_smi_free
-};
-static struct ipmi_recv_msg panic_halt_heartbeat_recv_msg =
-{
-       .done = dummy_recv_free
-};
 static int ipmi_heartbeat(void)
 {
        struct kernel_ipmi_msg            msg;
        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;
@@ -533,7 +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);
        }
 
@@ -586,35 +636,6 @@ static int ipmi_heartbeat(void)
        return rv;
 }
 
-static void panic_halt_ipmi_heartbeat(void)
-{
-       struct kernel_ipmi_msg             msg;
-       struct ipmi_system_interface_addr addr;
-
-
-       /* Don't reset the timer if we have the timer turned off, that
-           re-enables the watchdog. */
-       if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
-               return;
-
-       addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
-       addr.channel = IPMI_BMC_CHANNEL;
-       addr.lun = 0;
-
-       msg.netfn = 0x06;
-       msg.cmd = IPMI_WDOG_RESET_TIMER;
-       msg.data = NULL;
-       msg.data_len = 0;
-       ipmi_request_supply_msgs(watchdog_user,
-                                (struct ipmi_addr *) &addr,
-                                0,
-                                &msg,
-                                NULL,
-                                &panic_halt_heartbeat_smi_msg,
-                                &panic_halt_heartbeat_recv_msg,
-                                1);
-}
-
 static struct watchdog_info ident =
 {
        .options        = 0,    /* WDIOF_SETTIMEOUT, */
@@ -895,7 +916,6 @@ static void ipmi_register_watchdog(int ipmi_intf)
 {
        int rv = -EBUSY;
 
-       down_write(&register_sem);
        if (watchdog_user)
                goto out;
 
@@ -921,15 +941,56 @@ static void ipmi_register_watchdog(int ipmi_intf)
                printk(KERN_CRIT PFX "Unable to register misc device\n");
        }
 
- out:
-       up_write(&register_sem);
+#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. */
                start_now = 0; /* Disable this function after first startup. */
                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);
        }
 }
 
@@ -937,8 +998,6 @@ static void ipmi_unregister_watchdog(int ipmi_intf)
 {
        int rv;
 
-       down_write(&register_sem);
-
        if (!watchdog_user)
                goto out;
 
@@ -963,20 +1022,44 @@ static void ipmi_unregister_watchdog(int ipmi_intf)
        watchdog_user = NULL;
 
  out:
-       up_write(&register_sem);
+       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. */
@@ -985,18 +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,
@@ -1009,7 +1086,7 @@ static int wdog_reboot_handler(struct notifier_block *this,
                /* Make sure we only do this once. */
                reboot_event_handled = 1;
 
-               if (code == SYS_DOWN || code == SYS_HALT) {
+               if (code == SYS_POWER_OFF || code == SYS_HALT) {
                        /* Disable the WDT if we are shutting down. */
                        ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
                        panic_halt_ipmi_set_timeout();
@@ -1113,7 +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
@@ -1147,7 +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;
 
@@ -1160,20 +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");
@@ -1181,7 +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
@@ -1217,9 +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);
@@ -1238,9 +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,