Revert "ipmi: add new IPMI nmi watchdog handling"

This reverts commit f64da958dfc83335de1d2bef9d3868f30feb4e53.

Andi Kleen is unhappy with the changes, and they really do not seem
worth it.  IPMI could use DIE_NMI_IPI instead of the new callback, even
though that ends up having its own set of problems too, mainly because
the IPMI code cannot really know the NMI was from IPMI or not.

Manually fix up conflicts in arch/x86_64/kernel/traps.c and
drivers/char/ipmi/ipmi_watchdog.c.

Cc: Andi Kleen <ak@suse.de>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Corey Minyard <minyard@acm.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

5 files changed, 42 insertions, 102 deletions

diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
index c05e7e861b29..90da0575fcff 100644
--- a/arch/i386/kernel/traps.c
+++ b/arch/i386/kernel/traps.c
@@ -733,11 +733,6 @@ static __kprobes void default_do_nmi(struct pt_regs * regs)
                  */
                 if (nmi_watchdog_tick(regs, reason))
                         return;
-#endif
-                if (notify_die(DIE_NMI_POST, "nmi_post", regs, reason, 2, 0)
-                                                        == NOTIFY_STOP)
-                        return;
-#ifdef CONFIG_X86_LOCAL_APIC
                 if (!do_nmi_callback(regs, smp_processor_id()))
 #endif
                         unknown_nmi_error(reason, regs);
diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c
index d28f01379b9b..cb29fb96948d 100644
--- a/arch/x86_64/kernel/traps.c
+++ b/arch/x86_64/kernel/traps.c
@@ -776,9 +776,6 @@ asmlinkage __kprobes void default_do_nmi(struct pt_regs *regs)
                  */
                 if (nmi_watchdog_tick(regs,reason))
                         return;
-                if (notify_die(DIE_NMI_POST, "nmi_post", regs, reason, 2, 0)
-                                                                == NOTIFY_STOP)
-                        return;
                 if (!do_nmi_callback(regs,cpu))
                         unknown_nmi_error(reason, regs);
 
diff --git a/drivers/char/ipmi/ipmi_watchdog.c b/drivers/char/ipmi/ipmi_watchdog.c
index 147c12047cf3..41f78e2c158f 100644
--- a/drivers/char/ipmi/ipmi_watchdog.c
+++ b/drivers/char/ipmi/ipmi_watchdog.c
@@ -50,18 +50,10 @@
 #include <linux/poll.h>
 #include <linux/string.h>
 #include <linux/ctype.h>
-#include <linux/delay.h>
 #include <asm/atomic.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. */
-#define HAVE_DIE_NMI_POST
+#ifdef CONFIG_X86_LOCAL_APIC
+#include <asm/apic.h>
 #endif
 
 #define PFX "IPMI Watchdog: "
@@ -327,11 +319,6 @@ 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_POST
-static int testing_nmi;
-static int nmi_handler_registered;
-#endif
-
 static int ipmi_heartbeat(void);
 static void panic_halt_ipmi_heartbeat(void);
 
@@ -373,10 +360,6 @@ 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. */
-        ipmi_start_timer_on_heartbeat = 0;
-        pretimeout_since_last_heartbeat = 0;
-
         data[0] = 0;
         WDOG_SET_TIMER_USE(data[0], WDOG_TIMER_USE_SMS_OS);
 
@@ -451,12 +434,13 @@ 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;
@@ -536,10 +520,12 @@ 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;
                 ipmi_watchdog_state = action_val;
                 return ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
         } else if (pretimeout_since_last_heartbeat) {
@@ -547,6 +533,7 @@ 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);
         }
 
@@ -934,45 +921,6 @@ static void ipmi_register_watchdog(int ipmi_intf)
                 printk(KERN_CRIT PFX "Unable to register misc device\n");
         }
 
-#ifdef HAVE_DIE_NMI_POST
-        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:
         up_write(&register_sem);
 
@@ -982,10 +930,6 @@ 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);
         }
 }
 
@@ -1022,28 +966,17 @@ static void ipmi_unregister_watchdog(int ipmi_intf)
         up_write(&register_sem);
 }
 
-#ifdef HAVE_DIE_NMI_POST
+#ifdef HAVE_NMI_HANDLER
 static int
-ipmi_nmi(struct notifier_block *self, unsigned long val, void *data)
+ipmi_nmi(void *dev_id, int cpu, int handled)
 {
-        if (val != DIE_NMI_POST)
-                return NOTIFY_OK;
-
-        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_OK;
-
-        if (preaction_val != WDOG_PRETIMEOUT_NMI)
-                return NOTIFY_OK;
+                return NOTIFY_DONE;
 
         /* If no one else handled the NMI, we assume it was the IPMI
            watchdog. */
-        if (preop_val == WDOG_PREOP_PANIC) {
+        if ((!handled) && (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. */
@@ -1052,12 +985,18 @@ ipmi_nmi(struct notifier_block *self, unsigned long val, void *data)
                         panic(PFX "pre-timeout");
         }
 
-        return NOTIFY_STOP;
+        return NOTIFY_DONE;
 }
 
-static struct notifier_block ipmi_nmi_handler = {
-        .notifier_call = ipmi_nmi
+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. */
 };
+int nmi_handler_registered;
 #endif
 
 static int wdog_reboot_handler(struct notifier_block *this,
@@ -1174,7 +1113,7 @@ 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_DIE_NMI_POST
+#ifdef HAVE_NMI_HANDLER
         else if (strcmp(inval, "pre_nmi") == 0)
                 preaction_val = WDOG_PRETIMEOUT_NMI;
 #endif
@@ -1208,7 +1147,7 @@ static int preop_op(const char *inval, char *outval)
 
 static void check_parms(void)
 {
-#ifdef HAVE_DIE_NMI_POST
+#ifdef HAVE_NMI_HANDLER
         int do_nmi = 0;
         int rv;
 
@@ -1221,9 +1160,20 @@ 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 = register_die_notifier(&ipmi_nmi_handler);
+                rv = request_nmi(&ipmi_nmi_handler);
                 if (rv) {
                         printk(KERN_WARNING PFX
                                "Can't register nmi handler\n");
@@ -1231,7 +1181,7 @@ static void check_parms(void)
                 } else
                         nmi_handler_registered = 1;
         } else if (!do_nmi && nmi_handler_registered) {
-                unregister_die_notifier(&ipmi_nmi_handler);
+                release_nmi(&ipmi_nmi_handler);
                 nmi_handler_registered = 0;
         }
 #endif
@@ -1267,9 +1217,9 @@ static int __init ipmi_wdog_init(void)
 
         rv = ipmi_smi_watcher_register(&smi_watcher);
         if (rv) {
-#ifdef HAVE_DIE_NMI_POST
-                if (nmi_handler_registered)
-                        unregister_die_notifier(&ipmi_nmi_handler);
+#ifdef HAVE_NMI_HANDLER
+                if (preaction_val == WDOG_PRETIMEOUT_NMI)
+                        release_nmi(&ipmi_nmi_handler);
 #endif
                 atomic_notifier_chain_unregister(&panic_notifier_list,
                                                  &wdog_panic_notifier);
@@ -1288,9 +1238,9 @@ static void __exit ipmi_wdog_exit(void)
         ipmi_smi_watcher_unregister(&smi_watcher);
         ipmi_unregister_watchdog(watchdog_ifnum);
 
-#ifdef HAVE_DIE_NMI_POST
+#ifdef HAVE_NMI_HANDLER
         if (nmi_handler_registered)
-                unregister_die_notifier(&ipmi_nmi_handler);
+                release_nmi(&ipmi_nmi_handler);
 #endif
 
         atomic_notifier_chain_unregister(&panic_notifier_list,
diff --git a/include/asm-i386/kdebug.h b/include/asm-i386/kdebug.h
index 05c3117788b9..a185b5f73e7f 100644
--- a/include/asm-i386/kdebug.h
+++ b/include/asm-i386/kdebug.h
@@ -27,7 +27,6 @@ enum die_val {
         DIE_GPF,
         DIE_CALL,
         DIE_NMI_IPI,
-        DIE_NMI_POST,
         DIE_PAGE_FAULT,
 };
 
diff --git a/include/asm-x86_64/kdebug.h b/include/asm-x86_64/kdebug.h
index 74feae945a26..d7e2bcf49e4f 100644
--- a/include/asm-x86_64/kdebug.h
+++ b/include/asm-x86_64/kdebug.h
@@ -22,7 +22,6 @@ enum die_val {
         DIE_GPF,
         DIE_CALL,
         DIE_NMI_IPI,
-        DIE_NMI_POST,
         DIE_PAGE_FAULT,
 };