From: Aristeu Rozanski <aris@redhat.com>
Date: Wed, 20 Aug 2008 13:16:49 -0400
Subject: [x86_64] nmi: introduce do_nmi_callback
Message-id: 20080820171647.255361000@redhat.com
O-Subject: [RHEL5.3 PATCH 03/25] nmi: introduce do_nmi_callback
Bugzilla: 447618

https://bugzilla.redhat.com/show_bug.cgi?id=447618

Instead of repeating the test for unknown nmi types, simplify
unknown_nmi_panic_callback() and only call it when it's needed.

using do_nmi_callback2() as name because of existing do_nmi_callback()

Upstream: 3adbbcce9a49b900d4cc118cdccfdefa78bf1afb

diff --git a/arch/x86_64/kernel/nmi.c b/arch/x86_64/kernel/nmi.c
index 85f2fff..effad06 100644
--- a/arch/x86_64/kernel/nmi.c
+++ b/arch/x86_64/kernel/nmi.c
@@ -345,32 +345,21 @@ static void clear_msr_range(unsigned int base, unsigned int n)
 
 void setup_apic_nmi_watchdog(void)
 {
-	switch (boot_cpu_data.x86_vendor) {
-	case X86_VENDOR_AMD:
-		if ((boot_cpu_data.x86 != 15) && (boot_cpu_data.x86 != 16))
-			return;
-		if (strstr(boot_cpu_data.x86_model_id, "Screwdriver"))
-			return;
-		setup_k7_watchdog();
-		break;
-	case X86_VENDOR_INTEL:
-		if (cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON)) {
-			if (!setup_intel_arch_watchdog())
-				return;
-		} else if (boot_cpu_data.x86 == 15) {
-			if (!setup_p4_watchdog())
-				return;
-		} else {
+	if (__get_cpu_var(wd_enabled) == 1)
+ 		return;
+
+	switch (nmi_watchdog) {
+	case NMI_LOCAL_APIC:
+		__get_cpu_var(wd_enabled) = 1;
+		if (lapic_watchdog_init(nmi_hz) < 0) {
+			__get_cpu_var(wd_enabled) = 0;
 			return;
 		}
-
-		break;
-
-	default:
-		return;
-	}
-	lapic_nmi_owner = LAPIC_NMI_WATCHDOG;
-	nmi_active = 1;
+		/* FALL THROUGH */
+	case NMI_IO_APIC:
+		__get_cpu_var(wd_enabled) = 1;
+		atomic_inc(&nmi_active);
+ 	}
 }
 
 /*
@@ -498,6 +487,16 @@ void unset_nmi_callback(void)
 }
 EXPORT_SYMBOL_GPL(unset_nmi_callback);
 
+static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu);
+int do_nmi_callback2(struct pt_regs *regs, int cpu)
+{
+#ifdef CONFIG_SYSCTL
+	if (unknown_nmi_panic)
+		unknown_nmi_panic_callback(regs, cpu);
+#endif
+	return 0;
+}
+
 #ifdef CONFIG_SYSCTL
 
 static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu)
@@ -505,10 +504,9 @@ static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu)
 	unsigned char reason = get_nmi_reason();
 	char buf[64];
 
-	if (!(reason & 0xc0)) {
-		sprintf(buf, "NMI received for unknown reason %02x\n", reason);
-		die_nmi(buf,regs);
-	}
+	sprintf(buf, "NMI received for unknown reason %02x\n", reason);
+	die_nmi(buf,regs);
+
 	return 0;
 }
 
@@ -529,13 +527,10 @@ int proc_unknown_nmi_panic(struct ctl_table *table, int write, struct file *file
 		if (reserve_lapic_nmi() < 0) {
 			unknown_nmi_panic = 0;
 			return -EBUSY;
-		} else {
-			set_nmi_callback(unknown_nmi_panic_callback);
 		}
-	} else {
+	} else
 		release_lapic_nmi();
-		unset_nmi_callback();
-	}
+
 	return 0;
 }
 
diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c
index 97a7b4b..9274241 100644
--- a/arch/x86_64/kernel/traps.c
+++ b/arch/x86_64/kernel/traps.c
@@ -804,7 +804,8 @@ asmlinkage __kprobes void default_do_nmi(struct pt_regs *regs)
 			return;
 		}
 #endif
-		unknown_nmi_error(reason, regs);
+		if (!do_nmi_callback2(regs, cpu))
+			unknown_nmi_error(reason, regs);
 		return;
 	}
 	if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP)
diff --git a/include/asm-x86_64/nmi.h b/include/asm-x86_64/nmi.h
index 2974e5c..b5060dd 100644
--- a/include/asm-x86_64/nmi.h
+++ b/include/asm-x86_64/nmi.h
@@ -26,6 +26,14 @@ void set_nmi_callback(nmi_callback_t callback);
  */
 void unset_nmi_callback(void);
 
+/**
+ * do_nmi_callback2
+ *
+ * Check to see if a callback exists and execute it. Return 1
+ * if the handler exists and was handled successfully.
+ */
+int do_nmi_callback2(struct pt_regs *regs, int cpu);
+
 #ifdef CONFIG_PM
  
 /** Replace the PM callback routine for NMI. */