3 files changed, 48 insertions, 0 deletions

diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
index 6ef2899eb861..4b8dbb256147 100644
--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -21,6 +21,7 @@
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/pci.h>
+#include <linux/kdebug.h>
 
 #include <asm/uv/uv_mmrs.h>
 #include <asm/uv/uv_hub.h>
@@ -41,6 +42,7 @@ static enum uv_system_type uv_system_type;
 static u64 gru_start_paddr, gru_end_paddr;
 int uv_min_hub_revision_id;
 EXPORT_SYMBOL_GPL(uv_min_hub_revision_id);
+static DEFINE_SPINLOCK(uv_nmi_lock);
 
 static inline bool is_GRU_range(u64 start, u64 end)
 {
@@ -74,6 +76,7 @@ static int __init uv_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
 	if (!strcmp(oem_id, "SGI")) {
 		nodeid = early_get_nodeid();
 		x86_platform.is_untracked_pat_range =  uv_is_untracked_pat_range;
+		x86_platform.nmi_init = uv_nmi_init;
 		if (!strcmp(oem_table_id, "UVL"))
 			uv_system_type = UV_LEGACY_APIC;
 		else if (!strcmp(oem_table_id, "UVX"))
@@ -596,6 +599,46 @@ void __cpuinit uv_cpu_init(void)
 		set_x2apic_extra_bits(uv_hub_info->pnode);
 }
 
+/*
+ * When NMI is received, print a stack trace.
+ */
+int uv_handle_nmi(struct notifier_block *self, unsigned long reason, void *data)
+{
+	if (reason != DIE_NMI_IPI)
+		return NOTIFY_OK;
+	/*
+	 * Use a lock so only one cpu prints at a time
+	 * to prevent intermixed output.
+	 */
+	spin_lock(&uv_nmi_lock);
+	pr_info("NMI stack dump cpu %u:\n", smp_processor_id());
+	dump_stack();
+	spin_unlock(&uv_nmi_lock);
+
+	return NOTIFY_STOP;
+}
+
+static struct notifier_block uv_dump_stack_nmi_nb = {
+	.notifier_call	= uv_handle_nmi
+};
+
+void uv_register_nmi_notifier(void)
+{
+	if (register_die_notifier(&uv_dump_stack_nmi_nb))
+		printk(KERN_WARNING "UV NMI handler failed to register\n");
+}
+
+void uv_nmi_init(void)
+{
+	unsigned int value;
+
+	/*
+	 * Unmask NMI on all cpus
+	 */
+	value = apic_read(APIC_LVT1) | APIC_DM_NMI;
+	value &= ~APIC_LVT_MASKED;
+	apic_write(APIC_LVT1, value);
+}
 
 void __init uv_system_init(void)
 {
@@ -717,6 +760,7 @@ void __init uv_system_init(void)
 
 	uv_cpu_init();
 	uv_scir_register_cpu_notifier();
+	uv_register_nmi_notifier();
 	proc_mkdir("sgi_uv", NULL);
 
 	/* register Legacy VGA I/O redirection handler */
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 678d0b8c26f3..838a118876c0 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -320,6 +320,7 @@ notrace static void __cpuinit start_secondary(void *unused)
 	unlock_vector_lock();
 	ipi_call_unlock();
 	per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
+	x86_platform.nmi_init();
 
 	/* enable local interrupts */
 	local_irq_enable();
diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
index ccd179dec36e..ee5746c94628 100644
--- a/arch/x86/kernel/x86_init.c
+++ b/arch/x86/kernel/x86_init.c
@@ -76,10 +76,13 @@ struct x86_cpuinit_ops x86_cpuinit __cpuinitdata = {
 	.setup_percpu_clockev		= setup_secondary_APIC_clock,
 };
 
+static void default_nmi_init(void) { };
+
 struct x86_platform_ops x86_platform = {
 	.calibrate_tsc			= native_calibrate_tsc,
 	.get_wallclock			= mach_get_cmos_time,
 	.set_wallclock			= mach_set_rtc_mmss,
 	.iommu_shutdown			= iommu_shutdown_noop,
 	.is_untracked_pat_range		= is_ISA_range,
+	.nmi_init			= default_nmi_init
 };