5 files changed, 51 insertions, 0 deletions

diff --git a/arch/x86/include/asm/uv/uv.h b/arch/x86/include/asm/uv/uv.h
index c0a01b5d985b..3bb9491b7659 100644
--- a/arch/x86/include/asm/uv/uv.h
+++ b/arch/x86/include/asm/uv/uv.h
@@ -11,6 +11,7 @@ struct mm_struct;
 extern enum uv_system_type get_uv_system_type(void);
 extern int is_uv_system(void);
 extern void uv_cpu_init(void);
+extern void uv_nmi_init(void);
 extern void uv_system_init(void);
 extern const struct cpumask *uv_flush_tlb_others(const struct cpumask *cpumask,
                                                  struct mm_struct *mm,
diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index ea0e8ea15e15..60cc35269083 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -126,6 +126,7 @@ struct x86_cpuinit_ops {
  * @get_wallclock:              get time from HW clock like RTC etc.
  * @set_wallclock:              set time back to HW clock
  * @is_untracked_pat_range      exclude from PAT logic
+ * @nmi_init                    enable NMI on cpus
  */
 struct x86_platform_ops {
         unsigned long (*calibrate_tsc)(void);
@@ -133,6 +134,7 @@ struct x86_platform_ops {
         int (*set_wallclock)(unsigned long nowtime);
         void (*iommu_shutdown)(void);
         bool (*is_untracked_pat_range)(u64 start, u64 end);
+        void (*nmi_init)(void);
 };
 
 extern struct x86_init_ops x86_init;
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
 };