7 files changed, 130 insertions, 8 deletions

diff --git a/arch/Kconfig b/arch/Kconfig
index acda512da2e2..4877a8c8ee16 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -151,4 +151,11 @@ config HAVE_MIXED_BREAKPOINTS_REGS
 config HAVE_USER_RETURN_NOTIFIER
         bool
 
+config HAVE_PERF_EVENTS_NMI
+        bool
+        help
+          System hardware can generate an NMI using the perf event
+          subsystem.  Also has support for calculating CPU cycle events
+          to determine how many clock cycles in a given period.
+
 source "kernel/gcov/Kconfig"
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index dcb0593b4a66..6f77afa6bca9 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -55,6 +55,7 @@ config X86
         select HAVE_HW_BREAKPOINT
         select HAVE_MIXED_BREAKPOINTS_REGS
         select PERF_EVENTS
+        select HAVE_PERF_EVENTS_NMI
         select ANON_INODES
         select HAVE_ARCH_KMEMCHECK
         select HAVE_USER_RETURN_NOTIFIER
diff --git a/arch/x86/include/asm/nmi.h b/arch/x86/include/asm/nmi.h
index 93da9c3f3341..932f0f86b4b7 100644
--- a/arch/x86/include/asm/nmi.h
+++ b/arch/x86/include/asm/nmi.h
@@ -17,7 +17,9 @@ int do_nmi_callback(struct pt_regs *regs, int cpu);
 
 extern void die_nmi(char *str, struct pt_regs *regs, int do_panic);
 extern int check_nmi_watchdog(void);
+#if !defined(CONFIG_LOCKUP_DETECTOR)
 extern int nmi_watchdog_enabled;
+#endif
 extern int avail_to_resrv_perfctr_nmi_bit(unsigned int);
 extern int reserve_perfctr_nmi(unsigned int);
 extern void release_perfctr_nmi(unsigned int);
diff --git a/arch/x86/kernel/apic/Makefile b/arch/x86/kernel/apic/Makefile
index 565c1bfc507d..910f20b457c4 100644
--- a/arch/x86/kernel/apic/Makefile
+++ b/arch/x86/kernel/apic/Makefile
@@ -2,7 +2,12 @@
 # Makefile for local APIC drivers and for the IO-APIC code
 #
 
-obj-$(CONFIG_X86_LOCAL_APIC)    += apic.o apic_noop.o probe_$(BITS).o ipi.o nmi.o
+obj-$(CONFIG_X86_LOCAL_APIC)    += apic.o apic_noop.o probe_$(BITS).o ipi.o
+ifneq ($(CONFIG_HARDLOCKUP_DETECTOR),y)
+obj-$(CONFIG_X86_LOCAL_APIC)    += nmi.o
+endif
+obj-$(CONFIG_HARDLOCKUP_DETECTOR)       += hw_nmi.o
+
 obj-$(CONFIG_X86_IO_APIC)       += io_apic.o
 obj-$(CONFIG_SMP)               += ipi.o
 
diff --git a/arch/x86/kernel/apic/hw_nmi.c b/arch/x86/kernel/apic/hw_nmi.c
new file mode 100644
index 000000000000..cefd6942f0e9
--- /dev/null
+++ b/arch/x86/kernel/apic/hw_nmi.c
@@ -0,0 +1,107 @@
+/*
+ *  HW NMI watchdog support
+ *
+ *  started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
+ *
+ *  Arch specific calls to support NMI watchdog
+ *
+ *  Bits copied from original nmi.c file
+ *
+ */
+#include <asm/apic.h>
+
+#include <linux/cpumask.h>
+#include <linux/kdebug.h>
+#include <linux/notifier.h>
+#include <linux/kprobes.h>
+#include <linux/nmi.h>
+#include <linux/module.h>
+
+/* For reliability, we're prepared to waste bits here. */
+static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
+
+u64 hw_nmi_get_sample_period(void)
+{
+        return (u64)(cpu_khz) * 1000 * 60;
+}
+
+#ifdef ARCH_HAS_NMI_WATCHDOG
+void arch_trigger_all_cpu_backtrace(void)
+{
+        int i;
+
+        cpumask_copy(to_cpumask(backtrace_mask), cpu_online_mask);
+
+        printk(KERN_INFO "sending NMI to all CPUs:\n");
+        apic->send_IPI_all(NMI_VECTOR);
+
+        /* Wait for up to 10 seconds for all CPUs to do the backtrace */
+        for (i = 0; i < 10 * 1000; i++) {
+                if (cpumask_empty(to_cpumask(backtrace_mask)))
+                        break;
+                mdelay(1);
+        }
+}
+
+static int __kprobes
+arch_trigger_all_cpu_backtrace_handler(struct notifier_block *self,
+                         unsigned long cmd, void *__args)
+{
+        struct die_args *args = __args;
+        struct pt_regs *regs;
+        int cpu = smp_processor_id();
+
+        switch (cmd) {
+        case DIE_NMI:
+        case DIE_NMI_IPI:
+                break;
+
+        default:
+                return NOTIFY_DONE;
+        }
+
+        regs = args->regs;
+
+        if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
+                static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
+
+                arch_spin_lock(&lock);
+                printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);
+                show_regs(regs);
+                dump_stack();
+                arch_spin_unlock(&lock);
+                cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
+                return NOTIFY_STOP;
+        }
+
+        return NOTIFY_DONE;
+}
+
+static __read_mostly struct notifier_block backtrace_notifier = {
+        .notifier_call          = arch_trigger_all_cpu_backtrace_handler,
+        .next                   = NULL,
+        .priority               = 1
+};
+
+static int __init register_trigger_all_cpu_backtrace(void)
+{
+        register_die_notifier(&backtrace_notifier);
+        return 0;
+}
+early_initcall(register_trigger_all_cpu_backtrace);
+#endif
+
+/* STUB calls to mimic old nmi_watchdog behaviour */
+#if defined(CONFIG_X86_LOCAL_APIC)
+unsigned int nmi_watchdog = NMI_NONE;
+EXPORT_SYMBOL(nmi_watchdog);
+void acpi_nmi_enable(void) { return; }
+void acpi_nmi_disable(void) { return; }
+#endif
+atomic_t nmi_active = ATOMIC_INIT(0);           /* oprofile uses this */
+EXPORT_SYMBOL(nmi_active);
+int unknown_nmi_panic;
+void cpu_nmi_set_wd_enabled(void) { return; }
+void stop_apic_nmi_watchdog(void *unused) { return; }
+void setup_apic_nmi_watchdog(void *unused) { return; }
+int __init check_nmi_watchdog(void) { return 0; }
diff --git a/arch/x86/kernel/apic/nmi.c b/arch/x86/kernel/apic/nmi.c
index 1edaf15c0b8e..a43f71cb30f8 100644
--- a/arch/x86/kernel/apic/nmi.c
+++ b/arch/x86/kernel/apic/nmi.c
@@ -401,13 +401,6 @@ nmi_watchdog_tick(struct pt_regs *regs, unsigned reason)
         int cpu = smp_processor_id();
         int rc = 0;
 
-        /* check for other users first */
-        if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
-                        == NOTIFY_STOP) {
-                rc = 1;
-                touched = 1;
-        }
-
         sum = get_timer_irqs(cpu);
 
         if (__get_cpu_var(nmi_touch)) {
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 725ef4d17cd5..60788dee0f8a 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -392,7 +392,13 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
                 if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 2, SIGINT)
                                                                 == NOTIFY_STOP)
                         return;
+
 #ifdef CONFIG_X86_LOCAL_APIC
+                if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
+                                                        == NOTIFY_STOP)
+                        return;
+
+#ifndef CONFIG_LOCKUP_DETECTOR
                 /*
                  * Ok, so this is none of the documented NMI sources,
                  * so it must be the NMI watchdog.
@@ -400,6 +406,7 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
                 if (nmi_watchdog_tick(regs, reason))
                         return;
                 if (!do_nmi_callback(regs, cpu))
+#endif /* !CONFIG_LOCKUP_DETECTOR */
                         unknown_nmi_error(reason, regs);
 #else
                 unknown_nmi_error(reason, regs);