1 files changed, 53 insertions, 19 deletions

diff --git a/arch/sparc/kernel/nmi.c b/arch/sparc/kernel/nmi.c
index b75bf502cd42..378eb53e0776 100644
--- a/arch/sparc/kernel/nmi.c
+++ b/arch/sparc/kernel/nmi.c
@@ -19,6 +19,7 @@
 #include <linux/delay.h>
 #include <linux/smp.h>
 
+#include <asm/perf_counter.h>
 #include <asm/ptrace.h>
 #include <asm/local.h>
 #include <asm/pcr.h>
@@ -31,13 +32,19 @@
  * level 14 as our IRQ off level.
  */
 
-static int nmi_watchdog_active;
 static int panic_on_timeout;
 
-int nmi_usable;
-EXPORT_SYMBOL_GPL(nmi_usable);
+/* nmi_active:
+ * >0: the NMI watchdog is active, but can be disabled
+ * <0: the NMI watchdog has not been set up, and cannot be enabled
+ *  0: the NMI watchdog is disabled, but can be enabled
+ */
+atomic_t nmi_active = ATOMIC_INIT(0);           /* oprofile uses this */
+EXPORT_SYMBOL(nmi_active);
 
 static unsigned int nmi_hz = HZ;
+static DEFINE_PER_CPU(short, wd_enabled);
+static int endflag __initdata;
 
 static DEFINE_PER_CPU(unsigned int, last_irq_sum);
 static DEFINE_PER_CPU(local_t, alert_counter);
@@ -45,7 +52,7 @@ static DEFINE_PER_CPU(int, nmi_touch);
 
 void touch_nmi_watchdog(void)
 {
-        if (nmi_watchdog_active) {
+        if (atomic_read(&nmi_active)) {
                 int cpu;
 
                 for_each_present_cpu(cpu) {
@@ -78,6 +85,7 @@ static void die_nmi(const char *str, struct pt_regs *regs, int do_panic)
         if (do_panic || panic_on_oops)
                 panic("Non maskable interrupt");
 
+        nmi_exit();
         local_irq_enable();
         do_exit(SIGBUS);
 }
@@ -92,6 +100,8 @@ notrace __kprobes void perfctr_irq(int irq, struct pt_regs *regs)
 
         local_cpu_data().__nmi_count++;
 
+        nmi_enter();
+
         if (notify_die(DIE_NMI, "nmi", regs, 0,
                        pt_regs_trap_type(regs), SIGINT) == NOTIFY_STOP)
                 touched = 1;
@@ -110,10 +120,12 @@ notrace __kprobes void perfctr_irq(int irq, struct pt_regs *regs)
                 __get_cpu_var(last_irq_sum) = sum;
                 local_set(&__get_cpu_var(alert_counter), 0);
         }
-        if (nmi_usable) {
+        if (__get_cpu_var(wd_enabled)) {
                 write_pic(picl_value(nmi_hz));
                 pcr_ops->write(pcr_enable);
         }
+
+        nmi_exit();
 }
 
 static inline unsigned int get_nmi_count(int cpu)
@@ -121,8 +133,6 @@ static inline unsigned int get_nmi_count(int cpu)
         return cpu_data(cpu).__nmi_count;
 }
 
-static int endflag __initdata;
-
 static __init void nmi_cpu_busy(void *data)
 {
         local_irq_enable_in_hardirq();
@@ -143,12 +153,15 @@ static void report_broken_nmi(int cpu, int *prev_nmi_count)
         printk(KERN_WARNING
                 "and attach the output of the 'dmesg' command.\n");
 
-        nmi_usable = 0;
+        per_cpu(wd_enabled, cpu) = 0;
+        atomic_dec(&nmi_active);
 }
 
-static void stop_watchdog(void *unused)
+void stop_nmi_watchdog(void *unused)
 {
         pcr_ops->write(PCR_PIC_PRIV);
+        __get_cpu_var(wd_enabled) = 0;
+        atomic_dec(&nmi_active);
 }
 
 static int __init check_nmi_watchdog(void)
@@ -156,6 +169,9 @@ static int __init check_nmi_watchdog(void)
         unsigned int *prev_nmi_count;
         int cpu, err;
 
+        if (!atomic_read(&nmi_active))
+                return 0;
+
         prev_nmi_count = kmalloc(nr_cpu_ids * sizeof(unsigned int), GFP_KERNEL);
         if (!prev_nmi_count) {
                 err = -ENOMEM;
@@ -172,12 +188,15 @@ static int __init check_nmi_watchdog(void)
         mdelay((20 * 1000) / nmi_hz); /* wait 20 ticks */
 
         for_each_online_cpu(cpu) {
+                if (!per_cpu(wd_enabled, cpu))
+                        continue;
                 if (get_nmi_count(cpu) - prev_nmi_count[cpu] <= 5)
                         report_broken_nmi(cpu, prev_nmi_count);
         }
         endflag = 1;
-        if (!nmi_usable) {
+        if (!atomic_read(&nmi_active)) {
                 kfree(prev_nmi_count);
+                atomic_set(&nmi_active, -1);
                 err = -ENODEV;
                 goto error;
         }
@@ -188,12 +207,26 @@ static int __init check_nmi_watchdog(void)
         kfree(prev_nmi_count);
         return 0;
 error:
-        on_each_cpu(stop_watchdog, NULL, 1);
+        on_each_cpu(stop_nmi_watchdog, NULL, 1);
         return err;
 }
 
-static void start_watchdog(void *unused)
+void start_nmi_watchdog(void *unused)
 {
+        __get_cpu_var(wd_enabled) = 1;
+        atomic_inc(&nmi_active);
+
+        pcr_ops->write(PCR_PIC_PRIV);
+        write_pic(picl_value(nmi_hz));
+
+        pcr_ops->write(pcr_enable);
+}
+
+static void nmi_adjust_hz_one(void *unused)
+{
+        if (!__get_cpu_var(wd_enabled))
+                return;
+
         pcr_ops->write(PCR_PIC_PRIV);
         write_pic(picl_value(nmi_hz));
 
@@ -203,13 +236,13 @@ static void start_watchdog(void *unused)
 void nmi_adjust_hz(unsigned int new_hz)
 {
         nmi_hz = new_hz;
-        on_each_cpu(start_watchdog, NULL, 1);
+        on_each_cpu(nmi_adjust_hz_one, NULL, 1);
 }
 EXPORT_SYMBOL_GPL(nmi_adjust_hz);
 
 static int nmi_shutdown(struct notifier_block *nb, unsigned long cmd, void *p)
 {
-        on_each_cpu(stop_watchdog, NULL, 1);
+        on_each_cpu(stop_nmi_watchdog, NULL, 1);
         return 0;
 }
 
@@ -221,18 +254,19 @@ int __init nmi_init(void)
 {
         int err;
 
-        nmi_usable = 1;
-
-        on_each_cpu(start_watchdog, NULL, 1);
+        on_each_cpu(start_nmi_watchdog, NULL, 1);
 
         err = check_nmi_watchdog();
         if (!err) {
                 err = register_reboot_notifier(&nmi_reboot_notifier);
                 if (err) {
-                        nmi_usable = 0;
-                        on_each_cpu(stop_watchdog, NULL, 1);
+                        on_each_cpu(stop_nmi_watchdog, NULL, 1);
+                        atomic_set(&nmi_active, -1);
                 }
         }
+        if (!err)
+                init_hw_perf_counters();
+
         return err;
 }