1 files changed, 43 insertions, 1 deletions

diff --git a/arch/sparc/kernel/nmi.c b/arch/sparc/kernel/nmi.c
index a9973bb4a1b2..95e73c63c99d 100644
--- a/arch/sparc/kernel/nmi.c
+++ b/arch/sparc/kernel/nmi.c
@@ -42,7 +42,7 @@ static int panic_on_timeout;
  */
 atomic_t nmi_active = ATOMIC_INIT(0);           /* oprofile uses this */
 EXPORT_SYMBOL(nmi_active);
-
+static int nmi_init_done;
 static unsigned int nmi_hz = HZ;
 static DEFINE_PER_CPU(short, wd_enabled);
 static int endflag __initdata;
@@ -153,6 +153,8 @@ static void report_broken_nmi(int cpu, int *prev_nmi_count)
 
 void stop_nmi_watchdog(void *unused)
 {
+        if (!__this_cpu_read(wd_enabled))
+                return;
         pcr_ops->write_pcr(0, pcr_ops->pcr_nmi_disable);
         __this_cpu_write(wd_enabled, 0);
         atomic_dec(&nmi_active);
@@ -207,6 +209,9 @@ error:
 
 void start_nmi_watchdog(void *unused)
 {
+        if (__this_cpu_read(wd_enabled))
+                return;
+
         __this_cpu_write(wd_enabled, 1);
         atomic_inc(&nmi_active);
 
@@ -259,6 +264,8 @@ int __init nmi_init(void)
                 }
         }
 
+        nmi_init_done = 1;
+
         return err;
 }
 
@@ -270,3 +277,38 @@ static int __init setup_nmi_watchdog(char *str)
         return 0;
 }
 __setup("nmi_watchdog=", setup_nmi_watchdog);
+
+/*
+ * sparc specific NMI watchdog enable function.
+ * Enables watchdog if it is not enabled already.
+ */
+int watchdog_nmi_enable(unsigned int cpu)
+{
+        if (atomic_read(&nmi_active) == -1) {
+                pr_warn("NMI watchdog cannot be enabled or disabled\n");
+                return -1;
+        }
+
+        /*
+         * watchdog thread could start even before nmi_init is called.
+         * Just Return in that case. Let nmi_init finish the init
+         * process first.
+         */
+        if (!nmi_init_done)
+                return 0;
+
+        smp_call_function_single(cpu, start_nmi_watchdog, NULL, 1);
+
+        return 0;
+}
+/*
+ * sparc specific NMI watchdog disable function.
+ * Disables watchdog if it is not disabled already.
+ */
+void watchdog_nmi_disable(unsigned int cpu)
+{
+        if (atomic_read(&nmi_active) == -1)
+                pr_warn_once("NMI watchdog cannot be enabled or disabled\n");
+        else
+                smp_call_function_single(cpu, stop_nmi_watchdog, NULL, 1);
+}