watchdog: Add watchdog enable/disable all functions

This patch adds two new functions to enable/disable
the watchdog across all CPUs.

This will be used by the HT PMU bug workaround code to
disable/enable the NMI watchdog across quirk enablement.

Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: bp@alien8.de
Cc: jolsa@redhat.com
Cc: kan.liang@intel.com
Cc: maria.n.dimakopoulou@gmail.com
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1416251225-17721-12-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

include/linux/watchdog.h

@@ -137,4 +137,12 @@ extern int watchdog_init_timeout(struct watchdog_device *wdd,
 extern int watchdog_register_device(struct watchdog_device *);
 extern void watchdog_unregister_device(struct watchdog_device *);
 
+#ifdef CONFIG_HARDLOCKUP_DETECTOR
+void watchdog_nmi_disable_all(void);
+void watchdog_nmi_enable_all(void);
+#else
+static inline void watchdog_nmi_disable_all(void) {}
+static inline void watchdog_nmi_enable_all(void) {}
+#endif
+
 #endif  /* ifndef _LINUX_WATCHDOG_H */

kernel/watchdog.c

@@ -567,9 +567,37 @@ static void watchdog_nmi_disable(unsigned int cpu)
 		cpu0_err = 0;
 	}
 }
+
+void watchdog_nmi_enable_all(void)
+{
+	int cpu;
+
+	if (!watchdog_user_enabled)
+		return;
+
+	get_online_cpus();
+	for_each_online_cpu(cpu)
+		watchdog_nmi_enable(cpu);
+	put_online_cpus();
+}
+
+void watchdog_nmi_disable_all(void)
+{
+	int cpu;
+
+	if (!watchdog_running)
+		return;
+
+	get_online_cpus();
+	for_each_online_cpu(cpu)
+		watchdog_nmi_disable(cpu);
+	put_online_cpus();
+}
 #else
 static int watchdog_nmi_enable(unsigned int cpu) { return 0; }
 static void watchdog_nmi_disable(unsigned int cpu) { return; }
+void watchdog_nmi_enable_all(void) {}
+void watchdog_nmi_disable_all(void) {}
 #endif /* CONFIG_HARDLOCKUP_DETECTOR */
 
 static struct smp_hotplug_thread watchdog_threads = {