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-rw-r--r--kernel/watchdog.c67
1 files changed, 66 insertions, 1 deletions
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 10947c835079..237990e8d345 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -208,7 +208,13 @@ void __weak watchdog_hardlockup_enable(unsigned int cpu) { }
void __weak watchdog_hardlockup_disable(unsigned int cpu) { }
-/* Return 0, if a hardlockup watchdog is available. Error code otherwise */
+/*
+ * Watchdog-detector specific API.
+ *
+ * Return 0 when hardlockup watchdog is available, negative value otherwise.
+ * Note that the negative value means that a delayed probe might
+ * succeed later.
+ */
int __weak __init watchdog_hardlockup_probe(void)
{
/*
@@ -954,6 +960,62 @@ static void __init watchdog_sysctl_init(void)
#define watchdog_sysctl_init() do { } while (0)
#endif /* CONFIG_SYSCTL */
+static void __init lockup_detector_delay_init(struct work_struct *work);
+static bool allow_lockup_detector_init_retry __initdata;
+
+static struct work_struct detector_work __initdata =
+ __WORK_INITIALIZER(detector_work, lockup_detector_delay_init);
+
+static void __init lockup_detector_delay_init(struct work_struct *work)
+{
+ int ret;
+
+ ret = watchdog_hardlockup_probe();
+ if (ret) {
+ pr_info("Delayed init of the lockup detector failed: %d\n", ret);
+ pr_info("Hard watchdog permanently disabled\n");
+ return;
+ }
+
+ allow_lockup_detector_init_retry = false;
+
+ watchdog_hardlockup_available = true;
+ lockup_detector_setup();
+}
+
+/*
+ * lockup_detector_retry_init - retry init lockup detector if possible.
+ *
+ * Retry hardlockup detector init. It is useful when it requires some
+ * functionality that has to be initialized later on a particular
+ * platform.
+ */
+void __init lockup_detector_retry_init(void)
+{
+ /* Must be called before late init calls */
+ if (!allow_lockup_detector_init_retry)
+ return;
+
+ schedule_work(&detector_work);
+}
+
+/*
+ * Ensure that optional delayed hardlockup init is proceed before
+ * the init code and memory is freed.
+ */
+static int __init lockup_detector_check(void)
+{
+ /* Prevent any later retry. */
+ allow_lockup_detector_init_retry = false;
+
+ /* Make sure no work is pending. */
+ flush_work(&detector_work);
+
+ return 0;
+
+}
+late_initcall_sync(lockup_detector_check);
+
void __init lockup_detector_init(void)
{
if (tick_nohz_full_enabled())
@@ -964,6 +1026,9 @@ void __init lockup_detector_init(void)
if (!watchdog_hardlockup_probe())
watchdog_hardlockup_available = true;
+ else
+ allow_lockup_detector_init_retry = true;
+
lockup_detector_setup();
watchdog_sysctl_init();
}