[RFC PATCH 23/23] watchdog/hardlockup: Activate the HPET-based lockup detector

[Ricardo Neri]

Now that the implementation of the HPET-based hardlockup detector is
complete, enable it. It will be used only if it can be initialized
successfully. Otherwise, the perf-based detector will be used.

Cc: Ashok Raj <ashok.raj at intel.com>
Cc: Andi Kleen <andi.kleen at intel.com>
Cc: Tony Luck <tony.luck at intel.com>
Cc: Borislav Petkov <bp at suse.de>
Cc: Jacob Pan <jacob.jun.pan at intel.com>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki at intel.com>
Cc: Don Zickus <dzickus at redhat.com>
Cc: Nicholas Piggin <npiggin at gmail.com>
Cc: Michael Ellerman <mpe at ellerman.id.au>
Cc: Frederic Weisbecker <frederic at kernel.org>
Cc: Alexei Starovoitov <ast at kernel.org>
Cc: Babu Moger <babu.moger at oracle.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
Cc: Masami Hiramatsu <mhiramat at kernel.org>
Cc: Peter Zijlstra <peterz at infradead.org>
Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: Philippe Ombredanne <pombredanne at nexb.com>
Cc: Colin Ian King <colin.king at canonical.com>
Cc: Byungchul Park <byungchul.park at lge.com>
Cc: "Paul E. McKenney" <paulmck at linux.vnet.ibm.com>
Cc: "Luis R. Rodriguez" <mcgrof at kernel.org>
Cc: Waiman Long <longman at redhat.com>
Cc: Josh Poimboeuf <jpoimboe at redhat.com>
Cc: Randy Dunlap <rdunlap at infradead.org>
Cc: Davidlohr Bueso <dave at stgolabs.net>
Cc: Christoffer Dall <cdall at linaro.org>
Cc: Marc Zyngier <marc.zyngier at arm.com>
Cc: Kai-Heng Feng <kai.heng.feng at canonical.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>
Cc: David Rientjes <rientjes at google.com>
Cc: "Ravi V. Shankar" <ravi.v.shankar at intel.com>
Cc: x86 at kernel.org
Cc: iommu at lists.linux-foundation.org
Signed-off-by: Ricardo Neri <ricardo.neri-calderon at linux.intel.com>
---
 kernel/watchdog.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index b5ce6e4..e2cc6c0 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -149,6 +149,21 @@ int __weak __init watchdog_nmi_probe(void)
 {
 	int ret = -ENODEV;
 
+	/*
+	 * Try first with the HPET hardlockup detector. It will only
+	 * succeed if selected at build time and the nmi_watchdog
+	 * command-line parameter is configured. This ensure that the
+	 * perf-based detector is used by default, if selected at
+	 * build time.
+	 */
+	if (IS_ENABLED(CONFIG_HARDLOCKUP_DETECTOR_HPET))
+		ret = hardlockup_detector_hpet_ops.init();
+
+	if (!ret) {
+		nmi_wd_ops = &hardlockup_detector_hpet_ops;
+		return ret;
+	}
+
 	if (IS_ENABLED(CONFIG_HARDLOCKUP_DETECTOR_PERF))
 		ret = hardlockup_detector_perf_ops.init();
 
-- 
2.7.4