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authorPeter Zijlstra <peterz@infradead.org>2017-09-12 21:36:55 +0200
committerIngo Molnar <mingo@kernel.org>2017-09-14 11:41:03 +0200
commitd0b6e0a8ef24b1b07078ababe5d91bcdf4f4264a (patch)
tree9ffb417f5f94d319352b8e54f94165b82c645762 /kernel/watchdog_hld.c
parent46c1e79fee417f151547aa46fae04ab06cb666f4 (diff)
downloadlinux-d0b6e0a8ef24b1b07078ababe5d91bcdf4f4264a.tar.bz2
watchdog/hardlockup: Provide interface to stop/restart perf events
Provide an interface to stop and restart perf NMI watchdog events on all CPUs. This is only usable during init and especially for handling the perf HT bug on Intel machines. It's safe to use it this way as nothing can start/stop the NMI watchdog in parallel. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Ulrich Obergfell <uobergfe@redhat.com> Link: http://lkml.kernel.org/r/20170912194146.167649596@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/watchdog_hld.c')
-rw-r--r--kernel/watchdog_hld.c41
1 files changed, 41 insertions, 0 deletions
diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c
index 3a09ea1b1d3d..c9586ebc2e98 100644
--- a/kernel/watchdog_hld.c
+++ b/kernel/watchdog_hld.c
@@ -261,3 +261,44 @@ void watchdog_nmi_disable(unsigned int cpu)
firstcpu_err = 0;
}
}
+
+/**
+ * hardlockup_detector_perf_stop - Globally stop watchdog events
+ *
+ * Special interface for x86 to handle the perf HT bug.
+ */
+void __init hardlockup_detector_perf_stop(void)
+{
+ int cpu;
+
+ lockdep_assert_cpus_held();
+
+ for_each_online_cpu(cpu) {
+ struct perf_event *event = per_cpu(watchdog_ev, cpu);
+
+ if (event)
+ perf_event_disable(event);
+ }
+}
+
+/**
+ * hardlockup_detector_perf_restart - Globally restart watchdog events
+ *
+ * Special interface for x86 to handle the perf HT bug.
+ */
+void __init hardlockup_detector_perf_restart(void)
+{
+ int cpu;
+
+ lockdep_assert_cpus_held();
+
+ if (!(watchdog_enabled & NMI_WATCHDOG_ENABLED))
+ return;
+
+ for_each_online_cpu(cpu) {
+ struct perf_event *event = per_cpu(watchdog_ev, cpu);
+
+ if (event)
+ perf_event_enable(event);
+ }
+}