clocksource/arm_arch_timer: Use static_branch_enable_cpuslocked()

Use the new static_branch_enable_cpuslocked() function to switch
the workaround static key on the CPU hotplug path.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20170801080257.5056-5-marc.zyngier@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index aae87c4c546e..c62e71614c75 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -455,7 +455,11 @@ void arch_timer_enable_workaround(const struct arch_timer_erratum_workaround *wa
                         per_cpu(timer_unstable_counter_workaround, i) = wa;
         }
 
-        static_branch_enable(&arch_timer_read_ool_enabled);
+        /*
+         * Use the locked version, as we're called from the CPU
+         * hotplug framework. Otherwise, we end-up in deadlock-land.
+         */
+        static_branch_enable_cpuslocked(&arch_timer_read_ool_enabled);
 
         /*
          * Don't use the vdso fastpath if errata require using the