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ARM: imx6q: Fixup RCU usage for cpuidle

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The commit eb1f00237a ("lockdep,trace: Expose tracepoints"), started to
expose us for tracepoints. For imx6q cpuidle, this leads to an RCU splat
according to below.

[6.870684] [<c0db7690>] (_raw_spin_lock) from [<c011f6a4>] (imx6q_enter_wait+0x18/0x9c)
[6.878846] [<c011f6a4>] (imx6q_enter_wait) from [<c09abfb0>] (cpuidle_enter_state+0x168/0x5e4)

To fix the problem, let's assign the corresponding idlestate->flags the
CPUIDLE_FLAG_RCU_IDLE bit, which enables us to call rcu_idle_enter|exit()
at the proper point.

Reported-by: Dong Aisheng <aisheng.dong@nxp.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Ulf Hansson 2020-09-30 13:20:23 +02:00 committed by Rafael J. Wysocki
parent eac53b3e30
commit 1a67b9263e
1 changed files with 3 additions and 1 deletions
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4
arch/arm/mach-imx/cpuidle-imx6q.c
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@ -24,7 +24,9 @@ static int imx6q_enter_wait(struct cpuidle_device *dev,
imx6_set_lpm(WAIT_UNCLOCKED);
raw_spin_unlock(&cpuidle_lock);
rcu_idle_enter();
cpu_do_idle();
rcu_idle_exit();
raw_spin_lock(&cpuidle_lock);
if (num_idle_cpus-- == num_online_cpus())
@ -44,7 +46,7 @@ static struct cpuidle_driver imx6q_cpuidle_driver = {
{
.exit_latency = 50,
.target_residency = 75,
.flags = CPUIDLE_FLAG_TIMER_STOP,
.flags = CPUIDLE_FLAG_TIMER_STOP | CPUIDLE_FLAG_RCU_IDLE,
.enter = imx6q_enter_wait,
.name = "WAIT",
.desc = "Clock off",