Commit 1a67b926 authored by Ulf Hansson's avatar Ulf Hansson Committed by Rafael J. Wysocki

ARM: imx6q: Fixup RCU usage for cpuidle

The commit eb1f0023 ("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: default avatarDong Aisheng <aisheng.dong@nxp.com>
Suggested-by: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent eac53b3e
...@@ -24,7 +24,9 @@ static int imx6q_enter_wait(struct cpuidle_device *dev, ...@@ -24,7 +24,9 @@ static int imx6q_enter_wait(struct cpuidle_device *dev,
imx6_set_lpm(WAIT_UNCLOCKED); imx6_set_lpm(WAIT_UNCLOCKED);
raw_spin_unlock(&cpuidle_lock); raw_spin_unlock(&cpuidle_lock);
rcu_idle_enter();
cpu_do_idle(); cpu_do_idle();
rcu_idle_exit();
raw_spin_lock(&cpuidle_lock); raw_spin_lock(&cpuidle_lock);
if (num_idle_cpus-- == num_online_cpus()) if (num_idle_cpus-- == num_online_cpus())
...@@ -44,7 +46,7 @@ static struct cpuidle_driver imx6q_cpuidle_driver = { ...@@ -44,7 +46,7 @@ static struct cpuidle_driver imx6q_cpuidle_driver = {
{ {
.exit_latency = 50, .exit_latency = 50,
.target_residency = 75, .target_residency = 75,
.flags = CPUIDLE_FLAG_TIMER_STOP, .flags = CPUIDLE_FLAG_TIMER_STOP | CPUIDLE_FLAG_RCU_IDLE,
.enter = imx6q_enter_wait, .enter = imx6q_enter_wait,
.name = "WAIT", .name = "WAIT",
.desc = "Clock off", .desc = "Clock off",
......
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