From: Thomas Gleixner <t...@linutronix.de>
timekeeping suspend/resume calls read_persistent_clock() which takes
rtc_lock. That results in might sleep warnings because at that point
we run with interrupts disabled.
We cannot convert rtc_lock to a raw spinlock as that would trigger
other might sleep warnings.
As a workaround we disable the might sleep warnings by setting
system_state to SYSTEM_SUSPEND before calling sysdev_suspend() and
restoring it to SYSTEM_RUNNING afer sysdev_resume(). There is no lock
contention because hibernate / suspend to RAM is single-CPU at this
point.
In s2idle's case the system_state is set to SYSTEM_SUSPEND before
timekeeping_suspend() which is invoked by the last CPU. In the resume
case it set back to SYSTEM_RUNNING after timekeeping_resume() which is
invoked by the first CPU in the resume case. The other CPUs will block
on tick_freeze_lock.
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
[bigeasy: cover s2idle in tick_freeze() / tick_unfreeze()]
Signed-off-by: Sebastian Andrzej Siewior <bige...@linutronix.de>
---
v1…v2: Moved the s2idle case into tick_freeze()/unfreeze() as suggested
by Rafael (tglx was okay with this).
include/linux/kernel.h | 1 +
kernel/power/hibernate.c | 7 +++++++
kernel/power/suspend.c | 4 ++++
kernel/time/tick-common.c | 2 ++
4 files changed, 14 insertions(+)
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 6a1eb0b0aad9..7aed92624531 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -542,6 +542,7 @@ extern enum system_states {
SYSTEM_HALT,
SYSTEM_POWER_OFF,
SYSTEM_RESTART,
+ SYSTEM_SUSPEND,
} system_state;
/* This cannot be an enum because some may be used in assembly source. */
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 5454cc639a8d..9c85c7822383 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -287,6 +287,8 @@ static int create_image(int platform_mode)
local_irq_disable();
+ system_state = SYSTEM_SUSPEND;
+
error = syscore_suspend();
if (error) {
pr_err("Some system devices failed to power down, aborting
hibernation\n");
@@ -317,6 +319,7 @@ static int create_image(int platform_mode)
syscore_resume();
Enable_irqs:
+ system_state = SYSTEM_RUNNING;
local_irq_enable();
Enable_cpus:
@@ -445,6 +448,7 @@ static int resume_target_kernel(bool platform_mode)
goto Enable_cpus;
local_irq_disable();
+ system_state = SYSTEM_SUSPEND;
error = syscore_suspend();
if (error)
@@ -478,6 +482,7 @@ static int resume_target_kernel(bool platform_mode)
syscore_resume();
Enable_irqs:
+ system_state = SYSTEM_RUNNING;
local_irq_enable();
Enable_cpus:
@@ -563,6 +568,7 @@ int hibernation_platform_enter(void)
goto Enable_cpus;
local_irq_disable();
+ system_state = SYSTEM_SUSPEND;
syscore_suspend();
if (pm_wakeup_pending()) {
error = -EAGAIN;
@@ -575,6 +581,7 @@ int hibernation_platform_enter(void)
Power_up:
syscore_resume();
+ system_state = SYSTEM_RUNNING;
local_irq_enable();
Enable_cpus:
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 4c10be0f4843..5149c77506b3 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -428,6 +428,8 @@ static int suspend_enter(suspend_state_t state, bool
*wakeup)
arch_suspend_disable_irqs();
BUG_ON(!irqs_disabled());
+ system_state = SYSTEM_SUSPEND;
+
error = syscore_suspend();
if (!error) {
*wakeup = pm_wakeup_pending();
@@ -443,6 +445,8 @@ static int suspend_enter(suspend_state_t state, bool
*wakeup)
syscore_resume();
}
+ system_state = SYSTEM_RUNNING;
+
arch_suspend_enable_irqs();
BUG_ON(irqs_disabled());
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index 49edc1c4f3e6..14de3727b18e 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -490,6 +490,7 @@ void tick_freeze(void)
if (tick_freeze_depth == num_online_cpus()) {
trace_suspend_resume(TPS("timekeeping_freeze"),
smp_processor_id(), true);
+ system_state = SYSTEM_SUSPEND;
timekeeping_suspend();
} else {
tick_suspend_local();
@@ -513,6 +514,7 @@ void tick_unfreeze(void)
if (tick_freeze_depth == num_online_cpus()) {
timekeeping_resume();
+ system_state = SYSTEM_RUNNING;
trace_suspend_resume(TPS("timekeeping_freeze"),
smp_processor_id(), false);
} else {
--
2.17.0
