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Subject[PATCH v2 2/5] cpuidle: psci: Mark as PREEMPT_RT safe
Date
The PSCI cpuidle power domain in power_off callback uses
__this_cpu_write() so it is PREEMPT_RT safe. This allows to use it in
Realtime kernels and solves errors like:

BUG: scheduling while atomic: swapper/2/0/0x00000002
Hardware name: Qualcomm Technologies, Inc. Robotics RB5 (DT)
Call trace:
dump_backtrace.part.0+0xe0/0xf0
show_stack+0x18/0x40
dump_stack_lvl+0x68/0x84
dump_stack+0x18/0x34
__schedule_bug+0x60/0x80
__schedule+0x628/0x800
schedule_rtlock+0x28/0x5c
rtlock_slowlock_locked+0x360/0xd30
rt_spin_lock+0x88/0xb0
genpd_lock_nested_spin+0x1c/0x30
genpd_power_off.part.0.isra.0+0x20c/0x2a0
genpd_runtime_suspend+0x150/0x2bc
__rpm_callback+0x48/0x170
rpm_callback+0x6c/0x7c
rpm_suspend+0x108/0x660
__pm_runtime_suspend+0x4c/0x8c
__psci_enter_domain_idle_state.constprop.0+0x54/0xe0
psci_enter_domain_idle_state+0x18/0x2c
cpuidle_enter_state+0x8c/0x4e0
cpuidle_enter+0x38/0x50
do_idle+0x248/0x2f0
cpu_startup_entry+0x24/0x30
secondary_start_kernel+0x130/0x154
__secondary_switched+0xb0/0xb4

Cc: Adrien Thierry <athierry@redhat.com>
Cc: Brian Masney <bmasney@redhat.com>
Cc: linux-rt-users@vger.kernel.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
drivers/cpuidle/cpuidle-psci-domain.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/cpuidle/cpuidle-psci-domain.c b/drivers/cpuidle/cpuidle-psci-domain.c
index c80cf9ddabd8..d15a91fb7048 100644
--- a/drivers/cpuidle/cpuidle-psci-domain.c
+++ b/drivers/cpuidle/cpuidle-psci-domain.c
@@ -62,7 +62,8 @@ static int psci_pd_init(struct device_node *np, bool use_osi)
if (!pd_provider)
goto free_pd;

- pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN;
+ pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_RT_SAFE | \
+ GENPD_FLAG_CPU_DOMAIN;

/* Allow power off when OSI has been successfully enabled. */
if (use_osi)
--
2.34.1
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