vfp_sync_hwstate() uses preempt_disable() followed by local_bh_disable()
to ensure that it won't get interrupted while checking the VFP state.
This harms PREEMPT_RT because softirq handling can get preempted and
local_bh_disable() synchronizes the related section with a sleeping lock
which does not work with disabled preemption.
Use the vfp_lock() to synchronize the access.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
arch/arm/vfp/vfpmodule.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 57f9527d1e50e..543dc7f5a27e3 100644
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -542,11 +542,9 @@ static inline void vfp_pm_init(void) { }
*/
void vfp_sync_hwstate(struct thread_info *thread)
{
- unsigned int cpu = get_cpu();
+ vfp_lock();
- local_bh_disable();
-
- if (vfp_state_in_hw(cpu, thread)) {
+ if (vfp_state_in_hw(raw_smp_processor_id(), thread)) {
u32 fpexc = fmrx(FPEXC);
/*
@@ -557,8 +555,7 @@ void vfp_sync_hwstate(struct thread_info *thread)
fmxr(FPEXC, fpexc);
}
- local_bh_enable();
- put_cpu();
+ vfp_unlock();
}
/* Ensure that the thread reloads the hardware VFP state on the next use. */
--
2.40.1
