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Diffstat (limited to '')
| -rw-r--r-- | debian/patches-rt/0002-ARM-vfp-Use-vfp_lock-in-vfp_sync_hwstate.patch | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/debian/patches-rt/0002-ARM-vfp-Use-vfp_lock-in-vfp_sync_hwstate.patch b/debian/patches-rt/0002-ARM-vfp-Use-vfp_lock-in-vfp_sync_hwstate.patch new file mode 100644 index 000000000..a0d93547c --- /dev/null +++ b/debian/patches-rt/0002-ARM-vfp-Use-vfp_lock-in-vfp_sync_hwstate.patch @@ -0,0 +1,44 @@ +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Fri, 19 May 2023 16:57:30 +0200 +Subject: [PATCH 2/4] ARM: vfp: Use vfp_lock() in vfp_sync_hwstate(). +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +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@linutronix.de> +--- + arch/arm/vfp/vfpmodule.c | 9 +++------ + 1 file changed, 3 insertions(+), 6 deletions(-) + +--- a/arch/arm/vfp/vfpmodule.c ++++ b/arch/arm/vfp/vfpmodule.c +@@ -540,11 +540,9 @@ 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); + + /* +@@ -555,8 +553,7 @@ void vfp_sync_hwstate(struct thread_info + fmxr(FPEXC, fpexc); + } + +- local_bh_enable(); +- put_cpu(); ++ vfp_unlock(); + } + + /* Ensure that the thread reloads the hardware VFP state on the next use. */ |