45 lines
1.4 KiB
Diff
45 lines
1.4 KiB
Diff
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Fri, 19 May 2023 16:57:30 +0200
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Subject: [PATCH 2/4] ARM: vfp: Use vfp_lock() in vfp_sync_hwstate().
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.11/older/patches-6.11-rt7.tar.xz
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vfp_sync_hwstate() uses preempt_disable() followed by local_bh_disable()
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to ensure that it won't get interrupted while checking the VFP state.
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This harms PREEMPT_RT because softirq handling can get preempted and
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local_bh_disable() synchronizes the related section with a sleeping lock
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which does not work with disabled preemption.
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Use the vfp_lock() to synchronize the access.
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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arch/arm/vfp/vfpmodule.c | 9 +++------
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1 file changed, 3 insertions(+), 6 deletions(-)
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--- a/arch/arm/vfp/vfpmodule.c
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+++ b/arch/arm/vfp/vfpmodule.c
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@@ -540,11 +540,9 @@ static inline void vfp_pm_init(void) { }
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*/
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void vfp_sync_hwstate(struct thread_info *thread)
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{
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- unsigned int cpu = get_cpu();
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+ vfp_lock();
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- local_bh_disable();
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-
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- if (vfp_state_in_hw(cpu, thread)) {
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+ if (vfp_state_in_hw(raw_smp_processor_id(), thread)) {
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u32 fpexc = fmrx(FPEXC);
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/*
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@@ -555,8 +553,7 @@ void vfp_sync_hwstate(struct thread_info
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fmxr(FPEXC, fpexc);
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}
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- local_bh_enable();
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- put_cpu();
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+ vfp_unlock();
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}
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/* Ensure that the thread reloads the hardware VFP state on the next use. */
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