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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Wed, 28 Jun 2023 09:36:10 +0200
Subject: [PATCH 3/4] ARM: vfp: Use vfp_lock() in vfp_support_entry().
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.10/older/patches-6.10.2-rt14.tar.xz
vfp_entry() is invoked from exception handler and is fully preemptible.
It uses local_bh_disable() to remain uninterrupted while checking the
VFP state.
This is not working on PREEMPT_RT because local_bh_disable()
synchronizes the relevant section but the context remains fully
preemptible.
Use vfp_lock() for uninterrupted access.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
arch/arm/vfp/vfpmodule.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -708,7 +708,7 @@ static int vfp_support_entry(struct pt_r
if (!user_mode(regs))
return vfp_kmode_exception(regs, trigger);
- local_bh_disable();
+ vfp_lock();
fpexc = fmrx(FPEXC);
/*
@@ -787,7 +787,7 @@ static int vfp_support_entry(struct pt_r
if (!(fpscr & FPSCR_IXE)) {
if (!(fpscr & FPSCR_LENGTH_MASK)) {
pr_debug("not VFP\n");
- local_bh_enable();
+ vfp_unlock();
return -ENOEXEC;
}
fpexc |= FPEXC_DEX;
@@ -797,7 +797,7 @@ bounce: regs->ARM_pc += 4;
VFP_bounce(trigger, fpexc, regs);
}
- local_bh_enable();
+ vfp_unlock();
return 0;
}
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