diff mbox series

[v3,3/4] ARM: vfp: Use vfp_lock() in vfp_support_entry().

Message ID 20230926125502.1127015-4-bigeasy@linutronix.de (mailing list archive)
State New, archived
Headers show
Series ARM: vfp: Introduce vfp_lock() for VFP locking. | expand

Commit Message

Sebastian Andrzej Siewior Sept. 26, 2023, 12:55 p.m. UTC 
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>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm/vfp/vfpmodule.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 3b9360bfc5081..9543f011d0edf 100644
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -708,7 +708,7 @@  static int vfp_support_entry(struct pt_regs *regs, u32 trigger)
 	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_regs *regs, u32 trigger)
 			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;
 }