ARM: 9423/1: vfp: Provide vfp_state_hold() for VFP locking.

Browse source

kernel_neon_begin() uses local_bh_disable() to ensure exclusive access
to the VFP unit. This is broken on PREEMPT_RT because a BH disabled
section remains preemptible on PREEMPT_RT.

Introduce vfp_state_hold() which uses local_bh_disable() and
preempt_disable() on PREEMPT_RT. Since softirqs are processed always in
thread context, disabling preemption is enough to ensure that the
current context won't get interrupted by something that is using the
VFP. Use it in kernel_neon_begin().

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

...

This commit is contained in:

Sebastian Andrzej Siewior 2024-10-02 17:15:32 +01:00 • committed by Russell King (Oracle)

parent ad8d1e323d

commit f26bdbe1fa

1 changed files with 30 additions and 2 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

32

arch/arm/vfp/vfpmodule.c

View file