Messages in this thread | | | Date | Thu, 07 Jan 2016 14:35:46 +0000 | From | Marc Zyngier <> | Subject | Re: [PATCH 4.4-rc5 v22 2/4] irqchip: gic: Make gic_raise_softirq FIQ-safe |
| |
On 20/12/15 20:52, Daniel Thompson wrote: > It is currently possible for FIQ handlers to re-enter gic_raise_softirq() > and lock up. > > gic_raise_softirq() > lock(x); > -~-> FIQ > handle_fiq() > gic_raise_softirq() > lock(x); <-- Lockup > > arch/arm/ uses IPIs to implement arch_irq_work_raise(), thus this issue > renders it difficult for FIQ handlers to safely defer work to less > restrictive calling contexts. > > This patch fixes the problem by converting the cpu_map_migration_lock > into a rwlock making it safe to re-enter the function. > > Note that having made it safe to re-enter gic_raise_softirq() we no > longer need to mask interrupts during gic_raise_softirq() because the > b.L migration is always performed from task context. > > Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Jason Cooper <jason@lakedaemon.net> > Cc: Russell King <linux@arm.linux.org.uk> > Cc: Marc Zyngier <marc.zyngier@arm.com> > Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
M. -- Jazz is not dead. It just smells funny...
| |