Re: [PATCH 3.17-rc4 v7 4/6] irqchip: gic: Add support for IPI FIQ

[Russell King - ARM Linux]

On Wed, Sep 17, 2014 at 09:10:16AM -0700, Daniel Thompson wrote:
> @@ -604,8 +731,19 @@ static void gic_raise_softirq(const struct cpumask *mask, unsigned int irq)
>  {
>  	int cpu;
>  	unsigned long flags, map = 0;
> +	unsigned long softint;
>  
> -	raw_spin_lock_irqsave(&irq_controller_lock, flags);
> +	/*
> +	 * The locking in this function ensures we don't use stale cpu mappings
> +	 * and thus we never route an IPI to the wrong physical core during a
> +	 * big.LITTLE switch. The switch code takes both of these locks meaning
> +	 * we can choose whichever lock is safe to use from our current calling
> +	 * context.
> +	 */
> +	if (in_nmi())
> +		raw_spin_lock(&fiq_safe_migration_lock);
> +	else
> +		raw_spin_lock_irqsave(&irq_controller_lock, flags);

BTW, I see this code is still here...

-- 
FTTC broadband for 0.8mile line: currently at 9.5Mbps down 400kbps up
according to speedtest.net.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/