Subject: Re: [PATCH] irqchip/ti-sci-inta: fix processing of masked irqs

From: Marc Zyngier <[email-masked]>
Date: Thu, 9 Apr 2020 10:31:44 +0100

On Wed, 8 Apr 2020 22:15:32 +0300
Grygorii Strashko <[email-masked]> wrote:

> The ti_sci_inta_irq_handler() does not take into account INTA IRQs state
> (masked/unmasked) as it uses INTA_STATUS_CLEAR_j register to get INTA IRQs
> status, which provides raw status value.
> This causes hard IRQ handlers to be called or threaded handlers to be
> scheduled many times even if corresponding INTA IRQ is masked.
> Above, first of all, affects the LEVEL interrupts processing and causes
> unexpected behavior up the system stack or crash.
> 
> Fix it by using the Interrupt Masked Status INTA_STATUSM_j register which
> provides masked INTA IRQs status.
> 
> Fixes: 9f1463b86c13 ("irqchip/ti-sci-inta: Add support for Interrupt Aggregator driver")
> Signed-off-by: Grygorii Strashko <[email-masked]>

Given the failure mode, doesn't this deserve a Cc stable?

> ---
>  drivers/irqchip/irq-ti-sci-inta.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/irqchip/irq-ti-sci-inta.c b/drivers/irqchip/irq-ti-sci-inta.c
> index 8f6e6b08eadf..7e3ebf6ed2cd 100644
> --- a/drivers/irqchip/irq-ti-sci-inta.c
> +++ b/drivers/irqchip/irq-ti-sci-inta.c
> @@ -37,6 +37,7 @@
>  #define VINT_ENABLE_SET_OFFSET	0x0
>  #define VINT_ENABLE_CLR_OFFSET	0x8
>  #define VINT_STATUS_OFFSET	0x18
> +#define VINT_STATUS_MASKED_OFFSET	0x20
>  
>  /**
>   * struct ti_sci_inta_event_desc - Description of an event coming to
> @@ -116,7 +117,7 @@ static void ti_sci_inta_irq_handler(struct irq_desc *desc)
>  	chained_irq_enter(irq_desc_get_chip(desc), desc);
>  
>  	val = readq_relaxed(inta->base + vint_desc->vint_id * 0x1000 +
> -			    VINT_STATUS_OFFSET);
> +			    VINT_STATUS_MASKED_OFFSET);
>  
>  	for_each_set_bit(bit, &val, MAX_EVENTS_PER_VINT) {
>  		virq = irq_find_mapping(domain, vint_desc->events[bit].hwirq);

Otherwise queued for post -rc1.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...

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