Re: [PATCH 2/5] irqchip: gicv3-its: zero itt before handling to hardware

From: Marc Zyngier
Date: Fri Jan 30 2015 - 14:25:09 EST


On 30/01/15 07:46, Yun Wu wrote:
> Some kind of brain-dead implementations chooses to insert ITEes in
> rapid sequence of disabled ITEes, and an un-zeroed ITT will confuse
> ITS on judging whether an ITE is really enabled or not. Considering
> the implementations are still supported by the GICv3 architecture,
> in which ITT is not required to be zeroed before being handled to
> hardware, we do the favor in ITS driver.
>
> Signed-off-by: Yun Wu <wuyun.wu@xxxxxxxxxx>
> ---
> drivers/irqchip/irq-gic-v3-its.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
> index a391417..2a08d85 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -1063,7 +1063,7 @@ static struct its_device *its_create_device(struct its_node *its, u32 dev_id,
> nr_ites = max(2UL, roundup_pow_of_two(nvecs));
> sz = nr_ites * its->ite_size;
> sz = max(sz, ITS_ITT_ALIGN) + ITS_ITT_ALIGN - 1;
> - itt = kmalloc(sz, GFP_KERNEL);
> + itt = kzalloc(sz, GFP_KERNEL);
> lpi_map = its_lpi_alloc_chunks(nvecs, &lpi_base, &nr_lpis);
>
> if (!dev || !itt || !lpi_map) {

Fair enough. I suppose this cannot really hurt if we have stupid HW around.

Acked-by: Marc Zyngier <marc.zyngier@xxxxxxx>

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