irqchip/loongson-pch-pic: Fix translate callback for DT path

[ Upstream commit c7c0013 ]

In DT path of translate callback, if fwspec->param_count==1
and of_node is non-null, fwspec->param[1] will be accessed,
which is introduced from previous commit bcdd75c
(irqchip/loongson-pch-pic: Add ACPI init support).

Before the patch, for non-null of_node, translate callback
(use irq_domain_translate_twocell()) will return -EINVAL if
fwspec->param_count < 2, so the check in the patch is added.

Fixes: bcdd75c ("irqchip/loongson-pch-pic: Add ACPI init support")
Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn>
Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221022075955.11726-3-lvjianmin@loongson.cn
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/irqchip/irq-loongson-pch-pic.c

@@ -159,6 +159,9 @@ static int pch_pic_domain_translate(struct irq_domain *d,
 		return -EINVAL;
 
 	if (of_node) {
+		if (fwspec->param_count < 2)
+			return -EINVAL;
+
 		*hwirq = fwspec->param[0] + priv->ht_vec_base;
 		*type = fwspec->param[1] & IRQ_TYPE_SENSE_MASK;
 	} else {