[ARM异常]-SPIs(共享中断)routing到指定CPU的方法

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原理介绍：

废话不多说，看图，看懂的给赞！

内核没有提供指定SPIs中断到特定cpu的接口。那代码我们就胡乱的看一下吧

static int gic_set_affinity(struct irq_data *d, const struct cpumask *mask_val,
                            bool force)
{
        unsigned int cpu = cpumask_any_and(mask_val, cpu_online_mask);
        struct irq_desc *desc = container_of(d, struct irq_desc, irq_data);
        void __iomem *reg;
        int enabled;
        u64 val;

        if (cpu >= nr_cpu_ids)
                return -EINVAL;

        if (gic_irq_in_rdist(d))
                return -EINVAL;

        /* If interrupt was enabled, disable it first */
        enabled = gic_peek_irq(d, GICD_ISENABLER);
        if (enabled)
                gic_mask_irq(d);

        reg = gic_dist_base(d) + GICD_IROUTER + (gic_irq(d) * 8);
        val = gic_mpidr_to_affinity(cpu_logical_map(cpu));

        gic_write_irouter(val, reg);

        /*
         * If the interrupt was enabled, enabled it again. Otherwise,
         * just wait for the distributor to have digested our changes.
         */
        if (enabled)
                gic_unmask_irq(d);
        else
                gic_dist_wait_for_rwp();

        return IRQ_SET_MASK_OK;
}

val = gic_mpidr_to_affinity(cpu_logical_map(cpu)); //读出cpu的id值 gic_write_irouter(val, reg); //将这个值，写入到GICD寄存器