+ /* Switch to the irq stack to handle this */
+ curtp = current_thread_info();
+ irqtp = hardirq_ctx[smp_processor_id()];
+
+ if (curtp == irqtp) {
+ /* We're already on the irq stack, just handle it */
+ generic_handle_irq(irq);
+ return;
+ }
+
+ desc = irq_desc + irq;
+ saved_sp_limit = current->thread.ksp_limit;
+
+ irqtp->task = curtp->task;
+ irqtp->flags = 0;
+
+ /* Copy the softirq bits in preempt_count so that the
+ * softirq checks work in the hardirq context. */
+ irqtp->preempt_count = (irqtp->preempt_count & ~SOFTIRQ_MASK) |
+ (curtp->preempt_count & SOFTIRQ_MASK);
+
+ current->thread.ksp_limit = (unsigned long)irqtp +
+ _ALIGN_UP(sizeof(struct thread_info), 16);
+
+ call_handle_irq(irq, desc, irqtp, desc->handle_irq);
+ current->thread.ksp_limit = saved_sp_limit;
+ irqtp->task = NULL;
+
+ /* Set any flag that may have been set on the
+ * alternate stack
+ */
+ if (irqtp->flags)
+ set_bits(irqtp->flags, &curtp->flags);
+}
+#else
+static inline void handle_one_irq(unsigned int irq)
+{
+ generic_handle_irq(irq);
+}
+#endif