armv8a移植遇到的问题。

发布于 2021-06-10 09:49:10 浏览：1366 订阅该版

[tocm]

## 系统环境
armv8-a 64位 4核cortex-a35
移植到rt-smart分支系统中
由于rt没有线程支持aarch64 cortex-a35，因此参考cortex-a72做些相关的改动
当前系统没有开启多核支持

## 问题
移植后开机出现以下日志，出现了以下错误。
![image.png](https://oss-club.rt-thread.org/uploads/20210610/ccf4c6e71b4abc61252a2bb5519ef51b.png)
红框为我额外添加的打印。对应的代码如下
```c
void rt_system_scheduler_start(void)
{
    register struct rt_thread *to_thread;
    rt_ubase_t highest_ready_priority;

to_thread = _get_highest_priority_thread(&highest_ready_priority);

#ifdef RT_USING_SMP
    to_thread->oncpu = rt_hw_cpu_id();
#else
    rt_current_thread = to_thread;
#endif /*RT_USING_SMP*/

rt_schedule_remove_thread(to_thread);
    to_thread->stat = RT_THREAD_RUNNING;

/* switch to new thread */
#ifdef RT_USING_SMP
    rt_hw_context_switch_to((rt_ubase_t)&to_thread->sp, to_thread);
#else
    
    rt_kprintf("[%s, %d]\r\n", __func__, __LINE__);
    
    rt_kprintf("to_thread->name = %s\r\n", to_thread->name);
    rt_kprintf("to_thread->sp = 0x%016X\r\n", to_thread->sp);
    rt_kprintf("to_thread->entry = 0x%016X\r\n", to_thread->entry);
    
    rt_hw_context_switch_to((rt_ubase_t)&to_thread->sp);
    
    rt_kprintf("[%s, %d]\r\n", __func__, __LINE__);
#endif /*RT_USING_SMP*/

/* never come back */
}
```
看起来是rt_hw_context_switch_to跳转到timer线程没有成功。

当前没有查找的思路了，跪求有经验的大佬指导一下可以往下调试的手段，或者方向，谢谢！