内核reboot流程

kernel/reboot.c

void kernel_restartchar *cmd)
{
        kernel_restart_preparecmd);
        migrate_to_reboot_cpu);
        syscore_shutdown);
        if !cmd)
                pr_emerg"Restarting system
");
        else
                pr_emerg"Restarting system with command '%s'
", cmd);
        kmsg_dumpKMSG_DUMP_RESTART);
        machine_restartcmd);
}

->reboot命令

->glibc给所有任务发送kill

->内核态kernel_restart)

->kernel_restart_prepare)

->device_shutdown)

-> dev->driver->shutdown) 调用驱动注册的.shutdown钩子

->migrate_to_reboot_cpu) 关闭cpu hotplug

->syscore_shutdown) 里面ops->shutdown，内核相关子系统（比如clk，irq，pm）注册的shutdown

->machine_restart

->local_irq_disable); smp_send_stop); /* Disable interrupts first */

-> 根据 arm_pm_restart是否初始化决定走arm_pm_restartreboot_mode, cmd),如果是这种case，一般会写pm register将whole cpu reset；或 do_kernel_restartcmd);

->do_kernel_restart) 执行注册的restart_handler_list

->BIOS->ATF->芯片复位

from: https://zhuanlan.zhihu.com/p/353452093