图5-1：内核初始化

调用两次parse_args(一次是直接调用， 而另外一次是通过parse_early_param间接调用)以处理引导加载程序(bootloader, 如LILO或GRUB)
在引导期间传给内核的配置参数。

硬中断和软中断分别由init_IRQ和softirq_init做初始化。

内核子系统及内建的设备驱动程序由do_initcall初始化。

由设备驱动在总线(pci,usb)的协调下完成，主要分配中断号和i/o地址。

在设备可用前需要配置一些参数，如ip地址

与设备相关，如流量控制

1:  static inline int __must_check

2:  request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags,

3:           const char *name, void *dev)

4:  {

5:       return request_threaded_irq(irq, handler, NULL, flags, name, dev);

6:  }

1:  extern void free_irq(unsigned int, void *);

 1:  /*

 2:   *   Initialize the DEV module. At boot time this walks the device list and

 3:   *   unhooks any devices that fail to initialise (normally hardware not

 4:   *   present) and leaves us with a valid list of present and active devices.

 5:   *

 6:   */

 7:

 8:  /*

 9:   *       This is called single threaded during boot, so no need

10:   *       to take the rtnl semaphore.

11:   */

12:  static int __init net_dev_init(void)

13:  {

14:       int i, rc = -ENOMEM;

15:

16:       BUG_ON(!dev_boot_phase);

17:

18:       if (dev_proc_init())

19:           goto out;

20:

21:       if (netdev_kobject_init())

22:           goto out;

23:

24:       INIT_LIST_HEAD(&ptype_all);

25:       for (i = ; i < PTYPE_HASH_SIZE; i++)

26:           INIT_LIST_HEAD(&ptype_base[i]);

27:

28:       if (register_pernet_subsys(&netdev_net_ops))

29:           goto out;

30:

31:       /*

32:        *  Initialise the packet receive queues.

33:        */

34:

35:       for_each_possible_cpu(i) {

36:           struct softnet_data *sd = &per_cpu(softnet_data, i);

37:

38:           memset(sd, , sizeof(*sd));

39:           skb_queue_head_init(&sd->input_pkt_queue);

40:           skb_queue_head_init(&sd->process_queue);

41:           sd->completion_queue = NULL;

42:           INIT_LIST_HEAD(&sd->poll_list);

43:           sd->output_queue = NULL;

44:           sd->output_queue_tailp = &sd->output_queue;

45:  #ifdef CONFIG_RPS

46:           sd->csd.func = rps_trigger_softirq;

47:           sd->csd.info = sd;

48:           sd->csd.flags = ;

49:           sd->cpu = i;

50:  #endif

51:

52:           sd->backlog.poll = process_backlog;

53:           sd->backlog.weight = weight_p;

54:           sd->backlog.gro_list = NULL;

55:           sd->backlog.gro_count = ;

56:       }

57:

58:       dev_boot_phase = ;

59:

60:       /* The loopback device is special if any other network devices

61:        * is present in a network namespace the loopback device must

62:        * be present. Since we now dynamically allocate and free the

63:        * loopback device ensure this invariant is maintained by

64:        * keeping the loopback device as the first device on the

65:        * list of network devices.  Ensuring the loopback devices

66:        * is the first device that appears and the last network device

67:        * that disappears.

68:        */

69:       if (register_pernet_device(&loopback_net_ops))

70:           goto out;

71:

72:       if (register_pernet_device(&default_device_ops))

73:           goto out;

74:

75:       open_softirq(NET_TX_SOFTIRQ, net_tx_action);

76:       open_softirq(NET_RX_SOFTIRQ, net_rx_action);

77:

78:       hotcpu_notifier(dev_cpu_callback, );

79:       dst_init();

80:       dev_mcast_init();

81:       rc = ;

82:  out:

83:       return rc;

84:  }

85:

86:  subsys_initcall(net_dev_init);

Footnotes: