1 /*
 2 * linux-3.9.4/mykernel/mymain.c
 3 * 核心自定義啟動程式碼
 4 */
 5 
 6 #include <linux/types.h>
 7 #include <linux/string.h>
 8 #include <linux/ctypes.h>
 9 #include <linux/tty.h>
10 #include <linux/vmalloc.h>
11 
12 #include "mypcb.h"
13 
14 tPCB task[MAX_TASK_NUM];
15 tPCB* my_current_task = NULL;
 
16 volatile int my_need_sched = 0;
17 
18 void my_process(void);
19 
20 void __init my_start_kernel(void)
21 {
22     int pid = 0;
23     int i;
24     task[pid].pid = pid;
25     task[pid].state = 0; /*-1 暫停, 0 可執行, >0 已停止*/
26     task[pid].task_entry = task[pid].thread.ip = (unsigned long)myprocess;
27
 
     task[pid].thread.sp = (unsigned long)&task[pid].stack[KERNEL_STACK_SIZE - 1];
28     task[pid].next = &task[pid];
29 
30     for (i = 1; i < MAX_TASK_NUM; i++) 
31     {
32         memcpy(&task[i], &task[0], sizeof(tPCB));
33         task[i].pid = i;
34         task[i].state = -1
 
;
35         task[i].thread.sp = (unsigned long)&task[i].stack[KERNEL_STACK_SIZE - 1];
36         task[i].next = task[i - 1].next;
37         task[i - 1].next = &task[i];
38     }
39 
40     pid = 0;
41     my_current_task = &task[pid];
42     asm volatile(
43         "mov %1, %%esp\n\t"    /* 將task[pid].thread.sp載入到[esp] */
44         "pushl %1\n\t"        /* 儲存當前任務堆疊基地址 */
45         "pushl %0\n\t"        /* 儲存當前任務指令地址 */
46         "ret\n\t"            /* 將上1行程式碼儲存的指令地址載入到[eip] */
47         "popl %%ebp\n\t"
48         :
49         : "c" (task[pid].thread.ip),"d" (task[pid].thread.sp)
50         );
51 }
52 
53 void my_process(void)
54 {
55     int i = 0;
56     while (1)
57     {
58         i++;
59         if (i % 10000000 == 0)
60         {
61             printk(KERN_NOTICE "this is process %d -\n", my_current_task->pid);
62             /* 如果需要排程 */
63             if (my_need_sched == 1)
64             {
65                 my_need_sched = 0;
66                 my_schedule();
67             }
68             printk(KERN_NOTICE "this is process %d+\n", my_current_task->pid);
69         }
70     }
71 }