update for mooc OS labs

labcodes_answer/lab1_result/kern/init/init.c

@@ -8,9 +8,9 @@
 #include <clock.h>
 #include <intr.h>
 #include <pmm.h>
-
+#include <kmonitor.h>
 int kern_init(void) __attribute__((noreturn));
-
+void grade_backtrace(void);
 static void lab1_switch_test(void);
 
 int
@@ -37,7 +37,7 @@ kern_init(void) {
 
     //LAB1: CAHLLENGE 1 If you try to do it, uncomment lab1_switch_test()
     // user/kernel mode switch test
-    //lab1_switch_test();
+    lab1_switch_test();
 
     /* do nothing */
     while (1);
@@ -84,11 +84,24 @@ lab1_print_cur_status(void) {
 static void
 lab1_switch_to_user(void) {
     //LAB1 CHALLENGE 1 : TODO
+	asm volatile (
+	    "sub $0x8, %%esp \n"
+	    "int %0 \n"
+	    "movl %%ebp, %%esp"
+	    : 
+	    : "i"(T_SWITCH_TOU)
+	);
 }
 
 static void
 lab1_switch_to_kernel(void) {
     //LAB1 CHALLENGE 1 :  TODO
+	asm volatile (
+	    "int %0 \n"
+	    "movl %%ebp, %%esp \n"
+	    : 
+	    : "i"(T_SWITCH_TOK)
+	);
 }
 
 static void