实验3环境初始化

Makefile里的gdb和之前不一样了！要添加$(QEMUOPTS)，不然会导致没有挂载交换分区。

.vscode/c_cpp_properties.json

@@ -6,7 +6,7 @@
                 "${workspaceFolder}/**",
                 // "${workspaceFolder}/labcodes_answer/**/", 
                 // 由于按顺序搜索，所以如果这样的话搜索到lab1_result中的同名头文件就不会引用到lab2_result中的同名头文件导致错误
-                "${workspaceFolder}/labcodes_answer/lab2_result/kern/mm/"
+                "${workspaceFolder}/labcodes_answer/lab3_result/**/"
             ],
             "defines": [],
             "compilerPath": "/usr/bin/gcc",

.vscode/launch.json

@@ -11,7 +11,7 @@
             "program": "bin/kernel",
             "args": [],
             "stopAtEntry": false,
-            "cwd": "${workspaceFolder}/labcodes_answer/lab2_result",
+            "cwd": "${workspaceFolder}/labcodes_answer/lab3_result",
             "environment": [],
             "externalConsole": false,
             "MIMode": "gdb",

.vscode/tasks.json

@@ -9,7 +9,7 @@
                 "env": {
                     "DISPLAY": ":0",
                 },
-                "cwd": "${workspaceFolder}/labcodes_answer/lab2_result"
+                "cwd": "${workspaceFolder}/labcodes_answer/lab3_result"
             },
             
             "problemMatcher": [

labcodes_answer/lab3_result/Makefile

@@ -210,7 +210,8 @@ endif
 # files for grade script
 
 TARGETS: $(TARGETS)
-
+targets: $(TARGETS)
+all: $(TARGETS)
 .DEFAULT_GOAL := TARGETS
 
 QEMUOPTS = -hda $(UCOREIMG) -drive file=$(SWAPIMG),media=disk,cache=writeback
@@ -225,7 +226,8 @@ qemu-nox: $(UCOREIMG) $(SWAPIMG)
 	$(V)$(QEMU) -serial mon:stdio $(QEMUOPTS) -nographic
 
 TERMINAL := gnome-terminal
-
+gdb: $(UCOREIMG) $(SWAPIMG)
+	$(V)$(QEMU) -S -s -parallel stdio $(QEMUOPTS) -serial null
 debug: $(UCOREIMG) $(SWAPIMG)
 	$(V)$(QEMU) -S -s -parallel stdio $(QEMUOPTS) -serial null &
 	$(V)sleep 2

labcodes_answer/lab3_result/kern/mm/vmm.c

@@ -260,13 +260,32 @@ check_pgfault(void) {
         *(char *)(addr + i) = i;
         sum += i;
     }
+
+    for (i = 0; i < 100; i ++) {
+        	// 获取页目录项和页表项
+        	    pte_t *pte = get_pte(pgdir, addr + i, 0);
+        	    if (pte != NULL && (*pte & PTE_P)) {
+        	        // 检查访问位
+        	        if (*pte & PTE_A) {
+        	            // A 位已置位
+        	            cprintf("Access bit is set.\n");
+        	        } else {
+        	            // A 位未置位
+        	            cprintf("Access bit is not set.\n");
+        	        }
+        	    } else {
+        	        // 页表项不存在或未呈现
+        	        cprintf("PTE not present.\n");
+        	    }
+            }
+
     for (i = 0; i < 100; i ++) {
         sum -= *(char *)(addr + i);
     }
     assert(sum == 0);
 
     page_remove(pgdir, ROUNDDOWN(addr, PGSIZE));
-    free_page(pde2page(pgdir[0]));
+    free_page(pa2page(pgdir[0]));
     pgdir[0] = 0;
 
     mm->pgdir = NULL;