finish exec3.2

lab3/kernel/process/process.c

@@ -247,17 +247,21 @@ void process_create_root(char *bin_name)
 	char *binary = NULL;
 	int ret;
 
+	// 从内存硬盘读取相关文件，使用 CPIO 格式
 	ret = ramdisk_read_file(bin_name, &binary);
 	BUG_ON(ret < 0);
 	BUG_ON(binary == NULL);
 
+	// 创建 PCB 并设置自身 Cap
 	root_process = process_create();
 
+	// 创建主线程与其 Cap
 	thread_cap = thread_create_main(root_process, ROOT_THREAD_STACK_BASE,
 					ROOT_THREAD_STACK_SIZE,
 					ROOT_THREAD_PRIO, TYPE_ROOT,
 					0, binary, bin_name);
 
+	// 将主线程 Cap 加入进程
 	root_thread = obj_get(root_process, thread_cap, TYPE_THREAD);
 	/* Enqueue: put init thread into the ready queue */
 	obj_put(root_thread);

lab3/kernel/process/thread.c

@@ -256,10 +256,12 @@ int thread_create_main(struct process *process, u64 stack_base,
 	u64 stack;
 	u64 pc;
 
+	// 创建虚拟地址空间
 	init_vmspace = obj_get(process, VMSPACE_OBJ_ID, TYPE_VMSPACE);
 	obj_put(init_vmspace);
 
 	/* Allocate and setup a user stack for the init thread */
+	// 创建用户栈 PMO 对象，并设置 Cap
 	stack_pmo = obj_alloc(TYPE_PMO, sizeof(*stack_pmo));
 	if (!stack_pmo) {
 		ret = -ENOMEM;
@@ -272,11 +274,13 @@ int thread_create_main(struct process *process, u64 stack_base,
 		goto out_free_obj_pmo;
 	}
 
+	// 映射线程用户栈
 	ret = vmspace_map_range(init_vmspace, stack_base, stack_size,
 				VMR_READ | VMR_WRITE, stack_pmo);
 	BUG_ON(ret != 0);
 
 	/* init thread */
+	// 初始化线程对象
 	thread = obj_alloc(TYPE_THREAD, sizeof(*thread));
 	if (!thread) {
 		ret = -ENOMEM;
@@ -286,15 +290,19 @@ int thread_create_main(struct process *process, u64 stack_base,
 	/* Fill the parameter of the thread struct */
 	stack = stack_base + stack_size;
 
+	// 加载程序各 ELF 段
 	pc = load_binary(process, init_vmspace, bin_start, &meta);
 
+	// 设置栈
 	prepare_env((char *)phys_to_virt(stack_pmo->start) + stack_size,
 		    stack, &meta, bin_name);
 	stack -= ENV_SIZE_ON_STACK;
 
+	// 创建线程上下文
 	ret = thread_init(thread, process, stack, pc, prio, type, aff);
 	BUG_ON(ret != 0);
 
+	// 取得线程 Cap
 	thread_cap = cap_alloc(process, thread, 0);
 	if (thread_cap < 0) {
 		ret = thread_cap;
@@ -302,6 +310,7 @@ int thread_create_main(struct process *process, u64 stack_base,
 	}
 
 	/* L1 icache & dcache have no coherence */
+	// 清空 L1 缓存
 	flush_idcache();
 
 	// return thread;

note.org

@@ -150,3 +150,7 @@ ELF Section、Segment 两个概念。
 **** 切换上下文
 
 返回上下文结构体的首地址就行
+
+*** 练习2
+
+process_create_root、thread_create_main 直接写在注释里面了。