finish exec3.1

lab3/CMakeLists.txt

@@ -2,7 +2,7 @@ cmake_minimum_required (VERSION 3.14)
 
 set(CMAKE_VERBOSE_MAKEFILE on)
 
-set(CMAKE_BUILD_TYPE "Release")  # "Release" or "Debug"
+set(CMAKE_BUILD_TYPE "Debug")  # "Release" or "Debug"
 set(CHCORE_PLAT "raspi3")
 set(CHCORE_ARCH "aarch64")
 

lab3/kernel/process/thread.c

@@ -153,7 +153,7 @@ static u64 load_binary(struct process *process,
 			 * prepare the arguments for the two following function calls: pmo_init
 			 * and vmspace_map_range.
 			 * pmo_init allocates the demanded size of physical memory for the PMO.
-			 * vmspace_map_range maps the pmo to a sepcific virtual memory address.
+			 * vmspace_map_range maps the pmo to a specific virtual memory address.
 			 * You should get the size of current segment and the virtual address
 			 * to be mapped from elf headers.
 			 * HINT: we suggest you use the seg_sz and p_vaddr variables for
@@ -161,6 +161,15 @@ static u64 load_binary(struct process *process,
 			 * page aligned segment size. Take care of the page alignment when allocating
 			 * and mapping physical memory.
 			 */
+            // 段实际数据大小
+            seg_sz = elf->p_headers[i].p_filesz;
+            // 段虚拟地址
+            p_vaddr = elf->p_headers[i].p_vaddr;
+            // 段映射结果大小，其实不太需要对齐，因为之后的逻辑已经处理了
+            seg_map_sz = ROUND_UP(elf->p_headers[i].p_memsz, PAGE_SIZE);
+            if (ROUND_DOWN(p_vaddr, PAGE_SIZE) + seg_map_sz < p_vaddr + elf->p_headers[i].p_memsz) {
+                seg_map_sz += PAGE_SIZE;
+            }
 
 			pmo = obj_alloc(TYPE_PMO, sizeof(*pmo));
 			if (!pmo) {
@@ -179,9 +188,19 @@ static u64 load_binary(struct process *process,
 			 * You should copy data from the elf into the physical memory in pmo.
 			 * The physical address of a pmo can be get from pmo->start.
 			 */
+            const char *section_data;
+            char *alloc_section;
+
+            // 复制段内存
+            section_data = bin + elf->p_headers[i].p_offset;
+            alloc_section = (char *) phys_to_virt(pmo->start);
+			kdebug("Copy segment[%d] from addr %lx -> %lx, len = %d\n", i, section_data, alloc_section, seg_sz);
+			memcpy(alloc_section, section_data, seg_sz);
 
 			flags = PFLAGS2VMRFLAGS(elf->p_headers[i].p_flags);
 
+            kdebug("Map segment[%d] from paddr %lx -> %lx, len = %d\n",
+                   i, pmo->start, ROUND_DOWN(p_vaddr, PAGE_SIZE), seg_map_sz);
 			ret = vmspace_map_range(vmspace,
 						ROUND_DOWN(p_vaddr, PAGE_SIZE),
 						seg_map_sz, flags, pmo);

lab3/kernel/sched/context.c

@@ -56,6 +56,12 @@ void init_thread_ctx(struct thread *thread, u64 stack, u64 func, u32 prio,
 	 */
 
 	/* Fill the context of the thread */
+	// 栈寄存器
+    thread->thread_ctx->ec.reg[SP_EL0] = stack;
+    // PC 计数器
+    thread->thread_ctx->ec.reg[ELR_EL1] = func;
+    // 状态字寄存器
+    thread->thread_ctx->ec.reg[SPSR_EL1] = SPSR_EL1_EL0t;
 
 	/* Set thread type */
 	thread->thread_ctx->type = type;

lab3/kernel/sched/sched.c

@@ -72,5 +72,5 @@ u64 switch_context(void)
 	 * Return the correct value in order to make eret_to_thread work correctly
 	 * in main.c
 	 */
-	return 0;
+	return (u64) &target_ctx->ec;
 }

note.org

@@ -121,3 +121,32 @@ boot/mmu.c:L109-110 映射了 KBASE+512M~KBASE+4G
 因此只需要类似操作，补全中间的 256M 即可。
 
 注意的是，寄存器保存的地址是 paddr_t
+
+** Lab 3
+
+*** Capability
+
+好像和 MC、Linux 的 Cap 都不太一样。这里的 Cap 是一个可变的描述符，用来指代一个内核资源。
+
+比起 Cap，更像是一个对象表。
+
+*** 练习1
+
+**** ELF 读入
+
+ELF Section、Segment 两个概念。
+
+- Section 是程序中的不同节，比如 .text。
+- Segment 是程序中实际分配的不同段，包括多个 Section，可以用 `readelf -l` 查看关系
+
+主要操作就是计算偏移与复制。
+
+其实连对齐都不用，直接就干上去也行，反正之前页表的时候已经处理了没对齐的情况。
+
+**** 初始化线程上下文
+
+照着文字写就行，初始化 TCB
+
+**** 切换上下文
+
+返回上下文结构体的首地址就行