From 5abf7691e664b0502ba030bb5063620a478adcc7 Mon Sep 17 00:00:00 2001
From: equation314 <equation618@gmail.com>
Date: Thu, 27 Dec 2018 18:36:27 +0800
Subject: [PATCH] aarch64/doc: update boot.md & table of contents

---
 docs/2_OSLab/g2/boot.md        | 15 +++++++++++++--
 docs/2_OSLab/g2/drivers.md     | 12 +++++++++++-
 docs/2_OSLab/g2/interrupt.md   |  1 +
 docs/2_OSLab/g2/peripherals.md |  1 -
 docs/2_OSLab/g2/raspi3.md      |  4 ++--
 5 files changed, 27 insertions(+), 6 deletions(-)
 create mode 100644 docs/2_OSLab/g2/interrupt.md
 delete mode 100644 docs/2_OSLab/g2/peripherals.md

diff --git a/docs/2_OSLab/g2/boot.md b/docs/2_OSLab/g2/boot.md
index f838739..d17118c 100644
--- a/docs/2_OSLab/g2/boot.md
+++ b/docs/2_OSLab/g2/boot.md
@@ -48,7 +48,18 @@ SECTIONS {
 
 ## boot.S
 
-CPU 启动代码位于 `kernel/src/arch/aarch64/boot/boot.S`，主要流程如下：
+CPU 启动代码位于 `kernel/src/arch/aarch64/boot/boot.S`，负责初始化一些系统寄存器，并将当前异常级别(exception level)切换到 EL1。
+
+AArch64 有 4 个异常级别，相当于 x86 的特权级，分别为：
+
+* EL0: Applications.
+* EL1: OS kernel and associated functions that are typically described as privileged.
+* EL2: Hypervisor.
+* EL3: Secure monitor.
+
+在 RustOS 中，内核将运行在 EL1 上，用户程序将运行在 EL0 上。
+
+`boot.S` 的主要流程如下：
 
 1. 获取核的编号，目前只使用 0 号核，其余核将被闲置：
 
@@ -66,7 +77,7 @@ CPU 启动代码位于 `kernel/src/arch/aarch64/boot/boot.S`，主要流程如
         b       halt
     ```
 
-2. 读取当前异常级别(Exception level)：
+2. 读取当前异常级别：
 
     ```armasm
     # read the current exception level into x0 (ref: C5.2.1)
diff --git a/docs/2_OSLab/g2/drivers.md b/docs/2_OSLab/g2/drivers.md
index dd94d13..2d415c9 100644
--- a/docs/2_OSLab/g2/drivers.md
+++ b/docs/2_OSLab/g2/drivers.md
@@ -1 +1,11 @@
-# 驱动
+# 设备驱动
+
+## Mini UART
+
+## Timer
+
+## Mailbox
+
+## Framebuffer
+
+## Console
diff --git a/docs/2_OSLab/g2/interrupt.md b/docs/2_OSLab/g2/interrupt.md
new file mode 100644
index 0000000..4f57665
--- /dev/null
+++ b/docs/2_OSLab/g2/interrupt.md
@@ -0,0 +1 @@
+# 中断
diff --git a/docs/2_OSLab/g2/peripherals.md b/docs/2_OSLab/g2/peripherals.md
deleted file mode 100644
index 83ddc31..0000000
--- a/docs/2_OSLab/g2/peripherals.md
+++ /dev/null
@@ -1 +0,0 @@
-# 外围设备
diff --git a/docs/2_OSLab/g2/raspi3.md b/docs/2_OSLab/g2/raspi3.md
index c9fb8ee..268ec5f 100644
--- a/docs/2_OSLab/g2/raspi3.md
+++ b/docs/2_OSLab/g2/raspi3.md
@@ -11,7 +11,7 @@
 * [概述](overview.md)
 * [环境配置](environment.md)
 * [启动](boot.md)
-* [外围设备](peripherals.md)
+* [中断](interrupt.md)
 * [内存管理](memory.md)
 * [上下文切换](context.md)
-* [驱动](drivers.md)
+* [设备驱动](drivers.md)