Qemu模拟vexpress-a9: 启动uboot，tftp加载kernel，nfs加载根文件系统，图形界面启动

超、凢脫俗 2023-10-12 07:53 21阅读 0赞

### 文章目录 ###

*  Arm开发虚拟环境准备实验
 *   *  宿主操作系统
     *  Qemu
     *   *  Qemu网络设置
         *   *  网桥设置
             *  添加虚拟网卡
     *  交叉编译工具
     *  Uboot
     *  linux内核
     *  根文件系统
     *  TFTP服务
     *  NFS服务
     *  仿真开发板
     *  图形界面启动

# Arm开发虚拟环境准备实验 #

由于开发板携带不太方便，所以打算使用**Qemu**来模拟开发板进行嵌入式开发学习。

## 宿主操作系统 ##

为方便起见，采用 **Ubuntu 18.04.3 LTS (Bionic Beaver)** 作为宿主系统，采用默认配置进行虚拟机安装。虚拟机为4GB内存、8核心CPU、60GB硬盘。系统交换分区设置为8GB。

macrofun@QemuLab:~$ uname -a
    Linux QemuLab 5.0.0-29-generic #31~18.04.1-Ubuntu SMP Thu Sep 12 18:29:21 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

## Qemu ##

由于三星猎户座4412现在是用于自学的主流开发板，所以为了方便起见，使用Qemu来模拟ARM vexpress-a9电路板。 **vexpress**（Versatile Express Family）是ARM自己推出的开发板，主要是方便SOC厂商设计、验证和测试自己的SOC芯片。

> The Versatile Express development platform provides an ultra fast environment for prototyping the next generation of System-on-Chip designs, such as the Cortex-A9 Quad Core. Through a range of plug-in daughterboards hardware and software applications can be developed and debugged.

ARM架构和对应的Soc之间的关系如下表所示：

<table> 
 <tbody> 
  <tr> 
   <th>ARM架构</th> 
   <td>ARM7</td> 
   <td>ARM9</td> 
   <td>ARM11</td> 
   <td>Cotex-A8</td> 
   <td>Cotex-A9</td> 
  </tr> 
  <tr> 
   <th colspan="1">对应Soc</th> 
   <td>S3C44B0</td> 
   <td>S3C2440</td> 
   <td>S3C6410</td> 
   <td>S5PV210</td> 
   <td>Exynos4412</td> 
  </tr> 
 </tbody> 
</table>

1.  安装Qemu1工具

macrofun@QemuLab:~$ sudo apt-get install qemu qemu-system qemu-utils

1.  查看Qemu支持的ARM开发板的型号，可以看到它支持 vexpress-a9开发板

macrofun@QemuLab:~$ qemu-system-arm -M help

### Qemu网络设置 ###

虚拟网络一般有三种模式，即Host-Only、NAT、Bridge，目前应用最广泛的模式当属桥接模式。因为在该模式下，开发板相当于同网段内的一台独立的主机，使用很方便。

#### 网桥设置 ####

对于网桥的设置，主要有两种方式，即brctl和iproute2。需要注意的是，如果将一个设备接口加入到某一网桥当中，那么这个设备接口原有的IP地址信息将被丢弃。显然，此时连接到该设备接口上的网络会被中断一会儿。

1.  方法一：通过bridge-utils 软件包里面的 brctl 工具管理网桥。

# 新建一个网桥，名称为br0
    brctl addbr br0
    # 将网络设备（例如ens38）添加到网桥br0 
    brctl addif br0 ens38
    # 显示当前存在的网桥及其所连接的网络端口
    brctl show
    # 启动网桥
    ip link set up dev br0
    # 删除网桥，首先需要先关闭它
    ip link set dev br0 down
    brctl delbr br0

1.  方法二：通过iproute2软件包中的ip工具来管理网桥。

# 新建一个网桥，名称为br0
    ip link add name br0 type bridge
    # 启动网桥br0
    ip link set dev br0 up
    # 将一个网络端口ens38设置为混杂模式，并添加到网桥br0中
    ip link set dev ens38 promisc on
    # 将端口ens38添加到网桥中，并将其所有者设置为 br0
    ip link set dev ens38 master br0
    # 启动网络端口ens38
    ip link set dev ens38 up
    # 显示现存的网桥及其关联的端口，使用iproute2中的bridge工具
    bridge link show
    # 若要删除网桥，应首先移除它所关联的所有端口，同时关闭端口的混杂模式并关闭端口以将其恢复至原始状态
    ip link set ens38 promisc off
    ip link set ens38 down
    ip link set dev ens38 nomaster
    # 当网桥的配置清空后，删除该网桥br0
    ip link delete br0 type bridge

#### 添加虚拟网卡 ####

Linux添加虚拟网卡有三种方法：  
方法1: ifconfig命令创建\\删除虚拟网卡

macrofun@QemuLab:~$ ifconfig ens38:0 192.168.1.10 netmask 255.255.255.0 up

删除虚拟网卡:

macrofun@QemuLab:~$ ifconfig ens38:0 down

方法2: 修改网卡配置文件  
修改网卡的配置文件/etc/network/interfaces

> auto eth0 iface eth0 inet dhcp auto eth0:1  
> iface eth0:1 inet static  
> address 192.168.11.1  
> netmask 255.255.255.0  
> gateway 192.168.11.1 auto eth0:2 iface eth0:2 inet static  
> address 192.168.12.1  
> netmask 255.255.255.0  
> gateway 192.168.12.1

修改之后，使用如下命令重启网卡

macrofun@QemuLab:~$ sudo service networking restart

方法3：创建tap  
前两种方法都有一个特点，创建的网卡可有不同的ip地址，但是Mac地址相同，无法用来创建虚拟机。  
使用命令tunctl添加虚拟网卡tap。tun/tap 驱动程序实现了虚拟网卡的功能，tun表示虚拟的是点对点设备，tap表示虚拟的是以太网设备，这两种设备针对网络包实施不同的封装。  
首先安装uml-utilities软件包以获得tunctl工具

macrofun@QemuLab:~$ sudo apt-get install uml-utilities

添加虚拟网卡设备tap0

# TUNCTL(8) System Manager's Manual TUNCTL(8)
    # NAME
    # tunctl — create and manage persistent TUN/TAP interfaces
    # SYNOPSIS
    # tunctl [-f tun-clone-device] [-u owner] [-t device-name]
    # tunctl [-f tun-clone-device] -d device-name
    
    # 创建虚拟网卡设备，我的ubuntu的用户名是macrofun
    macrofun@QemuLab:~$ tunctl -t tap0 -u macrofun
    # 设置虚拟网卡
    macrofun@QemuLab:~$ ifconfig tap0 10.8.8.4 netmask 255.255.255.0 promisc up

根据上面的介绍，可以编写如下网桥管理脚本工具tuptap.sh：

#!/bin/bash
    if test -z $1 ; then
    	echo need a argument: down/up
    	exit
    fi 
     
    if [ "up" = $1 ] ; then
    	# 新建一个网桥，名称为br0
    	brctl addbr br0
    	# 将网络设备ens38添加到网桥br0 
    	ifconfig ens38 down
    	brctl addif br0 ens38
    	# 关闭生成树协议
    	brctl stp br0 off
     
    	ifconfig br0 10.8.8.3 netmask 255.255.255.0 promisc up
    	ifconfig ens38 10.8.8.2 netmask 255.255.255.0 promisc up
     	# 使用命令tunctl添加虚拟网卡tap
    	tunctl -t tap0 -u macrofun
    	ifconfig tap0 10.8.8.4 netmask 255.255.255.0 promisc up
    	brctl addif br0 tap0
    else
    	ifconfig tap0 down
    	brctl delif br0 tap0
    
    	ifconfig ens38 down
    	brctl delif br0 ens38
    
    	ifconfig br0 down
    	brctl delbr br0
    
    	ifconfig ens38 10.8.8.2 netmask 255.255.255.0
    fi

脚本编写完毕后，修改~/.bashrc，在尾部添加

> alias tuptapup=‘sudo ~/BIN/tuptap.sh up’  
> alias tuptapdown=‘sudo ~/BIN/tuptap.sh down’

同时，将tuptap.sh拷贝至/home/macrofun/BIN目录下。

## 交叉编译工具 ##

从网上找的arm-2014.05-29-arm-none-linux-gnueabi-i686-pc-linux-gnu.tar.bz2，解压至任意目录

macrofun@QemuLab:~/BIN/arm-2014.05$ ls
    arm-none-linux-gnueabi  bin  i686-pc-linux-gnu  lib  libexec  share

查看arm-none-linux-gnueabi-gcc的版本信息，结果报错

macrofun@QemuLab:~/BIN/arm-2014.05/bin$ ./arm-none-linux-gnueabi-gcc -v
    bash: ./arm-none-linux-gnueabi-gcc: No such file or directory

显然这是64位系统缺少32位兼容库造成的，安装32位运行库即可  
网上说是安装sudo apt-get install ia32-libs，但是新版本的ubuntu已不再支持这个软件包，安装时会有错误提示。新版本已经使用lib32ncurses5 lib32z1这两个软件包进行了替代。  
故执行如下命令即可。

macrofun@QemuLab:~$ sudo apt-get install lib32ncurses5 lib32z1

之后，在环境变量PATH中添加该路径/home/macrofun/BIN/arm-2014.05/bin即可

> PATH=$PATH:/home/macrofun/BIN/arm-2014.05/bin

之后即可查看该交叉编译工具的版本信息

macrofun@QemuLab:~$ arm-none-linux-gnueabi-gcc -v
    Using built-in specs.
    COLLECT_GCC=arm-none-linux-gnueabi-gcc
    COLLECT_LTO_WRAPPER=/home/macrofun/BIN/arm-2014.05/bin/../libexec/gcc/arm-none-linux-gnueabi/4.8.3/lto-wrapper
    Target: arm-none-linux-gnueabi
    Configured with: /scratch/maciej/arm-linux-2014.05-rel/src/gcc-4.8-2014.05/configure 
    --build=i686-pc-linux-gnu 
    --host=i686-pc-linux-gnu --target=arm-none-linux-gnueabi --enable-threads 
    --disable-libmudflap --disable-libssp --disable-libstdcxx-pch 
    --enable-extra-sgxxlite-multilibs --with-arch=armv5te --with-gnu-as 
    --with-gnu-ld --with-specs='%{save-temps: -fverbose-asm} %{funwind-tables|fno-unwind-tables|mabi=*|ffreestanding|nostdlib:;:-funwind-tables} -D__CS_SOURCERYGXX_MAJ__=2014 -D__CS_SOURCERYGXX_MIN__=5 -D__CS_SOURCERYGXX_REV__=29' 
    --enable-languages=c,c++ --enable-shared --enable-lto --enable-symvers=gnu 
    --enable-__cxa_atexit --with-pkgversion='Sourcery CodeBench Lite 2014.05-29' --with-bugurl=https://sourcery.mentor.com/GNUToolchain/ --disable-nls 
    --prefix=/opt/codesourcery --with-sysroot=/opt/codesourcery/arm-none-linux-gnueabi/libc 
    --with-build-sysroot=/scratch/maciej/arm-linux-2014.05-rel/install/opt/codesourcery/arm-none-linux-gnueabi/libc 
    --with-gmp=/scratch/maciej/arm-linux-2014.05-rel/obj/pkg-2014.05-29-arm-none-linux-gnueabi/arm-2014.05-29-arm-none-linux-gnueabi.extras/host-libs-i686-pc-linux-gnu/usr 
    --with-mpfr=/scratch/maciej/arm-linux-2014.05-rel/obj/pkg-2014.05-29-arm-none-linux-gnueabi/arm-2014.05-29-arm-none-linux-gnueabi.extras/host-libs-i686-pc-linux-gnu/usr 
    --with-mpc=/scratch/maciej/arm-linux-2014.05-rel/obj/pkg-2014.05-29-arm-none-linux-gnueabi/arm-2014.05-29-arm-none-linux-gnueabi.extras/host-libs-i686-pc-linux-gnu/usr 
    --with-isl=/scratch/maciej/arm-linux-2014.05-rel/obj/pkg-2014.05-29-arm-none-linux-gnueabi/arm-2014.05-29-arm-none-linux-gnueabi.extras/host-libs-i686-pc-linux-gnu/usr 
    --with-cloog=/scratch/maciej/arm-linux-2014.05-rel/obj/pkg-2014.05-29-arm-none-linux-gnueabi/arm-2014.05-29-arm-none-linux-gnueabi.extras/host-libs-i686-pc-linux-gnu/usr 
    --disable-libgomp --disable-libitm --enable-libatomic --disable-libssp 
    --enable-poison-system-directories 
    --with-build-time-tools=/scratch/maciej/arm-linux-2014.05-rel/install/opt/codesourcery/arm-none-linux-gnueabi/bin 
    --with-build-time-tools=/scratch/maciej/arm-linux-2014.05-rel/install/opt/codesourcery/arm-none-linux-gnueabi/bin SED=sed
    Thread model: posix
    gcc version 4.8.3 20140320 (prerelease) (Sourcery CodeBench Lite 2014.05-29)

## Uboot ##

1.  从Uboot官网FTP服务器上ftp://ftp.denx.de/pub/u-boot/下载较新的源码文件u-boot-2018.11.tar.bz2
2.  解压至当前目录

macrofun@QemuLab:~$ tar -xjvf u-boot-2018.11.tar.bz2  -C .

1.  解压后进入Uboot目录，内容如下：

macrofun@QemuLab:~/Qemu/u-boot-2018.11$ ls
    api        configs        env       lib          README
    arch       disk           examples  Licenses     runVexpress-a9.sh
    board      doc            fs        MAINTAINERS  scripts
    cmd        Documentation  include   Makefile     test
    common     drivers        Kbuild    net          tools
    config.mk  dts            Kconfig   post

1.  查看vexpress开发板默认配置文件

macrofun@QemuLab:~/Qemu/u-boot-2018.11$ ls configs/vex*
    configs/vexpress_aemv8a_dram_defconfig
    configs/vexpress_aemv8a_juno_defconfig
    configs/vexpress_aemv8a_semi_defconfig
    configs/vexpress_ca15_tc2_defconfig
    configs/vexpress_ca5x2_defconfig
    configs/vexpress_ca9x4_defconfig

1.  可以看到，Uboot默认就支持vexpress-a9开发板，所以直接修改Makefile，配置交叉编译工具即可。  
    在Makefile里面增加两行：

> ARCH ?= arm  
> CROSS\_COMPILE ?= arm-none-linux-gnueabi-

注意，arm-none-linux-gnueabi-后面不要有空格。

之后执行make命令即可。

macrofun@QemuLab:~/Qemu/u-boot-2018.11$ make vexpress_ca9x4_defconfig
      HOSTCC  scripts/basic/fixdep
      HOSTCC  scripts/kconfig/conf.o
      YACC    scripts/kconfig/zconf.tab.c
      LEX     scripts/kconfig/zconf.lex.c
      HOSTCC  scripts/kconfig/zconf.tab.o
      HOSTLD  scripts/kconfig/conf
    #
    # configuration written to .config
    #
    macrofun@QemuLab:~/Qemu/u-boot-2018.11$ make

执行时报错  
/bin/sh: 1: cc: not found  
/bin/sh: 1: bison: not found  
/bin/sh: 1: flex: not found  
原因是缺少相应的软件包，安装即可

macrofun@QemuLab:~$ sudo apt-get install build-essential bison flex

安装完毕后，再次执行make命令，报错

之后，通过menuconfig来设置bootargs和bootcmd

bootcmd: tftp 0x60003000 uImage;tftp 0x60500000 vexpress-v2p-ca9.dtb; bootm 0x60003000 - 0x60500000;
    
    bootargs: root=/dev/nfs rw nfsroot=10.8.8.3:/home/macrofun/NFS_HOME,proto=tcp,nfsvers=4,nolock init=/linuxrc ip=10.8.8.100 console=ttyAMA0

macrofun@QemuLab:~/Qemu/u-boot-2018.11$ make -j8
    scripts/kconfig/conf  --syncconfig Kconfig
      CHK     include/config.h
      CFG     u-boot.cfg
      GEN     include/autoconf.mk.dep
      GEN     include/autoconf.mk
    *** Your GCC is older than 6.0 and is not supported
    arch/arm/config.mk:66: recipe for target 'checkgcc6' failed
    make: *** [checkgcc6] Error 1

解决这个错误有两个思路：  
其一是升级自己的交叉编译器版本[https://www.linaro.org/downloads/][https_www.linaro.org_downloads]，使其高于6.0；  
**Latest Linux Targeted Binary Toolchain Releases**

<table> 
 <tbody> 
  <tr> 
   <th>arm-linux-gnueabihf</th> 
   <td align="left">32-bit Armv7 Cortex-A, hard-float, little-endian</td> 
  </tr> 
  <tr> 
   <th colspan="1">armv8l-linux-gnueabihf</th> 
   <td align="left">32-bit Armv8 Cortex-A, hard-float, little-endian</td> 
  </tr> 
  <tr> 
   <th colspan="1">aarch64-linux-gnu</th> 
   <td align="left">64-bit Armv8 Cortex-A, little-endian</td> 
  </tr> 
 </tbody> 
</table>

**Latest Bare-Metal Targeted Binary Toolchain Releases**

<table> 
 <tbody> 
  <tr> 
   <th>arm-eabi</th> 
   <td align="left">32-bit Armv7 Cortex-A, hard-float, little-endian</td> 
  </tr> 
  <tr> 
   <th colspan="1">aarch64-elf</th> 
   <td align="left">32-bit Armv8 Cortex-A, hard-float, little-endian</td> 
  </tr> 
 </tbody> 
</table>

其二就是修改config.mk文件，注释掉编译器版本检查。 这里我们采取第二种方法。

macrofun@QemuLab:~/Qemu/u-boot-2018.11$ vim arch/arm/config.mk +66

49 # Only test once
     50 ifeq ($(CONFIG_$(SPL_)SYS_THUMB_BUILD),y)
     51 #archprepare: checkthumb checkgcc6
     52 archprepare: checkthumb
     53 
     54 checkthumb:
     55         @if test "$(call cc-name)" = "gcc" -a \
     56                         "$(call cc-version)" -lt "0404"; then \
     57                 echo -n '*** Your GCC does not produce working '; \
     58                 echo 'binaries in THUMB mode.'; \
     59                 echo '*** Your board is configured for THUMB mode.'    ; \
     60                 false; \
     61         fi
     62 else
     63 #archprepare: checkgcc6
     64 archprepare: 
     65 endif
     66 
     67 #checkgcc6:
     68 #       @if test "$(call cc-name)" = "gcc" -a \
     69 #                       "$(call cc-version)" -lt "0600"; then \
     70 #               echo '*** Your GCC is older than 6.0 and is not sup    ported'; \
     71 #               false; \
     72 #       fi
     73

## linux内核 ##

从官方网站https://mirrors.edge.kernel.org/pub/linux/kernel/下载linux内核，这里选择的是linux-4.0.9.tar.gz  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0Jha2VyVGhlR3JlYXQ_size_16_color_FFFFFF_t_70]  
同样，在顶层Makefile文件中添加如下两行代码

> ARCH ?= arm  
> CROSS\_COMPILE ?= arm-none-linux-gnueabi-

同样注意，arm-none-linux-gnueabi-后面不要有空格。  
之后，到 arch/arm/configs/ 目录查看所有自带的配置文件。

macrofun@QemuLab:~/Qemu/linux-4.0.9$ ls arch/arm/configs/vex*
    arch/arm/configs/vexpress_defconfig

使用内核的默认配置进行编译

macrofun@QemuLab:~/Qemu/linux-4.0.9$ make vexpress_defconfig
      HOSTCC  scripts/basic/fixdep
      HOSTCC  scripts/basic/bin2c
      HOSTCC  scripts/kconfig/conf.o
      HOSTCC  scripts/kconfig/zconf.tab.o
      HOSTLD  scripts/kconfig/conf
    #
    # configuration written to .config
    #

因为**ubuntu18.04使用的是NFS version 4**，所以需要通过menuconfig配置内核，使其支持nfs v4版本，同时支持nfs根文件系统。

File systems  --->  Network File Systems 
    <*>   NFS client support         
    <*>     NFS client support for NFS version 2        
    <*>     NFS client support for NFS version 3       
    [*]       NFS client support for the NFSv3 ACL protocol extension
    <*>     NFS client support for NFS version 4     
    [*]     Provide swap over NFS support      
    [*]   NFS client support for NFSv4.1     
    [*]     NFS client support for NFSv4.2      
    (kernel.org) NFSv4.1 Implementation ID Domain       
    [*]     NFSv4.1 client support for migration       
    [*]   Root file system on NFS

配置完毕后，开始生成用于u-boot引导的uImage

macrofun@QemuLab:~/Qemu/linux-4.0.9$ make uImage -j8

编译报错

AS      arch/arm/boot/compressed/piggy.gzip.o
      LD      arch/arm/boot/compressed/vmlinux
      OBJCOPY arch/arm/boot/zImage
      Kernel: arch/arm/boot/zImage is ready
    multiple (or no) load addresses: 
    This is incompatible with uImages
    Specify LOADADDR on the commandline to build an uImage
    arch/arm/boot/Makefile:79: recipe for target 'arch/arm/boot/uImage' failed
    make[1]: *** [arch/arm/boot/uImage] Error 1
    arch/arm/Makefile:308: recipe for target 'uImage' failed
    make: *** [uImage] Error 2

这里需要指定内核的加载地址LOADADDR，参考ARM® CoreTile Express A9×4Cortex®  
\-A9 MPCore (V2P-CA9)Technical Reference Manual.pdf（http://infocenter.arm.com/help/topic/com.arm.doc.dui0448i/DUI0448I\_v2p\_ca9\_trm.pdf），选择LOADADDR=0x60003000，重新执行内核编译命令。

macrofun@QemuLab:~/Qemu/linux-4.0.9$ make clean
      CLEAN   .
      CLEAN   arch/arm/kernel
      CLEAN   drivers/tty/vt
      CLEAN   drivers/video/logo
      CLEAN   kernel/time
      CLEAN   kernel
      CLEAN   lib
      CLEAN   usr
      CLEAN   arch/arm/boot/compressed
      CLEAN   arch/arm/boot
      CLEAN   .tmp_versions
    macrofun@QemuLab:~/Qemu/linux-4.0.9$ make vexpress_defconfig
      HOSTCC  scripts/basic/fixdep
      HOSTCC  scripts/basic/bin2c
      HOSTCC  scripts/kconfig/conf.o
      HOSTCC  scripts/kconfig/zconf.tab.o
      HOSTLD  scripts/kconfig/conf
    #
    # configuration written to .config
    #
    macrofun@QemuLab:~/Qemu/linux-4.0.9$ make LOADADDR=0x60003000 uImage -j8

再次有新的错误产生。

AS      arch/arm/boot/compressed/piggy.gzip.o
      LD      arch/arm/boot/compressed/vmlinux
      OBJCOPY arch/arm/boot/zImage
      Kernel: arch/arm/boot/zImage is ready
      UIMAGE  arch/arm/boot/uImage
    "mkimage" command not found - U-Boot images will not be built
    arch/arm/boot/Makefile:79: recipe for target 'arch/arm/boot/uImage' failed
    make[1]: *** [arch/arm/boot/uImage] Error 1
    arch/arm/Makefile:308: recipe for target 'uImage' failed
    make: *** [uImage] Error 2

这是ubuntu缺少mkimage工具，无法生成uImage，该工具在编译uboot的时候，在tools目录下已经生成，将其拷贝到自己的BIN目录即可。

macrofun@QemuLab:~/Qemu/linux-4.0.9$ cp ../u-boot-2018.11/tools/mkimage ~/BIN
    macrofun@QemuLab:~/Qemu/linux-4.0.9$ make LOADADDR=0x60003000 uImage -j8
      CHK     include/config/kernel.release
      CHK     include/generated/uapi/linux/version.h
      CHK     include/generated/utsrelease.h
    make[1]: 'include/generated/mach-types.h' is up to date.
      CALL    scripts/checksyscalls.sh
      CHK     include/generated/compile.h
      CHK     kernel/config_data.h
      Kernel: arch/arm/boot/Image is ready
      Kernel: arch/arm/boot/zImage is ready
      UIMAGE  arch/arm/boot/uImage
    Image Name:   Linux-4.0.9
    Created:      Tue Sep 24 14:39:48 2019
    Image Type:   ARM Linux Kernel Image (uncompressed)
    Data Size:    3422648 Bytes = 3342.43 KiB = 3.26 MiB
    Load Address: 60003000
    Entry Point:  60003000
      Image arch/arm/boot/uImage is ready

编译生成设备树文件

macrofun@QemuLab:~/Qemu/linux-4.0.9$ make dtbs
      CHK     include/config/kernel.release
      CHK     include/generated/uapi/linux/version.h
      CHK     include/generated/utsrelease.h
    make[1]: 'include/generated/mach-types.h' is up to date.
      CALL    scripts/checksyscalls.sh
      DTC     arch/arm/boot/dts/vexpress-v2p-ca5s.dtb
      DTC     arch/arm/boot/dts/vexpress-v2p-ca9.dtb
      DTC     arch/arm/boot/dts/vexpress-v2p-ca15-tc1.dtb
      DTC     arch/arm/boot/dts/vexpress-v2p-ca15_a7.dtb

## 根文件系统 ##

使用busybox来制作根文件系统。首先到https://busybox.net/downloads/下载较新的Busybox源码进行编译。这里选择的是busybox-1.30.1.tar.bz2。  
同样，在顶层Makefile文件中添加如下两行代码

> ARCH ?= arm  
> CROSS\_COMPILE ?= arm-none-linux-gnueabi-

同样注意，arm-none-linux-gnueabi-后面不要有空格。  
直接make menuconfig  
勾选Settings —> \[\*\]Build static binary (no shared libs)  
设置Cross compiler prefix为arm-none-linux-gnueabi-

make -j8  
make install  
之后，在busybox主目录的\_install下面，就生成了busybox根文件系统。  
之后，在该目录下补全标准的linux目录结构。

macrofun@QemuLab:~/Qemu/busybox-1.30.1$ cd _install/
    macrofun@QemuLab:~/Qemu/busybox-1.30.1/_install$ ls
    bin  linuxrc  sbin  usr
    macrofun@QemuLab:~/Qemu/busybox-1.30.1/_install$ mkdir dev etc lib proc sys tmp etc/init.d
    macrofun@QemuLab:~/Qemu/busybox-1.30.1/_install$ ls
    bin  dev  etc  lib  linuxrc  proc  sbin  sys  tmp  usr

最后，把交叉编译工具自带的库拷贝过来。  
同时，在根文件系统的etc目录下添加四个配置文件 fstab inittab profile init.d/rcS

macrofun@QemuLab:~/Qemu/busybox-1.30.1/_install/etc$ tree
    .
    ├── fstab
    ├── init.d
    │   └── rcS
    ├── inittab
    └── profile
    
    1 directory, 4 files

profile文件

#!/bin/sh 
    export HOSTNAME=MacrofunArm
    export USER=root
    export HOME=root
    export PS1="[$USER@$HOSTNAME \W]\# "
    PATH=/bin:/sbin:/usr/bin:/usr/sbin 
    LD_LIBRARY_PATH=/lib:/usr/lib:$LD_LIBRARY_PATH
    export PATH LD_LIBRARY_PATH

inittab文件

::sysinit:/etc/init.d/rcS 
    ::askfirst:-/bin/sh
    ::restart:/sbin/init 
    ::ctrlaltdel:/sbin/reboot

fstab文件

#device mount-point type options dump fsck orde
    proc   /proc  proc  defaults  0  0
    tmpfs  /tmp   tmpfs defaults  0  0
    sysfs  /sys   sysfs defaults  0  0
    tmpfs  /dev   tmpfs defaults  0  0

etc/rcS文件

#!/bin/sh 
    /bin/mount -a
    echo /sbin/mdev > /proc/sys/kernel/hotplug 
    /sbin/mdev -s

## TFTP服务 ##

1.  安装tftp服务器和客户端

macrofun@QemuLab:~$ sudo apt-get install tftp-hpa tftpd-hpa

1.  修改tftp配置文件

macrofun@QemuLab:~$ cat /etc/default/tftpd-hpa 
    # /etc/default/tftpd-hpa
    
    TFTP_USERNAME="tftp"
    TFTP_DIRECTORY="/home/macrofun/TFTP_HOME"
    TFTP_ADDRESS=":69"
    TFTP_OPTIONS="--secure"

1.  重启tftp服务

macrofun@QemuLab:~$ sudo service tftpd-hpa restart

1.  测试tftp服务是否正常

macrofun@QemuLab:~$ ls
    BIN      Documents  examples.desktop  Pictures  Qemu       TFTP_HOME
    Desktop  Downloads  Music             Public    Templates  Videos
    
    macrofun@QemuLab:~$ ls /home/macrofun/TFTP_HOME/
    Image  uImage  vexpress-v2p-ca9.dtb  zImage
    
    macrofun@QemuLab:~$ tftp localhost
    tftp> get uImage
    tftp> quit
    
    macrofun@QemuLab:~$ ls
    BIN      Documents  examples.desktop  Pictures  Qemu       TFTP_HOME  Videos
    Desktop  Downloads  Music             Public    Templates  uImage

可以发现，uImage可以通过tftp服务正常下载。

## NFS服务 ##

1.  安装 NFS服务器和客户端

macrofun@QemuLab:~$ sudo apt-get install nfs-kernel-server nfs-common

1.  修改nfs配置文件

macrofun@QemuLab:~$ cat /etc/exports 
    # /etc/exports: the access control list for filesystems which may be exported
    # to NFS clients. See exports(5).
    #
    # Example for NFSv2 and NFSv3:
    # /srv/homes hostname1(rw,sync,no_subtree_check) hostname2(ro,sync,no_subtree_check)
    #
    # Example for NFSv4:
    # /srv/nfs4 gss/krb5i(rw,sync,fsid=0,crossmnt,no_subtree_check)
    # /srv/nfs4/homes gss/krb5i(rw,sync,no_subtree_check)
    #
    /home/macrofun/NFS_HOME *(rw,sync,no_root_squash,no_subtree_check)

1.  创建NFS\_HOME目录并将根文件系统全部拷贝至此目录下

macrofun@QemuLab:~$ mkdir NFS_HOME
    macrofun@QemuLab:~$ cp Qemu/busybox-1.30.1/_install/* -ra NFS_HOME/

1.  重启nfs服务

macrofun@QemuLab:~$ sudo service nfs-kernel-server restart

1.  测试nfs服务是否正常

macrofun@QemuLab:~$ ls NFS_HOME/
    bin  dev  etc  lib  linuxrc  proc  sbin  sys  tmp  usr
    macrofun@QemuLab:~$ ls /opt
    macrofun@QemuLab:~$ sudo mount -t nfs -o nolock 192.168.3.100:/home/macrofun/NFS_HOME /opt
    macrofun@QemuLab:~$ ls /opt
    bin  dev  etc  lib  linuxrc  proc  sbin  sys  tmp  usr
    macrofun@QemuLab:~$ sudo umount /opt

## 仿真开发板 ##

1.  将前几步生成的镜像文件拷贝至TFTP目录

macrofun@QemuLab:~/Qemu/linux-4.0.9$ rm ~/TFTP_HOME/*
    macrofun@QemuLab:~/Qemu/linux-4.0.9$ ls /home/macrofun/TFTP_HOME/
    macrofun@QemuLab:~/Qemu/linux-4.0.9$ cp -f arch/arm/boot/uImage  ~/TFTP_HOME/
    macrofun@QemuLab:~/Qemu/linux-4.0.9$ cp -f arch/arm/boot/zImage  ~/TFTP_HOME/
    macrofun@QemuLab:~/Qemu/linux-4.0.9$ cp -f arch/arm/boot/dts/vexpress-v2p-ca9.dtb  ~/TFTP_HOME/
    macrofun@QemuLab:~/Qemu/linux-4.0.9$ ls /home/macrofun/TFTP_HOME/
    uImage  vexpress-v2p-ca9.dtb  zImage

1.  使用qemu启动u-boot

macrofun@QemuLab:~/Qemu/u-boot-2018.11$ tuptapup 
    Set 'tap0' persistent and owned by uid 1000
    macrofun@QemuLab:~/Qemu/u-boot-2018.11$ qemu-system-arm -M vexpress-a9 -m 512 -nographic  -net nic -net tap,ifname=tap0,script=no -kernel u-boot

查看主机虚拟网卡：

启动界面如下所示：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0Jha2VyVGhlR3JlYXQ_size_16_color_FFFFFF_t_70 1]

1.  设置u-boot的IP、网关和子网掩码，内核启动参数bootargs

=> setenv ipaddr 10.8.8.100; setenv netmask 255.255.255.0; setenv serverip 10.8.8.3;
    => setenv bootargs 'root=/dev/nfs rw nfsroot=10.8.8.3:/home/macrofun/NFS_HOME init=/linuxrc ip=10.8.8.100 console=ttyAMA0';
    => saveenv
    
    Saving Environment to Flash... . done
    Un-Protected 1 sectors
    Erasing Flash...
    . done
    Erased 1 sectors
    Writing to Flash... done
    . done
    Protected 1 sectors
    OK
    =>

1.  测试uboot和ubuntu主机网络是否连通

=> ping 10.8.8.3
    
    smc911x: MAC 52:54:00:12:34:56
    smc911x: detected LAN9118 controller
    smc911x: phy initialized
    smc911x: MAC 52:54:00:12:34:56
    Using smc911x-0 device
    smc911x: MAC 52:54:00:12:34:56
    host 10.8.8.3 is alive

1.  加载内核镜像和设备树文件

=> tftp 0x60003000 uImage;
    
    smc911x: MAC 52:54:00:12:34:56
    smc911x: detected LAN9118 controller
    smc911x: phy initialized
    smc911x: MAC 52:54:00:12:34:56
    Using smc911x-0 device
    TFTP from server 10.8.8.3; our IP address is 10.8.8.100
    Filename 'uImage'.
    Load address: 0x60003000
    Loading: #################################################################
    	 #################################################################
    	 #################################################################
    	 #######################################
    	 5.7 MiB/s
    done
    Bytes transferred = 3422712 (3439f8 hex)
    smc911x: MAC 52:54:00:12:34:56
    
    
    => tftp 0x60500000 vexpress-v2p-ca9.dtb;
    
    smc911x: MAC 52:54:00:12:34:56
    smc911x: detected LAN9118 controller
    smc911x: phy initialized
    smc911x: MAC 52:54:00:12:34:56
    Using smc911x-0 device
    TFTP from server 10.8.8.3; our IP address is 10.8.8.100
    Filename 'vexpress-v2p-ca9.dtb'.
    Load address: 0x60500000
    Loading: #
    	 3.3 MiB/s
    done
    Bytes transferred = 14048 (36e0 hex)
    smc911x: MAC 52:54:00:12:34:56
    
    
    => bootm 0x60003000 - 0x60500000;

等待linux内核启动完毕之后，效果如下所示：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0Jha2VyVGhlR3JlYXQ_size_16_color_FFFFFF_t_70 2]

## 图形界面启动 ##

命令很简单，在启动u-boot的时候，就通过图形界面启动，启动命令如下：

macrofun@QemuLab:~/Qemu/u-boot-2018.11$ tuptapup 
    Set 'tap0' persistent and owned by uid 1000
    macrofun@QemuLab:~/Qemu/u-boot-2018.11$ qemu-system-arm -M vexpress-a9 -m 512 -serial stdio  -net nic -net tap,ifname=tap0,script=no -kernel u-boot

uboot启动后界面如下所示：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0Jha2VyVGhlR3JlYXQ_size_16_color_FFFFFF_t_70 3]  
在u-boot命令行中修改启动参数bootargs如下

=> setenv bootargs root=/dev/nfs rw nfsroot=10.8.8.3:/home/macrofun/NFS_HOME,proto=tcp,nfsvers=4,nolock init=/linuxrc ip=10.8.8.100 console=ttyAMA0 console=tty0
    -> saveenv
    => run bootcmd

启动后界面如下所示：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0Jha2VyVGhlR3JlYXQ_size_16_color_FFFFFF_t_70 4]

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0Jha2VyVGhlR3JlYXQ_size_16_color_FFFFFF_t_70 5]

--------------------

1.  [Qemu官网][Qemu] ↩︎

[https_www.linaro.org_downloads]: https://www.linaro.org/downloads/
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0Jha2VyVGhlR3JlYXQ_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20190924141020847.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0Jha2VyVGhlR3JlYXQ=,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0Jha2VyVGhlR3JlYXQ_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20190924161730728.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0Jha2VyVGhlR3JlYXQ=,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0Jha2VyVGhlR3JlYXQ_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/20190924172255140.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0Jha2VyVGhlR3JlYXQ=,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0Jha2VyVGhlR3JlYXQ_size_16_color_FFFFFF_t_70 3]: https://img-blog.csdnimg.cn/20190925103155202.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0Jha2VyVGhlR3JlYXQ=,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0Jha2VyVGhlR3JlYXQ_size_16_color_FFFFFF_t_70 4]: https://img-blog.csdnimg.cn/2019092510414084.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0Jha2VyVGhlR3JlYXQ=,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0Jha2VyVGhlR3JlYXQ_size_16_color_FFFFFF_t_70 5]: https://img-blog.csdnimg.cn/20190925104200936.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0Jha2VyVGhlR3JlYXQ=,size_16,color_FFFFFF,t_70
[Qemu]: https://www.qemu.org/