搭建qemu环境

1.安装qemu

apt install qemu-system

2.编译内核

	设置gcc软链接sudo ln -s arm-linux-gnueabihf-gcc  arm-linux-gccsudo ln -s arm-linux-gnueabihf-ld  arm-linux-ldsudo ln -s arm-linux-gnueabihf-nm  arm-linux-nmsudo ln -s arm-linux-gnueabihf-objcopy  arm-linux-objcopysudo ln -s arm-linux-gnueabihf-ar  arm-linux-arsudo ln -s arm-linux-gnueabihf-strip  arm-linux-strip下载内核linux-5.6.14.tar.xz// 解压tar xvf linux-5.6.14.tar.xz// 编译默认配置make CROSS_COMPILE=arm-linux-gnueabi- ARCH=arm vexpress_defconfig// 编译安装，-j参数后面可以跟一个数字，表示并行任务的数量// make -j4表示同时运行四个编译任务。make CROSS_COMPILE=arm-linux-gnueabi- ARCH=arm -j8

3.编译文件系统

	下载文件系统busybox-1.37.0.tar.bz2 // 解压tar xvf busybox-1.37.0.tar.bz2 // 编译默认配置make defconfig// 编译make CROSS_COMPILE=arm-linux-gnueabi- -j8错误：1. ‘sha1_process_block64_shaNI’ undeclared 解决1. nano .config注释下面配置#define ENABLE_SHA1_HWACCEL解决2. nano libbb/hash_md5_sha.c添加条件判断修改前：/* Used also for sha256 */unsigned FAST_FUNC sha1_end(sha1_ctx_t *ctx, void *resbuf){unsigned hash_size;/* SHA stores total in BE, need to swap on LE arches: */common64_end(ctx, /*swap_needed:*/ BB_LITTLE_ENDIAN);hash_size = 8;if (ctx->process_block == sha1_process_block64#if ENABLE_SHA1_HWACCEL|| ctx->process_block == sha1_process_block64_shaNI#endif) {hash_size = 5;}/* This way we do not impose alignment constraints on resbuf: */if (BB_LITTLE_ENDIAN) {unsigned i;for (i = 0; i < hash_size; ++i)ctx->hash[i] = SWAP_BE32(ctx->hash[i]);}hash_size *= sizeof(ctx->hash[0]);memcpy(resbuf, ctx->hash, hash_size);return hash_size;}修改后：/* Used also for sha256 */unsigned FAST_FUNC sha1_end(sha1_ctx_t *ctx, void *resbuf){unsigned hash_size;/* SHA stores total in BE, need to swap on LE arches: */common64_end(ctx, /*swap_needed:*/ BB_LITTLE_ENDIAN);hash_size = 8;if (ctx->process_block == sha1_process_block64#if ENABLE_SHA1_HWACCEL/* 添加条件判断 */#if defined(__GNUC__) && (defined(__i386__) || defined(__x86__64__))|| ctx->process_block == sha1_process_block64_shaNI#endif#endif) {hash_size = 5;}/* This way we do not impose alignment constraints on resbuf: */if (BB_LITTLE_ENDIAN) {unsigned i;for (i = 0; i < hash_size; ++i)ctx->hash[i] = SWAP_BE32(ctx->hash[i]);}hash_size *= sizeof(ctx->hash[0]);memcpy(resbuf, ctx->hash, hash_size);return hash_size;}2. ‘IFLA_CAN_TERMINATION’ undeclared修改networking/libiproute/iplink.c添加条件判断修改前：case ARG_termination: {uint16_t val;NEXT_ARG();val = get_u16(*argv, keyword);addattr_l(&req.n, sizeof(req), IFLA_CAN_TERMINATION, &val, sizeof(val));break;}修改后：case ARG_termination: {uint16_t val;NEXT_ARG();val = get_u16(*argv, keyword);/* 添加条件判断 */#ifdef IFLA_CAN_TERMINATIONaddattr_l(&req.n, sizeof(req), IFLA_CAN_TERMINATION, &val, sizeof(val));#elsefprintf(stderr, "IFLA_CAN_TERMINATION is not supported on this system.\n");#endifbreak;}// 编译安装make install CROSS_COMPILE=arm-linux-gnueabi- -j8编译生成的bin文件在busybox-1.37.0/_install/目录下

4.制作根文件系统镜像
切换到busybox的上级目录，并使用如下脚本制作镜像

#!/bin/bashmkdir -p rootfs/{dev,etc/init.d,lib}
touch rootfs/etc/init.d/rcS
#这里用双引号可能会报错
echo -e '#!/bin/sh\n' > rootfs/etc/init.d/rcS
cp busybox-1.37.0/_install/* -r rootfs/
sudo cp -P /usr/arm-linux-gnueabihf/libc/lib/* rootfs/lib/ln -s bin/busybox rootfs/init sudo mknod rootfs/dev/tty1 c 4 1
sudo mknod rootfs/dev/tty2 c 4 2
sudo mknod rootfs/dev/tty3 c 4 3
sudo mknod rootfs/dev/tty4 c 4 4sudo chown root:root -R rootfs/*
sudo  chmod  777 rootfs/etc/init.d/rcSqemu-img create -f raw disk.img 512M
mkfs -t ext4 ./disk.img
mkdir  -p   tmpfs
sudo mount -o loop ./disk.img tmpfs/
sudo cp -r rootfs/* tmpfs/
sudo umount tmpfs
file disk.img

5.启动虚拟机开发板

sudo qemu-system-arm \-M vexpress-a9 \-m 512M \-kernel linux-5.6.14/arch/arm/boot/zImage \-dtb linux-5.6.14/arch/arm/boot/dts/vexpress-v2p-ca9.dtb \-nographic \-append "root=/dev/mmcblk0 rw console=ttyAMA0" \-sd disk.img运行成功，如下图
![在这里插入图片描述](https://i-blog.csdnimg.cn/direct/a11090ba506b47e78e1e2db350c3dcdf.png#pic_center)错误：EXT4-fs (mmcblk0): recovery complete
EXT4-fs (mmcblk0): mounted filesystem with ordered data mode. Opts: (null)
VFS: Mounted root (ext4 filesystem) on device 179:0.
Freeing unused kernel memory: 1024K
Run /sbin/init as init process
Run /etc/init as init process
Run /bin/init as init process
Run /bin/sh as init process
Kernel panic - not syncing: No working init found.  Try passing init= option to kernel. See Linux Documentation/admin-guide/init.rst for guidance.
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.6.14 #2
Hardware name: ARM-Versatile Express
[<80110804>] (unwind_backtrace) from [<8010c6a8>] (show_stack+0x10/0x14)
[<8010c6a8>] (show_stack) from [<807867b0>] (dump_stack+0xa0/0xb4)
[<807867b0>] (dump_stack) from [<80120f90>] (panic+0x118/0x320)
[<80120f90>] (panic) from [<807a0374>] (kernel_init+0x104/0x114)
[<807a0374>] (kernel_init) from [<801010e8>] (ret_from_fork+0x14/0x2c)
Exception stack(0x9e493fb0 to 0x9e493ff8)
3fa0:                                     00000000 00000000 00000000 00000000
3fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
3fe0: 00000000 00000000 00000000 00000000 00000013 00000000
---[ end Kernel panic - not syncing: No working init found.  Try passing init= option to kernel. See Linux Documentation/admin-guide/init.rst for guidance.1. <span style="color: red;">文件系统重init文件缺失</span>，检查我的文件系统中init文件正常。故排除2.busybox编译时未进行交叉编译导致文件为不是arm架构文件，file rootfs/bin/busybox命令查看并无问题。故排除参考博客：CentOS 7 利用qemu模拟ARM vexpress A9开发板3.交叉编译库未正常拷贝。检查rootfs/lib文件发现其下面没有交叉编译库的内容，而是一个软链接，指向一个不存在的路径。问题定位到了，修复如下：修改制作根文件系统镜像中sudo cp -P /usr/arm-linux-gnueabihf/lib/* rootfs/lib/为sudo cp /usr/arm-linux-gnueabihf/lib/sf/* rootfs/lib/，重新制作根文件系统镜像后正常了。可能不同版本ubuntu安装的 gcc-arm-linux-gnueabi 库路径不同，需要自己检查一下。

Kernel panic No working init found 可能原因：
1.文件系统重init文件缺失，检查我的文件系统中init文件正常。故排除

参考博客：buildroot编译内核启动报错：Kernel panic - not syncing: No working init found问题解决

2.busybox编译时未进行交叉编译导致文件为不是arm架构文件，file rootfs/bin/busybox命令查看并无问题，故排除

参考博客：CentOS 7 利用qemu模拟ARM vexpress A9开发板

3.交叉编译库未正常拷贝。，检查rootfs/lib文件发现其下面没有交叉编译库的内容，而是一个软链接，指向一个不存在的路径。问题定位到了，修复如下：

修改制作根文件系统镜像中sudo cp -P /usr/arm-linux-gnueabihf/lib/* rootfs/lib/为sudo cp /usr/arm-linux-gnueabihf/libc/lib/* rootfs/lib/，重新制作根文件系统镜像后正常了。

可能不同版本ubuntu安装的 gcc-arm-linux-gnueabi 库路径不同，需要自己检查一下。

参考博客：启动报错：Kernel panic - not syncing: No working init found. Try passing init= option to kernel.