qemu以64位和32位的方式跑busybox

两种方式x86_64 和32位的i386方式


-----------x86_64-----------------------------------------
参考http://mgalgs.github.io/2015/05/16/how-to-build-a-custom-linux-kernel-for-qemu-2015-edition.html

下载busybox和linux内核

TOP=/var/www/mytest
wget http://distro.ibiblio.org/tinycorelinux/6.x/armv6/release/src/busybox/busybox-1.23.2.tar.bz2
wget https://www.kernel.org/pub/linux/kernel/v4.x/linux-4.0.3.tar.xz

cd $TOP/busybox-1.23.2

#这步骤很重要，busybox不生成动态库
mkdir -pv ../obj/busybox-x86
make O=../obj/busybox-x86 defconfig

make O=../obj/busybox-x86 menuconfig
-> Busybox Settings
  -> Build Options
[ ] Build BusyBox as a static binary (no shared libs)

Go to that location, select it, save, and exit.

$ cd ../obj/busybox-x86
$ make -j2
$ make install

把busybox编译好的文件生成 initramfs

$ 
mkdir -p $TOP/initramfs/x86-busybox
$ cd $TOP/initramfs/x86-busybox
$ mkdir -pv {bin,sbin,etc,proc,sys,usr/{bin,sbin}}
$ cp -av $TOP/obj/busybox-x86/_install/* .

需要一个启动文件

vim init

-------------
#!/bin/sh
 
mount -t proc none /proc
mount -t sysfs none /sys
 
echo -e "\nBoot took $(cut -d' ' -f1 /proc/uptime) seconds\n"
 
exec /bin/sh
--------------------

chmod +x init


find . -print0  | cpio --null -ov --format=newc  | gzip -9 > $TOP/obj/initramfs-busybox-x86.cpio.gz


★★★★编译内核★★★★★★★★
linux Kernel

$ 
cd $TOP/linux-4.0.3
$ make O=../obj/linux-x86-basic x86_64_defconfig

make O=../obj/linux-x86-basic kvmconfig
#支持kvm
 make O=../obj/linux-x86-basic -j2

$ cd $TOP
运行


qemu-system-x86_64 -kernel obj/linux-x86-basic/arch/x86_64/boot/bzImage -initrd obj/initramfs-busybox-x86.cpio.gz -nographic -append "console=ttyS0" -enable-kvm


------------------------------------------------------------
i386★★★★★★★★★★如果是在64为系统上编译32位，有点特殊
------------------------------------------------------------

这步骤很重要，busybox不生成动态库

cd $TOP/busybox-1.23.2


mkdir -pv ../obj/busybox-i386
make O=../obj/busybox-i386 defconfig

make O=../obj/busybox-i386 menuconfig
-> Busybox Settings
  -> Build Options
[ ] Build BusyBox as a static binary (no shared libs)

Go to that location, select it, save, and exit.

$ cd ../obj/busybox-i386

参考
http://blog.csdn.net/xsckernel/article/details/38045783
想编译32为的环境

将/usr/bin/gcc和/usr/bin/ld都改名为*.bin，就是改为： /usr/bin/gcc.bin和/usr/bin/ld.bin
然后写两个脚本：

/usr/bin/gcc:
---------------------
#!/bin/sh  
gcc.bin -m32 $@  
------------------------
/usr/bin/ld:
------------------
#!/bin/sh  
ld.bin -m elf_i386 $@  
---------------------

还需要

yum install glibc.i686 glibc-devel.i686  glibc-static.i686 glibc-utils.x86_64 -y
yum install libgcc.i686 -y

测试是否切换到i386

--------test.c--------
#include <stdio.h>  
#include <stdlib.h>  
int main()  
{  
    printf("sizeof long is %d\n", sizeof(long));  
    return 0;  
} 
-----------------
gcc test.c

file a.out
a.out: ELF 32-bit LSB executable, 

继续以32位的方式编译busybox
$ make  -j2
$ make install


生成initramfs：

$ mkdir -p $TOP/initramfs/i386-busybox
$ cd $TOP/initramfs/i386-busybox
$ mkdir -pv {bin,sbin,etc,proc,sys,usr/{bin,sbin}}
$ cp -av $TOP/obj/busybox-i386/_install/* .

vim init
-------------
#!/bin/sh
 
mount -t proc none /proc
mount -t sysfs none /sys
 
echo -e "\nBoot took $(cut -d' ' -f1 /proc/uptime) seconds\n"
 
exec /bin/sh
--------------------
chmod +x init

find . -print0  | cpio --null -ov --format=newc  | gzip -9 > $TOP/obj/initramfs-busybox-i386.cpio.gz

--------------------------
★★★★★★编译32位的内核比较简单，只需要加ARCH=i386
--------------------------
make O=../obj/linux-i386-basic i386_defconfig
make O=../obj/linux-i386-basic kvmconfig
make O=../obj/linux-i386-basic ARCH=i386 -j16

qemu-system-i386 -kernel obj/linux-i386-basic/arch/x86/boot/bzImage -initrd obj/initramfs-busybox-i386.cpio.gz -nographic -append "console=ttyS0" -enable-kvm


-----------------------------------------------------------------------------
系统切换回64位环境
[root@jslinux mytest]# cat gcc64.sh
#!/bin/sh 
 
mv -i /usr/bin/gcc /usr/bin/gcc.sh 
mv -i /usr/bin/ld  /usr/bin/ld.sh 
 
mv -i /usr/bin/gcc.bin /usr/bin/gcc 
mv -i /usr/bin/ld.bin  /usr/bin/ld 

系统切换回32位环境

[root@jslinux mytest]# cat gcc32.sh
#!/bin/sh 
 
mv -i /usr/bin/gcc /usr/bin/gcc.bin 
mv -i /usr/bin/ld  /usr/bin/ld.bin 
 
mv -i /usr/bin/gcc.sh /usr/bin/gcc 
mv -i /usr/bin/ld.sh  /usr/bin/ld

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