ubuntu上建立交叉编译环境，在qemu上运行ARM镜像

以下内容，仅供参考。如果需要详细解释的，可能不适合你花时间；如果看着Linux的命令和蹩脚英语的内容不反胃的话，您可以花点时间。

premise: 
(a) directory ~/embeddedLinux  will hold download Linux kernel, busybox, crosstool-ng
(b) directory ~/arm-busybox will hold the generated busybox root fs image
(c) directory ~/x-tools will hold the cross toolchains from crosstool-ng
(d) directory ~/ will hold the final zImage and rootfs.img.gz.
(e) qemu will be started at directory ~/



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1. download crosstool-ng 1.22.0
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ocean@ocean-bel:~$ mkdir embeddedLinux
ocean@ocean-bel:~$ ls
Desktop    Downloads      examples.desktop  Pictures  Templates  Workspace
Documents  embeddedLinux  Music             Public    Videos
ocean@ocean-bel:~$ cd embeddedLinux/
ocean@ocean-bel:~/embeddedLinux$ ls
ocean@ocean-bel:~/embeddedLinux$ wget http://crosstool-ng.org/download/crosstool-ng/crosstool-ng-1.22.0.tar.bz2
--2016-11-12 11:23:38--  http://crosstool-ng.org/download/crosstool-ng/crosstool-ng-1.22.0.tar.bz2
Resolving crosstool-ng.org (crosstool-ng.org)... 140.211.15.129
Connecting to crosstool-ng.org (crosstool-ng.org)|140.211.15.129|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 1621476 (1.5M) [application/x-bzip]
Saving to: ‘crosstool-ng-1.22.0.tar.bz2’

crosstool-ng-1.22.0 100%[===================>]   1.55M   585KB/s    in 2.7s    

2016-11-12 11:23:41 (585 KB/s) - ‘crosstool-ng-1.22.0.tar.bz2’ saved [1621476/1621476]

ocean@ocean-bel:~/embeddedLinux$ ls -al
total 1592
drwxrwxr-x  2 ocean ocean    4096 Nov 12 11:23 .
drwxr-xr-x 18 ocean ocean    4096 Nov 12 11:23 ..
-rw-rw-r--  1 ocean ocean 1621476 Nov 20  2015 crosstool-ng-1.22.0.tar.bz2
ocean@ocean-bel:~/embeddedLinux$ 
ocean@ocean-bel:~/embeddedLinux$ 
ocean@ocean-bel:~/embeddedLinux$ 
ocean@ocean-bel:~/embeddedLinux$ 
ocean@ocean-bel:~/embeddedLinux$ tar xjvf crosstool-ng-1.22.0.tar.bz2 
ocean@ocean-bel:~/embeddedLinux$ cd crosstool-ng/
ocean@ocean-bel:~/embeddedLinux/crosstool-ng$ ls
bootstrap  configure     contrib  ct-ng.comp  docs     LICENSES    Makefile.in  README.md  scripts   TODO
config     configure.ac  COPYING  ct-ng.in    kconfig  licenses.d  patches      samples    steps.mk


ocean&#