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@ocean-bel:~/embeddedLinux/crosstool-ng$ sudo apt-get install ncurses-dev bison texinfo flex autoconf automake libtool libexpat1-dev libncurses5-dev patch curl cvs build-essential subversion gawk python-dev gperf
ocean@ocean-bel:~/embeddedLinux/crosstool-ng$ ./configure --enable-local
ocean@ocean-bel:~/embeddedLinux/crosstool-ng$ make
ocean@ocean-bel:~/embeddedLinux/crosstool-ng$ ls
bootstrap config.log configure.ac ct-ng docs licenses.d patches README.md steps.mk
config config.status contrib ct-ng.comp kconfig Makefile paths.mk samples TODO
config.gen configure COPYING ct-ng.in LICENSES Makefile.in paths.sh scripts
ocean@ocean-bel:~/embeddedLinux/crosstool-ng$
ocean@ocean-bel:~/embeddedLinux/crosstool-ng$ ./ct-ng help
ocean@ocean-bel:~/embeddedLinux/crosstool-ng$ ./ct-ng list-samples
Status Sample name
MKDIR config.gen
IN config.gen/arch.in
IN config.gen/kernel.in
IN config.gen/cc.in
IN config.gen/binutils.in
IN config.gen/libc.in
IN config.gen/debug.in
[L..] alphaev56-unknown-linux-gnu
[L..] alphaev67-unknown-linux-gnu
[L..] arm-bare_newlib_cortex_m3_nommu-eabi
[L..] arm-cortex_a15-linux-gnueabi
[L.X] arm-cortexa5-linux-uclibcgnueabihf
[L..] arm-cortex_a8-linux-gnueabi
[L.X] arm-cortexa9_neon-linux-gnueabihf
[L..] armeb-unknown-eabi
[L..] armeb-unknown-linux-gnueabi
[L..] armeb-unknown-linux-uclibcgnueabi
[L..] arm-unknown-eabi
[L..] arm-unknown-linux-gnueabi
[L.X] arm-unknown-linux-musleabi
[L..] arm-unknown-linux-uclibcgnueabi
[L.X] arm-unknown-linux-uclibcgnueabihf
[L..] armv6-rpi-linux-gnueabi
[L..] armv7-rpi2-linux-gnueabihf
[L..] avr
[L..] i586-geode-linux-uclibc
[LB.] i586-mingw32msvc,i686-none-linux-gnu
[L..] i686-nptl-linux-gnu
[L.X] i686-w64-mingw32
[L..] m68k-unknown-elf
[L..] m68k-unknown-uclinux-uclibc
[L..] mips64el-n32-linux-uclibc
[L..] mips64el-n64-linux-uclibc
[L..] mips-ar2315-linux-gnu
[L..] mipsel-sde-elf
[L..] mipsel-unknown-linux-gnu
[L..] mips-malta-linux-gnu
[L..] mips-unknown-elf
[L..] mips-unknown-linux-uclibc
[L.X] i686-w64-mingw32,nios2-spico-elf
[L..] powerpc-405-linux-gnu
[L..] powerpc64-unknown-linux-gnu
[L..] powerpc-860-linux-gnu
[L..] powerpc-e300c3-linux-gnu
[L..] powerpc-e500v2-linux-gnuspe
[L..] powerpc-unknown-linux-gnu
[LB.] powerpc-unknown-linux-uclibc
[L..] powerpc-unknown_nofpu-linux-gnu
[L.X] s390-ibm-linux-gnu
[L..] s390x-ibm-linux-gnu
[L..] sh4-unknown-linux-gnu
[L..] sparc-unknown-linux-gnu
[L.X] x86_64-w64-mingw32,x86_64-pc-linux-gnu
[L..] x86_64-unknown-linux-gnu
[L..] x86_64-unknown-linux-uclibc
[L.X] x86_64-w64-mingw32
[L..] xtensa-unknown-linux-uclibc
L (Local) : sample was found in current directory
G (Global) : sample was installed with crosstool-NG
X (EXPERIMENTAL): sample may use EXPERIMENTAL features
B (BROKEN) : sample is currently broken
ocean@ocean-bel:~/embeddedLinux/crosstool-ng$ ./ct-ng arm-unknown-linux-uclibcgnueabi
IN config.gen/arch.in
IN config.gen/kernel.in
IN config.gen/cc.in
IN config.gen/binutils.in
IN config.gen/libc.in
CONF config/config.in
#
# configuration written to .config
#
***********************************************************
Initially reported by: Thomas Petazzoni
URL: https://plus.google.com/+ThomasPetazzoni
***********************************************************
Now configured for "arm-unknown-linux-uclibcgnueabi"
ocean@ocean-bel:~/embeddedLinux/crosstool-ng$
ocean@ocean-bel:~/embeddedLinux/crosstool-ng$ ./ct-ng menuconfig
--> Paths and misc options
---> Local tarballs directory (default is ${HOME}/src)
---> Prefix directory (default the Prefix directory will be ${HOME}/x-tools/${CT_TARGET})
---> Maximum log level to see: DEBUG
--> Toolchain options
---> Tuple's alias: arm-linux
--> Debug facilities
* do not select 'dmalloc' and 'duma'. select 'gdb', 'ltrace' and 'strace'
---> gdb: do not select 'cross-gdb' and 'native-gdb'. select 'gdbserver' and 'Build a static gdbserver'
Save and Exit. The .config file will be saved.
ocean@ocean-bel:~/embeddedLinux/crosstool-ng$ pwd
/home/ocean/embeddedLinux/crosstool-ng
ocean@ocean-bel:~/embeddedLinux/crosstool-ng$ ls
bootstrap config.log configure.ac ct-ng docs licenses.d patches README.md steps.mk
config config.status contrib ct-ng.comp kconfig Makefile paths.mk samples TODO
config.gen configure COPYING ct-ng.in LICENSES Makefile.in paths.sh scripts
ocean@ocean-bel:~/embeddedLinux/crosstool-ng$ ./ct-ng build
Note: the cross tool chains will be found at /home/ocean/x-tools
---add cross toolchains to the source file /etc/bash.bashrc
ocean@ocean-bel:~$ vi /etc/bash.bashrc
...
# Added path for cross compiling toolchains
export PATH=$PATH:/home/ocean/x-tools/arm-unknown-linux-uclibcgnueabi/bin
ocean@ocean-bel:~$ source /etc/bash.bashrc
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2. download linux kernel from kernel.org and use 'vexpress_defconfig'
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(1) download linux kernel from kernel.org
wget https://www.kernel.org/pub/linux/kernel/v4.x/linux-4.8.4.tar.gz
(2) use vexpress_defconfig
ocean@ocean-bel:~/embeddedLinux/linux-4.8.4$ make vexpress_defconfig ARCH=arm CROSS_COMPILE=arm-linux-
HOSTCC scripts/basic/fixdep
HOSTCC scripts/kconfig/conf.o
SHIPPED scripts/kconfig/zconf.tab.c
SHIPPED scripts/kconfig/zconf.lex.c
SHIPPED scripts/kconfig/zconf.hash.c
HOSTCC scripts/kconfig/zconf.tab.o
HOSTLD scripts/kconfig/conf
#
# configuration written to .config
#
Note: the vexpress_defconfig can be found under linux-4.8.4/arch/arm/configs/
(3) build kernel
ocean@ocean-bel:~/embeddedLinux/linux-4.8.4$ make all ARCH=arm CROSS_COMPILE=arm-linux- CONFIG_DEBUG_INFO=y
(4) find the generated zImage under arch/arm/boot/
ocean@ocean-bel:~/embeddedLinux/linux-4.8.4/arch/arm/boot$ ls
bootp dts Image initramfs Makefile
compressed hello.c init install.sh zImage
(5) copy zImage to ~/
ocean@ocean-bel:~$ cp embeddedLinux/linux-4.8.4/arch/arm/boot/zImage .
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3. build busybox
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(1) download busybox
ocean@ocean-bel:~$ wget http://busybox.net/downloads/busybox-1.25.1.tar.bz2
(2) use 'defconfig'
ocean@ocean-bel:~$ make ARCH=arm CROSS_COMPILE=arm-linux- defconfig
(3) make menuconfig and set option to set busybox as a static binary
ocean@ocean-bel:~$ make ARCH=arm CROSS_COMPILE=arm-linux- menuconfig
--> Busybox Settings ---> Build Options ---> [*] Build BusyBox as a static binary (no shared libs)
--> Networking Utilities ---> []Enable IPv6 support
---> []nslookup
(4) build busybox and put the generated busybox files to '/home/ocean/arm-busybox'
ocean@ocean-bel:~$ make CONFIG_PREFIX=/home/ocean/arm-busybox ARCH=arm CROSS_COMPILE=arm-linux- install
(5) locate at directory '/home/ocean/arm-busybox'
ocean@ocean-bel:~/arm-busybox$ pwd
/home/ocean/arm-busybox
(a) mkdir -p proc sys dev etc etc/init.d
(b) create file etc/init.d/rcS
ocean@ocean-bel:~/arm-busybox/etc/init.d$ ls -al
total 12
drwxrwxr-x 2 ocean ocean 4096 Nov 13 20:21 .
drwxrwxr-x 3 ocean ocean 4096 Nov 12 17:20 ..
-rwxrwxr-x 1 ocean ocean 154 Nov 13 20:21 rcS
ocean@ocean-bel:~/arm-busybox/etc/init.d$ cat rcS
#!/bin/sh
mount -t proc none /proc
mount -t sysfs none /sys
echo -e "\n Boot took $(cut -d '' -f1 /proc/uptime) seconds\n"
/sbin/mdev -s
#exec /bin/sh
(c) chmod +x etc/init.d/rcS
(6) create root fs image file and generate rootfs.img.gz to ~/
--commands to generate the fs image file-----
find . | cpio -o --format=newc > ../rootfs.img
cd ..
gzip -c rootfs.img > rootfs.img.gz
----------------------------------------------
ocean@ocean-bel:~/arm-busybox$ pwd
/home/ocean/arm-busybox
ocean@ocean-bel:~/arm-busybox$ ls
bin dev etc linuxrc proc sbin sys usr
ocean@ocean-bel:~/arm-busybox$ find . | cpio -o --format=newc > ../rootfs.img
2265 blocks
ocean@ocean-bel:~/arm-busybox$ cd ..
ocean@ocean-bel:~$ gzip -c rootfs.img > rootfs.img.gz
ocean@ocean-bel:~$ ls
arm-busybox Downloads Music rootfs.img Videos
Desktop embeddedLinux Pictures rootfs.img.gz x-tools
Documents examples.desktop Public Templates zImage
ocean@ocean-bel:~$
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4. start qemu
ref link: http://ronubo.blogspot.be/2016/02/linux-on-arm-emulator-bringup-building.html
notes: in the kernel 4.x version, qemu should be passed with
dtb (which is built from the correspondig
arch/arm/boot/dts/<your_board_variant>.dts)
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For vexpress board:
qemu-system-arm -M vexpress-a9 -m 512M -kernel zImage -initrd rootfs.img.gz -serial stdio -append "root=/dev/ram rdinit=/bin/sh console=tty1" -dtb /home/ocean/embeddedLinux/linux-4.8.4/arch/arm/boot/dts/vexpress-v2p-ca9.dtb