kernel文件结构，makefile与kconfig机制分析
以下分析均来自于kernel 2.6.35.7版本
一、目录结构
| Name | Description |
|---|---|
| arch | 架构相关 |
| block | 块设备管理 |
| crypto | 加密算法 |
| drivers | 驱动 |
| firmware | 固件 |
| fs | 文件系统 |
| include | 头文件 |
| init | 初始化 |
| ipc | 进程间通讯 |
| kernel | 内核 |
| lib | 相关库 |
| net | 网络 |
| mm | 内存管理 |
| scripts | 脚本 |
| security | 安全 |
| sound | 音频处理 |
| tools | 常用工具 |
| usr | 与linux内核启动相关 |
| virt | 内核虚拟机 |
二、配置
配置分为三步进行
x210ii_qt_defconfig
根据特定架构利用arch/$ARCH/configs/${PLATFORM}_defconfig在根目录中创建.config。
"make defconfig"
Create a ./.config file by using the default symbol values from either arch/$ARCH/defconfig or arch/$ARCH/configs/${PLATFORM}_defconfig, depending on the architecture. .config文件是编译的关键。
menuconfig
"make menuconfig"
Text based color menus, radiolists & dialogs.三、Kconfig
几乎所有文件夹下都有Kconfig这个文件。那么这个文件究竟用来做什么呢？
这与menuconfig有关。scripts\kconfig\lxdialog目录下的一些c文件就是用来提供menuconfig的那些程序源代码。而menuconfig中的配置项全部来自于每个目录下的Kconfig。
文件格式
menuconfig NETDEVICES
default y if UML
depends on NET
bool "Network device support"
---help---
You can say N here if you don't intend to connect your Linux box to
any other computer at all.
You'll have to say Y if your computer contains a network card that
you want to use under Linux. If you are going to run SLIP or PPP over
telephone line or null modem cable you need say Y here. Connecting
two machines with parallel ports using PLIP needs this, as well as
AX.25/KISS for sending Internet traffic over amateur radio links.
See also "The Linux Network Administrator's Guide" by Olaf Kirch and
Terry Dawson. Available at <http://www.tldp.org/guides.html>.
If unsure, say Y.
# All the following symbols are dependent on NETDEVICES - do not repeat
# that for each of the symbols.
if NETDEVICES
config IFB
tristate "Intermediate Functional Block support"
depends on NET_CLS_ACT
---help---
This is an intermediate driver that allows sharing of
resources.
To compile this driver as a module, choose M here: the module
will be called ifb. If you want to use more than one ifb
device at a time, you need to compile this driver as a module.
Instead of 'ifb', the devices will then be called 'ifb0',
'ifb1' etc.
Look at the iproute2 documentation directory for usage etc menuconfig表示当前显示的目录层级，属于bool中的字符串。
config表示当前目录下的可配置项。
tristate表示三态，bool表示两态。
depends表示依赖关系
关系
menuconfig中的菜单项来自于Kconfig中的配置。经过menuconfig后，被修改的选项会保存到.config中，最终导致Makefile的编译变化。
