LDD knowledge sorting

Hello everyone , I meet you again , I'm your friend, Quan Jun .

Learning summary ：

1、 Learn the documentation that comes with the kernel

I read the documentation in the kernel yesterday ：

README
Documentation/HOWTO

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I learned a lot . Got a website http://kernelnewbies.org, some FAQ , Below are

(1) Code Browsing

a) cscope,tags

The original kernel has generated cscope and tags Script for

make cscope
make tags

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to make add V=1, You can see which commands are executed .

$ make cscope V=1
  /bin/bash linux-2.6.32.63/scripts/tags.sh cscope
.....
+ cscope -b -f cscope.out

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You can see that the call is scripts/tags.sh This script .

b) find + grep

Find the structure definition

find . -name ‘*.[chS]’ | xargs grep -EnH “\W*struct\W+task_struct\W*{“

Find the function definition

find . -name ‘*.[chS]’ | xargs grep -EnH “cdev_init\W*\(struct cdev”

notes ： find The command is used to determine the type of file to look for , Look here for .c .h .S( assembly ) file .

xargs More critical , Without him , unable Run correctly , It takes the output of the previous command as an argument to the following command .（ A pipeline is one that takes the previous output as the subsequent input stdin.）

grep -E Indicates the use of regular expressions . \W Represents a white space character , * Indicates that the preceding character appears 0 Times or times

c) lxr （ Good website ）

http://lxr.oss.org.cn/

2、 Get ready ’ console ’

The written driver needs insmod To test . You can prepare a virtual machine for learning driven development . Think of it as your game console ！

download fedora 12. use virtual box Install as a virtual machine . Then download the kernel you want to study . I downloaded it 2.6.32

Then compile and install your kernel . After success , Take this kernel as the source tree , Then write the driver , Enjoy insmod Well

（ It turns out that the driver is verified on the development board , however LDD3 When the example of does not involve specific hardware , You can use this virtual machine . But how can a real driver not deal with hardware , So finally, you must write a driver for the development board , The most important thing is to put theory into practice ！）

Compile and install kernel reference ：

http://blog.chinaunix.net/uid-26497520-id-3593098.html

http://lesca.me/archives/config-and-install-kernel.html

initrd.img and System.map

http://www.cnblogs.com/parrynee/archive/2010/05/13/1734791.html

download , After decompressing the kernel .

  cd linux-2.6.32
  cp /boot/config-`uname -r` ./.config
  make menuconfig
  make
  make modules
  sudo make install
  sudo make modules_install

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Change the virtual machine run level to text mode ： modify /etc/inittab file

id:3:initdefault:

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Use ssh Log in to the virtual machine . ssh ip Address .

Use screen To manage the call back , Very convenient .

3、 Write driver

The written driver code is put into github, Then write a summary page , Put the link here

Hello World

4、 Kernel source code analysis

Distribute driver related or other kernel source code

alloc_chrdev_region

copy_to_user and copy_from_user

Learning materials ：

1、LDD3 book

english ：

http://lwn.net/Kernel/LDD3/

chinese ：

http://oss.org.cn/kernel-book/ldd3/index.html

thank Author and open source China oss.org.cn

2、 The code download

kernel 2.6.X http://examples.oreilly.com/9780596005900/

kernel 3.x https://github.com/kerneltravel/ldd3-examples-3.x

other： https://github.com/4get/ldd3_examples

Publisher ： Full stack programmer stack length , Reprint please indicate the source ：https://javaforall.cn/132879.html Link to the original text ：https://javaforall.cn