Linux 内核启动分析（转）
Linux 内核启动分析
1. 内核启动地址
1.1. 名词解释
ZTEXTADDR
解压代码运行的开始地址。没有物理地址和虚拟地址之分，因为此时MMU处于关闭状态。这个地址不一定时RAM的地址，可以是支持读写寻址的flash等存储中介。
Start address of decompressor. here's no point in talking about virtual or physical addresses here, since the MMU will be off at the time when you call the decompressor code. You normally call the kernel at this address to start it booting. This doesn't have to be located in RAM, it can be in flash or other read-only or read-write addressable medium.
ZRELADDR
内核启动在RAM中的地址。压缩的内核映像被解压到这个地址，然后执行。
This is the address where the decompressed kernel will be written, and eventually executed. The following constraint must be valid:
__virt_to_phys(TEXTADDR) == ZRELADDR
The initial part of the kernel is carefully coded to be position independent.
TEXTADDR
内核启动的虚拟地址，与ZRELADDR相对应。一般内核启动的虚拟地址为RAM的第一个bank地址加上0x8000。
TEXTADDR = PAGE_OFFSET + TEXTOFFST
Virtual start address of kernel, normally PAGE_OFFSET + 0x8000.This is where the kernel image ends up. With the latest kernels, it must be located at 32768 bytes into a 128MB region. Previous kernels placed a restriction of 256MB here.
TEXTOFFSET
内核偏移地址。在arch/arm/makefile中设定。
PHYS_OFFSET
RAM第一个bank的物理起始地址。
Physical start address of the first bank of RAM.
PAGE_OFFSET
RAM第一个bank的虚拟起始地址。
Virtual start address of t
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在网上看到有人总结得不错
1．开机启动时自动运行程序
Linux
加载后, 它将初始化硬件和设备驱动, 然后运行第一个进程init。init根据配置文件继续引导过程，启动其它进程。通常情况下，修改放置
在 /etc/rc或 /etc/rc.d 或 /etc/rc?.d 目录下的脚本文件，可以使init自动启动� ......
关于linux内核中的"__attribute__ ((packed))"
来源：
http://jimmy-lee.blog.hexun.com/8001013_d.html
__attrubte__ ((packed)) 的作用就是告诉编译器取消结构在编译过程中的优化对齐,按照实际占用字节数进行对齐。
#define __u8 unsigned char
#define __u16 unsigned short
......
http://www.ic37.com/htm_tech/2008-1/7319_150547.htm
http://www.lupaworld.com/26540/viewspace-114142.html
http://www.lupaworld.com/viewnews-17909.html
http://www.lupaworld.com/26540/viewspace-117210.html
http://www.lupaworld.com/26540/spacelist-blog-itemtypeid-2105.html
http://www.lupaworld.com/ ......
翻译：飞哥 (
http://hi.baidu.com/imlidapeng
)
版权所有，尊重他人劳动成果，转载时请注明作者和原始出处及本声明。
原文名称：《Linux Performance and Tuning Guidelines》
原文地址：http://www.redbooks.ibm.com/abstracts/redp4285.html
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