第一次进入保护模式,解压缩内核
startup_32: //head.S (c:\linux\linux-2.6.23\arch\i386\boot\compressed)
=>//Do the decompression, and jump to the new kernel..
=> Jump to the decompressed kernel.
跳转到解压缩内核之后,使能页模式
里面有一个重要的宏定义:
[linux-2.6.23]$ cat .config | grep CONFIG_PAGE_OFFSET
CONFIG_PAGE_OFFSET=0xC0000000
[linux-2.6.23]$
ENTRY(startup_32) //head.S (c:\linux\linux-2.6.23\arch\i386\kernel)
=>Copy bootup parameters out of the way. //主要是boot_params
=>// Initialize page tables
=>//Enable paging
=>call setup_idt
=>je is386
=>jmp start_kernel