linux _setup()

1. system.map分析

2.__setup(str, fn)

路径：linux-3.10.x\include\linux\init.h

源码如下

/* * Only for really core code.  See moduleparam.h for the normal way. * * Force the alignment so the compiler doesn't space elements of the * obs_kernel_param "array" too far apart in .init.setup. */#define __setup_param(str, unique_id, fn, early)\static const char __setup_str_##unique_id[] __initconst\__aligned(1) = str; \static struct obs_kernel_param __setup_##unique_id\__used __section(.init.setup)\__attribute__((aligned((sizeof(long)))))\= { __setup_str_##unique_id, fn, early }#define __setup(str, fn)\__setup_param(str, fn, fn, 0)

其中obs_kernel_param如下：

struct obs_kernel_param {const char *str;int (*setup_func)(char *);int early;};

3.__setup("console=", console_setup)

路径：\linux-3.10.x\kernel\printk.c

展开如下：

#define __setup_param("console=", console_setup, console_setup, 0)\static const char __setup_str_##console_setup[] __initconst\__aligned(1) = "console="; \static struct obs_kernel_param __setup_##console_setup\__used __section(.init.setup)\//使用.init.setup保存相应的数据__attribute__((aligned((sizeof(long)))))\= { __setup_str_##console_setup, console_setup, 0 }#define __setup("console=", console_setup)\__setup_param("console=", console_setup, console_setup, 0)__setup("console=", console_setup)

所以struct obs_kernel_param为

struct obs_kernel_param {const char *str=“console”int (*setup_func)(char *)=console_setupint early=0};

所以最终会生成__setup_console_setup结构体地址，我们可以通过查看system.map表看到

c04373e0 T __setup_startc04373ec t __setup_init_setupc04373f8 t __setup_loglevelc0437404 t __setup_quiet_kernel......c0437560 t __setup_console_setup //注意这里......c0437788 T __setup_end

至此，__setup("console=", console_setup)关系已分析完！