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)  //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)

所以struct obs_kernel_param为

 

 

struct obs_kernel_param {
  const char *str=“console”
  int (*setup_func)(char *)=console_setup
  int 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_start
c04373ec t __setup_init_setup
c04373f8 t __setup_loglevel
c0437404 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！