(一). 定义如下:
#define __setup(str, fn) \
__setup_param(str, fn, fn, 0)
#define __setup_param(str, unique_id, fn, early) \
static char __setup_str_##unique_id[] __initdata __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 }
struct obs_kernel_param {
const char *str;
int (*setup_func)(char *);
int early;
};
(二). 例子:(来源于:net/core/dev.c)
__setup(“netdev=”, netdev_boot_setup)`
由(一)可转换为:
__setup_param("netdev=", netdev_boot_setup, netdev_boot_setup, 0)
=====>
#define __setup_param("netdev=", netdev_boot_setup, netdev_boot_setup, 0) \
static char __setup_str_netdev_boot_setup[] __initdata __aligned(1) = "netdev="; static struct obs_kernel_param __setup_unique_id __used __section(.init.setup) __attribute__((aligned((sizeof(long))))) = { __setup_str_unique_id, netdev_boot_setup, 0 }
__setup(str, fn)
str是关键字,fn是关联处理函数。__setup只是告诉内核在启动时输入串中含有str时,内核要去执行fn。str必须以“=”符结束以使parse_args更方便解析。紧随“=”后的任何文本都会作为输入传给 fn。
++++++++++++++++++++++++++++++++++++++++++++++++++++++++
继续拿__setup(“netdev=”, netdev_boot_setup)举例:
要实现netdev_boot_setup,哪它以什么样的形式出现呢?:
struct obs_kernel_param {
const char *str;
int (*setup_func)(char *);
int early;
};
应以这样的形式去实现:
int netdev_boot_setup(char *str)
{
...
retutn 0;
}
当内核启动解析参数时有“netdev”字符串时就会执行netdev_boot_setup函数并将“netdev=”后的字符串当做参数传入。
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时间: 2024-10-13 19:34:15