early_param和__setup宏(二)
am *params,unsigned num_params,int (*handle_unknown)(char *param, char *val))
{
unsigned int i;
int err;
/* Find parameter */
for (i = 0; i < num_params; i++) { //num_params=0
if (parameq(param, params[i].name)) {
if (!val && params[i].ops->set != param_set_bool)
return -EINVAL;
DEBUGP("They are equal! Calling %p\n",params[i].ops->set);
mutex_lock(¶m_lock);
err = params[i].ops->set(val, ¶ms[i]);
mutex_unlock(¶m_lock);
return err;
}
}
if (handle_unknown) { //若handle_unknown函数存在
DEBUGP("Unknown argument: calling %p\n", handle_unknown);
return handle_unknown(param, val); //则调用handle_unknown函数,参数为param,val
}
DEBUGP("Unknown argument `%s'\n", param);
return -ENOENT;
}
回溯回去handle_unknow函数就是do_early_param
[cpp]
static int __init do_early_param(char *param, char *val)
{
const struct obs_kernel_param *p;
for (p = __setup_start; p < __setup_end; p++) {
if ((p->early && strcmp(param, p->str) == 0) || (strcmp(param, "console") == 0 && strcmp(p->str, "earlycon") == 0)) {
if (p->setup_func(val) != 0)
printk(KERN_WARNING"Malformed early option '%s'\n", param);
}
}
/* We accept everything at this stage. */
return 0;
}
do_early_param函数从__setup_start遍历到__setup_end段,
判断参数,进入if函数体里面
if (p->setup_func(val) != 0)这句调用了对应setup_func或early_param成员的函数,并将val作为其参数,val其实便是__setup(str, fn)或__early_param中的str
其实就是调用了fn(str)
这里的第一条if会刷选掉__setup定义的情况(除了console和earlycon参数的),因为__setup定义的obs_kernel_param结构体p->early=0
__setup定义的fn会在start_kernel->parse_args("Booting kernel", static_command_line, __start___param,__stop___param - __start___param,&unknown_bootoption);
unknown_bootoption->obsolete_checksetup函数给调用
看start_kernel中调用顺序
[cpp]
parse_early_param();
parse_args("Booting kernel", static_command_line, __start___param, __stop___param - __start___param,&unknown_bootoption);
可见先调用__early_param定义的解析参数函数及__setup定义的(console及earlycon)的参数解析函数
接着再调用__setup定义的其他解析参数函数