Ubuntu 9.04 编译模块 "__udivdi3" undefined!

Syurato

内核编译通过了，但是编译模块的末尾提示没有"__udivdi3"
insmod提示 insmod:error inserting 'a.ko' : -1 Unknown symbol in module.
看网上的说是改内核中的Makefile加上一个选项，可是我这个是模块呀？
哪位大侠给些思路呀？没有头绪

liying_gg

你自己的模块内使用了内核里没有加载的函数。哪个模块里有__udivdi3，必须先加载后才能加载你自己的模块。

Syurato

我的文件里面没有调用他呀？
如何看哪个模块的具体名字是什么？就是lsmod的结果中的名字，对应的相应文件？

liying_gg

__udivdi3 __umoddi3 - 64 bit division in linux

If you've encountered an error message like this

Unknown symbol __udivdi3
Unknown symbol __umoddi3
Unresolved symbol __udivdi3
Unresolved symbol __umoddi3

you most likely want to make a 64 bit division, which is not supported by default in linux kernel space.


To solve this problem, you need to use the do_div macro available in asm/div64.h:

#include <asm/div64.h>
unsigned long long x, y, result;
unsigned long mod;
mod = do_div(x, y);
result = x;

If you want to calculate x / y with do_div(x, y), the result of the division is in x, the remainder is returned from the do_div function.