Re: Problems compiling kernel modules

[Lei Yang <leiyang@nec-labs.com>]

Richard B. Johnson wrote:
> On Mon, 23 Aug 2004, Lei Yang wrote:
> 
> 
>>Richard B. Johnson wrote:
>>
>>
>>>Do `depmod -e test.ko` to see what it's complaining about. You
>>>can see all the symbols by using `nm`. Try it. Your code
>>>probably didn't define the necessary stuff to make a module.
>>>You need to look at a typical module (driver) that comes with the
>>>kernel. Just find one of the shortest ".c" files in the driver
>>>tree.
>>
>>Thanks! I did less /var/log/messages, and got the unknown symbols
>>Unknown symbol __divsf3
>>Unknown symbol __fixsfsi
>>Unknown symbol __subsf3
>>Unknown symbol __floatsisf
>>Unknown symbol __mulsf3
>>Unknown symbol __gesf2
>>Unknown symbol __addsf3
>>
>>However, I don't know what those symbols are :( I am a bit worried that
>>maybe I've done something that is not supported by the kernel, like
>>left-shift 16 bits of an int, or floating operations.
>>
>>Any hints?
>>
>>Thanks a lot!
>>Lei
> 
> 
> You cannot use floating-point in the kernel. It appears that you
> are trying to make user-mode code execute within the kernel. It
> can't. That's not what a module does. The kernel executes code
> on behalf of the user-mode caller, in the context of the caller.
> It does things, on behalf of the user, that the user can't
> be trusted to do properly by himself. That's all the kernel
> is for! Any calculations and similar stuff can be done in
> regular user-mode code.

Sort of, I am trying to make a usr mode library work with kernel. 
However, floating point operation is necessary in the algorithm. You 
mean that this can never be done? Is changing floating-point the only 
thing I can do now?

Thanks!
Lei

> Cheers,
> Dick Johnson
> Penguin : Linux version 2.4.26 on an i686 machine (5570.56 BogoMips).
>             Note 96.31% of all statistics are fiction.
> 
>