Kernel build parameter CONFIG_REGPARAM breaks binary modules

[Alan Cox]

On Thu, Mar 18, 2004 at 12:34:36AM +0100, Earle Robert Nietzel wrote:
> I patched the ATI fglrx driver so that it compiles with -mregparm=3 and
> the performance difference is noticably faster. 
> 
> I understand the reason for using fastcalls but could you explain the
> syntax implementation?
> 
> For example I know GCC uses a __attribute__((cdecl)) but the actual
> details behind this are not obvious to me.

You want to be able to use regcalls but also specify some functions
(for example functions in other languages, libraries or asm blocks)
should be called using the traditional syntax