Re: Rust kernel policy

[Steven Rostedt]

On Fri, 21 Feb 2025 19:23:38 +0100
Martin Uecker <uecker@xxxxxxxxx> wrote:

> > where func is defined as:
> > 
> > 	void func(void) { return ; }  
> 
> Calling a function declared in this way with arguments
> would be rejected by the compiler, so I am not sure how
> this works now.
> 
> If you used 
> 
> void func();
> 
> to declare the function, this is not possible anymore in C23.

As the comment in the code states:

include/linux/static_call.h:

 *   This feature is strictly UB per the C standard (since it casts a function
 *   pointer to a different signature) and relies on the architecture ABI to
 *   make things work. In particular it relies on Caller Stack-cleanup and the
 *   whole return register being clobbered for short return values. All normal
 *   CDECL style ABIs conform.

Basically it's assigned via casts.

-- Steve