Re: error: no previous prototype for ‘pt_regs_check’

[Christophe LEROY]

Mathieu,

Le 07/12/2018 à 21:07, Mathieu Malaterre a écrit :
> Michael,
> 
> I have been wondering for a while now, but I failed to make sense of
> this function: pt_regs_check (commit 002af9391bfbe). What is this
> function meant for ?

AFAICS this is a dummy function, its purpose is to break the build if 
struct pt_regs and struct user_pt_regs don't match.

> 
> Background, it breaks my W=1 build with:
> 
> ../arch/powerpc/kernel/ptrace.c:3339:13: error: no previous prototype
> for ‘pt_regs_check’ [-Werror=missing-prototypes]

What about adding a prototype for it on the line above ?

> 
> I failed to find a usage of it within the linux source tree... (git
> grep pt_regs_check returns nothing).

This function has no functionnal purpose, and will get eliminated at 
link time or after init depending on CONFIG_LD_DEAD_CODE_DATA_ELIMINATION


Christophe
> 
> Thanks,
>