Re: [PATCH v11 25/25] x86/cet/shstk: Add arch_prctl functions for shadow stack

[Yu, Yu-cheng]

On 9/1/2020 10:50 AM, Florian Weimer wrote:
> * Yu-cheng Yu:
>
> > Like other arch_prctl()'s, this parameter was 'unsigned long'
> > earlier. The idea was, since this arch_prctl is only implemented for
> > the 64-bit kernel, we wanted it to look as 64-bit only.  I will change
> > it back to 'unsigned long'.
>
> What about x32?  In general, long is rather problematic for x32.

The problem is the size of 'long', right?
Because this parameter is passed in a register, and only the lower bits 
are used, x32 works as well.