Re: RFD: x32 ABI system call numbers

On 08/29/2011 08:04 AM, Arnd Bergmann wrote:
> 
> Right. The asm-generic/unistd.h interface doesn't provide them either
> for new architectures and expects libc to emulate them for any user
> application whose developers can't be bothered to fix their code.
> 
> I think I've also commented in the past that I think x32 should use
> the same set of syscalls asm asm-generic, even if it's more convenient
> to use a different ordering.
> 

It definitely is not convenient to use asm-generic for a whole lot of
reasons, which basically comes down to leveraging the existing x86-64
system calls plus leveraging the i386-on-x86-64 compat layer as much as
possible.

I talked to H.J. this morning and we're certainly dropping the 32-bit
filesystem calls.  I'm going to audit which paths have both time_t
(including struct timespec/timeval) and pointers; that is hopefully a
matter of legwork.  This will mean introducing new ioctls, but it's not
clear how many.

The end result is going to be bigger than the current patchset (which is
+2197 -510, and most of which is just the system call tables themselves;
the balance is only +690 -105), but it is definitely a *better* ABI.

	-hpa