Re: [PATCH] LinuxPPS (with new syscalls API)

David Woodhouse
2007-06-27T10:18:57Z

On Wed, 2007-06-27 at 12:14 +0200, Rodolfo Giometti wrote:
> On Tue, Jun 26, 2007 at 06:38:40PM +0100, David Woodhouse wrote:
> >
> > 64-bit kernels can run 32-bit userspace programs. But some structures
> > come out _differently_ between 32-bit and 64-bit compilation, so the
> > system call needs a special 'compat' handler instead of just running the
> > normal 64-bit system call.
> >
> > The 'struct timespec' is one structure which is sometimes different for
> > 32-bit vs. 64-bit, so any system call taking a 'struct timespec' must
> > have a separate compat_sys_xxxx() to handle that. See something like
> > compat_sys_clock_settime() in kernel/compat.c for an example (but don't
> > use set_fs() like it does; just see how it handles the compat_timespec).
>
> Did you mean something like this?

How will 64-bit system calls work if you do it like that? You need to
provide _both_ sys_time_pps_fetch() and compat_sys_time_pps_fetch().

--
dwmw2