Subject: Re: [PATCH] LinuxPPS (with new syscalls API)
From: David Woodhouse <dwmw2@infradead.org>
To: Rodolfo Giometti <giometti@enneenne.com>
Cc: linux-kernel@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>
In-Reply-To: <20070627101449.GH13886@enneenne.com>
References: <20070626100628.GO24183@enneenne.com>
	 <1182855427.12109.203.camel@pmac.infradead.org>
	 <20070626170622.GA13886@enneenne.com>
	 <1182879520.3263.19.camel@shinybook.infradead.org>
	 <20070627101449.GH13886@enneenne.com>
Content-Type: text/plain
Date: Wed, 27 Jun 2007 11:18:30 +0100
Message-Id: <1182939510.6409.17.camel@pmac.infradead.org>
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1202
Lines: 27

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

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/