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From: Arnd Bergmann <arnd@arndb.de>
To: Christoph Hellwig <hch@infradead.org>
Subject: Re: RFD: x32 ABI system call numbers
Date: Mon, 29 Aug 2011 17:04:08 +0200
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Cc: "H. Peter Anvin" <hpa@zytor.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>, "H.J. Lu" <hjl.tools@gmail.com>,
        Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>
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On Saturday 27 August 2011, Christoph Hellwig wrote:
> On Fri, Aug 26, 2011 at 05:57:34PM -0700, H. Peter Anvin wrote:
> > On 08/26/2011 05:36 PM, Linus Torvalds wrote:
> > > If you want to be compatible with "int 0x80" and old libraries, then I
> > > really don't see why you would introduce anything new.
> > 
> > Just to be clear, the reason to keep the LFS stuff in there was to be
> > compatible with the existing 32-bit *programming model*, so that a
> > program recompiled from i386 to x32 should behave the same.
> > 
> > Not that anyone should compile without -D_FILE_OFFSET_BITS=64 these days...
> 
> Any new port should not even offer non-LFS system calls.  They are a
> pain in the but, and I would sacrifice chicken if we coud stop glibc
> offering it as a default that way.

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.

	Arnd