From: Arnd Bergmann <arnd@arndb.de>
To: "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: X32 psABI status
Date: Sun, 13 Feb 2011 23:28:14 +0100
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Cc: x32-abi@googlegroups.com, "H.J. Lu" <hjl.tools@gmail.com>,
        GCC Development <gcc@gcc.gnu.org>,
        GNU C Library <libc-alpha@sourceware.org>,
        LKML <linux-kernel@vger.kernel.org>,
        "H. Peter Anvin" <hpa@linux.intel.com>
References: <AANLkTikgfv+L9WS4s6n5mQcXWTzc6YMNUSsgBiAOmKbE@mail.gmail.com> <AANLkTimZA1Npf0nJ8PF-2=8Oe2LXr_ShyBJNkf8Dn5S5@mail.gmail.com> <4D584A49.80306@zytor.com>
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On Sunday 13 February 2011, H. Peter Anvin wrote:
> The actual idea is to use the i386 compat ABI for memory layout, but
> with a 64-bit register convention.  That means that system calls that
> don't make references to memory structures can simply use the 64-bit
> system calls, otherwise we're planning to reuse the i386 compat system
> calls, but invoke them via the syscall instruction (which requires a new
> system call table) and to pass 64-bit arguments in single registers.

As far as I know, any task can already call both the 32 and 64 bit syscall
entry points on x86. Is there anything you can't do just as well by
using a combination of the two methods, without introducing a third one?

	Arnd
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