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Date: Sun, 13 Feb 2011 13:28:25 -0800
Message-ID: <AANLkTikbFM5BjcD1=KsO-tHpHn-01Sxnqp40_GtbifYY@mail.gmail.com>
Subject: Re: X32 psABI status
From: "H.J. Lu" <hjl.tools@gmail.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: x32-abi@googlegroups.com, Arnd Bergmann <arnd@arndb.de>,
        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>
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On Sun, Feb 13, 2011 at 1:16 PM, H. Peter Anvin <hpa@zytor.com> wrote:
> On 02/13/2011 01:10 PM, H.J. Lu wrote:
>>> The basic concept looks entirely reasonable to me, but I'm
>>> curious what drove the decision to start out with the x86_64
>>> system calls instead of the generic ones.
>>>
>>> Since tile was merged, we now have support for compat syscalls
>>> in the generic syscall ABI. I would have assumed that it
>>> was possible to just use those if you decide to do a new
>>> ABI in the first place.
>>>
>>> The other option that would have appeared natural to me is
>>> to just use the existing 32 bit compat ABI with the few
>>> necessary changes done based on the personality.
>
> 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.
>

That is is currently implemented on hjl/x32 branch.

I also added

__NR_sigaction
__NR_sigpending
__NR_sigprocmask
__NR_sigsuspend

to help the Bionic C library.


-- 
H.J.
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