From: "H. Peter Anvin" <hpa@zytor.com>
To: Benjamin LaHaise <bcrl@kvack.org>
Cc: "David S. Miller" <davem@davemloft.net>,
klibc@zytor.com, linux-kernel@vger.kernel.org
Subject: Re: sys_mmap2 on different architectures
Date: Thu, 23 Feb 2006 09:47:24 -0800 [thread overview]
Message-ID: <43FDF52C.6020407@zytor.com> (raw)
In-Reply-To: <20060223173907.GF27682@kvack.org>
Benjamin LaHaise wrote:
> On Wed, Feb 22, 2006 at 04:43:47PM -0800, David S. Miller wrote:
>
>>Aha, that part I didn't catch. Thanks for the clarification
>>Ben.
>>
>>I wonder why we did things that way with a fixed shift...
>
>
> Without that trick, we'd have needed an extra parameter for the syscall
> on x86, which is already at the maximum number of registers with 6
> arguments. This was easier than changing the syscall ABI. =-)
>
Well, there is always the trick of making it a pointer. It was needed
for pselect() anyway. A real sys_mmap64 would definitely have been
cleaner, and will be needed to deal with the 16 TB barrier anyway :)
I personally think the S390 people had the right idea... once you run
out of registers, just make it a defined part of the ABI that we pass in
a single pointer to all the arguments.
-hpa
next prev parent reply other threads:[~2006-02-23 17:47 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-22 21:45 sys_mmap2 on different architectures H. Peter Anvin
2006-02-22 21:54 ` David S. Miller
2006-02-22 22:00 ` H. Peter Anvin
2006-02-23 0:05 ` H. Peter Anvin
2006-02-23 0:40 ` David S. Miller
2006-02-23 0:41 ` David S. Miller
2006-02-23 0:14 ` Benjamin LaHaise
2006-02-23 0:22 ` H. Peter Anvin
2006-02-23 0:43 ` David S. Miller
2006-02-23 0:59 ` H. Peter Anvin
2006-02-23 1:03 ` David S. Miller
2006-02-23 1:06 ` H. Peter Anvin
2006-02-23 17:39 ` Benjamin LaHaise
2006-02-23 17:47 ` H. Peter Anvin [this message]
2006-02-23 2:56 ` Paul Mackerras
2006-02-23 3:35 ` H. Peter Anvin
2006-02-23 17:32 ` Ralf Baechle
2006-02-23 17:43 ` H. Peter Anvin
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