From: "H. Peter Anvin" <hpa@zytor.com>
To: linux-kernel@vger.kernel.org
Subject: Re: System Call parameters
Date: 16 Apr 2003 13:35:37 -0700 [thread overview]
Message-ID: <b7keqp$7p2$1@cesium.transmeta.com> (raw)
In-Reply-To: Pine.LNX.4.53.0304161256130.11667@chaos
Followup to: <Pine.LNX.4.53.0304161256130.11667@chaos>
By author: "Richard B. Johnson" <root@chaos.analogic.com>
In newsgroup: linux.dev.kernel
>
> How does the kernel get more than five parameters?
>
> Currently...
> eax = function code
> ebx = first parameter
> ecx = second parameter
> edx = third parameter
> esi = fourth parameter
> edi = fifth parameter
>
> Some functions like mmap() take 6 parameters!
> Does anybody know how these parameters get passed?
> I have an "ultra-light" 'C' runtime library I have
> been working on and, so-far, I've got everything up
> to mmap() (in syscall.h) (89 functions) working.
> I thought, maybe ebp was being used, but it doesn't
> seem to be the case.
>
%ebp is used.
However, on i386, SYS_mmap is a four-parameter system call where the
last parameter is a pointer to a parameter block. SYS_mmap2 is the
full six-parameter sane version.
You may want to check out klibc.
-hpa
--
<hpa@transmeta.com> at work, <hpa@zytor.com> in private!
"Unix gives you enough rope to shoot yourself in the foot."
Architectures needed: ia64 m68k mips64 ppc ppc64 s390 s390x sh v850 x86-64
next prev parent reply other threads:[~2003-04-16 20:23 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-16 16:58 System Call parameters Richard B. Johnson
2003-04-16 17:41 ` Bruce Harada
2003-04-16 17:58 ` Richard B. Johnson
2003-04-16 17:47 ` Bruce Harada
2003-04-16 20:35 ` H. Peter Anvin [this message]
2003-04-17 0:39 Perez-Gonzalez, Inaky
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