From: Kurt Wall <kwall@kurtwerks.com>
To: "Richard B. Johnson" <root@chaos.analogic.com>
Cc: Jamie Lokier <jamie@shareable.org>,
Linux kernel <linux-kernel@vger.kernel.org>
Subject: Re: syscall __NR_mmap2
Date: Tue, 8 Jul 2003 09:59:06 -0400 [thread overview]
Message-ID: <20030708135906.GW16938@kurtwerks.com> (raw)
In-Reply-To: <Pine.LNX.4.53.0307080749160.24488@chaos>
Quoth Richard B. Johnson:
> On Tue, 8 Jul 2003, Jamie Lokier wrote:
>
> > Richard B. Johnson wrote:
> > > mmap2(0xb8000, 8192, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_FIXED, 3, 0xb8000) = 0xb8000
> >
> > You meant to write:
> >
> > mmap2(0xb8000, 8192, PROT_READ|PROT_WRITE,
> > MAP_SHARED|MAP_FIXED, 3, 0xb8000 >> 12);
> >
> > The offset argument to mmap2 is divided by PAGE_SIZE.
> > That is the whole point of mmap2 :)
> >
> > -- Jamie
>
> Okay. Do you know where that's documented? Nothing in linux/Documentation,
> and nothing in any headers. Do you have to read the code to find out?
>
> So, the address is now the offset in PAGES, not bytes. Seems logical,
> but there is no clue in any documentation.
With the possible exception of the man mmap2 ;-)
DESCRIPTION
The function mmap2 operates in exactly the same way as
mmap(2), except that the final argument specifies the off
set into the file in units of the system page size
(instead of bytes). This enables applications that use a
--
"I have a very firm grasp on reality! I can reach out and strangle it
any time!"
next prev parent reply other threads:[~2003-07-08 13:44 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-07-07 21:00 syscall __NR_mmap2 Richard B. Johnson
2003-07-07 21:32 ` Ulrich Drepper
2003-07-08 11:56 ` Richard B. Johnson
2003-07-08 0:36 ` Jamie Lokier
2003-07-08 11:54 ` Richard B. Johnson
2003-07-08 13:59 ` Kurt Wall [this message]
2003-07-08 14:05 ` Jamie Lokier
2003-07-08 14:40 ` Richard B. Johnson
2003-07-08 14:49 ` Randy.Dunlap
2003-07-08 14:51 ` Kurt Wall
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