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Re: Equivalent of ioperm / iopl in linux mips ?

To: "Maciej W. Rozycki" <macro@ds2.pg.gda.pl>
Subject: Re: Equivalent of ioperm / iopl in linux mips ?
From: Ralf Baechle <ralf@oss.sgi.com>
Date: Mon, 22 Apr 2002 10:44:17 -0700
Cc: Geert Uytterhoeven <geert@linux-m68k.org>, Wayne Gowcher <wgowcher@yahoo.com>, Linux-MIPS <linux-mips@oss.sgi.com>
In-reply-to: <Pine.GSO.3.96.1020422170125.7706H-100000@delta.ds2.pg.gda.pl>; from macro@ds2.pg.gda.pl on Mon, Apr 22, 2002 at 05:30:08PM +0200
References: <Pine.GSO.4.21.0204221654140.17279-100000@vervain.sonytel.be> <Pine.GSO.3.96.1020422170125.7706H-100000@delta.ds2.pg.gda.pl>
Sender: owner-linux-mips@oss.sgi.com
User-agent: Mutt/1.2.5.1i
On Mon, Apr 22, 2002 at 05:30:08PM +0200, Maciej W. Rozycki wrote:

>  Well, for Alpha ioperm/iopl functions check the system type in
> /proc/cpuinfo (we seem to have enough information there as well) and
> failing this they check a result of readlink of /etc/alpha_systype.  Then
> an appropriate region of /dev/mem is mmapped with per-page permissions set
> up as requested if ioperm is used (with a worse granularity, though) and
> subsequent in/out function invocations access the area as appropriate. 
> See sysdeps/unix/sysv/linux/alpha/ioperm.c in glibc for details -- it's a
> pretty clever solution with good performance and only a few trade-offs.

Thanks for volunteering ;)

  Ralf

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