From: Arnd Bergmann <arndbergmann@googlemail.com>
To: "Maciej W. Rozycki" <macro@linux-mips.org>
Cc: Andi Kleen <andi@firstfloor.org>, Dave Airlie <airlied@gmail.com>,
LKML <linux-kernel@vger.kernel.org>,
DRI Development Mailing List <dri-devel@lists.sourceforge.net>,
David Miller <davem@davemloft.net>
Subject: Re: is avoiding compat ioctls possible?
Date: Thu, 29 Oct 2009 09:27:18 +0100 [thread overview]
Message-ID: <200910290927.18436.arnd@arndb.de> (raw)
In-Reply-To: <alpine.LFD.2.00.0910282055330.9323@eddie.linux-mips.org>
On Wednesday 28 October 2009, Maciej W. Rozycki wrote:
>
> On Wed, 28 Oct 2009, Andi Kleen wrote:
>
> > > I'm just amazed that compat_ioctl should be required for all new code.
> > >
> > > DrNick on irc suggested just doing:
> > > if (is_compat_task()) ptr &= 0x00000000FFFFFFFF;
> >
> > Such hacks often have problems on BE.
>
> And then some platforms (i.e. MIPS) require sign-extension rather than
> zero-extension, that is:
>
> if (is_compat_task()) ptr = ((ptr & 0xffffffff) ^ 0x80000000) - 0x80000000;
>
> if doing this explicitly (with compat stuff hardware will do the right
> thing automagically).
Such conversion should *only* ever take place in compat_ptr().
Arnd <><
next prev parent reply other threads:[~2009-10-29 8:27 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-28 1:22 is avoiding compat ioctls possible? Dave Airlie
2009-10-28 2:25 ` David Miller
2009-10-28 3:01 ` Dave Airlie
2009-10-28 2:53 ` Andi Kleen
2009-10-28 3:05 ` Dave Airlie
2009-10-28 3:19 ` Andi Kleen
2009-10-28 3:28 ` Dave Airlie
2009-10-28 3:34 ` Andi Kleen
2009-10-28 3:43 ` David Miller
2009-10-28 3:41 ` David Miller
2009-10-28 21:05 ` Maciej W. Rozycki
2009-10-29 8:27 ` Arnd Bergmann [this message]
2009-10-28 3:38 ` David Miller
2009-10-28 3:43 ` Dave Airlie
2009-10-28 3:45 ` David Miller
2009-10-28 3:51 ` Andi Kleen
2009-10-28 3:54 ` Dave Airlie
2009-10-28 5:28 ` David Miller
2009-10-28 5:42 ` Dave Airlie
2009-10-28 6:04 ` David Miller
2009-10-28 7:53 ` David Miller
2009-10-28 7:59 ` Andi Kleen
2009-10-28 8:11 ` David Miller
2009-10-28 8:19 ` Andi Kleen
2009-10-28 8:28 ` David Miller
2009-10-28 12:13 ` Arnd Bergmann
2009-10-28 12:16 ` David Miller
2009-10-28 15:40 ` Arnd Bergmann
2009-10-29 5:41 ` David Miller
2009-10-29 8:16 ` Arnd Bergmann
2009-10-29 8:34 ` Heiko Carstens
2009-10-29 8:39 ` David Miller
2009-10-28 12:17 ` David Miller
2009-10-30 1:13 ` Dave Airlie
2009-10-30 10:13 ` Arnd Bergmann
2009-11-18 0:26 ` Dave Airlie
2009-11-18 9:09 ` Andi Kleen
2009-11-18 14:42 ` Arnd Bergmann
2009-10-28 3:37 ` David Miller
2009-10-28 4:36 ` Andi Kleen
2009-10-28 5:29 ` David Miller
2009-10-28 10:27 ` Arnd Bergmann
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