From: Ralf Baechle <ralf@linux-mips.org>
To: Thiemo Seufer <ths@networkno.de>
Cc: Fuxin Zhang <fxzhang@ict.ac.cn>, linux-mips@linux-mips.org
Subject: Re: cmpxchg broken in some situation
Date: Wed, 3 Oct 2007 00:15:48 +0100 [thread overview]
Message-ID: <20071002231548.GA1240@linux-mips.org> (raw)
In-Reply-To: <20071002142210.GD16772@networkno.de>
On Tue, Oct 02, 2007 at 03:22:10PM +0100, Thiemo Seufer wrote:
> > +#define __cmpxchg(ptr,old,new,barrier) \
> > +({ \
> > + __typeof__(ptr) __ptr = (ptr); \
> > + __typeof__(*(ptr)) __old = (old); \
> > + __typeof__(*(ptr)) __new = (new); \
> > + __typeof__(*(ptr)) __res = 0; \
>
> Maybe we need an acquire barrier here for some systems.
Release you meant. The acquire lock would be at the end. Documentation
and actual implmeentations of cmpxchg seem to differ. It's a relativly
rarely used primitve so I think I err on the side of paranoia for now
and throw in the additional SYNC you suggest.
Ralf
next prev parent reply other threads:[~2007-10-02 23:15 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-30 10:34 cmpxchg broken in some situation Fuxin Zhang
2007-10-01 2:53 ` Ralf Baechle
2007-10-01 3:56 ` David Daney
2007-10-01 3:59 ` David Daney
2007-10-01 10:24 ` Ralf Baechle
2007-10-01 15:11 ` Fuxin Zhang
2007-10-01 15:26 ` Ralf Baechle
2007-10-02 9:34 ` Fuxin Zhang
2007-10-02 10:35 ` Ralf Baechle
2007-10-02 14:22 ` Thiemo Seufer
2007-10-02 23:15 ` Ralf Baechle [this message]
2007-10-02 22:48 ` Fuxin Zhang
2007-10-02 22:52 ` Ralf Baechle
2007-10-02 23:07 ` Fuxin Zhang
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