From: "Mike Frysinger" <vapier.adi@gmail.com>
To: "Mathieu Desnoyers" <mathieu.desnoyers@polymtl.ca>
Cc: tonyko@lineo.ca, robin.getz@analog.com, linux-kernel@vger.kernel.org
Subject: Re: blackfin - cmpxchg not atomic ?
Date: Fri, 20 Jul 2007 16:36:12 -0400 [thread overview]
Message-ID: <8bd0f97a0707201336l6bed7c24i7014333ce356417f@mail.gmail.com> (raw)
In-Reply-To: <20070720202807.GA15009@Krystal>
On 7/20/07, Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> wrote:
> I am currently passing through each architectures adding a
> cmpxchg_local() to each system.h, and I notice that you disable
> interrupts in your cmpxchg() implementation, why are you doing so ?
because Blackfin lacks any atomic instructions
> Also, does you assembly stub _really_ modify memory atomically ? If yes,
> then there should be no need for disabling interrupts. Else, I see a
> major problem with SMP.
that isnt the only problem with SMP on Blackfin
> I also don't like the comment in asm-blackfin/atomic.h :
>
> * Generally we do not concern about SMP BFIN systems, so we don't have
> * to deal with that.
>
> I have seen on the blackfin website that you actually sell a board with
> SMP. Why aren't you caring about it ?
just because a processor has more than one core does not make it SMP
-mike
next prev parent reply other threads:[~2007-07-20 20:36 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-20 20:28 Mathieu Desnoyers
2007-07-20 20:36 ` Mike Frysinger [this message]
2007-07-20 20:45 ` Mathieu Desnoyers
2007-07-20 20:59 ` Mike Frysinger
2007-07-21 7:29 ` Robert Schwebel
2007-07-21 8:37 ` Mike Frysinger
2007-07-23 17:24 ` Robin Getz
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