blackfin - cmpxchg not atomic ?

From: Mathieu Desnoyers
Date: Fri Jul 20 2007 - 16:28:21 EST


Hello,

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 ?
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.

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 ?

Mathieu

--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
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