From: Andi Kleen <[EMAIL PROTECTED]> Date: 02 Sep 2005 22:41:31 +0200
> > Yeah quite a few. I suspect most MIPS also would have a problem in this > > area. > > cmpxchg can be done with LL/SC can't it? Any MIPS should have that. Right. On PARISC, I don't see where they are emulating compare and swap as indicated. They are doing the funny hashed spinlocks for the atomic_t operations and bitops, but that is entirely different. cmpxchg() has to operate in an environment where, unlike the atomic_t and bitops, you cannot control the accessors to the object at all. The DRM is the only place in the kernel that requires cmpxchg() and you can thus make a list of what platform can provide cmpxchg() by which ones support DRM and thus provide the cmpxchg() macro already in asm/system.h We really can't require support for this primitive kernel wide, it's simply not possible on a couple chips. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
