Re: [PATCH -v2 1/4] Add Kconfig option ARCH_HAVE_NMI_SAFE_CMPXCHG

[Russell King - ARM Linux]

On Thu, Apr 07, 2011 at 09:29:03AM +0800, Huang Ying wrote:
> cmpxchg() is widely used by lockless code, including NMI-safe lockless
> code.  But on some architectures, the cmpxchg() implementation is not
> NMI-safe, on these architectures the lockless code may need to a
> spin_trylock_irqsave() based implementation.
> 
> This patch adds a Kconfig option: ARCH_HAVE_NMI_SAFE_CMPXCHG, so that
> NMI-safe lockless code can depend on it or provide different
> implementation according to it.
> 
> On many architectures, cmpxchg is only NMI-safe for several specific
> operand sizes. So, ARCH_HAVE_NMI_SAFE_CMPXCHG define in this patch
> only guarantees cmpxchg is NMI-safe for sizeof(unsigned long).

As this no longer touches any ARM code, I thinky you can drop me from the
CC list.  Thanks.
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