Re: [PATCH 1/10] Cr4 is valid on some 486s

[Linus Torvalds]

On Sun, 13 Nov 2005, Dave Jones wrote:
> 
> Looks like the Ubuntu people already did this...

Yeah, that looks like a sane patch, although I dislike the #ifdef config 
option thing (either it works or it doesn't).

It also does it the right way: using LOCK_PREFIX means that you catch 
exactly the users that depend on SMP, and not _all_ "lock" prefixes (as 
mentioned, some of the lock prefixes are there as memory fences and are 
valid and needed even on UP). So me likee.

The only question being whether you'd actually want to nop out the 
spinlock instructions _entirely_ (in addition to changing the nops on 
things like semaphores). Without the lock, they're not that expensive, but 
hey, it's still a useless (memory-modifying) instruction.

		Linus
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