Re: [patch] i386: make bitops safe

[Linus Torvalds]

On Mon, 27 Feb 2006, Chuck Ebbert wrote:
>
> Make i386 bitops safe.  Currently they can be fooled, even on
> uniprocessor, by code that uses regions of the bitmap before
> invoking the bitop.  The least costly way to make them safe
> is to add a memory clobber and tag all of them as volatile.

Actually, the least costly way should be to make the "ADDR" define work 
right again.

It used to do something magic like

	struct fake_area {
		unsigned long members[1000];
	};

	#define ADDR (*(volatile struct fake_area *)addr)

which was correct. I forget why it got broken into using just a "long *" 
(it happened a long long time ago).

		Linus
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