Re: Missing cache flush.

[Alan Cox]

>  - it is buggy and will lock up some CPU's. Use with EXTREME CAUTION.
>    Intel set a special field in the MP table for whether wbinval is
>    usable or not, and you can probably find their errata on which CPU's
>    it doesn't work on (I think it was some early PPro steppings).

Also some intel chipsets it didnt work with (notably earlier PCI ones) - indeed
that seems to be the cause of the 'bzImage wont boot on XYZ 486 tosh
laptop' bug.

> On the whole, I would suggest avoiding this like the plague, and just
> marking such memory to be non-cacheable, regardless of whether there is
> a performance impact or not. If you mark it write-combining and
> speculative, it's going to perform a bit better.

Or memcpy the blocks into the block or page cache when you need them.