Messages in this thread | | | Date | Fri, 29 Mar 1996 09:44:40 +0200 (EET) | From | Linus Torvalds <> | Subject | Re: [Q] Cyrix/IBM 6x86 ? |
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On Wed, 27 Mar 1996, Alan Cox wrote: > > in HLT, otherwise 3.6 A and more. (sic!) Things like "Data forwarding", > > "Fill on Write Miss", "Write Gathering", "Weak Ordering" etc. are powerful > > options which aren't supported by Pentiums, and you have to enable them > > Weak ordering if its doing write re-ordering will need to go on/off as you > access stuff like WD80x3 ethernet cards. The other stuff ought to be ok on > the whole. Try it and see - you can access 22h/23h from a root program with > ioperm().
I'd assume that the 6x86 has a few "range" registers to mark _which_ areas of memory can be weakly ordered. That's how the PPro does it, and it's the only sane way to go (alternatively you can do it on a page-table basis, that's fine too and has some other advantages).
Anyway, the way to do all this is to make a loadable module that sets up the registers and then exists (the IO ports you can do from user space, but any control registers probably need the module approach anyway)
Linus
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