Re: [patch] 2.4.0-test2: %cr4 in a register dump

From: Linus Torvalds (torvalds@transmeta.com)
Date: Wed Jul 05 2000 - 17:10:45 EST


On Wed, 5 Jul 2000, Brian Gerst wrote:

> Linus Torvalds wrote:
> > If I remember correctly, there are CPU's out there that will bomb out
> > horribly when you access %cr4 if the register doesn't exist.
> >
> > Do I remember wrong?
> >
> > I'd certainly agree with printing out cr4 even if it would be zero, I just
> > disagree very much with adding a register read to the dump output that may
> > cause an infinite regression of traps..
> >
> > Linus
>
> How about just trapping the illegal opcode exception then? (patch
> untested)

Looks fine. Me likee, except for the fact that you should clear %0
(otherwise you'll have random crap in the "cr4" variable after a trap - I
realize that you zeroed the variable on a C source level, but gcc thinks
that your asm-statement will overwrite it, so ...)

                Linus

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