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SubjectRe: [patch] 2.4.0-test2: %cr4 in a register dump
but Jeff, his trapping patch was so beautiful and elegant! (if only I
understood how it works... - presumably the same principle as described
in Documentation/exception.txt)

Regards,
Tigran

On Wed, 5 Jul 2000, Jeff V. Merkey wrote:

>
> How about just checking the feature flags to see if debugging extensions
> are present (IO breakpoints) which always means that a valid CR4
> register is present (since the bit to enable IO breakpoints in located
> in CR4). Then the patch will work accross all Pentium class processors
> and you won't need the trap .....
>
> :-)
>
> Jeff
>
> 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)
> >
> > --
> >
> > Brian Gerst
> >
> > ------------------------------------------------------------------------
> > Name: cr4.diff
> > cr4.diff Type: application/x-unknown-content-type-diff_auto_file
> > Encoding: base64
>
> -
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