Messages in this thread | | | Date | Wed, 5 Jul 2000 23:07:13 +0100 (BST) | From | Tigran Aivazian <> | Subject | Re: [patch] 2.4.0-test2: %cr4 in a register dump |
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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 > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.rutgers.edu > Please read the FAQ at http://www.tux.org/lkml/ >
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