Re: [RFC] [PATCH 1/7] User Space Breakpoint Assistance Layer (UBP)

From: Andi Kleen
Date: Wed Jan 20 2010 - 13:33:10 EST


Peter Zijlstra <peterz@xxxxxxxxxxxxx> writes:
>
> With CPL2 or RPL on user segments the protection issue seems to be
> manageable for running the instructions from kernel space.

Nope -- it doesn't work on 64bit and even on 32bit can have large
costs on some CPUs.

Also designing 32bit only features in 2010 would seem rather ....
unfortunate.

-Andi

--
ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
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