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

From: Peter Zijlstra
Date: Mon Jan 18 2010 - 07:14:51 EST


On Mon, 2010-01-18 at 14:09 +0200, Avi Kivity wrote:
> On 01/18/2010 02:06 PM, Peter Zijlstra wrote:
> > On Mon, 2010-01-18 at 14:01 +0200, Avi Kivity wrote:
> >
> >> Maybe you place no value on uprobes. But people who debug userspace
> >> likely will see a reason.
> >>
> > I do see value in uprobes, I just don't like it mucking about with the
> > address space. Nor does it appear required.
> >
>
> Well, the alternatives are very unappealing. Emulation and
> single-stepping are going to be very slow compared to a couple of jumps.

With CPL2 or RPL on user segments the protection issue seems to be
manageable for running the instructions from kernel space.

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