Messages in this thread | | | Date | Fri, 25 Sep 2009 03:35:13 -0400 | From | Mathieu Desnoyers <> | Subject | Re: Immediate values |
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* Arjan van de Ven (arjan@infradead.org) wrote: > On Thu, 24 Sep 2009 21:34:22 +0200 > Ingo Molnar <mingo@elte.hu> wrote: > [context for people CCed: see http://lkml.org/lkml/2009/9/24/262]
> > > > * H. Peter Anvin <hpa@zytor.com> wrote: > > > > > I would like to get an official ACK or NAK for this patching > > > technique from inside Intel, and preferrably from AMD as well. If > > > it does work as described it would provide a very clean way to do > > > one-shot alternative functions, which probably would be higher > > > value than immediate data values. > > > > Sounds tempting. Things like the CONFIG_SECURITY hookery could use it? > > > > But ... since it's patched under stopmachine, is there any reason why > > this wouldnt work? > > > > stopmachine is fine. > > more aggressive tricks are rather dicey. > > (cross modifying code that's being executed in ring 0 is ... not > something CPU designers had in mind) >
Then, following your advice, kprobes should be re-designed to do a stop_machine around the int3 breakpoint insertion ? And gdb should be stopping all threads of a target process before inserting a breakpoint. Therefore, I do not seem to be the only one confused about Intel statement on this issue.
Mathieu
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