Messages in this thread | | | Date | Tue, 7 May 2013 13:04:15 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH 2/2] perf, x86: Don't allow unusual PEBS raw flags |
| |
* Peter Zijlstra <peterz@infradead.org> wrote:
> On Tue, May 07, 2013 at 08:48:05AM +0200, Ingo Molnar wrote: > > Also, this code only runs when the event is set up, so a bit of sanity > > checking can only help, right? > > Nah, its all very circumspect. In fact; while what Andi states is 'true': > > > documentation in the Intel SDM 18.6.1.1 states: > > > > """ > > PEBS events are only valid when the following fields of IA32_PERFEVTSELx are all > > zero: AnyThread, Edge, Invert, CMask. > > """ > > It is also true that Intel themselves gave us events that contradict this; look > at the intel_pebs_aliases*() functions. > > This patch would make it impossible to manually create those events.
I missed that bit of obfuscation ...
> Further, there's something entirely different behind this.
Ok, I agree with you, this needs to be fully explained.
Thanks,
Ingo
| |