Messages in this thread | | | Date | Mon, 20 Oct 2014 11:24:13 +0200 | From | Martin Schwidefsky <> | Subject | Re: [RFC 5/5] x86,perf: Only allow rdpmc if a perf_event is mapped |
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On Mon, 20 Oct 2014 10:48:13 +0200 Peter Zijlstra <peterz@infradead.org> wrote:
> > - cpumsf_pmu_event_idx is the same as power_pmu_event_idx. > > Oh cute, lets ask the s390 people, do you guys have a userspace > instruction to read the actual counter value?
The "extract cpu counter" ECCTR instruction can be authorized to be used in user-space with a bit in CR0. With the current code this bit is not set, the cpu measurement facility is not usable in user space without a patch to the kernel.
-- blue skies, Martin.
"Reality continues to ruin my life." - Calvin.
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