perf/x86/intel: Support CPUID 10.ECX to disable fixed counters

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With Architectural Performance Monitoring Version 5, CPUID 10.ECX cpu
leaf indicates the fixed counter enumeration. This extends the previous
count to a bitmap which allows disabling even lower fixed counters.
It could be used by a Hypervisor.

The existing intel_ctrl variable is used to remember the bitmask of the
counters. All code that reads all counters is fixed to check this extra
bitmask.

Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Originally-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1611873611-156687-6-git-send-email-kan.liang@linux.intel.com

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Kan Liang 2021-01-28 14:40:11 -08:00 • committed by Peter Zijlstra

parent 61b985e3e7

commit 32451614da

3 changed files with 36 additions and 11 deletions

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8

arch/x86/events/core.c

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34

arch/x86/events/intel/core.c

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5

arch/x86/events/perf_event.h

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