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Commit 04a705df authored Oct 06, 2009 by Stephane Eranian Committed by Ingo Molnar Oct 09, 2009

perf_events: Check for filters on fixed counter events



Intel fixed counters do not support all the filters possible with a
generic counter. Thus, if a fixed counter event is passed but with
certain filters set, then the fixed_mode_idx() function must fail
and the event must be measured in a generic counter instead.

Reject filters are: inv, edge, cnt-mask.

Signed-off-by: Stephane Eranian <eranian@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1254840129-6198-2-git-send-email-eranian@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 26dd2cb0

arch/x86/include/asm/perf_event.h

+12 −1

Original line number	Diff line number	Diff line
		@@ -28,6 +28,17 @@
		*/
		#define ARCH_PERFMON_EVENT_MASK 0xffff

		/*
		* filter mask to validate fixed counter events.
		* the following filters disqualify for fixed counters:
		* - inv
		* - edge
		* - cnt-mask
		* The other filters are supported by fixed counters.
		* The any-thread option is supported starting with v3.
		*/
		#define ARCH_PERFMON_EVENT_FILTER_MASK 0xff840000

		#define ARCH_PERFMON_UNHALTED_CORE_CYCLES_SEL 0x3c
		#define ARCH_PERFMON_UNHALTED_CORE_CYCLES_UMASK (0x00 << 8)
		#define ARCH_PERFMON_UNHALTED_CORE_CYCLES_INDEX 0

arch/x86/kernel/cpu/perf_event.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -1349,6 +1349,12 @@ fixed_mode_idx(struct perf_event event, struct hw_perf_event hwc)
		if (!x86_pmu.num_events_fixed)
		return -1;

		/*
		* fixed counters do not take all possible filters
		*/
		if (hwc->config & ARCH_PERFMON_EVENT_FILTER_MASK)
		return -1;

		if (unlikely(hw_event == x86_pmu.event_map(PERF_COUNT_HW_INSTRUCTIONS)))
		return X86_PMC_IDX_FIXED_INSTRUCTIONS;
		if (unlikely(hw_event == x86_pmu.event_map(PERF_COUNT_HW_CPU_CYCLES)))