[tip:perf/core] perf_events: Check for filters on fixed counter events

tip-bot for Stephane Eranian
2009-10-09T14:23:16Z

Commit-ID: 04a705df47d1ea27ca2b066f24b1951c51792d0d
Gitweb: http://git.kernel.org/tip/04a705df47d1ea27ca2b066f24b1951c51792d0d
Author: Stephane Eranian <eranian@googlemail.com>
AuthorDate: Tue, 6 Oct 2009 16:42:08 +0200
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 9 Oct 2009 15:56:10 +0200

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>
---
arch/x86/include/asm/perf_event.h | 13 ++++++++++++-
arch/x86/kernel/cpu/perf_event.c | 6 ++++++
2 files changed, 18 insertions(+), 1 deletions(-)

diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index ad7ce3f..8d9f854 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -28,9 +28,20 @@
*/
#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
+#define ARCH_PERFMON_UNHALTED_CORE_CYCLES_INDEX 0
#define ARCH_PERFMON_UNHALTED_CORE_CYCLES_PRESENT \
(1 << (ARCH_PERFMON_UNHALTED_CORE_CYCLES_INDEX))

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index b5801c3..1d16bd6 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -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)))