From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
The PEBS 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.
"""
Since we had problems with this earlier, don't allow cmask, any, edge, invert
as raw events, except for the ones explicitly listed as pebs_aliases.
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/perf_event.h | 2 +-
arch/x86/kernel/cpu/perf_event_intel.c | 24 ++++++++++++++++++++----
2 files changed, 21 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h
index 7f5c75c..e46f932 100644
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -386,7 +386,7 @@ struct x86_pmu {
int pebs_record_size;
void (*drain_pebs)(struct pt_regs *regs);
struct event_constraint *pebs_constraints;
- void (*pebs_aliases)(struct perf_event *event);
+ bool (*pebs_aliases)(struct perf_event *event);
int max_pebs_events;
/*
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index cc45deb..126c971 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -1447,7 +1447,7 @@ static void intel_put_event_constraints(struct cpu_hw_events *cpuc,
intel_put_shared_regs_event_constraints(cpuc, event);
}
-static void intel_pebs_aliases_core2(struct perf_event *event)
+static bool intel_pebs_aliases_core2(struct perf_event *event)
{
if ((event->hw.config & X86_RAW_EVENT_MASK) == 0x003c) {
/*
@@ -1472,10 +1472,12 @@ static void intel_pebs_aliases_core2(struct perf_event *event)
alt_config |= (event->hw.config & ~X86_RAW_EVENT_MASK);
event->hw.config = alt_config;
+ return true;
}
+ return false;
}
-static void intel_pebs_aliases_snb(struct perf_event *event)
+static bool intel_pebs_aliases_snb(struct perf_event *event)
{
if ((event->hw.config & X86_RAW_EVENT_MASK) == 0x003c) {
/*
@@ -1500,7 +1502,9 @@ static void intel_pebs_aliases_snb(struct perf_event *event)
alt_config |= (event->hw.config & ~X86_RAW_EVENT_MASK);
event->hw.config = alt_config;
+ return true;
}
+ return false;
}
static int intel_pmu_hw_config(struct perf_event *event)
@@ -1510,8 +1514,20 @@ static int intel_pmu_hw_config(struct perf_event *event)
if (ret)
return ret;
- if (event->attr.precise_ip && x86_pmu.pebs_aliases)
- x86_pmu.pebs_aliases(event);
+ if (event->attr.precise_ip) {
+ /*
+ * Don't allow unusal flags with PEBS, as that
+ * may confuse the CPU.
+ *
+ * The only exception are explicitely listed pebs_aliases
+ */
+ if ((!x86_pmu.pebs_aliases || !x86_pmu.pebs_aliases(event)) &&
+ (event->attr.config & (ARCH_PERFMON_EVENTSEL_CMASK|
+ ARCH_PERFMON_EVENTSEL_EDGE|
+ ARCH_PERFMON_EVENTSEL_INV|
+ ARCH_PERFMON_EVENTSEL_ANY)))
+ return -EIO;
+ }
if (intel_pmu_needs_lbr_smpl(event)) {
ret = intel_pmu_setup_lbr_filter(event);
--
1.7.7.6
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