[PATCH 2/3] perf/x86/intel: Add generic branch tracing check to intel_pmu_has_bts

[Jiri Olsa]

Currently we check the branch tracing only by checking for the
PERF_COUNT_HW_BRANCH_INSTRUCTIONS event of PERF_TYPE_HARDWARE
type. But we can define the same event with the PERF_TYPE_RAW
type.

Changing the intel_pmu_has_bts code to check on event's final
hw config value, so both HW types are covered.

Adding unlikely to intel_pmu_has_bts condition calls, because
it was used in the original code in intel_bts_constraints.

Signed-off-by: Jiri Olsa <jo...@kernel.org>
---
 arch/x86/events/intel/core.c | 17 +++--------------
 arch/x86/events/perf_event.h | 13 +++++++++----
 2 files changed, 12 insertions(+), 18 deletions(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 8c1efb4d8f47..3fd3842571e8 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -2470,16 +2470,7 @@ static int intel_pmu_handle_irq(struct pt_regs *regs)
 static struct event_constraint *
 intel_bts_constraints(struct perf_event *event)
 {
-       struct hw_perf_event *hwc = &event->hw;
-       unsigned int hw_event, bts_event;
-
-       if (event->attr.freq)
-               return NULL;
-
-       hw_event = hwc->config & INTEL_ARCH_EVENT_MASK;
-       bts_event = x86_pmu.event_map(PERF_COUNT_HW_BRANCH_INSTRUCTIONS);
-
-       if (unlikely(hw_event == bts_event && hwc->sample_period == 1))
+       if (unlikely(intel_pmu_has_bts(event)))
                return &bts_constraint;
 
        return NULL;
@@ -3101,10 +3092,8 @@ static unsigned long intel_pmu_large_pebs_flags(struct 
perf_event *event)
 static int intel_pmu_bts_config(struct perf_event *event)
 {
        struct perf_event_attr *attr = &event->attr;
-       struct hw_perf_event *hwc = &event->hw;
 
-       if (attr->config == PERF_COUNT_HW_BRANCH_INSTRUCTIONS &&
-           !attr->freq && hwc->sample_period == 1) {
+       if (unlikely(intel_pmu_has_bts(event))) {
                /* BTS is not supported by this architecture. */
                if (!x86_pmu.bts_active)
                        return -EOPNOTSUPP;
@@ -3166,7 +3155,7 @@ static int intel_pmu_hw_config(struct perf_event *event)
                /*
                 * BTS is set up earlier in this path, so don't account twice
                 */
-               if (!intel_pmu_has_bts(event)) {
+               if (!unlikely(intel_pmu_has_bts(event))) {
                        /* disallow lbr if conflicting events are present */
                        if (x86_add_exclusive(x86_lbr_exclusive_lbr))
                                return -EBUSY;
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index adae087cecdd..78d7b7031bfc 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -859,11 +859,16 @@ static inline int amd_pmu_init(void)
 
 static inline bool intel_pmu_has_bts(struct perf_event *event)
 {
-       if (event->attr.config == PERF_COUNT_HW_BRANCH_INSTRUCTIONS &&
-           !event->attr.freq && event->hw.sample_period == 1)
-               return true;
+       struct hw_perf_event *hwc = &event->hw;
+       unsigned int hw_event, bts_event;
+
+       if (event->attr.freq)
+               return false;
+
+       hw_event = hwc->config & INTEL_ARCH_EVENT_MASK;
+       bts_event = x86_pmu.event_map(PERF_COUNT_HW_BRANCH_INSTRUCTIONS);
 
-       return false;
+       return hw_event == bts_event && hwc->sample_period == 1;
 }
 
 int intel_pmu_save_and_restart(struct perf_event *event);
-- 
2.17.2