linux-kernel - [tip:perf/urgent] perf/x86/intel: Add generic branch tracing check to intel_pmu_has

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Date:   Thu, 22 Nov 2018 02:13:58 -0800
From:   tip-bot for Jiri Olsa <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     acme@...hat.com, jolsa@...nel.org, stable@...r.kernel.org,
        a.p.zijlstra@...llo.nl, hpa@...or.com, peterz@...radead.org,
        eranian@...gle.com, acme@...nel.org, jolsa@...hat.com,
        vincent.weaver@...ne.edu, linux-kernel@...r.kernel.org,
        tglx@...utronix.de, alexander.shishkin@...ux.intel.com,
        torvalds@...ux-foundation.org, mingo@...nel.org
Subject: [tip:perf/urgent] perf/x86/intel: Add generic branch tracing check
 to intel_pmu_has_bts()

Commit-ID:  67266c1080ad56c31af72b9c18355fde8ccc124a
Gitweb:     https://git.kernel.org/tip/67266c1080ad56c31af72b9c18355fde8ccc124a
Author:     Jiri Olsa <jolsa@...nel.org>
AuthorDate: Wed, 21 Nov 2018 11:16:11 +0100
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Thu, 22 Nov 2018 09:45:09 +0100

perf/x86/intel: Add generic branch tracing check to intel_pmu_has_bts()

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 <jolsa@...nel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: <stable@...r.kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Stephane Eranian <eranian@...gle.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Vince Weaver <vincent.weaver@...ne.edu>
Link: http://lkml.kernel.org/r/20181121101612.16272-2-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@...nel.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 a95079abeb03..a15a73788693 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -2474,16 +2474,7 @@ done:
 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;
@@ -3105,10 +3096,8 @@ 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;
@@ -3170,7 +3159,7 @@ 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);