linux-kernel - [PATCH] perf/x86/intel/uncore: Handle invalid event coding for free-running counter

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Message-Id: <1554994458-110235-1-git-send-email-kan.liang@linux.intel.com>
Date:   Thu, 11 Apr 2019 07:54:18 -0700
From:   kan.liang@...ux.intel.com
To:     peterz@...radead.org, tglx@...utronix.de, mingo@...hat.com,
        linux-kernel@...r.kernel.org
Cc:     acme@...nel.org, eranian@...gle.com, ak@...ux.intel.com,
        Kan Liang <kan.liang@...ux.intel.com>, stable@...r.kernel.org
Subject: [PATCH] perf/x86/intel/uncore: Handle invalid event coding for free-running counter

From: Kan Liang <kan.liang@...ux.intel.com>

Counting with invalid event coding for free-running counter may cause
OOPs, e.g. uncore_iio_free_running_0/event=1/.

Current code only validate the event with free-running event format,
event=0xff,umask=0xXY. Non-free-running event format never be checked
for the PMU with free-running counters.

Add generic hw_config() to check and reject the invalid event coding
for free-running PMU.

Fixes: 0f519f0352e3 ("perf/x86/intel/uncore: Support IIO free-running counters on SKX")
Signed-off-by: Kan Liang <kan.liang@...ux.intel.com>
Cc: stable@...r.kernel.org
---
 arch/x86/events/intel/uncore.h       | 10 ++++++++++
 arch/x86/events/intel/uncore_snbep.c |  1 +
 2 files changed, 11 insertions(+)

diff --git a/arch/x86/events/intel/uncore.h b/arch/x86/events/intel/uncore.h
index 79eb2e2..28499e3 100644
--- a/arch/x86/events/intel/uncore.h
+++ b/arch/x86/events/intel/uncore.h
@@ -419,6 +419,16 @@ static inline bool is_freerunning_event(struct perf_event *event)
 	       (((cfg >> 8) & 0xff) >= UNCORE_FREERUNNING_UMASK_START);
 }
 
+/* Check and reject invalid config */
+static inline int uncore_freerunning_hw_config(struct intel_uncore_box *box,
+					       struct perf_event *event)
+{
+	if (is_freerunning_event(event))
+		return 0;
+
+	return -EINVAL;
+}
+
 static inline void uncore_disable_box(struct intel_uncore_box *box)
 {
 	if (box->pmu->type->ops->disable_box)
diff --git a/arch/x86/events/intel/uncore_snbep.c b/arch/x86/events/intel/uncore_snbep.c
index b10e043..8e4e8e4 100644
--- a/arch/x86/events/intel/uncore_snbep.c
+++ b/arch/x86/events/intel/uncore_snbep.c
@@ -3585,6 +3585,7 @@ static struct uncore_event_desc skx_uncore_iio_freerunning_events[] = {
 
 static struct intel_uncore_ops skx_uncore_iio_freerunning_ops = {
 	.read_counter		= uncore_msr_read_counter,
+	.hw_config		= uncore_freerunning_hw_config,
 };
 
 static struct attribute *skx_uncore_iio_freerunning_formats_attr[] = {
-- 
2.7.4