linux-kernel - [PATCH 5/5] arm-cci: Fix CCI PMU event validation

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Date:	Tue, 10 Mar 2015 15:18:55 +0000
From:	"Suzuki K. Poulose" <suzuki.poulose@....com>
To:	linux-arm-kernel@...ts.infradead.org
Cc:	Nicolas Pitre <nico@...aro.org>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
	Kukjin Kim <kgene@...nel.org>,
	Abhilash Kesavan <a.kesavan@...sung.com>,
	Arnd Bergmann <arnd@...db.de>, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org, Liviu Dudau <liviu.dudau@....com>,
	Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
	Olof Johansson <olof@...om.net>,
	Pawel Moll <pawel.moll@....com>,
	Punit Agrawal <punit.agrawal@....com>,
	Sudeep Holla <sudeep.holla@....com>,
	Will Deacon <will.deacon@....com>,
	Catalin Marinas <catalin.marinas@....com>,
	"Suzuki K. Poulose" <suzuki.poulose@....com>
Subject: [PATCH 5/5] arm-cci: Fix CCI PMU event validation

From: "Suzuki K. Poulose" <suzuki.poulose@....com>

We mask the event with the CCI_PMU_EVENT_MASK, before passing
the config to pmu_validate_hw_event(), which causes extra bits
to be ignored and qualifies an invalid event code as valid.

e.g,
 $ perf stat -a -C 0 -e CCI_400/config=0x1ff,name=cycles/ sleep 1
   Performance counter stats for 'system wide':

         506951142      cycles

       1.013879626 seconds time elapsed

where, cycles has an event coding of 0xff. This patch also removes
the unnecessary 'event' mask in pmu_write_register, since the config_base
is set by the pmu code after the event is validated.

Changes since V2:
 - Switch to input unsigned long for pmu_validate_hw_event()

Signed-off-by: Suzuki K. Poulose <suzuki.poulose@....com>
---
 drivers/bus/arm-cci.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c
index 581190d..89c86e9 100644
--- a/drivers/bus/arm-cci.c
+++ b/drivers/bus/arm-cci.c
@@ -179,12 +179,15 @@ enum cci400_perf_events {
 #define CCI_REV_R1_MASTER_PORT_MIN_EV	0x00
 #define CCI_REV_R1_MASTER_PORT_MAX_EV	0x11
 
-static int pmu_validate_hw_event(u8 hw_event)
+static int pmu_validate_hw_event(unsigned long hw_event)
 {
 	u8 ev_source = CCI_PMU_EVENT_SOURCE(hw_event);
 	u8 ev_code = CCI_PMU_EVENT_CODE(hw_event);
 	int if_type;
 
+	if (hw_event & ~CCI_PMU_EVENT_MASK)
+		return -ENOENT;
+
 	switch (ev_source) {
 	case CCI_PORT_S0:
 	case CCI_PORT_S1:
@@ -258,7 +261,6 @@ static void pmu_enable_counter(int idx)
 
 static void pmu_set_event(int idx, unsigned long event)
 {
-	event &= CCI_PMU_EVENT_MASK;
 	pmu_write_register(event, idx, CCI_PMU_EVT_SEL);
 }
 
@@ -275,7 +277,7 @@ static int pmu_get_event_idx(struct cci_pmu_hw_events *hw, struct perf_event *ev
 {
 	struct cci_pmu *cci_pmu = to_cci_pmu(event->pmu);
 	struct hw_perf_event *hw_event = &event->hw;
-	unsigned long cci_event = hw_event->config_base & CCI_PMU_EVENT_MASK;
+	unsigned long cci_event = hw_event->config_base;
 	int idx;
 
 	if (cci_event == CCI_PMU_CYCLES) {
@@ -296,7 +298,7 @@ static int pmu_get_event_idx(struct cci_pmu_hw_events *hw, struct perf_event *ev
 static int pmu_map_event(struct perf_event *event)
 {
 	int mapping;
-	u8 config = event->attr.config & CCI_PMU_EVENT_MASK;
+	unsigned long config = event->attr.config;
 
 	if (event->attr.type < PERF_TYPE_MAX)
 		return -ENOENT;
-- 
1.7.9.5


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