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

From: Suzuki K. Poulose
Date: Tue Mar 10 2015 - 11:19:18 EST


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

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@xxxxxxx>
---
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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