[PATCH] coresight: etm4x: fix mis-usage of nr_resource in sysfs interface

Jonathan Zhou
2020-09-02T07:55:20Z

The member @nr_resource represents how many resource selector pairs,
and the pair 0 is always implemented and reserved.
So let's multiply by 2 when displaying the implemented resource seletors
and resetting the seletor configuration .
And also update the validation of the input @idx.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Shaokun Zhang <zhangshaokun@hisilicon.com>
Cc: lizixian@hisilicon.com
Signed-off-by: Jonathan Zhou <jonathan.zhouwen@huawei.com>
---
drivers/hwtracing/coresight/coresight-etm4x-sysfs.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
index b673e738bc9a..635b93d20efa 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
@@ -143,8 +143,10 @@ static ssize_t nr_resource_show(struct device *dev,
{
unsigned long val;
struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
-
- val = drvdata->nr_resource;
+ /* @nr_resource represents how many resource selector pairs,
+ * hence multiply by 2.
+ */
+ val = 2 * drvdata->nr_resource;
return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
}
static DEVICE_ATTR_RO(nr_resource);
@@ -236,7 +238,7 @@ static ssize_t reset_store(struct device *dev,
}

config->res_idx = 0x0;
- for (i = 0; i < drvdata->nr_resource; i++)
+ for (i = 2; i < 2 * drvdata->nr_resource; i++)
config->res_ctrl[i] = 0x0;

config->ss_idx = 0x0;
@@ -1663,8 +1665,11 @@ static ssize_t res_idx_store(struct device *dev,

if (kstrtoul(buf, 16, &val))
return -EINVAL;
- /* Resource selector pair 0 is always implemented and reserved */
- if ((val == 0) || (val >= drvdata->nr_resource))
+ /*
+ * Resource selector pair 0 is always implemented and reserved,
+ * namely an idx with 0 and 1 is illegal.
+ */
+ if ((val == 0) || (val == 1) || (val >= 2 * drvdata->nr_resource))
return -EINVAL;

/*
--
1.9.1