linux-kernel - [PATCH 09/14] coresight: etm4x: Improve usability of sysfs

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Date:   Mon,  4 Nov 2019 11:12:46 -0700
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     gregkh@...uxfoundation.org
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH 09/14] coresight: etm4x: Improve usability of sysfs - CID and VMID masks.

From: Mike Leach <mike.leach@...aro.org>

Context ID and VM ID masks required 2 value inputs, even when the
second value is ignored as insufficient CID / VMID comparators are
implemented.

Permit a single value to be used if that is sufficient to cover all
implemented comparators.

Signed-off-by: Mike Leach <mike.leach@...aro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
---
 drivers/hwtracing/coresight/coresight-etm4x-sysfs.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
index 8c056dd1a55e..1cfbddda0b4d 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
@@ -1794,6 +1794,7 @@ static ssize_t ctxid_masks_store(struct device *dev,
 	unsigned long val1, val2, mask;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
 	struct etmv4_config *config = &drvdata->config;
+	int nr_inputs;
 
 	/*
 	 * Don't use contextID tracing if coming from a PID namespace.  See
@@ -1809,7 +1810,9 @@ static ssize_t ctxid_masks_store(struct device *dev,
 	 */
 	if (!drvdata->ctxid_size || !drvdata->numcidc)
 		return -EINVAL;
-	if (sscanf(buf, "%lx %lx", &val1, &val2) != 2)
+	/* one mask if <= 4 comparators, two for up to 8 */
+	nr_inputs = sscanf(buf, "%lx %lx", &val1, &val2);
+	if ((drvdata->numcidc > 4) && (nr_inputs != 2))
 		return -EINVAL;
 
 	spin_lock(&drvdata->spinlock);
@@ -1983,6 +1986,7 @@ static ssize_t vmid_masks_store(struct device *dev,
 	unsigned long val1, val2, mask;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
 	struct etmv4_config *config = &drvdata->config;
+	int nr_inputs;
 
 	/*
 	 * only implemented when vmid tracing is enabled, i.e. at least one
@@ -1990,7 +1994,9 @@ static ssize_t vmid_masks_store(struct device *dev,
 	 */
 	if (!drvdata->vmid_size || !drvdata->numvmidc)
 		return -EINVAL;
-	if (sscanf(buf, "%lx %lx", &val1, &val2) != 2)
+	/* one mask if <= 4 comparators, two for up to 8 */
+	nr_inputs = sscanf(buf, "%lx %lx", &val1, &val2);
+	if ((drvdata->numvmidc > 4) && (nr_inputs != 2))
 		return -EINVAL;
 
 	spin_lock(&drvdata->spinlock);
-- 
2.17.1