[PATCH v2 02/11] coresight: etm4x: Fix input validation for sysfs.

[Mike Leach]

A number of issues are fixed relating to sysfs input validation:-

1) bb_ctrl_store() - incorrect compare of bit select field to absolute
value. Reworked per ETMv4 specification.
2) seq_event_store() - incorrect mask value - register has two
event values.
3) cyc_threshold_store() - must mask with max before checking min
otherwise wrapped values can set illegal value below min.
4) res_ctrl_store() - update to mask off all res0 bits.

Reviewed-by: Leo Yan <leo....@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poir...@linaro.org>
Signed-off-by: Mike Leach <mike.le...@linaro.org>
---
 .../coresight/coresight-etm4x-sysfs.c         | 21 ++++++++++++-------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c 
b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
index b6984be0c515..cc8156318018 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
@@ -652,10 +652,13 @@ static ssize_t cyc_threshold_store(struct device *dev,
 
        if (kstrtoul(buf, 16, &val))
                return -EINVAL;
+
+       /* mask off max threshold before checking min value */
+       val &= ETM_CYC_THRESHOLD_MASK;
        if (val < drvdata->ccitmin)
                return -EINVAL;
 
-       config->ccctlr = val & ETM_CYC_THRESHOLD_MASK;
+       config->ccctlr = val;
        return size;
 }
 static DEVICE_ATTR_RW(cyc_threshold);
@@ -686,14 +689,16 @@ static ssize_t bb_ctrl_store(struct device *dev,
                return -EINVAL;
        if (!drvdata->nr_addr_cmp)
                return -EINVAL;
+
        /*
-        * Bit[7:0] selects which address range comparator is used for
-        * branch broadcast control.
+        * Bit[8] controls include(1) / exclude(0), bits[0-7] select
+        * individual range comparators. If include then at least 1
+        * range must be selected.
         */
-       if (BMVAL(val, 0, 7) > drvdata->nr_addr_cmp)
+       if ((val & BIT(8)) && (BMVAL(val, 0, 7) == 0))
                return -EINVAL;
 
-       config->bb_ctrl = val;
+       config->bb_ctrl = val & GENMASK(8, 0);
        return size;
 }
 static DEVICE_ATTR_RW(bb_ctrl);
@@ -1324,8 +1329,8 @@ static ssize_t seq_event_store(struct device *dev,
 
        spin_lock(&drvdata->spinlock);
        idx = config->seq_idx;
-       /* RST, bits[7:0] */
-       config->seq_ctrl[idx] = val & 0xFF;
+       /* Seq control has two masks B[15:8] F[7:0] */
+       config->seq_ctrl[idx] = val & 0xFFFF;
        spin_unlock(&drvdata->spinlock);
        return size;
 }
@@ -1580,7 +1585,7 @@ static ssize_t res_ctrl_store(struct device *dev,
        if (idx % 2 != 0)
                /* PAIRINV, bit[21] */
                val &= ~BIT(21);
-       config->res_ctrl[idx] = val;
+       config->res_ctrl[idx] = val & GENMASK(21, 0);
        spin_unlock(&drvdata->spinlock);
        return size;
 }
-- 
2.17.1