coresight: etb10: Fix handling of perf mode

[ Upstream commit 987d1e8dcd370d96029a3d76a0031b043c4a69ae ]

If the ETB is already enabled in sysfs mode, the ETB reports
success even if a perf mode is requested. Fix this by checking
the requested mode.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
index 56ecd7aff5eb9542d70300d8bcfb153b8aa0b2da..d14a9cb7959a580f28cb1932e2cfdedfe1efa343 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-etb10.c
+++ b/drivers/hwtracing/coresight/coresight-etb10.c
@@ -155,6 +155,10 @@ static int etb_enable(struct coresight_device *csdev, u32 mode)
        if (val == CS_MODE_PERF)
                return -EBUSY;
 
+       /* Don't let perf disturb sysFS sessions */
+       if (val == CS_MODE_SYSFS && mode == CS_MODE_PERF)
+               return -EBUSY;
+
        /* Nothing to do, the tracer is already enabled. */
        if (val == CS_MODE_SYSFS)
                goto out;