From: Suzuki K Poulose <suzuki.poulose@arm.com>
Date: Thu, 20 Sep 2018 19:17:46 +0000 (-0600)
Subject: coresight: etb10: Fix handling of perf mode
X-Git-Tag: v4.18.19~183
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0cf50920c081a9771bc0b36119fe1defcbc543a9;p=thirdparty%2Fkernel%2Fstable.git

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 320d29df17e10..8c1d53f7af837 100644
--- a/drivers/hwtracing/coresight/coresight-etb10.c
+++ b/drivers/hwtracing/coresight/coresight-etb10.c
@@ -147,6 +147,10 @@ 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;