From 987d1e8dcd370d96029a3d76a0031b043c4a69ae Mon Sep 17 00:00:00 2001
From: Suzuki K Poulose <suzuki.poulose@arm.com>
Date: Thu, 20 Sep 2018 13:17:46 -0600
Subject: [PATCH] coresight: etb10: Fix handling of perf mode
Git-commit: 987d1e8dcd370d96029a3d76a0031b043c4a69ae
Patch-mainline: v4.20-rc1
References: bsc#1051510
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>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/hwtracing/coresight/coresight-etb10.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
index 306119eaf16a..0dad8626bcfb 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;
--
2.16.4