[PATCH v9 20/20] coresight: sysfs: Validate CPU online status for per-CPU sources

[Leo Yan]

The current SysFS flow first enables the links and sink, then rolls back
to disable them if the source fails to enable. This failure can occur if
the associated CPU is offline, which causes the SMP call to fail.

Validate whether the associated CPU is online for a per-CPU tracer.  If
the CPU is offline, return -ENODEV and bail out.

Tested-by: James Clark <james.clark at linaro.org>
Reviewed-by: Yeoreum Yun <yeoreum.yun at arm.com>
Reviewed-by: James Clark <james.clark at linaro.org>
Signed-off-by: Leo Yan <leo.yan at arm.com>
---
 drivers/hwtracing/coresight/coresight-sysfs.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c b/drivers/hwtracing/coresight/coresight-sysfs.c
index 75dd8c9f78174b7e604fbad6e8735656a2d643a0..b79c0abfeb77ed6f8fa299f083e0b6c656e0e6c1 100644
--- a/drivers/hwtracing/coresight/coresight-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-sysfs.c
@@ -184,6 +184,9 @@ static int coresight_validate_source_sysfs(struct coresight_device *csdev,
 		return -EINVAL;
 	}
 
+	if (coresight_is_percpu_source(csdev) && !cpu_online(csdev->cpu))
+		return -ENODEV;
+
 	return 0;
 }
 

-- 
2.34.1