On 06/20/2019 07:31 PM, Sai Prakash Ranjan wrote:
Currently coresight etm and cpu-debug will go ahead with
the probe even when corresponding cpus are not available
and error out later in the probe path. In such cases, it
is better to abort the probe earlier.
Without this, setting *nosmp* will throw below errors:
[ 5.910622] coresight-cpu-debug 850000.debug: Coresight debug-CPU0 initialized
[ 5.914266] coresight-cpu-debug 852000.debug: CPU1 debug arch init failed
[ 5.921474] coresight-cpu-debug 854000.debug: CPU2 debug arch init failed
[ 5.928328] coresight-cpu-debug 856000.debug: CPU3 debug arch init failed
[ 5.935330] coresight etm0: CPU0: ETM v4.0 initialized
[ 5.941875] coresight-etm4x 85d000.etm: ETM arch init failed
[ 5.946794] coresight-etm4x: probe of 85d000.etm failed with error -22
[ 5.952707] coresight-etm4x 85e000.etm: ETM arch init failed
[ 5.958945] coresight-etm4x: probe of 85e000.etm failed with error -22
[ 5.964853] coresight-etm4x 85f000.etm: ETM arch init failed
[ 5.971096] coresight-etm4x: probe of 85f000.etm failed with error -22
That is expected. What else do you expect ?
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@xxxxxxxxxxxxxx>
---
drivers/hwtracing/coresight/coresight-platform.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c
index 8b03fa573684..3f4559596c6b 100644
--- a/drivers/hwtracing/coresight/coresight-platform.c
+++ b/drivers/hwtracing/coresight/coresight-platform.c
@@ -168,6 +168,9 @@ static int of_coresight_get_cpu(struct device *dev)
cpu = of_cpu_node_to_id(dn);
of_node_put(dn);
+ if (num_online_cpus() <= cpu)
+ return -ENODEV;
That is a pointless and terribly wrong check. What if you have only 2
online CPUs (CPU0 and CPU4) and you were processing the ETM for CPU4 ?
More over you should simply let the driver handle a case where the CPU
is not online. May be the driver could register a hotplug notifier and
bring itself up when the CPU comes online.
So, please drop this patch.
Kind regards
Suzuki
