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From: Anshuman Khandual <anshuman.khandual@arm.com>
To: linux-arm-kernel@lists.infradead.org, coresight@lists.linaro.org
Cc: mike.leach@linaro.org,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	linux-kernel@vger.kernel.org, mathieu.poirier@linaro.org,
	suzuki.poulose@arm.com
Subject: [RFC 09/11] coresight: etm-perf: Disable the path before capturing the trace data
Date: Tue, 10 Nov 2020 18:15:07 +0530	[thread overview]
Message-ID: <1605012309-24812-10-git-send-email-anshuman.khandual@arm.com> (raw)
In-Reply-To: <1605012309-24812-1-git-send-email-anshuman.khandual@arm.com>

perf handle structure needs to be shared with the TRBE IRQ handler for
capturing trace data and restarting the handle. There is a probability
of an undefined reference based crash when etm event is being stopped
while a TRBE IRQ also getting processed. This happens due the release
of perf handle via perf_aux_output_end(). This stops the sinks via the
link before releasing the handle, which will ensure that a simultaneous
TRBE IRQ could not happen.

Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
This might cause problem with traditional sink devices which can be
operated in both sysfs and perf mode. This needs to be addressed
correctly. One option would be to move the update_buffer callback
into the respective sink devices. e.g, disable().

 drivers/hwtracing/coresight/coresight-etm-perf.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index 534e205..1a37991 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -429,7 +429,9 @@ static void etm_event_stop(struct perf_event *event, int mode)
 
 		size = sink_ops(sink)->update_buffer(sink, handle,
 					      event_data->snk_config);
+		coresight_disable_path(path);
 		perf_aux_output_end(handle, size);
+		return;
 	}
 
 	/* Disabling the path make its elements available to other sessions */
-- 
2.7.4


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  parent reply	other threads:[~2020-11-10 12:47 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-10 12:44 [RFC 00/11] arm64: coresight: Enable ETE and TRBE Anshuman Khandual
2020-11-10 12:44 ` [RFC 01/11] arm64: Add TRBE definitions Anshuman Khandual
2020-11-10 12:45 ` [RFC 02/11] coresight: etm-perf: Allow an event to use different sinks Anshuman Khandual
2020-11-12  9:21   ` Suzuki K Poulose
2020-11-12 10:37     ` Linu Cherian
2020-11-12 11:09       ` Suzuki K Poulose
2020-11-10 12:45 ` [RFC 03/11] coresight: Do not scan for graph if none is present Anshuman Khandual
2020-11-10 12:45 ` [RFC 04/11] coresight: etm4x: Add support for PE OS lock Anshuman Khandual
2020-11-10 12:45 ` [RFC 05/11] coresight: ete: Add support for sysreg support Anshuman Khandual
2020-11-10 12:45 ` [RFC 06/11] coresight: ete: Detect ETE as one of the supported ETMs Anshuman Khandual
2020-11-14  5:36   ` Tingwei Zhang
2020-11-23  9:56     ` Suzuki K Poulose
2020-11-10 12:45 ` [RFC 07/11] coresight: sink: Add TRBE driver Anshuman Khandual
2020-11-12 10:13   ` Suzuki K Poulose
2020-11-25  5:25     ` Anshuman Khandual
2020-11-14  5:38   ` Tingwei Zhang
2020-11-23  3:51     ` Anshuman Khandual
2020-11-10 12:45 ` [RFC 08/11] coresight: etm-perf: Truncate the perf record if handle has no space Anshuman Khandual
2020-11-10 12:45 ` Anshuman Khandual [this message]
2020-11-12  9:27   ` [RFC 09/11] coresight: etm-perf: Disable the path before capturing the trace data Suzuki K Poulose
2020-11-23  6:08     ` Anshuman Khandual
2020-11-23 10:01       ` Suzuki K Poulose
2020-11-27 10:32   ` Suzuki K Poulose
2020-12-11 20:31     ` Mathieu Poirier
2020-12-14 10:00       ` Suzuki K Poulose
2020-11-10 12:45 ` [RFC 10/11] coresgith: etm-perf: Connect TRBE sink with ETE source Anshuman Khandual
2020-11-12  9:31   ` Suzuki K Poulose
2020-11-23  5:37     ` Anshuman Khandual
2020-12-11 21:31   ` Mathieu Poirier
2020-11-10 12:45 ` [RFC 11/11] dts: bindings: Document device tree binding for Arm TRBE Anshuman Khandual
2020-11-10 18:25 ` [RFC 00/11] arm64: coresight: Enable ETE and TRBE Mathieu Poirier
2020-11-14  5:17 ` Tingwei Zhang
2020-11-16 15:00   ` Mike Leach
2020-11-23  3:40     ` Anshuman Khandual
2020-11-23 12:30       ` Mike Leach
2020-11-23  2:43   ` Anshuman Khandual

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