[PATCH v1 3/4] coresight: tmc: hook panic callback for ETB/ETF
From: Leo Yan <hidden>
Date: 2017-06-03 14:43:43
Also in:
lkml
Subsystem:
arm/coresight framework and drivers, hardware tracing facilities, the rest · Maintainers:
Suzuki K Poulose, Alexander Shishkin, Linus Torvalds
The panic dump functionality has been ready, this patch is to hook panic callback function for ETB/ETF. Because the driver data structure has allocated buffer when the session started, so simply save ETB/ETF trace data into the buffer when panic happens. Below is simple usage when we connect kdump to extract trace data: - During kernel panic, tmc driver prints out below log. Dump ETB buffer 0x2000 at 0xffff80003bd5a180 - After get kernel dump file 'vmcore', use below command to extract ETB/ETF trace data. crash vmlinux vmcore rd 0xffff80003bd5a180 0x2000 -r cs_etb_trace.bin - Generate perf formatted file, so can be analyzed by perf tool: python perf_cs_dump_wrapper.py -i cs_etb_trace.bin -o perf.data ./perf script -v -F cpu,event,ip,sym,symoff --kallsyms ksymbol -i perf.data -k vmlinux Signed-off-by: Leo Yan <redacted> --- drivers/hwtracing/coresight/coresight-tmc-etf.c | 26 +++++++++++++++++++++++++ 1 file changed, 26 insertions(+)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
index e3b9fb8..4cadbb1 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c@@ -476,6 +476,31 @@ static void tmc_update_etf_buffer(struct coresight_device *csdev, CS_LOCK(drvdata->base); } +static int tmc_panic_cb(struct coresight_device *csdev) +{ + struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); + unsigned long flags; + + if (WARN_ON_ONCE(drvdata->config_type != TMC_CONFIG_TYPE_ETB && + drvdata->config_type != TMC_CONFIG_TYPE_ETF)) + return -EINVAL; + + spin_lock_irqsave(&drvdata->spinlock, flags); + + CS_UNLOCK(drvdata->base); + + tmc_flush_and_stop(drvdata); + tmc_etb_dump_hw(drvdata); + + CS_LOCK(drvdata->base); + + dev_err(drvdata->dev, "Dump ETB buffer 0x%x at 0x%p\n", + drvdata->len, drvdata->buf); + + spin_unlock_irqrestore(&drvdata->spinlock, flags); + return 0; +} + static const struct coresight_ops_sink tmc_etf_sink_ops = { .enable = tmc_enable_etf_sink, .disable = tmc_disable_etf_sink,
@@ -484,6 +509,7 @@ static const struct coresight_ops_sink tmc_etf_sink_ops = { .set_buffer = tmc_set_etf_buffer, .reset_buffer = tmc_reset_etf_buffer, .update_buffer = tmc_update_etf_buffer, + .panic_cb = tmc_panic_cb, }; static const struct coresight_ops_link tmc_etf_link_ops = {
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2.7.4