On 22 November 2017 at 12:09, Mathieu Poirier mathieu.poirier@linaro.org wrote:
On Tue, Nov 21, 2017 at 11:08:44AM +0800, Leo Yan wrote:
We need to dump etmv4 info as metadata, so the data can be used for offline checking for configuration and generate 'perf' compatible file. This commit hooks etmv4 callback for panic dump.
Signed-off-by: Leo Yan leo.yan@linaro.org
drivers/hwtracing/coresight/coresight-etm4x.c | 22 ++++++++++++++++++++++ drivers/hwtracing/coresight/coresight-etm4x.h | 15 +++++++++++++++ 2 files changed, 37 insertions(+)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c index cf364a5..bf9608b 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x.c +++ b/drivers/hwtracing/coresight/coresight-etm4x.c @@ -418,11 +418,33 @@ static void etm4_disable(struct coresight_device *csdev, local_set(&drvdata->mode, CS_MODE_DISABLED); }
+static void etm4_panic_cb(void *data) +{
struct coresight_device *csdev = (struct coresight_device *)data;int cpu = smp_processor_id();struct etmv4_drvdata *drvdata = etmdrvdata[cpu];struct etmv4_config *config = &drvdata->config;struct etmv4_metadata *metadata = &drvdata->metadata;metadata->magic = ETM4_METADATA_MAGIC;metadata->cpu = cpu;metadata->trcconfigr = config->cfg;metadata->trctraceidr = drvdata->trcid;metadata->trcidr0 = readl_relaxed(drvdata->base + TRCIDR0);metadata->trcidr1 = readl_relaxed(drvdata->base + TRCIDR1);metadata->trcidr2 = readl_relaxed(drvdata->base + TRCIDR2);metadata->trcidr8 = readl_relaxed(drvdata->base + TRCIDR8);I'm pretty sure this won't work on all architecture. This tracer may not be powered when this is called and depending on the power domain the TRCIDRx registers are in it may lock.
Simply read those at boot time as part of the _probe() function.
Thinking about this will work when operating from sysFS but theoretically inaccurate from perf. Say we have a 4 CPU system where for a perf session only 2 CPUs were used for trace acquisition - the process was simply not scheduled on the other 2 CPU. With the above code 2 CPUs (the ones that were actually used) will have the right configuration while the other two will have the default tracer configuration (since etm4_parse_event_config() was never called on them).
Values in TRCIDR{0, 1, 2, 8} and TRCAUTHSTATUS is RO and won't change. So those can be filled at _probe() time when tracers are instantiated. Values for trcconfigr ang trctraceidr are trickier.
When operating from sysFS tracer configuration should be recorded in etm4_enable_sysfs(), probably just before smp_call_function_single(). When operating from perf adding all tracers to the dump list should be done in etm_setup_aux() and an update for the configuration in etm4_enable_perf(), just before etm4_enable_hw(). When circling through tracers to communicate the metadata to the kdump mechanic check if buf != NULL, what way we only communicate information about tracers that were used.
Removal of the tracers from the dump list should be done in etm_free_aux()
This will need testing :o)
Mathieu
metadata->trcauthstatus = readl_relaxed(drvdata->base + TRCAUTHSTATUS);coresight_dump_update(csdev, (char *)metadata, sizeof(*metadata));+}
static const struct coresight_ops_source etm4_source_ops = { .cpu_id = etm4_cpu_id, .trace_id = etm4_trace_id, .enable = etm4_enable, .disable = etm4_disable,
.panic_cb = etm4_panic_cb,};
static const struct coresight_ops etm4_cs_ops = { diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h index b3b5ea7..08dc8b7 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x.h +++ b/drivers/hwtracing/coresight/coresight-etm4x.h @@ -198,6 +198,20 @@ #define ETM_EXLEVEL_NS_HYP BIT(14) #define ETM_EXLEVEL_NS_NA BIT(15)
+#define ETM4_METADATA_MAGIC 0x4040404040404040ULL
+struct etmv4_metadata {
u64 magic;u64 cpu;u64 trcconfigr;u64 trctraceidr;u64 trcidr0;u64 trcidr1;u64 trcidr2;u64 trcidr8;u64 trcauthstatus;+};
/**
- struct etmv4_config - configuration information related to an ETMv4
- @mode: Controls various modes supported by this ETM.
@@ -393,6 +407,7 @@ struct etmv4_drvdata { bool atbtrig; bool lpoverride; struct etmv4_config config;
struct etmv4_metadata metadata;};
/* Address comparator access types */
2.7.4