coresight: etm4x: Add kernel configuration for CONTEXTID

Set the proper bit in the configuration register when contextID tracing
has been requested by user space.  That way PE_CONTEXT elements are
generated by the tracers when a process is installed on a CPU.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Tested-by: Leo Yan <leo.yan@linaro.org>
Tested-by: Robert Walker <robert.walker@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hwtracing/coresight/Kconfig

@@ -75,6 +75,7 @@ config CORESIGHT_SOURCE_ETM4X
 	bool "CoreSight Embedded Trace Macrocell 4.x driver"
 	depends on ARM64
 	select CORESIGHT_LINKS_AND_SINKS
+	select PID_IN_CONTEXTIDR
 	help
 	  This driver provides support for the ETM4.x tracer module, tracing the
 	  instructions that a processor is executing. This is primarily useful

drivers/hwtracing/coresight/coresight-etm-perf.c

@@ -29,6 +29,7 @@ static DEFINE_PER_CPU(struct coresight_device *, csdev_src);
 
 /* ETMv3.5/PTM's ETMCR is 'config' */
 PMU_FORMAT_ATTR(cycacc,		"config:" __stringify(ETM_OPT_CYCACC));
+PMU_FORMAT_ATTR(contextid,	"config:" __stringify(ETM_OPT_CTXTID));
 PMU_FORMAT_ATTR(timestamp,	"config:" __stringify(ETM_OPT_TS));
 PMU_FORMAT_ATTR(retstack,	"config:" __stringify(ETM_OPT_RETSTK));
 /* Sink ID - same for all ETMs */
@@ -36,6 +37,7 @@ PMU_FORMAT_ATTR(sinkid,		"config2:0-31");
 
 static struct attribute *etm_config_formats_attr[] = {
 	&format_attr_cycacc.attr,
+	&format_attr_contextid.attr,
 	&format_attr_timestamp.attr,
 	&format_attr_retstack.attr,
 	&format_attr_sinkid.attr,

drivers/hwtracing/coresight/coresight-etm4x.c

@@ -239,6 +239,11 @@ static int etm4_parse_event_config(struct etmv4_drvdata *drvdata,
 	if (attr->config & BIT(ETM_OPT_TS))
 		/* bit[11], Global timestamp tracing bit */
 		config->cfg |= BIT(11);
+
+	if (attr->config & BIT(ETM_OPT_CTXTID))
+		/* bit[6], Context ID tracing bit */
+		config->cfg |= BIT(ETM4_CFG_BIT_CTXTID);
+
 	/* return stack - enable if selected and supported */
 	if ((attr->config & BIT(ETM_OPT_RETSTK)) && drvdata->retstack)
 		/* bit[12], Return stack enable bit */

include/linux/coresight-pmu.h

@@ -12,11 +12,13 @@
 
 /* ETMv3.5/PTM's ETMCR config bit */
 #define ETM_OPT_CYCACC  12
+#define ETM_OPT_CTXTID	14
 #define ETM_OPT_TS      28
 #define ETM_OPT_RETSTK	29
 
 /* ETMv4 CONFIGR programming bits for the ETM OPTs */
 #define ETM4_CFG_BIT_CYCACC	4
+#define ETM4_CFG_BIT_CTXTID	6
 #define ETM4_CFG_BIT_TS		11
 #define ETM4_CFG_BIT_RETSTK	12
 

tools/include/linux/coresight-pmu.h

@@ -12,11 +12,13 @@
 
 /* ETMv3.5/PTM's ETMCR config bit */
 #define ETM_OPT_CYCACC  12
+#define ETM_OPT_CTXTID	14
 #define ETM_OPT_TS      28
 #define ETM_OPT_RETSTK	29
 
 /* ETMv4 CONFIGR programming bits for the ETM OPTs */
 #define ETM4_CFG_BIT_CYCACC	4
+#define ETM4_CFG_BIT_CTXTID	6
 #define ETM4_CFG_BIT_TS		11
 #define ETM4_CFG_BIT_RETSTK	12