When enabled, all taken branch addresses are output, even if the branch
was because of a direct branch instruction. This enables reconstruction
of the program flow without having access to the memory image of the
code being executed.

Use bit 8 for the config option which would be the correct bit for
programming ETMv3. Although branch broadcast can't be enabled on ETMv3
because it's not in the define ETM3X_SUPPORTED_OPTIONS, using the
correct bit might help prevent future collisions or allow it to be
enabled if needed.

Signed-off-by: James Clark <redacted>
---
  drivers/hwtracing/coresight/coresight-etm-perf.c   | 2 ++
  drivers/hwtracing/coresight/coresight-etm4x-core.c | 9 +++++++++
  include/linux/coresight-pmu.h                      | 2 ++
  3 files changed, 13 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index c039b6ae206f..43bbd5dc3d3b 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c

@@ -52,6 +52,7 @@ static DEFINE_PER_CPU(struct coresight_device *, csdev_src);
   * The PMU formats were orignally for ETMv3.5/PTM's ETMCR 'config';
   * now take them as general formats and apply on all ETMs.
   */
+PMU_FORMAT_ATTR(branch_broadcast, "config:"__stringify(ETM_OPT_BRANCH_BROADCAST));
  PMU_FORMAT_ATTR(cycacc,		"config:" __stringify(ETM_OPT_CYCACC));
  /* contextid1 enables tracing CONTEXTIDR_EL1 for ETMv4 */
  PMU_FORMAT_ATTR(contextid1,	"config:" __stringify(ETM_OPT_CTXTID));

@@ -97,6 +98,7 @@ static struct attribute *etm_config_formats_attr[] = {
  	&format_attr_sinkid.attr,
  	&format_attr_preset.attr,
  	&format_attr_configid.attr,
+	&format_attr_branch_broadcast.attr,
  	NULL,
  };
  

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index bf18128cf5de..d2bafb50c66a 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c

@@ -692,6 +692,15 @@ static int etm4_parse_event_config(struct coresight_device *csdev,
  		ret = cscfg_csdev_enable_active_config(csdev, cfg_hash, preset);
  	}
  
+	/* branch broadcast - enable if selected and supported */
+	if (attr->config & BIT(ETM_OPT_BRANCH_BROADCAST)) {
+		if (!drvdata->trcbb) {
+			ret = -EINVAL;
+			goto out;
+		} else
+			config->cfg |= BIT(ETM4_CFG_BIT_BB);