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authorJames Clark2022-05-11 15:45:58 +0100
committerSuzuki K Poulose2022-07-06 16:32:08 +0100
commit2d693ed436a67db06d1473c22d4caee899a4e9d2 (patch)
treec45eab26e0306d9bae1b3d8ea9f0e26944cfda90 /drivers/hwtracing
parentc06475910b526159adb02d82e7299e3151113285 (diff)
coresight: Add config flag to enable branch broadcast
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 <james.clark@arm.com> Reviewed-by: Mike Leach <mike.leach@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20220511144601.2257870-2-james.clark@arm.com
Diffstat (limited to 'drivers/hwtracing')
-rw-r--r--drivers/hwtracing/coresight/coresight-etm-perf.c2
-rw-r--r--drivers/hwtracing/coresight/coresight-etm4x-core.c14
2 files changed, 16 insertions, 0 deletions
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 87299e99dabb..cf249ecad5a5 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -696,6 +696,20 @@ 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) {
+ /*
+ * Missing BB support could cause silent decode errors
+ * so fail to open if it's not supported.
+ */
+ ret = -EINVAL;
+ goto out;
+ } else {
+ config->cfg |= BIT(ETM4_CFG_BIT_BB);
+ }
+ }
+
out:
return ret;
}