[PATCH v3 5/8] perf cs-etm: Support PID tracing in config

Leo Yan
2021-02-06T15:10:34Z

From: Suzuki K Poulose <suzuki.poulose@arm.com>

If the kernel is running at EL2, the pid of a task is exposed via VMID
instead of the CONTEXTID. Add support for this in the perf tool.

This patch respects user setting if user has specified any configs
from "contextid", "contextid1" or "contextid2"; otherwise, it
dynamically sets config based on PMU format "contextid".

Cc: Mike Leach <mike.leach@linaro.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Al Grant <al.grant@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Co-developed-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
---
tools/include/linux/coresight-pmu.h | 3 ++
tools/perf/arch/arm/util/cs-etm.c | 61 +++++++++++++++++++++++------
2 files changed, 52 insertions(+), 12 deletions(-)

diff --git a/tools/include/linux/coresight-pmu.h b/tools/include/linux/coresight-pmu.h
index 5dc47cfdcf07..4ac5c081af93 100644
--- a/tools/include/linux/coresight-pmu.h
+++ b/tools/include/linux/coresight-pmu.h
@@ -20,14 +20,17 @@
*/
#define ETM_OPT_CYCACC 12
#define ETM_OPT_CTXTID 14
+#define ETM_OPT_CTXTID2 15
#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_VMID 7
#define ETM4_CFG_BIT_TS 11
#define ETM4_CFG_BIT_RETSTK 12
+#define ETM4_CFG_BIT_VMID_OPT 15

static inline int coresight_get_trace_id(int cpu)
{
diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c
index c25c878fd06c..fa6f91a7c8a1 100644
--- a/tools/perf/arch/arm/util/cs-etm.c
+++ b/tools/perf/arch/arm/util/cs-etm.c
@@ -67,6 +67,7 @@ static int cs_etm_set_context_id(struct auxtrace_record *itr,
char path[PATH_MAX];
int err = -EINVAL;
u32 val;
+ u64 contextid;

ptr = container_of(itr, struct cs_etm_recording, itr);
cs_etm_pmu = ptr->cs_etm_pmu;
@@ -86,25 +87,59 @@ static int cs_etm_set_context_id(struct auxtrace_record *itr,
goto out;
}

+ /* User has configured for PID tracing, respects it. */
+ contextid = evsel->core.attr.config &
+ (BIT(ETM_OPT_CTXTID) | BIT(ETM_OPT_CTXTID2));
+
/*
- * TRCIDR2.CIDSIZE, bit [9-5], indicates whether contextID tracing
- * is supported:
- * 0b00000 Context ID tracing is not supported.
- * 0b00100 Maximum of 32-bit Context ID size.
- * All other values are reserved.
+ * If user doesn't configure the contextid format, parse PMU format and
+ * enable PID tracing according to the "contextid" format bits:
+ *
+ * If bit ETM_OPT_CTXTID is set, trace CONTEXTIDR_EL1;
+ * If bit ETM_OPT_CTXTID2 is set, trace CONTEXTIDR_EL2.
*/
- val = BMVAL(val, 5, 9);
- if (!val || val != 0x4) {
- err = -EINVAL;
- goto out;
+ if (!contextid)
+ contextid = perf_pmu__format_bits(&cs_etm_pmu->format,
+ "contextid");
+
+ if (contextid & BIT(ETM_OPT_CTXTID)) {
+ /*
+ * TRCIDR2.CIDSIZE, bit [9-5], indicates whether contextID
+ * tracing is supported:
+ * 0b00000 Context ID tracing is not supported.
+ * 0b00100 Maximum of 32-bit Context ID size.
+ * All other values are reserved.
+ */
+ val = BMVAL(val, 5, 9);
+ if (!val || val != 0x4) {
+ pr_err("%s: CONTEXTIDR_EL1 isn't supported\n",
+ CORESIGHT_ETM_PMU_NAME);
+ err = -EINVAL;
+ goto out;
+ }
+ }
+
+ if (contextid & BIT(ETM_OPT_CTXTID2)) {
+ /*
+ * TRCIDR2.VMIDOPT[30:29] != 0 and
+ * TRCIDR2.VMIDSIZE[14:10] == 0b00100 (32bit virtual contextid)
+ * We can't support CONTEXTIDR in VMID if the size of the
+ * virtual context id is < 32bit.
+ * Any value of VMIDSIZE >= 4 (i.e, > 32bit) is fine for us.
+ */
+ if (!BMVAL(val, 29, 30) || BMVAL(val, 10, 14) < 4) {
+ pr_err("%s: CONTEXTIDR_EL2 isn't supported\n",
+ CORESIGHT_ETM_PMU_NAME);
+ err = -EINVAL;
+ goto out;
+ }
}

/* All good, let the kernel know */
- evsel->core.attr.config |= (1 << ETM_OPT_CTXTID);
+ evsel->core.attr.config |= contextid;
err = 0;

out:
-
return err;
}

@@ -489,7 +524,9 @@ static u64 cs_etmv4_get_config(struct auxtrace_record *itr)
config |= BIT(ETM4_CFG_BIT_TS);
if (config_opts & BIT(ETM_OPT_RETSTK))
config |= BIT(ETM4_CFG_BIT_RETSTK);
-
+ if (config_opts & BIT(ETM_OPT_CTXTID2))
+ config |= BIT(ETM4_CFG_BIT_VMID) |
+ BIT(ETM4_CFG_BIT_VMID_OPT);
return config;
}

--
2.25.1