[PATCH 3/4] perf cs_etm: Record ts_source in AUXTRACE_INFO for ETMv4 and ETE

From: German Gomez
Date: Wed May 04 2022 - 11:03:05 EST


Read the value of ts_source exposed by the driver and store it in the
ETMv4 and ETE header. If the interface doesn't exist (such as in older
Kernels), defaults to a safe value of -1.

Signed-off-by: German Gomez <german.gomez@xxxxxxx>
---
tools/perf/arch/arm/util/cs-etm.c | 46 +++++++++++++++++++++++++++++++
tools/perf/util/cs-etm.c | 2 ++
tools/perf/util/cs-etm.h | 2 ++
3 files changed, 50 insertions(+)

diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c
index 4899eb549b4d..f063fece90c3 100644
--- a/tools/perf/arch/arm/util/cs-etm.c
+++ b/tools/perf/arch/arm/util/cs-etm.c
@@ -53,6 +53,7 @@ static const char * const metadata_etmv4_ro[] = {
[CS_ETMV4_TRCIDR2] = "trcidr/trcidr2",
[CS_ETMV4_TRCIDR8] = "trcidr/trcidr8",
[CS_ETMV4_TRCAUTHSTATUS] = "mgmt/trcauthstatus",
+ [CS_ETMV4_TS_SOURCE] = "ts_source",
};

static const char * const metadata_ete_ro[] = {
@@ -62,6 +63,7 @@ static const char * const metadata_ete_ro[] = {
[CS_ETE_TRCIDR8] = "trcidr/trcidr8",
[CS_ETE_TRCAUTHSTATUS] = "mgmt/trcauthstatus",
[CS_ETE_TRCDEVARCH] = "mgmt/trcdevarch",
+ [CS_ETE_TS_SOURCE] = "ts_source",
};

static bool cs_etm_is_etmv4(struct auxtrace_record *itr, int cpu);
@@ -612,6 +614,32 @@ static int cs_etm_get_ro(struct perf_pmu *pmu, int cpu, const char *path)
return val;
}

+static int cs_etm_get_ro_signed(struct perf_pmu *pmu, int cpu, const char *path)
+{
+ char pmu_path[PATH_MAX];
+ int scan;
+ int val = 0;
+
+ /* Get RO metadata from sysfs */
+ snprintf(pmu_path, PATH_MAX, "cpu%d/%s", cpu, path);
+
+ scan = perf_pmu__scan_file(pmu, pmu_path, "%d", &val);
+ if (scan != 1)
+ pr_err("%s: error reading: %s\n", __func__, pmu_path);
+
+ return val;
+}
+
+static bool cs_etm_pmu_path_exists(struct perf_pmu *pmu, int cpu, const char *path)
+{
+ char pmu_path[PATH_MAX];
+
+ /* Get RO metadata from sysfs */
+ snprintf(pmu_path, PATH_MAX, "cpu%d/%s", cpu, path);
+
+ return perf_pmu__file_exists(pmu, pmu_path);
+}
+
#define TRCDEVARCH_ARCHPART_SHIFT 0
#define TRCDEVARCH_ARCHPART_MASK GENMASK(11, 0)
#define TRCDEVARCH_ARCHPART(x) (((x) & TRCDEVARCH_ARCHPART_MASK) >> TRCDEVARCH_ARCHPART_SHIFT)
@@ -653,6 +681,15 @@ static void cs_etm_save_etmv4_header(__u64 data[], struct auxtrace_record *itr,
metadata_etmv4_ro[CS_ETMV4_TRCIDR8]);
data[CS_ETMV4_TRCAUTHSTATUS] = cs_etm_get_ro(cs_etm_pmu, cpu,
metadata_etmv4_ro[CS_ETMV4_TRCAUTHSTATUS]);
+
+ /* Kernels older than 5.19 may not expose ts_source */
+ if (cs_etm_pmu_path_exists(cs_etm_pmu, cpu, metadata_etmv4_ro[CS_ETMV4_TS_SOURCE]))
+ data[CS_ETMV4_TS_SOURCE] = (__u64) cs_etm_get_ro_signed(cs_etm_pmu, cpu,
+ metadata_etmv4_ro[CS_ETMV4_TS_SOURCE]);
+ else {
+ pr_warning("[%03d] pmu file 'ts_source' not found. Fallback to safe value (-1)\n", cpu);
+ data[CS_ETMV4_TS_SOURCE] = (__u64) -1;
+ }
}

static void cs_etm_save_ete_header(__u64 data[], struct auxtrace_record *itr, int cpu)
@@ -678,6 +715,15 @@ static void cs_etm_save_ete_header(__u64 data[], struct auxtrace_record *itr, in
/* ETE uses the same registers as ETMv4 plus TRCDEVARCH */
data[CS_ETE_TRCDEVARCH] = cs_etm_get_ro(cs_etm_pmu, cpu,
metadata_ete_ro[CS_ETE_TRCDEVARCH]);
+
+ /* Kernels older than 5.19 may not expose ts_source */
+ if (cs_etm_pmu_path_exists(cs_etm_pmu, cpu, metadata_ete_ro[CS_ETE_TS_SOURCE]))
+ data[CS_ETE_TS_SOURCE] = (__u64) cs_etm_get_ro_signed(cs_etm_pmu, cpu,
+ metadata_ete_ro[CS_ETE_TS_SOURCE]);
+ else {
+ pr_warning("[%03d] pmu file 'ts_source' not found. Fallback to safe value (-1)\n", cpu);
+ data[CS_ETE_TS_SOURCE] = (__u64) -1;
+ }
}

static void cs_etm_get_metadata(int cpu, u32 *offset,
diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index 5991a1a46b5c..e883ef6d9c75 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -2537,6 +2537,7 @@ static const char * const cs_etmv4_priv_fmts[] = {
[CS_ETMV4_TRCIDR2] = " TRCIDR2 %llx\n",
[CS_ETMV4_TRCIDR8] = " TRCIDR8 %llx\n",
[CS_ETMV4_TRCAUTHSTATUS] = " TRCAUTHSTATUS %llx\n",
+ [CS_ETMV4_TS_SOURCE] = " TS_SOURCE %lld\n",
};

static const char * const cs_ete_priv_fmts[] = {
@@ -2551,6 +2552,7 @@ static const char * const cs_ete_priv_fmts[] = {
[CS_ETE_TRCIDR8] = " TRCIDR8 %llx\n",
[CS_ETE_TRCAUTHSTATUS] = " TRCAUTHSTATUS %llx\n",
[CS_ETE_TRCDEVARCH] = " TRCDEVARCH %llx\n",
+ [CS_ETE_TS_SOURCE] = " TS_SOURCE %lld\n",
};

static const char * const param_unk_fmt =
diff --git a/tools/perf/util/cs-etm.h b/tools/perf/util/cs-etm.h
index 817d068de98c..35b783178347 100644
--- a/tools/perf/util/cs-etm.h
+++ b/tools/perf/util/cs-etm.h
@@ -70,6 +70,7 @@ enum {
CS_ETMV4_TRCIDR2,
CS_ETMV4_TRCIDR8,
CS_ETMV4_TRCAUTHSTATUS,
+ CS_ETMV4_TS_SOURCE,
CS_ETMV4_PRIV_MAX,
};

@@ -91,6 +92,7 @@ enum {
CS_ETE_TRCIDR8,
CS_ETE_TRCAUTHSTATUS,
CS_ETE_TRCDEVARCH,
+ CS_ETE_TS_SOURCE,
CS_ETE_PRIV_MAX
};

--
2.25.1