perf cs-etm: Configure timestamp generation in CPU-wide mode

When operating in CPU-wide mode tracers need to generate timestamps in
order to correlate the code being traced on one CPU with what is executed
on other CPUs.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Tested-by: Leo Yan <leo.yan@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20190524173508.29044-3-mathieu.poirier@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c
index 3912f0b..be1e4f2 100644 (file)
--- a/tools/perf/arch/arm/util/cs-etm.c
+++ b/tools/perf/arch/arm/util/cs-etm.c
@@ -99,6 +99,54 @@ out:
        return err;
 }
 
+static int cs_etm_set_timestamp(struct auxtrace_record *itr,
+                               struct perf_evsel *evsel, int cpu)
+{
+       struct cs_etm_recording *ptr;
+       struct perf_pmu *cs_etm_pmu;
+       char path[PATH_MAX];
+       int err = -EINVAL;
+       u32 val;
+
+       ptr = container_of(itr, struct cs_etm_recording, itr);
+       cs_etm_pmu = ptr->cs_etm_pmu;
+
+       if (!cs_etm_is_etmv4(itr, cpu))
+               goto out;
+
+       /* Get a handle on TRCIRD0 */
+       snprintf(path, PATH_MAX, "cpu%d/%s",
+                cpu, metadata_etmv4_ro[CS_ETMV4_TRCIDR0]);
+       err = perf_pmu__scan_file(cs_etm_pmu, path, "%x", &val);
+
+       /* There was a problem reading the file, bailing out */
+       if (err != 1) {
+               pr_err("%s: can't read file %s\n",
+                      CORESIGHT_ETM_PMU_NAME, path);
+               goto out;
+       }
+
+       /*
+        * TRCIDR0.TSSIZE, bit [28-24], indicates whether global timestamping
+        * is supported:
+        *  0b00000 Global timestamping is not implemented
+        *  0b00110 Implementation supports a maximum timestamp of 48bits.
+        *  0b01000 Implementation supports a maximum timestamp of 64bits.
+        */
+       val &= GENMASK(28, 24);
+       if (!val) {
+               err = -EINVAL;
+               goto out;
+       }
+
+       /* All good, let the kernel know */
+       evsel->attr.config |= (1 << ETM_OPT_TS);
+       err = 0;
+
+out:
+       return err;
+}
+
 static int cs_etm_set_option(struct auxtrace_record *itr,
                             struct perf_evsel *evsel, u32 option)
 {
@@ -118,6 +166,11 @@ static int cs_etm_set_option(struct auxtrace_record *itr,
                        if (err)
                                goto out;
                        break;
+               case ETM_OPT_TS:
+                       err = cs_etm_set_timestamp(itr, evsel, i);
+                       if (err)
+                               goto out;
+                       break;
                default:
                        goto out;
                }
@@ -343,6 +396,10 @@ static int cs_etm_recording_options(struct auxtrace_record *itr,
                err = cs_etm_set_option(itr, cs_etm_evsel, ETM_OPT_CTXTID);
                if (err)
                        goto out;
+
+               err = cs_etm_set_option(itr, cs_etm_evsel, ETM_OPT_TS);
+               if (err)
+                       goto out;
        }
 
        /* Add dummy event to keep tracking */