perf cs-etm: Handle PERF_RECORD_AUX_OUTPUT_HW_ID packet
authorMike Leach <mike.leach@linaro.org>
Fri, 31 Mar 2023 05:56:45 +0000 (06:56 +0100)
committerArnaldo Carvalho de Melo <acme@redhat.com>
Tue, 4 Apr 2023 12:39:57 +0000 (09:39 -0300)
When using dynamically assigned CoreSight trace IDs the drivers can output
the ID / CPU association as a PERF_RECORD_AUX_OUTPUT_HW_ID packet.

Update cs-etm decoder to handle this packet by setting the CPU/Trace ID
mapping.

Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Mike Leach <mike.leach@linaro.org>
Acked-by: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Darren Hart <darren@os.amperecomputing.com>
Cc: Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230331055645.26918-2-mike.leach@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
tools/include/linux/coresight-pmu.h
tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
tools/perf/util/cs-etm.c

index 1760f9a..cef3b1c 100644 (file)
@@ -31,6 +31,9 @@
  */
 #define CORESIGHT_TRACE_ID_UNUSED_FLAG BIT(31)
 
+/* Value to set for unused trace ID values */
+#define CORESIGHT_TRACE_ID_UNUSED_VAL  0x7F
+
 /*
  * Below are the definition of bit offsets for perf option, and works as
  * arbitrary values for all ETM versions.
 #define ETM4_CFG_BIT_RETSTK    12
 #define ETM4_CFG_BIT_VMID_OPT  15
 
+/*
+ * Interpretation of the PERF_RECORD_AUX_OUTPUT_HW_ID payload.
+ * Used to associate a CPU with the CoreSight Trace ID.
+ * [07:00] - Trace ID - uses 8 bits to make value easy to read in file.
+ * [59:08] - Unused (SBZ)
+ * [63:60] - Version
+ */
+#define CS_AUX_HW_ID_TRACE_ID_MASK     GENMASK_ULL(7, 0)
+#define CS_AUX_HW_ID_VERSION_MASK      GENMASK_ULL(63, 60)
+
+#define CS_AUX_HW_ID_CURR_VERSION 0
+
 #endif
index d0e521d..82a27ab 100644 (file)
@@ -668,6 +668,7 @@ cs_etm_decoder__create_etm_decoder(struct cs_etm_decoder_params *d_params,
        switch (t_params->protocol) {
        case CS_ETM_PROTO_ETMV3:
        case CS_ETM_PROTO_PTM:
+               csid = (t_params->etmv3.reg_idr & CORESIGHT_TRACE_ID_VAL_MASK);
                cs_etm_decoder__gen_etmv3_config(t_params, &config_etmv3);
                decoder->decoder_name = (t_params->protocol == CS_ETM_PROTO_ETMV3) ?
                                                        OCSD_BUILTIN_DCD_ETMV3 :
@@ -675,11 +676,13 @@ cs_etm_decoder__create_etm_decoder(struct cs_etm_decoder_params *d_params,
                trace_config = &config_etmv3;
                break;
        case CS_ETM_PROTO_ETMV4i:
+               csid = (t_params->etmv4.reg_traceidr & CORESIGHT_TRACE_ID_VAL_MASK);
                cs_etm_decoder__gen_etmv4_config(t_params, &trace_config_etmv4);
                decoder->decoder_name = OCSD_BUILTIN_DCD_ETMV4I;
                trace_config = &trace_config_etmv4;
                break;
        case CS_ETM_PROTO_ETE:
+               csid = (t_params->ete.reg_traceidr & CORESIGHT_TRACE_ID_VAL_MASK);
                cs_etm_decoder__gen_ete_config(t_params, &trace_config_ete);
                decoder->decoder_name = OCSD_BUILTIN_DCD_ETE;
                trace_config = &trace_config_ete;
@@ -688,6 +691,10 @@ cs_etm_decoder__create_etm_decoder(struct cs_etm_decoder_params *d_params,
                return -1;
        }
 
+       /* if the CPU has no trace ID associated, no decoder needed */
+       if (csid == CORESIGHT_TRACE_ID_UNUSED_VAL)
+               return 0;
+
        if (d_params->operation == CS_ETM_OPERATION_DECODE) {
                if (ocsd_dt_create_decoder(decoder->dcd_tree,
                                           decoder->decoder_name,
index 5fc9c28..94e2d02 100644 (file)
@@ -220,6 +220,143 @@ static int cs_etm__map_trace_id(u8 trace_chan_id, u64 *cpu_metadata)
        return 0;
 }
 
+static int cs_etm__metadata_get_trace_id(u8 *trace_chan_id, u64 *cpu_metadata)
+{
+       u64 cs_etm_magic = cpu_metadata[CS_ETM_MAGIC];
+
+       switch (cs_etm_magic) {
+       case __perf_cs_etmv3_magic:
+               *trace_chan_id = (u8)(cpu_metadata[CS_ETM_ETMTRACEIDR] &
+                                     CORESIGHT_TRACE_ID_VAL_MASK);
+               break;
+       case __perf_cs_etmv4_magic:
+       case __perf_cs_ete_magic:
+               *trace_chan_id = (u8)(cpu_metadata[CS_ETMV4_TRCTRACEIDR] &
+                                     CORESIGHT_TRACE_ID_VAL_MASK);
+               break;
+       default:
+               return -EINVAL;
+       }
+       return 0;
+}
+
+/*
+ * update metadata trace ID from the value found in the AUX_HW_INFO packet.
+ * This will also clear the CORESIGHT_TRACE_ID_UNUSED_FLAG flag if present.
+ */
+static int cs_etm__metadata_set_trace_id(u8 trace_chan_id, u64 *cpu_metadata)
+{
+       u64 cs_etm_magic = cpu_metadata[CS_ETM_MAGIC];
+
+       switch (cs_etm_magic) {
+       case __perf_cs_etmv3_magic:
+                cpu_metadata[CS_ETM_ETMTRACEIDR] = trace_chan_id;
+               break;
+       case __perf_cs_etmv4_magic:
+       case __perf_cs_ete_magic:
+               cpu_metadata[CS_ETMV4_TRCTRACEIDR] = trace_chan_id;
+               break;
+
+       default:
+               return -EINVAL;
+       }
+       return 0;
+}
+
+/*
+ * FIELD_GET (linux/bitfield.h) not available outside kernel code,
+ * and the header contains too many dependencies to just copy over,
+ * so roll our own based on the original
+ */
+#define __bf_shf(x) (__builtin_ffsll(x) - 1)
+#define FIELD_GET(_mask, _reg)                                         \
+       ({                                                              \
+               (typeof(_mask))(((_reg) & (_mask)) >> __bf_shf(_mask)); \
+       })
+
+/*
+ * Handle the PERF_RECORD_AUX_OUTPUT_HW_ID event.
+ *
+ * The payload associates the Trace ID and the CPU.
+ * The routine is tolerant of seeing multiple packets with the same association,
+ * but a CPU / Trace ID association changing during a session is an error.
+ */
+static int cs_etm__process_aux_output_hw_id(struct perf_session *session,
+                                           union perf_event *event)
+{
+       struct cs_etm_auxtrace *etm;
+       struct perf_sample sample;
+       struct int_node *inode;
+       struct evsel *evsel;
+       u64 *cpu_data;
+       u64 hw_id;
+       int cpu, version, err;
+       u8 trace_chan_id, curr_chan_id;
+
+       /* extract and parse the HW ID */
+       hw_id = event->aux_output_hw_id.hw_id;
+       version = FIELD_GET(CS_AUX_HW_ID_VERSION_MASK, hw_id);
+       trace_chan_id = FIELD_GET(CS_AUX_HW_ID_TRACE_ID_MASK, hw_id);
+
+       /* check that we can handle this version */
+       if (version > CS_AUX_HW_ID_CURR_VERSION)
+               return -EINVAL;
+
+       /* get access to the etm metadata */
+       etm = container_of(session->auxtrace, struct cs_etm_auxtrace, auxtrace);
+       if (!etm || !etm->metadata)
+               return -EINVAL;
+
+       /* parse the sample to get the CPU */
+       evsel = evlist__event2evsel(session->evlist, event);
+       if (!evsel)
+               return -EINVAL;
+       err = evsel__parse_sample(evsel, event, &sample);
+       if (err)
+               return err;
+       cpu = sample.cpu;
+       if (cpu == -1) {
+               /* no CPU in the sample - possibly recorded with an old version of perf */
+               pr_err("CS_ETM: no CPU AUX_OUTPUT_HW_ID sample. Use compatible perf to record.");
+               return -EINVAL;
+       }
+
+       /* See if the ID is mapped to a CPU, and it matches the current CPU */
+       inode = intlist__find(traceid_list, trace_chan_id);
+       if (inode) {
+               cpu_data = inode->priv;
+               if ((int)cpu_data[CS_ETM_CPU] != cpu) {
+                       pr_err("CS_ETM: map mismatch between HW_ID packet CPU and Trace ID\n");
+                       return -EINVAL;
+               }
+
+               /* check that the mapped ID matches */
+               err = cs_etm__metadata_get_trace_id(&curr_chan_id, cpu_data);
+               if (err)
+                       return err;
+               if (curr_chan_id != trace_chan_id) {
+                       pr_err("CS_ETM: mismatch between CPU trace ID and HW_ID packet ID\n");
+                       return -EINVAL;
+               }
+
+               /* mapped and matched - return OK */
+               return 0;
+       }
+
+       /* not one we've seen before - lets map it */
+       cpu_data = etm->metadata[cpu];
+       err = cs_etm__map_trace_id(trace_chan_id, cpu_data);
+       if (err)
+               return err;
+
+       /*
+        * if we are picking up the association from the packet, need to plug
+        * the correct trace ID into the metadata for setting up decoders later.
+        */
+       err = cs_etm__metadata_set_trace_id(trace_chan_id, cpu_data);
+       return err;
+}
+
 void cs_etm__etmq_set_traceid_queue_timestamp(struct cs_etm_queue *etmq,
                                              u8 trace_chan_id)
 {
@@ -2668,11 +2805,16 @@ static int cs_etm__queue_aux_fragment(struct perf_session *session, off_t file_o
        }
 
        /*
-        * In per-thread mode, CPU is set to -1, but TID will be set instead. See
-        * auxtrace_mmap_params__set_idx(). Return 'not found' if neither CPU nor TID match.
+        * In per-thread mode, auxtrace CPU is set to -1, but TID will be set instead. See
+        * auxtrace_mmap_params__set_idx(). However, the sample AUX event will contain a
+        * CPU as we set this always for the AUX_OUTPUT_HW_ID event.
+        * So now compare only TIDs if auxtrace CPU is -1, and CPUs if auxtrace CPU is not -1.
+        * Return 'not found' if mismatch.
         */
-       if ((auxtrace_event->cpu == (__u32) -1 && auxtrace_event->tid != sample->tid) ||
-                       auxtrace_event->cpu != sample->cpu)
+       if (auxtrace_event->cpu == (__u32) -1) {
+               if (auxtrace_event->tid != sample->tid)
+                       return 1;
+       } else if (auxtrace_event->cpu != sample->cpu)
                return 1;
 
        if (aux_event->flags & PERF_AUX_FLAG_OVERWRITE) {
@@ -2721,6 +2863,17 @@ static int cs_etm__queue_aux_fragment(struct perf_session *session, off_t file_o
        return 1;
 }
 
+static int cs_etm__process_aux_hw_id_cb(struct perf_session *session, union perf_event *event,
+                                       u64 offset __maybe_unused, void *data __maybe_unused)
+{
+       /* look to handle PERF_RECORD_AUX_OUTPUT_HW_ID early to ensure decoders can be set up */
+       if (event->header.type == PERF_RECORD_AUX_OUTPUT_HW_ID) {
+               (*(int *)data)++; /* increment found count */
+               return cs_etm__process_aux_output_hw_id(session, event);
+       }
+       return 0;
+}
+
 static int cs_etm__queue_aux_records_cb(struct perf_session *session, union perf_event *event,
                                        u64 offset __maybe_unused, void *data __maybe_unused)
 {
@@ -2839,13 +2992,13 @@ static int cs_etm__map_trace_ids_metadata(int num_cpu, u64 **metadata)
                cs_etm_magic = metadata[i][CS_ETM_MAGIC];
                switch (cs_etm_magic) {
                case __perf_cs_etmv3_magic:
-                       trace_chan_id = (u8)((metadata[i][CS_ETM_ETMTRACEIDR]) &
-                                            CORESIGHT_TRACE_ID_VAL_MASK);
+                       metadata[i][CS_ETM_ETMTRACEIDR] &= CORESIGHT_TRACE_ID_VAL_MASK;
+                       trace_chan_id = (u8)(metadata[i][CS_ETM_ETMTRACEIDR]);
                        break;
                case __perf_cs_etmv4_magic:
                case __perf_cs_ete_magic:
-                       trace_chan_id = (u8)((metadata[i][CS_ETMV4_TRCTRACEIDR]) &
-                                             CORESIGHT_TRACE_ID_VAL_MASK);
+                       metadata[i][CS_ETMV4_TRCTRACEIDR] &= CORESIGHT_TRACE_ID_VAL_MASK;
+                       trace_chan_id = (u8)(metadata[i][CS_ETMV4_TRCTRACEIDR]);
                        break;
                default:
                        /* unknown magic number */
@@ -2858,6 +3011,35 @@ static int cs_etm__map_trace_ids_metadata(int num_cpu, u64 **metadata)
        return 0;
 }
 
+/*
+ * If we found AUX_HW_ID packets, then set any metadata marked as unused to the
+ * unused value to reduce the number of unneeded decoders created.
+ */
+static int cs_etm__clear_unused_trace_ids_metadata(int num_cpu, u64 **metadata)
+{
+       u64 cs_etm_magic;
+       int i;
+
+       for (i = 0; i < num_cpu; i++) {
+               cs_etm_magic = metadata[i][CS_ETM_MAGIC];
+               switch (cs_etm_magic) {
+               case __perf_cs_etmv3_magic:
+                       if (metadata[i][CS_ETM_ETMTRACEIDR] & CORESIGHT_TRACE_ID_UNUSED_FLAG)
+                               metadata[i][CS_ETM_ETMTRACEIDR] = CORESIGHT_TRACE_ID_UNUSED_VAL;
+                       break;
+               case __perf_cs_etmv4_magic:
+               case __perf_cs_ete_magic:
+                       if (metadata[i][CS_ETMV4_TRCTRACEIDR] & CORESIGHT_TRACE_ID_UNUSED_FLAG)
+                               metadata[i][CS_ETMV4_TRCTRACEIDR] = CORESIGHT_TRACE_ID_UNUSED_VAL;
+                       break;
+               default:
+                       /* unknown magic number */
+                       return -EINVAL;
+               }
+       }
+       return 0;
+}
+
 int cs_etm__process_auxtrace_info_full(union perf_event *event,
                                       struct perf_session *session)
 {
@@ -2869,6 +3051,7 @@ int cs_etm__process_auxtrace_info_full(union perf_event *event,
        int priv_size = 0;
        int num_cpu;
        int err = 0;
+       int aux_hw_id_found;
        int i, j;
        u64 *ptr = NULL;
        u64 **metadata = NULL;
@@ -3017,8 +3200,43 @@ int cs_etm__process_auxtrace_info_full(union perf_event *event,
        if (err)
                goto err_delete_thread;
 
-       /* before aux records are queued, need to map metadata to trace IDs */
-       err = cs_etm__map_trace_ids_metadata(num_cpu, metadata);
+       /*
+        * Map Trace ID values to CPU metadata.
+        *
+        * Trace metadata will always contain Trace ID values from the legacy algorithm. If the
+        * files has been recorded by a "new" perf updated to handle AUX_HW_ID then the metadata
+        * ID value will also have the CORESIGHT_TRACE_ID_UNUSED_FLAG set.
+        *
+        * The updated kernel drivers that use AUX_HW_ID to sent Trace IDs will attempt to use
+        * the same IDs as the old algorithm as far as is possible, unless there are clashes
+        * in which case a different value will be used. This means an older perf may still
+        * be able to record and read files generate on a newer system.
+        *
+        * For a perf able to interpret AUX_HW_ID packets we first check for the presence of
+        * those packets. If they are there then the values will be mapped and plugged into
+        * the metadata. We then set any remaining metadata values with the used flag to a
+        * value CORESIGHT_TRACE_ID_UNUSED_VAL - which indicates no decoder is required.
+        *
+        * If no AUX_HW_ID packets are present - which means a file recorded on an old kernel
+        * then we map Trace ID values to CPU directly from the metadata - clearing any unused
+        * flags if present.
+        */
+
+       /* first scan for AUX_OUTPUT_HW_ID records to map trace ID values to CPU metadata */
+       aux_hw_id_found = 0;
+       err = perf_session__peek_events(session, session->header.data_offset,
+                                       session->header.data_size,
+                                       cs_etm__process_aux_hw_id_cb, &aux_hw_id_found);
+       if (err)
+               goto err_delete_thread;
+
+       /* if HW ID found then clear any unused metadata ID values */
+       if (aux_hw_id_found)
+               err = cs_etm__clear_unused_trace_ids_metadata(num_cpu, metadata);
+       /* otherwise, this is a file with metadata values only, map from metadata */
+       else
+               err = cs_etm__map_trace_ids_metadata(num_cpu, metadata);
+
        if (err)
                goto err_delete_thread;
 
@@ -3027,14 +3245,6 @@ int cs_etm__process_auxtrace_info_full(union perf_event *event,
                goto err_delete_thread;
 
        etm->data_queued = etm->queues.populated;
-       /*
-        * Print warning in pipe mode, see cs_etm__process_auxtrace_event() and
-        * cs_etm__queue_aux_fragment() for details relating to limitations.
-        */
-       if (!etm->data_queued)
-               pr_warning("CS ETM warning: Coresight decode and TRBE support requires random file access.\n"
-                          "Continuing with best effort decoding in piped mode.\n\n");
-
        return 0;
 
 err_delete_thread: