Re: [PATCH 05/10] perf tools: Add support for decoding CoreSight trace data

[Mike Leach]

Hi Leo,

The OCSD_GEN_TRC_ELEM_ADDR_NACC element indicates that the decoder
does not have an code image mapping for the address contained in the
trace, at the location described by this element. the payload for the
NACC element is the memory location it could not address.
This means that it cannot correctly follow the instruction execution
sequence described by the individual trace packets.

The dump option works because we do not need to follow the execution
sequence to dump raw trace packets.

It is not clear to me if the perf script option as you specified is
mapping the vmlinux image into the decoder.

Regards

Mike

On 30 December 2017 at 00:33, Leo Yan <leo.yan@xxxxxxxxxx> wrote:
> Hi Mathieu, Mike,
>
> On Fri, Dec 15, 2017 at 09:44:54AM -0700, Mathieu Poirier wrote:
>> Adding functionality to create a CoreSight trace decoder capable
>> of decoding trace data pushed by a client application.
>>
>> Co-authored-by: Tor Jeremiassen <tor@xxxxxx>
>> Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
>> ---
>>  tools/perf/util/cs-etm-decoder/cs-etm-decoder.c | 119 ++++++++++++++++++++++++
>>  1 file changed, 119 insertions(+)
>>
>> diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
>> index 6a4c86b1431f..57b020b0b36f 100644
>> --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
>> +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
>> @@ -200,6 +200,121 @@ static void cs_etm_decoder__clear_buffer(struct cs_etm_decoder *decoder)
>>       }
>>  }
>>
>> +static ocsd_datapath_resp_t
>> +cs_etm_decoder__buffer_packet(struct cs_etm_decoder *decoder,
>> +                           const ocsd_generic_trace_elem *elem,
>> +                           const u8 trace_chan_id,
>> +                           enum cs_etm_sample_type sample_type)
>> +{
>> +     u32 et = 0;
>> +     struct int_node *inode = NULL;
>> +
>> +     if (decoder->packet_count >= MAX_BUFFER - 1)
>> +             return OCSD_RESP_FATAL_SYS_ERR;
>> +
>> +     /* Search the RB tree for the cpu associated with this traceID */
>> +     inode = intlist__find(traceid_list, trace_chan_id);
>> +     if (!inode)
>> +             return OCSD_RESP_FATAL_SYS_ERR;
>> +
>> +     et = decoder->tail;
>> +     decoder->packet_buffer[et].sample_type = sample_type;
>> +     decoder->packet_buffer[et].start_addr = elem->st_addr;
>> +     decoder->packet_buffer[et].end_addr = elem->en_addr;
>> +     decoder->packet_buffer[et].exc = false;
>> +     decoder->packet_buffer[et].exc_ret = false;
>> +     decoder->packet_buffer[et].cpu = *((int *)inode->priv);
>> +
>> +     /* Wrap around if need be */
>> +     et = (et + 1) & (MAX_BUFFER - 1);
>> +
>> +     decoder->tail = et;
>> +     decoder->packet_count++;
>> +
>> +     if (decoder->packet_count == MAX_BUFFER - 1)
>> +             return OCSD_RESP_WAIT;
>> +
>> +     return OCSD_RESP_CONT;
>> +}
>> +
>> +static ocsd_datapath_resp_t cs_etm_decoder__gen_trace_elem_printer(
>> +                             const void *context,
>> +                             const ocsd_trc_index_t indx __maybe_unused,
>> +                             const u8 trace_chan_id __maybe_unused,
>> +                             const ocsd_generic_trace_elem *elem)
>> +{
>> +     ocsd_datapath_resp_t resp = OCSD_RESP_CONT;
>> +     struct cs_etm_decoder *decoder = (struct cs_etm_decoder *) context;
>
> After apply this patch set and build 'perf' tool with linking
> OpenCSDv0.8.0 libs, I can everytime OpenCSD parses 'elem->elem_type'
> is OCSD_GEN_TRC_ELEM_ADDR_NACC but not OCSD_GEN_TRC_ELEM_INSTR_RANGE.
>
> As result, the 'perf' tool can dump the raw data with '-D' option but
> it cannot analyze the symbol and symbol offset with below command:
>
> ./perf script -v -a -F cpu,event,ip,sym,symoff -i ./perf.data -k vmlinux
> --kallsyms ./System.map
>
> Have uploaded perf.data/vmlinux/System.map in the folder:
> http://people.linaro.org/~leo.yan/binaries/perf_4.15_r4/
>
> Thanks,
> Leo Yan
>
>> +     switch (elem->elem_type) {
>> +     case OCSD_GEN_TRC_ELEM_UNKNOWN:
>> +             break;
>> +     case OCSD_GEN_TRC_ELEM_NO_SYNC:
>> +             decoder->trace_on = false;
>> +             break;
>> +     case OCSD_GEN_TRC_ELEM_TRACE_ON:
>> +             decoder->trace_on = true;
>> +             break;
>> +     case OCSD_GEN_TRC_ELEM_INSTR_RANGE:
>> +             resp = cs_etm_decoder__buffer_packet(decoder, elem,
>> +                                                  trace_chan_id,
>> +                                                  CS_ETM_RANGE);
>> +             break;
>> +     case OCSD_GEN_TRC_ELEM_EXCEPTION:
>> +             decoder->packet_buffer[decoder->tail].exc = true;
>> +             break;
>> +     case OCSD_GEN_TRC_ELEM_EXCEPTION_RET:
>> +             decoder->packet_buffer[decoder->tail].exc_ret = true;
>> +             break;
>> +     case OCSD_GEN_TRC_ELEM_PE_CONTEXT:
>> +     case OCSD_GEN_TRC_ELEM_EO_TRACE:
>> +     case OCSD_GEN_TRC_ELEM_ADDR_NACC:
>> +     case OCSD_GEN_TRC_ELEM_TIMESTAMP:
>> +     case OCSD_GEN_TRC_ELEM_CYCLE_COUNT:
>> +     case OCSD_GEN_TRC_ELEM_ADDR_UNKNOWN:
>> +     case OCSD_GEN_TRC_ELEM_EVENT:
>> +     case OCSD_GEN_TRC_ELEM_SWTRACE:
>> +     case OCSD_GEN_TRC_ELEM_CUSTOM:
>> +     default:
>> +             break;
>> +     }
>> +
>> +     return resp;
>> +}
>> +
>> +static int cs_etm_decoder__create_etm_packet_decoder(
>> +                                     struct cs_etm_trace_params *t_params,
>> +                                     struct cs_etm_decoder *decoder)
>> +{
>> +     const char *decoder_name;
>> +     ocsd_etmv4_cfg trace_config_etmv4;
>> +     void *trace_config;
>> +     u8 csid;
>> +
>> +     switch (t_params->protocol) {
>> +     case CS_ETM_PROTO_ETMV4i:
>> +             cs_etm_decoder__gen_etmv4_config(t_params, &trace_config_etmv4);
>> +             decoder_name = OCSD_BUILTIN_DCD_ETMV4I;
>> +             trace_config = &trace_config_etmv4;
>> +             break;
>> +     default:
>> +             return -1;
>> +     }
>> +
>> +     if (ocsd_dt_create_decoder(decoder->dcd_tree,
>> +                                  decoder_name,
>> +                                  OCSD_CREATE_FLG_FULL_DECODER,
>> +                                  trace_config, &csid))
>> +             return -1;
>> +
>> +     if (ocsd_dt_set_gen_elem_outfn(decoder->dcd_tree,
>> +                                    cs_etm_decoder__gen_trace_elem_printer,
>> +                                    decoder))
>> +             return -1;
>> +
>> +     return 0;
>> +}
>> +
>>  static int
>>  cs_etm_decoder__create_etm_decoder(struct cs_etm_decoder_params *d_params,
>>                                  struct cs_etm_trace_params *t_params,
>> @@ -208,6 +323,10 @@ cs_etm_decoder__create_etm_decoder(struct cs_etm_decoder_params *d_params,
>>       if (d_params->operation == CS_ETM_OPERATION_PRINT)
>>               return cs_etm_decoder__create_etm_packet_printer(t_params,
>>                                                                decoder);
>> +     else if (d_params->operation == CS_ETM_OPERATION_DECODE)
>> +             return cs_etm_decoder__create_etm_packet_decoder(t_params,
>> +                                                              decoder);
>> +
>>       return -1;
>>  }
>>
>> --
>> 2.7.4
>>
>
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-- 
Mike Leach
Principal Engineer, ARM Ltd.
Blackburn Design Centre. UK