linux-kernel - Re: [PATCH v6 4/8] perf cs-etm: Add exception number in exception packet

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Message-ID: <20190123210526.GD620@xps15>
Date:   Wed, 23 Jan 2019 14:05:26 -0700
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Leo Yan <leo.yan@...aro.org>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Mike Leach <mike.leach@...aro.org>,
        Robert Walker <robert.walker@....com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Coresight ML <coresight@...ts.linaro.org>
Subject: Re: [PATCH v6 4/8] perf cs-etm: Add exception number in exception
 packet

On Sat, Jan 19, 2019 at 09:43:43AM +0800, Leo Yan wrote:
> When an exception packet comes, it contains the information for
> exception number; the exception number indicates the exception types,
> so from it we can know if the exception is taken for interrupt,
> system call or other traps, etc.
> 
> This patch simply adds a field in cs_etm_packet struct, it records
> exception number for exception packet that will then be used to
> properly identify exception types to the perf synthesize mechanic.
> 
> Signed-off-by: Leo Yan <leo.yan@...aro.org>
> ---
>  .../perf/util/cs-etm-decoder/cs-etm-decoder.c | 20 +++++++++++++++----
>  .../perf/util/cs-etm-decoder/cs-etm-decoder.h |  1 +
>  2 files changed, 17 insertions(+), 4 deletions(-)
> 
> 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 e98ee49a1527..294efa76c9e3 100644
> --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
> +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
> @@ -294,6 +294,7 @@ static void cs_etm_decoder__clear_buffer(struct cs_etm_decoder *decoder)
>  		decoder->packet_buffer[i].last_instr_subtype = 0;
>  		decoder->packet_buffer[i].last_instr_cond = 0;
>  		decoder->packet_buffer[i].flags = 0;
> +		decoder->packet_buffer[i].exception_number = UINT32_MAX;
>  		decoder->packet_buffer[i].cpu = INT_MIN;
>  	}
>  }
> @@ -331,6 +332,7 @@ cs_etm_decoder__buffer_packet(struct cs_etm_decoder *decoder,
>  	decoder->packet_buffer[et].last_instr_subtype = 0;
>  	decoder->packet_buffer[et].last_instr_cond = 0;
>  	decoder->packet_buffer[et].flags = 0;
> +	decoder->packet_buffer[et].exception_number = UINT32_MAX;
>  
>  	if (decoder->packet_count == MAX_BUFFER - 1)
>  		return OCSD_RESP_WAIT;
> @@ -406,10 +408,20 @@ cs_etm_decoder__buffer_discontinuity(struct cs_etm_decoder *decoder,
>  
>  static ocsd_datapath_resp_t
>  cs_etm_decoder__buffer_exception(struct cs_etm_decoder *decoder,
> +				 const ocsd_generic_trace_elem *elem,
>  				 const uint8_t trace_chan_id)
> -{
> -	return cs_etm_decoder__buffer_packet(decoder, trace_chan_id,
> -					     CS_ETM_EXCEPTION);
> +{	int ret = 0;
> +	struct cs_etm_packet *packet;
> +
> +	ret = cs_etm_decoder__buffer_packet(decoder, trace_chan_id,
> +					    CS_ETM_EXCEPTION);
> +	if (ret != OCSD_RESP_CONT && ret != OCSD_RESP_WAIT)
> +		return ret;
> +
> +	packet = &decoder->packet_buffer[decoder->tail];
> +	packet->exception_number = elem->exception_number;
> +
> +	return ret;
>  }
>  
>  static ocsd_datapath_resp_t
> @@ -443,7 +455,7 @@ static ocsd_datapath_resp_t cs_etm_decoder__gen_trace_elem_printer(
>  						    trace_chan_id);
>  		break;
>  	case OCSD_GEN_TRC_ELEM_EXCEPTION:
> -		resp = cs_etm_decoder__buffer_exception(decoder,
> +		resp = cs_etm_decoder__buffer_exception(decoder, elem,
>  							trace_chan_id);
>  		break;
>  	case OCSD_GEN_TRC_ELEM_EXCEPTION_RET:
> diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h
> index 23600e57a215..012b4728a46f 100644
> --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h
> +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h
> @@ -46,6 +46,7 @@ struct cs_etm_packet {
>  	u32 last_instr_type;
>  	u32 last_instr_subtype;
>  	u32 flags;
> +	u32 exception_number;
>  	u8 last_instr_cond;
>  	u8 last_instr_taken_branch;
>  	u8 last_instr_size;

Reviewed-by: Mathieu Poirier <mathieu.poirier@...aro.org>

> -- 
> 2.17.1
>