Re: [PATCH v4 08/13] perf: cs-etm: Move mapping of Trace ID and cpu into helper function

[James Clark <james.clark@arm.com>]

On 23/08/2022 10:10, Mike Leach wrote:
> The information to associate Trace ID and CPU will be changing.
> 
> Drivers will start outputting this as a hardware ID packet in the data
> file which if present will be used in preference to the AUXINFO values.
> 
> To prepare for this we provide a helper functions to do the individual ID
> mapping, and one to extract the IDs from the completed metadata blocks.
> 
> Signed-off-by: Mike Leach <mike.leach@linaro.org>

Reviewed-by: James Clark <james.clark@arm.com>
> ---
>  tools/include/linux/coresight-pmu.h |  5 ++
>  tools/perf/util/cs-etm.c            | 92 +++++++++++++++++++----------
>  tools/perf/util/cs-etm.h            | 14 ++++-
>  3 files changed, 77 insertions(+), 34 deletions(-)
> 
> diff --git a/tools/include/linux/coresight-pmu.h b/tools/include/linux/coresight-pmu.h
> index 6c2fd6cc5a98..db9c7c0abb6a 100644
> --- a/tools/include/linux/coresight-pmu.h
> +++ b/tools/include/linux/coresight-pmu.h
> @@ -7,9 +7,14 @@
>  #ifndef _LINUX_CORESIGHT_PMU_H
>  #define _LINUX_CORESIGHT_PMU_H
>  
> +#include <linux/bits.h>
> +
>  #define CORESIGHT_ETM_PMU_NAME "cs_etm"
>  #define CORESIGHT_ETM_PMU_SEED  0x10
>  
> +/* CoreSight trace ID is currently the bottom 7 bits of the value */
> +#define CORESIGHT_TRACE_ID_VAL_MASK	GENMASK(6, 0)
> +
>  /*
>   * Below are the definition of bit offsets for perf option, and works as
>   * arbitrary values for all ETM versions.
> diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
> index 8b95fb3c4d7b..48aaa2843ee2 100644
> --- a/tools/perf/util/cs-etm.c
> +++ b/tools/perf/util/cs-etm.c
> @@ -193,6 +193,30 @@ int cs_etm__get_pid_fmt(u8 trace_chan_id, u64 *pid_fmt)
>  	return 0;
>  }
>  
> +static int cs_etm__map_trace_id(u8 trace_chan_id, u64 *cpu_metadata)
> +{
> +	struct int_node *inode;
> +
> +	/* Get an RB node for this CPU */
> +	inode = intlist__findnew(traceid_list, trace_chan_id);
> +
> +	/* Something went wrong, no need to continue */
> +	if (!inode)
> +		return -ENOMEM;
> +
> +	/*
> +	 * The node for that CPU should not be taken.
> +	 * Back out if that's the case.
> +	 */
> +	if (inode->priv)
> +		return -EINVAL;
> +
> +	/* All good, associate the traceID with the metadata pointer */
> +	inode->priv = cpu_metadata;
> +
> +	return 0;
> +}
> +
>  void cs_etm__etmq_set_traceid_queue_timestamp(struct cs_etm_queue *etmq,
>  					      u8 trace_chan_id)
>  {
> @@ -2881,18 +2905,47 @@ static int cs_etm__queue_aux_records(struct perf_session *session)
>  	return 0;
>  }
>  
> +/* map trace ids to correct metadata block, from information in metadata */
> +static int cs_etm__map_trace_ids_metadata(int num_cpu, u64 **metadata)
> +{
> +	u64 cs_etm_magic;
> +	u8 trace_chan_id;
> +	int i, err;
> +
> +	for (i = 0; i < num_cpu; i++) {
> +		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);
> +			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);
> +			break;
> +		default:
> +			/* unknown magic number */
> +			return -EINVAL;
> +		}
> +		err = cs_etm__map_trace_id(trace_chan_id, metadata[i]);
> +		if (err)
> +			return err;
> +	}
> +	return 0;
> +}
> +
>  int cs_etm__process_auxtrace_info(union perf_event *event,
>  				  struct perf_session *session)
>  {
>  	struct perf_record_auxtrace_info *auxtrace_info = &event->auxtrace_info;
>  	struct cs_etm_auxtrace *etm = NULL;
> -	struct int_node *inode;
>  	unsigned int pmu_type;
>  	int event_header_size = sizeof(struct perf_event_header);
>  	int info_header_size;
>  	int total_size = auxtrace_info->header.size;
>  	int priv_size = 0;
> -	int num_cpu, trcidr_idx;
> +	int num_cpu;
>  	int err = 0;
>  	int i, j;
>  	u64 *ptr, *hdr = NULL;
> @@ -2962,23 +3015,13 @@ int cs_etm__process_auxtrace_info(union perf_event *event,
>  				cs_etm__create_meta_blk(ptr, &i,
>  							CS_ETM_PRIV_MAX,
>  							CS_ETM_NR_TRC_PARAMS_V0);
> -
> -			/* The traceID is our handle */
> -			trcidr_idx = CS_ETM_ETMTRACEIDR;
> -
>  		} else if (ptr[i] == __perf_cs_etmv4_magic) {
>  			metadata[j] =
>  				cs_etm__create_meta_blk(ptr, &i,
>  							CS_ETMV4_PRIV_MAX,
>  							CS_ETMV4_NR_TRC_PARAMS_V0);
> -
> -			/* The traceID is our handle */
> -			trcidr_idx = CS_ETMV4_TRCTRACEIDR;
>  		} else if (ptr[i] == __perf_cs_ete_magic) {
>  			metadata[j] = cs_etm__create_meta_blk(ptr, &i, CS_ETE_PRIV_MAX, -1);
> -
> -			/* ETE shares first part of metadata with ETMv4 */
> -			trcidr_idx = CS_ETMV4_TRCTRACEIDR;
>  		} else {
>  			ui__error("CS ETM Trace: Unrecognised magic number %#"PRIx64". File could be from a newer version of perf.\n",
>  				  ptr[i]);
> @@ -2990,26 +3033,6 @@ int cs_etm__process_auxtrace_info(union perf_event *event,
>  			err = -ENOMEM;
>  			goto err_free_metadata;
>  		}
> -
> -		/* Get an RB node for this CPU */
> -		inode = intlist__findnew(traceid_list, metadata[j][trcidr_idx]);
> -
> -		/* Something went wrong, no need to continue */
> -		if (!inode) {
> -			err = -ENOMEM;
> -			goto err_free_metadata;
> -		}
> -
> -		/*
> -		 * The node for that CPU should not be taken.
> -		 * Back out if that's the case.
> -		 */
> -		if (inode->priv) {
> -			err = -EINVAL;
> -			goto err_free_metadata;
> -		}
> -		/* All good, associate the traceID with the metadata pointer */
> -		inode->priv = metadata[j];
>  	}
>  
>  	/*
> @@ -3090,6 +3113,11 @@ int cs_etm__process_auxtrace_info(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);
> +	if (err)
> +		goto err_delete_thread;
> +
>  	err = cs_etm__queue_aux_records(session);
>  	if (err)
>  		goto err_delete_thread;
> diff --git a/tools/perf/util/cs-etm.h b/tools/perf/util/cs-etm.h
> index 90c83f932d9a..712a6f855f0e 100644
> --- a/tools/perf/util/cs-etm.h
> +++ b/tools/perf/util/cs-etm.h
> @@ -28,13 +28,17 @@ enum {
>  /*
>   * Update the version for new format.
>   *
> - * New version 1 format adds a param count to the per cpu metadata.
> + * Version 1: format adds a param count to the per cpu metadata.
>   * This allows easy adding of new metadata parameters.
>   * Requires that new params always added after current ones.
>   * Also allows client reader to handle file versions that are different by
>   * checking the number of params in the file vs the number expected.
> + *
> + * Version 2: Drivers will use PERF_RECORD_AUX_OUTPUT_HW_ID to output
> + * CoreSight Trace ID. ...TRACEIDR metadata will be set to unused ID.
>   */
> -#define CS_HEADER_CURRENT_VERSION 1
> +#define CS_HEADER_CURRENT_VERSION	2
> +#define CS_AUX_HW_ID_VERSION_MIN	2
>  
>  /* Beginning of header common to both ETMv3 and V4 */
>  enum {
> @@ -85,6 +89,12 @@ enum {
>  	CS_ETE_PRIV_MAX
>  };
>  
> +/*
> + * Check for valid CoreSight trace ID. If an invalid value is present in the metadata,
> + * then IDs are present in the hardware ID packet in the data file.
> + */
> +#define CS_IS_VALID_TRACE_ID(id) ((id > 0) && (id < 0x70))
> +
>  /*
>   * ETMv3 exception encoding number:
>   * See Embedded Trace Macrocell specification (ARM IHI 0014Q)