Re: [PATCH v2 4/9] perf cs-etm: Save TRCDEVARCH register

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Fri, Sep 03, 2021 at 10:08:22AM +0100, Suzuki K Poulose escreveu:
> Hi James
> 
> On 06/08/2021 14:41, James Clark wrote:
> > When ETE is present save the TRCDEVARCH register and set a new magic
> > number. It will be used to configure the decoder in a later commit.
> > 
> > Old versions of perf will not be able to open files with this new magic
> > number, but old files will still work with newer versions of perf.
> > 
> 
> The patch looks good to me. There are some minor style related comments
> below.
> 
> > Signed-off-by: James Clark <james.clark@arm.com>
> > ---
> >   tools/perf/arch/arm/util/cs-etm.c | 49 +++++++++++++++++++++++++++----
> >   tools/perf/util/cs-etm.c          | 16 ++++++++--
> >   tools/perf/util/cs-etm.h          | 10 +++++++
> >   3 files changed, 68 insertions(+), 7 deletions(-)
> > 
> > diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c
> > index ecb6fa55a210..e3500b79d972 100644
> > --- a/tools/perf/arch/arm/util/cs-etm.c
> > +++ b/tools/perf/arch/arm/util/cs-etm.c
> > @@ -47,15 +47,17 @@ static const char *metadata_etmv3_ro[CS_ETM_PRIV_MAX] = {
> >   	[CS_ETM_ETMIDR]		= "mgmt/etmidr",
> >   };
> > -static const char *metadata_etmv4_ro[CS_ETMV4_PRIV_MAX] = {
> > +static const char * const metadata_etmv4_ro[] = {
> >   	[CS_ETMV4_TRCIDR0]		= "trcidr/trcidr0",
> >   	[CS_ETMV4_TRCIDR1]		= "trcidr/trcidr1",
> >   	[CS_ETMV4_TRCIDR2]		= "trcidr/trcidr2",
> >   	[CS_ETMV4_TRCIDR8]		= "trcidr/trcidr8",
> >   	[CS_ETMV4_TRCAUTHSTATUS]	= "mgmt/trcauthstatus",
> > +	[CS_ETE_TRCDEVARCH]		= "mgmt/trcdevarch"
> >   };
> >   static bool cs_etm_is_etmv4(struct auxtrace_record *itr, int cpu);
> > +static bool cs_etm_is_ete(struct auxtrace_record *itr, int cpu);
> >   static int cs_etm_set_context_id(struct auxtrace_record *itr,
> >   				 struct evsel *evsel, int cpu)
> > @@ -533,7 +535,7 @@ cs_etm_info_priv_size(struct auxtrace_record *itr __maybe_unused,
> >   		      struct evlist *evlist __maybe_unused)
> >   {
> >   	int i;
> > -	int etmv3 = 0, etmv4 = 0;
> > +	int etmv3 = 0, etmv4 = 0, ete = 0;
> >   	struct perf_cpu_map *event_cpus = evlist->core.cpus;
> >   	struct perf_cpu_map *online_cpus = perf_cpu_map__new(NULL);
> > @@ -544,7 +546,9 @@ cs_etm_info_priv_size(struct auxtrace_record *itr __maybe_unused,
> >   			    !cpu_map__has(online_cpus, i))
> >   				continue;
> > -			if (cs_etm_is_etmv4(itr, i))
> > +			if (cs_etm_is_ete(itr, i))
> > +				ete++;
> > +			else if (cs_etm_is_etmv4(itr, i))
> >   				etmv4++;
> >   			else
> >   				etmv3++;
> > @@ -555,7 +559,9 @@ cs_etm_info_priv_size(struct auxtrace_record *itr __maybe_unused,
> >   			if (!cpu_map__has(online_cpus, i))
> >   				continue;
> > -			if (cs_etm_is_etmv4(itr, i))
> > +			if (cs_etm_is_ete(itr, i))
> > +				ete++;
> > +			else if (cs_etm_is_etmv4(itr, i))
> >   				etmv4++;
> >   			else
> >   				etmv3++;
> > @@ -565,6 +571,7 @@ cs_etm_info_priv_size(struct auxtrace_record *itr __maybe_unused,
> >   	perf_cpu_map__put(online_cpus);
> >   	return (CS_ETM_HEADER_SIZE +
> > +	       (ete   * CS_ETE_PRIV_SIZE) +
> >   	       (etmv4 * CS_ETMV4_PRIV_SIZE) +
> >   	       (etmv3 * CS_ETMV3_PRIV_SIZE));
> >   }
> > @@ -607,6 +614,27 @@ static int cs_etm_get_ro(struct perf_pmu *pmu, int cpu, const char *path)
> >   	return val;
> >   }
> > +#define TRCDEVARCH_ARCHPART_SHIFT 0
> > +#define TRCDEVARCH_ARCHPART_MASK  GENMASK(11, 0)
> > +#define TRCDEVARCH_ARCHPART(x)    (((x) & TRCDEVARCH_ARCHPART_MASK) >> TRCDEVARCH_ARCHPART_SHIFT)
> > +
> > +#define TRCDEVARCH_ARCHVER_SHIFT 12
> > +#define TRCDEVARCH_ARCHVER_MASK  GENMASK(15, 12)
> > +#define TRCDEVARCH_ARCHVER(x)    (((x) & TRCDEVARCH_ARCHVER_MASK) >> TRCDEVARCH_ARCHVER_SHIFT)
> > +
> > +static bool cs_etm_is_ete(struct auxtrace_record *itr, int cpu)
> > +{
> > +	struct cs_etm_recording *ptr = container_of(itr, struct cs_etm_recording, itr);
> > +	struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
> > +	int trcdevarch = cs_etm_get_ro(cs_etm_pmu, cpu, metadata_etmv4_ro[CS_ETE_TRCDEVARCH]);
> > +
> > +	/*
> > +	 * ETE if ARCHVER is 5 (ARCHVER is 4 for ETM) and ARCHPART is 0xA13.
> > +	 * See ETM_DEVARCH_ETE_ARCH in coresight-etm4x.h
> > +	 */
> > +	return TRCDEVARCH_ARCHVER(trcdevarch) == 5 && TRCDEVARCH_ARCHPART(trcdevarch) == 0xA13;
> > +}
> > +
> >   static void cs_etm_save_etmv4_header(__u64 data[], struct auxtrace_record *itr, int cpu)
> >   {
> >   	struct cs_etm_recording *ptr = container_of(itr, struct cs_etm_recording, itr);
> > @@ -640,7 +668,18 @@ static void cs_etm_get_metadata(int cpu, u32 *offset,
> >   	struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
> >   	/* first see what kind of tracer this cpu is affined to */
> > -	if (cs_etm_is_etmv4(itr, cpu)) {
> > +	if (cs_etm_is_ete(itr, cpu)) {
> > +		magic = __perf_cs_ete_magic;
> > +		/* ETE uses the same registers as ETMv4 plus TRCDEVARCH */
> > +		cs_etm_save_etmv4_header(&info->priv[*offset], itr, cpu);
> > +		info->priv[*offset + CS_ETE_TRCDEVARCH] =
> > +			cs_etm_get_ro(cs_etm_pmu, cpu,
> > +				      metadata_etmv4_ro[CS_ETE_TRCDEVARCH]);
> > +
> 
> minor nit: It may be nicer to have a helper function like we do for etmv4.
> i.e,
> 		cs_etm_save_ete_header();
> 
> to keep the code consistent.
> 
> > +		/* How much space was used */
> > +		increment = CS_ETE_PRIV_MAX;
> > +		nr_trc_params = CS_ETE_PRIV_MAX - CS_ETM_COMMON_BLK_MAX_V1;
> > +	} else if (cs_etm_is_etmv4(itr, cpu)) {
> >   		magic = __perf_cs_etmv4_magic;
> >   		cs_etm_save_etmv4_header(&info->priv[*offset], itr, cpu);
> > diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
> > index f4b2bff533f3..d540512a3c96 100644
> > --- a/tools/perf/util/cs-etm.c
> > +++ b/tools/perf/util/cs-etm.c
> 
> 
> >   		for (j = 0; j < total_params; j++, i++) {
> >   			/* if newer record - could be excess params */
> > -			if (j >= CS_ETMV4_PRIV_MAX)
> > +			if (j >= CS_ETE_PRIV_MAX)
> >   				fprintf(stdout, param_unk_fmt, j, val[i]);
> >   			else
> >   				fprintf(stdout, cs_etmv4_priv_fmts[j], val[i]);
> > @@ -2943,6 +2949,12 @@ int cs_etm__process_auxtrace_info(union perf_event *event,
> >   			/* 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);
> 
> minor nit: I would prefer the arguments to be split into the next line,
> rather than moving the function call to the next line. i.e,
> 
> 			metatdata[j] = cs_etm_create_meta_blk(ptr, &i,
> 							      ....

He did it for consistency with the previous else blocks, but I think it
should even be all in just one line, 92 chars is ok, I'd say.

Here I have:

  $ echo $COLUMNS
  273
  $

:-)

I did it as there are plenty of other lines in this file that are over
100 chars in width.
 						
> > +
> > +			/* ETE shares first part of metadata with ETMv4 */
> > +			trcidr_idx = CS_ETMV4_TRCTRACEIDR;
> >   		}
> >   		if (!metadata[j]) {
> > diff --git a/tools/perf/util/cs-etm.h b/tools/perf/util/cs-etm.h
> > index d65c7b19407d..08b84c21f065 100644
> > --- a/tools/perf/util/cs-etm.h
> > +++ b/tools/perf/util/cs-etm.h
> > @@ -76,6 +76,14 @@ enum {
> >   /* define fixed version 0 length - allow new format reader to read old files. */
> >   #define CS_ETMV4_NR_TRC_PARAMS_V0 (CS_ETMV4_TRCAUTHSTATUS - CS_ETMV4_TRCCONFIGR + 1)
> > +/* ETE metadata is ETMv4 plus TRCDEVARCH register and doesn't support header V0 since it was
> 
> minor nit: comment style.
> 
> 	/*
> 	 * ETE metadata...
> 	 *
> 	 */

Yeah, being even consistent with other multi line comments on this same
file.

- Arnaldo