Re: [RFC 01/17] perf tools: Configure contextID tracing in CPU-wide mode

On Wed, Apr 03, 2019 at 03:59:20PM +0800, Leo Yan wrote:

On Wed, Mar 06, 2019 at 03:59:26PM -0700, Mathieu Poirier wrote:

...

When operating in CPU-wide mode being notified of contextID changes is required so that the decoding mechanic is aware of the process context switch.

Signed-off-by: Mathieu Poirier mathieu.poirier@linaro.org

tools/perf/arch/arm/util/cs-etm.c | 126 +++++++++++++++++++++++++----- tools/perf/util/cs-etm.h | 12 +++ 2 files changed, 119 insertions(+), 19 deletions(-)

diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c index 911426721170..1fc597532c78 100644 --- a/tools/perf/arch/arm/util/cs-etm.c +++ b/tools/perf/arch/arm/util/cs-etm.c @@ -35,8 +35,100 @@ struct cs_etm_recording { size_t snapshot_size; }; +static const char *metadata_etmv3_ro[CS_ETM_PRIV_MAX] = {

• [CS_ETM_ETMCCER] = "mgmt/etmccer",
• [CS_ETM_ETMIDR] = "mgmt/etmidr",

+};

+static const char *metadata_etmv4_ro[CS_ETMV4_PRIV_MAX] = {

• [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",

+};

static bool cs_etm_is_etmv4(struct auxtrace_record *itr, int cpu); +static int cs_etm_set_context_id(struct auxtrace_record *itr,

• 		 struct perf_evsel *evsel, int cpu)
  

+{

• struct cs_etm_recording *ptr;
• struct perf_pmu *cs_etm_pmu;
• char path[PATH_MAX];
• int err = -EINVAL;
• u32 val;
• ptr = container_of(itr, struct cs_etm_recording, itr);
• cs_etm_pmu = ptr->cs_etm_pmu;
• if (!cs_etm_is_etmv4(itr, cpu))

• goto out;
  

• /* Get a handle on TRCIRD2 */
• snprintf(path, PATH_MAX, "cpu%d/%s",

•  cpu, metadata_etmv4_ro[CS_ETMV4_TRCIDR2]);
  

• err = perf_pmu__scan_file(cs_etm_pmu, path, "%x", &val);
• /* There was a problem reading the file, bailing out */
• if (err != 1) {

• pr_err("%s: can't read file %s\n",
  

•        CORESIGHT_ETM_PMU_NAME, path);
  

• goto out;
  

• }
• /*

• * TRCIDR2.CIDSIZE, bit [9-5], indicates whether contextID tracing
  

• * is supported:
  

• *  0b00000 Context ID tracing is not supported.
  

• *  0b00100 Maximum of 32-bit Context ID size.
  

• *  All other values are reserved.
  

• */
  

• val = BMVAL(val, 5, 9);
• if (!val || val != 0x4) {

• err = -EINVAL;
  

• goto out;
  

• }
• /* All good, let the kernel know */
• evsel->attr.config |= (1 << ETM_OPT_CTXTID);
• err = 0;

+out:

• return err;

+}

+static int cs_etm_set_option(struct auxtrace_record *itr,

• 	     struct perf_evsel *evsel, u32 option)
  

+{

• int i, err = -EINVAL;
• struct cpu_map *event_cpus = evsel->evlist->cpus;
• struct cpu_map *online_cpus = cpu_map__new(NULL);
• /* Set option of each CPU we have */
• for (i = 0; i < cpu__max_cpu(); i++) {

• if (!cpu_map__has(event_cpus, i) ||
  

•     !cpu_map__has(online_cpus, i))
  

• 	continue;
  

• switch (option) {
  

• case ETM_OPT_CTXTID:
  

• 	err = cs_etm_set_context_id(itr, evsel, i);
  

• 	if (err)
  

• 		goto out;
  

• 	break;
  

• default:
  

• 	break;
  

• }
  

• }
• err = 0;

Nitpick: maybe we should remove the sentence 'err = 0' so that for any unknown option, we can resturn '-EINVAL'.

I think what is really missing here is a 'goto' statement in the default clause. Well spotted.

Mathieu

...

+out:

• cpu_map__put(online_cpus);
• return err;

+}

static int cs_etm_parse_snapshot_options(struct auxtrace_record *itr, struct record_opts *opts, const char *str) @@ -105,8 +197,9 @@ static int cs_etm_recording_options(struct auxtrace_record *itr, container_of(itr, struct cs_etm_recording, itr); struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu; struct perf_evsel *evsel, *cs_etm_evsel = NULL;

• const struct cpu_map *cpus = evlist->cpus;

• struct cpu_map *cpus = evlist->cpus; bool privileged = (geteuid() == 0 || perf_event_paranoid() < 0);
• int err = 0;

ptr->evlist = evlist; ptr->snapshot_mode = opts->auxtrace_snapshot_mode; @@ -241,19 +334,24 @@ static int cs_etm_recording_options(struct auxtrace_record *itr, /* * In the case of per-cpu mmaps, we need the CPU on the

• * AUX event.
  

• * AUX event.  We also need the contextID in order to be notified
  

• * when a context switch happened.
  

  */

• if (!cpu_map__empty(cpus))

• if (!cpu_map__empty(cpus)) { perf_evsel__set_sample_bit(cs_etm_evsel, CPU);

• err = cs_etm_set_option(itr, cs_etm_evsel, ETM_OPT_CTXTID);
  

• if (err)
  

• 	goto out;
  

• }
• /* Add dummy event to keep tracking */ if (opts->full_auxtrace) { struct perf_evsel *tracking_evsel;

• int err;
  

err = parse_events(evlist, "dummy:u", NULL); if (err)

• 	return err;
  

• 	goto out;
  

tracking_evsel = perf_evlist__last(evlist); perf_evlist__set_tracking_event(evlist, tracking_evsel); @@ -266,7 +364,8 @@ static int cs_etm_recording_options(struct auxtrace_record *itr, perf_evsel__set_sample_bit(tracking_evsel, TIME); }

• return 0;

+out:

• return err;

} static u64 cs_etm_get_config(struct auxtrace_record *itr) @@ -314,6 +413,8 @@ static u64 cs_etmv4_get_config(struct auxtrace_record *itr) config_opts = cs_etm_get_config(itr); if (config_opts & BIT(ETM_OPT_CYCACC)) config |= BIT(ETM4_CFG_BIT_CYCACC);

• if (config_opts & BIT(ETM_OPT_CTXTID))

• config |= BIT(ETM4_CFG_BIT_CTXTID);
  

  if (config_opts & BIT(ETM_OPT_TS)) config |= BIT(ETM4_CFG_BIT_TS); if (config_opts & BIT(ETM_OPT_RETSTK))

@@ -363,19 +464,6 @@ cs_etm_info_priv_size(struct auxtrace_record *itr __maybe_unused, (etmv3 * CS_ETMV3_PRIV_SIZE)); } -static const char *metadata_etmv3_ro[CS_ETM_PRIV_MAX] = {

• [CS_ETM_ETMCCER] = "mgmt/etmccer",
• [CS_ETM_ETMIDR] = "mgmt/etmidr",

-};

-static const char *metadata_etmv4_ro[CS_ETMV4_PRIV_MAX] = {

• [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",

-};

static bool cs_etm_is_etmv4(struct auxtrace_record *itr, int cpu) { bool ret = false; diff --git a/tools/perf/util/cs-etm.h b/tools/perf/util/cs-etm.h index 0e97c196147a..826c9eedaf5c 100644 --- a/tools/perf/util/cs-etm.h +++ b/tools/perf/util/cs-etm.h @@ -103,6 +103,18 @@ struct intlist *traceid_list; #define KiB(x) ((x) * 1024) #define MiB(x) ((x) * 1024 * 1024) +/*

• • Create a contiguous bitmask starting at bit position @l and ending at
• • position @h. For example
• • GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
• • Carbon copy of implementation found in $KERNEL/include/linux/bitops.h
• */

+#define GENMASK(h, l) \

• (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))

+#define BMVAL(val, lsb, msb) ((val & GENMASK(msb, lsb)) >> lsb)

#define CS_ETM_HEADER_SIZE (CS_HEADER_VERSION_0_MAX * sizeof(u64))

#define __perf_cs_etmv3_magic 0x3030303030303030ULL

2.17.1