linux-kernel - [PATCH v1 RESEND 2/2] perf cs-etm: Respect timestamp option

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20231014074159.1667880-3-leo.yan@linaro.org>
Date:   Sat, 14 Oct 2023 15:41:59 +0800
From:   Leo Yan <leo.yan@...aro.org>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        James Clark <james.clark@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Mike Leach <mike.leach@...aro.org>
Cc:     John Garry <john.g.garry@...cle.com>,
        Will Deacon <will@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Ian Rogers <irogers@...gle.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org,
        linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
        Leo Yan <leo.yan@...aro.org>
Subject: [PATCH v1 RESEND 2/2] perf cs-etm: Respect timestamp option

When users pass the option '--timestamp' or '-T' in the record command,
all events will set the PERF_SAMPLE_TIME bit in the attribution.  In
this case, the AUX event will record the kernel timestamp, but it
doesn't mean Arm CoreSight enables timestamp packets in its hardware
tracing.

If the option '--timestamp' or '-T' is set, this patch always enables
Arm CoreSight timestamp, as a result, the bit 28 in event's config is to
be set.

Before:

  # perf record -e cs_etm// --per-thread --timestamp -- ls
  # perf script --header-only
  ...
  # event : name = cs_etm//, , id = { 69 }, type = 12, size = 136,
  config = 0, { sample_period, sample_freq } = 1,
  sample_type = IP|TID|TIME|CPU|IDENTIFIER, read_format = ID|LOST,
  disabled = 1, enable_on_exec = 1, sample_id_all = 1, exclude_guest = 1
  ...

After:

  # perf record -e cs_etm// --per-thread --timestamp -- ls
  # perf script --header-only
  ...
  # event : name = cs_etm//, , id = { 49 }, type = 12, size = 136,
  config = 0x10000000, { sample_period, sample_freq } = 1,
  sample_type = IP|TID|TIME|CPU|IDENTIFIER, read_format = ID|LOST,
  disabled = 1, enable_on_exec = 1, sample_id_all = 1, exclude_guest = 1
  ...

Signed-off-by: Leo Yan <leo.yan@...aro.org>
Reviewed-by: James Clark <james.clark@....com>
---
 tools/perf/arch/arm/util/cs-etm.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c
index cf9ef9ba800b..58c506e9788d 100644
--- a/tools/perf/arch/arm/util/cs-etm.c
+++ b/tools/perf/arch/arm/util/cs-etm.c
@@ -442,6 +442,15 @@ static int cs_etm_recording_options(struct auxtrace_record *itr,
 					   "contextid", 1);
 	}
 
+	/*
+	 * When the option '--timestamp' or '-T' is enabled, the PERF_SAMPLE_TIME
+	 * bit is set for all events.  In this case, always enable Arm CoreSight
+	 * timestamp tracing.
+	 */
+	if (opts->sample_time_set)
+		evsel__set_config_if_unset(cs_etm_pmu, cs_etm_evsel,
+					   "timestamp", 1);
+
 	/* Add dummy event to keep tracking */
 	err = parse_event(evlist, "dummy:u");
 	if (err)
-- 
2.34.1