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[2620:137:e000::1:20]) by mx.google.com with ESMTP id a5-20020a170902710500b001b5fc11ea09si7575139pll.94.2023.08.08.11.21.56; Tue, 08 Aug 2023 11:22:09 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=arm.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233433AbjHHSDM (ORCPT + 99 others); Tue, 8 Aug 2023 14:03:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41384 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229643AbjHHSDJ (ORCPT ); Tue, 8 Aug 2023 14:03:09 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 9C2E43CD27; Tue, 8 Aug 2023 09:41:48 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id F1331D75; Tue, 8 Aug 2023 00:46:25 -0700 (PDT) Received: from a077893.blr.arm.com (unknown [10.162.40.16]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id D96723F6C4; Tue, 8 Aug 2023 00:45:39 -0700 (PDT) From: Anshuman Khandual To: linux-arm-kernel@lists.infradead.org Cc: Al.Grant@arm.com, Anshuman Khandual , Suzuki K Poulose , Mike Leach , James Clark , Leo Yan , coresight@lists.linaro.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] coresight: etm: Make cycle count threshold user configurable Date: Tue, 8 Aug 2023 13:15:33 +0530 Message-Id: <20230808074533.380537-1-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1773683792090069230 X-GMAIL-MSGID: 1773686153661202675 Cycle counting is enabled, when requested and supported but with a default threshold value ETM_CYC_THRESHOLD_DEFAULT i.e 0x100 getting into TRCCCCTLR, representing the minimum interval between cycle count trace packets. This makes cycle threshold user configurable, from the user space via perf event attributes. Although it falls back using ETM_CYC_THRESHOLD_DEFAULT, in case no explicit request. As expected it creates a sysfs file as well. /sys/bus/event_source/devices/cs_etm/format/cc_threshold New 'cc_threshold' uses 'event->attr.config3' as no more space is available in 'event->attr.config1' or 'event->attr.config2'. Cc: Suzuki K Poulose Cc: Mike Leach Cc: James Clark Cc: Leo Yan Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual --- Changes in V2: - s/treshhold/threshhold Changes in V1: https://lore.kernel.org/all/20230804044720.1478900-1-anshuman.khandual@arm.com/ Documentation/trace/coresight/coresight.rst | 2 ++ drivers/hwtracing/coresight/coresight-etm-perf.c | 2 ++ drivers/hwtracing/coresight/coresight-etm4x-core.c | 12 ++++++++++-- 3 files changed, 14 insertions(+), 2 deletions(-) diff --git a/Documentation/trace/coresight/coresight.rst b/Documentation/trace/coresight/coresight.rst index 4a71ea6cb390..a698b07206b5 100644 --- a/Documentation/trace/coresight/coresight.rst +++ b/Documentation/trace/coresight/coresight.rst @@ -624,6 +624,8 @@ They are also listed in the folder /sys/bus/event_source/devices/cs_etm/format/ * - timestamp - Session local version of the system wide setting: :ref:`ETMv4_MODE_TIMESTAMP ` + * - cc_threshold + - Cycle count threshold value How to use the STM module ------------------------- diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c index 5ca6278baff4..09f75dffae60 100644 --- a/drivers/hwtracing/coresight/coresight-etm-perf.c +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c @@ -68,6 +68,7 @@ PMU_FORMAT_ATTR(preset, "config:0-3"); PMU_FORMAT_ATTR(sinkid, "config2:0-31"); /* config ID - set if a system configuration is selected */ PMU_FORMAT_ATTR(configid, "config2:32-63"); +PMU_FORMAT_ATTR(cc_threshold, "config3:0-11"); /* @@ -101,6 +102,7 @@ static struct attribute *etm_config_formats_attr[] = { &format_attr_preset.attr, &format_attr_configid.attr, &format_attr_branch_broadcast.attr, + &format_attr_cc_threshold.attr, NULL, }; diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 9d186af81ea0..a353c0784bab 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -644,7 +644,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev, struct etmv4_config *config = &drvdata->config; struct perf_event_attr *attr = &event->attr; unsigned long cfg_hash; - int preset; + int preset, cc_threshold; /* Clear configuration from previous run */ memset(config, 0, sizeof(struct etmv4_config)); @@ -667,7 +667,15 @@ static int etm4_parse_event_config(struct coresight_device *csdev, if (attr->config & BIT(ETM_OPT_CYCACC)) { config->cfg |= TRCCONFIGR_CCI; /* TRM: Must program this for cycacc to work */ - config->ccctlr = ETM_CYC_THRESHOLD_DEFAULT; + cc_threshold = attr->config3 & ETM_CYC_THRESHOLD_MASK; + if (cc_threshold) { + if (cc_threshold < drvdata->ccitmin) + config->ccctlr = drvdata->ccitmin; + else + config->ccctlr = cc_threshold; + } else { + config->ccctlr = ETM_CYC_THRESHOLD_DEFAULT; + } } if (attr->config & BIT(ETM_OPT_TS)) { /*