From patchwork Fri Sep 15 09:36:47 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anshuman Khandual X-Patchwork-Id: 13386718 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4680FEE644B for ; Fri, 15 Sep 2023 09:37:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=tv4pNlDaxsL0a/YjMnTbAhNaFF2U6/Gz4aNKGwypKIk=; b=e+MFONWQg4g9Ex EEJ30ykizI2398RwqPAPysPO+9k+a6hrbriGC0uAj1DZf3DnVJfjI7df0KwodvL0Hq9LqeOO7AT4Z rju7ULhyNaYJFasWNlOXPkk29/WJPis7YzupOEGxYf76vOPHuzkVBeHd7PVnHx92H9v6ssEPpzZD8 m7fPdBG2hP80TC52dTt64/Zh8OvU/qYrh0fbeSh7ryFLPFw1dxeqbxQt22ZeQJykXt3CIW5OaiJW2 TYE++iTiFPb4Xan3dVoYoHQf95sGV8XYjl8kFmJlK/HkruS1KWdibpjxwmfUcDQ0shrTN2/b37vaz I1zQ4ORi1iXfgWCv++7g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qh5GI-00AIB4-2g; Fri, 15 Sep 2023 09:37:18 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qh5GD-00AI8t-31 for linux-arm-kernel@lists.infradead.org; Fri, 15 Sep 2023 09:37:15 +0000 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 3F24AC15; Fri, 15 Sep 2023 02:37:48 -0700 (PDT) Received: from a077893.arm.com (unknown [10.163.62.147]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 5A0243F67D; Fri, 15 Sep 2023 02:37:07 -0700 (PDT) From: Anshuman Khandual To: linux-arm-kernel@lists.infradead.org, suzuki.poulose@arm.com Cc: Anshuman Khandual , Catalin Marinas , Will Deacon , Mike Leach , James Clark , Leo Yan , Jonathan Corbet , linux-doc@vger.kernel.org, coresight@lists.linaro.org, linux-kernel@vger.kernel.org Subject: [PATCH V5 - RESEND 1/3] coresight: etm: Override TRCIDR3.CCITMIN on errata affected cpus Date: Fri, 15 Sep 2023 15:06:47 +0530 Message-Id: <20230915093649.435163-2-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230915093649.435163-1-anshuman.khandual@arm.com> References: <20230915093649.435163-1-anshuman.khandual@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230915_023714_063511_B1EF3727 X-CRM114-Status: GOOD ( 15.44 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org This work arounds errata 1490853 on Cortex-A76, and Neoverse-N1, errata 1491015 on Cortex-A77, errata 1502854 on Cortex-X1, and errata 1619801 on Neoverse-V1, based affected cpus, where software read for TRCIDR3.CCITMIN field in ETM gets an wrong value. If software uses the value returned by the TRCIDR3.CCITMIN register field, then it will limit the range which could be used for programming the ETM. In reality, the ETM could be programmed with a much smaller value than what is indicated by the TRCIDR3.CCITMIN field and still function correctly. If software reads the TRCIDR3.CCITMIN register field, corresponding to the instruction trace counting minimum threshold, observe the value 0x100 or a minimum cycle count threshold of 256. The correct value should be 0x4 or a minimum cycle count threshold of 4. This work arounds the problem via storing 4 in drvdata->ccitmin on affected systems where the TRCIDR3.CCITMIN has been 256, thus preserving cycle count threshold granularity. These errata information has been updated in arch/arm64/silicon-errata.rst, but without their corresponding configs because these have been implemented directly in the driver. Cc: Catalin Marinas Cc: Will Deacon Cc: Suzuki K Poulose Cc: Mike Leach Cc: James Clark Cc: Jonathan Corbet Cc: linux-doc@vger.kernel.org Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual --- Documentation/arch/arm64/silicon-errata.rst | 10 ++++++ .../coresight/coresight-etm4x-core.c | 36 +++++++++++++++++++ 2 files changed, 46 insertions(+) diff --git a/Documentation/arch/arm64/silicon-errata.rst b/Documentation/arch/arm64/silicon-errata.rst index e96f057ea2a0..8f1be5da68b7 100644 --- a/Documentation/arch/arm64/silicon-errata.rst +++ b/Documentation/arch/arm64/silicon-errata.rst @@ -115,6 +115,10 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A76 | #1463225 | ARM64_ERRATUM_1463225 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-A76 | #1490853 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-A77 | #1491015 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A77 | #1508412 | ARM64_ERRATUM_1508412 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A710 | #2119858 | ARM64_ERRATUM_2119858 | @@ -125,6 +129,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A715 | #2645198 | ARM64_ERRATUM_2645198 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-X1 | #1502854 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-X2 | #2119858 | ARM64_ERRATUM_2119858 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-X2 | #2224489 | ARM64_ERRATUM_2224489 | @@ -133,6 +139,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N1 | #1349291 | N/A | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Neoverse-N1 | #1490853 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N1 | #1542419 | ARM64_ERRATUM_1542419 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N2 | #2139208 | ARM64_ERRATUM_2139208 | @@ -141,6 +149,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N2 | #2253138 | ARM64_ERRATUM_2253138 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Neoverse-V1 | #1619801 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | MMU-500 | #841119,826419 | N/A | +----------------+-----------------+-----------------+-----------------------------+ | ARM | MMU-600 | #1076982,1209401| N/A | diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 77b0271ce6eb..c01455bb1caf 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -1150,6 +1150,39 @@ static void cpu_detect_trace_filtering(struct etmv4_drvdata *drvdata) drvdata->trfcr = trfcr; } +/* + * The following errata on applicable cpu ranges, affect the CCITMIN filed + * in TCRIDR3 register. Software read for the field returns 0x100 limiting + * the cycle threshold granularity, whereas the right value should have + * been 0x4, which is well supported in the hardware. + */ +static struct midr_range etm_wrong_ccitmin_cpus[] = { + /* Erratum #1490853 - Cortex-A76 */ + MIDR_RANGE(MIDR_CORTEX_A76, 0, 0, 4, 0), + /* Erratum #1490853 - Neoverse-N1 */ + MIDR_RANGE(MIDR_NEOVERSE_N1, 0, 0, 4, 0), + /* Erratum #1491015 - Cortex-A77 */ + MIDR_RANGE(MIDR_CORTEX_A77, 0, 0, 1, 0), + /* Erratum #1502854 - Cortex-X1 */ + MIDR_REV(MIDR_CORTEX_X1, 0, 0), + /* Erratum #1619801 - Neoverse-V1 */ + MIDR_REV(MIDR_NEOVERSE_V1, 0, 0), + {}, +}; + +static bool etm4_core_reads_wrong_ccitmin(struct etmv4_drvdata *drvdata) +{ + /* + * Erratum affected cpus will read 256 as the minimum + * instruction trace cycle counting threshold whereas + * the correct value should be 4 instead. Override the + * recorded value for 'drvdata->ccitmin' to workaround + * this problem. + */ + return is_midr_in_range_list(read_cpuid_id(), etm_wrong_ccitmin_cpus) && + (drvdata->ccitmin == 256); +} + static void etm4_init_arch_data(void *info) { u32 etmidr0; @@ -1214,6 +1247,9 @@ static void etm4_init_arch_data(void *info) etmidr3 = etm4x_relaxed_read32(csa, TRCIDR3); /* CCITMIN, bits[11:0] minimum threshold value that can be programmed */ drvdata->ccitmin = FIELD_GET(TRCIDR3_CCITMIN_MASK, etmidr3); + if (etm4_core_reads_wrong_ccitmin(drvdata)) + drvdata->ccitmin = 4; + /* EXLEVEL_S, bits[19:16] Secure state instruction tracing */ drvdata->s_ex_level = FIELD_GET(TRCIDR3_EXLEVEL_S_MASK, etmidr3); drvdata->config.s_ex_level = drvdata->s_ex_level; From patchwork Fri Sep 15 09:36:48 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anshuman Khandual X-Patchwork-Id: 13386719 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 06B53EE644B for ; Fri, 15 Sep 2023 09:37:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=n9i2M84M9vFqV/TYpgCS1j9M5uR1HJz4EI1U+jf61sA=; b=NC822n3HZ4s5cj LgkSfIP7DERLue5hi7M/Y9ZBztN/eRG240Wa1DQbwM8aEytg5B/tGC6WPM6U0X6ITqsQ2cuQ5iAnq RMpVwUjcYwVFCGWGIcdBjcoIUCDvClhUSOwlm2khtAAWfuAHYZpjrFrV5YH++xWPqxFRGmo6SYq0R 6bnsfkXVIcxPTzPohyTXuQLUiBd1xYDKcRvGx2fPEB+c4uaFBHLlVIslK0D+3SZdOoFVqlOWKFncB nqQZSEEW+gA5mlCF0kXvWqYDOcEC1CWFf11grVUdK2G/++4Klaedk846xqjWRunj/TEClonpABsnc sL3mvFsMekUiAk/egkiw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qh5GN-00AICs-1Y; Fri, 15 Sep 2023 09:37:23 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qh5GI-00AIAI-1H for linux-arm-kernel@lists.infradead.org; Fri, 15 Sep 2023 09:37:20 +0000 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 593541FB; Fri, 15 Sep 2023 02:37:52 -0700 (PDT) Received: from a077893.arm.com (unknown [10.163.62.147]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 7B65B3F67D; Fri, 15 Sep 2023 02:37:11 -0700 (PDT) From: Anshuman Khandual To: linux-arm-kernel@lists.infradead.org, suzuki.poulose@arm.com Cc: Anshuman Khandual , Catalin Marinas , Will Deacon , Mike Leach , James Clark , Leo Yan , Jonathan Corbet , linux-doc@vger.kernel.org, coresight@lists.linaro.org, linux-kernel@vger.kernel.org Subject: [PATCH V5 - RESEND 2/3] coresight: etm: Make cycle count threshold user configurable Date: Fri, 15 Sep 2023 15:06:48 +0530 Message-Id: <20230915093649.435163-3-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230915093649.435163-1-anshuman.khandual@arm.com> References: <20230915093649.435163-1-anshuman.khandual@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230915_023718_533609_321F21BD X-CRM114-Status: GOOD ( 14.10 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 Reviewed-by: Mike Leach Signed-off-by: Anshuman Khandual Reviewed-by: Mike Leach --- drivers/hwtracing/coresight/coresight-etm-perf.c | 2 ++ drivers/hwtracing/coresight/coresight-etm4x-core.c | 9 +++++++-- 2 files changed, 9 insertions(+), 2 deletions(-) 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 c01455bb1caf..044aed25979b 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 +667,12 @@ 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) + cc_threshold = ETM_CYC_THRESHOLD_DEFAULT; + if (cc_threshold < drvdata->ccitmin) + cc_threshold = drvdata->ccitmin; + config->ccctlr = cc_threshold; } if (attr->config & BIT(ETM_OPT_TS)) { /* From patchwork Fri Sep 15 09:36:49 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anshuman Khandual X-Patchwork-Id: 13386720 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B4167EE644B for ; Fri, 15 Sep 2023 09:37:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=JvoR8OiYRzq4J2A6VDj2Dn9SMPoB/v2sKHjPKltFwLQ=; b=0fNTVM85lIE4FW 0LSRS4U/fu/VD9kNgQ0nbXVo2oftYwlwc33UQMBzBbYZeS+ihy6HSTD+AqjWDc0WxhQt+VhZSyJkJ WHoh/r/2P4WEgWCxB1zCBwjSUuz+Jq+Atv25V08GosF5EW4QPJkhaj4lcmvYpaFoSbxDDvMibBfA4 RbY0i5Gf49ff0cek9J+U2CJTVCgUxW/qZb4tfvM+INAqThG7H+rAm1mda2ttqsvKw9X1oeXNsxupn 3++nz7mPM3+3nWnph+8pTEJ+A8KOneIa1Dv5RIbrLd7xk8fXLZcuQLW1A5jbocaWYups77LLZ5Cwp 1XL0MvxrYT6qNJng/GqQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qh5GO-00AIDC-02; Fri, 15 Sep 2023 09:37:24 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qh5GK-00AIBa-2N for linux-arm-kernel@lists.infradead.org; Fri, 15 Sep 2023 09:37:22 +0000 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 0EBCEC15; Fri, 15 Sep 2023 02:37:57 -0700 (PDT) Received: from a077893.arm.com (unknown [10.163.62.147]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 980DF3F67D; Fri, 15 Sep 2023 02:37:15 -0700 (PDT) From: Anshuman Khandual To: linux-arm-kernel@lists.infradead.org, suzuki.poulose@arm.com Cc: Anshuman Khandual , Catalin Marinas , Will Deacon , Mike Leach , James Clark , Leo Yan , Jonathan Corbet , linux-doc@vger.kernel.org, coresight@lists.linaro.org, linux-kernel@vger.kernel.org Subject: [PATCH V5 - RESEND 3/3] Documentation: coresight: Add cc_threshold tunable Date: Fri, 15 Sep 2023 15:06:49 +0530 Message-Id: <20230915093649.435163-4-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230915093649.435163-1-anshuman.khandual@arm.com> References: <20230915093649.435163-1-anshuman.khandual@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230915_023720_818059_952515A6 X-CRM114-Status: GOOD ( 10.31 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org This updates config option to include 'cc_threshold' tunable value. Cc: Suzuki K Poulose Cc: Mike Leach Cc: James Clark Cc: Jonathan Corbet Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Reviewed by: Mike Leach Signed-off-by: Anshuman Khandual --- Documentation/trace/coresight/coresight.rst | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/Documentation/trace/coresight/coresight.rst b/Documentation/trace/coresight/coresight.rst index 4a71ea6cb390..ce55adb80b82 100644 --- a/Documentation/trace/coresight/coresight.rst +++ b/Documentation/trace/coresight/coresight.rst @@ -624,6 +624,10 @@ 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. If nothing is provided here or the provided value is 0, then the + default value i.e 0x100 will be used. If provided value is less than minimum cycles threshold + value, as indicated via TRCIDR3.CCITMIN, then the minimum value will be used instead. How to use the STM module -------------------------