From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 3642A3624C3 for ; Fri, 2 Oct 2026 19:03:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790967821; cv=none; b=pDhupDdTW+PMjv11mtB9uXzzOFoUBXGEAzaiqRTmfXB4oydtU8vGONGJQk9IKJ6iLwivDBh2cLGmhRIIHpdqbBX6DkhCab1D03pF6pbS9MkuqlebgQ/2m8/0/xvuMpHiQNoEoHF18EXNYPD5VD7xQKirlTB9q5r+stfBMtXWWHs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790967821; c=relaxed/simple; bh=/LTIVchcSYeV2GdWMsw9q/5+SrFXYHpc2drQmo5k3iU=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=LffXYC2I6dx8MDekmUrTN/E8pFedVWLgJSLoCqkx/rtTl/NrYPe3e1WbQp/4f28UylagqvRxzQPNmFqLcPuYzp22DZWvlQ7UQ/lJxoxgfJAwa+IGhpqdnbdYXT69TpUoiRPoVDgTikGRS9eW3QSfPSljY8bbDQU+NS4xvoEFuaA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=aT0sNsfv; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="aT0sNsfv" 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 2522F143D; Fri, 2 Oct 2026 12:03:36 -0700 (PDT) Received: from e129823.arm.com (e129823.arm.com [10.2.213.3]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 85A4E3F85F; Fri, 2 Oct 2026 12:03:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1790967819; bh=/LTIVchcSYeV2GdWMsw9q/5+SrFXYHpc2drQmo5k3iU=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=aT0sNsfviVxPNATmbhcyBxXAOVAx3R9gnCgUfw66GVkFS4ppj8V7k0S8+8hhcKOOf dTL5OLCcj0b4IHf+9RyUdpq+NME1uqatlyS03awqxcA0R7aQ+gnZcXmYGFRKcAn5dW sN4h0gTq3BLABYdUbSF2pVhorYx+7FKOrW7w9sbs= From: Yeoreum Yun Date: Fri, 02 Oct 2026 20:03:22 +0100 Subject: [PATCH v13 01/14] coresight: etm4x: read-back TRCSEQSTR at disabling and prohibit modifying seq_state while enabling. Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261002-separate_etm_cfg_v2-v13-1-fe429d8d96fb@arm.com> References: <20261002-separate_etm_cfg_v2-v13-0-fe429d8d96fb@arm.com> In-Reply-To: <20261002-separate_etm_cfg_v2-v13-0-fe429d8d96fb@arm.com> To: Mike Leach , James Clark , Leo Yan , Greg Kroah-Hartman , Mathieu Poirier , coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev Cc: Suzuki K Poulose , Alexander Shishkin , Sebastian Andrzej Siewior , Clark Williams , Steven Rostedt , Yeoreum Yun X-Mailer: b4 0.13.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1970; i=yeoreum.yun@arm.com; h=from:subject:message-id; bh=/LTIVchcSYeV2GdWMsw9q/5+SrFXYHpc2drQmo5k3iU=; b=owEB7QES/pANAwAKAW3Vw9FaxTEzAcsmYgBqv///9VUKc6rivLVuGZ3pF7zctdNW30JEAt83a TTuwEFcbiqJAbMEAAEKAB0WIQQtg+CS3QUzuFh1pJ1t1cPRWsUxMwUCar///wAKCRBt1cPRWsUx MzSlC/9lcq/dhBMe/2rI3OVtkt/qBuf/DqV6YdDCvTGe3Kb8T1HYlI8y2YhsPFmG4bSCXBEuma4 8D2zgZfmhhO1VAMU22lvoT1UzcyuyeBDY8WJIobZjV/JhBlEM8Cjrs/TA21YPlYdlwPlWDHVz69 PMnPG3umS+5y6U7Ws2b332aJBl9dMKSIbAgu1F+d4u0oqqWw9At+WErwXLag2PRUeHrfM6t5BeY 4jhwCPgEvmBAQth1GV8dWhZEQ8gx87RtToOEqwNpm+aauT/XO6e5iKoC8NaQ+bX9hPTnvbeR+Kx 1RSfhWWyAdbMlT99q921rLzho9EiuB+RVvcEz/s3a1vFaOjVDdH63hcCRMOdJJ++QWg6fC9nT7p LUnaiGFSOA1dtNXsLjFoFSdJbRH5FVz3MiILfMKzJMlyoG0GE6WH1dexnD44tL2AU0T0AWKiQnR VJ3w39OchpZnR/eIKP8MYI9c7bl8FC6Oii7rvzW1d56+A7GPzdjpQ1aV5r37Zpmh5teo4= X-Developer-Key: i=yeoreum.yun@arm.com; a=openpgp; fpr=2D83E092DD0533B85875A49D6DD5C3D15AC53133 TRCSEQSTR can be changed by the ETM while a session is active. Its value therefore needs to be preserved when a sysfs session is disabled so that users can read the current sequence state after the session ends. This means that any changes made to TRCSEQSTR while the sysfs-session is active would be lost when the session is disabled. Copy the TRCSEQSTR value when disabling a sysfs session, and prohibit modifying seq_state while the session is active. Suggested-by: Mike Leach Reviewed-by: Mike Leach Signed-off-by: Yeoreum Yun --- drivers/hwtracing/coresight/coresight-etm4x-core.c | 4 ++++ drivers/hwtracing/coresight/coresight-etm4x-sysfs.c | 2 ++ 2 files changed, 6 insertions(+) diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 2247ad55d444..9ca03a5913a3 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -1073,6 +1073,10 @@ static void etm4_disable_hw(struct etmv4_drvdata *drvdata) etm4x_relaxed_read32(csa, TRCCNTVRn(i)); } + /* read back the sequence state */ + if (drvdata->nrseqstate) + config->seq_state = etm4x_relaxed_read32(csa, TRCSEQSTR); + coresight_disclaim_device_unlocked(csdev); etm4_cs_lock(drvdata, csa); diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c index cc6cdd3ae29d..2c72ea831fe6 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c @@ -1435,6 +1435,8 @@ static ssize_t seq_state_store(struct device *dev, if (kstrtoul(buf, 16, &val)) return -EINVAL; + if (IS_ERR_OR_NULL(drvdata) || coresight_get_mode(drvdata->csdev)) + return -EBUSY; if (val >= drvdata->nrseqstate) return -EINVAL; -- 2.43.0