From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A48752BD5A2; Tue, 16 Dec 2025 12:18:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765887513; cv=none; b=HPopbtS188U4b+SRBvCgHRQHYlMOYIfIN9BXtfGd/G1WAeJw3waYiru524sYw131GldHDw2Ego2t957mp6JRPWQuvVXR03OKp3jUv/YDn4jtXdqZf3ASt06PcLmm3qThA2rv8MI5DYFyqTeqAByYthGjFCpIHfh0cPZZn/1EvaQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765887513; c=relaxed/simple; bh=gWAbfJRLVYOZZ7aXN0SrLb2OpIqPGW0FOsEOMHWwxMU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=op8fVmuVxClkP4jJFxidEsnxRShlNNZMwad1L8rw5rXdcsYDV7yHzQqRz7k/HhmShhQatX3HYYOrzHviXycQWJPw4GAai9tOjjsoxa2E1qslsqG+3NboBLS7j3INxzLk1aWMymLzocrLq8j22PQBQt92y92oZGmAD0j/TcE3V2E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=iyfMnNlv; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="iyfMnNlv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 13DFCC4CEF1; Tue, 16 Dec 2025 12:18:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1765887513; bh=gWAbfJRLVYOZZ7aXN0SrLb2OpIqPGW0FOsEOMHWwxMU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iyfMnNlvJjsORPiubbe2mVZ1lw+uOzOvtY1qF7ZcOIIBjZlU0MLUGapyRiejtROum /Dt9qSaX+b64KTgRvwA7o1pFWFIpFJYjYU55RS152UhaQUPEeJ9DJNDm6uPg3lqPyY nff1HRIRMfHM1tqyTbhCKsQQ5bO5LCT7ym+1qoVw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Mike Leach , James Clark , Leo Yan , Suzuki K Poulose , Sasha Levin Subject: [PATCH 6.18 254/614] coresight: etm3x: Always set tracers device mode on target CPU Date: Tue, 16 Dec 2025 12:10:21 +0100 Message-ID: <20251216111410.577733259@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20251216111401.280873349@linuxfoundation.org> References: <20251216111401.280873349@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Leo Yan [ Upstream commit ab3fde32afe6a77e5cc60f868e44e6e09424752b ] The ETMv3 driver shares the same issue as ETMv4 regarding race conditions when accessing the device mode. This commit applies the same fix: ensuring that the device mode is modified only by the target CPU to eliminate race conditions across CPUs. Fixes: 22fd532eaa0c ("coresight: etm3x: adding operation mode for etm_enable()") Reviewed-by: Mike Leach Tested-by: James Clark Signed-off-by: Leo Yan Signed-off-by: Suzuki K Poulose Link: https://lore.kernel.org/r/20251111-arm_coresight_power_management_fix-v6-3-f55553b6c8b3@arm.com Signed-off-by: Sasha Levin --- .../coresight/coresight-etm3x-core.c | 59 +++++++++++++------ 1 file changed, 40 insertions(+), 19 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c index 45630a1cd32fb..a5e809589d3e3 100644 --- a/drivers/hwtracing/coresight/coresight-etm3x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c @@ -439,13 +439,26 @@ struct etm_enable_arg { int rc; }; -static void etm_enable_hw_smp_call(void *info) +static void etm_enable_sysfs_smp_call(void *info) { struct etm_enable_arg *arg = info; + struct coresight_device *csdev; if (WARN_ON(!arg)) return; + + csdev = arg->drvdata->csdev; + if (!coresight_take_mode(csdev, CS_MODE_SYSFS)) { + /* Someone is already using the tracer */ + arg->rc = -EBUSY; + return; + } + arg->rc = etm_enable_hw(arg->drvdata); + + /* The tracer didn't start */ + if (arg->rc) + coresight_set_mode(csdev, CS_MODE_DISABLED); } static int etm_cpu_id(struct coresight_device *csdev) @@ -465,16 +478,26 @@ static int etm_enable_perf(struct coresight_device *csdev, struct coresight_path *path) { struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); + int ret; if (WARN_ON_ONCE(drvdata->cpu != smp_processor_id())) return -EINVAL; + if (!coresight_take_mode(csdev, CS_MODE_PERF)) + return -EBUSY; + /* Configure the tracer based on the session's specifics */ etm_parse_event_config(drvdata, event); drvdata->traceid = path->trace_id; /* And enable it */ - return etm_enable_hw(drvdata); + ret = etm_enable_hw(drvdata); + + /* Failed to start tracer; roll back to DISABLED mode */ + if (ret) + coresight_set_mode(csdev, CS_MODE_DISABLED); + + return ret; } static int etm_enable_sysfs(struct coresight_device *csdev, struct coresight_path *path) @@ -494,7 +517,7 @@ static int etm_enable_sysfs(struct coresight_device *csdev, struct coresight_pat if (cpu_online(drvdata->cpu)) { arg.drvdata = drvdata; ret = smp_call_function_single(drvdata->cpu, - etm_enable_hw_smp_call, &arg, 1); + etm_enable_sysfs_smp_call, &arg, 1); if (!ret) ret = arg.rc; if (!ret) @@ -517,12 +540,6 @@ static int etm_enable(struct coresight_device *csdev, struct perf_event *event, enum cs_mode mode, struct coresight_path *path) { int ret; - struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); - - if (!coresight_take_mode(csdev, mode)) { - /* Someone is already using the tracer */ - return -EBUSY; - } switch (mode) { case CS_MODE_SYSFS: @@ -535,17 +552,12 @@ static int etm_enable(struct coresight_device *csdev, struct perf_event *event, ret = -EINVAL; } - /* The tracer didn't start */ - if (ret) - coresight_set_mode(drvdata->csdev, CS_MODE_DISABLED); - return ret; } -static void etm_disable_hw(void *info) +static void etm_disable_hw(struct etm_drvdata *drvdata) { int i; - struct etm_drvdata *drvdata = info; struct etm_config *config = &drvdata->config; struct coresight_device *csdev = drvdata->csdev; @@ -567,6 +579,15 @@ static void etm_disable_hw(void *info) "cpu: %d disable smp call done\n", drvdata->cpu); } +static void etm_disable_sysfs_smp_call(void *info) +{ + struct etm_drvdata *drvdata = info; + + etm_disable_hw(drvdata); + + coresight_set_mode(drvdata->csdev, CS_MODE_DISABLED); +} + static void etm_disable_perf(struct coresight_device *csdev) { struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); @@ -588,6 +609,8 @@ static void etm_disable_perf(struct coresight_device *csdev) CS_LOCK(drvdata->csa.base); + coresight_set_mode(drvdata->csdev, CS_MODE_DISABLED); + /* * perf will release trace ids when _free_aux() * is called at the end of the session @@ -612,7 +635,8 @@ static void etm_disable_sysfs(struct coresight_device *csdev) * Executing etm_disable_hw on the cpu whose ETM is being disabled * ensures that register writes occur when cpu is powered. */ - smp_call_function_single(drvdata->cpu, etm_disable_hw, drvdata, 1); + smp_call_function_single(drvdata->cpu, etm_disable_sysfs_smp_call, + drvdata, 1); spin_unlock(&drvdata->spinlock); cpus_read_unlock(); @@ -652,9 +676,6 @@ static void etm_disable(struct coresight_device *csdev, WARN_ON_ONCE(mode); return; } - - if (mode) - coresight_set_mode(csdev, CS_MODE_DISABLED); } static const struct coresight_ops_source etm_source_ops = { -- 2.51.0