From mboxrd@z Thu Jan 1 00:00:00 1970 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1E8A5C4332F for ; Tue, 8 Nov 2022 22:28:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230329AbiKHW2q (ORCPT ); Tue, 8 Nov 2022 17:28:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55860 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230222AbiKHW2Z (ORCPT ); Tue, 8 Nov 2022 17:28:25 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 97F3668ADB; Tue, 8 Nov 2022 14:25:04 -0800 (PST) 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 D57701FB; Tue, 8 Nov 2022 14:24:37 -0800 (PST) Received: from [10.57.68.207] (unknown [10.57.68.207]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0CC4E3F73D; Tue, 8 Nov 2022 14:24:29 -0800 (PST) Message-ID: Date: Tue, 8 Nov 2022 22:24:28 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.4.1 Subject: Re: [PATCH v5 05/14] coresight: etm4x: Update ETM4 driver to use Trace ID API To: Mike Leach , coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: mathieu.poirier@linaro.org, peterz@infradead.org, mingo@redhat.com, acme@kernel.org, linux-perf-users@vger.kernel.org, leo.yan@linaro.org, quic_jinlmao@quicinc.com References: <20221101163103.17921-1-mike.leach@linaro.org> <20221101163103.17921-6-mike.leach@linaro.org> From: Suzuki K Poulose In-Reply-To: <20221101163103.17921-6-mike.leach@linaro.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/11/2022 16:30, Mike Leach wrote: > The trace ID API is now used to allocate trace IDs for ETM4.x / ETE > devices. > > For perf sessions, these will be allocated on enable, and released on > disable. > > For sysfs sessions, these will be allocated on enable, but only released > on reset. This allows the sysfs session to interrogate the Trace ID used > after the session is over - maintaining functional consistency with the > previous allocation scheme. > > The trace ID will also be allocated on read of the mgmt/trctraceid file. > This ensures that if perf or sysfs read this before enabling trace, the > value will be the one used for the trace session. > > Trace ID initialisation is removed from the _probe() function. > > Signed-off-by: Mike Leach > --- > .../coresight/coresight-etm4x-core.c | 70 +++++++++++++++++-- > .../coresight/coresight-etm4x-sysfs.c | 27 ++++++- > drivers/hwtracing/coresight/coresight-etm4x.h | 3 + > 3 files changed, 90 insertions(+), 10 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c > index 80fefaba58ee..0e361d35c611 100644 > --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c > +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c > @@ -42,6 +42,7 @@ > #include "coresight-etm4x-cfg.h" > #include "coresight-self-hosted-trace.h" > #include "coresight-syscfg.h" > +#include "coresight-trace-id.h" > > static int boot_enable; > module_param(boot_enable, int, 0444); > @@ -234,6 +235,30 @@ static int etm4_trace_id(struct coresight_device *csdev) > return drvdata->trcid; > } > > +int etm4_read_alloc_trace_id(struct etmv4_drvdata *drvdata) > +{ > + int trace_id; > + > + /* > + * This will allocate a trace ID to the cpu, > + * or return the one currently allocated. > + * The trace id function has its own lock > + */ > + trace_id = coresight_trace_id_get_cpu_id(drvdata->cpu); > + if (IS_VALID_ID(trace_id)) > + drvdata->trcid = (u8)trace_id; > + else > + dev_err(&drvdata->csdev->dev, > + "Failed to allocate trace ID for %s on CPU%d\n", > + dev_name(&drvdata->csdev->dev), drvdata->cpu); > + return trace_id; > +} > + > +void etm4_release_trace_id(struct etmv4_drvdata *drvdata) > +{ > + coresight_trace_id_put_cpu_id(drvdata->cpu); > +} > + > struct etm4_enable_arg { > struct etmv4_drvdata *drvdata; > int rc; > @@ -717,7 +742,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev, > static int etm4_enable_perf(struct coresight_device *csdev, > struct perf_event *event) > { > - int ret = 0; > + int ret = 0, trace_id; > struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); > > if (WARN_ON_ONCE(drvdata->cpu != smp_processor_id())) { > @@ -729,6 +754,24 @@ static int etm4_enable_perf(struct coresight_device *csdev, > ret = etm4_parse_event_config(csdev, event); > if (ret) > goto out; > + > + /* > + * perf allocates cpu ids as part of _setup_aux() - device needs to use > + * the allocated ID. This reads the current version without allocation. > + * > + * This does not use the trace id lock to prevent lock_dep issues > + * with perf locks - we know the ID cannot change until perf shuts down > + * the session > + */ > + trace_id = coresight_trace_id_read_cpu_id(drvdata->cpu); > + if (!IS_VALID_ID(trace_id)) { > + dev_err(&drvdata->csdev->dev, "Failed to set trace ID for %s on CPU%d\n", > + dev_name(&drvdata->csdev->dev), drvdata->cpu); > + ret = -EINVAL; > + goto out; > + } > + drvdata->trcid = (u8)trace_id; > + > /* And enable it */ > ret = etm4_enable_hw(drvdata); > > @@ -753,6 +796,11 @@ static int etm4_enable_sysfs(struct coresight_device *csdev) > > spin_lock(&drvdata->spinlock); > > + /* sysfs needs to read and allocate a trace ID */ > + ret = etm4_read_alloc_trace_id(drvdata); > + if (ret < 0) > + goto unlock_sysfs_enable; > + > /* > * Executing etm4_enable_hw on the cpu whose ETM is being enabled > * ensures that register writes occur when cpu is powered. > @@ -764,6 +812,11 @@ static int etm4_enable_sysfs(struct coresight_device *csdev) > ret = arg.rc; > if (!ret) > drvdata->sticky_enable = true; > + > + if (ret) > + etm4_release_trace_id(drvdata); > + > +unlock_sysfs_enable: > spin_unlock(&drvdata->spinlock); > > if (!ret) > @@ -895,6 +948,8 @@ static int etm4_disable_perf(struct coresight_device *csdev, > /* TRCVICTLR::SSSTATUS, bit[9] */ > filters->ssstatus = (control & BIT(9)); > > + /* perf will release trace ids when _free_aux() is called at the end of the session */ minor nit: Please split this to multi-line. With that: Reviewed-by: Suzuki K Poulose