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[68.147.8.254]) by smtp.gmail.com with ESMTPSA id w26sm2773204pfi.17.2018.04.02.14.34.39 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 02 Apr 2018 14:34:40 -0700 (PDT) Date: Mon, 2 Apr 2018 15:34:37 -0600 From: Mathieu Poirier To: Leo Yan Cc: Jonathan Corbet , Greg Kroah-Hartman , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, coresight@lists.linaro.org, Kim Phillips , Mike Leach Subject: Re: [PATCH v4 5/6] coresight: Set and clear sink device handler for kdump node Message-ID: <20180402213437.GE15452@xps15> References: <1522379724-30648-1-git-send-email-leo.yan@linaro.org> <1522379724-30648-6-git-send-email-leo.yan@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1522379724-30648-6-git-send-email-leo.yan@linaro.org> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Fri, Mar 30, 2018 at 11:15:23AM +0800, Leo Yan wrote: > If Coresight path is enabled for specific CPU, the sink device handler > need to be set to kdump node; on the other hand we also need to clear > sink device handler when path is disabled. > > This patch sets sink devices handler for kdump node for two separate > Coresight enabling modes: CS_MODE_SYSFS and CS_MODE_PERF; and clear the > handler when Coresight is disabled. > > Signed-off-by: Leo Yan > --- > drivers/hwtracing/coresight/coresight-etm-perf.c | 5 +++++ > drivers/hwtracing/coresight/coresight.c | 16 ++++++++++++++-- > 2 files changed, 19 insertions(+), 2 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c > index 8a0ad77..f8b159c 100644 > --- a/drivers/hwtracing/coresight/coresight-etm-perf.c > +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c > @@ -139,6 +139,8 @@ static void free_event_data(struct work_struct *work) > for_each_cpu(cpu, mask) { > if (!(IS_ERR_OR_NULL(event_data->path[cpu]))) > coresight_release_path(event_data->path[cpu]); > + > + coresight_kdump_sink(cpu, NULL); > } > > kfree(event_data->path); > @@ -238,6 +240,9 @@ static void *etm_setup_aux(int event_cpu, void **pages, > event_data->path[cpu] = coresight_build_path(csdev, sink); > if (IS_ERR(event_data->path[cpu])) > goto err; > + > + if (coresight_kdump_sink(cpu, sink)) > + goto err; I remember telling you to use free_event_data() and etm_setup_aux(). _Maybe_ it made sense in the previous patchset but in this one it won't work. We need to reflect the current trace context, as such use etm_event_start() and etm_event_stop(). In etm_event_start() call coresight_kdump_sink(cpu, sink) just before source_ops(csdev)->enable(). Similarly call coresight_kdump_sink(cpu, NULL) right after source_ops(csdev)->disable() in etm_event_stop(). Find me on IRC if you want more information on this. > } > > if (!sink_ops(sink)->alloc_buffer) > diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c > index 389c4ba..483a1f7 100644 > --- a/drivers/hwtracing/coresight/coresight.c > +++ b/drivers/hwtracing/coresight/coresight.c > @@ -272,6 +272,7 @@ static int coresight_enable_source(struct coresight_device *csdev, u32 mode) > static bool coresight_disable_source(struct coresight_device *csdev) > { > if (atomic_dec_return(csdev->refcnt) == 0) { > + This newline shouldn't be part of this set. > if (source_ops(csdev)->disable) > source_ops(csdev)->disable(csdev, NULL); > csdev->enable = false; > @@ -612,6 +613,13 @@ int coresight_enable(struct coresight_device *csdev) > if (ret) > goto err_source; > > + cpu = source_ops(csdev)->cpu_id(csdev); > + > + /* Set sink device handler into kdump node */ > + ret = coresight_kdump_sink(cpu, sink); > + if (ret) > + goto err_kdump; > + Call coresight_kdump_sink() just before coresight_enable_source(). That way if there is a dump just after coresight_enable_source() is called we get the chance of getting some traces in the dump file. > switch (subtype) { > case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC: > /* > @@ -621,7 +629,6 @@ int coresight_enable(struct coresight_device *csdev) > * be a single session per tracer (when working from sysFS) > * a per-cpu variable will do just fine. > */ > - cpu = source_ops(csdev)->cpu_id(csdev); > per_cpu(tracer_path, cpu) = path; > break; > case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE: > @@ -636,6 +643,9 @@ int coresight_enable(struct coresight_device *csdev) > mutex_unlock(&coresight_mutex); > return ret; > > +err_kdump: > + coresight_disable_source(csdev); > + > err_source: > coresight_disable_path(path); > > @@ -659,9 +669,10 @@ void coresight_disable(struct coresight_device *csdev) > if (!csdev->enable || !coresight_disable_source(csdev)) > goto out; > > + cpu = source_ops(csdev)->cpu_id(csdev); > + > switch (csdev->subtype.source_subtype) { > case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC: > - cpu = source_ops(csdev)->cpu_id(csdev); > path = per_cpu(tracer_path, cpu); > per_cpu(tracer_path, cpu) = NULL; > break; > @@ -674,6 +685,7 @@ void coresight_disable(struct coresight_device *csdev) > break; > } > > + coresight_kdump_sink(cpu, NULL); > coresight_disable_path(path); > coresight_release_path(path); > > -- > 2.7.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html