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[68.147.8.254]) by smtp.gmail.com with ESMTPSA id e3sm1783781pgr.80.2018.04.02.14.57.35 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 02 Apr 2018 14:57:36 -0700 (PDT) Date: Mon, 2 Apr 2018 15:57:33 -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 6/6] coresight: etm4x: Support panic kdump Message-ID: <20180402215733.GF15452@xps15> References: <1522379724-30648-1-git-send-email-leo.yan@linaro.org> <1522379724-30648-7-git-send-email-leo.yan@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1522379724-30648-7-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 11:15:24AM +0800, Leo Yan wrote: > ETMv4 hardware information and configuration needs to be saved as > metadata; the metadata format should be compatible with 'perf' tool and > finally is used by tracing data decoder. ETMv4 works as tracer per CPU, > we cannot wait for gathering ETM info after CPU panic has happened in > case there have CPU is locked up and can't response inter-processor > interrupt for execution dump operations; so it's more reliable to gather > tracer metadata when all of the CPUs are alive. > > This patch saves ETMv4 metadata but with the different method for > different registers. Since values in TRCIDR{0, 1, 2, 8} and > TRCAUTHSTATUS are read-only and won't change afterward, thus those > registers values are filled into metadata structure when tracers are > instantiated. The configuration and control registers TRCCONFIGR and > TRCTRACEIDR are dynamically configured, their values are recorded during > tracer enabling phase. > > To avoid unnecessary overload introduced by set/clear operations for > updating kdump node, we only set ETMv4 metadata info for the > corresponding kdump node at initialization and won't be cleared anymore. > > Suggested-by: Mathieu Poirier > Signed-off-by: Leo Yan > --- > drivers/hwtracing/coresight/coresight-etm4x.c | 27 +++++++++++++++++++++++++++ > drivers/hwtracing/coresight/coresight-etm4x.h | 15 +++++++++++++++ > 2 files changed, 42 insertions(+) > > diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c > index cf364a5..88b1e19 100644 > --- a/drivers/hwtracing/coresight/coresight-etm4x.c > +++ b/drivers/hwtracing/coresight/coresight-etm4x.c > @@ -288,6 +288,8 @@ static int etm4_enable(struct coresight_device *csdev, > int ret; > u32 val; > struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); > + struct etmv4_config *config = &drvdata->config; > + struct etmv4_metadata *metadata = &drvdata->metadata; > > val = local_cmpxchg(&drvdata->mode, CS_MODE_DISABLED, mode); > > @@ -306,6 +308,10 @@ static int etm4_enable(struct coresight_device *csdev, > ret = -EINVAL; > } > > + /* Update tracer meta data after tracer configuration */ > + metadata->trcconfigr = config->cfg; > + metadata->trctraceidr = drvdata->trcid; > + > /* The tracer didn't start */ > if (ret) > local_set(&drvdata->mode, CS_MODE_DISABLED); > @@ -438,6 +444,7 @@ static void etm4_init_arch_data(void *info) > u32 etmidr4; > u32 etmidr5; > struct etmv4_drvdata *drvdata = info; > + struct etmv4_metadata *metadata = &drvdata->metadata; > > /* Make sure all registers are accessible */ > etm4_os_unlock(drvdata); > @@ -590,6 +597,16 @@ static void etm4_init_arch_data(void *info) > drvdata->nrseqstate = BMVAL(etmidr5, 25, 27); > /* NUMCNTR, bits[30:28] number of counters available for tracing */ > drvdata->nr_cntr = BMVAL(etmidr5, 28, 30); > + > + /* Update metadata */ > + metadata->magic = ETM4_METADATA_MAGIC; > + metadata->cpu = drvdata->cpu; > + metadata->trcidr0 = readl_relaxed(drvdata->base + TRCIDR0); > + metadata->trcidr1 = readl_relaxed(drvdata->base + TRCIDR1); > + metadata->trcidr2 = readl_relaxed(drvdata->base + TRCIDR2); > + metadata->trcidr8 = readl_relaxed(drvdata->base + TRCIDR8); > + metadata->trcauthstatus = readl_relaxed(drvdata->base + TRCAUTHSTATUS); > + > CS_LOCK(drvdata->base); > } > > @@ -957,6 +974,7 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id) > struct device *dev = &adev->dev; > struct coresight_platform_data *pdata = NULL; > struct etmv4_drvdata *drvdata; > + struct etmv4_metadata *metadata; > struct resource *res = &adev->res; > struct coresight_desc desc = { 0 }; > struct device_node *np = adev->dev.of_node; > @@ -1027,6 +1045,15 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id) > goto err_arch_supported; > } > > + /* Set source device handler and metadata into kdump node */ > + metadata = &drvdata->metadata; > + ret = coresight_kdump_source(drvdata->cpu, drvdata->csdev, > + (char *)metadata, sizeof(*metadata)); > + if (ret) { > + coresight_unregister(drvdata->csdev); > + goto err_arch_supported; > + } > + > ret = etm_perf_symlink(drvdata->csdev, true); > if (ret) { > coresight_unregister(drvdata->csdev); > diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h > index b3b5ea7..08dc8b7 100644 > --- a/drivers/hwtracing/coresight/coresight-etm4x.h > +++ b/drivers/hwtracing/coresight/coresight-etm4x.h > @@ -198,6 +198,20 @@ > #define ETM_EXLEVEL_NS_HYP BIT(14) > #define ETM_EXLEVEL_NS_NA BIT(15) > > +#define ETM4_METADATA_MAGIC 0x4040404040404040ULL Please dd a comment that this needs to be kept in sync with __perf_cs_etmv4_magic in tools/perf/util/cs-etm.h. > + > +struct etmv4_metadata { > + u64 magic; > + u64 cpu; > + u64 trcconfigr; > + u64 trctraceidr; > + u64 trcidr0; > + u64 trcidr1; > + u64 trcidr2; > + u64 trcidr8; > + u64 trcauthstatus; > +}; > + > /** > * struct etmv4_config - configuration information related to an ETMv4 > * @mode: Controls various modes supported by this ETM. > @@ -393,6 +407,7 @@ struct etmv4_drvdata { > bool atbtrig; > bool lpoverride; > struct etmv4_config config; > + struct etmv4_metadata metadata; Structure documentation please. > }; > > /* Address comparator access types */ > -- > 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