Re: [PATCH v5 04/10] coresight: etm-perf: update to handle configuration selection

From: Mathieu Poirier
Date: Wed Mar 31 2021 - 16:49:58 EST

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On Tue, Mar 16, 2021 at 06:03:54PM +0000, Mike Leach wrote:
> Loaded coresight configurations are registered in the cs_etm\cs_config sub

This changelog is obsolete - cs_config is no longer under cs_etm.

> directory. This extends the etm-perf code to handle these registrations,
> and the cs_syscfg driver to perform the registration on load.
>
> Signed-off-by: Mike Leach <mike.leach@xxxxxxxxxx>
> ---
> .../hwtracing/coresight/coresight-config.h | 2 +
> .../hwtracing/coresight/coresight-etm-perf.c | 139 ++++++++++++++----
> .../hwtracing/coresight/coresight-etm-perf.h | 8 +
> .../hwtracing/coresight/coresight-syscfg.c | 12 ++
> 4 files changed, 130 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-config.h b/drivers/hwtracing/coresight/coresight-config.h
> index f70561c1504b..38fd1c71eb05 100644
> --- a/drivers/hwtracing/coresight/coresight-config.h
> +++ b/drivers/hwtracing/coresight/coresight-config.h
> @@ -126,6 +126,7 @@ struct cscfg_feature_desc {
> * @nr_presets: Number of sets of presets supplied by this configuration.
> * @nr_total_params: Sum of all parameters declared by used features
> * @presets: Array of preset values.
> + * @event_ea: Extended attribute for perf event value
> *
> */
> struct cscfg_config_desc {
> @@ -137,6 +138,7 @@ struct cscfg_config_desc {
> int nr_presets;
> int nr_total_params;
> const u64 *presets; /* nr_presets * nr_total_params */
> + struct dev_ext_attribute *event_ea;
> };
>
> /**
> diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
> index 0e392513b2d6..66bda452a2f4 100644
> --- a/drivers/hwtracing/coresight/coresight-etm-perf.c
> +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
> @@ -18,8 +18,10 @@
> #include <linux/types.h>
> #include <linux/workqueue.h>
>
> +#include "coresight-config.h"
> #include "coresight-etm-perf.h"
> #include "coresight-priv.h"
> +#include "coresight-syscfg.h"
>
> static struct pmu etm_pmu;
> static bool etm_perf_up;
> @@ -38,8 +40,13 @@ PMU_FORMAT_ATTR(contextid1, "config:" __stringify(ETM_OPT_CTXTID));
> PMU_FORMAT_ATTR(contextid2, "config:" __stringify(ETM_OPT_CTXTID2));
> PMU_FORMAT_ATTR(timestamp, "config:" __stringify(ETM_OPT_TS));
> PMU_FORMAT_ATTR(retstack, "config:" __stringify(ETM_OPT_RETSTK));
> +/* preset - if sink ID is used as a configuration selector */
> +PMU_FORMAT_ATTR(preset, "config:0-3");
> /* Sink ID - same for all ETMs */
> PMU_FORMAT_ATTR(sinkid, "config2:0-31");
> +/* config ID - set if a system configuration is selected */
> +PMU_FORMAT_ATTR(configid, "config2:32-63");
> +
>
> /*
> * contextid always traces the "PID". The PID is in CONTEXTIDR_EL1
> @@ -69,6 +76,8 @@ static struct attribute *etm_config_formats_attr[] = {
> &format_attr_timestamp.attr,
> &format_attr_retstack.attr,
> &format_attr_sinkid.attr,
> + &format_attr_preset.attr,
> + &format_attr_configid.attr,
> NULL,
> };
>
> @@ -86,9 +95,19 @@ static const struct attribute_group etm_pmu_sinks_group = {
> .attrs = etm_config_sinks_attr,
> };
>
> +static struct attribute *etm_config_events_attr[] = {
> + NULL,
> +};
> +
> +static const struct attribute_group etm_pmu_events_group = {
> + .name = "events",
> + .attrs = etm_config_events_attr,
> +};
> +
> static const struct attribute_group *etm_pmu_attr_groups[] = {
> &etm_pmu_format_group,
> &etm_pmu_sinks_group,
> + &etm_pmu_events_group,
> NULL,
> };
>
> @@ -247,7 +266,7 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
> INIT_WORK(&event_data->work, free_event_data);
>
> /* First get the selected sink from user space. */
> - if (event->attr.config2) {
> + if (event->attr.config2 & GENMASK_ULL(31, 0)) {
> id = (u32)event->attr.config2;
> sink = coresight_get_sink_by_id(id);
> }
> @@ -555,9 +574,9 @@ int etm_perf_symlink(struct coresight_device *csdev, bool link)
> }
> EXPORT_SYMBOL_GPL(etm_perf_symlink);
>
> -static ssize_t etm_perf_sink_name_show(struct device *dev,
> - struct device_attribute *dattr,
> - char *buf)

Because we now have etm_perf_cscfg_event_show(), this could have remained
unchanged.

> +static ssize_t etm_perf_name_show(struct device *dev,
> + struct device_attribute *dattr,
> + char *buf)
> {
> struct dev_ext_attribute *ea;
>
> @@ -565,68 +584,126 @@ static ssize_t etm_perf_sink_name_show(struct device *dev,
> return scnprintf(buf, PAGE_SIZE, "0x%lx\n", (unsigned long)(ea->var));
> }
>
> -int etm_perf_add_symlink_sink(struct coresight_device *csdev)
> +static struct dev_ext_attribute *
> +etm_perf_add_symlink_group(struct device *dev, const char *name, const char *group_name)
> {
> - int ret;
> + struct dev_ext_attribute *ea;
> unsigned long hash;
> - const char *name;
> + int ret;
> struct device *pmu_dev = etm_pmu.dev;
> - struct device *dev = &csdev->dev;
> - struct dev_ext_attribute *ea;
> -
> - if (csdev->type != CORESIGHT_DEV_TYPE_SINK &&
> - csdev->type != CORESIGHT_DEV_TYPE_LINKSINK)
> - return -EINVAL;
> -
> - if (csdev->ea != NULL)
> - return -EINVAL;
>
> if (!etm_perf_up)
> - return -EPROBE_DEFER;
> + return ERR_PTR(-EPROBE_DEFER);
>
> ea = devm_kzalloc(dev, sizeof(*ea), GFP_KERNEL);
> if (!ea)
> - return -ENOMEM;
> + return ERR_PTR(-ENOMEM);
>
> - name = dev_name(dev);
> - /* See function coresight_get_sink_by_id() to know where this is used */
> + /*
> + * If this function is called adding a sink then the hash is used for
> + * sink selection - see function coresight_get_sink_by_id().
> + * If adding a configuration then the hash is used for selection in
> + * cscfg_activate_config()
> + */
> hash = hashlen_hash(hashlen_string(NULL, name));
>
> sysfs_attr_init(&ea->attr.attr);
> ea->attr.attr.name = devm_kstrdup(dev, name, GFP_KERNEL);
> if (!ea->attr.attr.name)
> - return -ENOMEM;
> + return ERR_PTR(-ENOMEM);
>
> ea->attr.attr.mode = 0444;
> - ea->attr.show = etm_perf_sink_name_show;
> + ea->attr.show = etm_perf_name_show;

I would have removed the assignment entirely from this function and moved it to
etm_perf_add_symlink_cscfg() (like you already did) and
etm_perf_add_symlink_link().

> ea->var = (unsigned long *)hash;
>
> ret = sysfs_add_file_to_group(&pmu_dev->kobj,
> - &ea->attr.attr, "sinks");
> + &ea->attr.attr, group_name);
>
> - if (!ret)
> - csdev->ea = ea;
> + return ret ? ERR_PTR(ret) : ea;
> +}
>
> - return ret;
> +int etm_perf_add_symlink_sink(struct coresight_device *csdev)
> +{
> + const char *name;
> + struct device *dev = &csdev->dev;
> + int err = 0;
> +
> + if (csdev->type != CORESIGHT_DEV_TYPE_SINK &&
> + csdev->type != CORESIGHT_DEV_TYPE_LINKSINK)
> + return -EINVAL;
> +
> + if (csdev->ea != NULL)
> + return -EINVAL;
> +
> + name = dev_name(dev);
> + csdev->ea = etm_perf_add_symlink_group(dev, name, "sinks");
> + if (IS_ERR(csdev->ea)) {
> + err = PTR_ERR(csdev->ea);
> + csdev->ea = NULL;
> + }
> + return err;
> }
>
> -void etm_perf_del_symlink_sink(struct coresight_device *csdev)
> +void etm_perf_del_symlink_group(struct dev_ext_attribute *ea, const char *group_name)
> {
> struct device *pmu_dev = etm_pmu.dev;
> - struct dev_ext_attribute *ea = csdev->ea;
>
> + sysfs_remove_file_from_group(&pmu_dev->kobj,
> + &ea->attr.attr, group_name);
> +}
> +
> +void etm_perf_del_symlink_sink(struct coresight_device *csdev)
> +{
> if (csdev->type != CORESIGHT_DEV_TYPE_SINK &&
> csdev->type != CORESIGHT_DEV_TYPE_LINKSINK)
> return;
>
> - if (!ea)
> + if (!csdev->ea)
> return;
>
> - sysfs_remove_file_from_group(&pmu_dev->kobj,
> - &ea->attr.attr, "sinks");
> + etm_perf_del_symlink_group(csdev->ea, "sinks");
> csdev->ea = NULL;
> }
>
> +static ssize_t etm_perf_cscfg_event_show(struct device *dev,
> + struct device_attribute *dattr,
> + char *buf)
> +{
> + struct dev_ext_attribute *ea;
> +
> + ea = container_of(dattr, struct dev_ext_attribute, attr);
> + return scnprintf(buf, PAGE_SIZE, "configid=0x%lx\n", (unsigned long)(ea->var));
> +}
> +
> +int etm_perf_add_symlink_cscfg(struct device *dev, struct cscfg_config_desc *config_desc)
> +{
> + int err = 0;
> +
> + if (config_desc->event_ea != NULL)
> + return 0;
> +
> + config_desc->event_ea = etm_perf_add_symlink_group(dev, config_desc->name, "events");
> +
> + /* override the show function to the custom cscfg event */
> + if (!IS_ERR(config_desc->event_ea))
> + config_desc->event_ea->attr.show = etm_perf_cscfg_event_show;
> + else {
> + err = PTR_ERR(config_desc->event_ea);
> + config_desc->event_ea = NULL;
> + }
> +
> + return err;
> +}
> +
> +void etm_perf_del_symlink_cscfg(struct cscfg_config_desc *config_desc)
> +{
> + if (!config_desc->event_ea)
> + return;
> +
> + etm_perf_del_symlink_group(config_desc->event_ea, "events");
> + config_desc->event_ea = NULL;
> +}
> +
> int __init etm_perf_init(void)
> {
> int ret;
> diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.h b/drivers/hwtracing/coresight/coresight-etm-perf.h
> index 29d90dfeba31..ba617fe2217e 100644
> --- a/drivers/hwtracing/coresight/coresight-etm-perf.h
> +++ b/drivers/hwtracing/coresight/coresight-etm-perf.h
> @@ -11,6 +11,7 @@
> #include "coresight-priv.h"
>
> struct coresight_device;
> +struct cscfg_config_desc;
>
> /*
> * In both ETMv3 and v4 the maximum number of address comparator implentable
> @@ -69,6 +70,9 @@ static inline void *etm_perf_sink_config(struct perf_output_handle *handle)
> return data->snk_config;
> return NULL;
> }
> +int etm_perf_add_symlink_cscfg(struct device *dev,
> + struct cscfg_config_desc *config_desc);
> +void etm_perf_del_symlink_cscfg(struct cscfg_config_desc *config_desc);
> #else
> static inline int etm_perf_symlink(struct coresight_device *csdev, bool link)
> { return -EINVAL; }
> @@ -79,6 +83,10 @@ static inline void *etm_perf_sink_config(struct perf_output_handle *handle)
> {
> return NULL;
> }
> +int etm_perf_add_symlink_cscfg(struct device *dev,
> + struct cscfg_config_desc *config_desc)
> +{ return -EINVAL; }
> +void etm_perf_del_symlink_cscfg(struct cscfg_config_desc *config_desc) {}
>
> #endif /* CONFIG_CORESIGHT */
>
> diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
> index 11d1422f0ed3..03014a2142c1 100644
> --- a/drivers/hwtracing/coresight/coresight-syscfg.c
> +++ b/drivers/hwtracing/coresight/coresight-syscfg.c
> @@ -7,6 +7,7 @@
> #include <linux/platform_device.h>
>
> #include "coresight-config.h"
> +#include "coresight-etm-perf.h"
> #include "coresight-syscfg.h"
>
> /*
> @@ -86,6 +87,7 @@ static int cscfg_add_csdev_cfg(struct coresight_device *csdev,
> config_csdev->feats_csdev[config_csdev->nr_feat++] = feat_csdev;
> }
> }
> +

Spurious newline.

If you end up respinning:

Reviewed-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>

Otherwise I have fixed it on my side.

Thanks,
Mathieu

> /* if matched features, add config to device.*/
> if (config_csdev) {
> mutex_lock(&cscfg_csdev_mutex);
> @@ -276,6 +278,11 @@ static int cscfg_load_config(struct cscfg_config_desc *config_desc)
> if (err)
> return err;
>
> + /* add config to perf fs to allow selection */
> + err = etm_perf_add_symlink_cscfg(cscfg_device(), config_desc);
> + if (err)
> + return err;
> +
> list_add(&config_desc->item, &cscfg_mgr->config_desc_list);
> return 0;
> }
> @@ -490,7 +497,12 @@ int cscfg_create_device(void)
>
> void cscfg_clear_device(void)
> {
> + struct cscfg_config_desc *cfg_desc;
> +
> mutex_lock(&cscfg_mutex);
> + list_for_each_entry(cfg_desc, &cscfg_mgr->config_desc_list, item) {
> + etm_perf_del_symlink_cscfg(cfg_desc);
> + }
> device_unregister(cscfg_device());
> mutex_unlock(&cscfg_mutex);
> }
> --
> 2.17.1
>

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