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    SubjectRe: [PATCH v4 04/10] coresight: etm-perf: update to handle configuration selection
    On Thu, Jan 28, 2021 at 05:09:30PM +0000, Mike Leach wrote:
    > Loaded coresight configurations are registered in the cs_etm\cs_config sub
    > 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@linaro.org>
    > ---
    > .../hwtracing/coresight/coresight-config.h | 5 +-
    > .../hwtracing/coresight/coresight-etm-perf.c | 164 +++++++++++++++---
    > .../hwtracing/coresight/coresight-etm-perf.h | 8 +
    > .../hwtracing/coresight/coresight-syscfg.c | 13 +-
    > 4 files changed, 166 insertions(+), 24 deletions(-)
    >
    > diff --git a/drivers/hwtracing/coresight/coresight-config.h b/drivers/hwtracing/coresight/coresight-config.h
    > index 9d66e0071f38..98380b496046 100644
    > --- a/drivers/hwtracing/coresight/coresight-config.h
    > +++ b/drivers/hwtracing/coresight/coresight-config.h
    > @@ -154,7 +154,8 @@ struct cscfg_config_feat_ref {
    > * @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.
    > - *
    > + * @id_ea: Extended attribute for perf configid value
    > + * @event_ea: Extended attribute for perf event value
    > */
    > struct cscfg_config_desc {
    > const char *name;
    > @@ -165,6 +166,8 @@ struct cscfg_config_desc {
    > int nr_presets;
    > int nr_total_params;
    > const u64 *presets; /* nr_presets * nr_total_params */
    > + struct dev_ext_attribute *id_ea;
    > + 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 a608081bd446..e270bb1e0f7d 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;
    > @@ -32,8 +34,13 @@ PMU_FORMAT_ATTR(cycacc, "config:" __stringify(ETM_OPT_CYCACC));
    > PMU_FORMAT_ATTR(contextid, "config:" __stringify(ETM_OPT_CTXTID));
    > 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");
    > +
    >
    > static struct attribute *etm_config_formats_attr[] = {
    > &format_attr_cycacc.attr,
    > @@ -41,6 +48,8 @@ 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,
    > };
    >
    > @@ -58,9 +67,29 @@ static const struct attribute_group etm_pmu_sinks_group = {
    > .attrs = etm_config_sinks_attr,
    > };
    >
    > +static struct attribute *etm_config_cscfg_attr[] = {
    > + NULL,
    > +};
    > +
    > +static const struct attribute_group etm_pmu_cscfg_group = {
    > + .name = "configurations",
    > + .attrs = etm_config_cscfg_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_cscfg_group,
    > + &etm_pmu_events_group,
    > NULL,
    > };
    >
    > @@ -219,7 +248,7 @@ 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);
    > }
    > @@ -537,21 +566,17 @@ static ssize_t etm_perf_sink_name_show(struct device *dev,

    I would rename this to etm_perf_name_show() so that it doesn't look bizarre when
    finding it in etm_perf_add_symlink_group().

    > return scnprintf(buf, PAGE_SIZE, "0x%lx\n", (unsigned long)(ea->var));
    > }
    >
    > -int etm_perf_add_symlink_sink(struct coresight_device *csdev)
    > +int etm_perf_add_symlink_group(struct device *dev,
    > + struct dev_ext_attribute **ext_attr,
    > + 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;
    > + *ext_attr = NULL;
    >
    > if (!etm_perf_up)
    > return -EPROBE_DEFER;
    > @@ -560,7 +585,6 @@ int etm_perf_add_symlink_sink(struct coresight_device *csdev)
    > if (!ea)
    > return -ENOMEM;
    >
    > - name = dev_name(dev);
    > /* See function coresight_get_sink_by_id() to know where this is used */

    I would also update this comment. If @name is a sink then the hash will be
    used in coresight_get_sink_by_id(), and if it is a configuration it will be used
    in etm_perf_add_cscfg_event() and cscfg_activate_config().

    > hash = hashlen_hash(hashlen_string(NULL, name));
    >
    > @@ -574,31 +598,127 @@ int etm_perf_add_symlink_sink(struct coresight_device *csdev)
    > 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;
    > -
    > + *ext_attr = ea;
    > return ret;
    > }
    >
    > -void etm_perf_del_symlink_sink(struct coresight_device *csdev)
    > +int etm_perf_add_symlink_sink(struct coresight_device *csdev)
    > +{
    > + const char *name;
    > + struct device *dev = &csdev->dev;
    > +
    > + 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);
    > + return etm_perf_add_symlink_group(dev, &csdev->ea, name, "sinks");
    > +}
    > +
    > +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;
    > }
    >
    > +/* string to contain the attribute value */
    > +#define CSCFG_EVENT_STR_SIZE 32
    > +
    > +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, "%s\n", (const char *)(ea->var));
    > +}
    > +
    > +static int etm_perf_add_cscfg_event(struct device *dev, struct cscfg_config_desc *cs_cfg)
    > +{
    > + struct dev_ext_attribute *ea;
    > + unsigned long hash;
    > + int ret;
    > + struct device *pmu_dev = etm_pmu.dev;
    > +
    > + ea = devm_kzalloc(dev, sizeof(*ea), GFP_KERNEL);
    > + if (!ea)
    > + return -ENOMEM;
    > +
    > + hash = (unsigned long)cs_cfg->id_ea->var;
    > +
    > + sysfs_attr_init(&ea->attr.attr);
    > + ea->attr.attr.name = devm_kstrdup(dev, cs_cfg->name, GFP_KERNEL);
    > + if (!ea->attr.attr.name)
    > + return -ENOMEM;
    > +
    > + /*
    > + * attribute value is "configid=<hash>".
    > + * this will be what perf evaluates when the config name is used
    > + * on the command line.
    > + */
    > + ea->var = devm_kzalloc(dev, CSCFG_EVENT_STR_SIZE, GFP_KERNEL);
    > + if (!ea->var)
    > + return -ENOMEM;
    > +
    > + scnprintf(ea->var, CSCFG_EVENT_STR_SIZE, "configid=0x%lx", hash);
    > + ea->attr.attr.mode = 0444;
    > + ea->attr.show = etm_perf_cscfg_event_show;
    > +
    > + ret = sysfs_add_file_to_group(&pmu_dev->kobj,
    > + &ea->attr.attr, "events");
    > + if (!ret)
    > + cs_cfg->event_ea = ea;
    > + return ret;
    > +}
    > +
    > +int etm_perf_add_symlink_cscfg(struct device *dev, struct cscfg_config_desc *cs_cfg)
    > +{
    > + int err;
    > +
    > + if (cs_cfg->id_ea != NULL)
    > + return 0;
    > +
    > + err = etm_perf_add_symlink_group(dev, &cs_cfg->id_ea,
    > + cs_cfg->name, "configurations");

    Do we need configurations to be advertised under
    /sys/bus/event_source/devices/cs_etm given that they are already found in
    /sys/kernel/config/coresight-syscfg? And the events already carry the hash if
    someone is really keen using the "configid=" syntax.

    In my opinion we can get by with what is in configfs and do away with the
    "configurations" directory here.

    > +
    > + if (!err)
    > + err = etm_perf_add_cscfg_event(dev, cs_cfg);
    > +

    That we definitely need.

    Thanks,
    Mathieu

    > + return err;
    > +}
    > +
    > +void etm_perf_del_symlink_cscfg(struct cscfg_config_desc *cs_cfg)
    > +{
    > + if (!cs_cfg->id_ea)
    > + return;
    > +
    > + etm_perf_del_symlink_group(cs_cfg->id_ea, "configurations");
    > + etm_perf_del_symlink_group(cs_cfg->event_ea, "events");
    > + cs_cfg->id_ea = NULL;
    > + cs_cfg->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..3646a3837a0b 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 *cscfg_desc);
    > +void etm_perf_del_symlink_cscfg(struct cscfg_config_desc *cscfg_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 *cscfg_desc)
    > +{ return -EINVAL; }
    > +void etm_perf_del_symlink_cscfg(struct cscfg_config_desc *cscfg_desc) {}
    >
    > #endif /* CONFIG_CORESIGHT */
    >
    > diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
    > index 4b8e4e35e3e7..a070f135eca3 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"
    >
    > /*
    > @@ -100,6 +101,7 @@ static int cscfg_add_csdev_cfg(struct coresight_device *csdev,
    > dev_cfg->feats[dev_cfg->nr_feat++] = feat;
    > }
    > }
    > +
    > /* if matched features, add config to device.*/
    > if (dev_cfg) {
    > mutex_lock(&cscfg_csdev_mutex);
    > @@ -290,8 +292,12 @@ static int cscfg_load_config(struct cscfg_config_desc *cfg_desc)
    > if (err)
    > return err;
    >
    > - list_add(&cfg_desc->item, &cscfg_mgr->data.config_desc_list);
    > + /* add config to perf fs to allow selection */
    > + err = etm_perf_add_symlink_cscfg(to_device_cscfg(), cfg_desc);
    > + if (err)
    > + return err;
    >
    > + list_add(&cfg_desc->item, &cscfg_mgr->data.config_desc_list);
    > return 0;
    > }
    >
    > @@ -517,7 +523,12 @@ 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->data.config_desc_list, item) {
    > + etm_perf_del_symlink_cscfg(cfg_desc);
    > + }
    > device_unregister(to_device_cscfg());
    > mutex_unlock(&cscfg_mutex);
    > }
    > --
    > 2.17.1
    >
    >
    > _______________________________________________
    > linux-arm-kernel mailing list
    > linux-arm-kernel@lists.infradead.org
    > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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