Re: [PATCH v4 04/10] coresight: etm-perf: update to handle configuration selection
From: Mathieu Poirier
Date: Wed Feb 24 2021 - 13:34:06 EST
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@xxxxxxxxxx>
> ---
> .../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
>
>
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