Re: [RFC PATCH 4/8] coresight: configfs: Allow configfs to activate configuration.

Hi Mathieu,

On Tue, 18 May 2021 at 20:36, Mathieu Poirier mathieu.poirier@linaro.org wrote:

Please remove the '.' on every patch header.

Sorry - will do. Correct punctuation seems to be a habit that is hard to break!

On Wed, May 12, 2021 at 10:17:48PM +0100, Mike Leach wrote:

...

Adds configfs attributes to allow a configuration to be enabled for use when sysfs is used to control CoreSight.

perf retains independent enabling of configurations.

Signed-off-by: Mike Leach mike.leach@linaro.org

.../coresight/coresight-etm4x-core.c | 5 + .../coresight/coresight-syscfg-configfs.c | 67 +++++++++ .../coresight/coresight-syscfg-configfs.h | 2 + .../hwtracing/coresight/coresight-syscfg.c | 129 ++++++++++++++---- .../hwtracing/coresight/coresight-syscfg.h | 7 +- 5 files changed, 182 insertions(+), 28 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index b7a4aeaa2bc7..2637096c4621 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -688,6 +688,11 @@ static int etm4_enable_sysfs(struct coresight_device *csdev) struct etm4_enable_arg arg = { }; int ret;

• /* enable any config activated by configfs */
  

• ret = cscfg_csdev_enable_active_config(csdev, 0, 0);
  

• if (ret)
  

•         return ret;
  

• spin_lock(&drvdata->spinlock);
  
  /*
  

diff --git a/drivers/hwtracing/coresight/coresight-syscfg-configfs.c b/drivers/hwtracing/coresight/coresight-syscfg-configfs.c index 345a62f1b728..ae79ae8b1d7e 100644 --- a/drivers/hwtracing/coresight/coresight-syscfg-configfs.c +++ b/drivers/hwtracing/coresight/coresight-syscfg-configfs.c @@ -6,6 +6,7 @@

#include <linux/configfs.h>

+#include "coresight-config.h" #include "coresight-syscfg-configfs.h"

/* create a default ci_type. */ @@ -87,9 +88,75 @@ static ssize_t cscfg_cfg_values_show(struct config_item *item, char *page) } CONFIGFS_ATTR_RO(cscfg_cfg_, values);

+static ssize_t cscfg_cfg_activate_show(struct config_item *item, char *page) +{

• struct cscfg_fs_config *fs_config = container_of(to_config_group(item),
  

•                                                  struct cscfg_fs_config, group);
  

• return scnprintf(page, PAGE_SIZE, "%d\n", fs_config->active);
  

+}

+static ssize_t cscfg_cfg_activate_store(struct config_item *item,

•                                 const char *page, size_t count)
  

+{

• struct cscfg_fs_config *fs_config = container_of(to_config_group(item),
  

•                                                  struct cscfg_fs_config, group);
  

• int err;
  

• bool val;
  

• err = kstrtobool(page, &val);
  

• if (!err)
  

•         err = cscfg_config_sysfs_activation(fs_config->config_desc, val);
  

• if (!err) {
  

•         fs_config->active = val;
  

•         if (val)
  

•                 cscfg_config_sysfs_preset(fs_config->preset);
  

• }
  

• return err ? err : count;
  

+} +CONFIGFS_ATTR(cscfg_cfg_, activate);

+static ssize_t cscfg_cfg_active_preset_show(struct config_item *item, char *page) +{

• struct cscfg_fs_config *fs_config = container_of(to_config_group(item),
  

•                                                  struct cscfg_fs_config, group);
  

• return scnprintf(page, PAGE_SIZE, "%d\n", fs_config->preset);
  

+}

+static ssize_t cscfg_cfg_active_preset_store(struct config_item *item,

•                                      const char *page, size_t count)
  

+{

• struct cscfg_fs_config *fs_config = container_of(to_config_group(item),
  

•                                                  struct cscfg_fs_config, group);
  

• int preset, err;
  

• err = kstrtoint(page, 0, &preset);
  

• if (!err) {
  

•         /*
  

•          * presets start at 1, and go up to max (15),
  

•          * but the config may provide fewer.
  

•          */
  

•         if ((preset < 1) || (preset > fs_config->config_desc->nr_presets))
  

•                 err = -EINVAL;
  

• }
  

• if (!err) {
  

•         /* set new value */
  

•         fs_config->preset = preset;
  

•         /* set on system if active */
  

•         if (fs_config->active)
  

•                 cscfg_config_sysfs_preset(fs_config->preset);
  

• }
  

• return err ? err : count;
  

+} +CONFIGFS_ATTR(cscfg_cfg_, active_preset);

static struct configfs_attribute *cscfg_config_view_attrs[] = { &cscfg_cfg_attr_description, &cscfg_cfg_attr_feature_refs,

• &cscfg_cfg_attr_activate,
  

• &cscfg_cfg_attr_active_preset,
  NULL,
  

};

diff --git a/drivers/hwtracing/coresight/coresight-syscfg-configfs.h b/drivers/hwtracing/coresight/coresight-syscfg-configfs.h index ea1e54d29f7f..373d84d43268 100644 --- a/drivers/hwtracing/coresight/coresight-syscfg-configfs.h +++ b/drivers/hwtracing/coresight/coresight-syscfg-configfs.h @@ -15,6 +15,8 @@ struct cscfg_fs_config { struct cscfg_config_desc *config_desc; struct config_group group;

• bool active;
  

• int preset;
  

};

/* container for feature view */ diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c index 26c1a244c2b1..ab74e33b892b 100644 --- a/drivers/hwtracing/coresight/coresight-syscfg.c +++ b/drivers/hwtracing/coresight/coresight-syscfg.c @@ -743,32 +743,23 @@ void cscfg_csdev_reset_feats(struct coresight_device *csdev) } EXPORT_SYMBOL_GPL(cscfg_csdev_reset_feats);

-/**

• • cscfg_activate_config - Mark a configuration descriptor as active.
• • This will be seen when csdev devices are enabled in the system.
• • Only activated configurations can be enabled on individual devices.
• • Activation protects the configuration from alteration or removal while
• • active.
• • Selection by hash value - generated from the configuration name when it
• • was loaded and added to the cs_etm/configurations file system for selection
• • by perf.

+/*

• • This activate configuration for either perf or sysfs. Perf can have multiple
• • active configs, selected per event, sysfs is limited to one.
  • Increments the configuration descriptor active count and the global active
  • count.
  • @cfg_hash: Hash value of the selected configuration name.
  */

-int cscfg_activate_config(unsigned long cfg_hash) +static int _cscfg_activate_config(unsigned long cfg_hash) { struct cscfg_config_desc *config_desc; int err = -EINVAL;

• mutex_lock(&cscfg_mutex);
  

• list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) {
          if ((unsigned long)config_desc->event_ea->var == cfg_hash) {
  

Spurious newline

...

                  /* must ensure that config cannot be unloaded in use */
                  err = cscfg_owner_get(config_desc->load_owner);
                  if (err)

@@ -790,6 +781,88 @@ int cscfg_activate_config(unsigned long cfg_hash) break; } }

• return err;
  

+}

+static void _cscfg_deactivate_config(unsigned long cfg_hash) +{

• struct cscfg_config_desc *config_desc;
  

• list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) {
  

•         if ((unsigned long)config_desc->event_ea->var == cfg_hash) {
  

•                 atomic_dec(&config_desc->active_cnt);
  

•                 atomic_dec(&cscfg_mgr->sys_active_cnt);
  

•                 cscfg_owner_put(config_desc->load_owner);
  

•                 dev_dbg(cscfg_device(), "Deactivate config %s.\n", config_desc->name);
  

•                 break;
  

•         }
  

• }
  

+}

+/*

• • called from configfs to set/clear the active configuration for use when
• • using sysfs to control trace.
• */

+int cscfg_config_sysfs_activation(struct cscfg_config_desc *config_desc, bool activate) +{

• unsigned long cfg_hash_desc;
  

• int err = 0;
  

• mutex_lock(&cscfg_mutex);
  

• cfg_hash_desc = (unsigned long)config_desc->event_ea->var;
  

• if (activate) {
  

•         /* cannot be a current active value to activate this */
  

•         if (cscfg_mgr->sysfs_active_config) {
  

•                 err = -EBUSY;
  

•                 goto exit_unlock;
  

•         }
  

•         err = _cscfg_activate_config(cfg_hash_desc);
  

•         if (!err)
  

•                 cscfg_mgr->sysfs_active_config = cfg_hash_desc;
  

• } else {
  

•         /* disable if matching current value */
  

•         if (cscfg_mgr->sysfs_active_config == cfg_hash_desc) {
  

•                 _cscfg_deactivate_config(cfg_hash_desc);
  

•                 cscfg_mgr->sysfs_active_config = 0;
  

•         } else
  

•                 err = -EINVAL;
  

• }
  

+exit_unlock:

• mutex_unlock(&cscfg_mutex);
  

• return err;
  

+}

+/* set the sysfs preset value */ +void cscfg_config_sysfs_preset(int preset) +{

• mutex_lock(&cscfg_mutex);
  

• cscfg_mgr->sysfs_active_preset = preset;
  

• mutex_unlock(&cscfg_mutex);
  

+}

+/**

• • cscfg_activate_config - Mark a configuration descriptor as active.
• • This will be seen when csdev devices are enabled in the system.
• • Only activated configurations can be enabled on individual devices.
• • Activation protects the configuration from alteration or removal while
• • active.
• • Selection by hash value - generated from the configuration name when it
• • was loaded and added to the cs_etm/configurations file system for selection
• • by perf.
• • @cfg_hash: Hash value of the selected configuration name.
• */

+int cscfg_activate_config(unsigned long cfg_hash) +{

• int err = 0;
  

• mutex_lock(&cscfg_mutex);
  

• err = _cscfg_activate_config(cfg_hash);
  mutex_unlock(&cscfg_mutex);
  
  return err;
  

@@ -805,19 +878,8 @@ EXPORT_SYMBOL_GPL(cscfg_activate_config); */ void cscfg_deactivate_config(unsigned long cfg_hash) {

• struct cscfg_config_desc *config_desc;
  

• mutex_lock(&cscfg_mutex);
  

• list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) {
  

•         if ((unsigned long)config_desc->event_ea->var == cfg_hash) {
  

•                 atomic_dec(&config_desc->active_cnt);
  

•                 atomic_dec(&cscfg_mgr->sys_active_cnt);
  

•                 cscfg_owner_put(config_desc->load_owner);
  

•                 dev_dbg(cscfg_device(), "Deactivate config %s.\n", config_desc->name);
  

•                 break;
  

•         }
  

• }
  

• _cscfg_deactivate_config(cfg_hash);
  mutex_unlock(&cscfg_mutex);
  

} EXPORT_SYMBOL_GPL(cscfg_deactivate_config); @@ -826,7 +888,8 @@ EXPORT_SYMBOL_GPL(cscfg_deactivate_config);

• cscfg_csdev_enable_active_config - Enable matching active configuration for device.
• Enables the configuration selected by @cfg_hash if the configuration is supported

• • on the device and has been activated.

• • on the device and has been activated. A @cfg_hash value of 0 is used if the device
• • is being programmed from sysfs, to select the current sysfs active config.
  • If active and supported the CoreSight device @csdev will be programmed with the
  • configuration, using @preset parameters.

@@ -850,6 +913,16 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev, return 0;

  mutex_lock(&cscfg_csdev_mutex);

• /* sysfs controlled coresight will call with cfg_hash == 0 */
  

• if (!cfg_hash) {
  

•         if (!cscfg_mgr->sysfs_active_config)
  

•                 goto exit_unlock;
  

•         cfg_hash = cscfg_mgr->sysfs_active_config;
  

•         preset = cscfg_mgr->sysfs_active_preset;
  

• }
  

I'm worried about this snippet. For the time being it works but the function is now entangled with the "if (attr->config2 ...) of etm4_parse_event_config(). That being said I spent a fair amount of time trying to find a better solution and I can't come up with one. The best option is probably to keep it for now.

...

• list_for_each_entry(config_csdev_item, &csdev->config_csdev_list, node) {
          config_desc = config_csdev_item->config_desc;
          if ((atomic_read(&config_desc->active_cnt)) &&
  

@@ -863,6 +936,8 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev, if (!err) csdev->active_cscfg_ctxt = (void *)config_csdev_active; }

+exit_unlock: mutex_unlock(&cscfg_csdev_mutex); return err; } diff --git a/drivers/hwtracing/coresight/coresight-syscfg.h b/drivers/hwtracing/coresight/coresight-syscfg.h index 1da37874f70f..e07e1b872806 100644 --- a/drivers/hwtracing/coresight/coresight-syscfg.h +++ b/drivers/hwtracing/coresight/coresight-syscfg.h @@ -28,6 +28,8 @@

• @load_order_list: Ordered list of owners for dynamically loaded configurations.
• @sys_active_cnt: Total number of active config descriptor references.
• @cfgfs_subsys: configfs subsystem used to manage configurations.

• • @sysfs_active_config:Active config hash used if CoreSight controlled from sysfs.
• • @sysfs_active_preset:Active preset index used if CoreSight controlled from sysfs.
  */

struct cscfg_manager { struct device dev; @@ -37,6 +39,8 @@ struct cscfg_manager { struct list_head load_order_list; atomic_t sys_active_cnt; struct configfs_subsystem cfgfs_subsys;

• u32 sysfs_active_config;
  

• int sysfs_active_preset;
  

};

/* get reference to dev in cscfg_manager */ @@ -88,7 +92,8 @@ int cscfg_preload(void *owner_handle); const struct cscfg_feature_desc *cscfg_get_named_feat_desc(const char *name); int cscfg_update_feat_param_val(struct cscfg_feature_desc *feat_desc, int param_idx, u64 value);

+int cscfg_config_sysfs_activation(struct cscfg_config_desc *cfg_desc, bool activate); +void cscfg_config_sysfs_preset(int preset);

With the above:

Reviewed-by: Mathieu Poirier mathieu.poirier@linaro.org

Thanks.

Regards

Mike

...

/* syscfg manager external API */ int cscfg_load_config_sets(struct cscfg_config_desc **cfg_descs, -- 2.17.1