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Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lHrAI-009KYA-3L; Thu, 04 Mar 2021 16:49:30 +0000 Received: from foss.arm.com ([217.140.110.172]) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lHrAC-009KX5-8C for linux-arm-kernel@lists.infradead.org; Thu, 04 Mar 2021 16:49:27 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1E9AAD6E; Thu, 4 Mar 2021 08:49:16 -0800 (PST) Received: from [10.57.63.81] (unknown [10.57.63.81]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8C0C83F7D7; Thu, 4 Mar 2021 08:49:13 -0800 (PST) Subject: Re: [PATCH v4 05/10] coresight: syscfg: Add API to activate and enable configurations To: Mike Leach , linux-arm-kernel@lists.infradead.org, coresight@lists.linaro.org, mathieu.poirier@linaro.org, linux-doc@vger.kernel.org Cc: yabinc@google.com, corbet@lwn.net, leo.yan@linaro.org, alexander.shishkin@linux.intel.com, tingwei@codeaurora.org, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org References: <20210128170936.9222-1-mike.leach@linaro.org> <20210128170936.9222-6-mike.leach@linaro.org> From: Suzuki K Poulose Message-ID: <2ff0fd68-969f-292b-f8d3-5dace8f1a435@arm.com> Date: Thu, 4 Mar 2021 16:49:10 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <20210128170936.9222-6-mike.leach@linaro.org> Content-Language: en-GB X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 1/28/21 5:09 PM, Mike Leach wrote: > Configurations are first activated, then when any coresight device is > enabled, the active configurations are checked and any matching > one is enabled. > > This patch provides the activation / enable API. > > Signed-off-by: Mike Leach > --- > .../hwtracing/coresight/coresight-config.h | 2 + > .../hwtracing/coresight/coresight-syscfg.c | 127 ++++++++++++++++++ > .../hwtracing/coresight/coresight-syscfg.h | 10 +- > include/linux/coresight.h | 2 + > 4 files changed, 140 insertions(+), 1 deletion(-) > > diff --git a/drivers/hwtracing/coresight/coresight-config.h b/drivers/hwtracing/coresight/coresight-config.h > index 98380b496046..26396b70c826 100644 > --- a/drivers/hwtracing/coresight/coresight-config.h > +++ b/drivers/hwtracing/coresight/coresight-config.h > @@ -156,6 +156,7 @@ struct cscfg_config_feat_ref { > * @presets: Array of preset values. > * @id_ea: Extended attribute for perf configid value > * @event_ea: Extended attribute for perf event value > + * @active_cnt: ref count for activate on this configuration. > */ > struct cscfg_config_desc { > const char *name; > @@ -168,6 +169,7 @@ struct cscfg_config_desc { > const u64 *presets; /* nr_presets * nr_total_params */ > struct dev_ext_attribute *id_ea; > struct dev_ext_attribute *event_ea; > + atomic_t active_cnt; > }; > > /** > diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c > index a070f135eca3..d79cf5b36758 100644 > --- a/drivers/hwtracing/coresight/coresight-syscfg.c > +++ b/drivers/hwtracing/coresight/coresight-syscfg.c > @@ -298,6 +298,7 @@ static int cscfg_load_config(struct cscfg_config_desc *cfg_desc) > return err; > > list_add(&cfg_desc->item, &cscfg_mgr->data.config_desc_list); > + atomic_set(&cfg_desc->active_cnt, 0); > return 0; > } > > @@ -477,6 +478,131 @@ void cscfg_unregister_csdev(struct coresight_device *csdev) > } > EXPORT_SYMBOL_GPL(cscfg_unregister_csdev); > > +void cscfg_csdev_reset_feats(struct coresight_device *csdev) > +{ > + struct cscfg_feature_csdev *feat; > + > + mutex_lock(&cscfg_csdev_mutex); > + if (list_empty(&csdev->feature_csdev_list)) > + goto unlock_exit; > + > + list_for_each_entry(feat, &csdev->feature_csdev_list, node) > + cscfg_reset_feat(feat); > + > +unlock_exit: > + mutex_unlock(&cscfg_csdev_mutex); > +} > +EXPORT_SYMBOL_GPL(cscfg_csdev_reset_feats); > + > +/** > + * Mark a config descriptor as active. > + * This will be seen when csdev devices are activated in the system. > + * > + * 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) > +{ > + struct cscfg_config_desc *curr_item, *match_item = 0; nit: s/0/NULL > + > + mutex_lock(&cscfg_mutex); > + > + list_for_each_entry(curr_item, &cscfg_mgr->data.config_desc_list, item) { > + if ((unsigned long)curr_item->id_ea->var == cfg_hash) { > + match_item = curr_item; > + atomic_inc(&cscfg_mgr->data.sys_active_cnt); > + break; > + } > + } > + mutex_unlock(&cscfg_mutex); > + > + if (!match_item) > + return -EINVAL; > + > + dev_dbg(to_device_cscfg(), "Activate config %s.\n", match_item->name); > + > + /* mark the descriptors as active so enable config will use them */ > + mutex_lock(&cscfg_csdev_mutex); > + atomic_inc(&match_item->active_cnt); > + mutex_unlock(&cscfg_csdev_mutex); Is there a guarantee that this item is active and present in the list after we dropped the mutex above ? We could certainly nest the mutex as long as we follow the order everywhere to prevent such a race. > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(cscfg_activate_config); > + > +void cscfg_deactivate_config(unsigned long cfg_hash) > +{ > + struct cscfg_config_desc *curr_item, *match_item = 0; > + > + mutex_lock(&cscfg_mutex); > + > + list_for_each_entry(curr_item, &cscfg_mgr->data.config_desc_list, item) { > + if ((unsigned long)curr_item->id_ea->var == cfg_hash) { > + match_item = curr_item; > + break; > + } > + } > + mutex_unlock(&cscfg_mutex); > + if (!match_item) > + return; > + > + dev_dbg(to_device_cscfg(), "Deactivate config %s.\n", match_item->name); > + > + mutex_lock(&cscfg_csdev_mutex); > + atomic_dec(&match_item->active_cnt); > + mutex_unlock(&cscfg_csdev_mutex); > + > + atomic_dec(&cscfg_mgr->data.sys_active_cnt); > +} > +EXPORT_SYMBOL_GPL(cscfg_deactivate_config); > + > +/* Find and program any active config for the supplied device.*/ > +int cscfg_csdev_enable_active_config(struct coresight_device *csdev, > + unsigned long id_hash, int preset) > +{ > + struct cscfg_config_csdev *cfg = NULL, *item; > + const struct cscfg_config_desc *desc; > + int err = 0; > + > + /* quickly check global count */ > + if (!atomic_read(&cscfg_mgr->data.sys_active_cnt)) > + return 0; > + > + mutex_lock(&cscfg_csdev_mutex); > + list_for_each_entry(item, &csdev->config_csdev_list, node) { > + desc = item->desc; > + if ((atomic_read(&desc->active_cnt)) && > + ((unsigned long)desc->id_ea->var == id_hash)) { > + cfg = item; > + break; > + } > + } > + if (cfg) { > + err = cscfg_csdev_enable_config(cfg, preset); > + if (!err) > + csdev->active_cfg_ctxt = (void *)cfg; > + } > + mutex_unlock(&cscfg_csdev_mutex); > + return err; > +} > +EXPORT_SYMBOL_GPL(cscfg_csdev_enable_active_config); > + > +/* save and disable the active config for the device */ > +void cscfg_csdev_disable_active_config(struct coresight_device *csdev) > +{ > + struct cscfg_config_csdev *cfg; > + > + mutex_lock(&cscfg_csdev_mutex); > + cfg = (struct cscfg_config_csdev *)csdev->active_cfg_ctxt; > + if (cfg) > + cscfg_csdev_disable_config(cfg); > + mutex_unlock(&cscfg_csdev_mutex); > +} > +EXPORT_SYMBOL_GPL(cscfg_csdev_disable_active_config); > + > /* Initialise system configuration management device. */ > > struct device *to_device_cscfg(void) > @@ -546,6 +672,7 @@ int __init cscfg_init(void) > INIT_LIST_HEAD(&cscfg_mgr->data.feat_desc_list); > INIT_LIST_HEAD(&cscfg_mgr->data.config_desc_list); > cscfg_mgr->data.nr_csdev = 0; > + atomic_set(&cscfg_mgr->data.sys_active_cnt, 0); > > dev_info(to_device_cscfg(), "CoreSight Configuration manager initialised"); > return 0; > diff --git a/drivers/hwtracing/coresight/coresight-syscfg.h b/drivers/hwtracing/coresight/coresight-syscfg.h > index ebf5e1491d86..301e26e1e98f 100644 > --- a/drivers/hwtracing/coresight/coresight-syscfg.h > +++ b/drivers/hwtracing/coresight/coresight-syscfg.h > @@ -17,13 +17,15 @@ > * @csdev_list: List of coresight devices registered with the configuration manager. > * @feat_desc_list: List of feature descriptors to load into registered devices. nit: Is this aligned ? (It is from Patch 1, though). > * @config_desc_list: List of system configuration descriptors to load into registered devices. > - * @nr_csdev: Number of registered devices with the cscfg system > + * @nr_csdev: Number of registered devices with the cscfg system Spurious change ? > + * @sys_active_cnt: Total number of active config descriptor references. > */ > struct cscfg_api_data { > struct list_head csdev_desc_list; > struct list_head feat_desc_list; > struct list_head config_desc_list; > int nr_csdev; > + atomic_t sys_active_cnt; > }; > > /** > @@ -53,6 +55,12 @@ int cscfg_register_csdev(struct coresight_device *csdev, > struct cscfg_match_desc *info, > struct cscfg_csdev_feat_ops *ops); > void cscfg_unregister_csdev(struct coresight_device *csdev); > +int cscfg_activate_config(unsigned long cfg_hash); > +void cscfg_deactivate_config(unsigned long cfg_hash); > +void cscfg_csdev_reset_feats(struct coresight_device *csdev); > +int cscfg_csdev_enable_active_config(struct coresight_device *csdev, > + unsigned long id_hash, int preset); > +void cscfg_csdev_disable_active_config(struct coresight_device *csdev); > > /** > * System configuration manager device. > diff --git a/include/linux/coresight.h b/include/linux/coresight.h > index d0126ed326a6..3941854e8280 100644 > --- a/include/linux/coresight.h > +++ b/include/linux/coresight.h > @@ -221,6 +221,7 @@ struct coresight_sysfs_link { > * @has_conns_grp: Have added a "connections" group for sysfs links. > * @feature_csdev_list: List of complex feature programming added to the device. > * @config_csdev_list: List of system configurations added to the device. > + * @active_cfg_ctxt: Context information for current active congfig. > */ > struct coresight_device { > struct coresight_platform_data *pdata; > @@ -245,6 +246,7 @@ struct coresight_device { > /* system configuration and feature lists */ > struct list_head feature_csdev_list; > struct list_head config_csdev_list; > + void *active_cfg_ctxt; > }; > Suzuki _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel