From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0216AC48BC2 for ; Fri, 25 Jun 2021 15:09:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DBE65616E8 for ; Fri, 25 Jun 2021 15:09:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231878AbhFYPLm (ORCPT ); Fri, 25 Jun 2021 11:11:42 -0400 Received: from foss.arm.com ([217.140.110.172]:58274 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229653AbhFYPLl (ORCPT ); Fri, 25 Jun 2021 11:11:41 -0400 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 7C86F1042; Fri, 25 Jun 2021 08:09:20 -0700 (PDT) Received: from [10.57.77.225] (unknown [10.57.77.225]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 446E33F694; Fri, 25 Jun 2021 08:09:18 -0700 (PDT) Subject: Re: [PATCH v7 05/10] coresight: syscfg: Add API to activate and enable configurations To: Mike Leach , Mathieu Poirier Cc: Branislav Rankov , linux-arm-kernel , Coresight ML , "open list:DOCUMENTATION" , Yabin Cui , Jon Corbet , Leo Yan , Alexander Shishkin , Tingwei Zhang , Greg KH , Linux Kernel Mailing List , nd References: <20210414191903.18349-1-mike.leach@linaro.org> <20210414191903.18349-6-mike.leach@linaro.org> From: Suzuki K Poulose Message-ID: <815e1569-7e46-7891-4982-f3d38d734658@arm.com> Date: Fri, 25 Jun 2021 16:09:16 +0100 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 25/06/2021 15:37, Mike Leach wrote: > HI Branislav, Mathieu, > > I have started to look into this as a top priority. > > However, when I enable the CONFIG_DEBUG_ option my board fails to boot > at all. (Dragonboard DB410c), so the resolution make take a little > time. > > At this point I am assuming that the mutex will need to be replaced by > a spinlock - so a re-design + v8 set may well be required. Or may be a refcount on the "config" instance may work too ? i.e, when the config is loaded onto a device, a refcount could be taken on the config and dropped on unload. Whoever drops it to zero could release it. Thoughts ? Suzuki > > Regards > > Mike > > On Mon, 14 Jun 2021 at 18:03, Mathieu Poirier > wrote: >> >> Hi Branislav, >> >> On Thu, 10 Jun 2021 at 05:05, Branislav Rankov wrote: >>> >>> >>> On 4/14/21 8:18 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 >>>> Reviewed-by: Mathieu Poirier >>>> --- >>>> .../hwtracing/coresight/coresight-config.h | 2 + >>>> .../hwtracing/coresight/coresight-syscfg.c | 172 ++++++++++++++++++ >>>> .../hwtracing/coresight/coresight-syscfg.h | 8 + >>>> include/linux/coresight.h | 2 + >>>> 4 files changed, 184 insertions(+) >>>> >>>> diff --git a/drivers/hwtracing/coresight/coresight-config.h b/drivers/hwtracing/coresight/coresight-config.h >>>> index 0667581822c1..25eb6c632692 100644 >>>> --- a/drivers/hwtracing/coresight/coresight-config.h >>>> +++ b/drivers/hwtracing/coresight/coresight-config.h >>>> @@ -127,6 +127,7 @@ struct cscfg_feature_desc { >>>> * @nr_total_params: Sum of all parameters declared by used features >>>> * @presets: Array of preset values. >>>> * @event_ea: Extended attribute for perf event value >>>> + * @active_cnt: ref count for activate on this configuration. >>>> * >>>> */ >>>> struct cscfg_config_desc { >>>> @@ -139,6 +140,7 @@ struct cscfg_config_desc { >>>> int nr_total_params; >>>> const u64 *presets; /* nr_presets * nr_total_params */ >>>> 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 e35f8c0ac2f8..b234e45c153f 100644 >>>> --- a/drivers/hwtracing/coresight/coresight-syscfg.c >>>> +++ b/drivers/hwtracing/coresight/coresight-syscfg.c >>>> @@ -283,6 +283,7 @@ static int cscfg_load_config(struct cscfg_config_desc *config_desc) >>>> return err; >>>> >>>> list_add(&config_desc->item, &cscfg_mgr->config_desc_list); >>>> + atomic_set(&config_desc->active_cnt, 0); >>>> return 0; >>>> } >>>> >>>> @@ -468,6 +469,176 @@ void cscfg_unregister_csdev(struct coresight_device *csdev) >>>> } >>>> EXPORT_SYMBOL_GPL(cscfg_unregister_csdev); >>>> >>>> +/** >>>> + * cscfg_csdev_reset_feats - reset features for a CoreSight device. >>>> + * >>>> + * Resets all parameters and register values for any features loaded >>>> + * into @csdev to their default values. >>>> + * >>>> + * @csdev: The CoreSight device. >>>> + */ >>>> +void cscfg_csdev_reset_feats(struct coresight_device *csdev) >>>> +{ >>>> + struct cscfg_feature_csdev *feat_csdev; >>>> + >>>> + mutex_lock(&cscfg_csdev_mutex); >>>> + if (list_empty(&csdev->feature_csdev_list)) >>>> + goto unlock_exit; >>>> + >>>> + list_for_each_entry(feat_csdev, &csdev->feature_csdev_list, node) >>>> + cscfg_reset_feat(feat_csdev); >>>> + >>>> +unlock_exit: >>>> + mutex_unlock(&cscfg_csdev_mutex); >>>> +} >>>> +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. >>>> + * >>>> + * 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) >>>> +{ >>>> + 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) { >>>> + /* >>>> + * increment the global active count - control changes to >>>> + * active configurations >>>> + */ >>>> + atomic_inc(&cscfg_mgr->sys_active_cnt); >>>> + >>>> + /* >>>> + * mark the descriptor as active so enable config on a >>>> + * device instance will use it >>>> + */ >>>> + atomic_inc(&config_desc->active_cnt); >>>> + >>>> + err = 0; >>>> + dev_dbg(cscfg_device(), "Activate config %s.\n", config_desc->name); >>>> + break; >>>> + } >>>> + } >>>> + mutex_unlock(&cscfg_mutex); >>>> + >>>> + return err; >>>> +} >>>> +EXPORT_SYMBOL_GPL(cscfg_activate_config); >>>> + >>>> +/** >>>> + * cscfg_deactivate_config - Mark a config descriptor as inactive. >>>> + * >>>> + * Decrement the configuration and global active counts. >>>> + * >>>> + * @cfg_hash: Hash value of the selected configuration name. >>>> + */ >>>> +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); >>>> + dev_dbg(cscfg_device(), "Deactivate config %s.\n", config_desc->name); >>>> + break; >>>> + } >>>> + } >>>> + mutex_unlock(&cscfg_mutex); >>>> +} >>>> +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. >>>> + * >>>> + * If active and supported the CoreSight device @csdev will be programmed with the >>>> + * configuration, using @preset parameters. >>>> + * >>>> + * Should be called before driver hardware enable for the requested device, prior to >>>> + * programming and enabling the physical hardware. >>>> + * >>>> + * @csdev: CoreSight device to program. >>>> + * @cfg_hash: Selector for the configuration. >>>> + * @preset: Preset parameter values to use, 0 for current / default values. >>>> + */ >>>> +int cscfg_csdev_enable_active_config(struct coresight_device *csdev, >>>> + unsigned long cfg_hash, int preset) >>>> +{ >>>> + struct cscfg_config_csdev *config_csdev_active = NULL, *config_csdev_item; >>>> + const struct cscfg_config_desc *config_desc; >>>> + int err = 0; >>>> + >>>> + /* quickly check global count */ >>>> + if (!atomic_read(&cscfg_mgr->sys_active_cnt)) >>>> + return 0; >>>> + >>>> + mutex_lock(&cscfg_csdev_mutex); >>>> + 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)) && >>>> + ((unsigned long)config_desc->event_ea->var == cfg_hash)) { >>>> + config_csdev_active = config_csdev_item; >>>> + break; >>>> + } >>>> + } >>>> + if (config_csdev_active) { >>>> + err = cscfg_csdev_enable_config(config_csdev_active, preset); >>>> + if (!err) >>>> + csdev->active_cscfg_ctxt = (void *)config_csdev_active; >>>> + } >>>> + mutex_unlock(&cscfg_csdev_mutex); >>>> + return err; >>>> +} >>>> +EXPORT_SYMBOL_GPL(cscfg_csdev_enable_active_config); >>>> + >>>> +/** >>>> + * cscfg_csdev_disable_active_config - disable an active config on the device. >>>> + * >>>> + * Disables the active configuration on the CoreSight device @csdev. >>>> + * Disable will save the values of any registers marked in the configurations >>>> + * as save on disable. >>>> + * >>>> + * Should be called after driver hardware disable for the requested device, >>>> + * after disabling the physical hardware and reading back registers. >>>> + * >>>> + * @csdev: The CoreSight device. >>>> + */ >>>> +void cscfg_csdev_disable_active_config(struct coresight_device *csdev) >>>> +{ >>>> + struct cscfg_config_csdev *config_csdev; >>>> + >>>> + mutex_lock(&cscfg_csdev_mutex); >>> >>> This line seems to cause a bug report when the kernel is compiled with CONFIG_DEBUG_ATOMIC_SLEEP=y >>> >>> I have tested this by applying the series to 5.10 kernel on Dragonboard 845c. >>> >>> It only happens when strobing is used. >> >> Thanks for reporting this. Unfortunately Mike is away and likely >> won't be able to look at this in time for the merge window. As such I >> backed out the complex configuration feature from the next branch but >> that code is still available on next-complex-configuration. >> >> Thanks, >> Mathieu >> >>> >>> The report is this: >>> >>> [13431.885395] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:283 >>> [13431.893919] in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 3525, name: perf >>> [13431.901882] CPU: 0 PID: 3525 Comm: perf Tainted: G W 5.10.0-rc5-17282-g923b456a55fb #124 >>> [13431.911436] Hardware name: Thundercomm Dragonboard 845c (DT) >>> [13431.917450] Call trace: >>> [13431.919938] dump_backtrace+0x0/0x1a0 >>> [13431.923644] show_stack+0x18/0x68 >>> [13431.927008] dump_stack+0xd0/0x12c >>> [13431.930444] ___might_sleep+0xf0/0x130 >>> [13431.934228] __might_sleep+0x54/0x90 >>> [13431.937945] mutex_lock+0x28/0x80 >>> [13431.941468] cscfg_csdev_disable_active_config+0x24/0x50 >>> [13431.946952] etm4_disable+0xf0/0x100 >>> [13431.950571] etm_event_stop+0xb8/0x130 >>> [13431.954380] etm_event_del+0x14/0x20 >>> [13431.958008] event_sched_out.isra.0+0x84/0x1c8 >>> [13431.962496] group_sched_out.part.0+0x44/0xc8 >>> [13431.967010] __perf_event_disable+0xe4/0x198 >>> [13431.971549] event_function+0x8c/0xe8 >>> [13431.975256] remote_function+0x64/0x78 >>> [13431.979161] generic_exec_single+0xa0/0x100 >>> [13431.983876] smp_call_function_single+0x158/0x1d8 >>> [13431.988629] event_function_call+0x128/0x138 >>> [13431.992942] _perf_event_disable+0x48/0x70 >>> [13431.997082] perf_event_for_each_child+0x3c/0x90 >>> [13432.001751] _perf_ioctl+0x198/0x4a8 >>> [13432.005359] perf_ioctl+0x4c/0x78 >>> [13432.008715] __arm64_sys_ioctl+0xa8/0xf0 >>> [13432.012835] el0_svc_common.constprop.0+0x78/0x1a0 >>> [13432.017767] do_el0_svc+0x24/0x90 >>> [13432.021616] el0_sync_handler+0x160/0x168 >>> [13432.025670] el0_sync+0x174/0x180 >>> >>> >>>> + config_csdev = (struct cscfg_config_csdev *)csdev->active_cscfg_ctxt; >>>> + if (config_csdev) { >>>> + cscfg_csdev_disable_config(config_csdev); >>>> + csdev->active_cscfg_ctxt = NULL; >>>> + } >>>> + mutex_unlock(&cscfg_csdev_mutex); >>>> +} >>>> +EXPORT_SYMBOL_GPL(cscfg_csdev_disable_active_config); >>>> + >>>> /* Initialise system configuration management device. */ >>>> >>>> struct device *cscfg_device(void) >>>> @@ -536,6 +707,7 @@ int __init cscfg_init(void) >>>> INIT_LIST_HEAD(&cscfg_mgr->csdev_desc_list); >>>> INIT_LIST_HEAD(&cscfg_mgr->feat_desc_list); >>>> INIT_LIST_HEAD(&cscfg_mgr->config_desc_list); >>>> + atomic_set(&cscfg_mgr->sys_active_cnt, 0); >>>> >>>> dev_info(cscfg_device(), "CoreSight Configuration manager initialised"); >>>> return 0; >>>> diff --git a/drivers/hwtracing/coresight/coresight-syscfg.h b/drivers/hwtracing/coresight/coresight-syscfg.h >>>> index 5bcae3b374c6..a52775890670 100644 >>>> --- a/drivers/hwtracing/coresight/coresight-syscfg.h >>>> +++ b/drivers/hwtracing/coresight/coresight-syscfg.h >>>> @@ -24,12 +24,14 @@ >>>> * @csdev_desc_list: List of coresight devices registered with the configuration manager. >>>> * @feat_desc_list: List of feature descriptors to load into registered devices. >>>> * @config_desc_list: List of system configuration descriptors to load into registered devices. >>>> + * @sys_active_cnt: Total number of active config descriptor references. >>>> */ >>>> struct cscfg_manager { >>>> struct device dev; >>>> struct list_head csdev_desc_list; >>>> struct list_head feat_desc_list; >>>> struct list_head config_desc_list; >>>> + atomic_t sys_active_cnt; >>>> }; >>>> >>>> /* get reference to dev in cscfg_manager */ >>>> @@ -61,5 +63,11 @@ int cscfg_load_config_sets(struct cscfg_config_desc **cfg_descs, >>>> int cscfg_register_csdev(struct coresight_device *csdev, u32 match_flags, >>>> 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 cfg_hash, int preset); >>>> +void cscfg_csdev_disable_active_config(struct coresight_device *csdev); >>>> >>>> #endif /* CORESIGHT_SYSCFG_H */ >>>> diff --git a/include/linux/coresight.h b/include/linux/coresight.h >>>> index 6fb516e1b22e..a348049ee08b 100644 >>>> --- a/include/linux/coresight.h >>>> +++ b/include/linux/coresight.h >>>> @@ -222,6 +222,7 @@ 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_cscfg_ctxt: Context information for current active system configuration. >>>> */ >>>> struct coresight_device { >>>> struct coresight_platform_data *pdata; >>>> @@ -246,6 +247,7 @@ struct coresight_device { >>>> /* system configuration and feature lists */ >>>> struct list_head feature_csdev_list; >>>> struct list_head config_csdev_list; >>>> + void *active_cscfg_ctxt; >>>> }; >>>> >>>> /* >>>> > > > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 80CFBC2B9F4 for ; Fri, 25 Jun 2021 15:10:56 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3B7EF61428 for ; Fri, 25 Jun 2021 15:10:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3B7EF61428 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:Cc:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=qaJhLsOqKTCON0RyjQMkxE6/rv40Emg3ASVfCvlVKo0=; b=tDLEhl08Yq0wJoljte+5fGep1r gH050O6c57y39X2B0dNhjoluyggLnCcjMJ2NNgdOAM2skqzrQ1ptUPKurkhhe1YL+roD+PlhyYBRn NzDfDlLNb1+2Bx3vxZrLVTdPcb5D10Si6BlN4lGbG+8ItGro0L4hs7bC/aGni+y6C5MMaeP/cu3je RR96Rp4MwxPSLcSFyFGKWEKm7mAequ88urJRuvdhZUtIxPxrlltQnucmRjw5n5HB4m0AOKTc7i/Kj rgQPuJoLQ+zUe21JUK7gwMuUa03Y39ly2c3zAG6992F/EXjec69Z9Ei9peFKeUr60cPvC9D2WvEtm BIc6z2Nw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lwnSS-00261c-Sf; Fri, 25 Jun 2021 15:09:29 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lwnSO-00260b-At for linux-arm-kernel@lists.infradead.org; Fri, 25 Jun 2021 15:09:26 +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 7C86F1042; Fri, 25 Jun 2021 08:09:20 -0700 (PDT) Received: from [10.57.77.225] (unknown [10.57.77.225]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 446E33F694; Fri, 25 Jun 2021 08:09:18 -0700 (PDT) Subject: Re: [PATCH v7 05/10] coresight: syscfg: Add API to activate and enable configurations To: Mike Leach , Mathieu Poirier Cc: Branislav Rankov , linux-arm-kernel , Coresight ML , "open list:DOCUMENTATION" , Yabin Cui , Jon Corbet , Leo Yan , Alexander Shishkin , Tingwei Zhang , Greg KH , Linux Kernel Mailing List , nd References: <20210414191903.18349-1-mike.leach@linaro.org> <20210414191903.18349-6-mike.leach@linaro.org> From: Suzuki K Poulose Message-ID: <815e1569-7e46-7891-4982-f3d38d734658@arm.com> Date: Fri, 25 Jun 2021 16:09:16 +0100 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-GB X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210625_080924_540562_3B78B78D X-CRM114-Status: GOOD ( 41.15 ) 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 25/06/2021 15:37, Mike Leach wrote: > HI Branislav, Mathieu, > > I have started to look into this as a top priority. > > However, when I enable the CONFIG_DEBUG_ option my board fails to boot > at all. (Dragonboard DB410c), so the resolution make take a little > time. > > At this point I am assuming that the mutex will need to be replaced by > a spinlock - so a re-design + v8 set may well be required. Or may be a refcount on the "config" instance may work too ? i.e, when the config is loaded onto a device, a refcount could be taken on the config and dropped on unload. Whoever drops it to zero could release it. Thoughts ? Suzuki > > Regards > > Mike > > On Mon, 14 Jun 2021 at 18:03, Mathieu Poirier > wrote: >> >> Hi Branislav, >> >> On Thu, 10 Jun 2021 at 05:05, Branislav Rankov wrote: >>> >>> >>> On 4/14/21 8:18 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 >>>> Reviewed-by: Mathieu Poirier >>>> --- >>>> .../hwtracing/coresight/coresight-config.h | 2 + >>>> .../hwtracing/coresight/coresight-syscfg.c | 172 ++++++++++++++++++ >>>> .../hwtracing/coresight/coresight-syscfg.h | 8 + >>>> include/linux/coresight.h | 2 + >>>> 4 files changed, 184 insertions(+) >>>> >>>> diff --git a/drivers/hwtracing/coresight/coresight-config.h b/drivers/hwtracing/coresight/coresight-config.h >>>> index 0667581822c1..25eb6c632692 100644 >>>> --- a/drivers/hwtracing/coresight/coresight-config.h >>>> +++ b/drivers/hwtracing/coresight/coresight-config.h >>>> @@ -127,6 +127,7 @@ struct cscfg_feature_desc { >>>> * @nr_total_params: Sum of all parameters declared by used features >>>> * @presets: Array of preset values. >>>> * @event_ea: Extended attribute for perf event value >>>> + * @active_cnt: ref count for activate on this configuration. >>>> * >>>> */ >>>> struct cscfg_config_desc { >>>> @@ -139,6 +140,7 @@ struct cscfg_config_desc { >>>> int nr_total_params; >>>> const u64 *presets; /* nr_presets * nr_total_params */ >>>> 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 e35f8c0ac2f8..b234e45c153f 100644 >>>> --- a/drivers/hwtracing/coresight/coresight-syscfg.c >>>> +++ b/drivers/hwtracing/coresight/coresight-syscfg.c >>>> @@ -283,6 +283,7 @@ static int cscfg_load_config(struct cscfg_config_desc *config_desc) >>>> return err; >>>> >>>> list_add(&config_desc->item, &cscfg_mgr->config_desc_list); >>>> + atomic_set(&config_desc->active_cnt, 0); >>>> return 0; >>>> } >>>> >>>> @@ -468,6 +469,176 @@ void cscfg_unregister_csdev(struct coresight_device *csdev) >>>> } >>>> EXPORT_SYMBOL_GPL(cscfg_unregister_csdev); >>>> >>>> +/** >>>> + * cscfg_csdev_reset_feats - reset features for a CoreSight device. >>>> + * >>>> + * Resets all parameters and register values for any features loaded >>>> + * into @csdev to their default values. >>>> + * >>>> + * @csdev: The CoreSight device. >>>> + */ >>>> +void cscfg_csdev_reset_feats(struct coresight_device *csdev) >>>> +{ >>>> + struct cscfg_feature_csdev *feat_csdev; >>>> + >>>> + mutex_lock(&cscfg_csdev_mutex); >>>> + if (list_empty(&csdev->feature_csdev_list)) >>>> + goto unlock_exit; >>>> + >>>> + list_for_each_entry(feat_csdev, &csdev->feature_csdev_list, node) >>>> + cscfg_reset_feat(feat_csdev); >>>> + >>>> +unlock_exit: >>>> + mutex_unlock(&cscfg_csdev_mutex); >>>> +} >>>> +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. >>>> + * >>>> + * 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) >>>> +{ >>>> + 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) { >>>> + /* >>>> + * increment the global active count - control changes to >>>> + * active configurations >>>> + */ >>>> + atomic_inc(&cscfg_mgr->sys_active_cnt); >>>> + >>>> + /* >>>> + * mark the descriptor as active so enable config on a >>>> + * device instance will use it >>>> + */ >>>> + atomic_inc(&config_desc->active_cnt); >>>> + >>>> + err = 0; >>>> + dev_dbg(cscfg_device(), "Activate config %s.\n", config_desc->name); >>>> + break; >>>> + } >>>> + } >>>> + mutex_unlock(&cscfg_mutex); >>>> + >>>> + return err; >>>> +} >>>> +EXPORT_SYMBOL_GPL(cscfg_activate_config); >>>> + >>>> +/** >>>> + * cscfg_deactivate_config - Mark a config descriptor as inactive. >>>> + * >>>> + * Decrement the configuration and global active counts. >>>> + * >>>> + * @cfg_hash: Hash value of the selected configuration name. >>>> + */ >>>> +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); >>>> + dev_dbg(cscfg_device(), "Deactivate config %s.\n", config_desc->name); >>>> + break; >>>> + } >>>> + } >>>> + mutex_unlock(&cscfg_mutex); >>>> +} >>>> +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. >>>> + * >>>> + * If active and supported the CoreSight device @csdev will be programmed with the >>>> + * configuration, using @preset parameters. >>>> + * >>>> + * Should be called before driver hardware enable for the requested device, prior to >>>> + * programming and enabling the physical hardware. >>>> + * >>>> + * @csdev: CoreSight device to program. >>>> + * @cfg_hash: Selector for the configuration. >>>> + * @preset: Preset parameter values to use, 0 for current / default values. >>>> + */ >>>> +int cscfg_csdev_enable_active_config(struct coresight_device *csdev, >>>> + unsigned long cfg_hash, int preset) >>>> +{ >>>> + struct cscfg_config_csdev *config_csdev_active = NULL, *config_csdev_item; >>>> + const struct cscfg_config_desc *config_desc; >>>> + int err = 0; >>>> + >>>> + /* quickly check global count */ >>>> + if (!atomic_read(&cscfg_mgr->sys_active_cnt)) >>>> + return 0; >>>> + >>>> + mutex_lock(&cscfg_csdev_mutex); >>>> + 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)) && >>>> + ((unsigned long)config_desc->event_ea->var == cfg_hash)) { >>>> + config_csdev_active = config_csdev_item; >>>> + break; >>>> + } >>>> + } >>>> + if (config_csdev_active) { >>>> + err = cscfg_csdev_enable_config(config_csdev_active, preset); >>>> + if (!err) >>>> + csdev->active_cscfg_ctxt = (void *)config_csdev_active; >>>> + } >>>> + mutex_unlock(&cscfg_csdev_mutex); >>>> + return err; >>>> +} >>>> +EXPORT_SYMBOL_GPL(cscfg_csdev_enable_active_config); >>>> + >>>> +/** >>>> + * cscfg_csdev_disable_active_config - disable an active config on the device. >>>> + * >>>> + * Disables the active configuration on the CoreSight device @csdev. >>>> + * Disable will save the values of any registers marked in the configurations >>>> + * as save on disable. >>>> + * >>>> + * Should be called after driver hardware disable for the requested device, >>>> + * after disabling the physical hardware and reading back registers. >>>> + * >>>> + * @csdev: The CoreSight device. >>>> + */ >>>> +void cscfg_csdev_disable_active_config(struct coresight_device *csdev) >>>> +{ >>>> + struct cscfg_config_csdev *config_csdev; >>>> + >>>> + mutex_lock(&cscfg_csdev_mutex); >>> >>> This line seems to cause a bug report when the kernel is compiled with CONFIG_DEBUG_ATOMIC_SLEEP=y >>> >>> I have tested this by applying the series to 5.10 kernel on Dragonboard 845c. >>> >>> It only happens when strobing is used. >> >> Thanks for reporting this. Unfortunately Mike is away and likely >> won't be able to look at this in time for the merge window. As such I >> backed out the complex configuration feature from the next branch but >> that code is still available on next-complex-configuration. >> >> Thanks, >> Mathieu >> >>> >>> The report is this: >>> >>> [13431.885395] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:283 >>> [13431.893919] in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 3525, name: perf >>> [13431.901882] CPU: 0 PID: 3525 Comm: perf Tainted: G W 5.10.0-rc5-17282-g923b456a55fb #124 >>> [13431.911436] Hardware name: Thundercomm Dragonboard 845c (DT) >>> [13431.917450] Call trace: >>> [13431.919938] dump_backtrace+0x0/0x1a0 >>> [13431.923644] show_stack+0x18/0x68 >>> [13431.927008] dump_stack+0xd0/0x12c >>> [13431.930444] ___might_sleep+0xf0/0x130 >>> [13431.934228] __might_sleep+0x54/0x90 >>> [13431.937945] mutex_lock+0x28/0x80 >>> [13431.941468] cscfg_csdev_disable_active_config+0x24/0x50 >>> [13431.946952] etm4_disable+0xf0/0x100 >>> [13431.950571] etm_event_stop+0xb8/0x130 >>> [13431.954380] etm_event_del+0x14/0x20 >>> [13431.958008] event_sched_out.isra.0+0x84/0x1c8 >>> [13431.962496] group_sched_out.part.0+0x44/0xc8 >>> [13431.967010] __perf_event_disable+0xe4/0x198 >>> [13431.971549] event_function+0x8c/0xe8 >>> [13431.975256] remote_function+0x64/0x78 >>> [13431.979161] generic_exec_single+0xa0/0x100 >>> [13431.983876] smp_call_function_single+0x158/0x1d8 >>> [13431.988629] event_function_call+0x128/0x138 >>> [13431.992942] _perf_event_disable+0x48/0x70 >>> [13431.997082] perf_event_for_each_child+0x3c/0x90 >>> [13432.001751] _perf_ioctl+0x198/0x4a8 >>> [13432.005359] perf_ioctl+0x4c/0x78 >>> [13432.008715] __arm64_sys_ioctl+0xa8/0xf0 >>> [13432.012835] el0_svc_common.constprop.0+0x78/0x1a0 >>> [13432.017767] do_el0_svc+0x24/0x90 >>> [13432.021616] el0_sync_handler+0x160/0x168 >>> [13432.025670] el0_sync+0x174/0x180 >>> >>> >>>> + config_csdev = (struct cscfg_config_csdev *)csdev->active_cscfg_ctxt; >>>> + if (config_csdev) { >>>> + cscfg_csdev_disable_config(config_csdev); >>>> + csdev->active_cscfg_ctxt = NULL; >>>> + } >>>> + mutex_unlock(&cscfg_csdev_mutex); >>>> +} >>>> +EXPORT_SYMBOL_GPL(cscfg_csdev_disable_active_config); >>>> + >>>> /* Initialise system configuration management device. */ >>>> >>>> struct device *cscfg_device(void) >>>> @@ -536,6 +707,7 @@ int __init cscfg_init(void) >>>> INIT_LIST_HEAD(&cscfg_mgr->csdev_desc_list); >>>> INIT_LIST_HEAD(&cscfg_mgr->feat_desc_list); >>>> INIT_LIST_HEAD(&cscfg_mgr->config_desc_list); >>>> + atomic_set(&cscfg_mgr->sys_active_cnt, 0); >>>> >>>> dev_info(cscfg_device(), "CoreSight Configuration manager initialised"); >>>> return 0; >>>> diff --git a/drivers/hwtracing/coresight/coresight-syscfg.h b/drivers/hwtracing/coresight/coresight-syscfg.h >>>> index 5bcae3b374c6..a52775890670 100644 >>>> --- a/drivers/hwtracing/coresight/coresight-syscfg.h >>>> +++ b/drivers/hwtracing/coresight/coresight-syscfg.h >>>> @@ -24,12 +24,14 @@ >>>> * @csdev_desc_list: List of coresight devices registered with the configuration manager. >>>> * @feat_desc_list: List of feature descriptors to load into registered devices. >>>> * @config_desc_list: List of system configuration descriptors to load into registered devices. >>>> + * @sys_active_cnt: Total number of active config descriptor references. >>>> */ >>>> struct cscfg_manager { >>>> struct device dev; >>>> struct list_head csdev_desc_list; >>>> struct list_head feat_desc_list; >>>> struct list_head config_desc_list; >>>> + atomic_t sys_active_cnt; >>>> }; >>>> >>>> /* get reference to dev in cscfg_manager */ >>>> @@ -61,5 +63,11 @@ int cscfg_load_config_sets(struct cscfg_config_desc **cfg_descs, >>>> int cscfg_register_csdev(struct coresight_device *csdev, u32 match_flags, >>>> 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 cfg_hash, int preset); >>>> +void cscfg_csdev_disable_active_config(struct coresight_device *csdev); >>>> >>>> #endif /* CORESIGHT_SYSCFG_H */ >>>> diff --git a/include/linux/coresight.h b/include/linux/coresight.h >>>> index 6fb516e1b22e..a348049ee08b 100644 >>>> --- a/include/linux/coresight.h >>>> +++ b/include/linux/coresight.h >>>> @@ -222,6 +222,7 @@ 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_cscfg_ctxt: Context information for current active system configuration. >>>> */ >>>> struct coresight_device { >>>> struct coresight_platform_data *pdata; >>>> @@ -246,6 +247,7 @@ struct coresight_device { >>>> /* system configuration and feature lists */ >>>> struct list_head feature_csdev_list; >>>> struct list_head config_csdev_list; >>>> + void *active_cscfg_ctxt; >>>> }; >>>> >>>> /* >>>> > > > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel