From patchwork Mon Nov 25 09:48:08 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yeoreum Yun X-Patchwork-Id: 13884758 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 563C7D3B7F8 for ; Mon, 25 Nov 2024 10:17:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Zo5mimbPUNYnoumTueh0t1mauAGjhvK+A4v7TYhBmH8=; b=HOWJki/NNg+gQIzz8tiZZnfzce BPt1w0AWgC5dIV6MVtf4ndUaaMch0ieL6/nGGqz59RCOHqLzlfiTdoQ6AtXv5ImffYaVkMFok2hTW XPc7Qy79skh5OSVTPPFPkD9AxdsI4bEzGhiYk6x/UBzV7F97nb0vZp7wCwWxutYOEdyFs0IeMi4ku p8IlgEQuKDDWctjMJqJrmL1Pj44KaYSyqZSkVtBK6VLznXjLZwEhBnxneHz4A/ZRFXMSdxfly6YwE rww39StYNyv6+KXrzAt1MTkdzTxgMcD6kcl48wSyxCJqDSoZRrFyMtK3/I4I8OsO9ifgMKqN3pHfQ 19uAcOIg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tFW9s-00000007hkq-13IU; Mon, 25 Nov 2024 10:17:32 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tFVhg-00000007div-166U for linux-arm-kernel@lists.infradead.org; Mon, 25 Nov 2024 09:48:25 +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 76EE21756; Mon, 25 Nov 2024 01:48:53 -0800 (PST) Received: from e129823.cambridge.arm.com (e129823.arm.com [10.1.197.6]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 407E23F66E; Mon, 25 Nov 2024 01:48:21 -0800 (PST) From: Yeoreum Yun To: suzuki.poulose@arm.com, mike.leach@linaro.org, james.clark@linaro.org, alexander.shishkin@linux.intel.com, bigeasy@linutronix.de, clrkwllms@kernel.org, rostedt@goodmis.org Cc: coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, nd@arm.com, Levi Yun Subject: [PATCH 1/9] coresight: change coresight_device lock type to raw_spinlock_t Date: Mon, 25 Nov 2024 09:48:08 +0000 Message-Id: <20241125094816.365472-2-yeoreum.yun@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20241125094816.365472-1-yeoreum.yun@arm.com> References: <20241125094816.365472-1-yeoreum.yun@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241125_014824_391871_978D5842 X-CRM114-Status: GOOD ( 19.18 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Levi Yun coresight_device->cscfg_csdev_lock can be held during __schedule() by perf_event_task_sched_out()/in(). Since coresight->cscfg_csdev_lock type is spinlock_t and perf_event_task_sched_out()/in() is called after acquiring rq_lock, which is raw_spinlock_t (an unsleepable lock), this poses an issue in PREEMPT_RT kernel where spinlock_t is sleepable. To address this, change type of coresight_device->cscfg_csdev_lock from spinlock_t to raw_spinlock_t. Signed-off-by: Yeoreum Yun --- .../hwtracing/coresight/coresight-syscfg.c | 75 +++++++++---------- include/linux/coresight.h | 2 +- 2 files changed, 35 insertions(+), 42 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c index 11138a9762b0..b7e9fb822e8f 100644 --- a/drivers/hwtracing/coresight/coresight-syscfg.c +++ b/drivers/hwtracing/coresight/coresight-syscfg.c @@ -65,7 +65,6 @@ static int cscfg_add_csdev_cfg(struct coresight_device *csdev, { struct cscfg_config_csdev *config_csdev = NULL; struct cscfg_feature_csdev *feat_csdev; - unsigned long flags; int i; /* look at each required feature and see if it matches any feature on the device */ @@ -89,9 +88,9 @@ static int cscfg_add_csdev_cfg(struct coresight_device *csdev, } /* if matched features, add config to device.*/ if (config_csdev) { - spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); - list_add(&config_csdev->node, &csdev->config_csdev_list); - spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); + scoped_guard(raw_spinlock_irqsave, &csdev->cscfg_csdev_lock) { + list_add(&config_csdev->node, &csdev->config_csdev_list); + } } return 0; @@ -177,7 +176,6 @@ static int cscfg_load_feat_csdev(struct coresight_device *csdev, struct cscfg_csdev_feat_ops *ops) { struct cscfg_feature_csdev *feat_csdev; - unsigned long flags; int err; if (!ops->load_feat) @@ -194,9 +192,9 @@ static int cscfg_load_feat_csdev(struct coresight_device *csdev, /* add to internal csdev feature list & initialise using reset call */ cscfg_reset_feat(feat_csdev); - spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); - list_add(&feat_csdev->node, &csdev->feature_csdev_list); - spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); + scoped_guard(raw_spinlock_irqsave, &csdev->cscfg_csdev_lock) { + list_add(&feat_csdev->node, &csdev->feature_csdev_list); + } return 0; } @@ -765,7 +763,7 @@ static int cscfg_list_add_csdev(struct coresight_device *csdev, INIT_LIST_HEAD(&csdev->feature_csdev_list); INIT_LIST_HEAD(&csdev->config_csdev_list); - spin_lock_init(&csdev->cscfg_csdev_lock); + raw_spin_lock_init(&csdev->cscfg_csdev_lock); return 0; } @@ -853,17 +851,14 @@ EXPORT_SYMBOL_GPL(cscfg_unregister_csdev); void cscfg_csdev_reset_feats(struct coresight_device *csdev) { struct cscfg_feature_csdev *feat_csdev; - unsigned long flags; - spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); + guard(raw_spinlock_irqsave)(&csdev->cscfg_csdev_lock); + if (list_empty(&csdev->feature_csdev_list)) - goto unlock_exit; + return; list_for_each_entry(feat_csdev, &csdev->feature_csdev_list, node) cscfg_reset_feat(feat_csdev); - -unlock_exit: - spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); } EXPORT_SYMBOL_GPL(cscfg_csdev_reset_feats); @@ -1048,7 +1043,6 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev, { struct cscfg_config_csdev *config_csdev_active = NULL, *config_csdev_item; const struct cscfg_config_desc *config_desc; - unsigned long flags; int err = 0; /* quickly check global count */ @@ -1059,17 +1053,17 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev, * Look for matching configuration - set the active configuration * context if found. */ - spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); - 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; - csdev->active_cscfg_ctxt = (void *)config_csdev_active; - break; + scoped_guard(raw_spinlock_irqsave, &csdev->cscfg_csdev_lock) { + 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; + csdev->active_cscfg_ctxt = (void *)config_csdev_active; + break; + } } } - spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); /* * If found, attempt to enable @@ -1090,12 +1084,12 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev, * * Set enabled if OK, err if not. */ - spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); - if (csdev->active_cscfg_ctxt) - config_csdev_active->enabled = true; - else - err = -EBUSY; - spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); + scoped_guard(raw_spinlock_irqsave, &csdev->cscfg_csdev_lock) { + if (csdev->active_cscfg_ctxt) + config_csdev_active->enabled = true; + else + err = -EBUSY; + } } } return err; @@ -1117,23 +1111,22 @@ EXPORT_SYMBOL_GPL(cscfg_csdev_enable_active_config); void cscfg_csdev_disable_active_config(struct coresight_device *csdev) { struct cscfg_config_csdev *config_csdev; - unsigned long flags; /* * Check if we have an active config, and that it was successfully enabled. * If it was not enabled, we have no work to do, otherwise mark as disabled. * Clear the active config pointer. */ - spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); - config_csdev = (struct cscfg_config_csdev *)csdev->active_cscfg_ctxt; - if (config_csdev) { - if (!config_csdev->enabled) - config_csdev = NULL; - else - config_csdev->enabled = false; + scoped_guard(raw_spinlock_irqsave, &csdev->cscfg_csdev_lock) { + config_csdev = (struct cscfg_config_csdev *)csdev->active_cscfg_ctxt; + if (config_csdev) { + if (!config_csdev->enabled) + config_csdev = NULL; + else + config_csdev->enabled = false; + } + csdev->active_cscfg_ctxt = NULL; } - csdev->active_cscfg_ctxt = NULL; - spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); /* true if there was an enabled active config */ if (config_csdev) diff --git a/include/linux/coresight.h b/include/linux/coresight.h index c13342594278..924b58c343b3 100644 --- a/include/linux/coresight.h +++ b/include/linux/coresight.h @@ -296,7 +296,7 @@ struct coresight_device { /* system configuration and feature lists */ struct list_head feature_csdev_list; struct list_head config_csdev_list; - spinlock_t cscfg_csdev_lock; + raw_spinlock_t cscfg_csdev_lock; void *active_cscfg_ctxt; };