From nobody Mon Feb 9 16:33:25 2026 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 0941A191F7A for ; Mon, 25 Nov 2024 09:48:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732528106; cv=none; b=avoRn5L4dh+xmY9wCP8wBrBKHPE25yoc6HSLQyRCbwncrLaXlrIGhAA0lkhMDEmW2ApLJjcE6326FwTmFe86bM8NZoITr+0WoBW1V26tpJQLG7gpdxJwrE5S3oquGQPYUAEYVk8PFAimCoc7v8xrsg9toJCqxELxeYpqySJA3js= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732528106; c=relaxed/simple; bh=eIqVdQjaWI7rfmZALNqUneIC3BHaMRK+BwsAKDTiM2Q=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=pn7Z95aDcam8SrA8H7+oObgAmD+fe9+xK/OpW5PkN03I/9PLjdYXTMy5QHzS7lotgvJJoQf1Z7CmwGB5uuf+cL0+9RK0PZp8vleNCtArV/hP8uJ6W0oVr09lVqPgSULU5KMuFTGXy8XwgVs+jMOLzuqFrsF2ozrlZowmc2JQzrM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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/hwtra= cing/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 *c= sdev, { struct cscfg_config_csdev *config_csdev =3D NULL; struct cscfg_feature_csdev *feat_csdev; - unsigned long flags; int i; =20 /* 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 *c= sdev, } /* 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); + } } =20 return 0; @@ -177,7 +176,6 @@ static int cscfg_load_feat_csdev(struct coresight_devic= e *csdev, struct cscfg_csdev_feat_ops *ops) { struct cscfg_feature_csdev *feat_csdev; - unsigned long flags; int err; =20 if (!ops->load_feat) @@ -194,9 +192,9 @@ static int cscfg_load_feat_csdev(struct coresight_devic= e *csdev, =20 /* 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); + } =20 return 0; } @@ -765,7 +763,7 @@ static int cscfg_list_add_csdev(struct coresight_device= *csdev, =20 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); =20 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; =20 - 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; =20 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); =20 @@ -1048,7 +1043,6 @@ int cscfg_csdev_enable_active_config(struct coresight= _device *csdev, { struct cscfg_config_csdev *config_csdev_active =3D NULL, *config_csdev_it= em; const struct cscfg_config_desc *config_desc; - unsigned long flags; int err =3D 0; =20 /* quickly check global count */ @@ -1059,17 +1053,17 @@ int cscfg_csdev_enable_active_config(struct coresig= ht_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 =3D config_csdev_item->config_desc; - if ((atomic_read(&config_desc->active_cnt)) && - ((unsigned long)config_desc->event_ea->var =3D=3D cfg_hash)) { - config_csdev_active =3D config_csdev_item; - csdev->active_cscfg_ctxt =3D (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 =3D config_csdev_item->config_desc; + if ((atomic_read(&config_desc->active_cnt)) && + ((unsigned long)config_desc->event_ea->var =3D=3D cfg_hash)) { + config_csdev_active =3D config_csdev_item; + csdev->active_cscfg_ctxt =3D (void *)config_csdev_active; + break; + } } } - spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); =20 /* * If found, attempt to enable @@ -1090,12 +1084,12 @@ int cscfg_csdev_enable_active_config(struct coresig= ht_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 =3D true; - else - err =3D -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 =3D true; + else + err =3D -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; =20 /* * Check if we have an active config, and that it was successfully enable= d. * If it was not enabled, we have no work to do, otherwise mark as disabl= ed. * Clear the active config pointer. */ - spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); - config_csdev =3D (struct cscfg_config_csdev *)csdev->active_cscfg_ctxt; - if (config_csdev) { - if (!config_csdev->enabled) - config_csdev =3D NULL; - else - config_csdev->enabled =3D false; + scoped_guard(raw_spinlock_irqsave, &csdev->cscfg_csdev_lock) { + config_csdev =3D (struct cscfg_config_csdev *)csdev->active_cscfg_ctxt; + if (config_csdev) { + if (!config_csdev->enabled) + config_csdev =3D NULL; + else + config_csdev->enabled =3D false; + } + csdev->active_cscfg_ctxt =3D NULL; } - csdev->active_cscfg_ctxt =3D NULL; - spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); =20 /* 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; }; =20 --=20 LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}