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Sat, 25 May 2024 01:26:59 GMT Received: from hu-clew-lv.qualcomm.com (10.49.16.6) by nalasex01a.na.qualcomm.com (10.47.209.196) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.9; Fri, 24 May 2024 18:26:58 -0700 From: Chris Lew Date: Fri, 24 May 2024 18:26:40 -0700 Subject: [PATCH v2 1/4] hwspinlock: Introduce hwspin_lock_bust() Precedence: bulk X-Mailing-List: linux-arm-msm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <20240524-hwspinlock-bust-v2-1-fb88fd17ca0b@quicinc.com> References: <20240524-hwspinlock-bust-v2-0-fb88fd17ca0b@quicinc.com> In-Reply-To: <20240524-hwspinlock-bust-v2-0-fb88fd17ca0b@quicinc.com> To: Bjorn Andersson , Baolin Wang , Peter Zijlstra , "Ingo Molnar" , Will Deacon , Waiman Long , Boqun Feng , Jonathan Corbet , Mathieu Poirier , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Manivannan Sadhasivam , Konrad Dybcio CC: , , , , , Chris Lew , "Richard Maina" X-Mailer: b4 0.12.4 X-Developer-Signature: v=1; a=ed25519-sha256; t=1716600418; l=5095; i=quic_clew@quicinc.com; s=20240508; h=from:subject:message-id; bh=q4xVZjavTkorT8lY9Lzg3Rsu0INrOCVJpnlNKtqizbM=; b=Rj4eRQ1tnfKR4Jm30fFi0Wa5MN6iR5G5OLNTu61biNA2Ih+bWuQG16l7/Q6prBns3z0AcnLQi KTjBlWunSx5ArkORS/F1NzN448IKCjDHQ03Y5pTV1wbE8/NGqdRuMEP X-Developer-Key: i=quic_clew@quicinc.com; a=ed25519; pk=lEYKFaL1H5dMC33BEeOULLcHAwjKyHkTLdLZQRDTKV4= X-ClientProxiedBy: nalasex01a.na.qualcomm.com (10.47.209.196) To nalasex01a.na.qualcomm.com (10.47.209.196) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-ORIG-GUID: OEKY9ZIK4tf_2O9UgEsID1brhYtfDAIk X-Proofpoint-GUID: OEKY9ZIK4tf_2O9UgEsID1brhYtfDAIk X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1039,Hydra:6.0.650,FMLib:17.12.28.16 definitions=2024-05-24_09,2024-05-24_01,2024-05-17_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 phishscore=0 suspectscore=0 malwarescore=0 bulkscore=0 priorityscore=1501 mlxscore=0 mlxlogscore=999 impostorscore=0 lowpriorityscore=0 spamscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2405170001 definitions=main-2405250009 From: Richard Maina When a remoteproc crashes or goes down unexpectedly this can result in a state where locks held by the remoteproc will remain locked possibly resulting in deadlock. This new API hwspin_lock_bust() allows hwspinlock implementers to define a bust operation for freeing previously acquired hwspinlocks after verifying ownership of the acquired lock. Signed-off-by: Richard Maina Signed-off-by: Chris Lew --- Documentation/locking/hwspinlock.rst | 11 +++++++++++ drivers/hwspinlock/hwspinlock_core.c | 28 ++++++++++++++++++++++++++++ drivers/hwspinlock/hwspinlock_internal.h | 3 +++ include/linux/hwspinlock.h | 6 ++++++ 4 files changed, 48 insertions(+) diff --git a/Documentation/locking/hwspinlock.rst b/Documentation/locking/hwspinlock.rst index 6f03713b7003..2ffaa3cbd63f 100644 --- a/Documentation/locking/hwspinlock.rst +++ b/Documentation/locking/hwspinlock.rst @@ -85,6 +85,17 @@ is already free). Should be called from a process context (might sleep). +:: + + int hwspin_lock_bust(struct hwspinlock *hwlock, unsigned int id); + +After verifying the owner of the hwspinlock, release a previously acquired +hwspinlock; returns 0 on success, or an appropriate error code on failure +(e.g. -EOPNOTSUPP if the bust operation is not defined for the specific +hwspinlock). + +Should be called from a process context (might sleep). + :: int hwspin_lock_timeout(struct hwspinlock *hwlock, unsigned int timeout); diff --git a/drivers/hwspinlock/hwspinlock_core.c b/drivers/hwspinlock/hwspinlock_core.c index 0c0a932c00f3..6505261e6068 100644 --- a/drivers/hwspinlock/hwspinlock_core.c +++ b/drivers/hwspinlock/hwspinlock_core.c @@ -305,6 +305,34 @@ void __hwspin_unlock(struct hwspinlock *hwlock, int mode, unsigned long *flags) } EXPORT_SYMBOL_GPL(__hwspin_unlock); +/** + * hwspin_lock_bust() - bust a specific hwspinlock + * @hwlock: a previously-acquired hwspinlock which we want to bust + * @id: identifier of the remote lock holder, if applicable + * + * This function will bust a hwspinlock that was previously acquired as + * long as the current owner of the lock matches the id given by the caller. + * + * Context: Process context. + * + * Returns: 0 on success, or -EINVAL if the hwspinlock does not exist, or + * the bust operation fails, and -EOPNOTSUPP if the bust operation is not + * defined for the hwspinlock. + */ +int hwspin_lock_bust(struct hwspinlock *hwlock, unsigned int id) +{ + if (WARN_ON(!hwlock)) + return -EINVAL; + + if (!hwlock->bank->ops->bust) { + pr_err("bust operation not defined\n"); + return -EOPNOTSUPP; + } + + return hwlock->bank->ops->bust(hwlock, id); +} +EXPORT_SYMBOL_GPL(hwspin_lock_bust); + /** * of_hwspin_lock_simple_xlate - translate hwlock_spec to return a lock id * @hwlock_spec: hwlock specifier as found in the device tree diff --git a/drivers/hwspinlock/hwspinlock_internal.h b/drivers/hwspinlock/hwspinlock_internal.h index 29892767bb7a..f298fc0ee5ad 100644 --- a/drivers/hwspinlock/hwspinlock_internal.h +++ b/drivers/hwspinlock/hwspinlock_internal.h @@ -21,6 +21,8 @@ struct hwspinlock_device; * @trylock: make a single attempt to take the lock. returns 0 on * failure and true on success. may _not_ sleep. * @unlock: release the lock. always succeed. may _not_ sleep. + * @bust: optional, platform-specific bust handler, called by hwspinlock + * core to bust a specific lock. * @relax: optional, platform-specific relax handler, called by hwspinlock * core while spinning on a lock, between two successive * invocations of @trylock. may _not_ sleep. @@ -28,6 +30,7 @@ struct hwspinlock_device; struct hwspinlock_ops { int (*trylock)(struct hwspinlock *lock); void (*unlock)(struct hwspinlock *lock); + int (*bust)(struct hwspinlock *lock, unsigned int id); void (*relax)(struct hwspinlock *lock); }; diff --git a/include/linux/hwspinlock.h b/include/linux/hwspinlock.h index bfe7c1f1ac6d..f0231dbc4777 100644 --- a/include/linux/hwspinlock.h +++ b/include/linux/hwspinlock.h @@ -68,6 +68,7 @@ int __hwspin_lock_timeout(struct hwspinlock *, unsigned int, int, int __hwspin_trylock(struct hwspinlock *, int, unsigned long *); void __hwspin_unlock(struct hwspinlock *, int, unsigned long *); int of_hwspin_lock_get_id_byname(struct device_node *np, const char *name); +int hwspin_lock_bust(struct hwspinlock *hwlock, unsigned int id); int devm_hwspin_lock_free(struct device *dev, struct hwspinlock *hwlock); struct hwspinlock *devm_hwspin_lock_request(struct device *dev); struct hwspinlock *devm_hwspin_lock_request_specific(struct device *dev, @@ -127,6 +128,11 @@ void __hwspin_unlock(struct hwspinlock *hwlock, int mode, unsigned long *flags) { } +static inline int hwspin_lock_bust(struct hwspinlock *hwlock, unsigned int id) +{ + return 0; +} + static inline int of_hwspin_lock_get_id(struct device_node *np, int index) { return 0;