From nobody Wed Feb 11 04:18:39 2026 Received: from mail.codeweavers.com (mail.codeweavers.com [4.36.192.163]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 71D29745FD; Sun, 19 May 2024 20:25:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=4.36.192.163 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716150321; cv=none; b=LRGjb/siA/yxA5OAImSgYqiyuTBsgUMkW72QrQ9jDFVxagVCAvO11jt8zfEDGbTEHwUAKdh+iLKsr+XyxrIRCqG+0AQ1z6F2PiOYzlOayfn4b2bt4G8Yr4QY3MbhG7m99lJFBSUlinS9tm5GHm3qbjcsjQ9EmGdbR+Rb+O9rVcA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716150321; c=relaxed/simple; bh=O6pZ7douG1wzU+ulrX8Og0hWJD7BuLVJKerv0vxm/10=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=S/k2XMuZKPgY0R96Cvp6943rW4+7ffXTW9pcAZIdYMZ0/KBYGLCfXxJolmTxtKcNnvwQC8hzggIdwVWHTwBU2fzFhpzSFfijl3ms4VvtA8GWUyqBw4RWmXrBT/tFBg4BK/eJJHrMkebDcq5AeBoWz8MWzGaEmH/FtcS17Par0QU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=codeweavers.com; spf=pass smtp.mailfrom=codeweavers.com; dkim=pass (2048-bit key) header.d=codeweavers.com header.i=@codeweavers.com header.b=UxpKGxEf; arc=none smtp.client-ip=4.36.192.163 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=codeweavers.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=codeweavers.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=codeweavers.com header.i=@codeweavers.com header.b="UxpKGxEf" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=codeweavers.com; s=s1; h=Message-ID:Date:Subject:Cc:To:From:Sender; bh=Q3igaEQxpSWMeILoj0hVqmOUYjiaFqrzya8EJNTRHxM=; b=UxpKGxEfEjkYwB4SS7myShHCO6 K+rnS3v/QIdGY4D9ZMsNgzX75LMmx3PTw0DtqU7SIGoAJ0buZv4lHU+cisPNLc95CJoEPZnOZsC6j TGDoXrbp3p24C/hATSDohSpcjlut64PzbPWzGbS3ndt3IqC3HKu/Zqsnd5M7H6Dp1AEmy0xNGeSl/ okB2D8HwY6NPPyUR+2udcYbtWCGemumleBFomdwl0boIzByhr2oyEfj38/HWVjY6Y7YPb+6cayBqd TgTN3Jf9jg0aYxPTllA1KK4nvKmiDaS6p9PNK+O/Z7Xd60XS83eGK0TykhTFuBChImBpUGdre+HDV xd/6B7Bg==; Received: from cw137ip160.mn.codeweavers.com ([10.69.137.160] helo=camazotz.mn.codeweavers.com) by mail.codeweavers.com with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1s8n5b-008wIn-1a; Sun, 19 May 2024 15:25:03 -0500 From: Elizabeth Figura To: Arnd Bergmann , Greg Kroah-Hartman , Jonathan Corbet , Shuah Khan Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, wine-devel@winehq.org, =?UTF-8?q?Andr=C3=A9=20Almeida?= , Wolfram Sang , Arkadiusz Hiler , Peter Zijlstra , Andy Lutomirski , linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Randy Dunlap , Ingo Molnar , Will Deacon , Waiman Long , Boqun Feng , Elizabeth Figura Subject: [PATCH v5 03/28] ntsync: Introduce NTSYNC_IOC_CREATE_MUTEX. Date: Sun, 19 May 2024 15:24:29 -0500 Message-ID: <20240519202454.1192826-4-zfigura@codeweavers.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240519202454.1192826-1-zfigura@codeweavers.com> References: <20240519202454.1192826-1-zfigura@codeweavers.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" This corresponds to the NT syscall NtCreateMutant(). An NT mutex is recursive, with a 32-bit recursion counter. When acquired via NtWaitForMultipleObjects(), the recursion counter is incremented by one. Th= e OS records the thread which acquired it. The OS records the thread which acquired it. However, in order to keep this driver self-contained, the owning thread ID is managed by user-space, and p= assed as a parameter to all relevant ioctls. The initial owner and recursion count, if any, are specified when the mutex= is created. Signed-off-by: Elizabeth Figura --- drivers/misc/ntsync.c | 77 +++++++++++++++++++++++++++++++++++-- include/uapi/linux/ntsync.h | 10 ++++- 2 files changed, 83 insertions(+), 4 deletions(-) diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c index a2f2dfadc3ee..cfe802c79d7d 100644 --- a/drivers/misc/ntsync.c +++ b/drivers/misc/ntsync.c @@ -25,6 +25,7 @@ =20 enum ntsync_type { NTSYNC_TYPE_SEM, + NTSYNC_TYPE_MUTEX, }; =20 /* @@ -55,6 +56,10 @@ struct ntsync_obj { __u32 count; __u32 max; } sem; + struct { + __u32 count; + pid_t owner; + } mutex; } u; =20 /* @@ -92,6 +97,7 @@ struct ntsync_q_entry { =20 struct ntsync_q { struct task_struct *task; + __u32 owner; =20 /* * Protected via atomic_try_cmpxchg(). Only the thread that wins the @@ -214,13 +220,17 @@ static void ntsync_unlock_obj(struct ntsync_device *d= ev, struct ntsync_obj *obj, ((lockdep_is_held(&(obj)->dev->wait_all_lock) !=3D LOCK_STATE_NOT= _HELD) && \ (obj)->dev_locked)) =20 -static bool is_signaled(struct ntsync_obj *obj) +static bool is_signaled(struct ntsync_obj *obj, __u32 owner) { ntsync_assert_held(obj); =20 switch (obj->type) { case NTSYNC_TYPE_SEM: return !!obj->u.sem.count; + case NTSYNC_TYPE_MUTEX: + if (obj->u.mutex.owner && obj->u.mutex.owner !=3D owner) + return false; + return obj->u.mutex.count < UINT_MAX; } =20 WARN(1, "bad object type %#x\n", obj->type); @@ -250,7 +260,7 @@ static void try_wake_all(struct ntsync_device *dev, str= uct ntsync_q *q, } =20 for (i =3D 0; i < count; i++) { - if (!is_signaled(q->entries[i].obj)) { + if (!is_signaled(q->entries[i].obj, q->owner)) { can_wake =3D false; break; } @@ -264,6 +274,10 @@ static void try_wake_all(struct ntsync_device *dev, st= ruct ntsync_q *q, case NTSYNC_TYPE_SEM: obj->u.sem.count--; break; + case NTSYNC_TYPE_MUTEX: + obj->u.mutex.count++; + obj->u.mutex.owner =3D q->owner; + break; } } wake_up_process(q->task); @@ -307,6 +321,30 @@ static void try_wake_any_sem(struct ntsync_obj *sem) } } =20 +static void try_wake_any_mutex(struct ntsync_obj *mutex) +{ + struct ntsync_q_entry *entry; + + ntsync_assert_held(mutex); + lockdep_assert(mutex->type =3D=3D NTSYNC_TYPE_MUTEX); + + list_for_each_entry(entry, &mutex->any_waiters, node) { + struct ntsync_q *q =3D entry->q; + int signaled =3D -1; + + if (mutex->u.mutex.count =3D=3D UINT_MAX) + break; + if (mutex->u.mutex.owner && mutex->u.mutex.owner !=3D q->owner) + continue; + + if (atomic_try_cmpxchg(&q->signaled, &signaled, entry->index)) { + mutex->u.mutex.count++; + mutex->u.mutex.owner =3D q->owner; + wake_up_process(q->task); + } + } +} + /* * Actually change the semaphore state, returning -EOVERFLOW if it is made * invalid. @@ -455,6 +493,33 @@ static int ntsync_create_sem(struct ntsync_device *dev= , void __user *argp) return put_user(fd, &user_args->sem); } =20 +static int ntsync_create_mutex(struct ntsync_device *dev, void __user *arg= p) +{ + struct ntsync_mutex_args __user *user_args =3D argp; + struct ntsync_mutex_args args; + struct ntsync_obj *mutex; + int fd; + + if (copy_from_user(&args, argp, sizeof(args))) + return -EFAULT; + + if (!args.owner !=3D !args.count) + return -EINVAL; + + mutex =3D ntsync_alloc_obj(dev, NTSYNC_TYPE_MUTEX); + if (!mutex) + return -ENOMEM; + mutex->u.mutex.count =3D args.count; + mutex->u.mutex.owner =3D args.owner; + fd =3D ntsync_obj_get_fd(mutex); + if (fd < 0) { + kfree(mutex); + return fd; + } + + return put_user(fd, &user_args->mutex); +} + static struct ntsync_obj *get_obj(struct ntsync_device *dev, int fd) { struct file *file =3D fget(fd); @@ -524,7 +589,7 @@ static int setup_wait(struct ntsync_device *dev, struct ntsync_q *q; __u32 i, j; =20 - if (args->pad[0] || args->pad[1] || args->pad[2] || (args->flags & ~NTSYN= C_WAIT_REALTIME)) + if (args->pad[0] || args->pad[1] || (args->flags & ~NTSYNC_WAIT_REALTIME)) return -EINVAL; =20 if (args->count > NTSYNC_MAX_WAIT_COUNT) @@ -538,6 +603,7 @@ static int setup_wait(struct ntsync_device *dev, if (!q) return -ENOMEM; q->task =3D current; + q->owner =3D args->owner; atomic_set(&q->signaled, -1); q->all =3D all; q->count =3D count; @@ -580,6 +646,9 @@ static void try_wake_any_obj(struct ntsync_obj *obj) case NTSYNC_TYPE_SEM: try_wake_any_sem(obj); break; + case NTSYNC_TYPE_MUTEX: + try_wake_any_mutex(obj); + break; } } =20 @@ -769,6 +838,8 @@ static long ntsync_char_ioctl(struct file *file, unsign= ed int cmd, void __user *argp =3D (void __user *)parm; =20 switch (cmd) { + case NTSYNC_IOC_CREATE_MUTEX: + return ntsync_create_mutex(dev, argp); case NTSYNC_IOC_CREATE_SEM: return ntsync_create_sem(dev, argp); case NTSYNC_IOC_WAIT_ALL: diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h index addf187b1573..d5e5a2fbcb4d 100644 --- a/include/uapi/linux/ntsync.h +++ b/include/uapi/linux/ntsync.h @@ -16,6 +16,12 @@ struct ntsync_sem_args { __u32 max; }; =20 +struct ntsync_mutex_args { + __u32 mutex; + __u32 owner; + __u32 count; +}; + #define NTSYNC_WAIT_REALTIME 0x1 =20 struct ntsync_wait_args { @@ -24,7 +30,8 @@ struct ntsync_wait_args { __u32 count; __u32 index; __u32 flags; - __u32 pad[3]; + __u32 owner; + __u32 pad[2]; }; =20 #define NTSYNC_MAX_WAIT_COUNT 64 @@ -32,6 +39,7 @@ struct ntsync_wait_args { #define NTSYNC_IOC_CREATE_SEM _IOWR('N', 0x80, struct ntsync_sem_args) #define NTSYNC_IOC_WAIT_ANY _IOWR('N', 0x82, struct ntsync_wait_args) #define NTSYNC_IOC_WAIT_ALL _IOWR('N', 0x83, struct ntsync_wait_args) +#define NTSYNC_IOC_CREATE_MUTEX _IOWR('N', 0x84, struct ntsync_sem_args) =20 #define NTSYNC_IOC_SEM_POST _IOWR('N', 0x81, __u32) =20 --=20 2.43.0