From nobody Fri Dec 19 17:16:05 2025 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 F21315674D; Mon, 19 Feb 2024 22:39:35 +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=1708382381; cv=none; b=q0qT0INtZ07R8RUyu7Hd7BeU72WQH5388F8mXQypeSdmZAJVAMR6HVXTZrl97Y8Yz3PHTZdmn+dWc3XMw01mLbLyerEaJ6orBVisc708cU/xWO7fWdWjrW4EWTvCZIxdlCgMJkKYO4PwV2l05kBflGe3xRAVvpY/g3TMuhVy6rI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708382381; c=relaxed/simple; bh=fdEV6NvWPOr3H9DhWoCHZa8j5eufVwiEJHht5U0PHvE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bhc5v8VtO4KHL6zbj3K80mSKQPFW4lt5ilRCtWebyIywez03YeobF3MosnI+GDIlWRMxh/jz/P7+Ik9S+sIjnO6TNjjNWMhpy5Ka+5AIexCGkZfB0901lLL0d7OER9ZQCBylymdemXatPyHaou5ZYL5YQ/SUrjn9c6ON1y+qM50= 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=U2GbVPBm; 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="U2GbVPBm" 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=Nr8IOHHYhllR3HYtyEHbvyYMxtrQLzWrxlWMFjNl1S0=; b=U2GbVPBmcPv0ue+WIVhjwir5Wb zp0OzBobNKawn6rZnuX92KR13VVogrx23btfdDwHYXt5ceF8EXvdmsNZQTy90JzvdMPGcWp7OjFYi CCXNu7N1dKbs8qH0hNOONcwHzjWStVBtYOEVdK0G9FeNR1pqdz220S7smBPW4C+3L8k9n8cb7KMQ7 Oh03as2J1iogXCYyI249kNWtAuxkzxxurEEzCfVl97YTb3QQ/GUZ6CA2mIdNMOEIXW7rDk2dpRgob YROzom9ELXZpX7B105sIHyk9bntWG0oRtcb+yJgZXBcSwxFQ8VTMXSLeGf8TafPO77qPBZfUwA+wH BmQHxmTQ==; 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 1rcCIL-0037Oz-0D; Mon, 19 Feb 2024 16:39:29 -0600 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 , Elizabeth Figura Subject: [PATCH v2 03/31] ntsync: Introduce NTSYNC_IOC_SEM_POST. Date: Mon, 19 Feb 2024 16:38:05 -0600 Message-ID: <20240219223833.95710-4-zfigura@codeweavers.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240219223833.95710-1-zfigura@codeweavers.com> References: <20240219223833.95710-1-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 NtReleaseSemaphore(). This increases the semaphore's internal counter by the given value, and ret= urns the previous value. If the counter would overflow the defined maximum, the function instead fails and returns -EOVERFLOW. Signed-off-by: Elizabeth Figura --- drivers/misc/ntsync.c | 72 +++++++++++++++++++++++++++++++++++-- include/uapi/linux/ntsync.h | 2 ++ 2 files changed, 71 insertions(+), 3 deletions(-) diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c index 20158ec148bc..3c2f743c58b0 100644 --- a/drivers/misc/ntsync.c +++ b/drivers/misc/ntsync.c @@ -10,7 +10,9 @@ #include #include #include +#include #include +#include #include =20 #define NTSYNC_NAME "ntsync" @@ -31,23 +33,70 @@ enum ntsync_type { */ =20 struct ntsync_obj { + spinlock_t lock; + enum ntsync_type type; =20 + struct file *file; + struct ntsync_device *dev; + + /* The following fields are protected by the object lock. */ union { struct { __u32 count; __u32 max; } sem; } u; - - struct file *file; - struct ntsync_device *dev; }; =20 struct ntsync_device { struct file *file; }; =20 +/* + * Actually change the semaphore state, returning -EOVERFLOW if it is made + * invalid. + */ +static int post_sem_state(struct ntsync_obj *sem, __u32 count) +{ + __u32 sum; + + lockdep_assert_held(&sem->lock); + + if (check_add_overflow(sem->u.sem.count, count, &sum) || + sum > sem->u.sem.max) + return -EOVERFLOW; + + sem->u.sem.count =3D sum; + return 0; +} + +static int ntsync_sem_post(struct ntsync_obj *sem, void __user *argp) +{ + __u32 __user *user_args =3D argp; + __u32 prev_count; + __u32 args; + int ret; + + if (copy_from_user(&args, argp, sizeof(args))) + return -EFAULT; + + if (sem->type !=3D NTSYNC_TYPE_SEM) + return -EINVAL; + + spin_lock(&sem->lock); + + prev_count =3D sem->u.sem.count; + ret =3D post_sem_state(sem, args); + + spin_unlock(&sem->lock); + + if (!ret && put_user(prev_count, user_args)) + ret =3D -EFAULT; + + return ret; +} + static int ntsync_obj_release(struct inode *inode, struct file *file) { struct ntsync_obj *obj =3D file->private_data; @@ -58,9 +107,25 @@ static int ntsync_obj_release(struct inode *inode, stru= ct file *file) return 0; } =20 +static long ntsync_obj_ioctl(struct file *file, unsigned int cmd, + unsigned long parm) +{ + struct ntsync_obj *obj =3D file->private_data; + void __user *argp =3D (void __user *)parm; + + switch (cmd) { + case NTSYNC_IOC_SEM_POST: + return ntsync_sem_post(obj, argp); + default: + return -ENOIOCTLCMD; + } +} + static const struct file_operations ntsync_obj_fops =3D { .owner =3D THIS_MODULE, .release =3D ntsync_obj_release, + .unlocked_ioctl =3D ntsync_obj_ioctl, + .compat_ioctl =3D compat_ptr_ioctl, .llseek =3D no_llseek, }; =20 @@ -75,6 +140,7 @@ static struct ntsync_obj *ntsync_alloc_obj(struct ntsync= _device *dev, obj->type =3D type; obj->dev =3D dev; get_file(dev->file); + spin_lock_init(&obj->lock); =20 return obj; } diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h index 6a4867a6c97b..dcfa38fdc93c 100644 --- a/include/uapi/linux/ntsync.h +++ b/include/uapi/linux/ntsync.h @@ -18,4 +18,6 @@ struct ntsync_sem_args { =20 #define NTSYNC_IOC_CREATE_SEM _IOWR('N', 0x80, struct ntsync_sem_args) =20 +#define NTSYNC_IOC_SEM_POST _IOWR('N', 0x81, __u32) + #endif --=20 2.43.0